JP2004060605A - Electric compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric compressor capable of increasing the efficiency of a refrigerating cycle system while minimizing an increase in weight for securing a pressure resistance even in those compressors used under a high pressure with CO<SB>2</SB>as a refrigerant. <P>SOLUTION: In this electric compressor, CO<SB>2</SB>is used as a working fluid, and the sucked working fluid is compressed by a compressor part 130 after being passed through a motor part 120. The electric compressor comprises a lubricating oil separator 150 separating the lubricating oil included in the working fluid on the delivery side of the compressor part 130, an oil storage chamber 160 storing the separated lubricating oil, and a circulating passage 170 depressurizing and circulating the lubricating oil stored in the oil storage chamber 160 to the low pressure side of the compressor part 130. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric compressor applied to a refrigeration cycle device using CO ₂ as a refrigerant.
[0002]
[Prior art]
As a technique related to a conventional electric compressor, there is known a so-called suction cooling system in which a motor chamber is set to a low-pressure atmosphere and a motor is cooled by a suction refrigerant, as disclosed in JP-A-2001-12352.
[0003]
In this electric compressor, for example, even when CO ₂ is used as a refrigerant under a high pressure exceeding the critical pressure, the thickness of the housing forming the motor chamber is kept to a minimum because the low pressure atmosphere is used. It is possible and effective for weight reduction.
[0004]
[Problems to be solved by the invention]
However, in the suction cooling system, the motor chamber cannot be used as a separation chamber for oil contained in the discharged refrigerant, so lubrication of the compressor requires lubrication with return oil by circulation in the refrigeration cycle system to lubricate the compressor. And the oil rate in the system could not be reduced. When the oil rate in the system is high, the heat exchange efficiency of the heat exchanger is reduced, the volume efficiency of the compressor itself is reduced, and the like, and the efficiency of the system is reduced.
[0005]
In view of the above problems, an object of the present invention is to make it possible to improve the efficiency of a refrigeration cycle system while minimizing an increase in weight for ensuring pressure resistance, even when CO ₂ is used as a refrigerant under high pressure. The present invention provides an electric compressor.
[0006]
[Means for Solving the Problems]
The present invention employs the following technical means to achieve the above object.
[0007]
According to the first aspect of the present invention, in the electric compressor in which CO ₂ is used as a working fluid, and the sucked working fluid flows through the motor unit (120), the compressor is compressed by the compressor unit (130). A lubricating oil separator (150) for separating the lubricating oil contained in the working fluid on the discharge side of (130), an oil storage chamber (160) for storing the separated lubricating oil, and an oil storage chamber (160). A recirculation passage (170) for reducing pressure and returning the lubricating oil to the low pressure side of the compressor section (130) is provided.
[0008]
Accordingly, the motor section (120) does not need to have a strength capable of withstanding high pressure after the working fluid is compressed, and the thickness of the housing (112) can be reduced, so that the weight of the electric compressor (100) increases. Can be suppressed. In particular, in the electric compressor (100) used under a high pressure exceeding the critical pressure using CO ₂ as a working fluid, the weight becomes extremely large from the beginning to secure the pressure resistance, but the pressure resistance described above is unnecessary. A large weight reduction effect can be obtained.
[0009]
Further, since the lubricating oil in the working fluid is separated on the discharge side and returned to the low-pressure side of the compressor unit (130) again, the lubrication of the compressor unit (130) can be provided, so that the oil in the working fluid can be provided. By reducing the rate, it is possible to suppress a decrease in the efficiency of the heat exchanger and the compressor section (130) itself, and to improve the system efficiency of the refrigeration cycle apparatus.
[0010]
As the lubricating oil separator (150), a centrifugal separator is suitable as in the invention described in claim 2, and can be easily coped with an inexpensive structure.
