As shown in Figure 1, R is the radius of involute gear indexing circle, Rb is the radius of base circle, ry is the radius of any circle, RA is the radius of tooth top circle, RF is the radius of tooth root circle, ly is the thickness of spiral teeth on any circle, l is the thickness of spiral teeth on indexing circle, a is the pressure angle on involute gear indexing circle, and ay is the pressure angle on any circle, θ Is the involute angle on the dividing circle, θ Y is the involute angle on any circle.
According to the basic principle and calculation diagram of involute gear, the thickness of spiral teeth on any circle ly:
In the formula θ， θ Y is expressed in radians, where:
Basic parameters of involute gear: RB = mzcosa, r = MZ, RA = R + MHA, RF = R-M (HA + HF), where m is the module of involute gear, Z is the number of involute gear teeth, ha is the tooth height coefficient, HF is the tooth top coefficient, then the area of single tooth s tooth:
As shown in Figure 2, it can be concluded that:
