JP2006112271A - Control valve for variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control valve for a variable displacement compressor improving sliding nature of shaft transmitting change of suction pressure to a valve element and improving controllability. <P>SOLUTION: In the control valve for the variable displacement compressor of a structure dividing a plunger of a solenoid into two of a first plunger 26 and a second plunger 2 and having a diaphragm 29 sensing suction pressure Ps arranged therebetween, the second plunger 22 is retained by a spring 24 energizing the same in a direction separating from the diaphragm 29 and is made abut on a shaft 17 transmitting change of suction pressure Ps sensed by the diaphragm 29 to the valve element 16. Consequently, since couple of force does not act on the shaft 17 and nature of sliding is not deteriorated even if attraction force is generated and the second plunger 22 moves, controllability can be improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control valve for a variable capacity compressor, and more particularly to a control valve for a variable capacity compressor suitable for controlling a refrigerant discharge capacity in a variable capacity compressor of an automotive air conditioner.

  The compressor used in the refrigeration cycle of the air conditioner for automobiles cannot control the rotational speed because it uses an engine whose rotational speed varies depending on the running state as a drive source. Therefore, in general, a variable capacity compressor capable of varying the refrigerant discharge capacity is used in order to obtain an appropriate cooling capacity without being restricted by the engine speed.

  In a variable capacity compressor, generally, an oscillating plate provided with a variable inclination angle is driven by a rotary motion of a rotating shaft in an airtight crank chamber, and the oscillating motion of the oscillating plate is performed. Thus, the piston reciprocating in the direction parallel to the rotation axis sucks the refrigerant in the suction chamber into the cylinder and compresses it, and then discharges it into the discharge chamber. At this time, by changing the pressure in the crank chamber, the inclination angle of the swing plate can be changed, whereby the stroke of the piston is changed and the discharge amount of the refrigerant is changed. The control valve for the variable capacity compressor controls the pressure in the crank chamber to change.

  Such a variable capacity compressor control valve for variably controlling the discharge capacity of the variable capacity compressor is generally provided in a crank chamber in which a part of the refrigerant having the discharge pressure Pd discharged from the discharge chamber is hermetically formed. The pressure Pc in the crank chamber is controlled by introducing the pressure and controlling the introduction amount. It is known that the amount of refrigerant introduced into the crank chamber is controlled according to the suction pressure Ps of the suction chamber, for example. That is, the control valve for the variable capacity compressor senses the suction pressure Ps and controls the flow rate of the refrigerant at the discharge pressure Pd introduced from the discharge chamber into the crank chamber so that the suction pressure Ps is kept constant. Yes.

  For this reason, the control valve for the variable capacity compressor has a pressure sensing part that senses the suction pressure Ps and a valve part that controls the opening and closing of the passage leading from the discharge chamber to the crank chamber according to the suction pressure Ps sensed by the pressure sensing part. And. Furthermore, in a variable capacity compressor control valve in which the value of the suction pressure Ps when entering the variable capacity operation can be freely set from the outside, a solenoid capable of changing the set value of the pressure sensing unit by an external current is provided. I have.

  By the way, among the conventional control valves for variable capacity compressors that can be controlled externally, an electromagnetic clutch that transmits or interrupts the driving force to the engine between the engine and a rotary shaft provided with a swing plate. There is a control valve for controlling a so-called clutchless variable displacement compressor in which the engine and the rotary shaft are directly connected without using the engine (see, for example, Patent Document 1).

  This control valve has a valve portion that controls opening and closing of a passage from the discharge chamber to the crank chamber, a solenoid that generates electromagnetic force that causes the valve portion to act in a closing direction, and a suction pressure Ps that is higher than atmospheric pressure. The pressure-sensitive part that causes the valve part to act in the opening direction as the height decreases is arranged in this order. For this reason, when the solenoid is not energized, the valve portion is fully opened, and the pressure Pc in the crank chamber can be maintained at a pressure close to the discharge pressure Pd. Can be operated at a minimum capacity by tilting in a substantially right angle direction. This means that even if the engine and the rotating shaft are directly connected, the discharge capacity can be substantially reduced to zero, so that the electromagnetic clutch can be eliminated.

