Evaporation pressure regulating valve

Abstract

To provide an evaporation pressure regulation valve capable of improving refrigeration cycle efficiency regardless of an operation condition.SOLUTION: An evaporation pressure regulation valve 19 for regulating a refrigerant evaporation pressure in an indoor evaporator 18 to be equal to or higher than a preset reference evaporation pressure is arranged between the indoor evaporator 18 and a compressor 11 in a refrigeration cycle device 10. The evaporation pressure regulation valve 19 is driven by a driving mechanism 52 which is an electric actuator. The evaporation pressure regulation valve 19 has a flow characteristic that an increase degree of a refrigerant flow rate with respect to an opening is larger as the opening becomes larger.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an evaporation pressure regulating valve used in a refrigeration cycle.

Background Art

[0002] Conventionally, in a vapor compression refrigeration cycle, an evaporation pressure regulating valve is known which is arranged between an evaporator and a compressor and adjusts the refrigerant evaporation pressure in the evaporator to be equal to or higher than a predetermined reference evaporation pressure in order to suppress frosting in the evaporator.

[0003] For example, Patent Document 1 discloses a mechanical evaporation pressure regulating valve that increases the valve opening degree as the pressure of the refrigerant on the outlet side of the evaporator increases. In the mechanical evaporation pressure regulating valve, the valve opening degree is controlled by the displacement of the valve body due to the differential pressure between the refrigerant pressure on the evaporator side and the pressure of the reference gas.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the refrigeration cycle of a vehicle air conditioner, in order to suppress the occurrence of fogging on the front glass, the refrigerant may flow through the evaporator at a large flow rate. At this time, the pressure loss of the refrigerant in the evaporator increases, and the pressure of the refrigerant on the outlet side of the evaporator decreases. As a result, the differential pressure between the refrigerant pressure on the evaporator side and the pressure of the reference gas in the evaporation pressure regulating valve decreases, and the valve opening degree may decrease. As a result, the refrigerant flow rate flowing into the evaporator decreases, the fin temperature of the evaporator cannot be sufficiently lowered, and the performance of the refrigeration cycle may deteriorate.

[0006] On the one hand, during cooling operation, in the low-flow region where the refrigerant flow rate is low, it is required to finely adjust the refrigerant flow rate. However, in the above-described conventional mechanical evaporative pressure regulating valve, in the low-flow region, since the degree of increase in the refrigerant flow rate with respect to the opening is large, it may be difficult to control the refrigerant flow rate. As a result, the performance of the refrigeration cycle may deteriorate during cooling operation.

[0007] In view of the above points, an object of the present invention is to provide an evaporative pressure regulating valve that can improve the performance of a refrigeration cycle regardless of operating conditions.

Means for Solving the Problems

[0008] In order to achieve the above object, the evaporative pressure regulating valve according to claim 1 is disposed between an evaporator (16, 18) and a compressor (11) in a refrigeration cycle (10), and adjusts the refrigerant evaporation pressure in the evaporator to be equal to or higher than a predetermined reference evaporation pressure. In the evaporative pressure regulating valve, Driven by an electric actuator (52), The degree of increase in the refrigerant flow rate with respect to the opening is greater when the opening is larger. く, a body part (51, 61, 71, 81, 91, 101) having an inlet part (51g, 61a, 71a, 91b, 102) for allowing the refrigerant flowing out from the evaporator to flow in, a refrigerant flow path (51a, 610, 710, 810, 910, 1010) for allowing the refrigerant flowing in from the inlet part to flow through, and an outlet part (51h, 61b, 71b, 91c, 103) for allowing the refrigerant flowing through the refrigerant flow path to flow out to the suction port side of the compressor, a valve body (55, 63, 73, 82, 92, 104) for adjusting the throttle opening degree of the refrigerant flow path, and controls the throttle opening degree of the refrigerant flow path based on the pressure reduction amount in a pressure reduction part (15b) that reduces the pressure of the refrigerant discharged from the compressor.

[0009] According to this, by driving with the electric actuator (52), the opening of the evaporative pressure regulating valve can be increased even when the refrigerant flow rate is large because the pressure of the refrigerant on the outlet side of the evaporator (18) does not depend on the opening. Therefore, during the dehumidification operation, the fin temperature of the evaporator (18) can be sufficiently lowered, so that the performance of the refrigeration cycle can be improved.

[0010] Also, since the degree of increase in the refrigerant flow rate with respect to the opening is greater when the opening is larger, when the refrigerant flow rate is small, the degree of increase in the refrigerant flow rate with respect to the opening can be reduced. As a result, during the cooling operation, the refrigerant flow rate can be finely adjusted, so that the performance of the refrigeration cycle can be improved.

[0011] Incidentally, the reference numerals in parentheses for each means described in this column and the claims indicate the correspondence with the specific means described in the embodiments described later.

Brief Description of the Drawings

[0012]

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Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are identical or equivalent to each other are denoted by the same reference numerals in the drawings.

[0014] (First Embodiment) The evaporation pressure regulating valve 19 according to the first embodiment is used as one of the component devices in the refrigeration cycle device 10 of the vehicle air conditioner 1. The vehicle air conditioner 1 is mounted on a hybrid vehicle that obtains driving force for vehicle running from an internal combustion engine and a driving motor for running. And the refrigeration cycle device 10 functions to cool or heat the air blown into the vehicle interior, which is the air conditioning target space, in the vehicle air conditioner 1.

[0015] As shown in FIG. 1, the evaporation pressure regulating valve 19 is disposed between the indoor evaporator 18 and the compressor 11 in the refrigeration cycle device 10, and suppresses frosting in the indoor evaporator 18.

[0016] First, the configuration of the vehicle air conditioner 1 and the refrigeration cycle device 10 including the evaporation pressure regulating valve 19 will be described with reference to FIG. 1. The refrigeration cycle device 10 according to the first embodiment is configured to be able to switch between a refrigerant circuit in the heating mode, a refrigerant circuit in the dehumidifying heating mode, and a refrigerant circuit in the cooling mode.

[0017] Here, in the vehicle air conditioner 1, the heating mode is an operation mode in which the blown air is heated and blown into the vehicle interior. The dehumidifying heating mode is an operation mode in which the cooled and dehumidified blown air is reheated and blown into the vehicle interior. Also, the cooling mode is an operation mode in which the blown air is cooled and blown into the vehicle interior.

[0018] In FIG. 1, the flow of the refrigerant in the refrigerant circuit in the heating mode is indicated by a solid black arrow, the flow of the refrigerant in the refrigerant circuit in the dehumidifying heating mode is indicated by an arrow with diagonal hatching, and the flow of the refrigerant in the refrigerant circuit in the cooling mode is indicated by a white arrow.

[0019] In the refrigeration cycle device 10, an HFC refrigerant (specifically, R134a) is adopted as the refrigerant, and a vapor compression subcritical refrigeration cycle is configured in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. Of course, an HFO refrigerant (for example, R1234yf) or a natural refrigerant (for example, R744) may be adopted as the refrigerant. Furthermore, refrigeration machine oil for lubricating the compressor 11 is mixed in the refrigerant, and a part of the refrigeration machine oil circulates in the cycle together with the refrigerant.

[0020] As shown in FIG. 1, the refrigeration cycle device 10 includes a compressor 11, a first expansion valve 15a, a second expansion valve 15b, an outdoor heat exchanger 16, a check valve 17, an indoor evaporator 18, an evaporation pressure regulating valve 19, an accumulator 20, a first on-off valve 21, and a second on-off valve 22.

[0021] The compressor 11 sucks and compresses the refrigerant in the refrigeration cycle device 10 and discharges it, and is arranged in the vehicle bonnet. The compressor 11 is configured as an electric compressor that drives a fixed displacement type compression mechanism with a fixed discharge capacity by an electric motor.

[0022] As the compression mechanism of the compressor 11, various compression mechanisms such as a scroll type compression mechanism and a vane type compression mechanism can be adopted. Also, the operation (that is, the rotation speed) of the electric motor constituting the compressor 11 is controlled by a control signal output from the air conditioning control device 100. As the electric motor, either an AC motor or a DC motor may be adopted.

