JP2006097673A - Control valve for variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control valve for a variable displacement compressor, capable of quickly restoring it to a prescribed discharge capacity without hunting even in a case of rapid fluctuation of rotation speed of the variable displacement compressor of high sensitivity. <P>SOLUTION: At a valve part 13 for controlling flow of refrigerant from a discharge chamber to a crank chamber based on differential pressure between discharge pressure Pd and suction pressure Ps, a pressure sensitive part 12 is provided on a high pressure port 18. As a pressure sensitive piston 19 having larger pressure bearing surface than a valve element 23 receives rapid change of the discharge pressure Pd, differential pressure generated between the discharge pressure Pd and pressure in a pressure regulating chamber 20 acts to the valve element 23 in the opposite direction to its opening/closing direction to temporarily slowing move of the valve element 23 that is opened/closed by differential pressure between the discharge pressure Pd and the suction pressure Ps. The variable displacement compressor of high sensitivity is thus restored to the prescribed discharge capacity without hunting. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control valve for a variable capacity compressor, and in particular, is mounted on a variable capacity compressor constituting a refrigeration cycle of an air conditioner for an automobile, and its discharge capacity is controlled by a differential pressure between the discharge pressure and the suction pressure. The present invention relates to a control valve for a variable capacity compressor.

  Since the compressor used for compressing the refrigerant in the refrigeration cycle of the air conditioner for automobiles uses the engine as a drive source, the rotational speed control cannot be performed. Therefore, in order to obtain an appropriate cooling capacity without being restricted by the engine speed, a variable capacity compressor capable of changing the compression capacity of the refrigerant is used.

  In such a variable capacity compressor, a compression piston is connected to a swing plate attached to a shaft that is rotationally driven by an engine, and the stroke of the compression piston is changed by changing the angle of the swing plate. The amount of refrigerant discharged is changed.

  The angle of the swing plate is continuously increased by introducing a part of the compressed refrigerant into the sealed crank chamber, changing the pressure of the introduced refrigerant, and changing the balance of pressure applied to both sides of the compression piston. Is changing.

  The pressure in the crank chamber is set between the discharge chamber and the crank chamber of the variable capacity compressor or between the crank chamber and the suction chamber to change the flow rate of the refrigerant introduced from the discharge chamber into the crank chamber, or from the crank chamber. A control valve for a variable capacity compressor, which is adjusted by changing the flow rate of the refrigerant led to the suction chamber, is known (for example, see Patent Document 1).

  The control valve for a variable displacement compressor described in Patent Document 1 has a valve portion that is disposed in a refrigerant passage between a discharge chamber and a crank chamber when the variable displacement compressor is mounted on a crank. A path through which the refrigerant flows from the discharge chamber to the suction chamber is formed through an orifice provided between the chamber and the suction chamber. The control valve for a variable capacity compressor includes a valve portion that is configured integrally with a valve body that receives the discharge pressure Pd in the valve opening direction and a piston rod that has substantially the same diameter as the valve hole on the back side of the valve body. The end face of the piston rod is configured to receive a suction pressure Ps in the valve closing direction and a solenoid load that sets a discharge capacity by an external signal. Therefore, in this control valve for a variable capacity compressor, since the discharge pressure Pd and the suction pressure Ps are received at both ends of the valve body and the piston rod having the same effective pressure receiving area, the differential pressure between them (Pd−Ps). The valve body opens and closes to control the flow rate of refrigerant flowing from the discharge chamber to the crank chamber.

  For example, when the rotational speed of the engine increases and the rotational speed of the variable capacity compressor increases and its discharge capacity increases, the discharge pressure Pd increases and the suction pressure Ps decreases and the differential pressure therebetween. (Pd−Ps) increases. Then, since the valve lift of the valve part operated by the differential pressure (Pd−Ps) increases in the control valve for the variable capacity compressor, the flow rate of refrigerant introduced into the crank chamber is increased, and the pressure Pc in the crank chamber is increased. Thus, the discharge capacity of the variable capacity compressor is lowered, and thereby the differential pressure (Pd−Ps) is controlled to be small. That is, the control valve for the variable capacity compressor controls the flow rate of the refrigerant introduced into the crank chamber so that the variable capacity compressor maintains the differential pressure (Pd−Ps) between the discharge pressure Pd and the suction pressure Ps at a predetermined value. ing. The predetermined value of the differential pressure can be set from the outside by the value of the current supplied to the solenoid.

A variable capacity compressor controlled by such a control valve for a variable capacity compressor has a differential pressure due to a change in the discharge capacity due to a change in the rotation speed of the variable capacity compressor due to a change in the engine speed. The pressure Pc in the crank chamber changes due to the change in (Pd−Ps), whereby the tilt angle of the swing plate changes, and the discharge capacity varies between the maximum and minimum. For example, when the differential pressure (Pd-Ps) is 0, such as at the time of startup, the variable capacity compressor is operating at the maximum capacity, and when the differential pressure (Pd-Ps) reaches a certain value, the capacity variable starts. However, the variable capacity compressor has individuality, and depending on the variable capacity compressor, there is a range in the value of the differential pressure (Pc−Ps) between the pressure Pc in the crank chamber and the suction pressure Ps when starting variable capacity. is there. This is due to the ease of movement of the swing plate of the variable capacity compressor, that is, the difference in sensitivity.
JP 2001-132650 A (paragraph numbers [0043] to [0045], FIG. 4)

  However, the variable capacity compressor with high sensitivity has a problem in that it reacts sensitively to sudden pressure changes of the discharge pressure Pd and the suction pressure Ps due to rapid fluctuations in the rotational speed, and hunting occurs.

