Electrical compressor

Abstract

To support a drive shaft stably with a bearing fixed to a partitioning block and secure 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) from 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).SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Among electric compressors, there is a rolling piston type rotary compressor including a compression mechanism having a plurality of compressors. Such compression mechanisms include a multi-stage compression mechanism that compresses a plurality of compressors arranged in series and a parallel compression mechanism (for example, a twin compression mechanism) that compresses a plurality of compressors arranged in parallel. As an electric compressor including a multi-stage compression mechanism, for example, the technology of Patent Document 1 is known.

[0003] According to the technology known in Patent Document 1, inside the housing, a high-stage compression element is arranged under the motor, and a low-stage compression element is arranged under the high-stage compression element, which is a configuration of a so-called vertically arranged electric compressor.

[0004] This electric compressor is provided with a drive shaft that transmits the power of the motor to the high-stage compression element and the low-stage compression element. This 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. A rolling piston type rotary compressor generally has a structure that supports the drive shaft by a sliding bearing.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An electric compressor is used, for example, in a vehicle air conditioner. The electric compressor used in a vehicle air conditioner is required to rapidly cool a high-temperature vehicle interior in summer and to cool the battery temperature of an electric vehicle to be constant during rapid charging, and there is a requirement to operate at high speed. Therefore, it is considered to use a rolling bearing such as a ball bearing that can cope with high-speed rotation for the electric compressor of the vehicle air conditioner.

[0007] However, in order to use a rolling bearing, fitting by press-fitting to fix between the bearing support member and the rolling bearing is required. In particular, for the rolling bearing disposed between the motor and the high-stage compression element, it is necessary to use a relatively large rolling bearing compared to other rolling bearings.

[0008] When this large rolling bearing is used in the electric compressor of Patent Document 1, this bearing is 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, when the upper bearing member is deformed by press-fitting, the piston sliding surface is also deformed and cannot maintain a flat surface. As a result, it is considered that abnormal wear occurs on the piston sliding surface and the piston, leading to performance degradation and reliability degradation. This also has the same problem in an electric compressor having a parallel compression mechanism.

[0009] The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a technique capable of stably supporting a drive shaft by a bearing fixed to a partition block and ensuring the performance and durability of a compression mechanism.

Means for Solving the Problems

[0010] In the following description, for easy understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated forms by that.

[0011] According to the present disclosure, first, A compression mechanism (110; 260), a drive shaft (105) for driving the compression 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 compression mechanism (110; 260), and a partition block (80) positioned 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). A closing plate (141) made of a member different from the partition block (80) is interposed between the partition block (80) and the compression mechanism (110; 260). An electric compressor (50; 250) is provided, characterized by this.

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

[0013] Third, preferably, the electric compressor according to the first and second aspects, wherein 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 an eccentric rotational motion within the cylinder chamber (123). The piston (122) is positioned slidably with respect to the sliding surface (141c) of the closing plate (141).

[0014] Fourth, preferably, the electric compressor according to the first to third aspects, wherein the compression mechanism (110; 260) has a configuration of a plurality of compressors including a first compressor (120) and a second compressor (130).

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

[0016] Sixthly, preferably, the electric compressor according to the first to fifth aspects, wherein the partition block (80) has a shaft seal holding hole (85) located concentrically with respect to the shaft through hole (83), 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) for sealing 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).

[0017] Seventhly, preferably, the electric compressor according to the first aspect, wherein 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 sucking refrigerant, The suction port (125a) is directly connected to the suction passage (86), and communicates with the motor chamber (61) via the suction passage (86).

Advantages of the Invention

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

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0020] Embodiments of 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] <Example 1> While referring to FIGS. 1 to 8, the electric compressor 50 of Example 1 and the injection type refrigeration cycles 10 and 30 including this electric compressor 50 will be described.

[0022] FIG. 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 conditioner, and performs cooling and heating by an indoor air conditioning unit (not shown). Note that this refrigeration cycle 10 is not limited in its application. Also, this refrigeration cycle 10 is suitable for using R744 refrigerant, but other refrigerants (e.g., R134a refrigerant and R1234yf refrigerant) can be used.

