Involute spline shafts are used for connections with large loads, high centering accuracy requirements, and large dimensions. In addition, the strength of the shaft and hub of the spline shaft is weakened, and the processing is more convenient, and higher precision can be obtained by grinding.
Its characteristics: the tooth profile is involute, and there is radial force on the teeth when loaded, which can play a self-centering function, so that each tooth is uniformly stressed, has high strength and long life, the processing technology is the same as that of the gear, and it is easy to obtain higher precision and interchangeability.
Spline processing methods: There are many processing methods for spline shafts. It mainly adopts cutting processing methods such as hobbing, milling and grinding, and also can adopt plastic deformation processing methods such as cold hammering and cold rolling.
1. Hobbing method: Use the spline hob to process the spline shaft milling machine or gear hobbing machine according to the generative method. This method has high productivity and precision and is suitable for mass production.
2. Milling method: On the universal milling machine, use a special forming milling cutter to directly mill the contour between teeth, and use an indexing head to separate teeth by tooth-by-tooth milling; if the forming milling cutter is not used, two disc milling cutters can also be used to mill one tooth at the same time On both sides, after milling tooth by tooth, use a disc milling cutter to slightly trim the bottom diameter. The productivity and accuracy of the milling method are low, and it is mainly used for processing spline shafts centered on the outer diameter in single-piece small batch production and roughing before hardening.
3. Grinding method: Grind the spline tooth side and bottom diameter on the spline shaft grinder with a formed grinding wheel, which is suitable for processing hardened spline shafts or spline shafts with higher precision requirements, especially spline shafts centered on the inner diameter.
4. Cold method: It is carried out on a special machine tool. The two heads arranged symmetrically on the outer side of the circumference of the workpiece rotate at a constant speed ratio with the indexing and rotary motion of the workpiece and the axial feed. Each time the workpiece rotates by 1 tooth, the forming wheel on the head matches the tooth groove of the workpiece Hammering once, under the continuous hammering of the high-speed and high-energy movement of the beating wheel, the surface of the workpiece is plastically deformed to form a spline. The accuracy of cold hammering is between milling and grinding, and the efficiency is about 5 times higher than that of milling. Cold hammering can also improve material utilization.