Electric compressor

Abstract

An electric compressor (50) comprises: a motor housing (60) including a motor chamber (6 1) that houses a motor (100); a rear head (70) including an intermediate pressure chamber (71) that houses a two-stage compression mechanism (110); and a dividing block (80) that is held between the motor housing (60) and the rear head (70), and partitions the motor c hamber (61) from the intermediate pressure chamber (71). The dividing block (80) includes : an injection inlet (151) through which an injection gas refrigerant can be introduced; an injection outlet (152) through which the injection gas refrigerant can be introduced to the i ntermediate pressure chamber (71); and an injection passage (153) that provides communica tion between the injection inlet (151) and the injection outlet (152).

Description

Technical Field

[0001] The present invention relates to technology for improving an electric compressor co mprising a compressing mechanism that performs two-stage compression of a refrigerant, an d a motor that drives the compressing mechanism.Background Art

[0002] Among electric compressors, there are rolling piston type rotary compressors that pe rform two-stage compression, have an intermediate pressure chamber around a compressing mechanism, and perform gas injection of intermediate-pressure refrigerant from an air condi tioning device circuit into the intermediate pressure chamber. For example, the technology of Patent Document 1 is known as such an electric compressor.

[0003] According to the technology known from Patent Document 1, a low-stage compress or is disposed below a motor inside a housing, and a high-stage compressor is disposed be low the low-stage compressor, resulting in what is known as a vertically-oriented electric c ompressor configuration. The interior of the housing is divided by a dividing member into a first hermetically sealed chamber that accommodates the motor and a second hermetically sealed chamber that accommodates the compressing mechanism.

[0004] An injection pipe for the intermediate-pressure refrigerant is provided in the housing and is connected to the second hermetically sealed chamber. The second hermetically seal ed chamber is thus configured to have an intermediate-pressure atmosphere. An intake pass age of the low-stage compressing mechanism communicates with the first hermetically seale d chamber. A discharge passage of the low-stage compressing mechanism opens into the se cond hermetically sealed chamber. An intake passage of the high-stage compressing mechan ism communicates with the second hermetically sealed chamber. A discharge passage of th e high-stage compression mechanism communicates with a discharge pipe for high-pressure refrigerant.Prior Art DocumentsPatent literature

[0005] Patent Document 1: JP 2000-054975 ASummary of the Invention Problems to be Solved by the Invention

[0006] Now, automotive air conditioning devices are exposed to vehicle vibrations and hig h refrigerant pressure due to high temperatures under blazing sun, and therefore have extre mely strict reliability requirements. As such, if the injection pipe is formed so as to penetr ate through the housing wall, the support for the injection pipe may become weak, and the re is a risk that an adequate reliability requirement may not be met.

[0007] The present invention has been devised in order to solve the above-mentioned probl ems, and an objective of the present invention is to provide technology that enables an inj ection pipe to be firmly supported by an electric compressor.Means for Solving the Problems

[0008] The reference symbols used in the appended drawings are added in parentheses in t he description below in order to make the present invention easier to understand, but this does not limit the present invention to the forms depicted.

[0009] According to the present invention, there is provided an electric compressor (50) in cluding a two-stage compressing mechanism (110) that has a low-stage compressor (120) a nd a high-stage compressor (130), a motor (100) that drives the two-stage compressing me chanism (110), a motor housing (60) that is provided with a motor chamber (61) for acco mmodating the motor (100), a rear head (70) that is provided with an intermediate pressur e chamber (71) for accommodating the two-stage compressing mechanism (110), and a divi ding block (80) that is sandwiched between the rear head (70) and the motor housing (60) and that divides the motor chamber (61) from the intermediate pressure chamber (71), char acterized in that the dividing block (80) is provided with an injection inlet (151) through which an injectio n gas refrigerant can be introduced, an injection outlet (152) through which the injection g as refrigerant can be led out to the intermediate pressure chamber (71), and an injection p assage (153) which provides communication between the injection inlet (151) and the inject ion outlet (152).

