The invention relates to a wheel axle suspension bearing assembly, the assembly being adapted for coupling a trailing arm having an eye to a vehicle chassis.

A wheel axle suspension bearing assembly is known from GB2257670. There, an assembly is disclosed comprising a pivot bolt, a bearing bracket adapted to be mounted to the vehicle chassis - which bearing bracket has two side plates each having a slotted hole for receiving the pivot bolt - and an eccentric disc for adjustment of the pivot bolt in a direction along the slotted hole. The eccentric disc has a disc shaped body which is arranged on an outer side of a side plate of the bearing bracket, and a bushing which is received rotatably and movably in the slotted hole. The pivot bolt passes through the slotted hole within an opening in the bushing of the eccentric disc.

It is an object of the invention to provide an alternative wheel axle suspension bearing assembly. It is a further object of the invention to improve the life expectancy of the wheel axle suspension bearing assembly.

This object is achieved by a wheel axle suspension bearing assembly according to claim 1.

The elongate hole may be a rectangular hole with straight transverse end edges at its head ends, i.e. at the short sides of the hole, but may also be a slotted hole, which has circular end edges.

In a pre-assembled state the pivot bolt is mounted non-rotatably in the elongate holes due to the a flat abutment surface, yet the eccentric disc may still be rotated relative to the pivot bolt. Rotating the eccentric disc, or eccentric discs, about the pivot bolt yields a translation of the pivot bolt in the elongate hole, as the alignment of the bolt opening in the eccentric disc is translated along the elongate hole. The elongate holes have a longitudinal axis which is parallel to the longitudinal axis of the vehicle chassis and thus to the longitudinal axis of the vehicle. The adjustment direction in which the pivot bolt can be shifted in the elongate holes is thus parallel to the longitudinal axis of the vehicle. In this way the leading end of the trailing arm can be adjusted in the longitudinal direction of the vehicle. An axle attached to a pair of trailing arms can thus be aligned, such that it extends perpendicular to the longitudinal axis of the vehicle. In an assembled state the eccentric discs are clamped between the side plates and the head and/or tensioning nut(s) of the pivot bolt after tightening of the pivot bolt.

The wheel axle suspension bearing assembly facilitates convenient installation and improved vertical loading of the bearing bracket.

The shaft of the pivot bolt is confined between the upper and the lower edge surfaces of at least one of the elongate holes such that substantial movement of the pivot bolt in a direction perpendicular to the adjustment direction is prevented. Because the flat abutment surface is parallel to the upper and lower surface edge of at least one elongate hole, and the abutment surface engages the upper or lower surface edge, the pivot bolt cannot be rotated in the elongate holes. This is convenient for installation, for example when tightening a tensioning nut on the bolt so as to secure the position of the pivot bolt and eccentric discs. The tensioning nut may be tightened on the pivot bolt with a one-sided operation, as the pivot bolt cannot be rotated during rotation of the tightening of the pivot bolt.

In an embodiment, the flat abutment surface is parallel to the upper surface edge of at least one elongate hole, and engages the upper edge surface. This surface on surface engagement enables a vertical load, originating from the trailing arm and transferred partially through the pivot bolt directly onto the bearing bracket, to be distributed from the trailing arm on the bracket along the respective edge surface of the elongate hole. As the vertical load is distributed over a surface portion of the edge surface, local peak pressures can be prevented. This e.g. reduces risk of damage to the bearing bracket and/or enhance the life expectancy of the bearing assembly, and/or the wheel axle suspension bearing assembly may be utilised for heavier uses, and/or side plates of the bearing assembly may be manufactured of lighter and/or thinner plate material.

In embodiments, the abutment surface extends along the length of the shaft such that the abutment surface is in engagement with the respective upper or lower edge surfaces of both of the elongate holes in the side plates. This is advantageous for surface on surface engagement.

In embodiments, the pivot bolt is provided with spaced apart abutment surfaces along the length of the shaft, each of the abutment surfaces being in engagement with the respective upper or lower edge surface of one of the elongate holes in the side plates. Preferably the pivot bolt has at the spaced apart abutment surfaces an identical outer diameter. In an embodiment, a diameter of a central portion, which central portion is defined between the spaced apart abutment surfaces, is equal to or smaller than an outer diameter of the shaft at the abutment surfaces.

