JP2010255945A - Expansion valve and internal heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expansion valve having reduced manufacturing cost and an internal heat exchanger including the expansion valve, in a refrigerant cycle for a vehicle air conditioner. <P>SOLUTION: The expansion valve 30 includes only a functional part without joints to reduce the manufacturing cost, and the outer diameter of a power element is set smaller than the outer diameter of an expansion valve body. In the internal heat exchanger 10, an expansion valve storage cylinder is constituted by low pressure outlet side collecting piping 13 to which low pressure piping 19 to an evaporator is connected and a cylindrical part 13a integrally formed by processing a plate material 15. The expansion valve 30 is inserted from the side of the low pressure outlet side collecting piping 13 to the expansion valve storage cylinder with the power element located at the front, and is stored and fixed in the expansion valve storage cylinder by the low pressure piping 19 connected to the low pressure outlet side collecting piping 13 so as to prevent the expansion valve 30 from coming off from there. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an expansion valve and an internal heat exchanger, and in particular, sends low-temperature / low-pressure refrigerant to an evaporator by expanding high-temperature / high-pressure refrigerant supplied from a condenser in a refrigeration cycle of a vehicle air conditioner. An expansion valve configured to control the flow rate of the refrigerant to be sent out in accordance with the state of the refrigerant at the outlet of the evaporator, and an interior in which such an expansion valve is incorporated and heat exchange is performed between the high-pressure side refrigerant and the low-pressure side refrigerant It relates to a heat exchanger.

  A vehicle air conditioner generally includes a compressor driven by a traveling engine of a vehicle, a condenser that condenses the refrigerant compressed by the compressor, a receiver that separates the condensed refrigerant into gas and liquid, and a high-temperature / high-pressure liquid. It has an expansion valve that squeezes and expands the refrigerant to form a low-temperature / low-pressure mist-like refrigerant, and an evaporator that evaporates the mist-like refrigerant by exchanging heat with the air in the passenger compartment and returns it to the compressor. The vehicle air conditioner uses an internal heat exchanger to further increase the coefficient of performance of the refrigeration cycle (see, for example, FIG. 1 of Patent Document 1). The internal heat exchanger is configured to exchange heat between the high-temperature and high-pressure liquid refrigerant sent from the receiver to the expansion valve and the low-temperature and low-pressure refrigerant returning from the evaporator to the compressor.

  As an expansion valve, a temperature type expansion valve that controls the flow rate of the refrigerant that is sent to the evaporator so that the refrigerant that has exited the evaporator has a predetermined degree of superheat is generally known (see, for example, FIG. 4 of Patent Document 1). This temperature type expansion valve has a block-shaped expansion valve body with a built-in valve portion, and a power element that controls the valve portion by sensing the temperature and pressure of the refrigerant returned from the evaporator. The expansion valve body includes a high pressure inlet to which high pressure piping is connected, a low pressure outlet to which low pressure piping is connected, a return inlet to which return piping from the evaporator is connected, and a return outlet to which return piping to the compressor is connected. It has the function of the joint part of piping.

  Here, the internal heat exchanger and the expansion valve are connected to each other by connecting the high-pressure outlet of the internal heat exchanger and the high-pressure inlet of the expansion valve, and the return inlet of the internal heat exchanger and the return outlet of the expansion valve by piping. Is configured.

JP 2005-226885 A

  However, in the above-described refrigeration cycle, an internal heat exchanger and an expansion valve composed of independent functional parts are simply connected, and the expansion valve is a block-shaped expansion valve that requires cutting. Since it has a main body, there existed a problem that the manufacturing cost of a vehicle air conditioner will become high.

  This invention is made | formed in view of such a point, and it aims at providing the internal heat exchanger which incorporated the expansion valve which reduced manufacturing cost, and such an expansion valve.

  In the present invention, in order to solve the above-described problem, an internal heat exchanger that performs heat exchange between the high-pressure side refrigerant and the low-pressure side refrigerant in the refrigeration cycle of the vehicle air conditioner is mounted. In the expansion valve that squeezes and expands the finished high-pressure side refrigerant, a cylindrical expansion valve body in which a valve body is housed, a high-pressure inlet is formed on the side, and a low-pressure outlet is formed on one end in the axial direction; A power element coupled to the other axial end of the expansion valve body, the outer diameter of the power element being smaller than the outer diameter of the expansion valve body, and a high pressure side of the internal heat exchanger. There is provided an expansion valve characterized in that it can be inserted into the expansion valve storage cylinder provided at the outlet from the power element.

