JP4550651B2 - Control valve for variable displacement compressor - Google Patents

Description

  The present invention relates to a control valve for a variable displacement compressor used in a car air conditioner and the like, and in particular, a variable displacement compressor capable of improving responsiveness effectively and improving control accuracy. The present invention relates to a control valve.

  In general, a control valve for a variable displacement compressor used in a car air conditioner or the like introduces a refrigerant having a discharge pressure Pd from a compressor (discharge chamber) in order to adjust a pressure Pc in a crank chamber of the compressor. The refrigerant having the discharge pressure Pd is squeezed out and led to the crank chamber, and the derivation amount (throttle amount) to the crank chamber is controlled according to the suction pressure Ps of the compressor. As seen in Patent Document 1 and the like, various proposals or practical applications using electromagnetic actuators (solenoids) have been made.

  A conventional example of such a variable displacement compressor control valve is shown in FIG. The illustrated control valve 5 includes a valve rod 15 ′ having a valve body portion 15 a and a valve chamber 21 provided with a valve seat (valve port) 22 to which the valve body portion 15 a comes in contact with and away from the valve body 15 a. A plurality of discharge pressure refrigerant inlets 25 with a filter 25A for introducing a refrigerant having a discharge pressure Pd from the compressor are provided on the outer peripheral portion (upstream side of the valve seat 22), and below (downstream side) of the valve seat 22 A valve body 20 ′ provided with a refrigerant outlet 26 communicating with the crank chamber of the compressor, and an electromagnetic actuator 30 are provided.

  The electromagnetic actuator 30 includes a coil 32 having a connector portion 31 for energization excitation, a cylindrical stator 33 disposed on the inner peripheral side of the coil 32, and a concave section that is press-fitted and fixed to the inner periphery of the lower end portion of the stator 33. Pipe-shaped suction element 34, pipe 35 with flange 35a whose upper end is joined to the outer periphery (step part) of the lower end of stator 33 by TIG welding, and the upper and lower sides of pipe 35 below the suction element 34 A plunger 37 slidably disposed in the direction and a cylindrical housing 60 with a bottomed hole disposed so as to cover the outer periphery of the coil 32 are provided.

  Further, an adjusting screw 65 having a hexagonal hole is screwed onto the stator 33, and a suction pressure Ps of the compressor is interposed between the adjusting screw 65 and the suction element 34 on the inner peripheral side of the stator 33. Is formed in the pressure sensing chamber 45. The pressure sensing chamber 45 includes a bellows 41, a reverse convex upper stopper 42, a reverse concave lower stopper 43, and a compression coil. A bellows body 40 comprising a spring 44 is disposed, and further, a compression coil that urges the bellows body 40 and the suction element 34 in a direction in which the bellows body 40 contracts (a direction in which the bellows body 40 is compressed toward the adjustment screw 65). A spring 46 is disposed. Also, a stepped operating rod 14 that passes through the suction element 34 is disposed between the lower stopper 43 (reverse concave part thereof) of the bellows body 40 and the plunger 37 (recessed part 37c thereof). A valve-opening spring 47 made up of a compression coil spring that biases the valve rod 15 ′ downward (in the valve-opening direction) via the plunger 37 is disposed between the pipe 34 and the plunger 37 (the concave portion 37 b). .

  On the other hand, a convex stopper portion 28 for restricting the lowest position of the plunger 37 protrudes from the upper center of the valve body 20, and the central portion above the valve chamber including the convex stopper portion 28 includes: A guide hole 19 into which the valve stem 15 ′ is slidably fitted is formed. In addition, a suction pressure refrigerant introduction chamber 23 into which a refrigerant having a suction pressure of the compressor is introduced is formed between the plunger 37 and the upper outer periphery (outer periphery of the convex stopper portion 28) of the valve body 20 ′. A plurality of suction pressure refrigerant introduction ports 27 are formed on the outer peripheral side, and the refrigerant having the suction pressure Ps introduced from the suction pressure refrigerant introduction port 27 into the suction pressure refrigerant introduction chamber 23 is formed on the outer periphery of the plunger 37. Are introduced into the pressure-sensitive chamber 45 through the longitudinal grooves 37a, 37a,..., The communication hole 37d formed in the central portion, the communication hole 39 formed in the suction element 34, and the like.

