Related Applications

This application claims the benefit of U.S. provisional patent application number 63/309,777 entitled, "Method of Designing and Producing Fiber-Reinforced Polymer Tappets", filed February 14, 2022, inventors Bryan Gill, Brennan C. Lieu, and Aaron Guo, and which is hereby incorporated herein in its entirety.

Field of Invention

The present application relates to manufacturing components for an internal combustion engine. Specifically, the application pertains to tappets and tie bars of tappets located in the valve train of the engine, and methods of designing and producing tappets and tie bars.

Background

Tappets, alternatively called lifters, are structures which translate the rotational motion of camshafts into vertical forces. Tappets are used to open and close the intake and exhaust valves of a cylinder thereby allowing the chemical reactions that power an engine. Flat tappets are solid structures that glide over the camshaft. Roller tappets have wheels to roll over the camshaft, reducing wear and allowing aggressive eccentric camshaft lobes. Roller tappets must be aligned with the camshaft using tie bars that connect to two tappets, keyways that align the tappet in a bushing, or flat spots that align the tappet with a lifter tray or a dog bone.

To keep the tappets in contact with the camshaft profile, high spring pressures are required in the valve train. The high spring pressures exert extreme compressive force on the tappets. High performance tappets are designed to tolerate extreme compressive forces. If the forces exceed the yield strength of the tappets, failure of the tappet occurs. Failure of tappets generally occurs in the needle bearing which sends needle shrapnel through the engine, causing damage to other parts in the engine and thereby leading to catastrophic failure. Therefore, to avoid catastrophic failure, tappets need to be replaced often.

High performance tappets are generally made from tool steel alloys to withstand the extreme compressive loads in a valve train. However, these alloys have a high density, and therefore have heavier mass and weight. Lighter metals, for example aluminum, are used only in lighter applications because they have low strength and cannot sustain the extreme compressive loads in a valve train.

Tie bar tappets use metal tie bars that connect a pair of tappets to keep the rollers aligned with the camshaft. The metal tie bars are generally made from steel having high density, thereby adding to the overall weight of the tappet and the valve train. Tie bars cannot be made too thin because they crack during operation.

Therefore, there is a need for tappets and tie bars that are strong, lightweight, and reliable.

Summary

An aspect of the invention described herein provides a method for manufacturing at least one fiber-reinforced polymer tappet, the method including: identifying at least one technical parameter of the tappet for designing and producing a tappet body blank including at least 20% fiber-reinforced polymer by volume; machining integral areas of the tappet body blank to obtain a tappet blank, and preparing a bearing surface in the tappet blank for a cup register having a 0-63 microinch Ra finish; and finishing the tappet blank to obtain the fiber- reinforced polymer tappet.

In embodiment of the method, producing the tappet body blank further includes building a one-part or a two-part tappet body blank. In some embodiments of the method, producing the tappet body blank is by at least one process selected from: contour compression molding; injection molding; over mold injection molding; and resin injection molding.

In an embodiment of the method, producing further includes manufacturing a standard FRP Billet Rod, machining the standard FRP Billet rod to obtain a machined rod, and bonding the rod with a thermoplastic or thermoset adhesive to a first part thereby obtaining the one-part body blank; or alternatively manufacturing a first part using at least one process selected from: contour compression molding, injection molding, over mold injection molding, and resin injection molding, and bonding the first part with a thermoplastic or thermoset adhesive to a second part thereby obtaining the two-part body blank.

An embodiment of the method further includes after finishing, subjecting the tappet blank to heavy metal ion implantation treatment. An embodiment of the method further includes after finishing, impregnating the tappet with sodium silicate impregnation. An embodiment of the method further includes applying a vapor deposited coating or a plasma sprayed coating on the tappet blank or the integral areas. The coating is at least one selected from: a diamond-like carbon coating, a technical ceramic coating, a metal coating, a pure molybdenum coating, and a molybdenum disulfide coating. An embodiment of the method further includes applying an electroplated coating on the tappet blank or the integral areas. The electroplated coating is a metal selected from aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, and zinc.

In an embodiment of the method, the integral areas include at least one of: bottom of the tappet, cup register of the tappet, and outside diameter of the tappet. An embodiment of the method further includes applying a painted coating to the tappet blank or the integral areas. The coating is at least one selected from: a ceramic paint coating, a metallized paint coating, a pure molybdenum paint coating, a graphite paint coating, and a molybdenum disulfide paint coating.

An embodiment of the method further includes applying an anti-friction dry film coating to the tappet blank or the integral areas. The anti-friction dry film is at least one selected from: molybdenum disulfide, tungsten disulfide, and graphite. An embodiment of the method further includes subjecting the tappet blank or the integral areas to shot peening.

In an embodiment of the method, finishing the tappet blank further includes at least one process selected from: milling, honing, grinding, turning, lapping, polishing, vibratory finishing, and electropolishing.

An aspect of the invention described herein provides a fiber-reinforced polymer tappet including a tappet blank having at least 20% fiber-reinforced polymer by volume, the tappet blank is selected from: a one-part tappet body blank or a two-part tappet body blank. In an embodiment the tappet body blank is selected from: a contour compression molded body blank; an injection molded body blank, an over mold injection molded body blank; a resin injection molded body blank; a standard FRP Billet Rod; a standard FRP Billet rod machined, and bonded with a thermoplastic or a thermoset adhesive to a first part to obtain the one part body blank; and a first part bonded with a thermoplastic or thermoset adhesive to a second part to obtain the two-part body blank.

In an embodiment of the two-part tappet body blank the first part is manufactured by at least one process selected from: contour compression molding, injection molding, over mold injection molding, and resin injection molding. An embodiment of the tappet blank further includes a Heavy Metal Ion Implantation Treatment. An embodiment of the tappet blank further includes a Sodium Silicate Impregnation. An embodiment of the tappet blank further includes a vapor deposited coating or a plasma sprayed coating of at least one material selected from: a diamond-like carbon coating, a technical ceramic coating, a metal coating, a pure molybdenum coating, and a molybdenum disulfide coating.

An embodiment of the tappet blank further includes an electroplated coating of at least one metal selected from: aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, and zinc. In some embodiments, the tappet body blank has integral areas that are machined. An embodiment of the tappet blank further includes a painted coating of at least one material selected from: a ceramic paint coating, a metallized paint coating, a pure molybdenum paint coating, a graphite paint coating, and a molybdenum disulfide paint coating. An embodiment of the tappet blank further includes an anti-friction dry film coating of at least one material selected from: molybdenum disulfide, tungsten disulfide, and graphite. An embodiment of the tappet blank further includes at least one shot- peened surface.

An aspect of the invention described herein provides a method for producing a fiber- reinforced polymer tappet blank, the method including: designing and producing a tappet body blank including at least 20% fiber-reinforced polymer by volume; machining the tappet body blank for integral parts to obtain a tappet blank; and generating a bearing surface in the tappet blank for a cup register having a 0-63 Ra finish.

In an embodiment of the method, generating the bearing surface further includes machining the tappet blank by at least one process selected from: milling, honing, grinding, turning, lapping, polishing, vibratory finishing, or electropolishing. An embodiment of the method further includes after generating, inserting and bonding a cup register insert into the cup register. In some embodiments the cup register insert is technical ceramic. In alternative embodiments the cup register is metal.

An aspect of the invention described herein provides a method for manufacturing a plastic or a fiber-reinforced polymer tie bar, the method including: producing a plastic or fiber-reinforced polymer tie bar blank by at least one process selected from: machining a plastic billet, plastic casting, injection molding, compression molding, contour compression molding, injection molding, over mold injection molding, and resin injection molding; or alternatively creating a standard FRP Billet; and machining the tie bar blank to obtain the plastic or the fiber-reinforced polymer tie bar.

In an embodiment of the method, the plastic tie bar blank includes a thermoset plastic material or a thermoplastic plastic material. An embodiment of the method after producing the tie bar blank further includes subjecting the tie bar blank to heavy metal ion implantation treatment. An embodiment of the method further includes impregnating the tie bar blank with sodium silicate impregnation. In some embodiments the method further includes applying a vapor deposited coating or a plasma sprayed coating on the tie bar blank; the coating is at least one selected from: a diamond-like carbon coating, a technical ceramic coating, a metal coating, a pure molybdenum coating, and a molybdenum disulfide coating.

An embodiment of the method further includes applying an electroplated coating on the tie bar blank; the electroplated coating is a metal selected from aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, and zinc. In some embodiments the method further includes applying a painted coating to the tie bar blank; the coating is at least one selected from: a ceramic paint coating, a metallized paint coating, a pure molybdenum paint coating, a graphite paint coating, and a molybdenum disulfide paint coating.

An embodiment of the method further includes applying an anti-friction dry film coating to the tie bar blank; the anti-friction dry film is at least one selected from: molybdenum disulfide, tungsten disulfide, and Graphite. After generating the tie bar blank, in some embodiments the method further includes subjecting the tie bar blank to shot peening. An embodiment of the method further includes finishing the tie blank by at least one process selected from: milling, honing, grinding, turning, lapping, polishing, vibratory finishing, and electropolishing.

An aspect of the invention described herein provides a plastic or fiber-reinforced polymer tie bar. In some embodiments the plastic tie bar includes a thermoset plastic material or a thermoplastic plastic material. In some embodiments the thermoset plastic or the thermoplastic plastic tie bar is selected from: a plastic billet machined tie bar, a casted plastic tie bar, an injection molded tie bar, or a compression molded tie bar.

In alternative embodiments, the fiber-reinforced polymer tie bar is selected from: a contour compression molded tie bar; an injection molded tie bar, an over mold injection molded tie bar; a resin injection molded tie bar; and a standard FRP Billet. In some embodiments the tie bar further includes a Heavy Metal Ion Implantation Treatment. In some embodiments the tie bar further includes a Sodium Silicate Impregnation. In some embodiments the tie bar further includes a vapor deposited coating or a plasma sprayed coating of at least one material selected from: a diamond-like carbon coating, a technical ceramic coating, a metal coating, a pure molybdenum coating, and a molybdenum disulfide coating.

