Scroll compressor

Abstract

This scroll compressor is provided with: a sealed container that constitutes an outer shell; a drive mechanism part that is disposed in the sealed container and that serves as a drive source; a first compression mechanism part that has a first fixed scroll fixed to the inside of the sealed container, and has a first oscillating scroll that forms a first compression chamber between the first fixed scroll and the first oscillating scroll and performs eccentric motion with respect to the first fixed scroll; and a second compression mechanism part that has a second fixed scroll fixed to the inside of the sealed container, and has a second oscillating scroll that forms a second compression chamber between the second fixed scroll and the second oscillating scroll and performs eccentric motion with respect to the second fixed scroll; and a drive shaft that is rotated by the drive mechanism part and that transmits the drive force of the drive mechanism part to the first oscillating scroll and the second oscillating scroll. The first compression mechanism part and the second compression mechanism part are arranged such that the first compression mechanism part is arranged between the drive mechanism part and the second compression mechanism part in the axial direction along the drive shaft, and the eccentric directions of the first oscillating scroll and the second oscillating scroll are reverse in the rotation direction of the drive shaft.

Description

Scroll Compressor

[0001] The present disclosure relates to a scroll compressor having a multi-stage compression mechanism, which is mainly installed in refrigerators, air conditioners, water heaters, and the like.

[0002] A scroll compressor is known in which two compression mechanisms are arranged in a sealed container, and a refrigerant compressed by one compression mechanism is further compressed by the other compression mechanism (see, for example, Patent Document 1). The scroll compressor in Patent Document 1 includes a drive mechanism that drives the orbiting scrolls of the two compression mechanisms via a drive shaft, and the drive mechanism is arranged between the two compression mechanisms above and below it. A first eccentric shaft and a second eccentric shaft are provided at the lower and upper ends of the drive shaft, and the orbiting scroll of the lower compression mechanism is driven by the first eccentric shaft, and the orbiting scroll of the upper compression mechanism is driven by the second eccentric shaft.

[0003] International Publication No. 2018 / 131111

[0004] However, in the scroll compressor of Patent Document 1, because the compression mechanism units, each having a spiral structure, are arranged above and below the main shaft of the drive shaft, a single main bearing and sub-bearing bear the gas load and centrifugal force of both the upper and lower spiral structures, resulting in a larger bearing load than in a single-stage scroll compressor. Furthermore, in the scroll compressor of Patent Document 1, because the compression mechanism units are arranged above and below the main shaft of the drive shaft, the eccentric directions of the first and second eccentric shaft units, i.e., the eccentric directions of the two orbiting scrolls, are substantially the same to balance the moment around the center of gravity of the main shaft. In this case, a balancer is provided to balance the translational direction, but the balancer in the scroll compressor of Patent Document 1 is also larger than in a single-stage scroll compressor.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to reduce the bearing load and the size of the balancer compared to conventional scroll compressors equipped with multiple compression mechanism parts.

[0006] a first compression mechanism having a first fixed scroll fixed in the sealed container and a first orbiting scroll that forms a first compression chamber between the first fixed scroll and the first fixed scroll and performs eccentric movement relative to the first fixed scroll; a second compression mechanism having a second fixed scroll fixed in the sealed container and a second orbiting scroll that forms a second compression chamber between the second fixed scroll and the second fixed scroll and performs eccentric movement relative to the second fixed scroll; and a drive shaft that is rotated by the drive mechanism and transmits the driving force of the drive mechanism to the first orbiting scroll and the second orbiting scroll, the first compression mechanism and the second compression mechanism being disposed between the drive mechanism and the second compression mechanism in an axial direction that is along the drive shaft, and the eccentric directions of the first orbiting scroll and the second orbiting scroll are opposite to each other in the rotation direction of the drive shaft.

[0007] In a scroll compressor according to the present disclosure, two compression mechanisms are disposed on the same axial side of a drive mechanism, and the orbiting scrolls of the two compression mechanisms are disposed so that their eccentric directions are opposite to each other. As a result, the gas load and centrifugal force acting on the first orbiting scroll cancel out the gas load and centrifugal force acting on the second orbiting scroll. Therefore, according to the present disclosure, in a scroll compressor having multiple compression mechanisms, it is possible to reduce the bearing load and the balancer size compared to conventional scroll compressors.

[0008] 1. A longitudinal sectional view of a scroll compressor according to embodiment 1. A sectional view of the first fixed scroll of FIG. 1. A bottom view of the first fixed scroll of FIG. 1. A top view of the first fixed scroll of FIG. 1. A partial sectional view showing the configuration of the discharge section of the first compression mechanism of FIG. 1. A top view of the drive shaft of FIG. 1. A longitudinal sectional view showing the flow of refrigerant in the scroll compressor of FIG. 1. A ph diagram of a refrigeration cycle when a scroll compressor of a comparative example is used. A ph diagram of a refrigeration cycle when the scroll compressor according to embodiment 1 is used. A longitudinal sectional view showing the flow of refrigeration oil in the scroll compressor of FIG. 1. A longitudinal sectional view showing a first modified example of the scroll compressor of FIG. 1. A longitudinal sectional view showing a second modified example of the scroll compressor of FIG. 1.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below. Also, the size relationships of the components in the drawings may differ from those in reality.

[0010] Embodiment 1. FIG. 1 is a vertical cross-sectional view of a scroll compressor 100 according to Embodiment 1. FIG. 2 is a cross-sectional view of the first fixed scroll 1 of FIG. 1. FIG. 3 is a bottom view of the first fixed scroll 1 of FIG. 1. FIG. 4 is a top view of the first fixed scroll 1 of FIG. 1. FIG. 5 is a partial cross-sectional view showing the configuration of the discharge section of the first compression mechanism 35 of FIG. 1. FIG. 6 is a top view of the drive shaft 7 of FIG. 1. The scroll compressor 100 according to Embodiment 1 has the function of drawing in a fluid such as a refrigerant, compressing it, and discharging it in a high-temperature, high-pressure state. The configuration of the scroll compressor 100 will be described with reference to FIGS. 1 to 6. Hereinafter, the scroll compressor 100 will be defined as a two-stage scroll compressor equipped with two compression mechanism sections.

[0011] 1, the scroll compressor 100 includes a sealed container 11 that forms an outer shell. The sealed container 11 houses a first compression mechanism 35, a second compression mechanism 36, a drive mechanism 37, a drive shaft 7, and the like. The lower portion of the sealed container 11 serves as an oil reservoir 20.

[0012] Within the sealed container 11, a first compression mechanism 35 is disposed above the drive mechanism 37, and a second compression mechanism 36 is disposed further above the first compression mechanism 35. The scroll compressor 100 performs two-stage compression, with the first compression mechanism 35 acting as a low-stage compressor and the second compression mechanism 36 acting as a high-stage compressor. In other words, the scroll compressor 100 compresses a fluid in the first compression mechanism 35, and then further compresses the fluid in the second compression mechanism 36.