  Also, a plurality of plate members are stacked to alternately form the first passage and the second passage, and between the high-pressure side refrigerant flowing through the first passage and the low-pressure side refrigerant flowing through the second passage. In the internal heat exchanger that performs heat exchange at the high pressure inlet side collecting pipe connected to one end side of the first passage, and in the direction in which the plate material is laminated on the other end side of the first passage An expansion valve housing cylinder, one end of which constitutes a low-pressure outlet side collecting pipe, the other end opens into the second passage, and a side portion communicates with the first passage; A return inlet side collecting pipe connected to the second passage on the other end side of one passage, and a return outlet side collecting pipe connected to the second passage on one end side of the first passage An expansion valve housed in the expansion valve housing cylinder, the expansion valve having a high pressure inlet at a side portion and a low end at an axial end. A cylindrical expansion valve body having outlets formed therein, and a power element coupled to the other axial end of the expansion valve body. In the expansion valve storage cylinder, the power element is Located at the other end of the valve storage cylinder and disposed in the second passage, the high-pressure inlet communicates with the first passage through a side portion of the expansion valve storage cylinder, and the low-pressure outlet is the An internal heat exchanger is provided that communicates with the low-pressure outlet side collecting pipe.

  According to such an expansion valve and an internal heat exchanger, the expansion valve is configured only by a basic function without a pipe joint function, and the joint function of the expansion valve is integrally formed on the side of the internal heat exchanger, Only the expansion valve is inserted.

  The expansion valve having the above configuration does not use a block-shaped expansion valve main body that also serves as a pipe joint, so that the production cost of the expansion valve can be reduced, and the expansion valve storage cylinder having the expansion valve joint function is provided inside. Since it is integrally formed on the side of the heat exchanger, the expansion valve can be easily mounted by simply inserting the expansion valve from the outside into the preformed internal heat exchanger, so that the assemblability can be improved. There is an advantage.

It is a top view which shows the external appearance of the internal heat exchanger which concerns on 1st Embodiment. FIG. 2 is a cross-sectional view taken along line aa in FIG. 1. It is sectional drawing which shows an expansion valve and its attachment state. It is sectional drawing which shows the 1st modification of the internal heat exchanger which concerns on 1st Embodiment. It is sectional drawing which shows the 2nd modification of the internal heat exchanger which concerns on 1st Embodiment. It is a figure which shows the external appearance of the internal heat exchanger which concerns on 2nd Embodiment. It is bb arrow sectional drawing of FIG. It is sectional drawing which shows the external appearance of the internal heat exchanger which concerns on 3rd Embodiment. It is sectional drawing which shows the external appearance of the internal heat exchanger which concerns on 4th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, taking as an example a case where the present invention is applied to a refrigeration cycle having an internal heat exchanger.
1 is a plan view showing an external appearance of an internal heat exchanger according to the first embodiment, FIG. 2 is a cross-sectional view taken along the line aa of FIG. 1, and FIG. 3 is a cross-sectional view showing an expansion valve and a mounted state thereof. is there. In addition, the arrow in a figure has shown the flow of the refrigerant | coolant.

  In the internal heat exchanger 10 according to the first embodiment, as shown in FIGS. 1 and 2, a high-pressure inlet side collecting pipe 11 and a return outlet side collecting pipe 12 are arranged adjacent to one end side of one surface. The low pressure outlet side collecting pipe 13 and the return inlet side collecting pipe 14 are arranged adjacent to each other on the back surface on the other end side of this surface. The internal heat exchanger 10 alternately stacks the first passages 16 through which the high-pressure refrigerant flows and the second passages 17 through which the low-pressure refrigerant flows by laminating a plurality of drawn plate materials 15 and joining them together. Is formed. The joining of the plate members 15 is performed by brazing in a vacuum furnace in a nitrogen atmosphere, for example.

  The first passage 16 has a high pressure inlet side collecting pipe 11 joined to one end side thereof, and a low pressure outlet side collecting pipe 13 joined to the other end side thereof. A high-pressure pipe 18 from the receiver is connected to the high-pressure inlet side collective pipe 11, and a low-pressure pipe 19 to the evaporator is connected to the low-pressure outlet side collective pipe 13. As a result, the refrigerant introduced into the high-pressure inlet-side collecting pipe 11 is distributed and flows through the plurality of first passages 16, and the refrigerant that has passed through the first passages 16 is collected into the low-pressure outlet side. It will flow into the collecting pipe 13.

  The second passage 17 has a return outlet side collecting pipe 12 joined to one end side thereof, and a return inlet side collecting pipe 14 joined to the other end side thereof. A return low pressure pipe 20 from the evaporator is connected to the return outlet side collective pipe 12, and a return low pressure pipe 21 to the compressor is connected to the return inlet side collective pipe 14. Thus, the refrigerant returned from the evaporator to the return inlet side collecting pipe 14 is distributed and flows through the plurality of second passages 17, and the refrigerant that has passed through each of the second passages 17 is collected and returned. It will flow into the outlet side collecting pipe 12.

