GB2223990A - Suspension for the rear wheels of a vehicle - Google Patents

Description

2,223 9 0, 0 PATENTS- ACT 1977 P599TGB/ALM/Mkf Description of Invention

"Suspension for the rear wheels of a vehicle" THIS INVENTION relates to a suspension for the undriven rear wheels of a motor vehicle.

German Patent Specification DE-PS 22 20 119. discloses a suspension comprising a compound axle linkage composed of a torsionally soft transverse strut and two somewhat S-shaped bent tubular longitudinal arms nondisplaceably and non-rotatably fixed to the transverse strut. Bearings are provided forwardly of the transverse strut for attaching the compound axle to the vehicle rhe free ends of the longitudinal arms directed chassis. 'L to the rear of the vehicle carry bearing blocks which also incorporate the axle journals. The sections of the bearing supports directed towards the centreline of the vehicle further serve as abutments for shook-absorbers with compression springs by which the bearing supports are spaced from the vehicle chassis.

A disadvantage of the known method of construction lies in the comparatively long lever arm between the transverse strut and the plane extending through the axle journals of the rear wheels, in which plane the abutments for the compression springs also lie. Because of this long lever arm the bearings in the forward regions of the transverse strut must be made correspondingly strong, so that the installation space available is constricted.

The abutments on the bearing supports forthe shook-absorbers and the compression springs lie somewhat below the axle journals. Thereby the region between the rear wheels with their wheel boxes and the transverse strut is considerably restricted by the space required by the compression springs and their upper abutments. The lever arm extending transversely between each longitudinal arm and the corresponding abutment is relatively long. Consequently, by directly integrating the bearing of the axle journals in the bearing supports, particularly in the case of impulsive spring loading by force transmitted from the compression springs to the bearing support, an additional torsional moment is applied to the longitudinal arms and thereby also to their direct connection with the transverse strut. This additional torsional moment moreover causes an increased tendency to negative inclination of the rear wheels with impulsive spring events and with high loading of the vehicle.

The present invention aims to reduce the requirements for the longitudinal arms and the bearings forwardly of t,ie transverse strut and also to provide a greater- installation space between the transverse strut and the longitudinal arms and the rear wheels.

Accordingly, the invention provides a suspension for the undriven rear wheels of a motor vehicle, which comprises two tubular longitudinal arms and a torsionally soft transverse strut non-displaceably and nonrotatably connected to the longitudinal arms, the ends of the longitudinal arms remote from the transverse strut being connected to bearing supports carrying axle journals and being held movably spaced from the vehicle body by shockabsorbing means including compression springs, in which suspension each bearing support is formed from a boxshaped axle journal support and a box-shaped spring support which lie next to one another with their transverse walls positively engaging at least about a third of the circumference of the associated longitudinal W W K) t.n C) In 0 C) to 'i " rn co cr l_i 0 W i-i CL n cr ct- " 0 ct, P) rj) F- 0 10 P) 0 cl (D (D 0 S-_ 10 (D 0 0 0 j 0 b- 0 (D 11 0 0 r CL 0 5 S-_ El 0 h- cr 0 ld (n co -i F-:3 E1 3.:1 FA 1-5 fl) "S::% (D -5 0 o Eg 5 W (n n -5 1-.:5 0q 10 - P) olq (D (D::5 0 " (D: 0 " (D I c (D j on 'I (D -:3 0 11 0 (D 11 IS C) $ Gq h- I- n 0q (D,:: 0. rt co,I cf- cl 0 cr (D -cl 'I U (D ct 0q (D Cl (n C-C W W (D (D to (D 3' (D 0 P) 0 ct- W (D 'i (D W l. tO (D - cf- 3' 10 m CL 10 t.,! 0 -5 (D 5 9 0q -j (n C-t- 'I I-- s 0 Ca '-,! W 1-0 (D CD W (D P) 0 0 (D 'I l- 'i -:j W c) (D 11 h- 0 (D f--j j 1- (D 1 5 b- cr:5 0 ct (D:;:$ ct. m 0 W 3 'ZJ:3 :r cr 0q 0 V 0,q (D c., (D (D o 0(D (D co D) ct W - 1,5 0q 11 0 " " 0 10 W 1.1 11 h'. Cr cr 0 CIP P3 15 [- 1:5 CL CD (D crW ; I's 0 l- bl co o y (_) W 0 cr- W " W 'i cr l-i " 1::s 3' l 0) W "S S f-- (D j 11 ct, t-t:3, E9 0 (D 0q 0 j (D o 11):j 0 0q j3, 0 0 "1 '(J (D ri) j r-,! 0q z " - co 1 0 n In. (D cr b- ct ct S_- 't. (D 0 11 (D 0 c-r- (D (}q 1-1 aq :,- 0 0 cl-(D (D cl- cf- 31 0 'D Y (D (D 'I ()q 0q 0 (D (D 1 (D (D (D (D cl j (D 1-1 (D:3, 0. (D fu 3 P. 0 aq ct, (D 0 C-t to ct C-t cf- (D n ct- ct. c.:g F- 0::3 co r -::r m I- (D 0 0 on (D 0' 0 y:j c-t- ct (D W (D:j (D o o ct, W 0 (D (D (D Cl. r_ 0 ct P) CL CL -- 5 g (D 0 (D -r F, P) n; (D cl- ct.