[0013] The sealed container 11 has three internal spaces: a low-pressure space 22 into which fluid is sucked by the first compression mechanism 35, an intermediate-pressure space 23 into which fluid compressed by the first compression mechanism 35 is discharged, and a high-pressure space 24 into which fluid compressed by the second compression mechanism 36 is discharged. The sealed container 11 is provided with a suction pipe 8 that communicates with an external pipe (for example, a pipe connected to an evaporator of the refrigerant circuit), and the suction pipe 8 communicates with the low-pressure space 22 of the internal space. The sealed container 11 also has a discharge pipe 9 that communicates with an external pipe (for example, a pipe connected to a condenser of the refrigerant circuit), and the discharge pipe 9 communicates with the high-pressure space 24 of the internal space.

[0014] The first compression mechanism 35 has a function of compressing fluid drawn from a low-pressure space 22 formed below the first compression mechanism 35 within the sealed container 11 and discharging the fluid to an intermediate-pressure space 23 within the sealed container 11. The second compression mechanism 36 has a function of compressing fluid drawn from the intermediate-pressure space 23 and discharging the fluid to a high-pressure space 24 formed above the sealed container 11. The high-pressure fluid discharged to the high-pressure space 24 is discharged to the outside of the sealed container 11 through a discharge pipe 9. The drive mechanism 37 has a function of driving the first orbiting scroll 2 constituting the first compression mechanism 35 and the second orbiting scroll 5 constituting the second compression mechanism 36 in order to compress the fluid. Specifically, the drive mechanism 37 causes the first orbiting scroll 2 and the second orbiting scroll 5 to revolve via a drive shaft 7 (i.e., a crankshaft), thereby compressing the fluid in the first compression mechanism 35 and the second compression mechanism 36.

[0015] Also provided within the sealed container 11 are a first Oldham's ring 25 that prevents the first orbiting scroll 2 from rotating on its axis while allowing the first orbiting scroll 2 to revolve, and a second Oldham's ring 26 that prevents the second orbiting scroll 5 from rotating on its axis while allowing the second orbiting scroll 5 to revolve. The first Oldham's ring 25 is disposed between the first orbiting scroll 2 of the first compression mechanism 35 and the frame 3 disposed below the first orbiting scroll 2. In FIG. 1 , the second Oldham's ring 26 is disposed between the second orbiting scroll 5 of the second compression mechanism 36 and the first fixed scroll 1 of the first compression mechanism 35 disposed below the second orbiting scroll 5.

[0016] The first Oldham ring 25 and the second Oldham ring 26 each include, for example, an annular ring portion, a pair of opposing first Oldham keys formed on the upper surface of the ring portion, and a pair of second Oldham keys formed on the lower surface of the ring portion, which face each other in a direction perpendicular to the direction in which the pair of first Oldham keys face each other. The pair of first Oldham keys formed on the upper surface of the first Oldham ring 25 are respectively arranged in a pair of first swing key grooves 2e formed in the first orbiting scroll 2 and are slidable in one direction. The pair of second Oldham keys formed on the lower surface of the first Oldham ring 25 are respectively arranged in a pair of frame key grooves 3e formed in the frame 3 and are slidable in a direction intersecting the above-mentioned one direction. With this configuration, the first orbiting scroll 2 revolves (i.e., eccentrically orbits) without rotating. The pair of first Oldham keys formed on the upper surface of the second Oldham ring 26 are respectively arranged in a pair of second swing key grooves 5e formed in the second orbiting scroll 5 and are slidable in one direction. A pair of second Oldham keys formed on the underside of the second Oldham ring 26 are inserted into a pair of first fixed key grooves 1e (see FIG. 4) formed in the first fixed scroll 1, respectively, and are slidable in a direction intersecting the one direction described above. With this configuration, the second orbiting scroll 5 revolves (i.e., makes an eccentric orbiting motion) without rotating on its axis.

[0017] The upper surface of the frame 3 is a first thrust bearing 3s (see FIG. 5) that receives the thrust load of the first compression mechanism 35. The upper surface of the first fixed scroll 1 is a second thrust bearing 1s (see FIG. 5) that receives the thrust load of the second compression mechanism 36.

[0018] The first compression mechanism 35 has a first fixed scroll 1 and a first orbiting scroll 2. In the first compression mechanism 35, the first orbiting scroll 2 is disposed on the lower side, i.e., the side of the drive mechanism 37, and the first fixed scroll 1 is disposed on the upper side, i.e., the side of the second compression mechanism 36. The first fixed scroll 1 has a first fixed base plate 1c and a first fixed scroll body 1b, which is a spiral protrusion provided on one surface (lower surface) of the first fixed base plate 1c. The first orbiting scroll 2 has a first orbiting base plate 2c and a first orbiting scroll body 2b, which is a spiral protrusion provided on one surface (upper surface) of the first orbiting base plate 2c. Here, the first fixed scroll body 1b and the first orbiting scroll body 2b each have a shape extending along a curve such as an involute or an algebraic spiral. The first fixed scroll 1 and the first orbiting scroll 2 are provided in a sealed container 11 with the first fixed scroll 1b and the first orbiting scroll 2b meshing with each other. A first compression chamber 12 is formed between the first fixed scroll 1b and the first orbiting scroll 2b, and the first compression chamber 12 moves radially inward and reduces in volume as the first orbiting scroll 2 eccentrically orbits.

[0019] The first fixed scroll 1 is fixed to a sealed container 11. The first fixed scroll 1 is formed with a first discharge port 1a that discharges compressed intermediate-pressure fluid. A first valve 15 made of a leaf spring is disposed at the outlet opening of the first discharge port 1a to cover the outlet opening and prevent backflow of the fluid. A first valve guard 14 is disposed above the first valve 15 to limit the lift amount of the first valve 15. In other words, as the first compression chamber 12 moves and its volume decreases, the fluid in the first compression chamber 12 is compressed to a set pressure (intermediate pressure). When the first discharge port 1a opens to the first compression chamber 12, the first valve 15, which had been closing the first discharge port 1a, is lifted against its elastic force, and the compressed fluid is discharged from the first discharge port 1a into the intermediate-pressure space 23.

[0020] 2 and 3, a cylindrical central space SP1 extending in the axial direction (direction of arrow Z) is formed in the center of the first fixed scroll 1. More specifically, the first fixed scroll 1 has a generally cylindrical central tube portion 1d located radially inward of the first fixed scroll body 1b, which separates the first compression chamber 12 from the central space SP1. That is, the first fixed scroll 1 also functions as a frame for the second compression mechanism 36. As described with reference to FIGS. 2 and 3, the central space SP1 is provided in the center of the first fixed scroll 1, and therefore the first discharge port 1a is provided radially outward of the center of the first fixed base plate 1c, i.e., midway along a curve such as an involute or algebraic spiral of the first fixed scroll body 1b.

