JP2004270928A - Double pipe joint structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double pipe joint structure capable of connecting double pipes formed with an internal pipe and an external pipe integrally or separately, respectively, with improved workability and reduced cost. <P>SOLUTION: A joint member 21 is constituted by joining one end with the external pipe 2 of the first double pipe 1 by mouth drawing and fitting the external pipe 2 internally. In this joint member 21, the external pipe 12 of the second double pipe 11 is internally fitted, and a cylindrical locking member 25 is mounted at the outer periphery. The locking member 25 is constituted in such a way that an elastic locking part 26 is provided at one end and an insertion channel part 21c formed in the vicinity of an end part on one side of the joint member 21 is inserted to lock it in a locking channel part 12c formed in the external pipe 12 of the second double pipe 11. In the internal pipe 3 of the first double pipe 1, a female side joint part 3b is formed in an end part, and a tip part of the internal pipe 13 of the second double pipe 11 is internally fitted. A diameter of an elastic locking part 26 of the locking member 25 is expanded by advance of the external pipe 12 to advance into the joint member 21 of the external pipe 12. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a double pipe joint structure for connecting a double pipe having an inner pipe and an outer pipe, and more particularly, to a double pipe joint structure for connecting a double pipe in which an inner pipe and an outer pipe are formed integrally or separately. The present invention relates to a heavy pipe joint structure.

  Generally, in an air conditioner (hereinafter, referred to as an air conditioner) constituting a refrigeration cycle, a pipe-shaped piping member is connected between a compressor, a condenser, an expansion valve, and an evaporator to circulate a refrigerant. Since the cost of this piping member increases as its length increases, in the case of an air conditioner, it has been studied to shorten the arrangement position of each device as much as possible. However, in particular, in the case where the air conditioner is mounted on a vehicle, for example, in a one-box type vehicle, the evaporator for the rear seat is arranged with the piping member extended to the rear side, so that the piping length is It had become extremely long.

  For this reason, it has been customary to construct a double tube to save its length. As an example of forming a double pipe, there is one in which an inner pipe and an outer pipe are connected by a connecting rib and integrally formed by extrusion molding or drawing. A double pipe joint structure for connecting the double pipes is disclosed in Patent Document 1.

  According to this, as shown in FIG. 17, the inner pipe 72 and the outer pipe 73 are connected by connecting ribs in which the outer peripheral surface of the inner pipe 72 and the inner peripheral surface of the outer pipe 73 are arranged radially. Then, at the end, the distal end of the outer pipe 73 is cut out so that the inner pipe 72 protrudes from the outer pipe 73, and the inner pipe 72 is joined to the joint member 80 and the distal end of the outer pipe 73 is closed. A pipe-shaped connecting member 75 surrounding the protruding inner pipe 72 is joined between the protruding portion 72 a of the inner pipe 72 and the outer pipe 73. Then, in order to connect the passage of the fluid flowing in the outer pipe 73 to the joint member 80, the connecting member 75 is connected to the joint member 80 via the extension pipe member 76.

  The distal end of the inner pipe 72 and the distal end of the extension piping member 76 are connected to a first joint member 80, and two male portions 81 and 82 formed on the first joint member 80 are provided separately from each other. After being joined to the female part of the second joint member 85 connected from the piping member of the above, it is configured to be connected by a bolt 86 or the like.

The double pipe 71 is applied to a one-box type automotive air conditioner, and is provided in a passage leading from the vehicle exterior air conditioner to the rear seat air conditioning unit.
JP 2001-235081 A (pages 3 to 7, FIGS. 1 to 3)

  However, since the adoption of the double pipe originally shortens the length of the pipe and measures cost reduction, it is not desirable that the structure to be connected to the joint member is complicated and the cost is increased. For example, in the configuration shown in the conventional patent document 1, in order to protrude the inner tube 72, the tip of the outer tube 73 must be cut off, which increases the processing cost and the outer tube passage. In order to pipe the extension piping member 76 to the joint member 80 as described above, the cost for arranging the connecting member 75 has increased, and conversely, the cost has increased.

  Further, the male members 81 and 82 of the first joint member 80 connecting the inner pipe 72 and the outer pipe 73 of one double pipe 71 are separately piped. After being joined to the female part of the second joint member 85 that connects the two pipe members, the joint is connected with the bolt 86 or the like, so that the double pipe 71 and the joint member 80 can be instantaneously connected. Instead, the connection time was troublesome. Further, the first joint member 80 and the second joint member 85 are respectively joined to the branched inner fitting 72 and the outer pipe 73 (extension piping member 76) by brazing or welding, so that they are respectively joined. In addition to increasing the size of the joint member, a considerable amount of time was spent in joining the inner and outer tubes.

The present invention has been made to solve the above-described problems, and has a structure in which an inner pipe and an outer pipe are formed integrally or separately from each other and connected to each other, or a double pipe and two parallel pipes. It is an object of the present invention to provide a double pipe joint structure that can be easily connected to a piping member and configured at low cost to reduce costs.
According to the first aspect of the present invention, the inner pipe and the outer pipe are formed integrally or separately and connected by the connecting means, and the first double pipe and the second double pipe are connected by the joint means. ing.

  When one of the first double pipe and the second double pipe enters the other double pipe, the diameter of the joint means is expanded by elastic deformation, and the one double pipe is expanded. Further, the joint means is reduced in diameter to connect the first double pipe and the second double pipe, so that the connection can be made with one touch, and the workability can be greatly improved, The cost can be reduced without connecting the two double tubes by brazing or welding.

  According to a second aspect of the present invention, the joint means according to the first aspect of the present invention includes a joint member having one end joined to one of the double pipes by a plastic deformation means, and an elastic locking portion, which is capable of expanding and reducing the diameter. For example, when the second double pipe is moved toward the first double pipe, the outer pipe of the second double pipe is engaged since the second double pipe is moved toward the first double pipe. When the outer tube of the second double tube reaches a predetermined position while pressing the elastic locking portion of the stop member to expand the diameter and pressurize the diameter, the elastic locking portion of the locking member is reduced in diameter. To the outer tube of the second double tube.

  At this time, the inner pipe of the second double pipe enters the joint member together with the entry of the outer pipe of the second double pipe, and is fitted and connected to the inner pipe of the first double pipe. .

  Therefore, the first double pipe and the second double pipe are connected to each other by one-touch without being connected to the joint member by brazing, welding, or the like. Thus, the workability can be improved and the cost can be reduced.

  According to the third aspect of the present invention, by forming the insertion groove for inserting the elastic locking portion into the joint member according to the second aspect of the present invention, the elastic locking portion of the locking member can be inserted. The locking member can be mounted by restricting the movement of the stop member to the joint member along the axial direction, and the elastic locking portion that penetrates the insertion groove portion can be instantaneously locked to the second double pipe by elasticity. Can be improved. Further, since the locking member can be formed in a cylindrical shape covering the joint member with one member, the double pipe joint structure can be provided which can be formed at a low cost and which is compact.

  Also, as in the invention according to the fourth aspect, the one end of the joint member according to the second aspect is simply joined to the groove formed in the outer pipe of the first double pipe by mouth drawing to form the second joint. Since the outer pipe of the heavy pipe can be inserted, the joint member can be easily mounted and can be made extremely compact. Further, the outer tube of the second double tube can be easily inserted.

  According to the fifth aspect of the present invention, since the locking member has the horizontal window portions extending alternately from both end surfaces in the axial direction, the thick portion where the horizontal window portion is not formed has one end. The elastic locking portion, which is pressed by the outer tube of the second double tube, can be easily expanded by disposing the elastic locking portion at the distal end thereof. The outer diameter of the second double pipe can be advanced into the joint member. Therefore, the first double pipe and the second double pipe can be joined with one touch, and the workability can be greatly improved.

  Furthermore, in the invention according to claim 6, by forming a groove in the outer tube of the second double tube along the circumferential direction, the second double tube enters the inside of the joint member and is located at a predetermined position. When it reaches, since the elastic locking portion of the locking member can be locked in the groove, the outer pipe of the second double pipe locked by the locking member is reliably restricted from moving in the axial direction. It can be connected to the first double pipe.

  In the invention according to claim 7, the locking member according to claim 6 shows another mode of locking with, for example, the outer pipe of the second double pipe. By attaching the ring member to the groove formed in the outer tube, the elastic locking portion of the locking member inserted through the insertion groove portion of the joint member allows the outer tube of the second double tube to enter the joint member. Is locked via a ring member. At this time, if the ring member and the joint member are formed so as to be pressed against each other, the airtightness can be improved by locking the elastic locking portion to the ring member.

  Further, in the invention according to claim 8, the locking member according to claim 6 shows still another mode of locking with, for example, the outer pipe of the second double pipe, and the invention according to claim 7 Instead of the ring member, the outer pipe of the second double pipe is provided integrally with a bulged portion having a larger diameter than the general cylindrical portion. As a result, similarly to the invention of claim 7, the elastic locking portion of the locking member inserted through the insertion groove portion of the joint member is provided on the bulging portion of the outer tube of the second double pipe which has entered the joint member. Lock. At this time, if the bulged portion of the outer tube and the joint member of the second double tube are formed so as to be pressed against each other, the airtightness is improved by locking the elastic locking portion to the bulged portion. be able to. In addition, since a separate member such as a ring member is not newly manufactured, a double pipe joint structure can be provided at a lower cost.

