GB2329163A - Independent suspension with a wheel carrier supported on a semi-trailing or semi-leading arm via a coupling rod - Google Patents

Abstract

A suspension for front wheels of a motor vehicle, having a wheel carrier 21 that can be pivoted for steering purposes, whose first and lower joint G is mounted on a semi-trailing or semi-leading arm 31 and whose second joint E, lying above the horizontal wheel centre plane, is connected to a coupling rod 41 that is supported in an articulated manner on the semi-trailing arm. The coupling rod 41 is extended upwards at least into the close proximity of the tyre running surface 3. At the end of the extension there is an articulation point C1, via which a tension strut 52 is supported on the vehicle front wall.

Description

Independent suspension with a wheel carrier supported on a semi-trailing arm via a coupling rod The invention relates to an independent suspension for front wheels of a motor vehicle, having a wheel carrier that can be pivoted for steering purposes, whose first and lower joint is mounted on a semi-trailing arm and whose second joint, lying above the horizontal wheel centre plane, is connected to a coupling rod that is supported in an articulated manner on the semi-trailing arm.

In car-body construction, the accident-induced, controllable deformation of the vehicle front construction has higher and higher requirements placed on it. Thus, attempts are made to configure the vehicle longitudinal chassis rails in such a way that they compress or deform as uniformly as possible, inter alia in crash tests. From this, it is possible to derive, for the construction of the front axle, the requirement to minimize the number of articulation points on the longitudinal chassis rail, which necessarily require stiffening there. As an alternative to the articulation on the longitudinal chassis rail, the articulation points of the links can be arranged on a transverse chassis rail or the front wall of the vehicle passenger compartments, preferably in the region of the longitudinal side sills.

A front axle which satisfies this requirement, with the exception of the articulation of a tension strut, is known from DE 26 42 939 C2. In the case of this space-saving independent suspension, the wheel carrier and the coupling rod form a double crank which stands on a semi-trailing arm and is mounted there such that it can pivot about an approximately horizontal axis. The wheel carrier is supported at its upper joint via a link, likewise running approximately horizontally, on the wheel arch or a longitudinal chassis rail of the vehicle superstructure. The link runs approximately at the level of the upper brake disc edge, obliquely in relation to the vehicle longitudinal axis. Because of the high link loading under braking operations, the supporting points are specially stiffened.

The present invention seeks to provide an independent suspension in which as few articulation points as possible are arranged on the longitudinal chassis rail and, in the event of a link being supported on the side of the front wall, relatively low forces act in the articulation points there, provided they are located outside the longitudinal side sill connection.

According to one aspect of the present invention there is provided an independent suspension for front wheels of a motor vehicle, having a wheel carrier that can be pivoted for steering purposes, whose first and lower joint is mounted on a semitrailing arm and whose second joint, lying above the horizontal wheel centre plane, is connected to a coupling rod that is supported in an articulated manner on the semitrailing arm, wherein the wheel carrier extends upwards at least into the close proximity of the tyre running surface, ends there in a joint on the imaginary wheel steering axis and is supported on the vehicle front wall via a tension strut.

In this case, the wheel carrier, which is mounted on a semi-trailing arm, is extended upwards at least into the close proximity of the tyre running surface. At the end of the extension there is an articulation point which lies on the imaginary wheel steering axis. From this articulation point, the wheel carrier is supported on the vehicle front wall via a tension strut.

According to a second aspect of the invention there is provided an independent suspension for front wheels of a motor vehicle, having a wheel carrier that can be pivoted for steering purposes, whose first and lower joint is mounted on a semitrailing arm and whose second joint, lying above the horizontal wheel centre plane, is, on the one hand, connected to a coupling rod that is supported in an articulated manner on the semi-trailing arm and, on the other hand, is connected in an articulated manner to the vehicle superstructure via a tension rod, wherein the coupling rod extends upwards at least into the close proximity of the tyre running surface, ends there in a joint on the imaginary extension of the path between the articulation on the semitrailing arm and the articulation on the wheel carrier and is supported on the vehicle front wall via the tension rod.

Furthermore, according to a third aspect, there is provided an independent suspension for front wheels of a motor vehicle, having a wheel carrier that can be pivoted for steering purposes, whose first and lower joint is mounted on a semi-trailing arm and whose second joint, lying above the horizontal wheel centre plane, is connected to a coupling rod that is supported in an articulated manner on the semi-trailing arm, wherein the coupling rod articulates between the articulation on the semi-trailing arm and the articulation on the wheel carrier, in an articulated manner on an element of a spring strut supporting the suspension on the vehicle superstructure, the lower end of the spring strut being supported on the semi-trailing arm, while the upper end is fastened in an articulated manner on the loadbearing wheel arch or the front wall.

