According to the structure, the drive axle can be divided into three categories:
1. Central single-stage reduction drive axle
It is the simplest type of drive axle structure, and it is the basic form of drive axle, which is dominant in heavy-duty trucks. Generally, when the main transmission ratio is less than 6, the central single-stage reduction drive axle should be used as much as possible. The central single-stage reducer tends to adopt a hyperbolic helical bevel gear, the driving pinion adopts a horse-riding support, and a differential lock device is available for selection.
2. Central double-stage reduction drive axle
In the domestic market, there are two main types of central two-stage drive axles: one type of rear axle design for trucks, such as Eaton series products, has reserved space in the single-stage reducer in advance. When compared, a cylindrical planetary gear reduction mechanism can be installed to change the original central single-stage into a central two-stage drive axle. This kind of restructuring has a high degree of “three transformations” (ie serialization, generalization, and standardization), and the axle housing, main deceleration The bevel gears can be used in general, and the diameter of the bevel gears remains unchanged; for another type of products such as the Rockwell series, when the traction force and speed ratio are to be increased, the first-stage bevel gear needs to be remade, and then the second-stage cylindrical spur gear is installed. Or helical gears, and become the required central double-stage drive axle. At this time, the axle housing can be used universally, and the main reducer is not. There are 2 specifications of bevel gears.Since the above-mentioned central double-stage reduction axles are all models derived as a series of products when the speed ratio of the central single-stage axle exceeds a certain value or the total traction mass is large, it is difficult for them to be transformed into front drive axles. Therefore, in general, the two-stage reduction axle is generally not developed as a basic drive axle, but exists as a drive axle derived from a special consideration.
3. Central single-stage, wheel-side reduction drive axle
Wheel deceleration drive axles are widely used in off-highway vehicles and military vehicles such as oil fields, construction sites, and mines. The current wheel side reduction axle can be divided into two categories: one is the conical planetary gear wheel side reduction axle; the other is the cylindrical planetary gear wheel side reduction drive axle. The conical planetary gear wheel-side reduction bridge is a wheel-side reducer composed of a conical planetary gear transmission. The wheel-side reduction ratio is a fixed value of 2. It is generally composed of a series of central single-stage bridges. In this series, the central single-stage axle is still independent and can be used alone. It is necessary to increase the output torque of the axle to increase the traction force or increase the speed ratio. The conical planetary gear reducer can be turned into a two-stage bridge. The difference between this type of axle and the central two-stage reduction axle is:Reduce the torque transmitted by the half shaft, and directly increase the increased torque to the wheel reducer at the two shaft ends, which has a higher degree of “three transformations”. However, this type of bridge has a fixed wheel-side reduction ratio of 2. Therefore, the size of the central final reducer is still relatively large, and is generally used for road and off-highway military vehicles. Cylindrical planetary gear type wheel side reduction bridge, single row, ring gear fixed type cylindrical planetary gear reduction bridge, the general reduction ratio is between 3 and 4.2. Due to the large wheel side reduction ratio, the speed ratio of the central main reducer is generally less than 3, so that the large bevel gear can take a smaller diameter to ensure the ground clearance requirements of heavy trucks. This type of axle is larger in quality and more expensive than the single-stage reducer, and has a gear transmission in the wheel valley, which will generate a lot of heat and cause overheating when driving on the road for a long time; therefore, as a drive axle for road vehicles, it is Not as good as the central single-stage reduction axle.
Post time: Nov-01-2022