JP2011043102A - Control valve for variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control valve for a variable displacement compressor which can control dependence on high pressure and which can secure stable control characteristics. <P>SOLUTION: In a control valve of a certain mode, since the inner diameter D1 of a valve hole 14 is made smaller than the effective pressure receiving diameter D3 of an operation rod 18 by a predetermined amount (D1<D3), the control characteristics can be obtained which controls dependence on high pressure where intake pressure becomes higher because of a change in discharge pressure. That is to say, since as the discharge pressure becomes higher, the force in the valve-closing direction exerted on a valve body 16 becomes greater, the rise in the intake pressure is controlled. Moreover, since the control valve for the variable displacement compressor has a constitution that the effective pressure receiving diameter of the operation rod 18 is realized by an O-ring 21, the O-ring 21 can be inserted while being deformed when the operation rod 18 is incorporated into a body 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control valve suitable for controlling the discharge capacity of a variable capacity compressor used in an automotive air conditioner.

  In general, an air conditioner for an automobile compresses the refrigerant flowing through the refrigeration cycle and discharges it as a high-temperature / high-pressure gas refrigerant, a condenser that condenses the gas refrigerant, and adiabatic expansion of the condensed liquid refrigerant. And an expansion device that converts the refrigerant into a low-temperature and low-pressure refrigerant, an evaporator that exchanges heat with the air in the vehicle interior by evaporating the refrigerant, and the like. The refrigerant evaporated in the evaporator is returned to the compressor and circulates in the refrigeration cycle.

  As this compressor, a variable capacity compressor (also simply referred to as “compressor”) capable of varying the refrigerant discharge capacity is used so that a constant cooling capacity is maintained regardless of the engine speed. In this compressor, a piston for compression is connected to a swing plate attached to a rotary shaft that is driven to rotate by an engine, and the discharge amount of the refrigerant is changed by changing the stroke of the piston by changing the angle of the swing plate. adjust. The angle of the swing plate can be continuously changed by introducing a part of the discharged refrigerant into the sealed crank chamber and changing the balance of pressure applied to both surfaces of the piston. The pressure in the crank chamber (hereinafter referred to as “crank pressure”) Pc is a variable displacement compressor control valve (simply provided between the discharge chamber and the crank chamber of the compressor or between the crank chamber and the suction chamber). It is also controlled by “control valve”).

  As such a control valve, for example, there is a valve that controls the crank pressure Pc by adjusting the amount of refrigerant introduced into the crank chamber in accordance with the suction pressure Ps. The control valve senses and displaces the suction pressure Ps, a valve unit that controls opening and closing of a passage that leads to the crank chamber from the discharge chamber by receiving the driving force of the pressure sensing unit, and a set value of the pressure sensing unit And a solenoid that can be changed by an external current. Such a control valve opens and closes the valve portion so that the suction pressure Ps is maintained at a set pressure set by an external current. In general, since the suction pressure Ps is proportional to the refrigerant temperature at the evaporator outlet, freezing or the like of the evaporator can be prevented by maintaining the set pressure at a predetermined value or higher. Also, when the engine load of the vehicle is large, the solenoid is turned off to fully open the valve unit, the crank pressure Pc is increased, and the swing plate is made substantially perpendicular to the rotating shaft, thereby minimizing the compressor. It can be operated at capacity.

  By the way, such a control valve is configured to realize accurate control of the crank pressure Pc by reducing the influence of the discharge pressure Pd having a high pressure and a large pressure fluctuation (for example, Patent Document 1). reference). This control valve has a valve seat in a refrigerant passage formed between a port communicating with the discharge chamber and a port communicating with the crank chamber in the body, and a port communicating with the crank chamber with respect to the valve seat. A valve element is arranged so as to be freely contacted and separated from the side. Further, a pressure-sensitive piston penetrating the valve hole is integrally formed in the valve body (hereinafter, the integrally formed member is referred to as “valve rod” for convenience). In this control valve, the pressure-sensitive piston has almost the same outer diameter as the inner diameter of the valve hole, and the pressure-sensitive piston receives the discharge pressure Pd in the valve closing direction. The receiving pressure area is almost equal. As a result, the force acting on the valve element in the valve opening direction and the force acting on the pressure sensitive piston in the valve closing direction are substantially canceled as the force due to the discharge pressure Pd.