  According to the ninth aspect of the present invention, for example, the distal end of the outer tube in the first double tube is formed so as to expand from the general cylindrical portion to form a female joint, and the female joint has a second double tube. By attaching a lockable member to the outer tube of the pipe, a joint means is constituted by the female joint and the lock member, and the outer tube of the second double pipe enters the female joint. If the outer tube of the second double tube is locked by the locking member, the second double tube can be connected to the first double tube. In addition, when the outer tube of the second double tube enters the female joint portion, it presses the elastic locking portion of the locking member so that the diameter of the second double tube can be expanded. It is possible to improve workability and reduce costs.

  According to the tenth aspect of the present invention, even in a double pipe joint structure for connecting a double pipe and a two-way branch joint to which two pipes arranged side by side can be connected, the double pipe is connected to the two-way branch joint. By attaching a locking member for locking the outer pipe, a joint means can be formed, and the double pipe and the two-way branch joint can be connected. By connecting the high-pressure pipe communicating with the inner pipe of the double pipe and the low-pressure pipe communicating with the outer pipe of the double pipe to the two-way branch joint, the double pipe can be branched and piped separately. It becomes.

  That is, since the locking member is provided with the elastic locking portion that is inserted into the groove formed in the two-way branch joint and locked to the outer tube of the double pipe, the elastic locking portion is provided with the two-way branch. When the outer pipe of the double pipe is pressed by the outer pipe of the double pipe that has entered the hollow portion of the branch joint, the outer pipe of the double pipe further enters, and when reaching the predetermined position, the elastic locking portion Is reduced in diameter and locked to the outer tube of the double tube. Therefore, also in the double pipe joint structure according to the present invention, the two-way branch joint and the double pipe can be connected with one touch, and it is possible to significantly improve workability and reduce costs.

  According to the eleventh aspect of the present invention, the first double pipe and the second double pipe which are formed integrally or separately from the inner pipe and the outer pipe and are connected by the connecting means are joined by the joint means. ing.

  When the first double pipe and the second double pipe are at the connection position, the joint means is joined to one of the double pipes by the plastic deformation means, and the first double pipe and the second double pipe are connected to each other. The first double pipe and the second double pipe are fastened by connecting the double pipe or by fastening means. Accordingly, the workability can be greatly improved and the cost can be reduced without connecting the two double tubes by brazing or welding.

  According to the twelfth aspect of the present invention, the first double pipe and the second double pipe which are formed integrally or separately from the inner pipe and the outer pipe and connected by the connecting means are connected by the joint means. ing.

  When the first double pipe and the second double pipe are in the connection position, the joint means presses one of the double pipes in a direction in which the two double pipes face each other by screw means. The first double tube and the second double tube are connected. Therefore, the two pipes are not connected by brazing or welding, so that workability can be improved and cost can be reduced.

  According to the thirteenth aspect of the present invention, the double pipe in which the inner pipe and the outer pipe are integrally formed is provided with the fin portion that connects the inner pipe and the outer pipe in the radial direction. When connecting the pipe to the joint means or when expanding the distal end of the inner pipe, the pipe is hardly crushed and becomes stable, so that an easy operation can be performed.

  According to the fourteenth aspect, when inserting the male part of the inner tube of the second double pipe into the female part of the inner pipe of the first double pipe, the female part of the inner pipe can be easily inserted by expanding its diameter. At the same time, when performing the diameter expansion processing, the processing for increasing the surface roughness of the inner peripheral surface of the enlarged diameter portion can be performed at the same time, and the airtightness can be improved when the seal member is interposed.

  In the invention according to claim 15, the fin portion of claim 13 is formed in a spiral shape, so that the rigidity of the fin portion is reduced to reduce the tension on the inner tube and the outer tube, and the inner tube is subjected to a diameter expansion process and an outer process. It is possible to easily perform plastic deformation processing such as contraction of a pipe.

  According to the sixteenth aspect, since one end of the fin part of the thirteenth aspect is formed so as to be directed to a position eccentric from the center point of the inner tube, the rigidity of the fin part is reduced similarly to the invention of the fifteenth aspect. It is possible to reduce the tension on the inner pipe and the outer pipe by lowering the pipe, and to facilitate the plastic deformation processing of the inner pipe in diameter expansion processing and the outer pipe contraction.

  In the invention according to claim 17, the fin portion according to claim 13 is formed to be bent between the inner tube and the outer tube. It is possible to reduce the tension on the outer pipe and facilitate the plastic deformation processing of the inner pipe such as the diameter expansion processing and the outer pipe contraction.

  According to the eighteenth aspect, the fin portion is formed to be thinner than the thickness of the inner tube and the inner tube is formed to be thinner than the thickness of the outer tube. Can be easily plastically deformed.

  According to the nineteenth aspect of the invention, when the two double pipes are connected via the joint means, the opposed distal ends of the inner pipes in the respective double pipes are opened to form a large diameter. In addition, since the two end portions are connected by the bypass inner pipe, the inner pipe and the outer pipe are formed by integral molding. This eliminates the need to cut out the distal end portion of the outer tube for projecting the tube from the outer tube, thereby reducing costs.

  According to the twentieth aspect of the present invention, even when the double pipe is piped to the two-way branch joint, the introduction port communicating with the inner pipe in the two-way branch joint and the inner pipe of the double pipe are connected by the bypass inner pipe. This eliminates the need to cut out the distal end portion of the outer tube for projecting the inner tube from the outer tube, as in the case of claim 19, thereby reducing costs.

  According to the twenty-first aspect, when the inner pipes connect the two double pipes connected to the bypass inner pipe, one of the first double pipe and the second double pipe is connected. When the heavy pipe enters the other double pipe, the joint means expands by elastically deforming, and when one of the double pipes further enters, the joint means contracts and the first double pipe and the first double pipe are reduced in diameter. Since two double pipes are connected, they can be connected with one touch, greatly improving workability, and reducing the cost without connecting the two double pipes by brazing or welding. You can also plan.

  In the invention according to claim 22, when connecting the two double pipes, since the joint means includes the first screw means having a female thread and the second screw means having a male thread, After the inner pipes are connected to each other by the bypass inner pipe and the two double pipes are arranged to face each other, the first screw means and the second screw means are screwed together to form two double pipes. Since the pipes are connected, workability can be greatly improved and costs can be reduced as compared with the case where the double pipes are connected by brazing or welding. Furthermore, the interposition of the bypass inner pipe eliminates the need to cut out the distal end of the outer pipe, so that the cost can be reduced.

  According to the invention of claims 23 to 26, the first screw means of claim 22 may be, for example, a C ring mounted on the outer tube of the first double pipe, a cylindrical member mounted by spinning, or The first double pipe and the second double pipe can be connected at a predetermined position by restricting the position in the axial direction by the restricting means with the cylindrical member mounted by the drawing process.

  In the invention according to claim 27, since the second screw means forms a hexagonal union part, the union part is rotated with a frequently used hexagonal wrench after facing the two double tubes. It is possible to connect two double pipes by an easy operation.

  According to the twenty-eighth or twenty-ninth aspect of the present invention, the bypass inner pipe according to the nineteenth or twentieth aspect has an O-ring attached to both ends of a cylindrical pipe member, or rubber at both ends of a resin pipe member. Since the members are arranged and formed by two-color molding, it is possible to connect the double pipes or the double pipe and the two-way branch joint with the bypass inner pipe which maintains the airtightness and reduces the cost. .

  In the invention according to claim 30, by holding the bypass inner pipe with the holding ring, the connected bypass inner pipe can be stably assembled.

  Hereinafter, in the present invention, an embodiment of a joint structure in which an inner pipe and an outer pipe are branched and connected to two double pipes having an inner pipe and an outer pipe or one double pipe will be described with reference to the drawings. Is what you do.

  As shown in FIGS. 1 to 3, the double pipe joint structure according to the first embodiment includes an outer pipe 2 that circulates a low-pressure refrigerant and an inner pipe 3 that circulates a high-pressure refrigerant and inserted into the outer pipe 2. A second double pipe composed of an outer pipe 12 circulating the low-pressure refrigerant and an inner pipe 13 inserted into the outer pipe 12 by circulating the high-pressure refrigerant. A joint member 21 having one end joined to the heavy pipe 11, the outer pipe 2 of the first double pipe 1 formed in a cylindrical shape, and internally fitting the outer pipe 12 of the second double pipe 11; A locking member 25 formed in a cylindrical shape so as to cover around the joint member 21 while being arranged to be locked in an insertion groove portion 21c described later formed in a long hole shape in the circumferential direction on the other end side of the fitting member 21. , Is configured.

  In the first double pipe 1, an inner pipe 3 formed separately from the outer pipe 2 is inserted into the outer pipe 2, and an annular portion 28a and a circle are formed therein as shown in FIG. A fin portion 28b extending helically outward at equal intervals from the outer peripheral surface of the ring portion 28a; and a support member 28 inserted and arranged between the inner tube 3 and the outer tube 2 to form the outer tube 2. And the inner pipe 3 are connected.

  Note that, even if the fins projecting from the annular portion 28a are not formed in a spiral shape, the support member 28 may have a plurality of fins in a direction orthogonal to the annular portion 28, as shown in FIG. A supporting member 28A having a fin portion 28c formed at a location may be used, and as shown in FIG. 4C, a fin portion 28d formed at a plurality of locations inclining linearly from the annular portion 28a. The support member 28B may be used.

  Further, in the vicinity of both ends of the outer tube 2, a sealing groove 2b and a locking groove 2c each having a diameter smaller than the outer diameter of the general cylindrical part 2a are formed in the circumferential direction to be smaller than the general cylindrical part in order from the terminal side. I have. An O-ring 5 is mounted in the seal groove 2b, and one end of a joint member 21 is joined to the locking groove 2c near one end face of the both ends of the outer tube 2 by mouth drawing, and the other end face (not shown) An elastic locking portion 26 of a locking member 25 described later is locked in the nearby locking groove.

