The size of the gear is mainly determined by the precision gear module. The gear module is a basic parameter that measures the size of the gear through artificial abstraction. Mainly to standardize gear cutters and reduce outlay costs. The modules of spur gears, helical gears and bevel gears can refer to the standard module series. If the number of teeth of the gear is constant, the larger the module of the precision gear, the larger the radial dimension of the gear.
The standard of precision gear module is mainly formulated according to the requirements of design, manufacture and inspection. For non-spur gears, the module is different from the common module mn, face module ms and axial module mx. They are all based on the ratio of their respective pitches (normal pitch, face pitch and axial pitch) to pi, and are all in millimeters. The bevel gear module can be divided into the big end module me, the average module mm and the small end module m1, the tool also has the corresponding tool module, the standard module is widely used. In precision gear drives, worm drives, synchronous belt drives, gear couplings and other parts, the standard modulus is a basic parameter.