JP2008157505A - Double tube, connecting structure of double tube and double tube joint, and brazing method of double tube and double tube joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce costs and labor-hour by preventing defective brazing in an inner tube inside of a double tube joint. <P>SOLUTION: In this double tube A constituted by coaxially disposing the inner tube 2 and an outer tube 1 double, projecting a tip portion of the inner tube 2 from a tip of the outer tube 1, and melting a ring-shaped brazing filler metal 4 for the inner tube and a ring-shaped brazing filler metal 5 for the outer tube mounted on the tip portion 2c of the inner tube 2 and the tip portion 1a of the outer tube 1 to be brazed to the double tube joint, a projection 2a for restricting the movement of the brazing filler metal 4 for the inner tube in the direction separating from a tip 2b of the inner tube 2 along the inner tube 2, is disposed on the tip portion 2c of the inner tube 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is suitable for use in piping of a vehicle air conditioner, and is a double pipe in which an inner pipe and an outer pipe are integrally formed substantially coaxially by extrusion or drawing, and the double pipe. The present invention relates to a coupling structure with a double pipe joint, and a brazing method between the double pipe and the double pipe joint.

2. Description of the Related Art Conventionally, in an in-vehicle air conditioner, a low-pressure gaseous refrigerant and a high-pressure liquid refrigerant are respectively used in a reverse direction by using a single double pipe in which an inner pipe and an outer pipe are integrally formed. What was made to flow is known (for example, refer to patent documents 1).
In this prior art, each of the inner pipe and the outer pipe of the double pipe is brazed to the double pipe joint.
This brazing is performed according to the following procedure.
First, a ring-shaped brazing material for an inner tube and a brazing material for an outer tube are respectively attached to the outer circumferences of the inner tube and the outer tube of the double pipe. Next, when the inner pipe and the outer pipe of the double pipe are inserted into the double pipe insertion hole of the double pipe joint and the tip of the outer pipe is abutted against the stopper of the double pipe, each brazing material is doubled. It arrange | positions in the contact state to the opening peripheral part of the inner tube insertion hole and outer tube insertion hole of a pipe joint. In this state, each brazing material is heated and melted to perform brazing.
JP 2003-287166 A

However, in the above-described prior art, positioning is performed based on the position of the outer pipe of the double pipe with respect to the double pipe joint, and the inner pipe and the outer pipe are brazed. There is a possibility that the position of the brazing material for the inner pipe that is disposed in the position of the inner pipe is shifted, and the double pipe joint may not be properly brought into contact with the double pipe joint.
Moreover, since this inner pipe brazing material cannot be visually observed inside the double pipe joint, it is difficult to find this when a brazing failure occurs.
Therefore, in order to prevent such a brazing defect from occurring, it is necessary to keep the component accuracy and the mounting position accuracy of each brazing material high, and the difference in inserting the double pipe into the double pipe joint. It is also necessary to manage the loading speed, resulting in an increase in cost and labor.

  The present invention has been made paying attention to the conventional problems as described above, and prevents the occurrence of brazing failure in the inner pipe inside the double pipe joint, thereby reducing cost and labor. It is an object of the present invention to provide a double pipe, a coupling structure of a double pipe and a double pipe joint, and a brazing method of the double pipe and the double pipe joint.

