Electric compressor

Abstract

To enhance support of an injection pipe by an electric compressor.SOLUTION: An electric compressor (50) includes: a motor housing (60) including a motor chamber (61) which houses a motor (100); a rear head (70) including an intermediate pressure chamber (71) which houses a two stage compression mechanism (110); and a partition block (80) which is sandwiched between the motor housing (60) and the rear head (70) and partitions the motor chamber (61) from the intermediate pressure chamber (71). The partition block (80) includes: an injection inlet (151) through which an injection gas refrigerant may be introduced; an injection outlet (152) through which the injection gas refrigerant may be led out into the intermediate pressure chamber (71); and an injection passage (153) which allows the injection inlet (151) and the injection outlet (152) to communicate with each other.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an improved technique for an electric compressor that includes a compression mechanism that compresses a refrigerant in two stages and a motor that drives the compression mechanism. [Background technology]

[0002] Among electric compressors, there is a rolling piston type rotary compressor that performs two-stage compression, has an intermediate pressure chamber around the compression mechanism, and injects intermediate pressure refrigerant from an air conditioner circuit into the intermediate pressure chamber. For example, the technology of Patent Document 1 is known as an example of such an electric compressor.

[0003] According to the technology known from Patent Document 1, a low-stage compressor is disposed below a motor inside a housing, and a high-stage compressor is disposed below the low-stage compressor, which is a so-called vertically mounted electric compressor. The inside of the housing is partitioned by a partition member into a first sealed chamber that houses the motor and a second sealed chamber that houses the compression mechanism.

[0004] The injection pipe for the intermediate-pressure refrigerant is provided in the housing and is connected to the second sealed chamber. Therefore, the second sealed chamber is configured to be in an intermediate-pressure atmosphere. The suction passage of the low-stage compression mechanism communicates with the first sealed chamber. The discharge passage of the low-stage compression mechanism opens to the second sealed chamber. The suction passage of the high-stage compression mechanism communicates with the second sealed chamber. The discharge passage of the high-stage compression mechanism communicates with a discharge pipe for the high-pressure refrigerant. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-054975 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, since vehicle air conditioners are exposed to high refrigerant pressures caused by vehicle vibrations and high temperatures under the blazing sun, they are required to have extremely strict reliability. Therefore, if the injection pipe is formed to penetrate the housing wall, the support for the injection pipe becomes weak, and there is a risk that the reliability requirements cannot be met.

[0007] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a technique that can strengthen the support of an injection pipe by an electric compressor. [Means for solving the problem]

[0008] In the following description, reference numerals in the accompanying drawings are placed in parentheses to facilitate understanding of the present invention, but the present invention is not limited to the illustrated form.

[0009] According to the present invention, in an electric compressor (50) including a two-stage compression mechanism (110) having a low-stage side compressor (120) and a high-stage side compressor (130), a motor (100) that drives the two-stage compression mechanism (110), a motor housing (60) that includes a motor chamber (61) that houses the motor (100), a rear head (70) that includes an intermediate pressure chamber (71) that houses the two-stage compression mechanism (110), and a partition block (80) that is sandwiched between the rear head (70) and the motor housing (60) and that separates the motor chamber (61) from the intermediate pressure chamber (71), The partition block (80) is provided with an injection inlet (151) through which an injection gas refrigerant can be introduced, an injection outlet (152) through which the injection gas refrigerant can be discharged to the intermediate pressure chamber (71), and an injection passage (153) connecting the injection inlet (151) and the injection outlet (152).

[0010] Preferably, a check valve (160) is arranged at the injection outlet (152) for allowing the injection gas refrigerant to flow only from the injection passage (153) to the intermediate pressure chamber (71).

[0011] More preferably, the injection outlet (152) and the check valve (160) are provided on a flat surface (82) of the partition block (80) facing the intermediate pressure chamber (71).

[0012] Preferably, the check valve (160) comprises a reed valve (161).

[0013] More preferably, the partition block (80) has a suction passage (84) therein, which connects the motor chamber (61) with the suction port (125a) of the low-stage compressor (120).