In embodiments, the pivot bolt is provided with one or more pairs of abutment surfaces along the circumference of the shaft, the abutment surfaces of one pair being in engagement with the upper edge surface and the lower edge surface of the same elongate hole such that the pivot bolt is confined in the elongate hole in a direction perpendicular to the adjustment direction, the abutment surfaces preferably being diametrically opposed along the circumference of the shaft.

In embodiments, the abutment surface is a flat side made on a round bolt shaft, e.g. by a flattening process on the round bolt shaft, or by milling the bolt shaft. Alternatively, the abutment surface on the pivot bolt may be manufactured by means of extrusion from a bar of a metal material, wherein an extrusion hole in the extrusion die has a cross section with flattened sides. A bolt head may be butted on the extruded bar, and a thread may be tapped thereon. In another alternative, the pivot bolt may be manufactured by means of a casting process, and a thread may be tapped thereon in a separate process.

In an embodiment, the cross-section of the shaft of the pivot bolt - at the abutment surface and/or along the shaft up to the threaded end portion - has a hexagonal, octagonal or square shape, preferably with rounded corner edges. The rounded edges, e.g. forming an outer diameter of the cross-section, may engage the opening(s) in the eccentric disc(s) so as to promote rotation of the disc(s) relative to the pivot bolt. The rounded edges reduce contact pressure between the edges and eccentric disc.

In embodiments, a further protrusion is arranged at a distance from the elongate hole such that the further protrusion engages the outer contour of the eccentric disc at a third point, and wherein the opening in the eccentric disc is an elongate hole.

In embodiments, the assembly comprises two eccentric discs, each eccentric disc being arranged on an outer side of the respective side plates of the bearing bracket. By the two eccentric discs the position of both end portions of the pivot bolt can be adjusted in the respective elongate holes. Thus the pivot bolt can be positioned perpendicular to the longitudinal direction of the vehicle. In embodiments, one of the side plates is provided with a strut support that is attached to the side plate, the strut support comprising an annular base, wherein the eccentric disc is received within an inner contour defined by the annular base, wherein said inner contour engages the outer contour of the eccentric disc and forms said protrusions such that a cam drive is provided in which a rotational adjustment of the eccentric disc about the pivot bolt induces a translational adjustment of the bolt shaft in the elongate holes.

The annular base of the strut support cooperates with the excentric disc in a similar manner as two or more protrusions that surround the opening in the sidewall of the bearing bracket.

In embodiments, the pivot bolt has on one end a head and a tensioning nut is screwed on the other threaded end portion of the bolt.

In embodiments, the pivot bolt may be a fastener having a shaft, wherein at both ends the shaft is provided with threaded end portions having tensioning nuts being screwed on both ends, wherein at both ends the shaft is provided with threaded end portions. This is advantageous for manufacturing the profiled shafts. It is thus to be understood that the term “bolt” does not only mean a fastener having a shaft with a threaded portion and an integrally formed bolt head at one end, but may also be a shaft with a nut at one end instead of a head.

In a second aspect the invention relates to a wheel axle suspension bearing assembly according to claim 14.

In embodiments, the eccentric disc is bounded on more than half of its circumference by intermittently arranged protrusions.

In a further embodiment, the eccentric disc is bounded on half or more than half of its circumference by a single protruding member which comprises said protrusions.

In a specific embodiment such a single protruding member may be a circular annular base, which may be part of a strut support, e.g. a strut attachment collar.

In embodiments, the protrusions are stamped in the side plates.

The invention also relates to a wheel axle suspension according to claim 18.

