| 摘要 |
Deformation of bridge sections in an externally toothed gear and of outer teeth is suppressed, and this extends the life of tooth surfaces of external teeth (19), improves vibration characteristics, and drastically increases output torque while preventing a planetary gear device (11) from becoming large in size. To achieve the above, a ratio obtained by dividing the diameter (D) of pins constructing internal teeth (14) by the pitch (P) of the internal teeth (14) is made smaller to an extent where the tooth tops (19a) of the external teeth (19) are radially outside the inner periphery (15a) of an internally toothed gear (15), or alternatively, a meeting point (C) where the lines (S) of action of reaction forces (K) as drive force components meet is moved more radially outward than a conventional position so as to be positioned between a pin circle (P) passing the centers of all the internal teeth (pins) (14) and an outer end passing circle (G) passing radially outer ends of through-holes (22), or further alternatively, the amount (H) of eccentricity of an externally toothed gear (18) relative to an internally toothed gear is set not less than 0.5 times the radius (R) of the internal teeth (pins)(14). |
