JP2000153314A - Manufacture of structural member for carbody - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of the structural member for the carbodies by which the number of manufacturing processes is greatly reduced, the cost of equipment for which is inexpensive and which is excellent in productivity. SOLUTION: In this manufacturing method of the structural member for the carbodies, by applying fluid pressure P inside a base stock in a state where the long-size cylindrical base stock 14 having an approximately elliptic cross-sectional shape is held inside bulging dies 17, 18, the wall surface of the base stock is bulged and formed by bulging, the member 19 having a rectangular cross-sectional shape is obtained. The movable direction of the bulging die 17 is made to approximately coincide with the direction of a long side of the approximately elliptic cross-sectional shape of the base stock 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a tubular structural member constituting a vehicle body of an automobile, and more particularly to a method of manufacturing a long cylindrical body-shaped structural member having a rectangular cross section.

[0002]

2. Description of the Related Art As a method of manufacturing a vehicle structural member of this type, for example, a method disclosed in Japanese Patent Application Laid-Open No. 5-178375 is known. A case of manufacturing a vehicle body structural member represented by an elongated tubular front side member 1 having a rectangular cross-sectional shape as shown in FIG. explain.

First, a front side member 1 is a vehicle body structural member provided in an engine room of an underbody to support an engine, and has a height H0 of a sectional shape.
Is sufficiently larger than its width B0 and has a rectangular
And a long cylindrical shape. Further, the front side member 1 is also a vehicle body structural member that absorbs energy at the time of a collision, and therefore, concave portions 2 that promote absorption of the collision energy are formed in the opposed vertical walls 3 respectively. The width B1 of the concave portion 2 formed in the opposed vertical wall 3 is naturally smaller than the product cross-sectional width B0, and has a bent portion with a bending radius R in the long side direction of the rectangular rectangular cross-sectional shape 9. .

When manufacturing the front side member 1 having such a shape, an elongated material 4 shown in FIG. 11 is used. The cross-sectional shape of the long material 4 is a circular cross-section having a cross-sectional circumference L1 substantially equal to the cross-sectional circumference L0 of the front side member 1.

[0005] This material 4 is subjected to a bending process corresponding to a bending radius R (not shown), and is then shown in FIG.
In the crushing process shown in FIGS. 2 (a) and 2 (b), the upper and lower heights are constrained by the upper and lower fixed dies 5 and 5, and the width direction is crushed by the left and right movable dies 6 and 6 to a product width B0 or less, thereby obtaining a substantially rectangular shape. It is molded to a cross-sectional shape 4 '. The portion corresponding to the concave portion 2 is crushed to a width B1 or less.

Next, the 4 'cylindrical member having a substantially rectangular cross section is held in the bulge molds 7 and 8 shown in FIGS. 13 (a) and 13 (b). The front side member 1 having a rectangular cross-sectional shape 9 is manufactured by applying a pressure such as a hydraulic pressure to the wall and bulging the wall surface by bulging.

[0007]

However, in such a conventional method of manufacturing a body structural member, a bending process or a crushing process in a product width direction is performed before a bulge forming step (see FIG. 13). However, since a large number of bulge preforming steps are required, there are problems that the number of manufacturing steps is large, the equipment cost is high, and the productivity is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a very small number of manufacturing steps, a low cost of equipment, and a method of manufacturing a member for a vehicle body structure excellent in productivity. The purpose is to provide.

[0009]

According to a first aspect of the present invention, there is provided a method for manufacturing a vehicle body structural member, comprising the steps of: forming a long cylindrical material having a substantially elliptical cross section into a bulge-shaped material; The method of manufacturing a body structural member according to claim 1, further comprising: applying a liquid pressure to the inside of the material while holding the material inside, and bulging and molding the wall surface by bulging to obtain a body structural member having a rectangular rectangular cross section. The movable direction of the mold substantially coincides with the long side direction of the substantially elliptical cross-sectional shape of the material.

According to the first aspect of the present invention, since the movable direction of the bulge shape substantially coincides with the long side direction of the substantially oval cross-sectional shape of the material, the desired molded product having the substantially rectangular cross-sectional shape can be obtained. It is extremely easy to form, which eliminates the need for a preforming step before bulging.

(2) Although not particularly limited in the above invention, the method of manufacturing a body structural member according to claim 2 is characterized in that the pair of bulge-type divided positions is formed by setting the long side of the material to be substantially elliptical in cross section. It is characterized in that it is offset in the movable mold direction from the center position in the direction.

According to the second aspect of the present invention, since the pair of bulge-type divided positions is offset in the movable mold direction from the center position of the substantially elliptical cross-sectional shape of the material in the long-side direction, the fixed mold material can be removed. The restraining force is increased, thereby preventing a problem that the material is sandwiched between the bulge-shaped divided surfaces.