  The present invention has been made in view of the above points, and causes hunting for a variable capacity compressor having high sensitivity even if there is a sudden pressure change due to a sudden change in engine speed. It is an object of the present invention to provide a control valve for a variable displacement compressor that can perform stable control without any problems.

  In the present invention, in order to solve the above problem, the flow rate of the refrigerant flowing from the discharge chamber to the crank chamber is controlled by sensing the differential pressure between the discharge pressure of the discharge chamber of the variable capacity compressor and the suction pressure of the suction chamber. In the control valve for a variable capacity compressor, in which the discharge capacity of the refrigerant is changed by the above, only a value proportional to the degree of the pressure change is detected by detecting a pressure change due to a sudden change in the rotational speed of the variable capacity compressor. There is provided a control valve for a variable capacity compressor, comprising a pressure-sensitive portion that slows the movement of the valve portion in the opening / closing direction.

  According to such a control valve for a variable capacity compressor, the pressure-sensitive part is insensitive to pressure changes due to a gradual change in the rotational speed of the variable capacity compressor and operates in the same manner as in the past, but suddenly Pressure change due to fluctuations in the number of revolutions, and the pressure sensing part senses and moves the valve part in the direction opposite to the opening and closing direction of the valve part by a value proportional to the degree of pressure change. Is dull. As a result, the variable displacement compressor with high sensitivity can quickly recover to a predetermined discharge capacity without causing an overshoot of a pressure change caused by a sudden change in the rotational speed. .

  In the control valve for a variable capacity compressor of the present invention, when the variable capacity compressor is subjected to a sudden change in the rotational speed, the pressure sensing unit senses a pressure change due to the change in the rotational speed, and determines the degree of the pressure change. Since the valve section is slowed in the opening and closing direction by a proportional value, it is possible to perform stable capacity control without hunting even when a highly sensitive variable capacity compressor is subjected to sudden fluctuations in the rotational speed. There is an advantage that you can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a central longitudinal sectional view schematically showing a control valve for a variable capacity compressor according to a first embodiment.

  The control valve 11 for the variable capacity compressor senses a pressure sensing unit 12 that senses a sudden pressure fluctuation of the discharge pressure Pd, and senses a differential pressure (Pd−Ps) between the discharge pressure Pd and the suction pressure Ps. A valve unit 13 for controlling the flow rate of the refrigerant flowing from the engine to the crank chamber and a solenoid 14 capable of setting a predetermined value of the differential pressure (Pd-Ps) to be controlled from the outside are arranged on the same axis. Has been.

  A cylinder 15 is formed in the upper part of the body 15 accommodating the pressure sensitive part 12 and the valve part 13, and the opening at the upper end is closed by a lid 17. A high pressure port 18 communicating with the discharge chamber when the variable capacity compressor control valve 11 is mounted on the variable capacity compressor is formed at a lower position of the cylinder 16 in the figure. A pressure-sensitive piston 19 is disposed in the cylinder 16 so as to be movable back and forth in the axial direction. A space for the pressure regulating chamber 20 is formed in the upper part of the cylinder 16 together with the body 15 and the lid 17. The pressure regulating chamber 20 communicates with the high pressure port 18 through a predetermined clearance between the cylinder 16 and the pressure sensitive piston 19. A hole is formed in the center of the bottom of the cylinder 16, and a cylindrical valve seat forming member 21 is press-fitted into the hole. The valve seat forming member 21 has a passage penetrating in the axial direction, that is, a valve hole, and a lower end portion in the drawing constitutes a valve seat of the valve portion 13. A shaft 22 is disposed in the valve hole formed by the valve seat forming member 21, and one end thereof is fixed to the pressure-sensitive piston 19.

  A valve body 23 is disposed so as to be able to open and close the valve hole, facing the valve seat by the valve seat forming member 21. The valve body 23 is formed integrally with a piston rod 24 held at one end by a shaft 22 fixed to the pressure-sensitive piston 19 and a body 15 so as to be movable back and forth in the axial direction. The outer diameter of the piston rod 24 is formed to be equal to the inner diameter of the valve hole of the valve seat forming member 21. The piston rod 24 is also urged by a spring 25 in a direction in which the valve body 23 is separated from the valve seat forming member 21. The space in which the valve body 23 is disposed is an intermediate pressure port 26 that supplies a controlled pressure Pc to the crank chamber when the variable displacement compressor control valve 11 is mounted on the variable displacement compressor. The space in which the spring 25 is disposed communicates with the low pressure port 27 that receives the suction pressure Ps of the suction chamber.

  A hole is formed in the lower center of the body 15 in the figure, and the opening edge of the bottomed sleeve 28 is tightly coupled to the hole. In the bottomed sleeve 28, a core 29 and a plunger 30 of the solenoid 14 are provided. The core 29 is fixed to the hole in the lower center of the body 15 and the bottomed sleeve 28 by press-fitting. The plunger 30 is slidably disposed in the axial direction in the bottomed sleeve 28, and is fixed to one end of a shaft 31 disposed through the core 29 in the axial direction. The plunger 30 is also urged toward the core 29 by a spring 32 so that the other end of the shaft 31 abuts on the lower end surface of the piston rod 24 in the figure. A coil 33 is disposed on the outer periphery of the bottomed sleeve 28, and a harness 34 for supplying power to the coil 33 is led out to the outside.

