JP4923181B2 - Expansion valve - Google Patents

Description

  The present invention relates to an expansion valve, and more particularly to an expansion valve that controls the flow rate of refrigerant sent to an evaporator in accordance with the temperature and pressure of the refrigerant at the outlet of the evaporator in a refrigeration cycle of an automotive air conditioner.

  An automotive air conditioner generally includes a compressor driven by a vehicle engine, a condenser that condenses the refrigerant compressed by the compressor, a receiver that separates the condensed refrigerant into gas and liquid, and stores liquid refrigerant. An expansion valve that squeezes and expands the high-temperature and high-pressure liquid refrigerant to form a low-temperature and low-pressure mist refrigerant, and an evaporator that evaporates the mist refrigerant by exchanging heat with the air in the passenger compartment and returns it to the compressor. I have.

  As such an expansion valve, a temperature type expansion valve is known in which the flow rate of the refrigerant sent to the evaporator is controlled so that the refrigerant that has exited the evaporator has a predetermined degree of superheat. The temperature-type expansion valve has a valve section that adiabatically expands high-temperature and high-pressure liquid refrigerant to form a low-temperature and low-pressure mist refrigerant, and a power element that senses the temperature and pressure of the refrigerant that has exited the evaporator. The power element controls the valve lift of the valve part by transmitting the displacement of the diaphragm due to the pressure in the temperature sensing chamber changing according to the temperature and pressure of the refrigerant that has left the evaporator. .

This temperature type expansion valve has a low pressure return passage for allowing the refrigerant returning from the evaporator to the compressor to pass through in order for the power element to sense the temperature and pressure of the refrigerant that has exited the evaporator. In addition, it is formed through a substantially prismatic block constituting the body of the valve portion. Further, in order to function as a pipe joint, two bolt holes for fixing the pipe to be connected are formed through the body block. Such low-pressure return passages and bolt holes are holes formed in parallel through the block, so such holes are not machined, but such holes are hollow extruded. It is proposed to use a material formed by the above as a body (for example, see Patent Document 1). This eliminates the need to open at least such low pressure return passages and bolt holes, and machining costs are reduced. Since the holes are already opened as the body material, the material cost can be saved and the cost can be reduced. It is possible to make a cheap temperature type expansion valve.
JP-A-10-267470

  However, in the conventional expansion valve, the substantially prismatic block constituting the body of the valve portion is provided with a low-pressure refrigerant outlet connected to the refrigerant inlet of the evaporator, and a refrigerant inlet of the low-pressure return passage connected to the refrigerant outlet of the evaporator. Are arranged side by side, so that the direction of the expansion valve changes according to the position of the refrigerant inlet and the refrigerant outlet of the evaporator, and the high pressure and low pressure from the engine room connected to it by changing the direction of the expansion valve There is a problem that there is no degree of freedom in layout because it is necessary to bend the pipe. Further, in a conventional expansion valve having a body made of a substantially prismatic block in which a low pressure return passage and two bolt holes are formed by hollow extrusion processing, the end face of the hollow extruded material viewed from the extrusion direction is shown. Since the ratio of the area of the through hole formed by the hollow extrusion process to the area is small, there is a problem that the effect of saving the material cost by the hollow extrusion process of the body is small.

  The present invention has been made in view of the above points, and provides an expansion valve including a body that can freely change the direction of attachment when connecting to an evaporator and has a large effect of saving material costs. Objective.

  In the present invention, in order to solve the above problem, a power element that senses the temperature and pressure of the refrigerant that has exited the evaporator, and a valve that controls the flow rate of the refrigerant that is sent to the evaporator in accordance with the temperature and pressure sensed by the power element. A low-pressure refrigerant outlet connected to the evaporator refrigerant inlet is located inside a return low-pressure refrigerant inlet connected to the evaporator refrigerant outlet, and the low-pressure refrigerant outlet and the return low-pressure refrigerant. An expansion valve is provided that has a double-pipe structure that is substantially coaxial with the inlet.

  According to such an expansion valve, since the low-pressure refrigerant outlet and the return low-pressure refrigerant inlet connected to the evaporator have a double pipe structure, the refrigerant is sent to the high-pressure refrigerant inlet into which the high-pressure refrigerant is introduced and the compressor inlet. Since the return low-pressure refrigerant outlet can be attached to the evaporator in an arbitrarily oriented direction, the degree of freedom in the layout of the evaporator, the expansion valve, and the piping can be improved.

