JP2007187413A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger which effectively prevents main piping used for the heat exchanger, from being damaged due to the initiation of a crack caused by refrigerant pressure in the heat exchanger using a refrigerant of high pressure. <P>SOLUTION: In the heat exchanger (a gas cooler 24), refrigerant piping 3 of meandering shape is composed of the main piping 32 having a straight pipe part, and curved bend piping 36 connecting the ends 33 of the main piping 32 to each other. The end 37 of the bent piping 36 is inserted in the end 33 of the main pipe 32 and welded. The outer diameter of the end 37 of the bend piping 36 is smaller than the outer diameter of the end 33 of the main piping 32. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat exchanger in which a meandering refrigerant pipe is constituted by a main pipe having a straight pipe portion and a curved bend pipe that interconnects ends of the main pipe.

  Conventionally, this kind of heat exchanger is composed of a plurality of heat exchange fins arranged at a predetermined interval and a meandering refrigerant pipe penetrating through the heat exchange fins. Then, when assembling the heat exchanger, first, a plurality of heat exchange fins with holes drilled in advance are inserted into a plurality of straight tubular main pipes at predetermined intervals, and then a tube expansion jig is inserted into the main pipe. Is pushed from the inside. As a result, the main pipe expands to increase its diameter and comes into contact with the inside of the holes formed in the heat exchange fin and the tube sheet, and the main pipe is fixed to the heat exchange fin and the tube sheet. A tube plate having a thickness greater than that of the heat exchange fins and having strength is inserted at both ends of the plurality of heat exchange fins.

  Next, the end portion of the U-shaped bent pipe is inserted into the end portion of the main pipe, and a meandering refrigerant pipe is constructed by welding and fixing both with a brazing material (welding material). there were. The main pipe and the bend pipe are usually pipes having the same outer diameter. And when inserting the bend pipe into the end of the main pipe, after the main pipe is inserted into the holes of the heat exchange fins and the tube plate, a pipe expansion jig is inserted into the main pipe and expanded from the inside. After (primary expansion) was performed, a bend pipe was inserted (see Patent Document 1).

  That is, as shown in FIG. 13, the conventional heat exchanger 124 includes a tube plate 127 in which holes (not shown) are previously drilled, a plurality of heat exchange fins 126, a tube plate (not shown), and a plurality of main pipes 132 (see FIG. 13). 13, the main pipe 132 is inserted into the main pipe 132 at a predetermined interval. After that, a pipe expansion jig (not shown) is inserted into the main pipe 132 and is expanded from the inside to perform primary pipe expansion. Thereby, the main piping 132 is fixed to the heat exchange fins 126 and the tube plate 127.

  Next, a tube expansion jig (not shown) is inserted from the end 133 of the main pipe 132 (the side away from the heat exchange fin 126 with the tube plate 127 as a boundary), and is expanded from the inside to perform secondary tube expansion. The secondary expanded pipe is formed from a position separated from the tube plate 27 by a predetermined dimension to the tip of the end portion 133, and a stepped portion 134 is formed at the boundary between the primary expanded section and the secondary expanded section. Thereafter, the end portion 133 (tip portion) of the main pipe 132 is flared. Then, the end portion 137 of the bend pipe 136 is inserted from the flare portion 132B in which the main pipe 132 is flared, and is inserted until the tip of the end portion 137 of the bend pipe 36 contacts the stepped portion 134. Next, a brazing material (welding material) (not shown) is filled in the flare portion 132B of the main pipe 132, the brazing material is melted by a welding machine such as a burner, and the end 133 of the main pipe 132 and the bend pipe 136 are welded. It was.

Here, chlorofluorocarbon refrigerants such as chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC) and the like have been generally used. In the heat exchanger 124 using such a refrigerant, the main pipe 132 has an outer diameter of 7.94 mm, a wall thickness of 0.31 mm, and an inner diameter of 7.32 mm, and the inner diameter after primary expansion is 7.72 mm. The inner diameter after the secondary expansion is 8.10 mm. Further, the bend pipe 136 had an outer diameter of 7.94 mm and a wall thickness of 0.41 mm. In the heat exchanger using carbon dioxide (CO ₂ equipment in the figure), the main pipe 132 has an outer diameter of 7.94 mm, a wall thickness of 1.00 mm, and an inner diameter of 5.94 mm because of high pressure. ing. The inner diameter of the main pipe 132 after the primary expansion is 6.34 mm, the inner diameter after the secondary expansion is 8.10 mm, the outer diameter of the bend pipe 136 is 7.94 mm, and the wall thickness is 1.40 mm. Was configured.

The bend pipe 136 having such dimensions is connected and fixed to the main pipe 132 to form a meandering refrigerant pipe 130. Then, when the brazing material is melted by the welding machine and the end portion 133 of the main pipe 132 and the bend pipe 136 are welded, the main pipe 132 is affected by heat and the strength is deteriorated (FIG. 13 bracket B portion B). ). Therefore, there is a concept of increasing the thickness of the main piping and the bend piping, but increasing the thickness increases the cost.
JP-A-10-220986

  As described above, in the conventional heat exchanger, since it is difficult to increase the thickness of the main pipe and the bend pipe, the main pipe that is expanded twice by the primary expansion pipe and the secondary expansion pipe is Even the heat at the time of welding with the bend pipe decreases the strength in the vicinity of the weld. For this reason, there has been a problem that if the carbon dioxide or the like in which the heat exchanger has a high pressure is used as the refrigerant, the main pipe is cracked and broken.

