Electrical compressor

Abstract

[Problem] To enable stable supporting of a drive shaft by a bearing fixed to a partition block and ensuring performance and durability of a compression mechanism. [Solution] An electrical compressor (50) comprises: a motor housing (60) having a motor chamber (61); a rear head (70) having an intermediate chamber (71); a partition block (80) that partitions the motor chamber (61) and the intermediate chamber (71); and a bearing (106) fixed to the partition block (80). The intermediate chamber (71) houses a compression mechanism (110). The bearing (106) supports a drive shaft (105) for driving the compression mechanism (110). The partition block (80) has a shaft through-hole (83) through which the drive shaft (105) can penetrate. A closing plate (141) composed of a member different from the partition block (80) is interposed between the partition block (80) and the compression mechanism (110).

Description

Electric compressor

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

[0002] Among electric compressors, there is a rolling piston type rotary compressor equipped with a compression mechanism having multiple compressors. Such compression mechanisms include a multi-stage compression mechanism in which multiple compressors are arranged in series for compression, and a parallel compression mechanism (e.g., a twin compression mechanism) in which multiple compressors are arranged in parallel for compression. For example, the technology disclosed in Patent Document 1 is known as an electric compressor equipped with a multi-stage compression mechanism.

[0003] According to the technology known from Patent Document 1, a so-called vertically mounted electric compressor is configured such that a high-stage compression element is arranged below a motor inside a housing, and a low-stage compression element is arranged below this high-stage compression element.

[0004] This electric compressor is provided with a drive shaft that transmits power from a motor to the high-stage compression element and the low-stage compression element. The drive shaft is supported by an upper bearing member attached to the upper surface of the second cylinder block of the high-stage compression element and a lower bearing member attached to the lower surface of the first cylinder block of the low-stage compression element. Rolling piston type rotary compressors are generally structured so that the drive shaft is supported by a slide bearing.

[0005] Japanese Patent Application Publication No. 5-133368

[0006] Electric compressors are used, for example, in vehicle air conditioners. Electric compressors used in vehicle air conditioners are required to operate at high speeds, for example, to rapidly cool the hot interior of a vehicle in the summer and to maintain a constant battery temperature in an electric vehicle during rapid charging. Therefore, it has been considered to use rolling bearings, such as ball bearings, that can accommodate high-speed rotation in electric compressors for vehicle air conditioners.

[0007] However, the use of rolling bearings requires a press-fit fit between the bearing support member and the rolling bearings to fix them in place. In particular, the rolling bearing disposed between the motor and the high-stage compression element needs to be relatively larger than the other rolling bearings.

[0008] If this large rolling bearing were used in the electric compressor of Patent Document 1, the bearing would be press-fitted into the upper bearing member of the high-stage compression element. The upper bearing member faces the second cylinder and forms a piston sliding surface on which the piston slides. Therefore, if the upper bearing member is deformed by press-fitting, the piston sliding surface will also deform and will not remain flat. As a result, abnormal wear may occur on the piston sliding surface and the piston, resulting in performance degradation and reliability degradation. This issue is also present in electric compressors with parallel compression mechanisms.

[0009] The present invention has been made to solve the above-mentioned problems, and its objective is to provide a technology that can stably support the drive shaft using a bearing fixed to a partition block, while ensuring the performance and durability of the compression mechanism.

[0010] 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.

[0011] According to the present disclosure, first, a compressor includes a compression mechanism (110; 260), a drive shaft (105) that drives the compression mechanism (110; 260), a motor (100) that drives the drive shaft (105), a motor housing (60) having a motor chamber (61) that houses the motor (100), a rear head (70) having an intermediate chamber (71) that houses the compression mechanism (110; 260), and a compressor located between the rear head (70) and the motor housing (60) that connects the intermediate chamber (71) and the motor chamber (61). 1) and the drive shaft (105) and has a shaft through-hole (83) through which the drive shaft (105) can pass, and a bearing (106) fixed to the partition block (80) and rotatably supporting the drive shaft (105), wherein a closing plate (141) made of a separate member from the partition block (80) is interposed between the partition block (80) and the compression mechanism (110; 260).

[0012] Secondly, preferably, in the electric compressor according to the first aspect, the bearing (106) is located on the opposite side of the partition block (80) from the compression mechanism (110; 260).

[0013] Thirdly, preferably, in the electric compressor according to any one of the first and second aspects, the compression mechanism (110; 260) is a rolling piston type rotary compressor including a cylinder (124) forming a cylinder chamber (123) and a piston (122) performing eccentric rotational motion within the cylinder chamber (123), and the piston (122) is positioned so as to be able to slide relative to a sliding surface (141c) of the closing plate (141).

[0014] Fourth, preferably, in the electric compressor described in any one of the first to third aspects, the compression mechanism (110; 260) is a multiple compressor configuration including a first compressor (120) and a second compressor (130).

