JPH115125A - Forming method for bulge with oil pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which the bulge forming can be carried out by a single process in which the bulge is formed by inserting the enforcing materials with adhesive agent to the exterior of the hollow materials making it possible that the adhesion of enforcing materials to the formed product and the bulge forming can be conducted simultaneously by a single process. SOLUTION: An exterior diameter of a reinforcing material 2 is made more or less smaller than the exterior diameter of a hollow material or of the interior diameter D of a female die 11, and plural of convex shaped peg portions 2a are arranged at the upper and lower ends so that it is made possible to form a larger space, thicker than the thickness of the adhesive agent applied in its inside between the hollow material 1a. And a closing hole 2b is set on the exterior side of the enforcing material 2 so as to be fixed to the female mold 11 by a positioning pin 13 when inserted into a forming apparatus 11. At the time of the forming, an adhesive agent 3 is applied inside the enforcing material 2 to be inserted into the fixed position at the exterior side of the hollow material 1a. Under this condition, (A) firmly positioned in the mold 11 and 12 by a position fixing hole 2b and the pin 13, after that (B) the high pressured liquid is taken into aforesaid material 1a and the adhesion and the forming are carried out at a time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic bulge forming method for expanding and plastically processing a pipe or the like by using a liquid pressure, and more particularly to a hydraulic bulge for joining another member to a bulge formed product simultaneously with bulge forming. The present invention relates to a composite molding method.

[0002]

2. Description of the Related Art A general hydraulic bulge forming method has been widely used for bicycle frames and pipe joints, and has attracted attention in the field of automobiles as a method of forming a hollow member having a good sectional space efficiency as a vehicle body structural member. Have been.

[0003] In particular, as a countermeasure against increasing the strength against side collision, it is studied to provide a hollow member obtained by a hydraulic bulge forming method on a front pillar, a center pillar, or the like as a member capable of increasing the strength without increasing the weight. Have been.

[0004] In order to partially increase the strength of this kind of hollow reinforcing member, another part 2 is joined to the hollow member 1 as shown in FIG. 4, for example. When manufacturing the one shown in the figure, first, the hollow bulge molded body 1 shown in FIG. 5B is produced using a general hydraulic bulge molding apparatus 10 shown in FIG. Another part 2 shown in FIG. 1C is joined to the recess 1 by welding or the like.

[0005] In Fig. 5A, "1a" is a hollow material (raw material) set in the molds 11 and 12, and when the high-pressure liquid L is injected into the hollow material 1a, the hollow material 1a is formed. Both ends of 1a bulge, and a bulge 1 conforming to the shape of the mold 11 is obtained.

[0006]

However, the conventional molding method has a fundamental problem that a step for welding and joining different parts is required separately from the bulge forming step. Further, according to the welding, in addition to the problem of thermal distortion, there is also a problem of welding spatter or interference between a welding bead and another component.

The present invention has been made in view of such problems of the prior art, and has as its object to provide a hydraulic bulge forming method capable of joining different parts to a bulge formed product in the same process. And

[0008]

According to a first aspect of the present invention, there is provided a hydraulic bulge forming method in which a member to be joined outside a hollow member is provided between the hollow member and the joining member. After the insertion with the adhesive applied, a liquid is injected into the hollow portion of the hollow member to form a bulge.

In the hydraulic bulge forming method according to the first aspect, first, a member to be joined to the outside of the hollow member is inserted in a state where an adhesive is applied between the hollow member and the joining member. This is set in a bulge mold, and a high-pressure liquid is injected into the hollow portion of the hollow member to perform bulge molding.

As a result, a predetermined bulge forming is achieved because the hydraulic pressure swelling outward acts on the hollow member.
The portion where the joining member is inserted on the outside also receives the expansion force. Since the hydraulic pressure always acts evenly on the inner surface of the hollow member, the hollow member is evenly pressed against the joining member, whereby the adhesive is spread evenly and uniform pressure bonding is performed. In other words, the secondary stretching of the adhesive and uniform pressure bonding are performed using the liquid pressure at the time of bulge molding.

In the hydraulic bulge forming method according to the first aspect, the adhesive may be applied to any of the hollow member and / or the joining member, and the clearance therebetween is not particularly limited. In the hydraulic bulge forming method, the adhesive may be applied to an inner surface of the joining member, and a clearance exceeding the applied thickness of the adhesive may be formed between the hollow member and the joining member. Features.

[0012] By securing a clearance exceeding the thickness of the adhesive applied, the adhesive can be prevented from contacting the surface of the hollow member unnecessarily, and the uniform spread of the adhesive according to claim 1 can be further ensured. Can be achieved.

According to a third aspect of the present invention, there is provided a hydraulic bulge forming method, wherein the joining member is positioned in a forming die during the bulge forming. In particular, by positioning the joining member in the molding die at one location, it is possible to eliminate the need for handling even if the shape of the other part is different.

[0014]

According to the hydraulic bulge forming method of the present invention,
Since the hollow member and the joining member are uniformly pressed in one bulge forming step, a separate joining step can be omitted.

Further, since the bonding is performed by using an adhesive, the problem of thermal distortion, the problem of interference between spatters and welding beads and other parts, and the like can be solved.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, as shown in FIG. 4, a reinforcing member (a joining member of the present invention) is provided in a concave portion of the hollow member 1.
The present invention will be described by taking as an example a case where a hollow composite member having an overall outer diameter of D is manufactured by joining the two to locally reinforce this portion.

