JPH02271094A - Control valve for variable displacement type scroll compressor - Google Patents

Abstract

PURPOSE:To enable flow compensation due to intake/discharge pressure by contructing the subject valve in such a way that low intake pressure expands a bellows to press in a plug and open an opening so as to reduce compression capacity, on the contrary, high intake pressure closes the opening to make the compression capacity maximum. CONSTITUTION:When an intake pressure is low, also the pressure in a first chamber 43 becomes low via an induction passage, a bellows 52 is expanded to press in a plug 50 to open an opening, fluid in a cylinder is passed through a second induction passage, a second chamber 44, an opening 42 and the first chamber 43 and flows in an intake chamber to open a bypass hole and compression capacity is reduced thereby. Meantime, when the intake pressure becomes high, the bellows 52 is contracted, the plug 50 closes the opening 42 due to urging force of a spring 51, the pressure in the cylinder rises to close the bypass hole, bypass between a fluid pocket and the intake chamber is not conducted to make the compression capacity maximum. Discharge pressure is introduced in a third chamber 46, back pressure is operated by a rod 54 to vary the compression capacity according to the discharge pressure. Thus, flow compensation can be carried out due to intake pressure and discharge pressure with a simple structure.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is used in a variable capacity scroll compressor, and moves the valve by adjusting the pressure applied to the back side of the valve in the cylinder. This invention relates to a control valve that opens and closes a bypass hole provided in a plate of a fixed scroll member, thereby changing the discharge capacity.

[Prior Art] A conventional control valve for a variable capacity scroll compressor of this type includes a casing, a first spiral body on one surface of a first plate body, and a fixed valve fixed in the casing. a scroll member, a movable scroll member having a second spiral body on one surface of a second plate and forming a fluid pocket in combination with the fixed scroll member, and a suction chamber formed in the casing; a discharge chamber formed in the casing; a bypass hole formed in the first plate and communicating with the fluid pocket; a cylinder with one end communicating with the bypass hole and the suction chamber; The valve is slidably inserted into one end of the cylinder to open and close the bypass hole, and is biased in the direction of opening the bypass hole. It is arranged on the other end side and is adapted to adjust the pressure within the cylinder to control the movement of the valve.

In the conventional case, the cylinder communicates with the discharge chamber via an orifice.

On the other hand, the control valve includes a first chamber having an opening at one end, a second chamber that communicates with the first chamber through the opening, and a control valve that is provided in the second chamber and opens and closes the opening. and a stopper biased in a direction to close the opening, a bellows having a pin that abuts the stopper through the opening and provided in the first chamber, and connecting the suction chamber and the first chamber. The first thing that goes through
and a second introduction path communicating the cylinder and the second chamber.

When the suction pressure is low in this conventional variable capacity scroll compressor using a control valve, the bellows expands and pushes the plug through the pin, which opens the opening and connects the first inlet path and the second inlet path. Via the channel, the fluid in the cylinder flows into the suction chamber and the pressure in the cylinder decreases. As a result, the valve is moved by the biasing force, the bypass hole is opened, and the compression capacity is reduced.

On the other hand, when the suction pressure increases, the bellows contracts and no longer presses the stopper, and the stopper closes the opening due to its biasing force.
The outlet for the discharge gas introduced into the cylinder is blocked, and the pressure inside the cylinder increases. As a result, the back pressure on the valve increases and the valve moves against the biasing force, closing the bypass hole and maximizing the compression capacity.

In this manner, in the case of a variable capacity scroll compressor using a conventional control valve, the capacity is variable depending on the suction pressure, and therefore the discharge flow rate is compensated by the suction pressure.

C. Problems to be Solved by the Invention] In order to perform flow rate compensation more accurately, it is desirable to perform flow rate compensation not only for suction pressure but also for discharge pressure.

However, in a variable capacity scroll compressor using a conventional control valve, when flow rate compensation is performed for discharge pressure, an orifice installed in the discharge gas passage and a discharge pressure The structure becomes complicated in terms of sealing properties of the retractably provided rod portion.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a control valve for a variable capacity scroll compressor that can perform flow rate compensation based on suction pressure and discharge pressure with a simple structure.

