JPH08174047A - Method for forming structural member for automobile using hollow extruded profile - Google Patents

Abstract

PURPOSE: To provide a method for forming a structural member for automobiles using hollow extruded profiles with a high production efficiency without requiring cutting and without degrading strength in forming of the structural member for automobiles shaped to have the spacings between the opposite walls of the hollow extruded profiles varying partially in a longitudinal direction. CONSTITUTION: The hollow extruded profiles are formed to the shape which the spacing between the opposite walls 1b, 1c of either of two sets of the walls (1b, 1c) (1d, 1d) of the hollow extruded profiles vary partially in the longitudinal direction in the method for forming the structural member for automobiles using the hollow extruded profiles having an almost rectangular section. At that time, easily curvable shape parts 1d-o, 1d-i which are liable to curve in the form of recessing into the inside of the hollow of the hollow extruded profiles are previously formed in the respective other opposite walls 1d, 1d of the hollow extruded profiles at the time of extrusion molding. These easily curvable shape parts 1d-o, 1d-i are partially curved in the longitudinal direction, by which the spacing between the one opposite walls 1b, 1c of the hollow extruded profiles is partially decreased, by which the hollow extruded profiles are formed to the structural member 1 for automobiles having the desired shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structural member for an automobile body using a hollow extruded profile, in which the distance between opposing walls of the hollow extruded profile is partially different in the longitudinal direction. The present invention relates to a method for molding an automobile structural member using a hollow extruded profile suitable for molding the structural member.

[0002]

2. Description of the Related Art Conventionally, structural members of automobile bodies are generally
As shown in FIG. 12, a floor panel 102 obtained by press-forming a steel sheet and a cross member 103 are joined by spot welding 104 to form a closed cross-section member 101.

By the way, in recent years, in order to reduce the weight of an automobile body, an example of using an aluminum material has been increasing.

However, if the cross member 103 mounted on the upper surface of the floor panel 102 of the vehicle body as shown in FIG. 12 and bearing the lateral strength of the vehicle body is simply replaced with an aluminum plate material, the aluminum plate becomes a steel sheet. Since the strength and rigidity are lower than that of the conventional one, it is necessary to increase the plate thickness in order to cope with a side collision or the like, and the weight reduction effect is reduced.

Therefore, it is considered that both strength and weight reduction can be achieved by applying a hollow extruded shape member having a closed cross-section structure having a large deformation resistance in the axial compression direction per unit weight to a structural member of a vehicle body. In recent years, attention has been paid to the application of hollow extruded profiles to vehicle body structural members.

However, for example, a closed cross-section member 101 composed of a floor panel 102 and a cross member 103 shown in FIG. 12 has a tunnel at a central portion in the longitudinal direction in order to avoid interference with an exhaust pipe or a power transmission shaft of an automobile. The floor tunnel portion 101a is formed into a bent shape. Therefore, in order to prevent the upper side wall 103c of the cross member 103 in the floor tunnel portion 101a from protruding into the living room, The height from the flange portion 103b to the upper side wall 103c is lower than that of the portion other than the floor tunnel portion 101a.

For this reason, when a hollow extruded shape is used to form the closed cross-section member 101, for example, as shown in FIG. 13, flange portions 111b are provided on both sides of the lower side wall. And extruded profile 111 whose cross section is in the shape of a letter
After the floor tunnel portion 111a is formed by bending the vicinity of the central portion in the longitudinal direction of the floor tunnel by means such as press bending or draw bender, the upper sidewall 11 of the floor tunnel portion 111a is formed.
The required shape was obtained by cutting 1c.