  The expansion valve of the present invention has a double pipe structure for connection to the evaporator, thereby simultaneously connecting the evaporator refrigerant inlet and the low pressure refrigerant outlet and connecting the evaporator refrigerant outlet and the return low pressure refrigerant inlet. In addition, since the connection to the evaporator is coaxial, the orientation of the part where the high-pressure piping and return low-pressure piping are connected can be freely changed when joining to the evaporator, improving the flexibility of layout There is an advantage that can be made.

  In addition, the body has a central hole in which the valve seat and the valve body are disposed and a low-pressure refrigerant passage disposed in the periphery thereof in the longitudinal direction so as to be formed in parallel. By forming, the material can be saved in large quantities.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a cross-sectional view showing an expansion valve according to the first embodiment in an attached state, FIG. 2 is a cross-sectional view taken along the line aa of FIG. 1, and FIG. 3 is an end face showing a hollow extruded material before processing the body. FIG. 4 is a perspective view of a body processed from a hollow extruded material, and FIG. 5 is a perspective sectional view of the body processed from a hollow extruded material.

  The expansion valve 10 according to the first embodiment has a configuration that is directly connected to the refrigerant inlet and the refrigerant outlet of the evaporator 11. The evaporator 11 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 evaporator 11 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 and integrated. Is formed.

  The expansion valve 10 includes a body 16 having an external shape such that a sub-cylindrical portion 15 extending downward in FIG. 1 is coupled to a main cylindrical portion 14 extending in the left-right direction in FIG. The main cylindrical portion 14 and the sub-cylindrical portion 15 have a double tube structure in their three end face shapes. As shown in FIG. 2, the main cylindrical portion 14 has a central hole 17 penetratingly formed at the center thereof, and four low-pressure refrigerant passages 18 are formed around the central hole 17.

  A shaft guide 19 and a ring-shaped valve seat 20 are fitted in the central hole 17 of the main cylindrical portion 14 and are fixed to the body 16 by caulking. A valve element 21 is arranged so as to be able to contact and separate from the valve seat 20. The valve body 21 is formed integrally with a shaft 22 that extends in the axial direction via the valve seat 20 and the shaft guide 19. A cylindrical collar member 23 is fitted to the end of the shaft 22 opposite to the side on which the valve body 21 is formed, and a sealing O-ring 24 is provided on the valve body 21 side. Has been placed. The collar member 23 has an outer diameter substantially equal to the inner diameter of the valve hole of the valve seat 20, thereby canceling the pressure of the refrigerant introduced into the expansion valve 10 and not being affected by high pressure fluctuations. ing.

  The valve body 21 is urged in the valve closing direction by a spring 25, and the spring 25 is received by a spring receiving member 26 that is press-fitted into an inner pipe of a double pipe formed on the evaporator 11 side of the main cylindrical portion 14. The load of the spring 25 is adjusted by the amount of press-fitting of the spring receiving member 26 into the inner tube. Here, a step is provided in the inner pipe in which the spring receiving member 26 is disposed, and the spring receiving member 26 is press-fitted into the expanded portion, and the tip of the spring receiving member 26 is formed in the inner pipe. The outer periphery is reduced in diameter so as not to contact the reduced diameter portion. As a result, an annular space surrounded by the spring receiving member 26 and the body 16 is formed at the tip of the direction in which the spring receiving member 26 is press-fitted. This is a body scraped off when the spring receiving member 26 is press-fitted. It constitutes a pocket for storing trash.

  An inner pipe having a double-pipe structure formed on the side where the spring receiving member 26 of the main cylindrical portion 14 is press-fitted constitutes a low-pressure refrigerant outlet 27 of the expansion valve 10 and is arranged outside the low-pressure refrigerant passage. Reference numeral 18 constitutes a return low-pressure refrigerant inlet 28 that receives the refrigerant that is communicated in an annular shape and returned from the evaporator 11. Here, the low-pressure refrigerant outlet 27 of the expansion valve 10 is fitted into the refrigerant inlet pipe 12 of the evaporator 11, and the fitting portion is sealed by an O-ring 29. Further, the return low-pressure refrigerant inlet 28 of the expansion valve 10 is fitted to the refrigerant outlet pipe 13 of the evaporator 11, and mechanically coupled to the evaporator 11 by caulking the tip part around the entire circumference. The fitting part is sealed by an O-ring 30.

