JP5346890B2 - Double pipe joint structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate connecting the inner pipe of a double tube in which part of outer pipe and inner pipe are made common without deteriorating flowability fluid. <P>SOLUTION: The double pipe 1 in which the inner pipe 12 is arranged in the outer pipe 11 and the outer pipe 11 and the inner pipe 12 are integrally formed by making part of them common is the connected. The hole 16 for connecting is bored in the common part 13 of the outer pipe 11 and the inner pipe 12. The hole 16 is incomplete bored holes having an uncut portion in the part. The cut piece 17 where the hole 16 is formed is obliquely projected into the inside of the inner pipe 12 so as to make an acute angle to the axial line of the hole 16. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a double pipe joint structure for connecting a double pipe in which an inner pipe is disposed inside the outer pipe and a fluid such as liquid or gas is circulated in each of the outer pipe and the inner pipe. Belonging to the field.

  Recently, double pipes have been widely used in a wide range of industrial fields in order to make the fluid flow path compact, and various improvements have been attempted in the relative arrangement structure of the outer pipe and the inner pipe. Along with this, various improvements have also been attempted in the joint structure of the double pipe for connecting the double pipe.

  Conventionally, as a joint structure of a double pipe, the thing of patent documents 1 is known, for example.

  Patent Document 1 discloses a double pipe joint structure in which a connecting hole is drilled in an outer pipe having an inner pipe disposed in the center, and the outer pipe connecting pipe is connected in a direction perpendicular to the axis of the outer pipe. Have been described.

  The joint structure of the double pipe according to Patent Document 1 is connected to the outer pipe connected to the outer pipe by closing the inner pipe by connecting the outer pipe to the outer pipe connecting pipe at a location not subject to the restriction of the inner pipe. It is possible to connect to the flange and facilitate the connection of the inner pipe.

  Conventionally, as a double pipe, the thing of patent document 2 is known, for example.

  Patent Document 2 describes a double tube in which a metal plate is bent and an outer tube and an inner tube are integrally formed.

  In the double pipe according to Patent Document 2, a part of the outer pipe and the inner pipe are made common, the amount of manufacturing material is reduced, and the manufacturing cost is reduced.

JP 2001-235081 A Japanese Utility Model Publication No. 48-57715

  The joint structure of the double pipe according to Patent Document 1 is applied to the connection of the inner pipe of the double pipe according to Patent Document 2, and is connected to the common part of the outer pipe and the inner pipe of the double pipe according to Patent Document 2. When the hole is drilled, the inner tube is closed at the end, but a useless gap is formed between the drilled hole and the closed end, and the fluid is trapped or disturbed. There is a problem that the distribution is impaired.

  The present invention has been made in consideration of such problems, and easily connects the inner pipe of a double pipe in which a part of the outer pipe and the inner pipe are made common without impairing the fluidity of the fluid. It is an object of the present invention to provide a double pipe joint structure that can be used.

  In order to solve the above-described problems, the double pipe joint structure according to the present invention employs means described in each of the claims.

  That is, in claim 1, the inner tube is disposed inside the outer tube, and the outer tube is connected to a double tube formed by integrating a part of the inner tube. A hole for connection is drilled in the common part of the inner pipe, and the hole is incomplete with an uncut part in part, and the cut piece forming the hole is connected to the inner pipe from the common part of the outer pipe and the inner pipe. It is characterized by extending so as to protrude inside.

  In this means, the joint structure of the double pipe according to Patent Document 1 is applied to the connection of the inner pipe of the double pipe according to Patent Document 2, and a cut piece having a connection hole formed in the inner pipe is connected to the outer pipe, A rectifying plate that projects from the common part of the inner pipe to the inside of the inner pipe to block the gap formed between the hole in which the cut piece is perforated and the end port to be closed, thereby preventing fluid accumulation and disturbance. Function as.

  According to a second aspect of the present invention, there is provided the double pipe joint structure according to the first aspect, wherein the cut piece is inclined upstream of the fluid flow in the inner pipe so as to have an acute angle with respect to the axis of the hole. To do.

  In this means, the fluid flowing through the inner pipe is smoothly guided to the connection hole by the inclined cutting piece.

