JP2003311329A - Die, method, and product for pressing winding cross section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight and highly rigid winding cross section pressed body having a twist portion in a middle of a closed sectional shape out of a stock at a low cost. <P>SOLUTION: One side surface We of a stock forming a twist portion is formed in a final shape, and the final shape is restricted by forming surfaces 8b<SB>1</SB>of dies 8 and 9 for combined bending to prevent the final shape of one side surface We of the stock from being deformed. The other side surface Wf forming the twist portion by the dies 8 and 9 for combined bending is bent. Open ends Wa of the twist portion are set together, and at the same time, and open ends Wa of a general portion are set together by bending side surfaces Wg and Wh forming general portions of the stock. Both the general portion and the twist portion restrict the stock shape by forming surfaces 8a<SB>1</SB>, 9a<SB>2</SB>, 9a<SB>3</SB>, 8b<SB>1</SB>, 9b<SB>3</SB>, and 9b<SB>4</SB>of the dies 8 and 9 for combined bending, and the general portion and the twist portion of desired shapes can be formed thereby. <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 technique for obtaining a product having a twist in the middle of a closed cross section as a press-formed product.

[0002]

2. Description of the Related Art An arm-shaped press-formed product having a closed cross-sectional shape is formed from a single material, that is, a so-called wound cross-section arm is lightweight and easily obtains high rigidity.
It is used for torsion beams of automobile suspensions. However, when it is necessary to form a twisted portion in the arm-shaped press-formed product, the twisted portion forms a negative angle with respect to the opening / closing direction of the press die,
Conventionally, as shown in FIG. 9, a general portion 1a and a twisted portion 1
The press-formed product 1 having b and the press-formed product 2 having the general portion 2a and the twisted portion 2b are separately press-formed, and the two press-formed products 1 and 2 are welded to each other by facing each other, thereby twisting. A method of manufacturing an arm-shaped press-formed product having a section was adopted.

[0003]

However, when the two press-formed products 1 and 2 are combined and welded, two welding lines are formed on the arm having the length L, so that the total welding length becomes 2L and the welding cost is high. And an increase in product weight due to two weld beads remaining on the product. In addition, the twisted portion 1 of the two press-formed products 1 and 2
As shown in FIG. 8 (b), b and 2b are restricted in their cross-sectional shapes in order to prevent a negative angle with respect to the press direction P at the time of each press molding, and to obtain a necessary product strength. In some cases, the cross-sectional shape deviates from the ideal cross-sectional shape. On the other hand, if an existing technique is used to form a winding cross-section arm without twisting and then a part of the arm is twisted to form an arm-shaped press-formed product having a twisted portion, the above-mentioned The problem caused by combining the two press-formed products 1 and 2 does not occur, but instead, it is difficult to maintain a predetermined closed cross-sectional shape in the twisting process, which may impair the stabilization of product quality. there were.

The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to obtain a press-formed product having a twist in the middle of a closed cross-sectional shape from a single material. It is to provide a lightweight, high-rigidity, high-quality wound-section press-formed product having a twisted portion at low cost.

[0005]

In order to solve the above-mentioned problems, a die for winding section press according to claim 1 of the present invention comprises:
A bending mold for bending a flat surface portion of a material to form a curved cross-sectional shape having a closed end and an open end, and an open end of a material having the curved cross-sectional shape are combined, and a general portion and a twist to the general portion are twisted. A die for winding cross-section pressing, including a die for forming a combined bending forming a closed cross-sectional shape having a portion, wherein the bending die has one side surface of the material to be the twisted portion formed into a final shape. The mold for forming the combined bending has a molding surface for restraining one side surface of the twisted portion having the final shape, and the other side surface serving as the twisted portion is bent to match the open end of the twisted portion. At the same time, a side surface of the material, which becomes the general portion, is bent, and a molding surface for aligning the open ends of the general portion is provided.