[0023] Here, the injection type means that in the refrigeration cycle 10, the high-pressure refrigerant is expanded in two stages, and the refrigerant gas (vapor-phase refrigerant) separated into gas and liquid at the intermediate pressure is returned to the electric compressor 50. The refrigerant gas at the intermediate pressure returned to the electric compressor 50 is called the 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. This two-stage compression mechanism 110 has a first compressor 120 and a second compressor 130. Further, the electric compressor 50 includes a suction port 68 capable of sucking refrigerant from the outside (evaporator 11), a discharge port 75 capable of discharging refrigerant to the outside (gas cooler 12), and an injection port 151 capable of introducing injection refrigerant gas.

[0026] The refrigerant outlet of the gas cooler 12 is connected to the refrigerant inlet of the gas-liquid separator 15 via the first flow path 21 and the first expansion valve 13. The refrigerant outlet of the gas-liquid separator 15 is connected to an injection pipe 22 through which the injection refrigerant gas flows and a second flow path 23 through which the refrigerant liquid flows. The injection pipe 22 is connected to the injection port 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 by 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 by the fourth flow path 25.

[0028] The refrigerant flows in the direction indicated by the solid line in FIG. 1A. That is, the refrigerant heat-exchanged with the outside air by the gas cooler 12 flows through the first flow path 21, the first expansion valve 13, the gas-liquid separator 15, the second expansion valve 14, and the evaporator 11 to the suction port 68 of the electric compressor 50 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 through the fourth flow path 25.

[0029] In this way, the refrigerant heat-exchanged 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. That is, the refrigerant discharged from 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 only through the first expansion valve 13 of the two expansion valves 13 and 14 flows through the gas-liquid separator 15 and is led to the injection inlet 151 of the electric compressor 50 by the injection pipe 22. By appropriately adjusting the opening degrees of the first expansion valve 13 and the second expansion valve 14 according to the operating requirements, the amount branched to the injection inlet 151 of the compressor 50 can be adjusted.

[0031] Figure 1B shows another example of an injection-type refrigeration cycle 30 (hereinafter abbreviated as "refrigeration cycle 30"). This alternative refrigeration cycle 30 is provided with an internal heat exchanger 31 instead of the gas-liquid separator 15 of the refrigeration cycle 10. The refrigerant outlet of the gas cooler 12 is connected to the refrigerant inlet of the internal heat exchanger 31 by the first flow path 21. Among the first flow path 21, the section 21a between the gas cooler 12 and the internal heat exchanger 31, that is, the branch point 21a, branches off by the branch path 41 and is connected to the inlet of the internal heat exchanger 31 via the first expansion valve 13. The outlet of the internal heat exchanger 31 is connected to the injection inlet 151 of the electric compressor 50 by the injection pipe 22.

[0032] In the alternative refrigeration cycle 30, the refrigerant branched from the section 21a between the gas cooler 12 and the internal heat exchanger 31, that is, the branch point 21a, is adiabatically expanded by the first expansion valve 13, then heated by the internal heat exchanger 31, and the heated refrigerant gas is caused to flow to the injection inlet 151 of the electric compressor 50 through the injection pipe 22.

[0033] Next, the overall configuration of the electric compressor 50 will be described. As shown in Figure 2, this electric compressor 50 has a configuration of a so-called horizontally-mounted electric compressor in which a two-stage compression mechanism 110 is arranged beside, for example, a motor 100. This electric compressor 50 includes a housing 51, a motor 100, a drive shaft 105 driven by the motor 100, and a two-stage compression mechanism 110 driven by this drive shaft 105.

[0034] The housing 51 is configured to be installable horizontally. This housing 51 includes 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 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 of castings of metal materials such as aluminum (including aluminum alloys).

[0035] The motor housing 60 is a bottomed cylindrical member. One axial end of the motor housing 60 is closed by a bottom wall 62. This bottom wall 62 is integrally formed with the motor housing 60, for example. The other axial end of the motor housing 60 is entirely open. The open end face 63 of the motor housing 60 may be referred to as the first end face 63. This first end face 63 is a flat surface orthogonal 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 assembled to the outer wall surface 62a of the bottom wall 62 of the motor housing 60. An inverter device 66 for supplying driving power to the motor 100 is housed in this inverter housing 65.

