JP2018021595A - Double pipe and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a spiral member to a pipe member without changing flow passage resistance.SOLUTION: A double pipe 60 has: an inner pipe 62 in which a gaseous refrigerant flows; and an outer pipe 63 in which the inner pipe 62 is inserted into an inner periphery and a liquid refrigerant flows between itself and the inner pipe 62. The inner pipe 62 has: a pipe member 64 formed into a cylindrical shape; a spiral member 65 which is inserted into an inner periphery of the pipe member 64 and guides flow of the gaseous refrigerant in a spiral form; and a diameter expanding part 65b in which at least a part of the spiral member 65 expands its diameter and makes pressure contact with the inner periphery of the pipe member 64.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a double pipe and a method for producing the same.

  Patent Document 1 includes a pipe member through which EGR (Exhaust Gas Recirculation) gas circulates, and a spiral member that stirs EGR gas through the inner periphery of the pipe member, and cools through the outside. A heat exchange tube that cools the EGR gas by heat exchange with water is disclosed. In this heat exchange tube, the tube member has a plurality of two-dimensional protrusions that are formed to protrude to the inner periphery and fix the spiral member.

JP 2000-179410 A

  However, in the heat exchange tube of Patent Document 1, a plurality of two-dimensional protrusions protrude from the inner periphery of the pipe member. Therefore, at the position where the two-dimensional protrusion protrudes, the flow path becomes narrower than other positions, and the flow path Resistance increases.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to fix a spiral member to a tube member without changing flow path resistance.

  According to an aspect of the present invention, a double pipe having an inner pipe through which a gaseous fluid flows and an outer pipe through which the inner pipe passes through an inner circumference and a liquid fluid flows between the inner pipe and the inner pipe. The inner tube includes a tube member formed in a cylindrical shape, a spiral member that guides the flow of a gaseous fluid in a spiral manner through the inner periphery of the tube member, and at least a part of the spiral member And a diameter-enlarged portion that is in pressure contact with the inner periphery of the tube member.

  According to another aspect of the present invention, a double pipe having an inner pipe through which a gaseous fluid flows and an outer pipe through which the inner pipe passes through an inner circumference and a liquid fluid flows between the inner pipe and the inner pipe. A method of manufacturing a double pipe for manufacturing a pipe, wherein a spiral member that guides a flow of a gaseous fluid in a spiral manner is inserted into a cylindrical tubular member, and at least one of the spiral members And a diameter expanding step for expanding the diameter of the portion and press-contacting with the inner periphery of the tube member.

  In the said aspect, at least one part of a spiral member is diameter-expanded and a diameter-expansion part is formed. The spiral member is attached to the pipe member by the enlarged diameter portion being pressed against the inner periphery of the pipe member. Therefore, since the flow path of the gaseous fluid is not narrowed for attaching the spiral member, the spiral member can be fixed to the tube member without changing the flow path resistance.

FIG. 1 is a configuration diagram of an air conditioner to which a double pipe according to an embodiment of the present invention is applied. FIG. 2 is a diagram illustrating a heating mode of the air conditioner. FIG. 3 is a diagram illustrating a cooling mode of the air conditioner. FIG. 4 is a cross-sectional view illustrating the overall configuration of the double pipe according to the first embodiment of the present invention. FIG. 5A is a cross-sectional view illustrating a method for manufacturing a double pipe according to the first embodiment of the present invention. FIG. 5B is a left side view of FIG. 5A. FIG. 6A is a cross-sectional view illustrating a method for manufacturing a double pipe according to a second embodiment of the present invention. 6B is a left side view of FIG. 6A. FIG. 7A is a cross-sectional view illustrating a method for manufacturing a double pipe according to a third embodiment of the present invention. FIG. 7B is a left side view of FIG. 7A. FIG. 8A is a cross-sectional view illustrating a method for manufacturing a double pipe according to a fourth embodiment of the present invention. FIG. 8B is a cross-sectional view of a double tube manufactured by the method shown in FIG. 8A.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the air conditioner 1 to which the double pipes 60, 260, 360, and 460 according to the first to fourth embodiments of the present invention are applied will be described with reference to FIG. Here, the air conditioner 1 to which the double pipe 60 is applied will be described.

  The air conditioner 1 includes a refrigeration cycle 2 in which a refrigerant as a fluid circulates, a high water temperature cycle 4 in which hot water circulates, an HVAC (Heating Ventilation and Air Conditioning) unit 5 through which air used for air conditioning in the passenger compartment passes, This is a heat pump system capable of cooling and heating that includes a controller 10 that controls the operation of a valve and the like. For example, HFC-134a is used as the refrigerant, and antifreeze is used as the hot water.

