DAF Daffodil - Running Gear

Running Gear

The DAF 600 was the first car to have a continuously variable transmission (CVT) system - the innovative DAF Variomatic., the same system was carried over to the 750 and its variants. The DAF Variomatic employs centrifugal weights to control the drive ratio of the transmission and is enhanced by the engine manifold vacuum. The action of the bob weights and inlet vacuum combined to pull together the cheeks of two, variable diameter, driving pulleys, driven directly from the engine. These were connected, by rubber 'V' belts, to two similar driven pulleys, connected to the drive wheels. The cheeks of the driven pulleys were held together by spring tension, which was progressively overcome as the drive pulleys expanded and the tension of the belts increased. The DAF Variomatics were thereby the only cars ever produced which went faster by the simple expedient of gently and gradually releasing the accelerator once top engine speed had been reached, as the increased vacuum took over from the reducing bob weight speed. The Variomatic also permitted increased engine braking by operating a switch on the dashboard which reversed the action of the vacuum on the pulley's diaphragm, seeking a lower ratio with increased manifold vacuum. Two separate transmissions ran the two driving wheels, eliminating the need for a differential. The two transmissions could provide different drive ratios, permitting the wheels to rotate at different speeds. The duplication also provided redundancy. If one belt broke, the vehicle could still be driven. An interesting feature: putting the car in reverse reversed the entire drive system. This enabled the vehicle, at least the earlier examples, in theory to reach the same top speed in reverse as forward.