  One end of the inner pipe 3 of the first double pipe 1 is formed as a female joint 3b extending from the general cylindrical part 3a, and the other end is formed as a male joint. The female joint 3b of the inner pipe 3 of the first double pipe 1 and the male joint 13b of the second double pipe 11 are respectively formed so as to be fittable. The other male joint (not shown) (the same shape as the male joint 13b shown in the inner tube 13 of the second double pipe 11 described later) is formed with a seal groove having a smaller diameter than the general cylindrical portion 13a to form an O. Wearing a ring.

  On the other hand, in the second double pipe 11, the inner pipe 13 formed separately from the outer pipe 12 is inserted into the outer pipe 12, and the annular section 28a and the annular section 28a are formed therein as shown in FIG. A fin portion 28b helically extending outward at regular intervals from the outer peripheral surface of the portion 28a. And the inner tube 13 are connected.

  Further, near both ends of the outer tube 12, a sealing groove 12b and a locking groove 12c each having a diameter smaller than the outer diameter of the general cylindrical portion 12a are formed in the circumferential direction from the end face side. An O-ring 15 is mounted in the seal groove 12b, and one end of a joint member (not shown) (similar in shape to the joint member 31 joined to the first double pipe 1) is inserted into a lock groove near one end face. The elastic locking portion 26 of the locking member 25 is locked in the locking groove 12c near the other end face by drawing.

  Both ends of the inner tube 13 of the second double tube 11 have one end formed as a female joint (not shown) and the other end formed as a male joint 13b extending from the general cylindrical portion 13a. The female joint part 3b of the first double pipe 1 and the male joint part 13b of the second double pipe 11 are formed so as to be fitted respectively. The male joint portion 13b has a seal groove 13c having a smaller diameter than the general cylindrical portion 13a, and the O-ring 16 is mounted thereon.

  One end of the joint member 21 formed in a cylindrical shape is fitted with the outer tube 2 of the first double tube 1, and then the outer tube is formed by mouth drawing toward a locking groove 2 c formed in the outer tube 2. 2 is formed, and the other end is provided with an edge 21b having a diameter larger than the outer diameter of the general portion, and is formed along the circumferential direction in the shape of a long hole adjacent to the edge 21b. Are formed at a plurality of locations.

  The locking member 25 is formed in a tubular shape, and extends along one axial direction from a first horizontal window portion 25a extending from one end surface at equal intervals and a second horizontal window portion 25a extending from the other end surface. And two horizontal windows 25b. The first horizontal windows 25a and the second horizontal windows 25b are alternately arranged in the circumferential direction. The elastic locking portion 26 is arranged so as to protrude inward from one of the thick portions where the first horizontal window portion 25a or the second horizontal window portion 25b is not formed.

  Next, the operation of the double pipe joint structure in this embodiment will be described with reference to FIG.

  The first double pipe 1 is fitted with a joint member 21 having one end joined to a locking groove 2c formed in the vicinity of the end of the outer pipe 2 by mouth drawing. A locking member 25 in which the elastic locking portion 26 is inserted is mounted on 21c. On the other hand, one end of the second double pipe 11 is arranged at a position facing the opening of the joint member 21 with the male joint part 13b of the inner pipe 13 protruding from the tip of the outer pipe 12. .

  When the second double pipe 11 is moved toward the first double pipe 1, as the male joint part 13 b of the inner pipe 13 enters the opening of the joint member 21, the distal end of the outer pipe 12 joins The member 21 moves toward the inside of the edge 21 b and comes into contact with the elastic locking portion 26 of the locking member 25. Then, the elastic locking portion 26 is pressed by the distal end portion of the outer tube 12 of the second double tube 11 and expands in the insertion groove 21 c of the joint member 21. At this time, if the contact surface of the elastic locking portion 26 with the outer tube 12 is formed as an inclined surface, the diameter of the elastic locking portion 26 can be easily expanded when the outer tube 12 enters.

  When the second double pipe 11 further enters the joint member 21, the male joint 13 b of the inner pipe 13 in the second double pipe 11 is connected to the female joint of the inner pipe 3 of the first double pipe 1. The inner pipe 3 of the first double pipe 1 and the inner pipe 13 of the second double pipe 11 start connection into the portion 3b. On the other hand, when the outer tube 12 of the second double tube 11 enters the joint member 21 beyond the elastic locking portion 26, it fits on the inner peripheral surface of the joint member 21.

  The elastic locking portion 26 expanded by the outer tube 12 of the second double tube 11 causes the distal end of the outer tube 12 in the second double tube 11 to move to the first second tube by the movement of the outer tube 12. When the heavy tube 1 is moved to a position where it comes into contact with the tip of the outer tube 2, the locking groove 12c of the outer tube 12 reaches the position of the elastic locking portion 26, and the locking groove 12c is formed to have a small diameter. From this, the diameter is reduced by the elastic force and the engaging groove 12c is engaged. As a result, the outer tube 2 of the first double tube 1 and the outer tube 12 of the second double tube 11 are connected, and the first double tube 1 and the second double tube 11 are connected. The state shown in FIG. 2 is obtained.

  At this time, the outer tube 2 and the joint member 21 in the first double tube 1 are sealed with the O-ring 5, and the outer tube 12 and the joint member 21 in the second double tube 11 are sealed with the O-ring 15. Therefore, the low-pressure refrigerant passing through the outer tube 2 of the first double tube 1 passes through the outer tube 12 of the second double tube 11 in a state of improved airtightness without leaking to the outside. It will be. Further, since the inner pipe 3 of the first double pipe 1 and the inner pipe 13 of the second double pipe 11 are sealed by the O-ring 16, the inner pipe 3 of the first double pipe 1 is sealed. The high-pressure refrigerant passing inside passes through the inner pipe 13 of the second double pipe 11 in a state where the airtightness is improved without leaking to the outside.

  Therefore, according to the double pipe structure of the embodiment, since the second double pipe 11 can be connected to the first double pipe 1 with one touch, workability can be greatly improved and cost can be further reduced. Can be. Moreover, the joint structure for connecting the pair of double pipes 1 and 11 includes a cylindrical joint member 21 that covers the outer pipe 2 of the first double pipe 1, an insertion groove portion that covers the joint member 21 and Since it is composed of the cylindrical locking member 25 locked to 21c, it can be configured at low cost and compact.

  In this embodiment, as shown in FIG. 6, the end portion 23c of the joint member 23 may be connected to the joint member 23 after being raised by a tapered portion 23b having a tapered shape. That is, the joint member 23 is formed so that one end thereof rises from the joint portion 23a joined to the locking groove 2c of the outer tube 2 in the first double tube 1 by mouth drawing and the outer diameter of the general portion. It is formed to have a tapered portion 23b and an expanded edge portion 23c connected at the upper end of the tapered portion 23b. And, at a connecting portion between the tapered portion 23b and the edge portion 23c, insertion grooves 23d through which the elastic locking portions 26 of the locking members 25 are inserted are formed at a plurality of locations along the circumferential direction. The inner wall surface of the tapered portion 23b is formed as a tapered inner surface 23e.

  On the other hand, a ring member 18 made of a resin material or a metal material is attached to the locking groove 12c of the outer tube 12 of the second double tube 11 by outsert molding. The ring member 18 is formed to have a tapered outer surface 18a that engages with the tapered inner surface 23e of the joint member 23 and a locking surface 18b that locks with the elastic locking portion 26.

  In the double pipe joint structure of this embodiment, when the second double pipe 11 moves toward the first double pipe 1, the ring member 18 attached to the outer pipe 12 of the second double pipe 11. Presses the elastic locking portion 26, the elastic locking portion 26 enters the joint member 23 while expanding the diameter. Then, at a position where the distal end surface of the outer tube 12 in the second double tube 11 comes into contact with the end surface of the outer tube 2 in the first double tube 1, the tapered outer surface 18a of the ring member 18 At the same time as engaging with 23e, the elastic locking portion 26 is reduced in diameter and locked on the locking surface 18b of the ring member 18.

  Therefore, the first double pipe 1 and the second double pipe 11 are connected with one touch, and workability can be improved. Moreover, since the ring member 18 comes into contact with the joint member 23 between the tapered surfaces, the airtightness can be improved, and there is no fear that the low-pressure refrigerant flowing in the outer tube leaks to the outside.

  Further, as shown in FIG. 7, instead of the locking groove 12c and the ring member 18 of the outer pipe 12 of the second double pipe 11 in the double pipe joint structure in FIG. The outer tube 12 is beaded to form a bulged portion 12d. The bulging portion 12d is formed with a locking surface 12e capable of locking with the elastic locking portion 26 of the locking member 25, and a tapered outer surface 12f capable of locking with the tapered inner surface 23e of the joint member 23.

  When the second double tube 11 moves toward the first double tube 1, the bulging portion 12d formed on the outer tube 12 of the second double tube 11 forms the elastic locking portion 26. When pressed, the elastic engaging portion 26 enters the joint member 23 while expanding the diameter. The tapered outer surface 12f of the bulging portion 12d is formed at the position where the end surface of the outer tube 12 in the second double tube 11 abuts on the end surface of the outer tube 2 in the first double tube 1. While being engaged with the inner surface 23e, the elastic locking portion 26 is reduced in diameter and locked to the locking surface 12e of the bulging portion 12d.

  In addition, between the inner pipe 3 of the first double pipe 1 and the inner pipe 13 of the second double pipe 11, a bulging portion 12d formed by bead processing of the outer pipe 12 of the second double pipe 11 is provided. Since the second double pipe 13 cannot protrude from the outer pipe 12 of the second double pipe, the bypass inner pipes 7 are inserted and the respective inner pipes 3 and 13 are processed. We will be connecting each other.

