JP6500185B2 - Control valve for variable displacement compressor - Google Patents

Description

  The present invention relates to a control valve that controls the displacement of a variable displacement compressor.

  In general, a vehicle air conditioner is configured by arranging a compressor, a condenser, an expansion device, an evaporator, and the like in a refrigeration cycle. As the compressor, a variable displacement compressor (also referred to simply as a “compressor”) capable of varying the discharge capacity of the refrigerant is used so that a constant cooling capacity is maintained regardless of the number of revolutions of the engine. In this compressor, a compression piston is connected to a rocking plate attached to a rotating shaft driven by an engine, and the discharge amount of refrigerant is adjusted by changing the stroke of the piston by changing the angle of the rocking plate Do. The angle of the rocking plate can be changed continuously by introducing a portion of the discharged refrigerant into the sealed control chamber and changing the balance of the pressure on both sides of the piston. The pressure in the control chamber (hereinafter referred to as "control pressure") Pc is controlled by, for example, a control valve provided between the discharge chamber of the compressor and the control chamber.

  By the way, as such a control valve, a main valve is provided in the main passage for communicating the discharge chamber with the control chamber, while a sub valve is provided in the auxiliary passage for communicating the control chamber with the suction chamber, There is one which is driven by a solenoid (see, for example, Patent Document 1). According to this control valve, the opening degree of the main valve is adjusted in a state in which the sub valve is closed during steady operation of the air conditioner. Thus, as described above, the control pressure Pc can be adjusted to control the displacement of the compressor. On the other hand, at the time of startup of the air conditioner, the auxiliary valve is opened with the main valve closed, whereby the control pressure Pc is reduced promptly to cause the compressor to transition to the maximum capacity operating state relatively quickly. Can be demonstrated.

Unexamined-Japanese-Patent No. 2014-95463

  However, in such a control valve, generally, a PWM (Pulse Width Modulation) method is adopted for controlling energization of a solenoid. For this reason, as described later, the main valve body strokes while slightly vibrating in accordance with the frequency of the PWM control. Therefore, when the main valve is in the slightly open state, the main valve body may hit the main valve seat by its amplitude and may bounce back by its reaction. If the opening degree of the main valve is increased due to the return of the main valve body, there is a possibility that an unintended suction pressure may be increased in the compressor.

  The present invention has been made in view of such problems, and an object thereof is to suppress an unintended increase in suction pressure when a control valve of a PWM control system is installed in a variable displacement compressor.

  One aspect of the present invention compresses the refrigerant introduced into the suction chamber and discharges the discharge capacity of the variable displacement compressor from the discharge chamber from the discharge chamber to the flow rate of the refrigerant or from the control chamber to the suction chamber It is a control valve which changes by adjusting the flow rate of the refrigerant | coolant derived | led-out. The control valve includes a body having a main passage communicating the discharge chamber with the control chamber, a sub passage formed between the control chamber and the suction chamber, a main valve seat provided in the main passage, and a main valve. The main valve body that opens and closes the main valve by attaching and detaching to the seat, the auxiliary valve seat provided to the auxiliary passage, the auxiliary valve body that opens and closes the auxiliary valve by attaching to the auxiliary valve seat, and the closing direction of the main valve A solenoid for generating a driving force, an operating rod for transmitting the driving force of the solenoid to the main valve body and the auxiliary valve body, and a first biasing member for applying an urging force in the valve opening direction to the main valve And a second biasing member for applying a biasing force in the valve closing direction to the sub valve. The solenoid is subjected to energization control by the PWM method. Before the main valve completely closes, there is a state in which the main valve and the auxiliary valve open simultaneously.

  According to this aspect, the auxiliary valve can be easily opened in the fully open state of the main valve. For this reason, even if it is intended to increase the degree of opening of the main valve by springbacking of the main valve, the pressure in the control chamber and hence the pressure in the suction chamber can be suppressed by opening the sub valve. Such stabilization of the pressure in the control chamber consequently absorbs the vibration of the main valve body and suppresses its rebound. As a result, an unintended increase in suction pressure in the compressor can be suppressed.

  According to the present invention, when the control valve of the PWM control system is installed in the variable displacement compressor, it is possible to suppress an unintended increase in suction pressure.

It is a sectional view showing the composition of the control valve concerning a 1st embodiment. It is a partial expanded sectional view corresponding to the upper half part of FIG. It is a figure showing operation of a control valve. It is a figure showing operation of a control valve. It is a figure showing operation of a control valve. It is a figure showing the valve-opening characteristic of a control valve. It is a figure showing the valve-opening characteristic of the control valve concerning a 2nd embodiment. It is a figure showing the valve-opening characteristic of the control valve concerning a 3rd embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, for convenience, the positional relationship of each structure may be expressed as upper and lower based on the illustrated state.

First Embodiment
FIG. 1 is a cross-sectional view showing the configuration of the control valve according to the first embodiment.
The control valve 1 is configured as a solenoid valve that controls the discharge capacity of a variable displacement compressor (not shown) (referred to simply as a “compressor”) as a target device installed in a refrigeration cycle of an automotive air conditioner. The compressor compresses the refrigerant flowing in the refrigeration cycle to discharge it as a high-temperature, high-pressure gas refrigerant. The gas refrigerant is condensed in a condenser (external heat exchanger) and adiabatically expanded by an expansion device to become a low-temperature low-pressure mist refrigerant. The low-temperature low-pressure refrigerant evaporates in the evaporator, and the evaporation latent heat cools the passenger compartment air. The refrigerant evaporated by the evaporator is returned to the compressor again to circulate in the refrigeration cycle. The compressor has a rotating shaft rotationally driven by the engine of the automobile, and a piston for compression is connected to a rocking plate attached to the rotating shaft. By changing the angle of the rocking plate to change the stroke of the piston, the discharge amount of the refrigerant is adjusted. The control valve 1 controls the flow rate of the refrigerant introduced from the discharge chamber of the compressor to the control chamber, thereby changing the angle of the rocking plate and hence the discharge displacement of the compressor. In addition, although the control chamber of this embodiment consists of a crank chamber, in the modification, it may be a pressure chamber separately provided outside the crank chamber or the crank chamber.

