Field

[001] This application provides a plunger for a castellation assembly. A rack and pinion design couples the plunger to a castellation device.

Background

[002] Castellation assemblies can be used in valvetrains. Many examples exist in the art, placing castellation assemblies in rocker arms, rocker towers, among other locations. At times, castellation assemblies are housed in a capsule for drop-in installation in the valvetrain.

[003] A castellation device of the prior art can comprise a crown that is rotated by various means. Prior art plunger arrangements comprise a single tooth or a spiral-cut on the body of the plunger. The single tooth has disadvantages. For example, the tooth can be large to yield appropriate fatigue strength, taking a lot of room in the valvetrain. The spiral cut plunger is hard to align as the castellation device is dropped in, making actuation accuracy difficult.

SUMMARY

[004] The methods and devices disclosed herein overcome the above disadvantages and improves the art by way of plunger design that aligns easily with the castellation device, that offers good actuation accuracy to align the castellation device in a locked or unlocked position, and that offers compactness in the rack and pinion coupling.

[005] A castellation assembly can comprise a castellation device comprising an upper crown and a lower crown configured to selectively lock and unlock. At least one of the upper crown and the lower crown comprises outer pinion teeth. A plunger can comprise rack teeth in a parallel pattern that provides a line contact to engage the outer pinion teeth. A rocker arm can comprise the castellation assembly. A bore can be for receiving the castellation device and a plunger bore can be for receiving the plunger. The bore overlaps the plunger bore in a shared space so that the castellation device and the plunger provide a positive engagement between the outer pinion teeth and the rack teeth in the shared space. [006] Additional objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. The objects and advantages will also be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[007] Figure 1 A is shows an unlocked castellation device of a castellation assembly.

[008] Figure 1 B shows a locked castellation device of a castellation assembly.

[009] Figure 2 is partial assembly view of the castellation assembly.

[010] Figures 3A-3C are alternative views of plungers.

[011 ] Figures 4A & 4B are alternative views of castellation assemblies installed in a valvetrain member body. [012] Figure 5 is a view of an exemplary rocker arm.

DETAILED DESCRIPTION

[013] A castellation assembly 1 , 2, 3 can comprise a castellation device 10 comprising an upper crown 110 and a lower crown 120 configured to selectively lock and unlock. One of the upper crown 110 and the lower crown 120 comprises outer pinion teeth 113. A plunger 200 can comprise rack teeth 220, 2201 , 2202 in a parallel pattern that provides a line contact to engage the outer pinion teeth 113.

[014] Upper crown 110 can comprise an upper body 111. Upper locking teeth 114 can be separated by upper gaps 115. An exterior surface 112 of the upper body 111 can comprise outer pinion teeth 113. Alignment structures can also extend from the upper body 111, such as upper support 116 that can interleave against the lower crown 120 or can abut a portion of the bore 301. Other alignment tabs or bodies are known in the art for positioning the upper crown 110 in the bore 301.

[015] Lower crown 120 can comprise a lower body 121 from which lower locking teeth 124 can extend. Lower locking teeth 124 can be separated by lower gaps 125. Lower crown 120 can comprise a tab or rim or other alignment structure to fit in tab slot 302 or guide wall or other alignment feature of bore 301 so that lower crown 120 is rotationally fixed in bore 301. By rotating the upper crown 110 relative to the lower crown 120, the upper locking teeth 124 can abut the lower locking teeth 124 to lock the castellation device like Figure 1 B. Or, the upper locking teeth 124 can align with lower gaps 125 while lower locking teeth 124 align with upper gaps 115 like Figure 1A to unlock the castellation device. When upper and lower locking teeth 114, 124 face one another, the castellation device 10 is one length during a force transfer (FIG 1 B). When the upper and lower locking teeth 114, 124 align with corresponding upper and lower gaps 115, 125, a second length is achieved when the castellation device 10 collapses (FIG. 1A). Controlling the locking and unlocking of the castellation device 10 by moving the plunger 200,