The invention also relates to a vehicle, such as a truck, a trailer or a semi-trailer, according to claim 19. The invention will be explained further with reference to the drawings, in which like reference symbols designate like parts. In these drawings:

Fig. 1 illustrates in an isometric view a part of a wheel axle suspension with a bearing assembly according to the invention,

Fig. 2 schematically shows, in an isometric view, a part of the bearing assembly of the wheel axle suspension of Fig. 1,

Fig. 3 shows a cross section through the bearing assembly of the wheel axle suspension of Fig. 1,

Fig. 4A to Fig. 4C show schematically the adjustment of the postion of a pivot bolt in a bearing assembly according to the invention,

Fig. 5A shows in an isometric view an embodiment of a pivot bolt for an assembly according to the invention,

Fig. 5B shows schematically the pivor bolt of Fig. 5A in a slotted hole of the bearing bracket,

Fig. 6A shows in an isometric view another embodiment of a pivot bolt for an assembly according to the invention,

Fig. 6B shows schematically the pivor bolt of Fig. 6A in a slotted hole of the bearing bracket,

Fig. 7A shows in an isometric view yet another embodiment of a pivot bolt for an assembly according to the invention,

Fig. 7B shows schematically the pivor bolt of Fig. 7A in a slotted hole of the bearing bracket,

Figs 8A and 8B show in an isometric view and a side elevational view, repectively, a further embodiment of a pivot bolt for an assembly according to the invention,

Figs 9A and 9B show in an isometric view and a side elevational view, repectively, a further embodiment of a pivot bolt for an assembly according to the invention, Figs 10A and 10B show in an isometric view and a side elevational view, repectively, a further embodiment of a pivot bolt for an assembly according to the invention,

Figs 11 A and 11 B show in an isometric view and a side elevational view, repectively, a further embodiment of a pivot bolt for an assembly according to the invention,

Fig. 12 illustrates in an exploded view a further embodiment of a bearing assembly according to the invention.

Fig. 1 illustrates an air sprung wheel axle suspension 1 for a vehicle, such as a truck, a trailer or a semi-trailer. The suspension has on either lateral side a bearing bracket 2 attached to a chassis beam 3 of a vehicle chassis. Fig. 1 only shows one side of the lateral sides. The bearing bracket 2 comprises a pair of side plates 21 which are opposite each other and spaced apart. The side plates 21 each have an aperture 22 to pass through a pivot bolt as is visible in Fig. 3. The apertures 22 of the respective side plates 21 are in line with each other.

The suspension comprises a trailing arm 4 having a leading end 41 which is positioned between the side plates 21 of the bearing bracket 2 and which is pivotally attached to the bearing bracket 2 by a pivot bolt 5 extending through the leading end 41 of the trailing arm 4 and through the apertures 22 in the side plates 21 of the bearing bracket 2, which is best visible in the cross section in Fig 3.

An air spring 6 is mounted to the trailing arm 4 at a trailing end 42 of the trailing arm 4, which is remote from the pivoting leading end 41. The air spring 6 supports the chassis beam 3 in this particular embodiment.

Between the leading end 41 and the trailing end 42, the trailing arm 4 is rigidly attached to an axle body 9. The axle body 9 is in the example of Fig. 1 a thin-walled tubular axle body with a circular cross section. Other axle body shapes are also possible.

In the embodiment of Fig. 1 the trailing arm 4 is a two-part trailing arm, which has a front part and a rear part, wherein on both parts a respective axle seat portion 43, 44 is formed. The axle seat portions 43 and 44 are positioned opposite each other and are clamped together on the axle body 9. The assembly of axle seat portions 43, 44 and axle body 9 is clamped together by a pair of U-bolts 8. Also other trailing arms are possible, for example a trailing arm in one piece as is shown in Fig 12, which has an axle attachment zone 45 where an axle body can be attached to the trailing arm. As is visible in Fig. 3, the pivot bolt 5 has a shaft 52 and a head 51 on one end of the shaft 52. Furthermore the shaft 52 has a threaded portion 53 at another end of the shaft 52, which can cooperate with a threaded tightening nut 7.

