The disclosure provides a pump device capable of suppressing hydraulic amplitude and reducing noise or vibration associated with hydraulic amplitude while simplifying the structure. The pump device includes: a housing which defines a suction port, a discharge port, and an accommodation chamber; and a pump unit which is arranged in the accommodation chamber and which defines a pump chamber that expands and contracts to exert a pumping action including a suction stroke and a pressurization and discharge stroke on a fluid. The housing includes an air introduction hole that is opened to introduce air into the pump chamber at a predetermined opening timing immediately before the suction stroke is completed.

A cam ring is capable of moving while rolling on a cam support surface. The cam ring is provided such that within a range in which the cam ring can move on the cam support surface, an eccentricity amount increasing-side angle is always greater than an eccentricity amount decreasing-side angle. On a plane perpendicular to the rotation axis of a driving shaft, the eccentricity amount increasing-side angle is an angle, in a direction opposite to a rotation direction of the driving shaft, from a first reference line, which connects a tangent point between the cam ring and the cam support surface to a rolling center of the cam ring, to a starting end of a first discharge port. The eccentricity amount decreasing-side angle is an angle, in the rotation direction of the drive shaft, from the first reference line to a terminal end of the first discharge port.

A vane cell pump, including: a delivery chamber having an inlet and an outlet; a rotor which is arranged in the delivery chamber and has a rotor body and vanes which are accommodated by the rotor body such that they can be shifted radially; an end-facing wall which delineates the delivery chamber on an axial end-facing side; and a supporting element which is arranged axially between the end-facing wall and the rotor body and which supports the vanes at their radially inner vane ends, wherein the rotor body, the supporting element and each two vanes which are adjacent in the circumferential direction of the rotor form chambers, the volume of which varies when the rotor is rotating. A pressure equalization connection fluidically connects at least two of the chambers to each other.

A shunt-enhanced compression and pulsation trap (SECAPT) for a screw compressor assists internal compression (IC), reduces gas pulsation and NVH, and improves off-design efficiency, without using a slide valve and/or a serial pulsation dampener. The SECAPT includes an inner casing (e.g., an integral part of the compressor chamber) and an outer casing (e.g., surrounding part of the inner casing near the compressor discharge port) forming at least one diffusing chamber with a nozzle and a feedback region that provides a feedback flow loop between the compressor chamber and the compressor discharge port. The SECAPT automatically compensates cavity pressure to meet different outlet pressures (hence eliminating under-compression and/or over-compression when the discharge port opens), partially recovers potential energy associated with the under-compression (UC), and traps and attenuates gas pulsations and noise before the discharge port opens.

An embodiment of a system with a minute measure of pulsatility in a flow of a fluid is described that comprises a first pump configured to flow the fluid to a junction at a first flow rate that comprises a measure of pulsatility; and a second pump configured to flow a portion of the fluid from the junction at a second flow rate that is less than the first flow rate to produce a flow of the fluid at a third flow rate from the junction with a minute measure of pulsatility.

A motor oil pump assembly includes: an inner sound insulation enclosure encloses an oil pump component, and the inner sound insulation enclosure and the oil pump component define an inner sound insulation cavity filled with low-pressure oil, the inner sound insulation cavity is in communication with a low-pressure cavity of the oil pump component, and the inner sound insulation enclosure is provided with a sound insulation enclosure cavity; and a pre-tightening buffering component, where the pre-tightening buffering component includes a piston and an elastic member, the piston fits in with the sound insulation enclosure cavity and presses against an upper end cover of the oil pump component, and the elastic member is used to provide a pre-tightening force for tightly pressing the upper end cover, where the sound insulation enclosure cavity is in communication with a high-pressure cavity of the oil pump component.

An electric pump actuator for a continuously variable transmission includes a gear wheel pump, a first electric motor, a second electric motor, and an electric control unit. The gear wheel pump has a first gear wheel and a second gear wheel meshing with the first gear wheel. The first electric motor is for actuating the first gear wheel, and the second electric motor is for actuating the second gear wheel independent of the first gear wheel. The electronic control unit is arranged to control the first electric motor to transmit a first torque to the first gear wheel, and control the second electric motor to transmit a second torque to the second gear wheel that is set against the first torque in at least one rotation angle range.

A rotary pump includes: a housing featuring a housing inlet and a low-pressure space on a low-pressure side of the pump and featuring a housing outlet and a high-pressure space on a high-pressure side of the pump; a delivery chamber; a delivery rotor in the delivery chamber; a setting structure which can be moved in a first setting direction and, counter to the first setting direction, in a second setting direction in order to perform a setting movement which adjusts the specific delivery volume of the rotary pump; and at least a first setting chamber for charging the setting structure with a setting pressure which acts in the second setting direction, wherein the fluid pressure in the high-pressure space acts on a pressure equalization surface on the outer circumference of the setting structure resulting in an external additional force which acts on the setting structure in the first setting direction.

A high-pressure pump is configured to pressurize fuel. The high-pressure pump includes a relief valve device that is placed in a relief passage, which has one end part connected to a discharge passage in a housing while another end part of the relief passage is configured to be communicated with a suction passage in the housing. The discharge passage is configured to conduct the fuel, which is pressurized in and discharged from a pressurizing chamber. The relief valve device is configured to enable or limit a flow of the fuel between one side of the relief passage, at which the discharge passage is located, and another side of the relief passage, which is opposite to the discharge passage, at a valve opening time or a valve closing time of the relief valve device.

A rotary pump, preferably a vane cell pump or a pendulum slider pump, includes a stator and a rotor which rotates about a rotational axis within the stator. The rotor includes multiple delivery elements which move radially in relation to the rotational axis, and two adjacent delivery elements limit a delivery cell together with the outer surface area of the rotor and the inner surface area of the stator. At least two delivery cells, preferably two adjacent delivery cells, exhibiting a first maximum cell volume form a first delivery cell group and at least two other delivery cells, preferably two other adjacent delivery cells, exhibiting a second maximum cell volume form a second delivery cell group. The first maximum cell volume of the delivery cells of the first delivery cell group is larger than the second maximum cell volume of the delivery cells of the second delivery cell group.