  However, in a conventional control valve for controlling a variable capacity compressor that does not require an electromagnetic clutch, the pressure-sensitive part and the valve part are arranged with a solenoid interposed therebetween, and the feeling of comparing the suction pressure Ps with the atmospheric pressure. Since the pressure portion is configured to guide the suction pressure Ps through the solenoid, the entire solenoid must be accommodated in the pressure chamber, and the solenoid portion must be designed in consideration of pressure resistance. Don't be.

  Therefore, the present applicant divides the plunger of the solenoid into two, the first plunger and the second plunger, and arranges a pressure-sensitive member such as a diaphragm or a bellows that senses the suction pressure Ps between them, and performs suction. A control valve for a variable displacement compressor having a configuration for isolating the pressure Ps from the atmospheric pressure at which the solenoid is disposed has been filed (Japanese Patent Application No. 2003-289581).

  In addition, the applicant accommodates one of the separated plungers and the core in the vacuum vessel, seals the opening of the vacuum vessel with a diaphragm, and uses the diaphragm to set the suction pressure Ps to a solenoid coil. An application has been filed for a control valve for a variable capacity compressor configured to be isolated from atmospheric pressure (Japanese Patent Application No. 2004-125532). Hereinafter, a specific configuration of the control valve for the variable capacity compressor will be described.

FIG. 2 is a cross-sectional view showing another example of the configuration of the variable displacement compressor control valve.
This control valve for a variable capacity compressor is provided with a valve portion that supplies a pressure Pc, which is controlled by receiving a discharge pressure Pd from the discharge chamber of the variable capacity compressor, toward the crank chamber, in the upper part of the figure. The valve portion includes a valve seat 101, a valve body 102 disposed on the downstream side against the valve seat 101, and a spring 103 that biases the valve body 102 in the valve closing direction. The valve body 102 is formed integrally with a shaft 104 having an outer diameter that is the same as the inner diameter of the valve hole, and is held by the body so as to be movable back and forth in the axial direction.

  A solenoid is arranged below the figure. The solenoid has a core 106 and a first plunger 107 disposed in the bottomed sleeve 105, and a second plunger 108 and a coil 109 disposed outside the bottomed sleeve 105. Between the two plungers 108, a pressure-sensitive part diaphragm 110 is provided so as to seal the open end of the bottomed sleeve 105. In the bottomed sleeve 105, a first plunger 107 is fixed to a shaft 111 disposed through the center of the core 106, and the shaft 111 attaches the first plunger 107 away from the core by a spring 112. Thus, the first plunger 107 is brought into contact with the inner surface of the diaphragm 110.

  A suction pressure Ps in the suction chamber of the variable capacity compressor is introduced into the space in which the second plunger 108 is disposed, and the suction pressure Ps is detected by the diaphragm 110. The second plunger 108 is also fixed to the end of the shaft 104 opposite to the side on which the valve body 102 is provided, and is further separated from the diaphragm 110 by a spring 113 having a larger load than the spring 103 of the valve. It is biased away. As a result, the shaft 104 is biased upward in the drawing, and when the variable displacement compressor control valve is not operating, the valve portion is maintained in a fully opened state as shown in the figure. Therefore, in this state, even if the rotary shaft of the variable capacity compressor is rotationally driven by the engine, the variable capacity compressor is operated with a minimum discharge capacity.

  Here, when a control current is supplied to the solenoid coil 109, the first plunger 107 and the second plunger 108 are magnetically coupled with the diaphragm interposed therebetween and behave as one plunger. The axial positions of the first plunger 107 and the second plunger 108 at this time define the valve lift of the valve portion, and the valve lift is set according to the control current to the coil 109. On the other hand, since the diaphragm 110 receives the suction pressure Ps, the diaphragm 110 is displaced in the axial direction according to the suction pressure Ps, and the displacement is transmitted to the valve body 102 via the second plunger 108 and the shaft 104. .

Therefore, the control valve for the variable capacity compressor controls the refrigerant having the discharge pressure Pd to a flow rate corresponding to the control current to the coil 109 and introduces the refrigerant having the pressure Pc into the crank chamber. Operates at a discharge capacity corresponding to the control current. In this state, when the suction pressure Ps increases, the diaphragm 110 is displaced downward in the figure, and when the suction pressure Ps decreases, the diaphragm 110 is displaced upward. Since the valve lift of the valve portion changes in accordance with the displacement of the diaphragm 110, the crank chamber pressure Pc is adjusted, so that the variable capacity compressor eventually has the suction pressure Ps set to the value set by the solenoid. Thus, the discharge capacity is controlled.
JP 2000-110731 (paragraph numbers [0010], [0044], FIG. 1)

  However, in the above control valve for a variable capacity compressor, the shaft formed integrally with the valve body serves as a guide function for the second plunger. Depending on the state of the spring that urges it in the axial direction when it moves in the axial direction, the second plunger is tilted and a couple is applied to the shaft held by the body, and the axial sliding property There is a problem that the valve body is not damaged and the valve body does not move smoothly.

