Patent GB-1274490-A (GB)
Title: Improvements in or relating to hydraulic gear-shifting devices
IPC: F16H47/08
Filed: 1969-07-10
Abstract: 1,274,490. Change-speed control. ZAHNRADFABRIK FRIEDRICHSHAFEN A.G. 10 July, 1969 [29 July, 1968], No. 34853/69. Heading F2D.  The working level of fluid servo pressure, for engaging ratio-establishing clutches K1, K2, and brakes B1, B1F, B2 in an automatic threespeed and reverse planet gear on a motor vehicle, is controlled by a main pressure-regulator valve 10, loaded by TV fluid pressure 48, 222c, responsive to engine load, charge pressure, or throttle opening, and shift is controlled by a manual ranging valve 30 having settings P, R, N, A, 2, 1, the A setting providing automatic shift between all three forward ratios under control of 1-2 and 2-3 shift-valves 70, 90, loaded rightwards for upshift by output-speed-responsive governor pressure 242, and leftwards for downshift by opposing TV pressure 220, 221, which is cancelled at engine idle, the rate of engagement of the clutches and brakes during shift being controlled by individual pressureregulator valves 110, 130, 150, 170, in their feedlines, and loaded by timing pistons 120, 140, 160, 170, some, e.g. 120, 160, of which are loaded by TV pressure so that engagement rate is TV responsive. The timing piston 140 of the first speed and reverse brake B2 is loaded by governor pressure 242 instead of TV when first speed is selected, so that its engagement rate is speedresponsive, but, when used for selecting reverse, governor pressure is replaced by line pressure in the timing piston and the brake engages without delay. Gear arrangement.-Various trains are shown diagrammatically in Figs. 11a-11f, not shown, all using two trains, some simple, some with intermeshed planets, but in all cases drive from a fluid coupling or torque converter is through selector clutches K1, K2 to different train elements, the clutch K1 being effective in all forward ratios, whilst K2 is used for third ratio (direct drive) and reverse. The brakes B1 and B2 provide reaction for second and first ratios respectively, the control embodiment described having a non-controllable one-way detent for first ratio; a controllable one-way brake B1F for reaction in one-way second ratio; together with a lock-up two-way brake B2 in manual 1 setting of the selector valve 30; and a two-way brake B1 for two-way second ratio in manual 2 setting. The brake B2 is also used for reverse. Fluid supply and regulation.-A single enginedriven pump P supplies the system main 205 through a pressure regulator valve 10, loaded by a spring and TV pressure 48, 222 derived from an engine throttle-loaded valve 40, described below. Spill from the regulator 10 feeds a hydrodynamic torque-converter W and cooler K. The regulator-valve 10 has two concentric loading springs, an outer 27a with fixed abutment, an inner 27b abutting a piston 21 which acts as a regulator valve for controlling pressure in the torque-converter W. Pressure augmentation in reverse ratio is provided by exhausting, through a manual ranging valve 30, described below, a line 207, which, in the forward settings of the manual valve, feeds line pressure to a load-opposing space at the left end of the regulator valve 10. Control pressures. (1) Governor.-Output-speed responsive pressure 240 is provided by a governor R, not described, fed with main pressure 205 208 in the forward settings only of the manual valve 30. (2) TV pressure 48, 222 is provided by a TV valve 40 loaded through a spring 43 by a piston 42, moved rightwards by increasing engine load, charge-pressure or throttle opening. TV pressure for loading the main regulator 10 and shifttiming pistons is taken directly from this TV line 48, 222, but TV pressure for loading the automatic 1-2 and 2-3 shift-valves 70, 90 is desired from two lines 220, 221 both of which exhaust at 42c in the engine-idle position of the throttle, so that TV pressure has no ratio-shift effect at that time. As the throttle is opened, the lines 220, 221 are supplied in sequence with TV pressure 48 through a groove 42a in the throttle-actuated piston 42, with the effect described below. Shift valves. (1) Manual.-The manual ranging valve 30 has settings P, R, N, A, 2, 1. In the automatic setting A, the valve 30 feeds main pressure 205 through a line 208 to the automatic shift-valves 70, 90 and through a branch 208a to the first clutch K1, which is always engaged in all forward ratios. Brake reaction in first ratio is taken by a one-way detent, so that initially, with both automatic shift-valves downshifted, first ratio is made effective. The subsequent upshift to second, which may also be one-way, is by the 1-2 shift valve 70, and to two-way third by the 2-3 shift valve 90. In manual settings 2 and 1 both second and first ratios are two-way, by engaging brakes B1, B2 respectively. In 2 setting, the manual valve 30 supplies a line 209, which, in the downshifted (left) setting of the 1-2 valve 70 pressurizes a line 212 engaging the first-ratio lock-up brake B2, and in the upshifted setting of the valve 70 supplies, through a line 213, and 2-3 shift valve 90, a line 216 engaging the second-ratio lock-up brake B1. In reverse setting R, the manual valve 30 supplies at 36 the brake B2 and the clutch K2, through lines 211a, and 210, 2-3 shift-valve 90, and 215 respectively, and blanks off the feed line 208 to the governor R and automatic shift-valves. (2) Shift-valves automatic.