[0021] As shown in Fig. 4, a pair of first fixed keyways 1e are formed on the surface (upper surface) of the first fixed base plate 1c opposite to the surface on which the first fixed scroll 1b (see Fig. 1) is provided, in which a pair of second Oldham keys formed on the lower surface of the second Oldham ring 26 (see Fig. 1) are respectively disposed. As shown in Fig. 5, a counterbore 1f is formed on the upper surface of the first fixed base plate 1c in which a first valve 15 for opening and closing the first discharge port 1a and a first valve guard 14 are housed. As shown in Fig. 4, the counterbore 1f and the pair of first fixed keyways 1e are spaced apart on the upper surface of the first fixed base plate 1c.

[0022] As described with reference to FIG. 5 , by providing the counterbore 1 f in the upper surface of the first fixed base plate 1 c and accommodating the first valve 15, the first valve 15 can be installed in the first compression mechanism 35 while avoiding interference with the second Oldham ring 26 (see FIG. 1 ) and the second orbiting scroll 5.

[0023] 1, the first orbiting scroll 2 is disposed above the frame 3, which is disposed above the drive mechanism 37. As described above, the first orbiting scroll 2 revolves relative to the first fixed scroll 1 without rotating on its axis, due to the first Oldham ring 25 disposed on the upper part of the frame 3.

[0024] A first swing bearing 2d that receives a driving force is formed approximately in the center of the first swing scroll 2. The first swing bearing 2d is a cylindrical boss that protrudes from the surface (lower surface) of the first swing base plate 2c opposite to the surface on which the first swing scroll 2b is provided, toward the side (lower side) of the drive mechanism 37. A shaft hole 2f that communicates the space within the first swing bearing 2d with a central space SP1 (see FIG. 2) of the central cylindrical portion 1d of the first fixed scroll 1 is formed approximately in the center of the first swing base plate 2c.

[0025] 5, a shaft hole 2f is provided in the approximate center of the first oscillating base plate 2c, and a central cylindrical portion 1d having a central space SP1 is provided in the first fixed scroll 1, so that the drive shaft 7 can be configured to pass through the first compression mechanism portion 35 in the axial direction (direction of arrow Z). The central space SP1 and the shaft hole 2f also function as a flow path for refrigeration oil.

[0026] As shown in Fig. 1, the first rocking bearing 2d accommodates a portion of the drive shaft 7 in the axial direction (direction of arrow Z) (a first eccentric pin 7b, described later) with a small gap between the inner peripheral surface of the first rocking bearing 2d and the outer peripheral surface of the first eccentric pin 7b. In a configuration in which the first slider 41 is provided on the outer periphery of the first eccentric pin 7b as shown in Fig. 1, a small gap is formed between the inner peripheral surface of the first rocking bearing 2d and the outer peripheral surface of the first eccentric pin 7b. The first rocking bearing 2d, which makes an eccentric orbital movement due to the first eccentric pin 7b, is disposed in a cylindrical boss housing 3c formed in approximately the center of the frame 3.

[0027] The second compression mechanism 36 has a second fixed scroll 4 and a second orbiting scroll 5. In the second compression mechanism 36, the second orbiting scroll 5 is disposed on the side (lower side) of the first compression mechanism 35, and the second fixed scroll 4 is disposed on the side (upper side) of the high-pressure space 24. The second fixed scroll 4 has a second fixed base plate 4c and a second fixed scroll 4b, which is a spiral protrusion provided on one surface (lower surface) of the second fixed base plate 4c. The second orbiting scroll 5 has a second orbiting base plate 5c and a second orbiting scroll 5b, which is a spiral protrusion provided on one surface (upper surface) of the second orbiting base plate 5c. Here, the second fixed scroll 4b and the second orbiting scroll 5b each have a shape extending along a curve such as an involute or an algebraic spiral. The second fixed scroll 4 and the second orbiting scroll 5 are provided in a sealed container 11 with the second fixed scroll 4b and the second orbiting scroll 5b meshing with each other. A second compression chamber 13 is formed between the second fixed scroll 4b and the second orbiting scroll 5b, and the second compression chamber 13 moves radially inward and reduces in volume as the second orbiting scroll 5 eccentrically orbits.

[0028] The second fixed scroll 4 is fixed to the sealed container 11. A second discharge port 4a is formed in the center of the second fixed scroll 4, and discharges the compressed, high-pressure fluid. A second valve 17 made of a leaf spring is disposed at the outlet opening of the second discharge port 4a to cover the outlet opening and prevent backflow of the fluid. A second valve guard 16 is disposed above the second valve 17 to limit the lift amount of the second valve 17. In other words, as the second compression chamber 13 moves and its volume decreases, the fluid in the second compression chamber 13 is compressed to a set pressure (high pressure). When the second discharge port 4a opens to the second compression chamber 13, the second valve 17, which had been closing the second discharge port 4a, is lifted against its elastic force. The compressed fluid is then discharged from the second discharge port 4a into a high-pressure space 24 within a muffler 30 attached to the upper surface of the second fixed scroll 4, and then through the discharge pipe 9 to the outside of the sealed container 11. The space surrounded by the muffler 30 and the back surface of the second fixed scroll 4 forms a high-pressure space 24 that communicates with the second discharge port 4a.

[0029] In addition to the second discharge port 4a, the second fixed scroll 4 is formed with a sub-port 4d that communicates with the high-pressure space 24. A sub-port valve 19 made of a leaf spring is disposed at the outlet opening of the sub-port 4d to cover this outlet opening and prevent backflow of the fluid. A sub-port valve stopper 18 that limits the lift amount of the sub-port valve 19 is provided above the sub-port valve 19. In other words, when the fluid being compressed in the second compression chamber 13 is compressed up to a predetermined upper limit pressure, the sub-port valve 19 is lifted against its elastic force, and the compressed fluid is discharged from the sub-port 4d into the high-pressure space 24.

[0030] In Fig. 1, the second orbiting scroll 5 is disposed above the first fixed scroll 1 that constitutes the upper part of the first compression mechanism 35. As described above, the second orbiting scroll 5 revolves relative to the second fixed scroll 4 without rotating on its axis due to the second Oldham ring 26 disposed above the first fixed scroll 1.

[0031] A second oscillating bearing 5d that receives a driving force is formed in the approximate center of the second oscillating scroll 5. The second oscillating bearing 5d is a cylindrical boss that protrudes from the surface (lower surface) of the second oscillating base plate 5c opposite the surface on which the second oscillating scroll 5b is provided, toward the first compression mechanism 35 (lower side).

