A spline shaft is a mechanical transmission device. Like flat, semicircular, and oblique keys, they all transfer mechanical torque. The shaft surface has a longitudinal keyway, and the rotating parts of the shaft also have corresponding keyway, which can be kept in sync with the shaft rotation. While rotating, some gears can also slide lengthwise on the shaft, such as gearbox shift gears.There are two kinds of spline shafts: rectangular spline shafts and involute spline shafts. Rectangular spline shafts are widely used in spline shafts, while involute spline shafts are used for connection with large loads, high alignment accuracy and large dimensions. Rectangular spline shafts are commonly used in aircraft, automobiles, tractors, machine tool manufacturing, agricultural machinery, general mechanical drives, etc. Because the rectangular spline shaft has multiple teeth, it has high bearing capacity, good neutrality and orientation, and its shallow roots can reduce stress concentration. In addition, the spline shaft shaft and hub strength reduction degree is smaller, more convenient processing. The grinding method can achieve higher accuracy. Involute spline shafts are used for connection with large loads, high middle precision and large dimensions. Its characteristic: tooth shape involute, the radial force is produced on the tooth when loading, can play the role of automatic centering, so that the force on each tooth is even, the strength is high, the service life is long, the processing technology is the same as the gear, easy to obtain high precision and interchangeability.Rectangular spline shafts are widely used in aircraft, automotive, tractor, machine tool manufacturing, agricultural machinery and general mechanical drives. Features: multi-tooth machining, high bearing capacity, to neutral, good guidance, shallow roots, small stress concentration, axis and hub strength weakened small, easy processing, high grinding accuracy. There are two series (light series and medium series) in the standard.