JP2009024945A - Expansion valve with solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expansion valve with a solenoid valve, enabling a power element to accurately sense the temperature of an outlet refrigerant of an evaporator. <P>SOLUTION: The expansion valve with the solenoid valve includes a body 16 constituted by a main cylindrical part 14 and a sub-cylindrical part 15, wherein the side of the main cylindrical part 14 connected to a rear evaporator 7 and the opposite side thereto have a coaxially disposed double-pipe structure. The whole periphery of an outer pipe on the opposite side to the side of the main cylindrical part 14 connected to the rear evaporator 7 is caulked to fix the outer peripheral edge part of the power element 35 to the body 16. Thus, an opening part of a lower housing 37 inside the power element 35 can be enlarged, whereby the outlet refrigerant of the rear evaporator 7 can be easily caused to reach the temperature sensing part of the power element so that the temperature of the outlet refrigerant of the evaporator can be accurately sensed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an expansion valve with an electromagnetic valve in which an electromagnetic valve and an expansion valve are integrated, and is used particularly in a rear side circuit of an automotive air conditioner capable of independently air-conditioning a front side and a rear side in a vehicle interior. The present invention relates to an expansion valve with a solenoid valve.

  2. Description of the Related Art Conventionally, there has been known an automobile air conditioner that can independently air-condition a front side and a rear side of a vehicle interior. In such an automobile air conditioner, a front expansion valve and an evaporator circuit for controlling the air conditioning on the front side and a rear expansion valve and an evaporator circuit for performing the air conditioning control on the rear side are arranged in parallel. A refrigeration cycle configured as described above is used.

  Here, when the automobile air conditioner is in operation, there are cases where the rear side performs air conditioning control only on the front side without performing air conditioning control depending on the passenger's boarding situation. When the rear-side air conditioning control is not performed in this way, the solenoid valve installed in the rear-side circuit is closed so that the refrigerant does not flow into the rear-side circuit. As the electromagnetic valve used for such an application, an expansion valve with an electromagnetic valve configured integrally with the expansion valve is used from the viewpoint of installation space and cost.

  The solenoid valve in such an expansion valve with a solenoid valve is disposed downstream of the valve body of the expansion valve, and is closed when the rear side air conditioning control is not performed. Here, when the expansion valve with solenoid valve closes the solenoid valve and the front side continues air conditioning control, the expansion valve with solenoid valve controls the opening degree by sensing the temperature of the outlet of the evaporator on the rear side The temperature sensing part is exposed to a high room temperature, and the expansion valve is controlled to be fully opened. In addition, since the air conditioning control is continued on the front side, the upstream side of the expansion valve is at a high pressure and the downstream side of the solenoid valve is at a low pressure even on the rear side provided in parallel therewith. Yes. For this reason, in this situation, when the solenoid valve is opened to perform air conditioning on the rear side, a large flow amount of refrigerant suddenly flows through the fully opened expansion valve due to the differential pressure before and after that, and a large flow of refrigerant flows. It sometimes occurred.

  In order to suppress the occurrence of such refrigerant flow noise, when the solenoid valve is closed, the expansion valve is closed by applying the high pressure on the upstream side of the expansion valve to the diaphragm of the temperature sensing unit. In order to prevent a large flow rate of refrigerant from flowing when the solenoid valve is opened. In such an expansion valve with a solenoid valve, a high pressure pressure is directly applied to the diaphragm of the temperature sensing unit, and therefore the diaphragm and the housing constituting the temperature sensing chamber use a high pressure resistant material.

On the other hand, an expansion valve with a solenoid valve has been proposed in which a high pressure pressure is not directly applied to the diaphragm of the temperature sensing unit, and a normal element that is not a high withstand pressure specification is used as a power element including a temperature sensing greenhouse. (For example, refer to Patent Document 1). This expansion valve with a solenoid valve incorporates a valve portion of an expansion valve and has a rectangular parallelepiped body having the function of a joint to which four pipes are connected, and is coupled to this body to control the valve portion of the expansion valve. A pressure element that is adjacent to the power element and includes a power element and an electromagnetic valve that opens and closes a passage between the downstream side of the valve unit connected to the body and a low-pressure refrigerant outlet connected to the evaporator inlet. Is provided. The pressure chamber is constituted by a guide member communicating with the upstream side of the solenoid valve and a stopper member in contact with the diaphragm. The guide member has a large-diameter portion housed in the housing on the side where the power element is screwed to the body, and the stopper member is movable in the displacement direction of the power element through the seal member therein. It is inserted. In this expansion valve with solenoid valve, the pressure chamber communicates with the upstream side of the solenoid valve, so when the solenoid valve opens, the pressure chamber is equalized with the low pressure at the outlet of the expansion valve, and the expansion valve Functions as an expansion valve. When the solenoid valve is closed, a high pressure is introduced into the pressure chamber, and the stopper member urges the diaphragm away from the valve body, so that the expansion valve is fully closed. As a result, when the solenoid valve is opened to start rear-side air conditioning, the expansion valve is closed when the valve is opened, so that a large flow rate of refrigerant does not flow suddenly and the generation of refrigerant flow noise is suppressed. can do.
JP 2004-150656 A

  However, the expansion valve with electromagnetic valve described in the cited document 1 is arranged so that the large diameter portion of the guide member closes the opening of the housing on the side where the power element is screwed to the body. There is a problem in that the refrigerant at the outlet of the evaporator is difficult to be introduced therein, and the power element cannot correctly detect the temperature and pressure of the refrigerant at the outlet of the evaporator.

