Abstract: a First gap (15) in a thrust direction between teeth bottoms of a fixed mirror plate (2b) and teeth tips of an orbiting lap (4a), and a second gap (16) in the thrust direction between teeth bottoms of an orbiting mirror plate 4b and teeth tips of a fixed lap (2a) are formed such as to gradually increase from an outer peripheral side to an inner peripheral side of a scroll compressor, the first gap (15) is made greater than the second gap (16). Contact surface pressures of the laps (2a) and (4a) are kept low with respect to pressure formation, contact pressure of the teeth tips of the fixed scroll part (2) and the teeth bottoms of the orbiting scroll part (4)are equally maintained. With this loads applied to the scroll parts (2) and (4)are equally received by a thrust surface.

Abstract: A scroll compressor includes an orbiting scroll engaged with a front case by pins and rings or ring holes to prevent rotation of the orbiting scroll. The rings or the ring holes have such an inside diameter that an orbiting radius defined by the pins and the rings or the ring holes is larger than a theoretical orbiting radius defined by engagement between gear surfaces of a fixed scroll and the orbiting scroll. The pins, the rings, or the ring holes are shifted in such a direction as to relieve twisting of the orbiting scroll relative to the fixed scroll.

Abstract: A coupling mechanism for a scroll compressor comprises an orbiting scroll disk, a retention bolt, a bearing shaft and a retention nut. The orbiting scroll disk includes a first face configured to engage a stationary scroll disk to compress a working fluid, and a second face having a hub. The retention bolt is inserted into the hub. The bearing shaft is fit onto the retention bolt and includes a bearing surface for engaging a drive bushing of a drive shaft. The retention nut is threaded onto the retention bolt to retain connection of the bearing shaft with the orbiting scroll disk.

Abstract: A scroll compressor is disclosed. A plurality of grooves (85) communicating with each other are formed on a sliding surface of a thrust bearing (53) subjected to the axial force received by a movable scroll (32). The areas surrounded by the plurality of the grooves (85) make up a plurality of insular pressure receiving portions (83) independent of each other. The pressure receiving portions (83) represent at least one half of the area of the sliding surface.

Abstract: The scroll machine has a first and a second scroll member each having intermeshed scroll wraps. A compensation member is attached to one of the scrolls. As the scroll machine warms to operating temperature, the compensation member exerts a force on the one scroll member causing it to deflect. The deflection of the scroll member compensates for the unequal growth of the scroll wrap which is caused by a temperature difference between the radially inner section and the radially outer section of the scroll wrap.

Abstract: A scroll compressor includes a feature for location of a housing shell section off of one of the scroll compressor bodies. According to this aspect, a scroll compressor comprises a housing including a shell section; scroll compressor bodies having respective bases and respective scroll ribs that project from the respective bases and which mutually engage about an axis for compressing fluid; and a drive unit operative to facilitate relative movement between the scroll compressor bodies. The shell section is located axially relative to a remainder of the housing off of one of the scroll compressor bodies.

Abstract: To provide a scroll type fluid machine which can ensure that even when the pressure ratio of the pressure P1 of its high pressure chamber (back pressure chamber) to the pressure P2 of its low pressure chamber (P1/P2) is low, its orbiting scroll be pressed against its fixed scroll without having its orbiting scroll increased in diameter to prevent any leakage of a fluid through between the front end face of the wall of its orbiting scroll and the bottom face of the end plate of its fixed scroll. The scroll type fluid machine has an Oldham's keyway (17) formed along the edge of the back side of the orbiting scroll end plate (13a) for holding one end portion of an Oldham's ring (10) slidably, and a sealing member (18) has a tongue part (18a) formed to cut off the flow of any fluid from the back pressure chamber to the Oldham's keyway (17).

Abstract: A scroll compressor an orbiting scroll member including a second end plate, a second wrap extending from the second end plate and meshingly engaged with the first wrap to form a suction pocket in fluid communication with a suction pressure region of the compressor, intermediate compression pockets, and a discharge pocket in fluid communication with the discharge passage. An auxiliary passage is in fluid communication with one of the intermediate compression pockets to provide pressurized fluid to the chamber to deflect the first end plate and the first wrap axially toward the orbiting scroll member.