  Further, when the end of the bend pipe is inserted into the end of the main pipe, the processing work required for expanding the end of the main pipe becomes complicated and there is a problem that the production cost increases.

  The present invention has been made to solve the problems of the related art, and even when a high-pressure refrigerant such as carbon dioxide is used in a heat exchanger, the main pipe is damaged due to cracks or the like. It aims at providing the heat exchanger which can prevent effectively.

  That is, the heat exchanger of the present invention comprises a main pipe having a straight pipe portion and a curved bend pipe connecting the ends of the main pipe to each other to form a meandering refrigerant pipe. The end of the bend pipe is inserted into the end of the main pipe and welded, and the outer diameter of the bend pipe end is smaller than the outer diameter of the main pipe end.

  In the heat exchanger according to the second aspect of the present invention, the outer diameter of the bend pipe is smaller than the outer diameter of the end portion of the main pipe as a whole.

  According to a third aspect of the present invention, in the heat exchanger according to the first or second aspect, the outer diameter of the end portion of the bend pipe is smaller than the inner diameter of the end portion of the main pipe.

  According to a fourth aspect of the present invention, the heat exchanger according to the third aspect is characterized in that the outer diameter of the bend pipe is smaller than the inner diameter of the end portion of the main pipe as a whole.

  According to a fifth aspect of the present invention, in addition to the third or fourth aspect, the bend pipe is provided with a protrusion that contacts the end of the main pipe when inserted into the main pipe. It is characterized by being.

  A heat exchanger according to a sixth aspect of the present invention includes, in addition to any one of the first to fifth aspects, a tube sheet that holds an end of the main pipe, and the bend pipe includes the main pipe and the tube sheet. It is inserted to the contact position.

  According to a seventh aspect of the present invention, there is provided a heat exchanger comprising a main pipe having a straight pipe portion and a curved bend pipe that interconnects ends of the main pipe to form a meandering refrigerant pipe. The end of the bend pipe is squeezed inward, the end of the main pipe is flared, and the end of the bend pipe is welded in contact with the end of the main pipe. It is characterized by being.

  According to the first aspect of the present invention, in a heat exchanger in which a meandering refrigerant pipe is constituted by a main pipe having a straight pipe portion and a curved bend pipe connecting ends of the main pipe to each other, the bend pipe The end of the main pipe is inserted into the end of the main pipe and welded, and the outer diameter of the end of the bend pipe is smaller than the outer diameter of the end of the main pipe. The rate of expanding the main pipe end can be reduced or made zero.

  As a result, the strength of the welded portion between the main pipe end and the bend pipe can be improved as compared with the conventional case. For example, when used in a refrigerant cycle in which the high pressure side such as carbon dioxide has an extremely high pressure. However, inconveniences that cause breakage such as cracks can be avoided in advance. In addition, since it is possible to simplify the processing work required for expanding the end of the main piping, it is possible to reduce the production cost.

  In the invention of claim 2, since the outer diameter of the bend pipe is made smaller than the outer diameter of the end portion of the main pipe as a whole, it is not necessary to reduce the diameter of the end portion of the bend pipe, and the pressure resistance strength is increased. Due to the improvement, the thickness of the bend pipe itself can be reduced, so that the heat capacity of the bend pipe is reduced and the weldability is improved. In addition, the bend piping itself is improved in productivity as the thickness is reduced, and the material cost can be reduced.

  In the invention of claim 3, in addition to each of the above inventions, the outer diameter of the end of the bend pipe is smaller than the inner diameter of the end of the main pipe, so the bend pipe is inserted without expanding the end of the main pipe, It becomes possible to weld, and it becomes possible to further improve the strength and weldability.

  In the invention of claim 4, in the above, the outer diameter of the bend pipe is made smaller than the inner diameter of the end portion of the main pipe as a whole, so that further improvement of productivity and reduction of cost can be achieved. Is.

  In the invention of claim 5, in addition to the invention of claim 3 or claim 4, the bend pipe is formed with a protrusion that comes into contact with the end of the main pipe when inserted into the main pipe. When the outer diameter of the bend pipe is smaller than the entire inner diameter of the pipe, the insertion dimension of the bend pipe can be determined at the protrusion, which can further improve productivity. It becomes like this.

  In the invention of claim 6, in addition to each of the above inventions, a pipe plate for holding the end of the main pipe is provided, and the bend pipe is inserted to the contact position between the main pipe and the pipe plate. The welded portion between the main pipe and the bend pipe can be reinforced by the plate, and the strength can be further improved.

  According to a seventh aspect of the present invention, in a heat exchanger comprising a meandering refrigerant pipe composed of a main pipe having a straight pipe portion and a curved bend pipe interconnecting ends of the main pipe, the bend pipe The end of the main pipe is squeezed inward, the end of the main pipe is flared, and the end of the bend pipe is welded in contact with the end of the main pipe. There is no need to perform pipe expansion work at the end of the main pipe.

  As a result, the strength of the welded portion between the main pipe end and the bend pipe can be improved as compared with the conventional case. For example, when used in a refrigerant cycle in which the high pressure side such as carbon dioxide has an extremely high pressure. However, inconveniences that cause breakage such as cracks can be avoided in advance. In addition, since only the flare processing is required for processing the end portion of the main pipe, the production cost can be reduced.

