A screw compressor for a utility vehicle has at least one female screw, at least one male screw that meshes with the female screw, and at least one screw compressor drive which drives the female screw.

This electric compressor (10) has: an accommodating case (15) that accommodates an inverter device (19) and includes an accommodating section body (31), a substrate support section (32) protruding from a bottom surface (31a) of the accommodating section body (31), and a cover member (34) that closes an opening in the accommodating section body (31); and an antivibration member (17) that is positioned between one surface (51a) of a head part (51) of a bolt (16) fastened to the substrate support section (32) and an inner surface (34a) of the cover member (34), and that is bonded to the one surface (51a) of the head part (51) and the inner surface (34a) of the cover member (34).

A rotary compressor includes a compression mechanism having a cylinder, a piston, and a Helmholtz muffler. The Helmholtz muffler has a resonance chamber in the compression mechanism and a communication groove formed on an end face of the cylinder to connect the cylinder and resonance chambers. The communication groove is open at the end face of the cylinder and has a pair of side wall portions and a bottom wall portion between the side wall portions. Each side wall portion has a first portion adjacent an open end of the communication groove and a second portion adjacent the bottom wall portion. A surface of the first portion is a flat or bowed surface. A surface of the second portion is a bowed surface having a predetermined curvature so as to be connected to the surface of the first portion and a surface of the bottom wall portion.

The disclosure provides a pump device capable of suppressing hydraulic amplitude and reducing noise or vibration associated with hydraulic amplitude while simplifying the structure. The pump device includes: a housing which defines a suction port, a discharge port, and an accommodation chamber; and a pump unit which is arranged in the accommodation chamber and which defines a pump chamber that expands and contracts to exert a pumping action including a suction stroke and a pressurization and discharge stroke on a fluid. The housing includes an air introduction hole that is opened to introduce air into the pump chamber at a predetermined opening timing immediately before the suction stroke is completed.

A rotary compressor includes a compressor housing that is provided with a refrigerant discharge portion and a refrigerant suction portion, and an accumulator that is fixed to the outer peripheral surface of the compressor housing and connected to the suction portion. The accumulator has a cylindrical body portion, which is formed of a resin material, an upper portion, which is formed of a metal material and closes an upper end of the body portion, and a lower portion, which is formed of a metal material and closes a lower end of the body portion, the upper portion is joined to the upper end of the body portion, and the lower portion is joined to the lower end of the body portion.

Disclosed herein is a rotary compressor capable of maintaining the overall dynamic balance and providing low vibration and low noise even at high speed operation and capable of improving efficiency by providing a communication passage to communicate operation chambers, which are provided inside each of the plurality of cylinders for compressing a refrigerant, to each other. The rotary-type compressor includes a housing, a drive motor provided inside the housing to generate power and having a stator and a rotor, and a compression unit that receives power from the drive motor and compresses the refrigerant. The compression unit includes a plurality of cylinders in which an operation chamber to compress the refrigerant is provided. The operation chambers provided in each of the plurality of cylinders are provided to have different volumes, and a balancer provided to maintain dynamic balance is provided only in the lower side of the rotor.

A compressor may include a shell, a bearing housing, an orbiting scroll, and a non-orbiting scroll. The bearing housing is supported within the shell and includes a central body and a plurality of arms. Each arm extends radially outwardly from the central body and has a first aperture. The orbiting scroll is supported on the bearing housing. The non-orbiting scroll is meshingly engaged with the orbiting scroll and includes a plurality of second apertures. Each second aperture receives a plurality of bushings and a fastener. The fastener extends through the bushings and into a corresponding one of the first apertures in the bearing housing to rotatably secure the non-orbiting scroll relative to the bearing housing while allowing relative axial movement between the non-orbiting scroll and the bearing housing.

A balance shaft module includes a balance shaft for receiving a driving force from a crankshaft of an engine by a driving gear and rotating inside a balance shaft housing, an oil pump gear being geared with the driving gear to rotate along with the driving gear, an oil pump shaft having the oil pump gear press-fitted therein and rotating as the oil pump gear rotates, and an oil pump assembly mounted in the oil pump shaft and pumping oil as the oil pump shaft rotates, wherein a pair of support rings is provided at both side surfaces of the oil pump gear to support both side portions of the oil pump gear in the oil pump shaft.

In a stepped scroll compressor, inclined surfaces (28, 29) of which heights are gradually reduced toward stepped portions are formed in a range W of at least 2ρ to 3ρ (here, ρ denotes a turning radius of a turning scroll) at (1) any one or both of inner peripheral end portions of high top lands (14H, 15H) of both scrolls and inner peripheral end portions of low bottom lands (14J, 15J) of the opposite scrolls corresponding to the inner peripheral end portions and (2) any one or both of outer peripheral end portions of high bottom lands (14K, 15K) of both the scrolls and outer peripheral end portions of low top lands (14I, 15I) of the opposite scrolls corresponding to the outer peripheral end portions, on the stepped portions (14F, 15F and 14G, 15G) of the top and bottom lands.

In an oil pump, an inner rotor and an outer rotor rotate to discharge the oil through a discharge port. The discharge port has an outer extension portion located on a radially inner side with respect to a root circle of the outer rotor and on a radially outer side of a tip circle of the outer rotor and an inner extension portion located on the radially inner side with respect to the tip circle of the outer rotor and on the radially outer side with respect to a root circle of the inner rotor. An inter-tooth chamber facing a partitioning portion that partitions the suction port from the discharge port comes into communication with the outer extension portion and the inner extension portion. Then, a tip seal portion defining the inter-tooth chamber intersects an outer edge of an opening of the discharge port.