Scroll compressor

Abstract

An air supply passage (51) is formed in an orbiting scroll (26) and has a first end that opens at the leading end of an orbiting spiral wall (26b) to allow connection to a compression chamber (27) and a second end connecting to a back pressure chamber (50). An oil return passage (60) has a first passage (61) and a second passage (62). The first passage (61) is formed in a fixed scroll (25) and has a first end connecting to an oil reservoir (42) and a second end opening at a portion of the fixed scroll (25) that can slide against an orbiting base plate (26a). The second passage (62) is formed in the orbiting scroll (26). The second passage (62) has a first end that opens at a portion of the orbiting base plate (26a) that can slide against the fixed scroll (25) to allow connection to the first passage (61) via a gap between the fixed scroll (25) and the orbiting scroll (26) and a second end connecting to the back pressure chamber (50).

Description

Scroll Compressor

[0001] The present invention relates to a scroll compressor.

[0002] A scroll compressor includes a housing, a rotating shaft, a fixed scroll, and an orbiting scroll. The rotating shaft is rotatably supported by the housing. The fixed scroll is fixed to the housing. The fixed scroll has a fixed base plate and a fixed spiral wall. The fixed spiral wall stands upright from the fixed base plate. The orbiting scroll has an orbiting base plate and an orbiting spiral wall. The orbiting base plate faces the fixed base plate. The orbiting spiral wall stands upright from the orbiting base plate toward the fixed base plate. The orbiting spiral wall meshes with the fixed spiral wall. The orbiting scroll revolves relative to the fixed scroll as the rotating shaft rotates.

[0003] The scroll compressor has a suction pressure region. Refrigerant gas containing oil is drawn into the suction pressure region. The scroll compressor has a compression chamber, a discharge chamber, an oil storage chamber, and a back pressure chamber. The compression chamber is partitioned by a fixed base plate, a fixed spiral wall, an orbiting base plate, and an orbiting spiral wall. The compression chamber compresses the refrigerant gas drawn into the suction pressure region. The refrigerant gas compressed in the compression chamber is discharged into the discharge chamber. The oil storage chamber stores oil separated from the refrigerant gas discharged into the discharge chamber. Refrigerant gas is introduced into the back pressure chamber to urge the orbiting scroll toward the fixed scroll.

[0004] In such scroll compressors, a portion of the refrigerant gas compressed in the compression chamber is supplied from the compression chamber to the back pressure chamber through an air supply passage, as described in, for example, Patent Document 1. This increases the pressure in the back pressure chamber, constantly biasing the orbiting scroll toward the fixed scroll. As a result, refrigerant gas is less likely to leak from the compression chamber, improving the compression efficiency of the scroll compressor.

[0005] Furthermore, the scroll compressor returns oil stored in the oil reservoir to at least one of the back pressure chamber and the suction pressure region using an oil return passage, as described in Patent Document 1. This allows the oil to lubricate sliding parts arranged in the back pressure chamber and the oil to lubricate sliding parts arranged in the suction pressure region, thereby improving the durability of the scroll compressor.

[0006] JP 2011-64189 A

[0007] However, for example, if the oil return passage has a fixed throttle, it is difficult to control the flow rate of oil returned from the oil reservoir to at least one of the back pressure chamber and the suction pressure region through the oil return passage. Therefore, for example, if the flow rate of oil returned from the oil reservoir to at least one of the back pressure chamber and the suction pressure region through the oil return passage is too high, the oil may interfere with the movement of the sliding parts. The oil interfering with the movement of the sliding parts causes power loss in the scroll compressor.

[0008] On the other hand, it is conceivable to provide a flow control valve in the oil return passage to control the flow rate of oil returned from the oil reservoir to at least one of the back pressure chamber and the suction pressure region through the oil return passage. However, providing a flow control valve in the oil return passage is undesirable because it increases the number of parts in the scroll compressor. Therefore, it is desirable to reduce the power loss of the scroll compressor while suppressing the increase in the number of parts in the scroll compressor.

[0009] A scroll compressor that solves the above problem includes a housing, a rotating shaft rotatably supported by the housing, a fixed scroll having a fixed base plate and a fixed spiral wall standing from the fixed base plate and fixed to the housing, an orbiting base plate facing the fixed base plate, and an orbiting spiral wall standing from the orbiting base plate toward the fixed base plate and engaging with the fixed spiral wall, the orbiting scroll revolving relative to the fixed scroll as the rotating shaft rotates, a suction pressure region into which refrigerant gas containing oil is sucked, and a compressor including the fixed base plate, the fixed base plate, and the fixed scroll. a compression chamber defined by the spiral wall, the orbiting base plate, and the orbiting spiral wall, which compresses refrigerant gas drawn into the suction pressure region; a discharge chamber into which the refrigerant gas compressed in the compression chamber is discharged; an oil storage chamber in which oil separated from the refrigerant gas discharged into the discharge chamber is stored; a back pressure chamber into which refrigerant gas for urging the orbiting scroll toward the fixed scroll is introduced; an air supply passage which supplies a portion of the refrigerant gas compressed in the compression chamber to the back pressure chamber; and an oil return passage which returns oil stored in the oil storage chamber to at least one of the back pressure chamber and the suction pressure region. the supply passage is formed in the orbiting scroll, and has a first end that opens at one of a tip of the orbiting spiral wall and a portion of the orbiting base plate that can slide against the tip of the fixed spiral wall, and can communicate with the compression chamber, and a second end that communicates with the back pressure chamber; the oil return passage is formed in the fixed scroll, and has a first end that communicates with the oil storage chamber, and a second end that opens at a portion of the fixed scroll that can slide against the orbiting base plate, and is formed in the orbiting scroll; and a second passage having a first end that opens at a portion of the orbiting base plate that can slide against the fixed scroll and can communicate with the first passage through a gap between the fixed scroll and the orbiting scroll, and a second end that communicates with at least one of the back pressure chamber and the suction pressure region, or the oil return passage is formed in the fixed scroll and has a first end that communicates with the oil reservoir chamber and a second end that opens at a portion of the fixed base plate that can slide against the tip of the orbiting spiral wall, and is formed in the orbiting scroll,a second passage having a first end that opens to the tip of the orbiting scroll and that can communicate with the first passage through a gap between the fixed scroll and the orbiting scroll, and a second end that communicates with at least one of the back pressure chamber and the suction pressure region;

