WO2017142633A1

WO2017142633A1 - Bushing for beam-type axle suspension system

Info

Publication number: WO2017142633A1
Application number: PCT/US2017/000016
Authority: WO
Inventors: Neil HASLAM
Original assignee: Dexter Axle Company
Priority date: 2016-02-19
Filing date: 2017-02-21
Publication date: 2017-08-24

Abstract

A pivot bushing for a vehicle suspension has a metal core with a central opening which passes through the core. The metal core surrounds the central opening and has an oval shape with two opposing ends and two opposing sides. An elastic body surrounds the metal core. The elastic body is flexible and resilient and is thinner in an area of the two ends and thicker in an area of the two sides of the metal core. The greater thickness of the elastic body in the area of the two sides compared to the thickness in an area of the two ends causes the bushing to be more rigid in a direction of a horizontal plane through the two ends than it is in a direction of the vertical plane through the two sides when the vehicle suspension is subjected to horizontal and vertical loads when the bushing is installed in the mounting tube of the suspension.

Description

BUSHING FOR BEAM-TYPE AXLE SUSPENSION SYSTEM BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0001] This invention relates to axle suspension systems for wheeled vehicles and, in particular, to beam-type axle suspension systems for wheeled vehicles. More particularly, this invention is directed to a beam-type axle suspension system for tractor trailers in which each beam tapers from a narrow width at an end which is pivotally attached to a trailer frame without special mounting accessories and utilizes a reduced sized bushing.

DESCRIPTION OF THE PRIOR ART

[0002] Air-ride beam-type axle suspension systems are known in the heavy-duty truck-tractor trailer industry. Each system typically includes a pair of longitudinally extending beams and each beam is located adjacent to and below a respective one of a pair of spaced-apart longitudinally extended frame rails which depend from the trailer. Each beam is pivotally connected at one of its ends to a hanger which is attached and depends from a respective one of the frame rails. An axle extends transversely between and is mounted at or near an end of the beam opposite to the pivotal connection end. The pivotal connection end is connected to a bellows air spring or its equivalent which in turn is connected to a respective one of the trailer rails. Typically, a brake assembly and shock absorber is mounted on each of the beams. The beams may extend rearwardly or forwardly relative to a front end of the tractor trailer, thus defining a trailing arm or leading arm beam suspension system respectively. Air-ride beam-type axle suspension systems generally require a pivot bushing at the pivotal attachment point of each beam to the trailer frame rails for satisfactory reaction to static loads, roll movements and braking forces.

[0003] It is known to make pivot bushings more rigid in the direction of the horizontal plane than in the direction of the vertical plane when the vehicle suspension is subjected to a horizontal load and a vertical load respectively by the strategic location of the voids in an elastic body of the bushings. The voids weaken the elastic body in a direction of one plane. However, the useful life of the pivot bushings is reduced as the bushings tend to fail or tear prematurely at the location of the voids.

SUMMARY OF THE INVENTION [0004] It is an object of the present invention to provide a pivot bushing that exhibits satisfactory durability and reaction to static loads, roll movements, lateral forces and braking forces. There is one pivot bushing for each beam of a suspension and each bushing has a metal core with a central opening passing through the core. The metal core has two opposing ends and two opposing sides. The two opposing ends are further apart from one another than the two opposing sides are apart from one another. The metal core has a cross sectional oblong shape with rounded corners. The metal core is surrounded by a generally cylindrically shaped elastic body having a front and rear. The central opening has a longitudinal centre. The bushing is mounted in a mounting tube whereby the sides of the elastic body substantially fill the tube. A rigid sleeve is movably mounted in the central opening, the rigid sleeve having an outside diameter being generally equal to the central opening diameter, and extending substantially the entire width of the central opening to facilitate mounting of the bushing on a vehicle suspension.

[0005] A bushing for a vehicle suspension, the bushing comprising: a) a metal core having a central opening, which passes through the core, the metal core surrounding the central opening and being shaped to have two opposing ends and two opposing sides, the two opposing ends being further apart from one another than the two opposing sides are apart from one another, the metal core having a cross sectional oblong shape with rounded corners; b) an elastic body surrounding the oblong shape of the metal core and the central opening, the elastic body having a generally circular periphery and being made from a flexible and resilient material; and c) the elastic body being shallower in a first plane through the two ends than in a second plane through the two sides.