[0015] Fifth, preferably, in the electric compressor according to the fourth aspect, the first compressor (120) is located closer to the partition block (80) than the second compressor (130), and the compression chamber (123b) of the first compressor (120) is in communication with the discharge chamber (144) via at least a discharge hole (141a) in the closing plate (141), a discharge valve (88) that opens and closes the discharge hole (141a), a discharge recess (87) in the partition block (80), and the intermediate chamber (71).

[0016] Sixth, preferably, in the electric compressors described in any one of the first to fifth aspects, the partition block (80) has a shaft seal retaining hole (85) positioned concentrically with the shaft through hole (83), the shaft seal retaining hole (85) opens to the closing plate (141) side of the partition block (80) and retains a shaft seal (108) that seals between the shaft through hole (83) and the drive shaft (105), and movement of the shaft seal (108) toward the open end of the shaft seal retaining hole (85) is regulated by the closing plate (141).

[0017] Seventh, preferably, in the electric compressor according to the fourth aspect, the partition block (80) has a suction passage (86) penetrating a first surface (81) facing the motor chamber (61) and a second surface (82) facing the intermediate chamber (71), the first compressor (120) has a suction port (125a) capable of drawing in a refrigerant, and the suction port (125a) is directly connected to the suction passage (86) and thereby communicates with the motor chamber (61) via the suction passage (86).

[0018] In the present disclosure, the bearing fixed to the partition block can stably support the drive shaft and ensure the performance and durability of the compression mechanism.

[0019] FIG. 1A is a conceptual diagram showing an example of an injection type refrigeration cycle according to a first embodiment, and FIG. 1B is a conceptual diagram showing another example of the injection type refrigeration cycle according to the first embodiment. A cross-sectional view of an electric compressor having a two-stage compression mechanism shown in FIG. 1. An enlarged view of the two-stage compression mechanism and its periphery shown in FIG. 2. An enlarged cross-sectional view of the partition block and the first compressor and its periphery shown in FIG. 3. An exploded view of the partition block and the first compressor shown in FIG. 4. A cross-sectional view of the first compressor shown in FIG. 3 as seen from the axial direction of the motor shaft. A cross-sectional view of the second compressor shown in FIG. 3 as seen from the axial direction of the motor shaft. A cross-sectional view of the injection inlet and its periphery in the partition block shown in FIG. 3. A cross-sectional view of the twin compression mechanism and its periphery of an electric compressor according to a second embodiment.

[0020] 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.

[0021] First Embodiment An electric compressor 50 according to a first embodiment and injection-type refrigeration cycles 10 and 30 including the electric compressor 50 will be described with reference to FIGS. 1 to 8. FIG.

[0022] 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.

[0023] 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 refrigerant gas (gas-phase refrigerant) separated into gas and liquid to the electric compressor 50. This intermediate-pressure refrigerant gas returned to the electric compressor 50 is called injection refrigerant gas.

[0024] 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 .

[0025] The electric compressor 50 includes a two-stage compression mechanism 110. The two-stage compression mechanism 110 includes a first compressor 120 and a second compressor 130. The electric compressor 50 further includes an intake port 68 through which refrigerant can be drawn from the outside (evaporator 11), a discharge port 75 through which refrigerant can be discharged to the outside (gas cooler 12), and an injection inlet 151 through which injection refrigerant gas can be introduced.

[0026] 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 refrigerant gas flows and a second flow path 23 through which refrigerant liquid flows. The injection pipe 22 is connected to an injection inlet 151 of the electric compressor 50.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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, and the heated refrigerant gas is passed through the injection pipe 22 to the injection inlet 151 of the electric compressor 50.

[0033] Next, the overall configuration of the electric compressor 50 will be described. As shown in Figure 2, the electric compressor 50 has the configuration of a so-called horizontally mounted electric compressor, 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, a drive shaft 105 driven by the motor 100, and the two-stage compression mechanism 110 driven by the drive shaft 105.

[0034] 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 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 made by casting metal materials such as aluminum (including aluminum alloys).

[0035] 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.

[0036] 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.

[0037] 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 chamber 71 is formed inside the rear head 70.

[0038] 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.

[0039] The partition block 80 is a disk-shaped member located between the motor housing 60 and the rear head 70, and separates the motor chamber 61 from the intermediate chamber 71. In other words, the partition block 80 is sandwiched between the first end surface 63 of the motor housing 60 and the second end surface 73 of the rear head 70.

[0040] 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 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.

[0041] 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.

[0042] Next, the motor 100 will be described. As shown in Figure 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. The rotor 102 is rotatable together with the output shaft 101. The stator 103 is disposed radially outward of the rotor 102 and is fixed to the inner circumferential surface 60b of the motor housing 60.

[0043] The drive shaft 105 of the present invention includes both a configuration in which it is also the output shaft 101 of the motor 100 (see FIG. 2 ) and a configuration in which it is a separate member (not shown) from the output shaft 101 of the motor 100. When the drive shaft 105 is a separate member from the output shaft 101, the shafts 101 and 105 are connected to each other by a connecting member such as a coupling. Here, a configuration in which the output shaft 101 of the motor 100 also serves as the drive shaft 105 will be described.

