Classification by tooth shape: The tooth shape of gears includes tooth profile curve, pressure angle, tooth height and displacement. Involute gears are relatively easy to manufacture, so among the gears used in modern times, involute gears account for the absolute majority, while cycloidal gears and arc gears are rarely used. In terms of pressure angle, gears with small pressure angles have smaller load-bearing capacity; while gears with large pressure angles have higher load-bearing capacity, but the load on the bearings will increase when the transmission torque is the same, so they are only used in special circumstances.
2. Classification by gear shape: Gears can also be divided into cylindrical gears, bevel gears, non-circular gears, racks, and worm gears according to their shape.
3. Classification according to tooth line shape: Gears can be divided into spur gears, helical gears, herringbone gears, and curved gears.
4. Classification according to the surface on which the gear teeth are located: Gears can be divided into external gears and internal gears.
5. Classification by manufacturing method: Gears can be divided into cast gears, cut gears, rolled gears, sintered gears, etc.