An embodiment of the tie bar further includes an electroplated coating of at least one metal selected from: aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, and zinc. In some embodiments the tie bar further includes a a painted coating of at least one material selected from: a ceramic paint coating, a metallized paint coating, a pure molybdenum paint coating, a graphite paint coating, and a molybdenum disulfide paint coating. An embodiment of the tie bar further includes an anti-friction dry film coating of at least one material selected from: molybdenum disulfide, tungsten disulfide, and Graphite. In some embodiments of the tie bar includes at least one shot-peened surface.

Brief Description of Drawings

Figure 1 is a schematic isometric view of filament winding including: the mandrel (2) and the filaments (1) being wound around the mandrel.

Figure 2 is a schematic drawing of an isometric view of roll wrapping including: the mandrel (3), the woven laminate (4) being wrapped around the mandrel, the 90-degree laminate (5) being wrapped around the mandrel, the 45-degree laminate (6) being wrapped around the mandrel, and the zero-degree laminate (7) being wrapped around the mandrel.

Figure 3A- Figure 3B is a set of schematic drawings of a top view (Figure 3A) and a cross section (Figure 3B) of a mold for a tube including: the molded part (8), the cavity (9), the core (10), the mandrel (11), the mandrel in the top view (12), and the knife-edge areas of the core (13). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 4A- Figure 4B is a set of schematic drawings. Figure 4A is a top view and Figure 4B is a cross section of a mold design without any knife-edge areas, including: the molded part (14), the cavity (15), the core (16), the mandrel (17), and the mandrel in the top view (18). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 5 is a schematic drawing of a cross section of molded parts without any knife- edge areas, including: a rectangular cross section (19), a cross section with the parting line at the top (20), a cross section with the parting line between the center of the inner diameter and the top (21), a cross section with the parting line at the center of the inner diameter (22), a cross section with the parting line between the center of the inner diameter and the bottom (23), and a cross section with the parting line at the bottom (24).

Figure 6 is a schematic drawing of the pultrusion process, including: rovings of fiber (25), consolidation of the tows of fiber (26), a resin impregnation station (27), the resin (28), a heated die (29), a cooling die (30), pullers (31), a cutoff station (32), cutoff FRP parts (33), and a catching station (34).

Figure 7 is a schematic drawing of the injection molding process, including: plastic pellets (35), a hopper (36), an injection ram (37), the pellets being pushed and heated (38), a heater (39), the sprue (40), the molded part (41), the cavity (42), the core (43), and cooling ports (44).

Figure 8 is a schematic drawing of a front view, a cross section view, and an isometric view of an alternative compression molding process for molding a tube including: the molded part (45), the cavity (46), the mandrel (47), and the core (48). The figure depicts salient features and shows the core and cavity areas that interact with the molded part. Figure 9 is a schematic drawing of a front view and an isometric view of different types of tappets and their features, including: a flat tappet (49), a keyway tappet (50), a flat- spotted tappet (51), a pair of tie-bar tappets (52), the rounded bottom on the flat tappet (53), the key on the keyway tappet (54), the flat-spots on the flat-spotted tappet (55), and the tiebar on the pair of tie-bar tappet (56).

Figure 10 is a schematic drawing of a front view, a cross section view, and an isometric view of a one-piece contour compression molded flat tappet blank (57).

Figure 11 is a schematic drawing of a top view and a cross section view of the molding process for a one-piece contour compression molded flat tappet blank, including: the molded part (58), the cavity (59), the core (60), and the ejector pins (61). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 12 is a schematic drawing of an isometric view of an example winding jig for a flat tappet blank, including: the winding (62), the winding jig base (63), winding jig protrusions that are attached to the base (64), winding jig protrusions that are the same piece as the base (65), and the ejector plate (66).

Figure 13 is a schematic drawing of an isometric view of different fiber fabric reinforcement types, including a unidirectional fabric (67) and a plain weave woven fabric (68).

Figure 14 is a schematic drawing of an exploded front view, an isometric view, and a cross section view of a layup jig in use, including: the bulk molding compound or sheet molding compound material (69), the windings (70), the fabric laminates (71), the base (72), and the removable cavity wall (73).

Figure 15 is a schematic drawing of an exploded front view, an isometric view, and a cross section view of another layup jig in use, including: the bulk molding compound or sheet molding compound material (74), the windings (75), the fabric laminates (76), the base (77), and the ejector plate (78).

Figure 16 is a schematic drawing of an isometric view of an expanded view of the pre-molding process for a one-piece contour compression molded tappet blank, including: the bulk molding compound or sheet molding compound material (79), the windings (80), the fabric fiber laminates (81), the cavity (82), and the core (83). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 17 is a schematic drawing of a top view and a cross section view of the molding process for a one-piece injection molded tappet blank, including: the molded part (84), the cavity (85), the core (86), the sprue (87), and the ejector pins (88). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 18 is a schematic drawing of an isometric view of an expanded pre-molding process of a one-piece over mold injection molded tappet blank, including: the windings (89), the fabric fiber laminates (90), the cavity (91), the core (92), and the sprue (93). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 19 is a schematic drawing of an isometric view of an expanded pre-molding process for a one-piece resin injected and over molded tappet blank, including: the chopped fiber (94), the windings (95), the fabric fiber laminates (96), the cavity (97), the core (98), and the sprue (99). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 20 is a schematic drawing of a front view and a cross-section view of two- piece flat tappets with different connections, including: a tappet with the upper and lower body connected with a lip and molded together with undercuts (100), a tappet with the upper and lower body connected without a lip and molded together with undercuts (101), a tappet with the upper and lower body connected with a lip and dowel pin (102), a tappet with the upper and lower body connected with a lip and a flat spot (103), a tappet with the upper and lower body connected with a lip and threads (104), a tappet with the upper and lower body connected with a lip and a side pin (105), a tappet with the upper and lower body connected with a lip and a vertical key (106), and a tappet with the upper and lower body connected with no lip and dowel pins (107).

Figure 21 is a schematic drawing of a front view, a cross section view, and an isometric view of a two-piece contour compression molded tappet blank, including: the lower body (108), the upper body (109), a domed shape (110), a horizontal undercut (111), and angled undercuts (112).

Figure 22 is a schematic drawing of a top view and a cross section view of the molding process for a two-piece contour compression molded tappet blank, including: the lower body of the molded part (113), the upper body of the molded part (114), the cavity (115), the core (116), and the ejector pins (117). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 23 is a schematic drawing of a top view and a cross section view of the molding process for a two-piece injection molded tappet blank, including: the lower body (118), the upper body (119), the cavity (120), the core (121), the sprue (122), and the ejector pins (123). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 24 is a schematic drawing of a front view and a cross section view of flat tappets with different cups, including: a one-piece tappet with a separate cup piece (124), a one-piece tappet with the cup directly machined into the body of the part (125), a two-piece tappet with a separate cup piece on the upper body (126), a two-piece tappet with a separate cup piece on a stem of the lower body (127), a two-piece tappet with the cup directly machined into the upper body (128), a two-piece tappet with the cup directly machined into a stem of the lower body (129).

Figure 25 is a schematic drawing of a front view and a cross section view of an exemplar roller tappet and its parts, including: the roller wheel (130), axle (131), axle- register-hole (132), and wheel space profile (133).

Figure 26 is a schematic drawing of a front view, a cross section view, and an isometric view of exemplar one-piece roller tappet body blanks, including: a roller tappet body blank that is contour compression molded with the wheel space profile molded in (134), a roller tappet body blank that is injection molded with the wheel space profile molded in

(135), and a roller tappet body blank that does not have the wheel space profile molded in

(136).

Figure 27 is a schematic drawing of a front view, a cross section view, and an isometric view of exemplar two-piece roller tappet blanks, including: a contour compression molded two-piece roller tappet blank with a thick lower body already containing the axle- register-hole and wheel space profile (137), a contour compression molded two-piece roller tappet blank with a shelled lower body already containing the axle-register-hole and wheel space profile (138), an injection molded two-piece roller tappet blank with a thick lower body already containing the axle-register-hole and wheel space profile (139), and an injection molded two-piece roller tappet blank with a shelled lower body already containing the axle- register-hole and wheel space profile (140).

Figure 28 is a schematic drawing of a top view and a cross section view of the molding process for a two-piece contour compression molded roller tappet blank and two- piece injection molded roller tappet blanks that both already have their axle-wheel-profiles and wheel space profiles made before molding, including: the lower body for contour compression molding (141), the contour compression molded upper body (142), the compression mold cavity (143), the compression mold core (144), the compression mold ejector pins (145), the lower body for injection molding (146), the injection molded upper body (147), the injection mold cavity (148), the injection mold core (149), the injection mold sprue (150), and the injection mold ejector pins (151). The figure depicts salient features and shows the core and cavity areas that interact with the molded part.

Figure 29 is a schematic drawing of a front view and a cross section view of exemplar two-piece roller tappet blanks that have their axle-register hole and wheel space profile machined into the blank after either molding or bonding the upper and lower bodies together, including: a two-piece roller tappet blank that has the axle-register-hole and wheel space profile shared in the lower and upper body (152), a two-piece roller tappet blank that has the axle-register-hole shared in the lower and upper body and the wheel space profile only in the lower body (153), a two-piece roller tappet blank that has the axle -register-hole only in the lower body and the wheel space profile shared in the lower and upper body (154), and a two- piece roller tappet blank that has the axle-register-hole and wheel space profile only in the lower body (155).

Figure 30 is a schematic drawing of a front view and an isometric view of roller tappet wheels, including a full wheel (156) and a cutout wheel (157).

Figure 31 is a schematic drawing of a side view and a cross section view of exemplar roller tappets with different methods to connect the axles to the wheels, including a roller tappet with the wheel and axle directly running on each other (158), a roller tappet with a needle bearing between the axle and wheels (159), and a roller tappet with a bushing between the axle and wheels (160).

Figure 32 is a schematic drawing of a side view and a cross section view of exemplar roller tappets with different methods to connect the axles to the main bodies of the tappet, including: a roller tappet that uses pins for connecting the axle and body (161), a roller tappet that uses set screws for connecting the axle and body (162), a roller tappet that uses a thermoset or thermoplastic adhesive for connecting the axle and body (163), the pins (164), the set screws (165), and the thermoset or thermoplastic adhesive (166).

Figure 33 is a schematic drawing of a front view, a cross section view, and an isometric view of a flat-spotted tappet, including: the flat-spotted tappet (167), the lifted area around the tappet (168), and the flat spots (169).

