| 摘要 |
PROBLEM TO BE SOLVED: To provide a planetary gear device having sufficient performance and durability without giving surface hardening heat treatment to an external gear. SOLUTION: The inscribed meshing type planetary gear device is provided for transmitting revolving motion with the rotation of the external gear in an internal gear via a crank shaft to a carrier. When the curvature of the circular profile of the internal teeth is -1/r and the curvature of the tooth profile curve of the trochoid profile of external teeth is 1/ρ, the external teeth are a theoretical trochoid tooth profile curve where an overall curvature 1/R of a contact surface between both internal and external teeth is expressed by 1/R=-1/r+1/ρ=(-ρ+r)/(r×ρ). The external teeth each have a contact portion which contacts the internal teeth of the internal gear and contributes to torque transmission and an addendum portion which is corrected to form a tooth face inward from the theoretical tooth profile curve and does not contribute to torque transmission. An absolute value for the overall curvature of the contact portions of the external teeth at positions of meshing with the internal teeth is set to be a predetermined value or lower so that the number of the external teeth meshing with the internal gear is the number of the external teeth being 2-8% of the total external teeth located on the side of meshing eccentrically from the internal gear. COPYRIGHT: (C)2007,JPO&INPIT
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