  Therefore, the first double pipe 1 and the second double pipe 11 are connected with one touch because only the second double pipe 11 is caused to enter the first double pipe 1. Workability can be improved. In addition, since the bulging portion 12d of the outer tube 12 in the second double tube 11 comes into contact with the joint member 23 between the tapered surfaces, the airtightness can be improved, and the low-pressure refrigerant flowing in the outer tube is discharged to the outside. There is no risk of leakage.

  Next, a double pipe joint structure according to a second embodiment will be described. In this embodiment, as shown in FIG. 8, the joint member 21 in the first embodiment is deleted, and the locking member 25 is directly mounted on the outer tube 32 of the first double tube 31. In this embodiment, the inner tube 3 in the first double tube 31, the outer tube 12 and the inner tube 13 in the second double tube 11, and the locking member 25 are the same as those in the first embodiment. The description of the configuration will be omitted, and the same reference numerals as those in the first embodiment will be added when describing each part as necessary.

  At one end of the outer pipe 32 of the first double pipe 31, a female-side joint part 33 formed to have a larger diameter than the general cylindrical part 32 a is formed to form an outer part of the outer part of the second double pipe 11. The tube 12 can be fitted inside. The female joint portion 33 has an edge portion 33a formed at a distal end portion with a diameter larger than the outer diameter of the general portion of the female joint portion 33. Further, the female joint portion 33 is provided with the locking member 25 adjacent to the edge portion 33a. Insertion grooves 33b through which the elastic locking portions 26 are inserted are formed at a plurality of locations along the circumferential direction.

  The locking member 25 is attached to the outer tube 32 by inserting the elastic locking portion 26 at the distal end into an insertion groove 33b formed in the female joint portion 33 of the outer tube 32. The elastic locking portion 26 is configured to be capable of engaging with the locking groove 12c of the outer tube 12 in the second double tube 11 by elastically expanding and reducing the diameter.

  Therefore, in the double pipe structure of this embodiment, the outer pipe 12 presses the elastic locking portion 26 of the locking member 25 by the movement of the second double pipe 11 to the first double pipe 31 side. By expanding the diameter, the second double pipe 11 enters the female side joint portion 33 of the outer pipe 32 of the first double pipe 31, and the inner pipe 3 of the first double pipe 31 When the inner pipe 13 of the second double pipe 11 is fitted inside and moved to a predetermined position, the elastic locking portion 26 engages with the locking groove 12c of the outer pipe 12. As a result, since the second double pipe 11 only enters the first double pipe 31, the first double pipe 31 and the second double pipe 11 can be connected with one touch. It becomes.

  Since the outer tube 32 of the first double tube 31 and the outer tube 12 of the second double tube 11 are sealed by the O-ring 27 attached to the seal groove 12b of the outer tube 12, The low-pressure refrigerant passing through the outer tube 32 of the first double tube 31 passes through the outer tube 12 of the second double tube 11 in a state where the airtightness is improved without leaking to the outside. The inner pipe 3 of the first double pipe 1 and the inner pipe 13 of the second double pipe 11 are sealed by an O-ring 16 as in the double pipe joint structure of the first embodiment. Therefore, the high-pressure refrigerant passing through the inner pipe 3 of the first double pipe 1 is supplied into the outer pipe 13 of the second double pipe 11 in a state of improving airtightness without leaking to the outside. It becomes.

  Next, a double pipe joint structure according to a third embodiment will be described.

  As shown in FIGS. 9 to 10, the double pipe joint structure of this embodiment is a double pipe joint structure in which either the first double pipe or the second double pipe is a functional member. For example, from one side, a second double pipe is formed by interposing a deformed cylindrical connector member 41 as a two-way branch joint to an expansion valve 8 in which an outer pipe and an inner pipe are branched on different axes. 11 shows a double-pipe joint structure for joining the two pipe joints.

  That is, as shown in FIG. 9, the connector member 41 adjacent to the expansion valve 8 includes a male-side joint portion 42 protruding in a cylindrical shape for insertion into the low-pressure refrigerant port 8 a of the expansion valve 8, and the expansion valve 8. The high pressure refrigerant port 8b and the opening 43 through which the connecting pipe 9 connecting the connector member 41 is provided at one end side, and the second double pipe 51 having a hollow portion 44a at the other end side is provided. It is formed as a female joint 44 to be inserted.

  The low-pressure refrigerant passage 42a in the male-side joint portion 42 is bent in the vertical direction and connected to the hollow portion 44a of the female-side joint portion 44. The opening 43 inserts the connecting pipe 9 and the wall portion 41a of the connector member 41. And is connected to the hollow portion of the female-side joint portion 44. In the connecting pipe 9, the bent portion 9a is inserted into the opening 43 of the connector member 41, and a straight portion extending horizontally upward from the bent portion 9a passes through the wall portion 41a to form the hollow portion of the female joint portion 44. The male joint 9b is disposed so as to be inserted through the inside 44a. A seal groove 9c is formed near the distal end of the male-side joint 9b, and an O-ring 10 is mounted thereon. An O-ring 45 is mounted between the connection pipe 9 and the wall 41a of the connector member 41.

  On the other hand, a locking member 47 is mounted on the outer peripheral surface of the connector member 41. The locking member 47 is formed in a cylindrical shape, and extends along one axis from a first horizontal window portion 48 at an equal interval along the axial direction, and extends from the other end surface. The first horizontal window 48 and the second horizontal window (not shown) are alternately arranged in the circumferential direction. The elastic locking portion 49 is disposed so as to protrude inward from one of the thick portions where the first horizontal window portion 52 or the second horizontal window portion is not formed. The elastic locking portion 49 is attached to the connector member 41 by being inserted into insertion grooves 44b formed at a plurality of locations along the circumferential direction near one end (the female joint portion 44 side) of the connector member 41. Further, the elastic locking portion 49 is formed so as to be able to engage with a locking groove 52b formed in the outer pipe 52 of the second double pipe.

  The connector member 41 end of the outer tube 52 of the second double tube 51 forms a male joint and is formed so as to be insertable into the female joint 44 of the connector member 41. And a locking groove 52b. An O-ring 55 is mounted on the seal groove 52a, and an elastic locking portion 49 is engaged with the locking surface 52b. The inner pipe 53 of the second double pipe 51 is formed so as to form a female joint and insert the male joint 9 b of the connection pipe 9.

  In the double pipe joint structure formed as described above, when the second double pipe 51 moves toward the inside of the female side joint portion 44 of the connector member 41, the outer pipe 52 of the second double pipe 51 is moved. When the distal end portion presses the elastic locking portion 49 of the locking member 47, the distal end portion enters the female joint portion 44 of the connector member 41 while expanding the diameter of the elastic locking portion 49. At the position where the distal end surface of the outer tube 52 in the second double tube 51 reaches the step surface in the female joint portion 44, the elastic locking portion 49 of the locking member 47 is reduced in diameter and the outer tube 52 is And the male joint 9b of the connecting pipe 9 is inserted into the inner pipe 53.

  At this time, the female joint portion 44 of the connector member 41 and the outer tube 52 of the second double tube 51 are sealed by an O-ring 55, and the male joint portion 9b of the connection pipe 9 and the second double tube Since the inner tube 53 is sealed by the O-ring 10 with the inner tube 53, airtightness can be maintained.

  Therefore, the connector member 41 and the second double pipe 51 are connected by one-touch because the second double pipe 51 only needs to enter the female joint portion 44 of the connector member 41. Workability can be improved.

  As described above, according to the double pipe joint structure of the first to third embodiments, the first double pipe 1 (or 31) or the connector member 41 and the second double pipe 11 (or 51) Since the locking member 25 (or 47) including the elastic locking portion 26 (or 49) is mounted on the first double pipe 11 (or 51), the joint member 21, or the connector member 41, The elastic locking portion 26 (or 49) is expanded by making the second double pipe 11 (or 51) enter the first double pipe 1 (or 31), the joint member 21 or the connector member 41. Since the diameter and diameter of the second double pipe 11 (or 51) are locked to the outer pipe 12 (or 52) of the second double pipe 11 (or 51), the second double pipe 11 (or 51) is connected to the first double pipe. 1 (or 31) or the joint member 21 or the connector member 41, The double pipe 1 (or 31) and the second double pipe 11 (or 51) or the connector member 41 and the second double pipe 51 can be connected with one touch, thereby improving workability and cost. Reduction can be achieved.

  Next, a description will be given of a fourth embodiment in which double pipes formed by separately forming the inner pipe and the outer pipe are connected with an inexpensive configuration without brazing or welding. The double-pipe joint structure of this embodiment does not include a locking section having an elastic locking section, and plastically deforms the joint member between the first double pipe and the second double pipe at the joining position. As shown in FIG. 11, an inner tube and an outer tube of a first double tube (not shown) arranged coaxially are branched and joined at their ends at two ends as shown in FIG. FIG. 3 shows a joint structure for connecting a connector member 101 as a joint member and a second double pipe 111 that can be fitted inside the female joint portion 101a of the connector member 101. FIG.

  The connector member 101 accommodates a male joint portion 102 connected to the low-pressure pipe member, an insertion hole 104 connected to the high-pressure pipe member and passing one end of the bypass inner pipe 103, and an outer pipe 112 of the double pipe 111. And a hollow portion 105 formed therein.

