EP1831038A1

EP1831038A1 - Suspension for a vehicle

Info

Publication number: EP1831038A1
Application number: EP04806540A
Authority: EP
Inventors: Stéphane Brun
Original assignee: Renault Trucks SAS
Current assignee: Renault Trucks SAS
Priority date: 2004-12-21
Filing date: 2004-12-21
Publication date: 2007-09-12
Also published as: WO2006067551A1

Abstract

The present invention concerns essentially a suspension for motorized industrial vehicle that may be interposed between a chassis of the vehicle and an axle system of the vehicle. The suspension comprises two parallel longitudinal arms (2) having a first end (2a) and a second end (2b). The two arms (2) are rigidly connected by a transverse beam (3) thus forming an H-shaped element with the latter. Each end of the beam is embedded in one of the arms between the means of securing an axle system and the connection member. An important feature of the invention lies in the fact that an H-shaped element, which has considerable rigidity to twisting and a considerable transverse rigidity constitutes the basis of the suspension upon which suspension components can be grafted.

Description

SUSPENSION FOR A VEHICLE

Field of the invention

The invention concerns a rear suspension for a motorized vehicle , in particular industrial vehicles of the heavy goods lorry type .

Technological background

(As a preliminary, it is stated that reference will hereafter be made to the reference system X Y Z relating to the centre of gravity of the vehicle in which X is the longitudinal axis , Y is the transverse axis and Z is the vertical axis) .

A suspension is generally the mechanical member which provides the link between a vehicle chassis and an axle system (motorized axle or non-motorized axle) .

In the field of industrial vehicles used for the transport of merchandise whose total load weight is usually greater than 3.5 tonnes , it is known to fit the rear axle or axles of the vehicle with a suspension incorporating air cushions . These air cushions , thanks to a pneumatic control , are used to regulate the height of the chassis relative to the ground .

This disposition is extremely useful in at least two cases . Specifically, it allows a tractor vehicle to hitch trailers or semi-trailers whose hitching members are at different heights and also, in the case of a vehicle intended to load a container, it allows the height of the chassis to be adjusted according to the height at which the container is positioned .

In addition to the possibility of adjusting its vertical clearance , a suspension must of course satisfy the usual requirements , that is to say allow the wheels connected to the suspension to perfectly follow the profile of the ground in order to ensure constant adhesion, and filter out the vibrations and oscillations of which the wheels are the seat in order to protect the mechanical elements and the merchandise transported.

A specific problem that must be mentioned concerning vehicles fitted with a pneumatic suspension is that , when a vertical movement of the chassis is required along the Z axis obtained by changing the pneumatic pressure of the air cushions, this movement may induce a translation of the chassis along the X axis .

It therefore appears that improvements are desirable in the field of adjustable height pneumatic suspensions .

Summary of the invention

One obj ect of the invention is to propose a rigid suspension.

A further obj ect of the invention is to propose suspension for a motorized vehicle that can be used to adjust the vertical height of a chassis without inducing substantial longitudinal movement of the chassis and without inducing transverse movement of the chassis .

A further obj ect of the invention is to propose a suspension offering high quality transverse guidance .

A further obj ect of the invention is to propose a suspension that can be easily programmed according to the purpose of the vehicle to which it is fitted.

A further obj ect of the invention is to propose a suspension having compact dimensions . A further obj ect of the invention is to propose a suspension that can be installed in place of an existing suspension.

The present invention concerns essentially a suspension for a motorized industrial vehicle that may be interposed between a chassis of the vehicle and an axle system of the vehicle . The suspension comprises two parallel longitudinal arms having each a first end and a second end. Each arm supports at its first end, a connection member that can provide a link with the chassis , and at its second end, an elastic element of adjustable height that can be connected to the chassis . The suspension also comprises means of receiving and of securing the axle system on the parallel arms . The two arms are rigidly connected by a transverse beam thus forming an H-shaped element with the latter . Each end of the beam is embedded in one of the arms between the means of securing an axle system and the connection member . The suspension also comprises absorbing means which absorb the traction and/or braking forces received by the axle system. The absorbing means extend between the axle system and the chassis , at least substantially in a parallel to the arms . The essential feature of the invention lies in the fact that an H- shaped element constitutes the basis of the suspension upon which suspension components can be grafted .