  The refrigeration cycle 2 includes a compressor 21, a water-cooled condenser 22, an outdoor heat exchanger 23, a liquid tank 24, a double pipe 60 as an internal heat exchanger, an evaporator 25, an accumulator 26, and a refrigerant. And a refrigerant flow path 20 connected so as to be circulated.

  The compressor 21 sucks and compresses the gaseous refrigerant. Thereby, the gaseous refrigerant becomes a high temperature and a high pressure.

  The water-cooled condenser 22 functions as a condenser that condenses the refrigerant after passing through the compressor 21 during heating. The water-cooled condenser 22 exchanges heat between the refrigerant that has become high temperature and high pressure by the compressor 21 and the hot water that circulates in the high water temperature cycle 4, and transmits the heat of the refrigerant to the hot water.

  The outdoor heat exchanger 23 is disposed, for example, in an engine room (a motor room in an electric vehicle) of a vehicle and performs heat exchange between the refrigerant and the outside air. The outdoor heat exchanger 23 functions as a condenser during cooling, and functions as an evaporator during heating. Outside air is introduced into the outdoor heat exchanger 23 as the vehicle runs or the outdoor fan 32 rotates.

  The liquid tank 24 temporarily stores the refrigerant that has passed through the outdoor heat exchanger 23 and condensed during cooling, and separates the refrigerant into a gaseous refrigerant and a liquid refrigerant. Only the separated liquid refrigerant flows from the liquid tank 24 to the double pipe 60.

  The double pipe 60 has an outer flow path 20b, which will be described later, through which liquid refrigerant guided from the liquid tank 24 flows, and an inner flow path 20a, which will be described later, through which gaseous refrigerant evaporated by the evaporator 25 flows. The double pipe 60 performs heat exchange using the temperature difference of the refrigerant between the inner flow path 20a and the outer flow path 20b. A specific configuration of the double tube 60 will be described later in detail with reference to FIG.

  The evaporator 25 is disposed in the HVAC unit 5 and evaporates the refrigerant by absorbing the heat of the air passing through the evaporator 25 during cooling. The refrigerant evaporated by the evaporator 25 flows through the double pipe 60 to the accumulator 26.

  The accumulator 26 temporarily accumulates the refrigerant flowing through the refrigerant flow path 20 and separates it into gas and liquid refrigerants. Only the separated gaseous refrigerant flows from the accumulator 26 to the compressor 21.

  A first expansion valve 27 and a second expansion valve 28 that decompress and expand the refrigerant are disposed in the refrigerant flow path 20. Further, a first on-off valve 29, a second on-off valve 30, and a third on-off valve 31 that switch the refrigerant flow by opening and closing are disposed in the refrigerant flow path 20.

  The first expansion valve 27 is disposed between the water-cooled condenser 22 and the outdoor heat exchanger 23, and decompresses and expands the refrigerant condensed by the water-cooled condenser 22. For the first expansion valve 27, for example, a fixed throttle or a variable throttle is used. For example, an orifice or a capillary tube can be used as the fixed throttle, and the throttle amount is set in advance so as to correspond to specific operating conditions frequently used. In addition, for example, an electromagnetic valve whose opening degree can be adjusted stepwise or steplessly can be used as the variable throttle.

  The second expansion valve 28 is disposed between the double pipe 60 and the evaporator 25 and decompresses and expands the liquid refrigerant that has passed through the double pipe 60. As the second expansion valve 28, a temperature type expansion valve whose opening degree is adjusted according to the temperature of the refrigerant that has passed through the evaporator 25 is used.

  The first on-off valve 29 and the third on-off valve 31 are opened during cooling and closed during heating. By opening the first on-off valve 29, the refrigerant compressed by the compressor 21 flows directly into the outdoor heat exchanger 23. Further, the third on-off valve 31 is opened, so that the liquid refrigerant that has passed through the double pipe 60 flows to the evaporator 25.

  The second on-off valve 30 is opened during heating and closed during cooling. When the second on-off valve 30 is opened, the refrigerant evaporated in the outdoor heat exchanger 23 flows directly into the accumulator 26.

  The high water temperature cycle 4 includes a water pump 41, a heater core 42, an auxiliary heater 43, a water cooling condenser 22, and a hot water flow path 40 that connects them so that hot water can be circulated.

  The water pump 41 feeds and circulates hot water in the hot water flow path 40.

