JP2003328965A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce dead volume without increasing passage resistance of a discharge port, to reduce re-compression loss due to expansion of fluid remaining in the dead volume, and to enhance compression efficiency of a scroll compressor. <P>SOLUTION: A compression space 3 is defined by a fixed scroll 1 and a turning scroll 2. The fixed scroll 1 sucks and compresses fluid through volume change of the compression space caused by turning motion of the turning scroll 2. The fixed scroll is provided with a discharge port 11 for discharging compressed fluid and a discharge 50 valve for preventing backflow of the discharged fluid. The discharge port 11 has passages of a central portion 11b, an inlet, enlarged portion 11c and an outlet, enlarged portion 11d, which are enlarged in their cross sections than the central portion 11b. With this, the scroll compressor reduces inflow resistance and discharge resistance and substitutes the resistance reduction for reduction of the dead volume. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a compression space by engaging a fixed scroll and an orbiting scroll, and reduces the volume of the compression space from the outer peripheral portion toward the center portion by the circular orbital motion of the orbiting scroll. The present invention relates to a scroll compressor that utilizes movement to repeatedly suck, compress, and discharge a fluid.

[0002]

2. Description of the Related Art As shown in FIG. 8, a conventional scroll compressor 60 includes a hermetically sealed container 12, a compression mechanism portion 14 including a fixed scroll 1 and an orbiting scroll 2, an electric motor including a stator 18 and a rotor 19. 17 and rotor 19
The crankshaft 8 that is connected to the
It is provided as a main component. This scroll compressor 6
At 0, a plurality of compression spaces 3 are formed between both the fixed scroll 1 and the orbiting scroll 2 that are meshed with each other. The orbiting scroll 2 is driven by the eccentric portion 9 of the crankshaft 8 via the orbiting bearing 7 in a state in which the rotation preventing member 4 prevents the orbiting scroll 2, and makes a circular orbital movement, that is, an orbiting movement with respect to the fixed scroll 1. The orbiting movement of the orbiting scroll 2 causes the compression space 3 to move from the outer peripheral side toward the center of the spiral, thereby reducing the volume,
A fluid such as a refrigerant gas flows from the suction pipe 15 to the suction port 10.
After that, it is sucked into the orbiting scroll 2 and compressed. Then, the refrigerant gas that has increased to the discharge pressure lifts the discharge valve 50 and is discharged from the internal space 13 of the closed container 12 through the discharge port 11 through the discharge pipe 16. Compression mechanism portion 14 including the fixed scroll 1 having the discharge port 11
As such, one having a structure shown in the cross-sectional view of FIG. 9 (for example, JP-A-7-189937) is known. According to this conventional configuration, the compression mechanism portion 14 includes the fixed scroll 1
And a revolving scroll 2 that meshes with the fixed scroll 1. The fixed scroll 1 has a discharge port 11 provided near the center thereof and a discharge valve made of an elastic body having one longitudinal end fixed to the fixed scroll 2. 50 and valve retainer 5
1 and. The discharge port 11 is composed of the passages of the outlet expansion portion 11a and the central portion 11b, and has a shape in which the passage cross-sectional area is gradually expanded and changed from the central portion 11b to the outlet expansion portion 11a in the flow direction of the refrigerant gas. ing.
The outlet expansion portion 11a serves to widen the pressure receiving area of the discharge valve 50 that receives the pressure of the refrigerant gas and to smoothly open the discharge valve 50 when the compression is completed.

[0003]

However, although the outlet expansion portion of the discharge port helps to smoothly open the discharge valve, it leads to an increase in the total passage volume of the discharge port, that is, a dead volume that is not compressed, and also inflow resistance. Impact,
There was room for improvement in the performance of the scroll compressor and reduction in dead volume, as it led to an increase in overall passage resistance and a limit to reducing dead volume. Further, the influence of recompression loss due to expansion of the refrigerant gas remaining in the dead volume is due to the refrigerant having a low condensation pressure as the discharge pressure (for example, R4
10a), it appears significantly in a high-pressure refrigerant (for example, carbon dioxide refrigerant). In other words, the scroll compressor has a problem in compressing to a critical pressure by using carbon dioxide as a refrigerant from the viewpoint of recompression loss because there is a limit in reducing the dead volume.

