A: Core Mechanism of An Differential Assy
Generally, Assembled into a complete assembly and then installed in the drive axle housing.
1. Differential housing: Usually composed of two halves connected by bolts on the left and right, it forms
an integral cavity used to accommodate planetary gears and half shaft gears. It is the load-bearing component
for power input.
2. Planetary gears: Usually there are 2 to 4, installed on the planetary gear shaft. They can not only rotate
around their own axes (self-rotation), but also revolve along with the differential housing, which is the key to
achieving the difference between the left and right wheels.
3. Planetary gear shaft: Also known as the cross shaft, it is fixed on the differential housing and is used to
install and support the planetary gears.
4. Half shaft gears: one on each side, meshing with the planetary gears. They have splines inside, which are
used to connect with the external splines of the half shaft, thereby transmitting power to the drive wheels.
5. Gear thrust gasket: Installed on planetary gears, half shaft gears and differential housings
B: Power Input and Output Components
1. Driven bevel gear: Also known as cone gear, it is fixed and installed on the differential housing through
bolts. It receives power from the driving bevel gear and drives the entire differential assembly to rotate.
2. Half shafts: One on each side. One end is connected to the half shaft gear through splines, and the other
end is connected to the drive wheel through flanges or splines, ultimately transmitting power to the wheels.
C: Supporting and fixing components
1. Differential bearings: Usually, there are two large tapered roller bearings, which are respectively press-fitted
on both sides of the differential housing. They are installed on the bearing housing of the drive axle housing to
support the entire differential assembly, enabling it to rotate smoothly.
2. Bearing adjustment nut/gasket: It is used to adjust the preload of the differential bearing to ensure that the
differential assembly does not have excessive axial movement while rotating smoothly.
3. Bolts and locking parts: These include bolts connecting the differential housing, bolts fixing the driven bevel
gears, and locking plates for the bearing nuts, etc., to ensure that all components do not loosen during high-speed
rotation.
In practice, the differential assembly is usually integrated with the main reducer and is collectively referred to as
the "drive axle" or "rear axle assembly". The main reducer is composed of a driving bevel gear and a driven bevel gear.
Its main function is to reduce the rotational speed, increase the torque, and rotate the power transmission direction
by 90 degrees.
D: Common fault points
1. Gear wear: especially planetary gears and half shaft gears.
2. Gasket wear: It causes excessive gear clearance and abnormal noise.
3. Bearing damage: Causes poor rotation, overheating or noise.
4. Oil leakage: The aging of the oil seal causes the leakage of lubricating oil, accelerating internal wear.