[0014] In another preferred example, the partition block (80) is integrally provided with a shaft support portion (83) for supporting the rotating shaft (101) of the two-stage compression mechanism (110). Effect of the Invention

[0015] According to the present invention, the injection pipe can be firmly supported by the electric compressor. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1A is a conceptual diagram showing one example of an injection type refrigeration cycle according to an embodiment, and FIG. 1B is a conceptual diagram showing another example of an injection type refrigeration cycle according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the electric compressor shown in FIG. [Diagram 3] 3 is an enlarged view of the two-stage compression mechanism and its surroundings shown in FIG. 2. [Figure 4] 4 is a cross-sectional view of the low-stage compressor shown in FIG. 3 as viewed from the axial direction of a motor shaft. [Diagram 5]4 is a cross-sectional view of the high-stage compressor shown in FIG. 3 as viewed from the axial direction of a motor shaft. [Figure 6] FIG. 4 is a cross-sectional view of the vicinity of an injection inlet in the partition block shown in FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Note that the embodiments shown in the accompanying drawings are merely examples of the present invention, and the present invention is not limited to these embodiments.

[0018] <Example> An electric compressor 50 according to an embodiment and injection type refrigeration cycles 10, 30 including the electric compressor 50 will be described with reference to Figs.

[0019] 1A shows an example of an injection type refrigeration cycle 10 (hereinafter, abbreviated as "refrigeration cycle 10"). This refrigeration cycle 10 is used, for example, in an automobile air conditioner, and performs cooling and heating by an interior air conditioning unit (not shown). Note that the use of this refrigeration cycle 10 is not limited. In addition, this refrigeration cycle 10 is suitable for use with R744 refrigerant, but other refrigerants (for example, R134a refrigerant and R1234yf refrigerant) can be used.

[0020] Here, the injection type refers to a system in which the refrigeration cycle 10 expands a high-pressure refrigerant in two stages and returns the intermediate-pressure gas refrigerant (gas-phase refrigerant) separated into gas and liquid to the electric compressor 50. This intermediate-pressure gas refrigerant returned to the electric compressor 50 is called an injection gas refrigerant.

[0021] More specifically, the refrigeration cycle 10 includes an evaporator 11, a gas cooler 12, a first expansion valve 13, a second expansion valve 14, a gas-liquid separator 15, and an electric compressor 50.

[0022] The electric compressor 50 includes a two-stage compression mechanism 110. The two-stage compression mechanism 110 has a low-stage side compressor 120 and a high-stage side compressor 130. The electric compressor 50 further includes a suction port 68 capable of drawing in a refrigerant from the outside (evaporator 11), a discharge port 75 capable of discharging the refrigerant to the outside (gas cooler 12), and an injection inlet 151 capable of introducing an injection gas refrigerant.

[0023] A refrigerant outlet of the gas cooler 12 is connected to a refrigerant inlet of a gas-liquid separator 15 via a first expansion valve 13 through a first flow path 21. A refrigerant outlet of the gas-liquid separator 15 is connected to an injection pipe 22 through which an injection gas refrigerant flows and a second flow path 23 through which a liquid refrigerant flows. The injection pipe 22 is connected to an injection inlet 151 of the electric compressor 50.

[0024] The second flow path 23 is connected to the refrigerant inlet of the evaporator 11 via the second expansion valve 14. The refrigerant outlet of the evaporator 11 is connected to the suction port 68 of the electric compressor 50 via the third flow path 24. The discharge port 75 of the electric compressor 50 is connected to the refrigerant inlet of the gas cooler 12 via the fourth flow path 25.

[0025] 1A. That is, the refrigerant that has exchanged heat with the outside air by the gas cooler 12 flows through the first flow path 21, the first expansion valve 13, the gas-liquid separator 15, the second expansion valve 14, and the evaporator 11 to the suction port 68 of the electric compressor 50, where it is compressed to a high pressure. The refrigerant compressed to a high pressure by the electric compressor 50 flows through the fourth flow path 25 to the gas cooler 12.

[0026] In this way, the refrigerant that has exchanged heat with the outside air by the gas cooler 12 is rapidly adiabatically expanded by the first expansion valve 13 and the second expansion valve 14, and then returns to the evaporator 11. In other words, the refrigerant that has left the gas cooler 12 is expanded in two stages by the first expansion valve 13 and the second expansion valve 14.