Figure 34 is a schematic drawing of a front view and an isometric view of exemplar tie bar tappet pairs, including: the lifted area around the tappets (170), a tie bar tappet pair that uses a rivet to connect the tappet bodies to the tie bar (171), and a tie bar tappet pair that uses bolts and nuts to connect the tappet bodies to the tie bar (172).

Figure 35 is a schematic drawing of a top view and an isometric view of two different tie bars, including: a straight tie bar (173), a bent tie bar (174), the holes in the tie bars (175), and slots in the tie bars (176).

Figure 36 is a schematic drawing of a front view, cross section view, and an isometric view of different exemplar keyway tappets, including: the lifted area around the tappets (177), a tappet with a key as the same piece as the body of the tappet (178), a tappet that has an inserted key (179), the key that is the same piece as the body (180), the inserted key (181), and the extra material around the inserted key (182).

Detailed Description

New methods are provided for designing and producing fiber reinforced polymer tappets which are light weight, high strength, and have high stiffness. These qualities are desirable for tappets in high performance applications.

Lightweight tappets allow engines to have weaker valve springs to keep the tappets in contact with the camshaft lobe. The weaker valve springs reduce the amount of deflection in the valve train and decrease wear in parts during engine cycles. Lighter tappets also reduce the amount of energy and fuel consumed for accelerating engines. Therefore, the use of lightweight tappets leads to greater power, better fuel economy, and reduced greenhouse gases from engines. Definitions:

Technical Ceramics are advanced ceramics or engineered ceramics. They are typically oxides, carbides, borides, nitrides, or silicides. Technical ceramics typically exhibit high hardness and substantially high compressive strengths. However, technical ceramics tend to be brittle and have substantially low tensile/shear strengths. Examples of technical ceramics are AI2O3 (Aluminum Oxide), SiC (Silicon Carbide), WC (Tungsten Carbide), Shapal (a hybrid aluminum nitride ceramic), Macor (a machinable glass-ceramic), BN (Boron Nitride), AIN (Aluminum Nitride), B4C (Boron Carbide), Si N4 (Silicon Nitride), ZrO2 (Zirconium Oxide), TiN (Titanium Nitride), ZrN (Zirconium Nitride), CrN (Chromium Nitride), TiCN (Titanium Carbonotride), CrCN (Chromium Carbono tride), TiCrN (Titanium Chromium Nitride), AlTiN (Aluminum Titanium Nitride), and AlCrN (Aluminum Chromium Nitride).

Thermoplastics are polymers that can be melted, cooled, and recast. Examples of thermoplastics include polytetrafluoroethylene, polyvinylidene fluoride, polycarbonate, polyoxymethylene, nylon, polyamide-imide (polyamide-imides are thermoplastic or thermoset depending on the specific material), and polyether ether ketone.

Thermosets are polymers which are permanently cured by thermal or chemical activation. Examples of thermosets include polyester, epoxy, phenolic, vinyl ester, bismaleimide, polyurea, polyurethane, silicone, fluoropolymer, polyamide, and polyamideimide (polyamide-imides are thermoplastic or thermoset depending on the specific material).

Fiber- Reinforced Polymer (FRP) is a composite material that consists of fibers embedded within a polymer matrix material (which is either a thermoplastic or thermoset resin). These composites normally have a substantially high strength-to-weight ratio and stiffness-to- weight ratio. Examples of the fibers include carbon, boron, silica, quartz, fiberglass, aramid, Kevlar, and basalt.

Fiber Orientation of the tappet refers to the way fibers within FRP material are aligned during different manufacturing methods, such as a zero-degree, a 45 -degree, and a 90-degree direction. A zero-degree direction corresponds to the axial direction of the tappet body. A 90-degree direction corresponds to the perpendicular of the axial direction of the tappet body. A 45-degree direction corresponds to a 45-degree offset from the axial direction of the tappet body. Therefore, if a fiber reinforced polymer (FRP) tappet body is manufactured with laminates oriented in the zero-degree direction, the 45-degree direction, and the 90-degree direction, the fibers of the zero-degree directional laminates are oriented in the lengthwise direction, the fibers of the 90-degree directional laminates are oriented as wrapping around the circumference of the tappet body, and the 45 -degree directional laminates fibers are oriented helically, wrapping around the circumference and going up the length of the tappet body at the same time.

Filament Winding is a process in which tows of fiber that are under tension are fed through resin and wound around a rotating mandrel (which is generally made of steel). This process is illustrated in Figure 1 having the mandrel (2) and the tow being wound around the mandrel (1). The winding creates geometric patterns which are used to optimize strength in the necessary orientation. Fibers oriented in the zero-degree direction provide axial bending, tensile, and compressive strength, fibers oriented in the 45 -degree direction provide torquing strength, and fibers oriented in the 90-degree direction provide radial crushing strength. A tappet experiences compressive forces, therefore, fiber orientations are generally in 0-degree direction. Further, some fibers are oriented in other directions (45 -degree and 90-degree) to mitigate radial resin expansion during compression. After winding, the mandrel/wound tow assembly is wrapped in a plastic wrap, heated, and cured. The plastic wrap contracts under heat, creating the necessary compaction in the part. The above process is commonly used to create a composite part, such that the mandrel can be removed from the composite part and reused. In some embodiments, instead of using a removable/reusable steel mandrel, a composite part is used as the “mandrel”, and the filaments are permanent reinforcements that are stuck to the composite part. Therefore, filament winding is used to provide additional support and strength to other FRP structures.

Roll Wrapping is a process in which layers of FRP laminates are wrapped on a mandrel (generally a steel mandrel) to create tubes. This process is illustrated in Figure 2, in which the laminates are being wrapped around the mandrel (4, 5, 6, and 7). Different orientations and types of laminates are roll wrapped. For example, a woven laminate (4), a 90-degree laminate (5), a 45-degree laminate (6), and a zero-degree laminate (7). Similar to filament winding, fibers oriented in the zero-degree direction provide axial bending and compressive strength, fibers oriented in the 45-degree direction provide torquing strength, and fibers oriented in the 90-degree direction provide crushing strength. Fiber orientations in a tappet generally are in the 0-degree direction to combat compressive forces and a portion of fibers are oriented in other directions. Similar to the process of filament winding, the mandrel/laminate assembly is wrapped in plastic for compaction, heated, and cured. This process is commonly used to create a composite part with a reusable mandrel. However, in certain embodiments, other FRP structures act as the “mandrel” and the wrapped laminates provide additional support, strength, and permanent reinforcements to the other FRP structure.

Compression Molding is a process used to produce parts, in which FRP material is placed into a mold and compressed under pressure with a press. After a set amount of time, the pressure is released, the mold is opened, and the part is ejected. If the FRP material is thermoset based, the material is optionally preheated before molding and the temperature of the mold has to be hot enough to cure the material. However, if the material is thermoplastic based, it must be preheated to a temperature above its glass transition temperature (Tg) to allow the material to soften enough for molding. The mold temperature is optimally set below the melting temperature ™ of the material such that the part is ejected quickly. However, with thermoplastic compression molding, the mold temperature sometimes must be set above Tm for the material to adequately fill the mold cavity. For thermoplastic compression molding, the mold must be cooled to a temperature less than Tm before ejection, adding cycle time and costs. Generally, the FRP material used in compression molding consists of a bulk molding compound (BMC) or sheet molding compound (SMC) with discontinuous chopped fiber. BMCs are generally processed in bulk form and are not pre-formed before molding. However, SMCs are processed into a sheet before molding, meaning SMCs typically have a lower compression ratio (the ratio between the volume of material before molding and the volume of material after molding). If continuous fiber laminates are used with compression molding, extra attention and time is needed to ensure that the laminates are placed in their exact position and that orientation is correct.

Contour Compression Molding is a method of compression molding a shape which is close to near net the geometry of the final part. The contour compression molded part in certain embodiments requires additional steps, such as post-molding machining to reach the final geometry of the part. However, most profile features from the contour compression molded part are generally not altered after molding.

Compression Molding a Tube: A tube shape cannot be compression molded directly as shown in Figure 3 because the core of the mold (10) creates very thin knife-edge areas (13). These knife-edge areas are almost zero thickness and hence would break upon machining the mold. Further, even if the knife-edge areas do not break during machining, they would break off due to the high pressures that are experienced during molding by the cavity and core surfaces. Therefore, to compression mold a tube, a molded part that does not create a knife-edge area has to be molded first. As seen in Figure 4, the molded part (14) is flat at the top at the parting line between the cavity (15) and the core (16) thereby obtaining a compression molded tube without any knife-edge areas. Figure 5 illustrates exemplary cross sections for molding a tube without creating knife edge areas such as: a rectangular cross section (19), a cross section having the parting line at the top (20), a cross section having the parting line between the center of the inner diameter and the top (21), a cross section having the parting line at the center of the inner diameter (22), a cross section having the parting line between the center of the inner diameter and the bottom (23), and a cross section having the parting line at the bottom (24). In the cross section having the parting line at the center of the inner diameter (22), the flange on either side is removed by handwork. Tubes compression molded by the other designs (19, 20, 21, 23, and 24) require secondary machining after molding to create the outer, circular profile of the tube. Therefore, in certain embodiments, compression molding a tube includes an additional step of creating the outer profile of the tube by handwork or machining. To create the internal hole of the tube, a mandrel has to be inserted as seen in Figure 3 and Figure 4, in which the mandrel (11, 12, 17, and 18) is inserted into the cavity of the mold before the molding material is inserted. After inserting the mandrel, the molding material is inserted, and the mold is closed under pressure for a set time. The mold is opened, the mandrel is removed from the mold and the part is ejected. The mandrel is reusable.

Compression Molding a Rod: The process for compression molding a rod is similar to compression molding a tube. However, for a rod a mandrel is not used, resulting in a solid molded part without a tubular cavity. Similar to the process of compression molding a tube, compression molding a rod requires an additional step of creating the outer profile of the rod by handwork or machining.

