GB954504A - Fluid-mechanical power transmission unit - Google Patents

Abstract

954,504. Hydro-mechanical variable-speed gear. M. M. SURI. Sept. 15, 1960, No. 31802/60. Addition to 851,515. Headings F2C and F2D. Variable-speed gearing for Diesel trains &c. comprises an engine-powered shaft 1 which on starting drives through gears 2, 3 to the impeller 4a of an hydrodynamic torque converter whose turbine 4b drives through gears 7, 8 to an output shaft 6, establishment of direct mechanical torque transmission through the gearing being effected by emptying the torque converter while simultaneously filling a small fluid coupling 14, 15 to synchronize a clutch 16, which can then be engaged by admitting oil under pressure through a shaftduct 19, 19a to a servo cylinder 19b. The clutch 16 can be disengaged by admitting oil under pressure through a shaft-duct 20, 20a to an oppositely disposed servo cylinder. As shown, the clutch 16 is of the multi-disc type, and input and output driven pumps 21, 22 supply oil through a differential valve 27 to lubricate the gear bearings, and also the plates of the clutch 16 when the latter is disengaged. Control is effected from a manually-operated lever which in a first position admits compressed air to a valve 23, thereby conditioned to pass oil from the engine-driven pump 21 and a pipe 21a through a pipe 23a and a valve 24 connected to a pipe 24a to fill the torque converter 4. When a sufficiently high speed of the train has been reached, the manuallyoperated lever is moved to a second position in which the valve 24 is moved by compressed air to drain the torque converter 4 and instead connect the pressure oil supply pipe 23a to a pipe 24b leading to the fluid coupling 5, accordingly filled for synchronization. The manuallyoperated lever is then moved to a third position, so that compressed air conditions a valve 25 to pass oil from the output-driven pump 22 and a pipe 26a to a pipe 26b and the shaft-duct 19 for engagement of the multi-disc clutch 16. Oil under relatively low pressure is supplied continuously from whichever of the input and output driven pumps 21, 22 produces the greater pressure through throttling devices 28, 29 and the differential valve 27 to the shaftduct 20 for clutch disengagement, which is effected by restoring the valve 25 to the position shown and accordingly venting the clutchengaging pipes &c. 26b. The pressure of the oil produced by the output-driven pump 22 may be used to actuate electromagnetic relays preventing engagement of the clutch 16 below a predetermined speed, or restoring the gearing to neutral above a predetermined speed, these relays acting on the valves 25 &c. Further, the relays may actuate the brakes of the train.