[0010] Preferably, a check valve (160) is disposed at the injection outlet (152) to allow th e injection gas refrigerant to flow only from the injection passage (153) to the intermediat e pressure chamber (71).

[0011] More preferably, the injection outlet (152) and the check valve (160) are provided on a flat surface (82) of the dividing block (80) that faces the intermediate pressure cham ber (71).

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

[0013] More preferably, the dividing block (80) has an intake passage (84), inside the divi ding block (80), that provides communication between the motor chamber (61) and an inta ke port (125a) of the low-stage compressor (120).

[0014] In another preferred example, the dividing block (80) is integrally provided with a shaft supporting portion (83) that supports a rotating shaft (101) of the two-stage compress ing mechanism (110).Effects of the Invention

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

[0016] [Fig. 1] Fig. 1A is a conceptual diagram showing an example of an injection type refrigeration cycle according to an exemplary embodiment, and fig. 1B is a conceptual dia gram showing another example of an injection type refrigeration cycle according to an exe mplary embodiment. [Fig. 2] is a cross-sectional view of the electric compressor shown in fig. 1. [Fig. 3] is an enlarged view around the two-stage compressing mechanism shown in fig. 2. [Fig. 4] is a cross-sectional view of the low-stage compressor shown in fig. 3 as seen fro m the axial direction of the motor spindle. [Fig. 5] is a cross-sectional view of the high-stage compressor shown in fig. 3 as seen fro m the axial direction of the motor spindle. [Fig. 6] is a cross-sectional view around the injection inlet in the dividing block shown in fig. 3. Embodiments of the Invention

[0017] Embodiments of the present invention will be described below with reference to the appended drawings. It should be noted that the forms depicted in the appended drawings are examples of the present invention, and the present invention is not limited to those for ms.<Exemplary embodiments>

[0018] An electric compressor 50 according to an exemplary embodiment, and injection-type refrig eration cycles 10 and 30 including the electric compressor 50 will be described with refere nce to fig. 1 to fig. 6.

[0019] Fig. 1A shows an example of an injection type refrigeration cycle 10 (hereinafter a bbreviated as "refrigeration cycle 10"). The refrigeration cycle 10 is used, for example, in an automotive air conditioning device, and performs space cooling and space heating by m eans of an interior air conditioning unit (not shown). It should be noted that there is no li mitation to the purpose of use of the refrigeration cycle 10. Furthermore, although the refri geration cycle 10 is suitable for use with R744 refrigerant, other refrigerants (for example, R134a refrigerant or R1234yf refrigerant) can also be used.

[0020] Here, injection type refers to a system in which the refrigeration cycle 10 causes hi gh-pressure refrigerant to expand in two stages, and returns intermediate-pressure gas refrig erant (gas phase refrigerant) obtained by gas-liquid separation to the electric compressor 50 . The intermediate-pressure gas refrigerant returned to the electric compressor 50 is called i njection gas refrigerant.

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

[0022] The electric compressor 50 includes a two-stage compressing mechanism 110. The t wo-stage compressing mechanism 110 has a low-stage compressor 120 and a high-stage co mpressor 130. In addition, the electric compressor 50 is provided with an intake port 68 c apable of drawing in the refrigerant from the outside (evaporator 11), a discharge port 75 capable of discharging the refrigerant to the outside (gas cooler 12), and an injection inlet 151 through which the injection gas refrigerant can be introduced.

[0023] A refrigerant outlet of the gas cooler 12 is connected to a refrigerant inlet of the g as-liquid separator 15 by a first flow passage 21, via the first expansion valve 13. A refri gerant outlet of the gas-liquid separator 15 is connected to an injection pipe 22 through w hich the injection gas refrigerant flows, and to a second flow passage 23 through which th e liquid refrigerant flows. The injection pipe 22 is connected to the injection inlet 151 of the electric compressor 50.