  The hollow portion 105 communicates with the low-pressure refrigerant passage 106 of the male joint portion 102, and passes through the other end of the bypass inner pipe 103 extending from the pipe insertion port 107 formed in the inlet side wall of the connector member 101. Let me. The bypass inner pipe 103 inserted into the hollow portion 105 has a seal groove 103 a formed at a portion supported by the pipe insertion port 107 of the connector member 101, and an O-ring 108 is attached to seal the gap with the connector member 101. Make up the structure. On the terminal side of the bypass inner tube 103, a seal groove 103 b is formed, an O-ring 109 is mounted, and the O-ring 109 is fitted inside the inner tube 113 of the double tube 111.

  An end of the outer tube 112 of the double tube 111 on the connector member 101 side forms a male joint portion 112a, and a seal groove 112b and a joining groove 112c are formed in this order from the terminal side. An O-ring 115 is attached to the seal groove 112b to form a seal structure with the connector member 101, and an end portion 101b of the female joint portion 101a of the connector member 101 is formed by mouth drawing in the joint groove 112c. Joined by

  On the other hand, the inner tube 113 of the double tube 111 forms a female joint portion 113b whose end portion on the connector member side is larger in diameter than the general tubular portion 113a, and the end portion of the bypass inner tube 103 is fitted inside. The distal end of the female-side joint portion 113b is formed to have a large diameter by flaring to guide the end of the bypass inner pipe 103 so as to be easily inserted.

  In the above-described double pipe joint structure, one end of the bent bypass inner pipe 103 is inserted into the insertion groove 104 of the connector member 101, and the other end on which the O-rings 108 and 109 are mounted is inserted into the connector member 101. After the pipe 101 is inserted through the pipe insertion port 107, the inner pipe 103 is caulked and connected between the insertion groove 104 of the connector member 101, and then the double pipe 111 is inserted into the female joint 101 a of the connector member 101. Then, the outer pipe of the double pipe 111 is fitted inside the female joint part 101a, and the end of the bypass inner pipe 103 is fitted inside the female joint part 113b of the inner pipe 113. Then, the end portion 101b of the connector member 101 is crimped and joined to the joining groove 112c of the outer tube 112 by mouth drawing.

  In the double pipe joint structure according to this embodiment, when connecting the outer pipe 112 and the inner pipe 113 formed separately to the second double pipe 111 to the connector member 101, the edge portion 101 b of the connector member 101 is connected to the outer pipe 112 and the inner pipe 113. Since it is connected by joining to the outer tube 112 by plastic working, the double tube 111 and the connector member 101 can be performed without brazing or welding, thereby improving workability. It can be done at low cost.

  Next, a double pipe joint structure according to a fifth embodiment will be described.

  This embodiment shows a configuration in which the first double pipe and the second double pipe are tightened with a screw member to press-connect the two double pipes to each other, as shown in FIG. On one end side of the outer tube 122 of the first double tube 121, a sealing groove 122a and a locking groove 122b are formed in order from the terminal side, and an O-ring 125 is mounted on the sealing groove 122a. A ring member 128 formed of a resin material is attached to 122b. On one end side of the inner pipe 123 in the first double pipe 121, a seal groove 123a is formed near the end, and an O-ring 126 is mounted.

  On the other hand, on one end side of the outer tube 132 of the second double tube 131, a sealing groove 132a and a locking groove 132b are formed in order from the terminal side, and an O-ring 135 is mounted on the sealing groove 132a. One end of a cylindrical locking ring 138 is locked to 132b. Opposite end faces of the outer tube 122 of the first double tube 121 and the outer tube 132 of the second double tube 131 are formed so as to be able to abut each other. The inner pipe 133 of the second double pipe 131 has a female joint 133b whose tip is larger in diameter than the general tubular section 133a, and the end of the inner pipe 123 of the first double pipe 121 is inserted. It is possible.

  The locking ring 138 that engages with the locking groove 132b of the outer tube 132 in the second double pipe 131 includes a locking portion 138a that engages with the locking groove 132b, and a first double ring from the locking portion 138a. It has a ring portion 138b extending toward the pipe 121 and an expanding portion 138c formed on the distal end side of the ring portion 138b. The expansion portion 138c is formed by a tapered portion 138d extending to the tip and a locking surface 138e abutting on the side surface of the ring member 128, and the outer surface of the tapered portion 138d is formed as a tapered outer surface 138f.

  A union nut 141 and a union male portion 145 are arranged on the outer peripheral surfaces of the ring member 128 and the locking ring 138 so as to sandwich the ring member 128 and the locking ring 138.

  The union nut 141 is formed at one end with a flange portion 142 having an insertion groove 142a through which the outer tube 122 of the first double tube 121 is inserted. The body portion is formed in a cylindrical shape and screwed with the union male portion 145. The female screw portion 143 is formed on the inner wall surface. An inner wall surface of the flange portion 142 forms a locking surface 142b that can be locked to a side surface of the ring member 128.

  The union male portion 145 is formed in a cylindrical shape having an insertion groove 145 a through which the locking ring 138 is inserted, and has a male screw portion 146 and a rotation operation portion 147 having a larger diameter than the male screw portion 146 on the outer peripheral surface. And is formed to be screwable with the female screw portion 143 of the union nut 141. The distal end portion of the male screw portion 146 forms a locking surface 146a and a tapered inner surface 146b capable of locking with the tapered portion 138d of the locking ring 138.

  Then, the ring member 128 is mounted on the locking groove 122 b of the second double pipe 131, and the locking ring 138 is mounted on the locking groove 132 b of the outer pipe 132 of the second double pipe 131. Through the outer tube 122 of the first double tube 121, and the union male part 145 through the outer peripheral surface of the locking ring 138 attached to the second double tube 131. The outer tube 122 and the outer tube 132 of the second double tube 131 are brought into contact with each other. The inner pipe 123 of the first double pipe 121 is inserted into the female joint 133b formed in the inner pipe 133 of the second double pipe 131.

  In this state, the union male part 145 is fastened to the union nut 141 by rotating the rotation operation part 147 of the union male part 145 clockwise. By tightening the union male part 145, the union male part 145 moves to the union nut 141 side, and the locking surface 146a and the tapered inner surface 146b are locked to the tapered part 138d of the locking ring 138, and the tapered part 138d is formed. The ring member 128 is pressed against the ring member 128, and the locking surface 142 b of the union nut 141 is locked on the outer wall surface of the ring member 128 to press the ring member 128 against the locking ring 138.

  Thereby, the first double pipe 121 and the second double pipe 131 are tightly connected.

  Therefore, also in the double pipe joint structure according to this embodiment, when connecting the first double pipe 121 to the second double pipe 131, the union male portion 145 is tightened to the union nut 141, and the first Since the double pipe 121 and the second double pipe 131 can be formed without brazing or welding, the workability can be improved and the cost can be reduced.

  As described above, the double-pipe joint structure of the present invention provides a double pipe in which the inner pipe and the outer pipe are formed separately from each other, for example, as shown in the first to third embodiments. A coupling means including a locking member having a portion, a configuration in which the elastic locking portion is elastically deformed by entering the second double pipe into the first double pipe so as to be connected with one touch, As shown in the fourth embodiment, after the first double pipe and the second double pipe are arranged at the joining position, the joint member is connected to the first double pipe and the second double pipe. It is arranged so as to cover the end and is connected by plastic deformation, or as shown in the fifth embodiment, is arranged at a position where the first double pipe and the second double pipe are joined. After that, since the first double pipe and the second double pipe are connected by tightening with a screw means, brazing or welding work is performed. Ku, the cost can be reduced by improving the workability.

  In addition, since the inner pipe and the outer pipe are formed separately and connected by the connecting means in each of the double pipes, it is necessary to project the inner pipe from the outer pipe when the inner pipe is inserted into the outer pipe. This can be easily performed without performing extra processing of scraping off the tip of the outer tube. Therefore, a significant cost reduction can be performed.

  Note that the double pipe joint structure of the present invention is not limited to the above-described embodiment. For example, as shown in FIG. 13 or FIG. 14, the second double pipe 151 is attached to the end of the first double pipe 151. After inserting the end of the double-walled pipe, the double pipe is fastened by a fastening member 155 having a substantially W-shaped cross section which is formed in two parts by fin joints and is configured to be openable and closable. You may comprise so that a double pipe and a 2nd double pipe may be connected.

  At this time, as shown in FIG. 13, the fastening member 155 locks one end to a step surface of an expanding female side joint portion 152 a formed at an end portion of the outer tube 152 of the first double tube 151, The other end is locked to a resin ring member 165 integrally formed by outsert into a locking groove 162a formed in the outer pipe 162 of the second double pipe 161. It is desirable that the locking surfaces at both ends of the fastening member 145 are formed in a tapered shape.

  As shown in FIG. 14, a bulge 182a formed by beading is formed on the outer tube 182 of the second double tube 181 in place of the ring member 165 of FIG. You may comprise so that it may fasten by the fastening member 175 which divided | segmented the substantially W-shaped cross section. In addition, between the inner pipe 173 of the first double pipe 171 and the inner pipe 183 of the second double pipe 181, the outer pipe 172 of the first double pipe 171 is formed in an expanded shape. In order to process the bulging portion 182a by beading the female joint portion 172a and the outer tube 182 of the second double tube 181, the respective inner tubes 173 project from the respective outer tubes 172. Since it is impossible to do so, the bypass inner pipe 176 is inserted to connect the respective inner pipes 173 and 183.

  Although each of the double pipes in the double pipe joint structure of the above-described embodiment has been described in which the outer pipe and the inner pipe are formed separately, it is needless to say that they may be formed integrally. In this case, as shown in FIG. 15, the outer tube 2 and the inner tube 3 are connected from the inner tube 3 by a curved fin portion 4a or by a not-shown "L-shaped" support. Is also good.