Abstract: A scroll compressor includes a compression section having an orbiting scroll with volutes that are substantially symmetrically formed on both surfaces of an orbiting base plate. A main shaft penetrates through and is fixed to a center portion of the base plate. A pair of fixed scrolls is placed on both surfaces of the orbiting scroll, and has volutes which correspond to the respective volutes of the orbiting scroll to form compression chambers. The main shaft has a notch part which is formed at a portion penetrating through the orbiting scroll and fixed scrolls. A slider is provided which has an eccentric hole including a flat slide surface corresponding to the notch part. The slider is fitted to the main shaft where the notch part is formed. The slider is made slidable in a direction orthogonal to a length direction of the main shaft by the flat slide surface.

Abstract: A scroll compressor including a block, a fixed scroll, an orbiting scroll, a crankshaft, an Oldham ring and an oil passage is provided, wherein the fixed scroll is fixed on the block, and the orbiting scroll, the crankshaft and the Oldham ring are disposed on the block. The fixed scroll and the orbiting scroll form a gas-in area, a compressing area and a gas-out area which are connected in a series. The orbiting scroll is eccentric connected with the crankshaft to orbit over the fixed scroll and drive the Oldham ring moving. A reciprocating motion area on the block is formed via the reciprocating motion between the block and the Oldham ring, wherein the block has an oil opening in the reciprocating motion area. Besides, one terminal of the oil passage is connected to the oil opening, and another terminal of the oil passage is connected to the gas-in area and the compressing area.

Abstract: A scroll compressor is provided. The scroll compressor includes a fixed scroll and an orbiting scroll, each with a wrap extending from a plate. The wrap or the plate may have different heights so as to prevent a gap from forming between the end of one of the wraps and the opposite plate. Accordingly, performance of the compressor may be enhanced even if manufacturing tolerances are not precisely controlled or the compressor operates for an extended period of time. Furthermore, frictional loss due to increased frictional area of an edge of the plate may be prevented, and refrigerant leakage due to separation between the wrap and the plate may be prevented.

Abstract: In order to realize cost reduction in a gear pump apparatus by reducing form accuracy of a gear while securing pump performance, a running-in coating is provided on a tooth sliding contact portion when forming a confinement area in at least one of gears of the gear pump apparatus. By this feature, the running-in coating is gradually worn away and deformed according to rotary drive of the pump, and thus it is possible to obtain an optimal gear form in meshing combinations of the gears. Further, it is possible to reduce leakage inside the pump to secure the pump performance even if the form accuracy of the gear is reduced for the sake of the cost reduction.

Abstract: A scroll compressor may include a shell, a bearing housing, first and second scroll members, and a ring member. The bearing housing may be supported within the shell and may include at least three axially extending arms. The first scroll member may be supported on the bearing housing and may include a circumferential outer surface. The second scroll member may be supported on the bearing housing and may be meshingly engaged with the first scroll member. The second scroll member may be disposed between the first scroll member and the bearing housing. The ring member may include an open center portion surrounding the circumferential outer surface of the first scroll member therein. A portion of the ring member may be disposed between the arms of the bearing housing and the circumferential outer surface of the first scroll member.

Abstract: In a scroll-type fluid machine (4), a refrigerant in a discharge chamber (80) is adjusted at prescribed discharge pressure by using a discharge valve (84), discharged from a scroll unit (52), and supplied to a refrigeration circuit (2), and the machine has a circulation path (7) for introducing the refrigerant in the discharge chamber from the refrigeration circuit toward a drive casing (22) while maintaining the refrigerant pressure, and an inlet path (93) formed in a compression casing (24) and leads the refrigerant in the circulation path to the rear side of a movable scroll (54) to make the led refrigerant counteract the refrigerant discharge pressure acting on the front side of the movable scroll.

Abstract: A scroll compressor in which a scroll fixed lap rising from a fixed plate of a fixed scroll and a scroll orbiting lap rising from an orbiting plate of an orbiting scroll are combined with each other to form compression chambers therebetween, the fixed scroll is made of iron-based material, the orbiting scroll is made of aluminum-based material, at least the plate back surface of the orbiting scroll is subjected to surface processing.

Abstract: An apparatus for preventing vacuum of a scroll compressor is provided. The apparatus includes a fixed scroll having a bypass hole, through which a suction chamber of a casing is connected to a discharge chamber of the casing; a valve block having an inner channel, through which the bypass hole of the fixed scroll is connected to the discharge chamber of the casing, and fixedly installed at the fixed scroll; and a valve member disposed between the bypass hole of the fixed scroll and the inner channel of the valve block. Since the apparatus is assembled at an outer periphery of the fixed scroll, a processing error of the fixed scroll is prevented, thereby reducing production costs. Also, since foreign materials generated when a refrigerant channel is processed do not remain in a valve hole, the valve member is prevented from being mal-operated, productivity is enhanced, and fabrication costs reduced.

