| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable displacement pump capable of reducing a power loss by bringing a pump discharge pressure near to a required hydraulic pressure.SOLUTION: During high rotation of an engine, a solenoid selector valve 8 introduces hydraulic pressure into a second control oil chamber 17 through first and second solenoid control ports 55, 56 which have an orifice effect. On the other hand, a pilot valve 7 cuts off a communication state between a hydraulic pressure introduction port 45 and a first pilot control port 46 at an initial position where a first spool valve 42 is moved to maximum in the right direction while being biased by a first valve spring 44. When a discharge pressure increases, the pilot valve brings both ports 45, 46 into communication with each other and brings a second pilot control port 47 into communication with a first drain port 48 to control hydraulic pressure in a first control oil chamber 16.SELECTED DRAWING: Figure 11 |