[Means for Solving the Problems] According to the present invention, a casing, a fixed scroll member having a first spiral body on one surface of a first plate body and fixed in the casing, and a second a movable scroll member having a second spiral body on one surface of the plate body and forming a fluid pocket in combination with the fixed scroll member; a suction chamber formed in the casing; a discharge chamber, a bypass hole formed in the first plate and communicating with the fluid pocket, a cylinder whose one end communicates with the bypass hole and the suction chamber, and which is slidable toward one end within the cylinder. A variable capacity scroll type compressor including a valve inserted into the cylinder to open and close the bypass hole and biased in the direction of opening the bypass hole, the valve being disposed at the other end of the cylinder. The control valve that controls the movement of the valve by adjusting the pressure in the cylinder includes a first chamber having an opening at one end, and a second chamber communicating with the first chamber through the opening. a third chamber separated from the second chamber by a wall; a plug provided in the second chamber and biased in a direction to open and close the opening; A bellows having a bottle that contacts the stopper and is provided in the first chamber; a rod that is provided in the wall so as to be retractable and that comes into contact with the stopper; Communication Zuru 1st
a second introduction path that communicates between the cylinder and the second chamber, a third introduction path that communicates the discharge chamber and the third chamber, and the discharge chamber and the cylinder. There is obtained a control valve for a variable capacity scroll type compressor, characterized in that it includes an orifice that communicates with the control valve.

[Operation] In the variable capacity scroll compressor using the control valve of the present invention, when the suction pressure is low, the first chamber communicates with the suction chamber through the first introduction path. pressure will also be lower. The bellows therefore swells and forces the stopper through the bottle, which opens the opening and opens the second inlet channel,
through the second chamber, the opening, the first chamber and the first introduction passage;
The fluid inside the cylinder flows into the suction chamber and the pressure inside the cylinder decreases. As a result, the valve is moved by the biasing force, the bypass hole is opened, and the compression capacity is reduced.

On the other hand, when the suction pressure increases, the bellows contracts and no longer presses the stopper, and the stopper closes the opening due to its biasing force.
The inside of the cylinder is sealed.

The pressure inside the cylinder increases due to the fluid flowing into the cylinder through the orifice.

As a result, the back pressure on the valve increases, causing the valve to move against the biasing force, closing the bypass hole and eliminating bypass between the fluid pocket and the suction chamber, resulting in maximum compression capacity. .

In addition to the flow rate compensation using the suction pressure as described above, in the case of a variable capacity scroll compressor using the control valve of the present invention, the flow rate compensation is also performed using the discharge pressure.

That is, in the case of a variable capacity scroll compressor using the control valve of the present invention, the third chamber communicates with the discharge chamber through the third introduction path. Therefore, the pressure in the third chamber corresponds to the discharge pressure. Therefore, when the discharge pressure increases, the pressure in the third chamber increases, and as a result, stronger back pressure is applied to the rod, causing the rod to direct the stopper toward the opening.
Press harder. Therefore, in this case, the opening will not open unless the suction pressure becomes lower than when the discharge pressure is low.

Conversely, if the discharge pressure becomes low, the pressure in the third chamber will also become low, resulting in less back pressure on the rod and the rod pressing less against the bung. . Therefore, in this case, the opening opens before the suction pressure becomes much lower than when the discharge pressure is high.

[Embodiment] FIG. 1 is a sectional view of a variable capacity scroll compressor using a control valve according to an embodiment of the present invention.

Referring to FIG. 1, a casing 1 consists of a cup-shaped portion 2 and a front end plate 3. As shown in FIG.

The fixed scroll member 4 has a first spiral body 6 on one surface of a first plate body 5. The fixed scroll member 4 is fixed to the bottom wall 2a of the cup-shaped portion 2.

The movable scroll member 10 has a second spiral body 12 on one surface of a second plate body 11. Movable scroll member 1
0 is combined with a fixed scroll member 4 to form a fluid pocket 13 therebetween.

