Variomatic - encyclopedia article about Variomatic.

Transmission types
Manual Sequential manual Automatic Tiptronic Semi-automatic Twin-clutch gearbox Saxomat Non-synchronous
Continuously-variable Variomatic Multitronic
Bicycle gearing Derailleur gears Hub gears
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Variomatic

Variomatic is the stepless, fully automatic transmission of the Dutch car manufacturer DAF, using a drive belt and two pulleys. It was the first continuously variable transmission (CVT) (as opposed to shifting between separate gears). In theory, this always produces the optimum torque. The variomatic was introduced by DAF in 1958, also putting an automatic gear box in the Netherlands for the first time. The variomatic was introduced on the DAF 600. Because the system does not have separate gears, but one (continuously shifting) gear and a separate 'reverse mode' (as opposed to a reverse gear), the gear works in reverse as well, giving it the interesting side-effect that one can drive backwards as fast as forwards. As a result, in the former Dutch annual backward driving world championship, the DAFs had to be put in a separate competition because no other car could keep up. Thus, these very cheap and simple cars were the 'formula one' in this competition.

Manual transmission remained dominant in Europe. When DAF was taken over by Volvo, the Variomatic patents were transferred to a company called VDT (Van Doorne Transmissie), later taken over by Bosch. Audi reintroduced an improved version of the variomatic in the early 21st century under the name Multitronic. This system uses a metal belt and lacks a limit to the number of gears available, switching between them without noticeable shocks. These metal drive belts are the most important part of CVT. The only factory still producing these belts, the Bosch factory in the Netherlands, produced the ten millionth belt on 9 May 2007. It is used in over 40 car models, these days even including expensive brands like Mercedes.

The final drive has two pulleys with moveable conical drums. The distance between the drums is controlled by the engine vacuum in the inlet manifold and engine RPM, through centrifugal weights inside the drums. Between the two pulleys runs a drive belt. As a result of change in the distance of the conical drums in both pulleys, the diameters and so also the reduction ratio changes continuously.

With the DAF 600 - 55 each rear wheel was propelled individually by a pair of conical drums and drive belt with the effect of a limited slip differential: if a drive wheel on slippery road revs up, the other wheel can still transfer the full torque. This results in unusually good traction characteristics, which were also a reason for successes of the DAFs in rallies. It was even used in a Formula 1 car, but it was only allowed to start in one race before it was banned since it gave an unfair advantage. There were several disadvantages that accompanied the lack of a true differential gear. Although each belt could settle (independent of the other) into it's optimum position, thus allowing for wheel speed variation, the system was slow to operate and depended on the pulleys being turned. This led to rapid tire wear and placed stress on other transmission components. Snapped drive shafts were common. Low speed handling in icy conditions was interesting as the system tended to drive the car forward against the influence of the steered wheels. Later cars, the 46, 66 and Volvo variants were fitted with a differentially geared axle.

The Variomatic is also used in today's motorscooters. It is a standard part of all common scooters since 1985, and several companies such as Malossi, Polini, Doppler and Stage6 are offering tuning clutches and variomatic for most common 50, 70 and 125 cc scooters.

A version of the Variomatic called Transmatic is still made by DAF's Van Doorne's Transmissie b.v. in Tilburg, The Netherlands and Nissan Primera is offered with this transmission.

Today the Continuously Variable Transmission (CVT) works according to the same principle. Rather than rubber drive belts, the modern transmission is made much more durable by the use of steel link belts. The CVT is available in cars such as Audi, Honda and the MINI ONE and MINI Cooper.

range of input/output ratios in addition to its infinite number of possible ratios; this qualification for the IVT implies that its range of ratios includes a zero output/input ratio that can be continuously approached from a defined 'higher' ratio.
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A sequential manual transmission (or sequential manual gearbox) is a type of manual transmission used on motorbikes and high-performance cars or auto racing, where gears are selected in order and random access to specific gears is not possible.
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automatic transmission (commonly abbreviated as "AT") is an automobile gearbox that can change gear ratios automatically as the vehicle moves, thus freeing the driver from having to shift gears manually (similar but larger devices are also used for railroad locomotives).
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Tiptronic is a type of discrete automatic transmission developed by Porsche and used in its vehicles and those of its licensees. A Tiptronic transmission can operate just as the common type of automatic transmission, but it also allows the driver to override the automatic mode by
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A semi-automatic transmission (also known as clutchless manual transmission, dual-clutch transmission, automated manual transmission, e-gear, or paddle shift gearbox
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A twin-clutch gearbox or dual clutch transmission (DCT) is a semi-automatic transmission with separate clutches for odd and even gears. The outer clutch drives the odd numbered gears and reverse, while the inner clutch drives the even numbered gears.
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Saxomat was a type of automatic clutch available as an option on Fiat 1800, Saab 93, Volkswagen Beetle, Borgward, Goliath, DKW, BMW, Opel, NSU, Glas, Trabant and Wartburg. Opel sold it as Olymat; Trabant and Wartburg named the system Hycomat.
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A non-synchronous transmission is a form of transmission based on gears that do not use synchronizing mechanisms. They are found commonly in various types of agricultural, commercial, and military vehicles.
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The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of
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In 2000 Audi launched a new stepless transmission called Multitronic. Based on the principles of continuously variable transmission (CVT) popularised by DAF, multitronic offers a stepless automatic transmission in which the ratio between the input shaft and output shaft can be
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gearing on a bicycle is the selection of appropriate gear ratios for optimum efficiency or comfort. Different gears and ranges of gears are appropriate for different people and styles of cycling. Multi-speed bicycles allow gear selection to suit the circumstances, e.g.
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Derailleur gears are a variable ratio transmission system commonly used on bicycles, consisting of a chain, multiple sprockets and a mechanism to move the chain from one sprocket to another.
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Hub gears or internal-gear hubs are a type of gear system used on bicycles. Hub gears are used mostly on utility bikes and various types of small wheeled bicycle, such as folding bikes.
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Motto
"Je maintiendrai" (French)
"Ik zal handhaven" (Dutch)
"I shall stand fast"¹
Anthem
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DAF Trucks NV

Subsidiary of PACCAR since 1996
Founded 1993
Headquarters Eindhoven, Netherlands

Key people Aad Goudriaan, President
Industry Manufacturing
Products Trucks
Website www.daf.
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pulley (also called a sheave or block) is a wheel with a groove between two flanges around its circumference. The groove normally locates a rope, cable or belt. Pulleys are used to change the direction of an applied force, transmit rotational motion, or realize a mechanical
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torque (or often called a moment) can informally be thought of as "rotational force" or "angular force" which causes a change in rotational motion. This force is defined by linear force multiplied by a radius.

The SI unit for torque is the newton meter (N m). In U.S.
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DAF 600 is a small family car that was DAF's first production passenger car, and manufactured from 1959 until 1963. The 600 was the first car to have a continuously variable transmission (CVT) system - the innovotive DAF Variomatic.
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Audi AG

Public (Xetra: NSU )
Founded 1910
Founder August Horch
Headquarters Ingolstadt, Germany

Key people Rupert Stadler, chairman
Industry Automotive
Products Luxury Automobiles, Engines
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Bosch is a popular surname in Catalan and Dutch; it means forest. If you searched for Bosch you may be looking for:

Companies

Robert Bosch GmbH – the company who trade as Bosch

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For other uses of the name Mercedes, see Mercedes.

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manifold is an abstract mathematical space in which every point has a neighborhood which resembles Euclidean space, but in which the global structure may be more complicated. In discussing manifolds, the idea of dimension is important.
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