A first rotor configured to rotate adjacent to a second rotor is disclosed. The second rotor includes a circular main body with a first axis of rotation and a vane extending radially from the main body. The first rotor includes a first curved surface that corresponds to a curve swept at a constant radius about a second axis of rotation, a second curved surface that corresponds to a curve swept by a leading edge of the vane when the second rotor is simultaneously rotated about the first axis of rotation and the second axis of rotation, a third curved surface that corresponds to a curve swept by a trailing edge of the vane when the second rotor is simultaneously rotated about the first axis of rotation and the second axis of rotation, and a vane-receiving groove disposed between the second curved surface and the third curved surface.

A compressor may include first and second scroll members, first and second bearing housings, and a motor assembly. The first scroll member includes a first end plate and a first spiral wrap extending from the first end plate. The second scroll member includes a second end plate and a second spiral wrap extending from the second end plate and intermeshed with the first spiral wrap to define compression pockets therebetween. The first bearing housing supports the first scroll member for rotation about a first rotational axis. The second bearing housing may support the second scroll member for rotation about a second rotational axis that is parallel to and offset from the first rotational axis. The motor assembly may be disposed axially between the first and second bearing housings and may include a rotor attached to the first scroll member. The rotor may surround the first and second end plates.

A scroll fluid machine that attenuates the bending stress applied to the base of a wall body having an inclined section. The scroll fluid machine is provided with a wall body inclined section in which the distance between the facing surfaces of an end plate of a fixed scroll and an end plate of a rotating scroll that face each other continuously decreases from the outer circumferential side toward the inner circumferential side. A mesh clearance that is a gap between wall bodies formed when the wall bodies mesh with each other is larger on the outer circumferential side of the inclined section than on the inner circumferential side of the inclined section. The mesh clearance is made larger by drawing the wall surface of a wall body further back toward the central side of the wall body in the thickness direction than the original wall surface profile thereof.

A vane pump including: a housing having a pump chamber; a rotor having a cylindrical peripheral wall portion accommodated in the pump chamber and having a pair of vane holding grooves facing each other in a diameter direction, and an oil chamber defined inside the peripheral wall portion to store lubricating oil; and a vane that is held in the pair of vane holding grooves and moves across the oil chamber in the diameter direction, is provided. At least one of an inner surface of the housing and an end face of the peripheral wall portion, which together with the inner surface defines a sliding interface, has an oil groove for the lubricating oil.

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.

Provided is a tip seal that makes it possible to improve the durability of a tip seal installed on the tooth tip of a wall even when a continuously inclined section is provided to the wall. The tip seal is provided with: a tip seal inclined section (7A) installed in a groove section of a wall in which the height changes continuously in a spiral direction; and a tip seal flat section (7B) that is installed in a groove section of the wall in which the height is fixed in the spiral direction and that is adjacent to the tip seal inclined section (7A). A recess (8) is formed at a position away from the adjacent area between the tip seal inclined section (7A) and the tip seal flat section (7B).

A positive displacement device includes a first cylinder, a second cylinder disposed within the first cylinder, and a third cylinder disposed around the first cylinder. An interior surface of the first cylinder and an exterior surface of the second cylinder define an inner cavity. An exterior surface of the first cylinder and an interior surface of the third cylinder define an outer cavity. A partition between the interior surface of the first cylinder and the exterior surface of the second cylinder divides the inner cavity into inner regions, and another partition between the exterior surface of the first cylinder and the interior surface of the third cylinder divides the outer cavity into outer regions. The second cylinder and the third cylinder orbit with respect to the first cylinder to create alternating regions of high pressure and low pressure in the inner regions and the outer regions.

A hermetic compressor is provided that may include a vane that is inserted into a roller, rotates with the roller, and is pushed out toward an inner circumference of a cylinder by rotation of the roller to divide the compression chamber into a plurality of spaces. The vane may include a body having a sealing surface that contacts the inner circumference of the cylinder and inserted into the roller; and a guide that extends from an axial end of the body in a direction crossing a direction the vane slides out, and that is slidably inserted into a guide groove formed on at least one of the first bearing or the second bearing to restrain the vane from sliding out of the roller toward the inner circumference of the cylinder.

A compressor may include first and second scrolls and a seal. The first scroll includes a first end plate and a first spiral wrap extending from the first end plate. The first end plate may define a discharge passage and an annular recess surrounding the discharge passage. The second scroll includes a second end plate and a second spiral wrap extending from the second end plate. The first and second spiral wraps cooperate to define a plurality of fluid pockets. The seal may be at least partially received in the annular recess and may cooperate with the first scroll to define a biasing chamber receiving fluid at an intermediate pressure. The seal may include inner and outer diametrical surfaces. The inner diametrical surface may include a plurality of first annular grooves. The outer diametrical surface may include a plurality of second annular grooves.

A positive displacement rotary compressor is designed for near isothermal compression, high pressure ratios, high revolutions per minute, high efficiency, mixed gas/liquid compression, a low temperature increase, a low outlet temperature, and/or a high outlet pressure. Liquid injectors provide cooling liquid that cools the working fluid and improves the efficiency of the compressor. A gate moves within the compression chamber to either make contact with or be proximate to the rotor as it turns.