A suction boat (not shown) is attached to the casing 1. Therefore, the pressure inside the casing 1 becomes the suction pressure, and the fixed scroll member 4 and the movable scroll member 1
The space inside the casing 1 except for the space inside the casing 1 constitutes a suction chamber 14.

A discharge port 15 is provided in the center of the first plate 5,
A valve 16 is attached to the discharge port 15.

Further, a discharge chamber 17 is formed in the center of the first plate 5 so as to communicate with the discharge port 15 .

Figure 2 is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 is a cross-sectional view from Figure 1 ■.
It is a sectional view taken along the line -■.

Referring also to FIGS. 2 and 3, a first bypass hole 20 is formed in the first plate 5. As shown in FIG.

The first bypass hole 20 has two communication holes 21 and two communication holes 21.
and an intermediate chamber 22 connecting two communication holes 21.

The first bypass hole 20 is provided at a location where the fluid pocket 13 decreases in volume while moving toward the center of each spiral body 6, 12, and the volume becomes 40% of the maximum intake volume. ing. Two first bypass holes 20 are provided because the fluid pockets 13 are formed in pairs.

Each communication hole 21 is provided with a valve 23, respectively.

On the other hand, a second bypass hole 24 is also formed in the first plate body 5 . The second bypass hole 24 is connected to the fluid pocket 1
3 is provided where the volume is 10% of the maximum intake volume. Where this second bypass hole 24 is formed, there is now only one fluid pocket 13, so only one second bypass hole 24 is provided.

Returning to FIG. 1, a cylinder 30 is formed on the outside of the bottom surface of the cup-shaped portion 2. One end of the cylinder 30 communicates with the first bypass hole 20 through a hole 31 formed in the bottom wall 2a, and communicates with the second bypass hole 24 through a hole 32 formed in the bottom wall 2a. is familiar with Further, the cylinder 30 communicates with the suction chamber 14 through a hole 33 formed in the bottom wall 2a and a spring storage chamber 36, which will be described later.

A shuttle valve 34 is provided at one end of the cylinder 30.
is slidably inserted. This shuttle valve 34
moves to open and close the holes 31 and 32, and thereby the shuttle valve 34 indirectly opens and closes the first bypass hole 20 and the second bypass hole 24. A spring 35 causes the shuttle valve 34 to always close the hole 31. ,3
2 is biased in the direction of opening. The spring 35 is placed in a spring storage chamber 36 connected to one end of the cylinder 30.
It is contained within.

On the other end side of the cylinder 30, there is a control valve 40 of this embodiment.
is located.

FIG. 4 is a sectional view of the control valve of this embodiment.

Referring to FIGS. 1 and 4, the control valve 40 includes a first chamber 43 having an opening 42 at one end in a case body 41;
A second chamber 44 communicating with the first chamber 43 through an opening 42, and a third chamber 46 provided with a wall 45 separating the second chamber 44.
This is provided.

A ball 50, which is a stopper, is provided in the second chamber 44 and opens and closes the opening 42, and a spring 51 is applied in the direction of closing the opening 42.
is energized by.

The bellows 52 is provided within the first chamber 43,
It has a vial 53 which abuts the ball 50 through the opening 42.

The rod 54 is provided on the wall 45 so as to be able to move forward and backward, and its tip abuts against the ball 50.

The control valve 40 has a first introduction passage 61 that communicates between the suction chamber 14 and the first chamber 43 , a second introduction passage 62 that communicates between the cylinder 30 and the second chamber 44 , and a discharge chamber 17 . It has a third introduction path 63 that communicates with the third chamber 46, and an orifice 4 that communicates the discharge chamber 17 with the cylinder 30.

The first introduction path 61 includes a first passage 70 provided in the first plate 5 and a first passage 70 provided in the bottom wall 2a of the cup-shaped portion 2.
through hole 7], a first gap 72 formed between a step formed on the inner wall of the cylinder 30 and a step formed on the outer wall of the case body 41, and a first gap 72 formed on the side wall of the case body 41. and a second through hole 73.

The second introduction path 62 is formed within the case body 41.

