JP2003285128A - Forming method for hollow member and its end - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method for a hollow member and its end which is superior in design and also low in price by processing the end integrally with a middle part. <P>SOLUTION: The forming method is provided with a process, in which a hollow tube 16 having a concave part 5 in a shape of a fold where the surrounding wall is folded inward is formed from a metal material and a punch 19 is inserted into an end 16a of the hollow tube 16 for expanding the end 16a, and a process in succession, in which the shape of a cross-section of the end 16a is formed so that it becomes gradually smaller towards the end. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow member formed by gradually changing the end of a hollow tube extending in a constant cross-sectional shape and a method for forming the end.

[0002]

2. Description of the Related Art Conventionally, there has been known a method of molding a hollow member used for a roof rail of a vehicle by gradually changing its end portion by hydraulic pressure. For example, Japanese Patent Laid-Open No. 2001-158
In Japanese Patent Publication No. 304-304, an extruded material having a dovetail-shaped groove is bent and then inserted into a mold for molding an external shape, and a high pressure is applied to the inside of the extruded material using water as a pressure medium to form a rail portion which is an intermediate portion. A method for manufacturing a roof rail of a vehicle in which the leg portions at both ends are integrally formed is described.

[0003]

However, in the above-mentioned conventional technique, a device for applying a high pressure and a large-scale mold capable of inserting the entire hollow member are required, which leads to an increase in manufacturing cost. It was a thing. Further, since a high pressure is applied to the entire hollow member, there is a possibility that the mold may be hit and scratched over the entire hollow member.

Further, if the end portion of the hollow pipe is simply expanded by hydraulic pressure or a punch, the wall pressure of the expanded end portion may be partially thinned and the strength may be reduced.

Therefore, the present invention has been made in view of the above circumstances, and an end portion is integrally formed with an intermediate portion to be excellent in design and an inexpensive hollow member and an end portion forming method thereof. To provide the technical problem.

[0006]

In order to solve the above-mentioned technical problems, the present invention provides a hollow tube extending from a metal material in a constant cross-sectional shape having a recess as described in claim 1. Forming the hollow tube, inserting a punch into the end of the hollow tube to expand the end, and then forming the hollow so that the cross-sectional shape of the end gradually decreases toward the end. And a method for forming an end portion of a hollow member.

According to the method of molding the end of the hollow member according to the present invention, a general press machine can be used as equipment for inserting the punch into the end of the hollow tube to expand the end, and the manufacturing cost can be increased. You can suppress the rise of. In addition, since the end of the hollow tube that has a predetermined cross-sectional shape and has a recess is expanded and molded, the overall thickness can be made substantially constant, and the end can be molded. It is possible to prevent the strength from decreasing.

Preferably, as described in claim 2, it is desirable that the recess has a pleated shape in which the peripheral wall of the hollow tube is folded inward. According to this, it becomes possible to expand and shape the end portion of the hollow tube into a shape having a greater degree of freedom.

Further, according to the present invention, as described in claim 3, both ends are molded by the molding method according to claim 1 or 2, and the intermediate part has a constant cross-sectional shape having the recess. And a hollow member. In this way, by integrally molding both end portions of the hollow member with the intermediate portion,
It can be excellent in design. Furthermore, since the intermediate portion still has a certain cross-sectional shape having a concave portion, the concave portion functions as a rib and the strength can be improved.

Preferably, as described in claim 4, in the hollow member according to the present invention, both ends are attached to the roof of the vehicle, and the recess is preferably located on the roof side. In this way, since the concave portion can be located on the roof side, that is, at a position where it is difficult to see from the field of view, it can be applied to the roof rail of the vehicle.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 are views showing an embodiment of a hollow member according to the present invention. FIG. 1 is a side view, and FIGS.
2 is an enlarged cross-sectional view showing an AA cross section of FIG. 1,
BB cross section, CC cross section, and FIG. 5 are vertical cross-sectional views in which the leg portion (on the left side in FIG. 1) is enlarged.

The hollow member 1 in the present embodiment is used as a roof rail attached to a roof 4 of a vehicle, as shown in FIG. The roof rail (hollow member 1) is composed of a rail portion 3 that is an intermediate portion and two leg portions 2 that are both end portions.