- 0 77 cr W Cr M 0 0 0q ER.1 0 03 15 'Cl 13) Q. F- (D W:j (D (D 0 > (D (D::S j (n (D cr 0q to (D 0q 3 0 (D W P) ct (D (D (D 0) 0 (D < (D 15 l. C"t (D C.C (n (D 'S (D (n (D 1--4:s orb 0 F-4 (D C-C W a rj) 0 0 10 3 0 0) = r_ I- a)- (D r- cf- cr cf, ci. p) W (D (D co CO (D 11 ct, rn 0q 0 15 "1 cf- ct, (D ct- W 9.1 T cr:3. Z j (D "r.,5 r (D (D (D a F-J F- (D (D y C[, cl. 'i :Y (D 0) 0q Ct. 0) fu 1ct-:g "S a 0q c- P) ct (D (D 0 (D a (D 11 15 rt 15 (D fl) 0 C.1:r 1- 0 F- (D (D -11r h- z (D 1 r 11 sz 1 ct 15:F 5Z 0 0 y C (D z m W re -b F- cr 1 0 c) 0 (D (D rt. 0.1 (D (D 0 C-C 7 l_i Z (D (D:y (D (D 0 j 1-5 0 1:E::j:T (D o 1 (D 'I rn Cr (D 0 (D cf, co y (D CL l. j W m co (n P) c) -S (D P) 0 j 0 C-t 0q (D:T (D (Er 0:5 0 (D (D 0 W l-b (D 0 W 0 C-t- (D 0 0q 0 0q a C) ct, J.1. (D ".I:J::3 (D W C-t. g P) cr " "1 0) 0 0 elf, F- s (D -l 11 F- " $= 0 0 (D s I- " 0) W or) El " W (D r, J (D 0 11 cl W 0 cl CO ct (D 0q " P) 0 - Z9 (-t ct '1 0 j 03 (D:3, '1 CL p) a,' 0q W P).13 (D 'I.i 11 (D rt-::r F- 3 0 1.1. 3 :i c 0 - 0q ort C-C &,. ce F E9 0 C-C j:3 (D J:3, 0q ct 0 cr:1 cl P) V '1 0 0 (D F-J:T F'.1:3, (D (D W::r ct [-. 0 (D M '3 P) F- (D:r 77 Y 0) (D (D 5 l Z5 co C.4 (D co aq (D 'S C)..5 (D to 10 'S 'S 10 cr In D- (D 9 (1) F- M Ul V 0 5 W 0q I- a rt(D f-- o cl 11 1--- (D:j (D W (D [_1 h- 0 D':1,-S 0 (D 0 1) 0 ct (-C F:r 0 (D 0 CC n (D 0 j 0q cf, S-- bi a F- 0 ::l: 0) ()q [1.

1 ct, SZ Q.

W F t W y 'i - Ll 0 pi 3 0q (D l 3 (D 'i (D cr 1-1 cf- s (1) :3 W (D -r ct- Ct. =1 (D n ct C-C 0 ct,:31 (D m w S S-- 10 0 "S 0 (D 'v " (D 0 1-5 cr, y (D 0) M F (D C.

0 (D (D (n 0:I In Izi l.

