When the technical condition of the automobile transmission shaft deteriorates, the amplitude of the exaggerated vibration increases, the vibration is severe, and even causes the body to vibrate, and emits obvious periodic sounds, which are called vibration and abnormal noise. The main reason for the vibration and abnormal noise of the drive shaft is that the drive shaft of the car is aggravated by the increase of the speed of the vehicle.

There are several aspects as follows.

1. The transmission shaft assembly is unbalanced. The assembly error of the transmission shaft assembly exceeds the limit, the size of the parts is inaccurate, and the wear and deformation in use will all cause quality problems along the length of the transmission shaft.
Uneven distribution results in unbalanced transmissions. The unbalanced drive shaft will generate additional exaggerated torque during operation, and the effect of the additional exaggerated torque will not only make
The impact and sound of the fittings will also enhance the exaggerated vibration of the drive shaft, making the vibration and abnormal noise of the drive shaft more obvious.

2. Damaged universal joint
The main damage of the universal joint in use is the wear of the cross shaft journal and end face, the wear of the needle roller and the bearing seat hole, etc. The damage of the universal joint parts+
The word shaft is loosely fitted, resulting in swinging and axial movement, which not only makes knocking noises during work, but also weakens the anti-exaggeration rigidity of the drive shaft. drive shaft the center of mass is further away from the axis of rotation, which increases chatter and rattle.

3. The drive shaft and the sliding fork are damaged. The shaft tube of the drive shaft is bent, that is, the amplitude of the drive shaft's bending vibration increases, which can increase the centrifugal force, resulting in strong vibration and abnormal noise. spread
Shaft key teeth and slide yoke keyway worn. Because the fit is too loose, there will be a knocking sound during work, and at the same time it will weaken the bending resistance of the transmission shaft and strengthen the bending resistance of the transmission shaft. vibrations and rattles.

4. The installation position at both ends of the drive shaft is changed
For the unequal angular velocity universal joint drive shaft, in order to reduce the vibration of the drive shaft and ensure the uniform rotation of the drive axle gear, the following two conditions must be met:
Health status:

1) The universal joint forks at both ends of the drive shaft should be in the same plane;
2/ The included angles of the input shaft, output shaft, and drive shaft should be equal. When the transmission shaft is in use, due to the wear of the key teeth of the transmission shaft and the keyway of the sliding fork,
Too loose fitting of the cross shaft journal of the steering knuckle and the needle roller will destroy the first condition; as well as poor installation of the drive shaft, changes in the technical condition of the elastic suspension, transmission
The second condition will be destroyed if the input shaft and output shaft of the moving shaft are worn and the installation position is changed. With the destruction of the constant speed transmission condition, it will make
The main reduction gear of the drive axle produces an impact, resulting in unstable operation of the drive shaft, aggravated vibration and abnormal noise.

5. The critical rotational speed of the drive shaft is reduced. The maximum rotational speed of the drive shaft is generally 0.7 times the critical rotational speed. However, due to the damage of the dynamic balance of the drive shaft, the universal joint and the drive shaft are damaged.
Loose support bearings, etc. will reduce the critical speed of the transmission shaft. When the critical speed is reduced to the speed of the propeller shaft, the propeller shaft will
It's easy to resonate. The resonance amplitude of the transmission shaft is the largest, and the vibration is severe, which often causes the transmission shaft to break.