KR20130094650A - Vane rotary compressor - Google Patents

Abstract

PURPOSE: A vane rotary compressor is provided to prevent fluid such as a refrigerant from being supplied at the pressure which is higher than required by forming multiple discharge holes on a rear cover. CONSTITUTION: A vane rotary compressor includes a hollow-shaped cylinder (200), a rotor (300), multiple vanes (400), a front cover, a rear cover, and a pair of heads. The rotor is installed in a hollow, and rotated by receiving the power of a driving source. The multiple vanes appear from the outer circumferential surface of the rotor toward the inner circumferential surface of the cylinder, and partition a compression chamber (210). The front cover is combined with the front end of the cylinder. The rear cover is combined with the rear end of the cylinder. The pair of heads is combined with the outsides of the front cover and the rear cover respectively to be mutually faced. Multiple discharge holes (630), which are connected to the compression chamber of the cylinder, are separated from each other on one side of the rear cover, and formed in the axial direction.

Description

{VANE ROTARY COMPRESSOR}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a vane rotary compressor in which a fluid such as a refrigerant is compressed while a volume of a compression chamber is reduced during rotation of a rotor, and more particularly to a vane rotary compressor in which a plurality of discharge ports are formed in a rear cover, To a vane rotary compressor.

The vane rotary compressor is used in an air conditioner and the like and compresses a fluid such as a refrigerant and supplies it to the outside.

FIG. 1 is a sectional view schematically showing a conventional vane rotary compressor disclosed in Japanese Patent Laid-Open No. 2010-31759 (Patent Document 1), and FIG. 2 is a sectional view taken along line A-A of FIG.

1, a conventional vane rotary compressor 10 has a housing H constituted by a rear housing 11 and a front housing 12 as an outer appearance. Inside the rear housing 11, Of the cylinder 13 is accommodated.

At this time, the inner peripheral surface of the cylinder 13 has an elliptical cross-sectional shape as shown in Fig.

A front cover 14 is coupled to the front of the cylinder 13 and a rear cover 15 is coupled to the rear of the cylinder 13. In the rear housing 15, A discharge space Da is formed between the inner circumferential surface of the rear housing 11 and the front cover 14 and the rear cover 15 facing each other.

A rotary shaft 17 is installed in the front cover 14 and the rear cover 15 to be rotatable through the cylinder 13 and a cylindrical rotor 18 is coupled to the rotary shaft 17, And rotates in the cylinder 13 together with the rotary shaft 17 during rotation.

At this time, as shown in Figure 2, the outer circumferential surface of the rotor 18, a plurality of slots (18a) are radially formed, each of the slots (18a) is a vane 20 is slidably received, the slot ( Lubricating oil is supplied in 18a).

When the rotor 18 is rotated by the rotation of the rotary shaft 17, the tip of the vane 20 protrudes outward of the slot 18a and is brought into close contact with the inner peripheral surface of the cylinder 13, An inner circumferential surface of the cylinder 13 and a pair of vanes 20 adjacent to each other; an opposing face 14a of the front cover 14 opposed to the cylinder 13; A plurality of compartments 21 are formed.

Here, in the case of the vane rotary compressor, the stroke in which the volume of the compression chamber 21 is enlarged in accordance with the rotation direction of the rotor 18 is the suction stroke, and the stroke in which the volume of the compression chamber 21 is reduced is the compression stroke.

In addition, as shown in FIG. 1, a suction port 24 is formed at an upper portion of the front housing 12, and a suction space Sa communicating with the suction port 24 is formed inside the front housing 12. Is formed.

The front cover 14 is provided with a suction port 14b communicating with the suction space Sa, and a suction passage 13b communicating with the suction port 14b is formed through the axial direction of the cylinder 13.

2, discharge chambers 13d recessed inwardly are formed on both sides of the outer circumferential surface of the cylinder 13, and the pair of discharge chambers 13d is compressed by the discharge holes 13a. In communication with 21, a part of the discharge space Da is formed.

The rear housing 11 is formed with a high-pressure chamber 30 which is partitioned by the rear cover 15 and into which compressed refrigerant flows. That is, the inside of the rear housing 11 is partitioned into the discharge space Da and the high-pressure chamber 30 by the rear cover 15. At this time, discharge ports 15e communicating with the high pressure chamber 30 are formed in the pair of discharge chambers 13d, respectively.