Pultrusion is a process used to produce continuous fiber-reinforced polymers with a constant cross section. In certain embodiments, the FRP being pultruded is shaped as a rod or a tube. The process of pultrusion is illustrated in Figure 6. Tows from the rovings of fiber reinforcements are pulled and consolidated (25 and 26) and fed into a resin impregnation station (27), in which the fiber reinforcement is impregnated with a thermoset or thermoplastic resin (28). The resin-impregnated fiber is then pulled through a heated shaping die (29), which for a rod or a tube would be either an open hole for creating the outer diameter of a rod profile or an open hole with a mandrel for creating the internal diameter of a tube. If the FRP is thermoset based, the heated pultrusion die causes the resin to cure and solidify. If the FRP is thermoplastic based, the heated pultrusion die is used to fuse the different impregnated fiber tows together, and a cooling die (30) is used to solidify the FRP. The solidified FRP is then clamped and pulled out by pullers (31). The solidified FRP is then cut at the right length with saws at the cutoff station (32). The cutoff FRP parts (33) then fall into a catching station (34).

Injection molding is a process used to produce molded products, in which plastic material is injected into a mold, solidified, and ejected. The process of injection molding thermoplastic materials is illustrated in Figure 7. Pellets of plastic material (35) are inserted into a hopper (36). An injection ram (37), which generally has the shape of a screw, turns to push the plastic forward. The plastic being pushed forward (38) is heated by heaters (39) and pushed through the sprue, (40) which is a narrow opening for the plastic to flow through. The plastic is molded into the shape of the molded part (41) by being injected into the cavity (42) and the core (43). In thermoplastic injection molding, cooling ports (44) which typically run water are present to solidify the part before the cavity (42) and core (43) are separated and the part is ejected. In thermoset injection molding, there are no heaters (39), and the plastic material (35) is inserted cold, into the heated cavity (42) and core (43). Further, instead of cooling ports (44), thermoset injection molding includes heaters. The heaters in the cavity (42) and core (43) of the mold cure the thermoset material coming from the sprue (40) and solidify the part before ejection. The thermoset or thermoplastic material being injected is generally an unreinforced polymer. Pellets with fiber reinforcement are used to injection mold FRP material. However, it is generally difficult to achieve long fiber lengths because the fibers break in the process of getting pushed by the injection ram (37) and through the sprue (40).

Over mold injection molding is a variant of injection molding in which the cavity of the mold is preloaded with material before the plastic material is injected. Over mold injection molding is used to add other materials, such as metals, technical ceramics, or FRPs, to the final part. Because the plastic material coming from the sprue is injected at high pressures and the other materials preloaded into the cavity have undercuts, over mold injection molding creates strong bonds.

Resin injection molding is a variant of injection molding in which the cavity of the mold is preloaded with dry fiber material before the plastic material is injected. Resin injection molding create stronger parts compared to with typical injection molding because resin injection molding allows for long fibers to be preloaded into the mold before the resin is injected. In certain embodiments, resin injection molding is built over mold injection molding, in which other materials, such as metals, technical ceramics, or FRPs, are inserted into the mold with the dry fiber material before the plastic is injected.

Vertically Compression Molding a Tube: A tube shape is compression molded in an alternative method as illustrated in Figure 8, in which the molded part (45) is molded between the cavity (46) and core (48). The mandrel (47) is vertical, and oriented in the direction of the cavity and core compression. The mandrel (47) and the cavity (46) are the same pieces or alternatively the mandrel (47) is attached to the cavity (46) by fasteners as a pin. Vertical compression molding process is generally used for tubes that have a relatively low length-to- diameter ratio.

Vertically compression molding a rod is a process which is similar to vertically compression molding a tube. However, a mandrel is not used for compression molding a rod thereby resulting in a solid molded part without a tubular cavity.

Sodium silicate solution is a solution of silica and sodium oxide dissolved in water. The sodium silicate has a weight ratio of 3.22 (SiO2:Na2O), which breaks down as about 28.7% silica (SiO2) to about 8.9% sodium oxide (Na20) resulting in a solution which is approximately 37.5% sodium silicate by weight in water.

Sodium silicate impregnation is a process that introduces sodium silicate as a filling material into the open pores of the material being treated. The process eliminates or greatly reduces the undesirable hygroscopic effects of porosity in the parts being treated. Parts being impregnated are first treated with a sodium silicate solution containing both potassium dichromate, and chromic acid(s). The solution fills the porosity of the parts, and the parts are then thoroughly washed in cold water, thereby leaving the solution in the pores of the substrate. The parts are placed in the autoclave to remove the air from the pores by applying vacuum for a specific period of time, usually about 20 minutes at 26”Hg. A heated sodium silicate solution is introduced into the vacuum autoclave, the parts are covered with the solution and pressure is applied to increase from negative pressure to positive pressure. The standard temperature is maintained at about 95 °C to 100 °C and the pressure is about 60 lbs. to 85 lbs. per square inch. The pressure is maintained for about 8 hours and then released. The parts are subsequently removed from the autoclave and solution, then thoroughly washed in cold water. The parts are then placed into a low temperature oven at about 100 °C for at least one hour. The specific gravity of the sodium silicate solution used is maintained by addition of water intermittently as the solution tends to evaporate upon heating to operating temperatures.

Heavy Metal Ion Implantation (HMII) is a process that bombards heavy metal ion particles, such as but not limited to Uranium, Molybdenum, Titanium, Tungsten, or Chromium, deep into the molecular structure of part surfaces. The process of HMII increases the microhardness of the surface and fatigue life of the part. In addition, the implantation treatment creates a surface finish which is smoother compared to typical industrial processes, such as lapping or vibratory finishing. The heavy metal ions are typically accelerated to about 400 miles per second before colliding with the part being treated. The process typically occurs in a vacuum of 1 billionth atmospheric pressure to prevent contamination from air molecules or any disruption of the path for the heavy metal ions to flow. Because the bombarding ions add energy to the substrate, and heat cannot dissipate well in vacuum, parts being treated typically need a heat soak system to prevent the temperature of the substrate from rising above their glass transition temperature.

Shot Peening is a process in which particles (typically round metallic, glass, or ceramic particles) strike the surface of the part being treated. The striking of these particles creates plastic deformation on the part which results in a residual compressive stress layer. This residual compressive stress improves the mechanical properties and fatigue life of the given substrate because the residual compressive stresses mitigate the creation and propagation of microcracks.

Vapor Deposited Coating is a process that applies high-performance solid material coatings onto a given substrate. The two main processes are Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD). In PVD, the material to be coated is vaporized and condensed into a thin film on the substrate being coated, either by sputtering or evaporation. In CVD, the substrate being coated is exposed to volatile precursors that react on the surface of the substrate to produce the desired deposit. Examples of vapor deposited coatings are as follows:

1. DLC (Diamond-Like Carbon) is a coating that consists of diamonds suspended in a graphite matrix. The coating has a hardness of about 1600 to about 2000 Hv and a coefficient of friction of 0.05-0.10. A higher concentration of diamonds increases both the hardness and the coefficient of friction.

2. MoS2 (Molybdenum Disulfide) is a very thin anti-friction coating that reflects the hardness of the substrate underneath. The coating generally has a 0.01-0.03 coefficient of friction and is typically applied directly to the substrate or to a hard ceramic coating.

3. TiN (Titanium Nitride), ZrN (Zirconium Nitride), CrN (Chromium Nitride), TiCN (Titanium Carbonotride), CrCN (Chromium Carbono tride), TiCrN (Titanium Chromium Nitride), AlTiN (Aluminum Titanium Nitride), and AlCrN (Aluminum Chromium Nitride) are hard technical ceramic coatings that have a hardness of over 2000 Hv. These coatings are generally followed by a coating of MoS2 because of their high coefficient of friction.

4. Aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, and zinc are examples of metal coatings. The metal coatings are generally used to create a conductive surface that is increased in thickness by electroplating.

Electroplating is a process that uses controlled electrolysis (using electric current to cause a non-spontaneous chemical reaction) to apply a desired metal coating from an anode to a cathode. Examples of metals that are electroplated include aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, and zinc. The anode is the metal part which is used to create the plating, and the cathode is the part being coated by the anode material. Both the anode and the cathode are placed in a bath with electrolyte chemicals and are exposed to an electric charge. The electric charge causes anions (negatively charged ions) to move to the anode and cations (positively charged ions) to move to the cathode, which covers the cathode part in a metal coating. This creates a thin shell of metal on the cathode part. To electroplate non-conductive substrates, such as most FRP materials, the parts must first be made electrically conductive. This is typically achieved by adding a thin layer of metal through an electroless plating process, such as PVD coating. For the embodiments described herein, electroplating FRP material includes an initial step of electroless plating to create a conductive surface.

Plasma spray coating is a process where a substrate is sprayed with molten or semimolten material to create a hard coating. The coatings are applied in a high temperature process in which the powdered coating material is heated through an extremely hot plasma flame (over 20,000 °F) and accelerated toward the substrate. The coating material then cools and forms a hard coating. Plasma spray coatings are generally used to protect the substrate from oxidization, to create a thermal barrier coating, to create an anti-friction surface, and/or to create an anti-wear surface. Generally for plasma spray coating FRP materials, the materials are pre-coated with a bond coat such as nickel-aluminide. The bond material provides a more conductive and harder surface which enables bonding with a secondary coat. For embodiments described herein, plasma spray coating FRP material includes an initial step of applying a bond coat to create a conductive and harder surface.

Dry film coatings create anti-friction surfaces that maintain a low coefficient of friction even under dry conditions (without liquids or oils). Molybdenum Disulfide (MoS2), Tungsten Disulfide (WS2), and Graphite are common materials used for dry film coatings. Dry film coatings are typically applied by brushing, spraying, or dipping, in which the dry film coating material (MoS2, WS2, or Graphite) is added to resins and binders that are then coated on the part. The resins and binders generally require either a thermal, chemical, or air cure. Dry film coatings are also applied by impingement coating, in which the coating is applied in an extremely thin layer and does not require a cure.

Valve train deflection is the amount of valve lift that is lost due to the deflection of parts such as tappets, pushrods, and rockers.

Turning is a machining process in which material is removed from a rotating workpiece by a cutting tool. This process is typically performed on a lathe and allows for the creation of high precision, and rotationally symmetric parts. Thermoset adhesives are adhesives made from a thermoset resin. The adhesives are supplied in a pre-cured state, to be applied to the workpiece for bonding and curing. In certain embodiments, adhesives cure chemically, in which exposure to air or a chemical reactor result in curing. Adhesives cured with a chemical reactor generally include two components that are mixed before being applied to the workpiece and cured. Certain adhesives cure thermally, in which heat is used to cure the adhesive. Common examples of thermosetting adhesives are JB Weld and Loctite.