  The low-pressure outlet side collecting pipe 13 constitutes an expansion valve housing cylinder 22 together with a cylindrical portion 13a formed coaxially on the back side. The cylindrical portion 13a is integrally formed by processing the plate material 15 that partitions the high pressure and the low pressure. An expansion valve 30 is stored in the expansion valve storage cylinder 22.

  As shown in FIG. 3, this expansion valve 30 has a cylindrical expansion valve main body 31 having a cylindrical appearance, and a high-pressure inlet 32 for introducing a high-pressure refrigerant is formed on the side surface thereof. Has a low-pressure outlet 33 through which low-pressure refrigerant is led out. The expansion valve body 31 has a passage in which a high pressure inlet 32 and a low pressure outlet 33 communicate with each other, and a metal valve seat member 34 is fixed to the passage. The valve seat member 34 is formed with a round recess in the surface on the low pressure outlet 33 side to form a valve hole and a valve seat, and the valve hole communicates with the low pressure outlet 33 via a valve shaft holder 35. . The valve shaft holder 35 has, for example, a support portion protruding from three sides toward the center and a refrigerant passage formed between the support portions, so that the refrigerant in the valve hole flows to the low-pressure outlet 33 through the refrigerant passage. It has become.

  On the low pressure outlet 33 side of the valve seat member 34, a valve body 36 that opens and closes the valve hole is arranged in a state of being biased in the valve closing direction by a spring 37. The spring 37 is received by a cylindrical adjustment member 38 that is press-fitted into the low-pressure outlet 33, and the load is adjusted by the amount of press-fitting of the adjustment member 38 into the low-pressure outlet 33, and the degree of superheat of the expansion valve 30 The set value has been adjusted.

  The valve body 36 is formed integrally with the valve shaft 39 and is supported by the valve shaft holder 35 of the valve seat member 34 so as to be movable forward and backward. A collar 40 is fitted to the end of the valve shaft 39 opposite to the valve body 36. The collar 40 supports the end portion of the valve shaft 39 by the expansion valve body 31 so as to be movable back and forth in the valve opening / closing direction, and the high-pressure refrigerant introduced into the high-pressure inlet 32 is between the expansion valve body 31 and the collar 40. The O-ring 41 that is installed so as not to leak into the second passage 17 is pressed through the clearance.

  The upper part of the figure of the expansion valve main body 31 is formed with a cylindrical projecting portion so as to form a mounting portion for the power element 42. The power element 42 includes a thick metal upper housing 43 and a lower housing 44, and a diaphragm 45 made of a flexible thin metal plate disposed so as to partition a space surrounded by the thick housing. The space surrounded by the upper housing 43 and the diaphragm 45 constitutes a greenhouse, and is filled with gas having characteristics similar to those of a refrigerant. The lower housing 44 has a cylindrical fitting portion that is fitted to the cylindrical protrusion of the expansion valve main body 31 and a pressure equalizing hole 46. The pressure equalizing hole 46 communicates the space surrounded by the lower housing 44 with the second passage 17 so that the diaphragm 45 can sense the temperature and pressure of the refrigerant flowing through the second passage 17. It has become. The diaphragm 45 is in contact with the end face of the collar 40 fitted to the valve shaft 39, and the displacement of the diaphragm 45 is transmitted to the valve body 36.

  The expansion valve main body 31 is provided with grooves for fitting O-rings 47 and 48 at both ends in the axial direction thereof, so that high-pressure side refrigerant can be gathered from the entire circumference and introduced into the high-pressure inlet 32 at an intermediate outer periphery. It has a reduced diameter portion 31a.

  The outer diameter of the power element 42, that is, the outer diameter of the upper housing 43 is formed smaller than the outer diameter of the expansion valve main body 31. Moreover, the outer diameter of the expansion valve body 31 is formed to be equal to or smaller than the seal diameter, which is the inner diameter of the low-pressure outlet side collecting pipe 13 and the cylindrical portion 13a. Thereby, the expansion valve 30 can be inserted into the low pressure outlet side collecting pipe 13 and the cylindrical portion 13a from the power element 42 side.

  A connecting plate 49 is disposed on the open end side of the high pressure inlet side collecting pipe 11 and the return outlet side collecting pipe 12 and is connected to the connecting plate 50 fitted to the high pressure pipe 18 and the return low pressure pipe 21 by, for example, bolting. It is like that. Similarly, a connecting plate 51 is arranged on the open end side of the low pressure outlet side collecting pipe 13 and the return inlet side collecting pipe 14, and the connecting plate 52 fitted to the low pressure pipe 19 and the returning low pressure pipe 20 is tightened with, for example, a bolt. It is designed to be connected. In addition, the connection plate 49 attached to the high-pressure inlet side collecting pipe 11 and the return outlet side collecting pipe 12 is omitted in FIG.