  This invention is made | formed in view of such a point, and it aims at providing the expansion valve with an electromagnetic valve in which a power element can sense the temperature of an evaporator exit refrigerant | coolant correctly.

  In the present invention, in order to solve the above problem, in an expansion valve with an electromagnetic valve that integrates an expansion valve that adiabatically expands a refrigerant and an electromagnetic valve that can close the expansion valve, both ends have a double tube structure. A body having a formed main cylindrical portion and a pipe connecting portion extending in a direction orthogonal to the main cylindrical portion, and a first outer tube on one end side of the main cylindrical portion are disposed so as to be airtightly closed. Between the power element and the first inner pipe on one end side of the main cylindrical portion, the power element is fitted in an airtight manner so as to be capable of moving forward and backward in the axial direction while being in contact with the power element, and between the end face of the first inner pipe Is accommodated in a space formed in an axial direction between a piston in which a pressure chamber is formed and the first inner pipe on one end side of the main cylindrical portion and the second inner pipe on the other end side, and the pipe A passage between the high-pressure inlet of the connecting portion and the second inner pipe of the main cylindrical portion is connected to the power A valve part that opens and closes in conjunction with the movement of the element and the piston, and is arranged in a communication path between the pressure chamber of the piston and the second inner pipe of the main cylindrical part, and closes when not energized, An electromagnetic valve-equipped expansion valve is provided. The electromagnetic valve opens when energized.

  According to such an expansion valve with a solenoid valve, by closing the first outer tube on the side opposite to the side to which the evaporator is connected in the main cylindrical portion of the body with the power element, Thus, the opening of the housing on the side receiving the low-pressure refrigerant can be enlarged, and the power element can correctly sense the temperature of the evaporator outlet refrigerant.

  The expansion valve with a solenoid valve according to the present invention has a structure in which the outer pipe of the double pipe structure in the main cylindrical part of the body is closed by the power element, so that the opening of the housing inside the power element can be enlarged. As a result, the evaporator outlet refrigerant can easily reach the temperature sensing portion of the power element, and therefore there is an advantage that the temperature of the evaporator outlet refrigerant can be correctly detected.

  Also, by making the effective pressure receiving diameters of the piston and the diaphragm of the power element equal, the pressure at the outlet of the evaporator is canceled, and the effective pressure receiving diameter of the piston is larger than that of the conventional expansion valve with solenoid valve. Even when the pressure difference between the high pressure and the low pressure is small, such as when the refrigeration load of the engine is very small, the piston that moves due to the differential pressure opens when the temperature sensor senses room temperature and the internal pressure increases. Since it can move in the valve closing direction against the urging force acting in the direction, the valve closed state can be reliably maintained.

  Hereinafter, referring to the drawings, the embodiment of the present invention is applied to an expansion valve for rear side air conditioning of a refrigeration cycle having an internal heat exchanger in order to improve the efficiency of an automotive air conditioner. This will be described in detail.

FIG. 1 is a system diagram showing a refrigeration cycle of an automotive air conditioner.
This refrigeration cycle is arranged in an engine room of a vehicle, and compresses a refrigerant 1, a condenser 2 that cools and condenses the compressed refrigerant, and separates the condensed refrigerant into gas and liquid. And a receiver 3 for sending out liquid refrigerant. A front side expansion valve 4 that squeezes and expands the liquid refrigerant and a front side evaporator 5 that evaporates the expanded refrigerant are disposed on the front side of the vehicle interior, and the liquid refrigerant is throttled on the rear side of the vehicle interior. An expansion valve 6 with a solenoid valve for expansion and a rear side evaporator 7 for evaporating the expanded refrigerant are arranged. The receiver 3 is connected to the front side expansion valve 4 and the expansion valve 6 with a solenoid valve by an internal heat exchanger 8. Further, in the vicinity of the front-side evaporator 5 and the rear-side evaporator 7, blowers 9 and 10 are provided for allowing the air in the vehicle compartment to pass therethrough.