  However, while the valve body and the pressure-sensitive piston are integrally provided as a valve rod in this way, the valve body is formed larger than the valve hole. Therefore, when the valve rod is incorporated in the body of the control valve, It is necessary to insert into the body through the valve hole from the pressure piston side. Therefore, although it is almost the same, the inner diameter of the valve hole is inevitably larger than the outer diameter of the pressure-sensitive piston in terms of configuration. That is, since the effective pressure receiving area of the valve body is larger than the effective pressure receiving area of the pressure sensitive piston, the discharge pressure Pd acts in the valve opening direction of the valve body. As a result, the higher the discharge pressure Pd, the higher the refrigerant flow rate introduced into the crank chamber and the higher the crank pressure Pc. The higher the crank pressure Pc, the higher the suction pressure Ps. Occurs. In this high pressure dependent state, it becomes difficult to accurately maintain the suction pressure Ps at the set pressure.

  In order to solve such a problem, a technique for realizing a structure capable of reducing the high-pressure dependence in the process of assembling the valve rod to the body has also been proposed (see, for example, Patent Document 2). Specifically, the technology to reduce the opening area of the valve hole by coining etc. when assembling the valve rod to the body, the valve body and the pressure sensitive piston are configured separately, and the small diameter tip of the pressure sensitive piston A technique is disclosed in which a valve rod is joined from the opposite side after the valve is inserted into the valve hole. By such a method, the inner diameter of the valve hole can be made smaller than the outer diameter of the pressure-sensitive piston, and an increase in the suction pressure Ps can be suppressed even when the discharge pressure Pd increases. That is, the suction pressure Ps can be maintained at the set pressure regardless of the discharge pressure Pd by suppressing the problem of high pressure dependence.

JP 2005-61253 A JP 2008-267203 A

  However, coining is generally performed in order to match the shape of the contact surface between the valve body and the valve seat in order to ensure valve closing performance, and is not based on large plastic deformation. If the valve hole is deformed so as to be intentionally reduced in this way, the valve body or the valve seat may be greatly deformed in some cases, and the dimensional accuracy may be lowered. On the other hand, in the configuration in which the valve body and the pressure-sensitive piston are joined later, there is a possibility that the valve closing performance is deteriorated due to individual dimensional errors or assembly errors of both.

  The present invention has been made in view of such problems, and its main purpose is to suppress high-pressure dependence and ensure stable control characteristics with a simple configuration while ensuring assembly accuracy in a control valve for a variable displacement compressor. There is to be able to do it.

  In order to solve the above problems, a control valve for a variable capacity compressor according to an aspect of the present invention is a variable capacity compressor that controls a flow rate of refrigerant introduced from a discharge chamber into a crank chamber to change a discharge capacity of the variable capacity compressor. In the machine control valve, a crank pressure chamber into which the crank pressure of the crank chamber is introduced from one end side, a discharge pressure chamber into which the discharge pressure of the discharge chamber is introduced, and a pressure sensing chamber into which the sensed pressure is introduced are provided, Furthermore, the body is provided with a valve hole that connects the discharge pressure chamber and the crank pressure chamber, and a guide hole that connects the discharge pressure chamber and the pressure sensing chamber, and is attached to the opening end of the valve hole from the crank pressure chamber side. The valve body that opens and closes the valve section, and the suction pressure or crank pressure of the suction chamber are detected as the detected pressure, and when the detected pressure becomes lower than the set pressure, a force that acts on the valve body in the valve opening direction is sensed. Pressing part A solenoid that applies a solenoid force in the valve closing direction corresponding to the set pressure to the valve body, and a valve body that is slidably inserted into the guide hole and that passes through the valve hole. An actuating rod capable of transmitting the received solenoid force to the valve body, and a seal member that is interposed between the actuating rod and the guide hole and restricts refrigerant leakage from the discharge pressure chamber to the pressure sensing chamber.

  The guide hole has an inner diameter that is equal to or smaller than the inner diameter of the valve hole and a sliding portion that slidably supports the operating rod, and an enlarged diameter that is formed at the opening end on the discharge pressure chamber side and has a larger inner diameter than the valve hole. Part. The seal member is made of a flexible annular body that is externally inserted into the operating rod, and its outer peripheral surface is slidably disposed on the enlarged diameter portion of the guide hole, and operates at a position corresponding to the enlarged diameter portion. The pressure receiving part of the rod is formed.