[0024] The second flow passage 23 is connected to a refrigerant inlet of the evaporator 11 via a second expansion valve 14. A refrigerant outlet of the evaporator 11 is connected t o the intake port 68 of the electric compressor 50 by a third flow passage 24. The discha rge port 75 of the electric compressor 50 is connected to a refrigerant inlet of the gas coo ler 12 by a fourth flow passage 25.

[0025] The refrigerant flows in the direction indicated by the solid lines in fig. 1A. That i s, refrigerant that has been subjected to heat exchange with outside air by the gas cooler 12 flows through the first flow passage 21, the first expansion valve 13, the gas-liquid sep arator 15, the second expansion valve 14, and the evaporator 11 to the intake port 68 of t he electric compressor 50, and is compressed to a high pressure. The refrigerant that has b een compressed to a high pressure by the electric compressor 50 flows to the gas cooler 1 2 through the fourth flow passage 25.

[0026] In this way, the refrigerant that has been subjected to heat exchange with outside a ir by the gas cooler 12 is subjected to rapid adiabatic expansion by the first expansion val ve 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 ex pansion valve 13 and the second expansion valve 14.

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

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

[0029] In this other example of the refrigeration cycle 30, the refrigerant branched from th e portion 21a between the gas cooler 12 and the internal heat exchanger 31, i.e., from the branch point 21a, is subjected to adiabatic expansion by the first expansion valve 13 and i s then heated by the internal heat exchanger 31, and the heated gas refrigerant flows throu gh the injection pipe 22 to the injection inlet 151 of the electric compressor 50.

[0030] The overall configuration of the electric compressor 50 will next be described. As shown in fig. 2, the electric compressor 50 has what is known as a horizontally-oriente d electric compressor configuration in which the two-stage compressing mechanism 110 is disposed beside the motor 100, for example. The electric compressor 50 includes the housi ng 51, the motor 100, and the two-stage compressing mechanism 110, which is driven by the motor 100.

[0031] The housing 51 is configured to be capable of being installed horizontally. The hou sing 51 includes a motor housing 60 provided with a motor chamber 61 for accommodatin g the motor 100, a rear head 70 provided with an intermediate pressure chamber 71 for ac commodating the two-stage compressing mechanism 110, and a dividing block 80 sandwich ed between the motor housing 60 and the rear head 70. The motor housing 60, the rear h ead 70, and the dividing block 80 are made of castings of a metal material such as alumi num (including aluminum alloys).

[0032] The motor housing 60 is a bottomed cylindrical member. One end of the motor ho using 60 in the axial direction is closed by a bottom wall 62. The bottom wall 62 is form ed integrally with the motor housing 60, for example. The other end of the motor housing 60 in the axial direction is completely open. An open end surface 63 of the motor housin g 60 may be referred to as a first end surface 63. The first end surface 63 is a flat surfa ce that is perpendicular to an axial direction center line CL1 of the motor housing 60. Th e motor chamber 61 is formed inside the motor housing 60. An inverter housing 65 is ass embled to an outer wall surface 62a of the bottom wall 62 of the motor housing 60. An i nverter device 66 for supplying driving electric power to the motor 100 is accommodated i n the inverter housing 65.

[0033] The motor housing 60 additionally includes an intake port 68 through which refrige rant is drawn into the motor chamber 61 from the outside. More specifically, a boss portio n 69 that protrudes radially outward is provided on an outer peripheral surface 60a of the motor housing 60. The intake port 68 opens in the boss portion 69. The third flow passag e 24 (refrigerant supply pipe 24) shown in fig. 1 is connected to the intake port 68.

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

[0035] The rear head 70 additionally includes an oil separation chamber 74 for separating oil from the refrigerant compressed by the two-stage compressing mechanism 110, and a di scharge port 75 for discharging, to the outside, gaseous refrigerant from which the oil has been separated by the oil separation chamber 74. The discharge port 75 is connected to th e fourth flow passage 25 (refrigerant discharge pipe 25) shown in fig. 1.