[0027] The intermediate-pressure refrigerant that has passed only through the first expansion valve 13 of the two expansion valves 13, 14 passes through the gas-liquid separator 15 and flows to the injection inlet 151 of the electric compressor 50 via the injection pipe 22. By appropriately adjusting the openings of the first expansion valve 13 and the second expansion valve 14 in accordance with operating requirements, the amount branched to the injection inlet 151 of the compressor 50 can be adjusted.

[0028] 1B shows another example of an injection type refrigeration cycle 30 (hereinafter, abbreviated as "refrigeration cycle 30"). In this other example of the refrigeration cycle 30, an internal heat exchanger 31 is provided instead of the gas-liquid separator 15 of the refrigeration cycle 10. A refrigerant outlet of the gas cooler 12 is connected to a refrigerant inlet of the internal heat exchanger 31 by a first flow path 21. A portion 21a between the gas cooler 12 and the internal heat exchanger 31, i.e., a branch point 21a, of the first flow path 21 is branched by a branch path 41 and is connected to an inlet of the internal heat exchanger 31 via a first expansion valve 13. An outlet of the internal heat exchanger 31 is connected to an injection inlet 151 of the electric compressor 50 by an injection pipe 22.

[0029] In another example of the refrigeration cycle 30, the refrigerant branched from the branch point 21a between the gas cooler 12 and the internal heat exchanger 31 is adiabatically expanded by the first expansion valve 13, and then heated by the internal heat exchanger 31. The heated gas refrigerant is then passed through the injection pipe 22 to the injection inlet 151 of the electric compressor 50.

[0030] Next, the overall configuration of the electric compressor 50 will be described. 2, this electric compressor 50 has a configuration of a so-called horizontally placed electric compressor in which, for example, a two-stage compression mechanism 110 is disposed beside a motor 100. This electric compressor 50 includes a housing 51, the motor 100, and the two-stage compression mechanism 110 driven by the motor 100.

[0031] The housing 51 is configured to be installed horizontally. The housing 51 includes a motor housing 60 having a motor chamber 61 that houses a motor 100, a rear head 70 having an intermediate pressure chamber 71 that houses a two-stage compression mechanism 110, and a partition block 80 sandwiched between the motor housing 60 and the rear head 70. The motor housing 60, the rear head 70, and the partition block 80 are formed by castings of a metal material such as aluminum (including aluminum alloys).

[0032] The motor housing 60 is a cylindrical member with a bottom. One axial end of the motor housing 60 is closed by a bottom wall 62. The bottom wall 62 is formed integrally with the motor housing 60, for example. The other axial end of the motor housing 60 is completely open. The open end face 63 of the motor housing 60 is sometimes referred to as a first end face 63. The first end face 63 is a flat face perpendicular to the axial center line CL1 of the motor housing 60. A motor chamber 61 is formed inside the motor housing 60. An inverter housing 65 is attached to an outer wall surface 62a of the bottom wall 62 of the motor housing 60. An inverter device 66 for supplying driving power to the motor 100 is housed in the inverter housing 65.

[0033] Furthermore, the motor housing 60 has a suction port 68 that draws refrigerant from the outside into the motor chamber 61. More specifically, a boss portion 69 that protrudes radially outward is provided on the outer circumferential surface 60a of the motor housing 60. The suction port 68 opens into this boss portion 69. The third flow path 24 (refrigerant supply pipe 24) shown in FIG. 1 is connected to this suction port 68.

[0034] The rear head 70 (compressor housing 70) is a cylindrical member with a bottom. One axial end of the rear head 70 is closed by a bottom wall 72. This bottom wall 72 is formed integrally with the rear head 70, for example. The other axial end of the rear head 70 is completely open. The open end face 73 of the rear head 70 is sometimes referred to as the second end face 73. This second end face 73 is a flat surface perpendicular to the axial center line CL1 of the motor housing 60 and faces the first end face 63 of the motor housing 60. The interior of the rear head 70 is formed as an intermediate pressure chamber 71.