  The present invention has been made in view of the above points, and provides a control valve for a variable capacity compressor with improved slidability and improved controllability of a shaft that transmits a change in suction pressure to a valve body. The purpose is to do.

  In the present invention, in order to solve the above-described problem, a pressure-sensitive member that divides the plunger of the solenoid into two of the first plunger and the second plunger and senses the suction pressure therebetween is arranged, and the pressure-sensitive member In the control valve for a variable capacity compressor, wherein the change in the suction pressure sensed by the second plunger is transmitted to the valve body via the shaft, the second plunger is moved away from the pressure sensitive member. There is provided a control valve for a variable capacity compressor, which is held by a spring urging the valve and is brought into contact with the shaft.

  According to such a control valve for a variable capacity compressor, the spring has a guide function of the second plunger, and the second plunger and the shaft are in contact with each other. As a result, even when the second plunger is attracted by the first plunger and moves in the axial direction during energization, even if the second plunger is inclined with respect to the axis, no couple is generated on the shaft due to the inclination. , Controllability can be improved.

  The control valve for a variable displacement compressor according to the present invention eliminates the guide function of the second plunger from the shaft that transmits the change in the suction pressure to the valve body, so that a suction force is generated by the solenoid, and the second plunger moves along the axis. Even if it is tilted when moving in the direction, there is no influence on the shaft, so there is an advantage that the controllability can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a central longitudinal sectional view showing a configuration of a control valve for a variable capacity compressor according to the present invention.
This control valve for a variable capacity compressor has a valve portion in the upper part of the figure. The valve portion constitutes a port 12 in which the side opening of the body 11 communicates with the discharge chamber of the variable capacity compressor and receives the discharge pressure Pd, and a strainer 13 is attached around the port 12. . The port 12 that receives the discharge pressure Pd communicates internally with a port 14 that is open at the top of the body 11, and the port 14 communicates with the crank chamber of the variable capacity compressor and is controlled by the crank chamber. The pressure Pc is derived.

  A valve seat 15 is formed integrally with the body 11 in the refrigerant passage where the port 12 and the port 14 communicate with each other inside the body 11. A valve body 16 is disposed so as to be capable of moving forward and backward in the axial direction so as to face from the side from which the pressure Pc of the valve seat 15 is derived. The valve body 16 is formed integrally with a shaft 17 that extends downward through the valve hole and is held by the body 11 so as to be movable forward and backward in the axial direction. A discharge pressure Pd from the discharge chamber is introduced into a small diameter portion connecting the valve body 16 and the shaft 17. The outer diameter of the shaft 17 is the same as the inner diameter of the valve hole constituting the valve seat 15, and the pressure receiving area of the valve body 16 and the pressure receiving area of the shaft 17 are the same. As a result, the force that the discharge pressure Pd acts on the valve body 16 upward in the figure is canceled by the force that acts on the shaft 17 downward in the figure, and the control of the valve portion is not affected by the high discharge pressure Pd. I am doing so.

The valve body 16 is biased in the valve closing direction by a spring 18, and the load of the spring 18 is adjusted by an adjustment screw 19 screwed into the port 14.
Further, a port 20 is formed below the body 11 in the drawing so as to communicate with the suction chamber of the variable capacity compressor and receive the suction pressure Ps.