[0036] The dividing block 80 is a disk-shaped member that divides the motor chamber 61 from the intermediate pressure chamber 71, and is sandwiched between the first end surfac e 63 of the motor housing 60 and the second end surface 73 of the rear head 70. More s pecifically, as shown in fig. 3, the dividing block 80 has a first mating surface 81 facing the first end face 63 of the motor housing 60 and the motor chamber 61, and a second m ating surface 82 facing the second end face 73 of the rear head 70 and the intermediate p ressure chamber 71. The first mating surface 81 and the second mating surface 82 are flat surfaces that are perpendicular to the axial direction center line CL1 of the motor housing 60. The first mating surface 81 and the second mating surface 82 may be referred to as t he "first flat surface 81 and the second flat surface 82" as appropriate.

[0037] Gaps between the first end surface 63 of the motor housing 60 and the first matin g surface 81 of the dividing block 80, and between the second end surface 73 of the rear head 70 and the second mating surface 82 of the dividing block 80 are each sealed by a sealing member (not shown) such as a gasket or an O-ring. The dividing block 80 is restri cted in terms of both relative rotation and relative axial movement with respect to the mot or housing 60 and the rear head 70. For example, the dividing block 80 is fixed integrally together with the motor housing 60 and the rear head 70 by means of fastening members 91 such as bolts.

[0038] The motor 100 will be described next. As shown in fig. 2, the motor 100 includes an output shaft 101 (motor spindle 101), a rot or 102 fixed to the output shaft 101, and a cylindrical stator 103 surrounding the peripher y of the rotor 102.

[0039] The output shaft 101 has its center of rotation at the axial direction center line CL 1 of the motor housing 60, extends from the motor chamber 61 toward the intermediate pr essure chamber 71, penetrates through the dividing block 80, and is drivably coupled to th e two-stage compressing mechanism 110. In other words, the output shaft 101 of the moto r 100 also serves as the rotating shaft 101 of the two-stage compressing mechanism 110. Hereinafter, the output shaft 101 of the motor 100 may alternatively be referred to as the "rotating shaft 101 of the two-stage compressing mechanism 110" as appropriate. The outp ut shaft 101 (rotating shaft 101) is rotatably supported by a first bearing 104 provided in t he dividing block 80 and a second bearing 105 provided in the bottom wall 62 of the mot or housing 60.

[0040] As shown in fig. 3, the dividing block 80 is formed integrally with a shaft support ing portion 83 in which to install the first bearing 104. That is, the dividing block 80 is provided integrally with the shaft supporting portion 83, which supports the rotating shaft 101 of the two-stage compressing mechanism 110. The shaft supporting portion 83 protrude s from the first mating surface 81 of the dividing block 80 toward the motor chamber 61. It should be noted that the shaft supporting portion 83 includes a configuration that directl y supports the rotating shaft 101 without the first bearing 104 interposed therebetween.

[0041] The axial direction center line CL1 of the motor housing 60 may alternatively be r eferred to as the "center line CL1 of the output shaft 101 (rotating shaft 101)." It should be noted that the output shaft 101 of the motor 100 may equally be configured as a separ ate member from the output shaft of the two-stage compressing mechanism 110. In this ca se, the output shaft 101 of the motor 100 is configured with a linking member such as a coupling that is coupled to the output shaft of the two-stage compressing mechanism 110.

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

[0043] The two-stage compressing mechanism 110 will next be described. As shown in fig. 3, the low-stage compressor 120 and the high-stage compressor 130 cons tituting the two-stage compressing mechanism 110 are both configured as what is known a s rolling piston type rotary compressor that perform compression using rotating bodies 122, 132 (pistons 132, 132) that perform a rotating motion, and cylinders 124, 134. The low-st age compressor 120 and the high-stage compressor 130 have substantially the same configu ration, and are aligned on the center line CL1 of the rotating shaft 101 (output shaft 101). The low-stage compressor 120 is located on the dividing block 80 side of the intermediat e pressure chamber 71. The high-stage compressor 130 is located in the intermediate press ure chamber 71 on the bottom wall 72 side of the rear head 70.

