JP4509000B2 - Pressure control valve - Google Patents

Description

The present invention relates to a pressure control valve that is incorporated in a vapor compression refrigeration cycle (CO ₂ cycle) in which CO ₂ is used as a refrigerant, and regulates the refrigerant pressure on the gas cooler (radiator) outlet side according to the refrigerant temperature, In particular, the present invention relates to a pressure control valve suitable for a vapor compression refrigeration cycle employed in a car air conditioner or the like provided with an internal heat exchanger that performs heat exchange between a refrigerant on an evaporator outlet side and a refrigerant on a gas cooler outlet side.

An example of a vapor compression refrigeration cycle incorporating this type of pressure control valve is shown in FIG. In the illustrated refrigeration cycle 100, a compressor 101 for circulating CO ₂ as a refrigerant, a gas cooler (heat radiator) 102 for cooling the refrigerant compressed by the compressor 101, and a refrigerant from the gas cooler 102 are introduced. The evaporator 104, the internal heat exchanger 103 that performs heat exchange between the refrigerant on the outlet side of the evaporator 104 and the refrigerant on the outlet side of the gas cooler 102, and the refrigerant from the evaporator 104 as a gas phase refrigerant and a liquid phase In addition to the accumulator (gas-liquid separator) 105 that stores the surplus refrigerant, the internal heat is supplied from the gas cooler 102 while the vapor phase refrigerant is separated into the refrigerant and guided to the suction side of the compressor 101 via the heat exchanger 103. A pressure control valve 110 is provided that regulates the refrigerant introduced through the exchanger 103 according to the refrigerant temperature on the outlet side of the gas cooler 102 and leads the refrigerant to the evaporator 104.

  The pressure control valve 110 is provided to efficiently operate the refrigeration cycle 100, in other words, the refrigerant on the outlet side of the gas cooler 102 so that the maximum coefficient of performance is obtained with respect to the refrigerant temperature on the outlet side of the gas cooler 102. The pressure is regulated (for example, when the refrigerant temperature on the outlet side is 40 ° C. and the refrigerant coefficient on the outlet side is, for example, 10 MPa, the coefficient of performance becomes maximum, the refrigerant pressure on the outlet side becomes 10 MPa. A high-pressure refrigerant inlet 111 for introducing the refrigerant from the gas cooler 102 via the internal heat exchanger 103, as described in, for example, the following Patent Document 1 and the like. A low-pressure refrigerant outlet 112 for adjusting the refrigerant according to the refrigerant temperature on the outlet side of the gas cooler 102 and leading the refrigerant to the evaporator 104; A temperature-sensitive inlet 113 for introducing the refrigerant, a temperature-sensitive outlet 114 for introducing the refrigerant to the internal heat exchanger 103, and between the temperature-sensitive inlet 113 and the outlet 114. It has a temperature-sensing chamber (not shown in the figure below) and a temperature-sensing greenhouse that senses the temperature of the refrigerant introduced into the temperature-sensing chamber, and responds to changes in the internal pressure of the temperature-sensing chamber. Temperature-sensitive pressure responsive element that drives the valve body in the opening and closing direction, a valve body that contains this element (the entire control valve shown in the figure), and a direction that is distributed within this valve body to reduce the valve opening (closed) A spring member that urges the valve body in the valve direction), and a valve opening degree (a lift amount of the valve body) is determined by a valve opening force due to a differential pressure inside and outside the greenhouse and a valve closing force due to the spring member. It is determined by the equilibrium relationship.

JP 2001-81157 A JP-A-11-248272

In the pressure control valve used by being incorporated in a vapor compression refrigeration cycle (CO ₂ cycle) such as a car air conditioner as described above, when the outside air temperature is high, that is, by solar radiation or heat from an engine or the like. When the pressure control valve is overheated (usually when it is 50 ° C or lower, for example, 60 ° C or higher), the pressure in the element (greenhouse) rises, and excessive force acts in the valve closing direction. Therefore, it may cause malfunction such as the valve not opening during compressor operation (particularly at startup). As a result, the discharge pressure is increased abnormally, and the internal heat exchanger, gas cooler, There is a risk that the compressor will break down or break down.

In order to avoid this, gas is sealed in the element with MOP (maximum operating pressure) like a normal chlorofluorocarbon pressure control valve. If so-called G charge is possible, it is best, but it is the CO ₂ cycle. In this case, since it is impossible to cope with G charge, a part of the high-pressure refrigerant may be relieved to the low-pressure side (evaporator side) when the high-pressure side of the refrigeration cycle reaches a predetermined pressure (or temperature). (See Patent Document 2 above).