  In the variable displacement compressor control valve 11 having the above configuration, the spring 25 urging the piston rod 24 of the valve portion 13 toward the solenoid 14 urges the shaft 31 of the solenoid 14 toward the valve portion 13. Since the spring load is set to be larger than that of the spring 32, the valve portion 13 is held in the fully opened state because the valve body 23 is separated from the valve seat forming member 21 when the solenoid 14 is not energized. ing. In such a case, the high-pressure refrigerant having the discharge pressure Pd introduced from the discharge chamber of the variable capacity compressor to the high-pressure port 18 passes through the fully-open valve portion 13 and flows from the intermediate-pressure port 26 to the crank chamber. Become. Therefore, the variable capacity compressor is operated with the minimum discharge capacity because the crank chamber pressure Pc is close to the discharge pressure Pd.

  When the automotive air conditioner is started or when the cooling load is maximum, the control current value supplied to the solenoid 14 is maximum. At this time, since the plunger 30 is attracted to the core 29 with the maximum suction force, the piston rod 24 of the valve portion 13 is supported by the shaft 31 fixed to the plunger 30 against the urging force of the spring 25. The valve body 23 is pushed in the valve closing direction, whereby the valve body 23 is seated on the valve seat forming member 21 and the valve portion 13 is fully closed. At this time, since the high-pressure refrigerant having the discharge pressure Pd introduced into the high-pressure port 18 is blocked by the fully closed valve portion 13, the variable capacity compressor has the crank chamber pressure Pc close to the suction pressure Ps. Thus, the operation with the maximum discharge capacity is performed.

  Here, when the current value supplied to the solenoid 14 is set to a predetermined value, the valve body 23 is biased in the valve closing direction and the load of the spring 25 biased in the valve opening direction. The valve stops at a valve lift position where the load of the solenoid 14, the discharge pressure Pd received in the valve opening direction, and the suction pressure Ps received in the valve closing direction are balanced.

  In this balanced state, if the rotational speed of the variable capacity compressor is increased by increasing the engine speed and the discharge capacity is increased, the discharge pressure Pd is increased and the suction pressure Ps is decreased. (Pd−Ps) increases, and a force in the valve opening direction acts on the valve body 23 and the piston rod 24. The valve body 23 lifts the flow rate of the refrigerant flowing from the discharge chamber to the crank chamber by lifting from the balance position. Will increase. As a result, the crank chamber pressure Pc increases, the variable capacity compressor operates in a direction to decrease its discharge capacity, and the differential pressure (Pd−Ps) is controlled to be a predetermined value set by the solenoid 14. Is done. When the engine speed decreases, the reverse operation is performed, and the variable capacity compressor is controlled so that the differential pressure (Pd−Ps) becomes a predetermined value set by the solenoid 14.

  Thus, when the rotational speed of the variable capacity compressor is slowly changing, such as when the automobile is cruising at a substantially constant speed, the pressure sensing unit 12 is insensitive and the conventional variable capacity Operates in the same way as a compressor control valve. Next, the operation of the control valve 11 for the variable displacement compressor when the rotational speed of the variable capacity compressor is suddenly changed due to a sudden change in the rotational speed of the engine, such as when the automobile is suddenly accelerated or decelerated. explain.

FIG. 2 is an explanatory view of the operation of the control valve for the variable capacity compressor when the rotational speed of the variable capacity compressor has increased rapidly.
When the rotational speed of the variable capacity compressor is operating stably at, for example, 800 revolutions per minute, assuming that the variable capacity compressor suddenly rises to, for example, 2000 revolutions per minute, the variable capacity compressor control valve 11 increases the discharge pressure Pd. In response to the decrease in the suction pressure Ps, the valve lift increases, and as a result, the crank chamber pressure Pc increases. However, in a highly sensitive variable capacity compressor, as indicated by the broken line in the figure, the valve lift and discharge are increased. The pressure Pd, the crank chamber pressure Pc, and the suction pressure Ps tend to overshoot and cause a hunting phenomenon.

  At this time, the pressure-sensitive part 12 receives the rapidly increased discharge pressure Pd by the pressure-sensitive piston 19 having a sufficiently larger pressure receiving area than the valve body 23. On the other hand, since the pressure regulating chamber 20 remains at the pressure Pd (av) that is the average value of the discharge pressure Pd before increasing rapidly, the pressure-sensitive piston 19 has a differential pressure (Pd−Pd (av)). As a result, a force in a direction away from the valve portion 13 is generated. Since this force is transmitted to the valve body 23 through the shaft 22, the force obtained by subtracting the differential pressure (Pd−Pd (av)) of the pressure sensing unit 12 from the rapidly increased discharge pressure Pd is applied to the valve body 23. Will be added. As a result, as indicated by the solid line in FIG. 2, the valve lift of the variable displacement compressor control valve 11 increases more slowly, so that the pressure Pc in the crank chamber is increased more slowly. Thereafter, in the pressure-sensitive part 12, the rapidly increased discharge pressure Pd is promptly introduced into the pressure-regulating chamber 20 through the clearance between the cylinder 16 and the pressure-sensitive piston 19, so that the differential pressure (Pd−Pd (av )) Disappears, and the function of the pressure-sensitive part 12 is lost here. That is, the pressure sensing unit 12 has a function of sensing a sudden increase in the discharge pressure Pd and temporarily slowing the movement of the valve unit 13 in the valve opening direction by a value proportional to the degree of pressure change. It will be. As a result, the variable displacement compressor control valve 11 can quickly recover to a predetermined discharge capacity without hunting the variable displacement compressor.

  The above is the operation when the rotational speed of the variable capacity compressor rapidly increases, but the same applies when the rotational speed rapidly decreases. That is, when the rotational speed of the variable capacity compressor is suddenly reduced, the pressure difference (Pd (av) −Pd) of the pressure-sensitive part 12 becomes a force for moving the pressure-sensitive piston 19 toward the valve part 13. This is a force for temporarily urging the valve body 23 about to move in the valve closing direction in the valve opening direction. As a result, even when the rotational speed of the variable capacity compressor is suddenly decreased, the variable capacity compressor control valve 11 operates in the exact opposite manner as when the rotational speed of the variable capacity compressor is rapidly increased.