[0023] The refrigerant inlet side of the indoor condenser 12 is connected to the discharge port of the compressor 11. The indoor condenser 12 functions as a heating heat exchanger in the heating mode and the dehumidifying heating mode. That is, in the heating mode and the dehumidifying heating mode, the indoor condenser 12 exchanges heat between the high-temperature and high-pressure discharged refrigerant discharged from the compressor 11 and the blown air that has passed through the indoor evaporator 18 described later to heat the blown air. The indoor condenser 12 is arranged in the casing 31 of the indoor air conditioning unit 30 described later.

[0024] One inlet / outlet side of the first three-way joint 13a is connected to the refrigerant outlet of the indoor condenser 12. A three-way joint such as the first three-way joint 13a functions as a branch or a confluence in the refrigeration cycle device 10.

[0025] For example, in the first three-way joint 13a in the dehumidifying heating mode, one of the three inlets / outlets is used as an inlet, and the remaining two are used as outlets. Therefore, the first three-way joint 13a in the dehumidifying heating mode functions as a branch that branches the flow of the refrigerant flowing in from one inlet and discharges it from two outlets. These three-way joints may be formed by joining a plurality of pipes, or may be formed by providing a plurality of refrigerant passages in a metal block or a resin block.

[0026] Furthermore, as will be described later, the refrigeration cycle device 10 includes second to fourth three-way joints 13b to 13d. The basic configuration of the second to fourth three-way joints 13b to 13d is the same as that of the first three-way joint 13a. For example, in the fourth three-way joint 13d in the dehumidifying heating mode, two of the three inlets / outlets are used as inlets, and the remaining one is used as an outlet. Therefore, the fourth three-way joint 13d in the dehumidifying heating mode functions as a confluence that combines the refrigerants flowing in from two inlets and discharges them from one outlet.

[0027] And a first refrigerant passage 14a is connected to another inlet / outlet of the first three-way joint 13a. The first refrigerant passage 14a guides the refrigerant flowing out from the indoor condenser 12 to the refrigerant inlet side of the outdoor heat exchanger 16.

[0028] Also, a second refrigerant passage 14b is connected to still another inlet / outlet of the first three-way joint 13a. The second refrigerant passage 14b guides the refrigerant flowing out from the indoor condenser 12 to the inlet side of the second expansion valve 15b disposed in the third refrigerant passage 14c (specifically, one inlet / outlet of the third three-way joint 13c).

[0029] A first expansion valve 15a is disposed in the first refrigerant passage 14a. The first expansion valve 15a reduces the pressure of the refrigerant flowing out from the indoor condenser 12 during the heating mode and the dehumidifying heating mode. The first expansion valve 15a functions as a decompression unit (i.e., a decompression device). The first expansion valve 15a is a variable throttle mechanism having a valve body configured to be able to change the throttle opening degree and an electric actuator including a stepping motor that changes the throttle opening degree of the valve body.

[0030] Furthermore, the first expansion valve 15a is configured as a variable throttle mechanism with a full - open function that functions as a mere refrigerant passage with almost no refrigerant pressure - reducing action by fully opening the throttle opening degree. The operation of the first expansion valve 15a is controlled by a control signal (i.e., a control pulse) output from the air - conditioning control device 100.

[0031] On the outlet side of the first expansion valve 15a, the refrigerant inlet side of the outdoor heat exchanger 16 is connected, and it is disposed on the front side of the vehicle inside the vehicle bonnet. The outdoor heat exchanger 16 exchanges heat between the refrigerant flowing out from the first expansion valve 15a and the outside air (i.e., the outside air) blown from a blower fan (not shown). The blower fan is an electric blower whose rotation speed (i.e., the blowing capacity) is controlled by a control voltage output from the air - conditioning control device 100.

[0032] Specifically, the outdoor heat exchanger 16 functions as a heat absorber that absorbs heat from the outside air during the heating mode. During the cooling mode and the dehumidifying heating mode, the outdoor heat exchanger 16 functions as a radiator that radiates heat to the outside air.

[0033] One inlet - outlet of the second three - way joint 13b is connected to the refrigerant outlet side of the outdoor heat exchanger 16. Another inlet - outlet of the second three - way joint 13b is connected to the third refrigerant passage 14c. The third refrigerant passage 14c guides the refrigerant flowing out from the outdoor heat exchanger 16 to the refrigerant inlet side of the indoor evaporator 18.

[0034] Further, a fourth refrigerant passage 14d is connected to yet another inlet / outlet of the second three-way joint 13b. The fourth refrigerant passage 14d guides the refrigerant flowing out from the outdoor heat exchanger 16 to the inlet side of an accumulator 20 to be described later (specifically, one inlet / outlet of the fourth three-way joint 13d).

[0035] A check valve 17, a third three-way joint 13c, and a second expansion valve 15b are arranged in this order with respect to the refrigerant flow in the third refrigerant passage 14c. The check valve 17 allows only the refrigerant to flow from the second three-way joint 13b side to the indoor evaporator 18 side. The second refrigerant passage 14b described above is connected to the third three-way joint 13c.

[0036] The second expansion valve 15b reduces the pressure of the refrigerant flowing out from the outdoor heat exchanger 16 and flowing into the indoor evaporator 18. That is, the second expansion valve 15b functions as a pressure reducing section (i.e., a pressure reducing device). The basic configuration of the second expansion valve 15b is the same as that of the first expansion valve 15a. Further, the second expansion valve 15b is composed of a variable throttle mechanism with a fully closed function that closes this refrigerant passage when the throttle opening is fully closed.

[0037] Therefore, in the refrigeration cycle device 10 according to the first embodiment, the refrigerant circuit can be switched by fully closing the second expansion valve 15b to close the third refrigerant passage 14c. In other words, the second expansion valve 15b functions as a refrigerant pressure reducing device and also functions as a refrigerant circuit switching device that switches the refrigerant circuit of the refrigerant circulating in the cycle.

[0038] The indoor evaporator 18 functions as a cooling heat exchanger in the cooling mode and the dehumidifying heating mode. That is, in the cooling mode and the dehumidifying heating mode, the indoor evaporator 18 exchanges heat between the refrigerant flowing out from the second expansion valve 15b and the supply air before passing through the indoor condenser 12, and functions as an evaporator in the present invention. In the indoor evaporator 18, the refrigerant depressurized by the second expansion valve 15b is evaporated to exert an endothermic effect, thereby cooling the supply air. The indoor evaporator 18 is arranged on the upstream side of the supply air flow of the indoor condenser 12 in the casing 31 of the indoor air conditioning unit 30.

[0039] The inlet side of the expansion pressure regulating valve 19 is connected to the refrigerant outlet of the indoor evaporator 18. The expansion pressure regulating valve 19 functions to adjust the refrigerant evaporation pressure (i.e., the low-pressure side refrigerant pressure) in the indoor evaporator 18 to be equal to or higher than the frost suppression pressure in order to suppress frosting (frost) in the indoor evaporator 18. In other words, the expansion pressure regulating valve 19 adjusts the refrigerant evaporation temperature in the indoor evaporator 18 to be equal to or higher than a predetermined frost suppression temperature.

[0040] The expansion pressure regulating valve 19 is an electric valve configured to have a valve body whose throttle opening can be changed and an electric actuator that changes the throttle opening of this valve body. The operation of the expansion pressure regulating valve 19 is controlled by a control signal (i.e., a control pulse) output from the air conditioning control device 100. The specific configuration of the expansion pressure regulating valve 19 will be described in detail later with reference to the drawings.

[0041] A fourth three-way joint 13d is connected to the outlet side of the expansion pressure regulating valve 19. Also, as described above, a fourth refrigerant passage 14d is connected to the other inlet / outlet in the fourth three-way joint 13d. And the inlet side of the accumulator 20 is connected to yet another inlet / outlet of the fourth three-way joint 13d.

[0042] The accumulator 20 is a gas-liquid separator that separates the gas and liquid of the refrigerant flowing into it and stores the excess refrigerant in the cycle. The suction inlet side of the compressor 11 is connected to the gas-phase refrigerant outlet of the accumulator 20. Therefore, the accumulator 20 suppresses the suction of liquid-phase refrigerant into the compressor 11 and prevents liquid compression in the compressor 11.

[0043] Also, a first on-off valve 21 is arranged in the fourth refrigerant passage 14d that connects the second three-way joint 13b and the fourth three-way joint 13d. The first on-off valve 21 is constituted by an electromagnetic valve. And the first on-off valve 21 functions as a refrigerant circuit switching device that switches the refrigerant circuit by opening and closing the fourth refrigerant passage 14d. The operation of the first on-off valve 21 is controlled by a control signal output from the air conditioning control device 100.