[0044] The drive shaft 105 (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 chamber 71, penetrates the partition block 80, and is drivingly connected to the two-stage compression mechanism 110. In this way, the output shaft 101 can directly or indirectly drive the two-stage compression mechanism 110. The longitudinal center line CL1 of the housing 60 may be referred to as the "center line CL1 of the drive shaft 105 (output shaft 101)."

[0045] As shown in FIGS. 2 and 4 , the drive shaft 105 is rotatably supported by a first bearing 106 provided in the partition block 80 and a second bearing 107 provided in the bottom wall 62 of the motor housing 60. The first bearing 106 is located on the side of the partition block 80 opposite the compression mechanism 110 (the side of the first mating surface 81). The first bearing 106 and the second bearing 107 are configured by rolling bearings or plain bearings. More preferably, by using rolling bearings for the first bearing 106 and the second bearing 107, the drive shaft 105 can be rotatably supported more stably and the offset load of the drive shaft 105 that deforms (distorts) the partition block 80 can be reduced, thereby preventing deformation from being transmitted to a sliding surface 141 c (piston sliding portion 141 c) of a first closure plate 141, which will be described later.

[0046] 4 and 5 , the partition block 80 has a shaft through-hole 83 through which the drive shaft 105 can pass, a bearing fixing portion 84 that fixes the first bearing 106, and a shaft seal retaining hole 85 that holds the shaft seal 108. The shaft through-hole 83, the fitting hole 84a of the bearing fixing portion 84, and the shaft seal retaining hole 85 are positioned on the center line CL1 of the drive shaft 105.

[0047] The bearing fixing portion 84 protrudes further toward the motor chamber 61 than the first mating surface 81 of the partition block 80. An outer peripheral surface 106a of the first bearing 106 is fixed into the fitting hole 84a of the bearing fixing portion 84 by press-fitting (e.g., interference fit).

[0048] The shaft seal retaining hole 85 opens to the second mating surface 82 (the two-stage compression mechanism 110 side) of the partition block 80. The shaft seal 108 is a member that seals between the shaft through hole 83 and the drive shaft 105, and is configured by, for example, a lip seal. This shaft seal 108 prevents the refrigerant present in the intermediate chamber 71 from leaking through the shaft through hole 83 into the motor chamber 61.

[0049] Next, the compression mechanism 110 will be described. As shown in FIG. 3 , the compression mechanism 110 is a two-stage compression mechanism (a type of multi-stage compression mechanism) including a first compressor 120 and a second compressor 130. This compression mechanism 110 (two-stage compression mechanism 110) is configured to compress air by arranging two compressors 120, 130 in series. The first compressor 120 and the second compressor 130 constituting this two-stage compression mechanism 110 are configured as so-called rolling piston rotary compressors that compress air using rotating bodies 122, 132 (pistons 122, 132) that rotate and cylinders 124, 134. That is, the first compressor 120 and the second compressor 130 are configured to compress air by using rotating bodies 122, 132 (pistons 122, 132) that rotate and cylinders 124, 134. That is, the first compressor 120 and the second compressor 130 are configured to compress air by using rotating bodies 122, 132 (pistons 122, 132) that rotate and cylinders 124, 134 that rotate eccentrically within the cylinder chambers 123, 133.

[0050] The first compressor 120 and the second compressor 130 have substantially the same configuration and are arranged on the center line CL1 of the drive shaft 105. However, the thickness of the cylinder 134 of the second compressor 130 is smaller than the thickness of the cylinder 124 of the first compressor 120. The first compressor 120 is located on the partition block 80 side of the intermediate chamber 71. The second compressor 130 is located on the bottom wall 72 side of the rear head 70 of the intermediate chamber 71. In other words, the first compressor 120 is located closer to the partition block 80 than the second compressor 130.

[0051] 3 and 6, the first compressor 120 includes a first eccentric shaft 121 provided integrally with the drive shaft 105, an annular first piston 122 (first rotor 122) fitted onto the first eccentric shaft 121, and a flat first cylinder 124 forming a first cylinder chamber 123 that allows 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 drive shaft 105. As a result, the first piston 122 performs eccentric rotational motion within the first cylinder chamber 123.

[0052] The first cylinder chamber 123 is a circular hole concentric with the center line CL1 of the drive shaft 105 and passes through a first cylinder 124. Relative rotation of the first cylinder 124 with respect to the rear head 70 is restricted. 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 second compressor 130. The first surface 124a and the second surface 124b of the first cylinder 124 are flat surfaces perpendicular to the axial center line CL1 of the motor housing 60. The first cylinder 124 further has a first suction passage 125 and a first discharge passage 126 that communicate with the first cylinder chamber 123. Details of the first suction passage 125 will be described later.