In the case of the first two variants, either the wheel carrier or the coupling rod is preferably extended, for example by one and a half to two times its length. As a result, the tensile forces occurring in the tension strut or the tension rod are reduced by about 33 to 50% as compared with the construction from DE 26 42 939 C2, given approximately similar angular relationships. An articulation on the vehicle front wall is thus possible there without above-average stiffening.

The extensions can be configured, together with the wheel carrier or the coupling rod, for example as forged or sheet-metal parts. Their respective configuration is determined, inter alia, by the strength requirements and the space relationships.

In the case of the third variant, a tension strut is not needed. The double crank consisting of coupling rod and wheel carrier is supported on the spring strut of the front suspension. This independent suspension corresponds to a McPherson front axle, at least in relation to the spring strut, but without the longitudinal rotation of the damper and the springing when the steering is turned.

Further details of the invention emerge from the following description of several embodiments that are illustrated schematically in the accompanying drawings, in which: Figure 1: shows an independent suspension with extended wheel carrier; Figure 2: shows an independent suspension as in Figure 1 with a brake disc offset inwards, a large kingpin inclination and a large, negative steering rolling radius; Figure 3: shows an independent suspension as in Figure 2 with a small kingpin inclination and a small, negative steering rolling radius; Figure 4: shows an independent suspension as in Figure 1 with a brake disc seated on the outside and a semi-trailing arm, which is articulated on the wheel carrier via a track-rod arm; Figure 5: shows a partial side view relating to Figure 4; Figure 6: shows a partial plan view relating to Figures 4 and 5; Figure 7: shows an independent suspension with extended coupling rod; Figure 8: shows an independent suspension with the coupling rod supported on a spring strut.

Figures 1, 7 and 8 show three variants of an independent suspension, in which in each case only one joint is fastened to a longitudinal chassis rail. The righthand, front independent suspension with a steerable wheel 1 is illustrated - viewed in the direction of travel. The steering-arm gear is not drawn in these figures.

In order to recognize the schematic, three-dimensional illustration better, several auxiliary planes have been inserted in these figures. A first horizontal plane 11 lies at the level of the inner side of the rim of the wheel 1, which is illustrated in the straight-ahead position. Located in this plane is, for example, a longitudinal chassis rail 12, which is indicated here with dashed lines. A second horizontal plane 30 lies at the level of the tyre running surface 3 of the wheel 1. Towards the outside of the wheel, the horizontal planes 11, 13 are bounded by a vertical plane 14, which is arranged at the outer edge of the tyre running surface 3. Located transversely in relation to the vehicle longitudinal direction is the front wall 15, illustrated symbolically as a vertical plane. Located offset parallel in front of it is the wheel centre transverse plane 16. This plane is not outlined in Figures 1, 7 and 8.

In Figures 1, 7 and 8, in each case some components of the individual suspensions are illustrated as projections on the front walls 15 and the vertical planes 14.

All three independent suspensions are based in principle on a lower semileading arm often referred to as a semi-trailing arm 31, which is slightly changed from figure to figure. The pivot axis of the semi-trailing arm 31 extends between the articulation points D1 and D2, the rear articulation point D2 being located on the front wall 15, for example in the region of the longitudinal side sill, while the front articulation point D1 is a part of the longitudinal chassis rail 12 and, viewed in the direction of travel 10 is arranged behind the vertical wheel centre transverse plane 16. The semitrailing arm 31 ends in the rim space of the wheel 1 in an articulation point G, in which the lower joint of the wheel carrier 21 is mounted. This articulation point G, viewed in the direction of travel 10, lies in front of the vertical wheel centre transverse plane 16. Located in the region between the articulation points D1 and G is a zone 32 in which, for example, a coil spring of the vehicle springing or its saddle rests. Viewed in the direction of travel 10, a further articulation point D3 is fastened on the semitrailing arm 31 in front of this zone 32. Arranged in an articulated manner on this articulation point is a coupling rod 41, which supports the wheel carrier 21 at its articulation point E. The wheel carrier 21 and'the coupling rod 41 form a double crank which stands on the semi-trailing arm 31 and can pivot about the axis D3, G. The articulation point E1 on the wheel carrier 21 here lies behind the vertical wheel centre transverse plane 16, viewed in the direction of travel 10.

In Figure 1, the wheel carrier 21 is extended upwards via a wheel carrier arm 22. The upper end of the wheel carrier arm 22, which is led past the rim 5 and the tyre 2, forms the articulation point E1. The latter lies, together with the articulation points G and E, on the steering axis of the wheel 1 and is located behind the wheel centre transverse plane 16 and above the horizontal plane 13. Articulated in the articulation point E1 is a tension strut 51, which is supported in an articulation point C on the front wall 15. The tension strut 51, which forms the upper link of this independent suspension and supports the double crank formed by the wheel carrier 21 and the coupling rod 41, includes a right angle with the steering axis G, E1 in the exemplary embodiment. The articulation point C is located below the upper horizontal plane 13.