In order to achieve the above object, according to the first aspect of the present invention, the inner tube and the outer tube are coaxially arranged in an inner and outer double, and the distal end portion of the inner tube projects from the distal end of the outer tube. A double pipe that is fused to a double pipe joint by melting a ring-shaped brazing material attached to the tip of the inner pipe and the tip of the outer pipe, and is attached to the tip of the inner pipe The double pipe is characterized in that stopper means for restricting the brazing material from moving along the inner pipe in a direction away from the inner pipe is provided.
Further, the invention according to claim 2 is provided in a double pipe insertion hole for inserting a double pipe, and a bottom wall which is a contact portion of the double pipe insertion hole, and a tip portion of the inner pipe An inner pipe insertion hole into which the inner pipe is inserted, an inner pipe communication passage formed continuously with the inner pipe insertion hole and communicated with an inner pipe flow path inside the inner pipe, and the double pipe insertion hole. Provided at the opening side end, an outer tube insertion portion into which the outer tube is inserted when the distal end portion of the inner tube is inserted into the inner tube insertion hole, and the double tube insertion hole. An outer pipe communication path formed and communicated with an outer pipe flow path inside the outer pipe, and a double pipe joint comprising:
A double pipe and a double pipe joint combined with the double pipe,
The outer pipe is brazed to the opening peripheral edge of the double pipe insertion hole in a state where the outer pipe is inserted into the outer pipe insertion portion of the double pipe insertion hole, and the inner pipe is inserted into the inner pipe insertion The inner pipe brazing material is melted and the double pipe joint and the inner pipe are brazed between the opening peripheral edge of the inner pipe insertion hole and the stopper means while being inserted into the hole. It was made into the joint structure of the double pipe and double pipe joint characterized by these.
The invention according to claim 3 is a brazing method between the double pipe and the double pipe joint, wherein a ring-shaped brazing material for the inner pipe is attached to the outer periphery of the tip of the inner pipe, and A step of attaching a ring-shaped outer tube brazing material to the outer periphery of the outer tube tip, and inserting the double tube into the double tube insertion hole of the double tube joint; The inserted inner pipe brazing material is inserted into the inner pipe insertion hole until it abuts against the abutting wall and is sandwiched between the stopper means and the distal end portion of the outer pipe is inserted into the outer pipe difference. A step of positioning the double pipe and both brazing materials by bringing the outer pipe brazing material into contact with the outer peripheral edge of the double pipe insertion hole, and melting the both brazing materials to double pipe And brazing the double pipe joint to the double pipe joint. It was put method.

In the present invention, the double pipe is provided with stopper means for restricting the movement of the ring-shaped inner pipe brazing material attached to the outer periphery of the front end portion of the inner pipe along the inner pipe in a direction away from the front end of the inner pipe. It was.
For this reason, when the double pipe is inserted into the double pipe joint, the double pipe is inserted until the brazing material for the inner pipe attached to the outer periphery of the tip of the inner pipe hits the opening edge of the inner pipe insertion hole of the double pipe. When the plug is inserted, the movement of the brazing material for the inner pipe is restricted, so that the insertion of the double pipe is also restricted, so that the positioning of the double pipe can be performed. It is securely in contact with the bottom wall of the pipe joint.
On the other hand, the brazing material for the outer pipe mounted on the outer periphery of the outer pipe is located outside the double pipe joint and can be visually observed.If the mounting position is incomplete, the position can be corrected by visual inspection. It is possible, and the brazing material for the outer pipe can also be brought into contact with the peripheral edge of the opening of the double pipe insertion portion of the double pipe joint.

  In this way, when the double pipe is positioned and the position of the brazing material for the outer pipe is confirmed, both brazing materials are melted and the double pipe is brazed to the double pipe joint.

As described above, according to the present invention, the brazing material for the inner pipe and the brazing material for the outer pipe can be reliably brought into contact with the double pipe joint, so that the occurrence of brazing failure can be prevented.
Moreover, since the brazing material for the inner pipe is melted and brazed between the opening peripheral edge of the inner pipe insertion hole at the bottom of the double pipe joint and the stopper means provided in the inner pipe, It is possible to suppress the spread of the brazing material when it is melted and to perform brazing more firmly.
Furthermore, prevention of the occurrence of this brazing failure can be achieved by providing a stopper means on the inner pipe, and it is possible to increase the accuracy of parts and work as in the past, and to manage the insertion speed of the double pipe. This makes it possible to reduce costs and labor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the double pipe of this embodiment, the inner pipe (2) and the outer pipe (1) are coaxially arranged inside and outside the double pipe, and the tip (2c) of the inner pipe (2) is connected to the outer pipe ( Ring brazing material (4, 5) protruding from the tip (1b) of 1) and attached to the tip (2c) of the inner tube (2) and the tip (1a) of the outer tube (1) In the double pipe joint (B), the brazing material (4) is connected to the inner pipe (2) at the tip (2c) of the inner pipe (2). The double pipe is characterized in that stopper means (2a) is provided for restricting the movement in the direction away from the tip (2b) of the inner pipe (2) along 2).