[0010] According to this configuration, for example, when the pressure in the back pressure chamber decreases, the biasing force biasing the orbiting scroll toward the fixed scroll decreases, causing the tip of the orbiting spiral wall and the portion of the orbiting base plate that can slide against the tip of the fixed spiral wall to move away from the fixed scroll. As a result, a portion of the refrigerant gas compressed in the compression chamber is supplied to the back pressure chamber through the supply passage, increasing the pressure in the back pressure chamber. Therefore, the orbiting scroll is biased toward the fixed scroll, making it less likely that refrigerant gas will leak from the compression chamber. As a result, the compression efficiency of the scroll compressor is improved. Furthermore, when the pressure in the back pressure chamber decreases, the portion of the orbiting base plate that can slide against the fixed scroll and the tip of the orbiting spiral wall move away from the fixed scroll. As a result, in the oil return passage, oil flowing from the oil reservoir chamber through the first passage flows into the second passage through the gap between the fixed scroll and the orbiting scroll. The oil that has flowed into the second passage is then returned to at least one of the back pressure chamber and the suction pressure region. In this way, when the pressure in the back pressure chamber drops, oil is returned from the oil reservoir to at least one of the back pressure chamber and the suction pressure region through the oil return passage. This prevents the flow rate of oil returned from the oil reservoir to at least one of the back pressure chamber and the suction pressure region through the oil return passage from becoming too high. This avoids the problem of oil returning too high to at least one of the back pressure chamber and the suction pressure region through the oil return passage, which would interfere with the movement of sliding components constituting the scroll compressor. This reduces power loss in the scroll compressor. In this way, there is no need to provide a flow control valve in the oil return passage to control the flow rate of oil returned from the oil reservoir to at least one of the back pressure chamber and the suction pressure region through the oil return passage. This reduces the number of parts in the scroll compressor. As a result, power loss in the scroll compressor can be reduced while minimizing the number of parts in the scroll compressor.

[0011] The scroll compressor may further include an eccentric shaft that protrudes toward the orbiting scroll from an end face of the rotating shaft at a position eccentric with respect to the axis of the rotating shaft, a bearing that supports the orbiting scroll so that the orbiting scroll can rotate relative to the eccentric shaft is disposed within the back pressure chamber, and a second end of the second passage communicates with the back pressure chamber. In this configuration, oil returned from the oil storage chamber through the oil return passage to the back pressure chamber contributes to lubrication of the bearing, thereby improving durability of the scroll compressor.

[0012] In the scroll compressor, a first end of the second passage may be opened at a portion of the orbiting base plate that is in sliding contact with the fixed scroll, and the second passage may penetrate the orbiting base plate in a thickness direction of the orbiting base plate. This configuration is simple in terms of forming a second passage in the orbiting scroll, the second end of which is in communication with the back pressure chamber.

[0013] In the above scroll-type compressor, the second end of the first passage is preferably located at the center of an orbital locus caused by the orbital motion of the orbiting scroll at the first end of the second passage, and is provided with a sealing member that is annular and surrounds the orbital locus and seals between the fixed scroll and the orbiting scroll.

[0014] This configuration prevents, for example, refrigerant gas from the compression chamber from flowing into the oil return passageway through the gap between the fixed scroll and the orbiting scroll. Also, the seal member prevents oil flowing through the oil return passageway from leaking into the suction pressure region through the gap between the fixed scroll and the orbiting scroll. This prevents a decrease in the flow rate of oil returned from the oil storage chamber to the back pressure chamber through the oil return passageway.

[0015] In the scroll compressor, the oil return passage may be located radially outward of the rotary shaft relative to the air supply passage. A configuration in which the oil return passage is located radially outward of the rotary shaft relative to the air supply passage is preferable in terms of configuring the oil return passage.

[0016] According to the present invention, it is possible to suppress the power loss of the scroll compressor while suppressing an increase in the number of parts of the scroll compressor.

[0017] Fig. 1 is a cross-sectional view of a scroll compressor according to an embodiment, Fig. 2 is an enlarged cross-sectional view of a portion of the scroll compressor, and Fig. 3 is a cross-sectional view taken along line 3-3 in Fig. 2.

[0018] An embodiment of a scroll compressor will be described below with reference to FIGS. 1 to 3. The scroll compressor of this embodiment is used, for example, in a vehicle air conditioning system. <Basic Configuration of Scroll Compressor> As shown in FIG. 1, the scroll compressor 10 includes a cylindrical housing 11. The housing 11 has a motor housing 12, a support housing 13, and a discharge housing 14. The motor housing 12, the support housing 13, and the discharge housing 14 are made of a metal material. The motor housing 12, the support housing 13, and the discharge housing 14 are made of, for example, aluminum. The scroll compressor 10 also includes a rotating shaft 15. The rotating shaft 15 is accommodated in the housing 11.

[0019] The motor housing 12 has a plate-shaped end wall 12a and a cylindrical peripheral wall 12b. The peripheral wall 12b extends cylindrically from the outer periphery of the end wall 12a. The axial direction of the peripheral wall 12b coincides with the axial direction of the rotary shaft 15. The motor housing 12 has a plurality of female threaded holes 12c. Each female threaded hole 12c is formed at an open end of the peripheral wall 12b. Note that FIG. 1 shows only one female threaded hole 12c for ease of explanation. The motor housing 12 also has an intake port 12h. The intake port 12h draws in refrigerant gas. The intake port 12h is formed in a portion of the peripheral wall 12b that is located on the end wall 12a side. The intake port 12h connects the inside and outside of the motor housing 12.

[0020] The motor housing 12 has a cylindrical boss portion 12d. The boss portion 12d protrudes from the center of the inner surface of the end wall 12a. A first end, which is one axial end of the rotary shaft 15, is inserted into the boss portion 12d. The scroll compressor 10 is equipped with a bearing 16. The bearing 16 is, for example, a rolling bearing. The bearing 16 is provided between the inner circumferential surface of the boss portion 12d and the outer circumferential surface of the first end of the rotary shaft 15. The first end of the rotary shaft 15 is rotatably supported by the motor housing 12 via the bearing 16.