[0035] Furthermore, the rear head 70 has an oil separation chamber 74 that separates oil from the refrigerant compressed by the two-stage compression mechanism 110, and a discharge port 75 that discharges to the outside the gaseous refrigerant from which the oil has been separated by this oil separation chamber 74. The discharge port 75 is connected to the fourth flow path 25 (refrigerant discharge pipe 25) shown in FIG.

[0036] The partition block 80 is a disk-shaped member that separates the motor chamber 61 and the intermediate pressure chamber 71, and is sandwiched between the first end face 63 of the motor housing 60 and the second end face 73 of the rear head 70. More specifically, as shown in FIG. 3, the partition block 80 has a first mating surface 81 that faces the first end face 63 of the motor housing 60 and the motor chamber 61, and a second mating surface 82 that faces the second end face 73 of the rear head 70 and the intermediate pressure chamber 71. The first mating surface 81 and the second mating surface 82 are flat surfaces that are perpendicular to the center line CL1 of the motor housing 60 in the axial direction. The first mating surface 81 and the second mating surface 82 may be appropriately referred to as the "first flat surface 81 and the second flat surface 82."

[0037] The gap between the first end face 63 of the motor housing 60 and the first mating surface 81 of the partition block 80, and the gap between the second end face 73 of the rear head 70 and the second mating surface 82 of the partition block 80 are sealed by sealing members (not shown) such as gaskets or O-rings. Both the relative rotation and the relative axial movement of the partition block 80 with respect to the motor housing 60 and the rear head 70 are restricted. For example, the partition block 80 is fixed integrally with the motor housing 60 and the rear head 70 by fastening members 91 such as bolts.

[0038] Next, the motor 100 will be described. As shown in FIG. 2, the motor 100 includes an output shaft 101 (motor shaft 101), a rotor 102 fixed to the output shaft 101, and a cylindrical stator 103 surrounding the periphery of the rotor 102.

[0039] The output shaft 101 has a rotation center on a center line CL1 in the axial direction of the motor housing 60, extends from the motor chamber 61 toward the intermediate pressure chamber 71, penetrates the partition block 80, and is drivably connected to the two-stage compression mechanism 110. That is, the output shaft 101 of the motor 100 also serves as the rotating shaft 101 of the two-stage compression mechanism 110. Hereinafter, the output shaft 101 of the motor 100 may be appropriately referred to as the "rotating shaft 101 of the two-stage compression mechanism 110". This output shaft 101 (rotating shaft 101) is rotatably supported by a first bearing 104 provided in the partition block 80 and a second bearing 105 provided in the bottom wall 62 of the motor housing 60.

[0040] 3, a shaft support portion 83 for mounting the first bearing 104 is formed integrally with the partition block 80. That is, the partition block 80 is integrally provided with the shaft support portion 83 for supporting the rotating shaft 101 of the two-stage compression mechanism 110. This shaft support portion 83 protrudes from the first mating surface 81 of the partition block 80 toward the motor chamber 61. The shaft support portion 83 includes a configuration for directly supporting the rotating shaft 101 without the first bearing 104 being interposed therebetween.

[0041] The center line CL1 in the axial direction of the motor housing 60 may be referred to as "the center line CL1 of the output shaft 101 (rotating shaft 101)." The output shaft 101 of the motor 100 may be configured as a separate member from the output shaft of the two-stage compression mechanism 110. In that case, the output shaft 101 of the motor 100 is configured with a connecting member such as a coupling to the output shaft of the two-stage compression mechanism 110.

[0042] The rotor 102 is rotatable about a center line CL1 of the output shaft 101 (rotating shaft 101). The stator 103 is disposed radially outward of the rotor 102 and fixed to an inner circumferential surface 60b of the motor housing 60.

[0043] Next, the two-stage compression mechanism 110 will be described. As shown in Fig. 3, the low-stage compressor 120 and the high-stage compressor 130 constituting the two-stage compression mechanism 110 are both configured as so-called rolling piston type rotary compressors that compress using rotating bodies 122, 132 (pistons 132, 132) and cylinders 124, 134 that rotate. The low-stage compressor 120 and the high-stage compressor 130 have substantially the same configuration and are arranged on the center line CL1 of the rotating shaft 101 (output shaft 101). The low-stage compressor 120 is located on the partition block 80 side of the intermediate pressure chamber 71. The high-stage compressor 130 is located on the bottom wall 72 side of the rear head 70 of the intermediate pressure chamber 71.

