JP2815387B2 - Control valve for variable displacement scroll compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is used for a variable displacement scroll compressor, in which a valve is moved by adjusting a pressure applied to a back surface of a valve in a cylinder. The present invention relates to a control valve for opening and closing a bypass hole provided in a plate of a fixed scroll member by this valve, thereby changing a discharge capacity.

[Prior Art] A conventional control valve for a variable displacement scroll compressor of this type includes a casing and a first spiral body on one surface of a first plate body, and is fixed in the casing. A scroll member, a movable scroll member having a second spiral body on one surface of a second plate body 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 body and communicating with the fluid pocket, a cylinder having one end communicating with the bypass hole and the suction chamber, A variable displacement scroll compressor including a valve slidably inserted at one end and opening and closing the bypass hole and urged in a direction to open the bypass hole. It is arranged on the other end side of the cylinder, and is adapted to control the movement of the valve by adjusting the pressure in the cylinder.

In the case of the related art, the cylinder communicates with the discharge chamber via an orifice.

On the other hand, the control valve has a first chamber having an opening at one end,
A second chamber that communicates with the first chamber through the opening, a plug provided in the second chamber that opens and closes the opening, and is urged in a direction to close the opening; A bellows having a pin abutting on a stopper and provided in the first chamber, a first introduction path communicating the suction chamber with the first chamber, the cylinder and the second chamber; And a second introduction path communicating therewith.

When the suction pressure is low in the variable displacement scroll compressor using the conventional control valve, the bellows expands and pushes the stopper through the pin, whereby the opening is opened and the first opening is opened.
The fluid in the cylinder flows into the suction chamber through the introduction path and the second introduction path, and the pressure in the cylinder decreases.
As a result, the valve is moved by the urging force, the bypass hole is opened, and the compression capacity is reduced.

Conversely, if the suction pressure increases, the bellows shrink,
The stopper is no longer pressed, and the stopper closes the opening due to the urging force of the stopper, so that the passage of the discharge gas introduced into the cylinder is closed, and the pressure in the cylinder increases.
As a result, the back pressure of the valve increases, and the valve moves against its biasing force, closing the bypass hole and maximizing the compression capacity.

As described above, in the case of the variable displacement scroll compressor using the conventional control valve, the displacement becomes variable depending on the level of the suction pressure, and therefore the discharge flow rate is compensated by the suction pressure.

[Problem to be Solved by the Invention] When performing flow rate compensation more accurately, not only the suction pressure,
It is desired that flow rate compensation is performed for the discharge pressure.

However, in a variable displacement scroll type compressor using a conventional control valve, when the flow rate is compensated for the discharge pressure, the orifice installed in the passage of the discharge gas, and the discharge pressure is reciprocated to perform the flow rate compensation. The structure becomes complicated with respect to the sealing property of the freely provided rod portion.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control valve for a variable displacement scroll compressor capable of compensating for a flow rate by a suction pressure and a 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, A movable scroll member having a second spiral wound 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; and a suction chamber formed in the casing. A discharge chamber, a bypass hole formed in the first plate body and communicating with the fluid pocket, a cylinder having one end communicating with the bypass hole and the suction chamber, and slidable toward one end of the cylinder. Used in a variable displacement scroll compressor including a valve inserted into the cylinder to open and close the bypass hole and biased in a direction to open the bypass hole, the valve being disposed on the other end side of the cylinder. A control valve for controlling the movement of the valve by adjusting the pressure in the cylinder, wherein a first chamber having an opening at one end;
A second chamber communicating with the first chamber through the opening, a third chamber separated from the second chamber by a wall, and opening and closing the opening provided in the second chamber. And a stopper urged in a direction to close the opening, a bellows having a pin that comes into contact with the stopper through the opening and provided in the first chamber, A rod coming into contact with the stopper, a first introduction path communicating the suction chamber with the first chamber, a second introduction path communicating the cylinder with the second chamber, and the discharge chamber. A control valve for a variable displacement scroll compressor, comprising a third introduction passage communicating with the third chamber, and an orifice communicating the discharge chamber with the cylinder, is obtained. .

