Patent ID: 11959539
Assignee: RIKEN
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A strain wave gear device comprising:
an internal gear;
an external gear that has flexibility and is arranged at an inner circumference side of the internal gear; and
a wave generator that is assembled to an inner circumference of the external gear to cause the external gear to noncircularly deflect to form a meshing part with the internal gear in the external gear and to move the meshing part in a circumferential direction of the internal gear, wherein
the wave generator is configured such that the meshing part is formed at three or more positions in a circumferential direction of the external gear, and
in a state before the external gear is assembled to the wave generator, a value (DpF/ZF) obtained by dividing a working pitch diameter DpF of the external gear by the number of teeth ZF of the external gear is greater than a value (DpR/ZR) obtained by dividing a working pitch diameter DpR of the internal gear by the number of teeth ZR of the internal gear and, wherein
a tip diameter DaR, a root diameter DdR, and the number of teeth ZR of the internal gear;
a tip diameter DaF, a root diameter DdF, and the number of teeth ZF of the external gear; and
a lift amount D of a working pitch circle of the external gear, the lift amount D being generated by assembling the external gear to the wave generator, satisfy a relation of:

1<{ZR·(DaR+DdR+DaF+DdF−4D)}/{ZF·(DaR+DdR+DaF+DdF+4D)}≤1.11.