Rear swing arm (motorcycle)

from Wikipedia, the free encyclopedia
Rear swing arm NSU Supermax

The rear swing arm is a movably mounted rear wheel suspension of a motorcycle with suspension in the form of a drawn long arm swing arm , the pivot point of which is in front of the wheel in the direction of travel.

Until the mid-1930s, rigid-frame motorcycles without a rear swing arm were the norm. In the 1950s, the design of the rear swing arm prevailed on almost all motorcycles compared to the straight-line suspension introduced at the end of the 1930s .

history

The first motorcycles had rigid diamond frames without a movable rear swing arm. Unsprung rear wheels were still common on motorcycles until the 1930s. The first examples of motorcycles with rear swing arms in cantilever design, however, are already known from the Austro-Hungarian manufacturer Rösler & Jauernig from 1903. The first series manufacturer of a rear swing arm was NSU Motorenwerke , which in 1911 designed the rear part of the frame of the NSU 2 1/2 model as a swing arm with a central spring under the saddle. In 1913 Indian offered a leaf-sprung rear swing arm upon request, and in 1922 DKW launched the Lomos chair wheel with a spring-loaded rear swing arm . The spring was encapsulated in a telescopic tube. Moto Guzzi with the GT (1928), HRD-Vincent (1931) and Gilera (1937) pioneered the reintroduction of the rear swing arm on motorcycles, after the rear swing arm had been abandoned due to the lack of directional stability due to the increasing engine power. First of all, straight-ahead suspension became widespread in the 1930s, but was briefly established in the post-war period, but was then replaced by the rear swing arm.

While the front wheels of motorcycles only rarely to swing be hung - currently at the Springer fork of Harley-Davidson , as well as motorcycle sidecars  - the construction has the swingarm enforced for all motorcycles.

  • NSU (1911) with rear swing arm with central spring

  • Indian (1913) rear swing arm with leaf spring

  • Lomos chair wheel (1923) with a coil-sprung rear swing arm

  • Moto Guzzi GT (1928) rear swing arm with coil springs and friction damper

Types

Double swing arm

The drawn two-arm swing arm is the simplest solution from a technical point of view. Two-arm swing arms can be built very easily from round or oval tubing. They require the removal of the rear wheel to the rear (for this purpose, motorcycles used to have hinged rear fenders) or to the bottom using a work stand. They combine high stability with low mass, which keeps the unsprung masses low. With increasing engine power of road machines at the beginning of the 1970s, the often tightly dimensioned swing arms were replaced by swing arms made of rectangular tube, which offer greater stability.

The swing arm cushions helical compression springs, which are arranged between the swing arms and the rear frame parts - or a special frame arm. Leaf springs, helical tension springs, torsion bars and rubber elements have rarely been used as resilient elements. Depending on the construction, one to four compression springs are common, the arrangement of which does not have to be symmetrical. At first there were no vibration dampers, later adjustable friction dampers were introduced, which were attached between the swing arm and frame (compare Moto Guzzi). They were replaced by the hydraulic dampers. In the last development step, the spring (s) and damper are combined into one assembly: the spring-damper units , often called struts . From the mid-1950s, the drawn swing arm with two spring struts became common. The first German motorcycle to be built in series with this arrangement was a 1953 UT .

Cantilever swingarm and monocross

The term "cantilever swing arm" originated from the designation of the rear wheel swing arm for various models by HRD-Vincent , which was constructed in 1931 as a "triangular structure". Similar systems were used in Germany by NSU at NSU Fox and Riedel for Imme R 100 in 1949, but without using the term “cantilever”.

In 1973, Yamaha developed the monocross suspension, a rear swing arm with a single spring system, which was used by world champion Håkan Andersson for the Motocross World Championship ; the Monocross word mark is protected by Yamaha. In 1974 the system was used in the Yamaha OW26 racing motorcycle , now known as the cantilever suspension.

