Talk:Variomatic

Illustration needed
This passage begs for an illustration:
 * 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.
 * --Nil0lab 17:40, 3 April 2006 (UTC)
 * Better?

No that is not a DAF transmission that is a "Positive Infinitely Variable" transmission by PIV drives GMBH. Near but not right.

F1
As far as I know, this car was never allowed on the track. It is now residing at the Van Doorne Transmissie (VDT) factory.


 * Nope, David Coulthard tested it in 1993, but allegedly Bernie had it banned because he didn't like the noise it made. Mr Larrington (talk) 14:52, 14 February 2013 (UTC)

Invention and Hub van Doorne
Can anyone explain the chronology of the twin-conical pulley variable speed transmission, and van Doorne's involvement in it? It appears clear that van Doorne didn't invent the mechanical design of the drive, nor even its first use as a car transmission. He may well have originated control of the pulleys by vacuum diaphrams, and the use of two separate final belt drives, rather than a single. Does anyone know the inventor, or even date, of the first basic variable drive of this form? Andy Dingley (talk) 21:47, 12 July 2010 (UTC)

How does reverse work
How does reverse work on these ? It is all very well to say they go just as fast in reverse,  thats great, but it doesn't explain how the reverse happens.Eregli bob (talk) 05:09, 5 August 2012 (UTC)


 * Hard to explain without a diagram. It's the fairly common arrangement of two bevel gears, one of which is engaged selectively for each direction. In the DAF, the drive from the engine shaft to the first drums is through such a bevel gearbox - this turns the rotation direction by 90&deg; and also acts as the reduction that's normally provided by the final drive in a conventional rear axle. The input shaft has two bevels which can slide in and out of engagement with the bevels on the drum shafts, controlled by the gearstick with Forward/Neutral/Reverse positions. Andy Dingley (talk) 12:11, 5 August 2012 (UTC)