[0044] More specifically, as shown in fig. 3 and fig. 4, the low-stage compressor 120 incl udes a first eccentric shaft 121 provided integrally with the rotating shaft 101, an annular first piston 122 (first rotating body 122) fitted onto the first eccentric shaft 121, and a flat plate-shaped first cylinder 124 having a first cylinder chamber 123 that permits the rotatin g motion of the first piston 122. A center line CL2 of the first eccentric shaft 121 is offs et from the center line CL1 of the rotating shaft 101.

[0045] The first cylinder 124 is restricted from rotating relative to the rear head 70. The f irst cylinder 124 has a first surface 124a facing the second mating surface 82 of the divid ing block 80 and a second surface 124b facing the second cylinder 134 of the high-stage compressor 130. The first surface 124a and the second surface 124b of the first cylinder 1 24 are flat surfaces that are perpendicular to the axial direction center line CL1 of the mo tor housing 60.

[0046] The first cylinder chamber 123 is a circular hole that is concentric with the center line CL1 of the rotary shaft 101, and that penetrates through the first cylinder 124. The fi rst cylinder 124 additionally includes a first intake passage 125 and a first discharge passa ge 126 that communicate with the first cylinder chamber 123. The first intake passage 125 and the first discharge passage 126 open at a first surface 124a of the first cylinder 124.

[0047] The outer diameter of the first piston 122 is smaller than the inner diameter of the first cylinder chamber 123. A first vane 127 in the shape of a vertical plate is in contact with an outer circumferential surface of the first piston 122 so as to be capable of moving forward and backward. The first vane 127 partitions the first cylinder chamber 123 into a n intake chamber and a compression chamber. The tip of the first vane 127 is pressed aga inst the outer circumferential surface of the first piston 122 by a first spring 128. The firs t piston 122 revolves around the inside of the first cylinder chamber 123. The refrigerant i ntroduced into the first cylinder chamber 123 from the first intake passage 125 is compres sed through the revolving motion of the first piston 122 and is discharged from the first d ischarge passage 126.

[0048] As shown in fig. 3 and fig. 5, similarly to the low-stage compressor 120, the high-stage compressor 130 includes a second eccentric shaft 131 provided integrally with the rot ating shaft 101, an annular second piston 132 (second rotating body 132) fitted onto the s econd eccentric shaft 131, and a flat plate-shaped second cylinder 134 having a second cyl inder chamber 133 that permits the rotating motion of the second piston 132. A center lin e CL3 of the second eccentric shaft 131 is offset from the center line CL1 of the rotating shaft 101.

[0049] The second cylinder 134 is restricted from rotating relative to the rear head 70. Th e second cylinder 134 additionally 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 ar e flat surfaces that are perpendicular to the axial direction center line CL1 of the motor h ousing 60.

[0050] The second cylinder chamber 133 is a circular hole that is concentric with the cent er line CL1 of the rotary shaft 101, and that penetrates through the second cylinder 134. The second cylinder 134 additionally includes a second intake passage 135 and a second d ischarge passage 136 that communicate with the second cylinder chamber 133. The second intake passage 135 opens at the outer circumferential surface of the second cylinder 134, t hereby providing communication between the second cylinder chamber 133 and the interme diate pressure chamber 71. The second discharge passage 136 opens at the second surface 134b of the second cylinder 134.

[0051] The outer diameter of the second piston 132 is smaller than the inner diameter of t he second cylinder chamber 133. A second vane 137 in the shape of a vertical plate is in contact with an outer circumferential surface of the second piston 132 so as to be capable of moving forward and backward. The second vane 137 partitions the second cylinder cha mber 133 into an intake chamber and a compression chamber. The tip of the second vane 137 is pressed against the outer circumferential surface of the second piston 132 by a seco nd spring 138. The second piston 132 revolves around the inside of the second cylinder ch amber 133. The refrigerant introduced into the second cylinder chamber 133 from the seco nd intake passage 135 is compressed through the revolving motion of the second piston 13 2 and is discharged from the second discharge passage 136.