  Here, for example, when air conditioning is performed only on the front side, the compressor 1 and the blower 9 are activated in a state where the expansion valve 6 with the electromagnetic valve closes the refrigerant flow path of the rear side circuit. The high-temperature and high-pressure refrigerant compressed by the compressor 1 is condensed by the condenser 2 and stored in the receiver 3. The liquid refrigerant in the receiver 3 is supplied to the front side expansion valve 4 through the internal heat exchanger 8, where it is throttled and expanded to become a low-temperature / low-pressure refrigerant. The refrigerant that has become a low-temperature and low-pressure refrigerant is sent to the front-side evaporator 5, where it is evaporated by heat exchange with the air in the vehicle compartment sent by the blower 9. The evaporated refrigerant is sent to the inlet of the compressor 1 through the front side expansion valve 4 and the internal heat exchanger 8.

  When the evaporated refrigerant passes through the front side expansion valve 4, the front side expansion valve 4 senses the temperature and pressure of the refrigerant in the front side evaporator 5, and the refrigerant at the outlet of the front side evaporator 5 has a predetermined value. The flow rate of the refrigerant sent to the front-side evaporator 5 is controlled so that the degree of superheat is reached. The internal heat exchanger 8 exchanges heat between the high-temperature refrigerant flowing from the receiver 3 toward the front side expansion valve 4 and the low-temperature refrigerant flowing from the front side expansion valve 4 toward the compressor 1. The refrigerant sent to the side expansion valve 4 is further cooled, and the refrigerant sent to the compressor 1 is further heated, so that the enthalpy difference between the inlet of the front side expansion valve 4 and the inlet of the compressor 1 increases. As a result, the coefficient of performance of the refrigeration cycle is improved, the load of the traveling engine that drives the compressor 1 is reduced, and the efficiency of the automotive air conditioner can be improved.

  When rear-side air conditioning is performed, the solenoid valve of the expansion valve 6 with solenoid valve and the blower 10 are activated. As a result, the high-temperature and high-pressure liquid refrigerant branched by the internal heat exchanger 8 is supplied to the expansion valve 6 with a solenoid valve, where it is throttled and expanded into a low-temperature and low-pressure refrigerant. The refrigerant that has become a low-temperature and low-pressure refrigerant is sent to the rear-side evaporator 7, where it is evaporated by heat exchange with the air in the vehicle compartment sent by the blower 10. The evaporated refrigerant is sent to the inlet of the compressor 1 through the expansion valve 6 with a solenoid valve and the internal heat exchanger 8. When the evaporated refrigerant passes through the expansion valve 6 with a solenoid valve, the expansion valve 6 with a solenoid valve senses the temperature and pressure of the refrigerant in the rear evaporator 7, and the refrigerant at the outlet of the rear evaporator 7 The flow rate of the refrigerant sent to the rear side evaporator 7 is controlled so as to have a predetermined degree of superheat.

  2 is a cross-sectional view showing a non-energized state of the expansion valve with electromagnetic valve according to the first embodiment, FIG. 3 is an enlarged cross-sectional view of part A of FIG. 2, and FIG. 4 is an electromagnetic valve according to the first embodiment. It is sectional drawing which shows the energization state of an attached expansion valve.

  The expansion valve 11 with a solenoid valve according to the first embodiment corresponds to the expansion valve 6 with a solenoid valve in FIG. 1 and is configured to be directly connected to the refrigerant inlet and the refrigerant outlet of the rear side evaporator 7. have. The rear evaporator 7 is configured by laminating a plurality of aluminum plates, and has a refrigerant inlet pipe 12 for introducing a refrigerant and a refrigerant outlet pipe 13 for leading out the refrigerant in a header portion thereof. The refrigerant outlet pipe 13 is arranged coaxially with the refrigerant inlet pipe 12 so as to surround the refrigerant inlet pipe 12. The rear evaporator 7 is formed by simultaneously welding the stacked plates by brazing in the furnace. At this time, the refrigerant inlet pipe 12 and the refrigerant outlet pipe 13 are also welded together. Are integrally formed.

  In the expansion valve 11 with a solenoid valve, a sub-columnar portion 15 extending downward in FIG. 2 is coupled to a main columnar portion 14 extending in the left-right direction in FIG. 2, and the upper side of FIG. A body 16 having an external shape is provided. The sub-cylindrical part 15 constitutes a pipe connection part connected to the pipe of the internal heat exchanger 8. The main cylindrical portion 14 and the sub-cylindrical portion 15 have a double tube structure in their three end face shapes. The main cylindrical portion 14 is formed with a central hole in the center of which the movable portion of the expansion valve is accommodated in the axial direction, and a plurality of low-pressure refrigerant introduced from the rear-side evaporator 7 flows around the central hole. A passage is formed penetrating in the axial direction.