  2, the internal heat exchanger 10 is integrally formed without the high pressure pipe 18, the return low pressure pipe 21 and the connection plate 50, the low pressure pipe 19, the return low pressure pipe 20 and the connection plate 52, and the expansion valve 30. Has been. In this state, the high-pressure pipe 18 and the return low-pressure pipe 21 are respectively inserted into the high-pressure inlet side collecting pipe 11 and the return outlet side collecting pipe 12 and connected by the connecting plates 49 and 50. In the expansion valve storage cylinder 22, the expansion valve 30 is inserted first, then the low pressure pipe 19 is inserted, the return low pressure pipe 20 is inserted in the return inlet side collective pipe 14, and the connecting plates 51, 52 It is connected by. The expansion valve 30 is housed and held in the low-pressure outlet-side collecting pipe 13 by inserting the low-pressure pipe 19 into the low-pressure outlet-side collecting pipe 13 and being connected to each other. it can.

  Next, operations of the internal heat exchanger 10 and the expansion valve 30 will be described. First, when the vehicle air conditioner is stopped, the expansion valve 30 is condensed with the gas sealed in the temperature-sensitive room of the power element 42, and the pressure is lowered. Therefore, as shown in FIG. 45 is displaced inward (upward in the figure), and the displacement is transmitted to the valve body 36 via the valve shaft 39, and the expansion valve 30 is in a fully closed state.

  Here, when the vehicle air conditioner is activated, the refrigerant is sucked by the compressor, so that the pressure in the return low-pressure pipe 21 and the second passage 17 of the internal heat exchanger 10 communicating with the return low-pressure pipe 21 is reduced. As a result, the diaphragm 45 is displaced toward the valve body 36 to lift the valve body 36. On the other hand, the refrigerant compressed by the compressor is condensed by the condenser and the liquid refrigerant separated by the receiver is introduced into the internal heat exchanger 10 through the high-pressure pipe 18. This refrigerant is introduced into the expansion valve housing cylinder 22 through the first passage 16 of the internal heat exchanger 10 and supplied to the high-pressure inlet 32 of the expansion valve 30. The refrigerant at the high pressure inlet 32 flows out to the low pressure outlet 33 through the gap between the lifted valve body 36 and the valve seat member 34. When passing through the expansion valve 30, the refrigerant is expanded to become a low-temperature / low-pressure gas-liquid mixed refrigerant. The refrigerant is supplied to the evaporator via the low-pressure pipe 19 and evaporated by heat exchange with warm air in the passenger compartment. The evaporated refrigerant is introduced into the return inlet side collecting pipe 14 of the internal heat exchanger 10 through the return low pressure pipe 20. The refrigerant introduced into the internal heat exchanger 10 flows out to the return outlet side collecting pipe 12 through the second passage 17. At this time, heat exchange is performed between the liquid refrigerant flowing through the first passage 16 and the gas refrigerant flowing through the second passage 17, and the liquid refrigerant introduced into the expansion valve 30 is further subcooled and returns to the compressor. The gas refrigerant can be further heated to improve the coefficient of performance of the refrigeration cycle.

  In the expansion valve 30, the space surrounded by the diaphragm 45 and the lower housing 44 of the power element 42 communicates with the second passage 17 through the pressure equalizing hole 46, so that the refrigerant returned from the evaporator is the second When passing through the passage 17, the refrigerant is introduced and the temperature and pressure are detected by the power element 42. In the initial stage of starting the vehicle air conditioner, the temperature of the refrigerant returning from the evaporator is high due to heat exchange with the high-temperature air in the passenger compartment, and the power element 42 senses the temperature and Pressure increases. Thereby, the diaphragm 45 is displaced in the direction of the valve body 36, and the displacement is transmitted to the valve body 36 through the collar 40 and the valve shaft 39, so that the expansion valve 30 is almost fully opened.

  Eventually, when the temperature of the refrigerant returning from the evaporator decreases, the pressure in the sensation greenhouse decreases, and accordingly, the diaphragm 45 is displaced in the direction opposite to the side where the valve body 36 is located and expands. The valve 30 operates in the valve closing direction to control the flow rate of the refrigerant passing therethrough. At this time, the expansion valve 30 controls the flow rate of the refrigerant supplied to the evaporator so that the refrigerant at the outlet of the evaporator maintains a predetermined degree of superheat. As a result, the overheated refrigerant always returns to the compressor, so that the compressor can be operated efficiently.

  4 is a cross-sectional view showing a first modification of the internal heat exchanger according to the first embodiment, and FIG. 5 is a cross-section showing a second modification of the internal heat exchanger according to the first embodiment. FIG. 4 and 5, the same or equivalent components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The first modification and the second modification of the internal heat exchanger according to the first embodiment are the same as those in the internal heat exchanger according to the first embodiment shown in FIGS. The low-pressure pipe 19 has an outer diameter substantially equal to the outer diameter of the expansion valve main body 31 of the expansion valve 30 and the inner diameter of the low-pressure outlet side collective pipe 13, whereas the low-pressure pipe 19 is narrowed. Yes.