  The heater core 42 is disposed in the HVAC unit 5 and heats the air by causing the air passing through the heater core 42 to absorb the heat of hot water during heating.

  The auxiliary heater 43 has a heater (not shown) inside, and heats the passing hot water. For example, a sheathed heater or a PTC (Positive Temperature Coefficient) heater is used as the heater.

  The HVAC unit 5 cools or heats air used for air conditioning. The HVAC unit 5 includes a blower 52 that blows air and an air mix door 53 that adjusts the amount of air passing through the heater core 42. The heater core 42 and the evaporator 25 are disposed in the HVAC unit 5, and the air blown from the blower 52 exchanges heat with the refrigerant flowing through the heater core 42 and the evaporator 25.

  The blower 52 is a blower that blows air into the HVAC unit 5.

  The air mix door 53 is installed on the blower 52 side of the heater core 42 arranged in the HVAC unit 5. The air mix door 53 opens the heater core 42 side during heating, and closes the heater core 42 side during cooling. The amount of heat exchange between the air and the hot water in the heater core 42 is adjusted by the opening degree of the air mix door 53.

  The air conditioner 1 is provided with a discharge pressure sensor 11, an outdoor heat exchanger outlet temperature sensor 12, an evaporator temperature sensor 13, and a water temperature sensor 14.

  The discharge pressure sensor 11 is installed in the refrigerant flow path 20 on the discharge side of the compressor 21 and detects the pressure of the gaseous refrigerant compressed by the compressor 21.

  The outdoor heat exchanger outlet temperature sensor 12 is installed in the refrigerant flow path 20 near the outlet of the outdoor heat exchanger 23 and detects the temperature of the refrigerant that has passed through the outdoor heat exchanger 23. The outdoor heat exchanger outlet temperature sensor 12 may be installed at the outlet portion of the outdoor heat exchanger 23.

  The evaporator temperature sensor 13 is installed on the downstream side of the air flow of the evaporator 25 of the HVAC unit 5 and detects the temperature of the air that has passed through the evaporator 25. Note that the evaporator temperature sensor 13 may be directly installed on the evaporator 25.

  The water temperature sensor 14 is installed in the hot water flow path 40 near the outlet of the auxiliary heater 43 and detects the temperature of the hot water that has passed through the auxiliary heater 43.

  The controller 10 includes a CPU, a ROM, a RAM, and the like, and causes the air conditioner 1 to exhibit various functions by reading out a program stored in the ROM by the CPU. The controller 10 receives signals from the discharge pressure sensor 11, the outdoor heat exchanger outlet temperature sensor 12, the evaporator temperature sensor 13, and the water temperature sensor 14. Note that a signal from an outside air temperature sensor (not shown) may be input to the controller 10.

  The controller 10 executes control of the refrigeration cycle 2 based on the input signal. That is, the controller 10 sets the output of the compressor 21 and executes the opening / closing control of the first opening / closing valve 29, the second opening / closing valve 30, and the third opening / closing valve 31, as indicated by the broken line in FIG. The controller 10 also executes control of the high water temperature cycle 4 and the HVAC unit 5 by transmitting an output signal (not shown).

  Hereinafter, each air-conditioning operation mode of the air conditioner 1 will be described with reference to FIGS. 2 and 3.

<Heating mode>
First, the heating mode will be described with reference to FIG. In the heating mode, a so-called outdoor air endothermic heat pump operation is performed, and the refrigerant in the refrigerant flow path 20 and the hot water in the hot water flow path 40 circulate as shown by a thick solid line in FIG.

  The controller 10 closes the first open / close valve 29 and the third open / close valve 31 and opens the second open / close valve 30. As a result, the refrigerant that has been compressed by the compressor 21 to a high temperature flows to the water-cooled condenser 22.

  The refrigerant that has flowed to the water-cooled condenser 22 is heated to a low temperature by heating the hot water inside the water-cooled condenser 22, and then cooled to low temperature through the first expansion valve 27. , Flows to the outdoor heat exchanger 23. The refrigerant that has flowed to the outdoor heat exchanger 23 is heated by exchanging heat with the outside air introduced into the outdoor heat exchanger 23, and then flows to the accumulator 26 through the second on-off valve 30 as it is. Gas-liquid separation. Then, the gaseous refrigerant out of the refrigerant gas-liquid separated by the accumulator 26 flows to the compressor 21 again.

  On the other hand, the hot water heated by the refrigerant in the water-cooled condenser 22 circulates and flows to the heater core 42 to heat the air around the heater core 42. The heated air is used as heating air by flowing to the downstream side of the HVAC unit 5. In addition, when the refrigerant cannot sufficiently heat the hot water with the water-cooled condenser 22, the hot water may be heated by operating the auxiliary heater 43 in combination with the outside air endothermic heat pump operation or independently.