Therefore, an object of the present invention is to reduce the passage resistance of the discharge port and provide a scroll compressor with good performance. Another object is to provide a scroll compressor having a high compression efficiency by reducing the dead volume without increasing the passage resistance of the discharge port. Another object of the present invention is to provide a scroll compressor capable of compressing carbon dioxide to a critical pressure by using carbon dioxide as a refrigerating cycle refrigerant.

[0005]

According to the scroll compressor of the present invention as set forth in claim 1, a fixed scroll and an orbiting scroll are meshed with each other to form a compression space, which is continuously generated by the orbiting motion of the orbiting scroll. A scroll compressor that sucks and compresses a fluid according to a change in volume and discharges the compressed fluid from a discharge port provided in the fixed scroll, wherein the fluid is introduced into the discharge port at a side closer to the fluid inlet side than the central portion. It is characterized in that an enlarged entrance portion having a wide cross-sectional area is formed. According to a second aspect of the present invention, in the scroll compressor according to the first aspect, the inlet expansion portion has a conical shape. The present invention according to claim 3 provides the scroll compressor according to claim 1,
An outlet expansion portion having a passage cross-sectional area larger than that of a central portion is formed on the fluid outflow side of the discharge port, and the outlet expansion portion has a conical shape. According to a fourth aspect of the present invention, in the scroll compressor according to the first aspect, an outlet expansion portion having a passage cross-sectional area wider than a central portion is formed on the discharge port side of the fluid of the discharge port, and the outlet expansion portion is formed. And a discharge valve for preventing backflow to the discharge port. The present invention according to claim 5 relates to claim 1.
From the above, in the scroll compressor according to any one of claims 4 to 6, carbon dioxide is used as the fluid, and compressed to a critical pressure.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In a scroll compressor according to a first embodiment of the present invention, an inlet enlarged portion having a passage sectional area larger than that of a central portion is formed on a fluid inlet side of a discharge port. According to the present embodiment, since the inlet expansion portion having a wider passage cross-sectional area than the central portion is provided, the inflow resistance of the refrigerant gas flowing into the discharge port can be reduced, and the entire discharge port can be expanded. It is possible to reduce the dead volume as compared with the case.

The second embodiment of the present invention is such that, in the scroll compressor according to the first embodiment, the enlarged inlet portion has a conical shape. According to the present embodiment, since the flow of the fluid flowing into the discharge port is gradually reduced, it is possible to suppress the generation of vortices and reduce the inflow resistance, and the conical inlet enlarged portion is processed with a drill. Therefore, the processing can be performed at a low cost.

A third embodiment of the present invention is the scroll compressor according to the first embodiment, wherein an outlet expansion portion having a passage cross-sectional area larger than that of the central portion is formed on the fluid outlet side of the discharge port. The outlet enlarged portion has a conical shape. According to the present embodiment, since the flow of the fluid flowing out from the discharge port is gradually expanded, it is possible to suppress the generation of vortices and reduce the outflow resistance, and the conical outlet expansion part is processed by a drill. Therefore, the processing can be performed at a low cost.

A fourth embodiment of the present invention is the scroll compressor according to the first embodiment, wherein an outlet expansion portion having a passage sectional area larger than that of the central portion is formed on the fluid outflow side of the discharge port. The outlet expansion portion is provided with a discharge valve for preventing backflow to the discharge port. According to the present embodiment, the discharge valve can be smoothly opened, and the dead volume can be reduced as compared with the case where the entire discharge port is expanded.