  A valve closing spring 48 made of a conical compression coil spring that biases the valve rod 15 ′ upward is disposed at the lower part (refrigerant outlet 26) of the valve body 20. Due to the urging force, the upper end portion of the valve stem 15 ′ is always in pressure contact with the plunger 37 (the communication hole 37d portion thereof).

  Further, a lower end flange 35a of the pipe 35 is placed on the upper end of the valve body 20 ′ via an O-ring 57, and a flange 56a is provided between the flange 35a and the coil 32. A short cylindrical pipe holder 56 is interposed, and the flange portions 35a and 56a are fastened and fixed together by an upper end outer periphery caulking portion 29 of the valve body 20 ′. Further, the bottom portion 61 with a hole of the housing 60 is press-fitted and fixed to the upper end portion of the pipe holder 56, and the upper end portion 62 of the housing 60 is caulked and fixed on the flange-shaped portion 31 c of the connector portion 31. An O-ring 66 is interposed between the connector part 31 and the coil 32. A concave portion 31a is formed at the lower center of the connector portion 31. The concave portion 31a is formed with a convex portion 31b fitted into the hexagonal hole of the adjusting screw 65. The stator 33 and the adjusting screw are formed in the concave portion 31a. The upper part of 65 is inserted.

  In the control valve 5 having such a configuration, when the solenoid portion including the coil 32, the stator 33, and the attractor 34 is energized and energized, the plunger 37 is attracted to the attractor 34. 'Is moved upward (in the valve closing direction) by the urging force of the valve closing spring 48. On the other hand, the refrigerant having the suction pressure Ps introduced from the compressor to the suction pressure introduction port 27 communicates with the longitudinal grooves 37a, 37a,... Formed in the outer periphery of the plunger 37 from the introduction chamber 23 and the suction element 39. The bellows body 40 (inside the vacuum pressure) is expanded and contracted according to the pressure in the pressure sensitive chamber 45 (suction pressure Ps), and contracts and decreases when the suction pressure Ps is high. The displacement is transmitted to the valve stem 15 ′ via the actuating rod 14 and the plunger 37, whereby the valve opening degree (effective passage cross-sectional area between the valve seat 22 and the valve body portion 15a) is increased. Adjusted. That is, the opening degree of the valve includes the attraction force of the plunger 37 by the solenoid portion including the coil 32, the stator 33 and the attraction element 34, the urging force of the bellows body 40, According to the valve opening, the amount of discharge pressure Pd introduced from the discharge pressure refrigerant introduction port 25 into the valve chamber 21 to the refrigerant outlet 26 side, that is, the amount (throttle amount) to the crank chamber is adjusted. Thus, the pressure (supply pressure) Pc in the crank chamber is controlled.

JP-A-2002-303262

  In the control valve 5 for the variable displacement compressor as described above, the responsiveness of the pressure control is improved, that is, when the valve is opened, the pressure (supply pressure) Pc in the crank chamber is quickly brought close (increased) to the discharge pressure Pd. When the valve is closed, the suction pressure Ps needs to be brought close to (increased) the supply pressure Pc quickly. In this case, in order to suppress an increase in cost, a measure for improving the responsiveness while sharing parts with other control valves such as the control valve 5 is desired. In order to quickly increase the supply pressure Pc when the valve body portion 15a opens the valve port 22, the flow rate of the refrigerant supplied from the refrigerant outlet 26 to the compressor crank chamber can be increased by increasing the valve port 22. . However, an effective measure for quickly bringing the suction pressure Ps close to the supply pressure Pc when the valve body portion 15a closes the valve port 22 has not been proposed yet.