The third introduction path 63 is formed in a second passage 80 provided in the first plate 5, a third through hole 81 bored in the bottom plate 2a of the cup-shaped portion 2, and an inner wall of the cylinder 30. The second gap 82 is formed between the step part formed in the case body 41 and the step part formed in the case body 41, and a third passage 83 is formed in the case body 41. A filter 84 is provided within the second passage 80 .

The orifice 64 is constructed by creating a small gap between the wall 45 and the rod 54.

In this embodiment, the first introduction path is passed through the first plate body, but it is not necessary to configure it in this way. For example, a vibrator or the like can be used to directly connect the inhalation chamber and the first It may also be communicated with the room.

Similarly, the third introduction path does not need to pass through the first plate body, and the discharge chamber and the third chamber may be directly communicated with each other by a pipe or the like.

FIGS. 5(a) to 5(c) are sectional views of essential parts showing the operation of a variable capacity scroll compressor using the control valve of this embodiment.

Referring to FIGS. 5(a) and 4, when the compressor starts rotating, the discharge pressure increases and the gas passes through the third introduction path 63 and orifice 64 and enters the second chamber 44. Inflow. At this time, since the pressure in the first chamber 43 is the balance pressure when stopped, the bellows 52 contracts and the ball 50
Pushed by the spring 51, the opening 42 is closed and the second chamber 4
4 from the discharge chamber 17, the gas flows into the second introduction path 62.
is introduced into the cylinder 30, and the shuttle valve 34 is pushed to close the bypass hole 20.24 and reach maximum capacity.

Referring to FIGS. 5(b), (c), and FIG. 4, as the rotation speed of the compressor increases and the suction pressure (Ps) decreases, the pressure in the first chamber 43 decreases. . Accordingly, bellows 5
2 extends and pushes up the ball 50 (Ps setting value),
The second chamber 44 and the first chamber 43 communicate with each other, and the gas in the cylinder 30 that was pushing the shuttle valve 34 is transferred to the second introduction path 62, the second chamber 44, the opening 42, and the first chamber 43. The shuttle valve 34 is pushed in the opposite direction by the spring 35, opens the bypass hole 20.24, and performs capacity control. At this time, the position of the shuttle valve 34 within the cylinder 30 is determined by the balance between the repulsive force of the spring 35 and the pressure (Pc) within the cylinder 30. The pressure inside the cylinder 30 here is determined by the flow rate of gas entering the second chamber 44 through the third introduction path 63 and orifice 64, and the second
It is determined by the relationship with the gas flow rate that passes from the chamber 44 to the suction chamber 14 through the first chamber 43 and the first introduction path 61.

Flow rate of gas flowing into the second chamber 44 from the A-niorifice 64.

B: Gas flow rate from the second chamber 44 to the suction chamber 14.

Then, (1) A>B→The pressure inside the cylinder 30 increases, and the shuttle valve 34 closes the bypass hole 20.24.

(2) A<B--The pressure in the cylinder 30 is released to the suction chamber 14, and the shuttle valve 34 opens the bypass hole 20°24.

Here, B changes depending on the amount by which the bellows 52 pushes the ball 5o, so it changes depending on the suction pressure. As a result, the pressure inside the cylinder 30 is automatically adjusted, and the bypass hole opening/closing position of the shuttle valve 34 is also controlled according to the suction pressure.

On the other hand, the rod 54 in the third chamber 46 always receives discharge pressure from the third introduction path 63, and applies force in the opposite direction to the direction in which the bottle 53 of the bellows 52 pushes the ball 50. As a result, a force corresponding to the discharge pressure is applied to the ball 50, and the point at which the bottle 53 pushes up the ball 50 (
Ps setting value) will also change accordingly. For example, when the discharge pressure is high, the force applied to the rod 54 also increases, so a large force is required when the pin 53 of the bellows 52 pushes up the ball 5°. Therefore, the Ps setting value decreases. Conversely, when the discharge pressure is low, the Ps setting value becomes high. .

FIG. 6 is a sectional view of a control valve according to another embodiment.