-The 1-2 and 2-3 valves 70, 90 each comprise two separate differentially-landed spools 71, 76 and 91, 98. In their leftward, downshifted, position, shown, the valves exhaust respectively the feed line 214 of the second ratio one-way brake B1F, and 215 of the third ratio clutch K2, whilst on upshift to the right they supply line pressure 208 (in the A setting of the manual valve 30) to these lines 214, 215. Differential lands, e.g. 76a, 76b on each side of the brake and clutch line feed spaces 78, 100, provide rightward loading on the shift-valves on upshift, giving snap action and a first or normal up-down hysteresis. The shift-valves 70, 90 are upshifted to the right by governor pressure 240 opposed by springs and by TV pressure in the lines 220, 221 acting in stages as follows. At engine idle, both lines 220, 221 are exhausted at 42c and there is only spring opposition to governor pressure 240 in the shift-valves 70, 90. When the enginethrottle is opened sufficiently to pressurize the line 220 through the groove 42a, TV pressure therein passes through non-return valves 220a, 220c, to the right end of both shift-valves 70, 90 and to a space 94 between differential lands at the left end of the 2-3 valve 90, providing leftward loading in all cases to raise the upshift-speed. When the 2-3 valve 90 upshifts right, the space 94 is shut off from TV 220 and exhausted through the port 96, non-return valve 221a, line 221 and TV exhaust 42c, thus reducing downshift speed in comparison with that of upshift, and providing extra hysteresis additional to the normal hysteresis referred to above. With increased throttle opening, the line 221 receives TV pressure as well as 220, which passes through a non-return valve 221c to a space 74 between differential lands of the 1-2 valve 70, providing additional opposition to upshift in that valve also. Manual downshift; blocking-valve action.- When the manual ranging valve 30 is in setting 2, an additional passage 230 supplies line pressure to a blocking valve 50, which is a spring- loaded regulator valve supplying a constant reduced pressure to a line 231. If this reduced pressure is greater than the prevailing TV pressure it shuts the non-return valves 220c, 221a, and acts in the space 94 of the 2-3 shift-valve 90 to downshift that valve. Similarly in manual valve setting 1, a second blocking valve 60, fed through a passage 235, provides pressure 236 to close the non-return valves 220a, 221c and replace TV pressure in the 1-2 valve, thus downshifting that valve. Timer valve action.-The rate of engagement of the clutches and brakes is controlled by the pressure-regulator valves 110, 130, 150, 170, the first of which is as follows: When pressure to engage the clutch K2 is fed to the line 215 through the upshifted 2-3 valve 90, the pressure immediately passes through the regulator valve 110 and passages 126b, 126, for rapid filling of the clutch. As clutch pressure builds up it acts through a restrictor 126a on the left face of the regulator valve 110, shifting the latter rightwards to restrict further increase in clutch pressure. The regulator valve 110 is loaded leftwards, to oppose this restriction, by a loading spring 122 butting on a timing piston 121. Clutch pressure acting leftwards on the piston 121 is opposed by TV pressure 222, 222a, applied to the spring chamber 123, so that the piston moves leftwards, increasing the loading on the regulator valve 110, so that clutch pressure is proportional to the sum of TV pressure 222 plus the instantaneous compression of the spring, until the timing piston 124 reaches an abutment collar 116 on the regulator valve 110, whereafter the valve is positively opened for rapid final clutch engagement. When the line 215 is exhausted for downshift by the 2-3 valve 90, the clutch K2 and the pressure space at the right of the timing piston 121 both exhaust rapidly to the line 215, directly and through a non-return valve 127a respectively. The regulator valve 130 serving the brake B2 has a different action according to whether it is used to provide third ratio forward or reverse. Action for forward is identical to that of the regulator valve 110 above described, with the exception that the spring chamber 143 is supplied with governor pressure 242 instead of TV, so that the rate of brake-pressure increase now increases with speed. In reverse pressurizing of passage 211a through the manual valve 30 changes over two non-return valves 212a, 245, the former supplying pressure to the regulator valve 130, the latter shutting off governor pressure 242 and sup