  In the above configuration, the pressure-sensitive piston 19 is provided with a flow rate adjusting means such as a piston ring cut to a predetermined length in the circumferential direction, and the size of the refrigerant passage that enters and exits the pressure regulating chamber 20. The characteristic of the pressure-sensitive part 12 may be adjusted by adjusting.

  FIG. 3 is a central longitudinal sectional view schematically showing a control valve for a variable capacity compressor according to a second embodiment. 3, components having the same or equivalent functions as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The variable displacement compressor control valve 11a according to the second embodiment is configured such that the variable displacement compressor control valve 11 according to the first embodiment senses a sudden change in the discharge pressure Pd and detects the valve of the valve section 13. The difference is that the lift is controlled while the valve lift of the valve portion 13 is controlled by detecting a sudden change in the pressure Pc supplied to the crank chamber.

  For this reason, in the variable displacement compressor control valve 11a according to the second embodiment, the pressure sensitive part 12 is disposed in the space communicating with the intermediate pressure port 26, and the pressure sensitive piston 19 that receives the pressure Pc is provided. It is fixed to a piston rod 24 integral with the valve body 23. The valve seat forming member 21 has a flange portion, and the flange portion is fitted into a front end opening of the body 15 in the figure. A pressure-sensitive piston 19 is loosely fitted in a position below the valve seat forming member 21 so as to advance and retreat in the axial direction, and the space of the donut-shaped pressure adjusting chamber 20 is formed by the body 15 and the flange portion of the valve seat forming member 21. Is forming. Further, the pressure-sensitive piston 19 has a concave upper central portion, and the concave portion is formed with a communication hole so as to communicate with a space communicating with the intermediate pressure port 26.

  When the variable displacement compressor control valve 11a configured as described above is controlled by a predetermined valve lift, if the discharge pressure Pd increases rapidly and the suction pressure Ps decreases rapidly, the valve body 23 and the piston rod The differential pressure (Pd−Ps) at both ends of 24 increases and the valve lift tends to increase, whereby the pressure Pc on the downstream side of the valve portion 13 also increases abruptly. At this time, since the pressure-sensitive piston 19 of the pressure-sensitive portion 12 has a sufficiently large pressure receiving area than the valve body 23, a force is generated in the pressure-sensitive piston 19 to temporarily move upward in the figure. Then, the force causes the piston rod 24 fixed to the pressure sensitive piston 19 to act in the valve closing direction. Accordingly, since the force in the valve closing direction of the pressure-sensitive piston 19 acts in the opposite direction on the valve body 23 that tends to move in the valve opening direction due to the increase in the differential pressure (Pd−Ps), the valve lift is The discharge pressure Pd and the crank chamber pressure Pc increase slowly along with this. Eventually, when the pressure in the pressure regulating chamber 20 becomes equal to the crank chamber pressure Pc, the discharge pressure Pd, the crank chamber pressure Pc, the suction pressure Ps, and the valve lift quickly return to the original without overshooting. Of course, similarly, when the rotational speed of the variable capacity compressor suddenly decreases, the variable capacity compressor control valve 11a operates slowly, and the variable capacity compressor can be quickly restored to a predetermined discharge capacity. .

  FIG. 4 is a central longitudinal sectional view schematically showing a control valve for a variable capacity compressor according to a third embodiment. 4, constituent elements having the same or equivalent functions as those shown in FIG. 1 are given the same reference numerals, and detailed descriptions thereof are omitted.

  The variable displacement compressor control valve 11b according to the third embodiment is configured such that the variable displacement compressor control valve 11 according to the first embodiment senses a sudden change in the discharge pressure Pd and detects the valve of the valve section 13. The lift is controlled, and the variable displacement compressor control valve 11a according to the second embodiment senses a sudden change in the pressure Pc supplied to the crank chamber and controls the valve lift of the valve portion 13. In contrast, the valve lift of the valve unit 13 is controlled by detecting a sudden change in the suction pressure Ps.

  For this reason, in the control valve 11b for the variable capacity compressor, the pressure sensitive piston 19 is arranged so as to block the space communicating with the low pressure port 27 and the space communicating with the solenoid 14 where the spring 25 is arranged. The piston 19 is fixed to a piston rod 24 that is integral with the valve body 23. Therefore, in the control valve 11b for the variable capacity compressor, a space surrounded by the body 15, the pressure sensitive piston 19, the piston rod 24, the core 29, and the shaft 31 forms the pressure regulating chamber 20. .

  When the control valve 11b for the variable displacement compressor having the above configuration is controlled by a predetermined valve lift, if the discharge pressure Pd increases rapidly and the suction pressure Ps decreases rapidly, the valve body 23 and the piston rod The differential pressure (Pd−Ps) at both ends of 24 increases, and the valve lift increases, whereby the suction pressure Ps decreases rapidly. At this time, since the pressure-sensitive piston 19 of the pressure-sensitive portion 12 has a pressure receiving area sufficiently larger than that of the valve body 23, the pressure-sensitive piston 19 generates a force to move upward in the figure. Causes the piston rod 24 fixed to the pressure sensitive piston 19 to act in the valve closing direction. Since a force in the valve closing direction of the pressure-sensitive piston 19 is applied to the valve body 23 in the reverse direction, the valve lift increases slowly, and the pressure increase of the discharge pressure Pd and the crank chamber pressure Pc also decreases. Eventually, when the pressure in the pressure regulating chamber 20 becomes equal to the suction pressure Ps, the discharge pressure Pd, the crank chamber pressure Pc, the suction pressure Ps, and the valve lift quickly return to the original without overshooting. Of course, similarly, when the rotational speed of the variable capacity compressor suddenly decreases, the variable capacity compressor control valve 11b operates quickly, and the variable capacity compressor can be quickly restored to a predetermined discharge capacity. it can.

