A pump assembly may include a rotor having a rotor shaft portion; a stator having a bore portion defining a bore for receiving the rotor shaft portion; and a circumferential protrusion extending radially into the bore between the bore portion and the rotor shaft portion, wherein at least one of the protrusion and a corresponding surface of the rotor shaft portion or the bore portion is configured to be abraded by the other upon experiencing contact therewith. In this way, the gap between the bore portion and the rotor shaft portion may be at least partially filled by the circumferential protrusion in order to provide a seal. The protrusion and one of the bore portion and the rotor shaft portion may be formed from different hardness materials.

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 scroll compressor includes a first chamfered portion formed at a distal end portion 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.

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.

Rotors formed by an additive manufacturing process are presented. In one example, a method of making a rotor is presented including defining a printing order for the application of a first material, and creating a plurality of lobes arranged helically about a central opening or a shaft by adding a first material in the printing order, wherein each of the plurality of lobes defines an outer surface.

A screw pump includes a male screw, a female screw, a motor, a journal, a bearing member, and a case. The motor includes an output shaft, which transmits a torque to the male screw, and the motor is operable to drive the male screw to rotate the same through the output shaft. The journal is rotatably placed between the output shaft of the motor and the male screw. The bearing member rotatably supports the journal. The case includes a screw receiving hole that receives the male screw and the female screw. The journal and the male screw are coaxially and non-detachably integrated together. The output shaft and the journal are fitted together by clearance fit that enables transmission of the torque between the output shaft and the journal.

This piston includes a piston main body made of aluminum or an aluminum alloy, used in an internal combustion and a modified layer formed on a surface of a strength reinforced portion of the piston main body, having a surface made of aluminum oxide by plasma oxidation, to which compressive residual stress is applied.

A component for a downhole tool includes a rotor and a hardfacing precursor. The hardfacing precursor includes a polymeric material, hard particles, and a metal. A hydraulic drilling motor includes a stator, a rotor, and a sintered hardfacing material on an outer surface of the rotor or an inner surface of the stator. Methods of applying hardfacing to surfaces include forming a paste of hard particles, metal matrix particles, a polymeric material, and a solvent. The solvent is removed from the paste to form a sheet, which is applied to a surface and heated. A component for a downhole tool includes a first hardfacing material, a second hardfacing material over the first hardfacing material and defining a plurality of pores, and a metal disposed within at least some of the pores. The metal has a melting point lower than a melting point of the second hardfacing material.

An impeller 1 for a pump includes a cylindrical bush 13 rotatably held at an eccentric position within a cylindrical pump housing via a rotating shaft 3 and a plurality of vanes 11 that are fixed to an outer circumferential face of the bush 13 and radially extend to divide the inside of the pump housing into a plurality of compartments 14, each of the vanes 11 being made of a rubber-like elastic material and being formed inclined in a rotational direction of the bush 13 relative to a radial direction from the rotating shaft 3 of the bush 13.

A scroll compressor includes scroll members that are made of austempered grey iron in whole or in part. The austempering process can increases fatigue strength and toughness of a grey iron while maintaining its good machinability and vibration damping characteristics. Use of austempered grey iron scroll members allows the scroll compressor to improve its capacity, efficiency, and durability.