  Below, based on FIGS. 1-5, the double pipe A, the coupling structure of the double pipe A and the double pipe joint B, and the double pipe A of Example 1 of the best mode of the present invention A brazing method with the double pipe joint B will be described.

  First, before describing the first embodiment, the vehicle air conditioner AC to which the first embodiment is applied will be briefly described.

As shown in FIG. 5, the vehicle air conditioner AC includes a front seat air conditioning unit FAU disposed in the front portion of the vehicle and a rear seat air conditioning unit RAU disposed in the rear portion of the vehicle.
In addition, each air conditioning unit FAU, RAU has a blower fan 101, 201 that forms the air flow, an evaporator 102, 202 that cools the air flow, a heater core 103, 203 that heats the air flow, and a blowing rate of the cold air and the hot air. And air mix doors 104 and 204 for adjusting the temperature of the blown air by adjusting.

  Both evaporators 102 and 202 are connected to a compressor 301, a condenser 302, a liquid tank 303, and expansion valves 304 and 305 by a circulation pipe 306 to constitute a cooling cycle.

  Further, the circulation pipe 306 branches at a branching portion 306 a downstream of the liquid tank 303 into a front branch circulation path 307 toward the expansion valve 304 and the evaporator 102 and a rear branch circulation path 308 toward the expansion valve 305 and the evaporator 202. Has been. Further, the front branch circulation path 307 and the rear branch circulation path 308 are joined at a junction 306 b upstream of the compressor 301.

  The front branch circulation path 307 and the rear branch circulation path 308 are respectively compared in the evaporators 102 and 202 with the high-temperature refrigerant passages 307a and 308a through which the relatively high-temperature and high-pressure liquid refrigerant flowing out from the liquid tank 303 flows. And low-temperature refrigerant passages 307b and 308b through which the refrigerant in the form of a low-temperature and low-pressure gas flows.

  Here, a double pipe A is used in a portion forming the rear branch circulation path 308, and double pipe joints B and B are coupled to both ends of the double pipe A.

  The double pipe joints B and B connected to both ends of the double pipe A and the coupling structure thereof are the same. Therefore, in describing the double pipe A and the double pipe joint B, branching will be described below. What is provided in the side near the part 306a and the junction part 306b is demonstrated.

As shown in FIG. 4, the double pipe A is formed by extrusion or drawing from a metal such as aluminum, and the outer pipe 1 and the inner pipe 2 are coaxially arranged inside and outside the outer pipe. 1 is divided into an outer space 1 s and an inner space 2 s by an inner tube 2. Further, the outer tube 1 and the inner tube 2 are connected by a connecting rib 3 and formed integrally.
In the first embodiment, the connecting rib 3 is provided by dividing the outer space 1 s into three in the circumferential direction. Moreover, the outer diameter of the outer tube 1 is, for example, about 16 to 25 mm in diameter, and the outer diameter of the inner tube 2 is formed, for example, to about 6 to 12 mm.

  In FIG. 4, the double pipe A shows a state at the time of manufacturing by extrusion or drawing, but as shown in FIG. 1, the outer pipe 1 and the connecting rib 3 are formed at both ends of the double pipe A. The inner pipe 2 is removed and processed so as to be exposed by a preset dimension L1. In addition, the position which removes the outer tube | pipe 1 and the connection rib 3 in the both ends of the double tube | pipe A is shown with the dashed-two dotted line CUT in FIG.

  FIG. 1 shows a double pipe A of Example 1, in which a plurality of protrusions 2a as stopper means are formed on the same circumference from the tip of an inner pipe 2 at a position of a preset dimension L2. Yes. These protrusions 2a are formed by deforming the inner tube 2 from the inner side to the outer diameter direction, and the protrusion margin is a ring-shaped inner tube brazing member used for brazing the inner tube 2 to the double pipe joint B. The material 4 is formed in a dimension capable of restricting movement of the material 4 in the axial direction of the inner tube 2 and away from the tip 2 b of the inner tube 2.

  The double pipe joint B connects the two divided high-temperature refrigerant passages 308a and low-temperature refrigerant passages 308b to the outer space portion 1s and the inner space portion 2s disposed inside and outside the double tube A. FIG. As shown, a double pipe insertion hole 11, an inner pipe insertion hole 12, an inner pipe communication path 13, and an outer pipe communication path 14 are provided.

