Wave gear device

Abstract

This invention provides a low-cost and lightweight undulating gear device by focusing on the materials used in the internal gear and housing, specifying the dimensions of the internal gear, and by appropriately selecting the materials and dimensions. The undulating gear device (1) includes an internal gear (2); a housing (11) for holding the internal gear (2); an external gear (3) having flexibility; and a undulating generator (4) for flexing the external gear (3) into a non-circular shape so that the meshing portion of the external gear (4) and the internal gear (2) moves circumferentially relative to the internal gear (2). The internal gear (2) is mounted on the housing (11) as a component different from the housing (11) and contains a resin with a glass transition temperature of 50°C or higher and a flexural elastic modulus of 2 GPa to 10 GPa. Furthermore, the maximum value W1 of the axial width of the internal gear (2) and the maximum value W2 of the radial thickness of the internal gear (2) satisfy the relationship 0.5≦W2 / W1≦2, and the housing (11) contains a material with a bending elastic coefficient of 5 GPa or higher.

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