screw-type compressor

Abstract

A scroll-type compressor (100) comprising: a housing (10) internally containing a fluid suction chamber (H1) and a fluid discharge chamber (H2); a scroll unit (1) provided in the housing (10) and including a fixed scroll (2) and an orbiting scroll (3) meshed with each other, in which the orbiting scroll (3) rotates about an axis of the fixed scroll (2) via a drive shaft to compress a fluid that has flowed into the suction chamber (H1) in an enclosed space (S) between the two scrolls, and to discharge the compressed fluid via the discharge chamber (H2); a bearing holder (30) provided in the housing (10) and holding a bearing (17) which rotatably supports one end of the drive shaft (21) on one side of the orbiting scroll (3), and forms a back pressure chamber (H3) in a portion between the bearing holder (30) and the orbiting scroll (3);and a back pressure control valve (50) for controlling a pressure within the back pressure chamber (H3); a fluid introduction passage (L1) communicating between the suction chamber (H1) and a space (H4) around an outer periphery of the screw unit (1); a pressure supply passage (L3) communicating between the fluid discharge chamber (H2) and the back pressure chamber (H3); and a pressure relief passage (L4) communicating between the backpressure chamber (H3) and the fluid introduction passage (L1), one end of the pressure relief passage (L4) opening to the backpressure chamber (H3) and the other end of the pressure relief passage (L4) opening to the fluid introduction passage (L1), wherein the back pressure control valve (50) is provided at an open end of the pressure relief passage (L4) on one side of the fluid introduction passage (L1), where the bearing holder (30) includes through holes (14a) extending in the extension direction of the drive shaft (21) and open at a plurality of locations on the circumferential edge (30a) of the bearing holder (30) spaced apart in the circumferential direction, and fastening screws (14) inserted into the through holes (14a) for fastening the bearing holder (30) to the stationary worm (2) and the housing (10), and wherein the fluid introduction passage (L1) extends along a recessed portion (30c) extending in the extending direction of the drive shaft (21) in a portion between the portions of the peripheral edge (30a) of the bearing holder 30 in which the through holes (14a) are formed.

Description

TECHNICAL FIELD

[0001] The present invention relates to a scroll-type compressor having a fixed scroll and an orbiting scroll meshed with each other, and compressing a fluid such as a refrigerant flowing into a space between the two scrolls. STATE OF THE ART

[0002] A scroll-type compressor of this type, which includes a scroll unit including a fixed scroll and an orbiting scroll meshed with each other, is installed, for example, in a refrigerant circuit for a vehicle air conditioner and is used to compress a refrigerant of the refrigerant circuit. The scroll unit is configured such that, by causing the orbiting scroll to rotate about an axis of the fixed scroll via a drive shaft, the volume of an enclosed space formed between the two scrolls is gradually reduced, a fluid such as a refrigerant gas that has flowed into a suction chamber is compressed within the enclosed space, and the compressed fluid is discharged via a discharge chamber.

[0003] As this scroll-type compressor, for example, a scroll-type compressor disclosed in Patent Document 1 is known. The scroll-type compressor disclosed in Patent Document 1 includes a back pressure chamber provided between an orbiting scroll and a bearing holder that rotatably supports one end of the drive shaft on the orbiting scroll side. This back pressure chamber communicates with the discharge chamber and the suction chamber. A back pressure control valve is provided in the middle of a passage that communicates between the back pressure chamber and the suction chamber, and the pressure within the back pressure chamber is controlled by the back pressure control valve, so that the pressure within the back pressure chamber becomes a pressure intermediate between the pressure within the suction chamber and the pressure within the discharge chamber.Additionally, in the scroll-type compressor disclosed in Patent Document 1, lubricating oil for lubricating a sliding portion, such as a drive shaft provided within the back pressure chamber, is supplied to the interior of the back pressure chamber. Furthermore, the lubricating oil supplied into the back pressure chamber is directly discharged into the suction chamber via the passage communicating between the back pressure chamber and the suction chamber and the back pressure control valve provided in the center of the passage communicating between the back pressure chamber and the suction chamber.

[0004] Patent Document 2 discloses a screw-type compressor that can prevent refrigerant leakage from a backpressure region and suppress mechanical losses. A groove portion is provided in an end surface of a movable scroll, and a seal member is retained in the groove portion. The seal member includes a rubber member elastically deformed in the groove portion and a plastic member made of a harder material than the rubber member.

[0005] Patent Document 3 discloses a sealing system. Patent Document 4 discloses a screw compressor.

[0006] Patent Document 5 discloses a pressure relief valve that allows flow in the reverse direction, provided in the position of the hole portion. REFERENCE DOCUMENT LISTPATENT DOCUMENT Patent Document 1: JP 2015-38327 A Patent Document 2: JP 2014-169665 A Patent document 3: JP H01 168 071 U Patent Document 4: JP S61 144 290 U Patent Document 5: JP S60 59 877 U SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, in this type of screw compressor, lubricating oil is required not only for sliding parts, such as the drive shaft within the backpressure chamber, but also for a sliding part within the scroll unit. A small amount of lubricating oil may be contained in the refrigerant gas supplied from the suction chamber to the scroll unit, but in some cases, even a small amount of lubricating oil may be insufficient to lubricate the sliding part within the scroll unit.

[0008] In this regard, the lubrication of the sliding portion within the scroll unit in the scroll-type compressor disclosed in Patent Document 1 may be insufficient because the lubricating oil is supplied only to the back pressure chamber.