  By the way, in the pressure control valve as described above, in recent years, the demand for cost reduction has become more and more severe, and there is a strong demand for simplification of the configuration, reduction of the number of parts, reduction of processing assembly cost, and the like.

  The present invention has been made to meet the above-mentioned problems and demands, and the object of the present invention is to appropriately adjust the refrigerant pressure on the outlet side of the gas cooler according to the refrigerant temperature on the outlet side, and the configuration Simplification, reduction of the number of parts, reduction of processing and assembly costs, etc., and inability to open the valve due to the pressure in the element rising due to solar radiation and heat from the engine etc. It is an object of the present invention to provide a pressure control valve that can reliably prevent malfunction.

In order to achieve the above object, a pressure control valve according to the present invention basically includes a compressor for circulating CO ₂ as a refrigerant, a gas cooler for cooling a high-pressure refrigerant compressed by the compressor, Steam having an evaporator into which refrigerant from the gas cooler is pressure-adjusted and introduced, and an internal heat exchanger for exchanging heat between the low-pressure refrigerant on the outlet side of the evaporator and the high-pressure refrigerant on the outlet side of the gas cooler A main valve that is incorporated in a compression refrigeration cycle and that regulates high-pressure refrigerant introduced from the gas cooler via the internal heat exchanger according to the refrigerant temperature on the outlet side of the gas cooler and leads it to the evaporator A main valve chamber provided with a main valve seat for contacting and separating the main valve body and
A temperature-sensitive inlet for introducing the high-pressure refrigerant from the gas cooler, a temperature-sensitive outlet for leading it to the internal heat exchanger, and provided between the temperature-sensitive inlet and the outlet. The temperature-sensing introduction chamber, the high-pressure refrigerant inlet for introducing the high-pressure refrigerant from the internal heat exchanger into the main valve chamber, and the refrigerant adjusted to a low pressure by the main valve body are led to the evaporator. A valve body having a low-pressure refrigerant outlet, and a temperature-sensing greenhouse for sensing the temperature of the high-pressure refrigerant introduced into the temperature-sensing introduction chamber, and the main valve body in response to a change in the internal pressure of the temperature-sensing greenhouse A temperature-sensitive pressure responsive element that is driven in the opening and closing direction.

  The valve body is provided with a relief mechanism for allowing a part of the high-pressure refrigerant to escape to the low-pressure refrigerant outlet when the temperature of the high-pressure refrigerant is equal to or higher than a predetermined temperature.

  Preferably, the relief mechanism includes a valve seat passage with a valve seat for guiding the high-pressure refrigerant to the low-pressure refrigerant outlet, a relief valve body fitted into the valve seat passage with the valve seat, and a valve opening direction of the relief valve body And a shape memory alloy spring for biasing.

  In another preferred embodiment, the relief mechanism is provided in the main valve body.

  The valve seat passage with a valve seat is preferably configured as a bypass passage that bypasses the main valve chamber and communicates the high-pressure refrigerant inlet and the low-pressure refrigerant outlet.

  The shape memory alloy spring preferably returns to its original shape and lifts the relief valve body from the valve seat when heated to a predetermined temperature (for example, 60 ° C.) or higher, which is its transformation temperature. Composed.

  The high-pressure refrigerant is preferably guided to the low-pressure refrigerant outlet through a groove or a notch formed between an inner peripheral surface of the valve-equipped passage with valve seat and the relief valve body. .

  In another preferred embodiment, an O-ring serving both as a vibration isolator and a seal is interposed between an inner peripheral surface of the valve-equipped passage with valve seat and the relief valve body, and the high-pressure refrigerant is contained in the relief valve body. It is made to guide | invade to the said low-pressure refrigerant | coolant outflow port through the conduction | electrical_connection hole provided in this.

  In another preferred aspect, the relief mechanism includes a bias spring that biases the relief valve body in a valve closing direction.

  In another preferred embodiment, a stopper for limiting the lift amount of the relief valve body from the valve seat is provided.

  The main valve body is preferably composed of an upper valve shaft and a lower valve shaft which are coaxially connected.

  In another preferred embodiment, a guide hole into which the main valve body is slidably inserted is formed above the main valve seat in the valve body, and the temperature-sensitive inlet and the flow path are formed above the guide hole. An outlet and the temperature-sensing introduction chamber are formed, and the high-pressure refrigerant inlet and outlet and a main valve chamber are formed below the guide hole.

