JP3838174B2 - Electric compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric compressor applied to a refrigeration cycle apparatus using CO ₂ as a refrigerant.
[0002]
[Prior art]
As a technique related to a conventional electric compressor, as disclosed in Japanese Patent Application Laid-Open No. 2001-12352, a so-called suction cooling system is known in which a motor chamber is in a low-pressure atmosphere and the motor is cooled with suction refrigerant.
[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 can be kept to a minimum because it has a low-pressure atmosphere. It is possible to reduce the weight.
[0004]
[Problems to be solved by the invention]
However, in the suction cooling method, the motor chamber cannot be used as a separation chamber for oil contained in the discharged refrigerant, so that lubrication with the return oil by circulation in the system of the refrigeration cycle is necessary to lubricate the compressor. Therefore, the oil rate in the system could not be lowered. When the oil rate in the system is high, the heat exchange efficiency of the heat exchanger is lowered, the volume efficiency of the compressor itself is lowered, and the efficiency of the system is lowered.
[0005]
The object of the present invention is to improve the efficiency of the refrigeration cycle system while minimizing the increase in weight for ensuring pressure resistance even in the case where CO ₂ is used as a refrigerant under high pressure in view of the above problems. An object of the present invention is to provide an electric compressor.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention employs the following technical means.
[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 is circulated through the motor portion (120) and then compressed by the compressor portion (130), the compressor portion (130), a lubricant separator (150) for separating lubricant contained in the working fluid on the discharge side, an oil storage chamber (160) for storing the separated lubricant, and an oil storage chamber (160). A reflux passage (170) for reducing and refluxing the lubricating oil to the low pressure side of the compressor section (130) is provided , and an outer shell (113) of the compressor section (130) is a housing (113) that receives the pressure on the low pressure side. ) And the oil storage chamber (160) is formed by the second housing (161) included in the housing (113).
[0008]
As a result, the motor unit (120) does not need to be strong enough to withstand the high pressure after the working fluid is compressed, and the plate thickness of the housing (112) can be reduced, thereby increasing the weight of the electric compressor (100). 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 is originally very large to ensure the pressure resistance, but the above pressure resistance is not required. A significant weight reduction effect can be obtained. Further, the lubricating oil in the working fluid can be covered by separating the lubricating oil in the working fluid on the discharge side and returning it again to the low pressure side of the compressor section (130). It is possible to improve the system efficiency of the refrigeration cycle apparatus by reducing the rate to suppress the efficiency reduction of the heat exchanger and the compressor unit (130) itself. Further, the housing (113) of the compressor section (130) may be capable of withstanding the pressure difference between the low pressure side pressure and the atmospheric pressure as in the case of the motor section (120). The safety factor against leakage of the working fluid can be increased. In addition, the thickness of the housing (113) can be unified with that of the motor part (120) to standardize the housing material. Furthermore, since the second housing (161) receives a pressure that is the difference between the high-pressure side pressure and the low-pressure side pressure, the second housing (161) is thinner than the one that receives the high-pressure side pressure at atmospheric pressure. Can respond.
[0009]
In the invention described in claim 2, the housing (110) inside the low-pressure side atmosphere, the motor unit housed in a housing (110) and (120), housed in a housing (110), the CO ₂ An electric compressor including a compressor section (130) serving as a working fluid is separated from a lubricating oil separator (150) that separates lubricating oil contained in the working fluid on the discharge side of the compressor section (120). An oil storage chamber (160) for storing the lubricating oil, and a return passage (170) 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 same to the housing. The oil storage chamber (160) is formed by the second housing (161) contained in (110).
[0010]
As the lubricating oil separator (150), a centrifugal separation type is suitable as in the invention described in claim 3 , and can be easily handled with an inexpensive structure.
[0011]
By the way, in order to recirculate a predetermined amount of lubricating oil in the case where the working fluid is handled under high pressure, such as CO ₂ , it is very much possible to use a restriction by a normal hole drilling as a throttle part (171) of the reflux passage (170). Although a small-diameter hole is required, which increases the difficulty of processing. As in the invention described in claim 4 , the throttle portion (171) for reducing the pressure in the reflux passage (170) is provided in the reflux passage (170). If the gap portion (171) is formed by opening in the gap between the members (135, 140) in the compressor portion (130), the throttle portion (171) can be easily formed.