[0006] A pivot bushing for use in an air-ride beam-type axle suspension system comprises: a) a metal core having a central opening therein, the central opening extending through the core, said metal core surrounding the central opening and being shaped to have two opposing ends and two opposing sides, the two opposing ends being further apart from one another than the two opposing sides are apart from one another, the metal core having a cross sectional oblong shape with rounded corners, the two opposing ends being in a first plane that is substantially orthogonal to a second plane through the two opposing sides; b) an elastic body surrounding the oblong shape of the metal core and the central opening, the elastic body having a substantially circular periphery; and c) the elastic body being more rigid in the first plane through the two ends than in the second plane through the two sides, a longitudinal centre axis of the central opening being a horizontal pivot axis of the bushing.

[0007] The method of constructing a bushing for use in a vehicle suspension, the bushing having a metal surrounded by an elastic body, the metal core having a central opening therein. The method comprises constructing the metal core to have a cross sectional oblong shape with rounded corners, surrounding the oblong shape with an elastic body that is flexible and resilient, forming the elastic body to have a generally circular periphery.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a perspective view of a first embodiment of a bushing; [0009] Figure 2 is a front view of the bushing of Figure 1 ;

[0010] Figure 3 is a cross sectional view of the bushing through section A-A of Figure 2; [0011] Figure 4 is a sectional view through the section B-B of Figure 2;

[0012] Figure 5 is an end view of the bushing of Figure 1 oriented to correspond to the sectional view shown in Figure 3;

[0013] Figure 6 is a side view of the bushing of Figure 1 oriented to correspond to sectional view of Figure 4;

[0014] Figure 7 is a partial side view of a suspension with the bushing of Figure 1 mounted in a mounting tube;

[0015] Figure 8 is a perspective view of a beam-type axle suspension system using the bushing of the present invention;

[0016] Figure 9 is a partial perspective view of a suspension system between an axle and affixed to a trailer frame;

[0017] Figure 10 is a rear view of the suspension system affixed between the axle and the trailer frame; [0018] Figure 11 is a side view of the suspension system installed between the axle and the trailer frame;

[0019] Figure 12 is a front view of a second embodiment of a bushing; [0020] Figure 13 is a perspective view of the second embodiment of the bushing; [0021] Figure 14 is an end view of the second embodiment of the bushing; [0022] Figure 15 is a side view of the second embodiment of the bushing; [0023] Figure 16 is a front view of a third embodiment of a bushing; [0024] Figure 17 is a perspective view of the third embodiment of the bushing; [0025] Figure 18 is an end view of the third embodiment of the bushing; and [0026] Figure 19 is a side view of the third embodiment of the bushing. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0027] In Figures 1 to 4, a first embodiment of a bushing 2 has a metal core 4 with a central opening 6 passing through the metal core. The metal core 4 has a cross sectional oval shape 8. An elastic body 10 surrounds the oval shape 8, the elastic body having a first periphery 12. The bushing 2 has a front 14 and a rear 16 with central opening 6 extending through the metal core 4 between the front 14 and rear 16. The central opening has a longitudinal centre axis 18. The metal core 4 has a shorter cross sectional width (between the sides) along the A-A axis and a longer cross sectional length (between the ends) along the B-B axis. The elastic body 10 has greater depth along the A-A axis than along the B-B axis.

[0028] From Figures 3 to 6, it can be seen that the elastic body 10 is preferably narrower than the metal core 4 and has a second periphery 20 that corresponds to the shape of the metal core 4.

[0029] Since the elastic body 10 has a greater depth along the A-A axis than along the B-B axis, the elastic body 10 is more flexible along the A-A axis than along the B-B axis. An indicator 22 identifies the orientation of the B-B axis so that the proper orientation of the bushing 2 can be readily determined when the bushing is in use. [0030] Preferably, the elastic body 10 of the bushing 2 of the present invention does not contain any voids and is made from one material that is generally solid, but is flexible and resilient.

