Compressor

Abstract

To suppress heating of an injection refrigerant flowing into a compression chamber in a compressor including an injection check valve.SOLUTION: A compressor 100 includes: a rocking scroll 40 having a rocking scroll base plate 41 and a rocking scroll spiral part 42; a stationary scroll 30 having a stationary scroll base plate 31 in which a discharge port 33 for discharging a refrigerant, an injection pipe insertion hole 31a into which an injection pipe 4 is inserted, a first injection passage 131a, and an injection check valve chamber 35 are formed, and a stationary scroll spiral part 32 which engages with the rocking scroll spiral part 42 to form a compression chamber 74; and a valve plate 21 whose one end is communicated with the first injection passage and the other end is communicated with the injection check valve chamber 35, in which a second injection passage 131b shorter than the first injection passage 131a is formed, and which is attached to the stationary scroll base plate 31.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a compressor having an injection mechanism. [Background technology]

[0002] Conventionally, refrigeration cycle devices such as refrigerators, air conditioners, and hot water heaters include a compressor that compresses a refrigerant, a condenser that dissipates heat from the compressed refrigerant, an expansion valve that reduces the pressure of the refrigerant after heat dissipation, changing the refrigerant's state from liquid to gas, and an evaporator that adds heat to adjust the refrigerant temperature to the compressor's target suction temperature, all of which are connected in sequence by piping through which the refrigerant flows. Some compressors are equipped with an injection mechanism that branches off a portion of the refrigerant flowing from the condenser to the evaporator in the refrigerant circuit and returns it to the compressor as injection refrigerant. In refrigerant circuits including compressors with an injection mechanism, the piping from the condenser to the evaporator is branched midway, and an injection pipe through which the injection refrigerant flows is provided, and the injection pipe is connected to the compressor via an expansion valve.

[0003] In a compressor with an injection mechanism, when the refrigeration cycle device is not in injection operation, the compressed refrigerant flows back from the compression chamber to the injection pipe. This causes pulsation in the injection pipe, which can lead to abnormal noise, increased pipe vibration, and pipe breakage. To suppress this pulsation in the injection pipe, some compressors are equipped with an injection check valve inside or outside the compressor. For example, Patent Document 1 discloses a configuration in which an injection check valve mechanism is provided inside a fixed scroll of the compressor and communicates with the compression chamber. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-011620 A Summary of the Invention [Problem to be solved by the invention]

[0005] Injection operation is a method of injecting an injection refrigerant, which has a lower temperature than the refrigerant discharged from the evaporator, into the compression chamber of the compressor to prevent the compressor discharge temperature from rising and exceeding the protection value when the compressor is operated at a high compression ratio, such as in cold regions. Therefore, the lower the temperature of the injection refrigerant, the smaller the injection amount needed to keep the compressor discharge temperature below the protection value.

[0006] In a compressor equipped with an injection check valve inside a fixed scroll, the injection pipe is inserted from above or beside the fixed scroll. A flow path is formed through which the injected refrigerant flows from the injection pipe insertion hole in the fixed scroll to the injection check valve mechanism. The injected refrigerant flows into the injection check valve mechanism from the top and flows out to the compression chamber connected to the bottom. Therefore, a flow path must be formed above the fixed scroll to connect the injection pipe insertion hole formed in the fixed scroll to the top of the injection check valve mechanism. Furthermore, a discharge space is formed above the base plate of the fixed scroll, from which compressed, high-temperature, high-pressure refrigerant is discharged. Therefore, when the injected refrigerant passes through the flow path formed above the fixed scroll, the heat of the high-temperature, high-pressure refrigerant discharged into the discharge space is transferred to the fixed scroll, heating the injected refrigerant. Heating the injected refrigerant increases the amount of injected refrigerant required to maintain the compressor discharge temperature within a protective value. This increases the amount of refrigerant injected into the compression chamber, which increases the torque required for compression and increases the loss that occurs.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to suppress heating of the injection refrigerant flowing into the compression chamber in a compressor equipped with an injection check valve. [Means for solving the problem]

[0008] The compressor according to the present disclosure comprises: an orbiting scroll base plate; an orbiting scroll having an orbiting scroll spiral portion formed protruding from the orbiting scroll base plate; a fixed scroll base plate formed with a discharge port for discharging a refrigerant and an injection pipe insertion hole into which an injection pipe through which an injection refrigerant flows is inserted; a fixed scroll having a fixed scroll spiral portion formed protruding from the fixed scroll base plate and meshing with the orbiting scroll spiral portion to form a compression chamber that communicates with the discharge port; and a valve plate attached to a surface of the fixed scroll base plate opposite to the surface on which the fixed scroll spiral portion is formed; the fixed scroll base plate is formed with a first injection flow path that communicates with the injection pipe insertion hole and an injection check valve chamber that communicates with the compression chamber and houses an injection check valve mechanism; and the valve plate is formed with a second injection flow path having one end that communicates with the first injection flow path and the other end that communicates with the injection check valve chamber and is shorter than the first injection flow path.

[0009] The compressor according to the present disclosure also comprises: an orbiting scroll base plate; an orbiting scroll having an orbiting scroll spiral portion formed to protrude from the orbiting scroll base plate; a fixed scroll base plate formed with a discharge port for discharging refrigerant and an injection pipe insertion hole into which an injection pipe through which injection refrigerant flows is inserted; and a fixed scroll having a fixed scroll spiral portion formed to protrude from the fixed scroll base plate and which forms a compression chamber communicating with the discharge port by meshing with the orbiting scroll spiral portion, wherein the fixed scroll base plate is characterized in that it is formed with a first injection flow path communicating with the injection pipe insertion hole, an injection check valve chamber communicating with the compression chamber and accommodating an injection check valve mechanism, and a second injection flow path having one end communicating with the first injection flow path and the other end communicating with the injection check valve chamber, the second injection flow path being shorter than the first injection flow path and located farther from the compression chamber than the first injection flow path. [Effects of the Invention]

[0010] According to the present disclosure, a compressor including an injection check valve can be obtained that suppresses heating of the injection refrigerant flowing into the compression chamber. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a vertical cross-sectional view showing a compressor according to a first embodiment. [Figure 2] 1 is an enlarged vertical cross-sectional view showing the configuration of a compression mechanism in a compressor according to a first embodiment. [Figure 3] 1 is a schematic diagram showing a refrigerant circuit including a compressor according to a first embodiment. [Figure 4] 3 is a cross-sectional view showing the injection mechanism of the compressor according to the first embodiment, with the injection check valve in an open state. FIG. [Figure 5] 3 is a cross-sectional view showing the injection mechanism of the compressor according to the first embodiment, with the injection check valve in a closed state. FIG. [Figure 6] 1 is a top view of a fixed scroll of a compressor according to a first embodiment. [Figure 7] FIG. 2 is a top view of a valve plate of the compressor according to the first embodiment. [Figure 8] 2 is a top view of a fixed scroll to which a valve plate of the compressor according to the first embodiment is attached. FIG. [Figure 9] 4 is a top view of a modified example of a fixed scroll to which a valve plate of the compressor according to the first embodiment is attached. [Figure 10] FIG. 10 is a cross-sectional view showing the injection mechanism of the compressor according to the second embodiment, with the injection check valve in an open state. [Figure 11] FIG. 10 is a cross-sectional view showing the injection mechanism of the compressor according to the second embodiment, with the injection check valve in a closed state. [Figure 12] FIG. 11 is a cross-sectional view showing an injection mechanism of a compressor according to a third embodiment, with an injection check valve in an open state. [Figure 13] FIG. 10 is a cross-sectional view showing an injection mechanism of a compressor according to a third embodiment, with an injection check valve in a closed state. [Figure 14] FIG. 10 is a cross-sectional view showing an injection mechanism of a compressor according to a fourth embodiment, with a reed valve in an open state. [Figure 15] FIG. 10 is a cross-sectional view showing an injection mechanism of a compressor according to a fourth embodiment, with a reed valve in a closed state. [Figure 16] FIG. 10 is a cross-sectional view showing a modified example of the injection mechanism of the compressor according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Embodiments of the present disclosure will be described with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant descriptions are appropriately simplified or omitted. The present disclosure is not limited to the following embodiments, and any of the components of the embodiments may be modified, combined, or omitted without departing from the spirit of the present disclosure. Furthermore, to facilitate understanding, directional terms (e.g., "upper," "lower," etc.) are used as appropriate, but these notations are merely used for the convenience of explanation and do not limit the arrangement or orientation of devices or components.

[0013] Embodiment 1 FIG. 1 is a longitudinal cross-sectional view showing a compressor 100 according to a first embodiment of the present disclosure. FIG. 2 is a longitudinal cross-sectional view showing a configuration of a compression mechanism 110 in the compressor according to the first embodiment of the present disclosure. The compressor 100 is a low-pressure shell compressor in which a shell 1 is filled with a low-pressure refrigerant. The compressor 100 is applied to refrigeration cycle devices used for refrigeration or air conditioning purposes, such as refrigerators, freezers, vending machines, air conditioners, refrigeration systems, and water heaters. The compressor 100 draws in refrigerant circulating through a refrigerant circuit 200 of the refrigeration cycle device, compresses it, and discharges it into a high-temperature, high-pressure state. First, the overall configuration of the compressor 100 will be described using FIGS. 1 and 2.

[0014] The compressor 100 is configured by housing a compression mechanism 110, which is configured with a fixed scroll 30 and an orbiting scroll 40, a drive mechanism 120, a shaft 7, a frame 6, a sub-frame 8, and an Oldham ring 11, inside a shell 1 that forms the outer casing of the compressor 100. The inside of the shell 1 is divided by the frame 6 into a suction space 71 into which low-pressure refrigerant is drawn from the outside and a discharge space 72 filled with high-pressure refrigerant discharged to the outside, and the suction space 71 is divided by the sub-frame 8 into an oil reservoir 5 that stores refrigeration oil to lubricate the various components.

[0015] The shell 1 includes a middle shell 1b, an upper shell 1a disposed above the middle shell 1b, and a lower shell 1c disposed below the middle shell 1b, and constitutes the outer casing of the compressor 100. A suction pipe 2 for drawing in a refrigerant is provided on the side of the middle shell 1b. The suction pipe 2 is connected to a suction space 71. A discharge pipe 3 for discharging the refrigerant and an injection pipe 4 for drawing in an injection refrigerant are connected to the upper shell 1a. The injection pipe 4 is one of the components of an injection mechanism 130, which will be described later. The injection mechanism 130 serves to inject medium-pressure refrigerant discharged from a condenser 201 in a refrigerant circuit 200, which will be described later, into a compression chamber 74 of the compression mechanism 110. Details of the injection mechanism 130 will be described later. The discharge pipe 3 is connected to the discharge space 72. The injection pipe 4 is connected to an expansion valve 204 of the refrigerant circuit 200 and an injection pipe insertion hole 31a formed on the back surface of a fixed scroll 30 of the compression mechanism 110. The expansion valve 204 is, for example, an LEV (linear electronic expansion valve). Within the compressor 100, below the frame 6, there is formed a suction space 71 filled with refrigerant flowing in from the suction pipe 2. Within the shell 1, there is formed a discharge space 72 filled with refrigerant discharged from the compression mechanism 110, on the discharge pipe 3 side of the compression mechanism 110.