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

[0053] As shown in fig. 3, the first cylinder chamber 123 is closed on the dividing block 80 side by a flat plate-shaped first closing plate 141. The first closing plate 141 is sandwi ched between the second mating surface 82 of the dividing block 80 and the first surface 124a of the first cylinder 124.

[0054] Furthermore, the first closing plate 141 has a first through-hole 141a that communic ates with an intake port 125a of the first intake passage 125, and a second through-hole 1 41b that communicates with the first discharge passage 126. The first through-hole 141a an d the second through-hole 141b penetrate through the first closing plate 141 in the thickne ss direction.

[0055] The intake port 125a of the first intake passage 125 communicates with an intake passage 84 of the dividing block 80 through the first through-hole 141a of the first closin g plate 141. The intake passage 84 penetrates through the dividing block 80 in the axial d irection of the motor housing 60. That is, the intake passage 84 is located inside the divid ing block 80. Therefore, the first cylinder chamber 123 communicates with the intake port 68 (see fig. 2) of the motor housing 60 via the first intake passage 125, the first through-hole 141a of the first closing plate 141, the intake passage 84 of the dividing block 80, a nd the motor chamber 61.

[0056] The dividing block 80 has a communication groove 85 that provides communication between the second through-hole 141b of the first closing plate 141 and the intermediate pressure chamber 71. The communication groove 85 is formed in the second mating surfac e 82 of the dividing block 80. A discharge valve 86 that opens and closes the opening of the second through-hole 141b is provided within the communication groove 85. The dischar ge valve 86 is configured by a check valve, such as a reed valve, that allows the injectio n gas refrigerant to flow only from the first discharge passage 126 to the communication groove 85. The first cylinder chamber 123 communicates with the second cylinder chamber 133 via the first discharge passage 126, the second through-hole 141b, the communication groove 85, the intermediate pressure chamber 71, and the second intake passage 135.

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

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

[0059] The first cylinder 124, the second cylinder 134, the first closing plate 141, the sec ond closing plate 142, and the third closing plate 143 are sandwiched in the axial directio n of the rear head 70 between the stepped surface 76 of the rear head 70 and the dividin g block 80.

[0060] A discharge chamber 144 demarcated by the bottom wall 72 and the third closing plate 143 is formed inside the rear head 70. The third closing plate 143 has a communicat ing hole 143a that provides communication between the second discharge passage 136 of t he second cylinder 134 and the discharge chamber 144. A discharge valve 145 that opens and closes the opening of the through-hole 143a is provided within the discharge chamber 144. The discharge valve 145 is configured by a check valve, such as a reed valve, that a llows the injection gas refrigerant to flow only from the second discharge passage 136 to t he discharge chamber 144. The discharge chamber 144 communicates with the oil separatio n chamber 74. The refrigerant in the high-stage compressor 130 can flow into the oil sepa ration chamber 74 through the second discharge passage 136, the communicating hole 143a and the discharge chamber 144. It should be noted that the tip end portion of the rotatin g shaft 101 is preferably rotatably supported by a third bearing 146 provided in the third closing plate 143.

[0061] As shown in fig. 6, the dividing block 80 includes the injection inlet 151, an inject ion outlet 152, and an injection passage 153. The injection passage 153 provides communi cation between the injection inlet 151 and the injection outlet 152. At least the injection o utlet 152 and the injection passage 153 are disposed within the dividing block 80.

[0062] The injection inlet 151 is formed integrally with the dividing block 80, for example . More specifically, a boss portion 154 that protrudes radially outward is provided on an o uter peripheral surface 87 of the dividing block 80. The injection inlet 151 opens in the b oss portion 154. The injection pipe 22 (see fig. 1) is connected to the injection inlet 151 t o allow the injection gas refrigerant to be introduced.

[0063] The injection outlet 152 opens at the second mating surface 82 (second flat surface 82) of the dividing block 80 that faces the intermediate pressure chamber 71, thereby com municating with the intermediate pressure chamber 71. The injection outlet 152 can therefo re guide the injection gas refrigerant out to the intermediate pressure chamber 71.

