| 摘要 |
979,062. Variable - speed friction gear. NATIONAL RESEARCH DEVELOPMENT CORPORATION. May 18, 1961 [May 18, 1960], No. 17606/60, Heading F2D. Variable-speed friction gearing of the toric disc and precessional roller type is provided with means for equalizing the load between the rollers. As shown diagrammatically in Fig. 1 each roller 22 is rotatably mounted in a carrier 21 universally jointed at 18 to a cranked rocker 4 which is pivoted at 1 on a fixed reaction plate (not shown) and the free end of which engages a recess 10 in a common control member 13 which is rotatable to tilt all the carriers equally but which floats radially and is shifted radially by an overloaded roller to move this roller to a lower ratio position and the other rollers to higher ratio positions. The free ends 24 of the roller carriers 21 ride in sockets 25 anchored to the reaction plate. In a modification the ends 24 of the roller carriers are carried by rockers engaging a second radially floating control member which is used during reverse rotation of the transmission, the control member 13 being free from rotational restraint during reverse rotation. The precession of the rollers may be terminated by a screwing action, the universal joint 18 being formed by a ball disposed in a socket provided in the rocker and the roller carrier having a screw connection with the ball, alternatively the axis about which the roller carrier pivots may be at an angle to the plane of the torus centre circle. In the embodiment of Fig. 6 a roller carrier 440 has a screw connection with a pin 443 pivoted to a rocker 446 which has a ball-ended arm 450 engaging a notch 451 in a common radially floating non-rotatable member 452 which equalizes the load between the rollers. Tilting of the carriers 440 to vary the ratio is effected by angular adjustment of a common control ring 455 having notches 454 engaged by semi-circular webs 453 formed on the carriers. The invention may also be applied to a transmission of the type having two sets of rollers co-operating with two driving discs and a central driven disc having a toroidal track on each side. U.S.A. Specification 2,140,012 is referred to. |
