A welding machine includes a welding power supply that generates a welding waveform during a welding operation, an internal combustion engine, and a generator that is operatively connected to the welding power supply to supply electrical energy to the welding power supply. The generator includes a rotor shaft driven by the internal combustion engine, and an end casting located at an end of the generator opposite the internal combustion engine. A rotary screw compressor is mounted to the end casting of the generator. A clutch mechanism couples the rotor shaft to the rotary screw compressor to selectively drive the rotary screw compressor by the rotor shaft.

A fluid pressure unit is provided with an inverter (17), a motor (10) controlled by the inverter, a pump (11) driven by the motor to discharge a fluid, a detector (16) configured to detect a pressure of the fluid, a flow rate of the fluid, or both, a controller (20) configured to control the inverter such that a pressure of the pump, a flow rate of the pump, or both becomes a predetermined value based on a detected value by the detector, and a suppressor (33) configured to suppress a change of an output of the inverter caused by a pulsation frequency component of the fluid included in the detected value.

A fluid pressure unit is provided with an inverter (17), a motor (10) controlled by the inverter, a pump (11) driven by the motor to discharge a fluid, a detector (16) configured to detect a pressure of the fluid, a flow rate of the fluid, or both, a controller (20) configured to control the inverter such that a pressure of the pump, a flow rate of the pump, or both becomes a predetermined value based on a detected value by the detector, and a suppressor (33) configured to suppress a change of an output of the inverter caused by a pulsation frequency component of the fluid included in the detected value.

An electric hydraulic actuator is provided with an electric motor and a gear pump driven in rotation by the electric motor. The electric motor includes a motor housing and a rotating shaft supported by the motor housing so as to be freely rotatable. The gear pump has a drive gear into which the rotating shaft of the electric motor is inserted and a driven gear meshed with the drive gear. A pump housing is configured to accommodate the drive gear and the driven gear on one end and has an installation concave portion open at the other end for accommodating part of the motor housing. The motor housing is attached to the pump housing with a gap formed between the motor housing and the pump housing in a radial direction of the rotating shaft. The gap includes an O-ring to elastically support the motor housing in the radial direction.

A gerotor pump having an inner rotor and an outer rotor, which is also the rotor of an electric drive, having a housing and a flange which closes the housing with the motor compartment, the rotor being arranged on a shaft and sealing against the flange at a gap, wherein, in addition to the gap, there is at least one device with which at least a partial pressure compensation takes place between the suction region of the gerotor pump and the motor compartment of the gerotor pump.

Disclosed herein is an integrated pump system in which a motor is directly coupled to a pump, preferably using a modular connection. The integrated pump system may operate in a uni-directional or bi-directional mode. The integrated pump system incorporates an internal cooling channel which directs the returning low pressure hydraulic fluid past the controller and the motor for cooling purposes. The low pressure hydraulic fluid is also directly fed into the coupling between the motor and the pump to provide both cooling and lubrication.

Improved bushing assembly (10) for supporting the shafts of the intermeshed rotors of a positive displacement rotary pump avoiding, jamming, said bushing assembly (10) comprising on a lateral surface (13) thereof at least one compensation tank (15; 16) facing a suction side of the pump and at least one bleed channel (14) which connects said compensation tank (15; 16) to the discharge side.

A gear pump that selectively directs lubrication to certain components within the pump. A system and method of retrofitting existing pumps to improve their longevity in the field. The system and method provides a clean, simple, efficient, and elegant improvement to current gear pump fuel delivery systems.

An improved screw pump such as, for example, a twin screw pump is disclosed. In one embodiment, the screw pump includes a casing, first and second intermeshing rotors, and a liner positioned between the first and second rotors and the casing. In use, the liner is arranged and configured to bend and/or pivot in unison with the first and second rotors under the axial hydraulic pressure experienced by the screw pump during use. In one embodiment, the liner may be arranged and configured to include an asymmetric axial stiffness to facilitate bending of the liner. In another embodiment, the liner may be arranged and configured in multiple segments, the segments being arranged and configured to pivot to approximate the bending of the rotor shafts.

A horizontal type rotary compressor includes a case including an inlet and an outlet and configured to store oil, a compressor having a compression space in which refrigerant is accommodated, a driver to drive the compressor, a rotating shaft to connect the driver and the compressor, an oil feed pipe disposed at a side of the compressor, a first plate configured to divide the case into a first area for the driver and a second area for the compressor. The first plate including a discharge hole through which compressed refrigerant is discharged from the compressor to the first area. A second plate dividing the case into the second area and a third area in which the oil feed pipe communicates with the outlet, and includes a second hole formed at the upper side to communicate the second and third areas. The first and second plates forming an oil flow path.