(3) Although not particularly limited in the above invention, the method for manufacturing a body structural member according to claim 3 is characterized in that the movable direction of the bulge mold is an acute angle of a rectangular cross-sectional shape of a target molded product. It is characterized by being substantially coincident with the direction of the part.

According to the third aspect of the present invention, since the movable direction of the bulge mold substantially coincides with the direction of the acute angle of the rectangular cross-sectional shape of the target molded product, the deformed part having the acute angle part is formed. Even in the case of a molded product, the flowability of the material into the acute angle portion is increased, and the molded product can be favorably molded.

(4) Although not particularly limited in the above invention, a method of manufacturing a body structural member according to claim 4 is characterized in that the bulge is curved in the movable direction of the bulge. .

According to the fourth aspect of the present invention, since the bulge is curved in the movable direction of the bulge, the bending is performed simultaneously with the bulge. This allows
The bending process before bulging is not required.

(5) In the present invention, specific examples of the vehicle body structural member are not particularly limited, and include all members used for a vehicle body. In particular, as in the method of manufacturing a vehicle body structural member according to claim 4, the target vehicle structural member is a front side member, or,
As in the method for manufacturing a vehicle body structural member described above, it is more preferable that the target vehicle structural member is a side roof rail.

[0018]

According to the first to sixth aspects of the present invention, the pressing of the material having a substantially elliptical cross section by the clamping of the pair of bulge molds is performed without being sandwiched by the pair of bulge molds. Can be clamped. As a result, preforming before bulging, which is crushing in the horizontal and vertical directions of the product, becomes unnecessary, and productivity can be improved.

In addition to the above, according to the third aspect of the invention, the movable direction of the bulge mold is substantially the same as the product acute angle portion of the product cross section which is a rectangular cross section, so that a sharper acute angle portion is obtained. It is possible to manufacture a vehicle structural member having a rectangular cross section having the following.

According to the fourth aspect of the present invention, since the bulge mold which is curved in the movable direction of the movable bulge mold is used, the material does not need to be bent in the long side direction of the substantially elliptical cross section, and furthermore, the production is further improved. Performance can be improved.

In this case, since the long side direction of the substantially elliptical section having high surface rigidity with respect to the bending direction is set as the bending direction, no wrinkles or the like are generated at the time of bending, so that good bending can be performed. Can be.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a perspective view showing a raw material used in a first embodiment of a method for manufacturing a vehicle body structural member of the present invention, FIG. 2 is a cross-sectional view showing a bulge process employed in the first embodiment, and FIG. Is A- in FIG.
FIG. 4 is a cross-sectional view along the line BB of FIG. 2, and FIG. 5 is a cross-sectional view along the line CC of FIG.

In the present embodiment, a method for manufacturing the front side member 1 shown in FIG. 10 will be described as an example. In this case, a long cylindrical shape 20 having a substantially elliptical cross section 20 as shown in FIG. The member 14 is used as a material.

Regarding the dimensional relationship of the material 14, first, the shortest width of the rectangular rectangular cross-sectional shape 9 which is the cross-sectional shape of the front side member 1 shown in FIG. The width B1 of the provided recess for promoting absorption of collision energy and the width B2 of the short side of the long material 14 which is a cylindrical member having a substantially oval cross-sectional shape 20 shown in FIG.
And B2 ≦ B1.

In addition, second, the sectional circumference L0 of the front side member 1 as a product and the sectional circumference L2 of the material 14 are in a relationship of 0.8 × L0 <L2 <1.2 × L0. It is supposed to be.

The material 14 having such a shape is shown in FIG.
In the bulge process having the mold structure shown in FIGS. 5 to 5, firstly, as shown in FIG. 3A, the bulge is held inside a mold formed by a bulge movable mold 17 and a bulge fixed mold 18. You.

At this time, in this embodiment, the division position M between the movable bulge mold 17 and the fixed bulge mold 18 is the center position N in the long side direction of the substantially oval cross-sectional shape 20 which is the material cross section.
Is offset in the direction of the movable bulge 17. The moving direction of the bulge movable die 17 with respect to the bulge fixed die 18 is set to the long side direction of the substantially elliptical cross-sectional shape of the material 14.

Under such a configuration, after the bulge movable mold 17 is clamped as shown in FIG. 2B, a liquid pressure is applied to the inside of the tubular material 14 in this state, and the wall surface thereof is expanded by bulging. As shown in FIG. 3 (c), the material 14 having been formed into a substantially elliptical cross-sectional shape 20 is formed into a rectangular rectangular cross-sectional shape 1 as shown in FIG.
Mold into 9.