  Further, when the valve port 22 is enlarged to increase the flow rate of the refrigerant supplied from the refrigerant outlet 26 to the compressor crank chamber in order to improve the responsiveness when the valve is opened, the following problems may occur. . That is, when the refrigerant flow rate is increased as described above, the pressure on the refrigerant outlet 26 side (supply pressure Pc to the crank chamber) acting on the valve rod 15 '(valve body portion 15a) increases. In the conventional control valve 5, the influence due to the differential pressure (Pc−Ps) between the supply pressure Pc and the suction pressure Ps (acting on the upper end surface of the valve rod 15 ′) when the valve is opened is slight. Although the above is negligible, if the flow rate of the refrigerant is increased by increasing the valve port 22 in order to improve the responsiveness, the influence of the differential pressure between the supply pressure Pc and the suction pressure Ps increases, and electromagnetic When the specifications of the type actuator 30 and the pressure-sensitive response member 40 are the same (shared), the valve rod 15 ′ (valve body portion 15a) is pushed upward (closed direction) by this differential pressure, It adversely affects control (decrease in control accuracy, etc.).

  In the control valve 5 as described above, the pressure of the refrigerant introduced into the valve chamber 21 from the discharge pressure refrigerant inlet 25 (discharge pressure Pd) is the pressure of the refrigerant in the suction pressure refrigerant introduction chamber 23 (intake pressure). Ps), a part of the refrigerant introduced into the valve chamber 21 when the valve is closed leaks into the suction pressure refrigerant introduction chamber 23 through the space between the sliding surface of the valve rod 15 'and the guide hole 19, but this Pd → As the amount of Ps leakage increases, the control is adversely affected. Therefore, it is desirable to reduce the amount of Pd → Ps leakage as much as possible.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a variable capacitor that can effectively improve responsiveness and improve control accuracy while suppressing an increase in cost. It is to provide a control valve for a type compressor.

In order to achieve the above object, a control valve for a variable displacement compressor according to the present invention basically includes a valve stem having a valve body and a guide hole into which the valve stem is slidably inserted. And a valve chamber provided with a valve port for contacting and separating the valve body, and provided with a discharge pressure refrigerant inlet for introducing a refrigerant of discharge pressure from the compressor upstream from the valve port, A valve main body provided with a refrigerant outlet communicating with the crank chamber of the compressor downstream from the valve port, a coil, a cylindrical stator disposed on the inner peripheral side of the coil, and fixed to the stator An electromagnetic actuator having an attractor and a plunger slidably disposed in the vertical direction below the attractor; and formed above the attractor on the inner peripheral side of the stator and from the compressor Pressure-sensitive chamber into which suction pressure is introduced, and a pressure-sensitive response portion disposed in the pressure-sensitive chamber When provided with a photosensitive圧応moving member, an actuating rod which Zaisa distribution between the plunger.

Then, before between the valve body and Kipu plunger, wherein with the suction pressure refrigerant introduction chamber refrigerant is introduced in the suction pressure is formed, so as to running through the valve stem, the refrigerant pressure at the refrigerant outlet A through hole is formed to guide the suction pressure refrigerant into the suction pressure refrigerant introduction chamber, and the upper end opening of the through hole can be opened and closed by moving the plunger up and down.

  In a preferred embodiment, a small-diameter hole portion is provided at the upper portion of the guide hole, and a small-diameter portion that is slidably fitted into the small-diameter hole portion is provided at the upper portion of the valve rod, and the refrigerant outlet is provided in the valve rod. The pressure equalizing pressure formed between the through-hole and the large-diameter hole portion below the small-diameter hole portion in the guide hole and the large-diameter portion below the small-diameter portion in the valve rod. A pressure equalizing communication hole leading to the introduction chamber is formed.

  Moreover, in another preferable aspect, a ring-shaped groove is formed on the outer periphery of a portion of the valve stem that is in sliding contact with the large-diameter hole portion of the guide hole.

  In the control valve for a variable displacement compressor according to the present invention, for example, when the plunger of the electromagnetic actuator is attracted to the attractor, the valve rod (valve body portion) is moved upward along with the plunger by the urging force of the valve closing spring. (The closing direction), the valve body part contacts the valve port and closes it, and in this state the upward movement of the valve stem is stopped, but from this valve closed state the plunger (valve part) Furthermore, it is attracted to a suction element, and the valve body part provided in the plunger leaves | separates from the upper end (upper end opening of a through-hole) of a valve stem. As a result, the upper end opening of the through hole is opened, the pressure on the refrigerant outlet side (supply pressure Pc to the crank chamber) is introduced into the suction pressure refrigerant introduction chamber through the through hole, and the suction pressure Ps is quickly supplied to the supply pressure Pc. To be close to. As a result, the responsiveness when the valve is closed is improved.

