| 摘要 |
PURPOSE:To reduce the load applied to a hydraulic pump, by controlling line oil pressure in the above described device for a subspeed change gear in an automobile to low pressure when not fed to a hydraulic actuator and increasing it with a pressure regulating valve when fed to the actuator. CONSTITUTION:When an output power shaft is being rotated, pressure oil is led from a hydraulic pump 47 to a pressure-regulating valve 60 through an oil line 58 and pressure regulated, then the line oil pressure is produced at a port 70 and fed to a selector valve 73. When a solenoid 81 is not in conduction of an electric current, this oil pressure is relieved through an oil line 88, pilot pressure chamber 78, oil line 79 and port 83 not to produce oil pressure in the pilot pressure chamber 78. Accordingly the oil pressure to a cylinder chamber 41 in a subspeed change gear is disconnected. However, if the solenoid 81 is conducted to flow an electric current, oil pressure at not less than a prescribed level is generated in the pressure chamber 78 of the selector valve 73 to cause the shifting motion of a spool valve 76, then the oil lines are linked to lead the oil pressure into the cylinder chamber 41. The control operation of said line oil pressure can reduce the load applied to the hydraulic pump. |
