A compressor may include first and second scroll members, a driveshaft, first and second bearings, and first and second Oldham couplings. The scroll members define compression pockets. The first bearing may define a first rotational axis about which the first scroll member rotates. The second bearing may support the second scroll member for rotation about a second rotational axis that is offset from the first rotational axis. The first Oldham coupling may include a first body and a plurality of first keys extending from the first body. The first keys may engage slots formed in the second scroll member. The second Oldham coupling is separate and distinct from the first Oldham coupling. The second Oldham coupling may include a second body and a plurality of second keys extending from the second body. The second keys may engage slots formed in a surface that rotates about the first rotational axis.

A compressor may include a shell, first and second scroll members, a floating seal, a muffler plate, and a wear ring. The shell defines a discharge chamber and a suction chamber. The floating seal may sealingly engage the second scroll member. The muffler plate defines the discharge chamber and the suction chamber. The wear ring may sealingly engage the muffler plate and the floating seal such that the wear ring, the muffler plate, and the floating seal fluidly isolate the discharge chamber from the suction chamber. The muffler plate may include an axially facing surface that contacts the wear ring. The axially facing surface may include an annular recess. The wear ring may at least partially cover the annular recess. The annular recess may provide clearance between the muffler plate and the wear ring to allow the wear ring to deflect relative to the muffler plate during compressor operation.

A compressor may include first and second scrolls, an axial biasing chamber, and a modulation control valve. The second scroll includes an outer port and an inner port. The outer and inner ports may be open to respective intermediate-pressure compression pockets. The modulation control valve may be in fluid communication with the inner port, the outer port, and the axial biasing chamber. Movement of the modulation control valve into a first position switches the compressor into a reduced-capacity mode and allows fluid communication between the inner port and the axial biasing chamber while preventing fluid communication between the outer port and the axial biasing chamber. Movement of the modulation control valve into a second position switches the compressor into a full-capacity mode and allows fluid communication between the outer port and the axial biasing chamber while preventing fluid communication between the inner port and the axial biasing chamber.

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.

An oil-free water-injected screw air compressor comprises a housing that encloses two rotors for generating compressed air, and an air water separator for separating the water from the compressed air. Water injection can effectively cool a compressor, and some embodiments provide a sealing system for isolation of compressor bearing lubricant from water used for cooling.

A scroll type positive displacement assembly includes a first scroll and a second scroll, where the second scroll is configured to orbit with respect to a center of the first scroll without rotating with respect to the first scroll. Together, the first scroll and the second scroll define a compression chamber between two seal points where the first scroll and the second scroll contact one another as the second scroll orbits with respect to the first scroll during a compression cycle, and the two seal points come together proximate to a discharge port between the first scroll and the second scroll such that there is at least substantially no dead space between the first scroll and the second scroll at an end of the compression cycle. For example, the two seal points remain in sealing contact during at least one hundred and eighty (180) degrees of the compression cycle.

The invention relates to a vacuum pump for a motor vehicle, comprising a pump housing surface, on which a noise reduction hood delimiting a sound damping volume is mounted. The invention is characterized in that a multi-functional decoupling element is located between the pump housing surface and the noise reduction hood, said element carrying out a sealing function and a valve function in addition to a sound decoupling function.

Downhole tools for earth-boring applications may include a component of a steel material and including a bore. An inner surface defining the bore may be treated with a surface treatment. The surface treatment may include a nitrided region having nitrogen diffused into the steel material and a ceramic material adjacent to the nitrided region; the ceramic material defining the inner surface. Methods of making downhole tools for earth-boring applications may involve exposing a component of the downhole tool to an elevated temperature to heat the component in a nitrogen-rich environment. Nitrogen may be diffused into a steel material of the component and a nitrided region may be formed at one or more surfaces of the component. A ceramic material may be coated on the nitrided region of the component.

A suction groove is formed in an inside wall surface of a pump cover and is communicated with a suction passage of the pump cover. The suction groove extends along a rotational path of external teeth of an inner rotor and a rotational path of internal teeth of an outer rotor. An edge of a portion of the pump cover, which forms the suction groove, includes chamfered edge parts, which are chamfered, and unchamfered edge parts, which are not chamfered and are not rounded. Each of the unchamfered edge parts is located in a direct-inflow region of the suction groove, which overlaps with the suction passage in a view taken in a direction of a rotational axis, and each of the chamfered edge parts is located in a corresponding one of peripheral regions, which are other than the direct-inflow region.

An inner gear includes an insertion hole, which extends through the inner gear in an axial direction, and a first balance groove, which is axially recessed at an axial end portion of the inner gear and is communicated with the insertion hole. First and second chamfered portions are formed in an inner peripheral edge of the inner gear, which is adjacent to the insertion hole. A joint member has a leg inserted into the insertion hole. An inserting direction of the leg into the insertion hole is defined as a first direction, and a direction, which is opposite from the first direction, is defined as a second direction. In a view taken in a direction perpendicular to the axial direction, at least a part of a first direction side end portion of the leg is axially placed between a first chamfered end plane and a first groove end plane.