[0021] The journal housing 13 has a plate-shaped end wall 17 and a cylindrical peripheral wall 18. The peripheral wall 18 extends cylindrically from the outer periphery of the end wall 17. The axial direction of the peripheral wall 18 coincides with the axial direction of the rotary shaft 15. The journal housing 13 also has an annular flange wall 19. The flange wall 19 extends radially outward from the end of the outer periphery of the peripheral wall 18 opposite the end wall 17.

[0022] The support housing 13 has a circular insertion hole 17a. The insertion hole 17a is formed in the center of the end wall 17. The insertion hole 17a penetrates the end wall 17 in the thickness direction. The rotary shaft 15 is inserted through the insertion hole 17a. An end face 15e located on the second end side, which is the other end in the axial direction of the rotary shaft 15, is located inside the peripheral wall 18.

[0023] The scroll compressor 10 includes a bearing 21. The bearing 21 is, for example, a rolling bearing. The bearing 21 is provided between the inner circumferential surface of the peripheral wall 18 and the outer circumferential surface of the rotating shaft 15. The rotating shaft 15 is rotatably supported by the support housing 13 via the bearing 21. Therefore, the support housing 13 rotatably supports the rotating shaft 15. In this manner, the rotating shaft 15 is rotatably supported by the housing 11.

[0024] The journal support housing 13 has a plurality of bolt insertion holes 19a. Each bolt insertion hole 19a is formed on the outer periphery of the flange wall 19. Each bolt insertion hole 19a penetrates the flange wall 19 in the thickness direction. Each bolt insertion hole 19a in the flange wall 19 communicates with each of the female threaded holes 12c in the motor housing 12. For ease of explanation, only one bolt insertion hole 19a is shown in FIG. 1 .

[0025] The scroll compressor 10 has a motor chamber 20. The motor chamber 20 is defined by the motor housing 12 and the support housing 13. The motor housing 12 defines the motor chamber 20 together with the support housing 13. In this manner, the motor chamber 20 is formed within the housing 11. The motor chamber 20 is connected to the suction port 12h. Refrigerant gas is drawn into the motor chamber 20 from the suction port 12h. The refrigerant gas in the motor chamber 20 contains oil. Therefore, the motor chamber 20 is a suction pressure region into which the refrigerant gas containing oil is drawn.

[0026] The scroll compressor 10 includes a motor 22. The motor 22 is housed in the motor chamber 20. The motor 22 includes a cylindrical stator 23 and a cylindrical rotor 24. The rotor 24 is disposed inside the stator 23. The rotor 24 rotates integrally with the rotary shaft 15. The stator 23 surrounds the rotor 24. The rotor 24 includes a rotor core 24a fixed to the rotary shaft 15 and a plurality of permanent magnets (not shown) provided in the rotor core 24a.

[0027] The stator 23 has a cylindrical stator core 23a and a motor coil 23b. The stator core 23a is fixed to the inner circumferential surface of the peripheral wall 12b of the motor housing 12. The motor coil 23b is wound around the stator core 23a. Electric power controlled by an inverter (not shown) is supplied to the motor coil 23b, causing the rotor 24 to rotate. This causes the rotating shaft 15 to rotate integrally with the rotor 24. Therefore, the motor 22 rotates the rotating shaft 15.

[0028] The scroll compressor 10 includes a compression mechanism C1. The compression mechanism C1 has a fixed scroll 25 and an orbiting scroll 26. Therefore, the scroll compressor 10 includes the fixed scroll 25 and the orbiting scroll 26. The compression mechanism C1 is of a scroll type. The orbiting scroll 26 revolves around the fixed scroll 25 as the rotary shaft 15 rotates.

[0029] The fixed scroll 25 has a fixed base plate 25a and a fixed spiral wall 25b. The fixed base plate 25a is disk-shaped. The thickness direction of the fixed base plate 25a coincides with the axial direction of the rotary shaft 15. A discharge port 25h is formed in the center of the fixed base plate 25a. The discharge port 25h is a circular hole-shaped hole. The discharge port 25h penetrates the fixed base plate 25a in the thickness direction. The fixed spiral wall 25b stands upright from the fixed base plate 25a. The fixed scroll 25 also has an outer circumferential wall 25c. The outer circumferential wall 25c stands upright from the outer periphery of the fixed base plate 25a. The outer circumferential wall 25c surrounds the fixed spiral wall 25b.

[0030] A recess 25e is formed in an end surface 25d of the outer peripheral wall 25c. The recess 25e is a circular hole. A bottom surface 25f of the recess 25e is flat. The bottom surface 25f of the recess 25e is located on the same plane as the tip surface of the fixed spiral wall 25b.

[0031] The scroll compressor 10 includes a valve mechanism 25v. The valve mechanism 25v is attached to a fixed base plate 25a. The valve mechanism 25v is configured to be able to open and close a discharge port 25h.

[0032] The orbiting scroll 26 has an orbiting base plate 26a and an orbiting spiral wall 26b. The orbiting base plate 26a is disk-shaped. The thickness direction of the orbiting base plate 26a coincides with the axial direction of the rotation shaft 15. The orbiting base plate 26a faces the fixed base plate 25a. The orbiting spiral wall 26b rises from the orbiting base plate 26a toward the fixed base plate 25a. The orbiting spiral wall 26b meshes with the fixed spiral wall 25b. The orbiting base plate 26a of the orbiting scroll 26 is located inside the recess 25e of the outer peripheral wall 25c. The orbiting scroll 26 revolves with the orbiting base plate 26a located inside the recess 25e of the outer peripheral wall 25c. The orbiting base plate 26a can slide against the tip surface of the fixed spiral wall 25b. Therefore, the orbiting base plate 26a has a portion that can slide against the tip of the fixed spiral wall 25b. A portion of the orbiting base plate 26a located radially outward of the rotating shaft 15 relative to the orbiting spiral wall 26b can slide against the bottom surface 25f of the recess 25e. Therefore, the portion of the orbiting base plate 26a located radially outward of the rotating shaft 15 relative to the orbiting spiral wall 26b is a portion of the orbiting base plate 26a that can slide against the fixed scroll 25. Furthermore, the bottom surface 25f of the recess 25e is a portion of the fixed scroll 25 that can slide against the orbiting base plate 26a. The tip surface of the orbiting spiral wall 26b can slide against the fixed base plate 25a. Therefore, the fixed base plate 25a has a portion that can slide against the tip of the orbiting spiral wall 26b.

