Wave gear device

Abstract

This invention provides a wave gear device that achieves lightweight construction using resin materials while maintaining high durability and high torque. The wave gear device (1) includes: an internal gear (2); a ring-shaped external gear (3) disposed inside the internal gear (2) and having flexibility; a rotating support (6) disposed inside the external gear (3); and a non-circular cam (5) rotatable relative to the external gear (3) via the rotating support (6). At least one of the internal gear (2) and the external gear (3) is made of resin material, and at least the outer contact portion (6a) of the rotating support (6) that contacts the external gear (3) is made of a flexible metal material. The linear expansion coefficient A of the non-circular cam (5) and the linear expansion coefficient B of at least the outer contact portion (6a) of the rotating support (6) satisfy the relationship 0.4 < A / B < 4.0.

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