[0008]

However, in the vehicle body structural member using the extruded shape member 111 obtained by such means, one of the upper side walls 111c corresponding to the floor tunnel portion 111a of the extruded shape member 111 is formed. Since the section is cut, the cross-sectional area of the floor tunnel section 111a is reduced, the strength is reduced against compression of the extruded profile 111 from the longitudinal direction, and in order to obtain the required shape, the upper side wall 111c is cut. Since the shape of the curved portion has a complicated curved shape, there is a problem that the machining process takes a lot of time and the production efficiency becomes extremely low, and it is a problem to solve this problem.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above conventional problems, and forms a structural member for automobiles in which the intervals between the opposing walls of the hollow extruded profile are partially different in the longitudinal direction. In doing so, it is an object of the present invention to provide a method for molding a structural member for an automobile using a hollow extruded shape member, which does not require a cutting process, does not deteriorate in strength, and has high production efficiency.

[0010]

A method for molding a structural member for an automobile using a hollow extruded profile according to the present invention is, as a claim 1, a method for molding an automobile body using a hollow extruded profile having a substantially rectangular closed cross section. In the method for forming a structural member, of two sets of opposing walls of a hollow extruded profile, one of the opposing walls is formed into a shape having a partially different interval in the longitudinal direction. Each easy-to-bend shape is formed in advance during extrusion molding so that the opposing walls are recessed in the hollow inside of the hollow extruded shape, and the easily-bent shape is partially bent in the longitudinal direction. Thus, the interval between the walls facing each other of the hollow extruded profile is partially reduced to form an automobile structural member having a desired shape, and the mold surface of the desired automobile structural member is defined as claim 2. Mold formed A hollow extruded profile is set and pressed by a pressing die such as a pressing machine in a direction to reduce the distance between the opposing walls to partially deform the easily bendable shape part in the longitudinal direction of the hollow extruded profile. The outer notch formed along the longitudinal direction at the central portion of the outer surface of each wall, and the inner surface of each wall. And a depth h1 of the outer notch and a depth h2 of the two inner notches are: h1 ≧ h2 And satisfying that h1 is 0.3 t or more and less than 0.7 t and h2 is 0.2 t or more and less than 0.7 t with respect to the plate thickness t, and the other opposing walls are defined as claim 5. The formed easily bendable shape is the center of each wall A curved central bead that is concave with respect to the outer surface of the wall and that is convex with respect to the inner surface of the wall, and an outer surface of the wall that is formed symmetrically with respect to the central bead. 7. A structure comprising two opposite-sided beads each having a curved shape which is convex with respect to the inner surface of the wall and concave to the inner surface of the wall, and the easily bendable shape portion formed on each of the other opposing walls is defined as claim 6. A central bead having a curved shape that is formed along the longitudinal direction at the central portion of the wall and is concave with respect to the outer surface of the wall and convex with respect to the inner surface of the wall, and is a wall that is continuous on both sides of the central bead and is hollow. A configuration comprising an extruded profile and a slanted wall portion that is inclined in a recessed manner, and claim 7, wherein one or both of the central bead and the both-side beads are thicker than other portions. 8, bending of the central bead and the inclined wall It is characterized in that a structure to be thicker than one or both the thickness of the other parts of the.

Similarly, a method for molding a structural member for automobiles using the hollow extruded shape member according to the present invention is as follows.
In a method of molding a structural member for an automobile body using a hollow extruded profile having a substantially rectangular closed cross section, in two sets of opposed walls of the hollow extruded profile, one of the opposing walls has a space in the longitudinal direction. When molding into a different shape, the other opposed wall of the hollow extruded shape is bent in the hollow inside of the hollow extruded shape to form a bent shape part in advance during extrusion molding, By applying a pressure to the hollow inner wall surface of the hollow extruded profile to partially expand the bent shape portion in the longitudinal direction, the interval between the opposing walls of the hollow extruded profile is partially increased to obtain a desired shape. The structure is formed into a structural member for automobiles according to claim 10, and the structure is such that the hollow internal wall surface of the hollow extruded shape member is partially expanded by applying pressure by hydraulic bulge molding. Do It is the means of the eye.