[Operation] In the variable displacement 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, so that the first chamber is connected. Pressure is also reduced. For this purpose, the bellows swells and pushes the plug through the pin, which opens the opening and passes through the second inlet, the second chamber, the opening, the first chamber and the first inlet and into the cylinder. Fluid flows into the suction chamber, and the pressure in the cylinder drops. As a result, the valve is moved by the urging force, the bypass hole is opened, and the compression capacity is reduced.

Conversely, if the suction pressure increases, the bellows shrink,
The stopper is no longer pressed, and the stopper closes the opening due to the urging force, and the inside of the cylinder is closed. Then, the pressure in the cylinder increases due to the fluid flowing into the cylinder through the orifice. As a result, the back pressure of the valve increases, the valve moves against the biasing force, closes the bypass hole, and the bypass between the fluid pocket and the suction chamber is not performed, so that the compression capacity is maximized. .

Thus, in the case of the variable displacement scroll compressor using the control valve of the present invention, at the same time as the flow rate compensation by the suction pressure,
Flow compensation is also performed by the discharge pressure.

That is, in the case of the variable displacement 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 becomes a pressure corresponding to the discharge pressure. Therefore, when the discharge pressure increases, the pressure in the third chamber increases, and as a result, a stronger back pressure is applied to the rod, and the rod presses the stopper toward the opening more strongly. Therefore, in this case, the opening cannot be opened unless the suction pressure becomes lower than in the case where the discharge pressure is low.

Conversely, when the discharge pressure decreases, the pressure in the third chamber also decreases, and as a result, the back pressure of the rod decreases, and the rod does not press the stopper much. . Therefore, in this case, the opening is opened before the suction pressure becomes much lower than when the discharge pressure is high.

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

Referring to FIG. 1, a casing 1 includes a cup-shaped portion 2.
And a front end plate 3.

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

The movable scroll member 10 has a second plate 11 on one surface thereof.
The spiral body 12 is provided. The movable scroll member 10
In combination with the fixed scroll member 4, a fluid pocket 13 is formed therebetween.

A suction port (not shown) is attached to the casing 1. Therefore, the pressure in the casing 1 becomes the suction pressure, and the fixed scroll member 4 and the movable scroll member
The space inside the casing 1 excluding 10 and the like constitutes a suction chamber 14.

A discharge port 15 is provided at the center of the first plate body 5,
The discharge port 15 is provided with a valve 16.

A discharge chamber 17 is formed at the center of the first plate 5 so as to communicate with the discharge port 15.

2 is a cross-sectional view taken along the line II-II in FIG. 1, and FIG.
It is sectional drawing in the III-III line.

Referring also to FIG. 2 and FIG.
A first bypass hole 20 is formed. The first bypass hole 20 includes two communication holes 21 and an intermediate chamber 22 connecting the two communication holes 21. The first bypass hole 20 is
The fluid pocket 13 is provided at a position where the volume of the fluid pocket 13 is reduced while moving toward the center of each of the spirally wound bodies 6 and 12, and the volume becomes 40% of the maximum intake volume. Two first bypass holes 20 are provided because the fluid pockets 13 are formed as a pair. Each communication hole 21 is provided with a valve 23.

On the other hand, a second bypass hole 24 is also formed in the first plate 5. The second bypass hole 24 is provided in the fluid pocket 13
Is provided at a point where the volume becomes 10% of the maximum intake volume. In the place where the second bypass hole 24 is formed,
Since the fluid pocket 13 is no longer one, the second
, Only one bypass hole 24 is provided.

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

A shuttle valve 34 is slidably inserted into one end of the cylinder 30. The movement of the shuttle valve 34 opens and closes the holes 31 and 32, whereby the shuttle valve 34 indirectly opens and closes the first bypass hole 20 and the second bypass hole 24. The shuttle valve 34 is constantly urged by a spring 35 in a direction to open the holes 31 and 32. The spring 35 is housed in a spring storage chamber 36 connected to one end of the cylinder 30.

