JPH0952132A - Manufacture of metallic pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save space for a bending part in a metallic pipe joint without using a brazing means. SOLUTION: The method consists of a bending process, in which bending is done at proximity to the connecting end 12 of a metallic pipe 10 so that the inner radius RIN for bending may be roughly zero, and a fixing process in which a holding plate 11 is fixed between the connecting end 12 of the metallic pipe 10 and a bending part 13. With a first and a second annular recessed parts 15, 16 formed on both end faces of a pipe through-hole 14 and, with a part of the metallic pipe 10 expanded corresponding to the first and the second annular recessed parts 15, 16 to form a first and a second flanges 17, 18 in press-contact with these recessed parts 15, 16, the holding plate 11 is fixed on the metallic pipe 10 by means of the first and the second flanges 17, 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal pipe joint, and can be effectively used as a method for manufacturing a joint such as a refrigerant pipe in an automobile air conditioning system.

[0002]

2. Description of the Related Art In a refrigerant pipe in an air conditioning system for an automobile, a metal pipe joint as shown in FIG. 5 is used from the viewpoint of saving space in a bent portion of a refrigerant passage. In FIG. 5, 1 is a fixed block and 2 is a metal pipe made of aluminum. Fixed block 1 has L
The fixed block 1 is formed with a V-shaped passage 3.
Is formed with a bolt hole 4 for fixing it to another member (not shown). The connection end 2a of the metal pipe 2 is received by the one end 3a of the passage 3 of the fixed block 1 and brazed by the brazing material 5.

[0003]

According to the above-mentioned prior art, since the metal pipe 2 is brazed to the fixed block 1, the brazing may be caused by pinholes in the brazing material 5 or incomplete brazing due to wax breakage. There is a possibility that a leak may occur, or an excessive brazing flow may block the open surface of the connection end 2a of the metal pipe 2a.

The present invention has been made based on the above viewpoint, and an object thereof is to provide a method for manufacturing a metal pipe joint which can save space in a bent portion without using brazing means. .

[0005]

According to the present invention, a metal pipe connected to another conduit member is bent in the vicinity of the connection end so that the inner radius of the bend is approximately 0, and the connection end of the metal pipe is bent. And a bending step of forming a bent portion in the vicinity of the portion, and a connecting end portion of the metal pipe is inserted through a pipe through hole formed in a holding plate for holding the metal pipe so that the holding plate is attached to the metal pipe. In the fixing step of fixing between the bent portion and the connection end portion, first and second annular concave portions having a diameter larger than that of the pipe through hole are formed on both end surfaces of the pipe through hole of the holding plate, The diameter of the portion of the metal pipe corresponding to the first and second annular recesses is expanded to form first and second flange portions that are in pressure contact with the first and second annular recesses of the holding plate. 1 and 2 By the manufacturing method of the metal pipe fitting having said fixing step for clamping fixing the holding plate to the metal pipe by flange portion, to achieve the above object.

In the bending step, prior to the bending of the metal pipe by the bending die and the tightening die, the diameter of the metal pipe is slightly smaller than the outer diameter of the metal pipe formed by the pressure die and the wiper die. Through the pipe insertion hole of
The metal pipe may be configured to be bent by the bending die and the fastening die so that the inner radius of the bending is substantially 0 in a state where the outer diameter of the metal pipe is narrowed and plastically deformed. Furthermore, in addition to this, the pressure die is moved in the axial direction of the metal pipe toward the bent portion of the metal pipe in response to the bending of the metal pipe, and during the bending of the metal pipe, the metal It can be configured to exert an axial compressive force on the pipe.

[0007]

1 is a sectional view showing an example of a metal pipe joint manufactured by the method of the present invention, and FIG. 2 is a plan view of the structure of FIG.

In FIGS. 1 and 2, 10 is a metal pipe such as aluminum, and 11 is a holding plate fixed to the metal pipe 10. The metal pipe 10 has a bent portion 13 near the connection end 12 that is bent in an L-shape so that the inner radius R _{IN of} bending becomes substantially zero. Holding plate 11
Has a pipe through hole 14, and first and second annular recesses 15 and 16 having a diameter larger than that of the pipe through hole 14 are formed on both end surfaces of the pipe through hole 14 coaxially with the pipe through hole 14. In the metal pipe 10, the connecting end 12 has the holding plate 1
The first and second flange portions 17 are inserted into the pipe through holes 14 so as to protrude through the pipe 1 and are formed in portions corresponding to the first and second annular recesses 15 and 16 of the holding plate 11. , 18 hold the holding plate 11 in between. The holding plate 11 is a metal pipe 1.
It is fixed between the connection end 12 of 0 and the bent portion 13. In this example, the connection end 12 of the metal pipe 10 is slightly larger in diameter than the outer diameter of the metal pipe 10 so that a conduit member (not shown) is connected for communication. The holding plate 11 is further formed with a bolt hole 19 for fixing to another member (not shown).

