FLEXIBLE EXTERNALLY TOOTHED GEAR FOR WAVE GEAR DEVICE

摘要

A cup-shaped flexible externally toothed gear (3) of a wave gear device (1), wherein a diaphragm plate (6) slopes from a diaphragm internal peripheral edge portion (6a) contiguous to a boss part (5) toward a diaphragm external peripheral edge portion (6b) contiguous to a cylindrical body portion (7) in a direction in which the diaphragm external peripheral edge portion (6a) is at greater distance from an open end (7a) of the cylindrical body portion (7) with respect to an orthogonal plane (V) orthogonal to a central axis line (1a) of the device. The length dimension of the diaphragm plate (6) and the length dimension of the cylindrical body portion (7) in the axial direction can be increased. Therefore, the fatigue strength of the diaphragm plate (6) and the load capacity of the wave gear device (1) in which the flexible externally toothed gear (3) has been incorporated can be increased.