  Thus, when it is desired to use a pipe that is thinner than the expansion valve body 31 of the expansion valve 30 as the low-pressure pipe 19, in the first modification, at the inlet of the low-pressure outlet side collective pipe 13 that receives the low-pressure pipe 19, An adapter 53 that converts the size of the diameter and an O-ring 54 for sealing are arranged.

  On the other hand, in the second modification, the expansion valve body 31 of the expansion valve 30 is deformed so that the inner diameter of the low-pressure outlet 33 is substantially equal to the outer diameter of the thin low-pressure pipe 19, and the low-pressure pipe 33 is connected to the low-pressure outlet 33 of the expansion valve 30. 19 is connected directly. In this case, it can be carried out substantially without adding new members.

  FIG. 6 is a view showing the appearance of the internal heat exchanger according to the second embodiment, and FIG. 7 is a cross-sectional view taken along the line bb of FIG. 6 and 7, the same or equivalent components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The internal heat exchanger 10 according to the second embodiment is formed in a shape having an elongated appearance, and its internal structure is of a type different from that of the first embodiment. That is, the internal heat exchanger 10 is configured such that a pressure vessel 61 formed by laminating and joining a plurality of drawn plate members 15 is housed in a case 62 and covered with a case cover 63. The pressure vessel 61 has a configuration in which a plurality of first passages 16 are formed to be spaced apart in parallel. The space between the pressure vessel 61 and the case 62 and the case cover 63 and the pressure vessel 61 are adjacent to each other. A space formed between the first passages 16 constitutes a second passage 17. Accordingly, the return inlet side collective pipe 14 to which the return low pressure pipe 20 is connected is joined only to the case 62, and the return outlet side collective pipe 12 to which the return low pressure pipe 21 is connected is joined only to the case cover 63. . The high pressure inlet side collective pipe 11 to which the high pressure pipe 18 is connected is joined to the case cover 63 and the pressure vessel 61 so as to penetrate the case cover 63 and communicate with the inside of the pressure vessel 61. The low pressure outlet side collecting pipe 13 passes through the case 62 and the pressure vessel 61 and is joined thereto.

  In this embodiment, the low pressure outlet side collecting pipe 13 constitutes the expansion valve housing cylinder 22. The low-pressure outlet side collecting pipe 13 has a tip that opens to the second passage 17, and a hole that communicates with the reduced diameter portion 31 a of the expansion valve body 31 is formed on the side surface. The tip of the low pressure outlet side collecting pipe 13 on the second passage 17 side is bent inward to serve as a stopper for the expansion valve main body 31 when the expansion valve 30 is inserted into the low pressure outlet side collecting pipe 13. Of course, the inner diameter of the tip of the stopper is made larger than the outermost diameter of the upper housing 43 constituting the power element 42 so as not to hinder communication between the second passage 17 and the inside of the lower housing 44. I am doing so.

  Also in this internal heat exchanger 10, the expansion valve 30 is inserted into the low pressure outlet side collecting pipe 13 to which the low pressure pipe 19 to the evaporator is connected, and then the low pressure pipe 19 is connected to the low pressure outlet side collecting pipe 13. Is housed and held in the low-pressure outlet side collecting pipe 13. The expansion valve 30 housed in the low pressure outlet side collecting pipe 13 has its power element 42 located in the second passage 17 through which the low pressure refrigerant returning from the evaporator flows, and the high pressure inlet 32 in the pressure vessel 61. It arrange | positions so that the one channel | path 16 may be connected.

  Further, the operation of the refrigeration cycle having the internal heat exchanger 10 incorporating the expansion valve 30 is the same as the operation described with respect to the first embodiment, and therefore the description thereof is omitted here.

