The spline connection consists of an inner spline and an outer spline. Both the inner and outer splines are multi toothed parts, with the splines on the inner cylinder surface being the inner splines and the splines on the outer cylinder surface being the outer splines. Obviously, spline connections are the numerical development of parallel key connections.

The types of commonly used spline shafts on the market can be roughly divided into three types: one is the rectangular spline shaft, which is widely used in machinery such as machine tools, automobiles, airplanes, etc; Another type is the involute spline shaft, which is mainly used for links with high centering accuracy requirements, large loads, and large dimensions; The third type is triangular splines, used for connecting thin-walled parts.

Usage characteristics: Due to differences in structural form and manufacturing process, compared with flat key connections, spline connections have the following characteristics in terms of strength, process, and use:

Because more teeth and grooves are directly and uniformly produced on the shaft and hub hole, the coupling force is relatively uniform;

Due to the shallow groove, the stress concentration at the tooth root is relatively small, and the strength of the shaft and hub is weakened less;

With a larger number of teeth and a larger total contact area, it can withstand larger loads;

The alignment between the components on the shaft and the shaft is good, which is important for high-speed and precision machines;

Good guidance is important for dynamic connections;

Grinding methods can be used to improve machining accuracy and connection quality;

The manufacturing process is complex and sometimes requires specialized equipment, resulting in higher costs.

Applicable occasions: Connections that require high centering accuracy, transmit large torque, or frequently slip.

Most of the spline shafts seen on the market are made of 40Cr material, with a surface hardness requirement of HRC45-50 and requiring heat treatment.