[0016] Inside the shell 1, the compression mechanism 110 is disposed in the upper part of the shell 1, and the drive mechanism 120 is disposed in the lower part of the shell 1. The compression mechanism 110 and the drive mechanism 120 are connected via a shaft 7. A rotational force generated in the drive mechanism 120 is transmitted to the compression mechanism 110 via the shaft 7. In the compression mechanism 110, the refrigerant is compressed by the rotation of the shaft 7. In the following description, the direction of the rotation axis around which the shaft 7 is rotated by the drive mechanism 120 is referred to as the axial direction.

[0017] The drive mechanism 120 is installed inside the shell 1, between the frame 6 and the subframe 8, and generates rotational motion to rotate the shaft 7. The drive mechanism 120 includes a stator 15 fixed to the inner circumferential wall of the middle shell 1b and a rotor 16 rotatably disposed on the inner circumferential side of the stator 15. The stator 15 rotates the rotor 16 using power supplied from outside the compressor 100. The stator 15 is configured, for example, by mounting multi-phase windings on a laminated core. A shaft 7, which transmits the rotational driving force of the drive mechanism 120 to the orbiting scroll 40, is fixed to the rotor 16. When power is supplied to the stator 15, the rotor 16 rotates on its own axis, thereby rotating integrally with the shaft 7. The drive mechanism 120 can change the rotation speed of the shaft 7, for example, by inverter control. The compressor 100 is, for example, a compressor with a maximum operating speed of 100 rps or more.

[0018] The compression mechanism 110 is housed in the shell 1 and compresses the refrigerant drawn into the shell 1 from the suction pipe 2. The compression mechanism 110 includes a fixed scroll 30 fixed to the shell 1 and an orbiting scroll 40 that orbits relative to the fixed scroll 30. In the compression mechanism 110, a fixed scroll spiral portion 32 of the fixed scroll 30 (described later) and an orbiting scroll spiral portion 42 of the orbiting scroll 40 (described later) mesh with each other to form a compression chamber 74 in which the refrigerant is compressed. As shown in FIG. 1 , the fixed scroll 30 is disposed above the orbiting scroll 40.

[0019] The fixed scroll 30 has a fixed scroll base plate 31 and a fixed scroll spiral portion 32 extending downward from the lower surface of the fixed scroll base plate 31. The fixed scroll 30 is fixed to the inner wall of the shell 1 via the frame 6. The fixed scroll 30 is fixed to the shell 1, for example, by fastening it to the upper end of the frame 6 with fasteners such as bolts so that the fixed scroll 30 closes a cylindrical opening of the frame 6 (described later). In this case, the fixed scroll 30 is indirectly fixed to the shell 1 via the frame 6. Note that the fixed scroll 30 may also be fixed directly to the middle shell 1b of the shell 1 without being fixed to the frame 6.

[0020] The fixed scroll spiral portion 32 protrudes downward from the surface of the fixed scroll base plate 31 that faces the orbiting scroll 40, i.e., the lower surface, toward the orbiting scroll 40. The cross section of the fixed scroll spiral portion 32 parallel to the fixed scroll base plate 31 is formed in a spiral shape.

[0021] A valve plate 21 is attached with fasteners such as bolts to a fixed scroll base plate upper surface 31c, which is the surface of the fixed scroll base plate 31 opposite to the surface on which the fixed scroll spiral portion 32 is formed. A seal material, such as a gasket 19, to prevent leakage of high and low pressure refrigerant may be arranged on the surface of the fixed scroll base plate 31 to which the valve plate 21 is attached and on the contact surface between the valve plate 21 and the surface of the fixed scroll base plate 31. A discharge port 33 is formed in the center of the fixed scroll base plate 31, penetrating the fixed scroll base plate 31 and the valve plate 21, for discharging refrigerant compressed in the compression chamber 74 to the discharge space 72.

[0022] The valve plate 21 is fitted with a discharge valve 22 and a discharge valve holder 22a that close the discharge port 33, and an over-compression relief valve 23 and an over-compression relief valve holder 23a that close the over-compression relief port 34. The discharge valve 22 and the over-compression relief valve 23 are reed valves and are arranged on the surface of the valve plate 21 facing the discharge space 72. The discharge valve 22 opens and closes the discharge port 33 in response to the discharge pressure of the refrigerant. The over-compression relief valve 23 opens and closes the over-compression relief port 34 in response to the discharge pressure of the refrigerant. The valve holder 22a and the over-compression relief valve holder 23a support the reed valves from their backsides when the discharge valve 22 and the over-compression relief valve 23 are open, protecting them from excessive deformation. Note that, although this embodiment will be described assuming that the discharge valve 22 and the over-compression relief valve 23 are reed valves, any mechanism that opens and closes the discharge port 33 and the over-compression relief port 34 in response to the discharge pressure may be used.

[0023] The valve plate 21 also has the effect of suppressing deformation of the fixed scroll 30. The fixed scroll 30 may deform due to an increase in internal pressure in the compression chamber 74. As the fixed scroll 30 deforms, the fixed scroll spiral portion 32 also deforms, and the fixed scroll spiral portion 32 and the orbiting scroll spiral portion 42 no longer mesh properly. Therefore, by attaching the valve plate 21 to the upper surface 31c of the fixed scroll base plate, the pressure resistance of the fixed scroll 30 is improved.

[0024] The orbiting scroll 40 has an orbiting scroll base plate 41 and an orbiting scroll spiral portion 42 extending upward from the upper surface of the orbiting scroll base plate 41. The orbiting scroll 40 is attached to the shaft 7 eccentrically with respect to the rotation axis of the shaft 7, which will be described later. Therefore, the orbiting scroll 40 performs an eccentric orbital motion with respect to the fixed scroll 30.

[0025] The orbiting scroll spiral portion 42 protrudes from the surface of the orbiting scroll base plate 41 facing the fixed scroll 30, i.e., the upper surface, toward the fixed scroll 30, i.e., upward. A cross section of the orbiting scroll spiral portion 42 parallel to the orbiting scroll base plate 41 is formed in a spiral shape. The fixed scroll spiral portion 32 and the orbiting scroll spiral portion 42 mesh with each other to form a compression chamber 74. When the orbiting scroll 40 is oscillated by the shaft 7, the gaseous refrigerant is compressed in the compression chamber 74. Seal members 14 are disposed at the tips of the fixed scroll spiral portion 32 and the orbiting scroll spiral portion 42 to maintain the airtightness of the compression chamber 74.

[0026] A hollow cylindrical orbiting scroll boss 43 is formed in the center of the bottom surface of the orbiting scroll base plate 41, i.e., the surface opposite to the surface on which the orbiting scroll spiral portion 42 is formed. The eccentric shaft portion 7a at the upper end of the shaft 7 is inserted into the orbiting scroll boss 43. A cylindrical slider 12 (described later) is attached to the eccentric shaft portion 7a. By inserting the eccentric shaft portion 7a of the shaft 7 into the orbiting scroll boss 43, the orbiting scroll boss 43 and the shaft 7 are engaged via the slider 12. A rocking bearing portion 43a made of a copper alloy, such as a bronze-based metal, is provided on the inner circumferential surface of the orbiting scroll boss 43, on which the slider 12 slides. The rocking bearing portion 43a is fixed to the orbiting scroll boss 43 by press-fitting a bearing material used for sliding bearings, such as a copper alloy. To prevent rotation, the rocking bearing portion 43a may be fixed to the orbiting scroll boss 43 with a fixing device, such as a pin. The oscillating scroll boss 43 and the slider 12 may be configured to contact each other without providing the oscillating bearing portion 43a. The slider 12 slides on the oscillating bearing portion 43a via an oil film, or on the inner peripheral surface of the oscillating scroll boss 43 if the oscillating bearing portion 43a is not provided. The slider 12 is made of, for example, sintered metal. The oscillating bearing portion 43a may be made of a composite metal containing a resin material such as polytetrafluoroethylene resin. By making the slider 12 out of sintered metal with excellent heat resistance and making the oscillating bearing portion 43a that comes into contact with the slider 12 out of a composite metal containing a resin material, it is possible to improve heat resistance and reduce wear. The detailed configuration of the slider 12 will be described later.

[0027] The orbiting scroll base plate 41 has a thrust surface 44 that supports a thrust load on the surface opposite to the surface on which the orbiting scroll spiral portion 42 is formed. The thrust surface 44 is supported by a frame 6 fixed within the shell 1. That is, the orbiting scroll 40 is supported by the frame 6 against an axial thrust load. The orbiting scroll 40 oscillates on a thrust bearing 6a of the frame 6 (described later) as the shaft 7 rotates. The thrust surface 44 is provided with radial oil supply grooves (not shown) for supplying lubricating oil. The orbiting scroll 40 is restricted in its rotational motion by an Oldham ring 11 (described later) and revolves around the fixed scroll 30. A pair of orbiting scroll base plate Oldham grooves 45, arranged 180 degrees apart, are formed on the outer periphery of the lower surface of the orbiting scroll base plate 41 of the orbiting scroll 40. A pair of Oldham ring upper claws 11a of the Oldham ring 11 (described later) engage with the pair of orbiting scroll base plate Oldham grooves 45.

[0028] The Oldham ring 11 is disposed between the orbiting scroll 40 and the frame 6. The Oldham ring 11 has an annular Oldham ring circular portion 11c, on which a pair of Oldham ring upper claws 11a protruding upward and spaced 180 degrees apart, and a pair of Oldham ring lower claws 11b protruding downward and spaced 180 degrees apart. The Oldham ring upper claws 11a and the Oldham ring lower claws 11b are positioned such that they have a phase difference of approximately 90 degrees. The Oldham ring circular portion 11c is accommodated in an Oldham accommodating portion 6b formed in a thrust bearing 6a of the frame 6. A pair of frame Oldham grooves 6c are formed in the bottom of the Oldham accommodating portion 6b at positions perpendicular to the pair of orbiting scroll base plate Oldham grooves 45 when the orbiting scroll 40 is disposed on the frame 6. The Oldham ring upper claw 11a is engaged with the orbiting scroll base plate Oldham groove 45 of the orbiting scroll 40, and the Oldham ring lower claw 11b is engaged with the frame Oldham groove 6c of the frame 6. The Oldham ring 11 prevents the orbiting scroll 40 from rotating on its axis and allows the orbiting scroll 40 to orbit.

[0029] The frame 6 is formed in a cylindrical shape, its outer periphery is fixed to the shell 1, and its inner periphery houses the compression mechanism 110. The frame 6 supports the orbiting scroll 40 of the compression mechanism 110 so that it can freely oscillate. The frame 6 has a thrust bearing 6a facing the lower surface of the orbiting scroll base plate 41, and the thrust load generated during operation of the compressor 100 is supported by the thrust bearing 6a via the thrust surface 44 of the orbiting scroll 40.