[0036] Furthermore, the motor housing 60 has a suction port 68 for sucking refrigerant from the outside into the motor chamber 61. More specifically, a boss portion 69 protruding radially outward is provided on the outer peripheral surface 60a of the motor housing 60. The suction port 68 opens in this boss portion 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 bottomed cylindrical member. One axial end of the rear head 70 is closed by a bottom wall 72. This bottom wall 72 is integrally formed with the rear head 70, for example. The other axial end of the rear head 70 is entirely open. The open end face 73 of the rear head 70 may be referred to as the second end face 73. This second end face 73 is a flat surface orthogonal to the axial center line CL1 of the motor housing 60 and faces the first end face 63 side of the motor housing 60. The inside of the rear head 70 is formed as an intermediate chamber 71.

[0038] Furthermore, the rear head 70 has an oil separation chamber 74 that separates oil from the refrigerant compressed by the two-stage compression mechanism 110, and a discharge port 75 that discharges the gaseous refrigerant from which the oil has been separated by the oil separation chamber 74 to the outside. The fourth flow path 25 (refrigerant discharge pipe 25) shown in FIG. 1 is connected to the discharge port 75.

[0039] The partition block 80 is a disk-shaped member that is located between the motor housing 60 and the rear head 70 and partitions the motor chamber 61 and the intermediate chamber 71. That is, the partition block 80 is sandwiched between the first end face 63 of the motor housing 60 and the second end face 73 of the rear head 70.

[0040] 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 chamber 71. The first mating surface 81 and the second mating surface 82 are flat surfaces orthogonal to the axial center line CL1 of the motor housing 60. The first mating surface 81 and the second mating surface 82 may be appropriately referred to as the "first flat surface 81 and the second flat surface 82".

[0041] Between the first end face 63 of the motor housing 60 and the first mating surface 81 of the partition block 80, and between the second end face 73 of the rear head 70 and the second mating surface 82 of the partition block 80, they are each sealed by a sealing member (not shown) such as a gasket or an O-ring. The partition block 80 is restricted from both relative rotation and relative axial movement with respect to the motor housing 60 and the rear head 70. For example, the partition block 80 is integrally fixed together with the motor housing 60 and the rear head 70 by a fastening member 91 such as a bolt.

[0042] Next, the motor 100 will be described. As shown in Fig. 2, the motor 100 includes an output shaft 101 (motor shaft 101), a rotor 102 fixed to the output shaft 101, and a cylindrical stator 103 surrounding the rotor 102. The rotor 102 is rotatable together with the output shaft 101. The stator 103 is disposed radially outside the rotor 102 and fixed to the inner peripheral surface 60b of the motor housing 60.

[0043] The drive shaft 105 of the present invention includes both a configuration (see Fig. 2) in which it also serves as the output shaft 101 of the motor 100 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 configured as 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] This drive shaft 105 (output shaft 101) rotates about 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. Thus, 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 on the partition block 80 and a second bearing 107 provided on the bottom wall 62 of the motor housing 60. The first bearing 106 is located on the side of the partition block 80 opposite to the compression mechanism 110 (the side of the first mating surface 81). The first bearing 106 and the second bearing 107 are constituted by rolling bearings or sliding bearings. More preferably, by adopting rolling bearings for the first bearing 106 and the second bearing 107, the drive shaft 105 can be supported more stably rotatably, and the eccentric load of the drive shaft 105 that deforms (distorts) the partition block 80 can be reduced, so that the deformation transmission to the sliding surface 141c (piston sliding portion 141c) of the first closing plate 141 described later can be prevented.

[0046] As shown in FIGS. 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 for fixing the first bearing 106, and a shaft seal holding hole 85 for holding the shaft seal 108. The through hole 83 of the shaft, the fitting hole 84a of the bearing fixing portion 84, and the shaft seal holding hole 85 are located on the center line CL1 of the drive shaft 105.

[0047] The bearing fixing portion 84 protrudes toward the motor chamber 61 from the first mating surface 81 of the partition block 80. The outer peripheral surface 106a of the first bearing 106 is fixed to the fitting hole 84a of the bearing fixing portion 84 by press fitting (for example, shrink fitting).

[0048] The shaft seal holding hole 85 opens to the second mating surface 82 (the side of the two-stage compression mechanism 110) 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 constituted by, for example, a lip seal. This shaft seal 108 prevents the refrigerant existing in the intermediate chamber 71 from leaking into the motor chamber 61 through the shaft through hole 83.