[0012]
And in invention of Claim 5 , the member (135) of the side facing the opening part (172) of a recirculation | reflux channel | path (170) is a movable member (135) in a compressor part (130). It is a feature.
[0013]
As a result, 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 it stagnates in the vicinity of the opening (172) and closes the opening (172). Can be prevented.
[0014]
As in the sixth aspect of the invention, it is preferable that the compressor section (130) is a scroll type compressor section (130) and the movable member (135) is applied as a movable scroll (135). The invention according to claim 7 is characterized in that the plate thickness (t1) of the housing (110) is thinner than the plate thickness (t3) of the second housing (161).
[0018]
In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
(First 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 apparatus (not shown) using CO ₂ as a refrigerant (working fluid), and a compressor in which a compressor unit 130 is operated by a motor unit 120 incorporated therein. It is said.
[0020]
The motor unit 120 and the compressor unit 130 are accommodated 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 refrigerant is sucked.
[0021]
A support plate 114 and a frame 115 to which bearings 132 and 133 are respectively fixed are provided on the front housing 111 side and an intermediate portion in the middle housing 112, and the drive shaft 131 is rotatably supported by the bearings 132 and 133. Has been.
[0022]
The motor unit 120 includes a rotor unit 121 and a stator unit 122 that are accommodated 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 by press-fitting on the outer peripheral side of the rotor part 121. When power from an external power source (not shown) is supplied to the stator unit 122, the drive shaft 131 is driven to rotate as the rotor unit 121 rotates. 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 constitutes a 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 the motor in the middle housing 112, and a movable scroll 135 as a movable member is disposed so as to engage with the fixed scroll 136.
[0024]
An eccentric portion 131 a provided at the tip of the drive shaft 131 is inserted through a bearing 134 on the side of the movable scroll 135 opposite to the fixed scroll. The movable scroll 135 revolves with respect to the fixed scroll 136 as the drive shaft 131 is driven by a rotation prevention 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 is formed with a flow passage 115 a through which the refrigerant flowing into the motor chamber 123 flows into the suction chamber 141.
[0026]
Further, the fixed scroll 136 is formed with a discharge port 136 a and a discharge chamber 143 through which the refrigerant compressed in the compression chamber 142 is discharged. 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 the partition plate 137.
[0027]
And while the compressed refrigerant is discharged from the discharge chamber 143 through the flow passage 136b and the discharge port 112a, an oil separator 150, an oil storage chamber 160, and a reflux passage 170, which are features of the present invention, are provided. .
[0028]
The oil separator 150 is a centrifugal lubricating oil separator that separates the lubricating oil contained in the refrigerant on the discharge side of the compressor unit 130, and is provided from the separation pipe 151, the separation cylinder 152, the introduction passage 153, and the discharge hole 154. Become.
[0029]
The separation pipe 151 is a pipe member having an outer diameter dimension set to two stages. The separation cylinder 152 is a cylindrical space formed by the biconcave portions provided in the fixed scroll 136 and the partition plate 137.
[0030]
The side with the larger outer diameter of the separation pipe 151 is press-fitted and fixed to the upper side of the separation cylinder 152, and the side with the smaller outer diameter of the separation pipe 151 extends downward in the separation cylinder 152. The separation pipe 151 communicates with the flow passage 136b and the discharge port 112a.
[0031]
As shown in FIG. 2, the separation cylinder 152 is provided with an introduction passage 153 so as to contact the inner peripheral surface of the separation cylinder 152 so that the discharge chamber 143 communicates with the inside of the separation cylinder 152. Further, a discharge hole 154 communicating with the inside of the 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 lubricating oil in the refrigerant separated by the oil separator 150. The oil storage chamber 160, since the introduction passage 153 from the discharge chamber 143, separating cylinder 152, the discharge pressure of the refrigerant through the discharge hole 154 (high-pressure side pressure) is added, the thickness t2 of the end housing 113, before compression It is set larger than the plate thickness t1 of the front and middle housing 111,112 refrigerant pressure (low-pressure side pressure) is added.
[0033]
The recirculation passage 170 is configured to reduce the pressure of the lubricating oil stored in the oil storage chamber 160 to the low pressure side of the compressor unit 130 and to recirculate the recirculation passage 170, and includes an oil supply passage 170a and an oil supply pipe 170b. The oil supply passage 170 a is provided in the vicinity of the suction chamber 141 of the fixed scroll 136. As shown in FIG. 3, the oil supply passage 170 a faces the movable scroll 135, forms an opening 172 in a gap δ generated between the scrolls 135 and 136 by thrust force during operation, and communicates with the suction chamber 141. Yes. In addition, the oil supply passage 170a is connected to the lower vicinity of the oil storage chamber 160 to which the oil supply pipe 170b is connected.