According to the present invention, one side surface of the material to be the twisted portion is molded into a final shape by the molding surface of the bending molding mold, and the final shape is molded into the combined bending molding mold. The restraint by the surface prevents one side surface of the material, which is already formed into the final shape and serves as the twisted portion, from collapsing the final shape during the joint bending process. And
For both the general portion and the twisted portion, the material shape is constrained by the molding surface of the mate-and-bend molding die, and the other side that serves as the twisted portion is bent to match the open ends of the twisted portions and at the same time By bending the side surface to be the general portion and aligning the open ends of the general portion, the general portion and the twisted portion having a desired shape can be formed.

A die for winding section pressing according to a second aspect of the present invention is the die for winding section pressing according to the first aspect, wherein the lap bending forming die has the twisted portion having the final shape. Has a molding surface for restraining one side surface of the fixed mold, and bends the other side surface to be the twisted portion to align the open end of the twisted portion, and at the same time, bends the side surface to be the general portion of the raw material Of the movable mold.

According to the present invention, at the time of the bending process, the one side surface of the twisted portion having the final shape is constrained by the molding surface provided on the fixed die, so that the entire bending process is performed. The one side surface of the twisted portion is brought into close contact with the molding surface of the fixed mold to surely prevent the final shape from being destroyed.
Further, only by bringing the movable die close to the fixed die, the material shape is constrained by the forming surface of the bending die, and the other side serving as the twisted portion is bent to align the open end of the twisted portion. At the same time, it is possible to bend the side surface of the raw material to be the general portion and align the open ends of the general portion to form the general portion and the twisted portion having a desired shape.

A die for winding section pressing according to a third aspect of the present invention is the die for winding section pressing according to the second aspect, wherein a molding surface of the movable die for forming a twisted portion by bending is formed. For guiding the other side surface of the twisted portion to one side surface of the twisted portion which has the same surface shape as the shaping surface of the general portion for the joint bending and which is continuous with the shaping portion and which has the final shape. And a surface-shaped portion.

According to the present invention, since the forming surface of the movable die for the joint bending forming of the twisted portion has a portion having the same surface shape as the forming surface of the general portion for the joint bending forming, At the time of bending, the joint bending of both the twisted portion and the general portion is started at the same timing, and unnecessary surface strain or the like occurs between the portion that becomes the twisted portion and the portion that becomes the general portion. Can be prevented. Further, with respect to the other side surface of the twisted portion, the surface shape that is continuous with a portion having the same surface shape as the molding surface of the general portion for the combined bending molding allows the one side surface of the twisted portion having the final shape to be formed. By guiding the other side surface of the twisted portion, the general portion and the twisted portion having a desired shape can be formed.

Further, in order to solve the above-mentioned problems, a winding section pressing method according to a fourth aspect of the present invention is a bending step of bending a flat surface portion of a material to form a curved sectional shape having a closed end and an open end. And a bending step of combining the open ends of the materials having the curved cross-sectional shape to form a closed cross-sectional shape having a general portion and a twisted portion with respect to the general portion,
In the bending step, one side surface to be the twisted portion of the material is formed into a final shape, and the shape of one side surface of the twisted portion forming the final shape is formed into the final shape in the bending step. While maintaining it, bend the other side that will be the twisted part and match the open end of the twisted part at the same time,
It is characterized in that the side surface of the material, which becomes the general portion, is bent so that the open ends of the general portion are aligned.

According to the present invention, in the bending step, one side surface of the material to be the twisted portion is formed into a final shape, and the final shape is maintained in the bending step, so that the bending step can be performed during the bending step. It is possible to prevent one side surface of the material, which has already been formed into the final shape and serves as the twisted portion, from collapsing the final shape. Then, by bending the other side of the twisted portion to match the open end of the twisted portion, and simultaneously bending the side surface of the raw material that becomes the general portion and aligning the open ends of the general portions, a general portion having a desired shape can be obtained. And the twisted portion can be molded.

A winding cross-section press-formed product according to claim 5 of the present invention for solving the above-mentioned problems is a press-formed product formed by the winding cross-section pressing method according to claim 4. According to the present invention, it is possible to obtain a press-molded product having a closed cross-sectional shape, which is molded from a single material and has the general portion and the twisted portion.