  The control valve 1 is configured as a so-called Ps sensing valve that controls the flow rate of the refrigerant introduced from the discharge chamber to the control chamber so as to maintain the suction pressure Ps of the compressor (corresponding to "sensed pressure") at the set pressure. There is. The control valve 1 is configured by integrally assembling the valve body 2 and the solenoid 3. The valve body 2 is a main valve that opens and closes a refrigerant passage for introducing a part of the discharged refrigerant into the control chamber during operation of the compressor, and a so-called bleed valve for releasing the refrigerant in the control chamber to the suction chamber when the compressor is activated. And a functioning secondary valve. The solenoid 3 drives the main valve in the opening and closing direction to adjust its opening degree, and controls the flow rate of the refrigerant introduced into the control chamber. The valve body 2 includes a stepped cylindrical body 5, a main valve and a sub valve provided inside the body 5, a power element 6 that generates a force against the solenoid force to adjust the opening degree of the main valve, etc. Is equipped. The power element 6 functions as a "pressure sensing unit".

  The body 5 is provided with ports 12, 14, 16 from the upper end side. The port 12 functions as a "suction chamber communication port" and communicates with the suction chamber of the compressor. The port 14 functions as a "control chamber communication port" and communicates with the control chamber of the compressor. The port 16 functions as a "discharge chamber communication port" and communicates with the discharge chamber of the compressor. The end member 13 is fixed so as to close the upper end opening of the body 5. The lower end of the body 5 is connected to the upper end of the solenoid 3.

  In the body 5, a main passage which is an internal passage for communicating the port 16 with the port 14 and a sub passage which is an internal passage for communicating the port 14 with the port 12 are formed. A main valve is provided in the main passage, and a sub valve is provided in the sub passage. That is, the control valve 1 has a configuration in which the power element 6, the auxiliary valve, the main valve, and the solenoid 3 are arranged in order from one end side. A main valve hole 20 and a main valve seat 22 are provided in the main passage. An auxiliary valve hole 32 and an auxiliary valve seat 34 are provided in the auxiliary passage.

  The port 12 brings the working chamber 23 partitioned at the top of the body 5 into communication with the suction chamber. The power element 6 is disposed in the working chamber 23. The port 16 introduces a refrigerant of discharge pressure Pd from the discharge chamber. A main valve chamber 24 is provided between the port 16 and the main valve hole 20, and a main valve is disposed. The port 14 guides the refrigerant, which has become the control pressure Pc via the main valve during steady operation of the compressor, toward the control chamber, while the refrigerant of the control pressure Pc discharged from the control chamber is activated when the compressor is started. Introduce. An auxiliary valve chamber 26 is provided between the port 14 and the main valve hole 20, and an auxiliary valve is disposed. The auxiliary valve chamber 26 functions as a "volume chamber". The port 12 introduces refrigerant of suction pressure Ps during steady operation of the compressor, and draws refrigerant of suction pressure Ps toward the suction chamber via the sub valve when the compressor is activated.

  That is, when the main valve is opened, the port 16 functions as an "introduction port" for introducing the refrigerant from the discharge chamber, and the port 14 as an "extraction port" for discharging the refrigerant toward the control chamber. Function. On the other hand, when the sub valve is opened, the port 14 functions as an "introduction port" for introducing the refrigerant from the control chamber, and the port 12 as an "extraction port" for discharging the refrigerant toward the suction chamber. Function. The port 14 functions as an “in / out port” for introducing or leading out the refrigerant depending on the open / close state of the main valve and the sub valve.

  A main valve hole 20 is provided between the main valve chamber 24 and the sub valve chamber 26, and a main valve seat 22 is formed at the lower end opening end thereof. A guide hole 25 is provided between the port 14 and the working chamber 23. A guide hole 27 is provided in the lower portion of the body 5 (the side opposite to the main valve hole 20 of the main valve chamber 24). A stepped cylindrical valve drive body 29 is slidably inserted in the guide hole 27.

  The upper half portion of the valve driving body 29 is reduced in diameter to be a dividing portion 33 which divides the main valve hole 20 and divides the inside and the outside. A stepped portion formed at an intermediate portion of the valve drive body 29 is a main valve body 30 which is attached to and detached from the main valve seat 22 to open and close the main valve. The main valve body 30 is attached to and detached from the main valve seat 22 from the main valve chamber 24 side to open and close the main valve, and adjust the flow rate of the refrigerant flowing from the discharge chamber to the control chamber. The diameter of the upper portion of the partition 33 is tapered upward, and the sub valve seat 34 is formed at the upper end opening. The auxiliary valve seat 34 functions as a movable valve seat that is displaced together with the valve driver 29. In the present embodiment, the valve drive body 29 and the main valve body 30 are distinguished, but the valve drive body 29 may be regarded as a "main valve body".

  On the other hand, a cylindrical auxiliary valve body 36 is slidably inserted in the guide hole 25. An internal passage of the sub valve body 36 is a sub valve hole 32. The internal passage brings the auxiliary valve chamber 26 and the working chamber 23 into communication by opening the auxiliary valve. The sub valve body 36 and the sub valve seat 34 are disposed to face each other in the axial direction. The sub valve body 36 is attached to and detached from the sub valve seat 34 in the sub valve chamber 26 to open and close the sub valve.

  In addition, an elongated operating rod 38 is provided along the axis of the body 5. The upper end of the actuating rod 38 is operatively connected to the power element 6 through the secondary valve body 36. The lower end portion of the actuating rod 38 is connected to a plunger 50 described later of the solenoid 3. The upper half of the actuating rod 38 passes through the valve driver 29 and the upper portion thereof is reduced in diameter. The sub valve body 36 is extrapolated to the reduced diameter portion and fixed by press fitting. The tip of the reduced diameter portion is connected to the power element 6.

