| 摘要 |
In the strain wave gearing (1), an involute positive deflection tooth profile of a low pressure angle of less than 20° is used as the basic tooth profile for the rigid internal spur gear (2) and the flexible external spur gear (3) in order to increase the effective tooth depth. Noting that the rack tooth profile of an involute tooth profile is a straight line, continuous meshing of the two gears (2, 3) in the tooth trace direction is made possible by shifting the external teeth (11), taking coning into consideration, so that the linear parts of the rack tooth profiles in each transverse cross-section of said external teeth in the tooth trace direction coincide when viewed along the tooth trace direction. The root rim thickness of the front end (19) of the external teeth (11) of the flexible external spur gear (3) is set to an optimal thickness using a revised Goodman diagram and the root rim thicknesses at various positions other than the front end of the external teeth (11) in the tooth trace direction are set to appropriate values using the revised Goodman diagram, taking the root rim thickness of the front end and the amount of shifting into consideration. |