[0064] The injection outlet 152 is provided with a check valve 160. The check valve 160 allows the injection gas refrigerant to flow only from the injection passage 153 to the inte rmediate pressure chamber 71. That is, when the pressure in the injection passage 153 incr eases above the pressure in the intermediate pressure chamber 71, the pressure difference c auses the check valve 160 to open.

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

[0066] The flow action of refrigerant within the electric compressor 50 will next be descri bed. As shown in fig. 2, the refrigerant drawn in from the intake port 68 of the motor ho using 60 passes through gaps in the motor 100 installed in the motor chamber 61, thereby cooling the motor 100, and then flows into the intake passage 84 of the dividing block 80 . The refrigerant that has passed through the intake passage 84 passes through the first thr ough-hole 141a of the first closing plate 141 and the first intake passage 125 of the low-s tage side compressor 120 and enters the first cylinder chamber 123.

[0067] As shown in fig. 3, the refrigerant compressed by the low-stage compressor 120 flo ws from the first cylinder chamber 123 through the first discharge passage 126, the second through-hole 141b of the first closing plate 141, the communication groove 85 of the divi ding block 80, the intermediate pressure chamber 71, and the second intake passage 135 to the second cylinder chamber 133. The refrigerant that has been further compressed by the high-stage compressor 130 flows from the second cylinder chamber 133 through the secon d discharge passage 136, the communication hole 143a of the third closing plate 143, the discharge chamber 144, and the oil separation chamber 74 to the discharge port 75 of the rear head 70.

[0068] A summary of the description above is as follows.

[0069] As shown in fig. 2, an electric compressor 50 includes a two-stage compressing me chanism 110 that has a low-stage compressor 120 and a high-stage compressor 130, a mot or 100 that drives the two-stage compressing mechanism 110, a motor housing 60that is pr ovided with a motor chamber 61 for accommodating the motor 100, a rear head 70that is provided with an intermediate pressure chamber 71 for accommodating the two-stage compr essing mechanism 110, and a dividing block 80 that is sandwiched between the rear head 70 and the motor housing 60 and that divides the motor chamber 61 from the intermediate pressure chamber 71.

[0070] As shown in fig. 6, the dividing block 80 is provided with an injection inlet 151 t hrough which an injection gas refrigerant can be introduced, an injection outlet 152 throug h which the injection gas refrigerant can be led out to the intermediate pressure chamber 7 1, and an injection passage 153 which provides communication between the injection inlet 151 and the injection outlet 152. In this way, the dividing block 80 is sandwiched between the motor housing 60 and the r ear head 70, and is therefore extremely robust. The injection inlet 151, the injection outlet 152, and the injection passage 153 are provided in the robust dividing block 80. The injec tion pipe 22 can therefore be firmly supported by the electric compressor 50.

[0071] As shown in fig. 6, a check valve 160 is disposed at the injection outlet 152 to al low the injection gas refrigerant to flow only from the injection passage 153 to the interm ediate pressure chamber 71. It is therefore possible to prevent the refrigerant from flowing back from the intermediate pressure chamber 71 toward the injection inlet 151 side. As a result, the efficiency of the injection type refrigeration cycle 10, 30 (see fig. 1A and fig. 1B) can be improved.

[0072] As shown in fig. 6, the injection outlet 152 and the check valve 160 are provided at the flat surface 82 (second flat surface 82, second mating surface 82) of the dividing bl ock 80 that faces the intermediate pressure chamber 71. By providing the check valve 160 on the flat surface 82 of the dividing block 80 in this way, the configuration and attachm ent structure of the check valve 160 can be simplified.