[0044] Similarly, a second refrigerant passage 14b that connects the first three-way joint 13a and the third three-way joint 13c is provided with a second on-off valve 22. The second on-off valve 22 is constituted by a solenoid valve, similarly to the first on-off valve 21. The second on-off valve 22 functions as a refrigerant circuit switching device that switches the refrigerant circuit by opening and closing the second refrigerant passage 14b.

[0045] Next, the in-vehicle air conditioner unit 30 that constitutes the in-vehicle air conditioner 1 together with the refrigeration cycle device 10 will be described. The in-vehicle air conditioner unit 30 is for blowing out the blown air whose temperature has been adjusted by the refrigeration cycle device 10 into the vehicle interior. This in-vehicle air conditioner unit 30 is disposed inside the instrument panel (i.e., the instrument panel) at the foremost part of the vehicle interior.

[0046] The in-vehicle air conditioner unit 30 is configured by housing a blower 32, an in-vehicle evaporator 18, an in-vehicle condenser 12, etc. inside a casing 31 that forms its outer shell. The casing 31 forms an air passage for the blown air blown into the vehicle interior. The casing 31 is made of a resin (for example, polypropylene) having a certain degree of elasticity and excellent strength, and is molded therefrom.

[0047] An inside / outside air switching device 33 is disposed on the most upstream side of the blown air flow inside the casing 31. The inside / outside air switching device 33 switches and introduces inside air (i.e., vehicle interior air) and outside air (i.e., vehicle exterior air) into the casing 31.

[0048] Specifically, the inside / outside air switching device 33 continuously adjusts the opening areas of the inside air inlet for introducing inside air and the outside air inlet for introducing outside air into the casing 31 by means of an inside / outside air switching door, and can continuously change the air volume ratio between the inside air volume and the outside air volume. The inside / outside air switching door is driven by an electric actuator for the inside / outside air switching door. The operation of this electric actuator is controlled by a control signal output from the air conditioning control device 100.

[0049] And, on the downstream side of the air flow of the inside / outside air switching device 33, a blower (i.e., a fan) 32 is arranged. This blower 32 blows the air inhaled through the inside / outside air switching device 33 toward the vehicle interior. The blower 32 is an electric blower that drives a centrifugal multi-blade fan (i.e., a sirocco fan) with an electric motor. The rotational speed (i.e., the air volume) of the centrifugal multi-blade fan in the blower 32 is controlled by the control voltage output from the air conditioning control device 100.

[0050] On the downstream side of the air flow of the blower 32, an indoor evaporator 18 and an indoor condenser 12 are arranged in this order with respect to the air flow. In other words, the indoor evaporator 18 is arranged on the upstream side of the air flow with respect to the indoor condenser 12.

[0051] Also, a cold air bypass passage 35 is formed in the casing 31. The cold air bypass passage 35 is a passage for flowing the air that has passed through the indoor evaporator 18 around the indoor condenser 12 and to the downstream side.

[0052] An air mix door 34 is arranged on the downstream side of the air flow of the indoor evaporator 18 and on the upstream side of the air flow of the indoor condenser 12. The air mix door 34 is used when adjusting the air volume ratio of the air that has passed through the indoor evaporator 18 and passes through the indoor condenser 12. Therefore, the vehicle air conditioning device 1 can minimize the heat exchange amount in the indoor condenser 12 by setting the cold air bypass passage 35 to the fully open position and closing the air flow path toward the indoor condenser 12 with the air mix door 34.

[0053] Also, a mixing space is provided on the downstream side of the air flow of the indoor condenser 12. In the mixing space, the air that has been heated by the indoor condenser 12 and the air that has passed through the cold air bypass passage 35 and has not been heated by the indoor condenser 12 are mixed. Further, a plurality of opening holes are arranged at the most downstream part of the air flow of the casing 31. The air (i.e., the conditioned air) mixed in the mixing space is blown into the vehicle interior, which is the air conditioning target space, through these opening holes.

[0054] Specifically, as these opening holes, there are provided a face opening hole, a foot opening hole, and a defroster opening hole (none of which are shown in the drawings). The face opening hole is an opening hole for blowing out conditioned air toward the upper body of the occupant in the vehicle interior. The foot opening hole is an opening hole for blowing out conditioned air toward the feet of the occupant. The defroster opening hole is an opening hole for blowing out conditioned air toward the inner surface of the front windshield of the vehicle.

[0055] Furthermore, the downstream sides of the air flow of the face opening hole, the foot opening hole, and the defroster opening hole are respectively connected to a face air outlet, a foot air outlet, and a defroster air outlet (none of which are shown in the drawings) provided in the vehicle interior via ducts that form air passages. Therefore, by adjusting the air volume ratio between the air volume passing through the in-vehicle condenser 12 and the air volume passing through the cold air bypass passage 35 by the air mix door 34, the temperature of the conditioned air mixed in the mixing space is adjusted, and the temperature of the conditioned air blown into the vehicle interior from each air outlet is adjusted.

[0056] That is, the air mix door 34 functions as a temperature adjustment unit that adjusts the temperature of the conditioned air blown into the vehicle interior. The air mix door 34 is driven by an electric actuator for driving the air mix door. The operation of this electric actuator is controlled by a control signal output from the air conditioning control device 100.

[0057] Also, on the upstream sides of the air flow of the face opening hole, the foot opening hole, and the defroster opening hole, there are respectively arranged a face door for adjusting the opening area of the face opening hole, a foot door for adjusting the opening area of the foot opening hole, and a defroster door for adjusting the opening area of the defroster opening hole (none of which are shown in the drawings).

[0058] These face doors, foot doors, and defroster doors constitute an air outlet mode switching door that switches the air outlet mode. The face door, foot door, and defroster door are each connected to an electric actuator for driving the air outlet mode door via a link mechanism or the like, and are rotated in conjunction with each other. The operation of this electric actuator is also controlled by a control signal output from the air conditioning control device 100.

[0059] Specifically, the air outlet modes switched by the air outlet mode switching door include a face mode, a bi-level mode, a foot mode, etc.

[0060] The face mode is an air outlet mode in which the face air outlet is fully opened and air is blown from the face air outlet toward the upper body of the vehicle interior occupants. The bi-level mode is an air outlet mode in which both the face air outlet and the foot air outlet are opened and air is blown toward the upper body and the feet of the vehicle interior occupants. The foot mode is an air outlet mode in which the foot air outlet is fully opened and blown air is blown from the foot air outlet toward the feet of the vehicle interior occupants.

[0061] Furthermore, by manually operating the air outlet mode switching switch provided on the operation panel by the occupant, a defroster mode can also be set. The defroster mode is an air outlet mode in which the defroster air outlet is fully opened and air is blown from the defroster air outlet toward the inner surface of the vehicle front window glass.

[0062] The air conditioning control device 100 is composed of a well-known microcomputer including a CPU, ROM, RAM, etc. and its peripheral circuits, performs various calculations and processes based on the air conditioning control program stored in its ROM, and controls the operations of various controlled devices connected to the output side.

[0063] And as described above, the vehicle air conditioner 1 can switch its operation mode among cooling operation, heating operation, and dehumidifying heating operation. The specific operations and controls for each of these operation modes are already known content and are described in, for example, Japanese Patent Application Laid-Open No. 2012-225637 and the like. Therefore, the explanation of these points is omitted.

[0064] Next, the specific configuration of the evaporation pressure regulating valve 19 disposed in the vehicle air conditioner 1 and the refrigeration cycle device 10 will be described in detail with reference to the drawings.

[0065] As described above, the evaporation pressure regulating valve 19 according to the first embodiment is disposed between the indoor evaporator 18 and the compressor 11 in the refrigeration cycle device 10. The evaporation pressure regulating valve 19 functions to adjust the refrigerant evaporation pressure P1 in the indoor evaporator 18 to be equal to or higher than a predetermined reference evaporation pressure (i.e., the frost formation suppression pressure APe).

[0066] As shown in FIG. 2, the evaporation pressure regulating valve 19 has a body portion 51 made of an aluminum alloy or the like. The evaporation pressure regulating valve 19 is configured by slidably accommodating a valve body 55 in a valve chamber 51a on a refrigerant flow path formed inside the body portion 51.

[0067] Specifically, the evaporation pressure regulating valve 19 includes a body portion 51, a drive mechanism 52, an outer guide portion 53, an inner guide portion 54, a valve body 55, and a coil spring 56.

