A variable displacement pump device includes a pump, a mover, a biasing member, first and second control chambers, and a controller. The first and second control chambers are provided between an inner periphery of a containing chamber of a housing and an outer periphery of the mover. Hydraulic oil is introduced from a discharge port into the first control chamber. The pump is configured to permit oil to be introduced from the discharge port into the second control chamber via a supply/discharge passage or to be discharged from inside the second control chamber. The second control chamber is located adjacent to any of the pump chambers in a discharge region or the discharge port via the mover. The controller is configured to switch states in which the second control chamber is opened and closed to the supply/discharge passage.

A liquid pump having a housing, an electric motor formed by a stator assembly arranged in the housing and a rotor, a liquid duct, a printed circuit board and a temperature sensor assembly which is received in the housing and has a temperature sensor associated with the liquid duct, the stator assembly and/or the temperature sensor assembly having at least one press-in contact which engages into a press-in opening in the printed circuit board, an alignment mechanism is provided, by way of which the press-in contact may be directly aligned relative to the printed circuit board.

A liquid pump having a housing, an electric motor formed by a stator assembly arranged in the housing and a rotor, a liquid duct, a printed circuit board and a temperature sensor assembly which is received in the housing and has a temperature sensor associated with the liquid duct, the stator assembly and/or the temperature sensor assembly having at least one press-in contact which engages into a press-in opening in the printed circuit board, an alignment mechanism is provided, by way of which the press-in contact may be directly aligned relative to the printed circuit board.

A variable displacement pump according to the present invention is notably configured such that the opening area of a variable metering orifice (MO) is variably controlled by a second control valve (6) as a spool valve having a second spool valve body (61). According to this type of the second control valve (6), a larger amount of movement (stroke movement) of the second spool valve body (61) can be ensured. Consequently, the opening area of the variable metering orifice (MO) can be controlled without being restricted by a range of variation in a proper discharge amount based on an amount of movement of a cam ring (2), thereby achieving sufficient energy conservation of the pump.

A variable displacement pump according to the present invention is notably configured such that the opening area of a variable metering orifice (MO) is variably controlled by a second control valve (6) as a spool valve having a second spool valve body (61). According to this type of the second control valve (6), a larger amount of movement (stroke movement) of the second spool valve body (61) can be ensured. Consequently, the opening area of the variable metering orifice (MO) can be controlled without being restricted by a range of variation in a proper discharge amount based on an amount of movement of a cam ring (2), thereby achieving sufficient energy conservation of the pump.

A rotary, self-priming, positive displacement pump is described. The pump may include a pump housing including an inlet and an outlet, a pump chamber including an upper wall, a lateral wall, and a floor, first and second rotary impellers in the pump chamber, and a pair of gears each secured to the first and second rotary impellers, and a pressure relief feature operable to relieve pressure developing in a relatively high pressure zone of the pump chamber. The gears mesh with each other to ensure that the vanes do not contact one another during rotation. The pressure relief feature may comprise one or more channels formed in the pump housing and/or the first and second rotary impellers. The channels connect the high pressure zone with another zone to redistribute pressure. The channels may include one continuous channel or alternatively, a plurality of unconnected channels.

A rotary, self-priming, positive displacement pump is described. The pump may include a pump housing including an inlet and an outlet, a pump chamber including an upper wall, a lateral wall, and a floor, first and second rotary impellers in the pump chamber, and a pair of gears each secured to the first and second rotary impellers, and a pressure relief feature operable to relieve pressure developing in a relatively high pressure zone of the pump chamber. The gears mesh with each other to ensure that the vanes do not contact one another during rotation. The pressure relief feature may comprise one or more channels formed in the pump housing and/or the first and second rotary impellers. The channels connect the high pressure zone with another zone to redistribute pressure. The channels may include one continuous channel or alternatively, a plurality of unconnected channels.

A pump apparatus includes a housing, a shaft, a rotor, a plurality of vanes, a pressure relief passage, and a bearing. The housing includes suction ports and discharge ports. The rotor and the vanes transport hydraulic oil to the discharge ports. The hydraulic oil is sucked from the suction ports. The pressure relief passage is defined in a portion of the housing facing an outer peripheral surface of the shaft. The pressure relief passage brings the discharge ports into communication with a low pressure region where the hydraulic oil is low in pressure. When a pressure of the hydraulic oil in the discharge ports is lower than a first predetermined pressure, the bearing keeps the pressure relief passage out of communication with a passage. When the pressure of the hydraulic oil in the discharge ports has increased to reach or exceed the first predetermined pressure, the bearing brings the pressure relief passage into communication with the passage.

A pump apparatus includes a housing, a shaft, a rotor, a plurality of vanes, a pressure relief passage, and a bearing. The housing includes suction ports and discharge ports. The rotor and the vanes transport hydraulic oil to the discharge ports. The hydraulic oil is sucked from the suction ports. The pressure relief passage is defined in a portion of the housing facing an outer peripheral surface of the shaft. The pressure relief passage brings the discharge ports into communication with a low pressure region where the hydraulic oil is low in pressure. When a pressure of the hydraulic oil in the discharge ports is lower than a first predetermined pressure, the bearing keeps the pressure relief passage out of communication with a passage. When the pressure of the hydraulic oil in the discharge ports has increased to reach or exceed the first predetermined pressure, the bearing brings the pressure relief passage into communication with the passage.

An oil pump fixation detecting apparatus includes an oil pump, a discharge state switching unit, a target oil pressure setting unit, a pressure regulator, and a fixation determining unit. The discharge state switching unit performs control of switching a discharge state of the oil pump from a full-discharge state to a partial-discharge state. The fixation determining unit determines that the oil pump is not fixed in the full-discharge state in a case where oil pressure in a high-pressure oil passage has dropped by a predetermined value or more within a predetermined time, and determines that the oil pump is fixed in the full-discharge state in a case where the oil pressure in the high-pressure oil passage does not drop by the predetermined value or more.