KR20060048898A - Variable capacity gas compressor - Google Patents

Abstract

In a variable displacement gas compressor, the outflow amount is precisely matched to the desired amount in the selective outflow of a part of the gas in the compression stroke.

As the iron portion 81 of the spool valve 80 (bypass valve) withdraws from the bypass hole opening 71 opened to the inside of the cylinder 40 (the compression chamber 48 (C)), the volume is reduced. In the compressor 100 (capacity variable type gas compressor) which changes efficiency, the spool valve opening position where the iron portion 81 withdraws from the bypass hole opening 71 to the valve accommodation chamber 72 is iron. (I) Calculated by the product of the distance h between the front end face 82 of the part 81 and the inner wall surface 72a of the valve accommodation chamber 72 and the circumferential length of the iron part 81; The flow path area S2 is set to be at least twice the opening area S1 of the bypass hole opening 71.

Variable displacement, gas compressor, vane rotary, opening, bypass hole

Description

Variable capacity gas compressor

1 is a cross-sectional view showing a vane rotary type compressor which is one embodiment of a variable displacement gas compressor according to the present invention.

2 is a cross-sectional view taken along the line A-A of the compressor shown in FIG.

FIG. 3 is a view for explaining the variable capacity mechanism of the compressor shown in FIG. 1, in which (a) and (b) show a maximum capacity state, and (c) and (d) show a state where the capacity is reduced.

It is a schematic diagram which shows the area of an opening area and an imaginary surface.

FIG. 5 is a schematic diagram illustrating a flow path area when flowing into the bypass hole opening portion, a flow path area when entering the valve accommodation chamber, and an opening ratio; FIG.

Fig. 6 is a view for explaining a variable capacity mechanism of a conventional compressor, in which (a) and (b) show a maximum capacity state, and (c) and (d) show a state where the capacity is reduced.

<Explanation of symbols for the main parts of the drawings>

10 housing

11 cases

12 front head

13 suction chamber

15 discharge chamber

20 front side block

28 section

30 rear side block

40 cylinders

48 compression chamber

Compression chamber corresponding to 48 (C) compression stroke

49a inner circumference

50 rotor

51 axis of rotation

70 bypass passage

71 bypass hole opening

72 valve accommodation room

73 Communication Department

80 Spool Valve (Bypass Valve)

81 Iron

82 tip

83 Outer surface

84 seating surface

100 compressors (capacity variable gas compressors)

G Refrigerant Gas (Gas)

R freezer oil

Opening area of S1 bypass hole opening

Area (Euro Area) of S2 Virtual Surface

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement gas compressor, and more particularly, to an improvement in the operation of a bypass valve that outflows a portion of gas in a compression stroke.

BACKGROUND ART Conventionally, a gas compressor for compressing a refrigerant gas and circulating a refrigerant gas in a system has been used in an air conditioning system (hereinafter referred to as an "air conditioning system"). The gas compressor also has a variable displacement type that allows the discharge amount to be varied when discharging the compressed gas to the outside.

For example, in a variable displacement compressor having a compressor body of a general vane rotary type inside the housing, the compressor body has a rotor that rotates integrally with the rotating shaft, and a cross-sectional contour surrounding the outer side of the rotor outer circumferential surface is substantially elliptical. A cylinder having an inner circumferential surface, and a plurality of plate-shaped vanes provided on the rotor at equal angle intervals around the axis of rotation, which project from the outer circumferential surface of the rotor and abutting the inner circumferential surface of the cylinder, and from both end faces of the rotor, respectively. It has two side blocks (front side block and rear side block) arranged to sandwich the rotor and the cylinder therebetween, and in accordance with the rotation of the rotation axis, the two side blocks, the rotor, the cylinder, and the rotor in the direction of rotation of each other By repeating the increase and decrease of the volume of the compression chamber partitioned by two front and rear vanes, It is configured to discharge the compressed refrigerant gas in the suction chamber.

Then, the portion of the front side block constituting the compression chamber corresponding to the compression stroke of the refrigerant gas flows the refrigerant gas inside the compression chamber corresponding to the compression stroke into the space relatively lower than the internal pressure of the compression chamber. At the same time as the passage passage is formed, a spool valve (bypass valve) for opening and closing the bypass passage is provided. By opening the spool valve, a portion of the refrigerant gas flows out of the compression chamber in the compression stroke into the low pressure space, The capacity is reduced, which results in varying the amount of refrigerant gas discharged from the compression chamber.

Here, the detailed structures of the bypass passage and the spool valve will be described with reference to FIG.

First, the bypass passage 70 is located inside surrounded by the cylinder 40, the bypass hole opening 71 opened at the end face 28 of the front side block 20, and the bypass hole opening 71 ) And a communication unit 73 which communicates with the spool valve 80 so that the spool valve 80 is slidably and from the valve accommodation chamber 72 to the suction chamber 13, which is a low pressure space.