  According to this aspect, the valve body is integrally provided on one end side of the operating rod, and the seal member is provided so as to be externally inserted at a predetermined position of the operating rod. The operating rod is directly supported while sliding on the sliding portion of the guide hole, but is indirectly supported on the high pressure side while sliding on the enlarged diameter portion of the guide hole via the seal member. In such a configuration, the seal member constitutes the pressure receiving portion of the operating rod, and the enlarged diameter portion where the pressure receiving portion is located has a larger inner diameter than the valve hole, so that the discharge pressure acts on the valve body in the valve closing direction. It becomes like this. That is, even if the discharge pressure increases, a force acts in a direction in which the valve opening decreases, and the crank pressure and thus the suction pressure are prevented from increasing. As a result, it becomes possible to suppress the dependence on high pressure and secure stable control characteristics. In addition, since the flexible seal member forms a large-diameter pressure receiving portion, when the operating rod is incorporated into the body, the seal member is bent inward, the valve hole is passed through, and the guide hole is inserted. Can do. That is, it is not necessary to divide the actuating rod and assemble it later, or to deform the valve hole later, so that the dimensional accuracy and assembling accuracy of the control valve can be ensured even after the actuating rod is assembled.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress a high voltage | pressure dependence with a simple structure and to ensure the stable control characteristic, ensuring the assembly | attachment precision in the control valve for variable capacity compressors.

It is sectional drawing which shows the structure of the control valve which concerns on embodiment. It is the A section expanded sectional view of FIG. It is a figure showing the effect by embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, for the sake of convenience, the positional relationship between the structures may be expressed as upper and lower with reference to the illustrated state.
FIG. 1 is a cross-sectional view illustrating a configuration of a control valve according to an embodiment.
The control valve 1 is incorporated in a variable capacity compressor (hereinafter simply referred to as “compressor”) that constitutes a refrigeration cycle of an automotive air conditioner (not shown). This refrigeration cycle compresses the refrigerant into a high-temperature / high-pressure gas refrigerant and discharges it, a condenser that condenses the gas refrigerant, and adiabatic expansion of the condensed liquid refrigerant makes it a low-temperature / low-pressure refrigerant. An expansion device, an evaporator for exchanging heat with the passenger compartment air by evaporating the refrigerant, and the like are provided. For example, alternative chlorofluorocarbon (HFC-134a) is used as the refrigerant, but a refrigerant having a high operating pressure such as carbon dioxide may be used. In that case, an external heat exchanger such as a gas cooler may be arranged in the refrigeration cycle instead of the condenser.

  The control valve 1 is configured as a so-called closing control valve that controls a flow rate of refrigerant introduced from the discharge chamber into the crank chamber by disposing a valve portion in a refrigerant passage that connects the discharge chamber of the compressor and the crank chamber. ing. An orifice or the like for allowing the refrigerant in the crank chamber to leak into the suction chamber is also provided between the crank chamber and the suction chamber, but illustration and detailed description thereof are omitted.

  The control valve 1 includes a valve body 2 having a valve portion therein, and a solenoid 3 that is integrally assembled with the valve body 2 to open and close the valve portion. The valve body 2 includes a stepped cylindrical body 10 in which a refrigerant passage is formed. A port 11 is provided on the side of the body 10 to receive a discharge pressure Pd in communication with a discharge chamber of a compressor (not shown). That is, the internal space provided with the port 11 forms a discharge pressure chamber 61 into which the discharge pressure Pd is introduced. The port 11 communicates internally with a port 12 opened at the top of the body 10. The port 12 communicates with a crank chamber of the compressor, and derives a pressure Pc (referred to as “crank pressure”) controlled via a valve portion. That is, the internal space provided with the port 12 forms a crank pressure chamber 62 into which the crank pressure Pc is introduced. Around the port 11 of the body 10, a strainer 63 including a filter that suppresses foreign matter such as metal powder contained in the discharge refrigerant from flowing into the discharge pressure chamber 61 is provided. In addition, a strainer 64 including a filter that suppresses foreign matter contained in the refrigerant introduced from the crank chamber from flowing into the crank pressure chamber 62 is provided around the port 12 of the body 10.

  A valve hole 14 is provided in the refrigerant passage communicating the port 11 and the port 12. A valve seat 15 is formed integrally with the body 10 at the opening end of the valve hole 14 on the crank pressure chamber 62 side. A valve body 16 is disposed so as to face the valve seat 15 from the crank pressure chamber 62 side. Further, a guide hole 17 is formed so as to face the valve hole 14 along the axis of the body 10, and a long operating rod 18 is slidably inserted into the guide hole 17. A diameter-reduced portion 19 whose outer diameter is reduced by one step is formed on one end side of the operating rod 18. The diameter-reduced portion 19 extends through the valve hole 14 to the crank pressure chamber 62, and a disc-like valve body 16 is provided at the tip thereof. The operating rod 18 and the valve body 16 are obtained by integrally forming a stainless steel tubular member by cutting. The body 10 is made of a metal material (such as brass) that is softer than the valve body 16 and the operating rod 18. The valve body 16 operates so as to be able to contact with and separate from the valve seat 15 along the axial direction together with the operating rod 18. The operating rod 18 is formed with a communication passage 65 extending therethrough in the axial direction.