  In another preferred embodiment, the temperature-sensitive pressure responsive element includes a diaphragm, a lid member having a reverse concave shape in cross section that defines the temperature-sensitive room in cooperation with the diaphragm, and an outer periphery of the diaphragm in cooperation with the lid member. A cylindrical lid receiving member with a hook-like portion into which the main valve body is inserted and sealed to the inner circumference of the main valve body, and to the valve body on the outer circumference of the cylindrical portion of the lid receiving member A male thread portion is provided for mounting.

  In another preferred embodiment, the main valve body and the diaphragm are coaxially arranged, and one end of the main valve body and the diaphragm are joined by projection welding.

  In another preferred embodiment, the main valve body is provided with a vertical hole having an upper surface opening, and a through-hole is formed in the diaphragm so as to communicate the temperature-sensitive room and the vertical hole. A sensitive greenhouse is constructed.

  In a preferred embodiment of the pressure control valve according to the present invention, for example, a valve-equipped passage with a valve seat for guiding high-pressure refrigerant to a low-pressure refrigerant outlet, a relief valve body fitted into the valve-equipped passage with the valve seat, and the relief valve body A relief mechanism comprising a shape memory alloy spring for urging the valve in the valve opening direction is provided in the valve main body (preferably in the main valve body), and when the temperature of the high-pressure refrigerant exceeds a predetermined temperature, Since the shape memory alloy spring senses and lifts the relief valve body in the valve opening direction, a part of the high-pressure refrigerant is relieved to the low-pressure refrigerant outlet, so that the element is generated by solar radiation or heat from the engine or the like. It is possible to reliably prevent malfunctions such as the inability to open the valve due to an increase in the internal pressure.

  In addition, the temperature-sensitive pressure responsive element is not built in the valve body, but is attached by a method such as screwing into the valve body from the outside, etc., simplifying the configuration, reducing the number of parts, reducing processing and assembly costs, etc. Can be effectively achieved.

Hereinafter, embodiments of a pressure control valve of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a pressure control valve according to the present invention. As shown in FIG. 3, the pressure control valve 1A of the illustrated first embodiment is incorporated in a vapor compression refrigeration cycle 100A basically similar to that shown in FIG. The refrigerant introduced through the internal heat exchanger 103 is regulated in accordance with the refrigerant temperature on the outlet side of the gas cooler 102 and led to the evaporator 104. In the refrigeration cycle 100A shown in FIG. 3, the same components or the same functional parts as those in the refrigeration cycle 100 shown in FIG.

  The pressure control valve 1A is provided to efficiently operate the refrigeration cycle 100A, in other words, the refrigerant on the outlet side of the gas cooler 102 so that the maximum coefficient of performance is obtained with respect to the refrigerant temperature on the outlet side of the gas cooler 102. It is provided to regulate the pressure, and includes a valve main body 10A, a main valve body 15, and a temperature-sensitive pressure responsive element 20. The main valve body 15 is coaxially connected to a stepped columnar or cylindrical upper valve rod 15A provided with a vertical hole 19 having an upper surface opening, and an upper portion of the main valve body 15 is screwed to the upper valve rod 15A. The conical surface main valve portion 17 is composed of a stepped cylindrical lower valve rod 15B provided at the lower end portion.

  The valve body 10A is formed by cutting or cutting the following parts on a bulk material cut out from an aluminum extruded bar, and in the lower part, refrigerant from the gas cooler 102 is passed through an internal heat exchanger 103. A high-pressure refrigerant inlet (joint portion) 11 that opens to the right side including an inlet passage portion 11a for introduction, a main valve chamber 14 into which refrigerant from the high-pressure refrigerant inlet 11 is introduced, and a bottom portion of the main valve chamber 14 A main valve seat 13 having a conical surface to which the main valve body 15 (the main valve portion 17) contacts and separates, and an outlet passage portion 12a for leading the refrigerant from the valve chamber 14 to the evaporator 104. A low-pressure refrigerant outlet (joint portion) 12 that opens to the left side is formed. A small notch (not shown) is formed in the main valve seat 13, and the valve opening degree of the control valve 1A is the lift from the main valve seat 13 of the main valve body 15 (the main valve portion 17). It corresponds to the amount.

