When the technical condition of the automobile drive shaft is bad, the amplitude of the bending vibration increases, the vibration is intense, even the body vibrates, and the obvious periodic sound is made, which is called vibration and abnormal sound. With the increase of vehicle speed, the main reason for the vibration and abnormal noise of the transmission shaft is as follows.

1、传动轴总成失去平衡 传动轴总成的装配误差超限、零件尺寸不精确及在使用中的磨损变形等都会使传动轴沿长度方向的质量分布不均匀而造成传动不平衡。不平衡的传动轴在运转中便会产生附加弯矩，附加弯矩的作用不仅会使配合件冲击发响，还会增强传动轴的弯曲振动，使传动轴的振抖和异响更为明显。

1. The unbalance of the assembly error of the assembly of the drive shaft assembly, the inaccuracy of the parts size and the wear and tear in the use will make the transmission shaft unevenly distributed along the length direction, and cause the unbalance of the transmission. The unbalance transmission shaft will produce additional bending moment in operation. The effect of additional bending moment will not only make the joint impact sound, but also enhance the bending vibration of the transmission shaft, so that the shakes and the abnormal sound of the transmission shaft are more obvious.

2、万向节损伤 万向节在使用中的主要损伤是十字轴轴颈和端面磨损及滚针和轴承座孔磨损等。万向节零件的损伤使十字轴配合松旷而产生摆动和轴向窜动，不仅在工作中发出撞击声，而且削弱传动轴的抗弯刚度。传动轴的质量中心更加偏离旋转轴线，从而增强振抖和异响。

2, the main damage of gimbal damage universal joint is the wear of cross shaft journal and end face, wear of needle roller and bearing hole. The damage of the part of the universal joint causes the swing and axial movement of the cross shaft in combination with the loose and open. It not only makes the sound of the impact in the work,www.qinggangbiesh.cn www.changchunbanjia.cn www.linpianjiaoni.com.cn www.liqingqi.com.cn www.shuidaoqiegeji.cn www.jianchajingm.cn but also weakens the bending stiffness of the transmission shaft. The center of mass of the transmission shaft is more deviated from the axis of rotation, thereby enhancing vibration and abnormal noise.

3、传动轴和滑动叉损伤 传动轴轴管弯曲，即增大传动轴弯曲振动的振幅，可使离心力增大，从而造成强烈的振抖和异响。传动轴键齿和滑动叉键槽磨损，由于配合松旷，在工作中会发出撞击声，还会削弱传动轴的抗弯刚度，增强振抖和异响。

3. The bending of the shaft and the shaft of the transmission shaft, that is, to increase the amplitude of the bending vibration of the transmission shaft, can increase the centrifugal force, thus causing strong vibration and abnormal sound. The wear of the key tooth of the drive shaft and the keyway of the sliding fork, because of the matching of loose and loose, the sound of impact will be issued in the work, the bending stiffness of the transmission shaft will be weakened, and the vibration and the abnormal sound will be enhanced.

4、传动轴两端的安装位置改变 对于不等角速万向节传动轴而言，为减小传动轴的振动和保证驱动桥齿轮的匀速转动，必须符合以下2个条件：1)传动轴两端的万向节叉应位于同一平面内；2)输入轴、输出轴与传动轴的两夹角应相等。 传动轴在使用中，由于传动轴键齿和滑动叉键槽磨损，万向节十字轴轴颈与滚针配合松旷等，会使第1条件破坏；而传动轴安装不良、弹性悬架技术状况变化及传动轴的输入轴和输出轴磨损使安装位置改变等，均会使第2条件破坏。 随着等速传动条件的破坏，将使驱动桥主减速齿轮产生冲击，并引起传动轴运转不稳定，增强抖动和异响。

4, the installation position of the two ends of the drive shaft is changed for the unequal speed universal joint drive shaft, to reduce the vibration of the transmission shaft and to ensure the constant rotation of the driving axle gear, it must conform to the following 2 conditions: 1) the universal joint at both ends of the transmission shaft should be in the same plane; 2) the two angle corresponding phase of the transmission shaft, the output axis and the transmission shaft. Wait. In the use of the transmission shaft, the first conditions will be damaged because of the wear of the key gear of the transmission shaft and the keyway of the sliding fork, the cross shaft neck of the universal joint and the needle of the needle roller, and so on, and the transmission shaft is not well installed, the technical condition of the elastic suspension and the wear of the input shaft and the output shaft of the transmission shaft change the position of the installation and so on, all of which will destroy the second conditions. . With the destruction of the constant speed transmission condition, the main deceleration gear of the drive axle will be impacted, and the drive shaft will be unstable in operation, so as to enhance the jitter and abnormal noise.

5、传动轴临界转速降低 传动轴设计时的最高转速一般为临界转速的 0．7倍。但由于传动轴动平衡的破坏、万向节的损伤及中间支承轴承松旷等，都会使传动轴临界转速降低。当临界转速降低到传动轴的转速时，传动轴在运转中便易于产生共振。传动轴共振时的振幅最大，振动剧烈，往往会造成传动轴折断。

5, the critical speed of the transmission shaft decreases, and the maximum speed of the transmission shaft is generally 0.7 times that of the critical speed. However, due to the failure of the transmission shaft's dynamic balance, the damage of the universal joint and the loose bearing of the intermediate bearing, the critical speed of the transmission shaft will be reduced. When the critical speed is reduced to the speed of the transmission shaft, the transmission shaft is easy to generate resonance during operation. When the transmission shaft is resonant, the amplitude is the largest and the vibration is intense.