  FIG. 8 is a cross-sectional view showing the appearance of the internal heat exchanger according to the third embodiment. In FIG. 8, the same or equivalent components as those shown in FIGS. 1 to 7 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The internal heat exchanger 10 according to the third embodiment is configured as a double tube type, whereas the internal heat exchanger 10 according to the first and second embodiments is configured as a stacked type. The internal heat exchanger 10 has an outer tube 71 and an inner tube 72 arranged coaxially, and a passage between the outer tube 71 and the inner tube 72 is defined as a first passage 16 through which a high-pressure refrigerant flows. The internal passage is a second passage 17 through which low-pressure refrigerant flows. The inner tube 72 is composed of a heat transfer tube having smooth tube portions at both ends and a central portion having a corrugated spiral structure. At the end of the internal heat exchanger 10 on the evaporator side, the outer tube 71 is positioned outwardly from the end surface where the inner tube 72 terminates so that the inner diameter is substantially equal to the inner diameter of the inner tube 72. The low-pressure outlet pipe 73 is integrally formed by drawing. The low pressure outlet pipe 73 of the outer pipe 71 and the end 72 a of the inner pipe 72 constitute an expansion valve storage cylinder 22 for storing the expansion valve 30. Further, in the vicinity where the power element 42 of the expansion valve 30 is located, a part of the outer tube 71 in the circumferential direction is processed into a shape that follows the outer surface of the inner tube 72 so as to contact each other. The outer pipe 71, the inner pipe 72, and the return inlet pipe 74 are joined by brazing or the like through the pipe 71 and the inner pipe 72. The return inlet pipe 74 is formed so as to be bent at a right angle from the joint and to be parallel to the central axis of the low pressure outlet pipe 73. A connecting plate 52 is installed at the tip of the return inlet pipe 74 together with the tip of the low pressure outlet pipe 73.

  In this internal heat exchanger 10, the low pressure outlet pipe 73 is opened before the low pressure pipe 19 and the return low pressure pipe 20 are connected. Therefore, the expansion valve 30 is inserted from the opening, and the expansion valve storage cylinder 22 is inserted. Store in. The expansion valve 30 is accommodated in the expansion valve housing by inserting the low-pressure pipe 19 into the low-pressure outlet pipe 73, inserting the low-pressure pipe 20 back into the return inlet pipe 74, and connecting the connecting plates 51 and 52 by bolting, for example. Since it is housed and held in the tube 22, assemblability can be improved.

  In FIG. 8, only the end portion on the evaporator side of the internal heat exchanger 10 having a double-pipe structure is shown. However, the first passage 16 and the second passage 17 also branch at the opposite end portion. Thus, the high pressure pipe from the receiver and the return low pressure pipe to the compressor are connected.

  Further, the operation of the refrigeration cycle having the internal heat exchanger 10 incorporating the expansion valve 30 is the same as the operation described with respect to the first embodiment, and therefore the description thereof is omitted here.

  FIG. 9 is a cross-sectional view showing the appearance of the internal heat exchanger according to the fourth embodiment. In FIG. 9, the same or equivalent components as those shown in FIGS. 1 to 8 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The internal heat exchanger 10 according to the fourth embodiment is of a type having a double pipe structure, and the low pressure pipe 19 and the return low pressure pipe 20 connected to the end portion on the evaporator side are internally heat exchanged. It has the structure which can be connected in the direction orthogonal to the axis line of the vessel 10. According to the internal heat exchanger 10, the low pressure outlet pipe 73 is joined to the side surface near the tip of the outer pipe 71. In the vicinity of the power element 42 of the expansion valve 30, a part of the outer tube 71 in the circumferential direction is processed into a shape that follows the outer surface of the inner tube 72 so as to contact each other, and the outer tube 71 is in contact with the contact portion. The outer pipe 71, the inner pipe 72, and the return inlet pipe 74 are joined by brazing or the like through the inner pipe 72.

  The end 71 a of the outer tube 71 and the end 72 a of the inner tube 72 constitute an expansion valve storage cylinder 22 for storing the expansion valve 30. In this embodiment, the expansion valve storage portions of the end portion 71a of the outer tube 71 and the end portion 72a of the inner tube 72 are not processed except that a communication hole is formed in the joint portion of the low-pressure outlet pipe 73. Therefore, the diameter of the sealing surface of the end portion 72 a of the inner tube 72 with the O-ring 47 is smaller than that of the sealing surface of the end portion 71 a of the outer tube 71 with the O-ring 48. Therefore, the expansion valve body 31 of the expansion valve 30 is formed such that the outer diameter of the portion surrounding the O-ring 47 is smaller than the outer diameter of the portion surrounding the O-ring 48, and the outer diameter of the power element 42 is smaller than that. Is made even smaller. In addition, the expansion valve body 31 of the expansion valve 30 has a communication hole formed at the position of the low pressure outlet 33 corresponding to the communication hole formed in the joint portion of the low pressure outlet pipe 73. Further, in the expansion valve 30 of this embodiment, a temperature sensing cylinder 76 is connected to a temperature sensing chamber of the power element 42 via a capillary tube 75. The temperature sensing cylinder 76 is installed in the vicinity of the outlet of the second passage 17, and senses the temperature of the refrigerant leaving the internal heat exchanger 10 and going to the compressor.

  The end of the internal heat exchanger 10 opposite to the side on which the expansion valve 30 is housed closes the first passage 16 by joining the end of the outer pipe 71 and the inner pipe 72. A high-pressure inlet pipe 77 is joined to the side surface of the first passage 16 near the closed portion, and high-pressure refrigerant from the receiver is introduced here. The return outlet pipe 78 to which the return low pressure pipe 21 to the compressor is connected is configured by extending the inner pipe 72 from the end of the outer pipe 71.

