Patent GB-1191388-A (GB)
Title: Automatic Control Valve System for a Multiple Ratio Power Transmission Mechanism.
IPC: F16H61/10
Filed: 1968-05-08
Abstract: 1,191,388. Change-speed control. FORD MOTOR CO. Ltd. 8 May, 1968 [9 May, 1967], No. 21773/68. Heading F2D. In a vehicle change-speed planetary gear giving three forward gears and reverse which are selectively engaged by hydraulically-actuated brakes 68, 106 and clutches 40, 120 controlled by automatic shift valves 186, 206 which respectively control 1-2 and 2-3 gear shifts in accordance with opposing signal pressures responsive to vehicle speed (sensed by a governor 122) and engine inlet manifold depression and a manually operable ranging valve 156 controlling servo-pressure distribution from a main regulator valve 130 to the shift valves, coasting 2-1 downshifts on moving the manual valve 156 to its "1" position from either of its "2" or "D" positions is inhibited above a safe vehicle speed by an inhibitor valve 258. The valve is loaded down by governor pressure 124 against a spring 274 and a constant controlled pressure 334 from a 2-1 scheduling valve 316 via a line 314 and a three-way valve 332, and prevents control pressure 268 from the 1-2 shift valve 186 from being applied to the rear brake servo 106 through a lock out valve 284. The scheduling valve 316 ensures that the 2-1 downshift always occurs at the same shift point. On a coasting 2-1 downshift occurring, the inhibitor valve is shifted up to connect control pressure 268 to the rear servo 106 apply line 256 which also shifts a transition valve 240 up against forward clutch apply pressure 54 to allow the intermediate brake servo apply line 250 to drain. Control pressure in line 256 is also supplied to line 334 via valve 332 to hold the inhibitor valve up against governor pressure 124. Function summary.-The manual ranging valve 156 has six settings; park; reverse; neutral; drive D allowing one-way first start with automatic shifts between the forward gears; "2" in which the gear is held in second; and "1" in which the gear is held in two-way first. 3-2 and 2-1 accelerator kick downshifts are provided below predetermined speeds in the "D" range, by a downshift valve 298 and a 3-2 kickdown control valve. Gear arrangement. Fig. 1 (not shown).-The engine drives the gear input shaft (36) through a torque converter 18. The shaft (36) is fast with the driving elements of the clutches 40, 120 which drive sun gears (92), (84) respectively meshing planets wheels (90), (88) which intermesh, the wheels being mounted on a common carrier (82), and the gear output shaft (96) being fast with a ring gear (94) meshing planet wheels (88). For two-way first, the common carrier is held by rear brake 106 and the sun (92) is connected to the input shaft (36) by clutch (40). For one-way first, with clutch (40) engaged, reverse rotation of the carrier is prevented by a one-way detent (116). For second, the clutch (40) remains engaged, and sun gear (84) is held by brake 68. For direct drive third, both clutches (40) and (120) are engaged to lock up the gear train. For reverse, clutch (120) is engaged, and the carrier held by brake 106. Brakes and clutches.-Clutches (40), (120) are multiplate friction clutches applied by hydraulically actuated pistons acting, for clutch (40), through a Belleville spring. Brakes 68, 106 are servo applied band brakes. The servo for brake 68 having both apply and release chambers. Fluid pressure supply and regulation.- Pressure is supplied by a first pump 34 driven by the input shaft and by an output driven rear pump 98 and is supplied through check valves to a main line 136 at a pressure regulated by a valve 130 which has a spool biased downwardly by a spring 146 against main line pressure 136 acting on differential lands on the spool, and compensator pressure 354 from a valve 350 acted on by governor pressure in line 352 and T.V. (torque variable) pressure in line 356 from a vacuum throttle valve 336. Operation.-"1" setting of the manual valve 156 admits pressure to lines 174, 172 and 168. Line pressure 168 engages the front clutch 40 and moves the rear servo lock out valve 284 down. Line pressure 174 communicates through threeway valve 180 with line 182 which charges line 256 through the 1-2 shift valve 186, line 202, and the inhibitor valve 258. Line pressure 256 then applies the rear brake servo 106 via line 254, the rear servo lock out valve 284, and line 114. Pressure in line 256 also forces the transition valve 240 up to drain the intermediate servo apply line 250, and pressurizes line 334 to hold the inhibitor valve up against governor pressure. Line pressure 172 from the manual valve 156 holds the 1-2 shift valve downshifted, and communicates with a 1-2 shift accumulator valve. "2" setting of the manual valve 156 admits pressure to lines 168, 172. The line pressure 172 holds the 1-2 shift valve downshifted. Line 182 is drained and drains lines 256, 254 to allow the transition valve to move down to connect the intermediate servo apply line 250 to front clutch apply pressure 168. The 2-3 shift valve has no influence on the speed ratio selected. "D" setting of the manual valve 156 admits pressure to lines 168, 170. The rear servo lock out valve 284 is moved up to control pressure in line 184 and a start is made in one-way first. Automatic 1-2 and 2-3 shifts are then controlled by the shift valves acting under the opposing influences of governor pressure 124 and modulated T.V. pressure 200 from a throttle boost-valve 358 via a reducing valve 206. "R" setting of the manual valve 156 admits pressure to line 176 which applies the rear clutch 120 through the 2-3 shift valve. Clutch apply pressure also acts on differential lands on the rear servo lock out valve 284 so that when the clutch apply pressure is sufficient to maintain clutch capacity, the valve moves down to apply the rear brake servo 106. Servo apply pressure is fed to the valve 284 in line 254 from line 174 via line 182, the 1-2 shift valve, line 202 inhibitor valve 258, and line 256, the 1-2 shift valve being held downshifted by line pressure 172.