<Cooling mode>
Next, the cooling mode will be described with reference to FIG. In the cooling mode, the refrigerant in the refrigerant flow path 20 circulates as shown by a thick solid line in FIG.

  The controller 10 closes the second opening / closing valve 30 and opens the first opening / closing valve 29 and the third opening / closing valve 31. As a result, the refrigerant compressed to high temperature and high pressure by the compressor 21 passes through the first on-off valve 29 and flows to the outdoor heat exchanger 23 as it is.

  The refrigerant that has flowed to the outdoor heat exchanger 23 is cooled by exchanging heat with the outside air introduced into the outdoor heat exchanger 23, and then separated through the liquid tank 24. In the double pipe 60 connected to the downstream side of the liquid tank 24, liquid refrigerant out of the refrigerant separated in the liquid tank 24 flows.

  In the double pipe 60, the liquid refrigerant flowing upstream of the second expansion valve 28 is a high-pressure fluid, and is separated into gas and liquid in the liquid tank 24, so that the degree of supercooling is substantially 0 ° C. It has become. On the other hand, the gaseous refrigerant that circulates downstream of the second expansion valve 28 is a low-pressure fluid that is decompressed and expanded when passing through the second expansion valve 28, and is warmed and evaporated by air when passing through the evaporator 25. ing.

  Since the gaseous refrigerant evaporated by the evaporator 25 is at a lower pressure than the liquid refrigerant separated in the liquid tank 24 by the liquid tank 24, based on the saturation temperature characteristic of the refrigerant, the saturated liquid is used until a predetermined superheat degree is exceeded. The temperature is lower than that of the liquid refrigerant in the state.

  Therefore, when circulating through the double pipe 60, the liquid refrigerant is excessively cooled by the gaseous refrigerant by exchanging heat with the low-temperature gaseous refrigerant. The excessively cooled liquid refrigerant changes from a saturated liquid state to a supercooled state having a supercooling degree. The liquid refrigerant that has been supercooled when flowing through the double pipe 60 is decompressed and expanded through the second expansion valve 28, and then becomes a lower temperature and flows to the evaporator 25.

  The liquid refrigerant flowing to the evaporator 25 evaporates by exchanging heat with the air passing through the evaporator 25 and being heated, and is converted into a gaseous refrigerant and led to the double pipe 60 again. At this time, since the liquid refrigerant is excessively cooled until it reaches a supercooled state, the air passing through the evaporator 25 can be further cooled.

  The refrigerant evaporated by the heat exchange in the evaporator 25 to become a gaseous refrigerant is led to the double pipe 60 again, and cools the liquid refrigerant upstream of the second expansion valve 28. The gaseous refrigerant is heated by the liquid refrigerant and then flows again to the compressor 21 via the accumulator 26 and is compressed. At this time, the gaseous refrigerant is heated by the liquid refrigerant to be in a superheated state having a superheat degree.

  The air cooled by the refrigerant in the evaporator 25 is used as cooling air by flowing to the downstream side of the HVAC unit 5.

  It is also possible to obtain dehumidified air by cooling the air with the evaporator 25 to condense and remove water vapor in the air and then reheating with the heater core 42 (dehumidifying mode).

  Next, with reference to FIGS. 4 to 8B, the configuration of the double tubes 60, 260, 360, and 460 according to the first to fourth embodiments of the present invention and the manufacturing method thereof will be described.

(First embodiment)
First, the double pipe 60 according to the first embodiment of the present invention will be described mainly with reference to FIGS. 4, 5 </ b> A, and 5 </ b> B.

  The double pipe 60 includes an inner pipe 62 through which a gaseous refrigerant (gaseous fluid) flows, and an outer pipe through which the inner pipe 62 passes through the inner circumference and the liquid refrigerant (liquid fluid) flows between the inner pipe 62. 63. Inside the inner pipe 62, a gas flow 20a is formed. Between the inner tube 62 and the outer tube 63, an outer flow path 20b through which the liquid refrigerant flows is formed.

  A low-pressure gaseous refrigerant that flows from the evaporator 25 to the accumulator 26 in the refrigerant flow path 20 flows through the inner flow path 20a. A high-pressure liquid refrigerant flowing from the liquid tank 24 of the refrigerant flow path 20 to the second expansion valve 28 flows through the outer flow path 20b (see FIG. 1). Thereby, heat exchange via the inner pipe 62 is performed between the gaseous refrigerant flowing in the inner flow path 20a and the liquid refrigerant flowing in the outer flow path 20b.