  A shaft guide 17 is press-fitted into the central hole of the main cylindrical portion 14, and a ring-shaped valve seat 18 is fixed to the body 16 by caulking. A valve element 19 is disposed so as to be able to contact and separate from the valve seat 18. The valve body 19 is biased in the valve closing direction by a spring 20, and the spring 20 is press-fitted into a double pipe inner pipe formed on the rear evaporator 7 side of the main cylindrical portion 14. The load of the spring 20 is adjusted by the amount of press-fitting of the spring receiving member 21 into the inner tube.

  The valve body 19 is formed integrally with a shaft 22 that extends in the axial direction via the valve seat 18 and the shaft guide 17. The end of the shaft 22 opposite to the side on which the valve body 19 is formed is fitted to the piston 23. As for piston 23, the center cylindrical part with which shaft 22 is fitted is arrange | positioned in the center hole of the main cylindrical part 14, and the O-ring 24 for a seal | sticker is arrange | positioned at the valve body 19 side of the center cylindrical part. . The piston 23 is also formed with an annular groove 26 that forms a pressure chamber 25 around the central cylindrical portion thereof. The annular groove 26 is formed on the opposite side of the main cylindrical portion 14 from the rear-side evaporator 7. The inner pipe of the double pipe is inserted, and the pressure chamber 25 is sealed by an O-ring 27 provided around the inner pipe.

  The inner pipe of the main cylindrical portion 14 formed in a double pipe structure on the side where the spring receiving member 21 is press-fitted constitutes the low-pressure refrigerant outlet 28 of the expansion valve 11 with electromagnetic valve, and is formed on the outer periphery thereof. The formed annular groove constitutes a return low-pressure refrigerant inlet 29 that receives the refrigerant returned from the rear-side evaporator 7. Here, the low-pressure refrigerant outlet 28 of the expansion valve 11 with a solenoid valve is fitted into the refrigerant inlet pipe 12 of the rear evaporator 7, and the fitting portion is sealed by an O-ring. The return low-pressure refrigerant inlet 29 of the expansion valve 11 with a solenoid valve is fitted into the refrigerant outlet pipe 13 of the rear evaporator 7 and mechanically connected to the rear evaporator 7 by caulking the entire tip. The fitting part with the refrigerant outlet pipe 13 is sealed by an O-ring.

  The installation space of the shaft guide 17 in the central hole of the main cylindrical part 14 communicates with the inner pipe of the double pipe structure formed in the sub cylindrical part 15, and the passage formed around the central hole of the main cylindrical part 14 is The space between the inner pipe and the outer pipe formed in the sub-cylindrical portion 15 is communicated. Here, the inner tube of the sub-cylindrical portion 15 constitutes a high-pressure refrigerant inlet 30, and the space between the inner tube and the outer tube of the sub-cylindrical portion 15 is compressed by the refrigerant that has passed through the expansion valve 11 with the electromagnetic valve. A return low-pressure refrigerant outlet 31 is returned to the inlet of the machine 1. Therefore, the high-pressure refrigerant inlet 30 of the expansion valve with solenoid valve 11 is fitted with a high-pressure pipe 32 to which high-temperature and high-pressure liquid refrigerant from the receiver 3 is supplied and is sealed by an O-ring. The return low-pressure refrigerant outlet 31 of the expansion valve 11 with a solenoid valve is fitted into a return low-pressure pipe 33, and the entire circumference is caulked so as to fix the back-up ring 34 fitted to the tip, thereby returning and low-pressure. The fitting portion that is mechanically coupled to the piping 33 and is connected to the return low-pressure piping 33 is sealed by an O-ring. In this embodiment, the high pressure pipe 32 and the return low pressure pipe 33 connected to the sub-cylindrical portion 15 have a double pipe structure, which constitutes the internal heat exchanger 8 of FIG.

  As described above, the expansion valve 11 with the electromagnetic valve is configured such that the connection with the rear evaporator 7 is a coaxial double pipe structure and is performed by caulking all around the outer pipe, thereby allowing two fluid passages. Since the connection to the rear side evaporator 7 is coaxial, the body 16 is connected to the low pressure refrigerant outlet 28 and the return low pressure refrigerant inlet before joining to the rear side evaporator 7. Therefore, the direction of the opening direction of the high-pressure refrigerant inlet 30 and the return low-pressure refrigerant outlet 31 into which the high-pressure pipe 32 and the return low-pressure pipe 33 are fitted can be freely changed.

  The opposite side of the main cylindrical portion 14 to the side connected to the rear evaporator 7 has a double tube structure, and the opening of the outer tube is closed by a power element 35. The closing by the power element 35 is sealed by caulking the opening end of the outer tube all around so as to lock the outer peripheral edge of the power element 35. The power element 35 includes an upper housing 36 and a lower housing 37, and a diaphragm 38 made of a flexible thin metal plate welded together in a state where the outer peripheral edge portion is sandwiched therebetween. The space surrounded by the upper housing 36 and the diaphragm 38 constitutes a greenhouse, and is filled with a refrigerant gas or the like. In the lower housing 37, the piston 23 is disposed in contact with the diaphragm 38, and the displacement of the diaphragm 38 is transmitted to the valve body 19.