In such a metal pipe joint, the metal pipe 10 is bent so that the inner radius R _IN of the bending becomes approximately 0 in the bending process described below, and then the holding plate 11 is attached to the metal pipe 10 in the fixing process. It is clamped and fixed.

3 and 4 are sectional structural views showing the bending process of the metal pipe 10. FIG. 3 shows a state before bending,
FIG. 4 shows the state after bending.

In FIGS. 3 and 4, 20 is a bending die,
Reference numeral 21 is a tightening die, 22 is a pressure die, and 23 is a wiper die.
The holding surfaces 20a, 21a of the bending die 20 and the tightening die 21 have a groove shape having a semicircular cross section, and the outer circumference of the metal pipe 10 is covered by the holding surfaces 20a, 21a. The fastening die 21 is movable in the vertical direction in the drawing, and by moving it toward the bending die 20, the metal pipe 10 is sandwiched between the bending die 20 and the fastening die 21. The bending die 20 and the fastening die 21 are driven to rotate downward about a bending center C. The bending die 20 has a substantially wedge shape on the side of the bending center C, and its tip is formed to have a curved surface with an extremely small radius, for example, an extremely small radius of about 0.5 mm. The pressure die 22 is on the side of the clamping die 21,
The wiper molds 23 are arranged on the bending mold 20 side, respectively.
The pressure surface 22a of the pressure die 22 and the wiper surface 23a of the wiper die 23 are grooves having a semicircular cross section, and are formed by the pressure die 22 and the wiper die 2
The pipe insertion hole 24 having a circular cross section is formed by combining these with the pipe 3. The inner diameter of the pipe insertion hole 24 is slightly smaller than the outer diameter of the metal pipe 10.
When 0 is passed therethrough, the outer diameter is narrowed and plastic deformation occurs. The inner diameter of the pipe insertion hole 24 is
Preferably, the diameter is smaller than the outer diameter of the metal pipe 10 by about 1 to 4%. One end of the pipe insertion hole 24 is open to the bending center C side, and the opposite side is a side opposite to the bending center C via a taper hole 25 and a guide hole 26 having a larger diameter than the pipe insertion hole 24. It is open to. The pressure die 22 and the wiper die 23 that form such a pipe insertion hole 24 are provided on a fixed mount 27. The pressure die 22 is engaged with the sliding groove 28 of the mounting base 27, is slidable in the axial direction of the metal pipe 10, and has the first hydraulic device 29.
It is designed to be moved by. The wiper mold 23 is fixed to the mount 27 with bolts 30 and 31.
Reference numeral 32 is an extruded member, which has a pipe portion 32a having substantially the same outer diameter and inner diameter as the metal pipe 10 and the second hydraulic device 3.
3 has a pressure receiving portion 32b that receives hydraulic pressure. The extruding member 32 is configured such that the pipe portion 32a thereof is inserted into the pipe insertion hole 24 and the rear end of the metal pipe 10 can be pushed by the hydraulic pressure of the second hydraulic device 33. Reference numeral 34 is a cored bar, which penetrates the extruding member 32 and is inserted up to a portion corresponding to the bending center C in the metal pipe 10. The tip of the cored bar 34 is formed into a curved surface so that the surface of the tip comes into contact with the outer inner wall of the metal pipe 10 when the metal pipe 10 is bent as shown in FIG.

With such a structure, first, the metal pipe 10
Is pressed by the pushing member 32 at the rear end,
2 and a wiper mold 23, and the pipe is passed through a pipe insertion hole 24, and the outer diameter thereof is reduced and plastically deformed, and then delivered to the bending mold 20 and tightening mold 21 sides. By feeding the metal pipe 10 for a predetermined length, the clamping die 21 is moved toward the bending die 20, and the metal pipe 10 in the plastically deformed state is sandwiched between the bending die 20 and the clamping die 21. Then, the pushing member 3 is moved by the second hydraulic device 33.
An axial compressive force is applied to the metal pipe 10 via 2 and, in this state, as shown in FIG.
1 is rotated downward about the bending center C, and the pressure die 22 is moved in the axial direction toward the bent portion of the metal pipe 10 in accordance with the rotation of the bending die 20 and the clamping die 21. Since the metal pipe 10 is bent by the substantially wedge-shaped bending die 20 in a plastically deformed state, the metal pipe 10 is bent in an L-shape so that the inner radius R _{IN of} bending becomes substantially zero. In addition, since the compressive force in the axial direction is applied to the metal pipe 10 during the bending and the pressure die 22 is moved according to the bending, it is possible to prevent the wall pressure on the outside of the bending of the metal pipe 10 from decreasing. When the bending of the metal pipe 10 is completed, the tightening die 21 is separated from the bending die 20, and the metal pipe 10 is extruded to complete the bending process.

