GB2308830A

GB2308830A - Air suspension system with safety feature against fracture of the trailing arm

Info

Publication number: GB2308830A
Application number: GB9700067A
Authority: GB
Inventors: Derk Geert Aalderink
Original assignee: Weweler NV; Weweler Nederland BV
Current assignee: Weweler NV; Weweler Nederland BV
Priority date: 1996-01-04
Filing date: 1997-01-03
Publication date: 1997-07-09
Anticipated expiration: 2017-01-03
Also published as: GB9700067D0; DE29700060U1; NL1002022C2; GB2308830B

Description

Air suspension system with safety feature against fracture of the tr2ilinc arm The present invention relates to an air suspension system for a road vehicle comprising an axle with a trailing arm close to each end, which trailing arms are each mounted on a suspension bracket which is joined to the frame Os the road vehicle, as well as a bellows between trailing arm and frame, wherein an auxiliary element is located close to each trailing arm, which auxiliary element is joined at one end to a component rigidly mounted on the frame and at the other end to the axle or axle clamp.

Air suspension systems of this type are used in lorries, buses and the like. The spring action, of such a system is based on the compressibility of the bellows joined to the trailing arms. Said trailing arms are constructed such th. at thev stabilise the rollin movement of the vehicle. In crder to se able to absorb the associated high bending s@resses in a suitable manner, the trailing arms are subjected to a heat treatment. A surface treatment is also carried out in order to prevent the occurrence of cracks.

If fracture of the trailing arms should nevertheless occur, the axle can no longer be held in its place, which can lead to hazardous situations. It is known to use a me auxiliary element as a safety device for the axle. The disadvantage of this is that a. metal auxiliary element of this type is exposed to fatigue because it is subjected to the same de, ormation as the trailing arm. Moreover, it can generate rattling noises ; the weight is relatively high.

The aim of the invention is to provide an air suspension system cX the abovementioned type which better meets the requirements. This is achieved in that the auxiliary element is a belt of supple material.

If a fracture of a trailing arm occurs with the air suspension system according to the invention, the axle can still be held more or less in its place by the auxiliary element. Risk and damage to the vehicle thus remain restricted.

The auxiliary element can be constructed in man y-differen. ways and d can also be attached in diverse ways, on condition that the auxiliary element always provides a connection between axle and vehicle frame. A first possibility Mhich may be mentioned is an embodiment according to which the auxiliary element is in belt form and is clamped at one end in the axle clamp. A belt of this type can be in loop form and clamped with both its ends in the axle clamp.

A metal belt cf this type has the disadvantage that it must be accurately manufactured ; rattling noises can also occur.

According to a first variant, the belt can be wrapped around the mounting for the trailing arm and elanped by its ends above and, respectively, below the trailing arm.

According to a second variant, the belt car. be clamped by both ends on the same side of the trailing arm and wrapped around d pin fixed to the suspension bracket.

As an alternative, in the latter case the belt, which is clamped by both ends on the same side of the trailing arm, can be wrapped around the mounting for the trailing arm and have its loop end wrapped around an element which functions in conjunction with the axle.

It would also be possible to wrap the loop end around a brake shaft, around the shock damper mounting at the axle clamp or around a clasp clamped in the axle clamp.

The auxiliary element preferably consists of a textile belt. Such a belt does not produce any troublesome ancillary noises.

The invention will be explained in more detail with reference to an illustrative embodiment shown in the figure.

The figure shcws part of an air suspension system according to the invention, comprising a suspension bracket 1, a spring arm 2 rotatably connected thereto by means of hinge pin 3, and a bellows 4. Suspension bracket 1 and the fitting 5 or bellows 4 are fixed to a frame, which is not further shown, of a vehicle.

The axle 6 is attached to the trailing arm 2 by means of U- bolts 7, clamping plate 8 and axle seating 9. which are known per se. A shock camper 17 also extends between the suspension bracket 1 and the trailing arm 2. As is known, an air suspension system of this tyre is located zt either end of the axle 6.

The trailing arm 2 is mada of a high grade steel, since it is exposed to severe flexural stresses when the lorry is in operaticn. Despite the high quality cf trailing arms 2 of this type, fracture does occur in said arns in a few cases. If said fracture is located between the point where the axle 6 is attached to the trailing arm 2 and the pin 3, dangerous situations can arise since the axle 6 is then no longer held in place.

To reduce this risk, the auxiliary element 10 in belt form is fitted in a first embodiment. Said auxiliary element in belt form consists of a flat belt, the two ends cf which can be seen at 11 and 12. Sa-~ ends are damped between the claming plate 6 and that part of the trailing arm 2 which faces said clamping plate. The belt is then wrapped around the rolled eye by means Oc whichthetrailingarm2ismounted on the pin 3, whilst the loop-shaped end 15 of the belt 1C is retained by means of a clasp 13. To this end the clasp is joined to a clamping plate 14, which, in turn, is clamped between the axle seating 9 and that part of the trailing arm 2 facing the latter.

The belt 10 thus forms a protection against fracture of the trailing arm 2. Moreover, the belt crotec-s both the undersurface and the top surface of the trailing arm 10 against dirt from the road which is thrown up, such as c=it, which would be able to damage the treated surface of the trailing arm 2.