The spool valve 80 accommodated in the valve accommodating chamber 72 enters the bypass hole opening 71 and has an outer circumferential surface 83 which slides against the circumferential surface 71 a of the bypass hole opening 71. ) 81 and the inside of the valve receiving chamber 72 adjacent to the iron portion 81 and substantially perpendicular to the outer circumferential surface 83 and continuous to the bypass hole opening 71. It has the seating surface part 84 which abuts on the wall surface 72a, and can move forward and backward along the valve accommodation chamber 72. As shown in FIG.

In the state where the back pressure is loaded on the spool valve 80 and the iron portion 81 of the spool valve 80 enters the bypass hole opening 71 (FIG. 6 (a)), the back pressure is applied by the back pressure. The seating surface portion 84 of the spool valve 80 is pressed against the valve receiving chamber inner wall surface 72a as the seat surface of the valve seat, and the bypass passage 70 is closed.

Therefore, a high-pressure refrigerant is supplied from the compression chamber 48 (hereinafter, generally referred to as 48 when referring to the compression chamber, and 48 (C) when referring to the compression chamber corresponding to the compression stroke). The gas G does not flow out into the suction chamber 13, and as shown in FIG. 6B, the gas G is compressed at the same timing (rotation angle position of the vane) as when the bypass passage 70 is not formed. The administration begins.

In the state where the seating surface portion 84 of the spool valve 80 is press-contacted to the valve storage chamber inner wall surface 72a as the seat surface of the valve seat (the bypass passage 70 is closed), the spool valve ( The front end face 82 of the convex portion 81 of the 80 is formed to be substantially the same as the end face 28 of the front side block 20.

On the other hand, in the state where the back pressure is not loaded on the spool valve 80, the spool valve 80 is caused by the internal pressure of the compression chamber 48 to be loaded to the front end face 82 of the iron portion 81, The convex portion 81 slides inside the valve accommodating chamber 72 so as to withdraw from the bypass hole opening 71 (FIG. 6C).

At this time, the seating surface portion 84 of the spool valve 80 is separated from the valve chamber inner wall surface 72a as the seat surface of the valve seat, and the iron portion 81 has a front end surface 82 of which the valve portion is accommodated. Since it retreats from the chamber inner wall surface 72a and completely withdraws from the bypass hole opening 71, the refrigerant gas G flowing into the bypass hole opening 71 from the compression chamber 48 is discharged from the spool valve 80. In the gap between the front end surface 82 and the inner wall surface 72a of the valve receiving chamber 72, that is, the trajectory of the outer circumferential surface 83 of the iron portion 81 withdrawn from the bypass hole opening 71, the valve It flows into the valve accommodation chamber 72 through the virtual surface (area S2) of the cylindrical peripheral surface shape corresponding to the part inside the valve accommodation chamber 72 rather than the inner wall surface 72a of the accommodation chamber 72. And the refrigerant gas G flows out from the valve accommodation chamber 72 to the suction chamber 13 through the communication part 73. As shown in FIG.

In this case, as shown in Fig. 6 (d), until the vanes 58 pass through the bypass hole opening 71, they are in a position that is formally defined as a compression stroke based on, for example, the rotational position. Even in the compression chamber 48 (C), since the refrigerant gas G therein continues to flow through the bypass passage 70 into the suction chamber 13, the compression stroke is not actually started, and the vane ( The time point when 58 passes through the bypass hole opening 71 becomes the actual start of the compression stroke.

Therefore, opening the bypass passage 70 substantially delays the start timing of the compression stroke, thereby changing the capacity of the compression chamber 48 (C) at the start of compression.

[Patent Document 1] Japanese Patent Application No. 2004-44398 (Unpublished)

By the way, the above-described variable displacement compressor 100 retracts the spool valve 80 to open the bypass passage 70, and the refrigerant gas G is moved from the bypass hole opening 71 to the valve accommodation chamber 72. The flow path passing when the flow inflows) becomes the above-described virtual surface (surface of a cylindrical circumferential surface represented by the area S2) as shown in the schematic diagram of FIG. 4, and the area S2 of this virtual surface is bypassed. The displacement amount of the spool valve 80 (the displacement amount until the iron portion 81 withdraws from the bypass hole opening 71 so that the flow path area S1 of the hole opening 71 is almost the same) and the iron portion The sum total of the distance h from the front end surface 82 of the part 81 to the inner wall surface 72a of the valve accommodation chamber 72 is set.

As shown in FIG. 4, this is between the inlet end (cross section of the front side block) of the bypass hole opening 71 and the outlet end (between the front end face 82 of the spool valve 80 and the front end block 28 of the front side block). By making the flow path area S of the refrigerant gas G constant over a gap of the gap, the refrigerant gas G can be smoothly flowed out.