[0053] 4, the first discharge passage 126 opens to the first surface 124a of the first cylinder 124. In other words, the first discharge passage 126 does not open to the outer peripheral surface of the first cylinder 124. For example, the first discharge passage 126 is preferably formed to the first surface 124a while running along the inner wall surface 123c of the first cylinder 124 that defines the first cylinder chamber 123.

[0054] As shown in Figures 3 and 6, 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 tip of this first vane 127 is pressed against the outer peripheral surface of the first piston 122 by a first spring 128. The first vane 127 divides the first cylinder chamber 123 into a first suction chamber 123a and a first compression chamber 123b. The first suction chamber 123a is in communication with a first suction passage 125. The first compression chamber 123b is in communication with a first discharge passage 126. The first piston 122 revolves within the first cylinder chamber 123. The refrigerant introduced into the first suction chamber 123a (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 compression chamber 123b through the first discharge passage 126.

[0055] 3 and 7 , similar to the first compressor 120, the second compressor 130 includes a second eccentric shaft 131 provided integrally with the drive shaft 105, an annular second piston 132 (second rotor 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 drive shaft 105.

[0056] The second cylinder chamber 133 is a circular hole concentric with the center line CL1 of the drive shaft 105, and passes through the second cylinder 134. Relative rotation of the second cylinder 134 with respect to the rear head 70 is restricted. 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 perpendicular to the axial center line CL1 of the motor housing 60.

[0057] Furthermore, the second cylinder 134 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 peripheral surface of the second cylinder 134, thereby communicating the second cylinder chamber 133 with the intermediate chamber 71. The second discharge passage 136 opens to a second surface 134b of the second cylinder 134.

[0058] 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 tip of this second vane 137 is pressed against the outer peripheral surface of the second piston 132 by a second spring 138. The second vane 137 divides the second cylinder chamber 133 into a second suction chamber 133a and a second compression chamber 133b. The second suction chamber 133a is in communication with a second suction passage 135. The second compression chamber 133b is in communication with a second discharge passage 136. The second piston 132 revolves within the second cylinder chamber 133. The refrigerant introduced from the second suction passage 135 into the second suction chamber 133a (second cylinder chamber 133) is compressed by the revolution of the second piston 132 and is discharged from the second compression chamber 133b through the second discharge passage 136.

[0059] 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 drive shaft 105.

[0060] 4 and 5 , the first cylinder chamber 123 is closed on the partition block 80 side by a flat first closure plate 141. This first closure plate 141 is a separate member from the partition block 80 and is interposed between the partition block 80 and the first compressor 120. More specifically, the first closure 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. This first closure plate 141 has a discharge hole 141a that can communicate with the first discharge passage 126 of the first cylinder 124. This discharge hole 141a (through hole 141a) penetrates the first closure plate 141 in the plate thickness direction.

[0061] The partition block 80 has a suction passage 86 that penetrates a first mating surface 81 (first surface 81) facing the motor chamber 61 and a second mating surface 82 (second surface 82) facing the intermediate chamber 71. The suction port 125a of the first suction passage 125 is directly connected to the suction passage 86 of the partition block 80, thereby communicating with the motor chamber 61 via the suction passage 86. The first closing plate 141 is cut out so as not to be interposed between the suction port 125a and the suction passage 86. Therefore, the first cylinder chamber 123 communicates with the suction port 68 (see FIG. 2) of the motor housing 60 via the first suction passage 125, the suction passage 86 of the partition block 80, and the motor chamber 61.

[0062] An example of a configuration in which the suction port 125a is directly connected to the suction passage 86 is as follows. For example, the first cylinder 124 has a protrusion 124c that protrudes from the first surface 124a toward the second mating surface 82 of the partition block 80. The tip surface 124d of this protrusion 124c is a flat surface parallel to the first surface 124a of the first cylinder 124. This tip surface 124d is sometimes referred to as the "flange surface 124d." The suction port 125a opens to the flange surface 124d. A single seal member 129 seals the gap between this flange surface 124d and the second mating surface 82 of the partition block 80. As a result, the suction passage 86 and the suction port 125a can be sealed by the single seal member 129. The seal member 129 is formed of, for example, an O-ring, and is fitted into an O-ring groove 124e (see FIG. 5) formed in the flange surface 124d or the second mating surface 82. In this case, the first closing plate 141 is cut out so as not to interfere with the protrusion 124c (see FIG. 5).

[0063] On the other hand, if the suction passage connecting the suction passage 86 and the suction port 125a is provided in the first closure plate 141, a seal member will be required between the partition block 80 and the first closure plate 141, and between the first closure plate 141 and the first cylinder 124. This will increase the number of seal members, which is not a good idea.

[0064] Furthermore, the partition block 80 has a communication groove 87 (discharge recess 87) that connects the discharge hole 141a of the first closure plate 141 and the intermediate chamber 71. This communication groove 87 is formed in the second mating surface 82 of the partition block 80.

