Electric compressor

Abstract

[Problem] To strengthen support for an injection pipe by an electric compressor. [Solution] An electric compressor (50) comprises: a motor housing (60) including a motor chamber (61) that houses a motor (100); a rear head (70) including an intermediate pressure chamber (71) that houses a two-stage compression mechanism (110); and a partition block (80) that is held 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 can be introduced; an injection outlet (152) through which the injection gas refrigerant can be introduced to the intermediate pressure chamber (71); and an injection passage (153) that provides communication between the injection inlet (151) and the injection outlet (152).

Description

Electric compressor

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

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

[0003] According to the technology known from Patent Document 1, a so-called vertically mounted electric compressor is configured in which a low-stage compressor is disposed below a motor inside a housing, and a high-stage compressor is disposed below the low-stage compressor. The interior 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 connected to the second sealed chamber. Therefore, the second sealed chamber is configured to have an intermediate-pressure atmosphere. The suction passage of the low-stage compression mechanism is connected to 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 is connected to the second sealed chamber. The discharge passage of the high-stage compression mechanism is connected to the discharge pipe for the high-pressure refrigerant.

[0005] Japanese Patent Application Laid-Open No. 2000-054975

[0006] However, automotive air conditioners are subject to high refrigerant pressures due to vehicle vibrations and high temperatures in the hot sun, so extremely strict reliability is required. 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 will not 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 the injection pipe by the electric compressor.

[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 forms.

[0009] According to the present invention, there is provided 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) that connects the injection inlet (151) and the injection outlet (152).

[0010] Preferably, a check valve (160) is arranged 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).

[0011] More preferably, 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).

[0012] Preferably, the check valve (160) is constituted by a reed valve (161).

[0013] More preferably, the partition block (80) has an intake passage (84) therein that connects the motor chamber (61) with the intake 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 rotary shaft (101) of the two-stage compression mechanism (110).

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

[0016] 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. It is a cross-sectional view of the electric compressor shown in Fig. 1. It is an enlarged view of the periphery of a two-stage compression mechanism shown in Fig. 2. It is a cross-sectional view of the low-stage side compressor shown in Fig. 3 as seen from the axial direction of a motor shaft. It is a cross-sectional view of the periphery of the high-stage side compressor shown in Fig. 3 as seen from the axial direction of a motor shaft. It is a cross-sectional view of the periphery of an injection inlet in the partition block shown in Fig. 3.

[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] 1 to 6, an electric compressor 50 according to an embodiment and injection-type refrigeration cycles 10 and 30 including the electric compressor 50 will be described.

[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 automotive air conditioning system, and performs cooling and heating using an interior air conditioning unit (not shown). Note that the use of this refrigeration cycle 10 is not limited. Furthermore, this refrigeration cycle 10 is suitable for use with R744 refrigerant, but other refrigerants (e.g., R134a refrigerant and R1234yf refrigerant) can also 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) obtained by gas-liquid separation 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 compressor 120 and a high-stage compressor 130. The electric compressor 50 also includes an intake port 68 that can draw in a refrigerant from the outside (evaporator 11), a discharge port 75 that can discharge the refrigerant to the outside (gas cooler 12), and an injection inlet 151 that can introduce an injection gas refrigerant.

[0023] A refrigerant outlet of the gas cooler 12 is connected to a refrigerant inlet of the gas-liquid separator 15 via a first flow path 21 and a first expansion valve 13. A refrigerant outlet of the gas-liquid separator 15 is connected to an injection pipe 22 through which injected gas refrigerant flows and a second flow path 23 through which 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 outside air by the gas cooler 12 flows to the suction port 68 of the electric compressor 50 via the first flow path 21, the first expansion valve 13, the gas-liquid separator 15, the second expansion valve 14, and the evaporator 11, and is compressed to a high pressure. The refrigerant compressed to a high pressure by the electric compressor 50 flows to the gas cooler 12 via the fourth flow path 25.

[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 through only the first expansion valve 13 of the two expansion valves 13, 14, passes through the gas-liquid separator 15 and flows through the injection pipe 22 to the injection inlet 151 of the electric compressor 50. 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"). The refrigeration cycle 30 of this example includes an internal heat exchanger 31 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 via a first flow path 21. A portion 21a of the first flow path 21 between the gas cooler 12 and the internal heat exchanger 31, i.e., a branch point 21a, is branched by a branch path 41 and connected to the 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 via 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. As shown in Fig. 2, the electric compressor 50 has a so-called horizontally mounted electric compressor configuration in which a two-stage compression mechanism 110 is disposed next to a motor 100. The 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 installable horizontally. The housing 51 includes a motor housing 60 having a motor chamber 61 that houses the motor 100, a rear head 70 having an intermediate pressure chamber 71 that houses the 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 an aluminum alloy).