[0044] 3 and 4, the low-stage compressor 120 includes a first eccentric shaft 121 that is integral with the rotating shaft 101, an annular first piston 122 (first rotor 122) that fits onto the first eccentric shaft 121, and a flat first cylinder 124 that has a first cylinder chamber 123 that allows the rotational motion of the first piston 122. A center line CL2 of the first eccentric shaft 121 is offset from a center line CL1 of the rotating shaft 101.

[0045] The first cylinder 124 is restricted from rotating relative to the rear head 70. The first cylinder 124 has a first surface 124a facing the second mating surface 82 of the partition block 80, and a second surface 124b facing the second cylinder 134 of the high-stage side compressor 130. The first surface 124a and the second surface 124b of the first cylinder 124 are flat surfaces perpendicular to the center line CL1 of the motor housing 60 in the axial direction.

[0046] The first cylinder chamber 123 is a circular hole concentric with the center line CL1 of the rotary shaft 101, and passes through the first cylinder 124. The first cylinder 124 further has a first suction passage 125 and a first discharge passage 126 which communicate with the first cylinder chamber 123. The first suction passage 125 and the first discharge passage 126 open to a first surface 124a of the first cylinder 124.

[0047] The outer diameter of the first piston 122 is smaller than the inner diameter of the first cylinder chamber 123. A vertical plate-shaped first vane 127 is in contact with the outer circumferential surface of the first piston 122 so as to be movable forward and backward. The first vane 127 divides the first cylinder chamber 123 into a suction chamber and a compression chamber. The tip of the first vane 127 is pressed against the outer circumferential surface of the first piston 122 by a first spring 128. The first piston 122 revolves within the first cylinder chamber 123. The refrigerant introduced into the first cylinder chamber 123 from the first suction passage 125 is compressed by the revolution of the first piston 122 and is discharged from the first discharge passage 126.

[0048] 3 and 5, like the low-stage compressor 120, the high-stage compressor 130 includes a second eccentric shaft 131 integrally provided with the rotating shaft 101, an annular second piston 132 (second rotating body 132) fitted with the second eccentric shaft 131, and a flat second cylinder 134 having a second cylinder chamber 133 that allows the rotational motion of the second piston 132. A center line CL3 of the second eccentric shaft 131 is offset from a center line CL1 of the rotating shaft 101.

[0049] The second cylinder 134 is restricted from rotating relative to the rear head 70. Furthermore, the second cylinder 134 has a first surface 134a facing the second surface 124b of the first cylinder 124 and a second surface 134b facing the bottom wall 72 of the rear head 70. The first surface 134a and the second surface 134b of the second cylinder 134 are flat surfaces perpendicular to the center line CL1 of the motor housing 60 in the axial direction.

[0050] The second cylinder chamber 133 is a circular hole concentric with the center line CL1 of the rotary shaft 101, and passes through the second cylinder 134. The second cylinder 134 further has a second suction passage 135 and a second discharge passage 136 which communicate with the second cylinder chamber 133. The second suction passage 135 opens to the outer circumferential surface of the second cylinder 134, thereby communicating the second cylinder chamber 133 with the intermediate pressure chamber 71. The second discharge passage 136 opens to a second surface 134b of the second cylinder 134.

[0051] The outer diameter of the second piston 132 is smaller than the inner diameter of the second cylinder chamber 133. A vertical plate-shaped second vane 137 is in contact with the outer circumferential surface of the second piston 132 so as to be movable forward and backward. The second vane 137 divides the second cylinder chamber 133 into a suction chamber and a compression chamber. The tip of the second vane 137 is pressed against the outer circumferential surface of the second piston 132 by a second spring 138. The second piston 132 revolves within the second cylinder chamber 133. The refrigerant introduced from the second suction passage 135 into the second cylinder chamber 133 is compressed by the revolution of the second piston 132 and is discharged from the second discharge passage 136.

[0052] The center line CL2 of the first eccentric shaft 121 and the center line CL3 of the second eccentric shaft 131 are provided at positions symmetrical with respect to the center line CL1 of the rotation shaft 101.