[0065] As shown in FIG. 4 , a discharge valve 88 is provided in the communication groove 87 to open and close the discharge hole 141 a. The discharge valve 88 is a check valve, such as a reed valve 89, that allows refrigerant to flow only from the first discharge passage 126 to the communication groove 87. The reed valve 89 is made up of a thin, elastic valve seat 89 a for opening and closing the discharge hole 141 a, a stopper 89 b for restricting the valve opening amount of the valve seat 89 a, and a fixing member 89 c for fixing one end of the valve seat 89 a and one end of the stopper 89 b. The first compression chamber 123 b of the first cylinder chamber 123 is in communication with the second cylinder chamber 133 via the first discharge passage 126, the discharge hole 141 a, the communication groove 87, the intermediate chamber 71, and the second suction passage 135 (see FIG. 3 ).

[0066] As is clear from the above description, the volume of the first discharge passage 126 of the first cylinder 124 and the volume of the discharge hole 141a of the first closure plate 141 constitute the dead volume of the compression chamber 123b. Here, the dead volume refers to the volume that does not contribute to the compression of the refrigerant in the first compression chamber 123b when the refrigerant is compressed by the first piston 122. To improve the performance of the first compressor 120, it is preferable that the dead volume be as small as possible. For example, in order to reduce the dead volume, it is more preferable that the first compression chamber 123b communicates directly with the discharge hole 141a of the first closure plate 141 without passing through the first discharge passage 126. The dead volume of the present invention is smaller than the dead volume that would be obtained if a hypothetical discharge passage 126v were to open radially outward from the first cylinder 124, as shown by imaginary lines in FIG. 4 .

[0067] Furthermore, the first closure plate 141 has a shaft through hole 141b through which the drive shaft 105 can pass. The diameter of the shaft through hole 141b is smaller than the outer diameter of the shaft seal 108. The first closure plate 141 restricts movement of the shaft seal 108 toward the open end of the shaft seal retaining hole 85 (the side toward the second mating surface 82 of the partition block 80).

[0068] 4, 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.

[0069] A sliding surface 141c of the first closing plate 141 overlaps the first surface 124a of the first cylinder 124. A sliding surface 142a of the second closing plate 142 overlaps the second surface 124b of the first cylinder 124. The first piston 122 is positioned so as to be slidable on the sliding surface 141c of the first closing plate 141 and the sliding surface 142a of the second closing plate 142. For example, the sliding surface 122a of the first piston 122 is slidable on the sliding surface 141c of the first closing plate 141.

[0070] 3, 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.

[0071] 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 .

[0072] 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 opening of 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 refrigerant gas 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 second 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.

[0073] It is preferable that the tip end of the drive shaft 105 is rotatably supported by a third bearing 146 provided on the third closure plate 143. The third bearing 146 is configured by a rolling bearing or a sliding bearing. More preferably, by using a rolling bearing for the third bearing 146, the drive shaft 105 can be rotatably supported more stably.

[0074] 8 , 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.

[0075] 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 80a of the partition block 80. The injection inlet 151 opens at this boss portion 154. The injection inlet 151 can introduce injection refrigerant gas by connecting the injection pipe 22 (see FIG. 1 ).

[0076] The injection outlet 152 is open to a second mating surface 82 (second flat surface 82) of the partition block 80 that faces the intermediate chamber 71, thereby communicating with the intermediate chamber 71. Therefore, the injection outlet 152 can lead out the injected refrigerant gas to the intermediate chamber 71.

[0077] A check valve 160 is provided at the injection outlet 152. This check valve 160 allows the injection refrigerant gas to flow only from the injection passage 153 to the intermediate chamber 71. In other words, when the pressure in the injection passage 153 increases to exceed the pressure in the intermediate chamber 71, the check valve 160 opens due to the pressure difference.

[0078] The check valve 160 is provided on the flat second mating surface 82 of the partition block 80, which faces the intermediate 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 refrigerant gas to flow from the injection passage 153 to the intermediate chamber 71.

[0079] Next, the flow of refrigerant within the electric compressor 50 will be described. As shown in Figures 2 and 3, 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, thereby cooling the motor 100, and then flows into the suction passage 86 of the partition block 80. The refrigerant that has passed through the suction passage 86 passes through the first suction passage 125 of the first compressor 120 and enters the first suction chamber 123a.

[0080] 3, refrigerant compressed by the first compressor 120 flows from the first compression chamber 123b to the second suction chamber 133a through the first discharge passage 126, the discharge hole 141a of the first closing plate 141, the communicating groove 87 of the partition block 80, the intermediate chamber 71, and the second suction passage 135. Refrigerant further compressed by the second compressor 130 flows from the second compression chamber 133b to the second discharge passage 136, the communicating hole 143a of the third closing plate 143, the discharge chamber 144, and the oil separation chamber 74, and then to the discharge port 75 of the rear head 70.