[0033] The scroll compressor 10 includes a compression chamber 27. The compression chamber 27 is defined by a fixed base plate 25a, a fixed spiral wall 25b, an orbiting base plate 26a, and an orbiting spiral wall 26b. Therefore, the compression chamber 27 is defined between the fixed scroll 25 and the orbiting scroll 26. The compression chamber 27 takes in and compresses the refrigerant gas sucked into the motor chamber 20. Therefore, the compression chamber 27 compresses the refrigerant gas sucked into the suction pressure region.

[0034] The orbiting base plate 26a has a cylindrical boss portion 26c. The boss portion 26c protrudes from an end face 26e of the orbiting base plate 26a opposite the fixed base plate 25a. The axial direction of the boss portion 26c coincides with the axial direction of the rotary shaft 15. The orbiting base plate 26a also has a plurality of grooves 26d. The grooves 26d are each formed around the boss portion 26c on the end face 26e of the orbiting base plate 26a. The grooves 26d are arranged at predetermined intervals in the circumferential direction of the rotary shaft 15. Note that, for convenience of explanation, only one groove 26d is shown in FIG. 1 . An annular ring member 28 is fitted into each groove 26d. A pin 29 is inserted into each ring member 28. Each pin 29 protrudes from the end face 13e of the journal housing 13 on the orbiting scroll 26 side.

[0035] The scroll compressor 10 includes an elastic plate 30. The elastic plate 30 is annular. The elastic plate 30 is sandwiched between an end surface 13e of the support housing 13 and an end surface 25d of the outer circumferential wall 25c. The elastic plate 30 constantly biases the orbiting scroll 26 toward the fixed scroll 25.

[0036] The scroll compressor 10 includes an eccentric shaft 31. The eccentric shaft 31 protrudes toward the orbiting scroll 26 from a position on the end face 15e of the rotary shaft 15 that is eccentric with respect to the axis L1 of the rotary shaft 15. The eccentric shaft 31 is formed integrally with the rotary shaft 15. The axial direction of the eccentric shaft 31 coincides with the axial direction of the rotary shaft 15. The eccentric shaft 31 is inserted into the boss portion 26c.

[0037] The scroll compressor 10 includes a balance weight 32 and a bushing 33. The bushing 33 is fitted onto the outer peripheral surface of the eccentric shaft 31. The balance weight 32 is integrated with the bushing 33. The balance weight 32 is formed integrally with the bushing 33. The balance weight 32 is housed within the peripheral wall 18 of the support housing 13. The orbiting scroll 26 is supported on the eccentric shaft 31 via the bushing 33 and a rolling bearing 34 so as to be rotatable relative to the eccentric shaft 31. Therefore, the rolling bearing 34 is a bearing that supports the orbiting scroll 26 so as to be rotatable relative to the eccentric shaft 31.

[0038] The rotation of the rotating shaft 15 is transmitted to the orbiting scroll 26 via the eccentric shaft 31, the bushing 33, and the rolling bearing 34. This causes the orbiting scroll 26 to rotate on its axis. Contact between each pin 29 and the inner circumferential surface of each ring member 28 prevents the orbiting scroll 26 from rotating on its axis, allowing only the orbiting scroll 26 to revolve. As a result, the orbiting scroll 26 revolves while the orbiting spiral wall 26b contacts the fixed spiral wall 25b. As the orbiting scroll 26 revolves, the volume of the compression chamber 27 decreases, compressing the refrigerant gas in the compression chamber 27. The balance weight 32 offsets the centrifugal force acting on the orbiting scroll 26 as it revolves. This reduces the amount of imbalance in the orbiting scroll 26.

[0039] The discharge housing 14 has a plate-shaped end wall 14a and a cylindrical peripheral wall 14b. The peripheral wall 14b extends cylindrically from the outer periphery of the end wall 14a. The axial direction of the peripheral wall 14b coincides with the axial direction of the rotary shaft 15. The peripheral wall 14b surrounds the fixed scroll 25. Therefore, the fixed scroll 25 is accommodated within the housing 11.

[0040] The discharge housing 14 has a plurality of bolt insertion holes 14c. Each bolt insertion hole 14c is formed in the peripheral wall 14b. For convenience of explanation, only one bolt insertion hole 14c is shown in Fig. 1. Each bolt insertion hole 14c communicates with a corresponding bolt insertion hole 19a in the flange wall 19.

[0041] The bolts B1 passing through each bolt insertion hole 14c pass through each bolt insertion hole 19a in the flange wall 19 and are threaded into each female threaded hole 12c of the motor housing 12. This connects the journal housing 13 to the peripheral wall 12b of the motor housing 12, and the discharge housing 14 to the flange wall 19 of the journal housing 13. Therefore, the motor housing 12, journal housing 13, and discharge housing 14 are arranged in this order in the axial direction of the rotating shaft 15. The fixed scroll 25 is sandwiched between the end wall 14a of the discharge housing 14 and the journal housing 13. In this way, the fixed scroll 25 is fixed to the housing 11. The discharge housing 14 is connected to the fixed scroll 25.

[0042] The scroll compressor 10 includes a suction passage 35. The suction passage 35 has a first groove 36, a first hole 37, and a second groove 38. A plurality of first grooves 36 are formed in the inner circumferential surface of the peripheral wall 12b of the motor housing 12. Each first groove 36 opens at an open end of the peripheral wall 12b. A plurality of first holes 37 are formed in the outer circumferential portion of the flange wall 19 of the support housing 13. Each first hole 37 penetrates the flange wall 19 in the thickness direction. Each first hole 37 communicates with a corresponding first groove 36. A plurality of second grooves 38 are formed in the inner circumferential surface of the peripheral wall 14b of the discharge housing 14. Each second groove 38 communicates with a corresponding first hole 37.

