Variable speed transmission (mechanical)

A variable speed transmission is a mechanical device making it possible to vary continuously the report/ratio of Démultiplication of an engine. It is used to replace the Gear box.

Technology

The variable speed transmission is composed of two Poulie S whose throats are with variable spacing, connected by a belt. According to the spacing of the walls of the pulleys, the belt penetrates more or less close to the center, and changes the ratio of reduction gearing consequently.

Generally, the report/ratio is chosen by a centrifugal device, according to the number of revolutions of the engine: the more quickly the engine turns, the more reduction increases, which tends to make slow down the engine.

Use

the Auto-cycle S, whose celebrates it Mobylette
Some automatic cars equipped with a transmission with continuous variation: (Daf, Ford Fiesta, Ford Focus, FIAT Punto, all the AUDI Multitronic version, Honda Jazz, Toyota Prius, etc)

Advantage-disadvantages

Rendement mechanical slightly lower than a box at speeds
Possibilité of preselections for a use in sequential mode manual (6, 7 speeds)
There is an infinity of ratios of reduction gearing in automatic mode, which allows the adaptation instantaneous and continuous between the load and the minimum speed of rotation of the engine (acoustic comfort and less consumption which compensates for the loss of mechanical output)
the driver does not have to be concerned with anything.

External bonds

SeCVT Suzuki Electronically-controlled (French & English FlashMedia interactive), to test press on the keys: Power D&M or Up-Down
an explanatory page very complete and well done with diagrams

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