  Further, a guide hole 18 is formed in the central portion of the valve body 10A so as to be slidably inserted into the lower valve rod 15B of the main valve body 15 so as to be continuous with the main valve chamber 14. That is, in the upper part of the valve body 10A, a temperature-sensitive inlet 61 opened to the left side for introducing the refrigerant from the gas cooler 102, and a right side for leading the refrigerant to the internal heat exchanger 103. A temperature-sensing outlet 62 is formed, and a temperature-sensing introduction chamber 60 is formed between the temperature-sensing inlet 61 and the outlet 62. The temperature sensing introduction chamber 60 has a convex cross section including the upper portion of the upper valve stem 15A. Further, a female thread portion 10b for attaching a temperature sensitive pressure responsive element 20 (described later) to the valve main body 10A is formed on the upper inner periphery of the valve main body 10A. An O-ring 48 is mounted between the outer peripheral surface of the lower valve stem 15B and the guide hole 18 so as to block the refrigerant from flowing between the main valve chamber 14 and the temperature sensing introduction chamber 60. ing.

  The temperature-sensitive pressure responsive element 20 includes a bottomed short cylindrical diaphragm 21, a lid member 22 having a reverse concave shape in cross section that defines a temperature-sensitive greenhouse (diaphragm chamber) 25 in cooperation with the diaphragm 21, and the lid member 22 is provided with a hook-like portion 23a in which the upper part of the upper valve stem 15A of the main valve body 15 is inserted into the inner periphery thereof while sandwiching and sealing the outer peripheral part (outer peripheral edge part and cylindrical part) of the diaphragm 21 in cooperation with A cylindrical lid receiving member 23, and the lower end portion of the lid member 22, the lid receiving member 23 (the hook-like portion 23 a), and the mating portion (clamping portion) of the diaphragm 21 is joined (welded) by all-around welding. Part Ka).

  The upper valve rod 15A of the main valve body 15 is composed of a shaft portion 15a and a bowl-shaped large diameter portion 15b provided at the upper end portion thereof, and the bowl-shaped large diameter portion 15b is formed at the upper center of the lid receiving member 23. It is inserted so as to be able to move up and down in a state where it floats in a recess 23d. An annular protrusion 16 having a trapezoidal cross section is formed on the upper surface of the bowl-shaped large-diameter portion 15b, and an annular groove is formed on the inner and outer periphery thereof. A diaphragm 21 is placed on the annular protrusion 16 on the main valve body 15 (upper valve stem 15A). ) And is coaxially joined by projection welding (welded portion Kb).

  In addition, a vertical hole 19 having an upper surface opening is provided on the upper part of the upper valve rod 15A, and a through hole 21a is formed in the center of the diaphragm 21 so as to communicate the temperature sensitive chamber 25 and the vertical hole 19 with each other. 19 constitutes one extended sensation greenhouse 25 '. In this manner, the temperature sensing capability is enhanced by extending the temperature sensing greenhouse to the temperature sensing introduction chamber 60 side.

On the other hand, in the extended sensation greenhouse 25 ′ (sensation chamber 25 + vertical hole 19), the maximum coefficient of performance is obtained with respect to the refrigerant temperature on the outlet side of the gas cooler 102 from the short capillary tube 39 fixed to the sensation chamber 25. The refrigerant pressure on the outlet side of the gas cooler 102 is adjusted (for example, when the refrigerant temperature on the outlet side is 40 ° C. and the refrigerant coefficient on the outlet side is, for example, 10 MPa, the coefficient of performance is maximized. CO ₂ is sealed at a predetermined density and an inert gas such as nitrogen gas is raised and sealed, and in this state, the end of the capillary tube 39 is sealed. It has been stopped.

  Further, on the outer periphery of the cylindrical portion of the lid receiving member 23, there is provided a male screw portion 23b that is used for attachment to the valve main body 10A and screwed into the female screw portion 10b. In the unit composed of the combined temperature-sensitive pressure responsive element 20 (diaphragm 21, lid member 22, lid receiving member 23) and main valve body 15, the male screw portion 23b is screwed into the female screw portion 10b of the valve body 10A. It is screwed in by rotating the whole and attached to the valve body 10A. In the state of being attached to the valve body 10A in this way, a temperature sensing introduction chamber 60 is formed around the main valve body 15 (upper valve stem 15A), and the temperature of the refrigerant in the temperature sensing introduction chamber 60 is expanded. It will be sensed by the greenhouse 25 '.

  A gasket 26 is interposed between the lower surface of the lid receiving member 23 and the upper surface of the valve body 10A. Although not shown, the valve body 10A is formed with a screw hole, a round hole, or the like for mounting and fixing the control valve 1A to the gas cooler 102, the internal heat exchanger 103, or the like.

