Front wheel drive design features

Front wheel drives consist of internal 6 (pic. 1) and outer 1 constant velocity joints (SHRUS), connected by shafts 5. The external hinge allows only angular movements of the connected shafts. The internal hinge, in addition to the angular ones, provides axial displacement of the shafts when the front wheels are turned and the suspension is working.



The Beerfield-type external joint consists of a body, a cage, a cage and six balls. Grooves are made in the hinge body and in the holder to accommodate the balls. The grooves in the longitudinal plane are made along the radius, which provides the required angle of rotation of the outer hinge. The splined tip of the outer hinge housing is installed in the front wheel hub and attached to it with a nut.


The holder of the outer hinge is mounted on the splines of the shaft 5 and fixed on the shaft with a retaining ring.

The internal hinge of the Lebro type of a car with a manual transmission differs from the external one in that the tracks of the cage body are straight, and not radial, which allows the parts of the hinge to move in the longitudinal direction. The splined tip of the inner joint housing is fixed in the side gear of the differential with a snap ring.

The inner hinge of the Tripod type of a car with an automatic transmission consists of a body and three rollers on needle bearings, put on the trunnions of a three-stud hub. Grooves for rollers are made in the hinge body. The three-spike hub is fixed on the shaft with a retaining ring, the rollers allow the hub to move in the grooves of the hinge body in the axial direction, so that the drive can lengthen or shorten to compensate for the mutual movements of the suspension and the power unit. The splined tips of the bodies of the internal hinges are fixed in the side gears of the differential in the same way as for the hinges of the Lebro type.

To reduce torsional vibrations and vibrations, a rubber damper 7 is pressed onto the shaft of the right drive.

Balls of the same sorting group are installed in Bierfield and Lebro type hinges. All parts of the hinge are selectively matched to each other, so it is impossible to repair the hinge by replacing individual parts, only the hinge assembly and a small repair kit are supplied as spare parts, including a retaining ring, a boot and boot clamps, and in some cases, grease.


The Tripod type internal hinge is supplied as spare parts in the form of two repair kits: a large one, which includes all hinge parts, and a small one, containing a retaining ring, a cover, cover fastening clamps and, in some cases, grease.

To lubricate the hinges, a special grease with molybdenum disulfide is used (domestic analogue - SHRUS-4). The cavities of all hinges are protected from road dirt and water by rubber corrugated covers 3, fixed on the hinge bodies and on the drive shafts with large 2 and small 4 clamps, respectively.

External and internal hinges of equal angular speeds of both drives are the same. However, since the drive shafts differ in length, the right and left wheel drives are not interchangeable.

Note. The drive hinges are very durable, their design life is almost equal to the life of the car. However, in operation they are changed or repaired quite often due to damage to the protective covers. Such work is quite expensive and laborious. In order to save a lot of money, regularly check the condition of the protective covers of the hinges and immediately replace them at the slightest damage. If water or dust gets into the hinge through a damaged cover, it will fail after several hundred kilometers. The sealed hinge wears out extremely slowly.