An orbital scroll wrap and a fixed scroll wrap of a scroll compressor include respective scroll start portions each having a bulbous shape defined by connecting an involute start point of an outer-surface involute curve and an involute start point of an inner-surface involute curve to each other with a plurality of arcs. At least one of the scroll start portions has a tiered shape wherein an n number (where n≥2) of tiers each having the bulbous shape are stacked in an axial direction of a main shaft. Letting involute-start-point angles of the outer-surface involute curves in respective tiers of the scroll start portion having the tiered shape be φos(1), φos(2), φos(3), . . . , and φos(n) in order from tip to base of the scroll start portion, the following is satisfied: φos(1)>φos(2)>φos(3)> . . . >φos(n); and 0.3π<φos(1)-φos(n)<0.7π.

A scroll compressor includes fixed and movable scrolls having a fixed and movable side plates and fixed and movable side laps to form first and second compression chambers. The fixed-side plate includes a discharge port and a relief hole extending from the front face through to the back face. The relief hole communicates for a predetermined amount of time with each of the first and second compression chambers and is shared by the first and second compression chambers. The front face of the movable-side plate includes a recessed part allowing the second compression chamber and the discharge port to communicate. The second compression chamber, during a latter stage of compression, and the discharge port communicating via a gap formed between a tip of the fixed-side lap and the recessed part before communicating via a side face gap formed between the fixed-side lap and the movable-side lap.

In a scroll fluid machine, a thinned section (26) is provided in correspondence with a position at which the wrap height of a spiral wrap (15B, 16B) changes due to a step part. The thinned section (26) is provided on the front-side surface or the rear-side surface of a tooth tip section of at least one of the spiral wraps (15B, 16B) of at least one of partner scrolls (15, 16) respectively engaging with scrolls (15, 16). The thinned section (26) is provided in the direction in which the wrap thickness decreases so as to extend over at least a reduced-machining-accuracy area (27), which is an area where the machining becomes discontinuous due to at least a change in the wrap height. Thus, a contact failure between the spiral wraps (15B, 16B) is avoided in the area where the machining accuracy relatively decreases as a result of increasing the machining speed, thereby achieving both improved productivity and maintained performance.

A scroll compressor to compress fluid in a compression chamber formed by combining a scroll wrap of a fixed scroll and a scroll wrap of an orbiting scroll, the scroll wrap of the fixed scroll and the scroll wrap of the orbiting scroll each having a scroll inner end part having a bulb shape defined by an outer surface involute curve, an inner surface involute curve, and a plurality of arcs connecting an end of the outer surface involute curve and an end of the inner surface involute curve, at least one of the scroll inner end parts being formed in an n-tier stair-like shape in which n (n≧3) number of bulb shapes are stacked on top of one another in an upright direction of the scroll wrap, the scroll compressor being configured to satisfy φos (0)>φos (1)>φos (2)> . . . >φos (n−1) where involute roll angles of the outer surface involute curve in tiers of the stair-like shape of the scroll inner end part are φos (0), φos (1), φos (2), . . . , φos (n−1), respectively, from a wrap tip side to a wrap root side.

A method for manufacturing a compressor scroll that appropriately impinges cavitation bubbles on target regions of a scroll. The method includes the step of water jet peening by jetting cavitation bubbles generated underwater by a water jet at a first side of an end plate (13A) of the scroll (13), with a center (P1, P2, P3) of the cavitation bubbles being offset from a center (O) of the spiral shape of a wall portion (13B) on the end plate (13A) and the step portion (13Aa) and the stepped portion (13Ba) positioned at an outer peripheral portion of the cavitation bubbles (C).

A pump as provided includes an inlet, an outlet, and a scroll pumping element. The scroll pumping element includes a fixed scroll component having one or more fixed scrolls and orbiting scroll component having one or more orbiting scrolls for fluid pumping. The fixed scroll component and the orbiting scroll component are arranged so as to be capable of providing pressurized fluid to a thrust bearing and prevent contact between the fixed scroll component and the orbiting scroll component.

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.

Provided is a tip seal that makes it possible to improve the durability of a tip seal installed on the tooth tip of a wall even when a continuously inclined section is provided to the wall. The tip seal is provided with: a tip seal inclined section (7A) installed in a groove section of a wall in which the height changes continuously in a spiral direction; and a tip seal flat section (7B) that is installed in a groove section of the wall in which the height is fixed in the spiral direction and that is adjacent to the tip seal inclined section (7A). A recess (8) is formed at a position away from the adjacent area between the tip seal inclined section (7A) and the tip seal flat section (7B).

Scroll fluid machine (1) in which the dislodgement of a slide bush (56) and a spring (61), which are provided in an eccentric bush (36), is prevented. Provided in receiving hole (58) of eccentric bush (36) are slide bush (56), which is movable in the direction of eccentricity, and spring (61), which biases slide bush (56) in a moving direction. A spring holding section (56b) and engagement projections (56a) are formed on slide bush (56). After slide bush (56) is placed in the receiving hole (58), engagement projections (56a) engage with eccentric bush (36) in a state in which slide bush (56) has been moved by the biasing force of spring (61), thus preventing slide bush (56) from falling off the receiving hole (58), and the spring holding section (56b) prevents the spring (61) from falling off the receiving hole (58).

In this scroll fluid machine, a tip seal (7) that is in contact with facing end plates (5a) and that is for sealing in a fluid is provided to a tip seal groove (3d) formed on the tooth tip of a wall (3b). The tooth bottoms of the end plates (5a) have a shape in which a central section is deeper than a side section (5d3) in a width direction orthogonal to the spiral direction of a wall (5b). During operation, the protrusion amount (δ) when the tip seal (7) protrudes from the tooth tip of the wall (3b) in an inclined section and is in contact with the facing end plates is greater than the protrusion amount (δ) when the tip seal (7) protrudes from the tooth tip of the wall (3b) in a flat section and is in contact with the facing end plates.