First, as the hollow material 1a which is a raw material of the hollow member 1, a hollow member having an outer diameter smaller than D and having a uniform diameter is used. In the following, the hollow member 1a is referred to before molding and the hollow member 1 is referred to after molding.

As shown in FIG. 2, the reinforcing member 2 joined to the outside of the hollow member 1 has an outer diameter of substantially D, and has three protruding claw portions at upper and lower ends. 2a
Are formed.

As shown in FIG. 3, when the reinforcing member 2 is inserted into the hollow material 1a, the convex claw portion 2a is provided between the hollow material 1a and the reinforcing member 2 with an adhesive (described later). 3 is formed to a size that can ensure a clearance S larger than the coating thickness t. This is to prevent the adhesive 3 from contacting the hollow material 1a before performing the hydraulic bulge forming. Therefore, the shape and the number of the convex claws 2a are not limited only to the present embodiment unless deviating from the purpose.

A positioning hole 2b is formed on the side surface. The positioning hole 2b is a hole for fixing the reinforcing member 2 when the hollow material 1a into which the reinforcing member 2 is inserted is set in a hydraulic bulge forming apparatus 10 described below.
Here, the positioning pins 13 are inserted.

On the other hand, the hydraulic bulge forming apparatus 10 according to the present embodiment is a female mold 11 arranged around the hollow material 1a and having an inner surface shape corresponding to the outer shape of the intended hollow member 1.
And upper and lower molds 12 and 12 for closing the upper and lower openings of the hollow material 1a. The female mold 11 is provided with the positioning pins 13 described above.

The high-pressure liquid serving as a source of bulge molding is as follows:
It is supplied from a supply source (not shown) through one end opening of the hollow material 1a via the upper and lower molds 12.

Next, the operation will be described. First, an adhesive is applied to the inner surface of the reinforcing member 2 shown in FIG. 2, and the reinforcing member 2 is inserted outside the hollow material 1a. In this state, FIG.
As shown in (1), the reinforcing members 2 are fixed by inserting the positioning pins 13 into the positioning holes 2b of the reinforcing member 2 as shown in FIG. The hollow material 1a is held by the upper and lower dies 12, 12.

After being set as described above, the high-pressure liquid L is injected into the hollow material 1a. As a result, FIG.
As shown in (B), a hydraulic pressure swelling outward acts on the hollow material 1a, and as a result, a region other than the portion where the reinforcing member 2 is inserted is bulge-formed along the inner surface shape of the female mold 11. You.

At the same time, the portion where the reinforcing member 2 is inserted on the outside also receives the expansion force, but the hydraulic pressure always acts evenly on the inner surface of the hollow material 1a. The adhesive 3 is spread evenly and uniform pressure bonding is performed.

As described above, according to the hydraulic bulge forming method of the present embodiment, the joining of the reinforcing member 2 can be performed simultaneously with the bulge forming, so that the steps can be shortened and the cost can be reduced. Can be. Further, since the adhesive 3 is used, problems such as thermal distortion, spatter, and interference with a weld bead are solved.

The embodiments described above have been described in order to facilitate understanding of the present invention, but are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, the specific shape of the hollow material 1a, the hollow member 1, or the reinforcing member 2 is not particularly limited, and a shape other than the above-described embodiment can be applied.

The adhesive 3 may be applied to the outer surface of the hollow material 1, or may be applied to both the inner surface of the reinforcing member 2 and the outer surface of the hollow material 1a.

Further, the specific structure of the hydraulic bulge forming apparatus 10 is not particularly limited, and can be appropriately changed according to a target molded product. Also, the means for positioning the reinforcing member 2 is not limited to the combination of the hole 2b and the pin 13 at all, and other means can be used.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining an embodiment of a hydraulic bulge forming method according to the present invention.

FIG. 2 is a perspective view showing an embodiment of a joining member according to the hydraulic bulge forming method of the present invention.

FIG. 3 is an enlarged cross-sectional view for explaining a clearance between a hollow member and a joining member according to the hydraulic bulge forming method of the present invention.

FIG. 4 is a perspective view showing an embodiment of a molded product to be produced by the hydraulic bulge molding method of the present invention.

FIG. 5 is a cross-sectional view and a perspective view for explaining a conventional hydraulic bulge forming method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hollow member 1a ... Hollow material 2 ... Joining member 2a ... Convex claw part 2b ... Positioning hole 3 ... Adhesive 10 ... Hydraulic bulge forming apparatus 11 ... Female mold 12 ... Vertical mold 13 ... Positioning pin

Claims (3)

[Claims] A bulge is formed by inserting a member to be joined to the outside of a hollow member with an adhesive applied between the hollow member and the joining member, and then injecting a liquid into a hollow portion of the hollow member. A hydraulic bulge forming method characterized by forming. 2. The method according to claim 1, wherein the adhesive is applied to an inner surface of the joining member, and a clearance is formed between the hollow member and the joining member, the clearance exceeding an applied thickness of the adhesive. The hydraulic bulge forming method according to claim 1. 3. The hydraulic bulge forming method according to claim 1, wherein said joining member is positioned in a forming die during said bulge forming.