[0068] The body portion 51 is formed with a hollow cylindrical valve chamber 51a. A hollow cylindrical inflow path 51b is formed in the lower portion of the peripheral wall surface of the valve chamber 51a. A hollow cylindrical outflow path 51c is concentrically formed at the center of the lower surface of the valve chamber 51a. The valve chamber 51a, the inflow path 51b, and the outflow path 51c constitute a continuous L-shaped fluid passage 51d.

[0069] On the lower surface of the valve chamber 51a, that is, at the edge of the upper end opening of the outflow passage 51c, a valve seat 51e is formed concentrically. The upper surface of the valve seat 51e is composed of a plane orthogonal to the axis of the valve chamber 51a.

[0070] In the central part of the upper surface of the valve chamber 51a, a hollow cylindrical shaft passage 51j is formed. The output shaft 52a and the power transmission part 52b, which will be described later, are inserted into the shaft passage 51j. On the inner peripheral surface of the lower side of the shaft passage 51j, an internal thread part 51f is formed.

[0071] Also, an inlet part 51g and an outlet part 51h are formed in the body part 51. The inlet part 51g allows the refrigerant flowing out from the indoor evaporator 18 through the shaft passage 51j to flow in. The outlet part 51h allows the refrigerant that has flowed through the valve chamber 51a to flow out to the suction port side of the compressor 11. The inlet part 51g is connected to the inlet side of the inflow passage 51b. The outlet part 51h is connected to the outlet side of the outflow passage 51c.

[0072] The refrigerant flowing in from the inlet part 51g flows into the valve chamber 51a through the inflow passage 51b, and then flows out from the outlet part 51h through the outflow passage 51c. Therefore, the valve chamber 51a corresponds to a refrigerant flow path that allows the refrigerant flowing in from the inlet part 51g to flow through.

[0073] In the refrigerant flow path in the body part 51, the angle formed by the flow of the refrigerant from the inlet part 51g toward the valve body 55 and the flow of the refrigerant from the valve body 55 toward the outlet part 51h is 90°. In other words, the angle formed by the flow of the refrigerant flowing through the inflow passage 51b and the flow of the refrigerant flowing through the outflow passage 51c is 90°.

[0074] The drive mechanism 52 is an electric actuator that displaces the valve body 55. In this embodiment, a stepping motor is adopted as the drive mechanism 52.

[0075] The drive mechanism 52 is installed on the upper part of the body portion 51. The drive mechanism 52 is provided with an output shaft 52a that protrudes from the lower surface of the motor body and can rotate forward and backward. At the lower end of the output shaft 52a, a power transmission portion 52b that transmits the power of the drive mechanism 52 via the output shaft 52a is connected. The power transmission portion 52b is formed in a substantially cylindrical shape that extends concentrically with the output shaft 52a. The output shaft 52a and the power transmission portion 52b are concentrically arranged within the shaft passage 51j of the body portion 51.

[0076] The outer guide portion 53 is formed in a bottomed cylindrical shape having a cylindrical wall portion 53a and a bottom wall portion 53b that closes the lower end opening of the wall portion 53a. The outer guide portion 53 is arranged within the valve chamber 51a of the body portion 51. The wall portion 53a is arranged concentrically with the valve chamber 51a. The upper end portion of the wall portion 53a is fixed to the upper wall surface of the valve chamber 51a. A through hole 53c through which a valve-side cylindrical portion 55b of a valve body 55 described later is inserted is formed at the center of the bottom wall portion 53b.

[0077] An inner guide portion 54 is arranged inside the outer guide portion 53. The inner guide portion 54 is arranged within the valve chamber 51a of the body portion 51 so as to be movable in the vertical direction (i.e., the axial direction) while being prevented from rotating around the axis by a rotation prevention portion (not shown).

[0078] The inner guide portion 54 is formed in a substantially T-shaped cross section when viewed from a direction perpendicular to the axial direction of the valve chamber 51a. The inner guide portion 54 has a guide-side disc portion 54a and a guide-side cylindrical portion 54b. Both the guide-side disc portion 54a and the guide-side cylindrical portion 54b are formed concentrically with the valve chamber 51a. The guide-side disc portion 54a is arranged on the upper surface of the guide-side cylindrical portion 54b. The diameter of the guide-side cylindrical portion 54b is smaller than the diameter of the guide-side disc portion 54a.

[0079] The guide-side disc portion 54a of the inner guide portion 54 is connected to the power transmission portion 52b via a steel ball 54c. Also, a valve body 55 is connected to the lower end surface of the guide-side cylindrical portion 54b of the inner guide portion 54.

[0080] Here, a male screw portion 52c is formed on the outer peripheral surface on the lower side of the power transmission portion 52b. The power transmission portion 52b is screwed into the shaft passage 51j of the body portion 51. That is, the female screw portion 51f of the shaft passage 51j and the male screw portion 52c of the power transmission portion 52b are screwed together. Therefore, based on the forward and reverse rotations of the output shaft 52a of the drive mechanism 52 and the power transmission portion 52b, the inner guide portion 54 and the valve body 55 connected to the power transmission portion 52b are linearly reciprocated (i.e., lifted and lowered) in the vertical direction (i.e., the axial direction). At this time, a feed screw mechanism 57 is constituted by the male screw portion 52c of the power transmission portion 52b and the female screw portion 51f of the shaft passage 51j.

[0081] A coil spring 56 is interposed between the lower surface of the guide side disk portion 54a of the inner guide portion 54 and the lower wall portion 53b of the outer guide portion 53. The coil spring 56 is concentrically arranged on the outer peripheral side of the guide side cylindrical portion 54b of the inner guide portion 54. The coil spring 56 prevents backlash of the feed screw mechanism 57 by constantly biasing the inner guide portion 54 upward.

[0082] The valve body 55 is formed in a substantially inverted T shape in a cross section viewed from a direction perpendicular to the axial direction of the valve chamber 51a. The valve body 55 has a valve side disk portion 55a and a valve side cylindrical portion 55b. Both the valve side disk portion 55a and the valve side cylindrical portion 55b are formed concentrically with respect to the valve chamber 51a. The valve side disk portion 55a is disposed on the lower surface of the valve side cylindrical portion 55b. The diameter of the valve side cylindrical portion 55b is smaller than the diameter of the valve side disk portion 55a.

[0083] The upper surface of the valve side cylindrical portion 55b is connected to the guide side cylindrical portion 54b of the inner guide portion 54. The diameter of the valve side cylindrical portion 55b is equal to the diameter of the guide side cylindrical portion 54b.

[0084] The valve-side cylindrical portion 55b is inserted through the through-hole 53c in the lower wall portion 53b of the outer guide portion 53. The diameter of the valve-side cylindrical portion 55b is slightly smaller than the diameter of the through-hole 53c. The valve-side disc portion 55a is disposed outside the outer guide portion 53 in the valve chamber 51a, that is, on the lower side of the outer guide portion 53.

[0085] Incidentally, the drive mechanism 52 of the evaporation pressure regulating valve 19 is controlled in its operation by a control signal output from the air-conditioning control device 100. More specifically, the air-conditioning control device 100 controls the throttle opening degree of the refrigerant flow path in the evaporation pressure regulating valve 19 based on the refrigerant evaporation temperature (i.e., the evaporator temperature) in the indoor evaporator 18.

[0086] The refrigerant evaporation temperature in the indoor evaporator 18 is detected by an evaporator temperature sensor 18a (see FIG. 1). Specifically, in the evaporator temperature sensor 18a of the present embodiment, the heat exchange fin temperature of the indoor evaporator 18 is detected.

[0087] Next, the flow rate characteristics of the evaporation pressure regulating valve 19 of the present embodiment will be described with reference to the drawings. As shown in FIG. 3, the evaporation pressure regulating valve 19 of the present embodiment has a flow rate characteristic in which the degree of increase in the refrigerant flow rate with respect to the opening degree is greater when the opening degree is larger. Note that the degree of increase in the refrigerant flow rate with respect to the opening degree corresponds to the slope of the graph in FIG. 3.