[0034]
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 170a is used for pressure reduction from the oil storage chamber 160 to the suction chamber 141. An aperture 171 is provided.
[0035]
Next, the operation and effect based on the above configuration will be described. In the electric compressor 100, the movable scroll 135 is revolved by driving the motor unit 120, and the refrigerant flowing into the suction chamber 141 through the suction port 111a, the flow passage 114a, the motor chamber 123, and the flow passage 115a is compressed in the compression chamber 142. . At this time, the refrigerant flows through the motor unit 120, whereby 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 cylinder 152 through the introduction passage 153 of the oil separator 150. At this time, the refrigerant flows downward while rotating between the separation pipe 151 and the separation cylinder 152, and the refrigerant having a small specific gravity flows into the separation pipe 151 and flows out from the discharge port 112a through the flow passage 136b.
[0037]
On the other hand, lubricating oil having a large specific gravity in the refrigerant is separated to the inner peripheral wall side of the separation cylinder 152 by centrifugal force, descends due to gravity, and is stored in the oil storage chamber 160 from the discharge hole 154.
[0038]
The lubricating oil stored in the oil storage chamber 160 is returned to the compressor portion 130 through the return passage 170 and the throttle portion 171 due to the pressure difference between the oil storage chamber 160 and the suction chamber 141, and lubricates the compressor portion 130. Do. The amount of lubricating oil to be recirculated is adjusted to a preset amount by the throttle portion 171 (gap portion area πdδ).
[0039]
As a result, the motor unit 120 does not need to have sufficient strength to withstand the high pressure after the refrigerant is compressed, and the plate thickness t1 of the housing 112 can be reduced. Therefore, an increase in the weight of the electric compressor 100 can be suppressed. In particular, in the electric compressor 100 that is used under a high pressure exceeding the critical pressure using CO ₂ as a refrigerant, the weight is originally very large in order to ensure the pressure resistance, but the above-described pressure resistance is unnecessary. A large weight reduction effect can be obtained.
[0040]
Further, the lubricating oil in the refrigerant is separated on the discharge side and recirculated back to the low pressure side of the compressor unit 130, so that the compressor unit 130 can be lubricated, so that the oil rate in the refrigerant is lowered and heat exchange is performed. The efficiency reduction of the compressor and the compressor unit 130 itself can be suppressed, and the system efficiency of the refrigeration cycle apparatus can be improved.
[0041]
Further, since a centrifugal separator is used as the oil separator 150, it can be easily handled with an inexpensive structure.
[0042]
By the way, in the case where the refrigerant is handled under high pressure, such as CO ₂ , when the throttle part 171 of the reflux passage 170 is adapted to be throttled by normal hole processing in order to recirculate a predetermined amount of lubricating oil, there is an extremely small hole diameter. Although it becomes necessary and the degree of difficulty of processing increases, here, since the narrowed portion 171 is formed by the gap between the scrolls 135 and 136, the narrowed portion 171 can be easily formed.
[0043]
Furthermore, since the side facing the opening 172 of the reflux passage 170 is the movable scroll 135, minute foreign matter contained in the lubricating oil easily flows with the lubricating oil as the movable scroll 135 moves, and the opening 172. It is possible to prevent the opening 172 from being blocked in the vicinity.
[0044]
As shown in FIG. 5, the gap portion of the throttle portion 171 is adjusted by providing a step portion 135a on the movable scroll 135, or as shown in FIG. The opening 172 may be intermittently opened in accordance with the exercise to improve the foreign matter discharge performance.
[0045]
(Second Embodiment)
A second embodiment of the present invention is shown in FIG. The second embodiment is formed so that the oil storage chamber 160 is included in the end housing 113 with respect to the first embodiment.
[0046]
The compressor section 130 is provided with a communication path 136c that communicates from the suction chamber 141 into the end housing 113. The end housing 113 is the same as the front and middle housings 111 and 112, with the inside of the end housing 113 being a low-pressure atmosphere. It is set in the plate thickness t1. An oil storage chamber cover (second housing) 161 is provided in a region inside the communication path 136c, and the oil storage chamber 160 is formed therein. The thickness t3 of the oil reservoir cover 161, the front, is set to an intermediate thickness between the thickness t2 of the end housing 113 of a plate thickness t1 of the aforementioned first embodiment of the middle housing 111.
