Multi-link axle
The multi-link axle (also called multilink axle) is a type of independent wheel suspension on automobiles in which each of the two wheels of an axle is guided by four or five links . "The most complex form of independent wheel suspension is achieved with five rod core ..." The five links offer the greatest scope for design ("kinematic potential") for the targeted design of kinematics and elastokinematics.
A wealth of possible or actually implemented constructions is hidden behind the term. The overview is made more difficult by manufacturer-specific names.
Five-link axle
On the five-link axle, all links are simple rod links with two joints each. In the basic form, all links are connected between the body (usually with a separate subframe ) and the wheel carrier with two rubber bearings each acting as ball joints . Each of these five links deprives the wheel carrier of one of the six degrees of freedom, so that only compression and rebound remains possible ( degree of freedom f = 1).
The first five-link rear axle was initially tested by Mercedes-Benz in the Mercedes-Benz C111 and launched in 1982 under the name multi-link axle in the Mercedes-Benz W 201 . Compared to the semi-trailing arm axles predominantly used at that time, driving dynamics and ride comfort could be significantly improved. By varying the link geometry and the bearing stiffness, the five-link axle can be adapted to very different requirements.
In the case of steered wheels, the wheel carrier is connected via ball joints, which have a higher angular mobility than rubber bushings. The five-link axle as a front axle is limited in its design due to the wheel lock. At Audi -models and VW Passat B5 it was still realized, where it is referred to as "four-link suspension." The counting method does not include the tie rod in the handlebars.
Integral link axle
If the fifth link is designed as a coupling link between an upper and a lower link, the result is the integral link axle, which is used as a rear axle at BMW in the 5 and 7 series. The connection of the two links reduces the elastic pulling up of the axle when braking.
Four-link axle
(leading around spring)
The two upper links of a five-link suspension can be combined to form a triangular wishbone. The rear lower wishbone is usually adjustable in order to be able to set the correct toe -in. In the illustrated case, by the far overhead wishbone a very exact guidance of the fall ensured. This design can also be used as a front wheel suspension. The virtual spreading axis offers the prerequisite for the design of the scrub radius and joint radius even with limited installation space .
Trapezoidal link axle
In this design (factory designation), such as in the BMW E31 (1989–1999) or in the Audi Q5 8R (2008–2017), the lower link is trapezoidal and connected to the wheel carrier via an auxiliary link. The trapezoidal handlebar takes u. a. Torque around the wheel axle and reduces the twisting of the wheel carrier when braking. One rod guide is therefore sufficient on the upper level. The change in track when springing is controlled by a rear wishbone (rod link).
Sword handlebar axle
The wheel carrier is supported in the longitudinal direction on the car body by means of a flexible and torsionally soft arm (sword link) with a ball joint (rubber bearing) and is laterally guided by three rod links. This development with the factory designation sword link axle is used on the rear axle of the Ford Focus .
Shock absorber axis
The combination of a wheel-guiding damper strut with a broken lower wishbone is used as the front axle in BMW and Mercedes. The tie rod is the third link. The piston rod of the damper is a swivel arm. The two separate rods of the broken triangular link achieve a greater spread and a smaller scrub radius . The same principle is also available with a different handlebar arrangement than the rear axle, for example the Camuffo rear axle .
literature
- Wolfgang Matschinsky: Wheel guides for road vehicles. Kinematics, Elasto-Kinematics and Construction . 3. Edition. Springer, 2007, ISBN 978-3-540-64155-1 .
Web links
- Picture of the multi-link axle, but wrong explanation because the torsion bar is not a link
- Steel concepts for ultra-light axle construction (trapezoidal link axle) ( Memento from October 24, 2007 in the Internet Archive ) (PDF; 83 kB), also available on July 21, 2017.
Individual evidence
- ↑ Bernd Heißing, Metin Ersoy, Stefan Gies (eds.): Chassis manual . 3. Edition. Vieweg + Teubner, 2011, ISBN 978-3-8348-0821-9 , pp. 440–444 ( limited preview in Google Book search).
- ^ Wolfgang Matschinsky: Wheel guides of road vehicles. 2007, p. 17
- ^ Wolfgang Matschinsky: Wheel guides of road vehicles. , 2007, p. 34
- ^ Wolfgang Matschinsky: Wheel guides of road vehicles. 2007, pp. 412-413, further examples immediately afterwards
- ^ Wolfgang Matschinsky: Wheel guides of road vehicles. 2007, pp. 417-418
- ↑ Henning Wallentowitz, Konrad Reif (ed.): Handbook of automotive electronics : Fundamentals - components - systems . 2nd Edition. Vieweg + Teubner, 2011, ISBN 978-3-8348-0700-7 ( limited preview in the Google book search).