  The present invention greatly improves the strength of the joint between the main pipe and the bend pipe, and even when a refrigerant having a high pressure such as carbon dioxide is used for the heat exchanger, the main pipe is damaged due to cracks or the like. It is characterized by preventing. The purpose of preventing the main pipe from being damaged due to cracks, etc. was realized with a simple structure in which the outer diameter of the end of the bend pipe is made smaller than the outer diameter of the end of the main pipe.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of an embodiment provided with the heat exchanger of the present invention, FIG. 2 is a perspective view of the heat exchanger of the present invention as viewed from one side, and FIG. 3 is the other side of the heat exchanger of FIG. The perspective view seen from each is shown.

  In the figure, reference numeral 1 denotes an internal intermediate pressure multistage (two-stage) compression rotary compressor that uses carbon dioxide as a refrigerant. The rotary compressor 1 includes a cylindrical sealed container 2 made of a steel plate, and an interior of the sealed container 2. An electric element 4 disposed on the upper side of the space, a first rotary compression element 10 (first stage) disposed on the lower side of the electric element 4 and driven by the rotating shaft 6 of the electric element 4; The rotary compression mechanism unit 14 is composed of the second rotary compression element 12 (second stage).

  The sealed container 2 includes a container main body 2A that houses the electric element 4 and the rotary compression mechanism section 14, and a substantially bowl-shaped end cap (lid body) 2B that closes an end opening (upper opening) of the container main body 2A. It is configured. A terminal (wiring is omitted) 16 for supplying power to the electric element 4 is attached to the center of the upper surface of the end cap 2B.

  One end of a refrigerant introduction pipe 18 for introducing refrigerant gas is inserted and connected to the second rotary compression element 12, and one end of the refrigerant introduction pipe 18 is connected to a suction passage (not shown) of the second rotary compression element 12. Z)). The other end of the refrigerant introduction pipe 18 passes through the outside of the sealed container 2 and communicates with the sealed container 2. One end of a refrigerant introduction pipe 20 for introducing refrigerant gas is inserted and connected to the first rotary compression element 10, and one end of the refrigerant introduction pipe 20 is connected to a suction passage (not shown) of the first rotary compression element 10. Z)). A refrigerant discharge pipe 22 is inserted and connected to the second rotary compression element 12, and one end of the refrigerant discharge pipe 22 communicates with a discharge silencer chamber (not shown).

  And the rotary compressor 1 comprised in this way is used for the refrigerant circuit provided with heat exchangers, such as a refrigerator, a room air conditioner, a car air conditioner, or a packaged air conditioner. That is, the refrigerant discharge pipe 22 of the rotary compressor 1 is connected to the inlet of the gas cooler 24, the pipe exiting the gas cooler 24 reaches the inlet of the evaporator 28 through the expansion valve 25 as a decompression device, and the outlet of the evaporator 28 is the refrigerant. It is connected to the introduction pipe 20. The gas cooler 24 and the evaporator 28 correspond to the heat exchanger of the present invention. Hereinafter, the heat exchanger will be described with the gas cooler 24.

  Next, the operation will be described. The rotary compressor 1 is energized to the electric element 4 via the terminal 16 and wiring (not shown), and the electric element 4 is activated. Due to the activation of the electric element 4, the low-pressure (3 to 4 MPaG) refrigerant gas sucked into the low-pressure chamber side of the first rotary compression element 10 from the refrigerant introduction pipe 20 is compressed there to be intermediate pressure (8 to 10 MPaG). It becomes. The intermediate-pressure refrigerant gas compressed by the first rotary compression element 10 passes through a communication path (not shown) and an intermediate discharge pipe into the sealed container 2 (between the second rotary compression element 12 and the electric element 4 side). Discharged.

  Then, the refrigerant gas discharged into the sealed container 2 is sucked into the low pressure chamber side of the second rotary compression element 12 via the refrigerant introduction pipe 18. The refrigerant gas sucked into the low-pressure chamber side of the second rotary compression element 12 is compressed there to become high-temperature and high-pressure (12 to 13 MPaG) refrigerant gas, and enters the gas cooler 24 from the high-pressure chamber side via the refrigerant discharge pipe 22. Flow into.

  The refrigerant gas that has flowed into the gas cooler 24 radiates heat therein, is decompressed by the expansion valve 25, and then flows into the evaporator 28. The refrigerant flowing into the evaporator 28 evaporates there, and at that time absorbs heat from the surroundings, thereby exerting a cooling action in a refrigerator, a room air conditioner, a car air conditioner, a packaged air conditioner, or the like. The refrigerant exiting the evaporator 28 repeats the cycle of being sucked into the first rotary compression element 10 from the refrigerant introduction pipe 20.

  By the way, the pressure of the refrigerant gas discharged from the internal intermediate pressure two-stage compression rotary compressor 1 using carbon dioxide as a refrigerant and flowing into the gas cooler 24 is as high as 12 to 13 MPaG. When the pressure of this high-pressure refrigerant gas is compared with the pressure of refrigerant gas discharged from a conventional rotary compressor that does not use carbon dioxide (5 MPaG), there is a pressure difference of more than twice, and there is a crack in the pipe of the gas cooler 24. There was an inconvenience that caused damage. Accordingly, in the present invention, the strength of the gas cooler 24 is increased as described below.