However, since the refrigerant gas G flowing into the bypass hole opening 71 and passing through the bypass hole opening 71 tries to proceed in the same direction as the bypass hole opening 71 extends, it retreats in that direction. It comes in contact with the front end face 82 of the iron part 81 of the spool valve 80 which exists, and then it is sprayed to the periphery along this front end face 82, and passes through the above-mentioned virtual surface, and it is a valve accommodation chamber. Flow into (72).

Therefore, the inflow portion from the bypass hole opening 71 to the valve accommodation chamber 72 acts as a flow resistance to the refrigerant gas G, so as to ensure the flow rate of the bypass passage 70 by a desired flow rate. It was difficult. That is, the amount of discharged refrigerant gas (volume efficiency) from the compressor main body could not be varied as desired.

In addition, such a problem may not only occur in the vane rotary type variable gas compressor, but also in the scroll type or the inclined plate reciprocating type.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a variable displacement gas compressor capable of precisely matching the outflow amount to a desired amount in selectively discharging a part of the gas in the compression stroke.

The variable-capacity gas compressor according to claim 1 of the present invention has a compressor main body which compresses the sucked gas inside a cylinder and discharges the compressed gas, and the compressor main body has a part of the gas in the compression stroke. A bypass passage for selectively flowing out into the low pressure space is formed, and a bypass valve for opening and closing the bypass passage is provided, and the variable displacement gas compressor can change the amount of discharged gas by opening and closing the bypass valve. The bypass passage may include: a bypass hole opening opened to the inside of the cylinder; a valve accommodation chamber continuous with the bypass hole opening; and the bypass valve accommodated; and the valve accommodation chamber from the valve accommodation chamber to the low pressure space. The bypass valve made of a communication unit, the bypass valve accommodated in the valve accommodation chamber, An iron portion having an outer circumferential surface which slides into the bypass hole opening and slides in contact with the circumferential surface of the bypass hole opening, and is adjacent to the iron portion and substantially perpendicular to the outer circumferential surface. The opening position of the bypass valve having a seating surface portion which is in contact with an inner wall surface of the valve accommodation chamber that is continuous to the hole opening portion, wherein the iron portion withdraws from the bypass hole opening portion to the valve accommodation chamber, The path area calculated by the product of the distance between the tip of the part and the inner wall surface and the circumferential length of the iron part is twice or more with respect to the opening area of the bypass hole opening portion on the wall surface of the cylinder. It is characterized by being set.

Although it does not specifically limit about 2 times or more of upper limits, It is set as the range which shows the effect of this invention by design. However, from the viewpoint of making the movable valve as small as possible, the passage area preferably has a value close to twice the ratio of the opening area of the bypass hole opening.

Here, the seating surface is a surface formed in the bypass valve which opposes the inner wall surface of the valve storage chamber as the seat surface of the valve seat and abuts (presses) the inner wall surface to prevent entry of gas.

As the gas to be compressed by the variable-volume gas compressor, for example, a refrigerant gas such as pron gas or carbon dioxide gas can be used, but the present invention is not limited to these refrigerant gases.

The low pressure space may be an external space of the compressor main body, or may be a space corresponding to the suction stroke of the gas (the pressure lower than the space corresponding to the discharge stroke) of the space in the cylinder.

The compressor main body may be of the vane rotary type, scroll type, or inclined plate reciprocating type.

The variable capacity action of the variable displacement gas compressor configured as described above is performed by the following basic operations.

That is, the outer circumferential surface of the convex portion of the bypass valve is formed in a shape almost corresponding to the inner circumferential surface of the bypass hole opening portion. In the closed position of the bypass valve, the iron portion enters the bypass hole opening so that the tip end surface of the iron portion is located in the inner space of the cylinder and is seated adjacent to the iron portion. Bypassing the surface against the inner wall surface of the valve receiving chamber as the seat surface of the valve seat closes the bypass passage, thereby preventing gas from flowing out of the compressed space enclosed by the cylinder through the bypass passage. The amount of gas discharged is the maximum amount.

On the other hand, in the open position of the bypass valve, the iron portion withdraws from the bypass hole opening to the valve storage chamber, and the seating surface of the bypass valve and the inner wall surface (valve seat surface) of the valve storage chamber are separated from each other. Since some of the compressed gas flows out into the low pressure space through the bypass hole opening, the valve accommodating chamber, and the communicating portion, the amount of the gas discharged from the compressor main body becomes a quantity reduced from the maximum amount. Therefore, the amount of discharge gas can be actively changed by opening and closing the bypass valve.

Here, when the bypass valve is in the open position, the passage area of the bypass passage that passes when a part of the compressed gas in the cylinder-enclosed space flows out into the low pressure space is defined as a space enclosed by the cylinder with respect to the bypass hole opening ( Cylinder area corresponding to the trajectory of the circumferential surface of the iron portion retracted from the bypass hole opening portion, which is an opening area S1 of the compression chamber or the like, and flows into the valve accommodation chamber from the bypass hole opening portion. The area of the planar imaginary surface, that is, the product of the distance (D) between the tip of the iron portion withdrawn from the bypass hole opening and the inner wall surface of the valve accommodation chamber, and the circumferential length (L) of the iron portion. The area S2 (= D × L) calculated by this is obtained.