Abstract: A scroll compressor is provided with a passage for providing both an unloader function and an economizer injection function. This common passage communicates with separate ports. The ports that are exclusively used for by-pass unloading operation are open only during by-pass unloading operation, but blocked off by a check valve during vapor injection operation. The other, normally smaller vapor injection ports are open for both vapor injection and by-pass unloading operation. By utilizing these two sets of ports, a smaller total port area is provided for vapor injection operation and a much larger total open port area for by-pass operation. The different open port areas for by-pass unloading operation and vapor injection operation allows optimization of compressor operation at both of those regimes of operation.

Abstract: A compressor drive shaft may include a first bearing portion, a second bearing portion, and an intermediate portion disposed therebetween. The intermediate portion may include a continuous, nonlinear, central axis in an unloaded state.

Abstract: There is provided a scroll compressor in which reliability and durability is increased by preventing peeling of a coating layer applied to a thrust plate, to maintain a desired level of lubrication for a long period of time. The scroll compressor has a thrust plate, a coating which is applied to a surface of the thrust plate, a housing having a thrust bearing face to which the thrust plate is attached, an orbiting scroll member having a slide face which is supported by the thrust plate and which orbits while sliding, and a peeling prevention part which reduces a sliding pressure acting on an edge portion of the thrust plate from the slide face.

Abstract: A scroll compressor is provided with a cavity in its back pressure chamber to increase a volume of the back pressure chamber. In this manner, at start-up, the back pressure chamber will not be effective to bias the two scroll members together until this enlarged volume is filled with a compressed refrigerant. This reduces the load on the electric motor at start-up.

Abstract: A back pressure chamber (12) provided on a back surface of an orbiting scroll (5) is divided into an inner region (12a) and an outer region (12b) by an annular seal (11). A diameter d of the annular seal (11) is set 0.5 times or more of a diameter D of an orbiting mirror plate (5a). With this, plus thrust force can be applied to the orbiting scroll (5) irrespective of magnitude of a discharge pressure Pd applied to the inner region (12a). Therefore, it is possible to push the orbiting scroll (5) against the fixed scroll (4) only by back pressure of discharge pressure. A set pressure Pm of the outer region (12b) is reduced to a value close to a suction pressure Ps, a pressure adjusting mechanism (20) is swiftly opened after a scroll compressor is started. With this, lubricant oil is supplied from the outer region (12b) to the suction space (9) without a time lag.

Abstract: A scroll type compressor is disclosed. The scroll type compressor includes a housing, a frame, a compartment, a separator, a scroll pairs, a slider, a plurality of compartments, at least a pressure-regulating mechanism, and a guiding element. The compartment in the housing is separated into a high-pressure compartment, a low-pressure compartment, and a middle-pressure compartment. The separator is disposed between the high-pressure compartment and the low-pressure compartment. The separator includes an outlet at the center thereof, and at least a passage through the separator. When the pressure in the high-pressure compartment is less than that in low-pressure compartment, the pressure-regulating mechanism is opened to exhaust pressure from the middle-pressure compartment to the high-pressure compartment.

Abstract: An improved sealing mechanism for a positive fluid displacement apparatus, where sealing tabs are located on the orbiting scroll. The sealing tabs can be integrally formed with the orbiting scroll or disposed on a piston that is mounted on the orbiting scroll.

Abstract: A compressor may include a housing, a compression mechanism supported within the housing, and a seal assembly. The housing may include a suction pressure region and a first discharge passage in communication with a discharge pressure region. The compression mechanism may include a second discharge passage in communication with the first discharge passage. The seal assembly may be sealingly engaged with the housing and the compression mechanism to define a chamber and to provide sealed communication between the first and second discharge passages. The seal assembly may include a seal member engaged with the compression mechanism and including a leg having an opening therein. The leg may isolate the chamber from the discharge pressure region when in a first position and may provide communication between the chamber and the discharge pressure region through the opening when in a second position different than the first position.