Next, the operation will be described. In the method for manufacturing a vehicle body structural member according to the present embodiment, the width B1 of the concave portion 2, which is the shortest width of the rectangular shape 19 in the rectangular shape of the front side member 1.
And the relationship of the short side width dimension B2 of the material 14 having the substantially elliptical cross-sectional shape 20 has a relationship of B2 ≦ B1, and the product cross-sectional circumference L
0 and the material sectional circumference L2 are 0.8 × L0 <L2 <1.
Since there is a relationship of 2 × L0, the width dimension B1 of the molding portion 21 of the concave portion 2 of the bulge fixing die 18 having the narrowest width will be described with reference to the bulge fixing die 18 of FIG. The material 14 having a substantially oval cross-sectional shape 20 is inserted and held by the bulge fixing die 18 as shown in FIG.

Since the movable direction of the bulge movable mold 17 is set to the long side direction of the substantially oval cross section of the material 14, the bulge movable mold 17 movable in the long side direction of the substantially oval sectional shape 20 of the material 14 is formed. When the mold is clamped, the substantially oval cross-sectional shape 20 of the material 14 is smoothly formed into the substantially rectangular cross-sectional shape 24 as shown in FIG. Therefore, it is not necessary to perform preforming before bulging, in which the height H2 of the long side of the material 14 having the substantially elliptical cross-sectional shape is crushed to the product cross-sectional height H0.

Further, by forming a pair of bulge molds 17 and 18 curved in the movable direction of the bulge movable mold 17, bending of the material 14 in the long side direction of the substantially oval cross-sectional shape 20 becomes unnecessary. This also makes it possible to improve productivity.

Further, since the long side direction of the substantially elliptical cross section 20 having high surface rigidity in the bending direction is set as the bending direction, no wrinkles or the like are generated at the time of bending.
Just by clamping the pair of bulge molds 17 and 18,
Good bending can be performed.

The material 14 has a substantially elliptical sectional shape 20.
Is pressed, the bulge movable mold 17 and the bulge fixed mold 1
8 is offset in the direction of the movable bulge 17 from the center position N in the long side direction of the substantially elliptical cross section 20, which is the cross section of the material, so that the deformation of the substantially oval cross sectional shape 20 of the raw material 14 is fixed to the bulge. Since the material 14 is sufficiently restrained by the mold 18, the material 14 can be formed without sandwiching the material 14 between the divided surfaces of the movable bulge 17 and the fixed bulge 18.

Next, as shown in FIG.
When a liquid pressure is applied to the inside of the container and the wall surface is bulged by bulging, a substantially rectangular rectangular cross-sectional shape 24 shown in FIG.
Can be bulge-formed on the front side member 1 having a rectangular cross-sectional shape 19.

On the other hand, the mold ends 26 of the pair of bulge molds 17 and 18 with which the ends 25 of the material 14 are in contact are the cross section C in FIG.
As shown in FIGS. 5A to 5C showing −C, when the pair of bulge molds 17 and 18 are clamped, a circular shape is formed.
The circumference L3 of the circular shape is equal to or longer than the circumference L2 of the material section. As a result, the material end portion 25 is formed into the substantially oval cross-sectional shape 20 into the substantially circular cross-sectional shape 27 by clamping the bulge movable mold 17.

Then, the seal base 23 shown in FIG. 2 is press-fitted into the substantially round cross-sectional shape 27 which is the end portion 25 of the material 14, and as shown in FIG. It is molded or expanded into a shape 28 and can be bulged by applying a hydraulic pressure to the inside of the material 14 as described above.

The long material 14 may be an extruded member made of an aluminum alloy or a long material obtained by roll-forming an iron plate. Further, in the illustrated embodiment, the present invention has been described using the vertical press movable in the vertical direction as the bulge molds 17 and 18, but the horizontal press performing the mold clamping in the horizontal direction or the cam mechanism is used. A mold using a lateral clamping mechanism also has the same effect as described above, except that the clamping direction is different.

Second Embodiment FIGS. 6 to 9 show another embodiment of the present invention. The vehicle body structural member according to the present embodiment has a rectangular
The side roof rail 41 is a cylindrical member. FIG.
As shown in FIG. 7 showing a cross section DD of FIG. 7, the side roof rail 41 has an acute angle portion 51 and a rectangular cross-sectional shape 49 having a product cross-sectional height H3 sufficiently larger than the product cross-sectional width B3. It is.

A long cylindrical material 44 used in the present manufacturing method
Has a substantially elliptical cross-sectional shape 50 as shown in FIG. 8, and more specifically, a product cross-sectional width B3 of the side roof rail 41.
And the short side width B4 of the substantially elliptical cross-sectional shape 50 that is the material 44 is B4 ≦ B3, and the product cross-sectional circumference L4 and the material cross-sectional circumference L6 of the side roof rail 41 are 0.
The dimensional relationship is 8 × L4 <L5 <1.2 × L4.