[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. This bottom wall 62 is, for example, formed integrally with the motor housing 60. 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 the first end face 63. This first end face 63 is a flat surface 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 the outer wall surface 62a of the bottom wall 62 of the motor housing 60. The inverter housing 65 houses an inverter device 66 for supplying drive power to the motor 100.

[0033] The motor housing 60 also has a suction port 68 through which refrigerant is drawn from the outside into the motor chamber 61. More specifically, a boss 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 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. An intermediate pressure chamber 71 is formed inside the rear head 70.

[0035] Furthermore, rear head 70 has an oil separation chamber 74 that separates oil from the refrigerant compressed by 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. This discharge port 75 is connected to 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 axial center line CL1 of the motor housing 60. The first mating surface 81 and the second mating surface 82 may be referred to as the "first flat surface 81 and the second flat surface 82" as appropriate.

[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. The partition block 80 is restricted in both relative rotation and axial movement with respect to the motor housing 60 and the rear head 70. 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, a description will be given of the motor 100. 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 rotor 102.

[0039] The output shaft 101 has a rotation center on the axial center line CL1 of the motor housing 60, extends from the motor chamber 61 toward the intermediate pressure chamber 71, penetrates the partition block 80, and is drivingly connected to the two-stage compression mechanism 110. In other words, 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. In other words, the partition block 80 is integrally provided with the shaft support portion 83 that supports 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. Note that the shaft support portion 83 includes a configuration that directly supports the rotating shaft 101 without using the first bearing 104.

[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 connected to the output shaft of the two-stage compression mechanism 110 by a connecting member such as a coupling.

[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 is fixed to an inner peripheral 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 each have a so-called rolling piston type rotary compressor configuration, compressing air 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 rotary 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 rotary shaft 101, an annular first piston 122 (first rotor 122) that is fitted onto the first eccentric shaft 121, and a flat first cylinder 124 that has a first cylinder chamber 123 that allows rotational movement of the first piston 122. A center line CL2 of the first eccentric shaft 121 is offset from a center line CL1 of the rotary 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 compressor 130. The first surface 124a and the second surface 124b of the first cylinder 124 are flat surfaces that are perpendicular to the axial center line CL1 of the motor housing 60.

[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 peripheral surface of the first piston 122 and is movable back and forth. 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 peripheral surface of the first piston 122 by a first spring 128. The first piston 122 revolves within the first cylinder chamber 123. Refrigerant introduced from the first suction passage 125 into the first cylinder chamber 123 is compressed by the orbital motion of the first piston 122 and is discharged from a first discharge passage 126.

[0048] 3 and 5 , similar to the low-stage compressor 120, the high-stage compressor 130 includes a second eccentric shaft 131 provided integrally with the rotating shaft 101, an annular second piston 132 (second rotating body 132) fitted onto the second eccentric shaft 131, and a flat second cylinder 134 having a second cylinder chamber 133 that allows rotational movement 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. The second cylinder 134 further 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 that are perpendicular to the axial center line CL1 of the motor housing 60.

[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 that communicate with the second cylinder chamber 133. The second suction passage 135 opens to the outer peripheral 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 peripheral surface of the second piston 132 and is movable back and forth. 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 peripheral surface of the second piston 132 by a second spring 138. The second piston 132 revolves within the second cylinder chamber 133. Refrigerant introduced from the second suction passage 135 into the second cylinder chamber 133 is compressed by the orbital motion 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 closing 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 closing 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) via 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 connects the second through-hole 141b of the first closing plate 141 with 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, such as a reed valve, that allows injection gas refrigerant to flow only from the first discharge passage 126 to the communication groove 85. The first cylinder chamber 123 is in communication 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. This 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 side facing the bottom wall 72 of the rear head 70 by a flat third closing plate 143. This third closing plate 143 entirely covers the second surface 134b of the second cylinder 134. Furthermore, the step surface 76 inside the rear head 70 restricts the third closing plate 143 from moving toward the bottom wall 72 of 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] A discharge chamber 144 is defined within the rear head 70 by the bottom wall 72 and a third closure plate 143. The third closure plate 143 has a communication hole 143a that connects the second discharge passage 136 of the second cylinder 134 to the discharge chamber 144. A discharge valve 145 that opens and closes the through-hole 143a is provided within the discharge chamber 144. The discharge valve 145 is a check valve, such as a reed valve, that allows injection gas refrigerant to flow only from the second discharge passage 136 to the discharge chamber 144. The discharge chamber 144 is connected to the oil separation chamber 74. 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. Preferably, the tip of the rotating shaft 101 is rotatably supported by a third bearing 146 provided in the third closure 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 peripheral surface 87 of the partition block 80. The injection inlet 151 opens at this boss portion 154. The injection inlet 151 is connected to the injection pipe 22 (see FIG. 1 ) to allow the introduction of an injection gas refrigerant.