[0047]
As a result, the rear housing 113 of the compressor unit 130 is only required to be able to withstand the pressure difference between the low pressure side pressure and the atmospheric pressure similarly to the motor unit 120, and the working fluid leaks directly to the atmosphere side. The safety factor against can be increased. Further, the plate thickness of the rear housing 113 can be unified with that of the motor unit 120 so that the housing material can be standardized.
[0048]
Furthermore, since the oil storage chamber cover 161 receives a pressure that is the difference between the high-pressure side pressure and the low-pressure side pressure, the oil storage chamber cover 161 is made thinner than the one that receives the high-pressure side pressure at atmospheric pressure. Can do.
[0049]
(Other embodiments)
In the first and second embodiments described above, the scroll type compressor unit 130 is used. However, the present invention is not limited to this, and the rotor 182 revolves in the cylinder 181 as shown in FIG. The rotary compressor section 130 may be configured such that the suction chamber 141 and the compression chamber 142 are partitioned by a vane 183 that contacts the vane 183, and the opening 172 of the reflux passage 170 at this time is a vane (movable member) on the suction chamber 141 side. ) If it opens so as to face the side surface of 183, the lubricating oil from the oil storage chamber 160 can be recirculated.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an electric compressor according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing an AA portion in FIG.
FIG. 3 is an enlarged view showing the vicinity of a diaphragm portion in FIG. 1;
FIG. 4 is a model diagram showing a gap area in a throttle portion.
FIG. 5 is an enlarged view showing a modified example 1 in the vicinity of the aperture portion in FIG. 1;
6 is an enlarged view showing a modified example 2 in the vicinity of the aperture portion in FIG. 1. FIG.
FIG. 7 is a cross-sectional view showing an electric compressor according to a second embodiment of the present invention.
FIG. 8 is a cross-sectional view showing a compressor unit according to another embodiment of the present invention.
[Explanation of symbols]
100 Electric compressor 113 End housing (outer shell, housing)
120 motor part 130 compressor part 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 Reflux passage 171 Restriction part (gap part)
172 opening

Claims (7)

In the electric compressor in which CO ₂ is used as a working fluid and the sucked working fluid is circulated through the motor unit (120) and then compressed by the compressor unit (130).
A lubricant separator (150) for separating the lubricant contained in the working fluid on the discharge side of the compressor section (130);
An oil storage chamber (160) for storing the separated lubricating oil;
A reflux passage (170) for reducing and recirculating the lubricating oil stored in the oil storage chamber (160) to the low pressure side of the compressor section (130) ;
The outer shell (113) of the compressor section (130) is formed as a housing (113) that receives a low-pressure side pressure,
The electric compressor, wherein the oil storage chamber (160) is formed by a second housing (161) contained in the housing (113). A housing (110) having a low-pressure atmosphere inside;
  A motor part (120) housed in the housing (110);
  Contained in the housing (110), CO ₂ An electric compressor comprising a compressor section (130) having a working fluid as a working fluid,
  A lubricant separator (150) for separating the lubricant contained in the working fluid on the discharge side of the compressor section (120);
  An oil storage chamber (160) for storing the separated lubricating oil;
  A reflux passage (170) for reducing and recirculating the lubricating oil stored in the oil storage chamber (160) to the low pressure side of the compressor section (130);
  The electric compressor, wherein the oil storage chamber (160) is formed by a second housing (161) contained in the housing (110). The electric compressor according to claim 1 or 2 , wherein the lubricating oil separator (150) is a centrifugal type. The throttle part (171) for pressure reduction in the return passage (170) is formed by opening the return passage (170) into a gap between the members (135, 140) in the compressor part (130). The electric compressor according to claim 3 , wherein the electric compressor is a gap portion (171). Wherein the member of the opening (172) and opposing sides of the recirculation passage (170) (135) is according to claim 4, wherein a movable member in the compressor section (130) (135) Electric compressor. The compressor section (130) is a scroll compressor section (130),
The electric compressor according to claim 5 , wherein the movable member (135) is a movable scroll (135).   The plate thickness (t1) of the housing (110) is thinner than the plate thickness (t3) of the second housing (161), according to any one of claims 1 to 6. Compressor.

Images