On the other end side of the cylinder 30, the control valve 40 of the present embodiment is arranged.

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

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

A ball 50 as a stopper is provided in the second chamber 44 and has an opening.
It is urged by a spring 51 in a direction to open and close the opening 42 and close the opening 42.

The bellows 52 is provided in the first chamber 43, and has a pin 53 that contacts the ball 50 through the opening 42.

The rod 54 is provided on the wall 45 so as to be able to move back and forth, and the tip thereof comes into contact with the ball 50.

The control valve 40 is a first valve that communicates between the suction chamber 14 and the first chamber 43.
, A second introduction path 62 that communicates the cylinder 30 with the second chamber 44, a third introduction path 63 that communicates the discharge chamber 17 with the third chamber 46, and a discharge chamber 17. And an orifice 64 that communicates with the cylinder 30.

The first introduction path 61 includes a first passage 70 provided in the first plate body 5, a first through hole 71 formed in the bottom wall 2 a of the cup-shaped member 2, and an inner wall of the cylinder 30. First gap generated between the formed step and the step formed on the outer wall of case body 41
72 and a second through hole 73 formed in the side wall of the case body 41.

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

The third introduction path 63 is a second passage provided in the first plate 5.
80 and a third through hole 81 formed in the bottom plate 2a of the cup-shaped member 2.
And a step formed on the inner wall of the cylinder 30 and the case body 41
And a third passage 83 formed in the case body 41. A filter 84 is provided in the second passage 80.

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

In the present embodiment, the first introduction path is made to pass through the first plate body. However, it is not always necessary to make such a configuration, and for example, the suction chamber and the first chamber are directly connected by a pipe or the like. May be communicated with.

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.

5 (a) to 5 (c) are cross-sectional views of main parts showing the operation of the variable displacement scroll compressor using the control valve of the present embodiment.

With reference to FIGS. 5 (a) and 4, when the compressor starts rotating, the discharge pressure increases, and the gas passes through the third introduction passage 63 and the orifice 64 to the second chamber 44. Inflow. At this time, since the pressure in the first chamber 43 is a balanced pressure when stopped, the bellows 52 contracts, the ball 50 is pushed by the spring 51, the opening 42 is closed, and the discharge chamber is connected to the second chamber 44. The gas flowing in from 17 passes through the second introduction path 62 and passes through the cylinder 30
The shuttle valve 34 is pushed into the bypass hole
20 and 24 are closed to reach the maximum capacity.

With reference to FIGS. 5 (b), (c) and 4, when the rotational speed of the compressor increases and the suction pressure (Ps) decreases, the pressure in the first chamber 43 decreases. . When the bellows 52 extends and pushes up the ball 50 (Ps set value), the second chamber
The gas in the cylinder 30, which has communicated with the first chamber 43 and pressed the shuttle valve 34, flows into the second introduction path 62, the second chamber 44, the opening 42, the first chamber 43, and the first chamber 43. Go through the introduction route 61,
The shuttle valve 34 is pushed into the suction chamber 14 in the opposite direction by the spring 35 to open the bypass holes 20 and 24, and the capacity is controlled. At this time, the position of the shuttle valve 34 in the cylinder 30 is determined by the repulsion of the spring 35 and the cylinder.
Determined by the balance with the pressure (Pc) within 30. Here, the pressure in the cylinder 30 passes through the third introduction path 63 and the orifice 64 and the gas flow rate into the second chamber 44 and the second chamber 44.
44 through the first chamber 43 and the first introduction path 61,
It depends on the relationship with the flow rate of gas flowing out.

 A: The flow rate of gas flowing from the orifice 64 into the second chamber 44.

 B: Flow rate of gas flowing from the second chamber 44 to the suction chamber 14.

Then, (1) A> B → the pressure in the cylinder 30 increases, and the shuttle valve 34 closes the bypass holes 20 and 24.

(2) A <B → The pressure in the cylinder 30 is released into the suction chamber 14, and the shuttle valve 34 opens the bypass holes 20, 24.

