Editing Multi-link suspension

{{Short description|A type of vehicle suspension}}
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A '''multi-link suspension''' is a type of independent [[suspension (vehicle)|vehicle suspension]] having three or more [[suspension link|control links]] per wheel.<ref>{{cite web | url=https://help.altair.com/hwdesktop/hwx/topics/motionview/rear_multi_link_r.htm | title=Rear Multi-link }}</ref> 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]]<ref>Bastow, D. (1970) Suspension ad Steering, Automobile Engineer, 8 May 1970, 217–231.</ref> and later on their [[Mercedes-Benz W201|W201]] and [[Mercedes-Benz W124|W124]] series.<ref>von der Ohe, M. (1984) Independent Wheel Suspension, US Pat. 4,444,415, Filed Dec. 23, 1981</ref><ref>von der Ohe, M. (1983) Front and Rear Suspension of the New Model W201, SAE technical Paper 831045.</ref>

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]],  [[control arm]] or [[Double wishbone suspension|wishbone]], which has two bushings at one end.

On a front suspension one of the lateral arms is replaced by the [[Tie rod|tie-rod]], which connects the rack or steering box to the wheel hub.


==Layout==
In order to simplify understanding, it is usual to consider the function of the arms in each of three orthogonal planes:

*Top view:
The arms have to control [[Toe (automotive)|toe]]/steer and lateral compliance. This needs a pair of arms longitudinally separated.

*Front view:
The arms have to control [[Camber angle|camber]], particularly the way that the camber changes as the wheel moves up (into jounce, or bump) and down into rebound or droop.

*Side view:
The arms have to transmit traction and braking loads, usually accomplished via a longitudinal link. They also have to control [[caster angle|caster]]. 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.


==Advantages==
Multi-link suspension allows the auto designer the ability to incorporate both good [[ride quality|ride]] and good [[car handling|handling]] 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 a [[double 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 a [[Panhard rod]]. The benefits of this are increased articulation and potential ease of installation.

==Disadvantages==
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.

==Gallery==
Source:<ref>{{cite book|last=Simionescu|first=P.A.|title=Computer Aided Graphing and Simulation Tools for AutoCAD Users|year=2014|publisher=CRC Press|location=Boca Raton, Florida|isbn=978-1-4822-5290-3|edition=1st}}</ref>
<gallery>
File:5link-rear1-small.gif| 5-link rear wheel suspension mechanism (front view)
File:5link-rear2-small.gif| 5-link rear wheel suspension mechanism (top view)
File:5link-steer front view.gif| 5-link suspension mechanism with rack-and-pinion steering input (front view)
File:5link-steer top view.gif| 5-link suspension mechanism with rack-and-pinion steering input (top view)
</gallery>

==See also==
* [[Automotive suspension design]]

==References==
{{Reflist}}
*Adams, H. (1993). ''Chassis Engineering''. New York, New York, Penguin Putnam.
*Milliken, W.F., Milliken, D. (2002). ''Chassis Design: Principles and Dynamics'', SAE International.

==External links==

* [https://web.archive.org/web/20071001030645/http://syd.mech.eng.osaka-u.ac.jp/papers/1998/09_AIAA_ga.pdf 1998 technical paper on the design of multilink suspensions]
* [https://dx.doi.org/10.1016/S0094-114X(02)00037-X 2002 technical paper on the design and analysis of five-link suspensions]

{{Automotive handling}}
{{Powertrain}}
{{Chassis control systems}}
{{Use dmy dates|date=March 2018}}

[[Category:Automotive suspension technologies]]