[0049] Next, the compression mechanism 110 will be described. As shown in FIG. 3, the compression mechanism 110 is configured as 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 by arranging two compressors 120 and 130 in series. The first compressor 120 and the second compressor 130 that constitute this two-stage compression mechanism 110 are both of the so-called rolling piston type rotary compressor configured to compress by a rotating body 122, 132 (pistons 122, 132) that rotate and cylinders 124, 134. That is, the first compressor 120 and the second compressor 130 include cylinders 124, 134 that form cylinder chambers 123, 133, and pistons 122, 132 that perform an eccentric rotational motion 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 side of the partition block 80 in the intermediate chamber 71. The second compressor 130 is located on the side of the bottom wall 72 of the rear head 70 in the intermediate chamber 71. That is, the first compressor 120 is located on the side of the partition block 80 rather than the second compressor 130.

[0051] More specifically, as shown in FIGS. 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 rotating body 122) fitted to the first eccentric shaft 121, and a flat plate-shaped first cylinder 124 that forms a first cylinder chamber 123 that allows the rotational motion of the first piston 122. The center line CL2 of the first eccentric shaft 121 is offset with respect to the center line CL1 of the drive shaft 105. Thereby, the first piston 122 performs an eccentric rotational motion within the first cylinder chamber 123.

[0052] The first cylinder chamber 123 is a perfect circular hole concentric with the center line CL1 of the drive shaft 105, and penetrates the first cylinder 124. The 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 side of the partition block 80 and a second surface 124b facing the second cylinder 134 side of the second compressor 130. The first surface 124a and the second surface 124b of the first cylinder 124 are flat surfaces orthogonal to the axial center line CL1 of the motor housing 60. Further, the first cylinder 124 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] As shown in FIG. 4, the first discharge passage 126 opens to the first surface 124a of the first cylinder 124. That is, 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 along the inner wall surface 123c forming the first cylinder chamber 123 of the first cylinder 124 up to the first surface 124a.

[0054] As shown in FIGS. 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 so as to be able to advance and retreat. 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 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 communicates with the first suction passage 125. The first compression chamber 123b communicates with the first discharge passage 126. The first piston 122 revolves within the first cylinder chamber 123. The refrigerant introduced from the first suction passage 125 into the first suction chamber 123a (the first cylinder chamber 123) is compressed by the revolving motion of the first piston 122 and discharged through the first discharge passage 126 from the first compression chamber 123b.

[0055] As shown in FIGS. 3 and 7, similar to the first compressor 120, the second compressor 130 includes a second eccentric shaft 131 integrally provided on the drive shaft 105, an annular second piston 132 (second rotating body 132) fitted to the second eccentric shaft 131, and a flat-plate-shaped second cylinder 134 having a second cylinder chamber 133 that allows the rotational movement of the second piston 132. The center line CL3 of the second eccentric shaft 131 is offset with respect to the center line CL1 of the drive shaft 105.

[0056] The second cylinder chamber 133 is a perfect circular hole concentric with the center line CL1 of the drive shaft 105 and penetrates the second cylinder 134. The relative rotation of the second cylinder 134 with respect to the rear head 70 is restricted. Further, the second cylinder 134 has a first surface 134a facing the second surface 124b side of the first cylinder 124 and a second surface 134b facing the bottom wall 72 side of the rear head 70. The first surface 134a and the second surface 134b of the second cylinder 134 are flat surfaces orthogonal 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 that communicate with the second cylinder chamber 133. The second suction passage 135 communicates the second cylinder chamber 133 with the intermediate chamber 71 by opening to the outer peripheral surface of the second cylinder 134. The second discharge passage 136 opens to the 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 so as to be able to advance and retreat. 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 vane 137 partitions the second cylinder chamber 133 into a second suction chamber 133a and a second compression chamber 133b. The second suction chamber 133a communicates with a second suction passage 135. The second compression chamber 133b communicates 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 (the second cylinder chamber 133) is compressed by the revolving motion of the second piston 132 and 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 symmetric positions with respect to the center line CL1 of the drive shaft 105.