Referring to FIG. 6, in the case of this control valve, there is no gap forming an orifice between the wall 45 and the rod 54, and the gap between the wall 45 and the rod 54 is It is sealed by an O-ring 91 placed in a groove 90 provided in the. The orifice 64 is connected to the case body 4.
It is provided at the bottom of 1. The other parts are the same as the embodiment shown in FIG.

[Effects of the Invention] If the control valve of the present invention is used in a variable capacity scroll compressor, the flow rate can be compensated not only by the suction pressure but also by the discharge pressure with a simple configuration. Therefore, it becomes possible to perform detailed control according to the suction pressure and the discharge pressure.

In particular, in the case of the invention as claimed in claim 2, by not providing a seam member in the rod part that receives the discharge pressure, and by making the gap function as an orifice, the structure can be simplified and the friction of the rod part can be reduced. The influence on control characteristics can be avoided, and fine control can be performed.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a variable capacity scroll compressor using a control valve according to an embodiment of the present invention, and Fig. 2 is a sectional view of a variable capacity scroll compressor using a control valve according to an embodiment of the present invention.
■A cross-sectional view along the line, Figure 3 is a cross-sectional view along the ■-■ line in Figure 1,
FIG. 4 is a sectional view of the control valve of the same embodiment, and FIGS. 5(a) to (c) are sectional views of essential parts showing the operation of a variable capacity scroll compressor using the control valve of the same embodiment. , FIG. 6 is a sectional view of a control valve according to another embodiment. 1...Casing, 2...Cup-shaped part, 3...
Front end plate, 4... fixed scroll member, 5... first plate body, 6... first spiral body, 1
0... Movable scroll member, 11... Second plate body,
12... Second spiral body, 13... Fluid pocket, 14... Suction chamber, 15... Discharge port, 16... Valve, 17... Discharge chamber, 20... First bypass hole, 2
1...Communication hole, 22...Intermediate chamber, 23...Valve, 2
4... Second bypass hole, 30... Cylinder, 3
1.32.33...hole, 34...shuttle valve,
35...Spring, 36...Spring storage chamber,
40... Control valve, 41... Case body, 42... Opening, 43... First chamber, 44... Second chamber, 45...
...Wall, 46...Third chamber, 50...Ball, 51
... Spring, 52 ... Bellows, 53 ... Bottle, 5
4... Rod, 61... First introduction path, 62...
Second introduction path, 63... Third introduction path, 64... Orifice, 70... First passage, 71... First through hole, 72... First gap, 73...Second through hole, 8
0...Second passage, 81...Third through hole, 82...
- Second gap, 83...Third passage, 84...Filter, 90...Groove, 91...0 ring. Figure 4 Figure 6

Claims (2)

[Claims] 1. a casing, a fixed scroll member having a first spiral body on one surface of a first plate and fixed in the casing, and a fixed scroll member having a second spiral body on one surface of a second plate; a movable scroll member that is combined with the fixed scroll member to form a fluid pocket; a suction chamber formed in the casing; a discharge chamber formed in the casing; a bypass hole communicating with the pocket; a cylinder having one end communicating with the bypass hole and the suction chamber; and a cylinder slidably inserted into the one end side of the cylinder to open and close the bypass hole and open the bypass hole. It is used in a variable capacity scroll type compressor that includes a valve biased in the direction, and is arranged on the other end side of the cylinder and controls the movement of the valve by adjusting the pressure inside the cylinder. A control valve comprising a first chamber having an opening at one end, a second chamber communicating with the first chamber through the opening, and a third chamber separated from the second chamber by a wall. a chamber, a stopper provided in the second chamber and biased in a direction to open and close the opening, and a pin that abuts the stopper through the opening and is located in the first chamber. a bellows provided therein; a rod provided in the wall so as to be freely retractable and in contact with the plug;
A first introduction passage that communicates the suction chamber and the first chamber, a second introduction passage that communicates the cylinder and the second chamber, and a discharge chamber and the third chamber. A control valve for a variable capacity scroll type compressor, characterized in that it includes a communicating third introduction passage and an orifice communicating the discharge chamber and the cylinder. 2. The control valve for a variable capacity scroll type compressor according to claim 1, wherein the orifice is configured by creating a gap between the wall and the rod. Machine control valve.