[0088] In other words, the evaporation pressure regulating valve 19 of the present embodiment has a flow rate characteristic in which the degree of increase in the refrigerant flow rate with respect to the opening degree in the low opening degree range where the throttle opening degree is smaller than a predetermined first reference opening degree is less than the degree of increase in the refrigerant flow rate with respect to the opening degree in the high opening degree range where the throttle opening degree is larger than a second reference opening degree that is equal to or greater than the first reference opening degree. The low opening degree range is an opening degree range where the throttle opening degree is smaller than a predetermined first reference opening degree. The high opening degree range is an opening degree range where the throttle opening degree is larger than a second reference opening degree that is equal to or greater than the first reference opening degree.

[0089] That is, the evaporation pressure regulating valve 19 of the present embodiment has a flow rate characteristic having a transition region (in this example, transition point S1) where the rate of increase in the refrigerant flow rate with respect to the increase in the opening degree switches from a state where it is small to a state where it is large between the minimum and maximum throttle opening degrees. The rate of increase in the refrigerant flow rate with respect to the increase in the opening degree in the region R1 where the throttle opening degree is smaller than the transition point S1 is smaller than the rate of increase in the refrigerant flow rate with respect to the increase in the opening degree in the region R2 where the throttle opening degree is larger than the transition point S1. In the evaporation pressure regulating valve 19 of the present embodiment, the refrigerant flow rate when the throttle opening degree is minimum is set to 0.

[0090] As described above, since the evaporation pressure regulating valve 19 of the present embodiment is driven by the drive mechanism 52 which is an electric actuator, the opening degree does not depend on the pressure of the refrigerant on the outlet side of the indoor evaporator 18. Therefore, even when the refrigerant flow rate is large, the opening degree of the evaporation pressure regulating valve 19 can be increased. Thereby, during the dehumidifying heating operation, the fin temperature of the indoor evaporator 18 can be sufficiently lowered, so that the performance of the refrigeration cycle can be improved.

[0091] This will be described with reference to FIG. 4. In FIG. 4, the relationship between the refrigerant flow rate and the refrigerant temperature on the outlet side of the indoor evaporator 18 when the evaporation pressure regulating valve 19 of the present embodiment driven by the drive mechanism 52 which is an electric actuator is used is shown by a thick solid line. Also, as a comparative example, the relationship between the refrigerant flow rate and the refrigerant temperature on the outlet side of the indoor evaporator 18 when a mechanical evaporation pressure regulating valve that increases the valve opening degree as the pressure of the refrigerant on the outlet side of the indoor evaporator 18 increases is used is shown by a thick one-dot chain line.

[0092] As shown by the broken line a and the solid line b in FIG. 4, when the refrigerant flow rate in the indoor evaporator 18 increases, the pressure loss of the refrigerant in the indoor evaporator 18 increases, and the pressure of the refrigerant on the outlet side of the indoor evaporator 18 decreases. At this time, in the comparative example, since a mechanical evaporation pressure regulating valve is used, the valve opening degree becomes small and it does not open at an appropriate opening degree. As a result, the refrigerant discharge capacity of the compressor 11 reaches its peak.

[0093] On the one hand, in this embodiment, since the evaporation pressure regulating valve 19 is an electric valve, even if the pressure of the refrigerant on the outlet side of the indoor evaporator 18 decreases when the refrigerant flow rate increases, the valve can be forcibly opened. As a result, the refrigerant discharge capacity of the compressor 11 can be improved, and thus the performance of the refrigeration cycle can be improved.

[0094] Moreover, the evaporation pressure regulating valve 19 of this embodiment has a flow rate characteristic in which the degree of increase in the refrigerant flow rate with respect to the opening degree is greater when the opening degree is larger. Therefore, when the refrigerant flow rate is small, the degree of increase in the refrigerant flow rate with respect to the opening degree can be reduced. As a result, during the cooling operation, the refrigerant flow rate can be finely adjusted, and thus the performance of the refrigeration cycle can be improved. Therefore, according to the evaporation pressure regulating valve 19 of this embodiment, the performance of the refrigeration cycle can be improved regardless of the operating conditions.

[0095] By the way, in the refrigerant flow path in the body portion 51 of the evaporation pressure regulating valve 19, if the angle formed by the flow of the refrigerant from the inlet portion 51g toward the valve body 55 and the flow of the refrigerant from the valve body 55 toward the outlet portion 51h is less than 90°, the pressure loss in the refrigerant flow path will increase.

[0096] In contrast, in the evaporation pressure regulating valve 19 of this embodiment, the angle formed by the flow of the refrigerant from the inlet portion 51g toward the valve body 55 and the flow of the refrigerant from the valve body 55 toward the outlet portion 51h in the refrigerant flow path in the body portion 51 is set to 90°. According to this, an increase in the pressure loss in the refrigerant flow path in the evaporation pressure regulating valve 19 can be suppressed.

[0097] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. 5. In this embodiment, the flow rate characteristic of the evaporation pressure regulating valve 19 is changed with respect to the first embodiment.

[0098] As shown in Fig. 5, in the evaporation pressure regulating valve 19 of the present embodiment, the refrigerant flow rate when the throttle opening degree is minimum is set to be greater than 0. That is, the evaporation pressure regulating valve 19 of the present embodiment is set such that the refrigerant flow rate becomes greater than 0 at the minimum opening degree. According to this, the differential pressure in the evaporation pressure regulating valve 19 can be reduced, so that it is possible to operate without providing a speed reducer in the drive mechanism 52 (for example, a stepping motor).

[0099] (Third Embodiment) Next, a third embodiment of the present invention will be described with reference to Figs. 6 and 7. In this embodiment, the configuration of the valve body 55 of the evaporation pressure regulating valve 19 is changed with respect to the first embodiment.

[0100] As shown in Fig. 6, in the evaporation pressure regulating valve 19 of the present embodiment, a needle valve is adopted as the valve body 55. That is, in the present embodiment, the valve body 55 is formed in a shape that tapers toward the tip.

[0101] More specifically, the tip of the valve body 55 is formed in a tapered shape in which the cross-sectional area perpendicular to the axial direction becomes smaller as it moves away from the drive mechanism 52 (that is, as it approaches the tip). Hereinafter, the angle formed by the surface of the valve body 55 (that is, the tapered surface) and the axial direction is referred to as the taper angle.

[0102] The tip of the valve body 55 is provided with a first tip 551 and a second tip 552 having different taper angles. The first tip 551 is disposed closer to the tip side than the second tip 552. The taper angle of the first tip 551 is larger than the taper angle of the second tip 552.

[0103] The first tip 551 and the second tip 552 are directly connected. That is, no other member is interposed between the first tip 551 and the second tip 552. The first tip 551 and the second tip 552 are integrally formed.

[0104] As shown in FIG. 7, the evaporation pressure regulating valve 19 of the present embodiment, like that of the first embodiment, has a flow rate characteristic in which the degree of increase in the refrigerant flow rate with respect to the opening increases as the opening becomes larger. At this time, the larger the taper angle at the tip of the valve body 55, the greater the degree of increase in the refrigerant flow rate with respect to the opening.

[0105] Other configurations are the same as those of the first embodiment. Therefore, even in the evaporation pressure regulating valve 19 of the third embodiment, the same effects as those of the first embodiment can be obtained.

[0106] (Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIGS. 8 and 9. In this embodiment, the configuration of the valve body 55 of the evaporation pressure regulating valve 19 is changed with respect to the third embodiment.

[0107] As shown in FIG. 8, the evaporation pressure regulating valve 19 of the present embodiment has a stepped surface 553 between the first tip portion 551 and the second tip portion 552. The stepped surface 553 is formed in a planar shape perpendicular to the axial direction. That is, the angle formed by the stepped surface 553 and the axial direction is 90°.

[0108] As shown in FIG. 9, the evaporation pressure regulating valve 19 of the present embodiment has a flow rate characteristic having a transition region S2 in which the increase ratio of the refrigerant flow rate with respect to the increase in the opening switches from a small state to a large state between the minimum and maximum throttle openings. The increase ratio of the refrigerant flow rate with respect to the increase in the opening in the small opening region R1 where the throttle opening is smaller than the transition region S2 is smaller than the increase ratio of the refrigerant flow rate with respect to the increase in the opening in the large opening region R2 where the throttle opening is larger than the transition region point S2. Further, in the present embodiment, when the opening increases from the small opening region R1 to the large opening region R2, in the transition region S2, with the throttle opening being constant, only the refrigerant flow rate increases.

[0109] Other configurations are the same as those of the third embodiment. Therefore, even in the evaporation pressure regulating valve 19 of the fourth embodiment, the same effects as those of the third embodiment can be obtained.

