Abstract: The present invention provides an oil pump device capable of preventing foreign matters from getting caught at a sliding part of an oil pump, and thus of preventing a situation where the oil pump is locked and prevented from rotating. The oil pump device includes an oil pump connected to a supply target apparatus by a hydraulic circuit, the oil pump discharging and supplying oil to the supply target apparatus through the hydraulic circuit; a motor driving the oil pump; a trapping member interposed along the hydraulic circuit, the trapping member trapping a foreign matter mixed in the oil discharged from the oil pump; and a motor control unit controlling the motor to perform a normal control mode of driving the oil pump in a normal control rotation range and perform, at operational start of the oil pump, a lock-avoiding mode of driving the oil pump with a lock-avoiding rotational speed set in advance as a lower limit.

Abstract: Provided are an impeller and a centrifugal pump that can be simplified in structure and reduced in weight and cost, and that can be integrally molded by a mold or the like. In a centrifugal pump including a housing having an inlet, an outlet and an impeller chamber, an impeller is disposed in the impeller chamber and is rotationally driven by a driving shaft. The impeller includes: a shaft part connected to the driving shaft to rotate about an axis line extending toward the inlet; blades protruding radially outward from an outer periphery of the shaft part; and an annular shroud plate continuous with the blades so as to cover a tip side area of the blades in order to be disposed adjacent to an inner wall of the housing on the inlet side.

Abstract: Provided are an impeller and a centrifugal pump that can be simplified in structure and reduced in weight and cost, and that can be integrally molded by a mold or the like. In a centrifugal pump including a housing having an inlet, an outlet and an impeller chamber, an impeller is disposed in the impeller chamber and is rotationally driven by a driving shaft. The impeller includes: a shaft part connected to the driving shaft to rotate about an axis line extending toward the inlet; blades protruding radially outward from an outer periphery of the shaft part; and an annular shroud plate continuous with the blades so as to cover a tip side area of the blades in order to be disposed adjacent to an inner wall of the housing on the inlet side.

Abstract: In a hydraulic circuit including a second oil pump (21) as a dedicated pump for supplying oil pressure to a VVT (23, 24), the exhaust side VVT (24) has a rotor and a return spring for holding the rotor in a most advance angle state in stoppage of an engine. By obtaining driving force of the second oil pump (21) from an exhaust side camshaft (26) to which the rotor is connected, it is possible to reduce an increase in a torque required for operating the exhaust side VVT (24) through energizing force of the return spring.

Abstract: There are provided a plunger pump and method of controlling discharge of the pump capable of obtaining a desired compression rate, changing a discharge amount with ease without changing a stroke of the plunger and/or the inner diameter of a sliding hole of the plunger, and discharging a constant amount of fluid with accuracy while preventing the fluid from leaking.