  The guide hole 17 includes a sliding portion 66 that slidably supports the lower half portion of the operating rod 18 and a diameter-enlarged portion 68 having a predetermined length that is expanded by one step toward the discharge pressure chamber. As will be described later, the sliding portion 66 has an inner diameter smaller than that of the valve hole 14, and the enlarged diameter portion 68 has an inner diameter larger than that of the valve hole 14. An annular groove 20 having a predetermined depth is formed at a position in the vicinity of the discharge pressure chamber 61 in the operating rod 18, and an O-ring 21 for sealing is externally fitted. Thereby, the leakage of the refrigerant from the discharge pressure chamber 61 to the sliding portion 66 is restricted. The O-ring 21 functions not only as such a sealing function but also as a pressure receiving portion of the operating rod 18, details of which will be described later.

  A spring receiving member 22 is screwed into the upper end opening of the body 10, and between the spring receiving member 22 and the valve body 16 as an urging means for urging the valve body 16 in the valve closing direction. A spring 23 is interposed. The load of the spring 23 can be adjusted by the screwing amount of the spring receiving member 22 into the body 10.

  Below the body 10 is formed a port 24 that communicates with the suction chamber of the compressor and receives the suction pressure Ps. That is, the internal space provided with the port 24 forms a suction pressure chamber 69 (corresponding to a “pressure sensing chamber”) into which the suction pressure Ps is introduced.

  The valve body 2 and the solenoid 3 are connected via a cylindrical connecting member 25 made of a magnetic material. That is, the lower end portion of the body 10 is press-fitted into the upper end portion of the connection member 25, and the upper end portion of the case 30 of the solenoid 3 is press-fitted into the lower end portion of the connection member 25.

  The solenoid 3 includes a case 30 that also functions as a yoke, a mold coil 31 disposed in the case 30, a bottomed sleeve 32 inserted into the mold coil 31, and a core fixed in the bottomed sleeve 32. 33 and a core 33 and a plunger 34 arranged to face each other in the axial direction. The mold coil 31 includes a cylindrical bobbin 41 and an electromagnetic coil 42 wound around the bobbin 41. A ring-shaped plate 49 made of a magnetic material is molded at the lower end of the mold coil 31. The plate 49 forms a magnetic circuit together with the case 30. The lower end portion of the case 30 is crimped to fix the mold coil 31, and the upper end portion is crimped to be fixed to the connection member 25.

  The plunger 34 is composed of two plungers divided with the diaphragm 50 in between. The first plunger 51, which is one of them, is disposed inside the mold coil 31, and the other second plunger 52 is connected to the body 10, the connection member 25, and the like. It is arranged in the space surrounded by. The diaphragm 50 is a flexible pressure-sensitive member that constitutes a pressure-sensitive portion, and is configured by stacking a plurality of polyimide films. In the modification, a metal diaphragm may be employed as the diaphragm 50.

  A recess 36 is formed at the center of the upper surface of the second plunger 52, and the lower end surface of the actuating rod 18 is supported by a flat surface at the center so as to be able to contact and separate. In the state shown in the drawing, since the second plunger 52 abuts against the operating rod 18 and seals the lower end opening thereof, the communication between the crank pressure chamber 62 and the suction pressure chamber 69 is blocked. When the plunger 52 is separated from the operating rod 18, the refrigerant is allowed to be led from the crank pressure chamber 62 to the suction pressure chamber 69 via the communication path 65. Further, a flange portion 38 extending radially outward is provided at the upper end portion of the second plunger 52, and the lower surface of the flange portion 38 is made to correspond to the upper surface of the connection member 25. Thereby, when the solenoid 3 is energized, a suction force in the axial direction is generated between the flange portion 38 and the connection member 25 so that the valve body 16 can move quickly in the valve closing direction. The second plunger 52 is biased upward by a spring 55 (corresponding to a “biasing member”) interposed between the second plunger 52 and a step formed in the connecting member 25. The spring 55 has a larger spring force than the spring 23 that biases the valve body 16 in the valve closing direction.

