A scroll compressor includes a compression mechanism having a fixed scroll and an orbiting scroll, a drive shaft engaging with the orbiting scroll, and a casing housing the compression mechanism and the drive shaft. An orbiting scroll thrust sliding surface is pressed against and in sliding contact with a fixed scroll thrust sliding surface. One of the thrust sliding surfaces is provided with an oil groove. A bearing oil supply passage provided inside the drive shaft does not communicate with the oil groove and is used to supply the lubricating oil in an oil reservoir in the casing to a bearing of the drive shaft. A sliding surface oil supply passage is used to supply the lubricating oil in the oil reservoir to the oil groove. The sliding surface oil supply passage has a sliding surface main passage provided inside the drive shaft.

A system includes a compressor with an orbiting scroll member having a first end plate and a first spiral wrap. A non-orbiting scroll member has a second end plate and a second spiral wrap, the second spiral wrap forming a meshing engagement with the first spiral wrap to create a plurality of compression chambers between a suction port and a discharge port. A first port in communication with a first of the plurality of compression chambers selectively injects an injection fluid into the first of the plurality of compression chambers to increase a compressor capacity and selectively leaks a first compressed fluid from the first of the plurality of compression chambers to reduce the compressor capacity. A second port in communication with a second of the plurality of compression chambers selectively leaks a second compressed fluid from the second of the plurality of compression chambers to reduce a compressor capacity.

Combining at least one centrifugal compression stage and at least one positive displacement compression stage in an integrally geared compressor to allow for different types of compression based on a temperature or a volume of gas to be compressed by the integrally geared compressor.

An electrically driven positive displacement compressor includes an electric drive motor configured to drive the compressor, the electric drive motor including a ring shaped electric stator and an electric rotor arranged inside the ring shaped electric stator and defining a cavity within the electric rotor. The compressor also includes a working chamber having an inlet and an outlet, the working chamber being arranged at least partially inside the cavity of the electric rotor. The compressor additionally includes a compressor rotor arranged inside the working chamber and coupled to the electric rotor.

A fluid pump includes a pump head and a motor coupled by a drive shaft. The pump head includes a pump inlet, a pump outlet, and a pumping stage in which a movable pump element is driven by the drive shaft. The motor includes a motor rotor and a motor stator. A connector couples the motor rotor and the drive shaft. The connector includes a plate rotatable with the drive shaft, fan blades attached to the plate for establishing a flow of air for cooling the motor, and one or more counterweights attached to the plate for reducing or eliminating imbalance created by certain forces generated by the pump during operation.

A positive displacement pump assembly includes a rotor housing defining a rotor cavity, and an end plate configured to at least partially close one end of the rotor cavity. Rotors are supported on and fixed to rotor shafts and extend through the rotor cavity. A first pair of bearings fixing the rotor shafts to the end plate. A second pair of bearings fixes the rotor shafts to the rotor housing, preventing relative axial movement between the rotor shafts and the rotor housing. The end plate is axially movable with the rotor shafts when the rotor shafts vary in axial length due to thermal fluctuations so that changes in an axial clearance at end faces of the rotors are reduced.

A turbocharger generating a vacuum negative pressure may include a compressor which receives, through a turbocharger shaft, a rotational force of a turbine which rotates based on exhaust gas from an engine and turbo-charges an intake which is supplied to the engine, and a motorless vacuum pump coupled to the turbine through a center housing which is coupled to the compressor and is configured to be rotated by the turbocharger shaft, thus generating a vacuum negative pressure.

In a screw compressor (20), a male rotor suction end bearing (96) and discharge end bearing (90 1, 90 2, 90 3) mount the male rotor suction end shaft portion (39) and discharge end shaft portion (40). A female rotor suction end bearing (98) and discharge end bearing (92 1, 92 2) mount the female rotor suction end shaft portion (41) and discharge end shaft portion (42). At least one valve (182; 282; 382 1,382 2,382 3; 82; 582-1,582-2; 682-1,682-2; 782-1,782-2) is along a lubricant flowpath and has an energized condition and a de-energized condition. At least one restriction (184; 84-1,84-2; 84-1, 84-2,84-3; 484 1,484-2,84-3; 84 1,84 2,584; 84-1,84-2,684; 84-1,84-2,784) is along the lubricant flowpath. The at least one valve and the at least one restriction are positioned to create a lubricant pressure difference biasing the rotors away from a discharge end of the case.

An eccentric bush assembly structure of a scroll compressor, in which an orbiting scroll is eccentrically coupled to a rotary shaft of a drive motor, including a bush body rotatably coupled to the orbiting scroll while being pinned to the rotary shaft of the drive motor by an eccentric shaft, the bush body having a friction prevention groove formed in a surface facing a tip surface of the rotary shaft so as not to come into frictional contact with the tip surface.

Pressure changing devices and methods of making and using the same are disclosed. One pressure changing device includes an elliptic cylinder and a piston that has an external surface with a trochoid cross-section. Another pressure changing device includes a piston and a rotating cylinder that has an internal surface with a trochoid cross-section. Another pressure changing device includes two fixed axes, one for rotation of one component and another for orbiting or oscillation of the other component. The devices and methods include stacked pressure changing devices with one or more common shafts. The pressure changing device may be easier and less expensive to manufacture and repair than prior pressure changing devices of the same or similar functionality, and can provide efficient gap sealing in a high-pressure expansion part of a compression or expansion cycle.