Thermoplastic adhesives are adhesives made from a thermoplastic resin. Thermoplastic adhesives typically consist of resins that are preheated to near or above their melting temperature before they are applied to the workpiece. The workpiece is bonded, and the resin is then allowed to cool and harden. Thermoplastic adhesives are commonly based on Ethylene Vinyl Acetate (EVA).

Standard billet composite machining is a process used to manufacture composite parts in which a Standard FRP billet is machined down to a desired shape and size. The machining is performed by milling, turning, and grinding, or by performing a combination of the processes.

Standard FRP billets are billets made of FRP material which are later machined into further shapes. The billets generally have a rectangular geometry (sheets) or circular geometry (rods or tubes). A Standard FRP billet is manufactured by any of the following methods:

1. Resin Transfer Molding (RTM) a Standard FRP billet: In this process, dry fibers are placed into a mold, which is then filled with resin and heated to help the resin cure. Conventional RTM typically is performed at pressures less than 40 bar. RTM directly molds sheet and rod shapes and in some embodiments includes creating a sheet and then machining rod shapes from the sheet.

2. High Pressure Resin Transfer Molding (HPRTM) a Standard FRP billet: In this process, pressures of up to 200 bar are used during the molding process to increase efficiency and cycle times are as short as a few minutes for smaller parts. Further, during the HPRTM process, the mold is typically a closed mold which is not fully compressed at the time the resin is injected thereby allowing excess resin to flow in the mold. The mold is then compressed with a press to squeeze out the excess resin, allowing for higher molding efficiencies, higher fiber-to-resin ratios, and better mechanical properties compared to conventional RTM. This process directly molds sheet and rod shapes. However, HPRTM includes creating a sheet and then machining rod shapes from the sheet. Vacuum Assisted Resin Transfer Molding (VARTM) a Standard FRP billet: It is a method of creating FRP parts in which dry fibers are placed into a mold, similar to the mold used in RTM. In VARTM, the resin flow is assisted by a vacuum. An advantage of VARTM is having cheaper equipment costs and high fiber-to-resin ratios compared to conventional RTM. This process directly molds sheet and rod shapes and in alternative embodiments creates a sheet and then rod shapes are machined from the sheet. Compression Molding a Standard FRP billet: It is a method of creating FRP parts in which material is placed into a mold, compressed, and ejected. This process directly molds rod shapes and in some embodiments uses compression molding to create a sheet and then rod shapes are machined from the sheet Pultruding a Standard FRP billet: It is a method of creating FRP parts with a constant cross section in which tows of fiber are consolidated, impregnated with resin, solidified, and then cut. This process directly molds sheet and rod cross sections and in some embodiments uses pultrusion to create a sheet and then rod shapes are machined from the sheet. Injection Molding a Standard FRP billet: It is a method of creating FRP parts in which material is injected into a mold, solidified, and ejected. This process directly molds sheet and rod shapes and in some embodiments uses injection molding to create a sheet and then rod shapes are machined from the sheet. Vacuum Bagging a Standard FRP billet: It is a method of creating FRP parts in which the material is placed on a mold tool, covered with a ply (which is used to improve the surface finish), and covered with a breather fabric which absorbs extra resin. The system is then placed in a vacuum bag, which is used to remove the air and mold the part. Vacuum bagging removes excess air and humidity during the curing process thereby allowing a high fiber-to-resin ratio, increasing the mechanical properties, and decreasing the impurities of the FRP part. In addition, the process of vacuum bagging typically utilizes very low setup and tooling costs. This process directly molds sheet and rod shapes an in some embodiments uses vacuum bagging to create a sheet and then rod shapes are machined from the sheet.

8. Hand Laying Up a Standard FRP billet: It is a method of creating FRP parts in which fibers that are unidirectional, woven, knitted, stitched, chopped, or bonded, are placed in a mold, and reinforced with resin by a brush. Among the various methods described herein, this process typically has lowest setup and tooling costs. However, the process is very labor intensive and often produces parts that have to be discarded. This process directly molds sheet and rod shapes and in some embodiments uses hand layups to create a sheet and then rod shapes are machined from the sheet. . Autoclave manufacturing a Standard FRP billet refers to a method of creating FRP parts in which plies of FRP are placed in a mold and spot- welded together, then vacuum bagged and placed in an autoclave. The plies are subjected to high pressure and temperatures to cure during the autoclaving process, which directly molds sheet and rod shapes. In certain embodiments autoclave manufacturing is used to create a sheet and then rod shapes are machined from the sheet.

10. Pure roll wrapping a Standard FRP billet: It is a method of creating FRP Billets in which FRP laminates are roll wrapped around a removable mandrel, wrapped in plastic wrap, and cured. This process creates tube shapes.

11. Pure filament winding a Standard FRP billet: It is a method of creating FRP billets in which FRP tows are filament wound around a removable mandrel, wrapped in plastic wrap, and cured. This process creates tube shapes.

12. Reinforcement roll wrapping a Standard FRP billet: It is a method of creating FRP billets in which one of the methods described herein (RTM, HPRTM, VARTM, Compression Molding, Pultrusion, Injection Molding, Vacuum Bagging, Hand Laying Up, Autoclave Manufacturing, Pure Roll Wrapping, and Pure Filament Winding) is used to fabricate a billet core. After the core is fabricated, it is roll wrapped with FRP laminates, with the core functioning as a “mandrel,” and roll wrapping reinforces another FRP part.

13. Reinforcement filament winding a Standard FRP billet: It is a method of creating FRP billets in which one of the above methods described herein (RTM, HPRTM, VARTM, Compression Molding, Pultrusion, Injection Molding, Vacuum Bagging, Hand Laying Up, Autoclave Manufacturing, Pure Roll Wrapping, and Pure Filament Winding) is used to create a billet core. After the core is created, the core is filament wound with FRP tows. The core functions as the “mandrel,” and the filament winding reinforces another FRP part.

14. Combination of roll wrapping and filament winding on a Standard FRP billet: It is a method of creating FRP billets in which one of the methods described herein (RTM, HPRTM, VARTM, Compression Molding, Pultrusion, Injection Molding, Vacuum Bagging, Hand Laying Up, Autoclave Manufacturing, Pure Roll Wrapping, and Pure Filament Winding) is used to manufacture a billet core. After the core is manufactured, it is either filament wound with FRP tows and then roll wrapped with FRP laminates, or roll wrapped with FRP laminates and then filament wound with FRP tows.

Types of tappets:

Different types of tappets are illustrated in Figure 9. Flat tappets (49) are simple parts with the basic geometry to transfer rotational movement from the camshaft into linear movement of the pushrod. In certain embodiments, flat tappets have flat or rounded bottoms (53) that slide on top of the eccentric camshaft lobe. Flat tappets are cheap and easy to manufacture, however, flat tappets cannot manage aggressive camshaft lobes compared to roller tappets.

Roller tappets, unlike flat tappets, have a roller at the bottom that glides over the camshaft, allowing for more aggressive camshaft lobe profiles. To roll over the camshaft lobe, the wheel must always be aligned with the lobe. Three methods are used to keep the wheel aligned: keyways, flat spots, and tie bars. Keyway tappets (50) have a key (54) on the OD that slides into a dedicated slot that keeps the part aligned. The tappet bores either have a slot directly machined into them, or they are enlarged to fit a tappet bushing that has a slot for the key.

Flat-spotted tappets (51), which are not the same as flat tappets, have a flat spot (55) at the top of the tappet that aligns with another part added to the tappet bore, such as a tappet tray or “dog bone.” Tappet trays are common in Chevrolet engines and are additional parts that “grab” the top of multiple flat-spotted tappets which keeps the assembly aligned. “Dog bones” are metallic plates that are bolted to the engine block and have flats that locate on corresponding flats on the tappet body.

Tie-bar tappets (52) come in pairs that are connected at the top by a tie bar (56). Although the extra material of the tie bar adds extra transient mass to the valve train, maintenance on tie bar tappets is easier.

Benefits of using FRP tappets:

The utilization of FRP tappets has many benefits for an engine, specifically: quicker and easier acceleration (which leads to higher fuel efficiency and reduced greenhouse gas emissions), better valve train stability, less wear on other components, a reduction in harmful valve train harmonics, and more accurate valve timing (which also contributes to higher fuel efficiency and reduced greenhouse gas emissions).

The overall stiffness of FRP tappets is about equivalent to that of steel or aluminum tappets. Advantageously, the FRP tappets weigh much less compared to steel or aluminum tappets. In certain embodiments, a replacement FRP tappet is at least 50% lighter compared to an incumbent steel tappet. The reduction in weight allows for much quicker and easier acceleration because much less energy is spent by the engine to accelerate the transient motion of the tappet. The quicker and easier acceleration results in an engine that spends less fuel to achieve the same speed, and thereby reduces greenhouse gas emissions. The reduced weight also leads to better valve train stability because less mass needs to be accelerated and decelerated every time a valve opens, reducing the momentum of the valve train. The reduction in momentum also reduces the force and stress that other components (such as the pushrod, fulcrum rocker, and valve spring) experience, reducing wear and increasing the part life of these other components. In addition, because FRP is a much different material compared to the metal valve train parts that the tappet is in contact with, it has a different resonance frequency and stops the harmful harmonic effects experienced in a sole metal valve train.

The utilization of FRP tappets also allows for more accurate valve timing. A common issue in typical steel tappets is that upon an engine reaching a higher speed and engine/camshaft RPM, valve springs must be bigger and stronger to stop the momentum of the heavy steel tappet. However, valve springs which are larger, increase the force on the tappet, causing more deflection of the tappet and less efficient valve timing. Therefore, the tappet must be enlarged, requiring an even larger valve spring, creating a feedback loop that limits the performance possible with steel tappets. In certain cases, steel tappets are substituted with aluminum. However, aluminum is too weak for high performance applications and is much less stiff than steel, leading to the similar problems during high speeds.

