Amulti-link suspension is a type of independentvehicle suspension having three or morecontrol links per wheel.[1] These arms do not have to be of equal length, and may be angled away from their "obvious" direction. It was first introduced in the late 1960s on theMercedes-Benz C111[2] and later on theirW201 andW124 series.[3][4]
Typically each arm has a spherical joint (ball joint) or rubber bushing at each end. Consequently, they react to loads along their own length, in tension and compression, but not in bending. Some multi-links do use atrailing arm,control arm orwishbone, which has two bushings at one end.
On a front suspension one of the lateral arms is replaced by thetie-rod, which connects the rack or steering box to the wheel hub.
In order to simplify understanding, it is usual to consider the function of the arms in each of three orthogonal planes:
The arms have to controltoe/steer and lateral compliance. This needs a pair of arms longitudinally separated.
The arms have to controlcamber, particularly the way that the camber changes as the wheel moves up (into jounce, or bump) and down into rebound or droop.
The arms have to transmit traction and braking loads, usually accomplished via a longitudinal link. They also have to controlcaster. Note that brake torques also have to be reacted - either by a second longitudinal link, or by rotating the hub, which forces the lateral arms out of plane, so allowing them to react 'spin' forces, or by rigidly fixing the longitudinal link to the hub.
Multi-link suspension allows the auto designer the ability to incorporate both goodride and goodhandling in the same vehicle.
In its simplest form, the multi-link suspension is orthogonal—i.e., it is possible to alter one parameter in the suspension at a time without affecting anything else. This is in direct contrast to adouble wishbone suspension, where moving a hardpoint or changing a bushing compliance will affect two or more parameters.
The benefit of the triangulated and double-triangulated arrangement is that they do not need aPanhard rod. The benefits of this are increased articulation and potential ease of installation.
Multilink suspension is costly and complex. It is also difficult to tune the geometry without a full 3Dcomputer aided design analysis. Compliance under load can have an important effect and must be checked using amultibody simulation software.
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