There are many forms of tooth profiles, among which the involute tooth profile is the most common. There are two common processing methods for involute tooth profiles, namely forming method and generating method.
1. Milling
Using a disc-shaped modulus milling cutter or a finger-shaped milling cutter to mill teeth belongs to the forming method, and the cross-sectional shape of the milling cutter teeth corresponds to the shape between the gear teeth. This method has low processing efficiency and processing accuracy and is only suitable for single-piece small batch production.
2. Forming gear grinding
It also belongs to the forming method. Because the grinding wheel is not easy to trim, it is rarely used.
3. Hobbing
It belongs to the generating method, and its working principle is equivalent to a pair of helical gears meshing. The prototype of the gear hob is a helical gear with a large helical angle. Because the number of teeth is small (usually the number of teeth z = 1), the teeth are very long, and a worm with a small helical angle is formed on the shaft. After slotting and shoveling, it becomes a hob with a cutting edge and a back angle.
4. Shaving
In mass production, shaving is a common finishing method for non-hardened tooth surfaces. Its working principle is to use the gear shaving cutter and the processed gear to freely mesh, and with the help of the relative slip between the two, very fine chips are shaved from the tooth surface to improve the accuracy of the tooth surface. Gear shaving can also form drum-shaped teeth to improve the position of the tooth surface contact area.
5. Gear shaping
Gear shaping is a common gear cutting process using the generating method besides gear hobbing. When shaping, the gear shaping cutter and the workpiece are equivalent to the meshing of a pair of cylindrical gears. The reciprocating motion of the gear shaping cutter is the main motion of the gear shaping, and the circular motion of the gear shaping cutter and the workpiece in a certain proportional relationship is the feed motion of the gear shaping.
This picture is not intuitive enough, which is not difficult for the editor. The following principle diagram should be clear at a glance.
6. Gear grinding by generating method
The cutting motion of the gear grinding by generating method is similar to gear hobbing. It is a tooth shape finishing method, especially for hardened gears, it is often the only finishing method. The gear grinding by the generating method can be done by using a worm grinding wheel, a conical grinding wheel or a disc grinding wheel.
