The Variomatic should offer a relatively low cost alternative to the automatic gearbox for smallervehicles and/or engines with low torque. In the DAF. 20 Dec In the Variomatic Drive transmission, the driveshaft drives a transverse countershaft (1) with two vee pulleys (2) attached to it. The power is then. Buy low price, high quality variomatic transmission with worldwide shipping on

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There were several disadvantages that accompanied the lack of a true differential gear. First of all, the torque comes in from below center into the transfer case. He was never to be seen again. Although it remained in production until the Variomatic suffered from several drawbacks, in particular it had limited torque capacity and tranmission occupied a large installation volume.

Achieving the best possible fuel consumption, however, would have required that the transmission be able to match the engine’s actual condition with a range of fuel consumption values over a range of speeds and throttle openings.

January 5, at This affects a multiple sliding-sleeve in the engine compartment, and cancels out the affect of the vacuum. Before the advantage of electronics, one simple but effective design was the DAF-designed Variomatic transmission, designed and developed by Hubb Van Doorne, which was also used in the smaller Volvo models, the 66 and Retrieved from ” https: The system incorporated a pair of V-section rubber belts ran under tension between primary and secondary pulleys having variable groove widths.

This button is pulled when braking is anticipated, e. When the driving mode is selected, hydraulic pressure from an engine-driven pump acts on the appropriate clutch actuator. Manumatic Semi-automatic Electrohydraulic Dual-clutch. In theory, this always produces the optimum torque.

How it Works: The Variomatic Transmission

Changes in the gear ratio were obtained by varying the operative diameter of the pulleys. This results in unusually good traction characteristics, which were also a reason for successes of the DAFs in rallies. In this case, the cars are raced, generally in scrap-yards, exclusively in reverse gear. The thrust belt uses a large number of V-shaped steel elements retained on two steel bands. Rather than the pulled rubber drive belts as originally used by DAF, the modern transmission is made much more durable by the use of steel link belts that are pushed by their pulleys.

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Therefore, the engine only performs its best at the vehicle speed appropriate to the point of maximum engine torque, power or economy. The same situation also repeats when the torque output and fuel economy, the other two performance factors, are considered. Of course the daf could hit around 75mph backwards as well as forwards.

In addition, to the varioamtic axle there is, on the left and on the right, another fixed gear-ratio. Another cutaway, this time showing the DAF While many of the problems with automatics have now been overcome, wind the clock back and there were limits to what a torque converter could do and the transmission designer faced the problem of matching the available gear ratios to the needs of the car as best they could. In transmissiion DAF company introduced a development by Johan van der Brugghen, indeed, it was based on much older inventions.

Control of the pulley running diameters, and therefore the drive ratio, was achieved through servos operated by an inlet manifold vacuum. The attainment of the constant engine speed required to achieve any one of the three performance factors is not possible with a conventional gearbox, because the engine speed is required to be continually changed to match the vehicle speed.

Variomatic – Wikipedia

In practice, it would not have been too difficult to arrange the governing of the engine to ensure that it maintained peak torque. The distance between the drums is controlled by the engine vacuum in the inlet manifold and engine RPMthrough centrifugal weights inside the drums.

Between the two pulleys runs a drive belt. The Variomatic transmission had six major components: Notify me of new comments via email. For valve timing system, see Valvematic.

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The CVT offers the driving comforts associated with an automatic gearbox as well as the efficiency of a manual transmission, transmissino any loss of vehicle performance. My other one is better maintained.

Variomatic Transmission Catalogue – Automatic Choice

When the car was pulling away from rest the engine’s torque needed to be considerably multiplied – in other words the engine had to turn faster than the car’s wheels.


By rotating a small hand wheel positioned next to the fuel tank, the running diameter of the drive pulley could be varied to alter the gear ratio. Of the front tapered-disc pairs, those on the inside are fixed, and the outside ones are movable through the engine vacuum, which can be clearly seen by the vacuum-pipe connection. When suddenly accelerated, then through the altered inlet manifold vacuum, the front discs move apart- and the rear discs towards each other.

They launched a new CVT system in using a segmented steel thrust belt. The movement of the pulleys are controlled by manifold pressure. Therefore, the driving pulleys needed to have a small diameter, while that of the vafiomatic pulleys had to be large.

Thereby, the RPMs remain just as high as when the throttle valve is opened. This entry was posted in Uncategorized.

Variomatic Transmission Catalogue

When the car was underway there was less necessity to multiply the engine’s torque, so if the driving pulley’s diameter could be made to expand and the driven pulley’s diameter to contract, an efficient ratio for the new condition would result. It was the first commercially successful CVT as opposed to shifting between separate gears.

As a C ontinuously V ariable T ransmission, the transmissoon belongs to the infinitely variable transmissions and the principle is found, in a simplified form, varjomatic scooters and vehicles with a similar drive system. At low speeds the output is very less. Within the car, the transmission is simply a shift that puts the car in either forward or reverse. This lever shifts the axle drive shaft coming from the engine in the front distributor casing, thus causing a second conical gearwheel to mesh, which reverses the rotation direction back up to the maximum speed.

This was achieved by the Variomatic. You are commenting using your Facebook account. Manual transmission remains dominant in Europe. As a result, I looked through my library to see what I could find out about the transmissions in the DAF cars.

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