What are the gear processing methods?

What are the gear processing methods?

Gear is a transmission component that we often see and use in our daily life. In fact, gears are also divided into many types, and different transmission effects can be achieved according to different shapes and types. The following small side describes the gear processing method.

Gear processing method

1. Gear milling

Milling teeth with disc module milling cutter or finger milling cutter belongs to forming processing, and the section shape of milling cutter teeth corresponds to the shape between gear teeth. This method has low processing efficiency and low processing accuracy, and is only suitable for single piece and small batch production.

2. Shape grinding

It also belongs to forming processing. Because the grinding wheel is not easy to repair, it is less used.

3. Gear hobbing

It belongs to the generating method, and its working principle is equivalent to a pair of helical gears meshing. The prototype of gear hob is a helical gear with a large helix angle. Because the number of teeth is small (usually z=1) and the teeth are long, a worm with a small helix angle is formed around the shaft, and then it becomes a hob with cutting edge and back angle through slotting and cutting teeth.

4. Shaving

Shaving is a common finishing method for non-hardening tooth surface in large-scale production. Its working principle is to make use of the free meshing between the shaver and the machining gear, with the help of the relative sliding between the two, to shave fine chips from the tooth surface and improve the accuracy of the tooth surface. Shaving teeth can also form drum-shaped teeth to improve the position of the contact area of the tooth surface.

5. Gear shaping

Gear shaping is a common gear cutting process besides gear hobbing. During gear 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 cutter. The circular motion of the gear shaping cutter and the workpiece in a certain proportion is the feed motion of the gear shaping cutter.

6. Gear grinding by generating method

The cutting motion of generating gear grinding is similar to gear hobbing. It is a method of tooth shape finishing, especially for hardened gear, which is often a finishing method. The generating method can be used for grinding with worm wheel, cone wheel or disc wheel.

7. Broach tooth

The broach tooth is mainly used for drawing internal gears. The final shape of the broach is the same as the complete tooth space of the gear. It is a profiling method. Due to the high manufacturing cost of broach, it is suitable for batch production.

8. Stamping gear

The shape of the punch is the same as that of the complete gear or the complete gear groove. It can punch out the outer gear or the inner gear. It is applicable to batch production.

9. Gear without cutting

1) The final formation or improvement of tooth surface quality by metal plastic deformation or powder sintering can be divided into cold forming processed at normal temperature and hot forming heated to about 1000 ℃. The former includes cold rolling, cold forging, blanking, etc.; The latter includes hot rolling, precision die forging and powder metallurgy

2) Chip-free machining of gears can increase the material utilization rate from 40 aspects of machining to more than 80% to 95%, and the productivity can also be doubled. However, due to the limitation of die strength, generally only pinion or other gear parts can be machined. At the same time, gears with high accuracy requirements still need to use fine tooth shape after cutting

3) The chip-free machining of gears requires special process equipment, and the initial investment is large. Only when the production batch is large (generally more than 10000 pieces) can the production cost be significantly reduced.

Function and structure of gear

Gear is an important transmission part of the machine. Its main function is to connect with shaft parts through flat keys or splines, and then mesh with one or more gears to transfer power and motion from one shaft to another.

The gear is a rotating part, whose structural feature is that its diameter is generally larger than its length, and it is usually composed of an outer cylindrical surface (conical surface), an inner hole, a keyway (spline groove). According to the different structural forms, the gear often has rim, hub, web, orifice plate, spoke and other structures.

According to different structures, gears can be divided into solid type, web type, orifice type, spoke type, etc. If the gear and shaft work together, the gear shaft is formed. There are many types of gears according to their tooth shape and distribution. Common standard gears can be divided into straight cylindrical gears, helical cylindrical gears, bevel gears, etc.