JP2009092276A - Refrigerating cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle comprising an internal heat exchanger of a double tube structure not needing a branching device at an end portion. <P>SOLUTION: A piping block 14 of a liquid receiver 3 comprises connection ports 15, 16 with which the internal heat exchanger 6 of the double tube structure can be directly connected, a connection port 18 with which a low-pressure pipe 12 to a compressor 1 is connected, and a connection port 17 with which a high-pressure pipe 11 from a condenser 2 is connected, and has a function as joints of the pipes of the liquid receiver 3, and a function for branching high pressure and low pressure. As the piping block 14 has the branching function, the internal heat exchanger 6 of the double tube structure can dispense with the branching device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle of an air conditioner for automobiles, and particularly, internal heat exchange for exchanging heat between a high-temperature / high-pressure refrigerant sent to an inlet of an expansion valve and a low-temperature / low-pressure refrigerant sent to a compressor inlet The present invention relates to a refrigeration cycle equipped with a vessel.

  The refrigeration cycle of an automotive air conditioner generally stores a compressor driven by an engine for vehicle travel, a condenser that condenses the high-temperature and high-pressure gas refrigerant compressed by the compressor, and the condensed liquid refrigerant. An expansion valve that squeezes and expands the high-temperature and high-pressure liquid refrigerant into a low-temperature and low-pressure gas-liquid mixed vapor, and an evaporator that evaporates the expanded refrigerant and returns it to the compressor Yes.

  In such a refrigeration cycle, as an expansion valve that squeezes and expands the liquid refrigerant, the temperature and pressure of the refrigerant at the outlet of the evaporator is sensed, and the refrigerant at the outlet of the evaporator maintains a predetermined degree of superheat. In many cases, a temperature type expansion valve that controls the flow rate of the supplied refrigerant is used.

  Moreover, in order to raise the efficiency of the system of a refrigerating cycle, what was equipped with the internal heat exchanger is known (for example, refer patent document 1). The internal heat exchanger described in Patent Document 1 includes a high-temperature and high-pressure liquid refrigerant sent from the receiver to the inlet of the expansion valve, and a low-temperature and low-pressure gas refrigerant sent from the evaporator to the compressor inlet. Heat exchange between the two. As a result, the refrigerant entering the expansion valve is further cooled by the internal heat exchanger to lower the enthalpy of the refrigerant at the inlet of the expansion valve, and at the same time, the refrigerant leaving the evaporator is further superheated by the internal heat exchanger. This increases the enthalpy of the refrigerant at the compressor inlet and increases the enthalpy difference between the inlet of the evaporator and the inlet of the compressor. The efficiency and refrigeration capacity of the system can be improved.

The internal heat exchanger described in Patent Document 1 has a double pipe structure in which an inner pipe is disposed substantially concentrically in an outer pipe, and a high-temperature and high-pressure liquid refrigerant is allowed to flow in a certain direction through the inner pipe. In the space between the inner tube and the outer tube, a low-temperature and low-pressure gas refrigerant flows in the opposite direction, and the liquid refrigerant and the gas refrigerant exchange heat through the inner tube. At both ends of the internal heat exchanger, branch devices for branching both refrigerants are provided. This branching device has a high-temperature pipe and a low-temperature pipe for high-temperature and high-pressure liquid refrigerant by brazing the inner pipe through the bent portion formed near both ends of the outer pipe so as to close the gap between them. -It has the branch part branched to the low-pressure piping for low-pressure gas refrigerant, and the joint block provided in the front-end | tip part of high-pressure piping and low-pressure piping, respectively. One of these joint blocks is connected to the high-pressure inlet and the low-pressure outlet of the temperature type expansion valve, and the other is connected to the high-pressure pipe from the liquid receiver and the low-pressure pipe to the suction port of the compressor.
Japanese Patent Laying-Open No. 2007-55553 (FIG. 4)

  However, since the internal heat exchanger with a double-pipe structure always requires a branching device that branches high and low pressure at both ends, there is a problem that the cost of the air conditioner for automobiles is increased accordingly. .

  This invention is made | formed in view of such a point, and it aims at providing the refrigerating cycle provided with the internal heat exchanger of the double pipe structure which does not require a branch device in the edge part.