[0032] The upper end of the drive shaft 7 (particularly the second eccentric pin 7c, described later) is accommodated in a recess formed by the inner peripheral surface of the second rocking bearing 5d and the lower surface of the second rocking base plate 5c, with a small gap between the inner peripheral surface of the second rocking bearing 5d and the outer peripheral surface of the second eccentric pin 7c. In a configuration in which a second slider 42 is provided on the outer periphery of the second eccentric pin 7c as shown in FIG. 1, a small gap is formed between the inner peripheral surface of the second rocking bearing 5d and the outer peripheral surface of the second eccentric pin 7c. The second rocking bearing 5d, which eccentrically orbits due to the second eccentric pin 7c, is disposed in a central cylindrical portion 1d formed in approximately the center of the first fixed scroll 1. For this reason, hereinafter, the central cylindrical portion 1d of the first fixed scroll 1 may be referred to as a rocking bearing accommodation portion.

[0033] As shown in Fig. 5, the suction volume of the second compression mechanism 36 is configured to be smaller than the suction volume of the first compression mechanism 35. In Fig. 5, the tooth height H2 of the second fixed scroll 4b and the second oscillating scroll 5b is made smaller than the tooth height H2 of the first fixed scroll 1b and the first oscillating scroll 2b, thereby making the suction volume of the second compression mechanism 36 smaller than the suction volume of the first compression mechanism 35.

[0034] The method for adjusting the suction volumes of the first compression mechanism 35 and the second compression mechanism 36 is not limited to the above. Instead of adjusting the suction volumes by the tooth heights H1 and H2, adjustment may be made by, for example, the tooth thickness. In this case, the tooth thickness (i.e., radial width) of the second fixed scroll 4b and the second oscillating scroll 5b is configured to be greater than the tooth thickness of the first fixed scroll 1b and the first oscillating scroll 2b. Alternatively, the suction volumes may be adjusted by, for example, the tooth pitch. In this case, the tooth pitch (i.e., the radial tooth spacing) of the second fixed scroll 4b and the second oscillating scroll 5b is configured to be smaller than the tooth pitch of the first fixed scroll 1b and the first oscillating scroll 2b.

[0035] As shown in FIG. 1 , the drive mechanism 37 includes a stator 29 fixedly held within the sealed container 11, a rotor 28 rotatably disposed on the inner circumferential surface of the stator 29 and fixed to the drive shaft 7, and the drive shaft 7 housed longitudinally within the sealed container 11 and rotating integrally with the rotor 28. The stator 29 functions to rotate the rotor 28 when current is applied. The outer circumferential surface of the stator 29 is fixedly supported to the sealed container 11 by shrink fitting, spot welding, or the like. The rotor 28 is rotatably driven when current is applied to the stator 29, thereby rotating the drive shaft 7. The rotor 28 has a permanent magnet inside. The rotor 28 is fixed to the outer periphery of the drive shaft 7 and is held with a small gap between it and the stator 29.

[0036] The drive shaft 7 rotates in conjunction with the rotation of the rotor 28, thereby driving the first orbiting scroll 2 and the second orbiting scroll 5 to rotate. The drive shaft 7 has a central shaft portion 7a extending from the drive mechanism portion 37 toward the first compression mechanism portion 35, and two eccentric pins (a first eccentric pin 7b and a second eccentric pin 7c) that are provided on one side of the axial direction of the central shaft portion 7a (the upper side in FIG. 1 ) and are each eccentric with respect to the central shaft portion 7a.

[0037] The central shaft portion 7a is rotatably supported at its upper part by a main bearing 3a located in the center of the frame 3 that is arranged between the two compression mechanisms (first compression mechanism 35 and second compression mechanism 36) and the drive mechanism 37, and at its lower part by a sub-bearing 38 located in the center below the drive mechanism 37. In Fig. 1, a barrel-shaped crowning portion is formed in the portion of the central shaft portion 7a that is located within the main bearing 3a (the upper part of the central shaft portion 7a), and a sleeve 43 is provided on the outer periphery of this portion.

[0038] The first eccentric pin 7b is provided at the upper end of the central shaft portion 7a so as to be eccentric with respect to the central shaft portion 7a. The first eccentric pin 7b makes the first orbiting scroll 2 eccentric with respect to the central axis which is the center of rotation of the drive shaft 7. The first eccentric pin 7b is fitted into the first orbiting bearing portion 2d so that the outer peripheral surface of the first eccentric pin 7b can slide on the inner peripheral surface of the first orbiting bearing portion 2d of the first orbiting scroll 2. The first orbiting bearing portion 2d fitted with the first eccentric pin 7b moves eccentrically within the boss housing portion 3c of the frame 3.

[0039] The second eccentric pin 7c is provided at the upper end of the first eccentric pin 7b so as to be eccentric with respect to the central shaft portion 7a. The second eccentric pin 7c causes the second orbiting scroll 5 to be eccentric with respect to the central axis which is the center of rotation of the drive shaft 7. The second eccentric pin 7c is fitted into the second orbiting bearing portion 5d so that the outer circumferential surface of the second eccentric pin 7c can slide on the inner circumferential surface of the second orbiting bearing portion 5d of the second orbiting scroll 5. The second orbiting bearing portion 5d fitted with the second eccentric pin 7c moves eccentrically within the hole 1g (see FIG. 2) of the first fixed base plate 1c.

[0040] As shown in Fig. 1, in the scroll compressor 100 of the present disclosure, the first compression mechanism 35 and the second compression mechanism 36 are arranged so that the eccentric directions of the first orbiting scroll 2 and the second orbiting scroll 5 are opposite to each other in the rotational direction of the drive shaft 7. Specifically, the first orbiting scroll 2 and the second orbiting scroll 5 are arranged so that their eccentric directions are offset by approximately 180° (with a tolerance of ±several degrees). In Figs. 1 and 6, the eccentric direction of the first eccentric pin 7b relative to the central axis and the eccentric direction of the second eccentric pin 7c relative to the central axis are offset by approximately 180° (with a tolerance of ±several degrees) so that the first orbiting scroll 2 and the second orbiting scroll 5 perform eccentric orbital motion while being eccentric in opposite directions.

[0041] Specifically, when the drive shaft 7 is viewed from one side in the axial direction (above) as shown in Figure 6, when the center C1 of the first eccentric pin 7b is eccentric to the right with respect to the central axis C0, the center C2 of the second eccentric pin 7c is eccentric to the left with respect to the central axis C0. Then, when the drive shaft 7 rotates 90° in the rotation direction (the direction indicated by the arc-shaped arrow in Figure 6) from this state, when the center C1 of the first eccentric pin 7b is eccentric to the front side (downward in the figure), the center C2 of the second eccentric pin 7c is eccentric to the rear side (upward in the figure). In this way, the eccentric directions of the first eccentric pin 7b and the second eccentric pin 7c are always opposite to each other during operation.

