A vane pump includes a pump housing formed with a cylindrical inner space, intake ports and exhaust ports, a rotating shaft rotatably supported by the pump housing, a rotor received in the cylindrical inner space to be rotated by the rotating shaft, a cam ring disposed in the cylindrical inner space, a plurality of vanes held by the rotor to define plural pump chambers between the rotor and cam ring. Fluid sucked from the intake ports is pressurized and discharged to the exhaust ports. The vane pump is further provided with first and second pressure chambers and a throttle passage connecting the first and second pressure chambers. Pressurized fluid discharged from one of the exhaust ports is led to one of the two pressure chambers and pressurized fluid discharged form the other of the exhaust ports is led to the other of the pressure chambers while pressurized fluid is taken out from the second pressure chamber to be supplied to a fluid device.
A rotary pump apparatus includes a stator housing, a pump function component, at least two discharge ports, a ring shaped pressure chamber, an outflow passage and an interception wall. The pump function component is contained in the stator housing. The discharge ports discharge the operation fluid from the pump function component, and are opened into the ring shaped pressure chamber. The pressure chamber is formed in the stator housing and defined with an outer wall and an inner wall. The outflow passage is opened in the pressure chamber. The interception wall is formed in the pressure chamber by connecting one portion of the outer wall and one portion of the inner wall.
A hydraulic fluid pump (10), including a housing (12), a pumping apparatus (14), an inlet (16), a pressure chamber (17), an outlet (18), a bypass valve (20) and a diffuser (24). Wherein cavitation is reduced by using the diffuser (24) to supercharge fluid from the outlet (18) to increase the static pressure of the fluid entering the pumping apparatus (14). And wherein the inlet (16) and the diffuser (24) are designed to minimize the complexity, cost and packaging considerations of the hydraulic fluid pump (10).
In a vane pump, a bottom surface of a suction side low pressure passage is set to be below a bottom surface of a return passage of a flow control valve in a cross portion between the return passage and the low pressure passage.
An apparatus (30) for use in pumping hydraulic fluid includes a pump unit (32) which is driven by an electric motor (34). The electric motor (34) is mounted on a tubular stem (108) which extends axially outward from a manifold plate (44). A stator (100) of the electric motor (34) is fixedly connected with the tubular stem (108). A rotor (112) of the electric motor (34) encloses the stator (100). A hydraulic muffler (50) attenuates noise produced by the gear pump unit (32). The hydraulic muffler (50) includes a channel (58) which extends into the manifold plate (44) from a major side surface (63) of the manifold plate. To increase the ability of the hydraulic muffler (50) to attenuate noise, one or two compliant elements (152 or 166 and 168) are connected with the channel (58).