  The double pipe insertion hole 11 is for inserting the double pipe A, and is formed from one end face 10a of the double pipe joint B. The outer pipe 1 is connected to the end on the opening 11a side. An outer tube insertion portion 11b is formed which is expanded to be slightly larger in diameter than the outer diameter of the outer tube 1 so that it can be inserted.

The inner tube insertion hole 12 is a hole formed to have a slightly larger diameter than the inner tube 2 so that the distal end portion 2c of the inner tube 2 can be inserted, and is a portion where the double tube insertion hole 11 abuts. The bottom wall 15 is opened coaxially with the double tube insertion hole 11.
As shown in FIG. 3, the periphery of the opening end of the inner tube insertion hole 12 to the bottom wall 15 is chamfered or rounded at the corners thereof, and the diameter is increased slightly by slanting or bending. A portion 12a is formed.

  As shown in FIG. 2, the inner pipe communication passage 13 is drilled from the end face 10 c opposite to the one end face 10 a of the double pipe joint B until it communicates with the inner pipe insertion hole 12 coaxially with the inner pipe insertion hole 12. The formed inner diameter is formed by three holes 13a, 13b, and 13c whose diameter is reduced stepwise. When the double pipe A is joined, it communicates with the inner space 2s, and the rear branch circuit 308 It is connected to a pipe that forms the high-temperature refrigerant passage 308a.

  The outer pipe communication passage 14 is opened and drilled in the end face 10b adjacent to the one end face 10a of the double pipe joint B, and is substantially orthogonal to the tip of the double pipe insertion hole 11. When A is joined, it is connected to the outer space 1 s and connected to a pipe forming the low-temperature refrigerant passage 308 b of the rear branch circulation path 308.

  In the combined state of the double pipe A and the double pipe joint B shown in FIG. 2, the double pipe A is inserted into the double pipe insertion hole 11 of the double pipe joint B, and the inner pipe 2 is The outer tube 1 is inserted into the tube insertion hole 12 and the outer tube insertion portion 11b. The inner tube 2 is brazed to the opening peripheral edge of the inner tube insertion hole 12 of the bottom wall 15 by the inner tube brazing material 4 attached to the outer periphery thereof, and the outer tube 1 is connected to the outer tube at one end face 10a. 1 is brazed to the peripheral edge of the opening 11a of the double pipe insertion hole 11 by a brazing material 5 for the outer pipe attached to the outer periphery of 1.

Next, the brazing method of the double pipe A and the double pipe joint B of Example 1 will be described.
The first step is a step of attaching both brazing materials 4 and 5 to the double pipe A.
That is, as shown in FIG. 1, the outer tube brazing material 5 is mounted on the outer periphery of the distal end portion 1 a of the outer tube 1, and the inner tube brazing material 4 is mounted on the outer periphery of the distal end portion 2 c of the inner tube 2. At this time, the brazing filler metal 4 is disposed at a position where it is inserted from the tip 2c and abuts against the protrusion 2a. On the other hand, the brazing material 5 for the outer tube is disposed at a position of a predetermined dimension L3 from the tip 1b of the outer tube 1.

The next step is a step of inserting the double pipe A into the double pipe joint B.
In this step, the one end face 10a of the double pipe joint B shown in FIG. 2 is directed upward, and the opening 11a of the double pipe insertion hole 11 is directed upward.
Next, the double pipe A is inserted into the double pipe insertion hole 11. At the same time as inserting the distal end portion 2c of the inner tube 2 into the inner tube insertion hole 12, the outer tube 1 is inserted into the outer tube insertion portion 11b, and the inner tube brazing material 4 attached to the inner tube 2 is It strikes against the periphery of the opening of the inner tube insertion hole 12 of the wall 15.
In this state, since the inner pipe brazing material 4 is restricted from moving in the axial direction in the direction away from the tip 2b of the inner pipe 2 by the projection 2a, the movement in the insertion direction of the double pipe A is also restricted. Tube A is positioned.