The material 44 having such a shape is shown in FIG.
In the bulge process having the mold structure shown in (1), the bulge is first held inside a mold formed by the movable bulge 47 and the fixed bulge 48.

At this time, in the present embodiment, the dividing position M between the movable bulge mold 47 and the fixed bulge mold 48 is the center position N in the long side direction of the substantially elliptical cross-sectional shape 50 which is the material cross section.
From the bulge movable mold 47. The movable direction of the bulge movable mold 47 with respect to the bulge fixed mold 48 is set to the long side direction of the substantially oval cross-sectional shape of the material 44. Further, the movable direction of the bulge movable mold 47 is
A product acute angle portion 51 of a product cross section having a rectangular cross-sectional shape 49
Also in the approximate direction.

Under such a configuration, after the bulge movable mold 47 is clamped as shown in FIG. 3B, a liquid pressure is applied to the inside of the tubular material 44 in this state, and the wall surface thereof is expanded by bulging. As shown in FIG. 3 (c), the material 44, which had been formed into a substantially elliptical cross-sectional shape 50, was replaced with a rectangular cross-sectional shape 4 as shown in FIG.
Mold into 9.

That is, the movable direction of the bulge movable mold 47 is
As shown in FIG. 9B, the bulge movable mold 47 is formed in the direction of the long side of the substantially oval cross section 44 and substantially in the direction of the product acute angle portion 51 of the product cross section having the rectangular rectangular cross section 49.
When the mold is clamped, the substantially oval cross-sectional shape 50 of the material 44 becomes
The material is formed into a substantially rectangular cross-sectional shape 54 while the material flows in the direction of the acute angle portion 52 of the mold into which the material does not easily flow. Then, as shown in FIG. 3C, when bulging is performed by applying a liquid pressure to the inside of the cylindrical material 44, the side roof rail 41 having a rectangular cross-sectional shape 49 having an acute angle portion 51 is favorably manufactured.

The material end is similar to that of the first embodiment.
By pressing the pair of bulge molds 47 and 48 by the mold clamping and press-fitting the seal base 23, the bulge molds 47 and 48 are formed or expanded into a round cross-sectional shape capable of hydraulic sealing.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting 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.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a raw material used in a first embodiment of a method for manufacturing a body structural member according to the present invention.

FIG. 2 is a cross-sectional view showing a bulge process used in the first embodiment of the method for manufacturing a vehicle body structural member of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a sectional view taken along line BB of FIG. 2;

FIG. 5 is a sectional view taken along line CC of FIG. 2;

FIG. 6 is a front view showing a product (molded product) manufactured in a second embodiment of the method for manufacturing a body structural member according to the present invention.

FIG. 7 is a sectional view taken along line DD of FIG. 6;

FIG. 8 is a cross-sectional view showing a raw material used in a second embodiment of the method of manufacturing a vehicle body structural member according to the present invention.

FIG. 9 is a cross-sectional view illustrating a bulge process used in the second embodiment of the method of manufacturing a vehicle body structural member according to the present invention.

FIG. 10 is a perspective view showing a front side member of a general automobile.

FIG. 11 is a cross-sectional view showing a material used in a conventional manufacturing method.

FIG. 12 is a cross-sectional view showing a preforming step employed in a conventional manufacturing method.

FIG. 13 is a cross-sectional view showing a bulge step used in a conventional manufacturing method.

[Explanation of symbols]

 14, 44: material 17, 47: movable type (bulge type) 18, 48: fixed type (bulge type) 51: acute angle portion M: bulge type dividing surface

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B62D 65/00 B62D 65/00 A

Claims (6)

[Claims] In a state in which a long cylindrical material having a substantially elliptical cross section is held inside a bulge mold, a liquid pressure is applied to the inside of the material, and the wall surface thereof is bulged by bulging. In the method for manufacturing a vehicle body structural member having a rectangular cross-sectional shape, a movable direction of the bulge shape substantially coincides with a long side direction of the substantially elliptical cross-sectional shape of the material. A method for manufacturing a body structural member. 2. The vehicle body according to claim 1, wherein said pair of bulge-shaped divided positions are offset in a movable mold direction from a center position in a long side direction of the substantially elliptical cross-sectional shape of said material. A method for manufacturing a structural member. 3. The body structure according to claim 1, wherein the movable direction of the bulge mold substantially coincides with a direction of an acute angle portion of a rectangular cross-sectional shape of a target molded product. Manufacturing method of the member. 4. The method for manufacturing a vehicle body structural member according to claim 1, wherein said bulge type is curved in a movable direction of said bulge type. 5. The method for manufacturing a vehicle body structural member according to claim 1, wherein the target vehicle structural member is a front side member. 6. The method according to claim 3, wherein the target body structural member is a side roof rail.