The fifth embodiment of the present invention is to use the scroll compressor according to the first to fourth embodiments to compress carbon dioxide as a fluid to a critical pressure. When carbon dioxide, which has a high refrigerant density in the discharge process, is used as the refrigerant, it is easily affected by dead volume. However, according to the present embodiment, the entire discharge port is expanded by the first to fourth embodiments. Since the dead volume is made smaller than the case, the compression loss due to re-expansion can be effectively reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of a scroll compressor according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the scroll compressor of this embodiment. In the scroll compressor 60 shown in FIG. 1, a closed container 12 having a suction pipe 15, a discharge pipe 16 and the like.
The compression mechanism portion 14 and the electric motor 17 are disposed inside the. The electric motor 17 is composed of a stator 18 fixed inside the closed casing 12 and a rotor 19 rotatably supported inside the stator 18. And the rotor 1
The crankshaft 8 is connected to 9 in a penetrating state. One end of the crankshaft 8 is rotatably supported by a bearing 20 fixed to a bearing member 21 that constitutes a part of the compression mechanism portion 14. At the tip of the crankshaft 8 supported by the bearing 20, an eccentric part 9 for performing an eccentric movement with respect to this shaft is provided.
Is provided. Further, in the compression mechanism portion 14, the fixed scroll 1 and the orbiting scroll 2 which are meshed with each other form a plurality of compression spaces 3. Orbiting scroll 2
Is prevented from rotating by the rotation preventing member 4, and performs a turning motion by the rotational motion of the eccentric portion 9 via the turning bearing 7. With the orbiting motion of the orbiting scroll 2, the compression space 3 moves toward the center of the spiral while gradually reducing the volume of the space, and the refrigerant gas as a fluid is sucked from the suction pipe 15 via the suction port 10. Then, it is compressed toward the center of the orbiting scroll 2. The compressed refrigerant gas is discharged from the internal space 13 of the closed container 12 through the discharge pipe 16 through the discharge port 11, the discharge valve 50, and the valve retainer 51 provided near the center of the fixed scroll 1. It

On the other hand, the bottom end of the crankshaft 8 has a ball bearing 2
3 and is provided with a positive displacement pump 22 at its tip. Lubricating oil accumulated in a bottom liquid reservoir 25 provided at the bottom of the hermetic container 12 is passed by the positive displacement pump 22 through a liquid supply passage 27 for lubricating oil provided at the center of the crankshaft 8 to the crankshaft. The liquid is supplied to the upper liquid pool portion 28 of the eccentric portion 9 located at the upper end of 8. Then, the lubricating oil in the upper liquid pool portion 28 lubricates and cools the slewing bearing 7. Further, after the bearing 20 is lubricated from the orbiting bearing 7 through the liquid reservoir space 29, the bearing 20 returns to the bottom liquid reservoir 25.

The orbiting mirror surface portion 33 below the orbiting scroll is
It is separated from the upper surface of the bearing member 21 with a predetermined gap,
This gap is sealed by an annular seal member 38 placed in the groove of the bearing member 21. The bearing member 21 is provided with a recess 34, and the rotation preventing member 4 is disposed in the recess 34. Further, a part of the recess 34 forms a back pressure chamber 32 as a space surrounded by the fixed mirror surface portion 37, the orbiting mirror surface portion 33 and the bearing member 21 in the lower portion of the fixed scroll. The liquid reservoir space 29 and the back pressure chamber 32 are provided with a seal member 38.
The upper liquid pool portion 28, the liquid pool space 29 and the back pressure chamber 32 are communicated with each other by a long hole 30 and a throttle portion 31 provided inside the orbiting scroll 2. The liquid pool space 29 communicates with the internal space 13 via the bearing 20 and the like, and the upper liquid pool part 28, the liquid pool space 29 and the internal space 13 form a high pressure space, and the back pressure chamber 32 and the recess 34.
Forms an intermediate pressure space. A part of the lubricating oil supplied to the upper liquid pool portion 28 is supplied to the back pressure chamber 32 and the depression 34 from the elongated hole 30 via the throttle portion 31, and the rotation prevention member 4 of the rotation prevention member 4 arranged in the depression 34. Lubricating. As the lubricating oil supplied to the back pressure chamber 32 accumulates, the pressure in the back pressure chamber 32 increases. In order to adjust the pressure of the back pressure chamber 32, a pressure adjusting mechanism 39 that allows the back pressure chamber 32 and the compression space 3 to pass through the suction passage 40 is provided. That is, when the pressure of the back pressure chamber 32 becomes higher than the set pressure of the pressure adjusting mechanism 39, the pressure adjusting mechanism 39 operates and the back pressure chamber 32 communicates with the compression space 3, and the lubricating oil in the back pressure chamber 32 is sucked. It is supplied to the compression space 3 through the passage 40, and the back pressure chamber pressure is kept substantially constant. The lubricating oil guided from the suction passage 40 to the compression space 3 plays a role of a seal for preventing leakage of the refrigerant gas during compression and a role of lubricating the contact surfaces of the fixed scroll 1 and the orbiting scroll 2.