  A mounting hole 40 for the electromagnetic valve 39 is formed on the upper surface of the body 16 in the figure, and a cylindrical valve seat 41 is erected in the mounting hole 40, and the valve hole is formed in the valve seat 18 of the expansion valve. It communicates with the downstream side. The body 16 is formed with a communication path 42 that allows the mounting hole 40 and the pressure chamber 25 to communicate with each other. An orifice member 43 having a through hole with a minute diameter is fitted to the open end of the communication passage 42 opened to the pressure chamber 25. The orifice member 43 has a function of limiting the flow rate of the refrigerant that enters and exits the pressure chamber 25. A high-pressure introduction hole 44 communicating with the upstream side of the valve seat 18 of the expansion valve is provided in the middle of the communication passage 42. Here, the shaft guide 17 that supports the shaft 22 so as to be movable back and forth in the axial direction is integrally formed with a lead piece 45 that closes the high-pressure introduction hole 44 with a minute opening. The high-pressure introduction hole 44 and the lead piece 45 constitute a check valve. That is, normally, in the direction from the upstream side of the valve seat 18 of the expansion valve to the communication passage 42 via the high-pressure introduction hole 44, the flow of the refrigerant is generally stopped, and the high-pressure refrigerant leaks slightly. When the refrigerant pressure in the communication passage 42 suddenly rises, the valve is opened so that the high pressure can be easily released to the upstream side of the valve seat 18 of the expansion valve via the high pressure introduction hole 44.

  The solenoid valve 39 is airtightly fitted with a sleeve 46 in the mounting hole 40 of the body 16, and its open end is closed by a core 47. A plunger 48 is disposed in the sleeve 46 between the core 47 and the valve seat 41, and a valve body 49 is held at an end facing the valve seat 41. A spring 50 is disposed between the plunger 48 and the core 47 in a direction in which the valve body 49 is seated on the valve seat. A coil 51 is provided around the sleeve 46, and is surrounded by a yoke 52. Therefore, in the electromagnetic valve 39, when the coil 51 is not energized, the valve body 49 is seated on the valve seat 41 by the urging force of the spring 50 and is closed. When the coil 51 is energized, the plunger 48 is attracted by the core 47 and the valve body 49 is separated from the valve seat 41 against the urging force of the spring 50, so that the electromagnetic valve 39 is opened.

  In the expansion valve 11 with a solenoid valve having the above configuration, the front side air conditioning is performed, but when the rear side air conditioning is stopped, power is not supplied to the coil 51 of the solenoid valve 39, so that it is shown in FIG. Thus, the electromagnetic valve 39 is closed. Thus, since the high-temperature and high-pressure liquid refrigerant is supplied from the receiver 3 to the high-pressure refrigerant inlet 30 through the high-pressure pipe 32 of the internal heat exchanger 8, the liquid refrigerant passes through the small opening of the check valve 42. And is introduced into the pressure chamber 25 through the orifice member 43. Since the pressure chamber 25 is a closed space sealed by the O-rings 24 and 27, the pressure chamber 25 does not leak any further. Therefore, the high-pressure refrigerant introduced into the pressure chamber 25 causes the piston 23 to be connected to the power element 35. It works to push it out toward. Along with this, the shaft 22 coupled to the piston 23 and the valve body 19 integrated therewith are also moved toward the power element 35, and the movement is stopped when the valve body 19 is seated on the valve seat 18.

  At this time, since the expansion valve is closed, the refrigerant does not flow through the expansion valve 11 with the electromagnetic valve. In addition, since the high-pressure refrigerant drives the piston 23 and forcibly seats the valve element 19 on the valve seat 18, the closed state of the expansion valve can be maintained. Note that the high-pressure liquid refrigerant introduced into the pressure chamber 25 may be warmed due to the air conditioning on the rear side being stopped, and the pressure chamber 25 becomes such an abnormally high pressure. In this case, since the check valve is opened and discharged to the upstream side of the expansion valve, the pressure is reduced, so that adverse effects due to abnormally high pressure can be prevented.

  Here, when the solenoid valve 39 is energized to perform the air conditioning on the rear side, the solenoid valve 39 opens as shown in FIG. Thereby, the high-pressure liquid refrigerant filled in the communication passage 42 and the pressure chamber 25 flows out downstream of the valve seat 18 of the expansion valve through the electromagnetic valve 39. At this time, since the liquid refrigerant in the pressure chamber 25 flows out through the orifice of the orifice member 43, the pressure in the pressure chamber 25 gradually decreases without suddenly decreasing. The power element 35 detects a high air temperature in the passenger compartment when the air conditioning on the rear side is stopped, and the pressure in the temperature sensitive greenhouse is high. Therefore, the piston 23 is pushed by the diaphragm 38 and expands. It moves slowly in the valve opening direction and stops at the fully open position. As a result, even if the differential pressure across the expansion valve is large, a large flow rate of high-pressure refrigerant does not flow through the expansion valve all at once, so that no refrigerant flow noise is generated. Further, while the solenoid valve 39 is energized, the high-pressure refrigerant always leaks slightly to the downstream side of the expansion valve via the check valve.