Here, since B changes depending on the amount by which the bellows 52 pushes up the ball 50, B changes by closing to the suction pressure. As a result, the pressure in the cylinder 30 is automatically adjusted, and the opening / closing position of the bypass hole of the shuttle valve 34 is controlled in accordance with the suction pressure.

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

 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, the wall 45 and the rod
No gap is formed between the wall 45 and the rod 54, and the gap between the wall 45 and the rod 54 is sealed by an O-ring 91 disposed in a groove 90 provided in the wall 45. I have. The orifice 64 is provided at the bottom of the case body 41. Other parts are the same as those of the embodiment shown in FIG.

[Effects of the Invention] When the control valve of the present invention is used in a variable displacement 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, fine control can be performed according to the suction pressure and the discharge pressure.

In particular, in the case of the invention described in claim 2, no sealing material is provided on the rod portion receiving the discharge pressure, and the gap has an effect as an orifice, so that the structure is simplified and friction due to the rod portion is reduced. Influence on control characteristics can be avoided, and fine-grained control can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a variable displacement scroll compressor using a control valve according to an embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1, FIG. 4 is a cross-sectional view of the control valve of the embodiment, FIG.
(C) is a sectional view of a main part showing the operation of the variable displacement scroll compressor using the control valve of the embodiment, and FIG. 6 is a sectional view of a control valve according to another embodiment. DESCRIPTION OF SYMBOLS 1 ... Casing, 2 ... Cup-shaped part, 3 ... Front end plate, 4 ... Fixed scroll member, 5 ...
1st plate body, 6 ... 1st spiral body, 10 ... movable scroll member, 11 ... 2nd board body, 12 ... 2nd spiral body, 13 ... fluid pocket, 14 ... suction Chamber, 15 discharge port, 16 valve, 17 discharge chamber, 20 first bypass hole, 21 communication hole, 22 intermediate chamber, 23 valve, 24 second Bypass hole, 30 …… Cylinder, 31,32,33 …… Hole,
34 …… Shuttle valve, 35 …… Spring, 36 …… Spring storage room, 40 …… Control valve, 41 …… Case body, 42 ……
Opening 43, first chamber 44, second chamber 45, wall 46
... The third chamber, 50, the ball, 51, the spring, 52, the bellows, 53, the pin, 54, the rod, 61, the first introduction path, 62, the second introduction path, 63 …… Third introduction route, 64 ……
Orifice, 70... First passage, 71... First through hole, 72
... 1st gap, 73 ... 2nd passage, 80 ... 2nd passage, 81 ... 3rd passage, 82 ... 2nd gap, 83 ... 3rd
Passage, 84 …… Filter, 90 …… Groove, 91 …… O-ring.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F04C 18/02 311 F04C 29/10 311

Claims (2)

(57) [Claims] 1. A casing, a fixed scroll member having a first spiral on one surface of a first plate and fixed in the casing, and a second spiral on one surface of a second plate. A movable scroll member having a body and 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 formed in the fluid pocket, and a cylinder having one end communicating with the bypass hole and the suction chamber; and a slidably inserted one end of the cylinder to open and close the bypass hole; A variable displacement scroll compressor including a valve urged in a direction to open the bypass hole, and is disposed at the other end of the cylinder to regulate the pressure in the cylinder. A control valve for controlling the movement of the valve, a first chamber having an opening at one end, a second chamber communicating with the first chamber through the opening, and a second chamber and a wall. A third chamber provided in the second chamber, a plug provided in the second chamber, which opens and closes the opening and is urged in a direction to close the opening, and a pin which comes into contact with the plug through the opening. And a bellows provided in the first room;
A rod provided on the wall so as to be able to move back and forth and abutting on the stopper, a first introduction path communicating the suction chamber and the first chamber, and a communication between the cylinder and the second chamber. A variable capacity including a second introduction path, a third introduction path communicating the discharge chamber with the third chamber, and an orifice communicating the discharge chamber with the cylinder. Control valve for type scroll compressor. 2. A control valve for a variable displacement scroll compressor according to claim 1, wherein said orifice is formed by creating a gap between said wall and said rod. Control valve for variable scroll compressor.