Owing to the spline connection transmission has a large contact area, high bearing capacity, centering performance and good guiding performance, shallow keyway, small stress concentration, small weakening of the strength of the shaft and hub, and tight structure. Therefore, it is often used for static transmission of large torque and high centering accuracy requirements of links and dynamic links.

According to the shape of spline teeth, it can be divided into two categories: angular spline and involute spline. It can be divided into rectangular splines and triangular splines. From the current application point of view, the involute spline most, followed by rectangular splines, mostly triangular splines on loading and unloading tools.

Rectangular spline

Rectangular spline is easy to process, high precision can be obtained by grinding, but internal splines usually use splines. The broach cannot be processed for splines with no through holes, and has to be processed by plunge cutting, which has low precision.

At present, the relevant standards of China, Japan and Germany are as follows: China GB1144-87: Japan JIS B1601-85: German SN742 (German SMS factory standard): six-slot rectangle of American WEAN company spline standard.

Involute spline

The tooth profile is involute, and there is radial component force on the gear teeth when loaded, which can play a centering role, so that each tooth has a uniform load, high strength and long life. The processing technology is the same as that of the gear, the tool is more economical, and it is easy to obtain high precision and interchangeability. It is used for couplings with larger loads, higher centering accuracy requirements, and larger sizes. Widely used, the main standards at home and abroad are as follows: China GB/(substitute, equivalent IS04156-1981: Japan JISB1602-1992JISD2001-1977: Germany DIN5480DIN5482: United States.

Triangular spline

The tooth shape of the internal spline is triangular, and the tooth profile of the external spline is an involute with a pressure angle equal to 45°. It is easy to process, and the teeth are small and numerous, which is convenient for the adjustment and assembly of the mechanism. For the shaft and the hub: the weakening is minimal. It is mostly used for light load and small diameter static connection, especially for the connection between shaft and thin-walled parts. The main standards are: Japan JISB1602-1991: Germany DIN5481