  A ring-shaped spring receiver 40 is fitted and supported at an axially intermediate portion of the actuating rod 38. Between the valve driver 29 and the spring receiver 40, a spring 42 (functioning as a "second biasing member") for biasing the valve driver 29 in the closing direction of the main valve and the sub valve is interposed. It is done. At the time of control of the main valve, the valve drive body 29 and the spring receiver 40 are in a stretched state by the elastic force of the spring 42, and the main valve body 30 and the operation rod 38 operate integrally.

  The power element 6 includes a bellows 45 that senses and displaces the suction pressure Ps, and the displacement of the bellows 45 generates a force against the solenoid force. The counter force is also transmitted to the main valve body 30 via the actuating rod 38 and the auxiliary valve body 36. When the sub valve body 36 is seated on the sub valve seat 34 to close the sub valve, the relief of the refrigerant from the control chamber to the suction chamber is shut off. Further, by the sub valve body 36 being separated from the sub valve seat 34 and opening the sub valve, relief of the refrigerant from the control chamber to the suction chamber is permitted.

  On the other hand, the solenoid 3 has a stepped cylindrical core 46, a bottomed cylindrical sleeve 48 assembled so as to seal the lower end opening of the core 46, and the sleeve 48 housed in the axial direction of the core 46 A stepped cylindrical plunger 50 disposed opposite to each other, a cylindrical bobbin 52 externally fitted to the core 46 and the sleeve 48, and an electromagnetic coil 54 wound around the bobbin 52 and generating a magnetic circuit by energization. A cylindrical case 56 provided so as to cover the electromagnetic coil 54 from the outside, an end member 58 provided so as to seal the lower end opening of the case 56, and embedded in the end member 58 below the bobbin 52 And a collar 60 made of the magnetic material. The core 46, the case 56 and the collar 60 constitute a yoke. Further, the body 5, the end member 13, the core 46, the case 56 and the end member 58 form a body of the control valve 1 as a whole.

  The valve body 2 and the solenoid 3 are fixed by pressing the lower end portion of the body 5 into the upper end opening portion of the core 46. An operating chamber 28 is formed between the core 46 and the valve driver 29. On the other hand, the actuating rod 38 is inserted so as to penetrate the center of the core 46 in the axial direction. The working chamber 28 communicates with the working chamber 23 via the internal passages of the valve driver 29 and the sub valve body 36, respectively. Therefore, the suction pressure Ps of the working chamber 23 is introduced into the working chamber 28. The suction pressure Ps is also led to the inside of the sleeve 48 through the communication passage 62 formed by the gap between the actuating rod 38 and the core 46.

  A spring 44 (functioning as a "first biasing member") is interposed between the core 46 and the plunger 50 to bias the two away from each other. The spring 44 functions as a so-called off spring which opens the main valve when the solenoid 3 is off. The actuating rod 38 is coaxially connected to each of the sub valve body 36 and the plunger 50. The upper portion of the actuating rod 38 is press-fitted to the sub valve body 36 and the lower end portion is press-fitted to the upper portion of the plunger 50. The actuating rod 38, the sub valve body 36 and the plunger 50 constitute a "movable member" which is integrally displaced with the valve driver 29 at the time of control of the main valve.

  The actuating rod 38 appropriately transmits the solenoid force, which is the attraction between the core 46 and the plunger 50, to the main valve body 30 and the sub valve body 36. On the other hand, the operating rod 38 is loaded such that the driving force (also referred to as “pressure-sensitive driving force”) by the expansion and contraction operation of the power element 6 opposes the solenoid force. That is, in the control state of the main valve, a force adjusted by the solenoid force and the pressure-sensitive driving force acts on the main valve body 30, and the opening degree of the main valve is appropriately controlled. At startup of the compressor, the actuating rod 38 is displaced relative to the body 5 against the biasing force of the spring 44 according to the magnitude of the solenoid force, and after closing the main valve, the sub valve body 36 is pushed up to Open the valve. Further, even during control of the main valve, when the suction pressure Ps is considerably increased, the actuating rod 38 is displaced relative to the body 5 against the biasing force of the bellows 45, and after the main valve is closed, the sub valve The body 36 is pushed up to open the sub valve. The bleed function is thereby exhibited.

  The sleeve 48 is made of nonmagnetic material. A communication groove 66 parallel to the axis is provided on the side surface of the plunger 50, and a communication hole 68 communicating the inside and the outside is provided on the lower portion of the plunger 50. With such a configuration, even when the plunger 50 is located at the bottom dead center as shown, the suction pressure Ps is guided to the back pressure chamber 70 through the gap between the plunger 50 and the sleeve 48.

  A pair of connection terminals 72 connected to the electromagnetic coil 54 extend from the bobbin 52 and extend through the end members 58 and are drawn to the outside. Only one of the pair is shown in FIG. The end member 58 is attached so as to seal the entire structure in the solenoid 3 contained in the case 56 from below. The end member 58 is formed by molding (injection molding) of a resin material having corrosion resistance, and the resin material is also filled in the gap between the case 56 and the electromagnetic coil 54. Thus, the resin material fills the gap between the case 56 and the electromagnetic coil 54 with the resin material, so that the heat generated by the electromagnetic coil 54 can be easily transmitted to the case 56, and the heat dissipation performance thereof is enhanced. The tip of the connection terminal 72 is drawn out from the end member 58 and connected to an external power supply (not shown).

FIG. 2 is a partially enlarged cross-sectional view corresponding to the upper half of FIG.
A labyrinth seal 74 formed of a plurality of annular grooves for suppressing the flow of the refrigerant is provided on the sliding surface of the valve driver 29 with the guide hole 27. The spring receiver 40 is a so-called E-ring, is supported so as to fit in an annular groove formed in the middle of the actuating rod 38, and is disposed in the actuating chamber 28.