[0043] An intake port 39 is formed in the outer peripheral wall 25c of the fixed scroll 25. The intake port 39 penetrates the outer peripheral wall 25c in the thickness direction. The intake port 39 communicates with the second groove 38. The intake port 39 communicates with the outermost peripheral portion of the compression chamber 27.

[0044] The refrigerant in the motor chamber 20 passes through the first groove 36, the first hole 37, the second groove 38, and the suction port 39 and is drawn into the compression chamber 27. The suction passage 35, which is formed by the first groove 36, the first hole 37, and the second groove 38, and the suction port 39, form a suction pressure region through which refrigerant gas flows to be drawn into the compression chamber 27. The refrigerant gas drawn into the compression chamber 27 is compressed within the compression chamber 27 by the orbital motion of the orbiting scroll 26. In this way, the compression mechanism C1 compresses the refrigerant drawn into the housing 11.

[0045] The scroll compressor 10 includes a plate-shaped gasket 40. The gasket 40 is a thin metal plate. The gasket 40 is annular. The gasket 40 seals the gap between the end wall 14a of the discharge housing 14 and the fixed base plate 25a.

[0046] The scroll compressor 10 includes a discharge chamber 41. The discharge chamber 41 is formed between the end wall 14a of the discharge housing 14 and the fixed base plate 25a of the fixed scroll 25. The discharge chamber 41 communicates with the discharge port 25h. Refrigerant gas compressed in the compression chamber 27 is discharged into the discharge chamber 41 through the discharge port 25h.

[0047] The scroll compressor 10 includes an oil reservoir 42. The oil reservoir 42 is formed between the end wall 14a of the discharge housing 14 and the fixed base plate 25a of the fixed scroll 25. The oil reservoir 42 is located vertically below the discharge chamber 41. Therefore, the scroll compressor 10 is mounted on a vehicle so that the oil reservoir 42 is located vertically below the discharge chamber 41. The oil reservoir 42 stores oil separated from the refrigerant gas discharged into the discharge chamber 41. A gasket 40 seals the discharge chamber 41 and the oil reservoir 42.

[0048] The scroll compressor 10 includes an oil separation chamber 43. The oil separation chamber 43 is formed inside the discharge housing 14. The oil separation chamber 43 is formed inside an elongated cylindrical outer cylinder 44 that is part of the end wall 14a of the discharge housing 14. A first end of the outer cylinder 44 forms a discharge port 45 that discharges refrigerant gas to the outside. The discharge port 45 communicates with the oil separation chamber 43. A second end of the outer cylinder 44 communicates with the oil reservoir chamber 42. Therefore, the oil separation chamber 43 communicates with the oil reservoir chamber 42 via the outer cylinder 44.

[0049] An inner cylinder 46 is fitted into the oil separation chamber 43. The axial direction of the inner cylinder 46 coincides with the radial direction of the rotating shaft 15. A first end of the inner cylinder 46 communicates with the discharge port 45. A second end of the inner cylinder 46 communicates with the oil separation chamber 43 on the side opposite the discharge port 45. An introduction hole 47 is formed in the outer cylinder 44. The introduction hole 47 communicates between the discharge chamber 41 and the oil separation chamber 43. The introduction hole 47 introduces the refrigerant gas discharged into the discharge chamber 41 into the oil separation chamber 43.

[0050] The refrigerant gas compressed in the compression chamber 27 and discharged into the discharge chamber 41 through the discharge port 25h is introduced into the oil separation chamber 43 through the inlet hole 47. The refrigerant gas introduced into the oil separation chamber 43 swirls around the inner cylinder 46. This applies centrifugal force to the oil contained in the refrigerant gas, causing the oil to be separated from the refrigerant gas in the oil separation chamber 43. Therefore, the oil separation chamber 43 separates the oil contained in the refrigerant gas discharged into the discharge chamber 41.

[0051] The refrigerant gas from which the oil has been separated flows into and passes through the inner cylinder 46. The refrigerant gas that has passed through the inner cylinder 46 then flows out to an external refrigerant circuit (not shown) through the discharge port 45. The oil separated from the refrigerant gas in the oil separation chamber 43 flows under its own weight toward the oil reservoir chamber 42 and is stored therein.

[0052] <Back Pressure Chamber> The scroll compressor 10 includes a back pressure chamber 50. The back pressure chamber 50 is formed within the housing 11. The back pressure chamber 50 is formed between the orbiting base plate 26a of the orbiting scroll 26 and the support housing 13. The back pressure chamber 50 is formed within the housing 11 on the side of the orbiting base plate 26a opposite the fixed base plate 25a. The support housing 13 separates the back pressure chamber 50 from the motor chamber 20. Refrigerant gas is introduced into the back pressure chamber 50 to urge the orbiting scroll 26 toward the fixed scroll 25. The rolling bearing 34 is a bearing disposed within the back pressure chamber 50. Therefore, the rolling bearing 34 that supports the orbiting scroll 26 so that it can rotate relative to the eccentric shaft 31 is disposed within the back pressure chamber 50.

[0053] <Air Supply Passage> The scroll compressor 10 includes an air supply passage 51. The air supply passage 51 is formed in the orbiting scroll 26. A first end of the air supply passage 51 opens at the tip of the orbiting spiral wall 26b. The first end of the air supply passage 51 is capable of communicating with the compression chamber 27. A second end of the air supply passage 51 is capable of communicating with the back pressure chamber 50. The air supply passage 51 penetrates the inner end of the orbiting spiral wall 26b, which converges in a spiral shape toward the center of the orbiting scroll 26, and the orbiting base plate 26a. As described above, the first end of the air supply passage 51 opens at the tip of the orbiting spiral wall 26b and is capable of communicating with the compression chamber 27, and the second end is capable of communicating with the back pressure chamber 50. The air supply passage 51 supplies a portion of the refrigerant gas compressed in the compression chamber 27 to the back pressure chamber 50. As a result, the pressure in the back pressure chamber 50 is higher than that in the motor chamber 20. As the pressure in the back pressure chamber 50 increases, the orbiting scroll 26 is urged toward the fixed scroll 25 so that the tip of the orbiting spiral wall 26b is pressed against the fixed base plate 25a.