[0014]

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

FIG. 1 shows a side view of a winding cross section arm 3 which is a winding cross section press-formed product according to an embodiment of the present invention. Further, FIG. 2A shows a sectional view taken along the line AA of FIG. 1, and FIG. 2B shows a sectional view taken along the line BB of FIG. Winding section arm 3
Is a closed cross-section molded from a single material,
A twisted portion 3b is formed from the AA cross section which is the general portion 3a to the BB cross section. Here, a method of molding the winding cross section arm 3 will be described below together with the structure of the mold for molding the winding cross section arm 3.

FIGS. 3 to 7 show a general portion (A-A cross-sectional shape) and a twisted portion (B- of the winding cross-section arm 3 shown in FIG.
The sectional view shows the state of the mold and the material in each bending step for forming the (B sectional shape). Also, FIG.
FIG. 7A shows the mold and material of the portion taken along the line AA, and FIG. 7B shows the mold and material of the portion taken along the line BB. First, as shown in FIGS. 3A and 3B, end bent portions Wa are formed on both ends of the material W. The end portion bending molds 4 and 5 used in this step (end portion bending step) include a portion for forming a general portion shown in FIG. 3 (a) and a portion for forming a twisted portion shown in FIG. 3 (b). The molding surface has the same shape as the portion related to. Therefore, in the end portion bending process, the shape of the material W is the same for the portion taken along the line AA and the portion taken along the line BB of the mold.

Then, as shown in FIG. 4, the plane of the material W is
Bay with a closed end Wc and an open end Wd
Form a curved cross-sectional shape. In this process (folding process)
The bending molds 6 and 7 used are shown in FIG.
The molding surfaces 6a, 7a of the part related to the molding of the general part shown, and the figure
Molding surface 6 of the portion relating to the molding of the twisted portion shown in FIG.
b ₁, 7b₁, 6b₂, 7b₂And the shape of the molding surface is different
ing. And, in particular, the molding surface 6b₁, 7b₁Is the twisted part
One side We of the material to be the final shape (length, width, slope
It has a surface shape for forming into an angle. In addition,
At this point, only one side surface We of the material to be twisted is
Since it is molded into the final shape, one side W of the material that becomes the twisted part
The shapes of e and the other side surface Wf are different. Well
Also, regarding the other side surface Wf, in order to form a twisted portion,
Material width is required to bend parallel to one side We
Therefore, the molding surface 6b₂, 7b₂Is on one side We
In comparison, it has a surface shape for increasing the width of the other side surface Wf.
ing. On the other hand, a side surface W which is a general part shown in FIG.
g and Wh do not form a twist
Therefore, the width may be the same, so that
The molding surfaces 6a and 7a have the same shape.

Subsequently, as shown in FIGS. 5 to 7, the open end Wd of the material W having a curved cross-sectional shape is put together, and as shown in FIG.
A closed cross-sectional shape having a general portion 3a shown in (a) and a twisted portion 3b shown in FIG. 2 (b) is formed. Metal molds 8 and 9 for forming and bending for use in such a process (bonding and bending process)
As shown in FIGS. 5 (a) and 5 (b), the shapes of the molding surfaces of the general part and the twisted part are greatly different. First, as shown in FIG. 5 (b), the fixed die 8 of the fitting bending die is provided with a forming surface 8 b ₁ that restrains one side surface We of the twisted portion having the final shape. The molding surface 8b ₁ restricts only the closed end Wc that connects the side surfaces Wg and Wh that are the general parts, as shown in FIG.
The molding surface is continuous with the molding surface 8a ₁ .