In one embodiment , the means of absorbing the traction and/or braking forces can comprise a U-shaped stabilizer bar comprising a transverse portion and two longitudinal branches . Each of the longitudinal branches can be connected to the axle system, while the transverse portion can be connected to the chassis by two supports . The presence of a stabilizer bar means that the suspension, in this embodiment , is rather intended for a vehicle of substantial tonnage .

The stabilizer bar extends between the axle system and the chassis . In an embodiment , the stabilizer bar can advantageously be connected onto the axle system by two U sections capable of being secured onto the axle system. Each of the two U sections can pivotally attach the free end of the longitudinal branches of the stabilizer bar . The transverse portion of the stabilizer bar can be attached, at least pivotally, onto the chassis by two supports , in the vicinity of the connection brackets .

In a further embodiment , the means of absorbing the traction and/or braking forces can comprise two connecting rods each linking the axle system to the chassis . In this case, the vehicle fitted with a suspension according to this configuration would rather be a vehicle of low tonnage , for example between 7.5 tonnes and 11 tonnes per axle .

Preferably, each of the connecting rods can be provided with, at one of their ends , an attachment flange pivotally connectable to the axle system and with, at their second end, a flange pivotally connectable to the chassis in the vicinity of the connection bracket .

To provide the rigidity of the H-shaped element , the transverse beam can be connected to each of the arms via an embedding connection. The embedding could be of the ribbed, keyed or shrink-fit type .

To allow the height adjustment of the suspension, the adjustable-height elastic elements can be two air cushions formed by an elastic envelope containing a fluid whose pressure can be regulated.

Due to the forces , particularly twisting forces , which the transverse beam must absorb, the transverse beam is suitably made of spring steel .

If mechanical members should interfere with the transverse beam, the transverse beam is suitably provided with a local recess . This may be extremely useful for allowing a transmission shaft to pass through, for example .

In a further embodiment , the arms and the transverse beam could also be made of a single piece .

( The basis of the invention is therefore an H-shaped element that has great rigidity. Onto this H-shaped element , which provides a great rigidity to twisting and bending, components according to several embodiments are grafted .

The nature of the transverse beam contributes considerably to the general rigidity of the suspension and a change of this beam (different material , different dimension) may be used to greatly modulate the mechanical properties of the suspension to suit an application or a specific usage of the vehicle for which the suspension is intended .

It should be noted furthermore that , in all its embodiments , the suspension has a geometry which approximates a parallelogram whose bottom side would be an arm and the top side would be a branch of the stabilizer bar or a guide connecting rod. This geometry has the advantage that , when the height of the chassis relative to the ground is changed, the movement of the chassis in relation to the axle takes place along a virtually vertical component .

These and other advantages will become apparent upon reading the following description in view of the drawings attached hereto representing, as non-limiting examples , two embodiments of a suspension according to the invention.

Brief description of the drawings - S -

The following detailed description of embodiments of the invention is better understood when read in conjunction with the appended drawings being understood, however, that the invention is not limited to the specific embodiments disclosed . In the drawings :

Figure 1 represents in perspective a first embodiment of the invention . Figure 2 represents in perspective a second embodiment of the invention . Figure 3 shows the suspension according to the first embodiment attached to a vehicle chassis .

Detailed description of the invention

As a simplification, it should be noted that the elements that occur in both embodiments are identified by the same reference numbers .

As can be seen in each of the figures , the suspension in all its embodiments comprises two parallel arms 2 each having a first end 2a and a second end 2b . The arms 2 , which for example can be made of steel or forged aluminium, are particularly bulky and have a considerable inertia .

The two arms 2 are connected by a transverse beam 3. At each of its ends , the beam 3 is suitably engaged in an opening 4 for example circular made in each of the arms 2.

A point that is important to note is that the connections of the transverse beam 3 relative to the two arms 2 are connections of the embedding type , that is to say connections that allow no degree of freedom. These embedding links may be achieved in different ways , for example by the use of keys or ribbings . It is also possible to weld the two ends of the transverse 3 beam to each one of the arms 2.

Thus it can be seen that the basic body of the suspension is an H-shaped element consisting of the two arms 2 and the transverse beam 3.