[0054] <Oil Return Passage> The scroll compressor 10 is provided with an oil return passage 60. The oil return passage 60 has a first passage 61 and a second passage 62. The first passage 61 is formed in the outer peripheral wall 25c of the fixed scroll 25. The second passage 62 is formed in a portion of the orbiting base plate 26a of the orbiting scroll 26 that is located radially outward of the orbiting spiral wall 26b of the orbiting scroll 26. Therefore, the oil return passage 60 is located radially outward of the rotary shaft 15 than the supply passage 51.

[0055] As shown in FIG. 2 , the first passage 61 has a first large diameter hole 61a and a first small diameter hole 61b. The diameter of the first large diameter hole 61a is larger than the diameter of the first small diameter hole 61b. A hole 40h is formed in the gasket 40. A first end of the first large diameter hole 61a communicates with the oil reservoir 42 via the hole 40h. Therefore, the first end of the first passage 61 communicates with the oil reservoir 42. The first large diameter hole 61a communicates with a lower portion of the oil reservoir 42. The first large diameter hole 61a extends gradually upward at an angle as it moves away from the lower portion of the oil reservoir 42. The second end of the first large diameter hole 61a communicates with a first end of the first small diameter hole 61b. The first small diameter hole 61b extends in the axial direction of the rotary shaft 15 from the second end of the first large diameter hole 61a toward the bottom surface 25f of the recess 25e. The second end of the first small diameter hole 61b opens to the bottom surface 25f of the recess 25e. Therefore, the second end of the first small diameter hole 61b opens to a portion of the fixed scroll 25 that can slide against the orbiting base plate 26a. Therefore, the second end of the first passage 61 opens to a portion of the fixed scroll 25 that can slide against the orbiting base plate 26a. In this way, the first passage 61 has a first end that communicates with the oil reservoir 42 and a second end that opens to a portion of the fixed scroll 25 that can slide against the orbiting base plate 26a.

[0056] The second passage 62 has a second small diameter hole 62a and a second large diameter hole 62b. The diameter of the second small diameter hole 62a is smaller than the diameter of the second large diameter hole 62b. A first end of the second small diameter hole 62a opens to a surface of the orbiting base plate 26a that faces the orbiting spiral wall 26b and to a portion of the orbiting base plate 26a that is located radially outward of the orbiting spiral wall 26b in the direction of the rotation shaft 15. Therefore, the first end of the second passage 62 opens to a surface of the orbiting base plate 26a that faces the orbiting spiral wall 26b and to a portion of the orbiting base plate 26a that is located radially outward of the orbiting spiral wall 26b in the direction of the rotation shaft 15. Therefore, the first end of the second passage 62 opens to a portion of the orbiting base plate 26a that can slide against the fixed scroll 25. The first end of the second passage 62 can communicate with the first passage 61 through a gap between the bottom surface 25f of the recess 25e and the swivel base plate 26a. The second large diameter hole 62b extends in the axial direction of the rotary shaft 15.

[0057] The second end of the second small diameter hole 62a is connected to the first end of the second large diameter hole 62b. The second large diameter hole 62b extends in the axial direction of the rotary shaft 15. The second end of the second large diameter hole 62b opens to the end face 26e of the orbiting base plate 26a. Therefore, the second end of the second passage 62 opens to the end face 26e of the orbiting base plate 26a. In this manner, the second passage 62 penetrates the orbiting base plate 26a in the thickness direction of the orbiting base plate 26a. The second end of the second passage 62 is connected to the back pressure chamber 50. Therefore, the first end of the second passage 62 opens to a portion of the orbiting base plate 26a that can slide against the fixed scroll 25 and can communicate with the first passage 61 via the gap between the fixed scroll 25 and the orbiting scroll 26, and the second end is connected to the back pressure chamber 50. The oil return passage 60 returns the oil stored in the oil reservoir chamber 42 to the back pressure chamber 50 .

[0058] 3, the orbital locus L10 associated with the orbital motion of the orbiting scroll 26 at the first end of the second passage 62 is indicated by a two-dot chain line. As shown in FIG. 3, the second end of the first passage 61 is located at the center of the orbital locus L10 associated with the orbital motion of the orbiting scroll 26 at the first end of the second passage 62.

[0059] 2 and 3 , the scroll compressor 10 includes a seal member 65. The seal member 65 is provided on the bottom surface 25f of the recess 25e in the outer peripheral wall 25c. The seal member 65 is annular and surrounds the orbital locus L10 associated with the orbital motion of the orbiting scroll 26 at the first end of the second passage 62. The seal member 65 seals between the bottom surface 25f of the recess 25e and the orbiting base plate 26a. Therefore, the seal member 65 seals between the fixed scroll 25 and the orbiting scroll 26.

[0060] [Operation of the Embodiment] Next, the operation of the present embodiment will be described. For example, when the pressure in the back pressure chamber 50 decreases, the biasing force that biases the orbiting scroll 26 toward the fixed scroll 25 decreases, causing the tip of the orbiting spiral wall 26b to move away from the fixed base plate 25a. As a result, a portion of the refrigerant gas compressed in the compression chamber 27 is supplied to the back pressure chamber 50 through the supply passage 51, increasing the pressure in the back pressure chamber 50. Therefore, the orbiting scroll 26 is biased toward the fixed scroll 25, making it less likely that refrigerant gas will leak from the compression chamber 27. As a result, the compression efficiency of the scroll compressor 10 is improved.