As shown in FIG. 4, the roof rail 1 has a lower surface portion 7 of a leg portion 2 fixed to a roof 4 of a vehicle through a resin plate 13 by bolts 15 and nuts 14 which are fixing members. Actually two roof rails 1
Are provided on the left and right sides of the vehicle roof.

As shown in FIG. 2, the rail portion 3 has a hollow tubular shape extending in a constant cross-sectional shape having two recesses 5. The recess 5 is formed on the lower surface of the peripheral wall 8 of the rail portion 3 (see FIG.
(Downward in) is a fold shape that is folded inward. That is, in the roof rail 1 attached to the roof of the vehicle, the recess 5 is located on the roof side.

The leg portion 2 is smoothly gradually changed from the rail portion 3 and expanded to form a lower curved portion 17. Figure 3
As shown in FIG. 5, the recess 5 in the rail portion 3 is a recess 6 which is pushed from the inside and widened to have a shallow depth.
The concave portion 6 is gradually shallowed toward the end surface of the roof rail 1 in the lower curved portion 17, and the concave shape is eliminated in the lower surface portion 7 to form a flat surface as shown in FIG.

The hollow cross-sectional area of the roof rail 1 gradually increases as the depth of the recess 6 decreases. That is, the cross sectional area surrounded by the peripheral wall 9 in the BB cross section is larger than the hollow cross sectional area surrounded by the peripheral wall 8 in the AA cross section, and the cross sectional area surrounded by the peripheral wall 10 in the CC cross section is larger. ing. At this time, the peripheral lengths of the peripheral walls 8, 9, 10 in each cross section are substantially constant.

As shown in FIG. 2, the side surface 5a of the recess 5 is
It is parallel to the direction in which it is spread and the two recesses 5 have the same depth. As a result, it can be smoothly pushed out to form the concave portion 6 and the lower surface portion 7.

As shown in FIGS. 1 and 5, an upper curved portion 18 is formed on the upper surface of the peripheral wall of the leg portion 2 and is gradually bent toward the roof side toward the end surface of the roof rail 1. That is, the cross-sectional shape of the upper curved portion 18 of the leg portion 2 gradually decreases toward the end surface of the roof rail 1. Therefore, the hollow cross-sectional area of the leg portion 2 is larger at the lower curved portion 17 and smaller at the upper curved portion 18 toward the end surface of the roof rail 1.

The lower curved portion 17 and the upper curved portion 18 may overlap with each other in the vertical direction (vertical direction in FIG. 5). Further, in a top view of the roof rail 1 (as viewed from above in FIG. 1), the leg portion 2 has a shape that is wider than the rail portion 3.

Next, a method of manufacturing the roof rail (hollow member 1) shown in FIGS. 1 to 5 will be described with reference to FIGS. 6 to 9. 6 to 9 are vertical cross-sectional views showing a method for forming the left leg portion 2 in FIG.

First, by extruding a metal material (billet) of an aluminum alloy, as shown in FIG.
The hollow tube 16 which is a molding rough material is molded. The cross-sectional shape of the hollow tube 16 (cross section D-D in FIG. 6) is shown in FIG. 2 (A-A in FIG. 1).
It has the same shape as the cross section). That is, the hollow tube 16 is
It extends in a constant cross-sectional shape with two recesses 5.

After inserting the hollow tube 16 into the outer die 20, a punch 19 having a sharp tip and a curved portion 19a corresponding to the lower curved portion 17 is formed on the end portion 1 of the hollow tube 16.
When it is inserted into the hollow portion of 6a and pushed in (to the right in FIG. 7), the end portion 16a is expanded and the lower curved portion 1
7 and the lower surface portion 7 are molded into the state shown in FIG.

After pulling out the punch 19, as shown in FIG. 8, the lower surface 22 and the side surface 21 are cut off in a triangular shape (surrounded by the end surface of the end portion 16a and the lower surface 22). After that, FIG.
As shown in FIG. 5, the core 25 is inserted into the hollow portion of the end 16a, and the end 16 is fixed to the lower mold 24 and is bent by the roll forming jig 26 to form the upper bent portion 18. .