Therefore, when the rotor 18 and the vane 20 are rotated during the rotation of the rotary shaft 17, the refrigerant is sucked into the respective compression chambers 21 from the suction space Sa through the suction port 14b and the suction passage 13b, The refrigerant compressed in accordance with the volume reduction of the compression chamber 21 is discharged to the discharge chamber 13d through the discharge hole 13a and flows into the high pressure chamber 30 through the discharge hole 15e, 31).

Reference numeral 40 denotes an oil separator for separating the lubricating oil from the compressed refrigerant introduced into the high-pressure chamber.

2, the discharge hole 13a is formed adjacent to the end point of the compression stroke in which the inner circumferential surface of the cylinder 13 abuts the outer circumferential surface of the rotor 18, and the discharge hole 13a And is formed radially through the outer circumferential surface of the cylinder 13.

However, since the compressed fluid is discharged through the discharge hole 13a only in the last stage of the compression stroke, it is always compressed to a considerably high pressure and supplied to the outside. As a result, the power consumption is increased due to the increase in the flow resistance, It becomes one factor to bring about.

In addition, since the discharge hole 13a is formed radially through the outer circumferential surface of the cylinder 13, the compressed fluid discharged to the outside of the cylinder 13 through the discharge hole 13a is guided to the discharge port 31 The outer surface of the cylinder 13 is once again wrapped around the cylinder 13 by the rear housing 11. In this case, the package is disadvantageous in that the weight, manufacturing cost, and manufacturing time are increased.

Patent Document 1: JP-A-2010-031759 (Feb. 12, 2010)

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the problems as described above, and one embodiment of the present invention is to provide a rear cover having a plurality of discharge holes formed in the axial direction so as to prevent a fluid, such as a refrigerant, And it is an object of the present invention to provide a vane rotary compressor capable of reducing the size of a package by eliminating a housing outside the cylinder and reducing weight, manufacturing cost, and manufacturing time.

According to a preferred embodiment of the present invention, there is provided a centrifugal compressor comprising: a hollow cylinder; a rotor installed in the hollow and receiving rotation of the driving source to rotate; A front cover coupled to a front end of the cylinder, a rear cover coupled to a rear end of the cylinder, and a pair of heads coupled to the outside of the front cover and the rear cover, In the vane rotary compressor, a plurality of discharge holes communicating with the compression chambers of the cylinders are formed on one side of the rear cover so as to be spaced apart from each other and to be axially penetrated.

Preferably, the plurality of discharge holes are formed in a section which is separated from the inner circumferential surface of the cylinder by 120 degrees in a direction opposite to the direction of compression and rotation of the rotor at a position where the inner peripheral surface of the cylinder abuts against the outer circumferential surface of the rotor.

Further, grooves are preferably formed on one side or both sides of the discharge hole to increase the discharge flow rate.

At this time, it is preferable that grooves are formed opposite to each other in a pair of adjacent discharge holes.

According to the vane rotary compressor of the preferred embodiment of the present invention, since the discharge hole communicating with the compression chamber of the cylinder is formed through the rear cover in the axial direction, no separate housing for covering the outer side of the conventional cylinder is required, Accordingly, it is possible to reduce the size and weight of the package, and reduce the manufacturing cost and production time.

When a fluid such as a refrigerant is compressed to a predetermined pressure in the compression chamber, the rear cover is immediately discharged through the discharge hole without continuing to the compression end point. Therefore, It is possible to reduce the flow resistance and to reduce the required power and fuel consumption.

In addition, there is an effect that the discharge flow rate is increased by forming a groove in the discharge port.

1 is a cross-sectional view schematically showing a conventional vane rotary compressor.
2 is a sectional view taken along the line AA in Fig.
3 is a cross-sectional view of a vane rotary compressor in accordance with one embodiment of the present invention.
4 is a sectional view taken along line BB of Fig.
5 is an exploded perspective view of a cylinder and a cover according to an embodiment of the present invention.
6 is a front view showing a rear cover having a discharge hole according to another embodiment of the present invention.

Hereinafter, preferred embodiments of a vane rotary compressor according to an embodiment of the present invention will be described with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

In addition, the following embodiments are not intended to limit the scope of the present invention, but merely as exemplifications of the constituent elements set forth in the claims of the present invention, and are included in technical ideas throughout the specification of the present invention, Embodiments that include components replaceable as equivalents in the elements may be included within the scope of the present invention.