  According to a third aspect of the present invention, in the double pipe joint structure according to the first or second aspect, the inner pipe has a side wall extending from the common part of the outer pipe and the inner pipe in parallel with the radial direction of the inner pipe. The back wall facing the common part of the outer and inner pipes at the back end is a semi-circular shape with the cross-sectional shape protruding outward rather than expanding the gap between the side walls, and the cut piece is common to the outer and inner pipes The portion is cut into a U-shape.

  In this means, the inner pipe is formed in a tunnel shape on the side wall and the back wall, so that when the hole for connection is drilled by a press type drilling work, the cut piece is smoothly guided in the back direction on the side wall. Collision with each part of the inner pipe is avoided, and it is possible to avoid the formation of useless gaps in the rear wall that is not expanded more than the side wall.

  According to a fourth aspect of the present invention, in the double pipe joint structure according to the third aspect, the cut piece is in contact with a side wall and a back wall of the inner pipe.

  With this means, the gap can be almost completely closed with the cut piece by performing brazing because the cut piece is brought into contact with the side wall and the back wall of the inner tube.

  The double pipe joint structure according to the present invention is a double pipe joint structure according to Patent Document 1 applied to the connection of the double pipe inner pipe according to Patent Document 2, and a connection hole is provided in the inner pipe. By protruding the formed cut piece from the common part of the outer and inner pipes into the inner pipe, the gap formed between the hole in which the cut piece is perforated and the end port to be closed is blocked, and the stagnation of the fluid Since it functions as a rectifying plate that prevents accumulation and disturbance, it has the effect of easily connecting the inner pipe of a double pipe with a common part of the outer pipe and inner pipe without impairing the fluidity of the fluid. .

  Furthermore, as claimed in claim 2, the fluid flowing through the inner pipe is smoothly guided to the connection hole by tilting the cut piece, so that the fluid flow of the inner pipe of the double pipe is more reliably ensured. There is an effect that the connection can be made without any damage.

  Furthermore, as claimed in claim 3, when the inner tube is formed in a tunnel shape at the side wall and the back wall, when the hole for connection is drilled by a press type drilling work, the cut piece is smoothly moved to the back side by the side wall. Because it avoids the formation of useless gaps in the back wall that is guided and avoids collision with each part of the inner pipe and is not expanded more than the side wall, it is possible to accurately cut the cut piece with the press-type drilling machine. There is an effect that it can be inclined and arranged inside.

  Further, as claimed in claim 4, since the cut piece is brought into contact with the side wall and the back wall of the inner tube, the gap can be almost completely closed by the cut piece by performing brazing. This has the effect of more reliably preventing stagnation and disturbance.

It is a longitudinal cross-sectional view of the form for implementing the joint structure of the double pipe concerning this invention. It is the XX sectional view taken on the line of FIG. It is an enlarged side view of the principal part (double pipe) of FIG. It is a perspective view which shows the manufacture example of FIG. FIG. 4 is a perspective view of the drilling work example of FIG. 3. FIG. 6 is an enlarged longitudinal sectional view of FIG. 5.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the joint structure of the double pipe which concerns on this invention is demonstrated based on drawing.

  In this embodiment, a structure is shown in which a double pipe 1 formed with a relatively small diameter suitable for use as a refrigerant passage of an in-vehicle air conditioner is connected.

  As shown in FIG. 1, this embodiment is composed of each part of a double pipe 1, an inner pipe connection pipe 2, an outer pipe connection pipe 3, and a connection flange 4.

  As shown in detail in FIG. 3, the double pipe 1 includes an outer pipe 11 and an inner pipe 12.

  As shown in FIG. 4, the outer tube 11 and the inner tube 12 are integrally formed by directly extruding an aluminum-based metal material having good thermal conductivity from an extrusion die (die) D, and the inner tube 12. Is arranged inside the outer tube 11. When used as a refrigerant passage or the like of an in-vehicle air conditioner, the fluid flowing through the outer pipe 11 is a gas obtained by vaporizing the refrigerant, and the fluid flowing through the inner pipe 12 is a refrigerant liquid. Accordingly, the outer tube 11 is a low-pressure tube and the inner tube 12 is a high-pressure tube, but the thickness a of the outer tube 11 is set to be larger than the wall thickness b of the inner tube 2 in consideration of the overall rigidity. Yes (see FIG. 3).

  The outer tube 11 of the double tube 1 is formed in a true circular cross section.