  Further, as shown in FIG. 16, the end of the double pipe 1 in which the outer pipe 2 and the inner pipe 3 are integrally formed, the sealing groove 2b or the locking groove 2c of the outer pipe 2 is formed by mouth drawing. The end portion of the inner tube 3 is formed with a female-side joint portion 3b and a tapered surface 3c that are expanded from the general tubular portion 3a by mouth-opening processing. Both can be manufactured at low cost because they are formed by plastic deformation of the outer tube 2 and the inner tube 3.

  Furthermore, the double-pipe joint structure of the present invention can be applied not only to a vehicle but also to an air conditioner installed in a structure such as a building.

  Next, when connecting the double pipes or the double pipes to the two-way branch joint, if the connection is made via the bypass inner pipe, the inner pipe of the double pipe will be expanded. Therefore, each of the shapes having a shape that facilitates the opening process of the inner pipe will be described.

  In the sixth mode, in order to insert the bypass inner pipe into the inner pipe of the double pipe, the flaring process is performed on one end of the inner pipe. To form.

  For example, when integrally forming the inner tube and the outer tube, as shown in FIG. 15, the inner tube 3 and the outer tube 2 are connected by a support (hereinafter referred to as a fin) 4 and formed by extrusion. It will be. At this time, when the tip of the double pipe is widened, it is difficult to perform the widening if the strength of the column is strong. Therefore, as shown in FIG. The fin portion 204 formed integrally with the inner tube 203 is formed so as to extend in a tangential direction of the inner tube from a position divided into three on the inner peripheral surface of the outer tube. As a result, when the distal end of the inner pipe is widened, the reaction force against the force in the radial direction of the inner pipe is smaller than when the fin portion 204 is formed so as to face the axis of the inner pipe 203. Since a component force is generated, the size is reduced, and the flaring process is facilitated.

  In the double tube 204A as shown in FIG. 19, the fin portion 204a is brought into contact with the tangential direction of the inner tube 203 and the bent portion 204b is provided between the fin portion 204a and the outer tube 202. Thus, the reaction force can be absorbed and can be easily performed.

  Further, in the double tube 201B shown in FIG. 20A, one end of the fin portion 204 extending from the outer tube 202 is formed at two symmetrical positions so as to extend in the tangential direction of the inner tube 203, In the double pipe 202C shown in FIG. 20B, one end of the fin portion 204 extending from the outer pipe 202 may be formed at one location so as to extend in the tangential direction of the inner pipe 203. .

  According to FIG. 21, the thickness of the fin portion is regulated. In the double tube 201D of FIG. 21A, the fin portion 204 is formed to extend from the three-part position on the inner peripheral surface of the outer tube 202 toward the tangential direction of the inner tube 203, and the thickness of the fin portion 204 is increased. The thickness T3 is smaller than the thickness T2 of the inner tube 203, and the thickness T2 of the inner tube 203 is smaller than the thickness T1 of the outer tube 202. In the double tube 201E of FIG. 21B, the fin portion 204 is formed from the three-part position on the inner peripheral surface of the outer tube 202 toward the axis of the inner tube 203, and the plate thickness T3 of the fin portion 204 is The thickness of the tube 203 is smaller than the thickness T2, and the thickness of the inner tube 203 is smaller than the thickness T1 of the outer tube 202.

  As described above, in order to increase the diameter of the inner tube 203 by changing the shape of the fin portion 204, the force received by the fin portion 204 from the inner tube 203 is reduced, or the inner tube 203 is formed in consideration of the thickness T. By reducing the force received from the inner tube 203, the opening of the tip of the inner tube 203 of the double tube 201 can be easily performed.

  In the double pipe joint structure according to the seventh embodiment, a two-way branch joint is attached to one end of the double pipe, and a pair of pipe members (high-pressure pipe and low-pressure pipe) separately piped from the double pipe are used. It is a structure for connecting. In this embodiment, as shown in FIG. 22, a bypass inner pipe 207 attached to the distal end of the inner pipe 203 and extending from the inner pipe 203 is provided in the double pipe 201. The end surfaces of the outer tube 202 and the inner tube 203 are formed substantially in the same plane, and the inner tube 203 has a bypass inner tube 207 extending concentrically with the inner tube 203.

  On the other hand, a two-way branch joint 210 is attached to the outer tube 202 so as to cover the distal end of the outer tube 202. The two-way branch joint 210 has a main body 211 extending in a pipe shape along the axis of the double pipe 201, and small diameters arranged side by side in a direction orthogonal to the axis of the main body 211. A branch protrusion 212 having a hole 213 and a large-diameter hole 214 is formed.

  The outer tube 202 of the double tube 201 is fitted inside the inner peripheral surface at one end of the main body 211 via an O-ring 206, and the distal end of the main body 201, that is, the insertion of the double tube 201 is inserted. The mouth portion 211a is located in a concave groove portion 202a formed in the outer tube 202 in the circumferential direction, is reduced in diameter by mouth drawing, and is locked in the concave groove portion 202a. The main body central portion 211b is connected to the distal end of the outer tube 202 and is formed in a hollow shape, and is connected to a large-diameter hole 214 orthogonal to the axis of the main body portion 211.

  The other end of the main body portion 211 is formed in a thick portion 211c adjacent to the main body central portion 211b. A small-diameter hole 213 is formed in the thick portion 211c so as to extend from an end surface of a branch protrusion 212 formed to be orthogonal to the axis of the main body 211. Then, the other end of the bypass inner pipe 207 having one end inserted into the inner pipe 202 is inserted into the thick portion 211c, thereby communicating the small diameter hole 213 with the inner pipe.

  Thereby, the double pipe 201 can connect the inner pipe 203 and the outer pipe 303 to the small-diameter hole 213 and the large-diameter hole 214 of the two-way branch joint, respectively, and connect the high-pressure pipe to the small-diameter hole 213. By connecting the low pressure pipe to the large diameter hole 214, the branch pipe and the double pipe can be connected in one cycle.

  The two-way branch joint 210 is disposed, for example, at a joint with a double pipe when a double pipe is connected to an evaporator for a rear seat from a part of a pipe in a refrigeration cycle disposed in an engine room. Will be done. Thus, when piping a long distance from the engine room to the rear part of the vehicle body, the double pipe 201 can save the cost, and it is possible to save the piping members and save the piping space.

  FIG. 23 shows the two-way branch joint 210A in which the small-diameter hole 213 and the large-diameter hole 214 in FIG. 22 are formed in the male-side joint portions 215 and 216, respectively. The distance is longer than the two-way branch joint 210 of FIG. Also in this embodiment, a bypass inner pipe 207 is disposed at the distal end of the inner pipe 203, and is fitted into the thick portion 211d of the two-way branch joint 210A. The distal end of the two-way branch joint 210A on the double pipe 201 side is reduced in diameter by a drawing process in a concave groove 202b formed in the outer pipe 202, and is joined to the outer pipe 202.

  Therefore, also in the double pipe joint structure in which the double pipe shown in FIG. 22 or FIG. 23 is connected to the two-way branch joint, similar to the form shown in FIG. 9 and FIG. Thereby, the double pipe and the two-way branch joint can be easily joined without joining them by brazing or welding, so that workability can be improved.

  In an eighth mode, the inner pipes of two double pipes are connected to each other by a bypass inner pipe, and can be connected to the outer pipe by a quick joint. As illustrated in FIG. 24, the quick joint 220 includes a joint member (same configuration as the joint member 21 illustrated in FIGS. 1 and 2) 221 and a locking member (same configuration as the locking member 25 illustrated in FIGS. 1 and 2). 225 are provided. 1 by connecting the inner pipe 233 of the first double pipe 231 and the inner pipe 243 of the second double pipe 241 by the bypass inner pipe 227. 2 are longer than those shown in FIGS.

  Of the two double tubes 231 and 241, two concave grooves 232a and 232b are formed in the circumferential direction at two locations in the vicinity of the tip of the outer tube 232 in one of the double tubes 231. The concave groove (joining tip side) 232b is a seal groove, on which an O-ring 235 is mounted. One end of a cylindrical joint member 221 is attached to the other concave groove 232a with its diameter reduced by mouth drawing.

  The inner pipe 233 of the first double pipe 231 and the inner pipe 243 of the second double pipe 241 have ends 233a and 243a facing each other having a larger diameter than the general cylindrical sections 233b and 243b by opening. Formed. Then, both ends of the bypass inner pipe 227 are fitted inside the ends 233 a and 243 a formed to have a large diameter, and the inner pipe 233 of the first double pipe 231 and the inner pipe 243 of the second double pipe 241 are connected. Are connected.

  The bypass inner pipe 227 is formed in a cylindrical shape, and a concave groove 227a is formed on a part of a part to be inserted into each of the inner pipes 233 and 243, and the O-rings 227 and 227 are respectively attached. The airtightness between the inner pipes 233 and 243 is improved.

  One end of the joint member 221 formed in a cylindrical shape fits the outer tube 232 of the first double tube 231 and then is drawn toward the concave groove 232 a formed in the outer tube 232 by mouth drawing. The other end is provided with an edge 221b formed with a diameter larger than the outer diameter of the general portion, and the other end 221b has a slot-like insertion groove 221c along the circumferential direction. Are formed at a plurality of locations.

  The locking member 225 is formed in a cylindrical shape, and extends along the axial direction from a first horizontal window portion (not shown) extending from one end surface at equal intervals, and extends from the other end surface. It has a second horizontal window (not shown), and the first horizontal windows and the second horizontal windows are alternately arranged along the circumferential direction. An elastic locking portion 226 is arranged on one of the thick portions where the first horizontal window portion or the second horizontal window portion is not formed so as to protrude inward.

