汽車傳動軸的技術狀況變壞時，彎曲振動的振幅增大，振動劇烈，甚至引起車身振抖，并發出明顯的周期性響聲，即稱為振抖和異響汽車傳動軸隨著車速的增高而加劇，傳動軸產生振抖和異響的主要原因有以下幾個方面。

When the technical condition of the automobile transmission shaft deteriorates, the amplitude of bending vibration increases, the vibration is severe, and even causes the body to vibrate and produce obvious periodic sounds, which are called vibration and abnormal noise. The automobile transmission shaft intensifies with the increase of vehicle speed, and the main reasons for the vibration and abnormal noise of the transmission shaft are as follows.

傳動軸總成失去平衡

Transmission shaft assembly out of balance

傳動軸總成的裝配誤差超限、零件尺寸不精確及在使用中的磨損變形等都會使傳動軸沿長度方向的質量分布不均勻而造成傳動不平衡。不平衡的傳動軸在運轉中便會產生附加彎矩，附加彎矩的作用不僅會使配合件沖擊發響，還會增強傳動軸的彎曲振動，使傳動軸的振抖和異響更為明顯。

The assembly error of the transmission shaft assembly exceeds the limit, the size of the parts is not accurate, and the wear and deformation during use can cause uneven distribution of mass along the length direction of the transmission shaft, resulting in transmission imbalance. An unbalanced transmission shaft will generate additional bending moments during operation. The effect of the additional bending moment not only causes the mating parts to impact and make noise, but also enhances the bending vibration of the transmission shaft, making the vibration and abnormal noise of the transmission shaft more obvious.

萬向節損傷

Universal joint damage

萬向節在使用中的主要損傷是十字軸軸頸和端面磨損及滾針和軸承座孔磨損等。萬向節零件的損傷使十字軸配合松曠而產生擺動和軸向竄動，不僅在工作中發出撞擊聲，而且削弱傳動軸的抗彎剛度。傳動軸的質量中心更加偏離旋轉軸線，從而增強振抖和異響。

The main damage to the universal joint during use is the wear of the cross shaft journal and end face, as well as the wear of the roller needle and bearing seat hole. The damage to the universal joint components causes the cross shaft to fit loosely, resulting in swinging and axial displacement. This not only makes a collision sound during operation, but also weakens the bending stiffness of the transmission shaft. The center of mass of the transmission shaft deviates further from the rotational axis, thereby enhancing vibration and abnormal noise.

傳動軸和滑動叉損傷

Damage to transmission shaft and sliding fork

傳動軸軸管彎曲，即增大傳動軸彎曲振動的振幅，可使離心力增大，從而造成強烈的振抖和異響。傳動軸鍵齒和滑動叉鍵槽磨損，由于配合松曠，在工作中會發出撞擊聲，還會削弱傳動軸的抗彎剛度，增強振抖和異響。

Bending of the transmission shaft tube, which increases the amplitude of the bending vibration of the transmission shaft, can increase the centrifugal force, causing strong vibration and abnormal noise. The key teeth of the transmission shaft and the sliding fork keyway are worn, and due to loose fit, there will be a collision sound during operation, which will weaken the bending stiffness of the transmission shaft, enhance vibration and abnormal noise.

傳動軸兩端的安裝位置改變

Change in installation position at both ends of the drive shaft

對于不等角速萬向節傳動軸而言，為減小傳動軸的振動和保證驅動橋齒輪的勻速轉動，必須符合以下2個條件：

For unequal angular velocity universal joint drive shafts, in order to reduce vibration of the drive shaft and ensure uniform rotation of the drive axle gears, the following two conditions must be met:

傳動軸兩端的萬向節叉應位于同一平面內；

The universal joint forks at both ends of the transmission shaft should be located in the same plane;

輸入軸、輸出軸與傳動軸的兩夾角應相等。 傳動軸在使用中，由于傳動軸鍵齒和滑動叉鍵槽磨損，萬向節十字軸軸頸與滾針配合松曠等，會使1條件破壞；而傳動軸安裝不良、彈性</a懸架技術狀況變化及傳動軸的輸入軸和輸出軸磨損使安裝位置改變等，均會使第2條件破壞。 隨著等速傳動條件的破壞，將使驅動橋主減速齒輪產生沖擊，并引起傳動軸運轉不穩定，增強抖動和異響。

The angle between the input shaft, output shaft, and transmission shaft should be equal. During use, the transmission shaft may be damaged due to wear on the key teeth and sliding fork keyway, as well as loose fit between the universal joint cross shaft neck and the rolling needle; Poor installation of the transmission shaft, changes in suspension technology due to elasticity, and changes in the installation position caused by wear of the input and output shafts of the transmission shaft can all cause the second condition to be damaged. With the destruction of constant speed transmission conditions, it will cause impact on the main reduction gear of the drive axle, and cause unstable operation of the drive shaft, enhancing vibration and abnormal noise.

傳動軸臨界轉速降低

The critical speed of the transmission shaft decreases

傳動軸設計時的高轉速一般為臨界轉速的 0．7倍。但由于傳動軸動平衡的破壞、萬向節的損傷及中間支承軸承松曠等，都會使傳動軸臨界轉速降低。當臨界轉速降低到傳動軸的轉速時，傳動軸在運轉中便易于產生共振。傳動軸共振時的振幅大，振動劇烈，往往會造成傳動軸折斷。

The high speed during the design of the transmission shaft is generally 0.7 times the critical speed. However, due to damage to the dynamic balance of the transmission shaft, damage to the universal joint, and looseness of the intermediate support bearing, the critical speed of the transmission shaft will decrease. When the critical speed drops to the speed of the drive shaft, the drive shaft is prone to resonance during operation. When the transmission shaft resonates, the amplitude is large and the vibration is severe, often causing the transmission shaft to break.