Further, the discharge pressure of the scroll compressor, the pressure of the liquid pool space 29, the pressure of the back pressure chamber 32, and the pressure of the suction passage 40 are appropriately set, but the pressure of the back pressure chamber 32 is particularly set. Is pressed against the fixed scroll 1, the pressure is set higher than the suction space pressure by a predetermined pressure. Liquid reservoir space 29 and back pressure chamber 3 to obtain a predetermined pressure
It is adjusted by the dimensions of the elongated hole 30 and the narrowed portion 31 that allow the two to communicate with each other, and the set pressure of the pressure adjusting mechanism 39. As shown in FIG. 7, the throttle portion 31 has a threaded portion 31a on the outer peripheral portion.
And a pin-shaped member having a small hole 31b and a large hole 31c in the center. That is, as shown in FIG. 1, the lubricating oil in the liquid reservoir 28 is the same as the pores 31 b in the throttle 31.
After being decompressed by the throttling effect when the flow rate is throttled through, the appropriate amount is supplied to the back pressure chamber 32 through the thick hole 31c. The proper amount of this lubricating oil is the fine holes 31b.
It is adjusted by setting the diameter of.

Next, the structure and operation of the compression mechanism portion of this embodiment, particularly the fixed scroll, will be described with reference to FIGS. 2 and 3. 2 is a sectional view showing a compression mechanism portion of the scroll compressor shown in FIG. 1, and FIG. 3 is a view of the compression mechanism portion shown in FIG. The compression mechanism portion 14 shown in FIG. 2 includes a fixed scroll 1 having a discharge port 11 bored in the vicinity of the central portion thereof, and an orbiting scroll 2 meshed with the fixed scroll 1. And
The fixed scroll 1 of the present embodiment includes a discharge valve 50 fixed so as to close the discharge port 11 and a valve retainer 51 that protects the discharge valve 50. Further, the discharge port 11 of the fixed scroll 1 is composed of an outlet expansion part 11c, a central part 11b, and an inlet expansion part 11d, which are connected to each other in the flow direction of the fluid (for example, refrigerant gas). An inlet expansion portion 11d having a wider passage cross-sectional area in the direction perpendicular to the fluid flow than the portion 11b is formed, and an outlet expansion portion 1 having a wider passage cross-sectional area than the central portion 11b is formed on the fluid outflow side.
It has a passage forming 1c. In the discharge port 11 having the above structure, when the compression stroke ends and the discharge stroke starts, the refrigerant gas flows into the discharge port 11 from the compression space 3. At this time, since the passage cross-sectional area of the inlet expansion portion 11d of the discharge port 11 is larger than that of the central portion 11b, when the refrigerant gas flows into the discharge port 11 from the compression space 3,
Inflow resistance can be reduced. After that, the refrigerant gas flows into the central portion 11b of the discharge port 11 whose passage cross-sectional area is gradually reduced from the inlet enlarged portion 11d, and further, the outlet enlarged portion 11c whose passage cross-sectional area is gradually enlarged from the central portion 11b. And is discharged from the discharge valve 50 into the internal space 13. At this time, since the flow of the refrigerant gas flowing out from the discharge port 11 gradually expands, it is possible to suppress the generation of vortices and reduce the outflow resistance. Also, the outlet expansion part 1
Since the passage sectional area of 1c is enlarged, the refrigerant gas exerts a large pressure on the discharge valve 50, and the discharge valve 50 can be opened smoothly.

Since the passage resistance including the inflow resistance can be reduced, the dead volume can be reduced as compared with the case where the entire discharge port is expanded. In other words, the dead volume of the discharge port can be reduced without increasing the passage resistance of the entire discharge port.
As a result, recompression loss due to expansion of the refrigerant gas remaining in the dead volume can be reduced, and a scroll compressor having high compression efficiency can be provided. In addition, in the present embodiment, the fixed scroll 1 of the compression mechanism portion 14 is provided with the discharge valve 50 and the valve retainer 51, and the discharge valve 50 is closed and serves as a check valve in the intake or compression strokes other than the discharge stroke. By acting, the backflow of the refrigerant gas from the discharge port 11 to the compression space 3 is prevented,
Realizes a scroll compressor that can secure even higher compression efficiency. Further, the dead volume of the discharge port refers to a space (total passage volume) formed by the passages of the outlet expansion portion 11c, the central portion 11b, and the inlet expansion portion 11d when the discharge valve 50 is closed. Therefore, the effect of reducing the recompression loss is relatively large in the scroll compressor having the discharge valve 50.