  Below the second plunger 52, an assembly in which the first plunger 51, the core 33 and the spring 56 are accommodated in the bottomed sleeve 32 and the opening thereof is sealed with the diaphragm 50 is disposed. That is, a flange portion 70 extending radially outward is provided at the upper end opening of the bottomed sleeve 32, and an annular clamping plate is sandwiched between the flange portion 70 and the outer peripheral edge portion of the diaphragm 50. 72 is joined (peripheral welding). The assembly is fixed to the connection member 25 and thus the body 10 by inserting the upper end of the diaphragm 50 into the lower end opening of the connection member 25 and press-fitting the annular member 74 from below. Is done. A sealing O-ring 75 is interposed between the lower end surface of the connecting member 25 and the sandwiching plate 72.

  A molded coil 31 and a case 30 made of a magnetic material are disposed outside the bottomed sleeve 32. The bottomed sleeve 32 has a bottomed cylindrical shape, and is configured by welding an upper half 45 made of a nonmagnetic material and a lower half 46 made of a magnetic material. In the bottomed sleeve 32, the core 33 is press-fitted on the lower half portion 46 side, and the first plunger 51 is disposed on the upper half portion 45 side so as to be movable back and forth in the axial direction.

  The first plunger 51 is press-fitted into one end of a shaft 57 that extends in the axial direction around the center of the core 33. The other end of the shaft 57 is supported by a bearing member 58 disposed in the core 33. A retaining ring 59 is fitted in the middle of the shaft 57, and a spring receiver 60 is provided so that upward movement is regulated by the retaining ring 59. A spring 56 that biases the first plunger 51 in a direction away from the core 33 via the shaft 57 is interposed between the spring receiver 60 and the bearing member 58. The load of the spring 56 can be adjusted by, for example, deforming the bottom portion of the bottomed sleeve 32 by pushing it from the outside and changing the position of the bearing member 58 in the axial direction.

  A handle 39 is provided at the lower end opening of the case 30 so as to seal the inside of the solenoid 3 from below. The handle 39 also functions as a connector portion that exposes one end of the terminal 76 connected to the electromagnetic coil 42. The terminal 76 is connected to an external power source (not shown). In order to prevent intrusion of foreign matter from the outside, a sealing O-ring 77 is disposed between the bottomed sleeve 32 and the handle 39, and a sealing O-ring 77 is also provided between the handle 39 and the case 30. An O-ring 78 is provided. Further, when the control valve 1 is attached to a housing of a compressor (not shown), a sealing O-ring 80 is externally fitted to the lower end portion of the case 30 in order to prevent foreign matter from entering the mounting hole of the housing. Are combined.

FIG. 2 is an enlarged cross-sectional view of a portion A in FIG.
The valve portion of the present embodiment is configured such that the inner diameter D1 of the valve hole 14 is slightly larger than the outer diameter D2 of the operating rod 18 (D1> D2). Since the operating rod 18 is configured to be slidable on the sliding portion 66, the outer diameter D <b> 2 of the operating rod 18 is substantially equal to the inner diameter of the sliding portion 66 of the guide hole 17. On the other hand, the inner diameter D3 of the enlarged diameter portion 68 of the guide hole 17 is configured to be slightly larger than the inner diameter D1 of the valve hole 14 (D1 <D3). Since the O-ring 21 is configured to be slidable on the enlarged diameter portion 68, the outer diameter of the O-ring 21 is substantially equal to the inner diameter D3 of the enlarged diameter portion 68. In addition, as a method of making the inner diameter of the enlarged diameter portion 68 larger than the valve hole 14, for example, the machining radius is set in the process of machining the valve hole 14, the enlarged diameter portion 68, and the sliding portion 66 one after another by means of a centering process using a lathe. The method of changing is mentioned. Due to the magnitude relationship between the outer diameter and the inner diameter, the dimensional accuracy and assembly accuracy of the operating rod 18 can be kept high, and the assembly of the operating rod 18 can be realized easily and at low cost.

  That is, since the outer diameter D2 of the operating rod 18 is smaller than the inner diameter D1 of the valve hole 14, the operating rod 18 can be assembled so as to be inserted into the body 10 from the crank pressure chamber 62 side. Referring to FIG. 1, with the O-ring 21 attached to the operating rod 18, the valve hole 14 is inserted into the crank pressure chamber 62 from the end opposite to the valve body 16 (lower end in the figure). Through the guide hole 17. Since the outer diameter of the O-ring 21 is larger than the inner diameter of the valve hole 14, the O-ring 21 is caught by the valve hole 14 during the insertion process. However, since the O-ring 21 is elastically deformed inward, the valve hole 14 is It is possible to pass through. Since the opening end of the valve hole 14 has a tapered surface, the O-ring 21 can be smoothly passed. Since the O-ring 21 is elastically restored when passing through the valve hole 14, the O-ring 21 comes into close contact with the outer peripheral surface of the operating rod 18 on the inner side, and comes into contact with the enlarged diameter portion 68 on the outer side. That is, the actuating rod 18 is directly supported while the lower half of the actuating rod 18 slides on the sliding portion 66 and is indirectly supported while sliding on the enlarged diameter portion 68 via the O-ring 21 on the high pressure side. .