  Then, with the double pipe A positioned, the outer pipe brazing material 5 is brought into contact with the periphery of the opening 11a of the double pipe insertion hole 11 on the one end face 10a as shown in the figure. Therefore, the dimension L3 in FIG. 1 is set so that the outer pipe brazing material 5 is disposed at a position where it abuts against the one end face 10a when positioning the double pipe A. The outer pipe brazing material 5 is visually observed during this positioning. Therefore, the dimension L3 is set to be large including a positioning error, and the outer pipe brazing material 5 does not contact the one end face 10a before the inner pipe brazing material 4 contacts the bottom wall 15. Set the dimensions. When the double pipe A is positioned, if there is a gap between the outer pipe brazing material 5 and the one end face 10a, the outer pipe brazing material 5 is moved manually and brought into contact with the one end face 10a. .

The next step is a brazing step.
That is, both brazing materials 4 and 5 are heated to braze the inner pipe 2 and the outer pipe 1 to the double pipe joint B.
At this time, since the receiving part 12a is formed at the periphery of the opening of the inner pipe insertion hole 12, the inner pipe brazing material 4 flows into the receiving part 12a, and the inner pipe 2 of the inner pipe brazing material 4 is connected to the inner pipe 2. The contact area with the heavy pipe joint B increases, and high brazing strength is obtained.

As described above, in the first embodiment, the ring-shaped inner tube brazing material 4 attached to the outer periphery of the distal end portion 2 c of the inner tube 2 regulates the movement in the axial direction away from the distal end 2 b of the inner tube 2. A protrusion 2a was provided.
For this reason, when the double pipe A is inserted into the double pipe joint B, the positioning of the double pipe A is performed in a state in which the brazing material 4 for the inner pipe is securely in contact with the bottom wall 15 to be brazed. It can be carried out.

  For this reason, it is possible to securely braze the inner pipe brazing material 4 to the double pipe joint B and prevent the occurrence of brazing failure. In addition, since the outer tube brazing material 5 attached to the outer periphery of the outer tube 1 is visible, it is possible to prevent the occurrence of brazing defects.

  In addition, since the occurrence of this brazing failure can be prevented simply by deforming the inner tube 2 and forming the projections 2a, it is not necessary to increase the accuracy of the parts or to control the insertion speed as in the conventional case. Thus, cost and labor can be reduced.

  Furthermore, in Example 1, since the receiving part 12a was formed in the periphery of the opening of the inner tube insertion hole 12 in the bottom wall 15 to which the inner tube 2 is brazed, when the inner tube brazing material 4 is melted, the receiving portion 12a is formed. It flows into the part 12a, the contact area of the brazing material with respect to the inner pipe 2 and the double pipe joint B can be increased, and high brazing strength is obtained.

  Next, a double pipe 2A of Example 2 of the embodiment of the present invention will be described with reference to FIG. Since the second embodiment is a modification of the first embodiment, only the difference will be described, and the description of the same configuration and operational effects as the first embodiment will be omitted.

The double pipe 2A of the second embodiment is an example in which an annular protrusion 22a is provided as a stopper means for restricting the movement of the brazing material 4 for the inner pipe.
That is, the inner tube 22 has an annular protrusion that is deformed so that the inner tube 2 protrudes in the outer circumferential direction from the tip 2b to the position of the same dimension L2 as the first embodiment at the tip 2c. 22a is formed.

When the annular protrusion 22a is used, when the inner pipe brazing material 4 is melted in the brazing process, the inner pipe brazing material 4 is restricted from moving in the direction away from the bottom wall 15 over the entire circumference. Since the inner pipe brazing material 4 is brought into contact with the annular protrusion 22a on the entire circumference, the contact area is increased, and higher brazing strength can be obtained.
Since the other functions and effects are the same as those of the first embodiment, description thereof is omitted.

  As described above, the embodiment of the present invention and Examples 1 and 2 have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment and Examples 1 and 2, and the present invention is not limited thereto. Design changes that do not depart from the gist are included in the present invention.

  For example, in the first and second embodiments, the present invention is applied to the vehicle air conditioner AC. However, the present invention can be applied to other vehicle devices or industrial devices other than vehicles.