  The inner tube 62 includes a tube member 64 formed in a cylindrical shape, a spiral member 65 that guides the flow of a gaseous fluid through the inner periphery of the tube member 64, and a part of the spiral member 65 having an enlarged diameter. And an enlarged-diameter portion 65b that is in pressure contact with the inner periphery of the pipe member 64. The inner pipe 62 is formed thinner than the outer pipe 63 in order to improve the heat exchange efficiency between the gaseous refrigerant and the liquid refrigerant.

  The spiral member 65 is formed of a plate-shaped metal plate having the same width as the inner diameter of the tube member 64. The spiral member 65 is formed by supporting one end of the plate-shaped metal plate in the longitudinal direction and rotating the other end about the longitudinal axis to be twisted. When the spiral member 65 is twisted, both ends in the width direction are formed so as to form a spiral in the longitudinal direction. The spiral member 65 is slightly reduced in diameter than the inner diameter of the tube member 64 and can be inserted into the tube member 64. . Thus, the spiral member 65 is formed separately from the tube member 64 and then inserted into the tube member 64 so as to extend in the longitudinal direction.

  The enlarged diameter portion 65 b is formed by compressing the axial end portion 65 a of the spiral member 65 in the plate thickness direction over the entire width direction of the spiral member 65. The enlarged diameter portion 65b is formed at each end portion in the width direction of the axial end portion 65a. The enlarged diameter portion 65 b defines the position of the spiral member 65 in the longitudinal direction with respect to the tube member 64 by being pressed against the inner peripheral surface of the tube member 64 of the inner tube 62. In addition to the press contact, a part of the enlarged diameter portion 65b may be fitted by pressing the inner periphery of the pipe member 64.

  As described above, the spiral member 65 is attached to the pipe member 64 when the diameter-expanded portion 65 b is in pressure contact with the inner periphery of the pipe member 64. Therefore, since the flow path of the gaseous fluid is not narrowed to attach the spiral member 65, the spiral member 65 can be fixed to the tube member 64 without changing the flow path resistance.

  The outer pipe 63 includes a tubular member 66 formed in a cylindrical shape, a liquid refrigerant inlet 63a that takes in a liquid refrigerant that flows through the outer flow path 20b from the outside, and a liquid refrigerant that flows the liquid refrigerant that flows through the outer flow path 20b to the outside. And an outlet 63b. The outer tube 63 is formed thicker than the inner tube 62 in order to ensure the pressure resistance of the double tube 60.

  The tube member 66 is formed concentrically with the tube member 64 of the inner tube 62. The tube member 66 is formed with a larger diameter than the tube member 64 of the inner tube 62. As a result, the outer flow path 20 b is formed between the pipe member 66 and the pipe member 64.

  The liquid refrigerant inlet 63a and the liquid refrigerant outlet 63b are formed facing the outside of the inner pipe 62. The liquid refrigerant inlet 63a is provided facing the downstream side of the inner flow path 20a. The liquid refrigerant outlet 63b is provided facing the upstream side of the inner flow path 20a as compared with the liquid refrigerant inlet 63a. Therefore, the liquid refrigerant that is supplied from the liquid refrigerant inlet 63a and flows through the outer flow path 20b and discharged from the liquid refrigerant outlet 63b flows in a direction opposite to the gaseous refrigerant flowing through the inner flow path 20a. Therefore, the amount of heat exchange between the liquid refrigerant and the gaseous refrigerant can be increased.

  Next, a method for manufacturing the double pipe 60 will be described.

  First, the spiral member 65 that guides the flow of the gaseous fluid in a spiral manner is inserted through the tubular member 64 formed in a cylindrical shape (insertion step).

  Subsequently, a part of the spiral member 65 is enlarged in diameter to form a pair of enlarged diameter portions 65b, and is pressed against the inner periphery of the pipe member 64 (increase diameter process). At this time, the axial end portion 65a of the spiral member 65 is compressed and expanded in the plate thickness direction of the spiral member 65 to form the expanded diameter portion 65b.

  Specifically, as shown in FIGS. 5A and 5B, the axial end portion 65 a of the spiral member 65 is sandwiched and compressed by a pair of compression processing jigs 91. As a result, the axial end portion 65a of the spiral member 65 is expanded in diameter toward the outer periphery by the amount crushed in the thickness direction, so that the expanded diameter portion 65b is formed. The spiral member 65 is fixed to the pipe member 64 when the diameter-expanded portion 65 b is in pressure contact with the inner periphery of the pipe member 64.