[0081] Second Embodiment An electric compressor 250 according to a second embodiment will be described with reference to Fig. 9. Fig. 9 corresponds to Fig. 3 described above.

[0082] The electric compressor 250 of the second embodiment is characterized in that the two-stage compression mechanism 110 (multiple-stage compression mechanism 110) of the electric compressor 50 of the first embodiment shown in Figures 2 to 8 is changed to a twin compression mechanism 260 (parallel compression mechanism 260) shown in Figure 9. The other configurations of the electric compressor 250 and the injection-type refrigeration cycle 10, 30 including this electric compressor 250 are common to the electric compressor 50 of the first embodiment and the injection-type refrigeration cycle 10, 30 including this electric compressor 50. The same reference numerals are used for the parts common to the electric compressor 50 of the first embodiment and the injection-type refrigeration cycle 10, 30 including this electric compressor 50, and detailed description thereof will be omitted.

[0083] More specifically, the electric compressor 250 includes a compression mechanism 260. This compression mechanism 260 is a multiple-compressor configuration including a first compressor 120 and a second compressor 130. This compression mechanism 260 is characterized in that it has two compressors 120, 130 arranged in parallel to perform compression. This compression mechanism 260 may be referred to as a "twin compression mechanism 260" or a "parallel compression mechanism 260" as appropriate. The thickness of the cylinder 124 of the first compressor 120 may be the same as the thickness of the cylinder 134 of the second compressor 130.

[0084] This twin compression mechanism 260 is characterized in that both the first suction passage 125 of the first compressor 120 and the second suction passage 135 of the second compressor 130 are connected to the suction passage 86 of the partition block 80. More specifically, the second suction passage 135 of the second compressor 130 is in communication with the suction passage 86 through the suction port 125a of the first suction passage 125. Therefore, both the first suction passage 125 and the second suction passage 135 are converged at the suction port 125a and are directly connected to the suction passage 86 through this suction port 125a, thereby communicating with the motor chamber 61 via the suction passage 86 of the partition block 80.

[0085] Furthermore, in the second embodiment, the first discharge passage 126 of the first compressor 120 is not connected from the intermediate chamber 71 to the second suction passage 135 of the second compressor 130, but is directly connected to the discharge chamber 144 through the communication hole 271 of the rear head 70.

[0086] Next, the flow of refrigerant within the electric compressor 250 will be described. After cooling the motor 100, the refrigerant flows into the suction passage 86 of the partition block 80. The refrigerant passes through the first suction passage 125 of the first compressor 120 to enter the first suction chamber 123a and the second suction passage 135 of the second compressor 130 to enter the second suction chamber 133a. The refrigerant compressed by the first compressor 120 flows from the first compression chamber 123b through the first discharge passage 126, the discharge hole 141a of the first closing plate 141, the communication groove 87 of the partition block 80, the intermediate chamber 71, and the communication hole 271 of the rear head 70 to the discharge chamber 144. The refrigerant compressed by the second compressor 130 flows from the second compression chamber 133b through the second discharge passage 136 and the communication hole 143a of the third closing plate 143 to the discharge chamber 144.

[0087] The above description of the first and second embodiments can be summarized as follows.

[0088] 2 and 9, the electric compressor 50, 250 includes a compression mechanism 110, 260, a drive shaft 105 that drives the compression mechanism 110, 260, a motor 100 that drives the drive shaft 105, a motor housing 60 having a motor chamber 61 that houses the motor 100, a rear head 70 having an intermediate chamber 71 that houses the compression mechanism 110, 260, a partition block 80 located between the rear head 70 and the motor housing 60, separating the intermediate chamber 71 from the motor chamber 61, and having a shaft through-hole 83 through which the drive shaft 105 can pass, and a bearing 106 (first bearing 106) fixed to the partition block 80 and rotatably supporting the drive shaft 105. A closing plate 141, which is a separate member from the partition block 80, is interposed between the partition block 80 and the compression mechanism 110, 260.

[0089] The drive shaft 105 of the electric compressor 50 / 250 rotates at high speed. The bearing 106 supporting this drive shaft 105 is required to fit snugly into the fitting hole 84a (see FIG. 4) of the bearing fixing portion 84. For this reason, the bearing 106 is fixed to the fitting hole 84a of the bearing fixing portion 84 by press-fitting (e.g., interference fit). In this case, deformation (distortion) due to the press-fitting may occur in the partition block 80. Furthermore, the bearing 106 and the bearing fixing portion 84 are subjected to radial loads associated with the loads from the motor 100 and the compression mechanism 110 / 260. In this case, deformation (distortion) due to the radial load may occur in the partition block 80. As shown in FIG. 4, the partition block 80 has a mating surface 82 (second mating surface 82) that faces the rotating body 122 of the compression mechanism 110 / 260. Care must be taken to ensure that deformation (distortion) caused by the bearing 106 on the mating surface 82 does not affect the rotation of the rotating body 122 .