Here, in the conventional variable displacement gas compressor, the area S2 of this virtual surface is set equal to the opening area S1 (S2 = S1), and the area S2 of the virtual surface is thus the opening area S1. ), It can be considered that the flow path of the gas from the bypass hole opening to the valve accommodation chamber will not be narrowed.

However, since the compressed gas flowing into the bypass hole opening and passing through the bypass hole opening proceeds along the direction in which the bypass hole opening extends, the compressed gas reaches the front end surface of the iron portion of the bypass valve retracted in that direction. Then, it disperse | distributes to this periphery along this front end surface, and flows into the valve accommodation chamber through the above-mentioned imaginary surface.

In this way, the gas collided with the front end surface of the convex portion of the bypass valve changes its traveling direction, so that the inflow portion from the bypass hole opening into the valve accommodation chamber acts as a flow path resistance to the gas. It is difficult to ensure the flow rate of the passage passage by the desired flow rate. That is, the amount of discharged gas (volume efficiency) from the compressor main body cannot be varied as desired.

In this regard, in the variable displacement gas compressor according to the present invention, since the area S2 of the virtual surface is set to be two times or more the opening area S1, the compressed gas passing through the bypass hole opening is separated from the bypass hole opening. Even if the direction of travel changes in the inflow portion into the valve storage chamber, the area of the inflow portion, that is, the flow path area is set to be two times or more wider than the opening area S1 of the bypass hole opening, so that the inflow portion becomes the flow path resistance. Difficult to set the flow rate of the bypass passage to the desired amount.

Therefore, the discharge gas amount (volume efficiency) of the compressor main body can be varied as desired.

In addition, although the ratio (referred to the opening ratio) of the area S2 of the imaginary surface with respect to the opening area S1 should just be 200% (2 times) or more, it is preferable that it is 200%. According to the experiments of the present inventors, for example, when the target value of the volume efficiency is set to 30%, it is possible to realize the volume efficiency of 30% as the target value at the aperture ratio 200%, while the aperture ratio is 200% or more. The volumetric efficiency remains almost 30% and hardly changes, and when the opening ratio is 200% or more, it is necessary to secure an unnecessarily large amount of movement of the bypass valve.

On the other hand, if the opening ratio is set to 200%, the expansion of the valve storage chamber space can be minimized. If the opening ratio is about 200%, the size of the bypass valve movement direction without the need to enlarge the space of the valve storage chamber ( It can also be achieved by shortening the length).

In addition, in the variable displacement gas compressor according to claim 2 of the present invention, the variable displacement gas compressor according to claim 1, wherein the compressor main body, a rotor that is integrally rotated with the rotating shaft, and a cylinder surrounding the outside of the outer peripheral surface of the rotor And a plurality of plate-shaped vanes provided at equal angle intervals around the rotation axis, the protrusions protruding from the outer circumferential surface of the rotor and abutting the inner circumferential surface of the cylinder; Two side blocks disposed so as to sandwich the cylinder, and the two side blocks, the rotor, the cylinder, and two vanes which are moved back and forth with each other in a rotational direction of the rotor according to the rotation of the rotary shaft. Compressor body of vane rotary type in which the volume of the compression chamber partitioned by Standing, the bypass hole has an opening being formed in a side block corresponding to the compression stroke to decrease the volume of the compression chamber.

According to the variable displacement gas compressor configured as described above, in the vane rotary type variable gas compressor, the suction hole as a low pressure space is provided in the configuration in which the bypass hole opening is formed in the side block corresponding to the compression stroke in which the volume of the compression chamber is reduced. Since it is arrange | positioned adjacent to this side block, a bypass length can be comprised in short length, without having to comprise a complicated path | route.

According to the variable displacement gas compressor according to the present invention, even if the compressed gas passing through the bypass hole opening is changed in the inflow portion from the bypass hole opening to the valve accommodation chamber, the area of the inflow portion, that is, the flow path area of the gas is increased. Since the opening portion is set to be twice or more wider than the opening area S1 of the passage opening, the inflow portion is less likely to become a flow path resistance, and the flow rate of the bypass passage can be set to a desired amount.

Therefore, the discharge gas amount (volume efficiency) of the compressor main body can be varied as desired.

(Example)

Best Mode for Carrying Out the Invention The best embodiment of the variable displacement gas compressor of the present invention will now be described with reference to the drawings.

1 is a longitudinal sectional view showing a vane rotary compressor 100 as an embodiment of a variable displacement gas compressor according to the present invention, Figure 2 is a cross-sectional view taken along the line A-A of FIG.