  Finally, the inner tube 62 is inserted into the outer periphery of the outer tube 63, and both end portions 66a of the tube member 66 in the outer tube 63 are caulked (see FIG. 4). Thereby, the inner pipe 62 is fixed to the outer pipe 63, and the double pipe 60 is completed.

  According to the above 1st Embodiment, there exists an effect shown below.

  In the double tube 60, a part of the spiral member 65 is expanded in diameter to form an expanded diameter portion 65b. The spiral member 65 is attached to the pipe member 64 when the diameter-expanded portion 65 b is pressed against the inner periphery of the pipe member 64. Therefore, since the flow path of the gaseous fluid is not narrowed to attach the spiral member 65, the spiral member 65 can be fixed to the tube member 64 without changing the flow path resistance.

(Second Embodiment)
Hereinafter, with reference to FIG. 6A and FIG. 6B, the double pipe 260 which concerns on the 2nd Embodiment of this invention is demonstrated. In each embodiment shown below, it demonstrates centering on a different point from 1st Embodiment, the same code | symbol is attached | subjected to the structure which has the same function, and description is abbreviate | omitted. For example, in each embodiment shown below, since the structure of the outer tube | pipe 63 is the same as 1st Embodiment, description is abbreviate | omitted.

  The double pipe 260 includes an inner pipe 262 through which a gaseous refrigerant flows, and an outer pipe 63 through which the inner pipe 262 passes through the inner periphery and a liquid refrigerant flows between the inner pipe 262.

  The inner tube 262 includes a tube member 64 formed in a cylindrical shape, a spiral member 265 that guides the flow of gaseous fluid through the inner periphery of the tube member 64, and a part of the spiral member 265 has an enlarged diameter. And an enlarged-diameter portion 265b that is in pressure contact with the inner periphery of the pipe member 64.

  The enlarged diameter portion 265b is formed by locally compressing both end portions in the width direction of the axial end portion 265a of the spiral member 265 in the plate thickness direction. The enlarged diameter portion 265b is formed at both ends in the width direction of the axial end portion 265a. The enlarged diameter portion 265 b is in pressure contact with the inner peripheral surface of the tube member 64 of the inner tube 62, thereby defining the longitudinal position of the spiral member 265 with respect to the tube member 64.

  Next, a method for manufacturing the double pipe 260 will be described.

  First, the spiral member 265 that guides the flow of the gaseous fluid in a spiral manner is inserted through the cylindrical tube member 64 (insertion step).

  Subsequently, a part of the spiral member 265 is expanded in diameter to form a pair of expanded diameter portions 265b, and is brought into pressure contact with the inner periphery of the pipe member 64 (diameter expansion step). At this time, both end portions in the width direction of the axial end portion 265a of the spiral member 265 are compressed in the plate thickness direction of the spiral member 265 to expand the diameter, thereby forming the expanded diameter portion 265b.

  Specifically, as shown in FIGS. 6A and 6B, both ends in the width direction of the axial end portion 65a of the spiral member 65 are sandwiched by a pair of compression processing jigs 291 respectively, and locally in the plate pressure direction. Compress. As a result, both end portions in the width direction of the axial end portion 265a of the spiral member 265 are expanded to the outer circumference by the amount crushed in the thickness direction, so that the expanded diameter portion 265b is formed. The spiral member 265 is fixed to the tube member 64 when the diameter-enlarged portion 265b is in pressure contact with the inner periphery of the tube member 64.

  Finally, the inner tube 262 is inserted into the outer periphery of the outer tube 63, and both ends 66a of the tube member 66 in the outer tube 63 are caulked (see FIG. 4). Thereby, the inner pipe 262 is fixed to the outer pipe 63, and the double pipe 260 is completed.

  According to the second embodiment described above, the same effect as that of the first embodiment is obtained, and both end portions in the width direction of the axial end portion 265a of the spiral member 265 are sandwiched between the pair of compression processing jigs 291, respectively. Therefore, the pressing force by the compression processing jig 291 can be reduced as compared with the first embodiment. Therefore, the processing cost can be reduced, for example, the equipment used for processing can be reduced.

(Third embodiment)
Hereinafter, a double pipe 360 according to a third embodiment of the present invention will be described with reference to FIGS. 7A and 7B.

  The double pipe 360 includes an inner pipe 362 through which a gaseous refrigerant flows, and an outer pipe 63 through which the inner pipe 362 passes through the inner periphery and a liquid refrigerant flows between the inner pipe 362.