  As apparent from FIG. 3, the inner tube 12 of the double tube 1 is formed in a tunnel shape in cross section. In the tunnel shape of the inner tube 12, a side wall 121 extends from the common portion 13 in parallel with the radial direction of the inner tube 12 with a part of the arc shape of the outer tube 11 (common portion 13) as a front wall. The back wall 122 is formed by facing the back wall 122 as a semicircular shape in which the cross-sectional shape of the common portion 13 protrudes outward (backward direction) at the back end of 121. A boundary portion between the inner side surface 121a of the side wall 121 and the common portion 13 is formed on a small curved surface 14 which is the minimum curved surface necessary for extrusion processing. A boundary portion between the outer surface 121 b of the side wall 121 and the outer tube 11 is formed on the curved surface 15.

  For the double pipe 1, as shown in FIGS. 5 and 6, when performing a press-type drilling work for connecting the inner pipe 12 to the common portion 13 of the outer pipe 11 and the inner pipe 12, naturally. However, the punch P having a size within the range of the interval between the side walls 121 of the inner pipe 12 is selected. The shape of the cutting blade of the punch P is inclined (see FIG. 6) so that the cutting plane is U-shaped (see FIG. 5) and the U-shaped base Pa side protrudes from the U-shaped open part Pb side. Yes. Note that a blade having a cutting function is not provided at the edge of the punch P on the U-shaped opening portion Pb side.

  The punch P is pressed from the outside of the common portion 13 in the radial direction of the outer tube 11 and the inner tube 12, and a hole 16 for connection is drilled in the common portion 13, and a cut piece 17 generated along with the drilling is formed in the back direction. It will be pushed in (in the direction of the inner wall 122 of the inner tube 12). The punch P is positioned on the side of the end ports 111 and 123 where the U-shaped open portion Pb side becomes the connection end of the outer tube 11 and the inner tube 12.

  At this time, the boundary portion between the inner surface 121a of the side wall 121 of the inner tube 12 and the common portion 13 is formed on the small curved surface 14, and the stress of cutting the punch P is easily concentrated, so that the common portion 13 is easily cut. Thus, the hole 16 is reliably formed. The hole 16 has a U-shape (tongue piece shape, horseshoe shape) due to the shape of the cutting blade of the punch P, etc., and an incomplete perforation in which the U-shaped open portion side is left as an uncut portion in the common portion 13. Become. Therefore, as the hole 16 is drilled, the cut piece 17 is pushed into the inner tube 12 and protrudes into the inner tube 12 so that the U-shaped base side is inclined with the U-shaped open portion side as a fulcrum. That is, the cut piece 17 is disposed at an acute angle with respect to the axis of the hole 16 and is inclined toward the upstream side of the fluid flowing through the inner tube 12.

  Further, since the cut pieces 17 pushed by the punch P are guided on both sides so as to slide on the inner side surface 121a by the side walls 121 of the inner pipe 12, the inner pipe 12 is damaged by the cut pieces 17 or the cut pieces 17 are The pipe 12 is not pressed and fixed. Further, since the U-shaped base side that is the tip of the cut piece 17 pushed by the punch P is directed to the inner wall 122 that is not expanded more than the side wall 121 of the inner pipe 12, the gap between the cut piece 17 and the inner pipe 12 is reached. No useless gaps are formed.

  Therefore, when the press-type drilling work for connecting the inner tube 12 to the common portion 13 of the outer tube 11 and the inner tube 12 is performed, there is no problem due to the cut piece 17.

  The cut piece 17 pushed into the inner tube 12 is brought into contact with the side wall 121 and the back wall 122 of the inner tube 12. For this reason, it is possible to obtain a substantially complete plugging structure with respect to the inner tube 12 by performing brazing.

  As shown in FIGS. 1 and 2, the inner pipe connecting pipe 2 is connected to the drilled hole 16 by brazing. The inner pipe connecting pipe 2 is connected and supported by the connecting flange 4. This connection is the technology itself of the double pipe joint structure according to Patent Document 1, and can be easily implemented.

  Furthermore, the end 123 of the inner tube 12 is crimped and brazed to the outer tube 11 and the common portion 3 in an arc shape by crushing. As a result, a gap 18 is formed between the end port 123 of the inner tube 12 and the aforementioned cut piece 17. The gap 18 is almost completely closed.