[0012]

According to the method of molding a structural member for an automobile using the hollow extruded profile according to claim 1 of the present invention, in the hollow extruded profile having a substantially rectangular closed cross section, one of the opposing walls has a space therebetween. A configuration in which when forming a partially different shape in the longitudinal direction, an easily bendable shape portion is formed in advance on each of the other opposing walls during extrusion molding, and this easily bendable shape portion is partially bent in the longitudinal direction. As a result, a structural member for an automobile having a desired shape in which the interval between the walls facing each other of the hollow extruded shape is partially different is formed with high production efficiency without the need for cutting and the reduction in strength. The Rukoto.

According to a second aspect of the present invention, there is provided a method for molding an automobile structural member using a hollow extruded shape member, which comprises setting the hollow extruded shape member in a forming die having a desired molding surface of the automobile structural member. Productivity by using a press die such as a press to press the easily bendable shape part in the longitudinal direction of the hollow extruded shape by pressing it in a direction that reduces the distance between the opposing walls. Will be high.

According to a third aspect of the present invention, a method for molding a structural member for an automobile using a hollow extruded profile is an outer side in which an easily bendable shape portion is formed along a longitudinal direction at a central portion of an outer surface of each wall. The notch and the two inner notches formed on the inner surface of each wall at symmetrical positions with respect to the outer notch allow the outer notch and the inner notch to become the starting points of bending, thereby making Thus, a structural member for an automobile having a desired shape is formed in which the intervals between the opposing walls are partially different.

According to a fourth aspect of the present invention, in the method for molding an automobile structural member using a hollow extruded shape member, the depths of the outer notch and the inner notch are set as described above, so that when bent, A reliable bend can be obtained without causing a defect such as a crack in the notch portion.

According to a fifth aspect of the present invention, there is provided a method of molding a structural member for an automobile using a hollow extruded shape member, wherein an easily bendable shape portion is formed on a central portion of each wall along the longitudinal direction of the outside of the wall. A curved central bead that is concave to the side surface and convex to the inner surface of the wall, and convex to the outer surface of the wall and concave to the inner surface of the wall formed symmetrically with respect to the central bead When the bead portion is bent, the plate thickness of the bead portion does not decrease substantially by using the curved two-sided bead on both sides, so that the elongation value of the material is relatively small. Also in the strength member, cracks and the like are less likely to occur in the bent bead portion.

According to a sixth aspect of the present invention, there is provided a method for molding a structural member for an automobile using a hollow extruded shape member, wherein an easily bendable shape portion is formed on a central portion of each wall along the longitudinal direction of the outside of the wall. Consists of a curved central bead that is concave to the side surface and convex to the inner surface of the wall, and a sloped wall portion that is a wall that connects both sides of the central bead and that slopes inwardly in the hollow extruded profile. As a result, the slanted wall portion is inclined inwardly of the hollow extruded shape to facilitate bending, and since the center bead is also the starting point of bending, reliable bending occurs. Therefore, a structural member for automobile having a desired shape can be obtained.

According to a seventh aspect of the present invention, in the method of molding a structural member for an automobile using a hollow extruded shape member, one or both of the central bead and the both-side beads are made thicker than other portions. This prevents defects such as cracks in the bent bead portion, and also prevents reduction in strength due to thinning during bending.

According to the eighth aspect of the present invention, in the method for molding an automobile structural member using a hollow extruded shape member, one or both of the central bead and the bent portion of the inclined wall portion are made thicker than the other portions. With such a configuration, the same effect as that of claim 7 is achieved.

According to a ninth aspect of the present invention, there is provided a method of molding a structural member for an automobile using a hollow extruded profile, wherein the other opposing walls of the hollow extruded profile are recessed into the hollow interior of the hollow extruded profile. By forming a bent shape part bent in advance during extrusion molding and applying a pressure to the hollow inner wall surface of the hollow extruded shape member to partially expand the bent shape part in the longitudinal direction, A structural member for an automobile having a desired shape in which the interval between the walls facing each other of the extruded shape is partially different is formed with high production efficiency without the need for cutting and the reduction in strength.

