A rotary internal combustion engine with a rotor body made at least in major part of a first material, with at least the contact surface of the rotor lands including a second material having a greater wear resistance than that of the first material with respect to frictional engagement with the portion of the inner surface of the internal cavity contacting the at least one land. For at least one of the end faces, the land(s) include(s) the first material and the contact surface is defined by a surface layer of the second material on the first material. A method of axially positioning a rotor of a rotary engine within an internal cavity of an outer body of the engine are also discussed.

A spiral compressor having a stationary spiral element with a stationary spiral wall, a rotating spiral element with a rotating spiral wall arranged on a rotatable plate which is engaged with the stationary spiral wall wherein several compression working spaces are formed, and a guide means intended for guiding the rotating spiral element and with at least two guiding pins arranged in a stationary manner, at least two recesses formed on a back of the rotating spiral element with running sleeves which are inserted therein in a radially movable manner, in which the guiding pins are received such that the inner surface of the running sleeves, during rotation of the rotating spiral element, rotates about the circumference of the guiding pins, and wherein a lock is formed in every recess which prevents an axial protrusion of the running sleeves out of the recesses.

A rotary internal combustion engine with a rotor body made at least in major part of a first material, including at least one land protruding axially from each of its end faces and defining a contact surface extending at a fixed position with respect to the end faces. The contact surface frictionally engages a portion of the inner surface of the internal cavity of the engine, and at least the outer surface of the land includes a second material. The second material has a greater wear resistance than that of the first material with respect to frictional engagement with the portion of the inner surface of the internal cavity contacting the land. A method of axially positioning a rotor of a rotary engine within an internal cavity of an outer body of the engine are also discussed.

Carbon dioxide compressors having one or more coatings with wear surfaces having electroless surface coatings are provided. Alternatively, propane compressors are contemplated having wear surface coatings. The coating is electrolessly applied and may comprise nickel and wear resistant particles, such as boron nitride. The electroless surface coatings for use with compressor machines improve corrosion and wear resistance, as well as anti-friction properties for compressors processing CO.sub.2 or C.sub.3H.sub.8 containing refrigerants. In certain aspects, a scroll machine has an Oldham coupling and/or lower bearing comprising aluminum and has an electroless surface coating comprising nickel boron nitride particles disposed on one or more wear surfaces. In other aspects, a reciprocating compressor has a wear surface, such as on a connecting rod and/or piston coated with an electrolessly applied nickel and boron nitride particle layer. Methods for making the electroless surface coatings are also provided.

A scroll compressor includes a first chamfered portion formed at a distal end potion of a spiral blade of a fixed scroll, a second chamfered portion formed at a distal end portion of a spiral blade of an orbiting scroll, a third chamfered portion formed at a bottom portion of the spiral blade of the fixed scroll, and a fourth chamfered portion formed at a bottom portion of the spiral blade of the orbiting scroll. An expression of 0<{(Av1+Av2)/2}/Ac<110.sup.4 is satisfied where a sectional area of a space between the first chamfered portion and the fourth chamfered portion is defined as Av1, a sectional area of a space between the second chamfered portion and the third chamfered portion is defined as Av2, and a sectional area of a compression chamber is defined as Ac.

The non-lubricated compressor (10) for compressing a gas, comprises: a stationary stator (12) with a housing (18) comprising a rotor cavity (20) delimited by a bottom wall (22), a top wall (24), and a lateral wall (26) connecting said bottom wall (22) and said top wall (24), a rotor element (14) arranged for rotation about an axis (z) within the rotor cavity (20) for compressing a gas therein, a self-supporting sealing element (16) arranged within the rotor cavity (20), wherein the sealing element (16) is made of an abradable carbon material, and comprises a wall portion (34) arranged on an inner surface of the lateral wall (26) of the rotor cavity (20).

Rotors formed by an additive manufacturing process are presented. In one example, a rotor includes a monolithically formed rotor body and a plurality of helically arranged lobes formed from a first material, wherein each of the plurality of lobes defines an internal cavity between an outer surface and a central aperture.

To provide a combination of a cylinder made of a hypereutectic AlSi alloy and a hard-carbon-coated piston ring both exhibiting excellent wear resistance, the piston ring is provided with a laminate coating at least on an outer peripheral sliding surface thereof; the laminate coating comprising a metal layer, a metal-containing, hard carbon layer, and a metal-free, hard carbon layer in this order from the substrate side; the laminate coating having Martens' hardness (indentation hardness) HMs of 5-13 GPa, indentation modulus E of 70-200 GPa, and a deformation ratio Rpe of 0.45 or less, which is expressed by a ratio (Wp/We) of plastic deformation energy Wp to elastic deformation energy We; and a ratio (Tmf/Tm) of the thickness Tmf of the metal-free, hard carbon layer to the thickness Tm of the metal-containing, hard carbon layer being 2-8.

A scroll compressor is provided that may include a casing having a sealed inner space; a drive motor provided in the inner space of the casing to generate a rotational force; a rotational shaft rotatably coupled to the drive motor; an orbiting scroll formed of an aluminum material, and coupled to the rotational shaft to perform an orbiting movement; a fixed scroll coupled to the orbiting scroll to form a compression space; and an Oldham ring coupled to the orbiting scroll, and formed of a sintered metal. With this structure, it may be possible to prevent the Oldham ring from being worn out due to contact with the orbiting scroll. Further, a weight loss portion or wear-resistant coating layer may be formed on a portion of the Oldham ring, thereby suppressing or preventing vibration noise of the scroll compressor from being increased due to a weight increase of the Oldham ring.

A gear pump includes a pump housing, a two meshed with a driven gear, a suction housing, and a suction cavity. The suction housing includes a body portion having first and second sealing disposed adjacent to outer diameters of the gears. A suction chamber wall is disposed between the first and second sealing surfaces and a sealing land is adjacent to a planar running surface of the pump housing. A flange of the suction housing has a third sealing surface disposed in contact with gear faces of the gears. The suction cavity is open to the inlet and defined in part by the suction chamber wall.