  In addition, the improvement of the responsiveness when the valve is opened is achieved by increasing the flow rate of the refrigerant supplied from the refrigerant outlet to the compressor crank chamber by increasing the valve opening.

  On the other hand, when the valve is opened, the pressure on the refrigerant outlet side (supply pressure Pc to the crank chamber) acting on the valve body of the valve rod is equalized through the through hole and the pressure equalizing communication hole formed in the valve rod. It is led to the pressure introduction chamber for pressure and acts on the large diameter part (shoulder part = terrace part) of the valve stem. That is, the supply pressure Pc introduced to the pressure equalization pressure introduction chamber acts in a direction to push down the valve rod, that is, in a direction to reduce (cancel) the differential pressure between the supply pressure Pc and the suction pressure Ps. For this reason, even if the valve port is enlarged to increase the responsiveness and the refrigerant flow rate is increased, the valve stem (valve part) is moved upward (closed direction) by the differential pressure between the supply pressure Pc and the suction pressure Ps. Therefore, the control problem is solved and the control accuracy is improved.

  Further, a part of the refrigerant introduced into the valve chamber from the discharge pressure refrigerant inlet is led to the pressure equalizing pressure introducing chamber through the sliding surface between the valve rod and the guide hole, and from here the pressure equalizing communication hole and It is led out to the refrigerant outlet through the through hole. In other words, there is almost no leakage from the discharge pressure Pd to the suction pressure Ps in the conventional control valve, and the discharge pressure Pd goes to the supply pressure Pc side, so that the control is not adversely affected. Improvement and the like.

Hereinafter, embodiments of a control valve for a variable displacement compressor of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a control valve for a variable displacement compressor according to the present invention.

  A variable displacement compressor control valve 1 shown in FIG. 1 includes an electromagnetic actuator 30 and a pressure-sensitive responsive member (bellows main body) 40 in the conventional variable displacement compressor control valve 5 shown in FIG. In the following, the parts corresponding to the respective parts of the control valve 5 for the variable capacity compressor shown in FIG. 3 will be described. The same reference numerals are attached, and the differences will be described mainly.

  The illustrated control valve 1 has a larger diameter than that of the control valve 5, in which a valve body 15 having a cross-shaped or T-shaped valve body 15 a (detailed later) and a valve body 15 a are in contact with and separated from each other. The valve chamber 21 is provided with a valve opening (valve seat) 22, and a plurality of refrigerants for introducing a refrigerant having a discharge pressure Pd from the compressor to the outer peripheral portion (upstream side of the valve seat 22) of the valve chamber 21. A discharge pressure refrigerant introduction port 25 is provided, and a valve main body 20 provided with a refrigerant outlet 26 communicating with a crank chamber of the compressor below the valve seat 22 (downstream side), and an electromagnetic actuator 30 are provided.

  The electromagnetic actuator 30 includes an electromagnetic coil 32 having a connector portion 31 for energization excitation, a stepped cylindrical stator 33 disposed on the inner peripheral side of the coil 32, and press-fitted and fixed to the inner periphery of the lower end of the stator 33. A suction member 34 having a concave cross section, a plunger 37 disposed below the suction member 34 so as to be slidable in the vertical direction on the inner peripheral side of the guide pipe 35, and an inner periphery of the upper end portion of the lower end portion of the stator 33. A cylindrical guide pipe 35 for guiding the plunger 37, which is connected and fixed by brazing, a stepped cylindrical housing 60 disposed so as to cover the outer periphery of the coil 32, and an upper end portion of the valve body 20 And a short cylindrical holder 50 disposed between the coil 32 and the coil 32.