[0061] Furthermore, when the pressure in the back pressure chamber 50 decreases, a portion of the swivel base plate 26a located radially outward of the rotary shaft 15 relative to the swivel volute wall 26b moves away from the bottom surface 25f of the recess 25e. As a result, in the oil return passage 60, oil flowing from the oil reservoir chamber 42 through the first passage 61 flows into the second passage 62 via the gap between the bottom surface 25f of the recess 25e and the swivel base plate 26a. The oil that has flowed into the second passage 62 is then returned to the back pressure chamber 50. In this way, when the pressure in the back pressure chamber 50 decreases, oil is returned from the oil reservoir chamber 42 to the back pressure chamber 50 via the oil return passage 60. This prevents the flow rate of oil returned from the oil reservoir chamber 42 to the back pressure chamber 50 via the oil return passage 60 from becoming too large. This avoids the problem of the oil flow rate being too high and returning to the back pressure chamber 50 via the oil return passage 60 from the oil reservoir 42 interfering with the movement of the sliding components that make up the scroll compressor 10. The oil returned to the back pressure chamber 50 from the oil reservoir 42 via the oil return passage 60 contributes to the lubrication of the rolling bearing 34 disposed within the back pressure chamber 50.

[0062] Effects of the Embodiment The above embodiment can achieve the following effects. (1) The supply passage 51 is formed in the orbiting scroll 26, and has a first end that opens to the tip of the orbiting spiral wall 26b and is capable of communicating with the compression chamber 27, and a second end that communicates with the back pressure chamber 50. The oil return passage 60 has a first passage 61 and a second passage 62. The first passage 61 is formed in the fixed scroll 25, and has a first end that communicates with the oil reservoir chamber 42 and a second end that opens to a portion of the fixed scroll 25 that can slide against the orbiting base plate 26a. The second passage 62 is formed in the orbiting scroll 26. The second passage 62 has a first end that opens to a portion of the orbiting base plate 26a that can slide against the fixed scroll 25 and is capable of communicating with the first passage 61 via the gap between the fixed scroll 25 and the orbiting scroll 26, and a second end that communicates with the back pressure chamber 50.

[0063] With this, for example, when the pressure in the back pressure chamber 50 decreases, the biasing force that biases the orbiting scroll 26 toward the fixed scroll 25 decreases, causing the tip of the orbiting spiral wall 26b to move away from the fixed scroll 25. As a result, a portion of the refrigerant gas compressed in the compression chamber 27 is supplied to the back pressure chamber 50 through the supply passage 51, increasing the pressure in the back pressure chamber 50. Therefore, the orbiting scroll 26 is biased toward the fixed scroll 25, making it less likely that refrigerant gas will leak from the compression chamber 27. As a result, the compression efficiency of the scroll compressor 10 is improved.

[0064] Furthermore, when the pressure in the back pressure chamber 50 decreases, the portion of the orbiting base plate 26a that can slide against the fixed scroll 25 moves away from the fixed scroll 25. As a result, in the oil return passage 60, oil flowing from the oil reservoir 42 through the first passage 61 flows into the second passage 62 via the gap between the fixed scroll 25 and the orbiting scroll 26. The oil that has flowed into the second passage 62 is then returned to the back pressure chamber 50. In this manner, when the pressure in the back pressure chamber 50 decreases, oil is returned from the oil reservoir 42 to the back pressure chamber 50 through the oil return passage 60. This prevents the flow rate of oil returned from the oil reservoir 42 to the back pressure chamber 50 through the oil return passage 60 from becoming too high. This avoids the problem of the oil interfering with the movement of the sliding components that make up the scroll compressor 10 due to an excessive flow rate of oil being returned from the oil reservoir 42 to the back pressure chamber 50 through the oil return passage 60. This prevents the problem of the oil interfering with the movement of the sliding components that make up the scroll compressor 10 from becoming too high. This therefore reduces power loss in the scroll compressor 10.

[0065] In this way, there is no need to provide a flow control valve in the oil return passage 60 to control the flow rate of oil returned from the oil reservoir 42 to the back pressure chamber 50 via the oil return passage 60. This makes it possible to suppress an increase in the number of parts in the scroll compressor 10. As described above, it is possible to suppress power loss in the scroll compressor 10 while suppressing an increase in the number of parts in the scroll compressor 10.

[0066] (2) The rolling bearing 34 that supports the orbiting scroll 26 so that it can rotate relative to the eccentric shaft 31 is disposed within the back pressure chamber 50. The second end of the second passage 62 is connected to the back pressure chamber 50. As a result, the oil returned from the oil reservoir chamber 42 to the back pressure chamber 50 via the oil return passage 60 contributes to lubrication of the rolling bearing 34, thereby improving the durability of the scroll compressor 10.

[0067] (3) The first end of the second passage 62 opens to a portion of the orbiting base plate 26a that can slide against the fixed scroll 25. The second passage 62 penetrates the orbiting base plate 26a in the thickness direction of the orbiting base plate 26a. This configuration is simple in terms of forming the second passage 62, the second end of which communicates with the back pressure chamber 50, in the orbiting scroll 26.

[0068] (4) The second end of the first passage 61 is located at the center of the orbital locus L10 caused by the orbital motion of the orbiting scroll 26 at the first end of the second passage 62. The scroll compressor 10 includes a seal member 65 that is annular and surrounds the orbital locus L10 caused by the orbital motion of the orbiting scroll 26 at the first end of the second passage 62, and seals the gap between the fixed scroll 25 and the orbiting scroll 26. This configuration prevents, for example, refrigerant gas from the compression chamber 27 from flowing into the oil return passage 60 through the gap between the fixed scroll 25 and the orbiting scroll 26. Furthermore, the seal member 65 prevents, for example, oil flowing through the oil return passage 60 from leaking into a suction pressure region, such as the suction passage 35 or the motor chamber 20, through the gap between the fixed scroll 25 and the orbiting scroll 26. As a result, a decrease in the flow rate of oil returned from the oil reservoir chamber 42 to the back pressure chamber 50 through the oil return passage 60 can be prevented.

[0069] (5) The oil return passage 60 is located radially outward of the rotary shaft 15 relative to the supply passage 51. This configuration in which the oil return passage 60 is located radially outward of the rotary shaft 15 relative to the supply passage 51 is suitable for configuring the oil return passage 60.

[0070] [Modifications] The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0071] In the above embodiment, the first end of the air supply passage 51 may open to a portion of the rotating base plate 26 a that can slide against the tip of the fixed spiral wall 25 b. In other words, the first end of the air supply passage 51 may open to either the tip of the rotating spiral wall 26 b or a portion of the rotating base plate 26 a that can slide against the tip of the fixed spiral wall 25 b, and may communicate with the compression chamber 27.