  With such a configuration, the effective diameter in the valve opening direction at which the discharge pressure Pd acts on the operating rod 18 is equal to the inner diameter D1 of the valve hole 14, and the effective diameter in the valve closing direction is equal to the inner diameter D3 of the expanded portion 68. . That is, the action of the discharge pressure Pd in the valve opening direction is reduced, and the valve portion is suppressed from becoming dependent on high pressure. As a result, stable valve characteristics can be ensured. In the present embodiment, the clearance between the enlarged diameter portion 68 of the guide hole 17 and the operating rod 18 is configured to be larger than the width of the filter mesh of the strainer 63. For this reason, the possibility that a small foreign matter that has passed through the strainer 63 is caught by the clearance and biting occurs is extremely low.

Returning to FIG. 1, the operation of the control valve of the present embodiment will be described.
In the control valve 1, when the solenoid 3 is not energized, that is, when the automobile air conditioner is not operating, no suction force acts between the core 33 and the plunger 34. Further, since the suction pressure Ps is high, the first plunger 51 that is in contact with the diaphragm 50 is displaced downward against the load of the spring 56, and the first plunger 51 is brought into contact with the core 33. On the other hand, since the second plunger 52 is urged upward by the spring 55 so as to be separated from the first plunger 51, the valve body 16 is urged to its fully open position via the operating rod 18. At this time, the refrigerant having the discharge pressure Pd introduced into the port 11 from the discharge chamber of the compressor passes through the fully opened valve portion and flows from the port 12 to the crank chamber. Therefore, the crank pressure Pc increases and the compressor operates at the minimum capacity.

  On the other hand, when the maximum control current is supplied to the electromagnetic coil 42 of the solenoid 3, such as when the automobile air conditioner is activated, the first plunger 51 resists the biasing force of the spring 55 via the diaphragm 50. Then, the second plunger 52 is sucked. The second plunger 52 moves downward by being sucked and brought into contact with the diaphragm 50, and accordingly, the valve body 16 is pushed down by the spring 23 and seated on the valve seat 15, and the valve portion is fully closed. It becomes a state. In addition, since the second plunger 52 is temporarily separated from the operating rod 18 by the suction force of the solenoid 3, the crank pressure chamber 62 and the suction pressure chamber 69 communicate with each other. As a result, the refrigerant in the crank chamber is led out from the port 24 to the suction chamber side through the crank pressure chamber 62, the communication passage 65, and the suction pressure chamber 69. That is, the passage from the discharge chamber to the crank chamber is blocked and the refrigerant in the crank chamber is released not only through the orifice but also through the control valve 1, so that the compressor can quickly shift to the maximum capacity operation. In the present embodiment, the mechanism for abutting or separating the second plunger 52 and the operating rod 18 in this manner constitutes an “opening / closing mechanism”.

  When the suction pressure Ps in the suction chamber becomes sufficiently low in this way, the diaphragm 50 senses the suction pressure Ps and is displaced upward, the second plunger 52 comes into contact with the operating rod 18 and the communication path 65 is blocked. For this reason, it is prevented that the crank pressure Pc decreases unnecessarily. At this time, if the control current supplied to the electromagnetic coil 42 of the solenoid 3 is reduced according to the set temperature of the air conditioning, the second plunger 52 and the first plunger 51 are integrated in the adsorbed state, and the suction pressure Ps and the spring are integrated. It moves upward to a position where the load of 23, 55, 56 and the suction force of the solenoid 3 are balanced. As a result, the valve body 16 is pushed up by the second plunger 52 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 introduced into the crank chamber, and the compressor shifts to an operation with a capacity corresponding to the control current.

  When the control current supplied to the electromagnetic coil 42 of the solenoid 3 is constant, the diaphragm 50 senses the suction pressure Ps and controls the valve opening. For example, when the refrigeration load increases and the suction pressure Ps increases, the valve body 16 is displaced downward together with the operating rod 18, the second plunger 52, the diaphragm 50, and the first plunger 51. The opening is reduced and the compressor operates to increase the discharge capacity. Conversely, when the refrigeration load decreases and the suction pressure Ps decreases, the valve body 16 is displaced upward to increase the valve opening, so that the compressor operates to reduce the discharge capacity. In this way, the control valve 1 controls the discharge capacity of the compressor so that the suction pressure Ps becomes the set pressure set by the solenoid 3.