[0030] Furthermore, a frame boss 6d that supports the shaft 7 is formed on the side of the frame 6 facing the drive mechanism 120, i.e., on the lower side of the frame 6. A shaft hole is formed in the frame boss 6d, and the main shaft portion 7b of the shaft 7 is inserted into this shaft hole. A cylindrical sleeve 13 (described below) is attached to the main shaft portion 7b. In the example shown in FIG. 1, a main bearing portion 6e made of a copper alloy, such as a bronze-based metal, is provided on the inner circumferential surface of the frame boss 6d. The main bearing portion 6e is fixed to the inner surface of the frame boss 6d by press-fitting a bearing material used in sliding bearings, such as a copper alloy. Note that the main bearing portion 6e may be omitted, and the sleeve 13 attached to the main shaft portion 7b may be in contact with the frame boss 6d. The frame boss 6d rotatably supports the main shaft portion 7b of the shaft 7 via the main bearing portion 6e and the sleeve 13. The sleeve 13 slides against the main bearing portion 6e via an oil film. Note that the detailed configuration of the sleeve 13 will be described later.

[0031] Furthermore, a boss accommodating portion 6f, which is a substantially cylindrical space for accommodating the orbiting scroll boss 43, is formed between the thrust bearing 6a and the frame boss 6d in the center of the frame 6. The boss accommodating portion 6f is a space in which the orbiting scroll boss 43 operates when the shaft 7 is rotating, i.e., when the compressor 100 is operating. During operation of the compressor 100, the orbiting scroll boss 43 of the orbiting scroll 40 oscillates within the boss accommodating portion 6f of the frame 6.

[0032] The shaft 7 connects the drive mechanism 120 and the orbiting scroll 40, and transmits the rotational motion of the drive mechanism 120 to the orbiting scroll 40 of the compression mechanism 110. A main shaft portion 7b of the shaft 7, which is located above the rotor 16 of the drive mechanism 120, is rotatably supported by a main bearing portion 6e provided on the frame 6. A sub-shaft portion 7c of the shaft 7, which is located below the rotor 16 of the drive mechanism 120, is rotatably supported by a sub-bearing 8b of a sub-frame 8, which will be described later. An oil pump 10 is disposed at the lower end of the shaft 7, which sucks up oil accumulated in the oil reservoir 5. A shaft oil supply hole 7d is formed inside the shaft 7, which allows the oil sucked up by the oil pump 10 to circulate upward.

[0033] A slider 12 is attached to the outer peripheral surface of the eccentric shaft portion 7a that constitutes the upper end of the shaft 7. The slider 12 is disposed within the orbiting scroll boss 43. The orbiting scroll 40 is attached to the shaft 7 via the slider 12. This allows the orbiting scroll 40 to rotate as the shaft 7 rotates. The eccentric shaft portion 7a and main shaft portion 7b of the shaft 7 may be provided with a crowning mechanism that suppresses tilting of the slider 12 and sleeve 13.

[0034] The slider 12 is a cylindrical member having a hollow portion formed therein into which the eccentric shaft portion 7a of the shaft 7 is inserted. The slider 12 is rotatably housed in the oscillating scroll boss 43. The slider 12 is disposed between the inner peripheral surface of the oscillating scroll boss 43 and the eccentric shaft portion 7a, and allows the oscillating radius of the oscillating scroll 40 to be variable. The slider 12 rotates integrally with the shaft 7 and is disposed so as to slide relative to the oscillating bearing portion 43a. The hollow portion of the slider 12 and the eccentric shaft portion 7a of the shaft 7 are formed so that the eccentric shaft portion 7a fits into the hollow portion of the slider 12 and the slider 12 slides only in a fixed direction on a plane perpendicular to the axial direction of the shaft 7. Note that the slider 12 and the shaft 7 are not limited to the above description as long as they are configured to rotate integrally. The slider 12 and the shaft 7 may be configured to rotate integrally by, for example, engagement of a detent pin with a detent groove, engagement of a key with a key groove, press fitting, or shrink fitting.

[0035] The sleeve 13 is a cylindrical member having a hollow portion formed therein into which the main shaft portion 7b of the shaft 7 is inserted. The main shaft portion 7b of the shaft 7, which is located above the drive mechanism 120, is inserted into the hollow portion of the sleeve 13. The sleeve 13 is disposed between the main bearing portion 6e and the main shaft portion 7b of the shaft 7. The sleeve 13 is configured to rotate integrally with the shaft 7 and slide relative to the main bearing portion 6e. A detent portion (not shown) is formed on the inner circumferential wall that forms the hollow portion of the sleeve 13. The detent portion is formed by recessing the inner circumferential wall at the vertical end of the sleeve 13 to form a groove. The detent portion formed on the inner circumferential wall of the sleeve 13 engages with a detent pin (not shown) formed on the outer circumferential wall of the main shaft portion 7b of the shaft 7, allowing the sleeve 13 to rotate integrally with the shaft 7. Note that the sleeve 13 and the shaft 7 are not limited to the above description as long as they are configured to rotate integrally. The sleeve 13 and the shaft 7 may be configured to rotate integrally by, for example, engagement between a key and a key groove, press fitting, shrink fitting, or the like.

[0036] The oil pump 10 is fixed to the lower end of the shaft 7. The oil pump 10 is a positive displacement pump such as a trochoid pump. As the shaft 7 rotates, the oil pump 10 pumps oil stored in the oil reservoir 5 through a shaft oil supply hole 7d provided inside the shaft 7. The oil pumped by the oil pump 10 through the shaft oil supply hole 7d is supplied to the bearings and the compression chambers 74 for the purpose of lubricating the bearings and sealing the gaps in the compression chambers 74. The oil used in the compressor 100 is, for example, polyol ester oil. In recent years, the capacity of refrigeration cycle devices has increased, and the amount of refrigerant sealed in the refrigerant circuit 200 has also increased. Furthermore, as the capacity increases, the piping length becomes longer, which impairs the return of oil to the compressor 100. Therefore, it is desirable to use polyol ester oil, which is compatible with the refrigerant, as the oil used in the compressor 100. When using polyol ester oil in a low-pressure shell, the oil viscosity grade (VG) should be 32 or higher and less than 68 to prevent an increase in oil viscosity and deterioration of sliding loss.

[0037] The sub-frame 8 is disposed below the drive mechanism 120 inside the shell 1 and is fixed to the inner peripheral surface of the middle shell 1b. The sub-frame 8 rotatably supports the sub-shaft portion 7c of the shaft 7 via a sub-bearing 8b. The shaft 7 slides on the sub-bearing 8b via an oil film. In FIG. 1, the sub-bearing 8b is illustrated as a ball bearing, but the sub-bearing 8b is not limited to a ball bearing and may be configured as another type of bearing. The sub-bearing 8b is fitted into a sub-bearing housing portion 8a fixed to the center of the sub-frame 8.

[0038] Next, the operation of the compressor 100 will be described. When power is supplied to the stator 15 from outside the compressor 100, a magnetic field is generated in the stator 15. This magnetic field acts to rotate the rotor 16. That is, when power is supplied to the stator 15, torque is generated in the rotor 16. As the rotor 16 rotates, the shaft 7 fixed to the rotor 16 also rotates. The orbiting scroll 40 connected to the shaft 7 is restricted from rotating on its own axis by the Oldham ring 11 that reciprocates inside the frame Oldham groove 6c of the frame 6, and thus revolves. As the orbiting scroll spiral portion 42 revolves, the volume of the compression chamber 74 formed by the meshing of the fixed scroll spiral portion 32 and the orbiting scroll spiral portion 42 changes.

[0039] The gaseous refrigerant drawn into the shell 1 from the suction pipe 2 is taken into a compression chamber 74 formed between the fixed scroll spiral portion 32 and the orbiting scroll spiral portion 42. As the orbiting scroll 40 revolves, the refrigerant is compressed while moving from the outer periphery of the compression chamber 74 toward the center. The compressed refrigerant is discharged from a discharge port 33 formed in the fixed scroll base plate 31 by opening a discharge valve 22, and is then discharged from the discharge pipe 3 to the outside of the compressor 100.

[0040] In the compressor 100, the lubricating oil stored in the oil reservoir 5 below the shell 1 is supplied from a shaft oil supply hole 7d provided in the shaft 7 to each sliding part, such as the frame boss 6d, the auxiliary bearing 8b, and the thrust surface 44 of the orbiting scroll 40. The lubricating oil supplied to the thrust surface 44 is first sucked up by the oil pump 10 and lubricates the bearing structure of the eccentric shaft portion 7a. After lubricating the bearing structure of the eccentric shaft portion 7a, the lubricating oil is stored in the boss housing portion 6f of the frame 6 and then flows through radial oil supply grooves provided in the thrust surface 44 to the Oldham groove 45 of the orbiting scroll base plate, where it lubricates the Oldham ring 11.

[0041] Fig. 3 is a schematic diagram showing a refrigerant circuit 200 including a compressor 100 according to the first embodiment. The operation of the compressor 100 in the refrigerant circuit 200 will be described with reference to Fig. 3. The refrigerant circuit 200 includes the compressor 100, a condenser 201, an expansion device 202, and an evaporator 203, which are connected by refrigerant piping 205. In the refrigerant circuit 200, the refrigerant piping 205 between the condenser 201 and the expansion device 202 branches, and an injection refrigerant piping 205a and an expansion valve 204 are connected to the refrigerant. The arrows in Fig. 3 indicate the direction in which the refrigerant flows.

[0042] The compressor 100 compresses the low-pressure gas refrigerant taken in, changing it into high-temperature, high-pressure gas refrigerant. The condenser 201 dissipates heat from the high-temperature, high-pressure gas refrigerant sent from the compressor 100 into the surrounding air, changing the gas refrigerant into high-pressure liquid refrigerant. The expansion device 202 reduces the pressure of the high-pressure liquid refrigerant sent from the condenser 201, changing it into low-temperature, low-pressure liquid refrigerant. The expansion device 202 is composed of, for example, an expansion valve. The evaporator 203 vaporizes the liquid refrigerant sent from the expansion device 202, changing it into low-pressure gas refrigerant. When the refrigerant changes from a liquid state to a gas state in the evaporator 203, it absorbs heat from the surrounding air, cooling the air. The gas refrigerant discharged from the evaporator 203 is taken back into the compressor 100. The refrigerant circuit 200 utilizes heat radiation in a condenser 201 of the refrigerant or heat absorption in an evaporator 203, and is used in refrigeration cycle devices such as air conditioners, refrigerators, and water heaters.

[0043] The configuration of the refrigerant circuit 200 to which the compressor 100 is applied is not limited to the configuration shown in Fig. 3. For example, the refrigerant circuit 200 may be configured to switch between heating operation and cooling operation. In this case, the refrigerant circuit 200 includes a flow path switching device that switches the flow path through which the refrigerant flows between the cooling operation and the heating operation. The flow path switching device is configured, for example, with a four-way valve.