[0009] The present invention has been made focusing on the above-mentioned problems, and an object of the present invention is to provide a scroll-type compressor capable of adequately lubricating not only a sliding portion within a back pressure chamber but also a sliding portion within a scroll unit. MEANS TO SOLVE THE PROBLEM

[0010] According to one aspect of the present invention, a scroll-type compressor comprises a housing internally containing a fluid suction chamber and a fluid discharge chamber; a scroll unit provided in the housing and including a fixed scroll and an orbiting scroll meshed with each other, in which the orbiting scroll rotates about an axis of the fixed scroll via a drive shaft to compress a fluid that has flowed into the suction chamber in an enclosed space between the two scrolls, and the compressed fluid is discharged via a discharge chamber; a bearing holder provided in the housing and holding a bearing that rotatably supports one end of the drive shaft on one side of the orbiting scroll and forms a back pressure chamber in a portion between the bearing support and the orbiting scroll; and a back pressure control valve for controlling a pressure within the back pressure chamber.The scroll-type compressor further includes: a fluid introduction passage formed by cooperation between an inner peripheral surface of a peripheral wall of the housing and an outer peripheral surface of the bearing holder and communicating with the suction chamber and a space around an external environment of the scroll unit; a pressure supply passage communicating between the discharge chamber and the back pressure chamber; and a pressure relief passage communicating between the back pressure chamber and the fluid introduction passage, in which the back pressure control valve is provided at an open end of the pressure relief passage on a side of the fluid introduction passage. Effects of the invention

[0011] In the scroll-type compressor according to one aspect of the present invention, a fluid in the suction chamber can be introduced into a space around the outside of the scroll unit via a fluid introduction passage, a fluid in the discharge chamber can be introduced into the back pressure chamber via the pressure supply passage, and a fluid in the back pressure chamber can be introduced to a center of the fluid introduction passage via the pressure relief passage and the back pressure control valve, and the introduced fluid is allowed to flow into the fluid introduction passage to return to the scroll unit.Thus, even if only a minute amount of lubricating oil is present in the fluid flowing from the suction chamber to the fluid introduction passage, the lubricating oil can be returned to the center of the fluid introduction passage via the pressure relief passage and the back pressure control valve, and the lubricating oil from the back pressure chamber can be supplied to the screw unit together with the lubricating oil from the suction chamber.

[0012] In the above-described manner, the scroll-type compressor capable of adequately lubricating a sliding portion of a scroll unit can be provided. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view of a scroll-type compressor according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view illustrating a mounting state of the bearing holder of the scroll-type compressor. Fig. 3 is a block diagram illustrating a flow of a refrigerant in the scroll-type compressor. Fig. Figure 4 is a cross-sectional view showing the main components of the scroll-type compressor. Fig. 5 is a view showing a modification of the bearing holder and the fixed scroll of the scroll-type compressor. Mode for carrying out the invention

[0013] An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0014] Fig. 1 is a schematic cross-sectional view of a scroll-type compressor according to the present embodiment.

[0015] The scroll-type compressor 100 according to the present embodiment is installed, for example, in a refrigerant circuit of an air conditioner for a vehicle, and compresses a refrigerant (fluid) drawn from a low-pressure side of the refrigerant circuit to discharge the compressed refrigerant. This scroll-type compressor 100 includes a scroll unit 1, a housing 10 internally defining a refrigerant suction chamber H1 and a refrigerant discharge chamber H2, an electric motor 20 serving as a drive unit driving the scroll unit 1, a bearing holder 30 for rotatably supporting one end (an upper end in Fig. 1) a drive shaft 21 of the electric motor 20, and an inverter 40 for controlling a drive of the electric motor 20. In the present embodiment, a CO 2Refrigerant is used as the above-mentioned refrigerant. In addition, an example of the scroll-type compressor 100 is a so-called inverter-integrated type compressor.

[0016] The screw unit 1 includes a fixed screw 2 and an orbiting screw 3 that mesh with each other. The fixed screw 2 includes a disc-shaped base plate 2a and a spiral turn 2b integrally formed on the base plate 2a. The orbiting screw 3 includes a disc-shaped base plate 3a and a spiral turn 3b integrally formed on the base plate 3a. Moreover, the base plate 2a of the fixed screw 2 has a diameter larger than the diameter of the base plate 3a of the orbiting screw 3.

[0017] The two scrolls 2, 3 are arranged so that both spiral wraps 2b, 3b thereof are engaged. Specifically, the two scrolls 2, 3 are arranged so that a predetermined gap is provided between one end of a protruding side of the spiral wrap 2b of the stationary scroll 2 and the base plate 3a of the orbiting scroll 3, and a predetermined gap is provided between one end of a protruding side of the spiral wrap 3b of the stationary scroll 3 and the base plate 2a of the stationary scroll 2. This gap can vary during a compression operation and is maintained within an appropriate range during the compression operation, and thus, airtightness of a below-described enclosed space (compression chamber) S can be adequately maintained.

[0018] In addition, the two scrolls 2, 3 are arranged so that the side walls of the two spiral wraps 2b, 3b are partially brought into contact with each other in a state where the angles of the two spiral wraps 2b, 3b are mutually shifted in the circumferential direction. Thus, a crescent-shaped enclosed space (compression chamber) is formed between the two spiral wraps 2b, 3b.

[0019] The stationary scroll 2 is fixed to a rear housing 12 of the casing 10 described below, and includes a recess portion 2a1 formed in the radial direction at the center of the rear housing 12 and opening toward the rear housing 12. Specifically, this recess portion 2a1 is formed on the rear surface of the base plate 2a (ie, on the end surface opposite to the orbiting scroll 3).