[0011]
By the way, in the case where the working fluid is handled under a high pressure such as CO ₂ , it is very difficult to reduce the lubricating oil by a predetermined amount as the throttle portion (171) of the return passage (170) in order to return a predetermined amount of lubricating oil. Although a hole having a small diameter is required and the processing becomes more difficult, the throttle portion (171) for reducing the pressure in the return passage (170) is provided with a return passage (170) as in the invention according to claim 3. Is a gap (171) formed by opening into a gap between members (135, 140) in the compressor section (130), the throttle section (171) can be easily formed.
[0012]
According to the fourth aspect of the present invention, the member (135) on the side facing the opening (172) of the reflux passage (170) is a movable member (135) in the compressor section (130). Features.
[0013]
Thereby, the minute foreign matter contained in the lubricating oil easily flows together with the lubricating oil along with the movement of the movable member (135), so that the stagnation occurs near the opening (172) and the opening (172) is closed. Can be prevented.
[0014]
It is preferable that the compressor section (130) be a scroll type compressor section (130) and the movable member (135) be applied as a movable scroll (135).
[0015]
In the invention described in claim 6, the outer shell (113) of the compressor section (135) is formed as a housing (113) that receives a low pressure side pressure, and the second housing (161) included in the housing (113). ) To form an oil storage chamber (160).
[0016]
Thus, the housing (113) of the compressor section (130) may be capable of withstanding the pressure of the difference between the low pressure side pressure and the atmospheric pressure similarly to the motor section (120), and may be directly connected to the atmosphere. The safety factor against leakage of the working fluid can be increased. In addition, the thickness of the housing (113) can be unified with the motor (120) side to standardize the housing material.
[0017]
Further, since the second housing (161) receives a pressure difference between the high-pressure side pressure and the low-pressure side pressure, the thickness of the second housing (161) is reduced as compared with the case where the second housing (161) receives the high-pressure side pressure at atmospheric pressure. Can respond.
[0018]
Note that the reference numerals in parentheses of the above means indicate the correspondence with specific means described in the embodiment described later.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
A first embodiment of the present invention will be described with reference to FIGS. The electric compressor 100 is applied to a refrigeration cycle device (not shown) using CO ₂ as a refrigerant (working fluid), and a compressor unit 130 is operated by a motor unit 120 incorporated therein. And
[0020]
The motor section 120 and the compressor section 130 are housed in a housing 110 as a sealed container formed by welding a front housing 111, a middle housing 112, and an end housing 113 to each other. The front housing 111 is provided with a suction port 111a through which the refrigerant is sucked.
[0021]
A support plate 114 and a frame 115 to which bearings 132 and 133 are fixed are provided on the front housing 111 side and the intermediate portion in the middle housing 112, respectively, and the drive shaft 131 is rotatably supported by the bearings 132 and 133. Have been.
[0022]
The motor section 120 includes a rotor section 121 and a stator section 122 housed in a motor chamber 123 formed in the middle housing 112. The rotor part 121 is fixed to the drive shaft 131, and the stator part 122 is fixed to the inner peripheral surface of the middle housing 112 on the outer peripheral side of the rotor part 121 by press fitting. When power from an external power supply (not shown) is supplied to the stator unit 122, the drive shaft 131 is driven to rotate with the rotation of the rotor unit 121. The support plate 114 is provided with a flow passage 114a through which the refrigerant sucked from the suction port 111a flows into the motor chamber 123.
[0023]
The compressor section 130 forms a well-known scroll compressor having a movable scroll 135 and a fixed scroll 136 as internal members. The fixed scroll 136 is fixed to the side opposite to the motor portion in the middle housing 112, and a movable scroll 135 as a movable member is provided so as to mesh with the fixed scroll 136.
[0024]
An eccentric portion 131 a provided at the tip of the drive shaft 131 is inserted into the movable scroll 135 on the side opposite to the fixed scroll via a bearing 134. Then, the orbiting scroll 135 revolves with respect to the fixed scroll 136 by rotation of the drive shaft 131 by a rotation preventing mechanism (not shown).