In the fixing step, first, first and second annular recesses having a larger diameter than the pipe through hole 14 are formed on both end faces of the pipe through hole 14 of the holding plate 11 in which the pipe through hole 14 and the bolt hole 19 are formed. 15 and 16 are formed, and the connecting end portion 12 of the metal pipe 10 is inserted through the pipe through hole 14. Next, the diameter of the portion of the metal pipe 10 corresponding to the first and second annular recesses 15 and 16 of the holding plate 11 is expanded to increase the diameter of the first and second annular recesses 15 and 15 of the holding plate 11.
First and second flange portions 17 and 18 that are pressed against 16 are formed, and the first and second flange portions 1 of the metal pipe 10 are formed.
The holding plate 11 is clamped and fixed to the metal pipe 10 by 7, 18. Since the inner bending radius R _IN of the metal pipe 10 is substantially 0 and is bent into an L-shape, the distance H between the metal pipe 10 and the holding plate 11 can be reduced, and the space for the bent portion can be saved. Can be achieved. Further, since the brazing means is not used, there is no risk of leakage due to pinholes or wax breakage, or passage blockage due to excessive brazing flow.

Although the fixing step is performed after the bending step in the above example, the present invention is not limited to this.

[0015]

As described above, according to the present invention, a bending step is performed in the vicinity of the connecting end portion of the metal pipe so that the inner radius of the bending is approximately 0, and both end surfaces of the pipe through hole of the holding plate are provided. The first and second annular recesses having a diameter larger than that of the pipe through hole are formed, and a portion of the metal pipe corresponding to the first and second annular recesses is expanded in diameter to be pressed against the first and second annular recesses. And the second flange portion is formed and the holding plate is sandwiched and fixed to the metal pipe by the first and second flange portions of the metal pipe. A method for manufacturing a metal pipe joint that can save space can be provided, and there is no risk of leakage due to pinholes, broken brazing, or the like, or passage blockage due to excessive brazing flow.

Further, in the bending step, the outer diameter of the metal pipe is drawn and plastically deformed prior to the bending of the metal pipe by the bending die and the clamping die, and the metal pipe is bent under this condition. The metal pipe can be easily bent so as to be substantially zero. Furthermore, since the compressive force in the axial direction is applied to the metal pipe during the bending and the pressure die is moved according to the bending, it is possible to prevent the wall pressure on the outside of the bending of the metal pipe from decreasing.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a metal pipe joint manufactured by the method of the present invention.

FIG. 2 is a plan view of the configuration of FIG. 1 viewed from the direction of arrow A.

FIG. 3 is a cross-sectional configuration diagram showing a bending process of a metal pipe, showing a state before bending.

FIG. 4 is a cross-sectional configuration diagram showing a bending step of the metal pipe, showing a state after bending.

FIG. 5 is a cross-sectional view showing a conventional example of a metal pipe joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Metal pipe 11 Holding plate 12 Connection end part 13 Bending part 14 Pipe through hole 15 1st annular recessed part 16 2nd annular recessed part 17 1st flange part 18 2nd flange part 20 Bending type 21 Tightening type 22 Pressure type 23 Wiper type 24 Pipe insertion hole

Claims (3)

[Claims] 1. A bend for bending a portion near a connecting end portion of a metal pipe connected to another conduit member so that an inner radius of the bending is substantially 0, and forming a bent portion near the connecting end portion of the metal pipe. A step of inserting the connecting end of the metal pipe into a pipe through hole formed in a holding plate for holding the metal pipe, and holding the holding plate between the bent portion and the connecting end of the metal pipe. In the fixing step, the first and second annular recesses having a diameter larger than that of the pipe through hole are formed on both end surfaces of the pipe through hole of the holding plate, which corresponds to the first and second annular recesses. Forming a first and a second flange portion that press-contacts the first and second annular recesses of the holding plate by enlarging the diameter of the portion of the metal pipe to be held, and holding the first and second flange portions of the metal pipe by the first and second flange portions. play The fixing step in the method of manufacturing the metal pipe coupling having a sandwiching fixed to the metal pipe. 2. In the bending step, prior to bending of the metal pipe by a bending die and a clamping die, the metal pipe is slightly smaller than the outer diameter of the metal pipe formed by a pressure die and a wiper die. Through a small diameter pipe insertion hole,
2. The metal pipe is bent by the bending die and the clamping die so that the inner radius of the bending becomes substantially 0 under the condition that the outer diameter of the metal pipe is narrowed and plastically deformed. Of manufacturing metal pipe fittings of. 3. In the bending step, the pressure die is moved in the axial direction of the metal pipe toward the bent portion of the metal pipe in accordance with the bending of the metal pipe, and during the bending of the metal pipe. The method for manufacturing a metal pipe joint according to claim 2, wherein an axial compressive force is applied to the metal pipe.