[0020] The orbiting scroll 3 is configured to rotate around the axis of the fixed scroll 2 via the drive shaft 21 in a state where rotation of the orbiting scroll 3 is restricted. With this configuration, the scroll unit 1 moves the enclosed space S formed by the two scrolls 2, 3, that is, between the two spiral turns 2b, 3b, toward the central portion to gradually reduce the volume of the enclosed space S. Accordingly, the scroll unit 1 compresses the refrigerant flowing into the enclosed space from the outer end of the spiral turns 2b, 3b within the enclosed space S.

[0021] With reference to Fig. 1, the casing 10 mainly includes a front casing 11 internally accommodating the scroll unit 1, the electric motor 20, the bearing holder 30, and the inverter 40, the rear casing 12, and an inverter cover 13. Further, these components (11, 12, 13) are integrally fastened by fastening means such as screws 14, and the casing 10 of the electric compressor 100 is thereby formed.

[0022] The front housing 11 includes a peripheral wall 11a having an approximately annular shape and a partition wall portion 11b. The internal space of the front housing 11 is divided by the partition wall portion 11b into an accommodating space that mainly accommodates the screw unit 1, the electric motor 20, and the bearing holder 30, and another accommodating space that accommodates the inverter 40. An opening at one end (upper end in Fig. 1) the peripheral wall 11a is closed by the rear housing 12. On the other side, an opening is provided at the other end (lower end in Fig. 1) of the peripheral wall 11a is closed by the inverter cover 13. In the partition wall portion 11b, there is a cylindrical support portion 11b1 which has a bearing 15 for supporting the other end (lower end in Fig. 1) of the drive shaft 21 is provided in the radial direction in the center of the partition wall portion 11b, and the cylindrical support portion 11b1 projects toward one end from the peripheral wall 11a.

[0023] In addition, a refrigerant suction port P1 is formed in the peripheral wall 11a. A refrigerant from a low-pressure side of the refrigerant circuit is drawn into the front housing 11 via the suction port P1. Accordingly, the space within the front housing 11 functions as the suction chamber H1. In the present embodiment, the refrigerant flows through the peripheral portion and the like of the electric motor 20 within the suction chamber H1 to thereby cool the electric motor 20. In addition, with reference to Fig. 1, a space above the electric motor 20 communicates with a space below the electric motor 20 and, together with the space below the electric motor 20, forms a suction chamber H1. Moreover, the refrigerant flows in the suction chamber H1 as a mixed fluid containing a minute amount of lubricating oil.

[0024] The rear housing 12 has a disk-like shape with an outer diameter that is aligned with an outer diameter of the peripheral wall 11a of the front housing 11. In addition, a peripheral edge of the rear housing 12 is fixed to one end of the peripheral wall 11a (upper end in Fig. 1) and an opening at one end of the front housing 11 is thus closed.

[0025] In addition, a peripheral edge of the base plate 2a of the stationary scroll 2 (to paraphrase, a portion surrounding the recess portion 2a1) is brought into contact with one end surface of the rear housing 12. A refrigerant discharge chamber H2 is partitioned by one end surface of the rear housing 12 and the recess portion 2a1 of the base plate 2a. A discharge passage L2 of a compressed refrigerant is formed in the center of the base plate 2a. In addition, a one-way valve (a check valve that regulates a flow from the discharge chamber H2 to the scroll unit 1) 16 is provided in the discharge chamber H2 to cover an opening of the discharge passage L2. The refrigerant compressed in the enclosed space S formed between the two of the spiral wraps 2b, 3b is discharged to the interior of the discharge chamber H2 via the discharge passage L2 and the one-way valve 16.Additionally, a discharge port P2 is formed in the rear housing 12, which connects the discharge chamber H2 to the outside (the high-pressure side of the refrigerant circuit). The refrigerant compressed in the discharge chamber H2 is discharged to the high-pressure side of the refrigerant circuit via the discharge port P2.

[0026] For example, although not shown in the drawings, an oil separator for separating the lubricating oil from the compressed refrigerant that has flowed into the discharge port P2 is provided. The refrigerant from which the lubricating oil has been separated by the oil separator (the refrigerant contains a refrigerant in which a minute amount of lubricating oil remains) is discharged via the discharge port P2 to the high-pressure side of the refrigerant circuit. On the other hand, the lubricating oil separated by the oil separator is introduced into a pressure supply passage L3 described below.

[0027] The electric motor 20 includes the drive shaft 21, a rotor 22, and a stator core unit 23 of the rotor 22 arranged on an outer side of the rotor 22 in the radial direction. For example, a three-phase AC motor is used. Direct currents from a battery (not shown) of a vehicle are converted into alternating currents by the inverter 40, and the converted alternating currents are supplied to the electric motor 20.

[0028] The drive shaft 21 is connected to the orbiting scroll 3 via a crank mechanism, thus transmitting the rotational force from the electric motor 20 to the orbiting scroll 3. One end of the drive shaft 21 (i.e., an end on the orbiting scroll 3 side) is inserted into a through hole formed by the bearing holder 30 and is rotatably supported by a bearing 17, and the other end of the drive shaft 21 (an end on the inverter 40 side) is rotatably supported by the bearing 15 engaged with the bearing portion 11b1. In the present embodiment, the bearing 17 is equivalent to the "bearing" according to the present invention.

[0029] The rotor 22 is supported within the stator core unit 23 via the drive shaft 21, which is engaged (e.g., by press-fitting) with a shaft hole formed in the radial direction at the center of the rotor 22. When power is supplied from the inverter 40 to the stator core unit 23 and a magnetic field is formed in the stator core unit 23, a rotational force is applied to the rotor 22, and thus the drive shaft 21 is rotationally driven.