The illustrated compressor 100 is a variable displacement compressor 100 having a vane rotary type compressor main body inside the housing 10. The housing 10 includes a case 11 having one end side opened and a housing 11. It consists of the front head 12 which closes one side opening.

A suction port 14 through which the low pressure refrigerant gas G is sucked is formed in the front head 12 constituting the housing 10, and the case 11 discharges the high pressure refrigerant gas G to the outside. The discharge port 16 is formed.

The compressor main body accommodated in the housing 10 includes a rotor 50 which rotates integrally with the rotating shaft 51 and an inner circumferential surface 49a having a substantially elliptical cross-sectional profile surrounding the outer circumferential surface of the rotor 50. The cylinder 40 and the rotor 50 protruding from the outer circumferential surface of the rotor 50, and the protruding end thereof is provided to the rotor 50 at equal angle intervals around the rotating shaft 51, which abuts against the inner circumferential surface 49a of the cylinder 40. The front side block 20 and the rear side fixed to the cylinder 40 so that the rotor 50 and the cylinder 40 may be inserted between the five plate-shaped vanes 58 and the both end surface sides of the rotor 50, respectively. Block 30.

In addition, as the rotation shaft 51 rotates, the two side blocks 20 and 30, the rotor 50, the cylinder 40, and the two vanes 58 and 58 which move back and forth to each other in the rotation directions of the rotor 50. The volume of each compression chamber 48 partitioned by the repetition increases and decreases, thereby compressing and discharging the refrigerant gas G (gas) sucked into each compression chamber 48.

Moreover, the compressor main body is arrange | positioned at the predetermined position in the housing | casing 10 by the one end side of the rotating shaft 51 being axially supported by the front head 12, and the outer peripheral part of the cylinder 40 being supported by the case 11.

In addition, while the compressor main body is accommodated inside the case 11, the discharge chamber 15 is formed by the rear side block 30 and the case 11, while the front side block 20 and the front head 12 are formed. ), The suction chamber 13 is formed, and these suction chambers 13 and the discharge chamber 15 are hermetically separated by a seal member such as an O-ring. Moreover, the cyclone block 60 mentioned later is attached to the rear side block 30. As shown in FIG.

In addition, the lower part of the discharge chamber 15 lubricates / cools / cleans the sliding part of the compressor 100, etc., and at the same time, the refrigerator oil which protrudes the vane 58 mentioned later to the inner peripheral surface 49a of the cylinder 40 direction. (R) (lubricating oil) is stored.

On the other hand, the rotating shaft 51 penetrates the through support hole 23 of the front side block 20, extends to the outside of the front head 12 through the mechanical seal 18, and the power supply unit 90 at the front end thereof. Is attached, and the other end of the rotating shaft 51 is supported by the through support hole 32 of the rear side block 30.

The rotor 50 has five slit-shaped vane grooves 56 radially and at the same time around the center of rotation of the rotor 50 at equal angle intervals, and these vane grooves 56 each have a flat vane 58. ) Is inserted.

Each vane 58 has a cylinder by centrifugal force generated by the rotation of the rotor 50 and hydraulic pressure of the refrigerator oil R applied to the back pressure chamber partitioned by the vane groove 56 and the bottom surface of the vane 58. It protrudes in the direction of the inner peripheral surface 49a of 40, and the protruding tip of this vane 58 is urged in contact with the inner peripheral surface 49a of the cylinder 40. As shown in FIG.

For this reason, the space inside the cylinder 40 is lost by the cylinder 40, the rotor 50, the vanes 58, the front side block 20, and the rear side block 30. Each of these chambers forms a compression chamber 48 that repeats the volume change in accordance with the rotation of the rotor 50.

In addition, the front side block 20 opens a front side suction port for communicating the suction chamber 13 and the compression chamber 48 with the refrigerant gas G flowing into the suction chamber 13 compressed from the front side suction port. Is sucked into the seal 48.

In addition, the rear side suction part may be formed also in the rear side block 30. In the compressor 100 provided with such a rear suction part, a communication hole for communicating the rear suction part and the front suction port is formed in the cylinder 40.

Accordingly, the rear suction part is supplied with the refrigerant gas G sequentially passing through the communication holes of the front suction port and the cylinder 40, and sucks the refrigerant gas G into the compression chamber 48 similarly to the front suction port. It functions as a part to make.

The cyclone block 60 provided on the discharge chamber 15 side of the rear side block 30 includes an oil separator 62 for separating the refrigeration oil R mixed in the refrigerant gas G.

The discharge chamber 44 is formed in the cylinder 40. Moreover, the discharge port 42 which communicates the compression chamber 48 and the discharge chamber 44 is opened in the part of the cylinder 40 which this discharge chamber 44 formed and became thin.