  In the first and second embodiments, the projection 2a and the annular projection 22a as the stopper means are formed by deforming the inner tubes 2 and 22. However, a brazing member separate from the inner tube is brazed. It may also be added by adhesion or the like.

  In the first and second embodiments, the stopper means protruded from the outer periphery of the inner pipes 2 and 22 in the outer diameter direction. However, as long as the movement of the inner pipe brazing material 4 is restricted in the axial direction. A groove-shaped means recessed in the inner diameter direction may be used. Also in this case, if the inner pipe brazing material 4 is fixed to the concave stopper means by caulking and the inner pipe brazing material 4 protrudes from the outer periphery of the inner pipe 2, it is the same as in the first and second embodiments. The effect of this can be obtained.

It is a side view which shows the double pipe A of Example 1 of the best form of this invention. 2 is a cross-sectional view showing a coupling state of the double pipe A and the double pipe joint B of Example 1. FIG. It is an expanded sectional view of the principal part of FIG. It is a perspective view which shows the state at the time of manufacture by the extrusion process and drawing process of the double pipe A of Example 1. FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a structure explanatory drawing which shows the outline of a structure of vehicle air conditioner AC to which Example 1 is applied. It is a side view which shows 2 A of double pipes of Example 2 of embodiment of this invention.

Explanation of symbols

1 Outer tube 1a Tip 1b Tip 2 Inner tube 2a Protrusion (stopper means)
2b Tip 2c Tip 4 Brazing material for inner pipe 5 Brazing material for outer pipe 11 Double pipe insertion hole 11a Opening 11b Outer pipe insertion part 12 Inner pipe insertion hole 13 Inner pipe communication path 14 Outer pipe communication path 15 Bottom wall 22 Inner tube 22a annular projection (stopper means)
A Double pipe 2A Double pipe B Double pipe fitting

Claims (3)

The inner pipe and outer pipe are coaxially arranged inside and outside double,
A tip portion of the inner tube protrudes from a tip of the outer tube;
A double pipe that is fused to a double pipe joint by melting a ring-shaped brazing material attached to the tip of the inner pipe and the tip of the outer pipe;
A double pipe characterized in that stopper means for restricting movement of the brazing material along the inner pipe in a direction away from the tip of the inner pipe is provided at the tip of the inner pipe. A double pipe insertion hole for inserting a double pipe, an inner pipe insertion hole which is opened in a bottom wall which is a contact portion of the double pipe insertion hole, and into which the tip of the inner pipe is inserted; An inner pipe communication passage formed continuously from the inner pipe insertion hole and communicated with an inner pipe flow path inside the inner pipe; and provided at an opening side end of the double pipe insertion hole. An outer tube insertion portion into which the outer tube is inserted when the distal end portion of the inner tube is inserted into the insertion hole, and an outer tube inside the outer tube formed continuously to the double tube insertion hole. A double pipe joint comprising an outer pipe communication path in communication with the flow path;
The double tube;
A combined structure of a double pipe and a double pipe joint,
In the state where the outer pipe is inserted into the outer pipe insertion portion of the double pipe insertion hole, it is brazed to the opening peripheral edge of the double pipe insertion hole,
In a state where the inner pipe is inserted into the inner pipe insertion hole, the inner pipe brazing material is melted between the opening peripheral edge of the inner pipe insertion hole and the stopper means, A combined structure of a double pipe and a double pipe joint, wherein the inner pipe is brazed. A method of brazing the double pipe and the double pipe joint,
Attaching a ring-shaped inner tube brazing material to the outer periphery of the distal end portion of the inner tube, and attaching a ring-shaped outer tube brazing material to the outer periphery of the distal end portion of the outer tube;
The double pipe is inserted into the double pipe insertion hole of the double pipe joint, and further, the inner pipe brazing material is abutted against the abutting wall and the stopper means and the tip of the inner pipe Insert the inner tube into the inner tube insertion hole until it is sandwiched between them, and insert the distal end of the outer tube into the outer tube insertion portion to place the outer tube brazing material outside the double tube insertion hole. A process of positioning the double pipe and both brazing materials in contact with the periphery;
Melting both brazing materials and brazing the double pipe to the double pipe joint;
A method of brazing a double pipe and a double pipe joint, characterized by comprising:

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