2001 , 2002 against the outer pinion teeth 113 permits variable valve actuation (“WA”) in a valvetrain by adjusting an amount of force transfer to a valve. Engine braking is a common WA technique, but other WA can include cylinder deactivation, early or late valve opening or closing, and combinations thereof. A valvetrain member body 300 can be a rocker arm 350 that receives actuation force from a cam, or valvetrain member body 300 can be part of a rocker tower transferring force from a push tube, among other options. The rocker arm 350 of Figure 5 is exemplary, with many alternatives known in the art.

[016] Numerous alternatives exist in the art for biasing and supporting the upper crown 110 and lower crown 120 in bore 301. Guide body 130, spigot 135, locking nut 136, and e-foot (elephant foot) 140 are exemplary. Inner workings, such as one or more lost motion spring, spacers, third crown, among many alternatives are compatible with the teachings herein. In addition, a three-crown structure can be achieved, or the crown assembly can be inverted so that the lower crown 120 rotates while the upper crown 110 is fixed.

[017] Outer pinion teeth 113 and rack teeth 221 , 2211 , 2212 can comprise complementing shapes seen in gear pairings. Parallel patterns that provide line contact between the outer pinion teeth 113 and rack teeth 221 , 2211 , 2212 can be configured for providing positive engagement and in-tandem motion. The parallel patterns increase the area of contact & reduce actuation stresses. Complementing positive and negative patterns can comprise involute-to-involute tooth pairings (Figs. 1A, 1B, 4A) or involute-to-triangle tooth pairings (Fig. 4B), which are non-exhaustive examples. Other involute patterns can be used, such as those seen in spur gears. The triangle shape can be put on the outer pinion teeth 113 with the involute shape can be included on the plunger 200. The shapes are chosen to yield positive gear contact characterized as a line contact. This differs from prior art points of contact provided by screw-type plungers. This also differs from single-tooth plungers.

[018] Plunger 200 includes a rack 220, 2201 , 2201 that is designed to align easily with the castellation device 10. By having parallel outer pinion teeth 113, the upper crown 110 is easily dropped in bore 301 so that rack teeth 221 , 2211 , 2212 align therewith. This would not be so easily achieved with a spiral-tooth plunger as there would be risk of the plunger sliding or the upper crown 110 rotating during the drop-in assembly, which would result in inaccurate alignment or difficult recalibration. The line contact between the outer pinion teeth and the rack teeth 221 , 2211 , 2212 offers good actuation accuracy to align the castellation device 10 in a locked (FIG. 1B) or unlocked (FIG. 1A) position because the positive engagement is less prone to the slipping of a point contact provided by a spiral-cut plunger. Sure actuation is also provided by the multiple parallel teeth of the rack 220, 2201, 2202 because if a single tooth plunger slips, there are no other teeth to actuate with, while a multi-tooth rack 220, 2201 , 2202 could at least be recalibrated and used at the slipped position. The multi-tooth rack 220, 2201 , 2202 is also more compact for two reasons. The rack teeth 221 , 2211 , 2212 can be shorter than that used in a single tooth design because the multiple rack teeth 221 , 2211 , 2212 can share actuation forces in a distributed fashion that the single tooth plunger would otherwise concentrate on the one tooth. Compactness in the rack and pinion coupling is also achieved because the shorter multiple rack teeth 221 , 2211 , 2212 enable the plunger bore 310 to overlap with the bore 301. A rocker arm 350 or other valvetrain member body 300 comprising the castellation assembly 10 can benefit from the use of a shared space for compactness. A bore 301 can be for receiving the castellation device 10 and a plunger bore 310 can be for receiving the plunger 200, 2001 , 2002. It can be said that the plunger bore 310 is transverse to the bore 301 , the actuation direction of the plunger 200, 2001 , 2002 being transverse to the actuation direction of the castellation device 10. The bore 301 overlaps the plunger 310 bore in a shared space so that the castellation device 10 and the plunger 200, 2001, 2002 provide a positive engagement between the outer pinion teeth 113 and the rack teeth 221 , 2211 , 2212 in the shared space. [019] So, it can be said that the line contact is provided by a positive engagement profile comprising complementing gear pairs formed by the outer pinion teeth 113 and the rack teeth 221 , 2211 , 2212. The rack teeth 221 , 2211 ,

2212 comprise, as options an involute tooth profile or a triangular tooth profile.