[0110] (Fifth Embodiment) Next, a fifth embodiment of the present invention will be described with reference to FIGS. 10 and 11. In this embodiment, the configuration of the valve body 55 of the evaporation pressure regulating valve 19 is changed with respect to the third embodiment.

[0111] As shown in FIG. 10, the evaporation pressure regulating valve 19 of this embodiment has a flat surface 554 between the first tip portion 551 and the second tip portion 552. The flat surface 554 is formed in a planar shape parallel to the axial direction. That is, the angle formed by the flat surface 554 and the axial direction is 0°.

[0112] As shown in FIG. 11, the evaporation pressure regulating valve 19 of this embodiment has a flow rate characteristic having a transition region S2 in which the ratio of increase in the refrigerant flow rate with respect to the increase in the opening degree switches from a small state to a large state between the minimum and maximum throttle opening degrees. The ratio of increase in the refrigerant flow rate with respect to the increase in the opening degree in the small opening region R1 where the throttle opening degree is smaller than the transition region S2 is smaller than the ratio of increase in the refrigerant flow rate with respect to the increase in the opening degree in the large opening region R2 where the throttle opening degree is larger than the transition region point S2. Further, in this embodiment, when the opening degree increases from the small opening region R1 to the large opening region R2, in the transition region S2, the refrigerant flow rate remains constant even if the throttle opening degree increases.

[0113] Other configurations are the same as those of the third embodiment. Therefore, also in the evaporation pressure regulating valve 19 of the fifth embodiment, the same effects as those of the third embodiment can be obtained.

[0114] (Sixth Embodiment) Next, a sixth embodiment of the present invention will be described with reference to FIGS. 12 to 14. In this embodiment, the configuration of the evaporation pressure regulating valve 19 is changed with respect to the first embodiment.

[0115] As shown in FIGS. 12 and 13, the evaporation pressure regulating valve 19 of this embodiment is constituted by a disk valve. Specifically, the evaporation pressure regulating valve 19 of this embodiment has a valve box 61, a valve seat 62, and a valve body 63.

[0116] The valve box 61 is a box-shaped member that constitutes the refrigerant flow path 610 and corresponds to the body part. An inlet pipe 61a and an outlet pipe 61b are connected to the valve box 61. The inlet pipe 61a is an inlet part for allowing the refrigerant flowing out from the indoor evaporator 18 to flow in. The outlet pipe 61b is an outlet part for allowing the refrigerant to flow out to the suction port side of the compressor 11.

[0117] The valve seat 62 and the valve body 63 are housed inside the valve box 61. Both the valve seat 62 and the valve body 63 are formed in a disk shape (i.e., circular disk shape). A valve hole 62a communicating with the inlet pipe 61a is formed in the valve seat 62. A communication hole 63a extending in the circumferential direction is formed in the valve body 63. In the present embodiment, the communication hole 63a is formed in a tapered shape in which the opening area gradually expands from the rear side to the front side in the clockwise direction in the plane of FIG. 12.

[0118] The valve seat 62 and the valve body 63 are overlapped so that their central axes coincide. Then, the valve body 63 is slid and rotated around the central axis with respect to the valve seat 62 by a predetermined angle to open and close the valve hole 62a.

[0119] The valve body 63 has a rotation axis of a stepping motor, which is a drive mechanism not shown, connected to its rotation center axis. The operation of the stepping motor is controlled by a control signal output from an air-conditioning control device not shown. Therefore, in the evaporation pressure regulating valve 19 of the present embodiment, the valve body 63 can be rotated by an arbitrary angle around the central axis with respect to the valve seat 62 according to the control signal output from the air-conditioning control device.

[0120] By rotating the valve body 63 in the counterclockwise direction in the plane of FIG. 13, the throttle opening degree increases, and by rotating the valve body 63 in the clockwise direction in the plane of FIG. 13, the throttle opening degree decreases. At this time, since the communication hole 63a is formed in a tapered shape, as shown in FIG. 14, the evaporation pressure regulating valve 19 of the present embodiment has a flow rate characteristic in which the degree of increase in the refrigerant flow rate with respect to the opening degree is greater when the opening degree is larger.

[0121] Other configurations are the same as those in the first embodiment. Therefore, the evaporation pressure regulating valve 19 of the sixth embodiment can also achieve the same effects as those in the first embodiment.

[0122] (Seventh Embodiment) Next, a seventh embodiment of the present invention will be described with reference to FIGS. 15 and 16. In this embodiment, the shape of the communication hole 63a of the valve body 63 is changed with respect to the sixth embodiment.

[0123] As shown in FIG. 15, in the evaporation pressure regulating valve 19 of this embodiment, the communication hole 63a has a narrow groove portion 63b and a wide groove portion 63c. The radial width in the narrow groove portion 63b is narrower than the radial width in the wide groove portion 63c. In the valve body 63, the narrow groove portion 63b is disposed on the rear side in the clockwise direction with respect to the wide groove portion 63c. The narrow groove portion 63b and the wide groove portion 63c are directly communicated.

[0124] In the narrow groove portion 63b, the radial length is constant from the front side to the rear side in the clockwise direction. In the wide groove portion 63c, the radial length gradually increases from the rear side to the front side in the clockwise direction.

[0125] Since the communication hole 63a is configured as described above, the evaporation pressure regulating valve 19 of this embodiment has a flow rate characteristic having a transition region S2 in which, as shown in FIG. 16, between the minimum and maximum throttle openings, the rate of increase in the refrigerant flow rate with respect to the increase in the opening changes from a small state to a large state. The rate of increase in the refrigerant flow rate with respect to the increase in the opening in the small opening region R1 where the throttle opening is smaller than the transition region S2 is smaller than the rate of increase in the refrigerant flow rate with respect to the increase in the opening in the large opening region R2 where the throttle opening is larger than the transition region point S2. Further, in this embodiment, when the opening increases from the small opening region R1 to the large opening region R2, in the transition region S2, only the refrigerant flow rate increases while the throttle opening is in a constant state.

[0126] Other configurations are the same as those in the sixth embodiment. Therefore, the evaporation pressure regulating valve 19 of the seventh embodiment can also achieve the same effects as those in the sixth embodiment.

[0127] (Eighth Embodiment) Next, the eighth embodiment of the present invention will be described with reference to FIGS. 17 and 18. In this embodiment, the configuration of the evaporation pressure regulating valve 19 is changed with respect to the first embodiment.

[0128] As shown in FIG. 17, the evaporation pressure regulating valve 19 of this embodiment is constituted by a butterfly valve. Specifically, the evaporation pressure regulating valve 19 of this embodiment has a valve box 71, a valve shaft 72, a valve body 73, a valve body valve seat 74, and a valve box valve seat 75.

[0129] The valve box 71 is a box-shaped member that constitutes the refrigerant flow path 710 and corresponds to the body portion. An inflow path 71a and an outflow path 71b are connected to the valve box 71. The inflow path 71a is an inlet portion for allowing the refrigerant flowing out from the indoor evaporator 18 to flow in. The outflow path 71b is an outlet portion for allowing the refrigerant to flow out to the suction port side of the compressor 11.

[0130] The valve shaft 72 is a shaft member that penetrates the valve box 71 in the radial direction of the valve shaft 72. The valve body 73 is formed in a disk shape and is attached to the valve shaft 72. The valve body valve seat 74 is provided on the entire outer peripheral surface of the valve body 73. The valve box valve seat 75 is provided on the inner wall surface of the valve box 71 and the valve body valve seat 74 comes into contact with and separates from it.

[0131] A rotating shaft of a stepping motor, which is a drive mechanism not shown in the figure, is connected to the valve shaft 72. The operation of the stepping motor is controlled by a control signal output from an air-conditioning control device not shown in the figure. Therefore, in the evaporation pressure regulating valve 19 of this embodiment, according to the control signal output from the air-conditioning control device, the valve body 73 is rotated via the valve shaft 72 to bring the valve body valve seat 74 into contact with and separate from the valve box valve seat 75, thereby opening and closing the valve.

[0132] Here, in the present embodiment, the valve box valve seat 75 has a tapered surface 75a that is inclined with respect to the refrigerant flow direction (the vertical direction of the paper surface in FIG. 17) of the valve box 71. Therefore, as shown in FIG. 18, the evaporation pressure regulating valve 19 of the present embodiment has a flow rate characteristic in which the degree of increase in the refrigerant flow rate with respect to the opening degree is greater when the opening degree is larger.