According to a tenth aspect of the present invention, in the method of molding a structural member for an automobile using a hollow extruded shape member, a pressure is applied to a hollow inner wall surface of the hollow extruded shape member by hydraulic bulge molding to partially expand the hollow inner wall surface. With the configuration, the partial expansion molding in the longitudinal direction of the bent portion can be relatively easily performed.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective explanatory view showing one embodiment of an automobile structural member (cross member) formed by the method for forming an automobile structural member using the hollow extruded shape member according to the present invention.

A cross member 1 which is a structural member for an automobile shown in FIG. 1 is a floor tunnel portion 1a which is bent in a tunnel shape at a central portion in a longitudinal direction in order to avoid interference with an exhaust pipe or a power transmission shaft of the automobile. Is formed, and the cross-sectional shape of the floor tunnel portion 1a in the direction perpendicular to the longitudinal direction is a shape as shown in FIG. 2 (b), and other than the floor tunnel portion 1a, that is,
The shape of the cross section perpendicular to the longitudinal direction of the unbent portion is as shown in FIG.
In FIG. 2B, the interval between the upper and lower side walls 1c and 1b facing each other is narrower than that in FIG. 2A.

This is to prevent the upper side wall 1c from protruding into the interior of the automobile as described above. To mold the cross member 1 having such a shape, first, referring to FIG.
A hollow extruded shape having the shape shown in FIG. 2 (the cross-sectional shape is the same as that shown in FIG. 2A) is molded.

The hollow extruded profile (1) shown in FIG. 3 (and FIG. 2 (a)) has a substantially rectangular shape in the longitudinal direction which is composed of an upper side wall 1c, a lower side wall 1b, and two opposite side walls 1d. It has a closed cross section. Further, flanges 1b-f for joining with other members are formed on both sides of the lower side wall 1b.

Further, an outer notch 1d-o, which is a substantially V-shaped groove, is formed along the longitudinal direction at the central portion of the outer surface of the two side walls 1d, and the inner side surfaces of the two side walls 1d are formed. Has two inner notches 1d-i formed at symmetrical positions with respect to the outer notches 1d-o.

The hollow extruded profile (1) formed in such a shape is set in, for example, a press bending die as shown in FIG. 4, and the floor tunnel portion 1a is bent at the same time as the floor. Upper side wall 1 in the tunnel portion 1a
Crushing is performed to reduce the distance between c and the lower side wall 1b.

In FIG. 4, an upper die 8 and a lower die 9 on which a die surface having a shape substantially conforming to the floor tunnel shape is formed.
Then, the hollow extruded profile (1) is sandwiched in such a manner that the upper side wall 1c and the lower side wall 1b thereof are pressed, and the core 10 is inserted from both ends of the hollow extruded profile (1). 8 and the lower mold 9 are pressed in the direction of compressing the hollow extruded shape material (1) by using a pressing mold such as a press machine, and
The cross member 1 having substantially the same shape as that shown in FIG.

At this time, the sectional shape of the floor tunnel portion 1a is, as shown in FIG. 2B, bent from the portion where the outer notch 1d-o and the inner notch 1d-i are formed. There is.

This is because when a compressive force is applied to the side wall 1d, the outer notch 1d-o and the inner notch 1 are formed in the side wall 1d.
This is because the formation of d-i serves as the starting point for bending.

On the other hand, the cross-sectional shape of the portion of the cross member 1 other than the floor tunnel portion 1a, that is, the portion in which the core 10 is inserted is restrained by the core 10 from deforming the hollow shape due to the compressive force. 2A has the shape shown in FIG.

In this way, the bending and the crushing are simultaneously performed, and then the core 10 is extracted,
It is possible to obtain the cross member 1 having a predetermined shape.