[0090] In contrast, in the present invention, a closure plate 141, which is a separate member from the partition block 80, is interposed between the partition block 80 and the compression mechanism 110; 260. As a result, the closure plate 141 blocks the transmission of deformation (strain) between the partition block 80 and the compression mechanism 110; 260. Even if deformation (strain) of the partition block 80 occurs due to the bearing 106, the sliding surface 141c of the closure plate 141, on which the rotating body 122 (first rotating body 122, first piston 122) of the compression mechanism 110; 260 slides, can be maintained as flat as possible. As a result, the sliding surface 122a of the rotating body 122 can slide smoothly against the sliding surface 141c of the closure plate 141, ensuring the performance and durability of the compression mechanism 110; 260.

[0091] 4 and 9 , the bearing 106 (first bearing 106) is located on the opposite side (motor chamber 61 side) of the partition block 80 from the compression mechanism 110; 260. In this way, in the partition block 80, the bearing 106 is disposed on the opposite side from the compression mechanism 110; 260, so that deformation of the bearing 106 due to press-fitting or radial load can be prevented from being transmitted to the sliding surface 141c on which the rotating body 122 (first rotating body 122, first piston 122) of the compression mechanism 110; 260 slides.

[0092] As shown in Figures 4 and 9, the compression mechanism 110; 260 (first compressor 120) is a rolling piston type rotary compressor including a cylinder 124 (first cylinder 124) that forms a cylinder chamber 123 (first cylinder chamber 123) and a piston 122 (first piston 122) that performs eccentric rotational motion within the cylinder chamber 123. The piston 122 is positioned so as to be able to slide relative to the sliding surface 141c of the closure plate 141. In this way, the piston 122 of the rolling piston type rotary compressor 120 slides relative to the closure plate 141 rather than the partition block 80, and is therefore not affected by deformation due to press-fitting of the bearing 106 into the partition block 80 or radial load.

[0093] 3 and 9, the compression mechanism 110; 260 is a multiple-compressor configuration including a first compressor 120 and a second compressor 130, and can reduce the compression ratio of each compressor 120, 130 compared to a single-stage compression mechanism (single-cylinder mechanism). Moreover, as shown in Fig. 7, the center line CL2 of the first eccentric shaft 121 of the first compressor 120 and the center line CL3 of the second eccentric shaft 131 of the second compressor 130 can be disposed symmetrically with respect to the center line CL1 of the drive shaft 105.

[0094] As described above, the compression mechanism 110 / 260 is configured with multiple compressors, and the rotation phases of the pistons 122, 132 are different, so that intake and compression timing alternate in the cylinders 123, 134. For example, when the first compression mechanism 120 performs an intake operation, the second compressor 130 performs a compression operation. Because the directions of the compression reaction forces of the compressors 120, 130 are different, the radial loads acting on the drive shaft 105 are canceled out. This significantly reduces the radial load (support load) supported by the bearing 106. Because the radial load supported by the bearing 106 and the bearing fixing portion 84 is reduced, deformation of the partition block 80 supporting this radial load can be reduced. As a result, transmission of deformation from the partition block 80 to the sliding surface 141c of the first closure plate 141 can be further prevented. Therefore, the generation of vibrations and noise from the electric compressor 50 can be suppressed, and the reliability of the electric compressor 50; 250 can be further improved.

[0095] 4 and 9 , the first compressor 120 is located closer to the partition block 80 than the second compressor 130. The compression chamber 123b (first compression chamber 123b) of the first compressor 120 is in communication with the discharge chamber 144 via at least a discharge hole 141a provided in the closure plate 141 (first closure plate 141), a discharge valve 88 that opens and closes the discharge hole 141a, a discharge recess 87 provided in the partition block 80, and the intermediate chamber 71. In this way, by providing the discharge hole 141a of the first compressor 120 in the closure plate 141, the dead volume of the compression chamber 123b of the first compressor 120 can be reduced, which can contribute to improving the performance of the compression mechanism 110.

[0096] 4 and 9, the partition block 80 has a shaft seal retaining hole 85 that is positioned concentrically with the shaft through-hole 83, at CL1. This shaft seal retaining hole 85 opens to the closing plate 141 side of the partition block 80 and retains a shaft seal 108 that seals between the shaft through-hole 83 and the drive shaft 105. Movement of this shaft seal 108 toward the open end of the shaft seal retaining hole 85 is restricted by the closing plate 141.

[0097] In this way, the gap between the shaft through hole 83 and the drive shaft 105 is sealed by the shaft seal 108, so that the refrigerant present in the intermediate chamber 71 is prevented from leaking into the motor chamber 61 through the shaft through hole 83. Furthermore, the closing plate 141 prevents the shaft seal 108 from moving in the axial direction of the drive shaft 105, which further prevents wear of the shaft seal 108.