  The lower half of the valve driver 29 has an enlarged inner diameter, and the spring 42 is disposed so as to be accommodated in the enlarged diameter portion. With such a configuration, the contact point between the spring 42 and the valve driving body 29 is located closer to the main valve chamber 24 than the center of the sliding portion in the guide hole 27, so the valve driving body 29 is Is stably supported by the spring 42 in the manner as described above. As a result, it is possible to prevent or suppress the generation of hysteresis due to wobble when the main valve body 30 is driven to open and close.

  The sub valve body 36 has an insertion hole 43 axially penetrating the center thereof. The upper portion of the actuating rod 38 extends through the insertion hole 43 to the power element 6. The sub valve body 36 is positioned relative to the actuating rod 38 by being locked to the step 79 which is the proximal end of the reduced diameter portion of the actuating rod 38. A plurality of internal passages 39 for communicating the internal passage 37 of the valve drive body 29 with the working chamber 23 are formed around the insertion hole 43 in the sub valve body 36. The internal passage 39 extends in parallel with the insertion hole 43 and penetrates the sub valve body 36. A labyrinth seal 75 is provided on the sliding surface of the sub valve body 36 with the guide hole 25. In the illustrated state where the auxiliary valve body 36 is seated on the auxiliary valve seat 34, the actuating rod 38 is separated such that the upper surface of the spring receiver 40 is separated from the lower surface of the valve drive body 29 by at least a predetermined distance L. The position of the step 79 is set. The predetermined interval L functions as so-called "play".

  When the solenoid force is increased, the actuating rod 38 can be displaced relative to the main valve body 30 (valve driver 29) to push up the sub valve body 36. Thereby, the sub valve body 36 and the sub valve seat 34 can be separated to open the sub valve. Further, the solenoid force can be directly transmitted to the main valve body 30 in a state in which the spring receiver 40 and the valve drive body 29 are engaged (contact), and the main valve body 30 is closed in the main valve closing direction. Can be pressed with a large force. This configuration functions as an unlocking mechanism that unlocks the operation of the main valve body 30 due to the trapping of foreign matter in the sliding portion between the valve driver 29 and the guide hole 27.

  The main valve chamber 24 is provided coaxially with the body 5 and configured as a pressure chamber having a diameter larger than that of the main valve hole 20. Therefore, a relatively large space is formed between the main valve and the port 16, and a sufficient flow rate of the refrigerant flowing through the main passage can be secured when the main valve is opened. Similarly, the sub valve chamber 26 is also provided coaxially with the body 5 and configured as a pressure chamber having a diameter larger than that of the main valve hole 20. For this reason, a relatively large space is also formed between the sub valve and the port 14. Then, as shown in the drawing, the attachment / detachment portion between the upper end of the valve drive body 29 and the lower end of the sub valve body 36 is set to be positioned at the central portion of the sub valve chamber 26. That is, the movable range of the main valve body 30 is set so that the sub valve seat 34 is always positioned in the sub valve chamber 26, and the sub valve is opened and closed in the sub valve chamber 26. Therefore, when the sub valve is opened, the flow rate of the refrigerant flowing through the sub passage can be sufficiently secured. That is, the bleeding function can be effectively exhibited.

  The power element 6 is configured by closing the upper end opening of the bellows 45 with a first stopper 82 and closing the lower end opening with a second stopper 84. The bellows 45 functions as a "pressure-sensitive member", and the first stopper 82 and the second stopper 84 each function as a "base member". The first stopper 82 is coaxially supported by the end member 13. The stoppers 82 and 84 are formed into a bottomed cylindrical shape by press-forming a metal material, and have a flange portion 86 extending radially outward at the open end thereof. The bellows 45 has a bellows-like main body, and the upper end opening of the main body is airtightly welded to the flange 86 of the first stopper 82, and the lower end opening of the main body is airtight to the flange 86 of the second stopper 84 Are welded to. The inside of the bellows 45 is a sealed reference pressure chamber S, and a spring 88 urging the bellows 45 in the extension direction between the first stopper 82 and the second stopper 84 inward of the bellows 45. Is interspersed. The reference pressure chamber S is in a vacuum state in the present embodiment.

  The end member 13 is a fixed end of the power element 6. At the center of the lower surface of the end member 13, a support portion 89 protrudes downward. The support portion 89 is coaxially fitted to the first stopper 82 and supports the first stopper 82 from above. The distal end of the support portion 89 locks the bottom of the first stopper 82 to restrict the upward displacement of the power element 6. The set load of the power element 6 (set load of the spring 88) can be adjusted by adjusting the press-fit amount to the body 5.

  The central portion of the first stopper 82 extends downward to the inward of the bellows 45, and the central portion of the second stopper 84 extends upward to the inward of the bellows 45, which are the axes of the bellows 45 It forms a core. The upper end of the actuating rod 38 is fitted to the second stopper 84. The bellows 45 extends or contracts in the axial direction (opening and closing directions of the main valve and the auxiliary valve) in accordance with the differential pressure between the suction pressure Ps of the working chamber 23 and the reference pressure of the reference pressure chamber S. According to the displacement of the bellows 45, a driving force in the valve opening direction is applied to the main valve body 30. Even if the differential pressure increases, when the bellows 45 is contracted by a predetermined amount, the second stopper 84 abuts on and is locked to the first stopper 82, so that the contraction is regulated.

  In the present embodiment, the effective pressure receiving diameter A of the bellows 45, the effective pressure receiving diameter B (seal portion diameter) of the main valve of the main valve body 30, and the sliding portion diameter C (seal portion diameter) of the valve driver 29. The sliding portion diameter D (seal portion diameter) of the sub valve body 36 is set to be equal. Here, "equal" may be regarded as including almost equal (substantially equal) concepts as well as completely equal concepts. For this reason, in the state where the valve driving body 29 and the power element 6 are operatively connected, the influence of the discharge pressure Pd, the control pressure Pc and the suction pressure Ps acting on the combined body of the main valve body 30 and the sub valve body 36 It is canceled. As a result, in the control state of the main valve, the main valve body 30 opens and closes based on the suction pressure Ps that the power element 6 receives in the working chamber 23. That is, the control valve 1 functions as a so-called Ps sensing valve.