  As a result, when high-temperature and high-pressure liquid refrigerant is supplied from the receiver 3 to the high-pressure refrigerant inlet 30 through the high-pressure pipe 32 of the internal heat exchanger 8, the liquid refrigerant passes through the gap between the valve seat 18 and the valve element 19. And flows out to the low-pressure refrigerant outlet 28. At this time, the refrigerant is adiabatically expanded to become a low-temperature / low-pressure gas-liquid mixed refrigerant, and is introduced into the rear evaporator 7 from the refrigerant inlet pipe 12. In addition, the arrow in a figure has shown the flow direction of the refrigerant | coolant. In the rear-side evaporator 7, the introduced refrigerant is evaporated by heat exchange with the air in the passenger compartment and flows out from the refrigerant outlet pipe 13. The refrigerant is introduced from the return low-pressure refrigerant inlet 29, flows out to the return low-pressure refrigerant outlet 31 through a plurality of low-pressure refrigerant passages, and is returned to the inlet of the compressor 1 through the return low-pressure pipe 33.

  If the operation is continued with the expansion valve fully opened, the air in the passenger compartment is eventually cooled and the temperature of the refrigerant returning from the rear evaporator 7 is lowered. When the temperature of the refrigerant decreases, the expansion valve 11 with a solenoid valve controls the flow rate of the refrigerant supplied to the rear evaporator 7 so that the refrigerant at the outlet of the rear evaporator 7 has a predetermined degree of superheat. .

  The power element 35 does not adopt a method of fixing the lower housing 37 to the body 16, but the outer peripheral portion of the power element 35 is formed by caulking the outer tube having a double tube structure of the main cylindrical portion 14. Is fixed to the body 16, the opening of the lower housing 37 can be enlarged, and thereby the space surrounded by the diaphragm 38 and the lower housing 37 is greatly communicated with the low-pressure refrigerant passage. . For this reason, when the refrigerant returned from the rear side evaporator 7 passes through the passage of the low-pressure refrigerant, the refrigerant is introduced into the lower housing 37 and the temperature thereof is detected by the power element 35. In the expansion valve 11 with a solenoid valve, the pressure of the refrigerant introduced from the rear evaporator 7 is not detected by the power element 35. This is because the effective pressure receiving diameter of the piston 23 (corresponding to the outer diameter of the O-ring 27) is the same as the effective pressure receiving diameter of the diaphragm 38, and the pressure of the refrigerant returned from the rear evaporator 7 thereby. Has been cancelled.

  Since the power element 35 moves up and down according to the temperature of the refrigerant detected by the pressure in the temperature sensitive greenhouse, the diaphragm 38 is displaced in the opening / closing direction of the valve body 19 according to the temperature. The displacement is transmitted to the shaft 22 and the valve body 19 via the piston 23. As a result, the lift of the valve body 19 changes, and the flow rate of the refrigerant supplied to the rear evaporator 7 is controlled.

  FIG. 5 is a cross-sectional view showing a non-energized state of the expansion valve with electromagnetic valve according to the second embodiment, and FIG. 6 is a cross-sectional view showing an energized state of the expansion valve with electromagnetic valve according to the second embodiment. . 5 and 6, the same components as those shown in FIGS. 2 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The expansion valve 61 with a solenoid valve according to the second embodiment is different from the expansion valve 11 with a solenoid valve according to the first embodiment in the structure of the check valve and the piston 23. That is, the check valve for introducing the high-pressure liquid refrigerant into the pressure chamber 25 is a ball valve using a ball as the valve body 62. In this check valve, the valve seat is a damaged valve seat, so that, similarly to the check valve of the reed valve structure of the expansion valve 11 with solenoid valve according to the first embodiment, even when fully closed, The high-pressure liquid refrigerant can be slightly leaked.

  Further, the piston 23 does not directly contact the diaphragm 38 of the power element 35, but a center disk 63 is interposed between the piston 23 and the diaphragm 38. The center disk 63 is made of a material having a low thermal conductivity, and the contact area with the piston 23 is reduced. As a result, even if the piston 23 is heated to a high temperature by introducing a high-temperature / high-pressure liquid refrigerant into the pressure chamber 25, the temperature is transferred to the diaphragm 38 to increase the pressure in the temperature sensing chamber, and the expansion valve due to the high pressure. This prevents the valve closing operation from being hindered.