  FIG. 3 is a diagram illustrating operational effects according to the embodiment. (A) shows the pressure characteristic of this embodiment, and (B) shows the pressure characteristic when the inner diameter of the valve hole is slightly larger than the effective pressure receiving diameter of the operating rod as a comparative example. In each figure, the horizontal axis indicates the discharge pressure Pd, and the vertical axis indicates the suction pressure Ps. And the change of the suction pressure Ps when the discharge pressure Pd is increased when I1 (0.26 A), I2 (0.52 A), and I3 (0.75 A) are applied as the control current is shown. .

  In the present embodiment, as described above, the inner diameter D1 of the valve hole 14 is configured to be smaller by a predetermined amount than the effective pressure receiving diameter D3 of the operating rod 18 (including the pressure receiving portion by the O-ring 21) (D1 <D3). Specifically, D1 = 3.8 mm, D2 = 3.7 mm, and D3 = 4 mm shown in FIG. On the other hand, in the comparative example, the diameter-expanded portion is not provided, and the inner diameter D1 of the valve hole is slightly larger than the effective pressure receiving diameter D2 = D3 of the operating rod (D1 <D2 = D3). Specifically, D1 = 3.8 mm and D2 = D3 = 3.7 mm shown in FIG. As a result, in the comparative example shown in FIG. 3B, the suction pressure Ps increases as the discharge pressure Pd increases. However, in the present embodiment shown in FIG. Control characteristics with reduced dependence are obtained. This is because, as the discharge pressure Pd increases, a force in the valve closing direction acts on the valve body 16 so that the increase in the suction pressure Ps is suppressed. Depending on the set pressure of the suction pressure Ps, that is, the value of the current supplied to the control valve 1, a control characteristic that makes the suction pressure Ps substantially constant can be obtained. It should be noted that how much the inner diameter D1 of the valve hole 14 is made smaller than the effective pressure receiving diameter D3 of the actuating rod 18 is appropriately set in consideration of the influence of the load by the spring 23, for example.

  As described above, in the control valve 1 of the present embodiment, the valve portion is prevented from becoming dependent on the high pressure by making the inner diameter D1 of the valve hole 14 smaller than the effective pressure receiving diameter D3 of the operating rod 18. it can. For this reason, the solenoid force which balances with the force by discharge pressure Pd in the control state of the control valve 1 can be made small. As a result, the solenoid 3 and thus the control valve 1 can be made compact. Further, since the effective pressure receiving diameter D3 of the actuating rod 18 is realized by the flexible O-ring 21, the actuating rod 18 and the valve body 16 are configured separately, or the valve hole 14 formed by the actuating rod 18 is formed. It is not necessary to perform coining or the like, and can be realized easily and at low cost. Further, since the O-ring 21 has flexibility, a vibration isolation effect of the operating rod 18 is also expected.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the technical idea of the present invention. Needless to say.

  In the above-described embodiment, the plunger 3 is exemplified as the solenoid 3. However, a solenoid composed of a single plunger such as the control valve shown in Patent Document 1 may be employed. In that case, for example, the shaft of the solenoid and the operating rod may be formed integrally.

  In the above-described embodiment, the diaphragm 50 as the pressure sensitive member is configured by stacking a plurality of polyimide films, but may be configured by other resin materials or metal thin plates such as beryllium copper and stainless steel. Alternatively, the pressure sensitive member may be constituted by a bellows or other flexible member.

  In the above embodiment, the inner diameter of the valve hole is made smaller than the effective pressure receiving diameter of the operating rod (the inner diameter of the enlarged diameter portion 68), but in order to exert the effect of canceling the discharge pressure Pd, It is preferable not to greatly differ. With respect to this point, it is preferable to set an appropriate difference in diameter in consideration of control characteristics representing the relationship between the discharge pressure Pd and the suction pressure Ps.

  In the above embodiment, the control valve 1 is configured as a so-called Ps sensing valve that performs capacity control so as to keep the suction pressure Ps of the variable capacity compressor at a set pressure. The method and control target are not limited to these. For example, a crank pressure Pc can be introduced from the port 24, and a so-called Pc sensing valve that performs capacity control to keep the crank pressure Pc at a set pressure can also be configured.

  In the above embodiment, the control valve 1 is shown as an example of a control valve that controls the flow rate of the refrigerant introduced from the discharge chamber of the variable capacity compressor into the crank chamber. You may comprise as a control valve to control.