Abstract: A rotary compressor includes a rotation mechanism, an annular piston and a blade. The rotation mechanism has a cylinder with an annular cylinder chamber. The annular piston is contained in the cylinder chamber eccentrically from the cylinder and sectioning the cylinder chamber into an outer compression chamber and an inner compression chamber. The blade is disposed in the cylinder chamber and sectioning each of the inner and outer compression chambers into a high-pressure side and a low-pressure side. The rotation mechanism compresses a fluid by relatively rotating the cylinder and the piston. The outer compression chamber serves as a low-stage side compression chamber for compressing a low-pressure fluid into an intermediate-pressure fluid. The inner compression chamber serves as a high-stage side compression chamber for compressing the intermediate-pressure fluid compressed in the low-stage side compression chamber into a high-pressure fluid.

Abstract: A compressor housing defines a motor accommodating chamber. The pressure in the motor accommodating chamber is equal to the pressure in a suction chamber. A first reservoir chamber is located in a discharge chamber. A second reservoir chamber is defined about the discharge chamber. A communicating passage connects the first reservoir chamber with the second reservoir chamber. A restrictor is located in the communicating passage. An oil return passage connects the second reservoir chamber with the suction chamber. A connecting passage connects the motor accommodating chamber with the suction chamber. Therefore, leakage of electricity is prevented.

Abstract: A scroll machine includes a shell and a pair of scroll members. At least one of the scroll members disposed in the shell is mounted for axial movement with respect to the other scroll member disposed in the scroll. The amount of axial movement of at least one scroll member is accurately controlled by providing a stop. The stop is defined by the contact of the end plate of the at least one scroll member with another member of the scroll machine which is accurately positioned within the shell of the scroll machine. The member can be either the shell or another component which engages the shell.

Abstract: A rotary fluid machine includes a first rotation mechanism and a second rotation mechanism. Each of them includes a cylinder having a cylinder chamber and an annular piston which is contained in the cylinder chamber and divides the cylinder chamber into an outer working chamber and an inner working chamber. The cylinder rotates around the piston. The first rotation mechanism and the second rotation mechanism are arranged to be adjacent to each other with a partition plate sandwiched therebetween. The cylinder of the first rotation mechanism and the cylinder of the second rotation mechanism are arranged such that one of the cylinders is provided at one side of a partition plate and the other is provided at the other side of the partition plate. Each of the first rotation mechanism and the second rotation mechanism is provided with a compliance mechanism for reducing a gap that occurs between the cylinders in the axial direction of the drive shaft.

Abstract: A scroll compressor may include a shell, a compression mechanism, and a sealing apparatus. The compression mechanism may be contained within the shell and include a compression member. The compression member may include an aperture extending radially there a surface. The sealing apparatus may be contained within the shell and include a first seal member and an actuator. The first seal member may be pivotally supported relative the compression member and may be movable from a first position wherein a sealing portion of the first seal member is in a sealing engagement with the surface and a second position wherein the sealing portion of the first seal member is displaced radially outwardly from the surface. The actuator may be engaged with the first seal member and configured to displace the first seal member from the first position to the second position.

Abstract: An improved sealing mechanism for a positive fluid displacement apparatus, where sealing tabs are located on the orbiting scroll. The sealing tabs can be integrally formed with the orbiting scroll or disposed on a piston that is mounted on the orbiting scroll.

Abstract: A scroll compressor has a moving scroll and a stationary scroll in contact with each other. A seal ring for defining a back pressure space at a rear side of the stationary scroll is provided and its position is adjusted between a sealing position and a leakage position with respect to an end plate of the stationary scroll.

Abstract: The drive connection between an eccentric pin and a slider block in a scroll compressor is angled such that any vertical force between the two will drive the slider block away from the orbiting scroll member. In this manner, manufacturing tolerances will not result in any drive connection which can have a net vertical force driving the slider block toward the orbiting scroll member.

Abstract: The invention relates to an axial piston engine with a filling pump integrated in a receiving bore of the axial piston engine, which filling pump comprises a gerotor set with an externally toothed inner ring and an internally toothed outer ring and also an inner thrust plate and an outer thrust plate. The two thrust plates enclose the gerotor set between them and, on their surfaces facing away from the gerotor set, are in each case supported via a pressure field seal, which surrounds the pressure field regions formed in the thrust plates, in such a way on the housing walls axially enclosing the filling pump that lateral play in the form of axial mobility of the filling pump is guaranteed.

