| 摘要 |
PURPOSE:To keep constant the discharge quantity of an operation fluid at all times by a method wherein two pressure chambers of each of cylinder units are made to communicate with the upstream side and the downstream side, respectively, of a variable orifice provided in a fluid discharge passage and an actuator for varying the sectional area of the orifice is provided. CONSTITUTION:The cylinder units 23 and 24 are provided in the moving direction of a cam ring 10 which is movably supported within a housing 4 so that the cam ring 10 is reciprocated by the cylinder units and the pressure chambers 31 and 33 of the cylinder unit 23 and the pressure cylinders 32 and 34 of the cylinder unit 24 are made to communicate with the upstream side and the downstream side, respectively, of the variable orifice 44 provided in the discharge passage 41 for the operation fluid. Further, the actuator 54 adopted to vary the sectional area of the opening of the orifice 44 is provided. Accordingly, it is possible to reciprocate or oscillate the cam ring 10 by thrust members 21 and 22 through the operations of the cylinder units 23 and 24 effected due to the pressure difference between the front and the rear part of the orifice 44 and to adjust automatically the amount (l) of excentricity of the center O2 of the cylindrical cam surface 11 of the cam ring 10 from the axis O1 of the rotor 1 due to the above mentioned pressure difference whereby the discharge quantity of the operation fluid is kept constant irrespective of an increase in the number of revolution of the pump. |