  In the present invention, in order to solve the above problem, an internal heat exchanger that performs heat exchange between the high-temperature and high-pressure refrigerant sent to the inlet of the expansion valve and the low-temperature and low-pressure refrigerant sent to the suction port of the compressor is provided. In the refrigeration cycle provided, the internal heat exchanger has a double pipe structure in which the inner pipe is arranged substantially concentrically in the outer pipe, and one end thereof is connected to the receiver. The liquid receiver includes first and second connection ports that connect one end of the internal heat exchanger in a double tube structure and a third connection port to which a low-pressure pipe to the suction port of the compressor is connected. There is provided a refrigeration cycle characterized in that a refrigeration cycle is provided.

  According to such a refrigeration cycle, one end of an internal heat exchanger having a double-pipe structure is connected to a receiver having a piping block that branches into a high pressure and a low pressure and has a function of a joint of its own piping. Configured to do. As a result, the internal heat exchanger need not be attached to the end of the internal heat exchanger, and the overall configuration can be simplified.

  In the refrigeration cycle according to the present invention, the internal heat exchanger having a double pipe structure is connected to a liquid receiver having a function of branching into a high pressure and a low pressure as a double pipe structure, so that a branching device is not required. Therefore, there is an advantage that the cost of the air conditioner for automobiles can be reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, taking a refrigeration cycle of an automotive air conditioner as an example.
1 is a system diagram showing a cross section of the refrigeration cycle according to the first embodiment around the internal heat exchanger, FIG. 2 is a cross-sectional view of the liquid receiver of FIG. It is a figure which shows the piping block of a liquid device, (A) is sectional drawing of the hollow extrusion molding material which is a raw material of a piping block, (B) is a top view of a piping block, (C) is for low pressure piping of a piping block It is the end elevation seen from the connection port side.

  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 liquid receiver 3 for sending out liquid refrigerant. An expansion valve 4 for adiabatic expansion of the liquid refrigerant and an evaporator 5 for evaporating the expanded refrigerant are disposed in the vehicle interior. The liquid receiver 3 and the compressor 1 are connected to the expansion valve 4 by an internal heat exchanger 6 having a double pipe structure.

  The internal heat exchanger 6 includes a first double pipe 7 having a first inner pipe 7a and a first outer pipe 7b arranged in the engine room, and a second inner pipe 8a and a second second pipe arranged in the vehicle interior. A second double pipe 8 having an outer pipe 8b. The first double pipe 7 and the second double pipe 8 are provided by a pipe clamp 10 at a penetrating portion of the partition wall 9 separating the engine room and the vehicle compartment. Are combined.

  The internal heat exchanger 6 does not have a branch device for connecting to the high-pressure pipe 11 and the low-pressure pipe 12 required at the end portion on the compressor 1 side, and has a branch function as a component of the liquid receiver 3. I try to make it. The liquid receiver 3 includes a covered cylindrical main body case 13 and a piping block 14, and these connecting portions are welded so that there is no refrigerant leakage. The piping block 14 has a structure that doubles as its piping joint and a branch of the internal heat exchanger 6.

  That is, the piping block 14 is connected to the concentric connection ports 15 and 16 to which the first double pipe 7 having the first inner pipe 7a and the first outer pipe 7b can be connected as a double pipe and the high-pressure pipe 11. Connecting port 17 and a connecting port 18 to which the low-pressure pipe 12 is connected. The connection port 15 to which the first inner pipe 7a of the first double pipe 7 is connected is a refrigerant at the bottom of the lower liquid reservoir chamber 20 in which the inside of the main body case 13 is divided into two by the desiccant / filter 19 in the direction of gravity. Communication is made via a passage 21. As shown in FIG. 2, the connection port 16 communicates with a connection port 18 to which the low-pressure pipe 12 is connected via a refrigerant passage 22 disposed on both sides of the pipe block 14. The connection port 17 to which the high-pressure pipe 11 is connected is provided at the bottom of the pipe block 14 and communicates with a refrigerant passage 23 formed so as to penetrate through the extension line. Further, the desiccant / filter 19 is passed through the refrigerant passage 23. It communicates with the upper chamber 25 in the direction of gravity via a pipe 24 arranged in the main body case 13 so as to penetrate.

