GB630961A - Improvements in or relating to variable speed transmissions - Google Patents

Abstract

630,961. Hydraulic clutches. BORGWARNER CORPORATION. March 5, 1946, No. 6778. Convention date, July 9, 1942. [Class 69 (ii)] [Also in Group XXIV] In friction clutches in parallel with speedchanging means between a driving and a driven shaft, the effect of drag between the clutch members, when the clutch is disengaged and the speed-changing means is operative, is eliminated by freeing one clutch member from its shaft by releasable connecting means which are either fluid pressure controlled or conditioned for a drive therethrough by means responsive to driving or driven shaft speed. As shown applied to hydromechanical variablespeed gearing of the kind described in Specification 624,858, in which a hydraulic torque converter 12, Fig. 1, is followed by an epicyclic gear 13 and both have direct drive friction clutches 36, 57 respectively across them, the clutch 36 operates in the converter fluid space and comprises a single driven plate 35, engaged between a back plate 18 and a combined piston and presser plate 30 when pressure fluid is supplied to the latter via conduits 28, 27. The plate 35 is connectible to its shaft 15 by a one-way clutch comprising rollers 39 mounted in a cage 42 which is rotatable by spring- restrained centrifugal weights 44, acting through forked arms 45 and pins 46, to a jamming position. Below a predetermined speed of the shaft 15, when the clutch 36 is disengaged and the converter 12 operative, the plate 35 is free on its shaft 15 to rotate under the fluid drag of the member 30. Above this speed the clutch 39 is brought into operation and the clutch 36 is thereafter engaged for a direct drive across the converter. In a non-speedresponsive modification, Fig. 4, the roller clutch is replaced by radially sliding ratchet pawls 69 forced outwards against spring action by fluid pressure, supplied via conduits 74, 73 to engage co-acting ratchet teeth on the hub 65 of the plate 35. The pawls are mounted in a member 63 supporting the plate 35 and connected to the shaft 15 by circumferentially acting springs 64.