FRP tappets, which have a much higher stiffness to weight ratio (also known as specific stiffness) compared to both steel and aluminum, break this cycle. A heavy steel or aluminum tappet replaced with a much lighter FRP tappet, reduces the valve spring pressure. Therefore, tappet deflection is reduced, and as a result valve train deflection is also reduced more than ever possible with steel or aluminum. The reduced valve train deflection allows for the valve timing to follow the dictates of the camshaft design much more accurately, increasing efficiency because the valves open closer to the intended time during every combustion cycle. The increased efficiency results in a reduction in greenhouse gas emissions.

Fiber reinforced polymer (FRP) flat tappets:

A first manufacturing step for FRP flat tappets is identifying the technical parameters of the tappets sought to be produced which includes finding the body OD and cup ID. Identifying a correct body OD achieves the correct clearance between the tappet bore and the outer diameter of the tappet, minimizing the ability of the tappet to twist within the bore and reduces the leaking of oil through the bore. The correct cup ID is necessary to ensure an optimal contact surface between the pushrod and tappet. After identifying the technical parameters of the flat tappets to be produced, tappet body blanks are manufactured. The tappet body blanks are either one-piece or two-piece components that consist of at least 20% FRP (by volume). After the tappet body blanks are manufactured, secondary processes are used to turn the tappet body blanks into the final tappets.

Manufacturing a one-piece FRP flat tappet body blank:

A one-piece tappet body blank is manufactured with contour compression molding. The molded part is illustrated in Figure 10, which shows a one-piece contour compression molded tappet blank (57).

The standard molding process for creating a one-piece tappet body blank is shown in Figure 11. The molded part (58) is compression molded from Bulk Molding Compounds (BMC) or Sheet Molding Compounds (SMC) between the cavity (59) and the core (60). After the BMC or SMC material is solidified, the one-piece tappet body blank is ejected by the ejector pins of the mold (61).

FRP windings add reinforcement to the molded one-piece tappet body blank. The process of making the windings is illustrated in Figure 12. The winding (62) consists of FRP tows which are wound on a winding jig. The winding jig base (63) has winding jig protrusions that are attached to the base (64) and/or winding jig protrusions that are the same piece as the base (65). These winding jig protrusions that are the same piece as the base (65) are generally machined into the base (63) as one part. The winding (62) is wound on these different winding jig protrusions in any order, and in any thickness as seen necessary by the manufacturer. After the winding (62) is made on the winding jig, an ejector plate (66) is used to push the winding off the winding jig.

In alternative embodiments, FRP fabric laminates are used to add reinforcement to the molded one-piece tappet body blank. Fabric laminates are illustrated in Figure 13, with a unidirectional fabric laminate (67) and a plain weave woven fabric laminate (68). In alternative embodiments other fabric weaves, such as twill-weaves, satin-weaves, etc. are used as fabric laminates. FRP windings and/or FRP fabric laminates are used as reinforcement in high- performance applications to increase the strength-to-weight ratio of the tappets, allowing a manufacturer to attain similar or increased tappet strength at a reduced weight.

Before compression molding the BMC or SMC, and/or adding the FRP windings and/or FRP fabric laminates, a layup jig is used to prepare the molded shot. Example layup jigs are illustrated in Figure 14 and Figure 15. The layup jig generally holds the BMC or SMC material (69 and 74), the added FRP windings (70 and 75), and the added FRP fabric laminates (71 and 76) together for preheating. In both thermoset and thermoplastic based materials, preheating the material to be molded together helps to create a stronger part, while also reducing cycle time. This reduction in cycle time in turn reduces manufacturing costs. If the material is thermoplastic based, although optional, it is highly recommended to use a layup jig. Without preheating, the thermoplastic material is hard, and the mold will have to first be heated and then cooled to create the molded part. For thermoset materials, it is recommended to use a layup jig, however it is not necessary because thermoset molding material is generally sufficiently soft to be molded while uncured. In addition, thermoset material cannot be preheated for too long, as doing so causes the molding material to cure within the layup jig.

In embodiments using a layup jig, the steps include preheating molding material together, then inserting the material into the cavity of the mold. To make the material easily transferable to the mold, the layup jig is configured either to allow easy access to the molding material or have an ejector system. The layup jig illustrated in Figure 14 allows for easy access to the molding material, because a base (72) lies within a removable cavity wall (73). The removable cavity wall (73) is pulled up, exposing the molding material. The layup jig in Figure 15 uses an ejector system with the presence of a base (77) and an ejector plate (78). The base (77) and the ejector plate (78) are placed upside down on top of the mold, and the ejector plate (78) is pressed down to push the molding material into the cavity of the mold.

Figure 16 illustrates an expanded view of the pre-molding process in which FRP windings and FRP fabric laminates are added. The BMC or SMC material (79), the FRP windings (80), and the FRP fabric laminates (81) are inserted into the cavity (82) of the mold. The core (83) is then closed to mold these materials together. If FRP windings and/or FRP fabric laminates are being used, the high cavity pressures result in good adhesion and bonding between the different molding materials. A one-piece tappet body blank is manufactured with injection molding. The standard injection molding process for creating a one-piece tappet body blank is illustrated in Figure 17. The one-piece injection molded tappet body blank has the same or very similar geometry to the contour compression molded tappet body blank. The molded part (84) is injection molded out of an FRP material between the cavity (85) and the core (86). The FRP material is injected through the sprue (87) and after the FRP material is solidified, the one-piece tappet body blank is ejected by the ejector pins (88).

Over mold injection molding is also used to add FRP windings and/or FRP fabric laminates to the one-piece tappet blank. Figure 18 illustrates a conceptual, expanded view of the pre-molding process for over mold injection molding with added FRP windings and FRP fabric laminates. The FRP windings (89) and the FRP fabric laminates (90) are inserted into the cavity of the mold (91). The core of the mold (92) then closes on the mold, and FRP material is injected through the sprue (93). The FRP windings and FRP fabric laminates are either inserted dry (without any resin) or inserted wet (with resin impregnated). If the windings and/or fabric material are inserted dry, the injected FRP material has a lower fiber- to-resin ratio so that more of the resin impregnates the winding and/or fabric reinforcement material.

Resin injection molding is also used for creating the one-piece tappet blank. Figure 19 illustrates a conceptual, expanded view of the pre-molding process for a resin injected and over molded one-piece tappet blank with added FRP windings and FRP fabric laminates. The chopped fiber (94), the FRP windings (95), and the FRP fabric laminates (96) are inserted into the cavity of the mold (97). The core of the mold (98) then closes on the mold, and resin is injected through the sprue (99). The chopped fiber, FRP windings, and FRP fabric laminates are generally inserted dry so that no significant cavity pressure is raised until the resin is injected, as the volume of the resin is not added to the part before the resin is injected.

Similar to compression molding, if FRP windings or FRP fabric laminates are added as reinforcements, the high pressures from the injection pressures with injection molding result in combining the different molding materials together and guarantees good adhesion.

After contour compression molding or injection molding the initial one-piece FRP flat tappet body blank, the blank is rough machined through turning, milling, and/or grinding. A one-piece tappet blank is also produced by Standard billet composite machining any of the types of Standard FRP billets described in the definition section.

Manufacturing a two-piece FRP flat tappet body blank:

A two-piece tappet body blank is used in applications in which the manufacturer wants to use a different material in the upper and lower portions of the tappet. This is typically done in applications where the manufacturer wants to reduce the mechanical forces applied to the FRP material or create better wear surfaces.

Alternative methods for connecting the upper and lower bodies of the tappet are illustrated in Figure 20. The upper and lower bodies of the tappet are molded together (100 and 101). Certain embodiments of the bodies that are molded together have a lip (100) to increase the bonding surface area. Embodiments of the upper and lower bodies of the tappet are bonded together (102- 107). Embodiments that are bonded together and connected with a lip (102-106) may include secondary connections with dowel pins (102), a flat spot (103), threads (104), a side pin (105), and/or a vertical key (106) for proper lateral alignment. The upper and lower body bonded together without a lip and connected with dowel pins is shown (107).

A two-piece tappet body blank is manufactured with contour compression molding, where the lower body is made from Standard FRP billet material, a technical ceramic, or metal. The upper body is an FRP material. The molded part is illustrated in Figure 21, which shows the lower body (108) and the upper body (109). The two parts are typically molded together with horizontal undercuts (111), angled undercuts (112), or a combination of both. In addition, a domed shape (110) is generally used to increase adhesion of the final part.

The standard molding process for creating a two-piece tappet body blank is illustrated in Figure 22. The lower body (113) is inserted into the cavity (115) of the mold and the upper body (114) is compression molded from a BMC or SMC between the lower body (113) and core (116). After the BMC or SMC material is solidified into the shape of the upper body (114), the two-piece tappet body blank is ejected by the ejector pins of the mold (117).

Similar to the method described for manufacturing the one-piece tappet body blank, FRP windings and/or FRP fabric laminates in certain embodiments are added as reinforcements to the molded two-piece tappet body blanks. The FRP windings and/or FRP fabric laminates are inserted into the cavity with the BMC or SMC material, and the material is compression molded with the lower body.

Further, similar to the method described for manufacturing the one-piece tappet body blank, a layup jig in various embodiments is used to prepare the mold before compression molding. While using the layup jig for the two-piece tappet body blank, the lower body is placed into the layup jig with the molding material. The layup jig either allows easy access to the molding material or has an ejector system.

Similar to the manufacturing process of the one-piece tappet body blank, a two-piece tappet body blank is also manufactured with injection molding. The standard injection molding process for creating a two-piece tappet body blank is illustrated in Figure 23. Similar to the one-piece tappet body blank, the two-piece injection molded tappet body blank has the same or similar geometry compared to the contour compression molded tappet body blank. The lower body (118) is inserted into the cavity (120) of the mold and the upper body (119) is over mold injection molded between the lower body (118) and core (121). The FRP material is injected through the sprue (122) and forms the upper body (119). After the FRP material is solidified, the two-piece tappet body blank is ejected by the ejector pins (123).

Similar to the method described for manufacturing the one-piece tappet body blank, FRP windings and/or FRP fabric laminates are added as reinforcements to the injection molded two-piece tappet body blanks with over mold injection molding. In this process, the FRP windings and/or FRP fabric laminates are inserted into the cavity dry or wet with the lower body, the core closes, and FRP material is then injection molded.