[0133] Other configurations are the same as those in the first embodiment. Therefore, even in the evaporation pressure regulating valve 19 of the eighth embodiment, the same effects as those in the first embodiment can be obtained.

[0134] (Ninth Embodiment) Next, the ninth embodiment of the present invention will be described with reference to FIGS. 19 and 20. In the present embodiment, the configuration of the evaporation pressure regulating valve 19 is changed with respect to the eighth embodiment.

[0135] As shown in FIG. 19, the evaporation pressure regulating valve 19 of the present embodiment is constituted by a ball valve. Specifically, the evaporation pressure regulating valve 19 of the present embodiment has a valve box 81, a valve body 82, and a valve rod 83.

[0136] The valve box 81 is a box-shaped member that constitutes the refrigerant flow path 810 and corresponds to the body portion. An inflow path and an outflow path (not shown) are connected to the valve box 81. The inflow path is an inlet portion for allowing the refrigerant flowing out from the indoor evaporator 18 to flow in. The outflow path is an outlet portion for allowing the refrigerant to flow out to the suction port side of the compressor 11.

[0137] The valve body 82 is formed in a spherical shape and is rotatably held in the valve box 81 via a valve seat 84. The valve rod 83 is connected to the upper surface of the valve body 82 and rotates the valve body 82.

[0138] As shown in FIG. 20, in the valve body 82, a refrigerant passage 82a inside the valve is formed to open to the spherical surface. In the valve body 82, a notch groove 82b is formed at the opening of the refrigerant passage 82a inside the valve to the spherical surface and extends in the rotation direction of the valve body 82.

[0139] As shown in Fig. 19, a rotary shaft of a stepping motor, which is a drive mechanism (not shown), is connected to the valve rod 83. The operation of the stepping motor is controlled by a control signal output from an air-conditioning control device (not shown). Therefore, in the evaporation pressure regulating valve 19 of the present embodiment, in response to the control signal output from the air-conditioning control device, the valve body 82 is rotated via the valve rod 83 to switch the communication state between the refrigerant flow path in the valve box 81 and the refrigerant passage 82a inside the valve body 82, thereby opening and closing the valve.

[0140] The evaporation pressure regulating valve 19 of the present embodiment has the same flow rate characteristics as those of the eighth embodiment. Therefore, also in the evaporation pressure regulating valve 19 of the ninth embodiment, the same effects as those of the eighth embodiment can be obtained.

[0141] (Tenth Embodiment) Next, a tenth embodiment of the present invention will be described with reference to Figs. 21 and 22. In this embodiment, the configuration of the evaporation pressure regulating valve 19 is changed with respect to the first embodiment.

[0142] As shown in Fig. 21, the evaporation pressure regulating valve 19 of the present embodiment is constituted by a spool valve. Specifically, the evaporation pressure regulating valve 19 of the present embodiment includes a case 91, a substantially cylindrical valve body 92, and a shaft portion 93.

[0143] The case 91 is a flow path forming portion that constitutes the refrigerant flow path 910 and corresponds to the body portion. In the case 91, a valve chamber 91a, an inflow port 91b, and an outflow port 91c are formed. The valve chamber 91a is a space in which the valve body 92 is accommodated and extends in the axial direction of the valve body 92. The inflow port 91b is an inlet portion for allowing the refrigerant flowing out from the indoor evaporator 18 to flow in. The outflow port 91c is an outlet portion for allowing the refrigerant to flow out to the suction port side of the compressor 11. The opening of the inflow port 91b to the valve chamber 91a and the opening of the outflow port 91c to the valve chamber 91a are arranged on the same plane perpendicular to the axial direction of the valve body 92.

[0144] The valve body 92 is disposed within the valve chamber 91a. The outer diameter of the valve body 92 is slightly smaller than the inner diameter of the valve chamber 91a. The shaft portion 93 is connected to the central portion of one end face in the axial direction of the valve body 92.

[0145] A linear actuator, which is a drive mechanism not shown in the drawings, is connected to the end of the shaft portion 93 on the side not connected to the valve body 92. The linear actuator is an electric actuator that linearly drives. The operation of the linear actuator is controlled by a control signal output from an air-conditioning control device not shown in the drawings. Therefore, in the evaporation pressure regulating valve 19 of the present embodiment, in response to the control signal output from the air-conditioning control device, the shaft portion 93 and the valve body 92 are slid axially to switch the communication state between the inflow port 91b and the outflow port 91c, thereby opening and closing the valve.

[0146] In the present embodiment, the valve body 92 has a first tapered surface 92a and a second tapered surface 92b that are inclined with respect to both the axial direction and the radial direction of the valve body 92. The first tapered surface 92a is disposed closer to the shaft portion 93 than the second tapered surface 92b. The inclination angle of the second tapered surface 92b with respect to the axial direction is larger than the inclination angle of the first tapered surface 92a with respect to the axial direction. The first tapered surface 92a and the second tapered surface 92b are formed continuously.

[0147] Here, as described above, since the valve body 82 has the first tapered surface 92a and the second tapered surface 92b, as shown in FIG. 22, the evaporation pressure regulating valve 19 of the present embodiment has a flow rate characteristic in which the degree of increase in the refrigerant flow rate with respect to the opening increases as the opening becomes larger.

[0148] More specifically, the evaporation pressure regulating valve 19 of the present embodiment has a flow rate characteristic having a first transition point S1 and a second transition point S2 at which the rate of increase in the refrigerant flow rate with respect to the increase in the opening switches from a small state to a large state between the minimum and maximum throttle openings.

[0149] The rate of increase in the refrigerant flow rate with respect to the increase in the opening degree in the region R1 where the opening degree is smaller than the first transition point S1 is smaller than the rate of increase in the refrigerant flow rate with respect to the increase in the opening degree in the regions R2 and R3 where the opening degree is larger than the first transition point S1. Also, the rate of increase in the refrigerant flow rate with respect to the increase in the opening degree in the region R2 where the opening degree is larger than the first transition point S1 and smaller than the second transition point S2 is smaller than the rate of increase in the refrigerant flow rate with respect to the increase in the opening degree in the region R3 where the opening degree is larger than the second transition point S2.

[0150] Other configurations are the same as those in the first embodiment. Therefore, the evaporation pressure regulating valve 19 of the tenth embodiment can also achieve the same effects as those in the first embodiment.

[0151] (Eleventh Embodiment) Next, the eleventh embodiment of the present invention will be described with reference to FIGS. 23 and 24. In this embodiment, the shapes of the case 91 and the valve body 92 are changed with respect to the tenth embodiment.

[0152] As shown in FIG. 23, in the evaporation pressure regulating valve 19 of this embodiment, the valve body 92 is formed in a cylindrical shape. That is, the first tapered surface 92a and the second tapered surface 92b are abolished.

[0153] A narrow groove portion 91d that is notched in a tapered shape is formed at the connection portion between the inflow port 91b and the valve chamber 91a in the case 91. The narrow groove portion 91d is arranged so as to face a corner portion provided on the end surface of the valve body 92 on the side opposite to the shaft portion 93.

[0154] For this reason, as shown in FIG. 24, the evaporation pressure regulating valve 19 of this embodiment has a flow rate characteristic having a transition point S1 at which the rate of increase in the refrigerant flow rate with respect to the increase in the opening degree switches from a small state to a large state between the minimum and maximum opening degrees. The rate of increase in the refrigerant flow rate with respect to the increase in the opening degree in the region where the opening degree is smaller than the transition point S1 is smaller than the rate of increase in the refrigerant flow rate with respect to the increase in the opening degree in the region R2 where the opening degree is larger than the transition point S1.

[0155] The other configurations are the same as those of the tenth embodiment. Therefore, the evaporation pressure regulating valve 19 of the eleventh embodiment can also achieve the same effects as those of the tenth embodiment.

[0156] (The twelfth embodiment) Next, the twelfth embodiment of the present invention will be described with reference to FIGS. 25 and 26. In this embodiment, the configuration of the evaporation pressure regulating valve 19 is changed with respect to the eleventh embodiment.

[0157] As shown in FIGS. 25 and 26, the evaporation pressure regulating valve 19 of this embodiment is constituted by a slide valve. Specifically, the evaporation pressure regulating valve 19 of this embodiment has a valve box 101, an inflow port 102, an outflow port 103, and a valve body 104.