  The expansion valve 30 is inserted from the opening end of the end portion 71a of the outer pipe 71 constituting the expansion valve housing cylinder 22, and the opening end is plugged with a plug 79, and the opening end of the end portion 71a is further crimped. The plug 79 is prevented from coming out of the outer tube 71. The plug 79 is provided with an O-ring 80 and is sealed so that refrigerant leakage from the end 71a to the outside does not occur.

  The operation of the refrigeration cycle having the internal heat exchanger 10 incorporating the expansion valve 30 is the same as the operation described with respect to the first embodiment, and therefore the description thereof is omitted here.

DESCRIPTION OF SYMBOLS 10 Internal heat exchanger 11 High pressure inlet side collective piping 12 Return outlet side collective piping 13 Low pressure outlet side collective piping 13a Cylindrical part 14 Return inlet side collective piping 15 Board | plate material 16 1st channel | path 17 2nd channel | path 18 High pressure piping 19 Low pressure Piping 20 Return low pressure piping 21 Return low pressure piping 22 Expansion valve storage cylinder 30 Expansion valve 31 Expansion valve main body 31a Reduced diameter portion 32 High pressure inlet 33 Low pressure outlet 34 Valve seat member 35 Valve shaft holder 36 Valve body 37 Spring 38 Adjustment member 39 Valve shaft 40 Collar 41 O-ring 42 Power element 43 Upper housing 44 Lower housing 45 Diaphragm 46 Pressure equalizing hole 47, 48 O-ring 49, 50, 51, 52 Connecting plate 53 Adapter 54 O-ring 61 Pressure vessel 62 Case 63 Case cover 71 Outer tube 71a end 72 inner pipe 72a end 73 Low pressure outlet piping 74 Return inlet piping 75 Capillary tube 76 Temperature sensing tube 77 High pressure inlet piping 78 Return outlet piping 79 Plug 80 O-ring

Claims (11)