The other leg portion 2 (on the right side in FIG. 1)
Is similarly molded. At this time, equipment that can form the two leg portions 2 at both ends in the same manner may be adopted. Also,
By using punches 19 and cores 25 having different shapes, it is possible to make the both ends of the roof rail 1 different leg portions 2 having different shapes.

As described above, in the present invention, the equipment for inserting the punch 19 into the end portion 16a of the hollow tube 16 to expand the end portion can be a general press machine, which increases the manufacturing cost. Can be held down. Further, since the end portion of the hollow tube 16 having the predetermined cross-sectional shape and having the recess 5 is expanded and formed, the overall thickness can be made substantially constant, and the end portion can be formed. It is possible to prevent a decrease in strength due to a decrease in wall thickness. Furthermore, the recess 5
Has a fold shape in which the peripheral wall of the hollow tube 16 is folded inward, so that the end portion 16a of the hollow tube 16 can be expanded and shaped into a shape having a greater degree of freedom.

Further, according to the present invention, since the leg portions 2 at both ends are formed and the intermediate rail portion 3 is a roof rail (hollow member 1) having a constant cross-sectional shape with the recess 5, the both ends of the roof rail 1 are formed. By molding the leg portion 2 integrally with the rail portion 3, the leg portion 2 can be excellent in design. Furthermore, since the rail portion 3 still has a certain cross-sectional shape having the concave portion 5, the concave portion 5 functions as a rib and the strength can be improved. As described above, the hollow member according to the present invention can be applied to the roof rail 1 of the vehicle. At this time, the leg portion 2 is attached to the roof 4 of the vehicle, and the concave portion 5 is located on the roof 4 side. It is also possible to place the recess 5 on the roof 4 side, that is, at a position that is difficult to see from the field of view.

In the above-mentioned embodiment, the molding raw material is 2
Hollow tube 1 having a constant cross-sectional shape with one recess 5
Although the sixth example is shown, in implementing the present invention, the same effect as that of the above-described embodiment can be obtained even if the hollow tube has one recess or three or more recesses. That is, it is sufficient that a hollow tube is formed in accordance with the cross-sectional shape of the rail portion, and the hollow tube is provided with a recessed portion as an extra portion so that the hollow tube can be expanded and formed into the shape of the leg portion. Further, the hollow member according to the present invention constituted by the rail portion and the leg portions at both ends can be applied not only to the roof rail but also to a door grip attached to a back door of a vehicle and used when opening and closing. is there.

[0029]

As described above, according to the present invention,
Since the end portion can be integrally formed with the intermediate portion, it is possible to provide a hollow member that is excellent in design and is inexpensive, and a method for forming the end portion thereof.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a hollow member according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a sectional view taken along line CC of FIG.

5 is an enlarged vertical sectional view of a leg portion in FIG.

FIG. 6 is a vertical cross-sectional view showing a hollow tube which is a molding rough material.

FIG. 7 is a vertical cross-sectional view showing that the leg portion is being molded.

FIG. 8 is a vertical cross-sectional view showing that the leg portion is being formed.

FIG. 9 is a vertical cross-sectional view showing that the leg portion is being formed.

[Explanation of symbols]

1 Roof rail (hollow member) 2 legs 3 rails 4 roof 5 recess 7 Lower surface 16 hollow tubes 16a end 17 Under bend part 18 Upper curve part 19 punch 20 external type 25 core 26 roll forming jig

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60R 9/04 B60R 9/04

Claims (4)

[Claims] 1. A step of forming a hollow tube having a recess from a metal material, inserting a punch into the end of the hollow tube to expand the end, and thereafter, the cross-sectional shape of the end is an end surface. And a step of forming the hollow member so that the end portion of the hollow member is formed. 2. The recessed portion has a pleated shape in which a peripheral wall of the hollow tube is folded inward.
The method for forming an end portion of a hollow member according to [4]. 3. A hollow member characterized in that both ends are molded by the molding method according to claim 1 or 2, and the middle part has a constant cross-sectional shape having the recess. 4. The hollow member according to claim 3, wherein the both ends are attached to a roof of a vehicle, and the recess is located on the roof side.