  FIG. 5 is a central longitudinal sectional view schematically showing a control valve for a variable capacity compressor according to a fourth embodiment. In FIG. 5, components having the same or equivalent functions as those shown in FIG. 1 are given the same reference numerals, and detailed descriptions thereof are omitted.

  In the variable displacement compressor control valve 11c according to the fourth embodiment, in the variable displacement compressor control valve 11 according to the first embodiment, the pressure sensing unit 12 increases and decreases the discharge pressure Pd. While the valve lift of the valve unit 13 is controlled by detecting a sudden change in the direction, a sudden change in the decreasing direction of the discharge pressure Pd is detected without detecting a sudden change in the increasing direction of the discharge pressure Pd. This is different in that the valve lift of the valve unit 13 is controlled by sensitively detecting this.

  That is, in this variable displacement compressor control valve 11c, the pressure sensitive piston 19 constituting the pressure sensitive part 12 is a check for switching the sensitivity to a sudden change in the increasing direction and decreasing direction of the discharge pressure Pd. A valve mechanism (sensitivity switching means) is provided. This check valve mechanism forms a stepped passage so that the high pressure port 18 and the pressure regulating chamber 20 communicate with the pressure sensitive piston 19, and a ball-shaped valve element is formed in the passage having a large diameter on the pressure regulating chamber 20 side. 41 is arranged, and a leaf spring 42 is engaged with an opening end portion on the pressure regulating chamber 20 side so that the valve body 41 does not fall off on the pressure regulating chamber 20 side.

  When the control valve 11c for the variable displacement compressor having the above configuration is controlled by a predetermined valve lift, if the discharge pressure Pd increases rapidly, the differential pressure between the discharge pressure Pd and the pressure in the pressure regulating chamber 20 As a result, the check valve mechanism provided in the pressure-sensitive piston 19 opens immediately, and the differential pressure between the discharge pressure Pd and the pressure in the pressure regulating chamber 20 disappears. For this reason, the pressure-sensitive part 12 becomes insensitive, and the control valve 11c for the variable capacity compressor responds sensitively to the sudden increase in the discharge pressure Pd, and the valve part 13 acts in the valve opening direction rapidly. As a result, the pressure Pc in the crank chamber is increased more quickly, and the discharge capacity of the variable capacity compressor is controlled to decrease rapidly.

  On the other hand, when the discharge pressure Pd drops rapidly, the discharge pressure Pd that has dropped sharply and the pressure Pd (av) in the pressure regulating chamber 20 that is the average value of the discharge pressure Pd before the drop is suddenly reduced. Since the check valve mechanism provided in the pressure-sensitive piston 19 is closed by the differential pressure, the pressure-sensitive piston 19 having a pressure receiving area larger than that of the valve body 23 senses a change in the discharge pressure Pd that is rapidly reduced. For this reason, the valve body 23 tries to act in the valve closing direction in response to the rapid decrease in the discharge pressure Pd, but the pressure sensitive piston 19 receives the sudden pressure change and instantaneously acts in the valve opening direction. The movement of the valve body 23 in the valve closing direction is made dull. That is, the control valve 11c for the variable capacity compressor is asymmetric, such that the sensitivity is high with respect to a rapid change in the discharge pressure Pd and the sensitivity is low with respect to a rapid decrease in the discharge pressure Pd. Has valve opening characteristics. Thus, for example, even if the variable capacity compressor makes a transient response to a sudden increase in discharge pressure Pd and the discharge pressure Pd suddenly decreases, Since there is no transient response, the hunting phenomenon does not occur.

  FIG. 6 is a central longitudinal sectional view schematically showing a control valve for a variable capacity compressor according to a fifth embodiment. In FIG. 6, the same components as those shown in FIG. 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the variable displacement compressor control valve 11d according to the fifth embodiment, the variable displacement compressor control valve 11c according to the fourth embodiment has a check valve mechanism of the pressure sensing portion 12 as a pressure sensitive piston 19. The check valve mechanism is a ball valve, whereas the check valve mechanism of the pressure sensing unit 12 is provided in the lid 17 and the check valve element is a poppet valve. Is different.

  In other words, in this variable displacement compressor control valve 11 d, the check valve mechanism provided in the pressure sensing unit 12 communicates the space that receives the discharge pressure Pd with the lid 17 of the pressure sensing unit 12 and the pressure regulating chamber 20. In this way, a stepped passage is formed, and a bowl-shaped valve body 41 is disposed in a passage having a large diameter on the pressure regulating chamber 20 side, so that the valve body 41 does not fall off to the pressure regulating chamber 20 side. A leaf spring 42 is locked to the opening end on the side, and a spring 43 having a small load for urging the pressure sensitive piston 19 away from the lid 17 is arranged between the lid 17 and the pressure sensitive piston 19. Is done.

  The operation of the variable displacement compressor control valve 11d having the pressure sensing unit 12 having the above-described configuration is the same as that of the variable displacement compressor control valve 11c according to the fourth embodiment. In the fifth embodiment, the check valve mechanism is provided on the lid 17 of the pressure sensing unit 12, but the body that isolates the pressure regulating chamber 20 from the side exposed to the discharge pressure Pd. 15 may be provided.