[0053] 3, the first cylinder chamber 123 is closed on the partition block 80 side by a flat first closing plate 141. This first closing plate 141 is sandwiched between the second mating surface 82 of the partition block 80 and the first surface 124a of the first cylinder 124.

[0054] Furthermore, the first closure plate 141 has a first through hole 141a communicating with the suction port 125a of the first suction passage 125 and a second through hole 141b communicating with the first discharge passage 126. The first through hole 141a and the second through hole 141b penetrate the first closure plate 141 in the plate thickness direction.

[0055] The suction port 125a of the first suction passage 125 communicates with the suction passage 84 of the partition block 80 through the first through hole 141a of the first closing plate 141. This suction passage 84 penetrates the partition block 80 in the axial direction of the motor housing 60. In other words, the suction passage 84 is located inside the partition block 80. Therefore, the first cylinder chamber 123 communicates with the suction port 68 of the motor housing 60 (see FIG. 2) through the path of the first suction passage 125, the first through hole 141a of the first closing plate 141, the suction passage 84 of the partition block 80, and the motor chamber 61.

[0056] The partition block 80 has a communication groove 85 that communicates the second through hole 141b of the first closing plate 141 and the intermediate pressure chamber 71. This communication groove 85 is formed in the second mating surface 82 of the partition block 80. A discharge valve 86 that opens and closes the opening of the second through hole 141b is provided in the communication groove 85. This discharge valve 86 is a check valve, for example a reed valve, that allows the injection gas refrigerant to flow only from the first discharge passage 126 to the communication groove 85. The first cylinder chamber 123 communicates with the second cylinder chamber 133 via the first discharge passage 126, the second through hole 141b, the communication groove 85, the intermediate pressure chamber 71, and the second suction passage 135.

[0057] The space between the first cylinder chamber 123 and the second cylinder chamber 133 is closed by a flat second closing plate 142. The second closing plate 142 is sandwiched between the second surface 124b of the first cylinder 124 and the first surface 134a of the second cylinder 134.

[0058] The second cylinder chamber 133 is closed on the bottom wall 72 side of the rear head 70 by a flat third closing plate 143. This third closing plate 143 covers the entire second surface 134b of the second cylinder 134. Furthermore, the third closing plate 143 is restricted from moving toward the bottom wall 72 side of the rear head 70 by a stepped surface 76 inside the rear head 70.

[0059] The first cylinder 124, the second cylinder 134, the first closing plate 141, the second closing plate 142 and the third closing plate 143 are sandwiched in the axial direction of the rear head 70 by the step surface 76 of the rear head 70 and the partition block 80.

[0060] Inside the rear head 70, a discharge chamber 144 is formed, which is partitioned by the bottom wall 72 and a third closing plate 143. The third closing plate 143 has a communication hole 143a that communicates the second discharge passage 136 of the second cylinder 134 and the discharge chamber 144. A discharge valve 145 that opens and closes the opening of the through hole 143a is provided in the discharge chamber 144. The discharge valve 145 is a check valve, such as a reed valve, that allows the injection gas refrigerant to flow only from the second discharge passage 136 to the discharge chamber 144. The discharge chamber 144 communicates with the oil separation chamber 74. The refrigerant in the high-stage compressor 130 can flow into the oil separation chamber 74 through the second discharge passage 136, the communication hole 143a, and the discharge chamber 144. It is preferable that the tip of the rotating shaft 101 is rotatably supported by a third bearing 146 provided in the third closing plate 143.

[0061] 6, the partition block 80 has an injection inlet 151, an injection outlet 152, and an injection passage 153. The injection passage 153 communicates between the injection inlet 151 and the injection outlet 152. At least the injection outlet 152 and the injection passage 153 are disposed within the partition block 80.

[0062] The injection inlet 151 is formed integrally with, for example, the partition block 80. More specifically, a boss portion 154 that protrudes radially outward is provided on the outer circumferential surface 87 of the partition block 80. The injection inlet 151 opens at this boss portion 154. The injection inlet 151 is capable of introducing an injection gas refrigerant by connecting an injection pipe 22 (see FIG. 1).