[0072] In the embodiment, the second end of the first passage 61 may open to a portion of the fixed base plate 25a that can slide against the tip of the orbiting spiral wall 26b. In this manner, the first passage 61 may have a first end that communicates with the oil reservoir 42 and a second end that opens to a portion of the fixed base plate 25a that can slide against the tip of the orbiting spiral wall 26b. In this case, the first end of the second passage 62 may open to the tip of the orbiting spiral wall 26b and be able to communicate with the first passage 61 through the gap between the fixed scroll 25 and the orbiting scroll 26. In this manner, the second passage 62 may have a first end that opens to the tip of the orbiting spiral wall 26b and be able to communicate with the first passage 61 through the gap between the fixed scroll 25 and the orbiting scroll 26, and a second end that communicates with the back pressure chamber 50.

[0073] In the above embodiment, the oil return passage 60 may return the oil stored in the oil reservoir chamber 42 to, for example, the motor chamber 20. The key is that the second end of the second passage 62 is in communication with at least one of the back pressure chamber 50 and the suction pressure region. Therefore, the oil return passage 60 is only required to be configured to return the oil stored in the oil reservoir chamber 42 to at least one of the back pressure chamber 50 and the suction pressure region.

[0074] In the embodiment, the oil return passage 60 may be located radially inward of the rotary shaft 15 relative to the supply passage 51. In the embodiment, a plain bearing may be used instead of the rolling bearing 34. In short, the configuration of the bearing that is disposed in the back pressure chamber 50 and supports the orbiting scroll 26 so that it can rotate relative to the eccentric shaft 31 is not particularly limited.

[0075] In the embodiment, the scroll compressor 10 does not have to be a type that is driven by the motor 22, but may be a type that is driven by, for example, a vehicle engine.

[0076] In the above embodiment, the scroll compressor 10 is used in a vehicle air conditioning system, but the use of the scroll compressor 10 is not limited thereto. In short, the scroll compressor 10 may be used in any application as long as it compresses a refrigerant, and the use of the scroll compressor 10 may be changed as appropriate.

[0077] REFERENCE SIGNS LIST 10 Scroll compressor 11 Housing 15 Rotating shaft 15e End face 20 Motor chamber which is a suction pressure region 25 Fixed scroll 25a Fixed base plate 25b Fixed spiral wall 26 Orbiting scroll 26a Orbiting base plate 26b Orbiting spiral wall 27 Compression chamber 31 Eccentric shaft 34 Rolling bearing which is a bearing 41 Discharge chamber 42 Oil storage chamber 50 Back pressure chamber 51 Air supply passage 60 Oil return passage 61 First passage 62 Second passage 65 Sealing member

Claims

a housing; a rotating shaft rotatably supported by the housing; a fixed scroll having a fixed base plate and a fixed spiral wall standing from the fixed base plate and fixed to the housing; an orbiting scroll having an orbiting base plate facing the fixed base plate and an orbiting spiral wall standing from the orbiting base plate towards the fixed base plate and meshing with the fixed spiral wall, the orbiting scroll revolving around the fixed scroll as the rotating shaft rotates; a suction pressure region into which refrigerant gas containing oil is sucked; a compression chamber defined by the fixed base plate, the fixed spiral wall, the orbiting base plate, and the orbiting spiral wall, the compression chamber compressing the refrigerant gas sucked into the suction pressure region; a discharge chamber into which the refrigerant gas compressed in the compression chamber is discharged; an oil storage chamber storing oil separated from the refrigerant gas discharged to the discharge chamber; a back pressure chamber into which refrigerant gas is introduced to urge the orbiting scroll towards the fixed scroll; and an air supply passage supplying a portion of the refrigerant gas compressed in the compression chamber to the back pressure chamber. an oil return passage for returning oil stored in the oil storage chamber to at least one of the back pressure chamber and the suction pressure region, wherein the air supply passage is formed in the orbiting scroll, and has a first end opening at one of a tip of the orbiting scroll wall and a portion of the orbiting base plate that can slide against the tip of the fixed scroll wall, thereby communicating with the compression chamber, and a second end opening to the back pressure chamber, wherein the oil return passage comprises: a first passage formed in the fixed scroll, and a first end opening to the oil storage chamber and a second end opening to a portion of the fixed scroll that can slide against the orbiting base plate; and a second passage formed in the orbiting scroll, and a first end opening to a portion of the orbiting base plate that can slide against the fixed scroll, thereby communicating with the first passage through a gap between the fixed scroll and the orbiting scroll, and a second end opening to at least one of the back pressure chamber and the suction pressure region, or a first passage formed in the fixed scroll, the first passage having a first end communicating with the oil reservoir and a second end opening to a portion of the fixed base plate that can be in sliding contact with a tip of the orbiting scroll wall;a second passage formed in the orbiting scroll, the first end of which opens at a tip of the orbiting volute wall and is capable of communicating with the first passage through a gap between the fixed scroll and the orbiting scroll, and the second end of which communicates with at least one of the back pressure chamber and the suction pressure region.

2. A scroll-type compressor as described in claim 1, characterized in that it is provided with an eccentric shaft protruding towards the revolving scroll from a position eccentric with respect to the axis of the rotating shaft on the end face of the rotating shaft, a bearing is disposed within the back pressure chamber for supporting the revolving scroll so that it can rotate relative to the eccentric shaft, and a second end of the second passage is connected to the back pressure chamber.

3. A scroll-type compressor as described in claim 2, characterized in that a first end of the second passage opens into a portion of the rotating base plate that can slide against the fixed scroll, and the second passage penetrates the rotating base plate in the thickness direction of the rotating base plate.

4. A scroll-type compressor as described in claim 3, characterized in that the second end of the first passage is located at the center of an orbital trajectory caused by the orbital motion of the orbiting scroll at the first end of the second passage, and is provided with a sealing member that is annular and surrounds the orbital trajectory and seals between the fixed scroll and the orbiting scroll.

5. A scroll compressor according to any one of claims 1 to 4, characterized in that the oil return passage is located radially outward of the rotating shaft relative to the air supply passage.

Images