[0042] The drive shaft 7 is formed by assembling multiple components. In the example shown in FIG. 1 , the drive shaft 7 is formed from a first shaft member 71 that forms the entire central shaft portion 7 a and the lower portion of the first eccentric pin 7 b, and a second shaft member 72 that is fixed to the first shaft member 71 and forms the upper portion of the first eccentric pin 7 b and the entire second eccentric pin 7 c. In the example shown in FIG. 1 , the upper end of the first shaft member 71 is disposed in a recess formed in the lower surface of the second shaft member 72. When manufacturing the scroll compressor 100 including the drive shaft 7 formed from multiple components, the first orbiting scroll 2 is disposed, and then the second shaft member 72 is fixed to the first shaft member 71 by shrink fitting or bolting. Then, the second orbiting scroll 5 is disposed.

[0043] 1, the drive shaft 7 is provided with a balancer 31 that offsets imbalance caused by the swinging motion of the first orbiting scroll 2 and the second orbiting scroll 5. In Fig. 1, the balancer 31 is provided in the axial direction of the drive shaft 7 (direction of arrow Z) between the drive mechanism unit 37 and the first orbiting scroll 2, which is closer to the drive mechanism unit 37 of the two orbiting scrolls.

[0044] 1, an oil supply passage 7d through which refrigerant oil flows is formed inside the drive shaft 7. An oil pump 21 is fixed to the underside of the drive shaft 7, and the rotational force of the drive shaft 7 can be transmitted to the oil pump 21. The oil pump 21 is, for example, a positive displacement pump, and supplies refrigerant oil stored in an oil sump 20 at the bottom of the sealed container 11 to the first compression mechanism 35 and the second compression mechanism 36 through the oil supply passage 7d inside the drive shaft 7 as the drive shaft 7 rotates. Specifically, refrigerant oil is supplied through the oil supply passage 7d to the first rocking bearing 2d, the main bearing 3a, the first thrust bearing 3s (see FIG. 5), the second rocking bearing 5d, the second thrust bearing 1s (see FIG. 5), and the like.

[0045] The oil supply passage 7d is provided, for example, along the central axis of the drive shaft 7 and extends in the axial direction (direction of arrow Z) and penetrates the drive shaft 7. In the example of FIG. 1, the oil supply passage 7d is formed so as to linearly penetrate the first eccentric pin 7b and the second eccentric pin 7c. In other words, even when the drive shaft 7 is configured by assembling the first shaft member 71 and the second shaft member 72, the portion of the oil supply passage 7d formed in the first shaft member 71 and the portion of the oil supply passage 7d formed in the second shaft member 72 are arranged so as to communicate with each other. Note that the configuration of the oil supply passage 7d is not limited to the above configuration. For example, the oil supply passage 7d may be configured to have a branch passage that branches midway in the extension direction and extends laterally.

[0046] In the following, the operation of the scroll compressor 100 will be described assuming that the fluid compressed in the scroll compressor 100 is a refrigerant. Fig. 7 is a vertical cross-sectional view showing the flow of refrigerant in the scroll compressor 100 of Fig. 1. The white arrows in Fig. 7 indicate the direction of refrigerant flow. Fig. 8 is a ph diagram of a refrigeration cycle when a scroll compressor of a comparative example is used. Fig. 9 is a ph diagram of a refrigeration cycle when the scroll compressor 100 according to the first embodiment is used.

[0047] When electricity is applied to a power supply terminal (not shown) provided on the sealed container 11, torque is generated in the stator 29 and the rotor 28, causing the drive shaft 7 to rotate. When the drive shaft 7 rotates, the first eccentric pin 7b and the second eccentric pin 7c, which constitute the upper part of the drive shaft 7 and are eccentric in opposite directions, cause the first orbiting scroll 2 and the second orbiting scroll 5 to perform eccentric orbital motion while maintaining a state in which their eccentric directions are 180° apart from each other.

[0048] As shown in Figure 7, when the drive shaft 7 is rotated by energization, refrigerant gas is drawn into the low-pressure space 22 in the sealed container 11 through the suction pipe 8. The refrigerant gas drawn into the low-pressure space 22 is then drawn into the first compression chamber 12 through a suction port (not shown) of the first compression mechanism 35. As the first orbiting scroll 2 eccentrically orbits, the first compression chamber 12 moves from the outer periphery toward the center, reducing its volume and compressing the refrigerant. The refrigerant gas compressed to a set pressure (intermediate pressure) in the first compression chamber 12 is discharged from the first discharge port 1a provided in the first fixed scroll 1 into the intermediate-pressure space 23 against the first valve 15.

[0049] The refrigerant gas discharged into the intermediate pressure space 23 is then taken into the second compression chamber 13 through a suction port (not shown) of the second compression mechanism 36 provided above the first compression mechanism 35. The second compression chamber 13 reduces its volume while moving from the outer periphery toward the center in accordance with the eccentric orbital motion of the second orbiting scroll 5, compressing the refrigerant. The refrigerant gas compressed to a set pressure (high pressure) in the second compression chamber 13 is discharged from the second discharge port 4 a provided in the second fixed scroll 4 against the second valve 17 into the high pressure space 24 and then discharged from the discharge pipe 9 to the outside of the sealed container 11.

[0050] 7 , in the scroll compressor 100 of the present disclosure, the first compression mechanism 35 and the second compression mechanism 36 are disposed on the same axial side (direction of arrow Z) of the drive mechanism 37, and the eccentric directions of the first orbiting scroll 2 and the second orbiting scroll 5 with respect to the central axis C0 are opposite to each other. As a result, the gas load and centrifugal force acting on the first orbiting scroll 2 are at least partially offset by the gas load and centrifugal force acting on the second orbiting scroll 5. This allows the bearing load to be reduced.

[0051] To facilitate understanding, the relationship between the forces acting on the first orbiting scroll 2 and the second orbiting scroll 5 will be described separately for the balance in the translational direction (left and right of the central axis C0 in FIG. 7 ) and the balance around the center of gravity of the drive shaft 7. In a configuration in which the first compression mechanism 35 and the second compression mechanism 36 are disposed axially above the drive mechanism 37 (particularly above the center of gravity of the drive shaft 7), when the eccentric directions of the first orbiting scroll 2 and the second orbiting scroll 5 are opposite to each other, the moments of the first orbiting scroll 2 and the second orbiting scroll 5 around the center of gravity take positive and negative values, respectively, and act in a direction that improves the balance around the center of gravity. Furthermore, when the eccentric directions of the first orbiting scroll 2 and the second orbiting scroll 5 are opposite to each other, the balance in the translational direction also improves.

