Main gear and axle shafts — design description (Audi A4 B6)

The gearbox transmits the converted engine torque through a small and large (leading) gear wheel to the main gear. The main drive housing is bolted to the large gear wheel. The half-shafts create a power connection between the main gear and the hubs.

Main gear and axle shafts

Main gear: The main transmission is located in one housing together with the differential and the stepped or automatic transmission. The housing also contains four interlocking bevel gears, two of which are connected to the axle shafts.

Straight line movement: Both front wheels rotate at the same speed as the pinion gear. The differential rotates at the same speed, the bevel gears do not rotate.

Moving along a curve: The wheel on the outside of the turn travels a greater distance than the inside wheel. The different rotational speeds of the wheels must be compensated, otherwise the car will move jerkily around the turn and with the front wheels spinning. The bevel gears come into play: the faster rotation of the outer bevel gear acts through both transmission bevel gears on the bevel gear located on the inside of the turn, and this gear begins to rotate more slowly.



Transferring power to the front wheels (from differential) occurs through two axle shafts (articulated shafts). In this case, two types of joints are used: either a constant velocity joint or a tripod joint. In the first case, when the joint is bent, six balls move in specially ground raceways. In this case, at any angle of the shaft bend, uniform transmission of force is ensured. In the tripod joint, instead of six balls, there are three rollers on needle bearings. These joints reduce the transmission of vibrations from the drive to the body.

In a four-wheel drive vehicle the drive force from the engine is transmitted to the center differential, and from the differential to the front and rear axles. To drive the rear wheels in a four-wheel drive model, as in a car with rear wheel drive, there must be an additional cardan shaft, a differential and rear axle half-shafts. The center differential automatically and purely mechanically regulates the distribution of force between both axles. If the axles rotate at different speeds, the differential locks automatically. Maintenance of the center differential is not provided, it serves for the entire service life of the car.

This article was copied from the website: Audimanual.ru