[0044] The refrigerant circuit 200 also includes an expansion valve 204, which branches off from a refrigerant pipe 205 flowing from the condenser 201 and being sent to the expansion device 202. The expansion valve 204 injects a portion of the refrigerant discharged from the condenser 201 as injection refrigerant into the compressor 100. By injecting the injection refrigerant discharged from the condenser 201 into the compression chamber 74 of the compressor 100, an excessive rise in temperature of the gas refrigerant discharged from the compressor 100 can be prevented. A refrigeration cycle apparatus using the refrigerant circuit 200 includes a control unit (not shown) that controls the opening and closing of the expansion valve 204. When the discharge temperature of the gas refrigerant discharged from the compressor 100 exceeds a set value, the control unit opens the expansion valve 204 to inject the injection refrigerant into the compressor 100, thereby lowering the discharge temperature of the compressor 100. The set value is set based on, for example, a protection value, which is an upper limit of the discharge temperature set to prevent deterioration of refrigeration oil or burnout of the compressor 100. Hereinafter, the injection of injection refrigerant into the compressor 100 to operate the refrigeration cycle apparatus will be referred to as injection operation. The injection operation is not limited to when the discharge temperature of the gas refrigerant discharged from the compressor 100 exceeds a set value. For example, the control unit may determine whether to perform the injection operation based on the outside air temperature. In particular, in an environment with low outside air temperatures, the pressure on the low-pressure side of the refrigerant circuit 200 decreases, resulting in operation at a high compression ratio and a high discharge temperature of the compressor 100. This necessitates the injection operation. Furthermore, when a refrigerant containing R32 is used, the discharge temperature is more likely to rise due to pressure increase by the compressor 100 compared to other refrigerants such as R410A. Therefore, the injection operation reduces the discharge temperature of the compressor 100, enabling stable operation of the compressor 100.

[0045] The compressor 100 includes an injection mechanism 130 that injects injection refrigerant into the compression chamber 74. FIG. 4 is a cross-sectional view showing the injection mechanism 130 of the compressor 100 according to the present embodiment when the injection check valve 50a is in an open state. FIG. 5 is a cross-sectional view showing the injection mechanism 130 of the compressor 100 according to the present embodiment when the injection check valve 50a is in a closed state. FIG. 6 is a top view of the fixed scroll 30 of the compressor 100 according to the present embodiment. FIG. 7 is a top view of the valve plate 21 of the compressor 100 according to the present embodiment. FIG. 8 is a top view of the fixed scroll 30 to which the valve plate 21 of the compressor 100 according to the present embodiment is attached. The injection mechanism 130 included in the compressor 100 according to the first embodiment will be described with reference to FIGS. 4, 5, 6, 7, and 8.

[0046] The injection mechanism 130 is composed of the injection pipe 4, an injection pipe insertion hole 31a and a first injection flow path 131a formed in the fixed scroll 30, a second injection flow path 131b formed in the valve plate 21, a connecting flow path 131c connecting the first injection flow path 131a and the second injection flow path 131b, an injection check valve mechanism 50, an injection check valve chamber 35 in which the injection check valve mechanism 50 is housed, and an injection port 36 connecting the injection check valve chamber 35 and the compression chamber 74.

[0047] The injection pipe insertion hole 31a is an axially extending hole that opens into the fixed scroll base plate upper surface 31c. The fixed scroll base plate upper surface 31c is the surface of the fixed scroll base plate 31 opposite the surface on which the fixed scroll spiral portion 32 is formed, and is the surface on which the valve plate 21 is attached. The portion of the injection pipe insertion hole 31a that opens into the fixed scroll base plate upper surface 31c may be provided with a guide 31d whose diameter is slightly larger than that of the injection pipe insertion hole 31a to facilitate insertion of the injection pipe 4. The inner wall of the injection pipe insertion hole 31a is provided with a sealing wall surface 31e to prevent refrigerant leakage. The valve plate 21 attached to the fixed scroll base plate upper surface 31c has a through hole formed in a position that communicates with the injection pipe insertion hole 31a, through which the injection pipe 4 passes. The injection pipe 4 passes through the through hole in the valve plate 21 and is inserted into the injection pipe insertion hole 31a.

[0048] The first injection flow path 131a is a flow path for injection refrigerant formed inside the fixed scroll base plate 31 in a direction perpendicular to the axial direction, at a position where one end communicates with the injection pipe insertion hole 31a. The other end of the first injection flow path 131a communicates with a connection flow path 131c, which will be described later. The first injection flow path 131a is formed, for example, by drilling from the fixed scroll base plate outer peripheral end face 31b, which is the outer periphery of the fixed scroll base plate 31, and a hole formed in the fixed scroll base plate outer peripheral end face 31b is sealed with, for example, a bolt and packing. Note that the hole formed in the fixed scroll base plate outer peripheral end face 31b may also be sealed by applying a leak prevention agent such as a hardener to a bolt and fastening it, rather than using packing. In addition, as long as the first injection flow path 131a is formed to connect the injection pipe insertion hole 31a and the connection flow path 131c, the part of the first injection flow path 131a that communicates with the injection pipe insertion hole 31a and the connection flow path 131c does not have to be the end.

[0049] The second injection flow path 131b is a flow path for the injection refrigerant, formed by a groove formed in the lower surface of the valve plate 21, i.e., the surface that contacts the fixed scroll base plate 31 when attached to the fixed scroll base plate 31, and the upper surface 31c of the fixed scroll base plate. The groove formed in the lower surface of the valve plate 21 as the second injection flow path 131b is formed to have a semicircular or rectangular cross-sectional shape with rounded corners. However, the cross-sectional shape of the groove formed in the lower surface of the valve plate 21 as the second injection flow path 131b is not particularly limited as long as it can form a flow path for the injection refrigerant together with the upper surface 31c of the fixed scroll base plate. Forming the second injection flow path 131b using a groove in the lower surface of the valve plate 21 in this way facilitates the processing of the valve plate 21. Furthermore, the second injection flow path 131b can also be formed in a curve, etc., improving design flexibility. One end of the second injection flow path 131b communicates with a connecting flow path 131c (described later), and the other end communicates with an injection check valve chamber 35 that houses an injection check valve mechanism 50 (described later). The second injection flow path 131b is desirably formed in the valve plate 21 attached to the upper surface 31c of the fixed scroll base plate 31 so as to communicate with the upper part of the injection check valve chamber 35 formed in the fixed scroll base plate 31. Note that, as long as the second injection flow path 131b is formed to connect the connecting flow path 131c and the injection check valve chamber 35, the portion of the second injection flow path 131b that communicates with the connecting flow path 131c and the injection check valve chamber 35 does not have to be an end portion.

[0050] The connection flow passage 131c is a hole that opens to the top surface 31c of the fixed scroll base plate and extends in the axial direction. The connection flow passage 131c communicates with the end of the first injection flow passage 131a opposite to the end that communicates with the injection tube insertion hole 31a, and is formed perpendicular to the first injection flow passage 131a. Furthermore, the portion of the connection flow passage 131c that opens to the top surface 31c of the fixed scroll base plate communicates with the second injection flow passage 131b. Therefore, the connection flow passage 131c communicates with the first injection flow passage 131a and the second injection flow passage 131b, which are formed at different heights in the axial direction.

[0051] The cross-sectional areas of the first injection flow path 131a, the second injection flow path 131b, and the connecting flow path 131c are preferably the same to reduce flow path resistance. However, the cross-sectional areas of the first injection flow path 131a, the second injection flow path 131b, and the connecting flow path 131c may differ from one another as long as they can circulate the injection refrigerant.

[0052] The injection check valve chamber 35 is a space formed inside the fixed scroll base plate 31 and houses the injection check valve mechanism 50. The injection check valve chamber 35 has an upper portion which communicates with the second injection flow path 131b and a lower portion which communicates with the compression chamber 74 via the injection port 36.

[0053] The injection check valve mechanism 50 is composed of an injection check valve 50a, a spring 50b, and an injection check valve holder 51. The injection valve holder 51 prevents the injection check valve 50a from moving toward the second injection flow path 131b. The injection valve holder 51 also serves to prevent refrigerant from leaking from the outer periphery of the injection check valve 50a when the injection check valve 50a is closed. The injection check valve holder 51 can be made of either metal or non-metal, for example, carbon steel for mechanical structures. It is also desirable that the injection check valve 50a and the injection check valve holder 51 be made of the same material. The injection check valve 50a and the injection check valve holder 51 repeatedly come into contact and separate each time the injection check valve 50a opens and closes. If the injection check valve 50a and the injection check valve retainer 51 are made of different materials, the one with lower hardness will wear and be more likely to develop gaps. Therefore, by using the same material for the injection check valve 50a and the injection check valve retainer 51, wear can be reduced and the life of the injection check valve mechanism 50 can be extended. The injection check valve 50a opens and closes based on the pressure difference between the two spaces separated by the injection check valve 50a, i.e., the second injection flow path 131b and the injection check valve chamber 35. Furthermore, the injection check valve mechanism 50 may be a float valve instead of a spring type.

[0054] As long as the first injection flow path 131a and the second injection flow path 131b can be connected by the connecting flow path 131c, they may be formed in parallel, or may be formed in different directions instead of being parallel, as shown in Figures 6, 7, and 8. This increases the degree of freedom in design.

[0055] There may be a plurality of first injection flow paths 131a, second injection flow paths 131b, connecting flow paths 131c, injection check valve chambers 35, injection check valve mechanisms 50, and injection ports 36. Figures 6, 7, and 8 show examples where two of each are provided.

[0056] Next, the flow of injection refrigerant in the injection mechanism 130 will be described. As shown by the arrows in FIG. 4, when injection refrigerant flows into the injection tube 4, the injection refrigerant flows in the order of first injection flow path 131a, connection flow path 131c, and second injection flow path 131b. As the injection refrigerant flows into the second injection flow path 131b, the pressure in the second injection flow path 131b becomes higher than that in the injection check valve chamber 35, pushing down the injection check valve 50a and causing the spring 50b to contract and open. As the injection check valve 50a opens, the injection refrigerant flows from the second injection flow path 131b into the injection check valve chamber 35, passes through the injection port 36, and flows into the compression chamber 74. The refrigerant pressure in the injection check valve chamber 35 is equal to that in the compression chamber 74.

[0057] Furthermore, when no injection refrigerant is flowing into the injection pipe 4 or when the pressure of the injection refrigerant is lower than the pressure in the compression chamber 74, the injection check valve 50a is not pushed down, as shown in FIG. 5. The injection check valve 50a is pressed against the injection check valve holder 51, i.e., is in a closed state, and the injection refrigerant does not flow into the compression chamber 74. This also prevents refrigerant from flowing from the compression chamber 74 into the injection mechanism 130. If compressed refrigerant flows into the injection mechanism, this can increase noise due to refrigerant pulsation and damage to the piping. Therefore, providing the injection check valve mechanism 50 can prevent increased noise and damage to the piping.

[0058] Furthermore, when injection operation is not being performed, the injection port 36 and the injection check valve chamber 35 communicate with the compression chamber 74, resulting in dead volume. In other words, the refrigerant compressed in the compression chamber 74 leaks into the injection port 36 and the injection check valve chamber 35, causing loss due to re-expansion and reducing the performance of the compressor 100. Therefore, the dead volume can be reduced by installing the injection check valve chamber 35 directly above the compression chamber 74 into which injection is desired.