The leading end 41 of the trailing arm 4 is formed as an eyelet, in which a bearing bushing 10 is arranged. The bearing bushing 10 comprises an inner metal bushing 11 and an outer elastic outer layer 12, which may be made of rubber. The outer bushing 12 is coaxial with the inner bushing 11, as is shown in Fig. 3, and may be vulcanized on the metal inner bushing. The elastic outer bushing 12 is in contact with the eyelet of the trailing arm 4. The metal inner bushing 11 extends in the axial direction of the bearing bushing 10 beyond the outer bushing 12 and the edges of the eyelet (cf. Fig. 3). In this way, when the leading end 41 of the trailing arm 4, assembled with the bearing bushing 10, is arranged between the side plates 21 of the bearing bracket 2, only the ends of the inner bushing 11 will engage the inner side of the side plates 21. In this particular embodiment, there are arranged washer rings 13 between the ends of the inner bushing 11 and the side plates 21, but these washer rings 13 may be omitted in other embodiments. The leading end 41 of the trailing arm 4 is pivotally attached to the bearing bracket 2 by aligining the inner bushing 11 with the holes 22 in the side plates 21 of the bearing bracket 2 and inserting the shaft 51 of the pivot bolt 5 through the holes 22, the washers 13 and the inner bushing 11, after which the nut 7 can be screwed on the threaded end of the bolt 5. The bolt shaft 51 has a diameter which accurately fits in the metal inner bushing 11. The diameter of the shaft 51 is slightly smaller than the inner diameter of the inner bushing 11, in practice this may be 0,1 mm of play, such that the shaft 51 can be fitted through the inner bushing 11 , but during use the bolt shaft is in contact with the inner side of the inner bushing 11. By tightening the nut 7 the inner bushing 11 is clamped between the side plates 21 and the washers 13. The pivotal movement of the leading end 41 of the trailing arm 4 is allowed by the elastic (rubber) bushing 12, which allows a rotation of the eyelet relative to the fixed inner bushing 11. The elastic outer bushing 12 also absorbs transverse loads from the trailing arm 4.

An eccentric disc 14 is arranged on an outer side of the respective side plates 21 of the bearing bracket 2. The eccentric disc 14 is provided with a bolt opening 15, through which the shaft 51 of the pivot bolt 5 extends. Thus, the shaft 51 of the pivot bolt 5 extends through the elongate holes 22 of the side plates 21, the leading end 41 of the trailing arm 4, and the bolt opening 15 of the eccentric discs 14. The eccentric disc 14 is for adjustment of the position of the pivot bolt 5 in the adjustment direction, which is the longitudinal direction of the slotted hole 22 and which is substantially parallel to the longitudinal direction of the vehicle. The side plate 21 is provided with protrusions 23, in the specific embodiment shown in Fig.1 with two protrusions 23, that are arranged at a distance from opposite ends of the elongate hole 22 such that an outer contour 14A of the eccentric disc 14 engages the protrusions 23 while rotating about the pivot axis. The eccentric disc 14 is essentially an eccentric cam with a circular outer contour. The protrusions 23 may for example be stamped in the side plate 21. Fig. 4A to Fig. 4C illustrates how the adjustment works. Fig. 4B shows the center position of the bolt shaft 51 in the elongate hole 22. By rotating the eccentric disc 14 clockwise (cf. Fig. 14A), the distance between the eccentric hole 15 in the eccentric disc 14 and the right protrusion 23 increases whereby the disc 14 moves to the left. The eccentric disc 14 rotates with respect to the bolt shaft 51, but also carries along said shaft 51 towards the left. By rotating the eccentric disc 14 counterclockwise (cf. Fig. 14C), the distance between the eccentric hole 15 in the eccentric disc 14 and the left protrusion 23 increases, whereby the hole 15 in the eccentric disc 14 moves to the left. The eccentric disc 14 rotates with respect to the bolt shaft 51 , but also carries said shaft 51 along towards the right. Thus, by rotatably adjusting the eccentric disc 14 a certain degree, the position of the bolt shaft 51 in the elongate hole 22 can be adjusted. Thus the trailing arms 4 can be aligned such that the wheel axle body 9 is perpendicular to the longitudinal direction.

The eccentric disc can be rotated with a tool. The eccentric disc 14 is provided with a recess 14B in the outer contour 14A such that the tool can engage the disc and the angular position of the disc 14 can be adjusted (cf. Fig. 4A to Fig. 4C). In a practical embodiment the outer contour 14A of the eccentric disc 14 has a diameter of 65 mm.