[0031] In Figure 7, a mounting tube 24, in which said bushing 2 is mounted, is sized to be substantially filled by said bushing. The mounting tube 24 is connected to a beam 26 of a suspension system (not shown in Figure 7). In Figures 5 and 6, it can be seen that there is a sleeve 28 mounted in said central opening, the sleeve being sized to fit tightly within said central opening 6 to enable the bushing to be mounted on the vehicle suspension. The longitudinal centre axis 18 (shown in Figure 3) provides a horizontal pivot axis for the bushing. The bushing 2 and the mounting tube 24 are sized relative to one another so that the bushing fits snugly into the mounting tube and completely fills the mounting tube. The central opening 6 extends from the front 14 to the rear 16 (see Figure 6).

[0032] Figure 8 is a perspective view of a suspension system having an axle 28 with two parallel beams 26, 32 of a suspension system connected thereto at ends 34, 36 respectively. Ends 38, 40 of beams 26, 32 respectively are located opposite to the ends 34, 36 and have the mounting plate mounting tube 24 connected thereto. There are two mounting tubes 24, one mounted in each beam 26, 32 and each mounting tube 24 has the bushing 2 inserted therein.

[0033] In Figures 9 to 11 , a suspension system 42 is connected between the axle 28 and the vehicle or trailer frame 44. The beams 26, 32 are affixed to the axle 28 at ends 34, 36 respectively. The opposite ends 38, 40 of the beams 26, 32 respectively each have a mounting tube 24 (not shown in Figures 9 to 11) that is pivotally mounted on hanger brackets 46 through pivots 48. There are pneumatic bellows 50 located between the beams 26, 32 and the vehicle or trailer frame 44. Shock absorbers 52 are connected between each of the beams 26, 32 and each of the hanger brackets 46.

[0034] In Figures 12 to 15, there is shown a further embodiment in which a bushing 54 has a metal core 56 that has a rectangular shape with rounded corners. The metal core 56 has the central opening 6 and is surrounded by an elastic body 58. The elastic body 58 has a substantially circular periphery 59. In Figure 14, it can be seen that the elastic body 58 is narrower than the metal core 56 and has a second periphery 60 that corresponds to the shape of the metal core 56. Figure 15 is a side view of the bushing 54. By comparing Figures 14 and 15, it can readily be seen that the elastic body 58 has a greater depth adjacent sides 62 of the metal core 56 than a depth of the elastic body 58 adjacent ends 64 of the metal core 56. The elastic body 58 will therefore be more flexible in an area adjacent the sides 62 and less flexible in an area adjacent the ends 64 of the metal core 56.

[0035] In Figures 16 to 19, there is shown a further embodiment in which a bushing 66 has a metal core 68 that has a generally hexagonal cross-sectional shape with rounded corners. The straight edges of the hexagonal shape are not equal in length. The metal core has two sides 70 and two ends 72. An elastic body 74 has a circular periphery 75 and surrounds the metal core 68. In Figures 18 and 19, it can be seen that the elastic body 74 is narrower than the metal core 68 and has a second periphery 76 that corresponds to the shape of the metal core 68. A depth of the elastic body adjacent the sides 70 is greater than the depth of the elastic body 74 adjacent the ends 72. The elastic body 74 will therefore have greater flexibility in an area adjacent the sides 70 of the metal core 68 than it does in area adjacent the ends 72. Preferably, the elastic body is made from rubber or similar flexible or resilient material and is still more preferably made from one material.

[0036] All of the cross-sectional shapes of the metal cores of all three bushings 2, 54, 56 have an oblong shape with rounded corners where the two opposing ends are further apart from one another than the two opposing sides are apart from one another. Additional oblong shapes of the bushing, within the scope of the claims, will also be suitable. For example, metal cores having an egg-shaped cross-sectional shape could be used. The elastic body of the bushing of the present invention preferably does not contain any voids. The indicator 22 shown on the bushing 2 is preferably located on all of the embodiments of the bushings. The indicator 22 identifies the orientation of the less flexible axis B-B, but the indicator could be relocated to identify the more flexible axis A-A of the bushing 2, or to identify a different orientation. Whatever location is chosen for the indicator, that location should be used consistently.

[0037] Since the bushing of the present invention does not have any voids, it is more durable and will last longer than bushings that contain voids in the elastic body to make the bushing more flexible in one direction compared to another direction. Bushings containing voids tend to fail at the voids due to the constant flexing of the material of the bushing at the voids. The shapes of the bushings 2, 56, 66 are preferred with the shape of the bushing 2 being the most preferred.

