Patent GB-1340563-A (GB)
Title: Gears
IPC: F16H15/38
Filed: 1971-01-07
Abstract: 1340563 Continuously-variable friction gear G TITT 7 Jan 1971 851/71 Heading F2D A continuously variable-speed friction gear for motor-vehicles comprises barrel-shaped idler rollers 2 bearing against opposed faces of driving and driven discs 1, 3 and carried on radial spindles 22 tilted about spherical bearing pivots 7, 12 carried in a cage 5 and shell 11 respectively relatively axially movable by a manually operated oppositely handed i.e. left and right hand screw-threaded sleeve 15, whereby the idler rollers 2 are tilted to vary their areas of relative contact on the discs 1, 3 for infinitely variable ratio change, camming rollers 20, arranged between cam profiled plates 18, 19 (Fig. 3) exerting a torque responsive thrust to axially load the friction rollers and plates in accordance with the transmitted torque, the cam plate 19 acting through pivoted levers 26 to magnify the axial compressive load on the driving disc 1, axially slidably keyed on an input shaft 4, the driven disc 3 being axially supported against a thrust bearing 6 and connected to the final output shaft 32. The screwed sleeve 15 may be manually turned by a hand wheel which via a carden shaft 27, 28 turns a pinion 43 meshing a gear-wheel 42 fast on the sleeve 15, the carden shaft additionally, via meshing gears 44, 45, turning an indicator 46 indicating the speed ratio setting on a dial 47, Fig. 4 (not shown) illustrates an alternative method of turning the sleeve 15 by a hand wheel directly via a carden shaft (27, 28) rotating a left and right handed screwed rod (17) to relatively turn the screwed sleeve 15, and the ring 13 connected by spacer bolts 14 with ring 11 (Fig. 6, not shown). In Fig. 5 (not shown) the balls of the thrust bearing 6 are carried in a cage and form a second friction gear, the cage being connected to a sun (30) of a stepped planetary gear the ring (31) of which is connected to the driven friction disc 3 and the stepped planet carrier of which is connected to the output shaft 32, the arrangement providing a split torque friction input and a split torque positive output. In Fig. 7 (not shown) the main friction gear with the barrelled roller idlers 1, 2, 3 is combined with a sun-ring planetary two-speed gear 32- 37 providing a fixed low drive, by a one-way detent (36), and direct drive, the fixed low ratio reduction working up to 1 : 1 direct drive through the friction gear 1-3 to the 1 : 1 direct drive at which time the planetary unit is locked solid by the planetary gear acting as a pump controlled by a centrifugally operated valve (not shown) for direct solid drive, the arrangement in this embodiment providing a split torque positive output C.S.G. with the friction gear accelerating the ring gear 35 from zero to the 1 : 1 speed. An enforced fixed ratio low may be effected by the application of a brake 38 which overrides the friction gear. Automatic control of the friction gear may be effected by centrifugally operated levers (39) normally held inwardly by springs (41) and connected via left and right handed screwed rods (40) to tilt the spindles of the barrelled rollers when the levers (39) are centrifugally outwardly moved with increasing speed of the vehicle.