| 摘要 |
PURPOSE:To obtain a large transmission ratio with a small-sized and inexpensive apparatus by revolving a planetary wheel through engagement between a V- shaped concaved stripe formed on the inner peripheral surface of a fixed annular body and a V-shaped convex stripe formed on the outer periphery of the planetary wheel rotatably supported in the eccentric state in said annular body. CONSTITUTION:A plurality of engagement grooves 3 are formed in the circumferential direction on the inner peripheral surface of the peripheral wall 2a of a casing 2 while is constituted of an annular body 1 engaged onto a fixed member such as a motor case, and a frictional ring 4 having a plurality of engagement hooks 6 which are freely engaged into the above-described engagement groove 3 and protrude onto the outer peripheral surface is freely fitted into the casing 2. Said frictional ring 4 is constituted of divided pieces 4a-4c, and pressed or released by a clutch mechanism 7. A pair of eccentric roller bearings 14 are fixed in the state of phase diverged by 180 deg. each other onto an input shaft 13 rotatably supported in the casing 2, and a planetary wheel 15 having the outer periphery of a V-shaped convex stripe 16 is rotatably installed onto the roller bearing 14, and is inscribed onto a V-shaped concaved stripe 5 between divided pieces 4a-4c. |