[0063] The injection outlet 152 is connected to 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 injected 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, which 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 injection gas refrigerant to flow from the injection passage 153 to the intermediate pressure chamber 71.

[0066] Next, the flow of refrigerant within the electric compressor 50 will be described. As shown in Figure 2, the refrigerant drawn into the suction port 68 of the motor housing 60 passes through the gaps in the motor 100 disposed in the motor chamber 61, 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 closure plate 141 and the first suction passage 125 of the low-stage compressor 120, and enters the first cylinder chamber 123.

[0067] 3, 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 closure plate 141, the communicating groove 85 of the partition block 80, the intermediate pressure chamber 71, and the second suction passage 135 to the second cylinder chamber 133. Refrigerant further compressed by the high-stage compressor 130 flows from the second cylinder chamber 133 through the second discharge passage 136, the communicating hole 143a of the third closure 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] 6, the partition block 80 has an injection inlet 151 through which the 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. As described above, the partition block 80 is sandwiched between the motor housing 60 and the rear head 70, and is therefore extremely sturdy. The injection inlet 151, the injection outlet 152, and the injection passage 153 are provided in this sturdy partition block 80. This allows the electric compressor 50 to firmly support the injection pipe 22.

[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 prevents 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 cycles 10 and 30 (see FIGS. 1A and 1B) can be improved.

[0072] 6, the injection outlet 152 and the check valve 160 are provided on the 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 way, the configuration and installation structure of the check valve 160 can be simplified.

[0073] As shown in Fig. 6, the check valve 160 is constituted by a reed valve 161. The check valve 160 can have a simple structure because the reed valve 161 is attached 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. As shown in Fig. 3, the partition block 80 has an intake passage 84 therein that connects the motor chamber 61 and the intake port 125a of the low-stage compressor 120.

[0074] As described above, the partition block 80 is provided with the suction passage 84, which 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 integrated into the partition block 80 alone, thereby simplifying the configuration of the electric compressor 50.

[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, which separates the motor chamber 61 and the intermediate pressure chamber 71, can be used 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. This simplifies the configuration of the electric compressor 50. 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 is made robust. The shaft support portion 83 can support the rotating shaft 101 directly or via a bearing 104 or a plain bearing.

[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 horizontally-mounted electric compressor, but may be a vertically-mounted electric compressor.

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

[0078] 10, 30 Injection type refrigeration cycle 50 Electric compressor 60 Motor housing 61 Motor chamber 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 portion 84 Intake passage 85 Communicating groove 100 Motor 101 Rotating shaft (output shaft) 110 Two-stage compression mechanism 120 Low-stage side compressor 125 First intake passage 125a Intake port 130 High-stage side compressor 135 Second intake passage 136 Second discharge passage 151 Injection inlet 152 Injection outlet 153 Injection passage 160 Check valve 161 Reed valve

Claims

1. 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) provided with a motor chamber (61) that houses the motor (100), a rear head (70) provided with 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) and the intermediate pressure chamber (71), wherein the partition block (80) has an injection inlet (151) through which an injection gas refrigerant can be introduced, and an injection outlet (152) through which the injection gas refrigerant can be led out to the intermediate pressure chamber (71), and an injection passage (153) communicating between the injection inlet (151) and the injection outlet (152).

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

5. An electric compressor as described in any one of claims 1 to 4, wherein the partition block (80) has an intake passage (84) inside the partition block (80) that connects the motor chamber (61) and the intake port (125a) of the low-stage compressor (120).

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

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