Method for manufacturing strain wave gear

A method for manufacturing a strain wave gear comprising:

• a ring-shaped internal gear (110) having gear teeth (115) on the inner periphery thereof and a plurality of through holes (113) in a circumferential direction thereof in such a way as to pass therethrough in an axial direction thereof;
• an external gear (120) having gear teeth (123) engaging with the gear teeth (115) of the internal gear (110);
• a camshaft (140) located inside the external gear (120) and having a wave generation portion (143) on the outer periphery thereof;
• and a bearing (130) located between the external gear (120) and the camshaft (140),
• wherein the external gear (120) comprises a cylindrical portion (121) having the gear teeth (123) on the outer periphery thereof in such a way as to engage with the gear teeth (115) of the internal gear (110), a bottom (125) on the end portion of the cylindrical portion (121), and a protruding portion (127) protruding from the bottom (125) in an axial direction thereof,
• the method comprising the step of manufacturing one or more of the internal gear (110), the external gear (120), and the camshaft (140) by means of sintering.