- Swing axle
A swing axle is a simple type of
independent suspensionfirst used in early aircraft (1910 or before), such as the Sopwith and Fokker, usually with rubber bungee and no damping. Many later motor car rear swing axles have universal joints connecting the driveshafts to the differential, which is attached to the chassis. They do not have universal joints at the wheels: the wheels are always perpendicular to the driveshafts. Swing axle suspensions traditionally used leaf springs and shock absorbers. Volkswagens built before 1967 used torsion bars as their spring.
This type of suspension was considered better than the more typical
solid axlefor two reasons:
# It reduced
unsprung weightsince the differential is mounted to the chassis
# It eliminates sympathetic
camberchanges on opposite wheels
However, there are a number of shortcomings to this arrangement:
# A great amount of single-wheel camber change is experienced since the wheel is always perpendicular to the driveshaft
# "Jacking" on suspension unloading (or rebound) causes positive camber changes on both sides
# Reduction in cornering forces due to change in camber can lead to oversteer instability and in extreme cases
Mercedes-Benz addressed the inherent handling issues by producing swing axles with a single-pivot point located under the differential, and thus well below the axle. This configuration markedly reduced the tendency to "jack-up" and the later low pivot swing-axle equipped cars were praised in contemporary publications for their handling. The low-pivot swing-axle remained in production with
Mercedes-Benz W108280SE and 300SEL until 1972. It was fitted to the 300SEL 6.3, which was during the early 70s the worlds fastest production sedan. AMG modified 6.3 were also raced with the stock swing axle. [http://www.europeancarweb.com/features/epcp_0610_the_history_of_amg/index.html] http://www.youtube.com/watch?v=T-XjbQCR_l0
Swing axles were supplanted by
deDion axles in the late 1960s, though live axles remained the most common. Most rear suspensions have been replaced by more modern independent suspensions in recent years, and both swing and deDion types are virtually unused today.
The first production (1960–1964) Chevrolet
Corvairused this design. The alleged unsafe behaviour of the Corvairwas described in detail by Ralph Naderin his book " Unsafe at Any Speed". Second Production Corvairs (1965–1969) used a true independent rear suspension system.
Another use of the swing axle concept is Ford's "Twin I-Beam" front suspension for trucks. This has solid axles (so they do not transmit power). Though it is touted as an independent suspension system in that each tire rises and falls without affecting the position of the other, the parallelogram action of the A-arm suspension system is not present. Each tire in fact moves with a similar camber change to that of the powered swing axles for the rear wheels listed above. But the pivot point of the axles is located not in the middle of the car but nearly on the other beam of the chassis, so the effect is far less and quite safe.
* [http://www.autozine.org/technical_school/suspension/tech_suspension2.htm#Swing AutoZine Technical School site]
Wikimedia Foundation. 2010.
Look at other dictionaries:
swing axle — An independent rear suspension system in which each driving wheel can move up or down independently of the other. The differential unit is bolted to the frame and various forms of linkage are used upon which to mount the wheels. Drive axles,… … Dictionary of automotive terms
pivot swing axle — See low pivot swing axle … Dictionary of automotive terms
low pivot swing axle — A rear axle setup that attaches the differential housing to the frame via a pivot mount. A conventional type of housing and axle extend from the differential to one wheel. The other side of the differential is connected to the other driving wheel … Dictionary of automotive terms
axle — An axle is a shaft on which the wheels revolve. A full floating axle is used to drive the rear wheels. It does not hold them on nor support them. A semi floating or one quarter floating axle is used to drive the wheels, hold them on, and support… … Dictionary of automotive terms
swing arm suspension — An independent suspension system in which each axle pivots near the center of the vehicle and the movement of the axle changes the angle of camber. Also called swing axle … Dictionary of automotive terms
swing — See low pivot swing axle … Dictionary of automotive terms
Beam axle — Solid axle and Panhard rod on a 2002 Mazda MPV A beam axle is a suspension system, also called a solid axle, in which one set of wheels is connected laterally by a single beam or shaft. A live axle is a type of beam axle in which the shaft (or… … Wikipedia
Chevrolet Corvair — 1965 Chevrolet Corvair Corsa Hardtop Coupe Manufacturer Chevrolet Division of General Motors Production 1959–1969 … Wikipedia
Suspension (vehicle) — Suspension is the term given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. Suspension systems serve a dual purpose – contributing to the car s handling and braking for good active safety and driving … Wikipedia
Chapman strut — Lotus Twelve The Chapman strut is a design of independent rear suspension used for light cars, particularly sports and racing cars. It takes its name from, and is best known for its use by, Colin Chapman of Lotus. The characteristic feature of… … Wikipedia