  Connection portions between the connection ports 15 and 16 of the pipe block 14 and the first inner pipe 7a and the first outer pipe 7b of the first double pipe 7 are sealed by an O-ring, and the pipe block 14 and the first double pipe 7 are connected. These connection portions are fixed by caulking the cylindrical tip portion of the connection port 16 of the piping block 14.

  Here, the piping block 14 is preferably formed by machining a hollow extruded material 26 as shown in FIG. The hollow extrusion molding material 26 has a shape in which a cylindrical portion 27 and a strip plate portion 28 that are long in the extrusion direction are integrally formed. In the cylindrical portion 27, a hollow portion 22 a that becomes the refrigerant passage 22 is formed. Such a hollow extrusion molding material 26 is cut into blocks having an appropriate length, and the band plate portion 28 is cut to process the fitting portion 29 with the main body case 13 as shown in FIG. Refrigerant passages 21 and 23 are formed. Further, the connection ports 15 and 16 are formed by cutting one end surface of the cylindrical portion 27, and the connection port 18 as shown in FIG. 3C is formed by cutting the other end surface. . Further, the connection port 17 is formed by cutting the bottom surface of the cylindrical portion 27.

  The internal heat exchanger 6 can be connected to the piping block 14 of the receiver 3 with the end portion on the compressor 1 side being in a double tube structure, but the end portion on the expansion valve 4 side is also in a double tube structure. It can be connected to the expansion valve 4 as it is. Next, a configuration example of the expansion valve 4 to which the internal heat exchanger 6 can be connected with a double pipe structure will be described.

FIG. 4 is a cross-sectional view showing a configuration example of an expansion valve having a double pipe connection structure. In addition, the arrow in a figure has shown the flow direction of the refrigerant | coolant.
This expansion valve 4 is a temperature type expansion valve that is directly connected to the evaporator 5, and has a double pipe connection structure in connection with the evaporator 5 as well as the internal heat exchanger 6. ing. Therefore, in the evaporator 5, the refrigerant inlet pipe 30 for introducing the refrigerant and the refrigerant outlet pipe 31 for leading out the refrigerant have a double pipe structure, and the refrigerant inlet pipe so that the refrigerant outlet pipe 31 surrounds the refrigerant inlet pipe 30. 30 and substantially coaxial.

  The expansion valve 4 includes a body 32 having a shape in which a cylinder intersects in a T-shape, and three end face shapes each have a double tube structure. That is, at one end face of the body 32, the inner pipe is a low-pressure refrigerant outlet 33, the outer pipe is a return low-pressure refrigerant inlet 34, and the refrigerant inlet pipe 30 and the refrigerant outlet pipe 31 formed integrally with the evaporator 5 are connected. Each is connected. The end surface of the body 32 opposite to the side connected to the evaporator 5 is sealed by caulking all around so as to lock the outer peripheral edge of the power element 35. The power element 35 includes an upper housing 36, a lower housing 37, a diaphragm 38, and a center disk 39. A space surrounded by the upper housing 36 and the diaphragm 38 constitutes a temperature-sensitive greenhouse, which is filled with a gas having the same or similar characteristics as the refrigerant of the refrigeration cycle. The lower housing 37 has its open ends bent alternately inward and outward in the circumferential direction, the outer bent portion is used to prevent the seal O-ring from falling off, and the inner bent portion is the center disc 39. It is a stopper to prevent falling off. And the part extended below the figure from the center part of the body 32 is a connection part with the 2nd double pipe 8 of the internal heat exchanger 6, Comprising: The inner pipe comprises the high voltage | pressure refrigerant inlet 40. FIG. The outer pipe returns and constitutes the low-pressure refrigerant outlet 41. The high pressure refrigerant inlet 40 and the return low pressure refrigerant outlet 41 are connected to the second inner pipe 8a and the second outer pipe 8b of the second double pipe 8, respectively.