[0025]
A suction chamber 141 is formed on the outer peripheral side between the scrolls 135 and 136, and a compression chamber 142 is formed toward the center. The frame 115 has a flow passage 115 a through which the refrigerant flowing into the motor chamber 123 flows through the suction chamber 141.
[0026]
In the fixed scroll 136, a discharge port 136a through which the refrigerant compressed in the compression chamber 142 is discharged and a discharge chamber 143 are formed. The discharge port 136 a is formed as a hole provided in the center of the fixed scroll 136, and the discharge chamber 143 is formed as a space in which a concave portion provided in the fixed scroll 136 is partitioned by a partition plate 137.
[0027]
An oil separator 150, an oil storage chamber 160, and a return passage 170, which are characteristic parts of the present invention, are provided while the compressed refrigerant is discharged from the discharge chamber 112 to the discharge port 112 a through the flow passage 136 b. .
[0028]
The oil separator 150 is a centrifugal-type lubricating oil separator that separates the lubricating oil contained in the refrigerant on the discharge side of the compressor unit 130, and includes a separation pipe 151, a separation cylinder 152, an introduction passage 153, and a discharge hole 154. Become.
[0029]
The separation pipe 151 is a pipe member having an outer diameter set in two stages. The separation cylinder 152 is a cylindrical space formed by the biconcave portions provided on the fixed scroll 136 and the partition plate 137.
[0030]
The large-diameter side of the separation pipe 151 is press-fitted and fixed above the separation tube 152, and the small-diameter side of the separation pipe 151 extends downward in the separation tube 152. The separation pipe 151 is in communication with the flow passage 136b and the discharge port 112a.
[0031]
As shown in FIG. 2, an introduction passage 153 is provided in the separation tube 152 so as to be in contact with the inner peripheral surface of the separation tube 152 so that the discharge chamber 143 and the inside of the separation tube 152 are communicated with each other. Further, a discharge hole 154 communicating with an oil storage chamber 160 formed between the end housing 113 as an oil storage chamber cover and the partition plate 137 is provided below the separation cylinder 152.
[0032]
The oil storage chamber 160 stores the lubricating oil in the refrigerant separated by the oil separator 150. In the oil storage chamber 160, the discharge pressure (high pressure side pressure) of the refrigerant is added from the discharge chamber 143 via the introduction passage 153, the separation cylinder 152, and the discharge hole 154, so that the plate pressure t2 of the end housing 113 before compression is reduced. The thickness is set to be thicker than the plate pressure t1 of the front and middle housings 111 and 112 to which the refrigerant pressure (low pressure side pressure) is applied.
[0033]
The return passage 170 is for reducing the pressure of the lubricating oil stored in the oil storage chamber 160 to the low-pressure side of the compressor section 130 and returning the lubricating oil, and includes an oil supply passage 170a and an oil supply pipe 170b. The refueling passage 170a is provided near the suction chamber 141 of the fixed scroll 136. As shown in FIG. 3, the oil supply passage 170 a faces the orbiting scroll 135, forms an opening 172 in a gap δ generated between the scrolls 135 and 136 by a thrust force during operation, and communicates with the suction chamber 141. I have. The oil supply passage 170a is connected to an oil supply pipe 170b so as to communicate with the vicinity of the lower side of the oil storage chamber 160.
[0034]
Then, as shown in FIG. 4, a gap (area πdδ) on the side surface of the virtual flat cylinder formed by the gap δ and the inner diameter φd of the oil supply passage 170 a is used to reduce the pressure from the oil storage chamber 160 to the suction chamber 141. The aperture unit 171 is provided.
[0035]
Next, operations and effects based on the above configuration will be described. In the electric compressor 100, the movable scroll 135 is revolved by the driving of the motor unit 120, and the refrigerant flowing into the suction chamber 141 via the suction port 111 a, the flow path 114 a, the motor chamber 123, and the flow path 115 a is compressed in the compression chamber 142. . At this time, the refrigerant circulates through the motor unit 120, so that the motor unit 120 is cooled. When the refrigerant compressed in the compression chamber 142 reaches a predetermined discharge pressure, the refrigerant is discharged from the discharge port 136a to the discharge chamber 143.