In an alternative embodiment, the looc-shaped end 15 of the belt is wrapped around the brake shaft 16.

Claims

1. Air suspension system for a road vehicle eonprising-an axle with a trailing arm close to each end, which trailing armes are each mounted on a suspension bracket which is joined to the frame or the road vehicle, as well as a bellows between trailing arm and frame, wherein an auxiliary element is located close to each trailing arm, which auxiliary element is joined at one end to a component rigidly mounted on the frame and at the other end to the axle or axle clamp, characterised in that the auxiliary element is a belt of supple material.

2. System according to Claim 1, wherein the auxiliary element is clamped at one end in the axis clam ? and at the other end is attached to the suspension bracket.

3. System according to Claim 2, wherein the auxiliary element is loop-shaped and is clamped by both its ends in the axle clamp.

4. System according to Claim 3, wherein the belt is wrapped around the mounting for the trailing arm and is clamped by its ends above and, respectively, below the t--ailing arm.

5. System according to Claim 3, wherein the belt is clamped by both ends on the same side o the trailing arm and is wrapped around a pin fixed to the suspension bracket.

6. System according to Claim 3, wherein the belt is clamped by both ends on the same side of the trailing arm, is wrapped around the mounting for the trailing arm and d has its loop end d wrapped around an element which functions in conjunction with the axle.

7. System according to Claim 6, wherein the loop end is wrapped around a brake shaft.

8. System according tc Claim 6, wherein the loop end is wrapped around the shock damper mounting at the axle clamp.

9. System according to Claim 6, wherein the loop end is wrapped around a clasp clamped in the axle clamp.

10. System according to Claim 6, wherein the loop end is wrapped around a clasp joined to the U-bolts of the axle clamp.

11. System according to Claim 1, 2 or 3, wherein the auxiliary element is fixed to a clasp which is clamped in the axle clamp.

12. System according to one of the preceding claims, wherein the auxiliary element is a textile belt.

13. Air suspension system for a road vehicle substantially as described herein with reference to the accompanying drawing.

Claims An air suspension system for a road vehicle axle, said system comprising a trailing arm with first and second ends for supporting the axle, the first end of the trailing arm being pivotably mounted on a suspension bracket joined to the frame of the road vehicle, bellows mounted between the second end of the trailing arm and the frame and a belt of supple material which extends at least alongside the trailing arm at a region adjacent the first end and serves as an auxiliary support element for the axle in the event of fracture of the trailing arm.

2. A suspension system according to claim 1, wherein the belt extends around the first end of the trailing arm.

3. A suspension system according to claim 2, wherein a clamp serves to couple the axle to the trailing arm between the first and second ends and the belt has first and second ends fastened together and held on the clamp at one side of the trailing arm and a looped region remote from the first and second ends which is fixed to the clamp at another side of the trailing arm so that the belt extends along both sides of the trailing arm in two layers.

4 A suspension system according to claim I or 2, wherein a clamp serves to couple the axle to the trailing arm between the first and second ends and the belt has first and second ends fastened together and held on the clamp at one side of the trailing arm and a looped region remote from the first and second ends which extends around a fixed component separate to the clamp.

5. A suspension system according to claim 1 or 2, wherein a clamp serves to couple the axle to the trailing arm between the first and second ends and the belt has one end fastened to the clamp at one side of the trailing arm and another end attached to the suspension bracket.

6. A suspension system according to claim 2, wherein a clamp serves to couple the axle to the trailing arm between the first and second ends and the belt extends alongside opposite sides of the trailing arm between the first end of the trailing arm and the clamp and is fastened to the clamp.

7. A suspension system according to claim 1, wherein the belt is fixed at locations above and below the trailing arm and is looped around the first end of the trailing arm and its pivot mounting 8. A suspension system according to claim 1, wherein the belt extends alongside the trailing arm and around the first end of the trailing arm in two layers.

9. A suspension system according to claim 1 or 2, wherein the belt has first and second ends clamped together at a location at one side of the trailing arm and is wrapped around a pin fixed to the suspension bracket.

10. A suspension system according to claim 1, wherein the belt has first and second ends clamped together at a location at one side of the trailing arm, the belt extends around the pivot mounting of the trailing arm and part of the trailing arm adjacent the first end in a double layer and the belt has a looped region opposite the first and second ends wrapped around an element which functions in conjunction with the axle.

II A suspension system according to claim 10, wherein the looped end region is wrapped around a brake shaft.

12. A suspension system according to claim 10, wherein the looped end region is wrapped around a mounting connecting a shock damper to a clamp used to clamp the axle to the trailing arm.

13 A suspension system according to claim 10, wherein the looped end region is wrapped around a clasp fastened to a clamp used to clamp the axle to the trailing arm.

14. A suspension system according to claim 10, wherein the looped end region is wrapped around a clasp joined to U-bolts of a clamp used to clamp the axle to the trailing arm.

15. A suspension system according to claim I or 2, wherein the belt is fixed to a clasp which is fastened to a clamp used to clamp the axle to the trailing arm.

16. A suspension system according to any one or more of the preceding claims, wherein the belt is made from textile material.

17. An air suspension system for a road vehicle substantially as described herein with reference to the accompanying drawings.