By the way, the inlet expansion portion 11d of the discharge port
The enlarged dimension of will be described with reference to FIG. In FIG. 3, as the orbiting scroll 2 orbits, the compression space 3 surrounded by the fixed scroll 1 is moved toward the center of the spiral, and the volume of the space is gradually reduced by the compression stroke. The discharge stroke in which the gas is compressed and the compressed refrigerant gas flows into the central portion 11b from the inlet expansion portion 11d is shown. In FIG. 3, the inlet outer edge portion 11da is a regular dimension (diameter d) of the inlet expansion portion 11d.
It shows the edge of the hole made in. In addition, the outer edge 11 of the entrance
ma represents the edge of the hole of the inlet enlarged portion 11d that has been machined with an irregular dimension having a diameter D larger than the diameter d. If the edge of the hole is processed to be large like the inlet outer edge portion 11ma, the edge of the hole will protrude from the orbit range drawn during the compression stroke of the orbiting scroll outer wall 2a, and the refrigerant gas will leak and be compressed. Becomes insufficient. That is, the entrance expansion part 1
There is a limit to the expansion of 1d, and it is preferable that the size of (the outer edge portion of the entrance) of the entrance expansion portion is within the range of the orbit that the orbiting scroll draws during the compression stroke.

Next, a scroll compressor according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 4, only the fixed scroll 1 of the scroll compressor of the second embodiment is shown, the other parts are the same as those of the first embodiment, and the illustration and description thereof are omitted. FIG. 4 is a sectional view showing a fixed scroll according to another embodiment of the present invention. The discharge port 11 of the fixed scroll 1 of the present embodiment is composed of an inlet expansion part 11f, a central part 11b, and an outlet expansion part 11e, which are connected to each other and are perforated, and the inlet expansion part 11f and the outlet expansion part 11e.
The cross-sectional area of the passage perpendicular to the streamline is larger than that of the central portion 11b. These entrance expansion parts 11f
The outlet expansion part 11e is manufactured by processing with an end mill, for example, and both passages have a so-called stepped counterbore structure. The fixed scroll 1 of the second embodiment is different from the fixed scroll 1 of the first embodiment in that it does not include the discharge valve 50 and the valve retainer 51.

In the fixed scroll 1 of this embodiment,
In the discharge stroke after the compression process is completed, since the passage cross-sectional area of the inlet expansion portion 11f of the discharge port 11 is expanded,
The inflow resistance when the refrigerant gas as the fluid flows from the compression space 3 to the discharge port 11 can be reduced. After that, the refrigerant gas flows into the central portion 11b whose cross-sectional area is gradually reduced. Further, it is possible to suppress the formation of vortices and reduce the discharge resistance of the refrigerant gas at the outlet expansion portion 11e in which the passage cross-sectional area is gradually expanded.
That is, the inflow resistance and the outflow resistance are reduced and the discharge amount is increased accordingly, so that the performance of the scroll compressor can be improved. Since the fixed scroll 1 of this embodiment does not have the discharge valve 50 as described above, the outlet expansion portion 1 of this embodiment is
1e is preferable from the viewpoint of reducing the dead volume, because the outer diameter dimension of the outlet expansion portion 11c of the fixed scroll 1 including the discharge valve 50 shown in FIG. 2 can be made smaller.

Next, a scroll compressor according to a third embodiment of the present invention will be described with reference to FIG. Figure 5
Is a cross-sectional view showing a fixed scroll of another embodiment of the present invention, showing only the fixed scroll portion of the scroll compressor of the present invention, other parts are the same as the second embodiment, Description and the like are omitted. The fixed scroll 1 of the embodiment shown in FIG. 5 has an inlet enlarged portion 11h and a central portion 11b.
And a discharge port 11 constituted by each passage of the outlet expansion portion 11g. The passage cross-sectional areas of both the passages of the outlet enlarged portion 11g and the inlet enlarged portion 11h have a central portion 11
It is enlarged in a conical shape from the passage sectional area of b. That is, it has a conical counterbore structure. This conical counterbore is made by machining with a drill, for example. In the case of the fixed scroll 1 of the present embodiment, the inflow resistance becomes small in the entrance enlarged portion 11h, and the vortex formation is suppressed and the discharge resistance becomes small in the outlet enlarged portion 11g. That is, the passage resistance of the entire discharge port including the inflow resistance and the discharge resistance is reduced, the discharge amount is increased accordingly, and a scroll compressor with good performance can be obtained.