Example

3 is a cross-sectional view of a vane rotary compressor according to an embodiment of the present invention.

3, a vane rotary compressor 100 according to an embodiment of the present invention includes a cylinder 200 having a hollow shape, a cylinder 200 installed in the hollow of the cylinder 200, A plurality of vanes 400 for separating the compression chamber 210 (see FIG. 4) from the outer circumferential surface of the rotor 300 in the direction of the inner circumferential surface of the cylinder 200, A rear cover 600 coupled to the rear end of the cylinder 200 and a pair of heads (not shown) coupled to the outside of the front cover 500 and the rear cover 600, 700,800).

Here, the rotor 300 is coupled to a shaft 900 connected to a clutch (not shown) driven by a driving motor (not shown) or an engine belt (not shown), and rotates together with the shaft 900.

A pair of covers 500 and 600 are coupled to both ends of the cylinder 200. A front cover 500 is coupled to the front end of the cylinder 200 and a rear cover 600 is coupled to the rear end of the cylinder 200. [ .

5) are formed in the center of the front cover 500 and the rear cover 600 so that the shaft 900 can be inserted through the through holes 510 and 610, And support bearings 511 and 611 for supporting the support shaft 900, respectively.

A vane 400 protrudes from the outer circumferential surface of the rotor 300 toward the inner circumferential surface of the cylinder 200 so that the tip end of the vane 400 is supported by the inner circumferential surface of the cylinder 200. The outer circumferential surface of the rotor 300 and the inner circumferential surface of the cylinder 200 The facing surfaces of the pair of vanes 400 adjacent to each other and the opposing surfaces of the front cover 500 and the rear cover 600 with respect to the cylinder 200 define one space, The space constitutes the compression chamber 210.

At this time, the front cover 500 and the rear cover 600 seal the both openings of the hollow of the cylinder 200 to prevent the fluid in the compression chamber 210 from leaking to the outside, and thus the front cover 500 and the cylinder 200 and the sealing member 520 (see FIG. 5) are interposed between the cylinder 200 and the rear cover 600 so as to prevent the radial leakage of the compressed fluid in the cylinder 200 desirable.

The front head 700 is coupled to the outside of the front cover 500 and the rear head 800 is coupled to the outside of the rear cover 600 with respect to the cylinder 200.

3, the front head 700, the front cover 500, the cylinder 200, the rear cover 600, and the rear head 800 are coupled together by a plurality of bolt screws 910, At this time, reference numeral 920, which is not shown in FIG. 3, is a supporting member for supporting the shaft 900.

5) is formed at one side of the cylinder 200 so as to communicate with the hollow and the rear cover 600 is spaced apart along the inner circumferential surface of the cylinder 200 so as to communicate with the hollow of the cylinder 200, The refrigerant flowing into the hollow of the cylinder 200 through the suction port 220 is compressed in the compression chamber 210 and is then discharged to the high pressure state And is supplied to the outside through the discharge hole 630.

Although the inner circumferential surface of the cylinder 200 has an involute curve and the cantilevered vane 400 is expanded or folded on the outer circumferential surface of the rotor 300 in the present embodiment, The present invention can be applied to a vane rotary compressor having various structures according to the user's choice.

For example, as shown in FIG. 3, the rotor 18 is installed in the cylinder 13 having an elliptical hollow, and the slots 18a are radially formed along the outer circumferential surface of the rotor 18, and each slot Inserting the vane 20 into the 18a allows the vane 20 to slide in the direction of the inner circumferential surface of the cylinder 13 from the slot 18a by the pressure of the fluid. Of course, the rotor may be installed to be eccentric in the cylinder.

4 is a sectional view taken along the line B-B in Fig.

4, a plurality of vanes 400 are provided circumferentially spaced apart from each other along the outer circumferential surface of the rotor 300, so that the hollow of the cylinder 200 is partitioned into a plurality of compression chambers 210. In this embodiment, do.

The fluid such as the refrigerant introduced into the hollow of the cylinder 200 through the suction port 220 is confined in the compression chamber 210 and is compressed as the volume of the compression chamber 210 decreases during rotation of the rotor 300, The inner circumferential surface of the weft cylinder 200 is formed in the form of an involute curve in which the diameter gradually decreases from the inlet port 220 toward the outlet port 630.

