A scroll compressor includes a casing; an orbiting scroll; a fixed scroll; and a main frame which supports the orbiting scroll. The fixed scroll may include a fixed scroll end plate and a fixed scroll wrap which protrudes from the fixed scroll end plate. The main frame may include a main frame end plate which is provided on the opposite side of the fixed scroll end plate on the basis of the orbiting scroll, and a main frame side plate which protrudes from an outer circumferential portion of the main frame end plate toward the fixed scroll. The fixed scroll end plate, the main frame end plate, and the main frame side plate may form an orbiting space of the orbiting scroll.

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 type positive displacement assembly includes a first scroll and a second scroll, where the second scroll is configured to orbit with respect to a center of the first scroll without rotating with respect to the first scroll. Together, the first scroll and the second scroll define a compression chamber between two seal points where the first scroll and the second scroll contact one another as the second scroll orbits with respect to the first scroll during a compression cycle, and the two seal points come together proximate to a discharge port between the first scroll and the second scroll such that there is at least substantially no dead space between the first scroll and the second scroll at an end of the compression cycle. For example, the two seal points remain in sealing contact during at least one hundred and eighty (180) degrees of the compression cycle.

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 scroll compressor is provided that may include an orbiting scroll having an orbiting wrap, and which performs an orbiting motion; and a fixed scroll having a fixed wrap to form a compression chamber including a suction chamber, an intermediate pressure chamber, and a discharge chamber, by being engaged with the orbiting wrap. In a state in which the orbiting scroll and the fixed scroll are concentric with each other, when a distance between the orbiting wrap and the fixed wrap is defined as an orbiting radius, there exists an offset section having an interval larger than the orbiting radius, between a side surface of the orbiting wrap and a side surface of the fixed wrap which faces the orbiting wrap. With such a configuration, even if the fixed scroll or the orbiting scroll is transformed due to thermal expansion, interference between the fixed wrap and the orbiting wrap at a portion having a large transformation amount may be prevented. This may prevent a frictional loss or abrasion between the fixed wrap and the orbiting wrap. Further, this may restrict or minimize a gap between the fixed wrap and the orbiting wrap at an opposite side to the suction chamber, resulting in enhanced compression efficiency.

A scroll compressor is disclosed, which comprises an auxiliary discharge path capable of sufficiently making sure of a discharge area at an initial discharge stage. The compressor comprises a fixed scroll including a fixed end plate portion and a fixed wrap, and an orbiting scroll including an orbiting end plate portion and an orbiting wrap, wherein a discharge hole is formed in the fixed end plate portion, and an auxiliary discharge path for connecting a side of the orbiting wrap with a bottom surface of the orbiting wrap is provided to be communicated with the discharge hole, whereby a compressed refrigerant may be discharged through the auxiliary discharge path.

A scroll compressor is provided that may include a casing; a drive motor provided at an inner space of the casing; a rotational shaft coupled to a rotor of the drive motor, and rotated together with the rotor; a frame provided below the drive motor; a fixed scroll provided below the frame, and having a fixed wrap; and an orbiting scroll provided between the frame and the fixed scroll, having an orbiting wrap so as to form a compression chamber including a suction chamber, an intermediate pressure chamber, and a discharge chamber, by being engaged with the fixed wrap. In a state in which a center of the fixed scroll and a center of the orbiting scroll are substantially the same, an interval between the fixed wrap and the orbiting wrap gradually increases towards the suction chamber from the discharge chamber.

A scroll-type compressor includes: a movable scroll including a low-stage movable tooth portion having a spiral shape and protruding from a first side of a movable substrate portion in an axial direction, and a high-stage movable tooth portion having a spiral shape and protruding from a second side of the movable substrate portion in the axial direction; and a shaft arranged to extend through the movable substrate portion and causing the movable scroll to undergo revolution motion. A low-stage compression mechanism and a high-stage movable compression mechanism are provided on opposite sides of the movable substrate portion in the axial direction. The numbers of curling of the low-stage movable tooth portion and the high-stage movable tooth portion are set to be one.