[0030] The bearing holder 30 is provided in the front housing 11 and holds the bearing 17 that rotatably supports one end of the drive shaft 21 on the orbiting scroll 3 side. The bearing holder 30 is formed in a shape of a bottomed cylinder or the like with an outer diameter aligned with an outer diameter of the base plate 2a of the stationary scroll 2, and includes a cylindrical portion 30a and a bottom wall 30b located on the one end side of the cylindrical portion 30a. The inner diameter of the opening side of the cylindrical portion 30a is expanded to be larger than the inner diameter thereof on the bottom wall 30b side, and the cylindrical portion 30a includes a step portion 30a3 that connects between a large diameter portion 30a1 and a small diameter portion 30a2 of the cylindrical portion 30a.The orbiting scroll 3 is housed in a space partitioned by the large-diameter portion 30a1 and the step 30a3. An opening end of the cylindrical portion 30a on the orbiting scroll 3 side is brought into contact with a peripheral edge of an end face of the base plate 2a. Accordingly, the opening of the bearing holder 30 is closed by the stationary scroll 2. In addition, the bearing 17 is engaged with the small-diameter portion 30a2 of the cylindrical portion 30a. Furthermore, a through hole for inserting the end of the drive shaft 21 on the orbiting scroll 3 side in the radial direction is formed in the center of the bottom wall 30b. An appropriate sealing member 18a is provided between the bearing 17 and the bottom wall 30b, and thus, airtightness of a back pressure chamber H3 described below is maintained.

[0031] A circular thrust plate 19 is arranged between the shoulder 30a3 of the bearing holder 30 and the base plate 3a of the orbiting screw 3. The shoulder 30a3 receives a thrust force from the orbiting screw 3 via the thrust plate 19. A sealing element 18b is arranged in each portion of the shoulder 30a3 and the base plate 3a that comes into contact with the thrust plate 19.

[0032] Furthermore, the back pressure chamber H3 is separated by the sealing members 18a, 18b between the base plate 3a and the small diameter portion 30a2. That is, the back pressure chamber H3 is formed in a space between the bearing holder 30 and the orbiting scroll 3. In addition, a fluid introduction passage L1 is formed between the inner peripheral surface of the peripheral wall 11a of the front housing 11 and the outer peripheral wall of the cylindrical portion 30a of the bearing holder 30. The fluid introduction passage L1 communicates between the suction chamber H1 and a space H4 near the outer peripheries of the two spiral turns 2b, 3b of the scroll unit 1. The fluid introduction passage L1 introduces the refrigerant (specifically, a mixed fluid containing the refrigerant and a minute amount of lubricating oil) from the suction chamber H1 into the space H4.More specifically, in the present embodiment, the fluid introduction passage L1 communicating between the suction chamber H1 and the space H4 is formed by cooperation between the inner peripheral surface of the peripheral wall 11a of the front housing 11 and the outer peripheral wall of the cylindrical portion 30a of the bearing holder 30. Accordingly, the pressure within the space H4 is equal to the pressure within the suction chamber H1.

[0033] In the present embodiment, the crank mechanism includes a cylindrical projection 25 formed on the back surface of the base plate 3a (one end surface on the side of the counter-pressure chamber H3) so as to protrude from the base plate 3a, an eccentric bushing 27 mounted in an eccentric state on a crank 26 provided at one end of the drive shaft 21 on the side of the rotary screw 3, and a sliding bearing 28 engaged with the round projection 25. The eccentric bushing 27 is rotatably mounted within the round projection 25 via the sliding bearing 28. A balance weight 29 is mounted at one end of the drive shaft 21 on the side of the rotary screw 3, which counteracts the centrifugal force generated when the rotary screw 3 is operated.In addition, a rotation-locking mechanism (not shown) that restricts rotation of the orbiting scroll 3 is appropriately provided. Thus, the orbiting scroll 3 is configured to rotate around the axis of the fixed scroll 2 in a state where rotation of the orbiting scroll 3 is restricted.

[0034] Fig. 2 is a schematic cross-sectional view illustrating a fastening state of the bearing holder 30 at a cut location including the screws 14 for fastening the bearing holder 30.

[0035] With reference to Fig. 2, in the present embodiment, the bearing holder 30 is fixed integrally with the fixed screw 2 and the rear housing 12 by the fixing screws 14 in a state where the fixed screw 2 is arranged between the bearing holder 30 and the rear housing 12.

[0036] Specifically, the stationary scroll 2 is clamped between the rear housing 12 and the bearing holder 30 in a state where a peripheral edge of the rear surface of the base plate 2a is brought into contact with one end surface of the rear housing 12 and also a peripheral edge of the other end surface of the base plate 2a on the orbiting scroll 3 side is brought into contact with an opening end of the cylindrical portion 30a of the bearing holder 30.The bearing holder 30 and the stationary scroll 2 include through holes 14a, each of which is opened at the peripheral edges of the bearing holder 30 and the stationary scroll 2 (specifically, the peripheral edges of the cylindrical portion 30a and the base plate 2a) at a plurality of positions spaced apart in the circumferential direction of the bearing holder 30 to extend in the extending direction of the drive shaft 21. The fastening screws 14 for fastening the stationary scroll 2 and the rear housing 12 are inserted through the through holes 14a. In addition, nut thread portions are formed on an end surface of the rear housing 12 at positions corresponding to the opening positions of the through holes. The screws 14 are inserted into the through holes 14a of the cylindrical portion 30a and the base plate 2a to be screwed into engagement with the nut thread portions of the rear housing 12.In the manner described above, the storage holder 30 is integrally fixed to the stationary screw 2 and the rear housing 12.

