| 摘要 |
1,183,654. Change speed control. NISSAN JIDOSHA K.K. 7 Feb., 1968 [9 Feb., 1967; 14 Feb., 1967], No. 5999/68. Heading F2D. In an automatic control system for a planet change speed gear wherein line pressure 125 for operating ratio establishing clutches and brakes (4 ... 7) is controlled by a main pressure regulating valve 102 subject to throttle variable (TV) pressure modulation, the valve 102 is additionally loaded by TV pressure 140 supplied through a "cut-back" valve 200 to reduce line pressure when an output speed responsive governor pressure 130 acting on the "cut-back" valve 200 exceeds a predetermined value or a value responsive to TV pressure. As shown the governor pressure 130 acting on the " cutback " valve 200 opposes the bias of a spring 202 and when the governor pressure exceeds a predetermined value the spool 210 of the valve 200 moves left to supply TV pressure 131 through a line 146 to the regulator valve 102 which reduces line pressure. In Figs. 8 and 11 (not shown), the spool of the cut-back valve is biased right by a spring and TV pressure and when the governor pressure (130) exceeds both the spring and TV pressures the cut-back valve spool moves left to supply TV pressure to the regulator valve (102) which reduces line pressure. Fluid system components.-An engine driven pump (101) supplies pressure liquid to the regulator valve 102 which controls line pressure 125 and admission of regulated pressure to a torque converter (3). An engine manifold depression servo 142 controls a throttle valve 107 supplying TV pressure 131 to a TV boost valve 108, the cut-back valve 200 and a line pressure boost valve 103 which latter increases line pressure with increasing TV pressure. The land 312 of the boost valve 103 is larger than the land 301 of the regulator valve 102 so that when TV pressure acts on both lands, TV pressure modulation of the regulator valve 103 is retained. The TV boost valve 108 supplies boosted TV pressure 133 to 1-2 and 2-3 shift valves 105, 106. The valves 105, 106 are automatically shifted in response to opposing boosted TV pressure 133 and output speed responsive governor pressure 130 which latter is supplied by first and second governor valves (112, 113) rotating with the gear output shaft. A 2-3 timer valve 111 controls the rate of engagement of a direct drive clutch (4) and release of a second ratio brake (6) during a 2-3 upshift. A manual range selector valve 104 has Reverse (R), Neutral (N), Drive (D) and Low (L) positions. In the reverse (R) and Low (L) ranges pressure liquid is supplied through a line 128 to the regulator boost valve 103 to increase line pressure. In the low (L) range a 2-1 downshift is permitted but a 1-2 upshift is prevented by supplying additional loading pressure 135 to the 1-2 shift valve 105 in first ratio. A solenoid-operated "kickdown" valve 110 supplies additional downshift loading pressure 134 to both shift valves 105, 106 when the accelerator pedal is depressed beyond its normal range. |