The discharge port 42 is provided with a reed valve 43 (valve main body 43a and valve support 43b) which opens to the discharge chamber 44 side. The high pressure refrigerant gas G discharged from the compression chamber 48 through the discharge port 42 and the reed valve 43 to the discharge chamber 44 is formed in the communication hole (not shown) formed in the rear side block 30. ) Is discharged to the discharge chamber 15 via the oil separator 62 of the cyclone block 60.

Here, the refrigeration oil R separated by the oil separator 62 is dropped to the bottom of the discharge chamber 15 and stored in this bottom.

In addition, the compressor 100 is provided at the lower part of the discharge chamber 15 for lubrication between the rotary shaft 51 and the through support hole 32 and for supplying hydraulic pressure for the vane 58 to the vane groove 56. It has a structure for guiding the refrigerator oil (R) stored in the respective parts.

That is, the flow path 33 which reaches the through support hole 32 is formed in the rear side block 30, and in the cross section of the rear side block 30 which faces the rotor 50, in the through support hole 32 The recessed part 35 which communicates with the vane groove 56 through the micro clearance gap between the through support hole 32 and the rotating shaft 51 from the opening of the flow path 33 is formed.

Each of the concave portions 35 has a substantially fan-shaped outline, as shown by an imaginary line (double dashed line) in FIG. 2. And this yaw part 35 is formed in the position which communicates with the back pressure chamber of the vane groove 56 of the rotor 50 which rotates. In addition, a small yaw portion for guiding the high-pressure refrigerator oil R is further formed in the concave portion of the yaw portion 35 to form a compression chamber 48 corresponding to the end of the compression stroke. High pressure hydraulic pressure may be applied to the vane groove 56.

In addition, a through hole 46 connected to the flow path 33 of the rear side block 30 is provided at the bottom of the cylinder 40, and the front side block 20 of the through hole 46 is provided in the front side block 20. A flow path (not shown) for communicating the opening on the side of 20 with the through support hole 23 is formed, and the refrigeration oil R passes through a minute gap between the through support hole 23 and the rotation shaft 51. Thus, the refrigeration oil R is guided to the yaw portion 25 and the like formed on the surface of the front side block 20 that faces the rotor 50.

In addition, since the compressor 100 is a variable-capacity type gas compressor capable of varying the discharge amount of the refrigerant gas G to the outside, as shown in FIG. 2, the refrigerant gas G in the front side block 20 is shown. Compression chamber 48 corresponding to the compression stroke (hereinafter referred to as 48 generally refers to the compression chamber, and denotes 48 (C) when referring to the compression chamber corresponding to the compression stroke). At the portion, the refrigerant gas G inside the compression chamber 48 (C) corresponding to this compression chamber is moved into the suction chamber 13 which is a space having a pressure lower than the internal pressure of the compression chamber 48 (C). A bypass passage 70 for outflow is formed, and a spool valve 80 (bypass valve) for opening and closing the bypass passage 70 is provided, and the compression chamber 48 is opened by opening the spool valve 80. A portion of the refrigerant gas G of (C) flows out into the suction chamber 13 to reduce the capacity in the compression chamber 48 (C), and As a result, the amount of refrigerant gas G discharged from the compression chamber 48 (C) to the discharge chamber 44 is changed.

Here, the detailed structure of the bypass passage 70 and the spool valve 80 is demonstrated with reference to FIG. 3 (a) and 3 (c) are views in which the compression chambers 48 (C) and the front side blocks 20 arranged in the transverse direction are arranged in the longitudinal direction in FIG. 1, (a) Denotes a state in which the spool valve 80 closes the bypass passage 70 by applying the high pressure refrigerator oil R supplied from the through hole 46 (see FIG. 1) as the back pressure of the spool valve 80. (c) shows a state where the bypass passage 70 is opened by blocking the back pressure from being loaded.

First, the bypass passage 70 is located in the interior surrounded by the cylinder 40, the bypass hole opening 71 opened at the end face 28 of the front side block 20, and the bypass hole opening 71. It consists of a valve accommodating chamber 72 in which the spool valve 80 is slidably accommodated, and a communicating portion 73 which communicates with the suction chamber 13 from the valve accommodating chamber 72.

The spool valve 80 accommodated in the valve accommodation chamber 72 enters the bypass hole opening 71 and has an outer circumferential surface 83 that slides against the circumferential surface 71a of the bypass hole opening 71. The inside of the valve receiving chamber 72 adjacent to the part 81 and the iron part 81 and substantially perpendicular to the outer circumferential surface 83 and continuous to the bypass hole opening 71. It has the seating surface part 84 which abuts on the wall surface 72a, and can move forward and backward along the valve accommodation chamber 72. As shown in FIG.

In the state where the back pressure is loaded on the spool valve 80 and the iron portion 81 of the spool valve 80 enters the bypass hole opening 71 (FIG. 3 (a)), the back pressure is applied by the back pressure. The bypass passage 70 is closed by the seating surface portion 84 of the spool valve 80 being pressed against the valve wall inner wall surface 72a as the seat surface of the valve seat.