[0059] Injection operation aims to lower the discharge temperature of the compressor 100 below a protection value by injecting a relatively low-temperature refrigerant into the compression chamber 74, which is in the refrigerant compression process, when the compressor 100 discharge temperature becomes high, such as during heating operation in an environment with a low outdoor temperature. A lower temperature of the injected refrigerant allows the compressor 100 discharge temperature to be lowered below the protection value with a smaller amount of injected refrigerant. Increasing the amount of injected refrigerant increases the amount of refrigerant in the compression chamber 74, increasing the internal pressure of the compression chamber 74. This requires an increase in the torque of the drive mechanism 120, reducing the efficiency of the compressor 100. Therefore, a lower temperature of the injected refrigerant improves the operating efficiency of the compressor 100. However, before the injected refrigerant is injected into the compression chamber 74, the injection refrigerant flow path is heated by the discharge space 72, from which the compressed, high-temperature, and high-pressure refrigerant is discharged, causing the temperature to rise. 4 and 5, the second injection passage 131b through which the injection refrigerant flows is formed above the first injection passage 131a in the valve plate 21 and the fixed scroll base plate 31 to communicate with the upper part of the injection check valve chamber 35. That is, the second injection passage 131b is formed closer to the discharge space 72 than the first injection passage 131a. Therefore, by forming the second injection passage 131b, which is closer to the discharge space 72 from which the high-temperature, high-pressure refrigerant is discharged, as short as possible, it is possible to suppress a temperature rise of the injection refrigerant. In this embodiment, the first injection passage 131a is formed in the fixed scroll base plate 31, and the second injection passage 131b is formed in the valve plate 21, so the first injection passage 131a is formed below the second injection passage 131b. In other words, the first injection flow path 131a is formed at a position farther from the ejection space 72 than the second injection flow path 131b.That is, a two-stage injection flow path is formed by forming the first injection flow path 131a from the injection pipe insertion hole 31a to the vicinity of the injection check valve chamber 35, the first injection flow path 131a being farther from the discharge space 72 than the second injection flow path 131b, and communicating with the second injection flow path 131b via the connecting flow path 131c. In this way, by forming the first injection flow path 131a below the second injection flow path 131b and further forming the second injection flow path 131b which is shorter than the first injection flow path 131a, it is possible to suppress a rise in the temperature of the injection refrigerant.

[0060] As shown in FIG. 7 , a muffler 18 for noise reduction is attached to the valve plate 21, where the second injection flow path 131b is formed. The valve plate 21 also has various ports, including an overcompression relief port 34 that discharges refrigerant from the compression chamber 74 when the pressure in the compression chamber 74 exceeds a predetermined pressure, a backpressure relief port (not shown) that prevents compressor damage due to high-low pressure reversal, and a discharge port 33 that discharges compressed refrigerant. Furthermore, bolt holes for securing valves and valve guards to close each port are formed axially. Because various components are attached to the valve plate 21, there is less excess space on the valve plate 21 compared to the fixed scroll base plate 31. Therefore, it is difficult to provide the injection pipe insertion hole 31a directly above the injection check valve chamber 35 and the injection port 36 on the valve plate 21. In this embodiment, a first injection flow path 131a is formed in the fixed scroll base plate 31, which has excess space compared to the valve plate 21, from the injection pipe insertion hole 31a to the vicinity of the injection check valve chamber 35, and a two-stage injection flow path is formed in which the first injection flow path 131a communicates with the second injection flow path 131b via a connecting flow path 131c. This allows the compressor 100 to be equipped with the injection mechanism 130 provided with the injection check valve mechanism 50, without increasing the thickness of the valve plate 21 and the fixed scroll base plate 31 for the injection mechanism 130. This has the effect of allowing the compressor 100 to be made more compact.

[0061] Furthermore, the injection mechanism 130 of this embodiment forms a two-stage injection flow path in the fixed scroll base plate 31, which has excess space compared to the valve plate 21, by forming a first injection flow path 131a from the injection pipe insertion hole 31a to the vicinity of the injection check valve chamber 35 and communicating with the second injection flow path 131b via a connecting flow path 131c. This allows the injection flow paths to be formed in the fixed scroll 30 and the valve plate 21 without changing the external shapes of the shell 1, fixed scroll 30, and valve plate 21 of the compressor 100. Therefore, in order to provide the injection mechanism 130, it is not necessary to change the shell 1 and the discharge pipe 3, injection pipe 4, and suction pipe 2 connected to the shell 1 for each type of compressor 100, allowing for the use of standardized parts and resulting in cost reduction.

[0062] As described above, the compressor 100 according to the first embodiment includes: an orbiting scroll 40 having an orbiting scroll base plate 41 and an orbiting scroll spiral portion 42 formed to protrude from the orbiting scroll base plate 41; a fixed scroll base plate 31 formed with a discharge port 33 for discharging a refrigerant and an injection pipe insertion hole 31a into which an injection pipe 4 through which an injection refrigerant flows is inserted; a fixed scroll 30 having a fixed scroll spiral portion 32 formed to protrude from the fixed scroll base plate 31 and meshing with the orbiting scroll spiral portion 42 to form a compression chamber 74 communicating with the discharge port 33; and a valve plate (21) attached to the surface of the fixed scroll base plate (31) opposite to the surface on which the fixed scroll spiral portion (32) is formed. The fixed scroll base plate (31) is formed with a first injection flow path (131a) communicating with the injection pipe insertion hole (31a) and an injection check valve chamber (35) accommodating the injection check valve mechanism (50). The valve plate (21) is formed with a second injection flow path (131b) having one end communicating with the first injection flow path (131a) via a connecting flow path (131c) and the other end communicating with the injection check valve chamber (35) and being shorter than the first injection flow path (131a).

[0063] With this configuration, the second injection passage 131b, which is closer to the discharge space 72 than the first injection passage 131a, can be made shorter than the first injection passage 131a, thereby suppressing a rise in temperature of the injected refrigerant. Also, with this configuration, the compressor 100 does not need to increase the thickness of the valve plate 21 and the fixed scroll base plate 31 in order to provide the injection mechanism 130, and can be provided with the injection mechanism 130 provided with the injection check valve mechanism 50.

[0064] Furthermore, the second injection flow path 131b of the compressor 100 according to the first embodiment is formed by a groove formed in the surface of the valve plate 21 that is attached to the fixed scroll base plate 31, and the surface of the fixed scroll base plate 31 that is attached to the valve plate 21. This facilitates processing of the valve plate 21. Furthermore, the second injection flow path 131b can also be formed in a curve, etc., improving design flexibility.

[0065] Furthermore, in the compressor 100 according to the first embodiment, the first injection flow path 131a and the second injection flow path 131b communicate with each other via a connection flow path 131c that opens onto the surface of the fixed scroll base plate 31 on which the valve plate 21 is attached. This configuration makes it possible to easily communicate the first injection flow path 131a formed in the fixed scroll base plate 31 with the second injection flow path 131b formed in the valve plate 21.

[0066] Furthermore, in the compressor 100 according to the first embodiment, a sealant is provided in a portion between the valve plate 21 and the fixed scroll base plate 31, excluding the groove constituting the second injection flow path 131b and the opening of the connection flow path 131c. This configuration maintains airtightness and prevents the injection refrigerant from leaking from the second injection flow path 131b and the connection flow path 131c.

[0067] The injection check valve mechanism 50 includes an injection check valve 50a and a spring 50b. As a result, when the injection operation is performed, the injection refrigerant flows into the second injection flow path 131b and the spring 50b contracts, pushing down the injection check valve 50a attached to the spring 50b, and the refrigerant flows into the injection check valve chamber 35.

[0068] Furthermore, the injection check valve mechanism 50 further includes an injection check valve holder 51, and the injection check valve 50a and the injection check valve holder 51 are made of the same material. This reduces wear caused by the opening and closing of the injection check valve 50a, and extends the life of the injection check valve mechanism 50.

[0069] Furthermore, the refrigerant compressed by the compressor 100 according to the first embodiment includes R32. When a refrigerant including R32 is used, the discharge temperature is more likely to rise due to pressure increase by the compressor 100 compared to other refrigerants such as R410A. Therefore, by performing injection operation in the compressor 100 according to the first embodiment, the discharge temperature is lower than when injection operation is not performed, and the effect of stable operation is further enhanced.

[0070] In this embodiment, the compressor 100 is described as being equipped with a muffler 18, an over-compression relief port 34, and a back pressure relief port (not shown), but the compressor 100 does not need to be equipped with all of these.

[0071] In this embodiment, the discharge valve 22 and the over-compression relief valve 23 are described as being attached to the upper surface of the valve plate 21, but for example, the discharge valve 22 may be attached to the upper surface 31c of the fixed scroll base plate to reduce dead volume, and the over-compression relief valve 23 may be attached to the valve plate 21 to ensure space for forming the first injection flow path 131a.

[0072] In this embodiment, the connection flow path 131c is provided parallel to the axial direction, but it may be formed obliquely relative to the axial direction.

[0073] The number of first injection passages 131a and second injection passages 131b does not have to be the same. Fig. 9 is a top view of a modified example of the fixed scroll 30 to which the valve plate 21 of the compressor 100 according to the present embodiment is attached. For example, as shown in Fig. 9, one first injection passage 131a may be provided for the injection pipe insertion hole 31a, two connection passages 131c may be formed that communicate with different positions of the first injection passage 131a, and the two connection passages 131c may be connected to the second injection passages 131b, respectively.

[0074] The compressor 100 has been described as a low-pressure shell compressor in which a low-pressure refrigerant is filled in the shell 1. However, the compressor 100 is not limited to a low-pressure shell compressor, and may be a high-pressure shell compressor in which a high-pressure refrigerant is filled in the shell 1.

[0075] Embodiment 2 Next, a second embodiment will be described. The structure of the compressor 100 in this embodiment is similar to that in the first embodiment, and therefore a description thereof will be omitted. In the first embodiment, the second injection flow path 131b is formed by a groove formed in the surface of the valve plate 21 attached to the fixed scroll base plate 31 and the surface of the fixed scroll base plate 31 to which the valve plate 21 is attached. In this embodiment, the second injection flow path 131b is formed inside the valve plate 21. FIG. 10 is a cross-sectional view showing the injection mechanism 130 of the compressor 100 according to this embodiment when the injection check valve 50a is in an open state. FIG. 11 is a cross-sectional view showing the injection mechanism 130 of the compressor 100 according to this embodiment when the injection check valve 50a is in a closed state. The injection mechanism 130 provided in the compressor 100 according to the second embodiment will be described with reference to FIGS. 10 and 11.

[0076] In the present embodiment, the injection mechanism 130 is composed of the injection pipe 4, an injection pipe insertion hole 31a and a first injection flow path 131a formed in the fixed scroll 30, a second injection flow path 131b formed inside the valve plate 21, a connection flow path 131c connecting the first injection flow path 131a and the second injection flow path 131b, the injection check valve mechanism 50, the injection check valve chamber 35 in which the injection check valve mechanism 50 is housed, a second connection flow path 131d connecting the second injection flow path 131b and the injection check valve chamber 35, and an injection port 36 connecting the injection check valve chamber 35 and the compression chamber 74. The injection pipe insertion hole 31a and the first injection flow path 131a have the same configuration as in the first embodiment, and therefore description thereof will be omitted.

[0077] The second injection flow path 131b is formed inside the valve plate 21 in a direction perpendicular to the axial direction. One end of the second injection flow path 131b is connected to the connection flow path 131c, and the other end is connected to a second connection flow path 131d (described later). The second injection flow path 131b is formed, for example, by drilling from the valve plate outer peripheral end face 21a, which is the outer periphery of the valve plate 21, and a hole formed in the valve plate outer peripheral end face 21a is sealed, for example, with a bolt and packing. The hole formed in the valve plate outer peripheral end face 21a may be sealed by fastening a bolt coated with a leak prevention agent such as a hardener, instead of with a packing. As long as the second injection flow path 131b is formed to connect the connection flow path 131c and the injection check valve chamber 35, the portion of the second injection flow path 131b that communicates with the connection flow path 131c and the injection check valve chamber 35 does not have to be an end portion.