1 0q 1 W 1 direction of the longitudinal arm and also transverse to the latter lies in that an additional torsional moment on the longitudinal arm is avoided. Consequently, an eventual change in the inclination of the rear wheels is in practice determined only by the exactly computable stiffness of the transverse strut. Moreover, by this measure the installation space between the rear wheels and the transverse strut is further increased.

By " the box-shaped forming of the axle journal support and the spring support a high resistance to bending and torsion is achieved for a low input of material. The axle journal support and the spring support form in conjunction with the longitudinal arm a very compact unit which can withstand all external forces.

As a result of the fact that now both the axle journal support and the spring support are supported on the longitudinal arm in the longitudinal direction, the requirements for the entire composite axle are reduced. As the transverse walls of both supports positively engage the longitudinal arm at least over about a third of its circumference, disadvantageous stress points are largely avoided.

The weakening of the longitudinal arm by the depression is more than balanced by the box shape of the spring support. The spring support moreover forms a bridging member between the longitudinal sections of the longitudinal arm which are not modified. Thus by forming the box shape as desired an increase in the transferrable bending moments can be achieved straightaway.

On the basis of the measures proposed by the invention it is possible without any problem to arrange separately from one another a compression spring and a t damping cylinder. it is however, also possible to dispose a compression spring and damping cylinder concentrically to combine them into a shook- absorber.

The abutment for the compression spring is so formed that it perfectly centres the compression spring. In this regard a central pin of the abutment can be provided at its upper end with a buffer element which can become effective in the event of extreme compression of the spring.

The axle journal support and the spring support can be combined into one component. Preferably a simple sheet construction is used and is fabricated by drawing and/or bending and/or welding. However, preferably the spring support and axle journal support are manufactured separately in box form and are welded together and to the longitudinal arm. Another kind of connection is of course conceivable. In the separate manufacture of the axle journal support and spring support these components are equally preferably manu!"actured by drawing and/or bending and/or welding.

In view of the material and cost of the simple shaping of the axle journal support and the spring support, these components can be connected together by comparatively problem-free automatic welding procedures. Also, the welding seams can be located in regions which are favourable from the point of view of loading.

A possibility for modifying the longitudinal arm in the region of the spring support is working the arm without removal of material. In this, the longitudinal arm is flattened from above, in particular by a pressing operation, in correspondence to the longitudinal extent of the spring support and in this manner the desired depression is achieved. The transverse walls of the spring support however in any event still rest on the full cross-section of the longitudinal arm. A further advantage of forming without material removal is that the weakening of the resistance longitudinal arm with respect to bending and torsion is negligible compared to forming by machining involving the removal of material. It is more than balanced by the box-shaped spring support which acts as a bridging member.

If forming the longitudinal arm by materialremoving machining is used the desirable contour of the depression of the longitudinal link can be achieved by machining in a relatively simple and yet precise way.

The box like construction of the spring support is -he so compactly shaped that a lower positioning of 1.

spring abutment in the depression by at least half of the original cross-section of the tubular longitudinal arm is possible. As a result the upper abutment of the compression spring on the vehicle chassis can te disposed lower by this amount. In this manner additional passenger space or luggage space is won. Other cross sectional forms are however possible instead of a round longitudinal arm.

Preferably, the resultant of the force of the compression spring intersects the central axis of the longitudinal arm. This assures that the resulting spring force exerts no additional torsional moments on the longitudinal arm. The bend ing-resistant connection of the longitudinal arm to the torsionally soft transverse strut is thus not additionally loaded by a torsional moment resulting from the force of the spring. This mode of construction is particularly advantageous for vehicles with low tolerance to changes in the inclination of the undriven i rear wheels, since the sprinF force can cause no additional change of inclination by a torsional moment on the longitudinal arm. Any change of inclination then result mainly from the bending and/or torsional stiffness of the transverse strut, caused by the transmission of force to the base point of the wheel.

Integral forming of the spring support and abutment simplifies manufacture. However, such a weight saving frame construction offers a sufficiently large resistance to the bending and twisting resulting from the ^ the perpendicularly extending spring force on account of walls and their height.

An embodiment is however possible where the abutment is connected, and particular welded, to the box shaped spring support as a separately manufactured component.

In order that the invention may be more readi'-y understood, an embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a bearing support of a composite axle penetrated by a longitudinal arm of the axle; Figure 2 shows the arrangement of Figure 1 in plan view together with a rear wheel and a part of a transverse strut; and Figure 3 is a view of the arrangement of Figure 2 in the direction of the arrow III.