[0036]
Further, the refrigerant flows from the discharge chamber 143 into the separation tube 152 through the introduction passage 153 of the oil separator 150. At this time, the refrigerant flows downward while swirling between the separation pipe 151 and the separation cylinder 152, and the refrigerant having a low specific gravity flows into the separation pipe 151, and flows out of the discharge port 112a through the flow passage 136b.
[0037]
On the other hand, the lubricating oil having a large specific gravity in the refrigerant is separated on the inner peripheral wall side of the separation cylinder 152 by centrifugal force, descends by gravity, and is stored in the oil storage chamber 160 through the discharge hole 154.
[0038]
Then, the lubricating oil stored in the oil storage chamber 160 is returned to the compressor section 130 through the return passage 170 and the throttle section 171 by the pressure difference between the oil storage chamber 160 and the suction chamber 141, and lubricates the compressor section 130. Do. The amount of lubricating oil to be recirculated is adjusted to a preset amount by the throttle portion 171 (gap area πdδ).
[0039]
Accordingly, the motor unit 120 does not need to have a strength that can withstand high pressure after the refrigerant is compressed, and the thickness t1 of the housing 112 can be reduced, so that an increase in the weight of the electric compressor 100 can be suppressed. In particular, in the electric compressor 100 which is used under a high pressure exceeding the critical pressure using CO ₂ as a refrigerant, the weight originally becomes very large in order to secure the pressure resistance, but the above-mentioned pressure resistance becomes unnecessary. A large weight reduction effect can be obtained.
[0040]
Also, since the lubricating oil in the refrigerant is separated on the discharge side and returned to the low-pressure side of the compressor unit 130 again, lubrication of the compressor unit 130 can be provided. It is possible to suppress a decrease in efficiency of the compressor and the compressor unit 130 itself, and to improve the system efficiency of the refrigeration cycle device.
[0041]
In addition, since a centrifugal separator is used as the oil separator 150, the oil separator 150 can be easily coped with an inexpensive structure.
[0042]
By the way, in the case where the refrigerant is handled under a high pressure, such as CO ₂ , if the throttle portion 171 of the recirculation passage 170 is reduced by ordinary drilling in order to recirculate a predetermined amount of lubricating oil, one having a very small hole diameter can be used. Although it becomes necessary and the processing becomes more difficult, since the aperture portion 171 is formed by the gap between the scrolls 135 and 136, the aperture portion 171 can be easily formed.
[0043]
Further, since the movable scroll 135 is provided on the side of the recirculation passage 170 that faces the opening 172, fine foreign matter contained in the lubricating oil easily flows with the lubricating oil along with the movement of the orbiting scroll 135. It is possible to prevent the opening 172 from being closed in the vicinity and blocked.
[0044]
The gap of the narrowed portion 171 can be adjusted by providing a step 135a on the movable scroll 135 as shown in FIG. 5, or by providing a notch 135b as shown in FIG. The opening 172 may be opened intermittently in response to the movement to improve the foreign matter discharging property.
[0045]
(2nd Embodiment)
FIG. 7 shows a second embodiment of the present invention. The second embodiment is different from the first embodiment in that an oil storage chamber 160 is formed so as to be included in the end housing 113.
[0046]
The compressor section 130 is provided with a communication passage 136c that communicates from the suction chamber 141 to the inside of the end housing 113, and the inside of the end housing 113 has a low-pressure side atmosphere, and the end housing 113 is the same as the front and middle housings 111 and 112. It is set at the plate pressure t1. An oil storage chamber cover (second housing) 161 is provided in a region inside the communication passage 136c, and an oil storage chamber 160 is formed therein. The plate pressure t3 of the oil storage chamber cover 161 is an intermediate thickness between the plate pressure t1 of the front and middle housings 111 and 112 and the plate pressure t2 of the end housing 113 in the first embodiment.