[0078] The connecting passage 131c is formed by communicating a fixed scroll base plate connecting passage 131e, which opens on the fixed scroll base plate upper surface 31c and extends in the axial direction, with a valve plate connecting passage 131f, which opens on the surface of the valve plate 21 that is attached to the fixed scroll base plate 31 and extends in the axial direction. The fixed scroll base plate connecting passage 131e formed in the fixed scroll base plate 31 communicates with an end of the first injection passage 131a opposite to the end that communicates with the injection tube insertion hole 31a, and is formed so as to intersect perpendicularly with the first injection passage 131a. The valve plate connecting passage 131f formed in the valve plate 21 is formed so as to intersect perpendicularly with the second injection passage 131b.

[0079] The second connecting passage 131d is a hole that opens on the surface of the valve plate 21 that is attached to the fixed scroll base plate 31 and communicates axially with the second injection passage 131b. When the valve plate 21 is attached to the fixed scroll base plate 31, the second connecting passage 131d communicates between the second injection passage 131b and the injection check valve chamber 35 that houses the injection check valve mechanism 50. The opening of the second connecting passage 131d is formed smaller than the outer diameter of the injection check valve 50a. As a result, when the injection check valve 50a is closed, the injection check valve 50a comes into contact with and seals the periphery of the opening of the second connecting passage 131d on the surface of the valve plate 21 that is attached to the fixed scroll base plate 31, eliminating the need for the injection check valve retainer 51. This reduces machining time and costs. In addition, in FIGS. 10 and 11, the second connection flow path 131d is provided in the axial direction, but it may be configured to be oblique.

[0080] The injection check valve chamber 35 is a space formed inside the fixed scroll base plate 31 and accommodates the injection check valve mechanism 50. The injection check valve chamber 35 has an upper portion that communicates with the second connection flow path 131d and a lower portion that communicates with the compression chamber 74 via the injection port 36.

[0081] The injection check valve mechanism 50 is composed of an injection check valve 50a and a spring 50b. The injection check valve 50a is pressed against the periphery of the opening of the second connection flow path 131d, preventing it from moving toward the second injection flow path 131b. When the injection check valve 50a is closed, the injection check valve 50a and the periphery of the opening of the second connection flow path 131d come into contact with each other, preventing refrigerant from leaking from the periphery of the injection check valve 50a. The injection check valve 50a opens and closes based on the pressure difference between the two spaces separated by the injection check valve 50a, i.e., between the second connection flow path 131d, which communicates with the second injection flow path 131b, and the injection check valve chamber 35. The injection check valve mechanism 50 may be a float valve or the like, instead of a spring type.

[0082] Next, the flow of injection refrigerant in the injection mechanism 130 will be described. As shown by the arrows in Figure 10, when injection refrigerant flows into the injection tube 4, the injection refrigerant flows in the order of first injection flow path 131a, connecting flow path 131c, and second injection flow path 131b. As the injection refrigerant flows into the second injection flow path 131b, the pressure in the second injection flow path 131b and the second connecting flow path 131d becomes higher than that in the injection check valve chamber 35, and the injection check valve 50a is pushed down and opened. The injection refrigerant flows into the injection check valve chamber 35, passes through the injection port 36, and flows into the compression chamber 74. The refrigerant pressure in the injection check valve chamber 35 is equal to the refrigerant pressure in the compression chamber 74.

[0083] Furthermore, when no injection refrigerant is flowing into the injection pipe 4 or when the pressure of the injection refrigerant is lower than the pressure of the compression chamber 74, the injection check valve 50a is not pushed down, as shown in FIG. 11. The injection check valve 50a is pressed against the peripheral portion of the opening of the second connection flow path 131d on the surface of the valve plate 21, i.e., is in a closed state, and the injection refrigerant does not flow into the compression chamber 74. Furthermore, the refrigerant can be prevented from flowing from the compression chamber 74 into the injection mechanism 130. If compressed refrigerant flows into the injection flow path, this can increase noise due to refrigerant pulsation and damage to the piping. Therefore, providing the injection check valve mechanism 50 can prevent increased noise and damage to the piping.

[0084] Because the second injection flow path 131b is not exposed on the surface of the valve plate 21, refrigerant leakage can be prevented by simply affixing a gasket 19 such as an O-ring locally to the periphery of the opening of the connecting flow path 131c of the valve plate 21, rather than placing a gasket 19 over the entire contact surface between the fixed scroll base plate upper surface 31c and the valve plate 21. Furthermore, because there is no longer a need to affix a gasket 19 over a wide area between the fixed scroll base plate 31 and the valve plate 21, it is possible to reduce the finishing precision of the fixed scroll base plate 31 and the valve plate 21, which has the effect of shortening the machining time and reducing the processing costs.

[0085] As described above, the compressor 100 according to the second embodiment includes the orbiting scroll 40 having the orbiting scroll base plate 41 and the orbiting scroll spiral portion 42 formed to protrude from the orbiting scroll base plate 41, the fixed scroll base plate 31 having the discharge port 33 for discharging the refrigerant and the injection pipe insertion hole 31a into which the injection pipe 4 through which the injection refrigerant flows is inserted, the fixed scroll 30 having the fixed scroll spiral portion 32 formed to protrude from the fixed scroll base plate 31 and meshing with the orbiting scroll spiral portion 42 to form the compression chamber 74 communicating with the discharge port 33, and .... and a valve plate (21) attached to a surface of the scroll base plate (31) opposite to the surface on which the fixed scroll scroll portion (32) is formed, the fixed scroll base plate (31) being formed with a first injection passage (131a) communicating with the injection pipe insertion hole (31a) and an injection check valve chamber (35) accommodating the injection check valve mechanism (50), and the valve plate (21) being formed with a second injection passage (131b) having one end communicating with the first injection passage via a connecting passage (131c) and the other end communicating with the injection check valve chamber (35) and being shorter than the first injection passage (131a). The second injection passage (131b) is formed inside the valve plate (21), and the connecting passage (131c) is formed to communicate with the fixed scroll base plate (31) and the valve plate (21). With this configuration, the gasket 19 for preventing refrigerant leakage provided around the opening of the connection flow path 131c can be localized, which has the effect of shortening the manufacturing time and reducing the manufacturing costs.

[0086] Embodiment 3 Next, a third embodiment will be described. In this embodiment, the structure of the compressor 100 is the same as that of the first embodiment described above, and therefore a description thereof will be omitted. In the first and second embodiments, the compressor 100 in which the valve plate 21 is attached to the upper surface 31c of the fixed scroll base plate has been described. In this embodiment, the compressor 100 does not have the valve plate 21. FIG. 12 is a cross-sectional view showing the injection mechanism of the compressor 100 according to this embodiment, with the injection check valve in an open state. FIG. 13 is a cross-sectional view showing the injection mechanism of the compressor 100 according to this embodiment, with the injection check valve in a closed state. An injection mechanism 130 provided in the compressor 100 according to the third embodiment will be described with reference to FIGS. 12 and 13.

[0087] In this embodiment, a muffler 18 for noise reduction is attached to the fixed scroll base plate 31. The fixed scroll base plate 31 also has various ports, including an overcompression relief port 34 that discharges refrigerant from the compression chamber 74 when the pressure in the compression chamber 74 exceeds a predetermined pressure, a backpressure relief port (not shown) that prevents compressor damage due to a high-low pressure reversal, and a discharge port 33 that discharges compressed refrigerant. Furthermore, bolt holes for securing valves and valve guards for closing each port are formed axially. Thus, various components are attached to the fixed scroll base plate 31. In particular, there is less excess space inside the upper portion of the fixed scroll base plate 31 than inside the lower portion due to the provision of bolt holes and other features. Therefore, a first injection flow path 131a is formed in the lower part inside the fixed scroll base plate 31 where there is relatively more space, and a two-stage injection flow path is formed that connects to a second injection flow path 131b, which is shorter than the first injection flow path 131a, above the first injection flow path 131a via a connecting flow path 131c.

[0088] The injection mechanism 130 is composed of the injection tube 4, the injection tube insertion hole 31a and the first injection flow path 131a, the second injection flow path 131b, a connecting flow path 131c connecting the first injection flow path 131a and the second injection flow path 131b, the injection check valve mechanism 50, the injection check valve chamber 35 in which the injection check valve mechanism 50 is housed, a second connecting flow path 131d connecting the second injection flow path 131b and the injection check valve chamber 35, and the injection port 36 connecting the injection check valve chamber 35 and the compression chamber 74. In this embodiment, all of the components of the injection mechanism 130 are formed on the fixed scroll base plate 31.

[0089] The injection tube insertion hole 31a is a hole that opens into the upper surface 31c of the fixed scroll base plate and extends in the axial direction. The upper surface 31c of the fixed scroll base plate is the surface of the fixed scroll base plate 31 opposite to the surface on which the fixed scroll spiral portion 32 is formed. A guide 31d with a diameter slightly larger than that of the injection tube insertion hole 31a may be provided at the portion of the injection tube insertion hole 31a that opens into the upper surface 31c of the fixed scroll base plate to facilitate insertion of the injection tube 4. A sealing wall surface 31e is provided on the inner wall of the injection tube insertion hole 31a to prevent refrigerant leakage.

[0090] The first injection flow path 131a is a flow path for injection refrigerant formed inside the fixed scroll base plate 31 in a direction perpendicular to the axial direction, at a position where one end communicates with the injection pipe insertion hole 31a. The other end of the first injection flow path 131a communicates with a connection flow path 131c, which will be described later. The first injection flow path 131a is formed, for example, by drilling from the fixed scroll base plate outer peripheral end face 31b, which is the outer periphery of the fixed scroll base plate 31, and a hole formed in the fixed scroll base plate outer peripheral end face 31b is sealed with, for example, a bolt and packing. Note that the hole formed in the fixed scroll base plate outer peripheral end face 31b may also be sealed by applying a leak prevention agent such as a hardener to a bolt and fastening it, rather than using packing. In addition, as long as the first injection flow path 131a is formed to connect the injection pipe insertion hole 31a and the connection flow path 131c, the part of the first injection flow path 131a that communicates with the injection pipe insertion hole 31a and the connection flow path 131c does not have to be the end.

[0091] The second injection flow path 131b is a flow path for injection refrigerant formed inside the fixed scroll base plate 31 in the axial direction and perpendicular to the axial direction, higher than the first injection flow path 131a. One end of the second injection flow path 131b communicates with a connecting flow path 131c (described later), and the other end communicates with an injection check valve chamber 35 (described later) that houses an injection check valve mechanism 50. The second injection flow path 131b is formed, for example, by drilling from the fixed scroll base plate outer peripheral end face 31b, which is the outer periphery of the fixed scroll base plate 31, and a hole formed in the fixed scroll base plate outer peripheral end face 31b is sealed, for example, with a bolt and packing. The hole formed in the fixed scroll base plate outer peripheral end face 31b may also be sealed by applying a leak prevention agent such as a hardener to a bolt and fastening it, rather than with a packing. Furthermore, as long as the second injection flow path 131b is formed to connect the connection flow path 131c and the injection check valve chamber 35, the part of the second injection flow path 131b that communicates with the connection flow path 131c and the injection check valve chamber 35 does not have to be the end.

