The diagram shows the variation trend of gear crest height coefficient when the number of teeth (Z1=31, Z2=32), modulus (m=6), pressure angle (a=20 degrees) and displacement coefficient (x1=x2=0) remain unchanged in gear transmission.

It can be seen from the diagram that the crest height coefficient has no effect on the theoretical engagement line length when other parameters remain unchanged, and the starting position of engagement line has changed, but has no effect on the bending shape of sliding rate curve.With the increase of gear crest height coefficient, the actual engagement line length of the gear increases, i.e. the sliding rate at the top of the gear root increases.