Similarly, resin injection molding is also used for the two-piece tappet body blank. In this process, dry chopped fiber is inserted into the cavity with the lower body, the core closes, and resin is injected. In certain embodiments, dry FRP windings and/or dry FRP fabric laminates are inserted with the chopped fiber and lower body for additional reinforcement.

A two-piece tappet body blank is in alternative embodiments made by bonding separate upper and lower bodies together with a thermoset or thermoplastic adhesive. In an embodiment of this process both the lower body and upper body are machined before bonding. The upper body and lower body are connected and lined up with various methods, illustrated in Figure 20. Embodiments include the upper and lower body bonded with a lip and dowel pin (102), or with a lip and flat spot (103), or with a lip and threads (104), or with a lip and side pin (105), or with a lip and vertical key (106), or without a lip and with dowel pins (107).

The lower body is a metal, technical ceramic, or any of the types of Standard FRP billets described in the definition section.

The upper body is contour compression molded, injection molded, or machined from any types of Standard FRP Billets. The procedure for contour compression molding the upper body, is similar to manufacturing a one-piece blank is contour compression molded, in which fiber winding reinforcements, fabric fiber reinforcements, a winding jig, and/or a layup jig are used/added. The upper body is manufactured by injection molding similar to the procedure for manufacturing an injection molded one-piece blank, in which over molding, resin injection molding, added winding reinforcement, added fabric reinforcement, and/or added chopped fiber are used/added.

After contour compression molding, injection molding, or bonding the initial two- piece FRP flat tappet body blank, the blank is rough machined through turning, milling, and/or grinding.

Secondary processing:

After creating the one-piece or two-piece tappet body blank, any combination or permutation of the following methods may be used to turn the blank into the final tappet.

Creating the cup contact surface: Embodiments of cup contact surfaces are illustrated in Figure 24. If the tappet-body blank is a one-piece blank, the cup is a separate piece (124) or is directly machined into the body of the tappet (125). If the tappet-body blank is a two- piece blank, the cup is a separate piece that is bonded to the upper body (126) or a stem of the lower body (127), or the cup is directly machined into the upper body (128) or into a stem of the lower body (129). Creating the cup contact surface includes alternatively machining the separate cup piece or machining the cup surface directly into the tappet blank. In addition, if the tappet body blank is contour compression molded or injection molded, the cup surface is molded as part of the tappet body — in which case, the cup surface typically needs a finishing step to ensure dimensional accuracy and an adequate surface finish. If the cup is directly machined or molded into an FRP body, generally a coating is required to create a good bearing surface. If the cup is a separate piece, it is made of metal or a technical ceramic.

Assembly: If the tappet body blank is two-pieces and bonded together, the assembly step consists of bonding the upper and lower body together with a thermoset or thermoplastic adhesive.

Finishing: With good control from molding or initial machining (the machining performed on the upper and lower body before bonding for a two-piece bonded tappet body blanks), these processes may not be required. However, typically the OD (outside diameter) of one-piece bodies (or the lower bodies of two-piece tappet body blanks), the bottoms of one-piece bodies (or the lower bodies), and cup registers are finished to a 0-63 microinch Ra finish by a combination or permutation of any of the following methods: milling, grinding, turning, lapping, polishing, vibratory finishing, or electropolishing. The OD of the FRP upper bodies is also occasionally finished, normally together with the lower bodies to create one continuous surface.

Vapor Deposited Coating: A vapor deposited coating is applied onto the tappet blanks. The vapor deposited coating is used to create anti-friction and/or anti-wear surfaces. The coating is chosen from any of the following: DLC, MoS2, any technical ceramic (such as but not limited to TiN, ZrN, CrN, TiCN, CrCN, TICrN, AlTiN, or AlCrN), any metal (such as but not limited to aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, or zinc), and a combination of MoS2 on any technical ceramic (such as but not limited to TiN, ZrN, CrN, TiCN, CrCN, TICrN, AlTiN, or AlCrN) or any metal (such as but not limited to aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, or zinc). The vapor deposited coating is applied over the entire tappet or a combination of specific areas (such as the bottom of the one-piece body (or lower body), the cup registers, and/or the outside diameter).

Electroplating: The tappet blanks are electroplated with a metal (such as but not limited to aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, or zinc) to create an anti-friction and/or anti- wear surface. Because FRP material is generally not electrically conductive, an initial conductive coating is typically applied in an electroless plating process before electroplating (such as through a vapor deposited coating). Similar to applying a vapor deposited coating, the entire tappet blank or a combination of specific areas (such as the bottom of the one-piece body (or lower body), the cup registers, and/or the outside diameter) is electroplated.

Plasma Spray Coating: The tappet blanks are also optionally plasma spray coated to create a thermal barrier coating layer (which in certain embodiments is necessary for high- temperature applications with low-temperature resins), anti-friction surface, and/or anti-wear surface. The coating is selected from any of the following: pure molybdenum or MoS2, a technical ceramic (such as but not limited to YSZ, Zirconia, Yttria, Aluminum Oxide, Chromium Oxide, Mullite, Spinel, Titania, Tungsten Carbide, or Chromium Carbide), a metal (such as but not limited to aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, or zinc), or a combination of pure molybdenum or MoS2 on top of a technical ceramic (such as but not limited to YSZ, Zirconia, Yttria, Aluminum Oxide, Chromium Oxide, Mullite, Spinel, Titania, Tungsten Carbide, or Chromium Carbide) or a metal (such as but not limited to aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, or zinc). Similar to applying a vapor deposited coating, the plasma spray coating is applied over the entire tappet or a combination of specific areas (such as the bottom of the one-piece body (or lower body), the cup registers, and/or the outside diameter).

Painting: The tappet blanks are also optionally coated with painting. Paints that are used are ceramic paints (such as but not limited to Yttria stabilized Zirconia paint, Zirconia paint, or Aluminum Oxide paint), metallized paints (such as but not limited to aluminum, brass, cadmium, chromium, copper, gold, iron, molybdenum, nickel, silver, titanium, or zinc paint), anti-friction paints (such as but not limited to a MoS2 paint, pure molybdenum paint, or graphite paint), or an anti-friction paint that is layered on top of a metallized or ceramic paint. These paints typically need extra thermal or chemical treatment to bum off the plastic component and leave just the technical ceramic, metal, or anti-friction substance on the part. Similar to applying a vapor deposited coating, the paint is applied over the entire tappet a combination of specific areas (such as the bottom of the one-piece body (or lower body), the cup registers, and/or the outside diameter). Paint is most commonly applied on the entire surface of the tappet by dipping the tappet blanks into wet paint.

Dry Film Coating: The tappet blanks are also optionally coated with a dry film coating to create anti-friction surfaces. The dry film coating is either Molybdenum Disulfide (MoS2), Tungsten Disulfide (WS2), or Graphite. Similar to applying a vapor deposited coating, the dry film coating is applied to the entire tappet or a combination of specific areas (such as the bottom of the one-piece body (or lower body), the cup registers, and/or the outside diameter). Dry film coatings are most commonly applied on the OD and the bottom of the one-piece body (or lower body) to allow ease of sliding within the tappet bore and decrease the coefficient of friction between the tappet and camshaft respectively.

Shot Peening: The tappet blanks are also optionally shot peened to improve the mechanical properties and fatigue life of the tappets. Similar to applying a vapor deposited coating, the shot peening is applied to the entire tappet or a combination of specific areas (such as the bottom of the one-piece body (or lower body), the cup registers, and/or the outside diameter). Shot peening is most generally used on the bottoms of the lower bodies of the tappet in embodiments in which the tappet body blank is two-piece and the lower body is metal, as shot peening may destroy FRP or technical ceramic materials. Shot peening results in a surface that is plastically deformed and rough, which in various embodiments requires an additional finish.

Finishing the Coatings: Upon applying a relatively thick coating on the tappet blanks with electroplating, plasma spray coating, painting, and/or dry film coating, or plastically deforming a surface with shot peening, certain areas may need to be finished. While the entire tappet may be finish machined after adding a coating, typically, only certain specific areas need finishing, such as the bottom of the one-piece body (or lower body), the cup registers, and/or the outside diameter. These areas and dimensions are finished in a combination or permutation of the following methods: milling, grinding, turning, lapping, polishing, vibratory finishing, or electropolishing.

Heavy Metal Ion Implantation: During any steps of the manufacturing process described, the tappet blanks are subjected to heavy metal ion implantation (HMII) treatment. HMII treatment typically occurs after machining. HMII treatment that occurs before coatings is applied typically to enhance the mechanical properties of the part (such as by increasing stiffness, strength, and fatigue properties). On the other hand, HMII treatment that occurs after coatings is applied to enhance (such as by increasing microhardness and wear resistance) the effects of the coatings. In certain embodiments, HMII treatment is applied at any manufacturing step and potentially multiple times to the tappet blanks to enhance the properties that the manufacturer desires. Sodium Silicate Impregnation: Typically, the last step of production, tappet blanks are sealed with sodium silicate impregnation. Sodium silicate impregnation mitigates the undesirable hygroscopic effects experienced by the parts being treated. Sodium silicate impregnation is an important step because without sodium silicate impregnation, the FRP tappets uptake fluid (such as oil) in an engine, increasing the weight and degrading the structural integrity of the tappets. Sodium silicate impregnation is typically the last step because outgassing occurs if parts are subjected to HMII after sodium silicate impregnation. In addition, sodium silicate impregnation occurs after all machining is completed and all coatings are applied to seal the outside surfaces that are exposed to fluids within an engine.

Fiber reinforced polymer (FRP) Roller tappets:

Exemplar features of a roller tappet are illustrated in Figure 25. Roller tappets have a roller wheel (130) that rides on the camshaft and an axle (131) for that wheel. The axle is connected to the body of the tappet with two axle-register-holes (132), and a wheel space profile (133) gives clearance for the wheel.

The process for creating FRP roller tappets is similar to the process for creating flat tappets, in which the tappet body blank is made as a one-piece or two-piece body blank by various methods and then undergo secondary processing. Creating FRP roller tappets contains minor adjustments and additions to create the rollers and mechanisms that keep the tappets straight (flat spots, tie bars, and/or keyways). The following sections contain these additions and/or adjustments.

One-piece roller tappet body blanks: Different molded parts for one-piece roller tappet body blanks are illustrated in Figure 26.