  The lower end of the body 11 is fixed by press-fitting to a body 21 made of a magnetic material that constitutes a part of the solenoid. In the body 21, the 2nd plunger 22 which is one of the plungers which the solenoid divided | segmented is arrange | positioned. The second plunger 22 is provided with a hole having an inner diameter sufficiently larger than the outer diameter of the shaft 17 at the center of the upper end surface in the figure, and the axis of the second plunger 22 in the state where there is almost no clearance from the body 11 at the bottom of the hole. The lower end surface of the shaft 17 held so as to be able to advance and retreat in the direction is brought into contact. The lower end surface of the shaft 17 is formed in an arc shape in cross section, and even if the angle of contact with the bottom of the hole is not exactly right, the second plunger 22 moves up and down to generate couple force on the shaft 17. I don't want to do that. The second plunger 22 is also formed in a T-shaped cross section, and the lower surface of the flange portion 23 in the drawing is opposed to the upper surface of the body 21 in the drawing. Thereby, when energization of the solenoid is started, a suction force in the axial direction is generated between the opposed surfaces of the flange portion 23 and the body 21 to help the valve portion move quickly in the valve closing direction. The second plunger 22 is further urged upward in the figure by a spring 24 disposed between the stepped portion formed in the body 21. The spring 24 has a larger load than the spring 18 that urges the valve body 16 in the valve closing direction, and when the solenoid is not energized, the second plunger 22 The shaft 17 can be pushed up until it abuts against the ceiling of the room communicating with 20, and the valve body 16 can be maintained in its fully open position. The spring 24 also holds a portion below the flange portion 23 of the second plunger 22 and serves as a guide function for the second plunger 22.

  Below the second plunger 22 in the figure, the pressure sensitive part and the remaining components of the solenoid are arranged. That is, below the second plunger 22 in the figure, a bottomed sleeve 25 forming a vacuum container accommodates a first plunger 26, a core 27, and a spring 28, which are the other plungers of the solenoid, and a bottomed sleeve. An assembly in which 25 openings are sealed with a metal diaphragm 29 is disposed, and a case 31 integral with the body 21 is formed outside the bottomed sleeve 25 to form a coil 30 and a yoke for forming a magnetic circuit. And a handle 32 are arranged.

  In the bottomed sleeve 25, a core 27 is fixed by press-fitting, and a first plunger 26 is disposed on the valve portion side so as to be movable forward and backward in the axial direction. The first plunger 26 is fixed by press-fitting to one end of a shaft 33 extending in the axial direction at the center of the core 27, and the other end of the shaft 33 is slidably disposed in the core 27. It is supported. A retaining ring 35 is fitted in the middle of the shaft 33, and a spring receiving portion 36 is provided so that the upward movement of the figure is restricted by the retaining ring 35. The spring receiving portion 36 and the bearing portion are provided. A spring 28 is disposed between the spring 34 and the spring 34. The first plunger 26 is urged by the spring 28 through the shaft 33 in a direction away from the core 27. The spring 28 is deformed inward by pushing the bottom of the bottomed sleeve 25, thereby changing the position of the bearing 34 in the axial direction, adjusting the load of the spring 28, and setting the control valve for the variable capacity compressor. The value is adjusted.

  The bottomed sleeve 25 in which the first plunger 26 and the core 27 are accommodated is sealed by welding a diaphragm 29 to a flange portion formed at the open end thereof, whereby an airtight state in which the inside is maintained in a vacuum state. The assembly is configured.

  In the above configuration, the body 21, the case 31, and the handle 32 are formed of a magnetic material and serve as a yoke in the magnetic circuit of the solenoid, and the lines of magnetic force generated by the coil 30 are the case 31, the body 21, The magnetic circuit including the two plungers 22, the first plunger 26, the core 27, and the handle 32 is passed.

  The illustrated state of the control valve for the variable capacity compressor indicates a state where the solenoid is not energized and the suction pressure Ps is high, that is, the state where the air conditioner is not operating. Since the suction pressure Ps is high, the diaphragm 29 is displaced downward in the figure against the load of the spring 28, and the first plunger 26 is brought into contact with the core 27. On the other hand, since the second plunger 22 is biased upward in the drawing so as to be separated from the diaphragm 29 by the spring 24, the valve body 16 is biased to its fully open position via the shaft 17. Therefore, in this state, even if the rotary shaft of the variable capacity compressor is rotationally driven by the engine, the variable capacity compressor is operated with a minimum discharge capacity.