In Figures 1 to 3 there is shown a circular tubular longitudinal arm 1 of a composite axle not shown in more i 5 - longitudinal arm I is detail. The light S-shaped bent connected across the middle of the vehicle to a longitudinal arm arranged in mirror image fashion on the other side of the vehicle by a torsionally soft transverse strut 2 (Figure 2) in a bending-and torsionresistant manner.

The end 7 of the longitudinal arm 1 remote from the transverse strut 2 extends through a box-shaped axle journal support 3 for a rear wheel 19. The axle journal support 3 is folded from a stamped out blank. A bearing plate 4 is welded to the front of the side walls 5, 6 of the axle journal support 3. The side walls 5, 6 positively engage the section 7 of the longitudinal arm 1 over substantially its entire circumference. Side walls 5, 6 and the section 7 of the arm 1 are welded together.

The S-shaped displacement section 8 of the longitudinal arm 1 is, as particularly seen from Figures 1 and 3, provided with a depression 9 which corresponds to about half of the cross-section of the longitudinal arm 1. The depression 9 can be formed by working the arm 1 without removal of the material or by material-removing machining of the arm.

It is further apparent from Figures 1 to 3 that the displacement section 8 of the longitudinal arm 1 is bridged by a spring support 10 which is equally constructed in the form of a box. The transverse walls 11, 12 of the spring support 10 positively engage the longitudinal arm 1 over substantially the whole circumference, like the transverse walls 5, 6 of the axle journal support 3. The transverse walls 11, 12 are welded to the longitudinal arm 1. Further, the axle journal support 3 and spring support 10 are welded to one another.

1 The upper side of the spring support 10 is formed as a dish of annular shape, so that this dish 13 is adapted to the contour of the depression 9 in the longitudinal arm 1. A central pin 14 co-axial with the dish 13 can if desired be provided with a buffer element 15 (Figure 1).

The annular dish 13 forms an abutment for a compression spring 16 which presses at its other end against the vehicle chassis which is not illustrated. In particular, Figures 1 and 2 disclosed in this connection that the resultant 17 of the force of the compression spring 16 intersects the central axis 18 of the longitudinal arm 1.

Claims (10)

CLAIMIS:

1. A suspension for the undriven rear wheels of a motor vehicle, which comprises two tubular longitudinal arms and a torsionally soft transverse strut non displaceably and non-rotatably connected to the longitudinal arms, the ends of the longitudinal arms remote from the transverse strut being connected to bearing supports carrying axle journals and being held movably spaced from the vehicle body by shock-absorbing means including compression springs, in which suspension - is formed from a box-shaped axle each bearing Support journal support and a box-shaped spring support which lie next to one another with their transverse walls positively engaging at least about a third of the circumference of the associated longitudinal arm whereby the abutment for the compression spring, which is - in the arranged next to the axle journal support longitudinal direction of the longitudinal arm is located in a depression of the longitudinal arm.

2. A SUSDension according to claim 1, wherein the axle journal support, the spring support and the longitudinal arm are welded to one another.

3. A suspension according to claim 1 or 2, wherein the depression is formed by working the longitudinal arm without removal of the material.

4. A suspension according to claim 1 or 2, wherein the depression is formed by material-removing, machining the longitudinal arm.

5. A suspension according to any one of claims 1, to 4, - least about half of wherein the depression amounts to at bhe cross-section of the circular longitudinal arm.

6. A suspension according to any preceding claim, wherein the resultant of the force of the compression spring intersects the central axis of the longitudinal arm.

7. A suspension according to any preceding claim, wherein an abutment for the compression spring forms an integral dish-shaped part of the spring support which is formed from a sheet material.

8. A suspension according to any one of claims 1 to 6, wherein an abutment for the compression spring constitutes a part of a dish-shaped insert which is fixed to the upper longitudinal edges of the walls of the spring support.

g. A suspension for the undriven rear wheels of a motor vehicle substantially as hereinbefore described.

10. 8ny novel feature or combination of feature described herein.

S Published 1990 at The Patent Office. State House, 66 71 High Holborn, London WC1R4TP- Parther copies maybe obtained from The Patent Office Sales Branch. St IIaT:,, Crky. Orpington, Kent ERB 3RD- Printed by Multiplex techniques ltd. St Mary Cray. Kent. Con. 1 87