[0060] As shown in FIGS. 4 and 5, the first cylinder chamber 123 is closed on the partition block 80 side by a flat plate-shaped first closing plate 141. The first closing 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 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. The first closing 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 in the plate thickness direction of the first closing plate 141.

[0061] The partition block 80 has an intake passage 86 that penetrates through 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 intake passage 125 is directly connected to the intake passage 86 of the partition block 80, thereby communicating with the motor chamber 61 via the intake passage 86. The first closing plate 141 is notched so as not to intervene between the suction port 125a and the intake 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 intake passage 125, the intake passage 86 of the partition block 80, and the path of the motor chamber 61.

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

[0063] On the other hand, when the intake passage connecting the intake passage 86 and the suction port 125a is provided in the first closing plate 141, seal members are required between the partition block 80 and the first closing plate 141, and between the first closing plate 141 and the first cylinder 124, respectively. This increases the number of seal members, which is not a good solution.

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

[0065] As shown in FIG. 4, a discharge valve 88 for opening and closing the opening of the discharge hole 141a is provided in the communication groove 87. This discharge valve 88 is constituted by a check valve, for example, a reed valve 89 that allows the flow of refrigerant only from the first discharge passage 126 to the communication groove 87. This reed valve 89 is constituted by a thin plate-like valve sheet 89a having elasticity for opening and closing the discharge hole 141a, a stopper 89b for regulating the valve opening amount of the valve sheet 89a, and a fixing member 89c for fixing one end portion of each of the valve sheet 89a and the stopper 89b. The first compression chamber 123b of the first cylinder chamber 123 communicates with the second cylinder chamber 133 via the paths of the first discharge passage 126, the discharge hole 141a, 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 closing plate 141 are the dead volumes of the compression chamber 123b. Here, the dead volume means the volume that does not contribute to compression when the refrigerant in the first compression chamber 123b is compressed by the first piston 122, and it is preferably as small as possible in order to improve the performance of the first compressor 120. For example, it is more preferable that the first compression chamber 123b communicates directly with the discharge hole 141a of the first closing plate 141 without passing through the first discharge passage 126 in order to reduce the dead volume. The dead volume of the present invention can be made smaller, for example, compared to the dead volume in the case where a hypothetical discharge passage 126v that opens radially outside the first cylinder 124 is assumed as shown by the imaginary line in FIG. 4.

[0067] Furthermore, this first closing plate 141 has a shaft through-hole 141b that can penetrate the drive shaft 105. The diameter of this shaft through-hole 141b is smaller than the outer diameter of the shaft seal 108. The movement of the shaft seal 108 toward the open end side of the shaft seal holding hole 85 (the second mating surface 82 side of the partition block 80) is restricted by the first closing plate 141.

[0068] As shown in FIG. 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] The sliding surface 141c of the first closing plate 141 overlaps with the first surface 124a of the first cylinder 124. The sliding surface 142a of the second closing plate 142 overlaps with the second surface 124b of the first cylinder 124. The first piston 122 is positioned slidably with respect to 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 with respect to the sliding surface 141c of the first closing plate 141.

[0070] As shown in FIG. 3, the second cylinder chamber 133 is closed on the bottom wall 72 side of the rear head 70 by a flat third closing plate 143. This third closing plate 143 covers the entire second surface 134b of the second cylinder 134. Furthermore, the third closing plate 143 is restricted from moving toward the bottom wall 72 side of the rear head 70 by the stepped surface 76 inside 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 clamped in the axial direction of the rear head 70 by the stepped surface 76 of the rear head 70 and the partition block 80.

[0072] Inside the rear head 70, a discharge chamber 144 partitioned by a bottom wall 72 and a third closing plate 143 is formed. The third closing plate 143 has a communication hole 143a that communicates the second discharge passage 136 of the second cylinder 134 with the discharge chamber 144. Inside the discharge chamber 144, a discharge valve 145 that opens and closes the opening of the through hole 143a is provided. This discharge valve 145 is a check valve, for example, a reed valve configured to allow the flow of refrigerant gas only from the second discharge passage 136 to the discharge chamber 144. The discharge chamber 144 communicates with the oil separation chamber 74. The refrigerant in the 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 of the drive shaft 105 is rotatably supported by a third bearing 146 provided on the third closing plate 143. The third bearing 146 is composed of a rolling bearing or a sliding bearing. More preferably, by adopting a rolling bearing for the third bearing 146, the drive shaft 105 can be supported more stably and rotatably.