  The space between the valve seat 20 and the collar member 23 in the central hole 17 of the main cylindrical portion 14 communicates with an inner pipe having a double pipe structure formed in the sub-cylindrical portion 15. 18 communicates with a space between the inner tube and the outer tube formed in the sub-cylindrical portion 15. Here, the inner tube of the sub-cylindrical portion 15 constitutes a high-pressure refrigerant inlet 31, and the space between the inner tube and the outer tube of the sub-cylindrical portion 15 is the refrigerant that has passed through the expansion valve 10 at the inlet of the compressor. A return low-pressure refrigerant outlet 32 to be returned is configured. Therefore, the high-pressure refrigerant inlet 31 of the expansion valve 10 is fitted with a high-pressure pipe 33 to which high-temperature and high-pressure liquid refrigerant from the receiver is supplied and is sealed by an O-ring 34. Further, the return low-pressure refrigerant outlet 32 of the expansion valve 10 is fitted into the return low-pressure pipe 35, and the entire circumference thereof is caulked so as to fix the back-up ring 36 fitted in the tip, thereby the return low-pressure pipe 35 and the machine. And a fitting portion with the return low-pressure pipe 35 is sealed by an O-ring 37. In this embodiment, the high-pressure pipe 33 and the return low-pressure pipe 35 connected to the sub-cylindrical portion 15 can be a double pipe, or can be an internal heat exchanger having a double pipe structure.

  As described above, the expansion valve 10 is configured to connect the two fluid passages at the same time by connecting the evaporator 11 with a coaxial double pipe structure by caulking the entire circumference of the outer pipe. In addition, since the connection with the evaporator 11 is coaxial, the body 16 can rotate around the concentric axes of the low-pressure refrigerant outlet 27 and the return low-pressure refrigerant inlet 28 before joining to the evaporator 11. The direction of the opening direction of the high-pressure refrigerant inlet 31 and the return low-pressure refrigerant outlet 32 into which the high-pressure pipe 33 and the return low-pressure pipe 35 are fitted can be freely changed. Alternatively, the expansion valve 10 can be coupled to the evaporator 11 in a posture that matches the direction of the high pressure pipe 33 and the return low pressure pipe 35 extending from the engine room.

  The opening end of the body 16 on the side opposite to the side connected to the evaporator 11 is sealed by caulking all around so as to lock the outer peripheral edge of the power element 38. The power element 38 includes a thick metal upper housing 39 and a lower housing 40, a diaphragm 41 made of a flexible thin metal plate welded together with an outer peripheral edge sandwiched therebetween, and an inner portion of the lower housing 40. And a center disk 42 disposed in the center. A space surrounded by the upper housing 39 and the diaphragm 41 constitutes a temperature-sensitive greenhouse, and is filled with refrigerant gas or the like. The center disk 42 has one surface in contact with the diaphragm 41 and the other surface in contact with the end surface of the collar member 23 fitted to the shaft 22 protruding from the body 16. Is transmitted to the valve body 21. The lower housing 40 has its open ends bent alternately inward and outward in the circumferential direction, the outer bent portion is used to prevent the sealing O-ring 43 from falling off, and the inner bent portion is the center disk 42. It is a stopper to prevent falling off.

  In the expansion valve 10 having the above configuration, when high-temperature and high-pressure liquid refrigerant is supplied from the receiver to the high-pressure refrigerant inlet 31 through the high-pressure pipe 33, the liquid refrigerant passes through the gap between the valve seat 20 and the valve body 21. And flows out to the low-pressure refrigerant outlet 27. At this time, the refrigerant is adiabatically expanded to become a low-temperature / low-pressure gas-liquid mixed refrigerant and is introduced into the evaporator 11 from the refrigerant inlet pipe 12. In addition, the arrow in a figure has shown the flow direction of the refrigerant | coolant. In the evaporator 11, 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 28, flows out to the return low-pressure refrigerant outlet 32 through the low-pressure refrigerant passage 18, and is returned to the compressor inlet via the return low-pressure pipe 35.