By the way, the outlet expansion portion 11 of the third embodiment.
In comparison with the stepped counterbore of the outlet enlarging portion 11e and the inlet enlarging portion 11f of the second embodiment, the conical counterbore of g and the inlet enlarging portion 11h does not have a sharp reduction or enlargement of the cross-sectional area, and its streamline. Will be smooth. Therefore, the conical counterbore is a preferable structure because it further reduces the passage resistance of the entire discharge port. Further, the conical counterbore processing with a drill is desirable because it can be processed with a drill blade tip and is easier and cheaper than the stepped counterbore processing with an end mill. Therefore, it can be said that the conical counterbore structure which can obtain both the performance and the processing advantages at the same time is preferable. Although not illustrated, a discharge port having only a conical counterbore structure at the inlet enlarged portion or a discharge port having only a conical counterbore structure at the outlet enlarged portion is also possible. Similar to the third embodiment, the performance and processing can be improved. Further, the conical counterbore of the present invention has a chamfer for removing burrs and barbs on the edge of the hole with a drill or the like (general dimensions;
It has a larger size and structure than 1 to 0.2 mm).

Next, a scroll compressor according to a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 6, only the fixed scroll portion of the scroll compressor of the fourth embodiment is shown, and other portions are the same as those of the first embodiment,
Description and the like are omitted. FIG. 6 is a sectional view showing a fixed scroll according to another embodiment of the present invention. The discharge port 11 of the fixed scroll 1 according to the present embodiment is composed of an inlet expansion portion 11i having a shape in which the passage cross-sectional area is enlarged, and a central portion 11b. That is, the inlet enlarged portion 11i has a so-called inlet orifice structure in which the passage cross-sectional area in the direction perpendicular to the streamline is smoothly enlarged. Even with the fixed scroll 1 of the present embodiment, the inflow resistance in the inlet expansion portion 11i is small. Therefore, the discharge amount increases as the inflow resistance decreases, and the performance of the scroll compressor can be improved. By the way, the scroll compressor described in the above embodiment is a refrigerant whose condensing pressure operates at a critical pressure,
For example, carbon dioxide can be used. Typically,
The working pressure of the refrigerant of carbon dioxide becomes high in the discharge stroke of the scroll compressor, and its density becomes high. Therefore, in the next compression stroke, the high-density refrigerant remaining in the dead volume expands and is recompressed. The compression loss ratio is determined by the refrigerant operating at a low condensation pressure, for example, R41.
It tends to be larger than 0a.

In the present embodiment, however, the fixed scroll of the scroll compressor has the discharge port in which the dead volume is made small while suppressing the passage resistance. Therefore, carbon dioxide, which has a high density at high pressure, is used as the refrigerant. Even when used, it is possible to prevent an increase in recompression loss.
In other words, since the dead volume is small and the recompression loss can be suppressed, it is possible to provide a scroll compressor which uses carbon dioxide as a refrigerant and can be compressed to a critical pressure. In other words, it can be said that it is possible to provide a refrigeration system or the like that is composed of a combination of carbon dioxide as an environment-friendly refrigerant and a scroll compressor capable of silent operation. It should be noted that the fluid used in the scroll compressor has a discharge pressure (or condensation pressure in the refrigeration cycle) in the discharge stroke that is equal to or higher than the discharge pressure of the refrigerant of carbon dioxide, that is, the density at high pressure is high. It is clear that the same effect as described above can be obtained if the fluid becomes higher, and the present invention is not limited to the carbon dioxide refrigerant. Further, in each of the above-described embodiments, the case where the scroll compressor of the present invention is applied to a hermetic scroll compressor used in a refrigerating device, a refrigerating machine, an air conditioner or the like is illustrated. Therefore, although the fluid to be handled is described as the refrigerant, the present invention is not limited to the refrigerant.