With the cantilever suspension, the longer lever arm carries the wheel, the shorter arm is supported against the frame by an inclined or approximately horizontal spring (usually with a vibration damper); the feather is often under the saddle. For the cantilever suspension with rocker arm and vertical strut different names have been used by different manufacturers over the years, including: a. Pro-Link (Honda), Uni Trak (Kawasaki), Full Floater (Suzuki).

  • Cantilever suspension with triangular structure of the rear wheel swing arm ( HRD-Vincent )

  • Pro-Link (Honda)

  • Rear swing arm with bell crank

Single-sided swing arm

Single-sided swing arms, which only guide the wheel on one side, have been used in automobiles and rarely in motorcycles (for example Imme R 100) since the 1930s . In 1980, BMW began equipping its motorcycle models with single-sided swing arms with the BMW R 80 G / S , which BMW called Monolever . The principle has been continuously developed up to the current Paralever swing arm with torque support. Nowadays, besides BMW, other motorcycle manufacturers also use single-sided swing arms, for example Ducati , Honda , Moto Guzzi , MV Agusta , Triumph and various small series manufacturers. As a rule, they are heavier or less stiff than two-armed swing arms for the same weight, but allow easy and quick wheel changes. They are therefore often used on motorcycles in long-distance races .

Drive train swing arm

Drive unit swing arms carry the motor , the gearbox and the wheel drive in a housing . With directly on the guided from the transmission shaft mounted wheel, they are often at scooters used. There, the poorer suspension due to the inertia of the larger unsprung mass is accepted in favor of the cost-effective and maintenance-free power transmission; the chain tension remains constant without the need for special tensioning devices. A widespread motor scooter with a drive unit swing arm was the Vespa , which was built from 1946 . Motorcycles with Unit swing were the Imme R 100 and also of Norbert Riedel designed Victoria Swing.

Combination with cardan drive

With cardan drive of the rear wheel, the cardan shaft can run in a tube arm of the rear wheel swing arm .

literature

  • Christian Bartsch (ed.): A century of motorcycle technology. VDI-Verlag, Düsseldorf 1987; ISBN 3-18-400757-X .
  • Tony Foale, Vic Willoughby: Motorcycle Chassis Today. 1st edition. Motorbuch Verlag Stuttgart 1988, ISBN 3-613-01226-X .
  • Stefan Knittel: Motorcycle Lexicon. BLV Verlag, Munich 1981, ISBN 3-405-12226-0 .
  • Peter Witt: Motorcycles. 1st edition. Verlag Technik, Berlin 1989, ISBN 3-341-00657-5 .

Web links

Commons : Motorcycle Swing  - Collection of images, videos, and audio files

Individual evidence

  1. ^ Paul Simsa: Development of the motorcycle chassis. In: MOTORCYCLE. 1/78.
  2. ^ Peter Schneider: NSU im Bild - Motorräder since 1900. 1st edition, Motorbuch Verlag, Stuttgart 2000, ISBN 3-613-02063-7 , pp. 28 and 199.
  3. ↑ Jerry Hatfield: Indian. Schrader Verlag 1994 (English Indian Motorcycle Buyer's Guide, 1989), ISBN 3-921796-17-2 , p. 21.
  4. ↑ Gilera 250 (accessed December 22, 2015)
  5. ^ Stefan Knittel: Motorcycle Lexicon. P. 69.
  6. ^ Stefan Knittel: Motorcycle Lexicon. P. 68.
  7. ↑ Norbert Adolph In: Christian Bartsch (Ed.): A century of motorcycle technology. Pp. 182, 192.
  8. ↑ Norbert Adolph In: Christian Bartsch (Ed.): A century of motorcycle technology. P. 195.
  9. ^ Roy Bacon: British Motorcycles of the 1930s. Osprey Publishing, 1995., ISBN 1-85648-204-9 , p. 193.
  10. ↑ Norbert Adolph In: Christian Bartsch (Ed.): A century of motorcycle technology. P. 192.
  11. ↑ register.dpma.de Register number: 940925 (accessed on December 17, 2015)
  12. ↑ yamaha-motor.eu Yamaha Technologie 1973: First monocross suspension (accessed on December 17, 2015)
  13. ^ Peter Witt: Motorcycles. P. 36.