Patent GB-1074269-A (GB)
Title: Automacic transmission for a motor vehicle
IPC: F16H47/08
Filed: 1965-09-30
Abstract: 1,074,269. Change-speed control. FORD MOTOR CO. Ltd. Sept. 30, 1965 [Oct. §, 1964] No. 41486/65. Heading F2D. An automatic transmission comprising an hydraulic torque converter followed by epicyclic gearing providing three forward ratios and reverse is controlled by an hydraulic control system having a manual valve 172 (Fig. 2B, not shown) settable to two drive ranges, namely a drive D1 position in which all three forward ratios are available, and a drive D2 position in which intermediate (second) and high (third) ratios only are available. Shift from first to second ratio is controlled by a one-two shift valve (Fig. 2A, not shown) having two spools, a valve spool 204 biased by a spring 224 to its uppermost, first ratio, position and a spool 206 subject to output speed-responsive pressure 234 opposed, when the engine throttle is open beyond a predetermined position, by pressure responsive to the engine intake manifold depression (TV pressure). In the D2 position of the manual valve 172 main line pressure is supplied to a space between the spools 204, 206 to shift the spool 204 downwardly to its second ratio position irrespective of the vehicle speed and throttle opening. Gearing.-The vehicle engine drives an impeller 18 of a torque converter having an overrunning reactor 22 and a turbine 20 fast with the common input member 34 of a forward clutch 36 and of a direct and reverse clutch 38. The driven part of clutch 36 is fast with a ring gear 40 of a front train having a carrier 70 fast with an output shaft 72 and a sun 46 common to the rear train and fast with the output member 44 of the clutch 38. The member 44 can be stationed by a brake 50. The rear train has an output connected ring gear 74 and a carrier 80 held one-way by a brake 96 and stationed by a brake 82. First gear is established by engaging clutch 36, the carrier 80 being held by the one-way brake 96. For continuous operation in first ratio brake 82 is applied, the control system being conditioned to inhibit upshift. Second gear is established with clutch 36 and brake 50 applied to station the sun 46. Third gear (direct drive) is established by releasing brake 50 and engaging clutches 36, 38 to lock-up the front train. Reverse is established by engaging clutch 38 and applying brake 82. The clutches and brakes are engaged by fluid pressure servos. Control system.-Pressure is supplied by an engine-driven pump 24 to a main regulating valve 104 which regulates the pressure supplied to a main line 164 for the clutch and brake servos. The valve 104 also supplies a line 132 leading to the torque converter and to the transmission lubricating system. The valve 104 is loaded by fluid pressure to increase the main line 164 pressure during reverse drive and during coasting and at high vehicle speeds, and at other times is loaded by TV pressure to increase line 164 pressure when accelerating. The manual valve 172 has reverse R, neutral N, first drive range D1, second drive range D2 and low drive range L positions and controls supply to the one-two shift valve 204, 206 and to a two-three shift valve 236. Both shift valves are biased towards their upshift positions by output speed responsive governor pressure 234 opposed by modulated TV pressure 222; and in their downshift positions only both valves are biased in the downshift direction by main line 164 pressure acting on differential lands, the removal of this pressure in upshifting preventing hunting. The governor valve assembly comprises primary and secondary valve elements 330, 342, the primary element 330 being shifted at a predetermined speed and thus relieving fluid pressure loading on the secondary element 342 which begins to produce the governor pressure 234. The TV pressure is derived from the main line 164 pressure by a primary throttle valve 260 loaded by a suction servo connected to the engine intake manifold. The TV 272 pressure is augmented by a booster valve 294 at advanced engine throttle settings, and modulated by a valve 256. Kick-down shift is provided by a valve 308 connected to the accelerator pedal by a lost-motion linkage and actuated on full pedal depression, valve 308 supplying augmented TV pressure to the twothree and one-two shift valves to bias them in the downshift direction. Up- or down-shift to second ratio is cushioned by an accumulator valve 388 which establishes a back pressure on the release side of the double-acting servo 54 of the intermediate brake 50 during these shifts and increases the cushioning for threetwo downshift at low vehicle speeds with the engine throttle open.