Patent GB-907695-A (GB)
Title: Change-speed transmission
Inventor: POLOMSKI JOHN B
IPC: F16H47/08
Filed: 1959-04-06
Abstract: 907,695. Change-speed gear and control. BORG-WARNER CORPORATION. April 6, 1959,No. 11600/59. Class 80 (2). To prevent slipping of fluid-pressure engaged reaction brakes in first speed, due to initial high torques, in a combined torque-converter and planet gear on a vehicle, two such brakes 17, 18 are applied in parallel one of which 18, augmenting 17, is released when a predetermined low vehicle speed is reached, say 5 or 10 m.p.h. by governor means comprising a shuttle valve 77 subject to the pressure of an output driven pump 81, the valve 77 also preventing application of the brake 18 when a clutch 21 is automatically engaged for second speed in which the first speed train is overrun by release of a oneway clutch 40 in series with the brake 17. Function summary.-The gear provides two reduced forward and one reverse ratio, torque converter driven, and an all-mechanical directdrive high. Drive setting D of an NDLR manual selector valve 82 selects the first speed, followed automatically by engagement of the second speed clutch 21 and finally a direct-drive disc clutch 20, under control of a shift-valve 83 operated mechanically by an output-driven centrifugal governor 218 loaded by the usual accelerator pedal 216. Pressure in the servo system but not in the torque converter is augmented in reverse. Output driven pump pressure inhibits engagement of reverse during forward motion. Gear arrangement.-The gear comprises two sun-ring trains 15, 16 in series behind a torque converter 14 of the overrun reactor type driven by an input shaft 10. In first speed the band brake 17 holds a front sun 30 and a rear sun 34 against reverse rotation through series, opposed one-way clutches 40, 39 respectively, for one-way low-low. The band brake 18, when applied in addition to 17, provides two-way lowlow, by directly holding the front sun 30 and holding the rear sun 34 against forward rotation through the one-way clutch 40. The torque converter 14 drives the front ring 29, and the front planet carrier drives the rear ring 33, the rear carrier driving a final output shaft 11, both trains reducing. For second speed, one-way direct-low, the front train 15 is locked by the disc clutch 21 and the brake 17 alone remains engaged to hold the rear sun. High speed is by engaging the mechanical drive disc clutch 20 directly connecting input and output shafts. The front train look-up clutch 21 may remain ineffectively on as may be the rear brake 17 which is overrun. Reverse, one-way negative low, is by applying a band brake 19 to the front carrier and connected rear ring 33 whereby the front sun 30 drives the rear sun 34 reversely through the one-way clutch 40, and the rear carrier, reacting on the stationary ring 33, drives the output 11 at reduced speed. Fluid supply system.-Input and output driven pumps 80, 81 supply a system pressure main 108 through one-way valves 110, 124 and relief valves 84, 85 respectively. Initially the input pump 80 supplies all the pressure, but when increased vehicle speed raises output pump pressure to a predetermined take-over value the regulating depression of the piston of the output pump relief valve 85 exhausts the delivery line from the input pump through ports 102, 103. Fluid system components include the NDLR selector valve 82; the automatic 1-2-3 shiftvalve 83; the shuttle valve 77; reverse inhibitor valve 79 releasing reverse pressure during forward drive; converter regulator valve 78. Operation.-In neutral setting N the selector valve 82 blanks the pressure main 108 which feeds the torque converter 14 through a line 199, the converter regulator valve 78 which regulates converter pressure to a value lower than regulated line pressure, and a torque converter supply line 178. From the converter oil passes out through a pressure maintaining spring- loaded valve 229 to lubricate the gearing. To stabilize the valve 85 the torque converter supply line is fed directly from the output pump 81 through a line 177, a restricted line 179, and a one-way valve 181 so that the pump 81 gradually takes over the torque converter supply prior to exhausting the delivery of the input pump 80. In drive D the selector valve 82 opens the pressure main 108 to lines 148, 145. The line 148 is blocked by the governor valve 83 in its low-speed position. The line 145 directly applies the brake 17 for first speed, and, through the shuttle valve 77 and line 176, the brake 18. At 5 or 10 m.p.h. the output pump pressure introduced through the line 177 is sufficient to shift a piston 162 of the valve 77 leftwards to block the inlet port from the line 145 and drain the line 176 through a line 144 and the selector valve 82. On further speed increase the governor valve 83 feeds a line 160 engaging the clutch 21 for second speed and, through a branch 184, the shuttle valve 77 to again block its inlet port from the line 145 and prevent the application of brake 18 when clutch 21 is engaged. On still further speed increase the governor valve 83, in addition to line 160, feeds a line 161 which engages the clutch 20 for direct drive. Low.-In L setting the selector valve 82 opens the pressure main 108 to line 145 which directly applies the brake 17 and, through the shuttle valve 77 and line 176, applies the brake 18. The line 144 is also fed from the line 145 through the selector valve 82 to feed the valve 77 to hold, with spring assistance, the piston 162 and thus maintain the application of brake 18 regardless of speed increase. Reverse.-In R setting the selector valve opens the pressure main 108 to a line 146 to engage the reverse brake 19 and to a line 147 which loads the input pump relief valve 84 (the output pump being inoperative in reverse), to increase the regulated oil pressure, and hence the brake pressure, for reverse, the same pressure 147 passing through lines 214, 213 to act on the converter regulator valve to maintain the torque converter pressure as for forward drive. To prevent engagement of reverse during forward movement of the vehicle, the output pump rotating in such circumstances feeds the reverse inhibitor valve 79 through a line 212 which valve then acts to drain the lines 147 and 214.