A rotary compressor is provided that may include a rotation preventing key between a roller and a rotary shaft, the roller being a separable-type roller assembled into the rotary shaft. The rotation preventing unit may constrain rotation of the roller and allow axial movement of the roller with respect to the rotary shaft. Thus, axial movement of the roller along the rotary shaft may be suppressed or prevented, and thus, friction loss and abrasion between the roller and a main bearing or between the roller or a sub bearing may be suppressed or prevented.

A screw rotor which is hollow has improved performance against heat, pressure, rust, and the like. A screw rotor includes a screw portion of which an outer periphery has teeth and grooves having a helical shape and extending by a predetermined length in an axial direction. A radial cross section of at least a part of the screw portion includes a cross section of an outer surface portion forming the teeth and the grooves, a cross section of an axial center portion, a cross section of a support portion that connects an axial center side of the outer surface portion and an outer diameter side of the axial center portion, and a cross section of a hollow portion formed by the support portions adjacent to each other in a rotational direction and an axial center side inner surface of a tooth bottom or a tooth tip. In at least the radial cross section of the screw portion, different members are continuously joined as an integral structure in a cross section of at least one of the axial center portion and the support portion and the outer surface portion.

A compression device includes at least: two interleaved scrolls each of which is made of an aluminum alloy, one of the scrolls, being a fixed scroll (3), and is fixed and the other scroll, which is an orbiting scroll and moves eccentrically without rotating. Also included are anti-rotation means made of an aluminum alloy and configured to allow anti-rotation of the orbiting scroll. The compression device also includes one flat thrust bearing configured to axially contain the orbiting scroll and is made of aluminum alloys or grades of cast iron. The compression device also includes coatings for promoting friction between the fixed scroll, the orbiting scroll, the anti-rotation means and the flat thrust bearing.

A hydraulic tool includes a stator and a rotor rotatably disposed within the stator. At least one of at least an inner portion of the stator and at least an outer portion of the rotor includes an insert comprising a hard material. A method of forming a hydraulic tool includes attaching at least one insert comprising a hard material to a surface of a stator or a surface of a rotor. A downhole motor or pump includes a stator and a rotor. The stator includes at least one insert comprising a hard material disposed over at least a portion of an interior surface thereof and a matrix material at least partially surrounding the at least one insert. The rotor includes at least one insert disposed over at least a portion of an exterior surface thereof and a matrix material at least partially surrounding the at least one insert.

Disclosed are a sealing structure and a scroll air compressor having the same. The sealing structure includes: an orbiting scroll including an orbiting scroll spiral tooth (11), the orbiting scroll spiral tooth (11) being provided with an orbiting scroll spiral tooth groove (12), an orbiting scroll wear-resistant sealing strip (30) being provided in the orbiting scroll spiral tooth groove (12); a stationary scroll including a stationary scroll spiral tooth (21) matched with the orbiting scroll spiral tooth (11), the stationary scroll spiral tooth (21) being provided with a stationary scroll spiral tooth groove (22), a stationary scroll wear-resistant sealing strip (40) is provided in the stationary scroll spiral tooth groove (22), the wear-resistant sealing strip (30) is divided into sections including a high-temperature and high-pressure section (30a) and a medium-temperature and medium-pressure section (30b). The sealing structure reduces costs of use and maintenance of the sealing strip; a buffer contact surface of the wear-resistant sealing strip (30) in contact with a scroll surface is flat, which improves performances of sealing and noise-reduction; a bottom surface of the wear-resistant sealing strip (30) is equipped with a sealing ring having a cross section in a shape of a circle or a circular tube, which improves the damping and buffering performances; thereby the performance of the air compressor is improved, and the use cost of the air compressor is also reduced.

A plunger pump includes a cylinder section having a cylinder chamber and a spacer section sliding against a portion of the plunger closer to a proximal end side than a portion of a plunger advancing and retracting into the cylinder chamber. The cylinder section is made of a material having first hardness, and the spacer section being made of a resin material having second hardness softer than the first hardness. A length in an axial direction from a proximal end of a sliding portion of the spacer section sliding against the plunger to a distal end of the spacer section is larger than a maximum stroke length of reciprocation of the plunger.

A linear compressor and a method for manufacturing a linear compressor are provided. A piston of a linear compressor may include a surface treatment body made of aluminum or an aluminum alloy; a first surface treatment provided on an outer surface of the surface treatment body by a first vacuum deposition process; and a second surface treatment provided on an outer surface of the first surface treatment by a second vacuum deposition process.

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 valve seat assembly including a housing having a cavity and a puck located in the cavity and connected to the housing. The puck having a greater hardness than the housing.

A rotary engine that starts and operates on compression-ignition of a heavy fuel without a secondary ignition source. The rotary engine includes a rotor housing that forms an epitrochoidal-shaped chamber having linear side portions extending between rounded end portions. A three-flanked rotor is disposed in the chamber to rotate and operate in a manner similar to that of a common Wankel-style rotary engine. The rotor and chamber are configured to provide a compression ratio sufficient to produce compression-ignition of a heavy fuel. The rotor includes apex seal and side seal mounting blocks formed from hardened materials and that are simply removable from the rotor for replacing apex and side seals. The apex seals may include multiple non-parallel seal members at each apex and the apex seals and the side seals may overlap or intersect a corner seal to increase sealing under high compression loads produced by the rotor/chamber configuration.