Internally meshing planetary gear structure, reduction or step-up gear having said structure, and method for machining said reduction or step-up gear

摘要

The eccentric body shaft bearing holes (110a, 110b), the eccentric body bearing holes (119a, 119b) and the carrier pin holding holes (151, 152) are set to satisfy the following relationship. Namely, when the first and second supporting blocks (104, 105) and the externally toothed gears (118a, 118b) are appropriately rearranged in the axial positions thereof, the diameters (D1, D2) of the eccentric body shaft bearing holes and the diameters (D3, D4) of the eccentric body bearing holes become smaller toward one direction. Also, while keeping the above rearrangement, the diameters (D5, D6) of the carrier pin holding holes (151, 152) become smaller in the same direction. The outside diameter (D12) of the first and second supporting blocks is set to be smaller than the root diameter (D11) of the external teeth of each externally toothed gear. Further, the teeth number of each externally toothed gear is set to be the integral magnification of the number thereof, and the teeth number difference between the internal gear and the externally toothed gear is set to be the integral magnification of the number of the externally toothed gears. With this construction, it is possible to simultaneously machine the bearing holes and the externally toothed gears with one setting, and hence to improve the relative positional accuracy of each hole.