[0024]

As described above, according to the scroll compressor of the present invention, the discharge port is provided with the inlet expansion portion having the enlarged passage cross-sectional area, so that the refrigerant gas can flow from the compression space to the discharge port. Since it is performed smoothly, the inflow resistance can be reduced. That is, there is an effect that the passage resistance of the discharge port can be reduced and the discharge amount can be increased by that amount to provide a scroll compressor with good performance. In addition, the reduction of the passage resistance of the discharge port leads to a reduction in the dead volume of the discharge port without increasing the passage resistance, and the recompression loss due to the expansion of the fluid remaining in the dead volume is reduced. Therefore, there is an effect that a highly efficient scroll compressor can be provided. In addition, by providing a discharge valve with a backflow prevention function (that is, a check valve), the discharge valve can be opened smoothly to minimize discharge resistance and prevent backflow to the compression space, and also to prevent dead volume. There is an effect that the scroll compressor provided with the discharge valve in which the influence of (1) appears remarkably has high efficiency. Further, since the scroll compressor of the present invention has a small dead volume, it is possible to reduce the recompression loss, and use a high-pressure working gas such as carbon dioxide as a refrigerant to compress it to a critical pressure. The effect that can be obtained is obtained. Therefore, there is also an effect that it is possible to provide a refrigeration system including a combination of carbon dioxide as an environment-friendly refrigerant and a scroll compressor capable of quiet operation.

[Brief description of drawings]

FIG. 1 is a sectional view showing a scroll compressor according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a compression mechanism portion of the scroll compressor shown in FIG.

FIG. 3 is a diagram showing the compression mechanism section shown in FIG.

FIG. 4 is a sectional view showing a fixed scroll according to another embodiment of the present invention.

FIG. 5 is a sectional view showing a fixed scroll according to another embodiment of the present invention.

FIG. 6 is a sectional view showing a fixed scroll according to another embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a throttle unit according to an embodiment of the present invention.

FIG. 8 is a sectional view showing a conventional scroll compressor.

9 is a cross-sectional view showing a compression mechanism portion of the scroll compressor shown in FIG.

[Explanation of symbols]

1 fixed scroll 2 orbiting scroll 2a Orbiting scroll outer wall 2b Orbiting scroll inner wall 3 compression space 4 Rotation prevention member 7 Slewing bearing 8 crankshaft 9 Eccentric part 10 Inhalation port 11 Discharge port 11a, 11c, 11e, 11g Exit expansion part 11b central part 11d, 11f, 11h, 11i, 11m Entrance expansion part 12 airtight container 13 Internal space 14 Compression mechanism 15 Inhalation tube 16 discharge pipe 17 Electric motor 18 Stator 19 rotor 20 bearings 21 Bearing member 22 Positive displacement pump 23 Ball Bearing 24 Support member 50 discharge valve 51 valve clamp 60 scroll compressor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshiyuki Nigami             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Kiyoshi Sawai             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 3H029 AA02 AA14 AB03 BB43 CC15                       CC25 CC54                 3H039 AA03 AA06 AA12 BB28 CC29                       CC30

Claims (5)

[Claims] 1. A fixed scroll and an orbiting scroll are meshed with each other to form a compression space, and a continuous volume change caused by the orbiting motion of the orbiting scroll sucks in and compresses the fluid, and the compressed fluid is converted into the compressed fluid. A scroll compressor for discharging from a discharge port provided in a fixed scroll, characterized in that an inlet expansion portion having a passage cross-sectional area larger than that of a central portion is formed at the fluid inlet side of the discharge port. Machine. 2. The scroll compressor according to claim 1, wherein the enlarged inlet portion has a conical shape. 3. The outflow side of the fluid of the discharge port,
The scroll compressor according to claim 1, wherein an outlet enlarged portion having a passage cross-sectional area larger than that of the central portion is formed, and the outlet enlarged portion has a conical shape. 4. The outlet side of the fluid of the discharge port,
The scroll compressor according to claim 1, wherein an outlet expansion portion having a passage sectional area larger than that of a central portion is formed, and a discharge valve for preventing backflow to the discharge port is provided in the outlet expansion portion. Machine. 5. The scroll compressor according to claim 1, wherein carbon dioxide is used as the fluid and compressed to a critical pressure.