On the other hand, the movable die 9 of the die for forming the combined bending is
As shown in FIG. 5 (b), the other side surface Wf to be the twisted portion is
Further bending the bending step of FIG. 4, twisted portion forming surface 9b ₁ ~ for adjusting the open end Wd (end bent portion Wa) of
It has 9b _4. Of such molding surfaces, the molding surface 9b ₁
Is a portion having the same surface shape as the molding surface 9a ₁ related to the joint bending of the general portion shown in FIG. 5 (a). And
Molding surface 9b ₁ is a ridge 9b ₂ as a boundary, the other side surface Wf of the twisted portion to the one side surface We of the twisted portion forming the final shape to guide, the molding surface 9b ₃ for molding the other side surface Wf to product shape It is continuous. Further, molding surface 9b ₃ continues with a top molding surface 9b _4, the top forming surface 9b ₄ for constraining the state where combined open end Wd of twisted portion (end bend Wa), the guide surface 9
It continues to b ₅ . The guide surface 9b ₅ does not directly contact the material W, and the guide surface 8b of the fixed die 8
It is the surface that closely contacts ₃ . In addition, the guide surface 8b ₂ of the fixed die 8
Is a surface that is in direct contact with the material W and is in close contact with the molding surface 9b ₁ of the movable mold 9.

The molding surface 9 of the general part shown in FIG.
a ₁ is a molding surface 9 for constraining the side surfaces Wg and Wh to the product shape.
continuously to a _2, further two molding surface 9a ₂ is continuous with the top molding surface 9a ₃ for constraining the state open end the combined Wd (end bent portion Wa) of the general portion. The guide surface 8a ₂ of the fixed die 8 is a surface that is in direct contact with the material W and is in close contact with the molding surface 9a ₁ of the movable die 9.

In the lap bending process using the lap bending molds 8 and 9, first, as shown in FIGS. 5 (a) and 5 (b), the molding surfaces 8a ₁ and 8b ₁ of the fixed mold 8 are formed. , The closed surface Wc of the portion that becomes the general portion and the portion that becomes the twisted portion is placed. At this time, as shown in FIG.
By restraining the one side surface We of the portion to be the twisted portion by ₁ , it is possible to surely prevent the one side surface We already formed in the final shape from collapsing the final shape. When the movable die 9 is approached toward the fixed die 8 from such a state, the end bent portions Wa of the side surfaces Wg and Wh which are in close contact with the molding surface 9a ₁ of the movable die 9.
(FIG. 5 (a)) and the end bent portion Wa (FIG. 5 (b)) of the other side surface Wf that is in close contact with the molding surface 9b ₁ of the movable die 9 are pressed as the movable die 9 approaches, Side Wg which is the general part,
Both the Wh and the other side surface Wf of the material to be the twisted portion can be jointly bent at the same timing.

Then, the molding surface 9a shown in FIG.₁To
The contact position of the end bent portion Wa of the opposite side surfaces Wg, Wh is
Forming surface 9a₁By moving to the upper end of side W
The end bent portions Wa of g and Wh are in close contact with each other.
Therefore, the open end Wd of the general portion is completely closed. further,
As shown in FIG. 6A, the side surfaces Wg and Wh, which are general parts, are as shown in FIG.
The molding surface 9a₂To the finished state parallel to each other.
I will be restrained. On the other hand, during the period from FIG. 5 to FIG.
Is the molding surface 9b₁End of other side Wf with respect to
As shown in Fig. 6 (b), the contact position of the bent part Wa is
Shape 9b ₁By moving to the upper end of the
The other side surface Wf of the part to be attached has the same degree of progress as the side surface Wh of the general part.
Then, the joint bending process proceeds. Therefore, FIG.
At the time of, the end portion of one side surface We of the material to be twisted is bent
The portion Wa and the bent end portion Wa of the other side surface Wf are in close contact with each other.
Not in.

From the state shown in FIG. 6, when the movable die 9 is further approached toward the fixed die 8, the side faces Wg and Wh of the general portion are constrained by the forming faces 9a _{2 in} a completed state parallel to each other, The contact position of the end bent portion Wa of the other side surface Wf, which serves as the twisted portion, with the movable die 9 moves to the molding surface 9b ₃ to further advance the combined bending. And FIG.
As shown in (a) and (b), when the movable die 9 is in close contact with the fixed die 8 (die clamping state), one side surface We of the twisted portion is shown.
The end bent portion Wa of the other side surface Wf and the end bent portion Wa of the other side surface Wf are in close contact with each other (FIG. 7B), and the open end Wd of the twisted portion is completely closed. Further, in this mold clamped state, all surfaces of both the general portion and the twisted portion are constrained by the molding surfaces 8a ₁ , 9a ₂ , 9a ₃ and 8b ₁ , 9b ₃ , 9b _{4 of the} fixed die 8 and the movable die 9. By being pressurized, the spring back is removed.