Now, in FIG. 5, a JIS-A7003 (aluminum alloy for extrusion) material is used as the material of the hollow extruded profile, and the depth h1 of the outer notch 1d-o and the inner notch 1d in FIG. 2 (a) are used. FIG. 6 shows the results of examining the appropriate range of the notch depth by performing a crushing working experiment by changing the depth h2 of −i variously.

As shown in FIG. 5, when the thickness of the side wall 1d is t, the center outside notch depth h1 does not bend well if it is less than 0.3t, and cracks occur when it is 0.7t or more. When the inner notch depth h2 was less than 0.2 t, the notch did not bend well, and when it was 0.7 t or more, cracking occurred.

Experiments have revealed that good crushing can be performed when the outer notch depth h1 and the upper and lower notch depths h2 have a relationship of h1 ≧ h2.

In this embodiment, the shape of the notch is approximately V.
Although the groove is a V-shaped groove, other than this, for example, a wide U-shaped groove 12 as shown in FIG.
Similar effects can be obtained even if the groove 13 is a U-shaped groove 13 having a parallel portion on the bottom surface as shown in FIG. 6B.

Further, in this embodiment, the floor tunnel section 1
As for the crushing process for reducing the distance between the upper side wall 1c and the lower side wall 1b, as shown in FIG. 2B, the crushing process is performed until the bent side walls 1d are in close contact with each other. Alternatively, it may be in a semi-crushed state in which a required distance between the upper side wall 1c and the lower side wall 1b is obtained.

The outer notch 1d-o and the inner notch 1
The setting position of d-i and the relative positional relationship are not limited to those in this embodiment, and may be arbitrarily set at the position where the side wall 1d is to be bent.

In this embodiment, the bending and crushing of the floor tunnel portion 1a are performed simultaneously by pressing, but the bending and crushing may be performed in separate steps. The processing may use another method, for example, a draw bender or a multi bender.

FIG. 7 is a sectional explanatory view showing another embodiment of a structural member for automobile molded by the method for molding a structural member for automobile using the hollow extruded shape member according to the present invention. As shown in FIG. 7A, the material (1) is concave with respect to the outer surface of the side wall 1d formed along the longitudinal direction at the central portion of each side wall 1d and with respect to the inner surface of the side wall 1d. A curved central bead 1d-c having a convex shape and a curved shape convex to the outer surface of the side wall 11d and concave to the inner surface of the side wall 1d formed at symmetrical positions with respect to the central bead 1d-c. Two double-sided beads 1d-s are extruded.

Then, the straight hollow hollow extruded shape member (1) having such a cross-sectional shape is bent in the same manner as in the above-mentioned embodiment, and the floor tunnel portion 1a is bent and the upper side wall 1c and the lower side wall of the floor tunnel portion 1a are bent. Simultaneous crushing work for reducing the distance from 1b is performed.

At this time, the cross-sectional shape of the floor tunnel portion 1a is bent at the central bead 1d-c and the side beads 1d-s, which are likely to be bent, as shown in FIG. 7 (b). Upper side wall 1c and lower side wall 1
It is possible to use the cross member 1 in which the distance from b is partially reduced.

The portions other than the floor tunnel portion 1a of the cross member 1 are shown in FIG.
The initial cross-sectional shape shown in is maintained. Thus, the predetermined cross member 1 in which the distance between the upper side wall 1c and the lower side wall 1b is partially different is obtained.

Unlike this embodiment, this embodiment does not reduce the substantial plate thickness at the bead portion, so even in the case of a high-strength member having a comparatively small elongation value of the material, the bead portion is cracked by the crushing process. The feature is that it is unlikely to occur.

Further, as will be described later, for a material having a smaller elongation value, even if the plate thickness in the vicinity of one or both of the central bead 1d-c and the both-side beads 1d-s is slightly increased. Good.