[0158] The valve box 101 is a box-shaped member that constitutes the refrigerant flow path 1010 and corresponds to the body portion. The inflow port 102 and the outflow port 103 are connected to the valve box 101. The inflow port 102 is an inlet portion for allowing the refrigerant flowing out from the indoor evaporator 18 to flow in. The outflow port 103 is an outlet portion for allowing the refrigerant to flow out to the suction port side of the compressor 11.

[0159] The inflow port 102 and the outflow port 103 are each formed in a cylindrical shape. The inflow port 102 is connected to one end side in the refrigerant flow direction in the valve box 101 (the upper side on the paper surface of FIG. 26). The outflow port 103 is connected to the other end side in the refrigerant flow direction in the valve box 101 (the lower side on the paper surface of FIG. 26).

[0160] Here, the central axis of the refrigerant flow path in each port 102, 103 is referred to as the flow path axis. The flow path axis of the inflow port 102 is arranged on the same straight line as the flow path axis of the outflow port 103. That is, the inflow port 102 faces the outflow port 103 with the valve box 101 interposed therebetween.

[0161] The upstream end of the outflow port 103 is disposed within the valve box 101. A valve seat surface 105 is formed on the upstream end face of the outflow port 103. Hereinafter, the portion of the outflow port 103 disposed within the valve box 101 is referred to as a valve seat portion 106. The valve seat portion 106 is formed in a cylindrical shape.

[0162] The valve body 104 is formed in a disc shape. When viewed from the axial direction, the diameter of the valve body 104 is larger than the diameter of the opening of the outflow port 103. The valve body 104 is provided to abut against the valve seat surface 105 and opens and closes the outflow port by sliding in a direction orthogonal to the flow path axis.

[0163] A linear actuator, which is a drive mechanism not shown in the drawings, is connected to the valve body 104. The operation of the linear actuator is controlled by a control signal output from an air-conditioning control device not shown in the drawings. For this reason, in the evaporation pressure regulating valve 19 of the present embodiment, according to the control signal output from the air-conditioning control device, the valve body 104 is slid to switch the communication state of the outflow port 103, thereby opening and closing the valve.

[0164] Here, on the inner peripheral surface of the valve seat portion 106 on the side opposite to the drive mechanism, a narrow groove portion 107 that is radially notched is provided. The bottom surface of the narrow groove portion 107 (that is, the surface far from the valve body 104) is formed in a tapered shape that slopes away from the flow path axis of the outflow port 103 as it approaches the valve body 104.

[0165] For this reason, the evaporation pressure regulating valve 19 of the present embodiment has the same flow rate characteristics as those of the 11th embodiment. Therefore, also in the evaporation pressure regulating valve 19 of the 12th embodiment, the same effects as those of the 11th embodiment can be obtained.

[0166] (Other Embodiments) The present invention is not limited to the above-described embodiments, and various modifications can be made as follows without departing from the gist of the present invention. Also, the means disclosed in the above-described embodiments may be appropriately combined within the scope of feasibility.

[0167] (1) In the above-described eighth embodiment, an example in which the evaporation pressure regulating valve 19 is configured by a butterfly valve and the valve box valve seat 75 is provided with a tapered surface 75a has been described, but the present invention is not limited to this aspect. For example, as shown in FIG. 27, the valve box valve seat 75 may be formed in a stepped shape. In this case, the flow rate characteristics of the evaporation pressure regulating valve 19 can be made the same as those in the fourth embodiment.

[0168] (2) In the above-described tenth embodiment, an example in which the evaporation pressure regulating valve 19 is configured by a spool valve and the valve body 92 is provided with a first tapered surface 92a and a second tapered surface 92b has been described, but the present invention is not limited to this aspect. For example, as shown in FIG. 28, a small-diameter portion 92c having a smaller radial dimension than other portions may be provided on the side of the valve body 92 far from the shaft portion 93. In this case, the flow rate characteristics of the evaporation pressure regulating valve 19 can be made the same as those in the eleventh embodiment.

[0169] (3) In the above-described embodiments, an example in which the refrigerant flow rate increases linearly as the opening degree increases has been described as the flow rate characteristics of the evaporation pressure regulating valve 19, but the flow rate characteristics are not limited to this aspect. For example, as shown in FIG. 29, the refrigerant flow rate may increase curvilinearly as the opening degree increases.

[0170] (4) In the above-described embodiments, an example in which an electric motor is adopted as the electric actuator has been described, but other electric actuators such as a solenoid may be adopted as the electric actuator.

[0171] (5) In the above-described first embodiment, an example in which the angle formed by the flow of the refrigerant from the inlet portion 51g toward the valve body 55 and the flow of the refrigerant from the valve body 55 toward the outlet portion 51h in the refrigerant flow path (i.e., the valve chamber 51a) in the body portion 51 is 90° has been described, but the present invention is not limited to this aspect. The angle formed by the flow of the refrigerant from the inlet portion 51g toward the valve body 55 and the flow of the refrigerant from the valve body 55 toward the outlet portion 51h may be any angle of 90° or more.

[0172] (6) In the above-described embodiment, an example of controlling the throttle opening degree of the refrigerant flow path in the evaporation pressure regulating valve 19 based on the refrigerant evaporation temperature (i.e., the evaporator temperature) in the indoor evaporator 18 has been described. However, the opening degree control of the evaporation pressure regulating valve 19 is not limited to this mode.

[0173] For example, the throttle opening degree of the refrigerant flow path in the evaporation pressure regulating valve 19 may be controlled based on the temperature of the refrigerant on the inlet side of the indoor evaporator 18. Further, the throttle opening degree of the refrigerant flow path in the evaporation pressure regulating valve 19 may be controlled based on the pressure of the refrigerant on the inlet side of the indoor evaporator 18. Also, the throttle opening degree of the refrigerant flow path in the evaporation pressure regulating valve 19 may be controlled based on the pressure reduction amount in the second expansion valve 15b. Further, the throttle opening degree of the refrigerant flow path in the evaporation pressure regulating valve 19 may be controlled based on the outlet side pressure of the refrigerant flowing out from the second expansion valve 15b.

[0174] (7) In the above-described embodiment, an example of connecting the inlet side of the evaporation pressure regulating valve 19 to the refrigerant outlet of the indoor evaporator 18 has been described. However, the arrangement of the evaporation pressure regulating valve 19 is not limited to this mode. For example, the inlet side of the evaporation pressure regulating valve 19 may be connected to the refrigerant outlet of the outdoor heat exchanger 16.

Explanation of Reference Numerals

[0175] 10 Refrigeration cycle device (refrigeration cycle) 11 Compressor 18 Indoor evaporator (evaporator) 52 Driving mechanism (electric actuator)

Claims

1. An evaporator pressure regulating valve disposed between an evaporator (16, 18) and a compressor (11) in a refrigeration cycle (10), and configured to adjust the refrigerant evaporation pressure in the evaporator to be equal to or higher than a predetermined reference evaporation pressure, driven by an electric actuator (52), wherein the degree of increase in refrigerant flow rate with respect to the opening degree is greater when the opening degree is larger, a body portion (51, 61, 71, 81, 91, 101) having an inlet portion (51g, 61a, 71a, 91b, 102) for allowing the refrigerant flowing out from the evaporator to flow in, a refrigerant flow path (51a, 610, 710, 810, 910, 1010) for allowing the refrigerant flowing in from the inlet portion to flow through, and an outlet portion (51h, 61b, 71b, 91c, 103) for allowing the refrigerant flowing through the refrigerant flow path to flow out to the suction port side of the compressor, a valve body (55, 63, 73, 82, 92, 104) for adjusting the throttle opening degree of the refrigerant flow path, and an evaporator pressure regulating valve that controls the throttle opening degree of the refrigerant flow path based on the pressure reduction amount in a pressure reduction portion (15b) for reducing the pressure of the refrigerant discharged from the compressor. Evaporator pressure regulating valve.

2. The evaporator pressure regulating valve according to claim 1, having a transition region in which the degree of increase in refrigerant flow rate with respect to the opening degree switches from a small state to a large state between the minimum opening degree and the maximum opening degree.

3. The evaporator pressure regulating valve according to claim 1 or 2, wherein the refrigerant flow rate is greater than 0 at the minimum opening degree.

4. The evaporator pressure regulating valve according to any one of claims 1 to 3, wherein the angle formed by the flow of the refrigerant from the inlet portion toward the valve body and the flow of the refrigerant from the valve body toward the outlet portion is 90° or more.

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