Independent suspension
The independent suspension is a type of wheel control in which the two opposite wheels of multi-lane road vehicles can deflect independently of one another. It is a mechanism with a degree of freedom f = 1.
The independence of the wheel positions and the low unsprung mass are advantages compared to joint wheel guidance using a rigid axle .
development
The oldest known application of an independent suspension is that on the front axle of the l'Obéissante, a steam bus from Amédée Bollée (1873). In 1897 Joseph Guédon and Gustave Cornilleau built a Voiturette with individually suspended front wheels. The automobiles built by Decauville from 1898 onwards also had independent wheel suspension, which worked as follows: A vertical pin was attached to the steering knuckle , which could rotate and move up and down in a socket attached to the chassis and was supported on a transverse leaf spring. This design was also used by Sizaire-Naudin from 1906. With Morgan (from 1909) the pin was fixed and a (coil-sprung) sleeve moved with the steering knuckle. From 1922 there was a similar design from Lancia in the Lambda . In 1920 Karl Slevogt developed a front "swing axle", similar to the Decauville, with a movable pivot, but with a leaf spring at the bottom, which was installed in all Apollo automobiles from 1921 onwards . Edmund Rumpler's Teardrop Car with pendulum axles (swing axles) was created in 1921. From the 1930s, the front suspension on double wishbones prevailed (sometimes a transverse leaf spring took over the function of one of the two links on each front wheel). The suspension on longitudinal swing arms is also known from this time. ( André Dubonnet ) The wheel-guiding suspension strut invented by Earle S. MacPherson was available from 1950 and is today the most frequently used independent wheel suspension on the front axle. In 1982 the "multi-link axle" with five links came up, which is used in different designs and under different names ("multi-link axle", "five-link axle" or "four-link axle" with two combined links).
Types on the front axle
Suspension on struts:
- The suspension strut axle with MacPherson struts is the most commonly used design in passenger cars today and combines suspension ( coil spring ), damping and wheel guidance in one component. A lower wishbone guides the wheel together with the suspension strut, which is firmly connected to the steering knuckle (wheel carrier).
Suspensions with handlebars are:
- Double wishbone suspension with transverse wishbones . The upper link is usually shorter than the lower one so that the track width does not change too much during compression. They can be combined with coil, leaf or torsion bar springs. It is used in upscale vehicle classes and in sports and commercial vehicles.
- In the case of the crank arm axle, the links are arranged lengthways, and the wheelbase changes during compression. It was invented by Ferdinand Porsche and used almost exclusively in his constructions (for example the Auto Union racing car and the VW Beetle ). Torsion bar springs are typical here.
- There were seldom triangular links at the bottom and lengthways (or slightly adjusted) at the top.
- Multi-link axle as a collective name for a large number of different structural designs, such as the four-link axle with a separate lower wishbone.
Suspensions where the steering knuckle is directly hinged to the chassis:
- front swing axle used to be found on small cars, otherwise only on all-wheel drive construction site and off-road vehicles.
- With the swing arm , the wheel sits on a longitudinally arranged carrier that rotates upwards as a whole for compression - for steering either the swing arm with bearing, spring and shock absorber is pivoted around an approximately vertical axis ( Dubonnet spring knee ) or it carries on it Tip the wheel, which is swiveling on the steering knuckle. Then the caster changes significantly during compression.
Types on the rear axle
Various designs were or are in use:
Suspensions where the steering knuckle is directly hinged to the chassis:
- Swing axle . In this case, the semi-axles, which are attached in a pendulous manner, spring up and down in the vertical transverse plane of the vehicle. With driven axles, they are connected to the differential gear via cross or constant velocity joints , which is rigidly attached to the vehicle body (e.g. VW Beetle ). The disadvantage of the pendulum axle is a large change in camber and a high moment center .
- Trailing arm axle , trailing arm axle , ahead of Mercedes diagonal swing axle respectively.
- Spherical double wishbone axle: The steering knuckle is supported on the car body by means of a boom with a ball joint (rubber bearing) and is laterally guided by two wishbones. At BMW, this type of axle is called the central link axle.
The suspension on handlebars:
- Double wishbone axle , also with wheel-guiding transverse leaf springs, was used in particular in racing, also as a track-correcting "Weissach axle" in the Porsche 928 .
- Sword arm axle: The steering knuckle is supported by a flexible arm with a ball joint (rubber bearing) on the car body and is laterally guided by three wishbones.
- Multi-link axle : Collective term for a large number of different designs with three to five links. An example is the multi-link axle with five links. With it, articulation points, handlebar lengths and joint stiffnesses can be designed comfortably flexible in the longitudinal and transverse directions without undesired toe-in and camber changes.
Suspension on MacPherson struts or shock absorber struts and wishbones: Camuffo rear axle , Chapman axle and other designs.
literature
- Robert Bosch GmbH: Automotive paperback. Friedr. Vieweg & Sohn, Wiesbaden, 26th edition 2007, ISBN 978-3-8348-0138-8 .
- Reimpell, Jörnsen; Betzler, Jürgen: Chassis Technology: Basics , Würzburg 2005; ISBN 3-8343-3031-0
Individual evidence
- ↑ Bernd Heißing, Metin Ersoy, Stefan Gies: chassis manual . , P. 437 ff.
- ↑ Technical knowledge of automotive engineering, European teaching aids, 27th edition 2001, ISBN 3-8085-2067-1 , page 469
- ↑ Archive link ( Memento of the original from January 22nd, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Front axle
- ↑ http://morgan3w.de/technic/technic_de.htm front axle
- ↑ image of the axis
- ↑ http://images.vogel.de/vogelonline/bdb/494800/494840/sourceimage.jpg Picture of a central link axle
- ↑ Henning Wallentowitz, Konrad Reif (Ed.): Handbook of Motor Vehicle Electronics : Basics - Components - Systems , Vieweg and Teubner / Springer-Verlag Wiesbaden, p. 179
- ↑ oldtimer-markt.de (accessed on February 16, 2011)
- ↑ http://www.alfisti.net/alfa-forum/attachments/alfisti-talk/9371d1265449908-alfa-romeo-giulietta-ii-focus.jpg Pictures of sword handlebar axles (VW and Ford)