[0092] The connection flow path 131c communicates between the first injection flow path 131a and the second injection flow path 131b. One end of the connection flow path 131c communicates with the end of the first injection flow path 131a opposite the end that communicates with the injection tube insertion hole 31a. The other end of the connection flow path 131c communicates with the second injection flow path 131b. The connection flow path 131c is formed, for example, by drilling from the top surface 31c of the fixed scroll base plate, and the hole in the top surface 31c of the fixed scroll base plate is sealed, for example, with a bolt and packing. Note that the hole in the top surface 31c of the fixed scroll base plate may also be sealed by applying a leak prevention agent such as a hardener to a bolt and fastening it, rather than with a packing.

[0093] The cross-sectional areas of the first injection flow path 131a, the second injection flow path 131b, and the connecting flow path 131c are preferably the same to reduce flow path resistance. However, the cross-sectional areas of the first injection flow path 131a, the second injection flow path 131b, and the connecting flow path 131c may differ from one another as long as they can circulate the injection refrigerant.

[0094] The second connection flow path 131d is an axially extending hole that connects the second injection flow path 131b with the injection check valve chamber 35 that houses the injection check valve mechanism 50. The opening of the second connection flow path 131d that connects with the injection check valve chamber 35 is formed to be smaller than the outer diameter of the injection check valve 50a. As a result, when the injection check valve 50a is closed, the injection check valve 50a and the upper wall surface of the injection check valve chamber 35 come into contact and form a seal, eliminating the need for the injection check valve retainer 51. Note that although the second connection flow path 131d is provided in the axial direction in FIGS. 12 and 13, it may also be configured to be oblique.

[0095] The injection check valve chamber 35 is a space formed inside the fixed scroll base plate 31 and accommodates the injection check valve mechanism 50. The injection check valve chamber 35 has an upper portion communicating with the second connection flow path 131d and a lower portion communicating with the compression chamber 74 via the injection port 36.

[0096] The injection check valve mechanism 50 is composed of an injection check valve 50a and a spring 50b. The injection check valve 50a is pressed against the upper wall surface of the injection check valve chamber 35, preventing it from moving toward the second injection flow path 131b. When the injection check valve 50a is closed, the injection check valve 50a comes into contact with the upper wall surface of the injection check valve chamber 35, preventing refrigerant from leaking from the outer periphery of the injection check valve 50a. The injection check valve 50a opens and closes based on the pressure difference between the two spaces separated by the injection check valve 50a, i.e., between the second connection flow path 131d communicating with the second injection flow path 131b and the injection check valve chamber 35. The injection check valve mechanism 50 does not need to be spring-type, and may instead be a float valve or the like.

[0097] Next, the flow of injection refrigerant in the injection mechanism 130 will be described. As shown by the arrows in Figure 12, when injection refrigerant flows into the injection tube 4, the injection refrigerant flows in the order of first injection flow path 131a, connecting flow path 131c, and second injection flow path 131b. As the injection refrigerant flows into the second injection flow path 131b, the pressure in the second injection flow path 131b and the second connecting flow path 131d becomes higher than that in the injection check valve chamber 35, and the injection check valve 50a is pushed down and opened. The injection refrigerant flows into the injection check valve chamber 35, passes through the injection port 36, and flows into the compression chamber 74. The refrigerant pressure in the injection check valve chamber 35 is equal to the refrigerant pressure in the compression chamber 74.

[0098] Furthermore, when no injection refrigerant is flowing into the injection pipe 4 or when the pressure of the injection refrigerant is lower than the pressure of the compression chamber 74, the injection check valve 50a is not pushed down, as shown in FIG. 13. The injection check valve 50a is pressed against the upper wall surface of the injection check valve chamber 35, i.e., is in a closed state, and the injection refrigerant does not flow into the compression chamber 74. This also prevents refrigerant from flowing from the compression chamber 74 into the injection mechanism 130. If compressed refrigerant flows into the injection mechanism, this can increase noise due to refrigerant pulsation and damage to the piping. Therefore, providing the injection check valve mechanism 50 can prevent increased noise and damage to the piping.

[0099] In this way, a two-stage injection flow path is formed in which the first injection flow path 131a is formed in the lower part inside the fixed scroll base plate 31 where there is relatively more space, and which communicates with the second injection flow path 131b, which is shorter than the first injection flow path 131a and is located above the first injection flow path 131a, via the connecting flow path 131c. As a result, even in a compressor 100 that does not have a valve plate 21, it is not necessary to increase the size of the fixed scroll base plate 31 for the injection mechanism 130, and the injection mechanism 130 provided with the injection check valve mechanism 50 can be provided.

[0100] As described above, the compressor 100 according to the third embodiment includes the orbiting scroll 40 having the orbiting scroll base plate 41 and the orbiting scroll spiral portion 42 formed to protrude from the orbiting scroll base plate 41, the fixed scroll base plate 31 having the discharge port 33 for discharging the refrigerant and the injection pipe insertion hole 31a into which the injection pipe 4 through which the injection refrigerant flows is inserted, and the fixed scroll spiral portion 32 formed to protrude from the fixed scroll base plate 31 and meshing with the orbiting scroll spiral portion 42 to form the compression chamber 74 communicating with the discharge port 33. and a fixed scroll 30 having an injection pipe insertion hole 31a, and the fixed scroll base plate 31 is formed with a first injection flow path 131a communicating with the injection pipe insertion hole 31a, an injection check valve chamber 35 communicating with the compression chamber and accommodating the injection check valve mechanism 50, and a second injection flow path 131b having one end communicating with the first injection flow path 131a via a connecting flow path 131c and the other end communicating with the injection check valve chamber 35, the second injection flow path 131b being shorter than the first injection flow path 131a and located farther from the compression chamber 74 than the first injection flow path 131a. With this configuration, even in a compressor 100 that does not have a valve plate 21, a two-stage injection flow path can be formed in which a long first injection flow path 131a is formed in the lower part inside the fixed scroll base plate 31 where there is relatively more space, and which communicates with a second injection flow path 131b that is shorter than the first injection flow path 131a in the upper part, thereby suppressing a rise in temperature of the injected refrigerant. Furthermore, the compressor 100 does not need to increase the size of the fixed scroll base plate 31 for the injection mechanism 130, and can be provided with an injection mechanism 130 that is provided with an injection check valve mechanism 50.

[0101] Embodiment 4 Next, a fourth embodiment will be described. In this embodiment, the structure of the compressor 100 is the same as that of the first embodiment described above, and therefore a description thereof will be omitted. In the first, second, and third embodiments, the injection check valve mechanism 50 is of a spring type. In this embodiment, a reed valve 50c is used as the injection check valve mechanism 50. Fig. 14 is a cross-sectional view showing the injection mechanism 130 of the compressor 100 according to this embodiment when the reed valve 50c is in an open state. Fig. 15 is a cross-sectional view showing the injection mechanism 130 of the compressor 100 according to this embodiment when the reed valve 50c is in a closed state. The injection mechanism 130 provided in the compressor 100 according to the fourth embodiment will be described with reference to Figs. 14 and 15.

[0102] In this embodiment, the injection mechanism 130 is composed of the injection pipe 4, an injection pipe insertion hole 31a and a first injection passage 131a formed in the fixed scroll 30, a second injection passage 131b formed inside the valve plate 21, a connecting passage 131c connecting the first injection passage 131a and the second injection passage 131b, the injection check valve mechanism 50, the injection check valve chamber 35 in which the injection check valve mechanism 50 is housed, a second connecting passage 131d connecting the second injection passage 131b and the injection check valve chamber 35, and an injection port 36 connecting the injection check valve chamber 35 and the compression chamber 74. The injection pipe insertion hole 31a, the first injection flow path 131a, the second injection flow path 131b, the connection flow path 131c, the second connection flow path 131d, and the injection check valve chamber 35 have the same configuration as in the second embodiment, and therefore description thereof will be omitted.

[0103] The injection check valve mechanism 50 is composed of a reed valve 50c, a reed valve holder 50d, and a reed valve fixing tool 51e.

[0104] The reed valve 50c is a thin, elastic plate, one end of which is fixed to the valve plate 21 by a reed valve fixture 51e. The reed valve fixture 51e is, for example, a bolt. In the closed state, the end of the reed valve 50c that is not fixed by the reed valve fixture 51e comes into contact with the periphery of the opening of the second connection flow path 131d in the valve plate 21, blocking the opening of the second connection flow path 131d. In the open state, the pressure of the injected refrigerant causes the end of the reed valve 50c that is not fixed by the reed valve fixture 51e to elastically deform downward. This allows the injected refrigerant to flow into the injection check valve chamber 35 from the opening of the second connection flow path 131d.

[0105] The reed valve holder 50d comes into contact with the reed valve 50c when the reed valve 50c is elastically deformed by the pressure of the injected refrigerant, preventing the reed valve 50c from bending excessively. Specifically, one end of the reed valve holder 50d is fixed to the valve plate 21 together with the reed valve 50c by a reed valve fixing device 51e. The end of the reed valve holder 50d that is not fixed by the reed valve fixing device 51e is positioned below the unfixed end of the reed valve 50c. When the reed valve 50c is not elastically deformed, the gap between the reed valve 50c and the reed valve holder 50d gradually widens from the fixed end to the unfixed end. This prevents the reed valve 50c from bending excessively when the reed valve 50c is elastically deformed by the pressure of the injected refrigerant discharged from the opening of the second connection flow path 131d.

[0106] Next, the flow of injection refrigerant in the injection mechanism 130 will be described. As shown by the arrows in Figure 14, when injection refrigerant flows into the injection tube 4, the injection refrigerant flows in the order of the first injection flow path 131a, the connecting flow path 131c, and the second injection flow path 131b. As the injection refrigerant flows into the second injection flow path 131b, the pressure in the second injection flow path 131b and the second connecting flow path 131d becomes higher than that in the injection check valve chamber 35, and the unfixed end of the reed valve 50c is pressed down and opened. The injection refrigerant flows into the injection check valve chamber 35, passes through the injection port 36, and flows into the compression chamber 74. The refrigerant pressure in the injection check valve chamber 35 is equal to that in the compression chamber 74.

[0107] Furthermore, when no injection refrigerant is flowing into the injection tube 4 or when the pressure of the injection refrigerant is lower than the pressure in the compression chamber 74, the unfixed end of the reed valve 50c blocks the opening of the second connection flow path 131d. Therefore, as shown by the arrow in FIG. 15, refrigerant does not flow into the second connection flow path 131d, preventing compressed refrigerant from flowing into the injection flow path. If compressed refrigerant flows into the injection mechanism, refrigerant pulsation can increase noise and damage the piping. Therefore, providing the injection check valve mechanism 50 can prevent increased noise and damage to the piping.