  The low-pressure refrigerant outlet 33 of the body 32 is formed with a central hole penetrating toward the power element 35. For example, four low-pressure refrigerant passages are formed in parallel around the central hole, although not shown. In the center hole, a valve shaft guide 42 and a ring-shaped valve seat 43 are fitted and fixed to the body 32 by caulking. A valve element 44 is arranged so as to be able to contact and separate from the valve seat 43. The valve body 44 is formed integrally with a valve shaft 45 extending in the axial direction via the valve seat 43 and the valve shaft guide 42. A cylindrical collar member 46 is fitted to the end of the valve shaft 45 opposite to the side on which the valve body 44 is formed, and on the valve body 44 side, a sealing O-ring is provided. 47 is arranged. The collar member 46 is in contact with the center disk 39 of the power element 35 and transmits the displacement of the diaphragm 38 to the valve body 44. The collar member 46 has an outer diameter substantially equal to the inner diameter of the valve hole of the valve seat 43, thereby canceling the pressure of the refrigerant introduced into the expansion valve 4.

  The valve body 44 is urged in the valve closing direction by a spring 48, and the spring 48 is received by a spring receiving member 49 press-fitted into the low-pressure refrigerant outlet 33, and the spring receiving member 49 is connected to the inner pipe. The load of the spring 48 is adjusted by the press-fitting amount.

  In the refrigeration cycle including the liquid receiver 3, the internal heat exchanger 6 and the expansion valve 4 as described above, when the automotive air conditioner starts operation, the refrigerant compressed by the compressor 1 to a high temperature and high pressure is It is sent to the condenser 2 where it is condensed. The condensed refrigerant is sent to the liquid receiver 3 through the high-pressure pipe 11. The refrigerant introduced into the liquid receiver 3 is sent to the upper chamber 25 in the gravity direction via the pipe 24, passes through the desiccant / filter 19, and flows down to the lower chamber 20 in the gravity direction. At this time, the desiccant / filter 19 removes moisture that has entered the cycle and removes foreign matter in the cycle. The liquid refrigerant accumulated in the room 20 passes through the refrigerant passage 21 and is sent from the connection port 15 to the internal heat exchanger 6. In the internal heat exchanger 6, the introduced liquid refrigerant passes through the first inner pipe 7 a of the first double pipe 7 and the second inner pipe 8 a of the second double pipe 8, and the high-pressure refrigerant inlet of the expansion valve 4. 40.

  The liquid refrigerant supplied to the expansion valve 4 flows out to the low-pressure refrigerant outlet 33 through the gap between the valve seat 43 and the valve body 44. 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 5 through the refrigerant inlet pipe 30. In the evaporator 5, the introduced refrigerant is evaporated by heat exchange with the air in the passenger compartment and flows out from the refrigerant outlet pipe 31. The refrigerant is introduced into the expansion valve 4 from the return low-pressure refrigerant inlet 34, passes through the low-pressure refrigerant passage, and flows out to the low-pressure refrigerant outlet 41. Since the passage of the low-pressure refrigerant communicates with the space surrounded by the diaphragm 38 and the lower housing 37 of the power element 35, the temperature and pressure of the refrigerant returned from the evaporator 5 are detected by the power element 35. . Since the pressure in the temperature sensitive room rises and falls according to the detected temperature and pressure of the refrigerant, the diaphragm 38 is displaced in the opening / closing direction of the valve body 44 according to the temperature and pressure. The displacement is transmitted to the collar member 46 via the center disk 39 and further transmitted to the valve body 44 via the valve shaft 45. As a result, the lift of the valve body 44 changes, and the flow rate of the refrigerant supplied to the evaporator 5 is controlled. That is, the expansion valve 4 senses the temperature and pressure of the refrigerant exiting the evaporator 5 and controls the flow rate of the refrigerant supplied to the evaporator 5 so that the refrigerant maintains a predetermined degree of superheat. Become.