  On the other hand, in the outer pipe 242 of the second double pipe 241, two concave grooves 242 a and 242 b are formed over the entire circumference at a portion inserted into the joint member 221. An O-ring 245 is mounted in the concave groove 242a on the distal end side, and a C-ring 246 capable of locking the elastic locking portion 226 of the locking member 225 is mounted in the other concave groove 242b. The outer peripheral surface of the C-ring 246 is formed in a tapered shape that spreads from the front side (the first double tube 231 side) to the rear side (the surface opposite to the first double tube 231). The locking surface of the elastic locking portion 226 of the C ring 246 is a rear surface.

  Next, the operation of connecting the second double pipe 241 in the above-described double pipe joint structure to the first double pipe 231 via the quick joint 220 will be described with reference to FIGS.

  With respect to the first double pipe 231 in which the quick joint 220 is mounted on the outer pipe 232 and the bypass inner pipe 227 is mounted on the inner pipe 233, the second double pipe 231 is disposed at a position separated from the first double pipe 231. The tip of the double pipe 241 is brought closer to the quick joint 220, and the tip of the second double pipe 241 is inserted into the joint member 221.

  When the second double pipe 241 further enters the inside of the joint member 221, the C-ring 246 mounted on the outer pipe 242 of the second double pipe 241 passes through the joint member 221 as shown in FIG. The elastic locking portion 226 of the locking member 225 inserted into the groove portion 221c is brought into contact with the elastic locking portion 226, and the elastic locking portion 226 is pressed by the outer peripheral tapered surface of the C-ring 246 to bend in a direction to increase the diameter.

  When the second double pipe 241 further enters the inside of the joint member 221 toward the first double pipe 231, as shown in FIG. 26, the C ring 246 exceeds the elastic locking portion 226, and Since the stop portion 226 is not pressed by the C-ring 246, the diameter thereof is reduced by the elastic force and is locked to the rear surface of the C-ring 246. In this position, the end 243a of the inner pipe 243 of the second double pipe 241 is regulated by the tip of the bypass inner pipe 227 (on the side of the second double pipe 241), the movement is stopped, and the first pipe 241 is stopped. Of the double pipe 241 and the second double pipe 241 will be joined.

  As described above, when the first double pipe 231 and the second double pipe 241 are joined, they can be joined with one-touch by fitting them through the quick joint 220. Moreover, in any of the double pipes 231 and 241, the end faces of the outer pipes 232 and 242 and the inner pipes 233 and 243 are flush with each other by connecting the two inner pipes 233 and 243 by the bypass inner pipe 227. Since it is possible, it is possible to omit an unnecessary process of notching the distal ends of the outer tubes 232 and 242, and it is possible to reduce the cost.

  In the ninth embodiment, instead of the quick joint 220 of the eighth embodiment, a nut member is provided around the outer pipe of the first double pipe.

  As shown in FIG. 27, the outer tube 252 of the first double tube 251 has a seal groove 252a and a concave groove 252b in order from the end face near the joint with the outer tube 262 of the second double tube 261. Is formed. An O-ring 255 is mounted on the seal groove 252a, and a stepped cylindrical member 256 is mounted on the concave groove 252a by spinning. The stepped cylindrical member 256 has a small-diameter portion 256a and a large-diameter portion 256b, and is arranged such that the large-diameter portion 256b is close to the distal end side and the small-diameter portion 256a is located behind the large-diameter portion 256b.

  At the rear end of the stepped cylindrical member 256 mounted on the outer tube 252 of the first double tube 251, there is disposed a nut member 270 to which the end face of the small diameter portion 256 a can abut. The first double pipe 251 and the second double pipe 261 are connected by engaging the union member 280 attached to the double pipe 261.

  The union member 280 mounted on the second double tube 261 is formed in a stepped cylindrical shape, and is provided at the side end of the first double tube 251 with a male screw portion 281 screwed to the female screw portion 271 of the nut member 270. Is formed, and the distal end surface is formed so as to be able to contact the end surface of the large diameter portion 256b of the cylindrical member 256 mounted on the first double pipe 251. Furthermore, a hexagonal union portion 282 is provided at the center, and a thin small-diameter portion 283 is formed at the rear end of the union portion 282. The small-diameter portion 283 is formed on the outer tube 262 of the second double tube 261. After the outer fitting, the diameter of the union member 280 is reduced by mouth drawing, and the union member 280 is integrally attached to the outer pipe 262 of the second double pipe 261.

  A seal groove 262a and a concave groove 262b are formed in the outer pipe 262 of the second double pipe 261. An O-ring 265 is mounted on the seal groove 262a to improve airtightness. The small diameter portion 283 of the union member 280 is joined by mouth drawing.

  Also, the distal ends of the inner pipe 253 of the first double pipe 251 and the inner pipe 263 of the second double pipe 261 are widened to bypass the widened portions 253a and 263a of the two inner pipes 253 and 263. The inner pipe 257 is inserted and the inner pipes 253 and 263 are connected.

  Further, the stepped cylindrical member 256 attached to the first double pipe 251 by spinning in FIG. 27 may be a C-ring 258 having one end opened as shown in FIG. 28, or As shown in FIG. 29, a cylindrical member 259 attached by mouth drawing may be used.

  The bypass inner pipe 7 used in the first embodiment (see FIG. 7), the bypass inner pipe 103 used in the fourth embodiment (see FIG. 11), the bypass inner pipe 176 shown in FIG. 7 (see FIGS. 22 and 23), the bypass inner pipe 227 used in the eighth embodiment (see FIG. 24), and the bypass inner pipe 227 used in the ninth embodiment (see FIG. 27). As shown in FIG. 30A, the inner pipe 257 of the bypass has seal grooves 301a, 301a formed at both ends of the cylindrical member 301 by mouth drawing, and O-rings 302, 302 are respectively formed in the seal grooves 301a, 301a. 30 (b), two-color molding with rubber members 312, 312 disposed at both ends of a resin cylindrical member 311 as shown in FIG. 30 (b). To do Made but, of course, not limited to these.

  Further, as shown in FIGS. 31 and 32, the bypass inner pipe 7 (103, 176, 207, 227, 257) can be held by the holding ring 310. The retaining ring 310 includes an outer ring portion 311, an inner ring portion 312, and a fin portion 313 that is divided into three parts along the tangential direction of the inner ring portion 312 from the outer ring portion 312 to the inner ring portion 312. The inner ring portion 312 having a predetermined width H is externally fitted to the outer peripheral surface of the bypass inner pipe 7 (103, 176, 207, 227, 257), and the outer peripheral surface of the outer ring portion 311. Is supported on the inner peripheral surface of a predetermined member (a member disposed on the outer peripheral surface when the holding ring 310 is disposed at the center of the bypass inner pipe 7 (103, 176, 207, 227, 257)). .

  The holding ring 310 is not limited to the above. For example, as shown in FIG. 33, the holding ring 310 is formed by removing the inner ring portion 312 and forming the outer ring portion 311 and three fin portions 313. The ring 310A may be used.

1 is a partial cross-sectional view illustrating a double pipe joint structure according to a first embodiment of the present invention. It is II-II sectional drawing in FIG. FIG. 3 is a sectional view taken along the line III-III in FIG. 2. It is sectional drawing which shows the support member which connects an inner tube and an outer tube. FIG. 4 is a partial cross-sectional view showing a connection operation between a first double pipe and a second double pipe. It is a partial sectional view showing another form which connects a 1st double pipe and a 2nd double pipe. It is a partial sectional view showing another form of the double pipe joint structure by a 1st form. It is a partial sectional view showing the double pipe joint structure by a 2nd form. It is a partial sectional view showing the double pipe joint structure by a 3rd form. It is a top view in FIG. It is a partial sectional view showing the double pipe joint structure by a 4th form. It is a partial sectional view showing the double pipe joint structure by a 5th form. It is a partial sectional view showing the double pipe joint structure by other modes. It is a partial sectional view showing the double pipe joint structure by other modes. It is sectional drawing which shows the double pipe formed integrally. It is a partial sectional view showing end processing of a double pipe. It is a partial sectional view showing the conventional double pipe joint structure. It is sectional drawing which shows the double pipe | tube by 6th form. It is sectional drawing of the double pipe | tube which shows another form. It is sectional drawing of the double pipe | tube which shows the same another form. It is sectional drawing of the double pipe | tube which shows the difference of the thickness dimension of each part. It is sectional drawing which shows the structure which connects a double pipe to a two way branch joint. It is sectional drawing which shows the same another form. It is sectional drawing which shows the form which connects two double pipes via a bypass inner pipe. FIG. 25 is an operation diagram in FIG. 24. FIG. It is sectional drawing which shows the form which connects two double pipes with a screw means. FIG. 28 is a cross-sectional view showing a part of FIG. 27 in another form. It is sectional drawing which shows a part in FIG. 27 by another form. It is sectional drawing which shows a pipe in a bypass. FIG. 4 is a partial cross-sectional view showing a form in which a bypass inner pipe is held by a holding ring. FIG. 32 is a view as viewed from the direction indicated by the arrow A in FIG. 31. FIG. 33 is a front view showing another form of the retaining ring in FIG. 32.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 1st double pipe 2 outer pipe 2c locking groove 3 inner pipe 3b female joint part 5 O-ring 7 bypass inner pipe 11 2nd double pipe 12 outer pipe 12c locking groove 12d bulging part 13 inner pipe 15 O-ring 16 O-ring 18 Ring member 21 Joint member (joint means)
21a Joint 21c Inserting groove 25 Locking member (joint means)
25a first horizontal groove portion 25b second horizontal groove portion 26 elastic locking portion 28 support member (connection means)
28a annular portion 28b spiral fin portion 32 outer tube 33 female joint portion 41 connector member 47 locking member 49 elastic locking portion 101 connector member 128 ring member 138 locking ring 141 union nut 145 union male portion 201 first two Heavy pipe 202 Outer pipe 203 Inner pipe 204 Fin part 207 Bypass inner pipe 210 Two-way branch joint 220 Quick joint 221 Joint member 225 Locking member 227 Bypass inner pipe 231 First double pipe 232 Outer pipe 233 Inner pipe 241 Second Double tube 242 Outer tube 243 Inner tube 251 First double tube 252 Outer tube 253 Inner tube 256 Stepped cylindrical member 257 Bypass inner tube 258 C ring 259 Cylindrical member 261 Second double tube 262 Outer tube 263 Inside Pipe 270 Nut member 280 Union member