[0063] The injection outlet 152 is in communication with the intermediate pressure chamber 71 by opening to a second mating surface 82 (second flat surface 82) of the partition block 80 that faces the intermediate pressure chamber 71. Therefore, the injection outlet 152 can lead out the injection gas refrigerant to the intermediate pressure chamber 71.

[0064] A check valve 160 is provided at the injection outlet 152. This check valve 160 allows the injection gas refrigerant to flow only from the injection passage 153 to the intermediate pressure chamber 71. In other words, when the pressure in the injection passage 153 increases to exceed the pressure in the intermediate pressure chamber 71, the check valve 160 opens due to the pressure difference.

[0065] The check valve 160 is provided on the flat second mating surface 82 of the partition block 80 that faces the intermediate pressure chamber 71. The check valve 160 is configured by, for example, a reed valve 161. The reed valve 161 has one end of a thin elastic plate fixed and opens only in one direction, that is, only in the direction that allows the flow of injection gas refrigerant from the injection passage 153 to the intermediate pressure chamber 71.

[0066] Next, the flow of the refrigerant in the electric compressor 50 will be described. As shown in Fig. 2, the refrigerant sucked from the suction port 68 of the motor housing 60 passes through a gap in the motor 100 disposed in the motor chamber 61, thereby cooling the motor 100, and then flows into the suction passage 84 of the partition block 80. The refrigerant that has passed through the suction passage 84 passes through the first through hole 141a of the first closing plate 141 and the first suction passage 125 of the low-stage compressor 120, and enters the first cylinder chamber 123.

[0067] 3, the refrigerant compressed by the low-stage compressor 120 flows from the first cylinder chamber 123 through the first discharge passage 126, the second through hole 141b of the first closing plate 141, the communication groove 85 of the partition block 80, the intermediate pressure chamber 71, and the second suction passage 135 to the second cylinder chamber 133. The refrigerant further compressed by the high-stage compressor 130 flows from the second cylinder chamber 133 through the second discharge passage 136, the communication hole 143a of the third closing plate 143, the discharge chamber 144, and the oil separation chamber 74 to the discharge port 75 of the rear head 70.

[0068] The above explanation can be summarized as follows.

[0069] As shown in FIG. 2, the electric compressor 50 includes a two-stage compression mechanism 110 having a low-stage side compressor 120 and a high-stage side compressor 130, a motor 100 that drives the two-stage compression mechanism 110, a motor housing 60 that has a motor chamber 61 that houses the motor 100, a rear head 70 that has an intermediate pressure chamber 71 that houses the two-stage compression mechanism 110, and a partition block 80 that is sandwiched between the rear head 70 and the motor housing 60 and separates the motor chamber 61 from the intermediate pressure chamber 71.

[0070] As shown in FIG. 6, the partition block 80 has an injection inlet 151 through which an injection gas refrigerant can be introduced, an injection outlet 152 through which the injection gas refrigerant can be discharged to the intermediate pressure chamber 71, and an injection passage 153 that connects the injection inlet 151 and the injection outlet 152. In this way, the partition block 80 is extremely sturdy since it is sandwiched between the motor housing 60 and the rear head 70. The sturdy partition block 80 is provided with an injection inlet 151, an injection outlet 152, and an injection passage 153. This enables the injection pipe 22 to be supported firmly by the electric compressor 50.

[0071] 6, a check valve 160 is disposed at the injection outlet 152 to allow the injection gas refrigerant to flow only from the injection passage 153 to the intermediate pressure chamber 71. This makes it possible to prevent the refrigerant from flowing back from the intermediate pressure chamber 71 to the injection inlet 151. As a result, the efficiency of the injection type refrigeration cycle 10, 30 (see FIGS. 1A and 1B) can be improved.

[0072] 6, the injection outlet 152 and the check valve 160 are provided on a flat surface 82 (second flat surface 82, second mating surface 82) of the partition block 80 that faces the intermediate pressure chamber 71. By providing the check valve 160 on the flat surface 82 of the partition block 80 in this manner, the configuration and mounting structure of the check valve 160 can be simplified.