That is, the diameter of the inner circumferential surface of the cylinder 200 gradually decreases from the inlet port 220 to the outlet hole 630 along the compression and rotation direction of the rotor 300, and between the inner circumferential surface of the cylinder 200 and the outer circumferential surface of the rotor 300 The volume of the compression chamber 210 is reduced as the interval is gradually narrowed.

At this time, the rotor 300 is installed in the hollow of the cylinder 200 so that the inner circumferential surface of the cylinder 200 and the outer circumferential surface of the rotor 300 are concentric with each other. That is, the center of the start point and the end point of the involute curve drawn along the inner circumferential surface of the cylinder 200 is the same as the center of the rotor 300.

The vane 400 is hinged to one side of the outer circumferential surface of the rotor 300 to form a cantilever. The vane 400 includes a hinge portion 410 hinged to one side of the outer circumferential surface of the rotor 300 and a wing portion 420 extending from the hinge portion 410.

The hinge portion 410 of the vane 400 is hinged to one side of the outer circumferential surface of the rotor 300. The hinge portion 410 is hinged to one side of the outer circumferential surface of the rotor 300. For example, The hinge unit 410 can be rotatably inserted into the hinge unit 310. [ At this time, it is preferable that the hinge portion 410 is not separated in the radial direction of the rotor 300.

The wing portion 420 of the vane 400 extends to one side of the hinge portion 410 and the outer surface of the wing portion 420 facing the inner circumferential surface of the cylinder 200 corresponds to the shape of the outer circumferential surface of the rotor 300 As shown in FIG.

This is to allow the outer surface of the wing portion 420 of the vane 400 to contact the inner circumferential surface of the cylinder 200 at a point where the outer circumferential surface of the rotor 300 and the inner circumferential surface of the cylinder 200 are in contact with each other, A plurality of receiving grooves 320 for accommodating the vanes 400 of the vanes 400 are formed in the circumferential direction corresponding to the number of the vanes 400. [

The outer circumferential surface of the wing portion 420 and the outer circumferential surface of the rotor 300 are curved surfaces having the same curvature when the wing portion 420 of the vane 400 is completely received in the receiving groove 320. At this time, As shown in FIG. That is, the bottom surface shape of the receiving groove 320 corresponds to the inner surface shape of the wing portion 420, and the depth of the receiving groove 320 corresponds to the thickness of the wing portion 420.

Since the hinge portion 410 is hinged to the outer circumferential surface of the rotor 300 so as to be rotatable and hinge-coupled to the vane 400, the centrifugal force generated when the rotor 300 rotates and the reaction force from the fluid, Rotates to the outside of the rotor 300 around the hinge portion 410 and unfolds.

The distal end of the opened wing portion 420 is closely supported on the inner circumferential surface of the cylinder 200 to seal the compression chamber 210 and move along the inner circumferential surface of the cylinder 200 together with the rotation of the rotor 300.

 At this time, the gap between the inner circumferential surface of the cylinder 200 and the outer circumferential surface of the rotor 300 is narrowed from the inlet port 220 toward the discharge hole 630, and the angle of the wing portion 420 of the vane 400 gradually decreases The compression of the fluid such as the refrigerant in the compression chamber 210 progresses while the volume of the compression chamber 210 decreases. The vane 400 is completely folded and received in the receiving groove 320 of the rotor 300 at a position where the outer peripheral surface of the rotor 300 and the inner peripheral surface of the cylinder 200 are in contact with each other.

That is, the compression stroke ends at the compression end point C _e where the outer circumferential surface of the rotor 300 contacts the inner circumferential surface of the cylinder 200, and the vane rotary compressor 100 according to an embodiment of the present invention includes a compression end point C _e) is compressed in a direction opposite to the rotational direction of the plurality of discharge holes (630 in the rear cover 600 at 120 ° intervals in the angular range (S) of the rotor 300) are formed in.