  The lower end portion of the pipe 35 is fitted into the inner periphery of the holder 50 and connected and fixed by brazing, and the lower small diameter portion 61 of the housing 60 is press-fitted into the outer periphery of the holder 50. An upper end portion 62 of the housing 60 is caulked and fixed near the upper end portion of the coil 32. At the lower part of the holder 50, there is provided a cylindrical portion 50a with a thin flange that is fitted on the outer periphery of the upper portion of the valve body 20, and the holder 50 is fixed to the valve body 20 by peeling and staking the cylindrical portion 50a with the thin flange. Has been.

  Further, an adjusting screw 65 having a hexagonal hole is screwed onto the stator 33, and a suction pressure Ps of the compressor is interposed between the adjusting screw 65 and the suction element 34 on the inner peripheral side of the stator 33. Is formed in the pressure sensing chamber 45. The pressure sensing chamber 45 includes a bellows 41, a reverse convex upper stopper 42, a reverse concave lower stopper 43, and a compression coil. A bellows body 40 comprising a spring 44 is disposed, and further, a compression coil that urges the bellows body 40 and the suction element 34 in a direction in which the bellows body 40 contracts (a direction in which the bellows body 40 is compressed toward the adjustment screw 65). A spring 46 is disposed. Also, a stepped operating rod 14 that passes through the suction element 34 is disposed between the lower stopper 43 (reverse concave part thereof) of the bellows body 40 and the plunger 37 (recessed part 37c thereof). A valve-opening spring 47 made of a compression coil spring that biases the valve rod 15 downward (in the valve-opening direction) via the plunger 37 is disposed between the valve 34 and the plunger 37 (the recess 37b).

  On the other hand, a convex stopper portion 28 for restricting the lowest position of the plunger 37 protrudes from the upper center of the valve body 20, and the central portion above the valve chamber including the convex stopper portion 28 includes: A guide hole 19 (described in detail later) into which the valve stem 15 is slidably fitted is formed. In addition, a suction pressure refrigerant introduction chamber 23 into which a refrigerant having a suction pressure Ps of the compressor is introduced is formed between the plunger 37 and the upper outer periphery (outer periphery of the convex stopper portion 28) of the valve body 20. A plurality of suction pressure refrigerant inlets 27 are formed on the outer peripheral side, and the suction pressure Ps introduced into the introduction chamber 23 from the inlet 27 is a longitudinal groove 37a, 37a,... In addition to being introduced into the pressure sensitive chamber 45 through a communication hole 39 formed in the child 34, it also acts on the upper end surface of the valve rod 15. Here, the hole 37d drilled in the central portion of the plunger 37 is provided to be used for mounting a ball valve body 37A described later, and has a function different from that of the communication hole 37d of the control valve 5 of the conventional example. To do.

  Further, in the refrigerant outlet 26 provided at the lowermost part of the valve body 20, the valve rod 15 is urged upward so that its upper end portion (upper end opening portion of a through hole 51 described later) A valve closing spring 48 comprising a conical compression coil spring that is pressed against the ball valve body 37A) is arranged.

  And in the control valve 1 of this embodiment, in order to improve responsiveness, the diameter of the said valve port 22, the valve rod 15, and the guide hole 10 is larger than the diameter of the control valve 5 shown by FIG. 3 mentioned above. As shown in FIG. 2 (partially enlarged view) in addition to FIG. 1, a small-diameter hole portion 19 b is provided in the upper portion of the guide hole 19 and the upper portion of the valve stem 15. The small-diameter portion 15b is slidably fitted into the small-diameter hole portion 19b, and the refrigerant pressure Pc at the refrigerant outlet 26 is set to the suction pressure refrigerant introduction chamber 23 so as to pass through the central portion of the valve rod 15. A ball valve body 37A is fixed by caulking at the center of the lower end of the plunger 37 so as to open and close the upper end opening of the through hole 51.

  Further, near the upper end of the large-diameter portion 15A of the valve stem 15, the refrigerant pressure Pc at the refrigerant outlet 26 from the through-hole 51 is larger than the small-diameter hole portion 19b of the guide hole 19 below the large-diameter hole portion. A plurality of pressure equalizing communication holes (lateral holes) 51a leading to a pressure equalizing pressure introduction chamber 52 formed between 19A and the large diameter portion 15A below the small diameter portion 15b of the valve stem 15 are formed. Yes. In addition, three ring-shaped grooves 15c are formed on the outer periphery of a portion (near the lower end) of the large diameter portion 15A of the valve stem 15 that is in sliding contact with the guide hole 19.