  In such an expansion valve 61 with a solenoid valve, when the solenoid valve 39 is in a non-energized state, the solenoid valve 39 is closed as shown in FIG. As a result, the high-pressure liquid refrigerant slightly leaks through the check valve, is introduced into the communication passage 42 from the high-pressure introduction hole 44, and is introduced into the pressure chamber 25 through the orifice member 43. Therefore, the piston 23 is moved toward the power element 35 until the valve element 19 of the expansion valve is seated on the valve seat 18, and the expansion valve is fully closed while the air conditioning on the front side is performed. .

  When the solenoid valve 39 is energized, as shown in FIG. 6, the solenoid valve 39 is opened, and the refrigerant in the communication passage 42 and the pressure chamber 25 flows out downstream of the expansion valve. Since the orifice member 43 restricts the flow rate of the refrigerant flowing out of the pressure chamber 25, the pressure in the pressure chamber 25 gradually decreases, so that the piston 23 does not move suddenly in the valve opening direction of the expansion valve. Since the valve body 19 integrated with the shaft 22 fixed to the shaft does not move suddenly in the valve opening direction, a large amount of refrigerant does not flow, and generation of refrigerant flow noise is suppressed.

  FIG. 7 is a cross-sectional view showing a non-energized state of the expansion valve with solenoid valve according to the third embodiment, and FIG. 8 is a cross-sectional view showing a conductive state of the expansion valve with solenoid valve according to the third embodiment. . 7 and 8, the same components as those shown in FIGS. 5 and 6 are given the same reference numerals, and detailed descriptions thereof are omitted.

  The expansion valve 71 with a solenoid valve according to the third embodiment is different from the expansion valve 61 with a solenoid valve according to the second embodiment in that the valve structure of the check valve and the solenoid valve 39 is changed. Yes. That is, in this expansion valve 71 with a solenoid valve, the mounting hole 40 of the solenoid valve 39 is penetrated to the center hole into which the shaft guide 17 is press-fitted, and the plug 72 is disposed there. The plug 72 has an upper end fitted into the sleeve 46 and a lower end extending into the shaft guide 17.

  A cylindrical valve seat 41 is integrally formed on the plug 72 on a surface facing the plunger 48, and a valve body 49 that contacts and separates from the valve seat 41 is formed integrally with the plunger 48. The end surface of the plug 72 opposite to the plunger 48 side is recessed, and a valve body 73 of a check valve is accommodated therein. The valve body 73 is urged by a spring 74 in a direction to close a valve hole formed coaxially with the cylindrical valve seat 41. A shaft 75 is inserted into the valve hole. The upper part of the shaft 75 is fixed to the plunger 48, and the lower end surface lifts the valve body 73 so as to protrude from the valve hole of the check valve and open the check valve when the solenoid valve 39 is not energized. When the solenoid valve 39 is in the energized state, it is in a position to retract into the valve hole of the check valve and close the check valve. An intermediate portion of the valve hole has an opening that opens to a communication passage 42 that communicates with the pressure chamber 25 of the piston 23, and the opening is formed with a small diameter to form an orifice 76. The space around the tubular valve seat 41 formed in the plug 72 communicates with a communication passage 77 formed in the body 16 so as to communicate with the downstream side of the expansion valve. Therefore, the solenoid valve 39 is a three-way solenoid valve that switches the pressure chamber 25 to the upstream side of the expansion valve when not energized and switches the pressure chamber 25 to the downstream side of the expansion valve when energized. .

  In such an expansion valve 71 with a solenoid valve, when the solenoid valve 39 is in a non-energized state, the solenoid valve 39 is moved by a spring 50 biasing the plunger 48 with respect to the core 47 as shown in FIG. The valve body 49 is seated on the valve seat 41 so as to close the communication passage 77, and at the same time, the check valve is opened. As a result, the high-pressure liquid refrigerant enters the communication passage 42 via the check valve and the orifice 76 and is introduced into the pressure chamber 25. Therefore, the piston 23 is moved toward the power element 35 until the valve element 19 of the expansion valve is seated on the valve seat 18, and the refrigerant supplied to the front side expansion valve 4 during the front side air conditioning. The fully closed state of the expansion valve is maintained by the high pressure.

  When the solenoid valve 39 is energized, as shown in FIG. 8, the solenoid valve 39 is attracted to the core 47 by the plunger 48 so that the valve body 49 is lifted from the valve seat 41 and the check valve valve body 73 is Close the valve hole. Thereby, the refrigerant in the communication passage 42 and the pressure chamber 25 flows out downstream of the expansion valve. At this time, the orifice 76 restricts the flow rate of the refrigerant flowing out to the downstream side of the expansion valve, whereby the pressure in the pressure chamber 25 is gradually reduced, and therefore, the movement of the piston 23 to open the expansion valve can be delayed. A large flow rate of refrigerant does not flow all at once, and generation of refrigerant flow noise is suppressed.