  That is, the gas cooler 24 is made of an aluminum plate as shown in FIGS. 2 and 3, and includes a plurality of heat exchange fins 26... Provided at predetermined intervals and the heat exchange fins 26. The so-called fin tube type heat composed of the tube plates 27 arranged at both ends, and the heat exchange fins 26... And the meandering copper tube refrigerant pipe 30 penetrating the tube plates 27. It consists of an exchanger.

  The refrigerant pipe 30 includes a plurality of main pipes 32... Having straight pipe portions 32A (shown in FIG. 4) that are straight and not curved, and main pipes 32 outside the tube plates 27 on both sides. It is comprised from the bend piping 36 which connects the edge part 33 of the piping 32 mutually. In the embodiment, the main pipe 32 extending from the tube plate 27 to the side away from the heat exchange fin 26 is referred to as an end portion 33 of the main pipe 32.

  As shown in FIG. 4, the main pipe 32 is formed in a U shape by curving a substantially central portion of a pipe extending in a straight line with a predetermined dimension. Both end portions 33 (tip portions) of the main pipe 32 are flared by a flare processing jig (not shown), and flare portions 32B projecting obliquely outward (in FIG. 4, only one side is a flare portion). 32B is provided), and the flare portion 32B protrudes obliquely by about 1 to 2 mm. Specifically, the main pipe 32 is formed in a cylindrical shape having an outer diameter of 7.94 mm, a wall thickness of 1.00 mm, and an inner diameter of 5.94 mm (shown in the column of the present technology 2 in FIG. 12), and from one end to the other end. It is formed in a straight line having substantially the same thickness, and the central part in the longitudinal direction is curved in a U shape. In addition, the main piping 32 uses what connected the U-shaped bend piping beforehand to the one side of the pipe extended linearly, without forming the center part of the pipe extended linearly in U shape. There is no problem.

  The bend pipe 36 has a curved portion 36A formed in a semicircular arc shape and a predetermined dimension (about 0.5 to 2 times the outer diameter of the bend pipe 36) continuously at both ends of the curved portion 36A. It is formed in a U shape from an end portion 37 (shown in FIG. 5) formed in the shape. The bend pipe 36 has an outer diameter of 6.20 mm and a wall thickness of 1.00 mm, and is formed in a curved cylindrical shape having substantially the same wall thickness from one end to the other end. At a predetermined position of the end portion 37 of the bend pipe 36, there is provided a protrusion 39 that comes into contact with the end portion 33 (tip portion) of the main pipe 32 when inserted into the main pipe 32.

  The protrusions 39 are respectively formed on end portions 37 provided at both ends of the bending portion 36 </ b> A of the bend pipe 36. The projecting portion 39 is provided so as to protrude from the inner side (center side) of the end portion 37 by a predetermined dimension, and when the bend pipe 36 is inserted into the main pipe 32, the end portion 37 of the bend pipe 36 is further increased. Is configured not to enter the end 33 of the main pipe 32. The protrusion 39 may be provided in a hemispherical shape or a cylindrical shape, and a plurality of protrusions 39 may be provided around the end portion 37. Furthermore, the protrusion 39 may be a protrusion protruding around the end 37 in a bowl shape.

  When assembling the gas cooler 24 with the above configuration, first, a plurality of heat exchange fins 26 provided at predetermined intervals, and tube plates 27 provided at both ends of the heat exchange fins 26, A plurality of predetermined holes (not shown) are previously formed in 27. And after both straight pipe | tube parts 32A are inserted in this hole from the edge part 33 of the main piping 32, the pipe expansion jig which is not shown in figure in the main piping 32 is inserted from the edge part 33, and is expanded from the inner side. As a result, the main pipe 32 which has expanded and has a large diameter comes into contact with the inside of the holes formed in the heat exchange fins 26... And the tube plate 27. It is fixed to 27 ... Hereinafter, a state in which the main pipe 32 is pushed and expanded from the inside of the holes formed in the heat exchange fins 26... And the tube plates 27.

  At this time, the main pipe 32 having an inner diameter of 5.94 mm has an inner diameter of about 6.34 mm after the primary expansion, and the outer diameter of the bend pipe 36 is 6.20 mm. The outer diameter of 33 is smaller. That is, the outer diameter of the entire bend pipe 36 constituting the gas cooler 24 (heat exchanger) is formed to be smaller than the outer diameter of the primary pipe 32 end portion 33 that is primarily expanded, and the bend pipe 36 is not expanded. In addition, a straight straight pipe is used simply by bending it into a U-shape. The clearance between the inner diameter of the main pipe 32 expanded primarily and the outer diameter of the bend pipe 36 is about 0.07 mm, which is suitable for welding brazing material (welding material) between the main pipe 32 and the bend pipe 36. It is configured in a gap.

  Next, the end portion 37 of the bend pipe 36 is inserted into the end portion 33 of the main pipe 32 from the flare portion 32B side. The end portion 37 of the bend pipe 36 is inserted into the end portion 33 of the main pipe 32 until the protrusion 39 provided on the end portion 37 comes into contact with the tip end of the main pipe 32 end portion 33 (FIG. 5). . In this case, the length of the end portion 37 of the bend pipe 36 extends to the vicinity of the tube plate 27 or the first to third heat exchange fins close to the tube plate 27.