[0038] Variations within the scope of the attached claims will be readily apparent to those skilled in the art.

Claims

A pivot bushing for a vehicle suspension, the bushing comprising: a) a metal core having a central opening, which passes through the core, the metal core surrounding the central opening and being shaped to have two opposing ends and two opposing sides, the two opposing ends being further apart from one another than the two opposing sides are apart from one another, the metal core having a cross sectional oblong shape with rounded corners; b) an elastic body surrounding the oblong shape of the metal core and the central opening, the elastic body having a generally circular periphery and being made from a flexible and resilient material; and c) the elastic body being shallower in a first plane through the two ends than in a second plane through the two sides.

The pivot bushing as claimed in Claim 1 wherein the metal core has a cross sectional shape that is one selected from the group of oval, rectangular with rounded corners and generally hexagonal with rounded corners.

The pivot bushing as claimed in Claim 2 wherein the oval shape of the metal core is an elliptical shape.

The pivot bushing as claimed in Claim 1 wherein the elastic body has a shallower cross section in an area of the two ends of the metal core and a deeper cross section in an area of the two sides of the metal core.

The pivot bushing as claimed in Claim 3 wherein the elastic body is made from one material that is generally solid, but is flexible and resilient.

The pivot bushing as claimed in Claim 4 wherein the elastic body does not contain any voids.

The pivot bushing as claimed in Claim 1 wherein there is a mounting tube in which the bushing is mountable, the mounting tube being sized to be substantially filled by the bushing.

8. The pivot bushing as claimed in Claim 6 wherein there is a sleeve mounted in the central opening, the sleeve being sized to fit tightly within the central opening to enable the bushing to be mounted on an axle suspension.

9. The pivot bushing as claimed in Claim 1 wherein the metal core has a front and a rear and the central opening extends from the front to the rear, the elastic body having a front to rear width that is narrower than a front to rear width of the metal core.

10. The pivot bushing as claimed in Claim 1 wherein the elastic body is less flexible in the first plane than in the second plane.

11. A pivot bushing for use in air-ride beam-type axle suspension system comprising: a) a metal core having a central opening therein, the central opening extending through the core and having two opposing and two opposing sides, the two opposing ends being further apart from one another than the two opposing sides are apart from one another, the metal core having a cross sectional, oblong shape with rounded corners, the two opposing ends being in a first plane that is substantially orthogonal to a second plane extending through the two opposing sides; b) an elastic body surrounding the oblong shape of the metal core in the central opening, the elastic body have a substantially circular periphery; and c) the elastic body being more rigid in the first plane than in the second plane, a longitudinal centre axis of the central opening being a horizontal pivot axis of the bushing.

12. The pivot bushing as claimed in Claim 11 wherein the plastic body has a substantially lesser thickness in the first plane than in the second plane.

13. The pivot bushing as claimed in Claim 11 wherein the metal core has a cross sectional shape that is one selected from the group of oval, rectangular with rounded corners and generally hexagonal with rounded corners.

14. The pivot bushing as claimed in Claim 13 wherein the elastic body has a shallower cross section in an area of the two ends of the metal core and a deeper cross section in an area of the sides of the metal core.

15. The pivot bushing as claimed in Claim 14 wherein the elastic body is made from one material that is generally solid, but is flexible and resilient.

16. The pivot bushing as claimed in Claim 14 wherein there is a mounting tube in which the bushing is mountable, the mounting tube being sized to be substantially filled by the bushing.

17. The pivot bushing as claimed in Claim 14 wherein there is a sleeve mounted in the central opening, the sleeve being sized to fit tightly within the central opening to enable the bushing to be mounted on an axle suspension.

18. The pivot bushing as claimed in Claim 13 wherein the metal core has a front and a rear and the central opening extends from the front to the rear, the elastic body having a front to rear width that is narrower than a front to rear width of the metal core.

19. A method of constructing a pivot bushing for use in a vehicle suspension, the bushing having a metal core surrounded by an elastic body, the metal core having a central opening therein, the method comprising, constructing the metal core to have a cross sectional oblong shape with rounded corners, surrounding the oblong shape with an elastic body that is flexible and resilient, forming the elastic body to have a generally circular periphery.

20. The method as claimed in Claim 13 comprising the step of forming the elastic body to have an outer portion that is narrower than a width of the metal core.