  The refrigerant exiting the expansion valve 4 is introduced into the internal heat exchanger 6. In the internal heat exchanger 6, the introduced refrigerant passes through the space between the second inner pipe 8 a and the second outer pipe 8 b of the second double pipe 8 and the first inner pipe 7 a of the first double pipe 7. It flows through the space between the first outer pipe 7b. At this time, in the internal heat exchanger 6, the high-temperature and high-pressure refrigerant flowing through the first inner pipe 7a and the second inner pipe 8a, the space between the second inner pipe 8a and the second outer pipe 8b, and the first inner pipe The low-temperature and low-pressure refrigerant flowing in the space between the pipe 7a and the first outer pipe 7b exchanges heat through the first inner pipe 7a and the second inner pipe 8a, and more refrigerant is supplied to the expansion valve 4. At the same time, the refrigerant returned to the compressor 1 is further superheated to improve the coefficient of performance of the refrigeration cycle.

  The refrigerant from the expansion valve 4 that has passed through the internal heat exchanger 6 enters the connection port 16 of the liquid receiver 3, reaches the connection port 18 through the refrigerant passage 22 of the piping block 14, and passes through the low-pressure piping 12 from there. To the suction port of the compressor 1.

  FIG. 5 is a cross-sectional view of a liquid receiver used in the refrigeration cycle according to the second embodiment, FIG. 6 is a view showing a pipe block of the liquid receiver, and (A) is a hollow that is a material of the pipe block. Sectional drawing of an extrusion molding material, (B) is a top view of a piping block, (C) is an end view of a piping block. 5 and 6, the same components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Since this refrigeration cycle differs from the refrigeration cycle shown in FIG. 1 only in the configuration of the liquid receiver 3a, only the liquid receiver 3a will be described here. In this liquid receiver 3 a, the positions of the connection port 17 to which the high pressure pipe 11 is connected and the connection port 18 to which the low pressure pipe 12 is connected are exchanged as compared with the pipe block 14 of the liquid receiver 3.

  That is, the piping block 14 is connected to the concentric connection ports 15 and 16 to which the first double pipe 7 having the first inner pipe 7a and the first outer pipe 7b can be connected as a double pipe and the high-pressure pipe 11. And a connection port 18 to which the low-pressure pipe 12 is connected at the bottom of the piping block 14.

  The piping block 14 is preferably formed from a hollow extruded material 26a having a cross section as shown in FIG. The hollow extrusion molding material 26 a has a shape in which a cylindrical portion 27 and band plate portions 28 a and 28 b arranged so as to sandwich the cylindrical portion 27 are integrally formed. The cylindrical portion 27 corresponds to the refrigerant passage 22. A U-shaped hollow portion 22b is formed. Such a hollow extrusion molding material 26a is cut into blocks having an appropriate length, and the band plate portion 28a is cut to process the fitting portion 29 with the main body case 13 as shown in FIG. Refrigerant passages 21 and 23 are formed. Further, as shown in FIG. 6C, the connection ports 15 and 16 are formed by cutting one end surface of the cylindrical portion 27, and the connection port 17 is formed by cutting the other end surface. The Further, the connection port 18 is formed by cutting the bottom surface of the cylindrical portion 27. In addition, the end surface where the connection port 17 of the high-pressure pipe 11 is formed is cut in the same manner as the end surface on the opposite side to form a cylindrical portion 50 concentric with the central connection port 17. In this cylindrical part 50, the closing member 51 which closes the refrigerant path 22 is arrange | positioned, and is fixed by caulking. The closing member 51 is sealed by welding to the high-pressure pipe 11 passing through the center thereof, and the outer peripheral portion is sealed by an O-ring.

  According to such a piping block 14, all of the sealing portions of the connection ports 16, 18 and the cylindrical portion 50 by the O-ring with respect to the outside air are on the low pressure side, and the high pressure side seal which is inherently susceptible to leakage is low pressure. It can be placed in the passage. As a result, even if there is a refrigerant leak at the high pressure side seal portion, the refrigerant does not leak into the atmosphere because it leaks in the low pressure passage.

  FIG. 7 is a cross-sectional view of a liquid receiver used in the refrigeration cycle according to the third embodiment. In FIG. 7, the same components as those shown in FIGS. 2 and 5 are given the same reference numerals, and detailed description thereof is omitted.