  That is, the protrusion 39 of the end portion 37 of the bend pipe 36 is merely brought into contact with the end of the end portion 33 of the main pipe 32, and the end of the end portion of the bend pipe 36 passes through the end portion 33 of the main pipe 32. Alternatively, it can be positioned in the vicinity of the first to third heat exchange fins close to the tube plate 27 and determined at that position. Next, a brazing material (welding material) (not shown) is filled in the flare 32B of the main pipe 32, the brazing material is melted by a welding machine such as a burner, and the end 33 of the main pipe 32 and the bend pipe 36 are fixed by welding. Is done. Hereinafter, the melting of the brazing material by a welding machine such as a burner and the fixing of the main pipe 32 and the bend pipe 36 by welding is simply referred to as welding or joining of the main pipe 32 and the bend pipe 36.

  As a result, the bend pipe 36 is connected and fixed to the main pipe 32 to form a meandering refrigerant pipe 30. At this time, since the end portion 33 of the main pipe 32 is heated by welding, the material strength in the vicinity of the weld portion deteriorates, but the tip of the bend pipe 36 end portion 37 is inserted to the tube plate 27, so Even when the end portion 33 (the bracket A in FIG. 5) of the pipe 32 is heated by welding, the strength of the main pipe 32 can be maintained because of the double structure.

  As described above, the outer diameter of the end portion 37 of the bend pipe 36 is smaller than the outer diameter of the end portion 33 of the main pipe 32, so that the primary pipe is expanded for joining the main pipe 32 and the bend pipe 36. The rate of expanding the main pipe 32 end portion 33 into which the bend pipe 36 end portion 37 is inserted later can be made zero. That is, the end 37 of the bend pipe 36 can be inserted and joined while the end 33 of the main pipe 32 is primary expanded.

  In addition, since the main pipe 32 is subjected to the secondary pipe expansion after the primary pipe expansion and the thickness thereof is not further reduced, the strength of the welded portion with the end portion 33 and the bend pipe 36 and the vicinity of the welded portion are not reduced. Can be greatly improved as compared with the prior art. Thereby, for example, even when the gas cooler 24 is used in a refrigerant cycle in which a high pressure side such as carbon dioxide has an extremely high pressure, it is possible to avoid inconvenience that the main pipe 32 is damaged such as a crack. Further, since it is possible to simplify the processing work required for expanding the end portion 33 of the main pipe 32, the production cost of the gas cooler 24 (heat exchanger) can be reduced.

  Further, the outer diameter of the bend pipe 36 is formed smaller than the outer diameter of the end part 33 of the main pipe 32 before the primary pipe expansion, and the outer diameter of the end part 33 of the main pipe 32 after the primary pipe extension is set to bend. The outer diameter of the pipe 36 is weldable when the end 37 is inserted. Moreover, since the plate thickness with respect to the pressure strength of the pipe can be reduced with respect to the same pressure resistance by reducing the outer diameter of the pipe, the productivity of the bend pipe 36 itself is improved and the material cost is reduced with this thinning. It becomes possible to make it.

  Moreover, the outer diameter of the end part of the bend pipe 36 is made smaller than the inner diameter of the end part 33 of the main pipe 32 after the primary pipe expansion. Thereby, since the end part 37 of the bend pipe 36 can be inserted and welded without expanding the end part 33 of the main pipe 32, the strength can be further improved and the weldability can be improved. Become.

  Further, the end portion 37 of the bend pipe 36 is formed with a protrusion 39 that comes into contact with the end portion 33 of the main pipe 32 when inserted into the main pipe 32. The dimensions can be determined at the protrusion 39. In particular, when the outer diameter of the bend pipe 36 is smaller than the entire inner diameter of the main pipe 32, the insertion dimension of the end 37 of the bend pipe 36 can be determined by the protrusion 39. Productivity can be further improved.

  Next, FIG. 6 shows an enlarged view of a main part of a gas cooler 24 as a heat exchanger according to another embodiment of the present invention. The gas cooler 24 has substantially the same configuration as the above-described embodiment. Hereinafter, different parts will be described. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. That is, as shown in FIG. 6, the bend pipe 36 does not extend the tip of the end portion 37 to the tube plate 27, and is formed in a short length to a position separated from the tube plate 27 by a predetermined distance.

  As described above, since the end portion 37 of the bend pipe 36 is configured to be shorter than that of the first embodiment, workability for inserting the end portion 37 of the bend pipe 36 into the end portion 33 of the main pipe 32 can be improved. . In addition, since it is possible to simplify the processing operation of the end portion 37 of the bend pipe 36, the production cost of the gas cooler 24 (heat exchanger) can be reduced.

  Next, FIG. 7 shows an enlarged view of a main part of a gas cooler 24 as a heat exchanger according to another embodiment of the present invention. The gas cooler 24 has substantially the same configuration as the above-described embodiment. Hereinafter, different parts will be described. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. That is, the main pipe 32 is formed in a cylindrical shape having an outer diameter of 7.94 mm, a wall thickness of 1.00 mm, and an inner diameter of 5.94 mm (shown in the column of the present technology 1 in FIG. 12), and the other from one end. A straight line having substantially the same thickness is formed up to the end, and a substantially central portion is curved and formed in a U shape.

  The bend pipe 36 has an outer diameter of 6.35 mm and a wall thickness of 1.00 mm, and is formed in a cylindrical shape having substantially the same wall thickness from one end to the other end. The outer diameter of the bend pipe 36 is smaller than the outer diameter of the main pipe 32 and larger than the inner diameter. The bend pipe 36 is not formed with a protrusion 39 that abuts the end 33 (tip) of the main pipe 32 when the end 37 of the bend pipe 36 is inserted into the main pipe 32 described above. .