  Since the space surrounded by the diaphragm 41 and the lower housing 40 of the power element 38 communicates with the low-pressure refrigerant passage 18, when the refrigerant returned from the evaporator 11 passes through the low-pressure refrigerant passage 18, the refrigerant is introduced. The temperature and pressure are detected by the power element 38. Since the pressure in the sensation chamber rises and falls according to the detected temperature and pressure of the refrigerant, the diaphragm 41 is displaced in the opening / closing direction of the valve body 21 according to the temperature and pressure. The displacement is transmitted to the collar member 23 via the center disk 42 and further transmitted to the valve body 21 via the shaft 22. As a result, the lift of the valve body 21 changes, and the flow rate of the refrigerant supplied to the evaporator 11 is controlled. That is, the expansion valve 10 senses the temperature and pressure of the refrigerant exiting the evaporator 11 and controls the flow rate of the refrigerant supplied to the evaporator 11 so that the refrigerant maintains a predetermined degree of superheat.

  By the way, the body 16 of the expansion valve 10 is preferably formed by processing a hollow extruded material. The hollow extrusion molding material has an outer shape in which a cylindrical portion 44 and a belt-like portion 45 located on the side surface thereof are integrally formed as shown in FIG. 3 in an end surface viewed from the extrusion direction. The cylindrical portion 44 has a round hole 46 formed in the center, and four passages 47 are opened in parallel to the round hole 46 around the circular hole 46. This means that the area occupied by the hollow portion with respect to the end face of the hollow extrusion molding material viewed from the extrusion direction is very large, and the material can be greatly reduced.

  The body 16 is formed by cutting the hollow extruded material as described above. That is, the circular hole 46 of the cylindrical portion 44 formed so as to penetrate in the moving direction of the valve body 21 is expanded from both end surfaces using this as a lower hole, so that the shaft guide 19 and the valve seat 20 are fitted. A portion to be inserted, a portion into which the spring receiving member 26 is press-fitted, a portion into which the collar member 23 and the O-ring 24 are inserted, and the like are formed. The cylindrical portion 44 is formed into a double tube structure by forming an annular space concentric with the round hole 46 by cutting from both ends. The belt-like portion 45 is cut at both ends along the outer shape of the cylindrical portion 44, and the high-pressure refrigerant inlet 31 and the return low-pressure refrigerant outlet are cut by cutting in a direction substantially perpendicular to the axis of the round hole 46 with respect to the remaining portion. 32 is formed into a double tube structure. In this way, the body 16 having an overview as shown in FIG. 4 and an internal structure as shown in FIG. 5 is formed.

  In the expansion valve 10 according to the first embodiment, the body 16 is formed by machining a hollow extruded material, but the body 16 can also be formed by a die casting method. . In this case, a die that can be coupled / separated in the axial direction of a double tube structure in three directions is used, and a die-cast product having a cross-sectional structure as shown in FIG. Since the precision parts that determine the valve opening characteristics are the valve seat 20 and the valve body 21 incorporated in the body 16, the die-cast product is used as the body 16 without requiring any additional finishing process. It is possible.

  6 is a cross-sectional view showing the expansion valve according to the second embodiment in an attached state, FIG. 7 is a cross-sectional view taken along the line bb in FIG. 6, and FIG. 8 is a cross-sectional view taken along the line cc in FIG. 9 is an end view showing the hollow extruded material before processing the body. 6 to 9, the same or equivalent components as those shown in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Compared with the expansion valve 10 according to the first embodiment, the expansion valve 10a according to the second embodiment has an insertion direction of the high-pressure pipe 33 for introducing a high-pressure refrigerant, and a low-pressure refrigerant to the compressor. The difference is that the insertion direction of the return low-pressure pipe 35 to be returned is set at a right angle, and the shape of the hollow extruded material forming the body 16 is changed.

  First, the body 16 has a cross-sectional shape of the passage 47 formed in parallel with the round hole 46 as shown in FIG. 9, as shown in FIG. That is, in the hollow extrusion molding material of FIG. 3, the four passages 47 arranged around the round hole 46 are separated by three thin partition walls and a thick partition wall, whereas the hollow extrusion molding material of FIG. The thin partition walls are eliminated, and the position of the belt-like portion 45 formed on the side wall of the cylindrical portion 44 is moved 90 degrees clockwise from the position where the thick partition walls are located. The expansion valve 10a according to the second embodiment uses a body 16 formed by processing such a hollow extruded material.