[0037] In the present embodiment, the fluid introduction passage L1 extends along a recessed section 30c (see Fig. 1 and Fig. 4) extending in the extending direction of the drive shaft 21 in a portion between the portions of the peripheral edge of the bearing holder 30 (i.e., the cylindrical portion 30a) in which the through-holes 14a are formed. Specifically, the fluid introduction passage L1 is mainly formed by a portion correspondingly recessed toward the drive shaft 21 in a portion of the cylindrical portion 30a other than the portions in which the through-holes 14a are formed (i.e., the recessed portion 30c) for weight reduction, and a corresponding portion of the inner peripheral surface of the peripheral wall 11a facing the above-described portion of the cylindrical portion 30a.In addition, one end of the fluid introduction passage L1 opens to the suction chamber H1 and the other end of the fluid introduction passage L1 penetrates one end of the cylindrical portion 30a to open to the space H4.

[0038] Fig. 3 is a block diagram illustrating a flow of refrigerant in the scroll-type compressor 100.

[0039] The refrigerant from the low-pressure side of the refrigerant circuit is introduced into the suction chamber H1 via the suction port P1 and then introduced into the space H4 formed around the outer end of the scroll unit 1 via the fluid introduction passage L1. Then, the refrigerant in the space H4 is taken into an enclosed space S between the two spiral wraps 2b, 3b to be compressed in the enclosed space S. The compressed refrigerant is discharged into the discharge chamber H2 via the discharge passage L2 and the one-way valve 16, and is then discharged from the discharge chamber H2 to the high-pressure side of the refrigerant circuit via the discharge port P2. In this way, the scroll unit 1 is configured to compress the refrigerant that has flowed into the suction chamber H1 within the enclosed space S and discharge the compressed refrigerant via the discharge chamber H2.

[0040] With reference to Fig. 1, the scroll-type compressor 100 according to the present embodiment further includes a back pressure control valve 50 for controlling the pressure within the back pressure chamber H3.

[0041] In the present embodiment, the back pressure control valve 50 is a differential pressure operation type check valve that operates in a valve opening direction when the differential pressure between the pressure within the back pressure chamber H3 and the pressure within the suction chamber H1 is greater than a predetermined differential pressure, and operates in a valve closing direction when the above-mentioned differential pressure is equal to or less than the predetermined differential pressure, thereby controlling the pressure within the back pressure chamber H3 to be a predetermined pressure (intermediate pressure) between the pressure within the discharge chamber H2 (high pressure) and the pressure within the suction chamber H1 (low pressure). The arrangement position, structure, and back pressure control operation of the back pressure control valve 50 will be described in detail below.

[0042] In the present embodiment, as shown in Fig. 1 to Fig. 3, the scroll-type compressor 100 includes, in addition to the fluid introduction passage L1 and the discharge passage L2, the pressure supply passage L3 and a pressure relief passage L4.

[0043] The pressure supply passage L3 is a passage for communicating between the discharge chamber H2 and the backpressure chamber H3. The lubricating oil, separated from the compressed refrigerant in the discharge port P2 by the oil separator (not shown), is supplied to the backpressure chamber H3 via the pressure supply passage L3 and used to lubricate each sliding part within the backpressure chamber H3. The communication between the discharge chamber H2 and the backpressure chamber H3 via the pressure supply passage L3 increases the pressure within the backpressure chamber H3.

[0044] Specifically, in the present embodiment, the pressure supply passage L3 includes a passage formed in the rear housing 12, one end of which opens to the discharge chamber H2 via the discharge port P2 and the other end of which opens to the contact portion with the base plate 2a; a passage connected to the above-described passage and penetrating the base plate 2a; and a passage connected to the passage penetrating the base plate 2a and penetrating the cylindrical portion 30a to open to the back pressure chamber H3. An opening OL is provided in the center of the pressure supply passage L3. With this configuration, the lubricating oil and the like separated from the compressed refrigerant in the discharge chamber H2 are appropriately decompressed through the opening OL to be supplied to the back pressure chamber H3 via the pressure supply passage L3.

[0045] The pressure relief passage L4 is a passage for connecting between the back pressure chamber H3 and the suction chamber H1.

[0046] Specifically, in the present embodiment, the pressure relief passage L4 penetrates the small diameter portion 30a2 of the cylindrical portion 30a and extends in a direction perpendicular to the drive shaft 21. In addition, one end of the pressure relief passage L4 opens to the back pressure chamber H3 and the other end of the pressure relief passage L4 opens to the fluid introduction passage L1.

[0047] Next, the arrangement position and structure of the back pressure control valve 50 in the present embodiment will be described with reference to Fig. 3 and Fig. 4 described in detail.

[0048] Fig. 4 is an enlarged view of the main components of the present embodiment including the back pressure control valve 50, and illustrates the valve open state.

[0049] The back pressure control valve 50 includes a valve housing 51, a valve seat housing 52, a valve body 53 and an urging means 54 and is arranged at an opening end of the pressure relief passage L4 on the side of the fluid introduction passage L1, thus forming a part of the pressure relief passage L4.

[0050] The valve housing 51 includes a cylindrical portion 51a and a bottom wall 51b closing one end of the cylindrical portion 51a, and the valve housing 51 is formed as a whole in a bottomed cylindrical shape and includes a valve chamber 51c within the valve housing 51.

[0051] Outlet holes 55 opening to the fluid introduction passage L1 are formed in the cylindrical portion 51a and the bottom wall 51b, respectively. In the present embodiment, two outlet holes 55 are opened in the cylindrical portion 51a, and one outlet hole 55 is opened in the bottom wall 51b. The outlet holes 55 communicate between a space within the fluid introduction passage L1 and the valve chamber 51c within the valve housing 51.