FIG. 8 is a cross-sectional explanatory view showing still another embodiment of the hollow extruded profile used in the method of molding a structural member for an automobile according to the present invention. The hollow extruded profile (1) is shown in FIG. ,
A thickened central bead 1d having a curved shape that is formed along the longitudinal direction at the central portion of each side wall 1d and is concave with respect to the outer surface of the side wall 1d and convex with respect to the inner surface of the side wall 1d.
-C and four inclined wall portions 1d-w that are walls that are continuous with both sides of the central bead 1d-c and that are inclined in a concave shape inside the hollow extruded profile (1) are formed.

Simultaneously with the hollow extruded shape material (1) as described above, a crushing process for reducing the distance between the upper side wall 1c and the lower side wall 1b in the floor tunnel portion 1a is carried out by pressing or the like as in the above embodiment. By doing so, the same action as that of the above-described embodiment can be achieved, whereby the distance between the upper side wall 1c and the lower side wall 1b can be partially reduced.

In this embodiment, the side wall 1d is previously prepared.
Since the central part of the is bent inward, it can be easily crushed, and since the thickened central bead 1d-c is formed in the central part, the plate thickness is reduced by bending. However, the required strength is maintained. Further, in this embodiment, only the central beads 1d-c are thickened, but the inclined wall portion 1d may be formed if necessary.
The bent portion 1d-k of -w may be thickened.

FIG. 9 is a sectional explanatory view showing still another embodiment of the automobile structural member formed by the method for forming an automobile structural member using the hollow extruded profile according to the present invention. The example is different from the above-described examples, and the hollow extruded profile (1) has a cross-sectional shape as shown in FIG.
Is extruded with the initial shape as the initial shape, pressure is applied to the hollow inner wall surfaces of both sides of the hollow extruded profile (1), and both side walls 1d are partially stretched and expanded in the longitudinal direction. The shape of the cross member 1 is obtained.

Specifically, when the side wall 1d of the hollow extruded shape (1) is bent in the hollow inside of the hollow extruded shape (1) to be bent in a concave shape, the bent shape portion 1d-b is preliminarily extruded. The upper die 11 and the lower die 12 on which a die surface having the shape of the floor tunnel portion 1a as shown in FIG.
Preliminary bending work is performed by the forming die.
At this time, the distance between the upper mold 11 and the lower mold 12 is such that the distance between the upper side wall 1c and the lower side wall 1b does not decrease.

Then, the hollow extruded shape member, which has been subjected to the bending process in this way and in which the approximate shape of the floor tunnel portion 1a is formed, is formed into a hydraulic bulge upper die 13 and a hydraulic bulge lower die 14 shown in FIG. Set between.

The hydraulic bulge upper mold 13 and the hydraulic bulge lower mold 14 are formed with a mold surface in the shape of the floor tunnel portion 1a, and the hydraulic bulge upper mold 13 and the liquid bulge upper mold 13 in the portion other than the floor tunnel portion 1a are formed. The pressure bulge lower die 14 is formed so that the space between the upper side wall 1c and the lower side wall 1b becomes a required distance when the bent shape portion 1d-b of the hollow extruded shape member straightens and expands. ing.

Then, the hydraulic bulge upper die 13 is pressed in the direction of the hydraulic bulge lower die 14 using a pressing machine or the like to perform die clamping, and the hydraulic pressure P is applied from both ends of the hollow extruded profile. To increase the internal pressure of the hollow extruded profile.

By doing so, in the hollow extruded profile (1) having the cross-sectional shape shown in FIG. 9A, the bent shape portions 1d-b on both sides in the longitudinal direction of the hollow extruded profile are directed to the outside of the hollow extruded profile. Therefore, since the bent shape portion 1d-b expands outward, the distance between the upper side wall 1c and the lower side wall 1b increases. Then, when the internal pressure of the hollow extruded shape is further increased, the upper side wall 1c and the lower side wall 1b are brought into close contact with the hydraulic bulge upper die 13 and the hydraulic bulge lower die 14 which are in the mold clamping state.