  In addition to the above configuration, in the pressure control valve 1A of the present embodiment, when the temperature of the high-pressure refrigerant introduced into the temperature sensing introduction chamber 60 in the main valve body 15 (lower valve rod 15B) is equal to or higher than a predetermined temperature. A relief mechanism is provided to allow a part of the high-pressure refrigerant to escape to the low-pressure refrigerant outlet 12.

  The relief mechanism is formed below a plurality of inlets 31 that open to the temperature-sensing introduction chamber 60, a valve hole (relief valve chamber) 32 having an upper surface provided with a valve seat 35 at the bottom, and the valve hole 32. A valve seat passage 30 with a valve seat comprising an outlet 33, and a large-diameter portion 41 fitted into a valve hole 32 of the valve seat passage 30 with the valve seat and a conical surface valve portion 42 contacting and separating from the valve seat 35. A stepped columnar relief valve body 40 having a shape, and a shape memory alloy made by compression between the large diameter portion 41 and the bottom of the valve hole 32 to urge the relief valve body 40 in the valve opening direction. A spring 45 and a bias spring 46 that is compressed between the bottom surface of the upper valve stem 15A and the large-diameter portion 41 are provided to urge the relief valve element 40 in the valve closing direction.

  A plurality of vertical grooves 47 having a rectangular cross section as shown in FIG. 2A are provided on the outer periphery of the large-diameter portion 41 of the relief valve body 40, and the high-pressure refrigerant in the temperature-sensing introduction chamber 60 is: When the relief valve body 40 is opened, the inlet 31 → the vertical groove 47 (between the inner peripheral surface of the valve hole 32 and the relief valve body 40) → between the valve seat 35 and the valve portion 42 (depending on the lift amount). → The gas is led to the low-pressure refrigerant outlet 12 through the outlet 33. In addition, instead of the longitudinal groove 47, a parallel chamfered cutout 47 'as shown in FIG. 2B or the like may be formed on the outer periphery of the large diameter portion 41 of the relief valve body 40.

  Further, a stopper 43 for restricting the lift amount of the relief valve body 40 (the valve portion 42) from the valve seat 35 protrudes from the upper portion of the relief valve body 40, and the stopper 43 serves as an upper valve. When it comes into contact with the bottom surface of the rod 15A, the lift of the relief valve body 40 is stopped.

  The shape memory alloy spring 45 is made of, for example, a Ni-Ti (nickel titanium) alloy with a slight addition of Cu (copper) to adjust the temperature to be memorized. The relief valve body returns to its original shape (extends) when heated to a predetermined temperature (for example, 60 ° C.) that is a transformation temperature (transformation point) that causes a phase transformation from the martensite phase to the austenite phase. 40 is lifted (opened) from the valve seat 35.

  In the pressure control valve 1A of the present embodiment configured as described above, when the refrigerant on the outlet side of the gas cooler 102 is introduced from the temperature sensing inlet 61 into the temperature sensing introduction chamber 60, the expansion sensing greenhouse 25 ' The refrigerant temperature at the outlet side of the gas cooler 102 is sensed, and the internal pressure of the extended sensation greenhouse 25 ′ becomes a value corresponding to the refrigerant temperature at the outlet side of the gas cooler 102. Thus, the main valve body 15 is driven in the opening / closing direction, whereby the valve opening is adjusted, and the refrigerant pressure on the outlet side of the gas cooler 102 is adjusted so that the maximum coefficient of performance is obtained with respect to the refrigerant temperature on the outlet side of the gas cooler 102. It is regulated.

  Thus, in the pressure control valve 1A of the present embodiment, the valve opening degree is adjusted only by the temperature-sensitive pressure responsive element 20, so that the valve opening degree (the lift amount of the main valve body 15) is increased. 'The structure is simplified, the number of parts is reduced, and the temperature-sensitive pressure is compared with that determined by the balanced relationship between the valve opening force due to the internal and external differential pressure and the valve closing force due to the spring member. Since the responding element 20 is attached to the valve body 10A from the outside without being incorporated in the valve body, the structure is simplified, the number of parts is reduced, and the processing and assembly costs are reduced. Can be achieved.