[0052] In particular, with reference to Fig. 4, a part of the outlet hole 55 of each of two cylindrical-portion outlet holes 55a opening in the cylindrical portion 51a is located in the fluid introduction passage L1. On the other hand, also referring to Fig. 4, the entirety of the outlet hole 55 of a bottom wall outlet hole 55b opening in the bottom wall 51b is located in the fluid introduction passage L1. As described above, in the present embodiment, the back pressure control valve 50 is arranged so that at least a part of the outlet holes 55 is located in the fluid introduction passage L1. Specifically, the entirety of at least one of the plurality of outlet holes 55 (the bottom wall outlet hole 55b) is located in the fluid introduction passage L1, while the cylindrical portion outlet hole 55a is partially located in the fluid introduction passage L1.

[0053] More specifically, the backpressure control valve 50 is arranged so that the cylindrical section outlet hole 55a in the fluid introduction passage L1 opens at a position close to the pressure relief passage L4. Specifically, the cylindrical section outlet hole 55a is located above the boundary between the fluid introduction passage L1 and the pressure relief passage L4.

[0054] In addition, the cylindrical portion outlet hole 55a on the opening end side of the cylindrical portion 51a (that is, on the valve seat housing 52 side) opens toward a direction parallel with the extending direction of the fluid introduction passage L1 (to paraphrase, a direction parallel with the flow of the refrigerant flowing through the fluid introduction passage L1, which is Fig. 4 with a hollow arrow). On the other hand, the bottom wall outlet hole 55b opens in a direction perpendicular to the fluid introduction passage L1. As described above, in the present embodiment, a part of the plurality of outlet holes 55 (the cylindrical portion outlet hole 55a) opens in a direction parallel to the extending direction of the fluid introduction passage L1.

[0055] The valve seat housing 52 forms one end of the back pressure control valve 50 and is allowed to engage, for example, with an opening end of the pressure relief passage L4 on the fluid introduction passage L1 side. The valve seat housing 52 is formed, for example, in a cylindrical shape with a bottom having an outer diameter aligned with the inner diameter of the pressure relief passage L4. The valve seat housing 52 includes a cylindrical portion 52a and a bottom wall 52b located at one end of the cylindrical portion 52a, and the other end of the cylindrical portion 52a is fixed to the opening end of the valve housing 51. In the portion of the cylindrical portion 52a on the bottom wall 52b side, a valve seat portion 52c having a cone-shaped surface is formed, and the valve body 53 is brought into / out of contact with the valve seat portion 52c.The valve seat housing 52 is formed to penetrate its bottom wall 52b and includes an inlet hole 52d opening to the pressure relief passage L4 on the back pressure chamber H3 side. One end of the inlet hole 52d opens to the valve seat portion 52c, and the other end of the inlet hole 52d opens to a space of the pressure relief passage L4 on the back pressure chamber H3 side.

[0056] The valve body 53, which opens and closes the inlet hole 52d, is formed in a spherical shape, and the valve body 53 is urged in the valve seat portion 52c direction by the urging means 54.

[0057] The urging means 54 includes a coil spring 54a, one end of which is brought into contact with the bottom wall 51b of the valve housing 51, and an urging rod 54b connected to the other end of the coil spring 54a and urging the valve body 53 in the valve closing direction, and the urging means is arranged in the valve chamber 51c of the valve housing 51.

[0058] In the present embodiment, the back pressure control valve 50 includes the valve housing 51, the valve seat housing 52, the inlet hole 52d opening to the pressure relief passage L4 on the back pressure chamber H3 side, the valve body 53 opening and closing the valve hole 52d, the urging means 54, and the outlet holes 55 (55a, 55b) opening to the fluid introduction passage L1. In the back pressure control valve 50, when the differential pressure between the pressure within the back pressure chamber H3 and the pressure within the suction chamber H1 is greater than a predetermined differential pressure, the valve body 53 is moved in the valve opening direction, and when the above-mentioned differential pressure is equal to or lower than the predetermined differential pressure, the valve body 53 is moved in the valve closing direction.

[0059] Next, an overview of the operation by the back pressure control valve 50 of the scroll-type compressor 100 having the above-mentioned configuration for controlling the pressure within the back pressure chamber will be described. Note that the present embodiment is described below assuming that the back pressure control valve 50 is in the valve-closed state, the back pressure chamber H3 is connected to the discharge chamber H2 via the pressure supply passage L3 and an orifice OL, and the pressure within the back pressure chamber H3 gradually increases due to the lubricating oil and the like.

[0060] First, assume that the inlet hole 52d in the backpressure control valve 50 has closed by pressing the valve body 53 against the valve seat portion 52 by the urging means 54. In this state, the urging force of the coil spring 54a of the urging means 54 and the pressure within the suction chamber H1 transmitted via the fluid introduction passage L1 and the outlet holes 55 are applied to the valve chamber 53. Moreover, in this state, the pressure within the backpressure chamber H3 gradually increases, and when the differential pressure between the pressure within the backpressure chamber H3 and the pressure within the suction chamber H1 is greater than a predetermined differential pressure determined based on the urging force of the urging means 54, the valve body 53 is moved in the valve-opening direction against the urging force of the urging means 54.Thus, the back pressure control valve 50 reduces the pressure within the back pressure chamber H3. The lubricating oil and the like supplied to the center of the fluid introduction passage L1 via the back pressure control valve 50 flow into the flow within the fluid introduction passage L1 to return to the scroll unit 1 side (the space H4 side). When the above-mentioned differential pressure is lower than the above-mentioned predetermined differential pressure, the valve body 53 is moved in the valve closing direction by the urging force of the urging means 54. In this configuration, the back pressure control valve 50 increases the pressure within the back pressure chamber H3.