Therefore, the high-pressure refrigerant gas G does not flow out into the suction chamber 13 from the compression chamber 48 (C), and as shown in FIG. 3 (b), the bypass passage 70 is not formed. The compression stroke is started at the same timing as the case.

In the state where the seating surface portion 84 of the spool valve 80 is press-contacted to the valve storage chamber inner wall surface 72a as the seat surface of the valve seat (the bypass passage 70 is closed), the spool valve ( The front end face 82 of the iron portion 81 of the 80 is formed to be substantially in line with the end face 28 of the front side block 20.

On the other hand, in the state where the back pressure is not loaded on the spool valve 80, the spool valve 80 is formed by the internal pressure of the compression chamber 48 loaded on the front end face 82 of the iron portion 81. (I) The part 81 slides inside the valve accommodation chamber 72 so as to withdraw from the bypass hole opening 71 (FIG. 3C).

At this time, the seating surface portion 84 of the spool valve 80 is separated from the valve storage chamber inner wall surface 72a as the seat surface of the valve seat, and the iron portion 81 has its front end surface 82 receiving the valve. Since the gas retracts from the chamber inner wall surface 72a to the valve receiving chamber 72 side and is completely separated from the bypass hole opening 71, the refrigerant gas flowing into the bypass hole opening 71 from the compression chamber 48. (G) is a gap between the front end surface 82 of the spool valve 80 and the inner wall surface 72a of the valve accommodation chamber 72, that is, as shown in the schematic diagram of FIG. 4, from the bypass hole opening 71. Virtual surface of the cylindrical peripheral surface shape corresponding to the valve accommodation chamber 72 side part rather than the inner wall surface 72a of the valve accommodation chamber 72 among the traces of the outer peripheral surface 83 of the receding iron part 81 It passes through (area S2) and flows into the valve accommodation chamber 72. And the refrigerant gas G flows out from the valve accommodation chamber 72 to the suction chamber 13 through the communication part 73. As shown in FIG.

In this case, as shown in Fig. 3 (d), until the vane 58 passes through the bypass hole opening 71, it is in a position that is formally defined as a compression stroke based on, for example, the rotational position. Even in the compression chamber 48 (C), since the refrigerant gas G therein continues to flow through the bypass passage 70 into the suction chamber 13, the compression stroke is not actually started, and the vane ( The time point when the 58 passes the bypass hole opening 71 is the start of the compression stroke.

Therefore, opening the bypass passage 70 substantially delays the start timing of the compression stroke, thereby changing the capacity of the compression chamber 48 (C) at the start of compression.

And the installation angle position of the bypass passage 70 regarding the rotation direction of the rotor 50 can be calculated | required previously by calculation based on the capacity of the compression chamber 48 (C) at the time of a compression stroke start, and a discharge port The amount of the refrigerant gas G discharged from the 42 can be set.

By the way, the above-described variable displacement compressor 100 retracts the spool valve 80 to open the bypass passage 70, and thus the refrigerant gas G from the bypass hole opening 71 to the valve accommodation chamber 72. When the flow path passes through, the passage passes through the above-described virtual surface, but in the compressor 100 of the present embodiment, the area S2 of the virtual surface is twice as large as the flow passage area S1 of the bypass hole opening 71. The iron portion 81 withdraws from the displacement amount of the spool valve 80 (bypass hole opening 71) so that the percentage (opening ratio) of the area S2 of the virtual surface to the area S1 becomes 200%. The sum of the displacement amount and the distance h from the front end surface 82 of the iron portion 81 to the inner wall surface 72a of the valve accommodation chamber 72 is set.

On the other hand, the conventional compressor spools so that the area S2 of the virtual surface becomes similar to the opening area S1 (the percentage (opening ratio) of the area S2 of the virtual surface to the opening area S1 is 100%). The displacement amount of the valve 80 is set. In the conventional compressor, the inlet end of the bypass hole opening 71 (the end face of the front side block 20) from the outlet end (the front end face 82 of the spool valve 80 and the end face 28 of the front side block 20). This is because the flow path area S of the refrigerant gas G is constant over the gap between the gaps) so that the refrigerant gas G flows out smoothly.

However, in practice, the refrigerant gas G flowing into the bypass hole opening 71 and passing through the bypass hole opening 71 tries to proceed in the same direction as the bypass hole opening 71 extends. Touches the front end face 82 of the iron portion 81 of the spool valve 80, which is withdrawn, and then disperses around the front end face 82 and passes through the above-described virtual surface. It flows into the storage chamber 72.

For this reason, the inflow part from the bypass hole opening 71 to the valve accommodation chamber 72 acts as a flow resistance with respect to the refrigerant gas G, and in the conventional compressor, the flow rate of this bypass passage 70 is desired. It was difficult to secure as much. That is, it was not possible to reduce the amount of discharged refrigerant gas (volume efficiency) from the compressor main body to the level determined by calculation in advance.

