# Establishment of meshing coordinate system of helical gear

When the generating method is used to process helical gear, the main parameters are determined first: the rotation direction of tool and helical gear, and the transmission ratio of gear. Because the tooth surface of helical gear is obtained by the tooth surface of the tool, the tooth surface equation of helical gear is obtained by the method of coordinate system transformation.

As shown in the figure, SA (OA, Xa, ya, ZA) and Sm (OM, XM, YM, ZM) are two fixed coordinate systems, and SS (OS, XS, ys, ZS) and S2 (O2, X2, Y2, Z2) are two dynamic coordinate systems, which are respectively on the tool gear and helical gear. included angle φ S is the rotation angle of the tool’s moving coordinate system SS around the coordinate axis ZS, including the angle φ 2 is the rotation angle of the dynamic coordinate system S2 of the processed helical gear around the coordinate axis Z2. γ M represents the included angle between the tool axis ZS and the processed helical gear axis Z2, γ m = 90° 。

Scroll to Top