Claims (30)

An inner pipe that circulates a high-pressure fluid is piped inside an outer pipe that circulates a low-pressure fluid, and the inner pipe and the outer pipe are formed integrally or separately from each other and connected by connecting means. A double pipe joint structure for connecting two double pipes,
The first double pipe and the second double pipe are connected by joint means,
When one of the first double pipe and the second double pipe enters the other double pipe, the joint means is elastically deformed so that the inside of one of the double pipes is deformed. A double pipe joint structure wherein the first double pipe and the second double pipe can be connected so as to be able to enter the joint means. The joint means has one end joined to the first double pipe by plastic deformation means and fitted to each outer pipe. The joint means is attached to the joint member and is connected to the outside of the second double pipe. It comprises a locking member that can be locked to the tube,
When the locking member locks the outer tube of the second double tube, the locking member includes an elastic locking portion that can be expanded by being pressed by the outer tube of the second double tube,
As the outer tube of the second double tube enters the joint member, the inner tube of the second double tube enters the joint member, and the elastic locking portion of the locking member At the position where the outer tube of the second double tube is locked, the inner tube of the first double tube and the inner tube of the second double tube are in a fitted position. The double pipe joint structure according to claim 1, wherein:   The double pipe joint according to claim 2, wherein the joint member is formed in a cylindrical shape, and a plurality of insertion grooves for inserting the elastic locking portions of the locking member is formed in a circumferential direction. Construction.   The double pipe joint structure according to claim 2, wherein the joint member is joined to a groove formed in the outer pipe of the first double pipe in a circumferential direction by mouth drawing. .   The locking member is formed in a cylindrical shape, and has a first horizontal window extending from one end face at equal intervals along the axial direction and a second horizontal window extending from the other end face. The first horizontal window and the second horizontal window are alternately arranged in the circumferential direction, and the first horizontal window or the second horizontal window is provided. 5. The double-pipe joint structure according to claim 2, wherein the elastic locking portion is arranged on one of the thick portions where no is formed.   The outer tube of the second double tube has circumferentially formed grooves that can be locked to the elastic locking portions of the locking member. Double pipe joint structure.   A ring member attached to a groove formed in the outer tube of the second double tube is interposed between the outer tube of the second double tube and the elastic locking portion. The double pipe joint structure according to claim 2, wherein   3. The outer tube of the second double tube is formed with a bulging portion having a diameter larger than that of a general cylindrical portion and capable of being locked by the elastic locking portion. The double pipe joint structure as described. The joint means extends through the female joint formed in the first double pipe and a plurality of insertion grooves formed in the female joint in a circumferential direction. A locking member that can be locked to the outer pipe of the heavy pipe,
The locking member includes an elastic locking portion that can be expanded by being pressed by the outer tube of the second double tube when locking the outer tube of the second double tube, The double pipe joint structure according to claim 1, wherein the inner pipe of the second double pipe is arranged so as to be fitted to the inner pipe of the first double pipe. An inner pipe that circulates a high-pressure fluid is piped inside an outer pipe that circulates a low-pressure fluid, and the inner pipe and the outer pipe are formed integrally or separately and are connected by connecting means. A double pipe joint structure for connecting the heavy pipe to another pipe member via a joint means,
The coupling means is connected to a high-pressure pipe for circulating a high-pressure fluid and a low-pressure pipe for circulating a low-pressure fluid on one side, and is connected to the inner pipe and the low-pressure pipe communicating with the high-pressure pipe on the other side. A two-way branch joint that is connected to the double pipe having an outer pipe that connects to the pipe, and a locking member that has one end attached to the two-way branch joint and the other end that can lock the outer pipe of the double pipe. With
The locking member includes an elastic locking portion that can be inserted into an insertion groove formed in a circumferential direction of the two-way branch joint and locked to an outer pipe of the double pipe,
When the locking member locks the outer tube of the double tube, the elastic locking portion is formed to be expandable by being pressed by the outer tube of the double tube, A double pipe joint structure, wherein an inner pipe is arranged so as to be able to fit into the inner pipe of the two-way branch joint. An inner pipe that circulates a high-pressure fluid is piped inside an outer pipe that circulates a low-pressure fluid, and the inner pipe and the outer pipe are formed integrally or separately from each other and connected by connecting means. A double pipe joint structure for connecting two double pipes,
The first double pipe and the second double pipe are connected by joint means,
When the first double pipe and the second double pipe are in the joining position, the joint means is joined to either of the double pipes by plastic deformation means, or the double pipe is joined by the fastening means. A double pipe joint structure, wherein the first double pipe and the second double pipe are connected by fastening pipes. An inner pipe that circulates a high-pressure fluid is piped inside an outer pipe that circulates a low-pressure fluid, and the inner pipe and the outer pipe are formed integrally or separately from each other and connected by connecting means. A double pipe joint structure for connecting two double pipes,
The first double pipe and the second double pipe are connected by joint means,
The joint means includes screw means, and when the first double pipe and the second double pipe are at a joint position, the first double pipe is tightened by tightening the screw means. A double pipe joint structure, wherein a heavy pipe and the second double pipe are pressed against each other to connect the first double pipe and the second double pipe.   The said connection means is provided with the fin part which supports so that the said inner pipe | tube and the said outer pipe | tube may be connected in the radial direction. , 9, 10, 11 or 12.   The end of one of the inner pipe of the first double pipe and the inner pipe of the second double pipe has an enlarged diameter portion that is enlarged from a general cylindrical portion. , 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13.   The double-pipe joint structure according to claim 13, wherein the fin portion is formed so as to extend in a plurality of spirals from the inner pipe toward the inner peripheral surface of the outer pipe.   The double pipe joint structure according to claim 13, wherein the fin portion extends the inner pipe side end from the outer pipe side end toward a position eccentric from the axis of the inner pipe. .   The double pipe joint structure according to claim 13, wherein the fin portion is formed to be bent between the inner pipe and the outer pipe.   The double pipe joint structure according to claim 16 or 17, wherein the fin portion is formed to be thicker than an inner pipe and thinner than an outer pipe. An inner pipe that circulates a high-pressure fluid is piped inside an outer pipe that circulates a low-pressure fluid, and the inner pipe and the outer pipe are formed integrally or separately from each other and connected by connecting means. A double pipe joint structure for connecting two double pipes through joint means,
Opposite distal ends of the inner pipe of the first double pipe and the inner pipe of the second double pipe are formed to have a larger diameter than the inner diameter of the general cylindrical section by opening, and each inner pipe is formed. A double pipe joint structure, wherein the pipes are connected by bypass inner pipes fitted between the distal ends of the respective inner pipes. An inner pipe that circulates a high-pressure fluid is piped inside an outer pipe that circulates a low-pressure fluid, and the inner pipe and the outer pipe are formed integrally or separately and are connected by connecting means. A double pipe joint structure for connecting a heavy pipe to a two-way branch joint having an inner pipe inlet and an outer pipe inlet,
The distal end of the inner pipe of the double pipe is formed to have a diameter larger than the inner diameter of the general cylindrical section by opening processing, and is connected to an inner pipe inlet formed in the two-way branch joint by a bypass pipe. A double pipe joint structure.   The coupling means is configured to have an elastic locking member that is elastically deformed so as to be able to expand and contract in diameter when one of the double pipes is inserted, so that the double pipe can be inserted instantaneously. The double pipe joint structure according to claim 19, wherein:   A first screw means attached to the first double pipe and having an internal thread, and a second screw attached to the second double pipe and having an external threaded portion which can be screwed with the internal thread. 20. The means according to claim 19, further comprising: means for connecting the first double pipe to the second double pipe by screwing the male screw to the female screw. Heavy pipe joint structure.   20. The double-pipe joint structure according to claim 19, wherein a restricting means for restricting a position of the first screw means is provided on an outer pipe of the first double pipe.   24. The double pipe joint structure according to claim 23, wherein the restricting means is a C-ring mounted on an outer pipe of the first double pipe.   The double pipe joint structure according to claim 23, wherein the restricting means is a cylindrical member attached to an outer pipe of the first double pipe by spinning.   24. The double pipe joint structure according to claim 23, wherein the restricting means is a cylindrical member mounted on the outer pipe of the first double pipe by a drawing process.   The double pipe joint structure according to claim 22, wherein the second screw means has a union part formed in a hexagonal shape and capable of engaging with a tool.   21. The double-pipe joint structure according to claim 19, wherein an O-ring is attached to a seal groove formed at both ends of the bypass inner pipe by spinning.   21. The double pipe joint according to claim 19, wherein the bypass inner pipe is formed by two-color molding using a resin-made pipe member and rubber members disposed at both ends of the pipe member. Construction. The said bypass inner pipe is hold | maintained by the holding ring which has a fin part and supported the outer peripheral surface, The 19,20,21,22,23,24,25,26,27,20. 29. The double pipe joint structure according to 28 or 29.

Images