Patent ID: 8888031

Claim:
A method of deriving a path of contact of a face gear including a plurality of gear teeth in meshing with a pinion gear, the method comprising: positioning the pinion gear for meshing with the face gear a prescribed reference contact position; shifting the pinion gear from the reference contact position either towards or away from the face gear along a rotational axis of the face gear; deriving a first relationship between a rotational angle of the pinion gear and a fluctuation error of a rotational angle of the face gear; deriving a second relationship between the rotational angle of the pinion gear and the fluctuation error by shifting the first relationship by subtracting from the rotational angle an angle of 360 degrees divided by the number of the gear teeth; deriving a third relationship between the rotational angle of the pinion gear and the fluctuation error by shifting the first relationship by adding to the rotational angle the angle of 360 degree divided by the number of the gear teeth; deriving a first point which the first and second relationships share and a second point which the first and third relationships share, the first point having a first fluctuation error, the second point having the first fluctuation error; deriving a third point, which has the first fluctuation error, between the first and second points; and determining a curve line connecting a first contact position, a second contact position, and a third contact position as the path of contact on tooth flanks of the gear teeth of the face gear, setting the first contact position as a contact position of the pinion gear and corresponding to the first point, setting the second contact position as a contact position of the pinion gear and corresponding to the second point, setting the third contact position as a contact position of the pinion gear and corresponding to the third point when the face gear is rotated for an angle for a rotational error.