  Further, the outer pipe connecting pipe 3 is fitted and connected to the end port 111 of the outer pipe 11 by brazing. The outer pipe connecting pipe 3 is connected and supported in common by the connecting flange 4 to which the inner pipe connecting pipe 2 is connected and supported.

  If this form is used, since the inner wall 122 of the inner tube 12 is semicircular and has pressure resistance, the function of the inner tube 12 as a high-pressure tube is reliably ensured.

  Furthermore, since the inner pipe 12 is configured to support the back wall 122 with the side wall 121 that is two legs, the inner pipe 12 is not crushed even if the pipe is twisted. Therefore, a degree of freedom can be obtained in the piping work.

  Further, since the boundary between the outer surface 121b of the side wall 121 of the inner tube 12 and the outer tube 11 is formed on the curved surface 15 and the narrow gap S (see FIG. 3) is not formed, the fluid inside the outer tube 11 is formed. Is not hindered. Note that the curved surface 15 reinforces the side wall 121 of the inner tube 12 and also exhibits twist resistance against the above-described twisted piping.

  Further, the fluid flowing through the inner pipe 12 and flowing into the inner pipe connecting pipe 2 is guided to the cutting piece 17 and smoothly changed direction. Moreover, since the gap 18 at the back of the cut piece 17 is almost completely closed, the fluid does not stagnate or disturb in the vicinity of the cut piece 17. Therefore, high fluidity is ensured for the fluid flowing through the inner pipe 12 and the inner pipe connecting pipe 2.

  As described above, it is possible to change the high-pressure pipe and the low-pressure pipe of the outer pipe 11 and the inner pipe 12 in addition to the illustrated form, and accordingly the thicknesses a and b can be changed as appropriate.

  Furthermore, the present invention can also be applied when the outer tube 11 is non-circular.

  Furthermore, the shape of the inner wall 122 of the inner tube 12 can be a shape other than a semicircular shape.

  Further, the inclination angle of the cut piece 17 is a range in which a void 18 is formed on the end 123 side of the inner tube 12 and a new reservoir portion of fluid is not formed (an angle parallel to the axis of the hole 16). It is possible to set by.

  When the embodiment for carrying out the double pipe joint structure according to the present invention is used as a refrigerant passage of an in-vehicle air conditioner, the double pipe 1 has an outer diameter of 19 mm and a wall thickness a. The inner tube 2 has a thickness of 1.0 mm, the interval between the inner surfaces 21a of the side walls 21 is 5 mm, and the center of the back wall 22 is set at a position away from the center of the outer tube 1 by 4.61 mm. .

  The joint structure of a double pipe according to the present invention can be used for applications other than the refrigerant passage of an in-vehicle air conditioner, and can be applied when formed in a considerably large diameter.

DESCRIPTION OF SYMBOLS 1 Double pipe 11 Outer pipe 12 Inner pipe 121 Side wall 122 Back wall 13 Common part 16 Hole 17 Cutting piece 2 Inner pipe connection pipe 3 Outer pipe connection pipe 4 Connection flange

Claims (4)

  An inner tube is arranged inside the outer tube, and the outer tube and the inner tube are connected to a common part of the outer tube and the inner tube, and a part of the inner tube is integrally formed. A hole is drilled, and the hole is incomplete with a part that is not cut, and the cut piece that forms the hole extends from the common part of the outer and inner pipes so as to protrude into the inner pipe. A double pipe joint structure characterized by   2. The double pipe joint structure according to claim 1, wherein the cut piece is inclined to the upstream side of the flow of the fluid in the inner pipe so as to have an acute angle with respect to the axis of the hole. .   3. The double pipe joint structure according to claim 1, wherein the inner pipe is an outer pipe, a side wall extending from a common portion of the inner pipe in parallel with the radial direction of the inner pipe, and an outer pipe at the back end of the side wall. The inner wall facing the common part of the inner pipe is not expanded beyond the interval between the side walls, and the cross-sectional shape is a semicircular shape protruding outward, and the cut piece is cut into a U-shape at the common part of the outer pipe and the inner pipe A double pipe joint structure characterized by   4. The double pipe joint structure according to claim 3, wherein the cut piece is in contact with a side wall and a back wall of the inner pipe.

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