Definition, function, and classification of car chassis axle

Author: Auto Repair Handbook

Link: https://zhuanlan.zhihu.com/p/28855527

Source: Zhihu

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1、 The definition of a car axle is that the car axle (also known as an axle) is connected to the frame (or load-bearing body) through suspension, with wheels installed at both ends. 2、 The function of the axle is to transmit force and torque between the frame and the axle (wheels) through the suspension, not the axle. The function of the axle is to bear the load of the car and maintain its normal operation on the road. 3、 The classification of vehicle axles is based on different driving modes, and they are also divided into four types: steering axle, drive axle, steering drive axle, and support axle. Both the steering axle and the support axle belong to the driven axle. Most cars use front rear drive (FR), so the front axle serves as the steering axle and the rear axle serves as the driving axle; For front wheel drive (FF) cars, the front axle becomes the steering drive axle, while the rear axle serves as the supporting axle. 1. Steering axle refers to the vehicle axle that undertakes the steering task. The front axle of a typical car is the steering axle. The front and rear axles of a four-wheel steering car are all steering axles. It uses the steering knuckles in the axle to deflect the wheels at both ends by a certain angle, in order to achieve the steering of the car. It not only bears the vertical load of the car, but also bears longitudinal and lateral forces, as well as the moments caused by these forces. 2. The drive axle is a mechanism located at the end of the transmission system that can change the speed and torque from the transmission and transmit them to the drive wheels. The drive axle is generally composed of the main reducer, differential, wheel drive device, and drive axle housing. The steering drive axle also has a constant velocity universal joint. In addition, the drive axle also needs to withstand vertical forces, longitudinal and lateral forces, as well as braking torque and reaction forces acting between the road surface and the frame or body of the vehicle. 3. The front axle of many sedans and all wheel drive off-road vehicles is both a steering axle and a drive axle, known as a steering drive axle. 4. Support axle: A vehicle axle that has neither steering nor driving functions. The rear axle of a front wheel drive sedan is a typical supporting axle. Mainly composed of rear axle welding assembly, rubber metal support seat, rear wheel assembly and other components. The front end of the rear axle welding assembly is hinged to the vehicle body through a rubber metal support seat, and the longitudinal arm is welded together with the rear axle welding assembly. Its rear end is connected to the rear wheel hub and shock absorber. When the car is in motion, the rear wheel and rear axle welded assembly rotate relative to the vehicle body with rubber metal support seats as the pivot points.