The transmission shaft is generally provided with a sliding spline composed of a sliding fork and a spline shaft to realize the change of transmission length. In order to reduce the axial sliding resistance and wear of sliding spline, sometimes the spline teeth are phosphated or sprayed with nylon layer; Some put rolling elements such as needle, roller or ball in the spline groove to replace sliding friction with rolling friction to improve transmission efficiency. However, this structure is complex and the cost is high. Sometimes, for transmission with severe impact load, elastic transmission shaft is also used. The spline on the transmission shaft shall be provided with lubrication and dust-proof measures. The clearance between the spline teeth and the keyway shall not be too large, and shall be assembled according to the corresponding marks to avoid damaging the dynamic balance of the transmission shaft assembly.

 

The length and included angle of the transmission shaft and their variation range are determined by the vehicle general layout design. The design shall ensure that when the length of the transmission shaft is at the maximum, the spline sleeve and the shaft have sufficient matching length; At the minimum length, it does not die. The included angle of transmission shaft directly affects the service life of universal joint spider and needle roller bearing, the efficiency of universal transmission and the non-uniformity of spider rotation.

 

The transmission shaft is used with various host products, and the surrounding working environment is complex, such as temperature, humidity, water, steam, dust, sand, oil, acid, alkali, corrosive medium, salt water, radiation and so on. It is one of the important factors that must be considered when selecting the coupling. For the working quality of high temperature, low temperature, oil, acid and alkali media, the flexible coupling with general rubber as elastic element material should not be selected, and the flexible coupling with metal elastic element should be selected, such as diaphragm coupling, serpentine spring coupling, etc.