[0073] As shown in fig. 6, the check valve 160 is configured by a reed valve 161. The c heck valve 160 is configured by assembling the reed valve 161 to the flat surface 82 (sec ond flat surface 82, second mating surface 82) of the dividing block 80 that faces the inte rmediate pressure chamber 71, and can therefore have a simple configuration. As shown in fig. 3, the dividing block 80 has an intake passage 84, inside the dividing bl ock 80, that provides communication between the motor chamber 61 and the intake port 1 25a of the low-stage compressor 120.

[0074] In this way, the intake passage 84 providing communication between the motor cha mber 61 and the intake port 125a of the low-stage compressor 120, and the injection inlet 151, injection outlet 152, and injection passage 153 are provided inside the dividing block 80. In other words, the intake passage 84, the injection inlet 151, the injection outlet 152, and the injection passage 153 can all be consolidated into the dividing block 80 alone, the reby making it possible to simplify the configuration of the electric compressor 50.

[0075] As shown in fig. 3, the dividing block 80 is provided integrally with a shaft suppo rting portion 83 which supports the rotating shaft 101 of the two-stage compressing mecha nism 110. As a result, the dividing block 80 that divides the motor chamber 61 from the intermediate pressure chamber 71 can be utilized to support the rotating shaft 101 of the t wo-stage compressing mechanism 110. It is not necessary to provide a separate member fo r supporting the rotating shaft 101. The configuration of the electric compressor 50 can be simplified. In addition, since the rotating shaft 101 is supported by the dividing block 80 t hat is sandwiched between the motor housing 60 and the rear head 70, the overall electric compressor 50 becomes robust. The shaft supporting portion 83 can support the rotating sh aft 101 directly or via a bearing 104 or a plain bearing.

[0076] It should be noted that the present invention is not limited to the exemplary embod iments, provided that the actions and effects of the present invention are demonstrated. For example, the electric compressor 50 is not limited to a horizontally-oriented electric co mpressor, and may equally be a vertically-oriented electric compressor.Industrial Applicability

[0077] The electric compressor 50 of the present invention is suitable for use in the injecti on type refrigeration cycles 10 and 30.Key to Symbols

[0078] 10, 30Injection type refrigeration cycle 50Electric compressor 60Motor housing 61Motor chamber 68Intake port 70Rear head (compressor housing) 71Intermediate pressure chamber 75Discharge port 80Dividing block 82Flat surface (second mating surface, second flat surface) 83Shaft supporting portion 84Intake passage 85Communication groove 100Motor 101Rotating shaft (output shaft) 110Two-stage compressing mechanism 120Low-stage compressor 125First intake passage 125aIntake port 130High-stage compressor 135Second intake passage 136Second discharge passage 151Injection inlet 152Injection outlet 153Injection passage 160Check valve 161Reed valve

Claims

1. An electric compressor (50) including a two-stage compressing mechanism (110) that has a low-stage compressor (120) and a high-stage compressor (130), a motor (100) that drives the two-stage compressing mechanism (110), a motor housing (60) that is provided with a motor chamber (61) for accommodating the motor (100), a rear head (70) that is provided with an intermediate pressure chamber (71) for accommo dating the two-stage compressing mechanism (110), and a dividing block (80) that is sandwiched between the rear head (70) and the motor housin g (60) and that divides the motor chamber (61) from the intermediate pressure chamber (7 1), characterized in that the dividing block (80) is provided with an injection inlet (151) through which an injection gas refrigerant can be introduced, an injection outlet (152) through which the injection gas refrigerant can be led out to the intermediate pressure chamber (71), and an injection passage (153) which provides communication between the injection inlet (151) and the injection outlet (152).

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

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

4. The electric compressor as claimed in claim 3, wherein the check valve (160) is configured by a reed valve (161).

5. The electric compressor as claimed in any one of claims 1 to 4, wherein the di viding block (80) has an intake passage (84), inside the dividing block (80), that provides communication between the motor chamber (61) and an intake port (125a) of the low-stage compressor (120).

6. The electric compressor as claimed in claim 1, wherein the dividing block (80) is integrally provided with a shaft supporting portion (83) that supports a rotating shaft (10 1) of the two-stage compressing mechanism (110).

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