  Here, when the maximum control current is supplied to the solenoid coil 30 as when the automotive air conditioner is activated, the first plunger 26 is pushed downward in the figure by the high suction pressure Ps. Since it is in contact with the core 27, it remains in the same position even if it is in a suction state with the core 27. Therefore, at this time, the first plunger 26 and the core 27 behave like a fixed iron core, and the first plunger 26 sucks the second plunger 22 against the urging force of the spring 24 via the diaphragm 29. The second plunger 22 is sucked and brought into contact with the diaphragm 29 to move downward in the drawing, and along with this, the valve body 16 is pushed down by the spring 18 and is seated on the valve seat 15. Fully closed. As a result, the passage from the discharge chamber to the crank chamber is blocked, so that the variable capacity compressor quickly shifts to the maximum capacity operation. At this time, since the second plunger 22 is simply in contact with the shaft 17 and is not restrained by the shaft 17, the second plunger 22 moves while being inclined according to the state of the spring 24 guiding the second plunger 22. Even if an attempt is made, a couple of force is not applied to the shaft 17, and the slidability in the axial direction is not impaired.

  When the variable capacity compressor continues to operate at the maximum capacity and the suction pressure Ps in the suction chamber becomes sufficiently low, the diaphragm 29 detects the suction pressure Ps and tries to move upward in the figure. At this time, if the control current supplied to the coil 30 of the solenoid is reduced according to the set temperature of the air conditioning, the second plunger 22 and the first plunger 26 are integrated in the adsorbed state, and the suction pressure Ps and the spring 18, It moves upward in the figure to a position where the load of 24 and 28 and the suction force of the solenoid are balanced. As a result, the valve body 16 is pushed up by the second plunger 22 and is separated from the valve seat 15 and set to a predetermined opening degree. Therefore, the refrigerant having the discharge pressure Pd is controlled to a flow rate corresponding to the opening degree and is introduced into the crank chamber, and the variable capacity compressor shifts to an operation with a capacity corresponding to the control current.

  When the control current supplied to the solenoid coil 30 is constant, the diaphragm 29 senses the suction pressure Ps by the absolute pressure and controls the valve lift of the valve portion. For example, when the refrigeration load is increased and the suction pressure Ps is increased, the first plunger 26 is displaced downward in the figure, so that the valve body 16 is also moved downward to reduce the valve lift, and the variable capacity compressor. Operates to increase the discharge capacity. Conversely, when the refrigeration load is reduced and the suction pressure Ps is reduced, the first plunger 26 is displaced upward in the figure to increase the valve lift, so that the variable capacity compressor reduces the discharge capacity. Operate. In this way, the control valve for the variable capacity compressor controls the discharge capacity of the variable capacity compressor so that the suction pressure Ps becomes a value set by the solenoid.

  As mentioned above, although this invention was explained in full detail about the suitable embodiment, this invention is not limited to this embodiment. For example, in the above embodiment, the first plunger 26 is accommodated in the vacuum container and the suction pressure Ps is detected by the absolute pressure. However, the portion accommodating the first plunger 26 is opened to the atmosphere. The present invention can be similarly applied to a control valve for a variable displacement compressor that compares the suction pressure Ps with the atmospheric pressure. Further, in the above embodiment, the pressure sensitive part is configured by a diaphragm, but may be configured by a bellows.

It is a center longitudinal cross-sectional view which shows the structure of the control valve for variable capacity compressors by this invention. It is sectional drawing which shows the other structural example of the control valve for variable capacity compressors.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Body 12 Port 13 Strainer 14 Port 15 Valve seat 16 Valve body 17 Shaft 18 Spring 19 Adjustment screw 20 Port 21 Body 22 2nd plunger 23 Flange part 24 Spring 25 Bottomed sleeve 26 First plunger 27 Core 28 Spring 29 Diaphragm 30 Coil 31 Case 32 Handle 33 Shaft 34 Bearing 35 Retaining Ring 36 Spring Bearing

Claims (3)

The solenoid plunger is divided into a first plunger and a second plunger, and a pressure-sensitive member for detecting the suction pressure is disposed between them, and the change in the suction pressure sensed by the pressure-sensitive member is determined by the pressure-sensitive member. In the control valve for a variable capacity compressor, wherein the second plunger is transmitted to the valve body via the shaft,
A control valve for a variable capacity compressor, wherein the second plunger is held by a spring that biases the second plunger in a direction away from the pressure-sensitive member, and is brought into contact with the shaft.   In the second plunger, a hole having an inner diameter larger than the outer diameter of the shaft is recessed in the center of the surface facing the shaft, and the end surface of the shaft is in contact with the bottom of the hole. The control valve for a variable capacity compressor according to claim 1. The control valve for a variable capacity compressor according to claim 2, wherein the shaft has a surface in contact with the bottom of the hole formed in a circular arc shape.

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