A compression unit of a rotary compressor includes a cylinder, an upper end plate that closes the upper side of the cylinder, a lower end plate that closes the lower side of the cylinder, and a piston that is fitted to a rotating shaft, revolves along an inner peripheral surface of the cylinder, and forms a cylinder chamber in the cylinder. At least one of an end face of the piston in the axial direction of the rotating shaft, a sliding surface of the upper end plate that slides with the end face of the piston, and a sliding surface of the lower end plate that slides with the end face of the piston, has formed therein an oil-film retention region having an array of a plurality of recessed portions that retain lubricating oil.

Oleophobic and/or philic surface(s) are utilized for oil separation, direction, and/or collection in a refrigeration system. Surfaces of component(s) of a refrigeration system (compressor, oil separator, evaporator, etc.) are produced to be oleophobic or philic. The oleophobic and/or philic surfaces are utilized to direct a flow path of oil within the refrigeration system or to prevent oil connection in an area. Refrigerant phobic and/or lubricant phobic material(s) also may be utilized to help promote separation of refrigerant vapor from refrigerant liquid and/or from oil in refrigeration systems.

Bearing 11 has base material 110 and coating layer 111. Base material 110 contains crank shaft 13 on an inner circumferential surface side. The inner circumferential surface of base material 110 is coated with coating layer 111. The inner circumferential surface side of base material 110 is coated with a resin with a thickness t, the resin is dried, and thereafter surface treatment is carried out such that multiple grooves C are provided on the surface of the resin so as to intersect with the direction of crank shaft 13, whereby coating layer 111 is formed. Peak portions B formed between adjacent grooves C come into contact with the outer circumferential surface of crank shaft 13 to support crank shaft 13. With bearing 11, the thickness of peak portions B at the center in the direction of the crank shaft 13 differs from the thickness of peak portions B at the end.

An integrated pressure plate and port plate, and method of forming same, for a pump includes a housing having a pumping chamber formed therein. The housing includes first and second metal pressure plate portions that form at least a portion of the pumping chamber wherein at least one of the first and second pressure plate portions has a hard coating formed of a different material than a remainder of the housing metal on a surface thereof where integrated ports are formed on surface(s) of the pressure plate portion(s). Surface irregularities relieve stresses and promote adhesion of the coating (e.g., tungsten carbide) to the underlying metal (aluminum alloy).

A roots pump includes a housing, a rotor chamber, a pair of rotary shafts, and a pair of rotors. The rotor chamber includes a rotor chamber peripheral surface facing a pair of distal end portions of each of the rotors. Each of the pair of the distal end portions includes: a pair of rotor peripheral surfaces facing the rotor chamber peripheral surface with a first radial clearance; and a distal end peripheral surface that is formed between the pair of the rotor peripheral surfaces in the rotational direction and faces the rotor chamber peripheral surface with a second radial clearance greater than the first radial clearance. A width of the rotor chamber peripheral surface facing the distal end peripheral surface in the rotational direction is greater than a sum of a pair of predetermined widths of the rotor chamber peripheral surface facing the pair of the rotor peripheral surfaces.

A rotor polishing device, including a housing with a space therein for holding rotors in need of polishing, an inlet for pumping a polishing lapper into the housing, and a rotational assembly for rotating the rotors during the polishing process. The rotor polishing device is useful for polishing rotors commonly used by rotary screw compression systems.

A compressor includes a cylinder including a cylinder chamber, a piston movably arranged relative to the cylinder in the cylinder chamber, and a sliding member slideable against the cylinder and the piston in the cylinder chamber. The cylinder and the piston are constructed from an AlSi alloy having a Si content exceeding 12.6 wt %, which is a eutectic point. The sliding member is constructed from steel and has a surface layer including a sliding surface slideable against the cylinder and the piston. The surface layer is treated so as to have greater hardness than hardness of proeutectic Si contained in the AlSi alloy, and the surface layer has hardness of at least Hv 1000 in the sliding surface.

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.

A moving part of a compressor, a compressor including the moving part, and a method of manufacturing the moving part, the moving part including a base material having a polished surface and including a steel material; an adhesive layer arranged on the polished surface; and a coating layer including diamond-like carbon. The adhesive layer may be arranged between the base material and the coating layer and bond the coating layer to the base material, and the base material may include an etching-processed area having a plurality of microgrooves (MG) extending in a downward direction into the base material from the polished surface.

A sealing arrangement is disclosed for use in a pump. The sealing arrangement can include a first pump component having a first face surface. The first face surface can have a sealing protrusion thereon. A second pump component can have a second face surface positioned in confronting relation to the first face surface. The second pump component can define a sealing cavity for holding a fluid under pressure. The sealing protrusion is positioned to engage the second face surface when the first face surface is pressed against the second face surface so that the sealing protrusion seals against the second face surface to prevent movement of the fluid from the sealing cavity past the sealing protrusion. Other embodiments are described and claimed.