Multi-link suspension
| 5-link rear suspension |
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Rear view |
Top view |
Rear view
Top view
A multi-link suspension is a type of vehicle suspension design typically used in independent suspensions, using three or more lateral arms, and one or more longitudinal arms. A wider definition considers any independent suspensions having three control links or more multi-link suspensions. 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 the Mercedes-Benz C111 and later on their W201 and W124 series.
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 a trailing arm or wishbone, which has two bushings at one end.
On a front suspension one of the lateral arms is replaced by the tie-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.
For a solid axle vehicle the multi link suspension provides control of the axle during suspension cycling and to locate the axle under the vehicle. The most common is the four link with panhard bar. This is found in many cars and pickup trucks. The four link is also used heavily in off-road racing and drag racing. The four link for a solid axle has a few variations such as the triangulated four link and double triangulated four link. Although common in off-road vehicles these are not commonly found on the street.
The arms have to control toe/steer and lateral compliance. This needs a pair of arms longitudinally separated.
Multilink suspension is costly and complex. It is also difficult to tune the geometry without a full 3D computer aided design analysis. Compliance under load can have an important effect and must be checked using a multibody simulation software.
5-link rear wheel suspension mechanism (front view)
5-link rear wheel suspension mechanism (top view)
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