Abstract: A scroll fluid machine is capable of readily providing a back-pressure chamber having an increased pressure-receiving area and yet capable of being reduced in size. A fixed scroll member is secured to a casing. An orbiting scroll member is provided at a position facing the fixed scroll member. A holder is provided at the back of the orbiting scroll member, and a coupling member is provided to face the orbiting scroll member across the holder. The coupling member couples together the orbiting scroll member and a driving shaft and performs an orbiting motion together with the orbiting scroll member. A back-pressure plate is provided at the back of the orbiting scroll member, and a back-pressure chamber is formed between the back-pressure plate and the holder.

Abstract: A scroll type fluid machine having a driving system including a counter weight and a sub weight, in which an efficiency of an assembling operation is enhanced by simplifying an assembling structure of the driving system. In the fluid machine, a sub weight (17) is provided on a rotary shaft (16) and a counter weight (20) is provided on a driving bush (19) . The driving bush (19) is attached to the rotary shaft (16) by an attachment bolt (23) to prevent relative rotation between the rotary shaft and the driving bush. The rotary shaft (16) supported by a main bearing (18) and is driven in rotation by a motor (9), with the result that an orbiting scroll (4) performs an orbiting motion with respect to a fixed scroll (2).

Abstract: In order to make a displacement type compressor be able to reliably start without increasing an outside diameter dimension of the compressor while using a self-start synchronous motor having high energy efficiency, the displacement type compressor according to the invention includes the self-start synchronous motor which starts as an induction-motor and performs synchronous operation by performing synchronization pull-in almost at a synchronous rotational frequency, a compression part having a compression chamber which compresses a working fluid, and a hermetic container which houses the self-start synchronous motor and the compression part. The displacement type compressor is provided with a start load reducing means which reduces a load of the compression part at startup and is-placed at the compression part in the hermetic container.

Abstract: A scroll machine is powered by a brushless permanent magnet motor. The rotor for the motor includes a rotor body formed by a plurality of laminations and an upper and lower counterweight made of zinc and located at opposite ends of the rotor body. An attachment member extends through the counterweights and the rotor body to secure the counterweights and the plurality of laminations. The counterweights include steel inserts which cooperate with the attachment member to provide a metal to metal clamping for the rotor body with a steel connection being maintained through the rotor.

Abstract: A scroll compressor has a moving scroll and a stationary scroll in contact with each other. A seal ring for defining a back pressure space at a rear side of the moving scroll is provided and its position is adjusted between a sealing position and a leakage position with respect to an end plate of the moving scroll.

Abstract: An oil discharge preventing apparatus of a scroll compressor comprises: a balance weight coupled to a rotor of a driving motor so as to offset an unbalance generated when an orbiting scroll performs an orbiting motion by receiving a rotation force of the driving motor; and a lower fixed oil guide fixedly coupled between the balance weight and the rotor, for preventing oil from being spread in a casing and guiding the oil downwardly to a bottom of the casing, whereby an oil leakage to the outside of the casing can be minimized, the number of construction components can be reduced, and assembling processes can be simplified.

Abstract: An apparatus for varying the capacity of a scroll compressor is disclosed. The apparatus for varying the capacity of a scroll compressor includes a bypass passage for connecting a compression pocket under intermediate pressure among compression pockets formed by a wrap of a fixed scroll and a wrap of a orbiting scroll and a suction side through which refrigerant is inhaled into the compression pocket to each other, an opening and closing device for opening and closing the bypass passage, and an elastic opening and closing device mounted in the bypass passage to open and close the bypass passage by the pressure of the compression pocket and the pressure and elasticity of the suction side according as the bypass passage is opened and closed by the opening and closing device. Therefore, it is possible to simplify the structure of varying the capacity of a compressor such that it is possible to reduce the size of the apparatus for varying the capacity of a scroll compressor and to thus reduce the number of parts.

Abstract: A scroll type compressor with an enhanced sealing arrangement includes two sealing rings, mounted one between a first part of a gliding block and a first chamber of a fixed scroll and another one between a second part of the gliding block and a second chamber of the fixed scroll, respectively. The sealing ring has a U-shape cross section characterized in having a center depth smaller than half of a total height of the cross section. By providing such sealing rings, damage in mounting the sealing rings can be reduced to a minimum, possible leakage from the damage can be avoided, the assembly process in producing the compressor can be improved, and the compressor can be successfully merchandized.