  In addition to the above, the valve seat passage 30 with a valve seat for guiding the high-pressure refrigerant to the low-pressure refrigerant outlet 12 in the main valve body 15, the relief valve body 40 fitted in the valve seat passage 30 with the valve seat, and the relief valve body A relief mechanism including a shape memory alloy spring 45 for urging 40 in the valve opening direction, and when the temperature of the high-pressure refrigerant reaches a predetermined temperature (for example, 60 ° C.) or higher, the shape memory is stored. Since the alloy spring 45 senses and lifts the relief valve body 40 in the valve opening direction, a part of the high-pressure refrigerant is relieved to the low-pressure refrigerant outlet 12, so that the element is caused by solar radiation or heat from the engine or the like. It is possible to reliably prevent malfunctions such as the inability to open the valve due to an increase in the internal pressure.

  In the pressure control valve 1A of the first embodiment, the upstream side (the temperature sensing introduction chamber 60 side such as the inside of the valve hole 32) from the valve portion 42 (valve seat 35) of the relief valve body 40 has a high pressure Ph. Since the downstream side (low pressure refrigerant outlet 12 side) becomes the low pressure Pl, a differential pressure is generated between them (Ph−Pl> 0). Therefore, after the compressor 101 is started, the differential pressure works in a direction to close the relief valve body 40.

  FIG. 4 is a longitudinal sectional view of a second embodiment of the pressure control valve according to the present invention. The pressure control valve 1B of the illustrated second embodiment has basically the same configuration as the pressure control valve 1A of the first embodiment (part corresponding to each part of the pressure control valve 1A of the first embodiment or the same function). In the pressure control valve 1B of this embodiment, the inner peripheral surface of the valve seat passage 30 (valve hole 32) and the relief valve element 40 are omitted. The high-pressure refrigerant in the temperature-sensing introduction chamber 60 is not the vertical groove 47 but the upper horizontal hole formed in the relief valve body 40. 44a, a vertical hole 44b, and a lower horizontal hole 44c through a conduction hole (equal pressure equalization hole) that is guided to the low-pressure refrigerant outlet 12. Even under such a configuration, substantially the same as in the first embodiment. Effects can be obtained.

  FIG. 5 is a longitudinal sectional view of a third embodiment of the pressure control valve according to the present invention. The pressure control valve 1C of the third embodiment shown in the figure is basically the same as the pressure control valve 1A of the first embodiment except for the main valve body 15 and the relief mechanism (the pressure control valve of the first embodiment). The parts corresponding to the respective parts of 1A or the same function parts are denoted by the same reference numerals and their duplicate description is omitted). In the pressure control valve 1C of the present embodiment, the valve-equipped passage with valve seats (first and second) (Denoted by reference numeral 30 in the embodiment) includes a bypass passage 50 that bypasses the main valve chamber 14 and communicates the high-pressure refrigerant inlet 11 and the low-pressure refrigerant outlet 12.

  That is, in the present embodiment, the main valve body 15 is constituted by an upper valve stem 15A and a stepped solid cylindrical lower valve stem 15B ′ connected and fixed to the lower portion thereof by press-fit welding or the like, and a relief mechanism. Is a valve seat that bypasses the main valve chamber 14 and communicates the high-pressure refrigerant inlet 11 that opens to the right including the inlet passage 11a and the low-pressure refrigerant outlet 12 that opens to the left including the outlet passage 12a. A stepped columnar relief valve body having a bypass passage 50 as a valved passage with 55 and a conical surface-shaped large-diameter valve portion 42 ′ that is fitted into and inserted into the bypass passage 50 and contacts and separates from the valve seat 55. 40, a shape memory alloy spring 45 that is compressed between the upper surface of the relief valve body 40 and the upper surface (recessed portion) of the inlet passage portion 11a to urge the relief valve body 40 in the valve opening direction, and the relief In order to urge the valve body 40 in the valve closing direction, In the large-diameter relief valve chamber 53 on the upstream side of the valve seat 55 in the passage 50, more specifically, a plug for closure sealing screwed to the lower surface of the large-diameter valve portion 42 and the lower end portion of the valve body 10C. 56 and a bias spring 46 that is contracted between the bias spring 46 and the bias spring 46. A gasket 51 is interposed to securely seal between the plug 56 and the valve body 10 </ b> C, and the gasket 51 is tightened by the plug 56.

  The relief valve body 40 is formed with a conduction hole (pressure equalizing hole) 44 so as to penetrate the central portion thereof, and is used for vibration isolation between the inner peripheral surface of the bypass passage 50 and the relief valve body 40. The high-pressure refrigerant in the temperature-sensing introduction chamber 60 is inserted into the inlet passage portion 11a → the conduction hole 44 → the relief valve chamber when the relief valve body 40 is opened. 32 → Between the valve seat 55 and the large-diameter valve portion 42 ′ (according to the lift amount) → the passage through the communication passage 57 is led to the low-pressure refrigerant outlet 12.