[0061] According to the scroll-type compressor 100 of the present embodiment, the refrigerant in the suction chamber H1 can be introduced into the space H4 around the outer periphery of the scroll unit 1 via the fluid introduction passage L1, the lubricating oil mainly contained in the refrigerant in the discharge chamber H2 can be introduced into the back pressure chamber H3 via the pressure supply passage L3, and the lubricating oil and the like in the back pressure chamber H3 can be guided to the center of the fluid introduction passage L1 via the pressure relief passage L4 and the back pressure control valve 50 and allowed to flow into the flow within the fluid introduction passage L1 to return to the scroll unit 1 side.In this configuration, even if the amount of lubricating oil flowing from the suction chamber H1 into the fluid introduction passage L1 is very small, the lubricating oil and the like can be returned to the center of the fluid introduction passage L1 via the pressure relief passage L4 and the back pressure control valve 50, and the lubricating oil and the like from the back pressure chamber H3 can be supplied to the scroll unit 1 together with the refrigerant from the suction chamber H1 containing the smallest amount of lubricating oil.

[0062] As described above, the scroll type compressor 100 capable of adequately lubricating the sliding portion of the scroll unit 1 can be provided.

[0063] In addition, in the present embodiment, the fluid introduction passage L1 is formed by the cooperation of the inner peripheral surface of the peripheral wall 11a of the front housing 11 and the outer peripheral surface of the bearing holder 30 (specifically, the inner surface of the recessed portion 30c). With this configuration, the fluid introduction passage L1 can be easily formed.

[0064] In addition, the back pressure control valve 50 in the present embodiment includes the inlet hole 52d opening to the pressure relief passage L4 on the back pressure chamber H3 side, the valve body 53 opening and closing the inlet hole 52d, and the outlet holes 55 opening to the fluid introduction passage L1, and in the back pressure control valve 50, the differential pressure operation type check valve is employed in which the valve body 53 is moved in the valve opening direction when the differential pressure between the pressure inside the back pressure chamber H3 and the pressure inside the suction chamber H1 is greater than the predetermined differential pressure, and the valve body 53 is moved in the valve closing direction when the above-mentioned differential pressure is equal to or lower than the above-mentioned predetermined differential pressure.With this configuration, the back pressure control valve 50 capable of automatically controlling the pressure within the back pressure chamber H3 by merely detecting the differential pressure without requiring electrical power can be provided.

[0065] In a case where the back pressure control valve 50 is a differential pressure operation type valve, if any blocking material that blocks the flow of the fluid flowing from the outlet holes 55 exists near the outlet holes 55, excessive pressure loss may be caused on the downstream side of the valve body 53. In this case, the back pressure control valve 50 cannot operate normally.

[0066] In this regard, in the present embodiment, the cylindrical portion outlet hole 55a of the outlet holes 55 opens to the fluid introduction passage L1 at a location close to the pressure relief passage L4 side. In other words, the back pressure control valve 50 is arranged so that the cylindrical portion outlet holes 55a (at least a part of the cylindrical portion outlet holes) open to the fluid introduction passage L1 at locations close to the pressure relief passage L4. With this configuration, at least a part of the outlet holes 55 (55a) can be allowed to open to a large space without any blocking material. As a result, the pressure loss on the downstream side of the valve body 53 can be suppressed, and thus the back pressure control valve 50 can be properly operated. Accordingly, even if, in the present embodiment, a CO 2-refrigerant is used as the refrigerant, the differential pressure between the pressure within the back pressure chamber H3 and the pressure within the suction chamber H1 is larger than in conventional techniques, and high controllability is required for the back pressure control valve 50, the back pressure control valve 50 capable of operating appropriately according to the predetermined differential pressure may be provided.

[0067] Additionally, in the present embodiment, at least a part of the plurality of outlet holes 55 (the cylindrical portion outlet hole 55a) opens toward the direction parallel to the extending direction of the fluid introduction passage L1. With this configuration, the lubricating oil and the like introduced to the center of the fluid introduction passage L1 via the pressure relief passage L4 and the back pressure control valve 50 can be securely allowed to flow into the flow of the fluid introduction passage L1, and thus the lubricating oil and the like can be more securely returned to the scroll unit 1 side.

[0068] Additionally, in the present embodiment, the fluid introduction passage L1 is configured to extend along the recessed portion 30c extending in the extending direction of the drive shaft 21 between the portions of the peripheral edge of the bearing holder 30 (i.e., the cylindrical portion 30a) in which the through holes 14a into which the fastening screws 14 are inserted are formed. In other words, the fluid introduction passage L1 is formed using the recessed portion 30c, which is a portion recessed for weight reduction of the front housing 11. With this configuration, the fluid introduction passage L1 can be easily formed while reducing the weight of the front housing 11.

[0069] A preferred embodiment of the present invention is as described above, but the present invention is not limited to the above-described embodiment, and various modifications and changes may be employed based on the technical idea of ​​the present invention.

[0070] For example, in the present embodiment, the orbiting screw 3 is accommodated within the bearing holder 30 (specifically, the large diameter portion 30a1), but the present invention is not limited to this, and the orbiting screw 3 may be accommodated as shown in Fig. 5, be accommodated in the stationary screw 2. In this modification in Fig.5, the present embodiment is configured such that the peripheral edge of the base plate 2a of the stationary scroll 2 protrudes toward the bearing holder 30 to form a large-diameter portion 2a3, and the orbiting scroll 3 is housed in the large-diameter portion 2a3 of the stationary scroll 2. In addition, the bearing holder 30 may include the small-diameter portion 30a2 in the cylindrical portion 30a for engagement with the bearing 17. In addition, in this modification, the fluid introduction passage L1 is formed by cooperation between the inner surface of the peripheral wall 11a of the front housing 11, the outer peripheral surface of the bearing holder 30 (the inner surface of the recessed portion 30c), and the outer peripheral surface of the stationary scroll 2 (the inner surface of the recessed portion 2c extending in conjunction with the recessed portion 30c).