[0052] Therefore, the first orbiting scroll 2 also functions as a balancer for the second orbiting scroll 5. As a result, in the scroll compressor 100 of the present disclosure, the mass of the balancer 31 can be reduced compared to conventional configurations, and the balancer 31 can be made more compact. In a conventional configuration in which the first compression mechanism 35 and the second compression mechanism 36 are disposed above and below the drive mechanism 37, and the eccentric directions of the first orbiting scroll 2 and the second orbiting scroll 5 are the same for balance around the center of gravity, the balancer 31 becomes larger for balance in the translational direction compared to the configuration of the present disclosure.

[0053] The weight ratio between the first orbiting scroll 2 and the second orbiting scroll 5 is close to each other. In the present disclosure, the first orbiting scroll 2 also serves as a balancer for the second orbiting scroll 5, so if the weights of the first orbiting scroll 2 and the second orbiting scroll 5 are precisely adjusted, the balancer 31 shown in Fig. 1 can be eliminated. In this way, the imbalance caused by the orbiting motion of the first orbiting scroll 2 and the second orbiting scroll 5 is reduced, thereby suppressing vibration and noise.

[0054] The fluid compressed by the first orbiting scroll 2 and the first fixed scroll 1 becomes at a pressure (intermediate pressure) intermediate between the pressure in the low-pressure space 22 (low pressure) and the pressure in the high-pressure space 24 (high pressure). Here, by providing a counterbore 1f in the upper surface of the first fixed base plate 1c and accommodating the first valve 15, the first valve 15 can be provided in the first compression mechanism 35 while avoiding interference with the second Oldham ring 26 and the second orbiting scroll 5 shown in FIG. 1. Furthermore, as shown in FIG. 1, the provision of the first valve 15 allows the first compression chamber 12 of the first compression mechanism 35 to be sealed by the first valve 15, so that the refrigerant in the first compression chamber 12 can be compressed to a set pressure and discharged into the intermediate-pressure space 23.

[0055] 7, in a configuration in which the second orbiting scroll 5 of the second compression mechanism 36 is provided above the first fixed scroll 1 of the first compression mechanism 35 and the first fixed scroll 1 functions as a frame, only one frame 3 and one main bearing 3a are required. Also, in a configuration in which a sleeve 43 is provided on the main bearing 3a as in FIG. 7, only one sleeve 43 is required. Therefore, the number of parts can be reduced compared to the conventional configuration.

[0056] Furthermore, when the second orbiting scroll 5 is provided above the first fixed scroll 1 as described above, it is possible to improve the performance of the scroll compressor 100. The reason for this will be explained below with reference to FIGS.

[0057] 8 and 9, the horizontal axis represents specific enthalpy h [kJ / kg], and the vertical axis represents pressure p [MPa]. In Fig. 8 and Fig. 9, point P1 represents the state of the refrigerant after heat exchange in the evaporator of the refrigeration cycle and immediately before being taken into the first compression chamber 12 of the scroll compressor. Point P2 represents the state of the refrigerant immediately after compression in the first compression chamber 12 is completed. Point P3 represents the state of the refrigerant after being discharged from the first compression chamber 12 to the intermediate-pressure space 23 and immediately before being taken into the second compression chamber 13. Point P4 represents the state of the refrigerant immediately after compression in the second compression chamber 13 is completed. Point P5 represents the state of the refrigerant after heat exchange in the condenser. Point P6 represents the state of the refrigerant after being decompressed by a pressure reducing means such as an expansion valve.

[0058] The scroll compressor of the comparative example, whose p-h diagram is shown in Figure 8, is a compressor configured in such a way that the first compression mechanism unit 35 and the second compression mechanism unit 36 ​​are arranged above and below the drive mechanism unit 37, as in the conventional compressor, and the eccentric directions of the first orbiting scroll 2 and the second orbiting scroll 5 are the same.

[0059] 7, in the scroll compressor 100 of the present disclosure, the intermediate-pressure space 23 is smaller than that of the comparative example. That is, the refrigerant brought to an intermediate pressure by the first compression mechanism 35 is drawn into the second compression chamber 13 of the second compression mechanism 36 immediately after being discharged from the first discharge port 1a. As a result, in the present disclosure, the pressure loss between the first compression chamber 12 and the second compression chamber 13 can be made smaller than in the conventional scroll compressor.

[0060] The distance between points P2 and P3 in the pH diagram (FIG. 9) of the present disclosure is shorter than the distance between points P2 and P3 in the pH diagram (FIG. 8) of the comparative example, which clearly shows the effect of reducing pressure loss in the intermediate pressure space 23. As described above, in the present disclosure, the pressure loss between the first compression chamber 12 and the second compression chamber 13 is smaller than in the conventional case, so that the refrigerant can be compressed more efficiently and the performance of the scroll compressor 100 is improved.

[0061] Fig. 10 is a vertical cross-sectional view showing the flow of refrigerating machine oil in the scroll compressor 100 of Fig. 1. The white arrows in Fig. 10 indicate the direction in which the refrigerating machine oil flows. The flow of the refrigerating machine oil will be described below with reference to Fig. 10.

[0062] When the drive shaft 7 rotates, the oil pump 21 pumps refrigeration oil from the oil reservoir 20 into the oil supply passage 7d in the drive shaft 7. The refrigeration oil pumped up into the oil supply passage 7d rises in the oil supply passage 7d and flows from the upper end of the drive shaft 7 (i.e., the upper end of the second eccentric pin 7c) into the second rocking bearing 5d, lubricating the second rocking bearing 5d. After lubricating the second rocking bearing 5d, part of the refrigeration oil flows radially outward to lubricate the second thrust bearing 1s, and the remaining part flows downward through the central space SP1 of the first fixed scroll 1 and the shaft hole 2f of the first rocking scroll 2 to lubricate the first rocking bearing 2d. After lubricating the first rocking bearing 2d, part of the refrigeration oil flows radially outward to lubricate the first thrust bearing 3s, and the remaining part flows downward to lubricate the main bearing 3a. After lubricating each part, the refrigeration oil flows downward and is stored in an oil reservoir 20.

[0063] The refrigerating machine oil is mixed with the refrigerant gas and taken into the first compression mechanism 35, passes through the first compression chamber 12, the intermediate pressure space 23, and the second compression chamber 13, and is discharged together with the refrigerant gas into the high-pressure space 24. The refrigerating machine oil discharged together with the refrigerant gas into the high-pressure space 24 is then discharged to the outside via the discharge pipe 9 together with the refrigerant gas.

[0064] In this manner, by providing the central space SP1 of the first fixed scroll 1 and the shaft hole 2f of the first orbiting scroll 2, the refrigeration oil discharged from the upper end of the drive shaft 7 (i.e., the upper end of the second eccentric pin 7c) can flow along the drive shaft 7. Therefore, the refrigeration oil can be supplied to the bearing structure on the second compression mechanism 36 side, and can also be easily supplied to the bearing structure on the first compression mechanism 35 side.

