Gear manufacturers teach you gear related terms and definitions

1.Standard gear

a) Definition: both sides of the gear face with ring groove is the standard gear.

b) Function: transfer the rotation of one shaft to another, and also realize the actions of deceleration, growth, direction change and direction change.

c) Structure: gear tooth, tooth slot, end face, normal face, tooth top circle, tooth root circle, base circle, graduation circle

2.Gear base

a) The gear base surface refers to the end face of one side of the gear. When turning the end face after the gear is clamped once, the inner hole of the gear is turned at the same time, that is, the end face formed by turning the inner hole and the end face with one knife.

3. End face

The plane at both ends of the gear.

4.Inner ring end face

a) The flange on both sides of the gear near the inner hole is the inner ring end face.

5.Outer ring end face

a) The flange on both sides of the gear near the outer circle of the gear is the outer ring end face.

6.Flange of gear face

a) After the ring grooves are installed on the end faces of both sides of the gear, two flanges are generated with the ring grooves as the dividing line.

7.Gear face ring groove

a) Definition: ring groove on both sides of gear end face.

b) Function:

① avoid space use, reduce assembly contact surface and ensure assembly accuracy?

② The ring groove on the non base side is used to avoid the threaded hole, and the diameter of the ring groove shall be larger than the threaded hole.

8. Gear teeth

a) Referred to as tooth, it is every convex part on the gear used for meshing. These convex parts are generally arranged radially. The teeth on the matched gear contact each other, which can make the gear continuously meshed and operated.


a) The space between two adjacent teeth on a gear; the end face is a plane perpendicular to the axis of the gear or worm on a cylindrical gear or worm.

10.Normal plane

a) Refers to a plane perpendicular to the tooth line of a tooth.

11.Addendum circle

a) Refers to the circle at the top of the tooth.

12.Radicle circle

a) Refers to the circle at the bottom of the groove.

13.Base circle

a) The generating line of the involute is a pure rolling circle.

14.Index circle

a) It is the reference circle for calculating the geometric dimension of the gear in the end face.