  Then, the main pipe 32 is fixed to the heat exchange fins 26... And the tube plate 27..., And the main pipe 32 is fixed. The secondary pipe is expanded like the primary pipe, and the large diameter portion 35 is formed at the end. In this way, the main pipe 32 that has been primarily expanded and has an inner diameter of 6.34 mm is secondarily expanded to provide the large-diameter portion 35 having an inner diameter of approximately 6.50 mm. A stepped portion 34 is formed at the boundary between the primary expanded portion and the secondary expanded portion. The outer diameter of the end portion of the bend pipe 36 is smaller than the inner diameter of the end portion 33 of the main pipe 32. Specifically, the gap between the inner diameter of the large-diameter portion 35 of the main pipe 32 and the periphery of the outer diameter of the bend pipe 36 is about 0.075 mm, so that brazing (welding material) welding of the main pipe 32 and the bend pipe 36 is performed. A suitable gap is formed.

  When the end portion 37 of the bend pipe 36 is inserted into the large diameter portion 35 from the end portion 33 of the main pipe 32 that has been subjected to secondary expansion, the secondary expansion portion and the primary expansion portion of the main pipe 32 end portion 33 The step portion 34 formed therebetween prevents the end portion 37 of the bend pipe 36 from being inserted further in the direction of the straight pipe portion 32A. In this state, the flare 32B of the main pipe 32 and the bend pipe 36 are welded as described above. In this way, the rate of expanding (secondary expansion) of the main pipe 32 end 33 is made smaller than the rate of expansion of the conventional main pipe end, and the outer diameter of the end of the bend pipe 36 is secondary expanded. Since it is formed smaller than the outer diameter of the rear end portion 33 of the main pipe 32, the thickness of the main pipe 32 does not become thinner than before.

  Thereby, the intensity | strength of the main pipe 32 end part 33 and the welding part with the bend pipe 36 and the welding part vicinity can be improved rather than before. Thereby, for example, even when the gas cooler 24 is used in a refrigerant cycle in which a high pressure side such as carbon dioxide has an extremely high pressure, it is possible to avoid inconvenience that the main pipe 32 is damaged such as a crack. Further, since it is possible to simplify the processing work required for expanding the end portion 33 of the main pipe 32, the production cost of the gas cooler 24 can be reduced.

  Further, it is not necessary to reduce the diameter of the end portion of the bend pipe 36, and the bend pipe 36 itself can be thinned by reducing the pipe diameter of the bend pipe 36 itself. Further, as the wall thickness is reduced, the productivity of the bend pipe 36 itself is improved, and the material cost can be reduced.

  Next, FIG. 8 shows an enlarged view of a main part of a gas cooler 24 as a heat exchanger according to another embodiment of the present invention. The gas cooler 24 has substantially the same configuration as that of the first embodiment. Hereinafter, different parts will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. That is, the bend pipe 36 has an outer diameter of 6.00 mm and a wall thickness of 1.00 mm, and is formed in a cylindrical shape having substantially the same wall thickness from one end to the other end.

  Then, a tube expansion jig (not shown) is inserted into the end portion of the bend pipe 36 and is expanded by being pushed from the inside, thereby performing primary tube expansion and forming a large diameter portion 40. The outer diameter of the large diameter portion 40 provided at the end of the bend pipe 36 is 6.20 mm. Specifically, the gap between the inner diameter of the end 33 of the main pipe 32 and the periphery of the outer diameter of the bend pipe 36 is about 0.07 mm, which is suitable for brazing (welding material) welding of the main pipe 32 and the bend pipe 36. Configured in the gap. In other words, the outer diameter of the large-diameter portion 40 that is primarily expanded at the end portion 37 of the bend pipe 36 is formed to be smaller than the inner diameter after the main piping 32 is primarily expanded. In the fourth embodiment, when the end 37 is inserted into the end 33 of the main pipe 32 at the end 37 of the bend pipe 36, the protrusion abuts against the end 33 (tip end) of the main pipe 32. Although the portion 39 is not provided, the protrusion 39 as described above may be provided at a predetermined position of the large-diameter portion 40 provided in the bend pipe 36.

  Thus, since the main pipe 32 does not perform the secondary pipe expansion as in the prior art, it does not become thinner than the wall thickness after the primary pipe expansion. Thereby, the intensity | strength of the welding part with the main piping 32 edge part 33 and the bend piping 36 or a welding part vicinity can be improved significantly conventionally. Therefore, for example, even when the gas cooler 24 is used in a refrigerant cycle in which the high pressure side has a very high pressure such as carbon dioxide, it is possible to avoid the inconvenience that the main pipe 32 is damaged such as a crack. Further, since secondary pipe expansion is not performed, it is possible to simplify the processing work required for pipe expansion of the main pipe 32 end 33, and to reduce the production cost of the gas cooler 24 (heat exchanger). become.

  Next, FIG. 9 shows an enlarged view of a main part of a gas cooler 24 as a heat exchanger according to another embodiment of the present invention. The gas cooler 24 has substantially the same configuration as that of the first embodiment. Hereinafter, different parts will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. That is, the bend pipe 36 has an outer diameter of 6.00 mm and a wall thickness of 1.00 mm, and is formed in a cylindrical shape having substantially the same wall thickness from one end to the other end. The outer diameter of the bend pipe 36 is smaller than the inner diameter after the main pipe 32 is primarily expanded.