[0065] The configuration of the scroll compressor 100 is not limited to the above configuration. For example, in the first embodiment, the scroll compressor 100 is a two-stage scroll compressor having two compression mechanisms. However, the same effects can be obtained when the scroll compressor 100 is applied to a scroll compressor 100 having an even number of compression mechanisms. In this case, in a configuration in which, for example, four compression mechanisms are provided, a drive mechanism 37 is provided on one side (the lower side in FIG. 1 ) of the drive shaft 7, and a first compression mechanism 35, a second compression mechanism 36, a third compression mechanism, and a fourth compression mechanism are provided on the other side (the upper side in FIG. 1 ) of the drive shaft 7 in order from the side closest to the drive mechanism 37. The first orbiting scroll 2 of the first compression mechanism 35 and the second orbiting scroll 5 of the second compression mechanism 36 are arranged so that their eccentric directions are opposite to each other, and the third orbiting scroll of the third compression mechanism and the fourth orbiting scroll of the fourth compression mechanism are arranged so that their eccentric directions are opposite to each other. That is, an even number of compression mechanism units are paired in pairs, two from the side closest to the drive mechanism unit 37, so that the gas load and centrifugal force of each other can be canceled out. Also, in a configuration in which four compression mechanism units are provided, the compression mechanism units may be stacked without being spaced apart, so that the second fixed scroll 4 of the second compression mechanism unit 36 ​​also functions as a frame for the third compression mechanism unit, and the third fixed scroll of the third compression mechanism unit functions as a frame for the fourth compression mechanism unit.

[0066] Furthermore, for example, in the first embodiment, the first Oldham ring 25 and the second Oldham ring 26 each have a key, and the frame 3 and the first fixed scroll 1 each have a keyway (frame keyway 3e, first fixed keyway 1e), but the present invention is not limited to this. It is sufficient that each of the two orbiting scrolls has a function that allows it to revolve without rotating, and for example, the two Oldham rings each may have a keyway, and the frame 3 and the first fixed scroll 1 each may have a key.

[0067] In addition, in the first embodiment, an injection pipe is not provided in the sealed container 11, but an injection pipe may be provided. Fig. 11 is a vertical cross-sectional view showing a first modified example of the scroll compressor 100 of Fig. 1. Fig. 12 is a vertical cross-sectional view showing a second modified example of the scroll compressor 100 of Fig. 1.

[0068] 11 , in a scroll compressor 100 according to the first modification, an injection pipe 10 that connects an intermediate pressure space 23 to the outside is provided in a sealed container 11. Refrigerant is injected into the intermediate pressure space 23 from the outside through the injection pipe 10. In the first modification, the injection pipe 10 penetrates the upper part of the sealed container 11 and is provided from the high pressure space 24 to the intermediate pressure space 23.

[0069] In the second modification shown in FIG. 12, the injection pipe 10 penetrates the outer peripheral wall of the sealed container 11 and is provided directly in the intermediate pressure space 23 .

[0070] In the configuration in which the injection pipe 10 is provided as shown in Figures 11 and 12, the refrigerant gas compressed to a set pressure in the first compression chamber 12 and discharged from the first discharge port 1a to the intermediate pressure space 23 is mixed with the refrigerant flowing in from the injection pipe 10 and taken into the second compression chamber 13.

[0071] As described above, the scroll compressor 100 according to the first embodiment includes the sealed container 11 that forms an outer shell, the drive mechanism 37 that is disposed within the sealed container 11 and serves as a drive source, the first compression mechanism 35, and the second compression mechanism 36. The first compression mechanism 35 includes the first fixed scroll 1 that is fixed within the sealed container 11, and the first orbiting scroll 2 that forms the first compression chamber 12 between the first fixed scroll 1 and the first fixed scroll 2 that moves eccentrically relative to the first fixed scroll 1. The second compression mechanism 36 includes the second fixed scroll 4 that is fixed within the sealed container 11, and the second orbiting scroll 5 that forms the second compression chamber 13 between the second fixed scroll 4 and the second fixed scroll 4 and moves eccentrically relative to the second fixed scroll 4. The scroll compressor 100 also includes the drive shaft 7 that is rotated by the drive mechanism 37 and transmits the drive force of the drive mechanism 37 to the first orbiting scroll 2 and the second orbiting scroll 5. The first compression mechanism unit 35 and the second compression mechanism unit 36 ​​are arranged such that the first compression mechanism unit 35 is positioned between the drive mechanism unit 37 and the second compression mechanism unit 36 ​​in the axial direction, which is the direction along the drive shaft 7, and the eccentric directions of the first oscillating scroll 2 and the second oscillating scroll 5 are opposite in the rotation direction of the drive shaft 7.

[0072] In this way, in the scroll compressor 100, the two compression mechanism units are arranged on the same axial side of the drive mechanism unit 37, and the orbiting scrolls of the two compression mechanism units are arranged so that their eccentric directions are opposite to each other. As a result, the gas load and centrifugal force acting on the first orbiting scroll 2 act to cancel out the gas load and centrifugal force acting on the second orbiting scroll 5. Therefore, according to the present disclosure, in a scroll compressor 100 equipped with multiple compression mechanism units, it is possible to reduce the bearing load and make the balancer 31 more compact than before.

[0073] The drive shaft 7 also has a central shaft portion 7a extending from the drive mechanism portion 37 toward the first compression mechanism portion 35, a first eccentric pin 7b that is provided at the end of the central shaft portion 7a eccentrically with respect to the central shaft portion 7a and causes the first oscillating scroll 2 to move eccentrically, and a second eccentric pin 7c that is provided at the end of the first eccentric pin 7b eccentrically on the opposite side to the eccentric direction of the first eccentric pin 7b with respect to the central shaft portion 7a and causes the second oscillating scroll 5 to move eccentrically.

[0074] As a result, using the first eccentric pin 7b and the second eccentric pin 7c provided on the drive shaft 7, the first oscillating scroll 2 and the second oscillating scroll 5 can be arranged with a simple structure so that their eccentric directions are opposite to each other.

[0075] In addition, the drive shaft 7 is composed of a first shaft member 71 that constitutes the central shaft portion 7a and part of the first eccentric pin 7b, and a second shaft member 72 that is fixed to the first shaft member 71 and constitutes the remaining part of the first eccentric pin 7b and the second eccentric pin 7c.

[0076] This allows the first oscillating scroll 2 to be positioned, and then the first shaft member 71 and the second shaft member 72 to be assembled to form the drive shaft 7, and then the second oscillating scroll 5 to be positioned, making it easy to assemble the scroll compressor 100 even in a configuration in which the second eccentric pin 7c is provided at the end of the first eccentric pin 7b on the drive shaft 7.

[0077] Further, an oil supply passage 7d is formed in the drive shaft 7 to supply refrigerating machine oil to the first compression mechanism 35 and the second compression mechanism 36. The oil supply passage 7d is formed in the drive shaft 7 so as to linearly penetrate the first eccentric pin 7b and the second eccentric pin 7c.