  Even under such a configuration, substantially the same operational effects as those of the first and second embodiments can be obtained.

  In the pressure control valve 1C of the third embodiment, the upper end side (the high-pressure refrigerant inlet 11 side) and the lower end side (the relief valve chamber 53 side) of the relief valve body 40 are both at a high pressure Ph. There is no differential pressure. Therefore, the relief valve body 40 opens and closes depending on only the spring load (temperature only) of the shape memory alloy spring 45.

  In the third embodiment, although it is impossible to adjust the set load of the bias spring 46, it can be made adjustable. That is, as shown in FIG. 6, the lower portion of the valve body 10 </ b> C is extended downward (the relief valve chamber 53 is extended downward), and a female screw portion 54 is provided in the relief valve chamber 53, and the female screw portion 54 is adjusted. The screw 52 is screwed to receive the lower end of the bias spring 46. By doing so, it is possible to arbitrarily change the set load of the bias spring 46 by adjusting the screwing amount of the adjusting screw 52.

  FIG. 7 is a longitudinal sectional view of a fourth embodiment of the pressure control valve according to the present invention. The pressure control valve 1D of the fourth embodiment shown in the figure has basically the same configuration as the pressure control valve 1C of the third embodiment (part corresponding to each part of the pressure control valve 1C of the third embodiment or the same function). In the pressure control valve 1D of the present embodiment, between the inner peripheral surface of the bypass passage 50 and the relief valve body 40 in the third embodiment, the same reference numerals are assigned to the portions, and the duplicate description thereof is omitted. The distributed O-ring 58 is removed, and a clearance S is formed between the inner peripheral surface of the bypass passage 50 and the outer peripheral surface of the relief valve body 40, and the high-pressure refrigerant is always bleed through the clearance S. Even under such a configuration, substantially the same operational effects as those of the first to third embodiments can be obtained.

The longitudinal cross-sectional view which shows 1st Embodiment of the pressure control valve which concerns on this invention. XX arrow sectional drawing of FIG. The figure which shows an example of the vapor compression refrigeration cycle in which the pressure control valve of 1st Embodiment was integrated. The longitudinal cross-sectional view which shows 2nd Embodiment of the pressure control valve which concerns on this invention. The longitudinal cross-sectional view which shows 3rd Embodiment of the pressure control valve which concerns on this invention. The longitudinal cross-sectional view which shows the modification of the pressure control valve of 3rd Embodiment shown by FIG. The longitudinal cross-sectional view which shows 4th Embodiment of the pressure control valve which concerns on this invention. The figure which shows an example of the vapor compression refrigeration cycle in which the conventional pressure control valve was incorporated.

Explanation of symbols

1A, 1B, 1C, 1D ... Pressure control valves 10A, 10B, 10C, 10D ... Valve body 11 ... High pressure refrigerant inlet 12 ... Low pressure refrigerant outlet 13 ... Main valve seat 14 ... Main valve chamber 15 ... Main valve body 15A ... Upper valve stem 15B ... Lower valve stem 17 ... Main valve portion 19 ... Vertical hole 20 ... Temperature sensitive pressure responsive element 21 ... Diaphragm 22 ... Lid member 23 ... Lid receiving member 25 ... Sensitive greenhouse 25 '... Expanded sensation greenhouse 30 ... Valve seat Passage 32 ... Valve hole (relief valve chamber)
35 ... Valve seat 40 ... Relief valve element 42 ... Valve part 43 ... Stopper 45 ... Shape memory alloy spring 46 ... Bias spring 50 ... Bypass passage 51 ... Gasket 55 ... Valve seat 61 ... Temperature sensing inlet 62 ... For temperature sensing Outlet 100A ... Vapor compression refrigeration cycle 101 ... Compressor 102 ... Gas cooler 103 ... Internal heat exchanger 104 ... Evaporator

Claims (14)