[0098] 4 and 9 , the partition block 80 has a suction passage 86 that penetrates a first surface 81 (first mating surface 81) facing the motor chamber 61 and a second surface 82 (second mating surface 82) facing the intermediate chamber 71. The first compressor 120 has a suction port 125a that can draw in refrigerant. The suction port 125a is directly connected to the suction passage 86, and is thereby in communication with the motor chamber 61 via the suction passage 86.

[0099] Since the suction passage 86 of the partition block 80 is directly connected to the suction port 125a of the first compressor 120, the suction passage 86 of the partition block 80 and the suction port 125a of the first compressor 120 can be sealed with a single seal member 129. Therefore, the number of seal members 129 required can be reduced.

[0100] As long as the functions and effects of the present invention are achieved, the present invention is not limited to Examples 1 and 2. For example, the compression mechanism 110 may be configured as a multi-stage compression mechanism in which multiple compressors are arranged in series for compression. Also, the compression mechanism 260 may be configured as a parallel compression mechanism in which multiple compressors are arranged in parallel for compression. For example, although Examples 1 and 2 have been described using the injection-type refrigeration cycle 10 as the refrigeration cycle, the refrigeration cycle may be a refrigeration cycle that does not introduce injection refrigerant gas.

[0101] The electric compressors 50 and 250 of the present invention are suitable for use in the refrigeration cycles 10 and 30 .

[0102] 50 Electric compressor 60 Motor housing 61 Motor chamber 70 Rear head 71 Intermediate chamber 80 Partition block 81 First surface (first mating surface) 82 Second surface (second mating surface) 83 Shaft through hole 84 Bearing fixing portion 85 Shaft seal retaining hole 86 Suction passage 87 Discharge recess (communicating groove) 88 Discharge valve 100 Motor 105 Drive shaft 106 Bearing (first bearing) 108 Shaft seal 110 Compression mechanism (two-stage compression mechanism) 120 First compressor 122 Rotating body (first rotating body, first piston) 123 Cylinder chamber (first cylinder chamber) 123b Compression chamber (first compression chamber) 124 Cylinder (first cylinder) 125 Suction passage (first suction passage) 125a Suction port 130 Second compressor 141 Closure plate (first closure plate) 141a Discharge hole 141c Sliding surface 250 Electric compressor 260 Compression mechanism (twin compression mechanism) CL1 Center line

Claims

1. A compressor mechanism (110; 260), a drive shaft (105) for driving the compressor mechanism (110; 260), a motor (100) for driving the drive shaft (105), a motor housing (60) having a motor chamber (61) for housing the motor (100), a rear head (70) having an intermediate chamber (71) for housing the compressor mechanism (110; 260), a partition block (80) located between the rear head (70) and the motor housing (60), partitioning the intermediate chamber (71) and the motor chamber (61), and having a shaft through-hole (83) through which the drive shaft (105) can pass, and a bearing (106) fixed to the partition block (80) and rotatably supporting the drive shaft (105), wherein a closing plate (141) made of a member different from the partition block (80) is interposed between the partition block (80) and the compressor mechanism (110; 260). An electric compressor (50; 250) characterized by this.

2. The electric compressor according to claim 1, wherein the bearing (106) is located on the side of the partition block (80) opposite to the compressor mechanism (110; 260).

3. The compressor mechanism (110; 260) is a rolling piston type rotary compressor including a cylinder (124) forming a cylinder chamber (123) and a piston (122) performing an eccentric rotational motion within the cylinder chamber (123), and the piston (122) is slidably positioned with respect to a sliding surface (141c) of the closing plate (141). The electric compressor according to claim 1.

4. The compressor mechanism (110; 260) is a configuration of a multi-compressor including a first compressor (120) and a second compressor (130). The electric compressor according to claim 1.

5. The first compressor (120) is located closer to the partition block (80) than the second compressor (130), and a compression chamber (123b) of the first compressor (120) communicates with a discharge chamber (144) via at least a discharge hole (141a) in the closing plate (141), a discharge valve (88) for opening and closing the discharge hole (141a), a discharge recess (87) in the partition block (80), and the intermediate chamber (71). The electric compressor according to claim 4.

6. The partition block (80) has a shaft seal holding hole (85) that is concentric with the shaft through hole (83), and the shaft seal holding hole (85) opens on the side of the partition block (80) facing the closing plate (141) and holds a shaft seal (108) that seals between the shaft through hole (83) and the drive shaft (105). The movement of the shaft seal (108) toward the open end side of the shaft seal holding hole (85) is restricted by the closing plate (141). The electric compressor according to claim 1.

7. The partition block (80) has a suction passage (86) that penetrates a first surface (81) facing the motor chamber (61) and a second surface (82) facing the intermediate chamber (71). The first compressor (120) has a suction port (125a) capable of sucking refrigerant, and the suction port (125a) is directly connected to the suction passage (86) and communicates with the motor chamber (61) through the suction passage (86). The electric compressor according to claim 4.

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