  As shown in FIGS. 6 and 7, the high-pressure refrigerant inlet 31 is formed by being drilled from the side wall of the main cylindrical portion 14 toward the central hole 17. The high-pressure pipe 33 is connected to the high-pressure refrigerant inlet 31 by inserting the high-pressure pipe 33 together with the O-ring 34 into the high-pressure refrigerant inlet 31 and fixing the flanged pipe 48 to the body 16 by caulking.

  As shown in FIGS. 7 and 8, the return low-pressure refrigerant outlet 32 is formed by being drilled so as to communicate with the low-pressure refrigerant passage 18 from the belt-like portion 45. A return low-pressure pipe 35 is inserted into the return low-pressure refrigerant outlet 32 together with an O-ring 37, and the return low-pressure pipe 35 is connected to the return low-pressure refrigerant outlet 32 by fixing the flanged pipe 49 to the body 16 by caulking. .

  The expansion valve 10a having the above configuration operates substantially the same as the expansion valve 10 according to the first embodiment, except that the connection direction of the high pressure pipe 33 and the return low pressure pipe 35 is different. Description of the operation is omitted.

  10 is a cross-sectional view showing the expansion valve according to the third embodiment in an attached state, FIG. 11 is a cross-sectional view taken along the line dd in FIG. 10, and FIG. 12 is an end view showing the hollow extruded material before processing the body. FIG. 10 to 12, the same or equivalent components as those shown in FIGS. 1 to 9 are denoted by the same reference numerals, and detailed description thereof will be omitted.

  In the expansion valve 10b according to the third embodiment, compared with the expansion valves 10 and 10a according to the first and second embodiments, the refrigerant returning to the compressor becomes too hot when the refrigeration load is high. And a means for making the power element 38 less susceptible to the influence of the ambient temperature, and further, the body 16 has a large material cost saving effect due to the hollow extrusion process. Different.

  First, as shown in FIG. 12, the body 16 has a round hole 46 opened at the center of the cylindrical portion 44 as compared with the hollow extruded material shown in FIGS. 3 and 9. The inner diameter of is increased. As the inner diameter of the round hole 46 is increased, the volume to be hollowed out increases, and the cutting allowance when cutting a hole concentric with the round hole 46 can be reduced.

  By increasing the inner diameter of the round hole 46, the configuration for supporting the shaft 22 on the power element 38 side is changed. That is, the cylindrical body 50 is press-fitted into the open end of the round hole 46, and the tip of the cylindrical body 50 on the valve body 21 side is bent inward to prevent the O-ring 24 from falling off. The inner wall of the cylindrical body 50 serves as a guide for the collar member 23.

  A differential pressure valve 51 is disposed in an annular space formed on the evaporator 11 side of the body 16. The differential pressure valve 51 has a holder 52 fitted to an inner pipe constituting the low-pressure refrigerant outlet 27 to the evaporator 11. The holder 52 has a mounting hole 54 that communicates with a bypass passage 53 formed in the inner pipe and opens into the low-pressure refrigerant passage 18. A diaphragm 55 is disposed in the mounting hole 54, an outer periphery thereof is sandwiched between a holder 52 and a spring receiving member 56 press-fitted into the mounting hole 54, and an inner periphery thereof is a valve body 57 having a through hole at the center thereof and the valve body 57. It is clamped by the cylindrical member 58 fitted in the. The valve body 57 is biased upward in the figure by a spring 59 and closes the bypass passage 53 when the difference between the pressure of the low-pressure refrigerant outlet 27 and the pressure of the low-pressure refrigerant passage 18 is small.

  The opening end of the body 16 on the side opposite to the side to which the evaporator 11 is connected is closed by a power element 38. The power element 38 is fixed to the body 16 while being covered by a heat insulating cover 60. . As a result, the power element 38 is not directly exposed to the outside air, so that the power element 38 can be made less susceptible to changes in ambient temperature.