[0074] As shown in FIG. 8, the partition block 80 has an injection inlet 151, an injection outlet 152, and an injection passage 153. The injection passage 153 communicates the injection inlet 151 and the injection outlet 152. At least the injection outlet 152 and the injection passage 153 are disposed inside the partition block 80.

[0075] The injection inlet 151 is, for example, integrally formed with the partition block 80. Specifically, on the outer peripheral surface 80a of the partition block 80, a boss portion 154 protruding radially outward is provided. The injection inlet 151 opens in this boss portion 154. The injection inlet 151 can introduce injection refrigerant gas by connecting an injection pipe 22 (see FIG. 1).

[0076] The injection outlet 152 communicates with the intermediate chamber 71 by opening into the second mating surface 82 (second flat surface 82) of the partition block 80 facing the intermediate chamber 71. For this reason, the injection outlet 152 can lead the injection refrigerant gas into the intermediate chamber 71.

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

[0078] This check valve 160 is provided on the flat second mating surface 82 of the partition block 80 facing the intermediate chamber 71. This check valve 160 is constituted by, for example, a reed valve 161. One end of a plate having a thin elasticity of this reed valve 161 is fixed and it opens only in one direction, that is, only in the direction allowing the flow of the injection refrigerant gas from the injection passage 153 to the intermediate chamber 71.

[0079] Next, the flow action of the refrigerant in the electric compressor 50 will be described. As shown in FIGS. 2 and 3, the refrigerant sucked from the suction port 68 of the motor housing 60 cools the motor 100 by passing through the gap of the motor 100 disposed in the motor chamber 61, and then flows into the suction passage 86 of the partition block 80. The refrigerant that has passed through this suction passage 86 enters the first suction chamber 123a through the first suction passage 125 of the first compressor 120.

[0080] As shown in FIG. 3, 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 second suction passage 135 to the second suction chamber 133a. The refrigerant further compressed by the second compressor 130 flows from the second compression chamber 133b through the second discharge passage 136, the communication hole 143a of the third closing plate 143, the discharge chamber 144, and the oil separation chamber 74 to the discharge port 75 of the rear head 70.

[0081] <Example 2> The electric compressor 250 of Example 2 will be described with reference to FIG. 9. FIG. 9 corresponds to FIG. 3 above.

[0082] The electric compressor 250 of Example 2 is characterized in that the two-stage compression mechanism 110 (multi-stage compression mechanism 110) of the electric compressor 50 of Example 1 shown in FIGS. 2 to 8 is changed to a twin compression mechanism 260 (parallel compression mechanism 260) shown in FIG. 9. For the electric compressor 250 and other configurations of the injection refrigeration cycle 10, 30 provided with this electric compressor 250, they are common to the electric compressor 50 of Example 1 and the injection refrigeration cycle 10, 30 provided with this electric compressor 50. For the parts common to the electric compressor 50 of Example 1 and the injection refrigeration cycle 10, 30 provided with this electric compressor 50, the reference numerals are reused and the detailed description is omitted.

[0083] Specifically, the electric compressor 250 includes a compression mechanism 260. This compression mechanism 260 is a configuration of a plurality of compressors including the first compressor 120 and the second compressor 130. This compression mechanism 260 is characterized in that in particular, two compressors 120, 130 are arranged in parallel for compression. This compression mechanism 260 may be referred to as the "twin compression mechanism 260" or the "parallel compression mechanism 260" as appropriate. The thickness of the cylinder 134 of the second compressor 130 may be the same as the thickness of the cylinder 124 of the first compressor 120.

[0084] This twin compression mechanism 260 is characterized in that it connects both the first suction passage 125 of the first compressor 120 and the second suction passage 135 of the second compressor 130 to the suction passage 86 of the partition block 80. More specifically, the second suction passage 135 of the second compressor 130 communicates 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 aggregated at the suction port 125a, and are directly connected to the suction passage 86 through this suction port 125a, so as to communicate with the motor chamber 61 through 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 does not communicate with the second suction passage 135 of the second compressor 130, but directly communicates with the discharge chamber 144 through the communication hole 271 of the rear head 70.