Figures 2 and 3 show in each case an independent suspension in front view, in which the wheel carrier 21 is arranged between the rim 5 and the brake disc 6. To this end, in Figure 2 the wheel carrier 21 is bent inwards over the brake disc 6, so that the articulation point E is located at least in the region of the rim flange there, or even outside the rim space. This construction makes a large kingpin inclination and a large, negative steering rolling radius possible.

In the case of Figure 3, the articulation point E is located in the rim space between the rim 5 and the brake disc 6. To this end, the coupling rod 41 is designed to be bent over in the region of the articulation point E. This variant permits a relatively small kingpin inclination with a likewise negative steering rolling radius.

Figures 4, 5 and 6 show an independent suspension, known from Figure 1, having a wheel carrier 21 partially enclosing the brake disc 6. The major part of the wheel carrier 21, and the articulation point E, is arranged outside the rim 5. In order to connect the lower articulation point G in the wheel space behind the brake disc 6 to the wheel carrier 21, the latter is forked underneath the stub axle 23. The forked sections 24, 25 of the wheel carrier 21 lead together once more in the wheel space behind the brake disc 6, in order to form the articulation point G there. This enclosure of the brake disc 6, which appears in Figure 6 as a ring approximately deformed to form an oval, is at the same time part of a track-rod arm 26 with its articulation point U.

This exemplary embodiment makes possible, inter alia, a brake disc 6 which is relatively large by comparison with the rim diameter.

In Figure 7, in contrast to Figure 1, the coupling rod 41 is extended upwards by the coupling rod arm 42. The coupling rod arm 42 is arranged underneath the articulation point E on the coupling rod 41 and follows at an appropriate distance the tyre sidewall 4 that is oriented towards the vehicle centre, and the running surface 3. It ends in the joint C1, which here is located on the line of intersection between the upper horizontal plane 13 and the vertical plane 14. The articulation points D3, E and C1 lie on a straight line. Hooked into the joint C1 is a tension rod 52, which supports the wheel carrier 21, together with the coupling rod 41 and its extension 42, on the front wall 15, underneath the upper horizontal plane 13, in an articulation point C2.

The straight line D3, C1 includes, for example, a right angle with the tension rod 52.

The tension rod 52 can be designed to be curved, as can the tension strut 51, in order to bend in the event of an accident-induced deformation of the vehicle front construction, instead of penetrating into the vehicle passenger compartment. It is of course also possible for the components 51 and 52 to be configured as lattice, corrugated or telescopic pipes or profiles, which slide into one another or compress instead of bending.

In the case of the independent suspension in Figure 8, the double crank formed from the wheel carrier 21 and the coupling rod 41 is supported with the aid of a spring strut 61. To this end, the spring strut 61 is mounted, for example using its damper tube 62, on the semi-trailing arm 31 in the region between the articulation points G and D3, at an articulation point D4. The articulation point D4, which here is placed in front of the pivot axis G, D3, viewed in the direction of travel 10, may also lie on or behind the pivot axis.

The other, upper end of the spring strut 61 is arranged in an articulated manner, for example in the wheel arch, which is not illustrated. The articulation point C4 there is located in Figure 8 in the upper horizontal plane 13 behind the wheel centre transverse plane 16, in relation to the direction of travel 10. Between the articulation points D4 and C4, the coupling rod 41 is supported on the damper tube 62 in an articulation point C3. Arranged there as a supporting element is, for example, a rubber bearing, a coupling element or the like.

In Figure 8, parts of the independent suspension are in each case projected onto the front wall 15 and the vertical plane 14.

Claims (5)

Claims

1. An independent suspension for front wheels of a motor vehicle, having a wheel carrier that can be pivoted for steering purposes, whose first and lower joint is mounted on a semi-trailing arm and whose second joint, lying above the horizontal wheel centre plane, is, on the one hand, connected to a coupling rod that is supported in an articulated manner on the semi-trailing arm and, on the other hand, is connected in an articulated manner to the vehicle superstructure via a tension rod, wherein the coupling rod extends upwards at least into the close proximity of the tyre running surface, ends there in a joint on the imaginary extension of the path between the articulation on the semi-trailing arm and the articulation on the wheel carrier and is supported on the vehicle front wall via the tension rod.

2. An independent suspension according to Claim 1, wherein the semi-trailing arm is articulated on a longitudinal chassis rail and the front wall.

3. An independent suspension according to Claim 1, wherein the tension rod is articulated on the front wall.

4. An independent suspension according to Claim 1, wherein the tension rod includes approximately a right angle with the centre line of the coupling rod and its extension.

5. An independent suspension for front wheels of a motor vehicle, substantially as described herein with reference to, and as illustrated in, the accompanying drawings.