The front and rear axles of many heavy-duty vehicles have always further increased the reduction ratio of the drive axle, and even added wheel reducers. In the UK, many buses use a worm wheel type single-stage final drive in the front and rear axle assemblies.
When a car is turning or driving on uneven roads, the travel of the left and right wheels of the front and rear axle assembly of a heavy-duty vehicle at the same time is not equal, so their speeds should also be different. In addition, even if the car is driving straight on a flat road, the left and right wheel strokes of the front and rear axle assembly of the car are the same, sometimes due to the manufacturing error of the tire outer diameter, the degree of tread wear, the tire pressure or the tire load, etc. Cause their rolling radii to be unequal, resulting in different speeds.
Therefore, the front and rear axle assemblies of heavy-duty vehicles require that the drive axle transmits torque to the left and right drive wheels, while enabling them to rotate at different angular velocities that meet the above-mentioned kinematic requirements. This requirement is fulfilled by the differential. The simple symmetrical conical planetary gear differential has been widely used in various automobiles due to its simple structure and stable and reliable operation.
If the internal friction is not taken into account, the differential of the front and rear axle assembly of this heavy-duty vehicle evenly distributes the torque to the left and right half shafts. Therefore, when a car equipped with this simple symmetrical conical planetary gear differential has different adhesion coefficients between the left and right driving wheels and the road, and one driving wheel slips and loses traction, the other is attached to the front and rear axles of the heavy vehicle. The drive wheels of the assembly will also lose traction.
In this case, the front and rear axles of heavy-duty vehicles always improve the passing ability of off-road vehicles. Differential locks can be used to lock the left and right axle shafts together; Self-locking differentials such as the gear type and free wheel type of the friction plate, so that the torque of the drive axle can be transmitted to the non-slip drive wheels as much as possible, so as to make full use of the adhesion of the drive wheels to produce Sufficient traction to enable the car to continue driving.
