GB839844A - Variable speed friction drive - Google Patents

Abstract

839,844. Variable-speed gear. WEBER, M. May 10, 1956 [May 12, 1955; Oct. 18, 1955], No. 14632/56. Classes 80 (1) and 80 (2). A continuously variable-ratio gear comprises a set of planetary rollers 19, Fig. 1, engaged by a coned driving roller 21 formed with two sets 22, 23 of oval sockets receiving projections 20 on one of two coned surfaces of the rollers 19, and a non-rotary torqueresponsive coned thrust member 2 having a lining 3 also provided with suitable recesses for the projections 20. Alternatively, the projections may be located upon the driving roller 21 and the thrust member 2, the sockets being formed in the planetary rollers 19, Fig. 4 (not shown). The ovality of the recesses 22, 23 allows slight axial displacement of the rollers 19 so that they may be frictionally engaged with a ring 18 on a drum 17, splined for axial movement on a driven shaft 15 under the control of a hand lever 26. The torque-responsive axial movement of the coned thrust member 2 is produced by roller-and-inclined-race means 4-7. In a modification, Fig. 2 (not shown), the torqueresponsive roller means 4-7 are replaced by a torque-responsive threaded means. In another modified form, the gear comprises a driving cone 41, Fig. 5, and planetary rollers 43 having two coned portions with their apices directed away from each other. Projections and sockets are provided on the engaging faces, as described above. One coned portion of each roller engages a non-rotary coned thrust member 50 pressed against the rollers by a spring 55, a resilient washer 51 and torque-responsive ball- and-inclined-race means 53, while the other coned portion engages an internal ring 56 axially movable in a driven drum 60 to change the ratio. In the Fig. 5 form, there are two driving cones 41, each fast with a bevel sungear 40 meshed by bevel planet pinions 39 carried by an input shaft 34. The two driving cones 41 engage two sets of planetary rollers 43 in turn engaging two deformable rings 56 in the driven drum 60. The planetary rollers 43 of each set are connected by a freely floating cage 46. The hub of the drum 60 is toothed to engage a gear 79 rotating a gear 78 meshing a gear 80 fast on a driven shaft 83. A cylinder 62 rotatably surrounds the drum 60 and is provided with oblique slots 61 receiving projections 58 on blocks 57 carrying the two rings 56, the blocks 57 sliding in axial slots in the drum. Turning the cylinder 62 relative to the drum 60 thus slides the rings 56 towards or away from each other to vary the velocity ratio. Control is effected hydraulically, a gear pump 69 supplying oil under pressure through a valve 68, operated from a hand lever 74 in a stationary casing 35, 75 to conduits 66, 67 connected to opposite sides of an annular groove 64, Fig. 6, in which lie " pistons " or projections 63 fast with the cylinder 62.