The plurality of discharge holes 630 are spaced apart from each other along the inner circumferential surface of the cylinder 200 so as to communicate with the compression chamber 210. Each discharge hole 630 is formed at one side of the rear cover 600 (Not shown) that opens and closes the valve. When the pressure of the fluid such as the refrigerant is lower than a predetermined pressure (hereinafter, referred to as 'discharge pressure'), the valve is closed, and the pressure of the fluid such as refrigerant reaches the discharge pressure The valve is opened so that a fluid such as compressed refrigerant can be discharged to the outside of the cylinder 200 through the discharge hole 630. [

At this time, the diameter and the number of the discharge holes 630 and the discharge pressure can be appropriately selected as needed, and the section S in which the plurality of discharge holes 630 are formed is moved from the compression end point C _e to the compression rotation direction The range of the angle of 120 deg. In the reverse direction is that the fluid such as the refrigerant in the compression chamber is lower than the pressure actually required outside the above range.

A plurality of discharge holes 630 formed in the axial direction of the rear cover 600 are spaced apart from each other along the inner circumferential surface of the cylinder 200 in a direction opposite to the direction of compression and rotation from the compression end point C _e When a fluid such as a refrigerant in the compression chamber 210 reaches the discharge pressure during the compression stroke, the fluid is discharged to the outside of the cylinder 200 through one or more discharge holes 630 which communicate with each other.

For example, in the embodiment shown in FIG. 4, a fluid such as a refrigerant trapped in the compression chamber 210, which is defined by a pair of adjacent vanes 400, is supplied to the rotor 300 along the inner circumferential surface of the cylinder 200 The refrigerant passes through the path from the first discharge hole 631 to the fifth discharge hole 635 in the process of flowing in the compression rotation direction and is compressed by the volume reduction of the compression chamber 210.

When the pressure of the compression chamber 210 reaches the discharge pressure while the fluid such as the refrigerant passes the path from the first discharge hole 631 to the fifth discharge hole 635, The discharge hole 630 is opened and a fluid such as a refrigerant compressed to the outside of the cylinder 200 is discharged.

That is, if the fluid such as the refrigerant in the compression chamber 210 is not continuously compressed until the compression stroke is completed as in the conventional case, and the compression is continued to the preset discharge pressure, .

For example, when a fluid such as a refrigerant can not be compressed to the discharge pressure while passing through the first discharge hole 631 and the second discharge hole 632, the first discharge hole 631 and the second discharge hole 632 are closed When the pressure of the fluid such as the refrigerant reaches the discharge pressure when passing through the third discharge hole 633, the opening and closing valve is opened by this pressure and the fluid such as the refrigerant is discharged through the third discharge hole 633 And is discharged. This is also true when the partial pressures of the fluids such as the refrigerant which are caught in the respective discharge holes 630 in the same compression chamber 210 are different from each other and when the partial pressure reaches the discharge pressure, 630).

Here, the discharge pressure required for opening the on-off valve can be appropriately set on the basis of the final pressure of the fluid such as the refrigerant to be obtained through the compressor, The flow path resistance can be reduced, and the required power can be saved.

In addition, since the discharge hole 630 is formed in the rear cover 600 in the axial direction, a separate housing 11 (see FIG. 2) for covering the outer circumferential surface of the cylinder 200 is unnecessary, The entire package of the package 100 can be shrunk.

FIG. 5 is an exploded perspective view of a cylinder and a cover according to an embodiment of the present invention, and the illustration of the rotor is omitted for convenience of explanation.

As shown in FIG. 5, the cylinder 200 is opened at both sides and has a hollow inside, and a suction port 220 is formed at one side thereof.

At this time, a rotor 300 having a plurality of vanes 400 is rotatably installed in the hollow of the cylinder 200, the hollow is divided into a plurality of compression chambers 210 by a plurality of vanes 400, The front cover 500 and the rear cover 600 are coupled to the front and rear ends of the cylinder 200 to seal the chamber 210, respectively.

A plurality of discharge holes 630 are formed in one side of the rear cover 600 in the axial direction and each of the discharge holes 630 is communicated with the compression chamber 210 of the cylinder 200.

Accordingly, the refrigerant introduced into the hollow of the cylinder 200 through the suction port 220 is compressed in the compression chamber 210, and then supplied to the outside through the discharge hole 630 in a state of high pressure.

5, a groove 640 may be formed at one side of the discharge hole 630, which is formed through the bottom surface of the rear cover 600, at a low level.