[0047]
As a result, the rear housing 113 of the compressor unit 130 may be capable of withstanding the pressure of the difference between the low pressure side pressure and the atmospheric pressure similarly to the motor unit 120, and direct leakage of the working fluid to the atmosphere side may be performed. Can increase the safety factor. Further, the thickness of the rear housing 113 can be unified with that of the motor section 120 to standardize the housing material.
[0048]
Further, since the oil storage chamber cover 161 receives a pressure of a difference between the high pressure side pressure and the low pressure side pressure, the oil storage chamber cover 161 should be made thinner in comparison with the one receiving the high pressure side pressure at atmospheric pressure. Can be.
[0049]
(Other embodiments)
In the first and second embodiments, the scroll type compressor unit 130 has been described. However, the present invention is not limited to this. As shown in FIG. 8, the rotor 182 revolves in the cylinder 181 and the rotor 182 rotates. May be a rotary compressor section 130 in which the suction chamber 141 and the compression chamber 142 are partitioned by a vane 183 that abuts against the suction chamber 141. At this time, the opening 172 of the recirculation passage 170 has a vane (movable member) on the suction chamber 141 side. ), The lubricating oil from oil storage chamber 160 can be recirculated.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an electric compressor according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing an AA part in FIG. 1;
FIG. 3 is an enlarged view showing the vicinity of a diaphragm in FIG. 1;
FIG. 4 is a model diagram showing an area of a gap in a narrowed portion.
FIG. 5 is an enlarged view showing a first modification of the vicinity of the throttle unit in FIG. 1;
FIG. 6 is an enlarged view showing a second modification of the vicinity of the throttle unit in FIG. 1;
FIG. 7 is a sectional view showing an electric compressor according to a second embodiment of the present invention.
FIG. 8 is a sectional view showing a compressor section according to another embodiment of the present invention.
[Explanation of symbols]
100 Electric compressor 113 End housing (outer shell, housing)
120 Motor unit 130 Compressor unit 135 Movable scroll (member, movable member)
136 Fixed scroll (member)
150 Oil separator (lubricating oil separator)
160 oil storage chamber 161 oil storage chamber cover (second housing)
170 Recirculation passage 171 Restricted part (gap part)
172 opening

Claims (6)

In an electric compressor in which CO ₂ is used as a working fluid and the sucked working fluid flows through a motor section (120) and is compressed by a compressor section (130),
A lubricating oil separator (150) for separating lubricating oil contained in the working fluid at a discharge side of the compressor unit (130);
An oil storage chamber (160) for storing the separated lubricating oil;
An electric compressor, comprising: a recirculation passage (170) for reducing the pressure of lubricating oil stored in the oil storage chamber (160) to a low pressure side of the compressor unit (130) and recirculating the lubricating oil. The electric compressor according to claim 1, wherein the lubricating oil separator (150) is of a centrifugal type. The throttle (171) for reducing the pressure in the return passage (170) is formed by opening the return passage (170) in the gap between the members (135, 140) in the compressor unit (130). The electric compressor according to claim 2, characterized in that the gap (171) is formed as a gap. The said member (135) of the side which opposes the opening part (172) of the said recirculation | recirculation passage (170) is a movable member (135) in the said compressor part (130), The Claim 3 characterized by the above-mentioned. Electric compressor. The compressor unit (130) is a scroll-type compressor unit (130);
The electric compressor according to claim 4, wherein the movable member (135) is a movable scroll (135). An outer shell (113) of the compressor section (135) is formed as a housing (113) for receiving a low pressure side pressure,
The electric compressor according to any one of claims 1 to 5, wherein the oil storage chamber (160) is formed by a second housing (161) contained in the housing (113).

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