  Further, the end portion 37 of the bend pipe 36 is provided with a flare portion 36B similar to the flare portion 32B, which is flare processed by a flare processing jig (not shown). Then, an end portion 37 of the bend pipe 36 to which an annular brazing material (not shown) is attached in advance is inserted from the end portion 33 of the main pipe 32 with a predetermined size, and the inside of the end portion 33 of the main pipe 32 and around the bend pipe 36 is A brazing material is provided between them. As a result, a certain gap is formed between the periphery of the bend pipe 36 and the end 33 of the main pipe 32.

  The bend pipe 36 and the main pipe 32 are welded to form the meandering refrigerant pipe 4 in which the bend pipe 36 and the main pipe 32 are connected and fixed. In this case, the gap between the end portion 33 of the main pipe 32 and the end portion of the bend pipe 36 can be filled with brazing material to form a certain gap, so that the periphery of the bend pipe 36 can be completely sealed. It becomes. As a result, it is possible to ensure the joining and sealing properties between the main pipe 32 and the bend pipe 36, and to prevent the refrigerant gas from leaking.

  Next, FIG. 10 shows an enlarged view of a main part of a gas cooler 24 as a heat exchanger according to another embodiment of the present invention. The gas cooler 24 has substantially the same configuration as that of the first embodiment. Hereinafter, different parts will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. That is, the outer diameter of the end 37 of the bend pipe 36 is smaller than the inner diameter of the end 33 of the main pipe 32. Specifically, regardless of the outer diameter of the bend pipe 36 and the outer diameter of the main pipe 32, the outer diameter of the bend pipe 36 end 37 is smaller than the inner diameter of the main pipe 32 end 33.

  Then, a predetermined range of the end portion 37 of the bend pipe 36 is contracted by a diameter reducing jig (not shown), and the primary diameter reduction is performed. Thereby, the small diameter part 42 by which the outer diameter of the end part 37 of the bend piping 36 was reduced to 6.20 mm is provided. A gap between the outer diameter of the small diameter portion 42 and the inner diameter of the end portion 33 of the main pipe 32 is configured as a gap suitable for welding (about 0.07 mm). The bend pipe 36 is provided with a stepped portion 36C at the boundary between the primary diameter reduced small diameter portion 42 and the primary diameter reduced portion.

  Then, when the end portion 37 of the bend pipe 36 whose primary diameter is reduced is inserted from the end portion 33 of the main pipe 32, the stepped portion 36 </ b> C of the bend pipe 36 comes into contact with the end portion 33 (tip portion) of the main pipe 32. Further, the bend pipe 36 is prevented from being inserted further. In this state, the flared portion 32B of the main pipe 32 and the bend pipe 36 are welded as described above. As described above, since the end 33 of the main pipe 32 is not secondary expanded, the thickness of the main pipe 32 is not reduced as in the prior art. Thereby, the intensity | strength of the welding part with the main piping 32 end part 33 and the bend piping 36 can be improved significantly conventionally.

  Further, for example, even when the gas cooler 24 is used in a refrigerant cycle in which the high pressure side has a very high pressure such as carbon dioxide, it is possible to avoid inconvenience that the main pipe 32 is damaged such as a crack. Further, since it is possible to simplify the processing work required for expanding the end portion 33 of the main pipe 32, the production cost of the gas cooler 24 (heat exchanger) can be reduced.

  Next, FIG. 11 shows an enlarged view of a main part of a gas cooler 24 as a heat exchanger according to another embodiment of the present invention. The gas cooler 24 has substantially the same configuration as that of the first embodiment. Hereinafter, different parts will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. That is, the outer diameter, thickness, and inner diameter of the bend pipe 36 are configured in the same manner as the main pipe 32.

  An end portion 37 of the bend pipe 36 is provided with a constricted portion 38 that is constricted inward (center direction) by an unillustrated constricting jig. The narrowed portion 38 of the bend pipe 36 squeezed inward is a flare portion of the main pipe 32 with the end 37 of the bend pipe 36 and the straight pipe portion 32A of the main pipe 32 positioned on the extension line. Abutted and joined to 32B. When the end surface of the end portion 33 of the bend pipe 36 is brought into contact with the flare portion 32B of the main pipe 32, the throttle portion 38 is formed at an angle that makes surface contact with the flare portion 32B of the main pipe 32.

  Thereby, the intensity | strength of the welding part with the main piping 32 edge part 33 and the bend piping 36 can be improved conventionally. Therefore, for example, even when the gas cooler 24 is used in a refrigerant cycle such as carbon dioxide in which the high pressure side has an extremely high pressure, it is possible to avoid inconvenience that the main pipe 32 is damaged such as a crack. . In addition, since the processing of the end portion 33 of the main pipe 32 only needs to be flared, the production cost can be reduced.