  FIG. 7 is a central longitudinal sectional view schematically showing a control valve for a variable capacity compressor according to a sixth embodiment. In FIG. 7, the same components as those shown in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the variable displacement compressor control valve 11e according to the sixth embodiment, the variable displacement compressor control valves 11c and 11d according to the fourth and fifth embodiments have check valve mechanisms. On the other hand, there is a difference in that a sensitivity switching mechanism is provided in which the sensitivity is switched between when the discharge pressure Pd suddenly increases and when it rapidly decreases.

  That is, in the control valve 11e for the variable capacity compressor, the sensitivity switching mechanism provided in the pressure sensing unit 12 switches the ease of flow of the refrigerant entering and exiting the pressure regulating chamber 20, and the outer peripheral shape of the pressure sensitive piston 19 The taper shape has an outer diameter that gradually increases from the high-pressure port 18 side toward the pressure regulating chamber 20. Therefore, the gap on the outer periphery of the pressure-sensitive piston 19 constitutes the most narrowed throttle portion at the upper end of the pressure regulating chamber 20, and has a flow passage cross-sectional area toward the space communicating with the high-pressure port 18. It is gradually expanding. As a result, the flow passage cross-sectional area is rapidly expanding on the high pressure port 18 side of the constricted portion, and when refrigerant flows from the constricted portion to the suddenly expanded portion, a contracted flow is generated there, and the contracted flow action If the pressure difference between the high-pressure port 18 side and the pressure-regulating chamber 20 is the same, the pressure-sensing unit 12 adjusts the refrigerant that has entered the high-pressure port 18 after the refrigerant is gradually throttled. Compared to when entering the pressure chamber 20, the refrigerant flow rate is smaller when the refrigerant in the pressure adjusting chamber 20 flows to the high-pressure port 18 side after being rapidly throttled by the throttle portion.

  When the rotational speed of the variable capacity compressor increases rapidly and the discharge pressure Pd increases rapidly, the difference between the pressure of the high-pressure port 18 that has become high pressure and the pressure in the pressure regulating chamber 20 before high pressure has occurred. When the refrigerant is about to flow into the pressure regulating chamber 20 from the high-pressure port 18 side through the gap on the outer periphery of the pressure-sensitive piston 19, and conversely, when the rotational speed is suddenly reduced and the discharge pressure Pd is suddenly reduced. Then, the refrigerant tends to flow from the pressure regulating chamber 20 to the high-pressure port 18 side through the gap on the outer periphery of the pressure-sensitive piston 19. At this time, there is a difference in the flow rate of the refrigerant flowing through the gap on the outer periphery of the pressure-sensitive piston 19 between when the discharge pressure Pd suddenly increases and when the discharge pressure Pd decreases sharply, and when the discharge pressure Pd increases rapidly, When the pressure in the pressure chamber 20 is equal to the rapidly increased discharge pressure Pd and the pressure equalizing time is short, and the discharge pressure Pd is rapidly decreased, the pressure in the pressure regulating chamber 20 is rapidly increased to the discharge pressure Pd and equalized pressure. The time to become longer. The force that the pressure-sensitive piston 19 acts in the valve closing direction of the valve body 23 of the valve portion 13 when the discharge pressure Pd increases abruptly is that the pressure-sensitive piston 19 is the valve portion when the discharge pressure Pd decreases rapidly. Since the 13 valve bodies 23 are smaller than the force acting in the valve opening direction, when the discharge pressure Pd increases abruptly, the pressure-sensitive part 12 becomes insensitive and the sensitivity of the valve part 13 does not decrease much. On the other hand, in the transition period in which the discharge pressure Pd rapidly decreases, the pressure-sensitive piston 19 tends to move in the valve opening direction, so that the pressure-sensitive portion 12 becomes more sensitive. Since the differential pressure between the discharge pressure Pd and the suction pressure Ps is reduced, the force that the valve unit 13 tries to act in the valve closing direction is instantaneously canceled by the force that the pressure sensing unit 12 tries to act in the valve opening direction. Therefore, the valve body 23 of the valve portion 13 is restrained from moving in the valve closing direction. As a result, the valve section 13 does not make a transient response in the direction in which the discharge pressure Pd rapidly decreases, and therefore, a highly sensitive variable capacity compressor causes a hunting phenomenon due to a sudden pressure fluctuation of the discharge pressure Pd. There is no.

  FIG. 8 is a central longitudinal sectional view schematically showing a control valve for a variable capacity compressor according to a seventh embodiment. In FIG. 8, the same components as those shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The variable displacement compressor control valve 11f according to the seventh embodiment is the same as the variable displacement compressor control valve 11a according to the second embodiment. While the valve lift of the valve unit 13 is controlled by detecting a sudden change in the increasing direction and the decreasing direction of the valve, the rapid change in the increasing direction of the pressure Pc supplied to the crank chamber is not detected. Only the sharp change in the decreasing direction of the pressure Pc is sensitively detected to control the valve lift of the valve portion 13.

  That is, in the variable displacement compressor control valve 11f, the pressure-sensitive piston 19 constituting the pressure-sensitive portion 12 is sensitive to a sudden change in the increasing direction and decreasing direction of the pressure Pc supplied to the crank chamber. A check valve mechanism for switching is provided. This check valve mechanism forms a stepped passage so that the intermediate pressure port 26 and the pressure regulating chamber 20 are communicated with the pressure sensitive piston 19, and a ball-shaped valve is formed in the passage having a large diameter on the pressure regulating chamber 20 side. The body 41 is arranged, and a stopper 44 is fitted to the opening end on the pressure regulating chamber 20 side so that the valve body 41 does not fall into the pressure regulating chamber 20.