It is a system diagram which shows the refrigerating cycle of the air conditioner for motor vehicles. It is sectional drawing which shows the non-energized state of the expansion valve with a solenoid valve which concerns on 1st Embodiment. It is the A section expanded sectional view of FIG. It is sectional drawing which shows the electricity supply state of the expansion valve with a solenoid valve which concerns on 1st Embodiment. It is sectional drawing which shows the non-energized state of the expansion valve with a solenoid valve which concerns on 2nd Embodiment. It is sectional drawing which shows the energization state of the expansion valve with a solenoid valve which concerns on 2nd Embodiment. It is sectional drawing which shows the non-energized state of the expansion valve with a solenoid valve which concerns on 3rd Embodiment. It is sectional drawing which shows the energization state of the expansion valve with a solenoid valve which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Receiver 4 Front side expansion valve 5 Front side evaporator 6 Electromagnetic valve expansion valve 7 Rear side evaporator 8 Internal heat exchanger 9, 10 Blower 11 Electromagnetic valve expansion valve 12 Refrigerant inlet piping 13 Refrigerant Outlet piping 14 Main cylindrical portion 15 Sub-cylindrical portion 16 Body 17 Shaft guide 18 Valve seat 19 Valve body 20 Spring 21 Spring receiving member 22 Shaft 23 Piston 24 O-ring 25 Pressure chamber 26 Annular groove 27 O-ring 28 Low pressure refrigerant outlet 29 Return low pressure Refrigerant inlet 30 High pressure refrigerant inlet 31 Return low pressure refrigerant outlet 32 High pressure piping 33 Return low pressure piping 34 Backup ring 35 Power element 36 Upper housing 37 Lower housing 38 Diaphragm 39 Electromagnetic valve 40 Mounting hole 41 Valve seat 42 Communication passage 43 Orifice member 44 High pressure introduction Hole 45 Over de piece 46 sleeve 47 core 48 plunger 49 the valve element 50 the spring 51 coils 52 yoke 61 solenoid valve with an expansion valve 62 valve element 63 centers the disc 71 with solenoid valve expansion valve 72 plug 73 valve 74 spring 75 shaft 76 orifice 77 communicating path

Claims (8)

In an expansion valve with a solenoid valve that integrates an expansion valve that adiabatically expands the refrigerant and a solenoid valve that can close the expansion valve,
A body having a main cylindrical part having both ends formed in a double-pipe structure and a pipe connection part extending in a direction perpendicular to the main cylindrical part;
A power element arranged to hermetically close the first outer tube on one end side of the main cylindrical portion;
A pressure chamber is fitted between the end face of the first inner pipe and is fitted to the first inner pipe on one end side of the main cylindrical portion in an airtight manner so as to be able to advance and retreat in the axial direction while being in contact with the power element. A formed piston;
The main cylindrical part is accommodated in a space formed in the axial direction between the first inner pipe on one end side and the second inner pipe on the other end side, and the high-pressure inlet of the pipe connecting part and the main cylindrical part A valve portion that opens and closes a passage between the second inner pipe and the power element and the piston;
The solenoid valve disposed in a communication path between the pressure chamber of the piston and the second inner pipe of the main cylindrical portion, and closed when not energized and opened when energized;
An expansion valve with a solenoid valve, comprising:   2. The expansion valve with an electromagnetic valve according to claim 1, wherein the power element is fixed to the body by caulking the first outer tube of the main cylindrical portion all around. 3.   2. The expansion valve with an electromagnetic valve according to claim 1, wherein the piston is integrated with a disk that transmits a displacement of a diaphragm of the power element to a valve body of the valve portion.   The disk that transmits the displacement of the diaphragm of the piston and the diaphragm of the power element to the valve body of the valve part is separate, and the disk is made of a material having low thermal conductivity. The expansion valve with a solenoid valve according to claim 1.   The high-pressure inlet that is disposed between the high-pressure inlet of the pipe connection portion and the communication passage on the pressure chamber side allows flow from the communication passage to the high-pressure inlet, and is fully introduced into the high-pressure inlet when fully closed. The expansion valve with a solenoid valve according to claim 1, further comprising a check valve configured to slightly leak the liquid refrigerant into the communication path.   The solenoid valve is formed integrally with the check valve, and is a three-way solenoid valve that opens the check valve when the valve is closed when not energized and closes the check valve when the valve is opened when energized. 6. The expansion valve with a solenoid valve according to claim 5,   2. The expansion valve with an electromagnetic valve according to claim 1, wherein the communication passage on the pressure chamber side has an orifice for delaying the advance / retreat operation of the piston.   2. The expansion valve with an electromagnetic valve according to claim 1, wherein the piston and the power element have equal effective pressure receiving diameters received by the piston and a diaphragm of the power element.

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