The pivot bolt 5 has a bolt shaft 51 with on opposite sides a flat abutment surface 54 that extends at least partially along a length of the shaft 51. The shaft 51 is mounted with said abutment surface 54 in the elongate holes 22, and with the abutment surface 54 parallel to the upper edge surface 22A and lower edge surface 22B of the at least one elongate hole 22.

The shaft 51 may have a cylindrical base shape with two opposite flattened abutment surfaces 54, such as is shown in Fig. 5A and Fig. 5B. The practical embodiment of the pivot bolt 5 that is shown in Figs 5A and 5B has a shaft diameter of 26 mm. The distance between the flat surfaces is 24 mm. The width is of the flat surface is about 10 mm, which is wide enough to prevent inadvertent rotation of the shaft 51 in the slotted hole 22. The threaded portion has a M24 thread.

However it is also possible that the shaft has a hexagonal shape as is shown in Fig. 6A and

Fig. 6B, or a square shape as is shown in Fig. 7A and Fig. 7B. The pivot bolts 5 of Fig. 5-7 have an abutment surface 54 over an entire length between the threaded portion 53 and the bolt head 52.

In other embodiments, which are shown in Figs 8-11 the shaft may have one or two longitudinal sections which have a flat abutment surface 54.

In the embodiment of Fig. 10A and 10B the mentioned sections are corresponding to the position of the elongate holes 22 in the side plates 21 in the mounted position of the bolt 5. The abutment surfaces 54 are thus spaced apart along the length of the shaft 51 , each of the abutment surfaces 54 being in engagement with the respective upper or lower edge surface of one of the elongate holes 22 in the side plates 21. The pivot bolt 5 has has at the spaced apart abutment surfaces 54 an identical outer diameter. In the embodiment shown in Fig. 10B the shaft has a central portion 55 defined between the spaced apart abutment surfaces 54. The central portion 55 has a diameter which is equal to or smaller than an outer diameter of the shaft 51 at the abutment surfaces 54.

The embodiments of Figs 8A, 8B, 9A, 9B, 11A and 11 B have only one longitudinal section with a flat abutment surface 54, either adjacent the head 52 (Fig. 9A, 9B and Fig. 11 A, 11 B), or adjacent the threaded portion 53 of the shaft 51 (Fig. 8A, 8B)

During assembly the nut 7 may be screwed on the bolt 5 but not yet tightened. In this state the eccentric discs 14 can be used to position the pivot bolt 5 in the elongate holes 22 in the side plates 21 of the bearing bracket 2. When the desired position of the pivot bolt 5 is set, the assembly can be fixed by tightening the nut 7 and pivot bolt 5 combination. Thereby the eccentric discs 14 are clamped between the side plates 21 and the head 52 and/or tensioning nut 7 of the pivot bolt 5, and the eccentric discs 14 are prevented from rotating.

By tightening the nut 7 and bolt 5 combination, the inner bushing 11 is clamped between the side plates 21 and the washers 13. A part of the vertical load is transferred from the trailing arm 4 to the bearing bracket 2 by the friction between the head surfaces of the inner bushing 11 and the washers 13 and the side plates 21. Another part of the vertical load is transferred from the trailing arm 4 to the bearing bracket 2 via the inner bushing 11 that is in contact with the bolt shaft 51 of the pivot bolt 5 and via the abutment between the abutment surfaces 54 of the pivot bolt 5 and the straight edges of the elongate holes 22 in the side plates 21 of the bearing bracket 2. Vertical loads originate from the trailing arm 4 and are thus transferred partially through the bearing bushing 10 onto the pivot bolt 5, and through the pivot bolt 5 directly onto the bearing bracket 2. The surface to surface engagement between the straight longitudinal edges of the elongate hole(s) 22 and the flat surface or surfaces 54 thus enables such a vertical load to be distributed from the trailing arm 4 on the bearing bracket 2 along the respective edge surface of the elongate hole 22. As the vertical load is distributed over a surface portion of the edge surface, instead of at a point (which would be the case with a fully round bolt shaft), local peak pressures can be prevented. This e.g. reduces risk of damage to the bearing bracket 2 and/or enhance the life expectancy of the bearing assembly. Moreover, the wheel axle suspension bearing assembly may be utilised for heavier uses. Also it allows side plates 21 of the bearing assembly to be manufactured of lighter and/or thinner plate material, which reduces material use and thus costs and results ultimately in a lighter vehicle.