  The expansion valve 10b having the above configuration is suitable when the high pressure pipe 33 and the return low pressure pipe 35 connected thereto are internal heat exchangers having a double pipe configuration. That is, in the refrigeration cycle in which the internal heat exchanger is connected to the expansion valve 10b, heat is exchanged between the high-temperature and high-pressure refrigerant supplied from the receiver and the low-temperature and low-pressure refrigerant returning from the expansion valve 10b to the compressor. The refrigerant that has left the evaporator 11 and passed through the expansion valve 10b is further heated by the internal heat exchanger and sucked into the compressor. However, when the refrigeration load is high, the refrigerant sucked into the compressor becomes too high, and the temperature of the refrigerant discharged from the compressor may become too high. In such a case, the lubricating oil of the compressor is deteriorated and causes the burn-in of the compressor. Therefore, particularly when the refrigeration load is high, it is necessary to suppress the temperature of the refrigerant returning to the compressor from becoming too high. There is. The differential pressure valve 51 controls the temperature when the refrigeration load is high. When the refrigeration load is abnormally high and the flow rate of the refrigerant supplied to the evaporator 11 increases, the pressure loss of the evaporator 11 increases and the differential pressure across the evaporator 11 also increases. The differential pressure valve 51 senses such a differential pressure and opens the valve, and causes the low-temperature refrigerant passage 18 to flow out a low-temperature refrigerant passage with a very large amount of moisture immediately after adiabatic expansion through the bypass passage 53. Thereby, the temperature of the refrigerant entering the internal heat exchanger is lowered, and the refrigerant discharged from the compressor is prevented from becoming too high.

  FIG. 13: is sectional drawing which shows the expansion valve which concerns on 4th Embodiment in the attachment state. In FIG. 13, the same or equivalent components as those shown in FIGS. 1 to 11 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The expansion valve 10c according to the fourth embodiment is structurally almost the same as the expansion valve 10b according to the third embodiment, but the evaporator 11, the high-pressure pipe 33, and the return low-pressure The difference is that the connection with the pipe 35 is reversed. Therefore, in the expansion valve 10c, the inner pipe of the double pipe structure on the side opposite to the side where the power element 38 of the body 16 is attached becomes the high-pressure refrigerant inlet 31, and the outer pipe returns and becomes the low-pressure refrigerant outlet 32. ing. In addition, an inner pipe having a double pipe structure formed on the side of the body 16 serves as a low-pressure refrigerant outlet 27, and an outer pipe returns and serves as a low-pressure refrigerant inlet 28.

Thereby, this expansion valve 10c is the same in operation as the expansion valves 10, 10a, 10b of the first to third embodiments except that the refrigerant flow is reversed.
In the first to fourth embodiments described above, the expansion valves 10, 10 a, 10 b, and 10 c are directly connected to the refrigerant inlet pipe 12 and the refrigerant outlet pipe 13 having a double pipe structure formed integrally with the evaporator 11. Although the case where it couple | bonds was demonstrated, you may make it connect the connection with the evaporator 11 via a double pipe.

It is sectional drawing which shows the expansion valve which concerns on 1st Embodiment in an attachment state. FIG. 2 is a cross-sectional view taken along the line aa in FIG. 1. It is an end view which shows the hollow extrusion molding material before a process of a body. It is a perspective view of the body which processed the hollow extrusion molding material. It is a perspective sectional view of the body which processed the hollow extrusion molding material. It is sectional drawing which shows the expansion valve which concerns on 2nd Embodiment in an attachment state. It is bb arrow sectional drawing of FIG. It is cc arrow sectional drawing of FIG. It is an end view which shows the hollow extrusion molding material before a process of a body. It is sectional drawing which shows the expansion valve which concerns on 3rd Embodiment in an attachment state. It is dd arrow sectional drawing of FIG. It is an end view which shows the hollow extrusion molding material before a process of a body. It is sectional drawing which shows the expansion valve which concerns on 4th Embodiment in an attachment state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a, 10b, 10c Expansion valve 11 Evaporator 12 Refrigerant inlet piping 13 Refrigerant outlet piping 14 Main cylinder part 15 Subcylinder part 16 Body 17 Center hole 18 Low pressure refrigerant path 19 Shaft guide 20 Valve seat 21 Valve body 22 Shaft 23 Color member 24 O-ring 25 Spring 26 Spring receiving member 27 Low-pressure refrigerant outlet 28 Return low-pressure refrigerant inlet 29, 30 O-ring 31 High-pressure refrigerant inlet 32 Return low-pressure refrigerant outlet 33 High-pressure pipe 34 O-ring 35 Return low-pressure pipe 36 Backup ring 37 O-ring 38 Power Element 39 Upper housing 40 Lower housing 41 Diaphragm 42 Center disk 43 O-ring 44 Cylindrical part 45 Band-like part 46 Round hole 47 Passage 48, 49 Flange pipe 50 Cylindrical body 51 Differential pressure valve 52 Holder 53 Bypass passage 54 Mounting hole 55 Diaphragm 56 Spring receiving member 57 Valve body 58 Tubular member 59 Spring 60 Thermal insulation cover

