Abstract: A relief valve of the present invention includes a valve housing (1) including an inlet (13) into which a fluid is introduced, a valve sliding path (3) extending from the inlet (13), and a release port (15) provided in a wall surface of the valve sliding path (3), a valve piston (21) slidably housed in the valve sliding path (3) while being pressed toward an inlet side, the valve piston (21) opening and closing the release port (15), and a valve stopper (37) provided in the inlet (13) to cross an end surface of the valve piston (21) in a slender shape, receiving and stopping the pressed valve piston (21), and disposing the valve piston (21) in a position where the valve piston closes the release port (15).

Abstract: A fluid pump includes a housing, a rotary shaft, and pump units which are contained in the housing and sucks in, pressurizes, and discharges fluid with being rotationally driven by the rotary shaft. The housing has a suction passage conducting the fluid from a suction port to the pump unit, a discharge passage conducting the fluid from the pump unit to a discharge port, a return passage returning a portion of the fluid flowing through the discharge passage to an upstream side of the pump unit, and a control valve controlling a flow of the returned fluid. The return passage is formed so as to conduct the returned fluid in the same direction as a flow of a sucked fluid flowing through the suction passage to make the returned fluid flow together with the sucked fluid.

Abstract: An air ejection port for ejecting air-mixed oil is structured with a first air ejection port provided on the inner peripheral side from an inscribed circle of an outer rotor and a second air ejection port provided on the outer peripheral side from a circumscribed circle of the inner rotor, the air ejection port can have an enlarged port area as the total of area of the first air ejection port and area of the second air ejection port in a state without being in communication with either of a suction port and a discharge port, and a disadvantage that a pump chamber of a previous stroke and a pump chamber of a subsequent stroke communicate with each other through the air ejection port can be avoided.

Abstract: An oil pump includes a housing (10, 20), a rotary shaft (30) which is supported by the housing, an inner rotor (71, 81) which is rotated in the housing integrally with the rotary shaft, an outer rotor (72, 82) which is rotated in the housing as being interlocked with the inner rotor, a rotor case (40) which is fitted into the housing and which contains the inner rotor and the outer rotor and supports an outer circumferential face of the outer rotor in a slidable manner, a side plate (50) which is arranged to be in contact with at least one annular end face of the rotor case, and an elastic member (60) which exerts an urging force to press the side plate to the annular end face of the rotor case. According to the above, slide resistance and operational torque can be reduced and constant side clearance can be maintained.

Abstract: An air ejection port for ejecting air-mixed oil is structured with a first air ejection port provided on the inner peripheral side from an inscribed circle of an outer rotor and a second air ejection port provided on the outer peripheral side from a circumscribed circle of the inner rotor, the air ejection port can have an enlarged port area as the total of area of the first air ejection port and area of the second air ejection port in a state without being in communication with either of a suction port and a discharge port, and a disadvantage that a pump chamber of a previous stroke and a pump chamber of a subsequent stroke communicate with each other through the air ejection port can be avoided.

Abstract: A fluid pump includes a housing, a rotary shaft, and pump units which are contained in the housing and sucks in, pressurizes, and discharges fluid with being rotationally driven by the rotary shaft. The housing has a suction passage conducting the fluid from a suction port to the pump unit, a discharge passage conducting the fluid from the pump unit to a discharge port, a return passage returning a portion of the fluid flowing through the discharge passage to an upstream side of the pump unit, and a control valve controlling a flow of the returned fluid. The return passage is formed so as to conduct the returned fluid in the same direction as a flow of a sucked fluid flowing through the suction passage to make the returned fluid flow together with the sucked fluid.

Abstract: Conventional multistage oil pumps could not have been used in an application where the pressure and the temperature are high. A multistage oil pump including two rotors that are connected in series in the direction of the rotation axis, wherein the respective rotors are accommodated in a rotor case separately across a spacer, the inside thereof being partitioned by the spacer part. The rotor case is in the form of an integral cylindrical part, and the spacer is integral with the rotor case. The rotors and the rotor case are made of a ferrous material, and the rotor case is fixed to a housing by positioning pins.

Abstract: An oil pump of the present invention includes a housing (10, 20), a rotary shaft (30) which is supported by the housing, an inner rotor (71, 81) which is rotated in the housing integrally with the rotary shaft, an outer rotor (72, 82) which is rotated in the housing as being interlocked with the inner rotor, a rotor case (40) which is fitted into the housing and which contains the inner rotor and the outer rotor and supports an outer circumferential face of the outer rotor in a slidable manner, a side plate (50) which is arranged to be in contact with at least one annular end face of the rotor case, and an elastic member (60) which exerts an urging force to press the side plate to the annular end face of the rotor case. According to the above, slide resistance and operational torque can be reduced and side clearance can be maintained at constant.

Abstract: An oil pump including an upstream pump unit including an upstream inner rotor and an upstream outer rotor; a downstream pump unit including a downstream inner rotor and a downstream outer rotor as being arranged adjacently to the upstream pump unit in a predetermined axis line direction; a rotary shaft concurrently rotating the upstream inner rotor and the downstream inner rotor; and a housing which contains the upstream pump unit and the downstream pump unit as supporting the rotary shaft and which includes an inlet port for sucking oil from the outside into the upstream pump unit, an ejection port for ejecting a part thereof to the outside in a pressurization process of the upstream pump unit, a communication port for providing communication between the upstream pump unit and the downstream pump unit, and a discharge port for discharging oil from the downstream pump unit to the outside.

Abstract: A water pump includes an engage mechanism 25 which is disposed between a pump body 21 and the end portion of a pump shaft 23 opposite to the side where an impeller 22 is attached, while engaging the pump shaft to the pump body against the urging force of the urging member which urges a mechanical seal 24. The engage mechanism includes an annular member 26 which is rotatably fitted to the pump shaft 23 while contacting the pump body 21, and a cylindrical engage pin 27 which pierces the pump shaft 23 in the diameter direction while sandwiching the annular member 26 with the pump body 21.

Abstract: The object is to provide a water pump which machining accuracy and assembling accuracy can be easily improved.

Abstract: A lubricating oil supplying device allows for the oil discharge amount to be more finely controlled by provision of many outlet ports, and by reducing the influence of vibration. Therefore, a spool valve unit and a pump are separately formed. The spool valve unit includes an open-close spool valve and a solenoid for controlling operation of this spool valve. Plural inlet passages and an outlet passage are formed in the spool valve. The spool valve opens or closes the inlet passages, and oil from the pump is introduced into these inlet passages. One side of the outlet passage communicates with the inlet passages, and the other side communicates with an engine. A passage for introducing the oil from an oil tank to a pump chamber is formed in the solenoid. When the solenoid is turned “OFF”, communication between the return passage and the inlet passages is interrupted by the spool valve, and the oil is discharged from the pump to the plural inlet passages.