[0071] In addition, the number, opening locations, and opening direction of the outlet holes 55 of the backpressure control valve 50, and the location of the fluid introduction passage L1 can be appropriately selected. For example, in the present embodiment described above, three outlet holes 55 are formed, but the number of outlet holes 55 may be one, two, or four or more. Moreover, the present embodiment is described above with reference to an exemplary configuration in which the cylindrical portion outlet hole 55a is located across the boundary between the fluid introduction passage L1 and the pressure relief passage L4, but the configuration is not limited to this, and the entire cylindrical portion outlet hole 55a may alternatively be located within the fluid introduction passage L1.When the cylindrical portion outlet hole 55a is opened in the fluid introduction passage L1 at a location near the pressure relief passage L4, the pressure loss on the downstream side of the valve body 53 can be effectively suppressed, and thus the back pressure control valve 50 can be properly operated. In addition, when the back pressure control valve 50 is provided at the opening end of the pressure relief passage L4 on the fluid introduction passage side, the lubricating oil and the like in the back pressure chamber H3 can be returned to the sliding position of the scroll unit 1 via the fluid introduction passage L1.

[0072] Moreover, the present embodiment is described above with reference to an exemplary configuration in which the scroll-type compressor 100 is a so-called inverter-integrated type compressor, however, the configuration is not limited to this, and the inverter 40 may alternatively be provided separately from the scroll-type compressor 100. In this alternative configuration, the casing 10 may include the front casing 11 and the rear casing 12.

[0073] In addition, in the present embodiment described above, a CO 2 -refrigerant is used as the refrigerant, however, the present invention is not limited to this and any suitable refrigerant may be used. EXPLANATION OF REFERENCE SYMBOLS 1 screw unit 2 stationary augers 3 circling snail 10 housings 11a Perimeter wall 14 Screw 14a Through hole 17 camps 30 Warehouse keeper section 30a cylindrical section (peripheral edge) 30c deepened section 50 Backpressure control valve 52d inlet hole 55 outlet holes 53 valve body 55a cylindrical section outlet hole (outlet hole) 55b Bottom wall outlet hole (outlet hole) 100 screw-type compressor H1 intake chamber H2 ejection chamber H3 backpressure chamber H4 Room L1 Fluid introduction passage L3 pressure supply passage L4 pressure relief passage S enclosed space

Claims

[1] A scroll-type compressor (100) comprising: a housing (10) internally containing a fluid suction chamber (H1) and a fluid discharge chamber (H2); a scroll unit (1) provided in the housing (10) and including a fixed scroll (2) and an orbiting scroll (3) meshed with each other, in which the orbiting scroll (3) rotates about an axis of the fixed scroll (2) via a drive shaft to compress a fluid that has flowed into the suction chamber (H1) in an enclosed space (S) between the two scrolls, and discharge the compressed fluid via the discharge chamber (H2); a bearing holder (30) provided in the housing (10) and holding a bearing (17) which rotatably supports one end of the drive shaft (21) on one side of the orbiting scroll (3), and forms a back pressure chamber (H3) in a portion between the bearing holder (30) and the orbiting scroll (3);and a back pressure control valve (50) for controlling a pressure within the back pressure chamber (H3); a fluid introduction passage (L1) communicating between the suction chamber (H1) and a space (H4) around an outer periphery of the screw unit (1); a pressure supply passage (L3) communicating between the fluid discharge chamber (H2) and the back pressure chamber (H3); and a pressure relief passage (L4) communicating between the backpressure chamber (H3) and the fluid introduction passage (L1), one end of the pressure relief passage (L4) opening to the backpressure chamber (H3) and the other end of the pressure relief passage (L4) opening to the fluid introduction passage (L1), wherein the back pressure control valve (50) is provided at an open end of the pressure relief passage (L4) on one side of the fluid introduction passage (L1), where the bearing holder (30) includes through holes (14a) extending in the extension direction of the drive shaft (21) and open at a plurality of locations on the circumferential edge (30a) of the bearing holder (30) spaced apart in the circumferential direction, and fastening screws (14) inserted into the through holes (14a) for fastening the bearing holder (30) to the stationary worm (2) and the housing (10), and wherein the fluid introduction passage (L1) extends along a recessed portion (30c) extending in the extending direction of the drive shaft (21) in a portion between the portions of the peripheral edge (30a) of the bearing holder 30 in which the through holes (14a) are formed. [2] The scroll-type compressor (100) according to claim 1, wherein the fluid introduction passage (L1) is formed by cooperation between an inner peripheral surface of a peripheral wall (11a) of the housing (10) and an outer peripheral surface of the bearing holder (30). [3] The scroll-type compressor (100) according to claim 1 or 2, wherein the back pressure control valve (50) includes an inlet hole (52d) opening to the pressure relief passage on the back pressure chamber (H3) side; a valve body (53) that opens and closes the inlet hole (52d); and outlet holes (55) opening to the fluid introduction passage (L1), and when a differential pressure between a pressure within the back pressure chamber (H3) and a pressure within the suction chamber (H1) is greater than a predetermined differential pressure, the valve body (53) is moved in a valve opening direction, and when the differential pressure is equal to or lower than the predetermined differential pressure, the valve body (53) is moved in a valve closing direction. [4] The scroll-type compressor (100) according to claim 3, wherein the back pressure control valve (50) is arranged so that at least a part of the discharge holes (55) opens to the fluid introduction passage (L1) at a position near the pressure relief passage (L4). [5] The scroll-type compressor (100) according to claim 4, wherein at least a part of the discharge hole (55) opens to a direction parallel to an extending direction of the fluid introduction passage (L1).

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