[0086] Next, the flow action of the refrigerant in the electric compressor 250 will be described. After cooling the motor 100, the refrigerant flowing into the suction passage 86 of the partition block 80 enters the first suction chamber 123a through the first suction passage 125 of the first compressor 120 and enters the second suction chamber 133a through the second suction passage 135 of the second compressor 130. 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] Summarizing the descriptions of the above Embodiment 1 and Embodiment 2, it is as follows.

[0088] As shown in FIGS. 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, and a partition block 80 that is located between the rear head 70 and the motor housing 60, partitions the intermediate chamber 71 and the motor chamber 61, and has a shaft through-hole 83 through which the drive shaft 105 can pass, and a bearing 106 (first bearing 106) that is fixed to the partition block 80 and rotatably supports the drive shaft 105. A closing plate 141 made of a member different 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 a high speed. The bearing 106 that supports the drive shaft 105 is required to be fitted into the fitting hole 84a (see FIG. 4) of the bearing fixing portion 84 without a gap. For this reason, the bearing 106 is fixed to the fitting hole 84a of the bearing fixing portion 84 by press-fitting (for example, shrink fitting). In that case, the partition block 80 may be deformed (distorted) due to the press-fitting. Further, the bearing 106 and the bearing fixing portion 84 receive a radial load associated with the load from the motor 100 and the compression mechanism 110; 260. In that case, the partition block 80 may be deformed (distorted) due to the radial load. 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. Consideration is required such that the deformation (distortion) generated by the bearing 104 does not affect the rotation of the rotating body 122 on this mating surface 82.

[0090] In contrast, in the present invention, a closing plate 141 made of a separate member is interposed between the partition block 80 and the compression mechanisms 110; 260. Thereby, the closing plate 141 blocks the transmission of deformation (strain) between the partition block 80 and the compression mechanisms 110; 260. Even if there is deformation (strain) of the partition block 80 generated by the bearing 106, the sliding surface 141c of the closing plate 141 on which the rotating body 122 (the first rotating body 122, the first piston 122) of the compression mechanisms 110; 260 slides can maintain a flat state as much as possible. As a result, the sliding surface 122a of the rotating body 122 can slide smoothly with respect to the sliding surface 141c of the closing plate 141, and the performance and durability of the compression mechanisms 110; 260 can be ensured.

[0091] As shown in FIGS. 4 and 9, the bearing 106 (the first bearing 106) is located on the side of the partition block 80 opposite to the compression mechanisms 110; 260 (the motor chamber 61 side). Thus, in the partition block 80, since the bearing 106 is arranged on the side opposite to the compression mechanisms 110; 260, it is possible to prevent the deformation due to the press-fitting of the bearing 106 and the radial load from being transmitted to the sliding surface 141c on which the rotating body 122 (the first rotating body 122, the first piston 122) of the compression mechanisms 110; 260 slides.

[0092] As shown in FIGS. 4 and 9, the compression mechanism 110; 260 (the first compressor 120) is a rolling piston type rotary compressor including a cylinder 124 (the first cylinder 124) that forms a cylinder chamber 123 (the first cylinder chamber 123) and a piston 122 (the first piston 122) that performs an eccentric rotational movement within the cylinder chamber 123. The piston 122 is positioned slidably with respect to the sliding surface 141c of the closing plate 141. Thus, since the piston 122 of the rolling piston type rotary compressor 120 slides with respect to the closing plate 141 instead of the partition block 80, it is not affected by the deformation due to the press-fitting of the bearing 106 and the radial load on the partition block 80.

[0093] As shown in FIGS. 3 and 9, the compression mechanisms 110; 260 are configured with a plurality of compressors including a first compressor 120 and a second compressor 130. Compared with the configuration of a single-stage compression mechanism (a single-cylinder mechanism), the compression ratios of the respective compressors 120, 130 can be reduced. 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 provided at symmetric positions with respect to the center line CL1 of the drive shaft 105.

