A scroll compressor may include a back pressure passage that provides communication between a compression chamber and a back pressure chamber to guide refrigerant compressed in the compression chamber partially to the back pressure chamber. The back pressure passage may communicate with the compression chamber through a front end surface of a non-orbiting wrap axially facing an orbiting end plate. Accordingly, when an orbiting scroll tilts, the non-orbiting wrap may be spaced apart from the orbiting end plate to open a scroll back pressure hole, such that the compression chamber and the back pressure chamber communicate with each other to quickly vary pressure in the back pressure chamber to be adaptive to the pressure of the compression chamber. This may result in appropriately adjusting back pressure in the back pressure chamber according to an operating mode and/or operating conditions, thereby increasing a sealing power and suppressing or preventing excessive contact.

An aluminum alloy for sliding components contains 8.0-11.5% by mass of Si, 0.7-1.2% by mass of Cu, 0.2-0.6% by mass of Mg, 0.30-0.60% by mass of Mn, 0.10-0.30% by mass of Fe, 0.01-0.03% by mass of Cr, and balance Al with inevitable impurities, in which a tensile strength at 25 C. is within a range of 330 MPa or more and 380 MPa or less, the aluminum alloy does not contain, per 1182 m.sup.2, two or more crystallized products containing 1% by mass or more of Cu and having a circle equivalent diameter exceeding 5 m, and the aluminum alloy does not contain, per 1182 m.sup.2, two or more Cr-containing intermetallic compounds having a length of 8 m or more, and does not contain, per 4726 m.sup.2, two or more primary crystal Si particles having a circle equivalent diameter exceeding 10 m.

A scroll machine, in particular a scroll compressor, has a first scroll unit with a base and a scroll rib protruding from the base with a scroll rib tip, a second scroll unit with a base and a scroll rib protruding from the base with a scroll rib tip. The first scroll unit can be moved along an orbital path relative to the second scroll unit and the first scroll unit and the second scroll unit engage with each other to form pressure chambers, and the scroll rib of a scroll rib tip having a face seal abuts sealingly to the base of the respective other scroll unit. The base of the first scroll unit and/or the base of the second scroll unit include(s) a pocket with an insert plate arranged in the pocket. Also contemplated is a refrigeration system.

A scroll compressor includes a compression chamber that compresses a fluid, an outer peripheral passage into which the fluid flows from a motor chamber, and a suction passage draws in the fluid from the outer peripheral passage to the compression chamber. The compression chamber is defined by a fixed scroll and an orbiting scroll. The outer peripheral passage is defined by a third peripheral wall of a discharge housing member and a fixed peripheral wall of the fixed scroll. The suction passage is provided in the fixed peripheral wall and includes an upstream-side outer peripheral surface located between the suction passage and an electric motor in an axial direction of a rotary shaft. A distance from an axis of the rotary shaft to the upstream-side outer peripheral surface varies in the axial direction of the rotary shaft.

A scroll for a scroll compressor and a scroll compressor is disclosed. The scroll includes an end plate having first and second surfaces opposite to each other; a scroll wrap extending from the first surface of the end plate; and at least one oil hole including a first oil hole portion extending in the end plate, and a second oil hole portion extending in the end plate and the scroll wrap and extending from the first oil hole portion to a strip-shaped surface of the scroll wrap away from the end plate, the second oil hole portion having an opening in the strip-shaped surface of the scroll wrap. The oil hole reduces circulation rate of the lubricating oil and temperature of the discharged refrigerant.

A refrigerant compressor for air-conditioning systems and to a method for operating a refrigerant compressor, is based on the object of specifying a solution with which safe functioning of a refrigerant compressor is achieved and in which the effort during production of the refrigerant compressor and the costs are reduced.