In a complementary manner, outer pinion teeth 113 can comprise an involute tooth profile or a triangular tooth profile.

[020] As options, the rack teeth 2202 can encircle the plunger 2002. A turning technique can be used, for example, or casting or molding. Or, the rack teeth 221 , 2211 can be formed to project from a plane R of the plunger 200, 2001. A grinding technique can be used, for example, or casting or molding.

[021 ] The plunger 200, 2001 , 2002 can comprise a plunger body 210, 2101, 2102 comprising a first guide area 212, 2121 , 2122 and a second guide area 213,

2131 , 2132. The second guide area 213, 2131 , 2132 can abut the plunger bore 310 in a way that seals hydraulic or pneumatic pressure near port 320 to form an actuation chamber. The combination of first guide area 212, 2121, 2122 and second guide area 213, 2131 , 2132 having the larger Y measurement, the hydraulic or pneumatic control does not leak over the rack teeth 221 , 2211 , 22122.

[022] First guide area 212, 2121 , 2122 and second guide area 213, 2131 , 2132 can abut the plunger bore 310 to guide the rack 220, 2201 , 2202 while yielding a space savings. The outer pinion teeth 113 can extend a bit into the plunger bore 310, yielding a tight packaging. Guiding or sealing portions formed by first guide area 212, 2121 , 2122 and second guide area 213, 2131 , 2132 can be of Y mm in outer diameter. The tooth height can be X mm, with X < Y. The rack 220, 2201 ,

2202 being the fixation point with the upper crown 110, it can be said that the rack area is a boss of the plunger 200, 2001 , 2002. Then it can be said that the boss has a measurement X that is a smaller diameter than the measurement Y that is the diameter of the first guide area 212, 2121 , 2122 and the second guide area 213, 2131 , 2132. The rack 220, 2201 , 2202 can also be said to step-down from the first and second guide areas 212, 2121 , 2122, 213, 2131 , 2132, due to the measurement differences between X & Y. The anti-rotation slot 214 can form another diameter change in the outer surface of the plunger body 210, 2101 , 2102. With this guidance, the rack 220, 2201, 2202 does not jiggle in the plunger bore 310, but firm locating of the outer pinion teeth 113 relative the rack 220, 2201 , 2202 can be assured. Increased area of contact of the guiding surfaces of first guide area 212, 2121 , 2122 and second guide area 213, 2131 , 2132 also leads to lesser stresses under dynamic loading conditions.

[023] A nipple 211, 2111 can be included on first guide area 213, 2131 to space the plunger 200, 2001 from an end of the plunger bore 310. First guide area 212, 2121 , 2122 and second guide area 213, 2131 , 2132 can abut plunger bore 310 in a way that limits uneven pressures like angling or wedging. Plunger 200, 2001 , 2002 slides smoothly in the plunger bore 310 and cannot twist or mis-align nor essentially screw itself into a different thread location.