  In the control valve 1 configured as described above, when the solenoid portion including the coil 32, the stator 33, and the attractor 34 is energized and energized, the plunger 37 is attracted to the attractor 34. Is moved upward (in the valve closing direction) by the urging force of the valve closing spring 48. On the other hand, the refrigerant having the suction pressure Ps introduced from the compressor to the suction pressure introduction port 27 communicates with the longitudinal grooves 37a, 37a,... Formed in the outer periphery of the plunger 37 from the introduction chamber 23 and the suction element 39. The bellows body 40 (inside the vacuum pressure) is expanded and contracted according to the pressure in the pressure sensitive chamber 45 (suction pressure Ps), and contracts and decreases when the suction pressure Ps is high. The displacement is transmitted to the valve stem 15 via the actuating rod 14 and the plunger 37, thereby adjusting the valve opening (effective passage cross-sectional area between the valve port 22 and the valve body 15a). Is done. That is, the opening degree of the valve includes the attraction force of the plunger 37 by the solenoid portion including the coil 32, the stator 33 and the attraction element 34, the urging force of the bellows body 40, the urging force by the valve opening spring 47 and the valve closing spring 48, In accordance with the valve opening, the amount of discharge pressure Pd introduced from the discharge pressure refrigerant introduction port 25 into the valve chamber 21 to the refrigerant outlet 26 side, that is, the crank chamber is adjusted (throttle amount). As a result, the pressure (supply pressure) Pc in the crank chamber is controlled.

  In the variable displacement compressor control valve 1 of the present embodiment, when the plunger 37 of the electromagnetic actuator 30 is attracted to the attractor 4, the valve rod 15 (valve body portion 15 a) is biased by the valve closing spring 48. As a result, the valve body 15a contacts the valve port 22 and closes it, and in this state, the upward movement of the valve stem 15 is stopped. From the state, the plunger 37 (the ball valve body 37A) is further attracted to the suction element, and the ball valve body 37A is separated from the upper end of the valve rod 15 (the upper end opening of the through hole 51). As a result, the upper end opening of the through hole 51 is opened, and the pressure on the refrigerant outlet side (supply pressure Pc to the crank chamber) is introduced into the suction pressure refrigerant introduction chamber 23 through the through hole 51, and the suction pressure Ps is quickly increased. The pressure is brought close to the supply pressure Pc. As a result, the responsiveness when the valve is closed is improved.

  Further, since the valve port 22 and the like are enlarged, the flow rate of the refrigerant supplied from the refrigerant outlet 26 to the compressor crank chamber is increased, so that the responsiveness when the valve is opened is also improved.

  On the other hand, when the valve is open, the pressure on the refrigerant outlet side (supply pressure Pc to the crank chamber) acting on the valve body 15a of the valve rod 15 is the through hole 51 formed in the valve rod 15 and the pressure equalizing communication hole. The pressure is introduced into the pressure equalizing pressure introduction chamber 52 through 51a and acts on the large diameter portion 15A (shoulder portion = terrace portion) of the valve rod 15. That is, the supply pressure Pc guided to the pressure equalization pressure introduction chamber 52 is in a direction in which the valve rod 15 is pushed down, that is, in a direction in which the influence of the differential pressure between the supply pressure Pc and the suction pressure Ps is reduced (cancelled). work. For this reason, even if the valve port 22 is enlarged to increase the responsiveness and the refrigerant flow rate is increased, the valve stem (valve part) is moved upward (closed direction) by the differential pressure between the supply pressure Pc and the suction pressure Ps. ), The control problem is solved, and the control accuracy is improved.

  Further, a part of the refrigerant introduced into the valve chamber from the discharge pressure refrigerant inlet 25 passes through between the sliding contact surfaces of the valve rod 15 and the guide hole 19 and is guided to the pressure equalizing pressure introducing chamber 52, from which the leveling is introduced. It is led out to the refrigerant outlet 26 through the pressure communication hole 51 a and the through hole 51. In other words, leakage from the discharge pressure Pd to the suction pressure Ps in the conventional control valve 5 hardly occurs, and the discharge pressure Pd is released to the supply pressure Pc side, so that the control is not adversely affected. The accuracy is improved.