  In the refrigeration cycle receiver 3b, the refrigeration cycle receiver 3b shown in FIG. 1 enables the high pressure pipe 11 to be connected to the bottom of the pipe block 14, whereas the high pressure pipe 11 is connected to the pipe block 14. Can be connected from the side. For this reason, in the piping block 14, the connection port 17 opens in a direction orthogonal to the direction in which the refrigerant passage 22 is formed and the direction in which the pipe 24 is erected, and the high-pressure piping 11 is connected thereto. Is done. Thereby, since the piping block 14 can change the connection direction of the high-pressure piping 11, the space for piping bending becomes unnecessary in the place where piping needs to be bent.

  Such a piping block 14 is preferably made of a hollow extruded material having a hollow portion that is substantially L-shaped as a refrigerant passage 22 and is subjected to cutting similar to that shown in FIG. It is formed.

  FIG. 8 is a cross-sectional view of a liquid receiver used in the refrigeration cycle according to the fourth embodiment. In FIG. 7, the same components as those shown in FIGS. 2, 5, and 7 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The liquid receiver 3c of the refrigeration cycle has a high-pressure pipe 11 connected to the top of the main body case 13 so that the condensed refrigerant is directly fed into the upper chamber 25 in the direction of gravity. Therefore, the liquid receiver 3c does not have the pipe 24 for feeding the refrigerant from the piping block 14 to the upper chamber 25 in the gravity direction, and does not have the connection port 17 for connecting the high-pressure piping 11 to the piping block 14.

  For this reason, the connection block 15 and 16 which connect the 1st double pipe 7 is formed in the one end part of the piping block 14 in the direction in which the refrigerant path 22 is formed, and low-pressure piping is formed in the other end part. 12 is formed, and a refrigerant passage 21 that connects the connection port 15 to the lower chamber 20 in the direction of gravity is formed.

  In the above embodiment, the case where the expansion valve 4 is a temperature type expansion valve has been described. However, the expansion valve 4 is not limited to the temperature type expansion valve, and various types of expansion valves can be used. Hereinafter, as another example of the expansion valve 4, a configuration example of an electronic expansion valve corresponding to the internal heat exchanger 6 having a double-pipe structure is shown.

FIG. 9 is a cross-sectional view showing an electronic expansion valve having a double pipe connection structure.
Similar to the expansion valve 4 shown in FIG. 4, the electronic expansion valve 61 includes a body 62 having a shape in which a cylinder intersects in a T-shape, and each of the three end surfaces has a double tube structure, and is evaporated. A solenoid 63 is attached to the end surface opposite to the attachment end to the device 5. A valve shaft guide 64 and a ring-shaped valve seat 65 are disposed in a central hole formed in the center from the evaporator 5 side of the body 62 toward the solenoid 63, and the valve body 66 is closed by a spring 67 on the downstream side thereof. It is arranged in a state of being biased in the valve direction. The valve body 66 is formed integrally with a valve shaft 68 extending in the axial direction via a valve seat 65 and a valve shaft guide 64. A diaphragm 69 is attached so as to close an inner tube that opens on the solenoid 63 side of the body 62, and a valve shaft 68 is fixed to the diaphragm 69 in a penetrating manner. A pressure equalizing hole 70 is formed in the body 62 so that the evaporator inlet pressure Px is introduced to the pressure receiving surface of the diaphragm 69 opposite to the solenoid 63 side. The pressure receiving surface on the solenoid 63 side of the diaphragm 69 is in communication with the refrigerant outlet pipe 31 of the evaporator 5 and is configured to receive the evaporator outlet pressure Pe. Therefore, the diaphragm 69 constitutes a differential pressure sensing unit that senses the evaporator differential pressure (Px−Pe).

  The solenoid 63 has a core 71 attached so as to close the outer tube that opens to the solenoid 63 side of the body 62. The core 71 is fitted with an open end of a bottomed sleeve 72 extending in the same direction as the valve shaft 68, and a plunger 73 is disposed in the bottomed sleeve 72 so as to be able to advance and retreat in the axial direction. The plunger 73 is fixed to a shaft 74 that passes through the core 71 and extends coaxially with the valve shaft 68. The shaft 74 is a bearing portion fixed to the core 71 and a bearing formed at the bottom of the bottomed sleeve 72. Both ends are supported by the part. The solenoid 63 also includes a coil 75 that is provided around the outer side of the bottomed sleeve 72 and a yoke 76 that is disposed so as to surround the coil 75.