[024] Plane R can intersect the rack 220, 2201 and can form a place from which the rack teeth 221 , 2211 project. First guide area 212, 2121 can be on a first side of the rack teeth 221 , 2211. Second guide area 213, 2131 can be on a second side of the rack teeth 221 , 2211. The rack teeth 212, 2121 can be recessed in the plunger body 200, 2001 so that the first guide area 212, 2121 and the second guide area 213, 2131 project past the rack teeth 212, 2121. The tips 224 of the rack teeth 221 and the points 2241 of the rack teeth 2211 are recessed from the outer circumferences of the plungers 200, 2001 as can be seen by comparing the measurements X & Y in Figures 3B & 3C. Such can be applied also to the plunger 2002. Recessing the rack teeth 221 , 2211 , 2212 in this way prevents the rack teeth 221 , 2211 from rubbing on the plunger bore 310, but also facilitates the compactness of the castellation assembly 1, 2, 3. The shared space mentioned above can comprise the outer pinion teeth 113 extending into the circumference of the plunger 200, 2001 , 2002. The outer pinion teeth 113 extend past the outer boundary represented by the measurement Y and the outer pinion teeth 113 extend into the plunger 200, 2001 , 2002 to form the line contact radially inward of the measurement X. Engagement surfaces 222, 2221 , 2222 positively engage the outer pinion teeth 113. Castellation assembly 1, 2,3 can comprise a crown, here upper crown 110, comprising straight-edged outer pinion teeth 113 and the actuation plunger 200, 2001 , 2002 also comprising straight-edged rack teeth 221 , 2211 , 2212. As options, a flat tip 224 can be used, or the point 2241 , or even a curved top.

Roots 223, 2231 can be formed curved or flat and roots 223, 2231 can provide a clearance between the tips of outer pinion teeth 113 and the plane R. outer pinion teeth 113 can be formed with similar options in tip, point, root, and engagement surfaces with adjustments made for the curved exterior shape of the upper or lower crown to which those options are applied. Meshing of the outer pinion teeth 113 with the rack teeth 221 , 2211 , 2212 can thus have various options.

[025] Encircling teeth are typically machined much like a traditional screw, having a thread size, tooth size, and being a spiral pattern about the plunger. But, the plunger 200, 2001 , 2002 herein differs from the prior screw type design. It is easier to form a set of rack teeth 221 , 2211 in only a portion of the plunger 200,

2001. Forming a plane R in a plunger 200, 2001 with “flat” rack teeth 221 , 2211 is easier from a manufacturing standpoint than forming “radial” rack teeth 2212 that go all the way around a plunger 2002. But while the radial rack teeth 2212 can rotate in the plunger bore 310 and still actuate against the outer pinion teeth 113, the flat rack teeth 221 , 2211 cannot rotate in the plunger bore 310 with the same freedom. So, the plunger 200, 2001 can comprise a slot 214 for receiving an anti-rotation device 330. The slot 214 can serve as a travel limit for the plunger 200, 2001 , which can provide further actuation accuracy of the castellation device 10. The slot 214 can help prevent overtravel of the plunger 200, 2001 and can prevent overtravel of the meshed upper crown 110. The slot 214 and anti-rotation device 330 can ensure the positive engagement between the outer pinion teeth 113 and the rack teeth 221 , 2211. It can be possible to include the slot 214 on the plunger 2002.

[026] A key hole 215, 2151 , 2152 can be formed in the second end 213,

2131 , 2132 of plunger 200, 2001 , 2002 so that an alignment tool can be inserted to hold the plunger 200, 2001, 2002 in position during installation in plunger bore 310. Key hole 215, 2151, 2152 can be used also for mechanical connection such as a solenoid plunger or other linkage for moving the plunger 200, 2001 , 2002.

Optionally, the key hole 215, 2151 , 2152 can extend inside the plunger 200, 2001 , 2002 for light weighting.

[027] The rocker arm 350 or other valvetrain component can comprise an anti-rotation bore 340 in the valvetrain member body 300. The anti-rotation bore 340 can be connected to the plunger bore 310. An anti-rotation device 330 such as a pin, screw, bolt, plug, among others can be mounted in the anti-rotation bore 340. The slot 214, 2141 in the plunger 200, 2001 can be configured to receive the anti rotation device 330. [028] Other implementations will be apparent to those skilled in the art from consideration of the specification and practice of the examples disclosed herein.