  In this embodiment, while making the diameters B, C, and D equal as described above, the pressure acting on the valve body by vertically penetrating the internal passage of the valve body (the main valve body 30 and the sub valve body 36) The effects of Pd, Pc, Ps) can be canceled. That is, the pressure before and after (up and down in the figure) of the combination of the sub valve body 36, the valve drive body 29, the operating rod 38 and the plunger 50 can be made the same pressure (suction pressure Ps), thereby realizing pressure cancellation. Be done. Thereby, the diameter of each valve body can be set independently of the diameter of the bellows 45, and the design freedom is high. Therefore, in the modification, the diameters B, C, and D may be made equal, while the effective pressure receiving diameter A may be made different from these. That is, the effective pressure receiving diameter A of the bellows 45 may be smaller than the diameters B, C, D, or may be larger than the diameters B, C, D.

  On the other hand, in the present embodiment, the seal portion diameter E in the sub valve of the sub valve body 36 is smaller than the seal portion diameter effective pressure receiving diameter B in the main valve of the main valve body 30, and the control pressure Pc and the suction pressure Ps The differential pressure (Pc−Ps) acts on the valve driver 29 in the valve opening direction of the sub valve. Such a pressure receiving structure and an urging structure by the spring 42 realize a “differential pressure opening mechanism” that opens the sub valve when the differential pressure (Pc−Ps) becomes equal to or higher than the set differential pressure ΔPset. There is.

  An O-ring 92 is fitted between the port 12 and the port 14 on the outer peripheral surface of the body 5, and an O-ring 94 is fitted between the port 14 and the port 16. Furthermore, an O-ring 96 is also fitted to the outer peripheral surface near the upper end of the core 46. These O-rings 92, 94, 96 have a sealing function, and restrict the refrigerant leakage when the control valve 1 is mounted in the mounting hole of the compressor.

Next, the operation of the control valve will be described.
In the present embodiment, a PWM (Pulse Width Modulation) method is adopted to control energization of the solenoid 3. The PWM control is performed by supplying a pulse current of about 400 Hz set to a predetermined duty ratio to perform control, and is executed by a control unit (not shown). Although this control unit has a PWM output unit for outputting a pulse signal of a designated duty ratio, a well-known one is adopted as the configuration itself, and therefore detailed description will be omitted.

  3 to 5 are diagrams showing the operation of the control valve. FIG. 2 already described shows the minimum displacement operating state of the control valve. FIG. 3 shows a state in which the bleed function is operated at the time of activation of the control valve or the like. FIG. 4 shows a relatively stable control state. FIG. 5 shows a state when the control pressure Pc becomes excessive when the solenoid 3 is off. Below, based on FIG. 1, it demonstrates, referring FIGS. 2-5 suitably.

  When the solenoid 3 is not energized (turned off) in the control valve 1, that is, when the automotive air conditioner is not operating, no suction force acts between the core 46 and the plunger 50. On the other hand, the biasing force of the spring 44 is transmitted to the valve driver 29 through the plunger 50, the operating rod 38 and the sub valve body 36. As a result, as shown in FIG. 2, the main valve body 30 is separated from the main valve seat 22, and the main valve is fully opened. At this time, the sub valve maintains the closed state.

  On the other hand, when the activation current is supplied to the electromagnetic coil 54 of the solenoid 3 at the time of activation of the automotive air conditioning system, as shown in FIG. If the pressure is higher than “pressure”, the sub valve opens. That is, the solenoid force overcomes the biasing force of the spring 42, and the sub valve body 36 is integrally pushed up. As a result, the auxiliary valve body 36 is separated from the auxiliary valve seat 34, the auxiliary valve is opened, and the bleeding function is effectively exhibited. In this operation process, the main valve body 30 is pushed up by the biasing force of the spring 42 and is seated on the main valve seat 22. As a result, the main valve is closed. That is, after the main valve is closed to restrict the introduction of the discharge refrigerant into the control chamber, the sub valve is opened to quickly relieve the refrigerant in the control chamber to the suction chamber. As a result, the compressor can be started quickly. The “sub valve opening pressure” changes in accordance with a change in a set pressure Pset described later according to the environment where the vehicle is placed.

  When the current value supplied to the solenoid 3 is within the control current value range of the main valve, the opening degree of the main valve is autonomously adjusted so that the suction pressure Ps becomes the set pressure Pset set by the supply current value. In the control state of the main valve, as shown in FIG. 4, the sub valve body 36 is seated on the sub valve seat 34, and the sub valve maintains the closed state. On the other hand, since the suction pressure Ps is relatively low, the bellows 45 extends, and the main valve body 30 operates to adjust the opening degree of the main valve. At this time, the main valve body 30 is at the valve lift position where the force in the valve opening direction by the spring 44, the solenoid force in the valve closing direction, and the force in the valve opening direction by the power element 6 according to the suction pressure Ps are balanced. Stop.

  Then, for example, when the refrigeration load becomes large and the suction pressure Ps becomes higher than the set pressure Pset, the bellows 45 shrinks, so the main valve body 30 is displaced relatively upward (valve closing direction). As a result, the valve opening degree of the main valve becomes smaller, and the compressor operates to increase the displacement. As a result, the suction pressure Ps changes in the decreasing direction. Conversely, when the refrigeration load decreases and the suction pressure Ps becomes lower than the set pressure Pset, the bellows 45 extends. As a result, the power element 6 biases the main valve body 30 in the valve opening direction to increase the valve opening degree of the main valve, and the compressor operates to reduce the displacement. As a result, the suction pressure Ps is maintained at the set pressure Pset. When the suction pressure Ps becomes considerably higher than the set pressure Pset, depending on the height of the suction pressure Ps, it is also assumed that the main valve closes and the sub valve opens. However, since there is a pressure range (dead zone) from the time the main valve is closed to the time the sub valve is opened, the situation where the main valve and the sub valve are opened and closed unstably is prevented.