Then, by welding the closed open end Wd of the winding cross-section arm 3 formed from a single material by the above procedure, a finished product of the winding cross-section arm 3 can be obtained.

The operational effects obtained by the embodiment of the present invention having the above structure are as follows. That is, as shown in FIG. 4B, one side surface We of the material to be the twisted portion is formed into a final shape by the forming surfaces 6b ₁ and 7b ₁ of the bending forming dies 6 and 7, and the final shape is As shown in FIGS. 5 to 7, the molding surface 8 of the molds 8 and 9 for the combined bending molding.
By restraining it by b ₁ , it is possible to prevent the one side surface We of the material already formed into the final shape from collapsing the final shape during the lap bending process. Then, the other side surface Wf, which is a twisted portion, is bent by the matching bending molds 8 and 9 to match the open end Wa of the twisted portion, and at the same time, the side surfaces Wg, Wh, which are the general portion of the material, are bent to open the general portion. By aligning the ends Wa, the material shape of the general portion and the twisted portion can be changed by the respective molding surfaces 8a ₁ , 9a ₂ , 9a ₃ and 8b ₁ , 9b ₃ , 9b _{4 of} the matching bending molds 8, 9. It can be constrained to form general and twisted sections of desired shape.

Since the fixed bending molds 8 and 9 have the molding surface 8b ₁ for constraining the one side surface We of the twisted portion forming the final shape, the combined bending molding dies 8 and 9 have already been formed into the final shape. It is possible to reliably prevent the one side surface We of the material to be the twisted portion from being brought into close contact with the molding surface 8b ₁ and breaking the final shape thereof during the entire bending process. In addition, the other side surface Wf serving as the twisted portion is bent to align the open end Wd of the twisted portion with the movable die 9, and at the same time, the side surfaces Wg and Wh serving as the general portion of the material are bent to align the open end Wa of the general portion. Since the molding surfaces 9b ₁ , 9b ₃ and 9a ₁ , 9a ₂ are provided, only the movable die 9 is brought close to the fixed die 8 and the general portion and the twisted portion are bent without using a movable insert. It can be performed.

Further, the movable mold 8, the molding surface 9b ₁ according to the combined bending the twisted portion, 9b ₃ is a partial 9b ₁ forming the same surface shape and the molding surface 9a ₁ of the mating of the general portion bending Therefore, when the bending process is performed, the movable die is moved closer to the start of the bending process for both the twisting portion and the general portion at the same timing, so that the twisting portion of the material W is formed. It is possible to prevent unnecessary surface strain and the like from being generated between the general portion and the portion. Further, with respect to the other side surface Wf of the twisted portion, the twisted portion having the final shape is formed by the shaping surface 9b ₃ which is continuous with the portion 9b ₁ having the same surface shape as the shaping surface 9a ₁ for the general bending and shaping. One side W
By guiding the other side surface Wf of the twisted portion to e, a general portion and a twisted portion having a desired shape can be formed.

Therefore, the winding cross-section arm 3 having the closed cross-section shape having the general portion 3a and the twisted portion 3b can be formed from a single material without difficulty. The winding cross-section arm 3 obtained according to the embodiment of the present invention is completed as a product by welding the closed open end Wd, and the welding line remaining in the product becomes one, thereby increasing the product weight. It is possible to prevent it and reduce the manufacturing cost.