  The inner pipe 362 includes a cylindrical pipe member 64, a helical member 365 that guides the flow of the gaseous fluid through the inner periphery of the pipe member 64, and a part of the helical member 365 has an enlarged diameter. And an enlarged diameter portion 365b that is pressed against the inner periphery of the pipe member 64.

  The enlarged diameter portion 365b is formed by locally compressing both ends in the width direction of the axial end portion 365a of the spiral member 365 in the longitudinal direction (axial direction). The enlarged diameter portion 365b is formed at both ends in the width direction of the axial end portion 365a. The enlarged diameter portion 365b defines the position of the spiral member 365 in the longitudinal direction with respect to the tube member 64 by being pressed against the inner peripheral surface of the tube member 64 of the inner tube 62.

  Next, a method for manufacturing the double pipe 360 will be described.

  First, the spiral member 365 that guides the flow of the gaseous fluid in a spiral manner is inserted through the tubular member 64 formed in a cylindrical shape (insertion step).

  Subsequently, a part of the spiral member 365 is expanded in diameter to form a pair of expanded diameter portions 365b, and is brought into pressure contact with the inner periphery of the pipe member 64 (a diameter expansion process). At this time, both end portions in the width direction of the axial end portion 365a of the spiral member 365 are compressed in the longitudinal direction of the spiral member 365 to expand the diameter, thereby forming the expanded diameter portion 365b.

  Specifically, as shown in FIGS. 7A and 7B, the axial end portion 65 a of the spiral member 65 is sandwiched and fixed by a pair of fixing jigs 392. And the both ends of the width direction in the axial direction edge part 65a of the spiral member 65 are each pressed by a pair of compression processing jig | tool 391, and are compressed locally to a longitudinal direction. As a result, both end portions in the width direction of the axial end portion 365a of the spiral member 365 are expanded to the outer circumference by the amount crushed in the longitudinal direction, so that the expanded diameter portion 365b is formed. The spiral member 365 is fixed to the tube member 64 by the enlarged diameter portion 365b being pressed against the inner periphery of the tube member 64.

  Finally, the inner tube 362 is inserted into the outer periphery of the outer tube 63, and both end portions 66a of the tube member 66 in the outer tube 63 are caulked (see FIG. 4). Thereby, the inner pipe 362 is fixed to the outer pipe 63, and the double pipe 360 is completed.

  According to the third embodiment described above, the same effect as that of the first embodiment is obtained, and similarly to the second embodiment, the axial end portion 365a of the spiral member 365 is formed by the pair of compression processing jigs 391. Since both end portions in the width direction are pressed and compressed locally, the pressing force by the compression processing jig 391 can be reduced as compared with the first embodiment. Therefore, the processing cost can be reduced, for example, the equipment used for processing can be reduced.

(Fourth embodiment)
Hereinafter, with reference to FIG. 8A and FIG. 8B, the double tube 460 which concerns on the 4th Embodiment of this invention is demonstrated.

  The double pipe 460 includes an inner pipe 462 through which a gaseous refrigerant flows, and an outer pipe 63 through which the inner pipe 462 passes through the inner periphery and a liquid refrigerant flows between the inner pipe 462.

  The inner tube 462 includes a tube member 64 formed in a cylindrical shape, a spiral member 465 that guides the flow of the gaseous fluid in a spiral manner through the inner periphery of the tube member 64, and a part of the spiral member 465 has an enlarged diameter. And an enlarged diameter portion 465b that press-contacts the inner periphery of the pipe member 64.

  The enlarged diameter portion 465b is formed by compressing the entire spiral member 465 in the longitudinal direction (axial direction) from both ends. The enlarged diameter portion 465b is formed over the entire longitudinal direction of the spiral member 465. The enlarged diameter portion 465 b is in pressure contact with the inner peripheral surface of the tube member 64 of the inner tube 62, thereby defining the longitudinal position of the spiral member 465 with respect to the tube member 64.

  Next, a method for manufacturing the double tube 460 will be described.

  First, the spiral member 465 that guides the flow of the gaseous fluid in a spiral shape is inserted through the cylindrical tube member 64 (insertion step).

  Subsequently, the entire longitudinal direction of the spiral member 465 is expanded to form a diameter-expanded portion 465b, which is pressed against the inner periphery of the pipe member 64 (a diameter-expanding step).