  When it is desired to reduce the load on the air conditioner while the steady control is being performed, the solenoid 3 is switched from on to off in the control valve 1. Then, since the suction force does not act between the core 46 and the plunger 50, the main valve body 30 is separated from the main valve seat 22 by the biasing force of the spring 44, and the main valve is fully opened. At this time, since the sub valve body 36 is basically seated on the sub valve seat 34, the sub valve is closed. As a result, the refrigerant of discharge pressure Pd introduced from the discharge chamber of the compressor to the port 16 passes through the fully opened main valve and flows from the port 14 to the control chamber. Therefore, the control pressure Pc becomes high, and the compressor performs the minimum capacity operation.

  However, when the differential pressure (Pc−Ps) becomes equal to or higher than the set differential pressure ΔPset at the time of switching to the minimum displacement operation, as shown in FIG. 5, the differential pressure opening mechanism operates. That is, the force due to the differential pressure (Pc-Ps) overcomes the biasing force of the spring 42 and pushes the valve driver 29 downward to open the sub valve. For this reason, it is possible to prevent or suppress the sudden increase of the control pressure Pc. As the set differential pressure ΔPset, a value exceeding the maximum value of the differential pressure (Pc−Ps) that can act on the valve drive body 29 during the stable control of the main valve is set. For this reason, the auxiliary valve is basically not opened during control of the main valve. The opening of the auxiliary valve by the differential pressure opening mechanism is different from the forced opening mechanism of the auxiliary valve by the solenoid 3 shown in FIG. 3 in that the opening of the auxiliary valve is realized when the main valve is opened.

  In the present embodiment, since the main valve body 30 and the sub valve seat 34 are integrally provided with respect to the valve drive body 29, while the sub valve is opened by the operation of the differential pressure valve opening mechanism, the opening degree of the main valve is also To increase. Moreover, the seal portion diameter of the main valve is larger than the seal portion diameter of the sub valve. For this reason, there is also a view that it is difficult to expect the effect of the differential pressure valve-opening mechanism when focusing only on the magnitude of the opening degree of the main valve and the sub-valve. However, the compressor is generally provided with an orifice (also referred to as "a leak orifice") for communicating the control chamber and the suction chamber separately from the sub valve of the control valve 1, and the refrigerant in the control chamber is taken to the suction chamber side. Always leak. The synergetic effect of the functions of the leakage orifice and the differential pressure valve opening mechanism makes it possible to suppress the increase in the control pressure Pc as a whole. As described later, in the modification, the main valve body and the auxiliary valve seat may be separately provided, so that the effect of the differential pressure valve opening mechanism may be directly obtained.

  FIG. 6 is a view showing the valve opening characteristic of the control valve 1. (A) shows the valve opening characteristic of the auxiliary valve, the horizontal axis shows the auxiliary valve stroke (lift of the auxiliary valve body 36 from the auxiliary valve seat 34), and the vertical axis shows the opening area of the auxiliary valve. (B) shows the valve opening characteristic of the sub valve, the horizontal axis shows the suction pressure Ps, and the vertical axis shows the sub valve stroke. (C) shows the valve opening characteristics of the main valve and the secondary valve, the horizontal axis shows the suction pressure Ps, and the vertical axis shows the opening area of each valve. When the supplied current value is constant, the magnetic gap of the solenoid 3 increases as the suction pressure Ps decreases, and the magnetic gap decreases as the suction pressure Ps increases.

  As shown in FIG. 6A, the amount of change in the opening area of the sub valve is set to be small after the sub valve starts to open, that is, in a small stroke area, and to increase after reaching a predetermined stroke. There is. This is because, as shown in FIG. 3 and the like, the contact surface between the sub valve seat 34 and the sub valve body 36 is tapered with respect to the axis. With such a configuration, even if the auxiliary valve is slightly opened during control of the main valve, the influence on the control can be reduced. That is, since PWM control is adopted in the present embodiment, there is a possibility that the auxiliary valve may open due to the vibration. For example, if the main valve body 30 strikes the main valve seat 22 when the main valve is fully opened, the impact may open the sub valve. This possibility is particularly high when the load of the spring 42 is set smaller. In such a case, even if the auxiliary valve is slightly opened, the control of the main valve is not substantially affected.

  On the other hand, as shown in FIG. 6B, the auxiliary valve stroke is set to change linearly (proportionally) with respect to the suction pressure Ps. By doing this, as shown in FIG. 6 (C), when the suction pressure Ps rises and exceeds a certain value, the auxiliary valve is made to largely open. As a result, the bleed function is promptly exhibited in the state where the suction pressure Ps is high, and the air conditioning function is efficiently obtained.

  As described above, in the present embodiment, when the differential pressure (Pc−Ps) between the control pressure Pc and the suction pressure Ps becomes equal to or higher than the set differential pressure ΔPset by turning off the solenoid 3, the differential pressure valve opening mechanism operates. The secondary valve is opened. As a result, it is possible to prevent or suppress the control pressure Pc from rising excessively, and to avoid problems such as the refrigerant leaking from the seal portion inside the compressor to the outside.

  Further, in the present embodiment, the amount of change in the opening area of the auxiliary valve is reduced in the region where the auxiliary valve starts to open, so it may be assumed that the auxiliary valve is opened during control of the main valve. Also, the control of the main valve is not affected. When the main task is to "do not affect the control performance of the main valve by opening the sub valve" as described above, the above-described differential pressure valve opening mechanism is not essential. Good.

Second Embodiment
FIG. 7 is a view showing the valve opening characteristic of the control valve according to the second embodiment. (A) shows the valve opening characteristic of the auxiliary valve, the horizontal axis shows the auxiliary valve stroke, and the vertical axis shows the opening area of the auxiliary valve. (B) shows the valve opening characteristic of the sub valve, the horizontal axis shows the suction pressure Ps, and the vertical axis shows the sub valve stroke. Hereinafter, differences from the first embodiment will be mainly described.