[0078] As a result, the supply of refrigerating machine oil to the first compression mechanism 35 and the second compression mechanism 36 can be achieved with a simple oil supply passage 7d configuration.

[0079] The second orbiting scroll 5 has an orbiting bearing portion (second orbiting bearing portion 5d) that protrudes toward the first compression mechanism portion 35 and accommodates a portion of the axial direction of the drive shaft 7. The first fixed scroll 1 is formed with an orbiting bearing housing portion (central cylindrical portion 1d) in which the orbiting bearing portion is disposed.

[0080] As a result, the first fixed scroll 1 performs the frame function, and compared to the conventional system, only one frame 3, one sleeve 43, one main bearing 3a, etc. are required, thereby reducing the number of parts. Furthermore, by providing the second orbiting scroll 5 above the first fixed scroll 1, the distance between the first compression mechanism 35 and the second compression mechanism 36 is shorter than in the conventional system, thereby reducing pressure loss. Furthermore, if the drive shaft 7 is formed with an oil supply passage 7d so that refrigerant oil flows out from the upper end of the drive shaft 7, the refrigerant oil can lubricate the second orbiting bearing 5d of the second orbiting scroll 5 and then flow downward within the central cylindrical portion 1d of the first fixed scroll 1. Therefore, the refrigerant oil that lubricates the second orbiting bearing 5d can also lubricate the first thrust bearing 3s (see FIG. 5 ) and the side surface of the first orbiting scroll 2b.

[0081] The first fixed scroll 1 has a fixed base plate (first fixed base plate 1c) in which a discharge port (first discharge port 1a) is formed, and a counterbore 1f is formed in the surface of the fixed base plate on the side of the second compression mechanism 36. The first compression mechanism 35 is disposed in the counterbore 1f of the fixed base plate and has a discharge valve (first valve 15) that covers the discharge port.

[0082] This allows the first valve 15 to be installed without interference between the first fixed scroll 1 and the second orbiting scroll 5, the second Oldham ring 26, etc. By installing the first valve 15, the first compression chamber 12 is sealed by the first valve 15, and the fluid in the first compression mechanism 35 can be compressed to a set pressure (intermediate pressure) while suppressing pressure loss.

[0083] DESCRIPTION OF SYMBOLS 1 First fixed scroll, 1a First discharge port, 1b First fixed scroll, 1c First fixed base plate, 1d Central cylinder portion, 1e First fixed keyway, 1f Counterbore, 1g Hole, 1s Second thrust bearing portion, 2 First orbiting scroll, 2b First orbiting scroll, 2c First orbiting base plate, 2d First orbiting bearing portion, 2e First orbiting keyway, 2f Shaft hole, 3 Frame, 3a Main bearing, 3c Boss storage portion, 3e Frame keyway, 3s First thrust bearing portion, 4 Second fixed scroll, 4a Second discharge port, 4b Second fixed scroll, 4c Second fixed base plate, 4d Sub-port, 5 Second orbiting scroll, 5b Second orbiting scroll, 5c Second orbiting base plate, 5d Second orbiting bearing portion, 5e Second orbiting keyway, 7 Drive shaft, 7a Central shaft portion, 7b First eccentric pin, 7c Second eccentric pin, 7d Oil supply passage, 8 Intake pipe, 9 Discharge pipe, 10 Injection pipe, 11 Sealed container, 12 First compression chamber, 13 Second compression chamber, 14 First valve stopper, 15 First valve, 16 Second valve stopper, 17 Second valve, 18 Sub-port valve stopper, 19 Sub-port valve, 20 Oil reservoir, 21 Oil pump, 22 Low pressure space, 23 Intermediate pressure space, 24 High pressure space, 25 First Oldham ring, 26 Second Oldham ring, 28 Rotor, 29 Stator, 30 Muffler, 31 Balancer, 35 First compression mechanism, 36 Second compression mechanism, 37 Drive mechanism, 38 Sub-receiving portion, 41 First slider, 42 Second slider, 43 Sleeve, 71 First shaft member, 72 Second shaft member, 100 Scroll compressor, C0 central axis, C1 center, C2 center, H1 tooth height, H2 tooth height, SP1 central space, Z arrow, h specific enthalpy, p pressure.

Claims

a first compression mechanism unit having a first fixed scroll fixed within the sealed container and a first oscillating scroll which forms a first compression chamber between the first fixed scroll and performs eccentric motion with respect to the first fixed scroll; a second compression mechanism unit having a second fixed scroll fixed within the sealed container and a second oscillating scroll which forms a second compression chamber between the second fixed scroll and performs eccentric motion with respect to the second fixed scroll; and a drive shaft which is rotated by the drive mechanism unit and transmits the drive force of the drive mechanism unit to the first oscillating scroll and the second oscillating scroll, wherein the first compression mechanism unit and the second compression mechanism unit are disposed between the drive mechanism unit and the second compression mechanism unit in an axial direction which is along the drive shaft, and are disposed such that the eccentric directions of the first oscillating scroll and the second oscillating scroll are opposite to each other in the rotation direction of the drive shaft.

2. The scroll compressor as described in claim 1, wherein the drive shaft has: a central shaft portion extending from the drive mechanism portion toward the first compression mechanism portion; a first eccentric pin provided at an end of the central shaft portion eccentrically with respect to the central shaft portion and causing the first oscillating scroll to perform eccentric motion; and a second eccentric pin provided at an end of the first eccentric pin eccentrically on the opposite side to the eccentric direction of the first eccentric pin with respect to the central shaft portion and causing the second oscillating scroll to perform eccentric motion.

3. The scroll compressor according to claim 2, wherein the drive shaft is composed of a first shaft member constituting the central shaft portion and a part of the first eccentric pin, and a second shaft member fixed to the first shaft member and constituting the remaining part of the first eccentric pin and the second eccentric pin.

4. A scroll compressor as described in claim 2 or 3, wherein an oil supply passage is formed in the drive shaft for supplying refrigeration oil to the first compression mechanism section and the second compression mechanism section, and the oil supply passage is formed so as to linearly penetrate the first eccentric pin and the second eccentric pin on the drive shaft.

5. A scroll compressor as claimed in any one of claims 1 to 4, wherein the second oscillating scroll has an oscillating bearing portion that protrudes towards the first compression mechanism portion and accommodates a portion of the axial direction of the drive shaft, and the first fixed scroll is formed with an oscillating bearing housing portion in which the oscillating bearing portion is arranged.

6. A scroll compressor as claimed in any one of claims 1 to 5, wherein the first fixed scroll has a fixed base plate in which a discharge port is formed, a countersink is formed in the surface of the fixed base plate facing the second compression mechanism, and the first compression mechanism is disposed in the countersink of the fixed base plate and has a discharge valve covering the discharge port.

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