Claims (10)

An expansion valve comprising: a power element that senses the temperature and pressure of the refrigerant that has exited the evaporator; and a valve unit that controls the flow rate of the refrigerant sent to the evaporator according to the temperature and pressure sensed by the power element.
The low-pressure refrigerant outlet connected to the refrigerant inlet of the evaporator is located inside the return low-pressure refrigerant inlet connected to the evaporator refrigerant outlet, and the low-pressure refrigerant outlet and the return low-pressure refrigerant inlet are double in a substantially coaxial arrangement. An expansion valve characterized by having a tube structure.   A high-pressure refrigerant inlet for introducing a high-pressure refrigerant and a return low-pressure refrigerant outlet for sending the refrigerant to the compressor inlet in a direction substantially perpendicular to the axis of the low-pressure refrigerant outlet and the return low-pressure refrigerant inlet; The expansion valve according to claim 1.   A main cylindrical portion and a sub-cylindrical portion projecting in a direction substantially orthogonal to the main cylindrical portion are provided, and the main cylindrical portion has one end of the first inner tube and the first outer tube. A double pipe structure, the other end has a double pipe structure of a second inner pipe and a second outer pipe, and the second outer pipe is closed by the power element, A valve seat and a valve body which is formed so as to penetrate in the longitudinal direction along an axis passing through the center of the pipe and the second inner pipe and which can be contacted and separated in the longitudinal direction with respect to the valve seat are accommodated. A central hole and at least one low-pressure refrigerant passage formed in parallel so as to surround the central hole, and the sub-cylindrical portion has a double tube structure of a third inner tube and a third outer tube. The third inner pipe communicates with the central hole, and the low pressure is between the third inner pipe and the third outer pipe. Expansion valve according to claim 2, characterized in that it is formed so as to communicate with the medium passage.   In the body, the first inner pipe of the main cylindrical part constitutes the low-pressure refrigerant outlet, the first outer pipe constitutes the return low-pressure refrigerant inlet, and the third inner pipe of the sub-cylindrical part is the The expansion valve according to claim 3, wherein a high-pressure refrigerant inlet is formed, and the third outer pipe is the return low-pressure refrigerant outlet.   In the body, the first inner pipe of the main cylindrical part constitutes the high-pressure refrigerant inlet, the first outer pipe constitutes the return low-pressure refrigerant outlet, and the third inner pipe of the sub-cylindrical part is the The expansion valve according to claim 3, wherein a low-pressure refrigerant outlet is formed, and the third outer pipe is the return low-pressure refrigerant inlet.   The body is formed by cutting the hollow extruded material in which the central hole and the low-pressure refrigerant passage are formed in parallel so as to penetrate in the longitudinal direction to form the main cylindrical portion and the sub-cylindrical portion. The expansion valve according to claim 3.   4. The expansion valve according to claim 3, wherein the body is formed by die casting the main cylindrical portion and the sub-cylindrical portion.   A main cylindrical portion and a sub-cylindrical portion projecting in a direction substantially perpendicular to the main cylindrical portion are provided, and the main cylindrical portion has a first inner portion whose one end constitutes the low-pressure refrigerant outlet. A double pipe structure of a first outer pipe constituting the pipe and the return low-pressure refrigerant inlet, the other end being closed by the second inner pipe and the power element And is formed so as to penetrate in the longitudinal direction along an axis passing through the centers of the first inner pipe and the second inner pipe, and is in contact with and away from the valve seat inside and the valve seat in the longitudinal direction. A central hole in which the flexible valve body is accommodated and at least one low-pressure refrigerant passage formed in parallel so as to surround the central hole are formed, and the side surface is formed to communicate with the central hole. The high-pressure refrigerant inlet is provided, and the sub-cylindrical part is the low-pressure refrigerant passage. Expansion valve according to claim 2, characterized in that it has the return low-pressure refrigerant outlet formed so as to communicate.   The body is formed by cutting the hollow extruded material in which the central hole and the low-pressure refrigerant passage are formed in parallel so as to penetrate in the longitudinal direction to form the main cylindrical portion and the sub-cylindrical portion. The expansion valve according to claim 8.   The expansion valve according to claim 8, wherein the body is formed by die casting the main cylindrical portion and the sub-cylindrical portion.

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