  In the electronic expansion valve 61 having the above configuration, when the automotive air conditioner is stopped and the coil 75 is not energized, the valve element 66 is seated on the valve seat 65 by the urging force of the spring 67 and is closed. ing.

  Here, when the automotive air conditioner is activated and the coil 75 of the solenoid 63 is energized, the plunger 73 is attracted by the core 71 and the shaft 74 fixed to the plunger 73 against the urging force of the spring 67 is a valve. The valve shaft 68 integral with the body 66 is pushed in the valve opening direction to open the valve. The lift of the valve body 66 is determined by the magnitude of the current supplied to the coil 75. As a result, when the high-temperature and high-pressure liquid refrigerant is supplied through the second inner pipe 8a of the second double pipe 8, the liquid refrigerant passes through the gap between the valve seat 65 and the valve body 66, and the evaporator. 5 flows out to the refrigerant inlet pipe 30. 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 5 from the refrigerant inlet pipe 30. In the evaporator 5, the introduced refrigerant is evaporated by heat exchange with the air in the passenger compartment, flows out of the refrigerant outlet pipe 31, and is reintroduced into the electronic expansion valve 61. The introduced refrigerant passes through the low-pressure refrigerant passage of the body 62 and flows out to the second outer pipe 8 b of the second double pipe 8.

  At this time, the evaporator outlet pressure Pe is applied in the valve opening direction to the surface on the solenoid 63 side of the diaphragm 69, and the evaporator inlet pressure Px is applied in the valve closing direction to the opposite surface. The diaphragm 69 senses the pressure difference across the evaporator (Px-Pe) and controls the valve lift.

  When the electronic expansion valve 61 supplies the refrigerant to the evaporator 5 with a predetermined valve lift set by the solenoid 63, the flow rate of the refrigerant passing through the evaporator 5 increases and the pressure loss in the evaporator 5 is reduced. When the pressure increases, the evaporator front-rear differential pressure (Px−Pe) increases, so that the valve body 66 is driven in the valve closing direction to act to throttle the flow rate. Conversely, when the flow rate of the refrigerant passing through the evaporator 5 decreases and the evaporator differential pressure (Px−Pe) decreases, the valve body 66 is driven in the valve opening direction to act to increase the flow rate. Therefore, the electronic expansion valve 61 operates to control the flow rate of the refrigerant sent to the evaporator 5 to be substantially constant by controlling the pressure difference between the inlet and the outlet of the evaporator 5 to be constant. The pressure is freely set by the solenoid 63. Note that the magnitude of the current supplied to the coil 75 of the solenoid 63 to control the electronic expansion valve 61 is appropriately set based on, for example, a refrigeration load.

  According to such an electronic expansion valve 61, a valve unit that senses the pressure difference across the evaporator (Px−Pe) and controls the pressure difference to be constant, and a solenoid 63 that sets the pressure difference from the outside, Therefore, the overall configuration is simplified, and further, the cost can be reduced because a power element having a high component cost is not used.

