A scroll compressor includes a bush having a shaft part and a balance weight part. The balance weight part is secured to an outer periphery of the shaft part by shrink-fitting. The shaft part includes: a cylindrical body part; and a cylindrical coupling part which extends outward from an axial end portion of the body part, and to which the balance weight part is joined. The bush satisfies the following requirements:
1.2≤D2/D1≤1.6; and  (a)
1.0≤[(D2−D3)/(D4−D2)]×E1/E2≤3.5,  (b)
where D1 is the outer diameter of the body part, D2 is the outer diameter of the coupling part, D3 is the inner diameter of the body part, D4 is the outer diameter of the balance weight part, E1 is the Young's modulus of the shaft part, and E2 is the Young's modulus of the balance weight part.

The present invention relates to a fixed displacement pump for use for conveying a hydraulic fluid in a closed hydraulic circuit, a closed hydraulic circuit, a construction machine and a method for operating a fixed displacement pump in a closed hydraulic circuit.

A scroll compressor may include an orbiting scroll; a non-orbiting scroll engaged with the orbiting scroll to form a pair of compression chambers between the orbiting scroll and the non-orbiting scroll; a back pressure chamber assembly coupled to the non-orbiting scroll to form a back pressure chamber to support the non-orbiting scroll toward the orbiting scroll; a first back pressure passage that connects a first intermediate pressure chamber in the compression chamber and the back pressure chamber; a second back pressure passage that connects a second intermediate pressure chamber having a higher pressure than the first intermediate pressure chamber and the back pressure chamber; and a back pressure control valve configured to selectively open and close the first back pressure passage and the second back pressure passage according to an operation mode. The back pressure control valve moves to a first position at which the first back pressure passage is open and the second back pressure passage is closed in a power operation, and moves to a second position at which the first back pressure passage is closed and the second back pressure passage is open in a saving operation.

In a scroll compressor (1) provided with a fixed scroll (3) and an orbiting scroll (5), an inclined portion is provided in which the inter-facing surface distance (L) between an end plate (3a) and an end plate (5a) that face each other decreases continuously from the outer peripheral side towards the inner peripheral side. The inclined portion is configured from wall inclined portions (3b1, 5b1) in which the height of a wall (3b, 5b) decreases continuously from the outer peripheral side towards the inner peripheral side, and end plate inclined portions (3a1, 5a1) in which a tooth bottom surface is inclined in accordance with the incline of the wall inclined portions (3b1, 5b1). The inclined portion is provided across a range of no less than 180 around the center of the spiral.

A screw compressor of the present invention comprises: a housing having a compression chamber; male and female rotors provided in the compression chamber; a driving shaft for rotating the male and female rotors; and a seal cover across which the driving shaft is provided, and further includes: an oil chamber provided at the seal cover, and returning, to the compression chamber, oil having leaked into the driving shaft; and a breather for injecting external air into the oil chamber. Therefore, the breather is provided at the upper part of the oil chamber and an oil recovery line is provided at the lower part thereof so as to cause a pressure difference between the upper and lower parts of the oil chamber, such that the flow of the oil having leaked into the driving shaft is smoothly recovered in the oil recovery line.

A rotary internal combustion engine has: a rotor; a housing circumscribing a rotor cavity, the rotor received within the rotor cavity, the housing having a peripheral wall and a side housing assembly secured to the peripheral wall, the side housing assembly having plates located at spaced apart ends of the peripheral wall, the plates defining seal running surfaces in sealing engagement with opposed end faces of the rotor, the plates made of silicon carbide.

The present disclosure relates to a motor driven compressor apparatus capable of reducing abrasion of an orbiting scroll by implementing decompression without a separate decompression mechanism when a compressor is driven and increasing efficiency of the compressor by adjusting the pressure of a refrigerant, wherein a flow path, which is configured to pass through a center of a cross section in a longitudinal direction, and a first pin insertion hole in one direction at which the eccentric bushing is disposed and configured to communicate with the flow path and into which a swing pin is inserted, are formed in the rotary shaft, a second pin insertion hole, into which the swing pin is inserted, is formed in the eccentric bushing in the other direction at which the rotary shaft is disposed, and the refrigerant leaks between the swing pin and the first pin insertion hole.

There is disclosed a compressor comprising a case comprising a discharging part provided one side and configured to discharge a refrigerant, the case defining a predetermined space for storing oil; a drive part comprising a rotor coupled to an inner circumferential surface of the case and having coils wound there around and configured to generate a rotation magnetic field, and a rotor mounted in the rotor and configured to be rotatable by the rotation magnetic field; a shaft extending in a state of being coupled to the rotor; a compression part lubricated by the oil in a state of being coupled to the shaft and configured to compress and discharge the refrigerant; and a sealing part extending from the stator towards the compression part and configured to induce the winding of the coil.

A scroll compressor may include an orbiting scroll; a non-orbiting scroll engaged with the orbiting scroll to form a pair of compression chambers between the orbiting scroll and the non-orbiting scroll; a back pressure chamber assembly coupled to the non-orbiting scroll to form a back pressure chamber to support the non-orbiting scroll toward the orbiting scroll; a first back pressure passage that connects a first intermediate pressure chamber in the compression chamber and the back pressure chamber; a second back pressure passage that connects a second intermediate pressure chamber having a higher pressure than the first intermediate pressure chamber and the back pressure chamber; and a back pressure control valve configured to selectively open and close the first back pressure passage and the second back pressure passage according to an operation mode. The back pressure control valve moves to a first position at which the first back pressure passage is open and the second back pressure passage is closed in a power operation, and moves to a second position at which the first back pressure passage is closed and the second back pressure passage is open in a saving operation.

A vane pump including a housing having a peripheral wall portion, a bottom wall portion, and a pump chamber; a rotor disposed in the pump chamber to be rotatable; a vane disposed to be slidable in the radial direction with respect to the rotor and partitioning the pump chamber into working chambers; and a reed valve that opens and closes a discharge hole of the bottom wall portion. A pressure relief groove is disposed in a portion of the bottom wall portion corresponding to the discharge section with a clearance secured between the peripheral wall portion and the pressure relief groove. When the vane overlaps the pressure relief groove, a pair of the working chambers on both sides of the vane in the rotational direction communicates with each other via the pressure relief groove.