  DESCRIPTION OF SYMBOLS 1 Control valve, 2 Valve body, 3 Solenoid, 10 Body, 14 Valve hole, 15 Valve seat, 16 Valve body, 17 Guide hole, 18 Actuation rod, 21 O-ring, 33 Core, 34 Plunger, 42 Electromagnetic coil, 50 Diaphragm 61 discharge pressure chamber, 62 crank pressure chamber, 65 communication passage, 66 sliding portion, 68 enlarged diameter portion, 69 suction pressure chamber.

Claims (5)

In a control valve for a variable capacity compressor that controls the flow rate of refrigerant introduced from the discharge chamber into the crank chamber to change the discharge capacity of the variable capacity compressor,
A crank pressure chamber into which the crank pressure of the crank chamber is introduced from one end side, a discharge pressure chamber into which the discharge pressure of the discharge chamber is introduced, a pressure sensing chamber into which a sensed pressure is introduced are provided, and further, the discharge pressure A body provided with a valve hole for communicating the chamber and the crank pressure chamber, and a guide hole for communicating the discharge pressure chamber and the pressure sensing chamber;
A valve body that opens and closes the valve portion by attaching to and detaching from the crank pressure chamber side to the opening end of the valve hole;
A pressure sensing unit that senses the suction pressure of the suction chamber or the crank pressure as the sensed pressure, and applies a force in the valve opening direction to the valve body when the sensed pressure becomes lower than a set pressure;
A solenoid that causes a solenoid force in a valve closing direction according to the set pressure to act on the valve body;
An operating rod that is slidably inserted into the guide hole and is provided with the valve body on one end side that penetrates the valve hole, and that can transmit the solenoid force received on the other end side to the valve body,
A seal member interposed between the actuating rod and the guide hole to regulate leakage of the refrigerant from the discharge pressure chamber to the pressure sensing chamber;
With
The guide hole is formed in a sliding portion having an inner diameter equal to or smaller than the inner diameter of the valve hole and slidably supporting the operating rod, and an opening end on the discharge pressure chamber side, and is larger than the valve hole. An enlarged diameter portion having an inner diameter,
The seal member is formed of a flexible annular body that is externally inserted into the operating rod, and an outer peripheral surface thereof is slidably disposed on a diameter-enlarged portion of the guide hole, and corresponds to the diameter-enlarged portion. A control valve for a variable capacity compressor, characterized in that a pressure receiving portion of the operating rod is formed. The valve body is integrally formed with the actuating rod;
The actuating rod is assembled such that an end opposite to the valve body is inserted into the guide hole from the crank pressure chamber side via the valve hole. 2. A control valve for a variable capacity compressor according to 1. When a refrigerant is introduced from the discharge chamber into the discharge pressure chamber, a filter that regulates the intrusion of foreign matter contained in the refrigerant is provided.
3. The variable capacity compression according to claim 1, wherein a clearance between the diameter-enlarged portion of the guide hole and the operating rod is configured to be larger than a width of the mesh of the filter. Control valve for machine. The pressure sensing chamber communicates with the suction chamber and is provided as a suction pressure chamber that introduces suction pressure as the sensed pressure, and communicates the crank pressure chamber and the suction pressure chamber so as to penetrate the operating rod. Possible communication paths,
The communication passage is opened at the start of driving of the solenoid to permit the refrigerant to be led out from the crank pressure chamber to the suction pressure chamber, while the communication passage is closed after the start of driving of the solenoid to close the crank pressure chamber. The control valve for a variable capacity compressor according to any one of claims 1 to 3, further comprising an opening / closing mechanism for restricting the derivation of the refrigerant into the suction pressure chamber. The solenoid includes a core fixed to the body, a plunger that transmits the driving force to the valve body while supporting the other end of the operating rod, and a magnetic circuit including the plunger and the core by energization. An electromagnetic coil to be generated,
The plunger is configured by arranging a first plunger facing the core and a second plunger supporting the other end of the operating rod in series in the axial direction,
A pressure-sensitive member that senses the suction pressure as the pressure-sensitive portion and a biasing member that biases the second plunger in the valve opening direction are disposed between the first plunger and the second plunger.
When the solenoid is energized, the first plunger and the second plunger operate integrally through the pressure-sensitive member, and when the solenoid is not energized, the second plunger is attached to the biasing member. It is configured to be separated from the first plunger by a force,
The second plunger is configured to abut against the end of the actuating rod opposite to the valve body and close the open end of the communication path, and at the start of driving of the solenoid, the second plunger is The control valve for a variable capacity compressor according to claim 4, wherein the communication passage is opened by being separated from the operating rod.

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