In Fig. 12 another embodiment of a bearing assembly according to the invention is shown. The bearing assembly includes a bearing bracket 2 to be attached to a chassis beam of a vehicle chassis (cf. Fig.1 ) . The bearing bracket 2 comprises a pair of side plates 21 which are opposite each other and spaced apart. The side plates 21 each have an aperture 22 to pass through a pivot bolt 5. The apertures 22 of the respective side plates 21 are in line with each other, seen in a transverse direction of the vehicle. A trailing arm 4 has a leading end 41, which is positioned between the side plates 21 of the bearing bracket 2. The leading end 41 of the trailing arm 4 is pivotally attached to the bearing bracket 2 by the pivot bolt 5 extending through the leading end 41 and through the apertures 22 in the side plates 21 of the bearing bracket 2. An eccentric disc 14 is arranged on an outer side of the respective side plates 21 of the bearing bracket 2. The eccentric disc 14 is provided with a bolt opening 15, through which the shaft 51 of the pivot bolt 5 extends. Washer rings 13 are arranged on the inner sides of the side plates 21 in line with the openings 22.

Between the washer rings 13 the inner bushing 11 of the bearing bushing 10 of the trailing arm 4 is arranged. The leading end 41 of the trailing arm 4 is pivotally attached to the bearing bracket 2 by aligining the inner bushing 11 with the holes 22 in the side plates 21 of the bearing bracket 2 and inserting the shaft 51 of the pivot bolt 5 through the holes 22, the washers 13, the eccentric discs 14 and the inner bushing 11 , after which the nut 7 can be screwed on the threaded end of the bolt 5. By tightening the nut 7 the inner bushing 11 is clamped between the side plates 21 and the washers 13.

On the outer side of the inner side plate 21 of the bearing bracket a strut attachment collar 17 is welded. The strut attachment collar 17 has a circular annular base 18 that is positioned against the side plate and surrounds the opening 22. The strut attachment collar 17 furthermore comprises an overhang structure 19, which has a chassis facing, and thus in use upwardly facing, surface portion where a strut beam 50 is attached, in this case welded to the overhang structure 19.

The annular base 18 has a circular outer contour, and a circular inner contour. An eccentric disc 14 is arranged within said circular inner contour of the annular base 18. Another eccentric disc 14’ is arranged on an outer side of the opposite side plate 21. The eccentric discs 14 and 14’ have a hole 15 through which the pivot bolt 5 extends. The position of the pivot bolt 5 in the slotted hole 22 is adjustable by rotation of the eccentric discs 14, 14’. Thereby the longitudinal position of the leading end 41 of the trailing arm 4 and therefore of the trailing arm 4 as a whole can be adjusted. This allows to align the axle body with respect to the chassis. The circular inner contour of the collar 17 delimits the movement of the eccentric disc 14 to a rotation. The slotted shape of the apertures 22 then allow a degree of movement to the bolt 5 that extends through the hole 15 in the eccentric disc 14.

The hole 15 in the eccentric disc 14 in Fig. 12 may be a slotted hole or a round hole.

In a possible embodiment the eccentric disc 14 has an outer diameter which accurately fits within the circular inner contour of the annular base 18, such that the eccentric disc 14 can rotate within annular base 18. The centre of the annular base 18 is positioned above the centre of the opening 22 for the pivot bolt in the side wall 21. The distance between the two centres may be about 5mm, which allows that the eccentric disc 14 can be rotationally adjusted within the inner contour of the annular base 18. In such an embodiment the hole 15 in the eccentric disc 14 is an elongate hole or slotted hole to provide a degree of freedom for the pivot bolt 5 to shift.

In another embodiment the outer diameter of the eccentric disc 14 is smaller than the inner contour of the annular base 18. Then an additional protrusion can be arranged in the inner contour of the annular base. In the latter embodiment the hole 15 may be round with a slightly larger diameter than the shaft of the pivot bolt.