Specifically, as shown in FIG. 8A, a pair of compression processing jigs 491 are arranged at both ends in the longitudinal direction of the spiral member 65, and the spiral member 65 is pressed so as to be compressed from both ends in the longitudinal direction. Thus, as shown in FIGS. 8A and 8B, the helical member 65 is shorter to a length L _B is compressed from the length L _A. Further, as shown in FIG. 8B, the entire spiral member 465 is expanded in diameter to the outer periphery by the amount compressed in the longitudinal direction, so that an expanded diameter portion 465b is formed. The spiral member 465 is fixed to the tube member 64 when the diameter-expanded portion 465b is in pressure contact with the inner periphery of the tube member 64.

  Finally, the inner tube 462 is inserted into the outer periphery of the outer tube 63, and both end portions 66a of the tube member 66 in the outer tube 63 are caulked (see FIG. 4). Thereby, the inner tube 462 is fixed to the outer tube 63, and the double tube 460 is completed.

  According to the fourth embodiment described above, the same effects as those of the first embodiment can be obtained, and the enlarged diameter portion 465b is formed in the entire longitudinal direction of the spiral member 465. Therefore, the spiral member 465 is used as the tube member 64. On the other hand, it can be firmly fixed.

  In the first to third embodiments, a part of the spiral members 65, 265, and 365 is enlarged to form the enlarged diameter portions 65b, 265b, and 365b, whereas the fourth embodiment. Then, the diameter of the entire spiral member 465 is expanded to form the expanded diameter portion 465b. As described above, the enlarged diameter portions 65b, 265b, 365b, and 465b are formed by expanding at least a part of the spiral members 65, 265, 365, and 465.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  Moreover, the manufacturing method of the double tube | pipe which concerns on 1st-4th embodiment can be combined suitably. Therefore, for example, after the helical member is compressed in the plate pressure direction according to the first or second embodiment, the expanded member may be formed by further compressing the helical member in the axial direction according to the third embodiment.

DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Refrigeration cycle 20 Refrigerant flow path 20a Inner flow path 20b Outer flow path 60,260,360,460 Double pipe (internal heat exchanger)
62, 262, 362, 462 Inner tube 63 Outer tube 64 Tube members 65, 265, 365, 465 Spiral members 65a, 265a, 365a Axial end portions 65b, 265b, 365b, 465b Expanded diameter portion

Claims (10)

A double pipe having an inner pipe through which a gaseous fluid flows, and an outer pipe through which the inner pipe passes through an inner circumference and a liquid fluid flows between the inner pipe,
The inner tube is
A tubular member formed in a cylindrical shape;
A spiral member that guides the flow of the gaseous fluid in a spiral manner through the inner periphery of the tube member;
A double pipe comprising: a diameter-expanded portion having at least a part of the spiral member whose diameter is expanded and being in pressure contact with an inner periphery of the tube member. The double pipe according to claim 1,
The double diameter tube is characterized in that the enlarged diameter portion is formed by compressing an axial end portion of the spiral member in a plate thickness direction of the spiral member. The double pipe according to claim 1,
The double diameter tube is characterized in that the enlarged diameter portion is formed by locally compressing an axial end portion of the spiral member in a thickness direction of the spiral member. The double pipe according to claim 1,
The double diameter tube is characterized in that the enlarged diameter portion is formed by locally compressing an axial end of the helical member in the axial direction of the helical member. The double pipe according to claim 1,
The double diameter tube is characterized in that the enlarged diameter portion is formed by compressing the spiral member from both ends in the axial direction. A method of manufacturing a double tube, comprising: an inner tube through which a gaseous fluid flows; and an outer tube through which the inner tube passes through an inner periphery and a liquid fluid flows between the inner tube and the inner tube. Because
An insertion step of inserting a spiral member that guides the flow of the gaseous fluid in a spiral manner into a tubular member formed in a cylindrical shape;
A diameter expanding step of expanding at least a part of the spiral member and press-contacting with an inner periphery of the tube member. It is a manufacturing method of the double pipe according to claim 6,
In the diameter expansion step, the axial end portion of the spiral member is compressed in the plate thickness direction of the spiral member to expand the diameter. It is a manufacturing method of the double pipe according to claim 6,
In the diameter expansion step, the axial end of the spiral member is locally compressed in the plate thickness direction of the spiral member to expand the diameter. It is a manufacturing method of the double pipe according to claim 6,
In the diameter expansion step, the axial end portion of the spiral member is locally compressed in the axial direction of the spiral member to expand the diameter, and the method for manufacturing a double pipe. It is a manufacturing method of the double pipe according to claim 6,
In the diameter expansion step, the spiral member is compressed from both end portions in the axial direction to expand the diameter, and the method for producing a double pipe.

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