  On the other hand, in the above-described embodiment, as shown in the present technology 2 in FIG. 12, the primary pipe expansion provided in the main pipe 32 having an outer diameter of 7.94 mm, a wall thickness of 1.00 mm, and an inner diameter of 5.94 mm. When the rear inner diameter is 6.34 mm and the inner diameter after secondary pipe expansion is 6.34 mm, the outer diameter of the bend pipe 36 is 6.20 mm and the wall thickness is 1.00 mm. Further, as shown in the present technology 1, the inner diameter after primary expansion provided in the main pipe 32 configured to have an outer diameter of 7.94 mm, a wall thickness of 1.00 mm, and an inner diameter of 5.94 mm is 6.34 mm. When the inner diameter after expansion is 6.50 mm, the outer diameter of the bend pipe 36 is 6.35 mm and the wall thickness is 1.00 mm. In this way, when the gas cooler 24 is used in a refrigerant cycle in which the high pressure side such as carbon dioxide is at a very high pressure, the disadvantage that the main pipe 32 is damaged such as a crack is avoided in advance. Will be able to.

  Further, since the gas cooler 24 of the present invention has improved the strength of the welded portion with the end portion 33 of the main pipe 32 and the bend pipe 36 as compared with the prior art, for example, as shown in the present technology 3 in FIG. 36 has an outer diameter of 6.35 mm and a wall thickness of 1.00 mm, and the main pipe 32 has an outer diameter of 7.94 mm, a wall thickness of 0.92 mm, and an inner diameter of 6.10 mm. Even when the inner diameter after primary expansion is 6.50 mm and the inner diameter after secondary expansion is 6.50 mm, it can be used for a refrigerant cycle in which the high pressure side such as carbon dioxide has an extremely high pressure. Become.

  As a result, the expansion ratio of the main pipe 32 due to the primary expansion and the secondary expansion can be further reduced, and the strength of the welded portion between the end 33 of the main pipe 32 and the bend pipe 36 can be further improved as compared with the prior art. Will be able to. Therefore, even when the gas cooler 24 is used in a refrigerant cycle such as carbon dioxide in which the high pressure side has an extremely high pressure, it is possible to avoid inconveniences such as cracks in the main pipe 32. Further, since the thickness of the main pipe 32 can be reduced, it is possible to simplify the processing work required for expanding the end portion 33 of the main pipe 32, and to reduce the production cost.

  In addition, although the shape, dimension, etc. of the heat exchanger (gas cooler 24) were described in the Example, it cannot be overemphasized that a heat exchanger may change a shape, a dimension within the range which does not deviate from the summary. Of course, the present invention is not limited to the above-described embodiments, and various other modifications can be made without departing from the spirit of the present invention.

It is a refrigerant circuit figure of the Example provided with the heat exchanger of this invention (Example 1). It is a perspective view at the time of seeing the heat exchanger of the present invention from one side. It is a perspective view at the time of seeing the heat exchanger of the same FIG. 2 from the other side. It is a figure which shows the principal part of the gas cooler as a heat exchanger of the Example of this invention. It is a principal part enlarged view of the gas cooler as a heat exchanger of the Example of this invention. It is a principal part enlarged view of the gas cooler as a heat exchanger of the Example of this invention (Example 2). It is a principal part enlarged view of the gas cooler as a heat exchanger of the Example of this invention (Example 3). It is a principal part enlarged view of the gas cooler as a heat exchanger of the Example of this invention (Example 4). It is a principal part enlarged view of the gas cooler as a heat exchanger of the Example of this invention (Example 5). It is a principal part enlarged view of the gas cooler as a heat exchanger of the Example of this invention (Example 6). It is a principal part enlarged view of the gas cooler as a heat exchanger of the Example of this invention (Example 7). It is a figure which shows the comparative dimension of the main piping and bend piping of a gas cooler as a heat exchanger of the Example of this invention, and the main piping and bend piping of a prior art example. It is a principal part enlarged view of the conventional heat exchanger (gas cooler).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary compressor 4 Electric element 14 Rotation compression mechanism part 18 Refrigerant introduction pipe 20 Refrigerant introduction pipe 22 Refrigerant discharge pipe 24 Gas cooler 26 Heat exchange fin 27 Tube plate 30 Refrigerant piping 32 Main piping 33 End part 36 Bend piping

Claims (7)

In a heat exchanger in which a meandering refrigerant pipe is constituted by a main pipe having a straight pipe portion and a curved bend pipe that interconnects ends of the main pipe.
The end of the bend pipe is inserted into the end of the main pipe and welded, and the outer diameter of the bend pipe end is smaller than the outer diameter of the main pipe end. Exchanger.   2. The heat exchanger according to claim 1, wherein an outer diameter of the bend pipe is smaller than an outer diameter of the main pipe end portion as a whole.   The heat exchanger according to claim 1 or 2, wherein an outer diameter of the bend pipe end is smaller than an inner diameter of the main pipe end.   The heat exchanger according to claim 3, wherein the outer diameter of the bend pipe is smaller than the inner diameter of the end portion of the main pipe over the whole.   The heat exchanger according to claim 3 or 4, wherein the bend pipe is formed with a protrusion that comes into contact with an end of the main pipe when the bend pipe is inserted into the main pipe.   6. The pipe plate according to claim 1, further comprising a tube plate for holding an end portion of the main pipe, wherein the bend pipe is inserted to a contact position between the main pipe and the tube plate. The heat exchanger according to crab. In a heat exchanger comprising a meandering refrigerant pipe from a main pipe having a straight pipe portion and a curved bend pipe interconnecting ends of the main pipe,
The end of the bend pipe is squeezed inward, the end of the main pipe is flared, and the end of the bend pipe is welded in contact with the end of the main pipe. A heat exchanger characterized by having

Images