Each of the arms 2 can receive , at one of its ends 2a, a connection bracket 6 to a chassis . The connection bracket 6 is , in the examples shown, a casting which, at one of its ends , can have a yoke 7 whose two arms have a bore for a shaft 8 to pass through. This yoke 7 is used to connect the connection bracket 6 to the end of each suspension arm 2. A transverse hole is in fact provided in the first end 2a of each arm 2. The connection between the connection bracket 6 and the suspension arm 2 can be achieved by engaging a shaft 8 in the bores provided in the yoke 7 and in the hole provided at the end of each arm 2. The hole made at the end of each of the arms can be fitted with a rubber bushing which gives certain rigidity to the connection.

It should be noted that the connection between each of the suspension arms 2 and the connection bracket 6 to the chassis can be considered as a ball and socket joint .

Each of the connection brackets 6 to the chassis also has holes 9 by which it is possible to attach them for example with pins or with bolts to each of the side rails 10 of a vehicle chassis , as is shown in Figure 3.

At their second end 2b, each of the arms 2 supports a suspension cushion 12. This suspension cushion 12 is of a well known type consisting of an elastic envelope which encloses pressurized air . These two cushions 12 are suitably connected to the pressurized air circuit of the vehicle .

The top face of each of these cushions 12 can be fitted with a L shaped section having one branch connected to the cushion 12 and a second perpendicular branch used for an attachment to the two side rails 10 of the chassis .

As the figures 1-3 show, the arms 2 can be hook-shaped at their second end 2b which allows each of the suspension cushions 12 to be vertically aligned with the side rails 10 forming the chassis , thus participating to a general compactness of the suspension.

Directly adj acent to the suspension cushion 12 , each of the arms 2 can have a pad 14 in which an eye is made which receives the bottom end of a shock absorber 15. The top end of this shock absorber 15 is attached to a side rail 10 of the chassis . Note that the shock absorber 15 is attached to the outer face of the side rail thus contributing to a large overall compactness of the suspension .

For the reception and attachment of a motorized or non-motorized axle, each of the arms 2 can be provided with a hole accepting a flange 16 having two branches with a bore . The flange 16 is attached, in the embodiment shown, by a bolt 17 engaged in each of the branches of the flange 16. In this flange 16 four apertures are made which receive two U-shaped clamps 18. The axle therefore comes between the clamps 18 and the flange 16 , the attachment of the axle being made by nuts which tighten the clamps 18 against the flange 16.

Depending on the architecture of a vehicle , a mechanical component such as a transmission shaft may interfere with the transverse beam 3. To obviate this inconvenience , the transverse beam 3 can be suitably provided with a local recess 22. The recess 3 can be obtained by machining and is thus carved in the transverse beam 3. The transverse beam 3 can also be shaped, for example by forging, to include a recess 22 which may be useful to avoid a conflict between the transverse beam 3 and a mechanical component .

In the embodiment shown in Figure 1 , a substantially U-shaped stabilizer bar 19 is provided . The stabilizer bar 19 can have two branches 20 oriented longitudinally relative to the suspension connected by a transverse portion 21.

To secure this stabilizer bar 19 , two U sections 23 can be provided, bolted to the axle, which each receive the free end of the longitudinal branches 20 of the stabilizer bar 19 allowing a pivot connection between the stabilizer bar 19 and the axle . The stabilizer bar 19 is moreover attached to each of the side rails 10 of the chassis by supports 25. In another embodiment , the stabilizer bar 19 could be coupled directly onto the connection brackets 6.

In the embodiment shown in Figure 1 , these supports 25 are in the shape of an L, one of whose branches is used for bolting onto each of the side rails 10 and the other branch is coupled to a bored portion .

This bored portion can receive a rubber bushing which provides a sliding pivot connection with the stabilizer bar 19 , this sliding pivot connection is nevertheless stiffened by the presence of the rubber bushing .

The embodiment shown in Figure 2 is distinct from the previously described embodiment in that the guidance of the motorized axle is provided by two connecting rods 27.

For the attachment of these connecting rods 27 , provision can be made at one of their ends for an attachment flange 29 connected to the axle and at their second end a flange 28 for attachment to each of the side rails 10 in the vicinity of the connection bracket 6. Each flange 28 provides a pivot j oint between each of the connecting rods 27 and the axle and each flange 29 provides a pivot joint between each of the connecting rods 27 and each of the side rails 10.

