Abstract: A wave generator for a strain wave gearing makes a flexible externally toothed gear to flex into an elliptical shape and mesh with rigid internally toothed gears, and makes meshing positions of the flexible externally toothed gear with the both gears to move in a circumferential direction. On the inner side of a rigid plug of the wave generator, a plug support ring is secured and integrated. The rigid plug is formed from an iron-based material, and the plug support ring is formed from a high-rigidity material that is more rigid than the iron-based material. Since deformation of the rigid plug is suppressed, the wave generator provided with a large hollow part can be obtained.

Abstract: A wave generator for a strain wave gearing makes a flexible externally toothed gear to flex into an elliptical shape and mesh with rigid internally toothed gears, and makes meshing positions of the flexible externally toothed gear with the both gears to move in a circumferential direction. On the inner side of a rigid plug of the wave generator, a plug support ring is secured and integrated. The rigid plug is formed from an iron-based material, and the plug support ring is formed from a high-rigidity material that is more rigid than the iron-based material. Since deformation of the rigid plug is suppressed, the wave generator provided with a large hollow part can be obtained.

Abstract: A rigid internal gear of a wave gear drive is comprise by a tooth-formed member having inner teeth and a circular gear body member, these two members being integrally connected with each other. The tooth-formed member is made of ferrous or copper material having a high strength and wear resistance, while the gear body member is made of lightweight material such as aluminum alloy and the like. These members are connected integrally with each other in a manner that one of these members is formed with baffle means and the other member is made by enveloped casting, or that the member having baffle means is pressed into the other member. These members are therefore surely connected with each other, so that a high torque can be transferred between these members. Also, the lightweight of the rigid internal gear can be achieved without deteriorating strength, wear resistance or the like thereof.