Further, all of the end bending molds 4, 5, the bending molds 6, 7, and the combined bending molds 8, 9 may form a negative angle with respect to the pressing direction. Therefore, the winding cross-section arm 3 can have an ideal cross-sectional shape for obtaining a desired product strength. In FIG. 8A, the welding counterpart component 10 of the winding cross-section arm 3 is three-dimensionally shown, and the welding surface of the twisted portion 3b of the winding cross-section arm that closely adheres to the welding counterpart component 10 is indicated by the hatched portion. There is. For reference, the welding surfaces of the twisted portions 1b and 2b of the arm formed by combining the two conventional press-formed products 1 and 2 together with the welding counterpart 10 shown in FIG.
Is indicated by the shaded area. As is apparent from FIG. 8, the winding cross-section arm according to the embodiment of the present invention (FIG. 8A)
The twisted portion 3b can have a larger section modulus than the twisted portions 1b and 2b of the conventional arm (FIG. 8 (b)). The strength can be improved.

[0030]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it is possible to obtain a press-formed product having a twist in the middle of the closed cross-sectional shape from a single material, and has a light-weight and high-rigidity twisted portion. It is possible to provide a high-quality pressed product having a wound cross section at low cost.

[Brief description of drawings]

FIG. 1 is a side view of a winding cross-section arm according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the winding cross-section arm shown in FIG.

FIG. 3 is a cross-sectional view showing a state of a mold and a raw material in an end bending step.

FIG. 4 is a cross-sectional view showing a state of a die and a raw material in a bending step.

FIG. 5 is a cross-sectional view showing a state of a die and a raw material in a joint bending process.

FIG. 6 is a cross-sectional view showing a state of a die and a raw material in the step of bending and bending following FIG.

FIG. 7 is a cross-sectional view showing the state of the mold and the raw material in the step of bending and bending following FIG.

FIG. 8 is a schematic view showing a welding surface of a winding cross-section arm and its welding counterpart component.

FIG. 9 is a three-dimensional schematic diagram showing the structure of a conventional closed cross-section arm having a twist.

[Explanation of symbols]

3 winding section arm 3a General department 3b twisted part 6,7 Bending mold 8, 9 Mold for combined bending

Claims (5)

[Claims] 1. A bending molding die for bending a flat surface portion of a material to form a curved cross-sectional shape having a closed end and an open end, and an open end of a material having the curved cross-sectional shape are combined to form a general portion and A die for a winding cross-section press, which includes a mold for a combined bending molding that forms a closed cross-sectional shape having a twisted portion with respect to the general portion, wherein the bend-molding die is one side surface of a material to be the twisted portion. And a forming surface for forming a final shape, wherein the combined bending mold has a forming surface that constrains one side surface of the twisted portion that forms the final shape, and the twisted portion by bending the other side surface that is the twisted portion. And a molding surface for bending the side surface of the raw material to be the general portion and aligning the open ends of the general portions with each other. 2. The combined bending molding die has a molding surface for constraining one side surface of the twisted portion having the final shape in the fixed mold, and the other side surface serving as the twisted portion is bent to bend the twisted portion. 2. The die for winding section press according to claim 1, wherein the movable die has a molding surface for bending the side surface of the raw material to be the general portion and for aligning the open ends of the general portions at the same time when the open ends are aligned. . 3. A molding surface of the movable die, which is involved in the joint bending of the twisted portion, has a portion having the same surface shape as the molding surface of the general portion involved in the joint bending, and is continuous with the portion. 3. The die for winding section pressing according to claim 2, further comprising a surface-shaped portion for guiding the other side surface of the twisted portion to one side surface of the twisted portion having the final shape. 4. A bending step of bending a material flat surface portion to form a curved cross-sectional shape having a closed end and an open end,
A winding cross-section pressing method comprising: a bending step of combining the open ends of the materials having the curved cross-sectional shape to form a closed cross-sectional shape having a general portion and a twisted portion with respect to the general portion, wherein the bending step includes: , Forming one side surface of the material to be the twisted portion into a final shape, and bending the other side surface to be the twisted portion while maintaining the shape of one side surface of the twisted portion forming the final shape in the mating bending step. A method for pressing a winding cross section, characterized in that, at the same time that the open ends of the twisted portions are aligned, the side surface of the material that becomes the general portion is bent to align the open ends of the general portions. 5. A rolled cross-section press-formed product molded by the rolled cross-section pressing method according to claim 4.