Abstract: A sealed type motor-driven compressor includes a cylindrical motor housing and an annular stator core fastened to the interior of the motor housing. A method of assembling the compressor includes fastening the stator core to the motor housing by mechanically deforming at least one of the motor housing and the stator core. It is thus possible to set the fastening interference between the motor housing and the stator core to a sufficiently great level for suppressing loosening of the stator core with respect to the motor housing, which may otherwise be caused by a relatively high pressure produced by refrigerant gas.

Abstract: In a scroll fluid machine, a stationary scroll fixed to a housing engages with an orbiting scroll to form a sealed chamber between the orbiting and stationary scrolls. Fluid in the sealed chamber is compressed or decompressed with revolution of the orbiting scroll with respect to the stationary scroll. A plurality of self-rotation preventing devices are provided on the orbiting scroll to prevent the orbiting scroll from rotating on its own axis. The self-rotation preventing device comprises an eccentric tube connected to a main shaft fitting in the housing, and an eccentric shaft fitted in a bearing plate. The eccentric tube is eccentrically revolved with respect to the main shaft thereby allowing engagement of the orbiting scroll with the stationary scroll to be adjusted.

Abstract: There is provided a scroll compressor having high overall adiabatic efficiency and reliability in a wide pressure operating range. A backside excess-suction-pressure region is provided such that pressure higher than suction pressure by a constant value is applied to a backside of scroll members to produce an attractive force to attract both scroll members. A control bypass is also provided for communicating compression chambers with a discharge system only when pressure in the compression chambers is high.

Abstract: A scroll compressor includes a first scroll and a second scroll. The first scroll has a step portion that separates an elevated portion and a recessed portion of a surface of the first scroll. A spiral wall of the second scroll has a step that separates an elevated portion and a recessed portion of the wall. A first bypass hole is provided in the elevated portion of the surface of the first scroll. A second bypass hole is provided in the recessed portion of the surface of the first scroll. The second bypass hole is within 360 degrees toward a center of the spiral of the first scroll from an outer end of the spiral. The first bypass hole is within 360 degrees from the second bypass hole toward the center of the spiral.

Abstract: A scroll compressor includes an orbiting scroll having a compressor chamber in an upper portion thereof and a bypass passage formed through upper and lower ends of a body thereof, a fixed scroll that allows the orbiting scroll to orbit therein to compress a coolant, an Oldham ring on which the orbiting scroll is seated, the Oldham ring having an upper chamber formed on an upper surface thereof with predetermined width and depth and a lower chamber formed on a lower surface thereof with predetermined width and depth, and a main frame on which the Oldham ring is seated.

Abstract: A scroll machine utilizes a floating seal to isolate pressurized fluid to provide axial biasing. The floating seal is designed as a single piece plate with inner and outer annular seals. The inner and outer annular seals can be U-shaped, V-shaped or L-shaped and each configuration is oriented to provide pressure actuation of the seal. Additional embodiments add a discharge valve, a high temperature protection system or a high pressure protection system to the floating seal.

Abstract: A scroll compressor is provided with spaced grooves in a base of one of the two scroll members. A recess is formed in a wrap tip of the other scroll member. The recess in the wrap tip bridges a space between the grooves of the other scroll member. This bridging equalizes pressure between two parallel intermediate compression chambers. Pressure equalization between the chambers improves compressor efficiency.

Abstract: There is provided, at a low cost, a small-size and lightweight scroll compressor capable of preventing a decrease in compression efficiency by utilizing a medium pressure between a suction pressure and a discharge pressure as a back pressure. An independent minute gap in the axial direction is provided between a main frame 3 and a thrust ring 8. This minute gap is used as a second back pressure chamber C2, and the medium pressure between the suction pressure and the discharge pressure is introduced into the second back pressure chamber C2.

Abstract: The present invention discloses an apparatus for varying a capacity of a scroll compressor. The apparatus comprises: a pressure control mechanism for controlling a pressure applied to the back of a orbiting scroll orbiting engaged with a fixed scroll; and a sealing varying mechanism for changing a sealing region of a orbiting scroll wrap and a sealing region of a fixed scroll wrap according to a change in the pressure applied to the back of the orbiting scroll. By this, the capacity of a refrigerant compressed by the fixed scroll and orbiting scroll using a high pressure in a casing can be varied to thus minimize the power consumption.