This groove 640 is for increasing the discharge flow rate discharged through the discharge hole 630. When the fluid such as the refrigerant of the compression chamber 210 reaches the discharge pressure, Such as a refrigerant, to be discharged through the discharge hole 630 or the discharge hole 630 that has not yet been communicated.

5, when the compression chamber 210 in which the pressure of the fluid such as the refrigerant reaches the discharge pressure has already passed through the sixth discharge hole 636, the compression chamber 210 is still in the sixth discharge The fluid such as the refrigerant can flow and discharge to the sixth discharge hole 636 through the groove 640 of the sixth discharge hole 636, if it has not passed through the groove 640 of the hole 636. If the groove 640 of the seventh discharge hole 637 is connected to the compression chamber 210 even when the compression chamber 210 has not yet reached the seventh discharge hole 637, And can be discharged to the seventh discharge hole 637 through the groove 640 of the discharge hole 637 and discharged.

That is, even when a pair of discharge holes 630 adjacent to each other are not in direct contact with the compression chamber 210, the fluid such as the refrigerant that has reached the discharge pressure is discharged through the grooves 640 Is communicated with the compression chamber 210, the refrigerant flows to the discharge hole 630 through the groove 640 and is discharged, thereby increasing the discharge flow rate through the discharge hole 630.

The groove 640 is preferably formed in the circumferential direction along the inner circumferential surface of the cylinder 200 from one side of the discharge hole 630 so as to communicate with the compression chamber 210 near the discharge hole 630, And is preferably formed in a curved shape corresponding to the inner circumferential surface of the cylinder 200.

5, a fluid such as a coolant located between the pair of discharge holes 636 and 637 may be discharged through one or both of the pair of discharge holes 636 and 637 It is preferable that the grooves 640 are formed so that one end of the groove 640 faces each other.

6 is a front view showing a rear cover having a discharge hole according to another embodiment of the present invention.

5 shows an example in which a groove 640 is formed on one side of the discharge hole 630. In another embodiment, the grooves 640 are formed on both sides of the discharge hole 630 Of course it is possible.

FIG. 6 illustrates another embodiment of the present invention. In this embodiment, the flow of a fluid such as a refrigerant can be discharged to the discharge hole 630 through the first groove 641 after passing through the discharge hole 630, 630 to the discharge hole 630 through the second groove 642 and discharged.

The first groove 641 and the second groove 642 are connected to the compression chamber 210 near the discharge hole 630 in the circumferential direction along the inner circumferential surface of the cylinder 200 from both sides of the discharge hole 630 And more preferably, it is formed in a curved shape corresponding to the inner circumferential surface of the cylinder 200.

Here, it is needless to say that the opening / closing valve can be opened and discharged only when the pressure of the fluid such as the refrigerant flowing into the discharge hole 630 through the first groove 641 or the second groove 642 reaches the discharge pressure The first grooves 641 and the second grooves 642 cover the relatively wide range of the compression chambers 210, so that the discharge flow rate is increased.

100: vane rotary compressor 200: cylinder
210: compression chamber 220: inlet
300: rotor 400: vane
500: Front cover 600: Rear cover
630: Discharge hole 640: Groove
700: front head 800: rear head
900: Shaft

Claims (4)

A rotor 300 installed in the hollow and rotated by receiving the power of the driving source and a rotor 300 rotatably supported on the outer circumferential surface of the rotor 300 in the inner circumferential surface of the cylinder 200, A front cover 500 coupled to a front end of the cylinder 200 and a rear cover 600 coupled to a rear end of the cylinder 200; And a pair of heads (700, 800) respectively coupled to the outside of the rear cover (600) so as to oppose each other, the vane rotary compressor comprising:
The vane rotary compressor, characterized in that the plurality of discharge holes (630) communicating with the compression chamber (210) of the cylinder (200) is formed in the axial direction spaced apart from each other on one side of the rear cover (600).
[6] The apparatus according to claim 1, wherein the plurality of discharge holes (630)
Is formed in a section (S) that is separated by 120 degrees in a direction opposite to the compression rotation direction of the rotor (300) at a point where the inner circumferential surface of the cylinder (200) abuts the outer circumferential surface of the rotor (300).
The method according to claim 1,
And a groove (640) is formed at one side or both sides of the discharge hole (630) for increasing a discharge flow rate.
The method according to claim 3,
And a groove (640) is formed opposite to each other in a pair of adjacent discharge holes (630).

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