| 摘要 |
PURPOSE:To improve pressure control and flow control in a low pressure area by comparing the output of a pressure control gain circuit with that of a flow control gain circuit, and providing a minimum value selecting means which outputs a smaller value, whichever, to keep a change in a total of loop gain to a minimum. CONSTITUTION:Pressure in a variable capacity pump 10 is detected by a pressure sensor 1, while discharge flow is detected by a flow sensor 2. A difference between a pressure instruction and a pressure detection signal by an adder- subtractor 3 is output to an adder-subtractor 12, and a difference between its output and a pressure phase compensating circuit 11 is output to a pressure control gain circuit 5. An adder-subtractor 4 operates the difference thereof from a flow instruction. The outputs of the pressure control gain circuit 5 and a flow control gain circuit 6 are received by a minimum value selecting circuit 7 to output a smaller value, whichever. Since then, a proportional solenoid 12 which generates suction force in proportion to a control current from a power amplifier 8 controls discharge flow in the variable capacity pump 10. |