[0108] If a spring-type check valve is used in the injection check valve mechanism 50, a sufficient stroke length for the spring 50b is required, necessitating a length in the valve element movement direction. Therefore, if the valve movement direction is set axially as in the first to third embodiments, the fixed scroll base plate 31 must be thick to accommodate the injection check valve mechanism 50. By using a reed valve 50c in the injection check valve mechanism 50, the required axial height can be reduced compared to a spring-type mechanism, allowing the fixed scroll base plate 31 to be thinner. This reduces material costs and enables cost reductions. Furthermore, the thinner fixed scroll base plate 31 allows the valve plate 21 to be mounted lower within the shell 1, thereby expanding the discharge space 72 of the compressor 100. Refrigerant compressed by the orbiting scroll 40 and the fixed scroll 30 is discharged into the discharge space 72 of the compressor 100 through the discharge port 33 formed in the fixed scroll 30. The discharge space 72 serves as a buffer space for the discharged refrigerant and acts as a muffler to suppress noise caused by the valve opening and closing. Therefore, the discharge space 72, which is a buffer space for the refrigerant, is enlarged, and noise can be reduced without providing the muffler 18 in the compressor 100.

[0109] As described above, the compressor 100 according to the fourth embodiment includes the orbiting scroll 40 having the orbiting scroll base plate 41 and the orbiting scroll spiral portion 42 formed to protrude from the orbiting scroll base plate 41, the fixed scroll base plate 31 having the discharge port 33 for discharging the refrigerant and the injection pipe insertion hole 31a into which the injection pipe 4 through which the injection refrigerant flows is inserted, the fixed scroll 30 having the fixed scroll spiral portion 32 formed to protrude from the fixed scroll base plate 31 and meshing with the orbiting scroll spiral portion 42 to form the compression chamber 74 communicating with the discharge port 33, and the fixed scroll 30 having the fixed scroll spiral portion 32 formed to protrude from the fixed scroll base plate 31. and a valve plate (21) attached to the surface of the scroll base plate (31) opposite the surface on which the fixed scroll scroll portion (32) is formed. The fixed scroll base plate (31) is formed with a first injection passage (131a) communicating with the injection pipe insertion hole (31a) and an injection check valve chamber (35) accommodating an injection check valve mechanism (50). The valve plate (21) is formed with a second injection passage (131b) having one end communicating with the first injection passage via a connecting passage (131c) and the other end communicating with the injection check valve chamber (35), the second injection passage (131b) being shorter than the first injection passage (131a). The injection check valve mechanism (50) is further characterized by including a reed valve (50c). By using the reed valve (50c) in the injection check valve mechanism (50), the height of the injection check valve chamber (35) can be reduced.

[0110] The injection check valve chamber 35 that houses the injection check valve mechanism 50 may be provided in the valve plate 21. Fig. 16 is a cross-sectional view showing a modified example of the injection mechanism 130 of the compressor 100 according to the present embodiment. As shown in Fig. 16, if space can be secured below the second injection flow path 131b and the second connection flow path 131d formed in the valve plate 21, the injection check valve chamber 35 may be provided in the valve plate 21.

[0111] The configurations shown in the above embodiments are examples of the content of the present invention, and may be combined with other known technologies, and some of the configurations may be omitted or modified within the scope of the gist of the present invention.

[0112] Examples of aspects that may be included in the present disclosure are set forth below as appendices. (Appendix 1) an orbiting scroll having an orbiting scroll base plate and an orbiting scroll spiral portion formed to protrude from the orbiting scroll base plate; a fixed scroll base plate formed with a discharge port for discharging a refrigerant and an injection pipe insertion hole into which an injection pipe through which an injection refrigerant flows is inserted; and a fixed scroll having a fixed scroll spiral portion formed to protrude from the fixed scroll base plate and meshing with the orbiting scroll spiral portion to form a compression chamber communicating with the discharge port; a valve plate attached to a surface of the fixed scroll base plate opposite to a surface on which the fixed scroll spiral portion is formed, the fixed scroll base plate is formed with a first injection flow passage communicating with the injection pipe insertion hole, and an injection check valve chamber communicating with the compression chamber and accommodating an injection check valve mechanism; The valve plate has one end communicating with the first injection flow path and the other end communicating with the injection check valve chamber, and a second injection flow path that is shorter than the first injection flow path is formed in the valve plate. (Appendix 2) The compressor described in Appendix 1, wherein the second injection flow path is formed by a groove formed in a surface of the valve plate that is attached to the fixed scroll base plate and a surface of the fixed scroll base plate that is attached to the valve plate. (Appendix 3) The compressor according to claim 2, wherein the first injection passage and the second injection passage are connected to each other via a connecting passage formed in a surface of the fixed scroll base plate on which the valve plate is attached. (Appendix 4) 4. The compressor according to claim 3, wherein a sealing material is provided between the valve plate and the fixed scroll base plate, except for the groove that constitutes the second injection flow path and the opening of the connecting flow path. (Appendix 5) 2. The compressor according to claim 1, wherein the second injection passage is formed inside the valve plate. (Appendix 6) an orbiting scroll having an orbiting scroll base plate and an orbiting scroll spiral portion formed to protrude from the orbiting scroll base plate; a fixed scroll base plate formed with a discharge port for discharging a refrigerant and an injection pipe insertion hole into which an injection pipe through which an injection refrigerant flows is inserted; and a fixed scroll having a fixed scroll spiral portion formed to protrude from the fixed scroll base plate and meshing with the orbiting scroll spiral portion to form a compression chamber that communicates with the discharge port, the fixed scroll base plate is formed with a first injection passage communicating with the injection pipe insertion hole, an injection check valve chamber communicating with the compression chamber and accommodating an injection check valve mechanism, and a second injection passage having one end communicating with the first injection passage and the other end communicating with the injection check valve chamber, the second injection passage being shorter than the first injection passage and located farther from the compression chamber than the first injection passage. (Appendix 7) 7. The compressor according to claim 1, wherein the injection check valve mechanism comprises an injection check valve and a spring. (Appendix 8) The compressor according to any one of appendixes 2 to 4, wherein the injection check valve mechanism is composed of an injection check valve, a spring, and an injection check valve holder, and the injection check valve and the injection check valve holder are made of the same material. (Appendix 9) 7. The compressor according to claim 1, wherein the injection check valve mechanism is a reed valve. (Appendix 10) 10. The compressor according to any one of claims 1 to 9, wherein the refrigerant includes R32. [Explanation of symbols]

[0113] 1 shell, 1a upper shell, 1b middle shell, 1c lower shell, 2 suction pipe, 3 discharge pipe, 4 injection pipe, 4a injection pipe insertion portion, 5 oil reservoir, 6 frame, 6a thrust bearing, 6b Oldham receiving portion, 6c frame Oldham groove, 6d frame boss, 6e main bearing portion, 6f boss receiving portion, 7 shaft, 7a eccentric shaft portion, 7b main shaft portion, 7c counter shaft portion, 7d shaft oil supply hole, 8 subframe, 8a counter bearing receiving portion, 8b counter bearing, 10 oil pump, 11 Oldham ring, 11a Oldham ring upper claw, 11b Oldham ring lower claw, 12 slider, 13 sleeve, 14 seal member, 15 stator, 16 rotor, 17 face seal, 18 muffler, 19 gasket, 21 valve plate, 21a Valve plate outer peripheral end surface, 22 discharge valve, 22a discharge valve retainer, 23 over-compression relief valve, 23a over-compression relief valve retainer, 24 valve plate back groove, 30 fixed scroll, 31 fixed scroll base plate, 31a injection tube insertion hole, 31b fixed scroll base plate outer peripheral end surface, 31c fixed scroll base plate upper surface, 31d guide, 31e seal wall surface, 32 fixed scroll spiral portion, 33 discharge port, 34 over-compression relief port, 35 injection check valve chamber, 36 injection port, 40 orbiting scroll, 41 orbiting scroll base plate, 42 orbiting scroll spiral portion, 43 orbiting scroll boss, 43a orbiting bearing portion, 44 thrust surface, 45 orbiting scroll base plate Oldham groove, 50 injection check valve mechanism, 50a injection check valve, 50b spring, 50c Reed valve, 50d reed valve retainer, 51 injection check valve retainer, 71 suction space, 72 discharge space, 73 volute suction space, 74 compression chamber, 100 compressor, 110 compression mechanism, 120 drive mechanism, 130 injection mechanism, 131a first injection flow path, 131b second injection flow path, 131c connecting flow path, 131d second connecting flow path, 200 refrigerant circuit, 201 condenser, 202 expansion device, 203 evaporator, 204 expansion valve, 205 refrigerant piping, 205a refrigerant piping for injection.

Claims

1. an orbiting scroll having an orbiting scroll base plate and an orbiting scroll spiral portion formed to protrude from the orbiting scroll base plate; a fixed scroll base plate formed with a discharge port for discharging a refrigerant and an injection pipe insertion hole into which an injection pipe through which an injection refrigerant flows is inserted; and a fixed scroll having a fixed scroll spiral portion formed to protrude from the fixed scroll base plate and meshing with the orbiting scroll spiral portion to form a compression chamber communicating with the discharge port; a valve plate attached to a surface of the fixed scroll base plate opposite to a surface on which the fixed scroll spiral portion is formed, the fixed scroll base plate is formed with a first injection flow passage communicating with the injection pipe insertion hole, and an injection check valve chamber communicating with the compression chamber and accommodating an injection check valve mechanism, a second injection passage formed in the valve plate, the second injection passage having one end communicating with the first injection passage and the other end communicating with the injection check valve chamber, the second injection passage being shorter than the first injection passage;

2. 2. The compressor according to claim 1, wherein the second injection passage is formed by a groove formed in a surface of the valve plate that is attached to the fixed scroll base plate and a surface of the fixed scroll base plate that is attached to the valve plate.

3. 3. The compressor according to claim 2, wherein the first injection passage and the second injection passage communicate with each other through a connecting passage formed in a surface of the fixed scroll base plate on which the valve plate is attached.

4. 4. The compressor according to claim 3, wherein a seal is provided between the valve plate and the fixed scroll base plate, except for the groove that forms the second injection passage and the opening of the connecting passage.

5. The compressor according to claim 1 , wherein the second injection passage is formed inside the valve plate.

6. an orbiting scroll having an orbiting scroll base plate and an orbiting scroll spiral portion formed to protrude from the orbiting scroll base plate; a fixed scroll base plate formed with a discharge port for discharging a refrigerant and an injection pipe insertion hole into which an injection pipe through which an injection refrigerant flows is inserted; and a fixed scroll having a fixed scroll spiral portion formed to protrude from the fixed scroll base plate and meshing with the orbiting scroll spiral portion to form a compression chamber that communicates with the discharge port, the fixed scroll base plate is formed with a first injection passage communicating with the injection pipe insertion hole, an injection check valve chamber communicating with the compression chamber and accommodating an injection check valve mechanism, and a second injection passage having one end communicating with the first injection passage and the other end communicating with the injection check valve chamber, the second injection passage being shorter than the first injection passage and located farther from the compression chamber than the first injection passage.

7. 7. The compressor according to claim 1, wherein the injection check valve mechanism comprises an injection check valve and a spring.

8. 5. The compressor according to claim 2, wherein the injection check valve mechanism includes an injection check valve, a spring, and an injection check valve holder, and the injection check valve and the injection check valve holder are made of the same material.

9. 7. The compressor according to claim 1, wherein the injection check valve mechanism comprises a reed valve.

10. The compressor according to any one of claims 1 to 6, wherein the refrigerant includes R32.

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