  When the variable displacement compressor control valve 11f configured as described above is controlled by a predetermined valve lift, the valve section 13 operates in the valve opening direction due to a sudden increase in the discharge pressure Pd to the crank chamber. When the supplied pressure Pc suddenly increases, the check valve mechanism provided in the pressure-sensitive piston 19 is immediately opened by the differential pressure between the pressure Pc in the crank chamber and the pressure in the pressure regulating chamber 20. . For this reason, since the pressure-sensitive part 12 does not affect the operation of the valve part 13, the valve part 13 quickly operates in the valve opening direction in response to the rapid increase of the pressure Pc, and the pressure Pc of the crank chamber. Is controlled more quickly, and the discharge capacity of the variable capacity compressor is quickly decreased.

  On the contrary, when the pressure Pc supplied to the crank chamber is suddenly reduced, the intermediate pressure port 26 is higher than the pressure Pc (av) in the pressure regulating chamber 20 which is an average value of the pressure Pc before the sudden reduction. Therefore, the check valve mechanism provided in the pressure-sensitive piston 19 is closed. For this reason, the pressure-sensitive piston 19 having a larger pressure receiving area than the valve body 23 sensitively senses a sudden drop in the pressure Pc, and the differential pressure between the discharge pressure Pd and the suction pressure Ps is reduced, so that the valve portion 13 is The operation in the valve closing direction is instantaneously suppressed by the pressure sensing unit 12 acting sensitively in the valve opening direction.

  As a result, the variable displacement compressor control valve 11f is highly sensitive to a sudden increase in the pressure Pc supplied to the crank chamber and sensitive to a sudden decrease in the pressure Pc. Since the asymmetric valve opening characteristic is low, hunting does not occur even if there is a sudden change in the pressure Pc due to a sudden change in the discharge pressure Pd.

  FIG. 9 is a central longitudinal sectional view schematically showing a control valve for a variable capacity compressor according to an eighth embodiment. In FIG. 9, the same components as those shown in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the variable displacement compressor control valve 11g according to the eighth embodiment, in the variable displacement compressor control valve 11b according to the third embodiment, the pressure sensing unit 12 increases and decreases the suction pressure Ps. While the valve lift of the valve unit 13 is controlled by detecting a rapid change in direction, the rapid change in the increase direction of the suction pressure Ps is detected without detecting the rapid change in the decrease direction of the suction pressure Ps. This is different in that the valve lift of the valve unit 13 is controlled by sensitively detecting this.

  That is, in this variable displacement compressor control valve 11g, a non-return for switching the sensitivity to the pressure-sensitive piston 19 constituting the pressure-sensitive portion 12 with respect to a sudden change between the increasing direction and the decreasing direction of the suction pressure Ps. A valve mechanism is provided. In this check valve mechanism, a stepped passage is formed in the pressure-sensitive piston 19 so that the low pressure port 27 and the pressure regulating chamber 20 communicate with each other, and a ball-shaped valve element 41 is formed in a large passage on the low pressure port 27 side. And a stopper 44 is fitted to the opening end on the low pressure port 27 side so that the valve body 41 does not fall into the space communicating with the low pressure port 27.

  When the variable displacement compressor control valve 11g having the above configuration is controlled by a predetermined valve lift, if the suction pressure Ps rapidly decreases due to a sudden increase in the discharge pressure Pd, the pressure sensitivity The check valve mechanism provided in the piston 19 is immediately opened by the differential pressure between the suction pressure Ps and the pressure in the pressure regulating chamber 20. For this reason, since the pressure-sensitive part 12 does not affect the operation of the valve part 13, the valve part 13 quickly operates in the valve opening direction in response to the rapid increase in the discharge pressure Pd, and the pressure in the crank chamber Pc is increased more rapidly, and the discharge capacity of the variable capacity compressor is controlled to decrease rapidly.

  On the other hand, when the suction pressure Ps increases rapidly due to the sudden decrease in the discharge pressure Pd, the pressure Ps (av) in the pressure regulating chamber 20 that is the average value of the suction pressure Ps before it increases rapidly. Since the suction pressure Ps of the low pressure port 27 becomes higher than that, the check valve mechanism provided in the pressure sensitive piston 19 is closed. For this reason, the pressure-sensitive piston 19 sensitively senses a sudden increase in the suction pressure Ps, and the valve portion 13 instantaneously suppresses the action in the valve closing direction by the pressure sensitive portion 12 acting sensitively in the valve opening direction. Is done.

  As a result, the variable displacement compressor control valve 11g is highly sensitive to a sudden change in the suction pressure Ps and low in sensitivity to a sudden increase in the pressure Pc. Since it becomes a valve characteristic, it does not hunting.

It is the center longitudinal section showing the control valve for variable capacity compressors concerning a 1st embodiment typically. It is operation | movement explanatory drawing of the control valve for variable capacity compressors when the rotation speed of a variable capacity compressor increases rapidly. It is the center longitudinal cross-sectional view which showed typically the control valve for variable capacity compressors which concerns on 2nd Embodiment. It is the center longitudinal cross-sectional view which showed typically the control valve for variable capacity compressors concerning 3rd Embodiment. It is the center longitudinal cross-sectional view which showed typically the control valve for variable capacity compressors which concerns on 4th Embodiment. It is the center longitudinal cross-sectional view which showed typically the control valve for variable capacity compressors which concerns on 5th Embodiment. It is the center longitudinal cross-sectional view which showed typically the control valve for variable capacity compressors concerning 6th Embodiment. It is the center longitudinal cross-sectional view which showed typically the control valve for variable capacity compressors concerning 7th Embodiment. It is the center longitudinal cross-sectional view which showed typically the control valve for variable capacity compressors which concerns on 8th Embodiment.