  The present embodiment differs from the first embodiment in the valve opening characteristic of the sub valve. That is, as shown in FIG. 7A, the change amount of the opening area of the sub valve is set to change linearly (proportionally) from the start of opening of the sub valve to reaching the fully open state. This setting can be realized, for example, by making the contact surface between the sub valve seat 34 and the sub valve body 36 a plane perpendicular to the axis in FIG.

  On the other hand, as shown in FIG. 7 (B), the opening degree of the sub valve gradually increases as the suction pressure Ps becomes higher, and the valve opening characteristic is changed so that it suddenly changes to a fully open state at a predetermined full open pressure. Is set. Such valve opening characteristics can be set by the relationship between the suction force characteristics of the solenoid 3 and the driving force characteristics (load characteristics) of the power element 6. Specifically, as a characteristic for the magnetic gap of the solenoid 3 which changes according to the suction pressure Ps, the inclination of the attraction force characteristic of the solenoid 3 is set larger than the inclination of the drive force characteristic of the power element 6 at the full open pressure. By doing this, the above-mentioned valve opening characteristic can be realized. In the modification, as the valve opening characteristic of the sub valve, for example, the characteristic shown in FIG. 6A and the characteristic shown in FIG. 7B may be set.

  The same effect as that of the first embodiment can be obtained also by the present embodiment and the modification. Further, as in the first embodiment, the problem of "preventing the control performance of the main valve from being opened by the sub valve" can be addressed.

Third Embodiment
FIG. 8 is a view showing the valve opening characteristic of the control valve according to the third embodiment. (A) shows the valve opening characteristic of this embodiment, (B) shows the valve opening characteristic of a comparative example. The upper part of each drawing shows the setting of the dead zone in which both the main valve and the auxiliary valve are closed, and the lower part shows the open / close state of each valve according to the setting. In each figure, the horizontal axis indicates the suction pressure Ps, and the vertical axis indicates the valve stroke. Hereinafter, differences from the first embodiment will be mainly described.

  In the present embodiment, the "dead zone" in which both valves are closed after the main valve is closed until the sub-valve is opened is set small, and the springback of the main valve body 30 to the main valve seat 22 is suppressed. That is, in the control valve in which the above-described PWM control is performed, the main valve body 30 strokes while slightly vibrating in accordance with the frequency (for example, about 400 Hz). Therefore, when the dead zone is set large as in the comparative example shown in FIG. 8B (upper stage in FIG. 8B), when the main valve is in the slightly open state, the main valve body 30 is mainly There is a possibility that the valve seat 22 is hit and rebounded by reaction (FIG. 8 (B) lower stage). In addition, the space | interval of the continuous line and dashed-two dotted line in a figure has illustrated the amplitude of each valve body. If the opening degree of the main valve becomes large due to the springback of the main valve body 30 (see the alternate long and short dash line), there is a possibility that an unintended suction pressure Ps may be increased.

  Therefore, in the present embodiment, as shown in FIG. 8A, by setting the dead zone small (the upper stage in FIG. 8A), the sub-valve is made easy to open in the open state of the main valve. With such a configuration, even if the main valve 30 tries to bounce back to increase the opening degree of the main valve, the increase of the control pressure Pc and hence the suction pressure Ps can be suppressed by opening the sub valve (FIG. 8 (A ) Bottom). In addition, the space | interval of the continuous line and dashed-two dotted line in a figure has illustrated the amplitude of each valve body. In other words, the collision energy of the main valve body 30 can be released as the operation energy of the sub valve. Such stabilization of the control pressure Pc consequently absorbs the vibration of the main valve body 30 and suppresses its rebound. As a result, an unintended increase in suction pressure Ps is suppressed.

  In this way, if the sub-valve is made easy to open in the state where the main valve is opened, for example, the leakage orifice of the compressor can be made smaller. As a result, when the solenoid 3 is turned off, the compressor can be rapidly shifted to the minimum displacement operation, and the operating efficiency of the air conditioner can be enhanced. The size of this "dead zone" can be set by the load of the spring 42, and can be set, for example, to such an extent that the auxiliary valve starts to open when the main valve is fully opened (before the main valve is completely closed). Specifically, the dead zone may be set so that the sub valve starts to open when the main valve body 30 enters a range where the main valve body 30 strikes the main valve seat 22 due to vibration due to PWM control. Alternatively, when the opening degree of the main valve becomes equal to or less than the amplitude by the PWM control, the dead zone may be set so that the sub valve starts to open before the main valve is completely closed. According to the present embodiment, the main valve and the sub valve are simultaneously opened before the main valve is completely closed.

  Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and it goes without saying that various modifications are possible within the scope of the technical idea of the present invention. Absent.

  Although not described in the above embodiment, the combined size of the maximum opening area of the sub valve and the opening area of the leakage orifice may be configured to be larger than the maximum opening area of the main valve. In addition, the total flow rate of the refrigerant flowing through the sub valve and the leakage orifice may be configured to be larger than the flow rate flowing through the main valve when the main valve is fully open when the sub valve is fully opened. With such a configuration, for example, even when the operation of the main valve body is locked when the main valve is fully open, the control pressure Pc can be reduced to some extent to start the compressor. That is, the air conditioning function of the air conditioner can be secured to some extent.

  In the said embodiment, the example in which the main valve body 30 and the sub valve seat 34 were provided integrally was shown. In a variant, these may be configured separately from one another. Specifically, a valve drive body may be provided separately from the main valve body 30, and the sub valve seat 34 may be formed on the valve drive body to be a "movable valve seat". Also in this case, when the differential pressure (Pc−Ps) becomes equal to or higher than the set differential pressure ΔPset, the sub valve is opened by displacing the valve driving body.

