An example apparatus includes an outer rotor having a first axial face and a second axial face opposite the first axial face, wherein the first axial face comprises a circumferential contour defining a plurality of lobe faces, and wherein the second axial face comprises a transformed circumferential contour defining a corresponding plurality of lobe faces, where the transformed circumferential contour comprises at least one of a scale transformation of the circumferential contour or a rotational transformation of the circumferential contour; and an inner rotor configured to rotate eccentrically within the outer rotor, thereby forming a gerotor element for a fluid pump.

An eccentric bush assembly structure of a scroll compressor, in which an orbiting scroll is eccentrically coupled to a rotary shaft of a drive motor, including a bush body rotatably coupled to the orbiting scroll while being pinned to the rotary shaft of the drive motor by an eccentric shaft, the bush body having a friction prevention groove formed in a surface facing a tip surface of the rotary shaft so as not to come into frictional contact with the tip surface.

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 μm.sup.2, two or more crystallized products containing 1% by mass or more of Cu and having a circle equivalent diameter exceeding 5 μm, and the aluminum alloy does not contain, per 1182 μm.sup.2, two or more Cr-containing intermetallic compounds having a length of 8 μm or more, and does not contain, per 4726 μm.sup.2, two or more primary crystal Si particles having a circle equivalent diameter exceeding 10 μm.

An eccentric bush assembly structure of a scroll compressor, in which an orbiting scroll is eccentrically coupled to a rotary shaft of a drive motor, including a bush body rotatably coupled to the orbiting scroll while being pinned to the rotary shaft of the drive motor by an eccentric shaft, the bush body having a friction prevention groove formed in a surface facing a tip surface of the rotary shaft so as not to come into frictional contact with the tip surface.

Vacuum pump (1), comprising a housing (2) having an inlet (4) and an outlet (6) and defining a chamber (8) within the housing (2), a rotor (10) for rotational movement about a rotational axis (AR) within the chamber (8), and at least a first and a second vane (22, 24) received in respective first and seconds slots (16, 18) formed in the rotor (10). The first and second slots (16, 18) are substantially parallel to each other, and a length (L.sub.V) of each vane (22, 24) is larger than a length (L.sub.S) of the respective slot. Production method of such a vacuum pump.

An eccentric bush assembly structure of a scroll compressor, in which an orbiting scroll is eccentrically coupled to a rotary shaft of a drive motor, including a bush body rotatably coupled to the orbiting scroll while being pinned to the rotary shaft of the drive motor by an eccentric shaft, the bush body having a friction prevention groove formed in a surface facing a tip surface of the rotary shaft so as not to come into frictional contact with the tip surface.

An eccentric bush assembly structure of a scroll compressor, in which an orbiting scroll is eccentrically coupled to a rotary shaft of a drive motor, including a bush body rotatably coupled to the orbiting scroll while being pinned to the rotary shaft of the drive motor by an eccentric shaft, the bush body having a friction prevention groove formed in a surface facing a tip surface of the rotary shaft so as not to come into frictional contact with the tip surface.

Vacuum pump (1), comprising a housing (2) having an inlet (4) and an outlet (6) and defining a chamber (8) within the housing (2), a rotor (10) for rotational movement about a rotational axis (AR) within the chamber (8), and at least a first and a second vane (22, 24) received in respective first and seconds slots (16, 18) formed in the rotor (10). The first and second slots (16, 18) are substantially parallel to each other, and a length (L.sub.V) of each vane (22, 24) is larger than a length (L.sub.S) of the respective slot. Production method of such a vacuum pump.

A method for producing a pendulum of a pendulum slide cell pump may include providing a prefabricated pendulum body and performing a post-machining operation on the pendulum body only at a plurality of contact locations at which the pendulum body contacts at least one of an inner rotor and an outer rotor of the pendulum slide cell pump.

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.