The invention relates to a vehicle suspension, in particular a trailed-arm suspension, and it relates more particularly to an improvement to a spring for such a suspension, enabling the compression of the spring to be controlled better.
The invention applies to any suspension in which a spring is installed to bear between two supports at a variable spacing and in which at least one of the supports is constrained to move along a curved trajectory relative to the other. This applies in particular to a so-called “trailed-arm” suspension. For example, one of the supports can be secured to the chassis and the other can be defined by an arm hinged to said chassis.
When the open angles are large (i.e. when the stroke of the suspension is large), retaining the spring leads to technical problems that are not negligible. In particular, a coil spring mounted between two supports of this kind becomes naturally curved between the two bearing points, and contact between the end turns of the spring and said supports ceases to be satisfactory, sometimes taking place via a single point when the suspension is in the relaxed position (i.e. while the wheel is hanging down), and that can lead to the spring disengaging, or at least to noise and to points where corrosion starts. In addition, the stacking of the turns on compression is irregular.
The invention relates to an improvement serving both to improve docking of the spring with its supports, and also to ensure that the turns stack regularly when the spring is compressed.
More particularly, the invention provides a vehicle suspension including a subassembly constituted by a coil spring mounted to bear between two supports of variable spacing, the suspension being characterized in that at least one support is constrained to move along a trajectory that is curved relative to the other, and in that the variation in the pitch of an end portion of the corresponding end turn bearing against said support is negative or zero.
Advantageously, said end turn is off-center relative to a general axis of said spring. These two characteristics are very advantageous in combination.
The shape of this end turn provides contact that is more complete (i.e. that extends over a longer length of the turn) between the end turn and the corresponding support, in particular under a light load.
The invention can be better understood and other advantages thereof appear more clearly in the light of the following description given purely by way of example and made with reference to the accompanying drawing, in which:
With reference to
The spring 12a constituting the improvement of the invention is shown in its non-stressed state in
Because of these characteristics, the spring 12a is mounted in much more satisfactory manner between the two supports, as can be seen in
Number | Date | Country | Kind |
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0311814 | Oct 2003 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FR04/02564 | 10/11/2004 | WO | 4/10/2006 |