It is the system figure which showed the refrigerating cycle which concerns on 1st Embodiment about the internal heat exchanger periphery in the cross section. It is an aa arrow directional cross-sectional view of the liquid receiver of FIG. It is a figure which shows the piping block of a liquid receiver, Comprising: (A) is sectional drawing of the hollow extrusion molding material which is a raw material of a piping block, (B) is a top view of a piping block, (C) is the low voltage | pressure piping of a piping block It is the end elevation seen from the connection port side. It is sectional drawing which shows the structural example of the expansion valve which has a double pipe connection structure. It is sectional drawing of the liquid receiver used for the refrigerating cycle which concerns on 2nd Embodiment. It is a figure which shows the piping block of a receiver, (A) is sectional drawing of the hollow extrusion molding material which is a raw material of a piping block, (B) is a top view of a piping block, (C) is an end elevation of a piping block It is. It is sectional drawing of the liquid receiver used for the refrigerating cycle which concerns on 3rd Embodiment. It is sectional drawing of the liquid receiver used for the refrigerating cycle which concerns on 4th Embodiment. It is sectional drawing which shows the electronic expansion valve which has a double pipe connection structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3, 3a, 3b, 3c Liquid receiver 4 Expansion valve 5 Evaporator 6 Internal heat exchanger 7 1st double pipe 7a 1st inner pipe 7b 1st outer pipe 8 2nd double pipe 8a Second inner pipe 8b Second outer pipe 9 Bulkhead 10 Pipe clamp 11 High pressure pipe 12 Low pressure pipe 13 Body case 14 Pipe block 15, 16, 17, 18 Connection port 19 Desiccant / filter 20 Room 21, 22 Refrigerant passage 22a, 22b Hollow part 23 Refrigerant passage 24 Pipe 25 Room 26, 26a Hollow extrusion molding material 27 Cylindrical part 28, 28a, 28b Strip plate part 29 Fitting part 30 Refrigerant inlet pipe 31 Refrigerant outlet pipe 32 Body 33 Low pressure refrigerant outlet 34 Return low pressure refrigerant inlet 35 Power element 36 Upper housing 37 Lower housing 38 Diaphragm 39 Center disk 40 High-pressure refrigerant inlet 41 Return low pressure refrigerant outlet 42 Valve shaft guide 43 Valve seat 44 Valve body 45 Valve shaft 46 Collar member 47 O-ring 48 Spring 49 Spring receiving member 50 Cylindrical portion 51 Closing member 61 Electronic expansion valve 62 Body 63 Solenoid 64 Valve shaft guide 65 Valve seat 66 Valve body 67 Spring 68 Valve shaft 69 Diaphragm 70 Pressure equalizing hole 71 Core 72 Bottomed sleeve 73 Plunger 74 Shaft 75 Coil 76 Yoke

Claims (8)

In a refrigeration cycle having an internal heat exchanger that exchanges heat between a high-temperature and high-pressure refrigerant sent to the inlet of the expansion valve and a low-temperature and low-pressure refrigerant sent to the suction port of the compressor,
The internal heat exchanger has a double pipe structure in which the inner pipe is arranged substantially concentrically in the outer pipe, and one end of the inner heat exchanger is connected to the liquid receiver.
The liquid receiver includes first and second connection ports that connect one end of the internal heat exchanger in a double tube structure and a third connection port to which a low-pressure pipe to the suction port of the compressor is connected. A refrigeration cycle comprising a piping block having:   The piping block of the liquid receiver is in a first chamber of a liquid reservoir in which the first connection port to which the inner pipe of the internal heat exchanger is connected is formed in a body case of the liquid receiver. A space between the second connection port and the first connection port connected to each other and connected to the outer pipe of the internal heat exchanger communicates with the third connection port via an internal refrigerant passage. The refrigeration cycle according to claim 1, wherein   The piping block of the liquid receiver has a fourth connection port to which a high-pressure piping from a condenser is connected, and the fourth connection port is a desiccant in the main body case with the first chamber. 3. The refrigeration cycle according to claim 2, wherein the refrigeration cycle is communicated with a second chamber separated by a filter via a pipe.   The main body case of the receiver has a fourth connection port to which a high-pressure pipe from a condenser is connected, and the fourth connection port is separated from the first chamber by a desiccant / filter. The refrigeration cycle according to claim 2, wherein the refrigeration cycle communicates with the second room.   The outer pipe of the internal heat exchanger and the piping block of the receiver are sealed with an O-ring between the outer pipe and the second connection port of the piping block to which the outer pipe is connected, 2. The refrigeration cycle according to claim 1, wherein the pipe block blocks forming the two connection ports are fixed to each other by caulking.   The refrigeration cycle according to claim 1, wherein the piping block of the liquid receiver is formed by machining a hollow extruded material.   The hollow extruded material is formed by machining the first and second connection ports and the third connection port on both sides of the extrusion direction, and the second connection port and the first connection port are formed inside. A hollow portion extending in the extrusion direction from the position between the connection port toward the third connection port is formed at the time of extrusion molding, and the fitting portion for fitting the body case of the liquid receiver is formed by machining. The refrigeration cycle according to claim 6, wherein the refrigeration cycle is formed.   The refrigerating cycle according to claim 1, wherein the other end of the internal heat exchanger is connected to an expansion valve having a connection structure that can be connected in a double tube structure.

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