  In the above embodiment, an example in which the sub valve body 36 is fixed to the actuating rod 38 has been shown. In a modification, both may be configured to be relatively displaceable. Specifically, a spring (functioning as a "biasing member") slidably inserting the sub valve body 36 shown in FIG. 2 into the actuating rod 38 and biasing the sub valve body 36 in the valve closing direction is used. You may intervene. For example, a spring may be interposed between the sub valve body 36 and the power element 6. However, the displacement of the sub valve body 36 in the valve closing direction is regulated by the step 79 of the actuating rod 38. In such a configuration, when the differential pressure (Pc−Ps) becomes equal to or higher than the set differential pressure ΔPset, the load by the set differential pressure ΔPset exceeds the load of the spring, and the direction in which the sub valve body 36 separates from the sub valve seat 34 May be displaced. With such a configuration, when the differential pressure (Pc−Ps) becomes equal to or higher than the set differential pressure ΔPset, the sub valve can be opened larger, and the effect of suppressing the increase in the control pressure Pc can be enhanced.

  In the above embodiment, as shown in FIG. 2, an example is shown in which the spring 42 is interposed between the valve drive body 29 and the actuating rod 38. In a variant, a spring 42 may be interposed between the valve driver 29 and the core 46 (body of the control valve 1).

  In the above embodiment, as the control valve, the power element 6 is disposed in the working chamber 23 in which the suction pressure Ps is satisfied, and the so-called Ps sensing valve which operates by directly sensing the suction pressure Ps is illustrated. In a modification, it may be a so-called Pc sensing valve which operates by sensing not the suction pressure Ps but the control pressure Pc as a sensed pressure. Alternatively, without providing the power element, the movable member including the valve body may be configured as a differential pressure valve that operates by sensing a differential pressure. For example, it may be a Pd-Ps differential pressure valve which operates so that the differential pressure (Pd-Ps) between the discharge pressure Pd and the suction pressure Ps becomes the set differential pressure. Alternatively, it may be a Pd-Pc differential pressure valve which operates so that the differential pressure (Pd-Pc) between the discharge pressure Pd and the control pressure Pc becomes the set differential pressure.

  Although the example which employ | adopts the bellows 45 as a pressure-sensitive member which comprises the power element 6 was shown in the said embodiment, you may employ | adopt a diaphragm. In that case, a plurality of diaphragms may be connected in the axial direction in order to secure an operation stroke necessary for the pressure-sensitive member.

  Although the spring is illustrated as the biasing member (elastic body) in the above embodiment regarding the springs 42, 44, etc., it goes without saying that an elastic material such as rubber or resin may be employed.

  In the above embodiment, although the reference pressure chamber S inside the bellows 45 is in a vacuum state, it may be filled with the atmosphere or may be filled with a predetermined gas as a reference. Alternatively, one of the discharge pressure Pd, the control pressure Pc, and the suction pressure Ps may be satisfied. Then, the power element may be configured to operate by appropriately detecting the pressure difference between the inside and the outside of the bellows. Further, in the above embodiment, although the pressure Pd, Pc, Ps directly received by the main valve body is canceled, at least one of these pressures may not be canceled.

  The present invention is not limited to the above-described embodiment and modification, and the components can be modified and embodied without departing from the scope of the invention. Various inventions may be formed by appropriately combining a plurality of components disclosed in the above-described embodiment and modifications. Moreover, some components may be deleted from all the components shown in the above-mentioned embodiment and modification.

Reference Signs List 1 control valve, 3 solenoid, 5 body, 6 power element, 12 port, 14 port, 16 port, 22 main valve seat, 23 operation chamber, 24 main valve chamber, 25 guide hole, 26 sub valve chamber, 27 guide hole, 28 working chamber, 29 valve driver, 30 main valve body, 34 sub valve seat, 36 sub valve body, 38 actuating rod.

Claims (3)

Control for a variable displacement compressor that changes the discharge capacity of a variable displacement compressor that compresses the refrigerant introduced into the suction chamber and discharges it from the discharge chamber by adjusting the flow rate of the refrigerant introduced from the discharge chamber to the control chamber A valve,
A main passage communicating the discharge chamber with the control chamber, and a body having a sub passage communicating the control chamber with the suction chamber;
A main valve seat provided on the body in the main passage;
A main valve body slidably supported by the body and detachably attached to the main valve seat to open and close the main valve;
A sub valve seat provided integrally with Oite the main valve body to said auxiliary passage,
An auxiliary valve body that is attached to and detached from the auxiliary valve seat to open and close the auxiliary valve;
A solenoid that generates a driving force in the closing direction of the main valve and in the opening direction of the sub valve ;
The sub valve body is provided integrally with the operating rod for directly transmitting the driving force of the solenoid before Symbol sub-valve body,
A first biasing member for applying a biasing force in the valve opening direction to the main valve;
A second biasing member for applying biasing force in a valve closing direction of the sub valve to the main valve body ;
Equipped with
The solenoid is controlled to be energized by a PWM method.
It is possible to displace the operating rod relative to the main valve body in accordance with the magnitude of the driving force of the solenoid.
After the main valve body starts to sit on the main valve seat while micro-oscillating in the process of increasing the value of the current supplied to the solenoid, the main valve is completely closed while the state of sitting on the main valve seat is maintained. A control valve for a variable displacement compressor, wherein an urging force of the second urging member is set such that a state in which the main valve and the sub valve are simultaneously opened exists before the state is reached.   The biasing force of the second biasing member is set so that the sub valve starts to open when the main valve body enters a range where the main valve body strikes the main valve seat due to vibration due to energization control of the PWM method. The control valve for a variable displacement compressor according to claim 1, characterized in that When the opening degree of the main valve becomes equal to or less than the amplitude of vibration due to the energization control of the PWM method, the second urging member of the second urging member starts to open the sub valve before the main valve is completely closed . The control valve for a variable displacement compressor according to claim 1, wherein a biasing force is set.

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