[0073] 6, the check valve 160 is composed of a reed valve 161. The check valve 160 has a configuration in which the reed valve 161 is assembled to the flat surface 82 (second flat surface 82, second mating surface 82) of the partition block 80 that faces the intermediate pressure chamber 71, and therefore can have a simple structure. As shown in FIG. 3, the partition block 80 has a suction passage 84 therein, which connects the motor chamber 61 with the suction port 125a of the low-stage compressor 120.

[0074] In this manner, the partition block 80 is provided therein with the suction passage 84 that connects the motor chamber 61 with the suction port 125a of the low-stage compressor 120, the injection inlet 151, the injection outlet 152, and the injection passage 153. In other words, the suction passage 84, the injection inlet 151, the injection outlet 152, and the injection passage 153 can all be concentrated in only the partition block 80, and the configuration of the electric compressor 50 can be simplified.

[0075] As shown in FIG. 3, the partition block 80 is integrally provided with a shaft support portion 83 that supports the rotating shaft 101 of the two-stage compression mechanism 110. Therefore, the partition block 80 that separates the motor chamber 61 and the intermediate pressure chamber 71 can be utilized to support the rotating shaft 101 of the two-stage compression mechanism 110. There is no need to provide a separate member for supporting the rotating shaft 101. The configuration of the electric compressor 50 can be simplified. In addition, since the rotating shaft 101 is supported by the partition block 80 sandwiched between the motor housing 60 and the rear head 70, the entire electric compressor 50 becomes robust. The shaft support portion 83 can support the rotating shaft 101 via a bearing 104 or a plain bearing, or directly.

[0076] As long as the functions and effects of the present invention are achieved, the present invention is not limited to the examples. For example, the electric compressor 50 is not limited to a horizontal type electric compressor, but may be a vertical type electric compressor. [Industrial Applicability]

[0077] The electric compressor 50 of the present invention is suitable for use in the injection type refrigeration cycles 10 and 30. [Explanation of symbols]

[0078] 10,30 Injection type refrigeration cycle 50 Electric Compressor 60 Motor housing 61 Motor Room 68 Intake port 70 Rear head (compressor housing) 71 Intermediate pressure chamber 75 Discharge port 80 Partition Block 82 Flat surface (second mating surface, second flat surface) 83 Shaft support part 84 Suction passage 85 Communication groove 100 Motor 101 Rotating shaft (output shaft) 110 Two-stage compression mechanism 120 Low stage compressor 125 1st suction passage 125a Inlet 130 High stage compressor 135 2nd suction passage 136 2nd discharge passage 151 Injection inlet 152 Injection outlet 153 Injection Passage 160 Check valve 161 Reed valve

Claims

1. A two-stage compression mechanism (110) having a low-stage compressor (120) and a high-stage compressor (130); A motor (100) that drives the two-stage compression mechanism (110); a motor housing (60) having a motor chamber (61) for accommodating the motor (100); a rear head (70) having an intermediate pressure chamber (71) for accommodating the two-stage compression mechanism (110); a partition block (80) that is sandwiched between the rear head (70) and the motor housing (60) and separates the motor chamber (61) from the intermediate pressure chamber (71); In an electric compressor (50), The partition block (80) is an injection inlet (151) through which an injection gas refrigerant can be introduced; an injection outlet (152) capable of leading the injection gas refrigerant to the intermediate pressure chamber (71); and an injection passage (153) communicating between the injection inlet (151) and the injection outlet (152).

2. 2. The electric compressor according to claim 1, wherein a check valve (160) is disposed in the injection outlet (152) to allow the injection gas refrigerant to flow only from the injection passage (153) to the intermediate pressure chamber (71).

3. 3. The electric compressor according to claim 2, wherein the injection outlet (152) and the check valve (160) are provided on a flat surface (82) of the partition block (80) that faces the intermediate pressure chamber (71).

4. 4. The electric compressor according to claim 3, wherein the check valve (160) is a reed valve (161).

5. 5. The electric compressor according to claim 1, wherein the partition block (80) has a suction passage (84) inside the partition block (80) that connects the motor chamber (61) and a suction port (125a) of the low-stage side compressor (120).

6. 2. The electric compressor according to claim 1, wherein the partition block (80) is integrally provided with a shaft support portion (83) that supports a rotating shaft (101) of the two-stage compression mechanism (110).

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