A compressor for circulating CO ₂ as a refrigerant, a gas cooler for cooling the high-pressure refrigerant compressed by the compressor, an evaporator into which the refrigerant from the gas cooler is pressure-adjusted and introduced, An internal heat exchanger that exchanges heat between the low-pressure refrigerant on the outlet side and the high-pressure refrigerant on the outlet side of the gas cooler, and is introduced into the vapor compression refrigeration cycle from the gas cooler via the internal heat exchanger. A main valve chamber provided with a main valve body and a main valve seat for contacting and separating the main valve body for adjusting the pressure of the high-pressure refrigerant according to the refrigerant temperature on the outlet side of the gas cooler and leading it to the evaporator A pressure control valve having
A temperature-sensitive inlet for introducing the high-pressure refrigerant from the gas cooler, a temperature-sensitive outlet for leading it to the internal heat exchanger, and provided between the temperature-sensitive inlet and the outlet. The temperature-sensing introduction chamber, the high-pressure refrigerant inlet for introducing the high-pressure refrigerant from the internal heat exchanger into the main valve chamber, and the refrigerant adjusted to a low pressure by the main valve body are led to the evaporator. A valve body having a low-pressure refrigerant outlet, and a temperature-sensing greenhouse for sensing the temperature of the high-pressure refrigerant introduced into the temperature-sensing introduction chamber, and the main valve body in response to a change in the internal pressure of the temperature-sensing greenhouse A temperature-sensitive pressure responsive element that drives in the opening and closing direction,
The pressure control valve according to claim 1, wherein a relief mechanism is provided in the valve body for allowing a part of the high-pressure refrigerant to escape to the low-pressure refrigerant outlet when the temperature of the high-pressure refrigerant is equal to or higher than a predetermined temperature.   The relief mechanism includes a valved passage with a valve seat for guiding the high-pressure refrigerant to the outlet of the low-pressure refrigerant, a relief valve body fitted into the valved passage with the valve seat, and urges the relief valve body in a valve opening direction. The pressure control valve according to claim 1, further comprising: a shape memory alloy spring.   The pressure control valve according to claim 2, wherein the relief mechanism is provided in the main valve body.   3. The pressure according to claim 2, wherein the valve-equipped passage with the valve seat is configured by a bypass passage that bypasses the main valve chamber and communicates the high-pressure refrigerant inlet and the low-pressure refrigerant outlet. Control valve.   The shape memory alloy spring is configured to return to its original shape and lift the relief valve body from the valve seat when heated to a predetermined temperature that is its transformation temperature. Item 5. The pressure control valve according to any one of Items 2 to 4.   The high-pressure refrigerant is guided to the low-pressure refrigerant outlet through a groove or notch formed between an inner peripheral surface of the valve-equipped passage with the valve seat and the relief valve body. 6. The pressure control valve according to claim 2, wherein the pressure control valve is characterized in that:   An O-ring serving both as a vibration isolator and a seal is interposed between an inner peripheral surface of the valve seat passage with the valve seat and the relief valve body, and the high-pressure refrigerant is a conduction hole provided in the relief valve body. The pressure control valve according to any one of claims 2 to 5, wherein the pressure control valve is guided to the low-pressure refrigerant outlet through the outlet.   The pressure control valve according to claim 2, wherein the relief mechanism includes a bias spring that biases the relief valve body in a valve closing direction.   The pressure control valve according to any one of claims 2 to 8, wherein a stopper for limiting a lift amount of the relief valve body from the valve seat is provided.   2. The pressure control valve according to claim 1, wherein the main valve body includes an upper valve rod and a lower valve rod that are coaxially connected to each other.   A guide hole into which the main valve body is slidably inserted is formed above the main valve seat in the valve body, and the temperature-sensitive inlet and outlet and the temperature-sensitive inlet are above the guide hole. The pressure control valve according to claim 1, wherein an introduction chamber is formed, and the high-pressure refrigerant inlet and outlet and a main valve chamber are formed below the guide hole.   The temperature-sensitive pressure-responsive element includes a diaphragm, a lid member having an inverted concave cross-section that cooperates with the diaphragm to define the temperature-sensing greenhouse, and sandwiches and seals the outer peripheral portion of the diaphragm in cooperation with the lid member. In addition, the main valve body is provided with a cylindrical lid receiving member with a hook-like portion inserted into the inner periphery thereof, and is provided for attachment to the valve body on the outer periphery of the cylindrical portion of the lid receiving member. The pressure control valve according to claim 1, wherein a male screw portion is provided.   The pressure control valve according to claim 12, wherein the main valve body and the diaphragm are coaxially arranged, and one end portion of the main valve body and the diaphragm are joined by projection welding.   The main valve body is provided with a vertical hole having an upper surface opening, and a through-hole is formed in the diaphragm so as to communicate the temperature-sensitive room with the vertical hole. The temperature-sensitive room and the vertical hole constitute one extended temperature-sensitive room. The pressure control valve according to claim 12 or 13, wherein the pressure control valve is provided.

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