[0094] Thus, since the compression mechanisms 110; 260 are configured with a plurality of compressors, the phases of rotation of the respective pistons 122, 132 are different, so the intake and compression timings occur alternately in each cylinder 123, 134. For example, when the first compression mechanism 120 performs an intake operation, the second compressor 130 performs a compression operation. The respective compressors 120, 130 cancel out the radial loads acting on the drive shaft 105 because the directions of the respective compression reaction forces are different. As a result, the radial load (support load) supported by the bearing 106 is significantly reduced. Since the radial load supported by the bearing 106 and the bearing fixing portion 84 is reduced, the deformation of the partition block 80 that supports this radial load can be reduced, and as a result, the transmission of the deformation from the partition block 80 to the sliding surface 141c of the first closing plate 141 can be further prevented. Therefore, the generation of vibration and noise of the electric compressor 50 can be suppressed, and the reliability of the electric compressors 50; 250 can be further enhanced.

[0095] As shown in FIGS. 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 communicates with the discharge chamber 144 via at least the discharge hole 141a provided in the closing plate 141 (first closing plate 141), the discharge valve 88 that opens and closes the discharge hole 141a, the discharge recess 87 provided in the partition block 80, and the intermediate chamber 71. By providing the discharge hole 141a of the first compressor 120 in the closing plate 141 in this way, the dead volume of the compression chamber 123b of the first compressor 120 can be reduced, which can contribute to the improvement of the performance of the compression mechanism 110.

[0096] As shown in FIGS. 4 and 9, the partition block 80 has a shaft seal holding hole 85 located on the concentric CL1 with respect to the shaft through hole 83. This shaft seal holding hole 85 opens on the side of the closing plate 141 in the partition block 80 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.

[0097] Thus, since the shaft through hole 83 and the drive shaft 105 are sealed by the shaft seal 108, it is possible to prevent the refrigerant present in the intermediate chamber 71 from leaking into the motor chamber 61 through the shaft through hole 83. Furthermore, since the closing plate 141 prevents the shaft seal 108 from moving in the axial direction of the drive shaft 105, wear of the shaft seal 108 can be further prevented.

[0098] As shown in FIGS. 4 and 9, the partition block 80 has a suction passage 86 that penetrates through 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 through which refrigerant can be suctioned. The suction port 125a is directly connected to the suction passage 86 and thus communicates with the motor chamber 61 via the suction passage 86.

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

[0100] Note that as long as the operation and effects of the present invention are achieved, the present invention is not limited to Embodiments 1 to 2. For example, the compression mechanism 110 may be configured as a multi-stage compression mechanism that compresses a plurality of compressors arranged in series. Also, the compression mechanism 260 may be configured as a parallel compression mechanism that compresses a plurality of compressors arranged in parallel. For example, in the refrigeration cycle, although Examples 1 to 2 were described using the injection type refrigeration cycle 10, a refrigeration cycle that does not introduce injection refrigerant gas may also be used.

Industrial Applicability

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

Explanation of Reference Numerals

[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 Axial through-hole 84 Bearing fixing portion 85 Shaft seal holding hole 86 Suction passage 87 Discharge recess (communication 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 Closing plate (first closing plate) 141a Discharge hole 141c Sliding surface 250 Electric compressor 260 Compression mechanism (twin compression mechanism) CL1 Center line

Claims

1. A compression mechanism (110; 260), a drive shaft (105) for driving the compression 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 compression 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, a bearing (106) fixed to the partition block (80) and rotatably supporting the drive shaft (105), An electric compressor (50; 250), characterized in that a closing plate (141) made of a member different from the partition block (80) is interposed between the partition block (80) and the compression mechanism (110; 260).

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 compression mechanism (110; 260).

3. 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 an eccentric rotational motion within the cylinder chamber (123), The electric compressor according to claim 1, wherein the piston (122) is positioned slidably with respect to a sliding surface (141c) of the closing plate (141).

4. The electric compressor according to claim 1, wherein the compression mechanism (110; 260) is configured with a plurality of compressors including a first compressor (120) and a second compressor (130).

5. The first compressor (120) is located closer to the partition block (80) than the second compressor (130), The compression chamber (123b) of the first compressor (120) communicates with the 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). The shaft seal holding hole (85) opens on the side of the closing plate (141) in the partition block (80), and holds a shaft seal (108) that seals between the shaft through hole (83) and the drive shaft (105). The electric compressor according to claim 1, wherein 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). **Claim 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) through which refrigerant can be inhaled. The electric compressor according to claim 1, wherein the suction port (125a) is directly connected to the suction passage (86) and communicates with the motor chamber (61) through the suction passage (86).

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