The consequences of the geometry of the suspension in the two embodiments previously indicated are extremely favourable on numerous points . Specifically, note first of all that this suspension behaves like a virtual parallelogram whose bottom side would be the arm 2 and the top side would be either the longitudinal branch 20 of the stabilizer bar 19 or a connecting rod 27.

The extremely favourable consequence of this arrangement is that , when the suspension cushions 12 are inflated or deflated depending on whether the requirement is to increase the height of the chassis relative to the ground or reduce the height of the chassis relative to the ground, the movement of the chassis relative to the axle occurs along a virtually vertical component .

It should also be emphasized that the fact that the transverse beam is situated in a position fairly close to the articulation of the arms relative to the connection bracket to the chassis means that the portion of the suspension adj acent to the members for connection to the chassis makes it possible to totally clear the space situated below the suspension cushions . This allows the use of extremely high cushions and so contributes to providing a suspension having a particularly great clearance .

It should also be noted, and this is one of the main advantages of the invention, that the fact that the suspension is based on a H-shaped element whose transversal beam 3 is embedded in the arms 2 between the connecting bracket 6 and the connecting flange 16 , contributes to giving the latter a considerable rigidity to twisting and a considerable transverse rigidity.

The suspension according to the invention may, furthermore , be easily adapted to different vehicles by varying the mechanical features or dimension of the transverse beam.

Naturally, the invention is not limited to the embodiments described above as non-limiting examples , but on the contrary it embraces all the embodiments and modifications within the scope of the appended patent claims .

Claims

1. Suspension for a motorized industrial vehicle intended to be interposed between a chassis of the vehicle and an axle system of the vehicle , the suspension comprising :

- two parallel longitudinal arms (2 ) each having a first end (2a) and a second end (2b) , each arm (2 ) supporting : - at its first end (2a) , a connection bracket (6) that can provide a link with the chassis ,

- at its second end (2b) , an elastic element of adjustable height that can be connected to the chassis ,

- securing means which can receive and secure the axle system to the parallel arms (2 ) , the two arms (2 ) being rigidly connected by a transverse beam (3 ) forming an H-shaped element with the latter, each end of the beam (3 ) being embedded in one of the arms (2) between the means of securing an axle system and the connection bracket (6) ,

- and absorbing means extending between the axle system and the chassis at least partly substantially in a parallel to the arms (2 ) , which absorb the traction and/or braking forces received by the axle system.

2. Suspension according to Claim 1 , characterized in that the absorbing means comprise a U-shaped stabilizer bar (19) having a transverse portion (21) and two longitudinal branches (20 ) which are substantially parallel the arms (2 ) , each of the longitudinal branches being connectable to the axle system, while the transverse portion (21) is connectable to the chassis by one or more supports (25) .

3. Suspension according to Claim 2 , characterized in that the stabilizer bar (19) is connectable onto the axle system by two U sections (23 ) capable of being secured onto the axle system, each of the two U sections pivotally attaching the free end of the longitudinal branches (20 ) of the stabilizer bar (19) .

4. Suspension according to Claim 2 or claim 3 , characterized in that the transverse portion (21) of the stabilizer bar (19) is capable of being attached, at least pivotally, onto the chassis by two supports (25) , in the vicinity of the connection brackets (6) .

5. Suspension according to Claim 1 , characterized in that absorbing means comprises two connecting rods (27) which are substantially parallel to the arms (2 ) each capable of linking the axle system to the chassis .

6. Suspension according to Claim 5 , characterized in each of the connecting rods (27) is provided with, at one of their ends , an attachment flange (29) pivotally connectable to the axle system and, at their second end, a flange (28) pivotally connectable to the chassis in the vicinity of the connection bracket 6.

7. Suspension according to one of Claims 1 to 6 , characterized in that the transverse beam (3 ) is connected to each of the arms (2) via an embedding connection.

8. Suspension according to one of Claims 1 to 7 , characterized in that the elastic elements with adjustable height consist of two air cushions (12) formed by an elastic envelope containing a fluid whose pressure can be regulated.

9. Suspension according to one of Claims 1 to 8 , characterized in that the transverse beam (3 ) is made of spring steel .

10. Suspension according to one of the Claims 1 to 9 , characterized in that the transverse beam (3 ) has a local recess (22) .

11. Suspension according to one of Claims 1 to 10 , characterized in that the arms (2 ) and the transverse beam (3 ) are formed of a single piece .