An expansion valve that is mounted on an internal heat exchanger that exchanges heat between a high-pressure refrigerant and a low-pressure refrigerant in a refrigeration cycle of a vehicle air conditioner, and expands and expands the high-pressure refrigerant that has undergone heat exchange. In
A tubular expansion valve body in which a valve body is housed, a high pressure inlet is formed on the side, and a low pressure outlet is formed at one end in the axial direction;
A power element coupled to the other axial end of the expansion valve body,
The outer diameter of the power element is made smaller than the outer diameter of the expansion valve main body so that the power element can be inserted into the expansion valve storage cylinder provided at the outlet on the high pressure side of the internal heat exchanger. Features an expansion valve.   2. The expansion according to claim 1, wherein the expansion valve main body has an outer diameter at least at an end opposite to a side to which the power element is coupled, equal to or smaller than a seal diameter of the expansion valve housing cylinder. valve.   The expansion valve main body has a circumferentially provided groove for fitting an O-ring at both ends in the axial direction, and has a reduced diameter portion in the middle so that a high-pressure side refrigerant can be introduced into the high-pressure inlet from the entire circumference. The expansion valve according to claim 1. A plurality of plate members are stacked to alternately form the first passage and the second passage, and heat is generated between the high-pressure side refrigerant flowing through the first passage and the low-pressure side refrigerant flowing through the second passage. In the internal heat exchanger that performs the exchange,
A high-pressure inlet-side collecting pipe connected to one end of the first passage;
Arranged in the direction in which the plate members are laminated on the other end side of the first passage, one end constitutes a low-pressure outlet side collecting pipe, the other end opens to the second passage, and the side portion An expansion valve storage cylinder formed to communicate with the first passage;
A return inlet side collecting pipe connected to the second passage on the other end side of the first passage;
A return outlet side collecting pipe connected to the second passage on one end side of the first passage;
An expansion valve housed in the expansion valve housing tube;
With
The expansion valve has a cylindrical expansion valve body having a high pressure inlet at a side and a low pressure outlet at one end in the axial direction, and a power element coupled to the other axial end of the expansion valve body. In the expansion valve storage cylinder, the power element is located at the other end of the expansion valve storage cylinder and disposed in the second passage, and the high pressure inlet is a side portion of the expansion valve storage cylinder. An internal heat exchanger, wherein the low pressure outlet communicates with the low pressure outlet side collecting pipe through the first passage. A plurality of plate members are stacked to alternately form the first passage and the second passage, and heat is generated between the high-pressure side refrigerant flowing through the first passage and the low-pressure side refrigerant flowing through the second passage. In the internal heat exchanger that performs the exchange,
A pressure vessel in which the plate members are stacked and a plurality of the first passages are separated and formed in parallel;
A case for accommodating the pressure vessel and forming the second passage with the pressure vessel;
A high-pressure inlet side collecting pipe connected to one end side of the pressure vessel via the case;
The other end of the pressure vessel is arranged in the direction in which the plate members are laminated, one end constitutes a low-pressure outlet side collecting pipe extending outside through the case, and the other end is opened in the case And an expansion valve storage cylinder formed such that the side part communicates with the pressure vessel;
A return inlet side collecting pipe connected to communicate with the case on the other end side of the pressure vessel;
A return outlet side collecting pipe connected to communicate with the case at one end side of the pressure vessel;
An expansion valve housed in the expansion valve housing tube;
With
The expansion valve has a cylindrical expansion valve body having a high pressure inlet at a side and a low pressure outlet at one end in the axial direction, and a power element coupled to the other axial end of the expansion valve body. In the expansion valve storage cylinder, the power element is located at the other end of the expansion valve storage cylinder and disposed in the second passage, and the high pressure inlet is a side portion of the expansion valve storage cylinder. An internal heat exchanger, wherein the low pressure outlet communicates with the low pressure outlet side collecting pipe through the first passage. An inner tube is coaxially arranged in the outer tube to form a first passage and a second passage, and a high-pressure side refrigerant flowing through the first passage and a low-pressure side refrigerant flowing through the second passage; In the internal heat exchanger that exchanges heat between
A low-pressure outlet pipe extending from the inner pipe at one end of the outer pipe;
An expansion valve housing cylinder having both ends constituted by the low-pressure outlet pipe and an end of the inner pipe arranged coaxially with the low-pressure outlet pipe, and the middle being separated from the low-pressure outlet pipe by the end of the inner pipe;
A return inlet pipe penetrating the outer pipe and the inner pipe and joined to the inner position adjacent to the portion constituting the expansion valve storage cylinder of the inner pipe;
An expansion valve housed in the expansion valve housing tube;
With
The expansion valve has a cylindrical expansion valve body having a high pressure inlet at a side and a low pressure outlet at one end in the axial direction, and a power element coupled to the other axial end of the expansion valve body. In the expansion valve storage cylinder, the power element is disposed in the second passage in the vicinity where the power element is located at the end of the inner pipe and the return inlet pipe is joined, and the high pressure inlet Is communicated with the first passage through the middle of the expansion valve housing cylinder, and the low-pressure outlet communicates with the low-pressure outlet pipe. An inner tube is coaxially arranged in the outer tube to form a first passage and a second passage, and a high-pressure side refrigerant flowing through the first passage and a low-pressure side refrigerant flowing through the second passage; In the internal heat exchanger that exchanges heat between
An end of the outer tube extending from the inner tube at one end of the outer tube;
An expansion valve storage cylinder having both ends constituted by the end of the outer pipe and the end of the inner pipe arranged coaxially therewith, and the middle being separated from the end of the outer pipe by the end of the inner pipe When,
A return inlet pipe penetrating and joining the outer pipe and the inner pipe to an inner position adjacent to an end of the inner pipe constituting the expansion valve housing cylinder;
A low pressure outlet pipe joined to the side surface of the end of the outer pipe on the side where the return inlet pipe is joined;
An expansion valve housed in the expansion valve housing tube;
With
The expansion valve has a cylindrical expansion valve body having a high pressure inlet at a side and a low pressure outlet at one end in the axial direction, and a power element coupled to the other axial end of the expansion valve body. In the expansion valve storage cylinder, the power element is disposed in the second passage in the vicinity where the power element is located in the inner pipe and the return inlet pipe is joined, and the high pressure inlet is in the expansion pipe. The expansion valve housing is communicated with the first passage through the middle of the valve housing cylinder, the low pressure outlet communicates with the low pressure outlet pipe, and the expansion valve is accommodated in the expansion valve housing cylinder. An internal heat exchanger characterized in that the open end of the cylinder is closed with a plug.   8. The expansion valve according to claim 4, wherein an outer diameter of the power element is made smaller than an outer diameter of the expansion valve body so that the expansion valve can be inserted into the expansion valve housing cylinder from the power element. Internal heat exchanger as described in.   The internal heat exchanger according to claim 4 or 5, wherein the expansion valve is held in the expansion valve storage cylinder by connecting a pipe to an evaporator to the low-pressure outlet side collecting pipe.   The internal heat exchanger according to claim 6, wherein the expansion valve is held in the expansion valve housing cylinder by connecting a pipe to an evaporator to the low pressure outlet pipe.   The internal heat exchanger according to claim 7, wherein the expansion valve is held in the expansion valve storage cylinder by closing an end portion of the outer pipe constituting the expansion valve storage cylinder with the plug.

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