However, in the compressor 100 of the present embodiment, due to the displacement of the spool valve 80, the inflow portion from the bypass hole opening 71 into the valve accommodation chamber 72, that is, the area S2 of the virtual surface is bypassed. Since the opening area S1 of the hole opening 71 is doubled, it is difficult for the inflow portion to become a flow path resistance, so that the flow rate of the bypass passage 70 can be ensured at a desired flow rate. That is, the amount of discharged refrigerant gas (volume efficiency) from the compressor main body can be reduced to the target value obtained by calculation in advance.

Here, FIG. 5 shows a graph showing an example of the relationship between the aperture ratio and the volumetric efficiency performed by the present inventors. This graph is obtained when the bypass hole opening 71 is installed at an angular position at which the calculated volumetric efficiency becomes 30% when the spool valve 80 is opened, and the opening ratio is changed from 0% to 350% in 50% units. It shows the change of actual volume efficiency.

According to the experimental results, at the opening ratio of 100% applied to the conventional compressor, the volumetric efficiency of about 40% is actually obtained with respect to 30% of the calculated volumetric efficiency, whereas it is applied to the compressor 100 of the present embodiment. At an opening ratio of 200%, a volume efficiency of 30% was obtained as the calculated target value.

The test results also revealed that the volumetric efficiency was followed at 30% even at an aperture ratio of over 200%. In addition, since the displacement amount of the spool valve 80 needs to be increased as the opening ratio is increased, the opening ratio of 200% is sufficient to obtain the desired volumetric efficiency. Therefore, in the compressor 100 of the present embodiment, the spool valve 80 The desired volumetric efficiency can be obtained while minimizing the increase in the amount of displacement of h).

As described above, according to the compressor 100 according to the present embodiment, the amount of discharge gas (volume efficiency) of the compressor main body can be varied as desired by opening and closing the spool valve 80.

In the compressor 100 according to the present embodiment, the compressor main body has a vane rotary type, and the bypass hole opening 71 corresponds to the front side block 20 corresponding to the compression stroke in which the volume of the compression chamber 48 decreases. Since the suction chamber 13 as a low pressure space is disposed adjacent to the front side block 20, the bypass passage 70 can be configured in a short length without having to configure a complicated path.

In addition, the compressor 100 of the above-described embodiment is a gas compressor in which the compressor main body is a vane rotary type, but the variable displacement gas compressor according to the present invention is not limited to the compressor main body of this type. The same applies to a variable displacement gas compressor having a reciprocating compressor body.

As described above, the present invention can provide a variable displacement gas compressor capable of precisely matching the outflow amount to a desired amount in selectively discharging a part of the gas in the compression stroke.

Claims (2)

And a compressor main body for compressing the sucked gas inside the cylinder and discharging the compressed gas, and the compressor main body is provided with a bypass passage for selectively discharging a part of the gas in the compression stroke into the low pressure space. At the same time, there is provided a bypass valve for opening and closing the bypass passage, and in the variable displacement gas compressor, the discharge gas amount can be varied by opening and closing the bypass valve. The bypass passage includes a bypass hole opening opened to the inside of the cylinder, a valve accommodation chamber continuous to the bypass hole opening, and the bypass valve is accommodated, and a communication portion communicating from the valve accommodation chamber to the low pressure space. Lose, The bypass valve accommodated in the valve accommodating chamber has a convex portion having an outer circumferential surface which rushes into the bypass hole opening and slides in contact with the circumferential surface of the bypass hole opening, and is adjacent to the convex portion. And a seating surface portion which is substantially orthogonal to the outer circumferential surface and abuts against an inner wall surface of the valve accommodation chamber that is continuous to the bypass hole opening portion. The open position of the bypass valve, in which the iron portion withdraws from the bypass hole opening portion to the valve accommodation chamber, is the distance between the tip of the iron portion and the inner wall surface and the circumferential length of the iron portion. A variable displacement gas compressor, characterized in that the path area calculated by the product of is equal to or more than twice the opening area of the bypass hole opening portion on the wall surface of the cylinder. The method of claim 1, The compressor main body includes: a rotor that is integrally rotated with a rotating shaft, a cylinder surrounding the outer side of the outer circumferential surface of the rotor, and a protruding tip protruding from the outer circumferential surface of the rotor, the protruding tip abutting the inner circumferential surface of the cylinder. A plurality of plate-shaped vanes disposed at equally spaced intervals, and two side blocks disposed from both end faces of the rotor so as to sandwich the rotor and the cylinder, respectively, A compressor body of a vane rotary type in which a volume of a compression chamber partitioned by two side blocks, the rotor, the cylinder, and two vanes which are moved back and forth with each other in a rotational direction of the rotor is repeated. And the bypass hole opening portion is formed in a side block corresponding to a compression stroke in which the volume of the compression chamber is reduced.

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