For creating a one-piece roller tappet body blank by contour compression molding, the blank in certain embodiments has a wheel space profile that comes directly from the mold (134). For in injection molding, the wheel space profile may also be molded (135). Molding in the wheel space typical increases mechanical properties of the final part by reducing the quantity of fibers that are cut during machining, and reduces manufacturing costs due to reduced needed machining and material usage.

In an alternative embodiment, contour compression molding or injection molding molds a roller tappet body blank that does not have its wheel space molded in (136). In contrast to these methods, one-piece roller tappet body blanks made by machining a standard FRP billet require machining for the wheel space profile.

Two-piece roller tappet body blanks: For creating a two-piece roller tappet body blank by contour compression molding, the lower body may be machined before molding so that the molded part comes out with the axle-register-holes and/or the wheel space profile already molded in. Figure 27 illustrates a roller tappet body blank that has a thick lower body already containing the axle-register-hole and wheel space profile (137) and a roller tappet body blank that has a shelled lower body already containing the axle-register-hole and wheel space profile (138). The same is true for injection molding, where the lower body may already contain the axle-register-hole and/or wheel space profile and be thick (139) or shelled (140). The lower body is typically shelled to reduce weight when it is made from a heavier material.

The standard molding process for creating a two-piece tappet body blank is illustrated in Figure 22. The lower body (113) is inserted into the cavity (115) of the mold and the upper body (114) is compression molded from a BMC or SMC between the lower body (113) and core (116). After the BMC or SMC material is solidified into the shape of the upper body (114), the two-piece tappet body blank is ejected by the ejector pins of the mold (117).

Similar to the manufacturing process of the one-piece tappet body blank, a two-piece tappet body blank is also manufactured with injection molding. The standard injection molding process for creating a two-piece tappet body blank is illustrated in Figure 23. Similar to the one-piece tappet body blank, the two-piece injection molded tappet body blank has the same or similar geometry compared to the contour compression molded tappet body blank. The lower body (118) is inserted into the cavity (120) of the mold and the upper body (119) is over mold injection molded between the lower body (118) and core (121). The FRP material is injected through the sprue (122) and forms the upper body (119). After the FRP material is solidified, the two-piece tappet body blank is ejected by the ejector pins (123).

Figure 28 depicts the molding process for creating a two-piece contour compression molded and two-piece injection molded roller tappet blank that both already have their axlewheel profiles and wheel space profiles made before molding.

Similar to flat tappet body blanks, for contour compression molding, the lower body (141) is inserted into the cavity (143) of the mold and the FRP upper body (142) is compression molded between lower body (141) and core (144). After the FRP is solidified into the shape of the upper body (142), the two-piece tappet body blank is ejected by the ejector pins of the mold (145). Fiber winding reinforcements, fabric fiber reinforcements, a winding jig, and/or a layup jig may be used/added.

Similar to flat tappet body blanks, for injection molding, the lower body (146) is inserted into the cavity (148) of the mold and the upper body (147) is over mold injection molded between the lower body (146) and core (149). The material is injected through the sprue (150) and forms the upper body (147). After the FRP material is solidified, the two- piece tappet body blank is ejected by the ejector pins (151). Over molding, resin injection molding, added winding reinforcement, added fabric reinforcement, and/or added chopped fiber may be used/added.

The two-piece roller tappet body blank is also contour compression molded or injection molded without its axle-register-hole and/or wheel space profile whereby the axle- register-hole and wheel space profile are machined, and the machining intersects the upper body. Exemplary two-piece roller tappet blanks that have their axle-register hole and wheel space profile machined into the blank after either molding or bonding the upper and lower bodies together are illustrated in Figure 29. The blank can have the axle-register-hole and wheel space profile shared in the lower and upper body (152), or have just the axle-register- hole shared (153), or have just the wheel space profile shared (154), or have both the axle- register-hole and wheel space profile only in the lower body (155).

If the two-piece roller tappet body blank is bonded together, the axle-register-hole and/or wheel space profile is machined into the lower body before or after bonding. However, also as depicted in Figure 29, part of the axle-register-hole and/or wheel space profile is shared with the upper body as well.

Wheel: The wheel for the tappets is either full or cutout, as seen in Figure 30. The wheel is full (156) or cutout (157). Typically, full wheels are used on tappets that run against high spring or cylinder pressures, and cutout wheels are used on tappets that run against low spring or cylinder pressures in order to save weight.

The wheel is made out of metal, technical ceramic, or FRP. If the wheel is made from FRP, the wheel would typically have a majority of fibers oriented in the 90-degree direction for radial crushing strength and be made by roll wrapping or filament winding. However, the wheel in various alternative embodiments is also made by any of the standard FRP Billet composite manufacturing methods herein.

After the body of the wheel is constructed, any permutation or combination of the secondary processing methods used for the flat tappet section discussed herein are used to finish the wheel, such as: finishing processes (milling, grinding, turning, lapping, polishing, vibratory finishing, or electropolishing), adding a vapor deposited coating, electroplating, adding a plasma spray coating, painting, adding an anti-friction dry film coating, shot peening, utilizing heavy metal ion implantation, and sodium silicate impregnation.

Axle: The axle is made of metal, technical ceramic, or FRP. If the axle is made from FRP, it typically has a majority of fibers oriented in the 0-degree direction for flexural and shear strength, with some fibers oriented off-axis to prevent resin expansion. This is typically accomplished by using a pultruded rod with an outside roll wrapped or filament wound layer. However, it may also be made by any of the standard FRP Billet composite manufacturing methods discussed herein. Similar to the wheel, any permutation or combination of the secondary processing methods discussed herein may be used to finish the wheel.

Connection between the wheel and axle: Different connections between the axle and wheel are illustrated in Figure 31. The wheel and axle directly run on each other (158), use needle bearings (159), or use a bushing (160). If the wheel and axle directly run on each other or utilize a bushing, the OD of the axle and ID of the wheel and/or bushing typically require a 0-63 Ra finish between them to create a good running surface.

Connection between the axle and body: During running, different methods must be used to secure the axle to the body of the tappet and stop the axle from sliding back and forth. Exemplar connection methods are depicted in Figure 32. The roller tappet may use pins (161 and 164), set screws (162 and 165), and/or a thermoset or thermoplastic adhesive (163 and 166) to stop the axle from sliding back and forth.

Flat spotted tappets: Flat spotted tappets have a flat spot register that consists of flat spots on the upper part of the tappet. Figure 33 illustrates an exemplar flat-spotted tappet (167), the lifted area around the tappet (168), and the flat spots (169). If the tappet body blank is manufactured with contour compression molding or injection molding, the lifted area and flat spot register are directly molded into the tappet. In alternative embodiments, these areas are machined after molding, and need to be machined if the tappet body blank is created by machining one of the standard FRP Billet composites.

Tie bar tappets: Tie bar tappets have a tie bar register on the upper part of the tappet. Figure 34 illustrates the lifted areas around tie bar tappet (170). Similar to the flat spotted tappet, if the body blank is manufactured with contour compression molding or injection molding, the lifted area may be directly molded into the tappet. However, like the flat spotted tappet, these areas are machined after molding and need to be machined in if the tappet body blank is machined from one of the standard FRP Billet composites. The tie bar register uses a rivet (171) or a bolt and nut (172) to connect to the tie bar. This rivet or bolt hole is typically machined into the tappet.

Different types of tie bars are illustrated in Figure 35. The tie bar may be straight (173) or bent (174), and they typically have a hole (175) and slot (176). However, tie bars may also have two holes or two slots, depending on the application. The tie bars are manufactured from metal, technical ceramic, thermoset plastic, thermoplastic plastic, or FRP.

Key way tappets: Key way tappets have a key on the upper part of the tappet that slides into a dedicated slot for alignment. Figure 36 illustrates the lifted area around key way tappets (177). Like the flat spotted and tie bar tappets, if the body blank is manufactured with contour compression molding or injection molding, the lifted area may be directly molded into the tappet. However, this area is machined after molding and needs to be machined if the tappet body blank is machined from one of the standard FRP Billet composites.

The key may be the same piece as the body of the tappet (178 and 180) which is manufactured by molding in the key if the tappet body blank is made by contour compression molding or injection molding. The key can also be manufactured through machining, which would be performed by machining the area around the key. The key can also consist of a separate part (181) that is inserted into a machined hole in the lifted area for the key (179). Extra material (182) may be added around the inserted key (181) as structural support.

Metal roller tie bar tappets with a plastic of FRP tie bar:

Also included within this invention are tie bars that are made of plastic of FRP. These tie bars may be used with both conventional metal tappets and FRP tappets. Figure 35 illustrates that the tie bar may be straight (173) or bent (174), and the tie bar typically has a hole (175) and slot (176). However, the tie bar may also have two holes or two slots, depending on the application of the tie bar.

If the tie bar blank is made from plastic, the blank is made from thermoset plastic material or thermoplastic plastic material. The plastic tie bar blank may be made by any permutation of combination of the following processes: machining a plastic billet, plastic casting, injection molding, and compression molding. If the blank is made from FRP, it is injection molded, contour compression molded, or made from any of the standard FRP Billet composite manufacturing methods described herein. Similar to the tappet body blanks, for contour compression molding the tie bar blank, fiber winding reinforcements, fabric fiber reinforcements, a winding jig, and/or a layup jig may be used/added. Similar to the tappet body blanks, for injection molding the tie bar blank, over molding, resin injection molding, added winding reinforcements, added fabric reinforcements, and/or added chopped fiber may be used/added.

After the plastic or FRP tie bar blank is initially manufactured, any permutation or combination of the secondary processing methods discussed herein are used to finish the tie bar, such as: finishing processes (milling, grinding, turning, lapping, polishing, vibratory finishing, or electropolishing), adding a vapor deposited coating, electroplating, adding a plasma spray coating, painting, adding an anti-friction dry film coating, shot peening, utilizing heavy metal ion implantation, and sodium silicate impregnation.

The instant invention has been shown and described in what are the most practical and preferred method steps. It is recognized, however, that departures may be made within the scope of the invention and that modifications will occur to a person skilled in the art. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function, steps, and manner of operation, assembly, and use, would be apparent to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact constructions and operations shown and described, and accordingly, all suitable modifications and equivalents may be resorted to falling within the scope of the invention.