  Further, since the ring-shaped groove 15c is formed in the valve rod 15, the labyrinth effect by the ring-shaped groove 15c reduces leakage from the discharge pressure Pd to the supply pressure Pc, and the ring-shaped groove 15c Since the minute foreign matter entering between the sliding contact surfaces of the valve stem 15 and the guide hole 19 is captured, the minute foreign matter is less likely to be clogged between the sliding contact surfaces of the valve stem 15 and the guide hole 19, and the valve stem 15 is malfunctioning. For example, even if the plunger 37 is attracted to the suction element 34, it is possible to obtain an effect that it is difficult to cause a situation in which the valve stem 15 is left without being moved upward.

The longitudinal section showing one embodiment of the control valve for variable capacity type compressors concerning the present invention. FIG. 2 is an enlarged longitudinal sectional view of a main part of the control valve shown in FIG. 1. The longitudinal cross-sectional view which shows an example of the conventional control valve for variable displacement compressors.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control valve 14 for variable capacity type compressors Actuating rod 15 Valve rod 15A Large diameter portion 15a Valve body portion 15b Small diameter portion 15c Ring-shaped groove 19 Guide hole 19A Large diameter hole portion 19b Small diameter hole portion 20 Valve body 21 Valve chamber 22 Valve Port 23 Suction pressure refrigerant introduction chamber 25 Discharge pressure refrigerant introduction port 26 Refrigerant outlet 27 Suction pressure refrigerant introduction port 30 Electromagnetic actuator 32 Coil 33 Stator 34 Suction element 35 Pipe 37 Plunger 40 Bellows body 45 Pressure sensing chamber 47 Valve opening spring 48 Closed Valve spring 51 Through hole 51a Pressure equalizing communication hole 52 Pressure equalizing pressure introduction chamber

Claims (3)

  A valve stem having a valve body portion, a guide hole into which the valve stem is slidably inserted, and a valve chamber provided with a valve port for contacting and separating the valve body portion, and upstream of the valve port A valve body provided with a discharge pressure refrigerant inlet for introducing refrigerant at a discharge pressure from the compressor on the side, and provided with a refrigerant outlet communicating with the crank chamber of the compressor on the downstream side of the valve port, and a coil An electromagnetic type having a cylindrical stator disposed on the inner peripheral side of the coil, an attractor fixed to the stator, and a plunger disposed slidably in the vertical direction below the attractor An actuator, a pressure-sensitive chamber formed above the suction element on the inner peripheral side of the stator and into which suction pressure is introduced from the compressor, a pressure-sensitive response member disposed in the pressure-sensitive chamber, An operating rod disposed between the pressure-sensitive response member and the plunger, and A suction pressure refrigerant introduction chamber into which the refrigerant having the suction pressure is introduced is formed between the ranger and the valve body, and the refrigerant pressure at the refrigerant outlet is set to the suction pressure refrigerant so as to pass through the valve rod. A control valve for a variable displacement compressor, wherein a through-hole leading to an introduction chamber is formed, and an upper end opening of the through-hole can be opened and closed by moving the plunger up and down. A small-diameter hole is provided in the upper portion of the guide hole, and a small-diameter portion that is slidably fitted into the small-diameter hole is provided in the upper portion of the valve stem. The valve rod is supplied with a refrigerant pressure at the refrigerant outlet. The through hole leads to a pressure equalizing pressure introducing chamber formed between a large diameter hole portion below the small diameter hole portion in the guide hole and a large diameter portion below the small diameter portion in the valve rod. 2. The control valve for a variable displacement compressor according to claim 1 , wherein a pressure equalizing communication hole is formed. The control valve for a variable capacity compressor according to claim 1 or 2, characterized in that the outer peripheral ring-shaped groove of the sliding contact portion in the large diameter hole portion of the guide hole in the valve stem is formed.

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