GB655487A - Improvements in or relating to automatic variable speed transmissions - Google Patents

Abstract

655,487. Variable speed gear. CLEVELAND, F. J. (Windfields (1946), Ltd.), and WINDFIELDS (1946, Ltd. May 31, 1948, No. 14621. Addition to 639,675. [Class 80(ii)] An automatic variable speed transmission comprises a fluid torque converter having first and second speed runners driving gearing connected with an output shaft and a reaction member held against backward rotation by an overrunning clutch, and clutch means controlled by a speed and torque sensitive governor for interconnecting the converter input member with the geartrain reaction member for providing high speed or direct drive. As shown, an input shaft 1 drives the impeller 2 of a torque converter A, the first and second stage stage runners 3, 4, of which drive. through hollow shafts 11, 15, two sun gears 16, 17, which, meshing with stepped planet gears 24, 25 drive a shaft 28 through gears 26, 27. A torque spider 45 splined to the shaft 28 has arms 46 engaging fulcrum blocks 44 in weights 41 pivoted on pins 42 in a drum 40 secured to a transmission shaft 8 and so arranged that the gear drive opposes the centrifugal force of the weights. Attached to one weight 41 is a link 52 actuating a fluid controlling piston valve 51 in a bore 50 of the shaft 8. The planet carrier 20 carries a normally disengaged hydraulically actuated friction clutch comprising discs 29, 30 secured to the carrier 20 and converter housing 5, and engagement is effected by an axially moving piston 33 to which fluid pressure is applied via a passage 54. In operation, first and second gear drives are respectively from the runners 3 or 4, through the planetary gearing and governor to the tail shaft 10, via reversing gearing, the weights being withdrawn and a clutch 12 overrunning in second gear. On speed increase or torque reduction in the latter gear, the centrifugal force of the weights 41 overcomes the torque reaction thereby moving valve 51 to permit fluid flow through conduits 53, 54 and engaging the clutch yielding direct drive from the casing 5. Returning to second gear for acceleration is effected by kick-down of the .accelerator pedal which, by a cable 58 actuates an auxiliary valve 57 to interrupt the fluid supply and disengage the clutch. A band brake 80 actuated simultaneously with the valve 57 permits engine braking.