Explanation of symbols

11, 11a, 11b, 11c, 11d, 11e, 11f, 11g Control valve for variable capacity compressor 12 Pressure sensitive part 13 Valve part 14 Solenoid 15 Body 16 Cylinder 17 Lid 18 High pressure port 19 Pressure sensitive piston 20 Pressure regulating chamber 21 Valve Seat forming member 22 Shaft 23 Valve body 24 Piston rod 25 Spring 26 Medium pressure port 27 Low pressure port 28 Bottomed sleeve 29 Core 30 Plunger 31 Shaft 32 Spring 33 Coil 34 Harness 41 Valve body 42 Plate spring 43 Spring 44 Stopper Pd Discharge pressure Ps Suction pressure Pc Crank chamber pressure

Claims (13)

The refrigerant discharge capacity is changed by sensing the differential pressure between the discharge pressure of the discharge chamber of the variable capacity compressor and the suction pressure of the suction chamber and controlling the flow rate of the refrigerant flowing from the discharge chamber to the crank chamber. In the control valve for the variable displacement compressor,
A pressure-sensitive part is provided that senses a pressure change due to a sudden change in the rotational speed of the variable capacity compressor and slows the movement of the valve part in the opening / closing direction by a value proportional to the degree of the pressure change. Control valve for variable capacity compressor.   The pressure-sensitive part is provided in a high-pressure port into which the discharge pressure is introduced, receives a pressure-sensitive piston that receives the discharge pressure in a pressure-receiving area larger than a valve body, the discharge pressure received by the pressure-sensitive piston, and the 2. A shaft for transmitting axial movement generated by a differential pressure with respect to a pressure in a pressure regulating chamber closed by a pressure sensitive piston to the valve body through a valve hole. The control valve for a variable displacement compressor as described.   3. The variable displacement compression according to claim 2, wherein the shaft is integrally formed with the valve body for receiving the discharge pressure at one end face and a piston rod for receiving the suction pressure at the other end face. Control valve for machine.   The pressure-sensitive portion reduces the force that the pressure-sensitive piston acts on the valve body via the shaft when the discharge pressure is suddenly increased than when the discharge pressure is suddenly reduced. The control valve for a variable capacity compressor according to claim 2, further comprising sensitivity switching means.   The sensitivity switching means is provided in a passage formed through the pressure-sensitive piston so as to communicate the high-pressure port side and the pressure-regulating chamber, and the refrigerant switching unit moves from the high-pressure port side to the pressure-regulating chamber. 5. The control valve for a variable capacity compressor according to claim 4, wherein the control valve is a check valve that allows a flow and prevents a refrigerant flow from the pressure regulating chamber toward the high pressure port.   The sensitivity switching means is provided in a passage formed so as to communicate with the member that forms the pressure regulating chamber together with the pressure sensitive piston so that the side receiving the discharge pressure and the pressure regulating chamber communicate with each other. A check valve that prevents a refrigerant flow from the side receiving the discharge pressure to the pressure regulating chamber and allows a refrigerant flow from the pressure regulating chamber to the side receiving the discharge pressure. The control valve for a variable displacement compressor according to claim 4,   The sensitivity switching means tapers the outer periphery of the pressure-sensitive piston so that the cross-sectional area of the gap formed on the outer periphery of the pressure-sensitive piston gradually decreases from the high-pressure port side toward the pressure regulating chamber. 5. The control valve for a variable capacity compressor according to claim 4, wherein the control valve is formed in a shape.   The pressure-sensitive portion has a pressure-sensitive piston that is provided at an intermediate pressure port through which the control pressure controlled by the valve portion is led to the crank chamber and receives the control pressure with a larger pressure-receiving area than the valve body. The pressure-sensitive piston transmits the axial movement generated by the differential pressure between the control pressure received by the pressure-sensitive piston and the pressure in the pressure regulating chamber closed by the pressure-sensitive piston to the valve body. The control valve for a variable capacity compressor according to claim 1.   The pressure-sensing unit is configured to change sensitivity so that the force acting on the valve element by the pressure-sensitive piston is smaller when the control pressure is suddenly increased than when the control pressure is suddenly reduced. 9. The control valve for a variable capacity compressor according to claim 8, further comprising means.   The sensitivity switching means is provided in a passage formed through the pressure-sensitive piston so as to communicate the intermediate pressure port side and the pressure regulating chamber, and is directed from the intermediate pressure port side to the pressure regulating chamber. The control valve for a variable capacity compressor according to claim 9, wherein the control valve is a check valve that allows a refrigerant flow and prevents a refrigerant flow from the pressure regulating chamber toward the intermediate pressure port.   The pressure-sensitive portion has a pressure-sensitive piston that is provided in a low-pressure port into which the suction pressure is introduced and receives the suction pressure in a pressure-receiving area larger than that of the valve body, and the pressure-sensitive piston receives the pressure. 2. The variable capacity according to claim 1, wherein an axial movement generated by a differential pressure between the suction pressure and a pressure in a pressure regulating chamber closed by the pressure-sensitive piston is transmitted to the valve body. Control valve for compressor.   The pressure-sensing unit is configured to change sensitivity so that the force acting on the valve body by the pressure-sensitive piston is larger when the suction pressure is suddenly increased than when the suction pressure is suddenly reduced. The control valve for a variable capacity compressor according to claim 11, further comprising means. The sensitivity switching means is provided in a passage formed through the pressure-sensitive piston so as to communicate the low-pressure port side and the pressure-regulating chamber, and the refrigerant switching unit moves from the low-pressure port side to the pressure-regulating chamber. 13. The control valve for a variable capacity compressor according to claim 12, wherein the control valve is a check valve that allows a flow and prevents a refrigerant flow from the pressure regulating chamber toward the low pressure port.

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