As a result, the cross-sectional shape of the hollow extruded shape other than the floor tunnel portion 1a becomes a substantially rectangular cross-sectional shape as shown in FIG. 9B, and the cross member 1 has a desired shape.

In the present embodiment, the bending process of FIG. 10 and the hydraulic bulge forming process of FIG. 11 were performed in separate molds and processes, but pre-bending was not performed, and bending and expansion were performed using a hydraulic bulge mold. Machining may be performed in the same process, and during bending, bending is performed while suppressing the collapse of the cross-sectional shape while slightly applying hydraulic pressure to the internal space of the hollow extruded shape. The pressure may be increased to expand the bent shape portions 1d-b of the hollow extruded shape portion other than the floor tunnel portion 1a.

In these processing steps, heat treatment for adjusting the mechanical properties of the material may be appropriately performed at the same time.

Further, the cross member 1 which is a structural member for automobile having the floor tunnel portion 1a has been described, but the application of the present invention is not limited to the member having the bent portion such as the floor tunnel portion 1a. is not.

[0060]

As described above, according to the method for molding a structural member for an automobile using the hollow extruded profile according to the first aspect of the present invention, one of the opposing walls of the hollow extruded profile is formed. It is possible to efficiently produce automobile structural members of desired shapes with different gaps, and without the need for cutting,
Since the cross-sectional area in the direction perpendicular to the longitudinal direction, which is responsible for the compressive force, does not decrease, the strength can be sufficiently maintained, and an excellent effect that a lightweight and high-strength structural member for an automobile can be obtained is brought about.

According to the second aspect of the present invention,
The effect is that the productivity can be further improved.

With the configuration according to claim 3 of the present invention,
Since the outer notch and inner notch are the starting points of bending,
It is possible to form an automobile structural member having a desired shape in which the distance between the opposing walls of one of the hollow extruded profiles is partially different in the longitudinal direction.

According to the fourth aspect of the present invention,
When bent, there is an effect that it is possible to surely bend without causing defects such as cracks in the notch portion.

According to the fifth aspect of the present invention,
When the bead portion bends, the substantial plate thickness at the bead portion does not decrease, so even in a high-strength member with a relatively small elongation value of the material, cracks etc. are unlikely to occur in the bent bead portion. The effect is that it can be.

According to the sixth aspect of the present invention,
Since the inclined wall portion is inclined inwardly of the hollow extruded shape so as to be easily bent, and the central bead also serves as a starting point of bending, an effect that it can be surely bent is brought about. With the configuration according to claim 7 of the present invention, it is possible to prevent defects such as cracks in the bead portion that bends, and to prevent a decrease in strength due to thinning during bending. Be done.

According to the eighth aspect of the present invention,
An effect similar to that of claim 7 is brought about.

According to the method for molding a structural member for an automobile using the hollow extruded profile according to the ninth aspect of the present invention, one of the walls of the hollow extruded profile has a desired shape in which the intervals between the opposing walls are partially different. It can efficiently produce structural members for automobiles, does not require cutting work, and does not reduce the cross-sectional area in the direction perpendicular to the longitudinal direction that receives compressive force, so it can maintain sufficient strength, is lightweight and has high strength. The excellent effect that a structural member for automobiles is obtained is brought about.

According to the structure described in claim 10 of the present invention, there is an effect that the bent shape portion can be partially expanded in the longitudinal direction relatively easily.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view of an automobile structural member (cross member) showing an embodiment of a method for molding an automobile structural member using a hollow extruded shape member according to the present invention.

2 is a cross-sectional explanatory view of a portion other than the floor tunnel portion ((a) of FIG. 2) of the structural member for an automobile of FIG. 1 and a cross-sectional explanatory view of the floor tunnel portion ((b) of FIG. 2).

FIG. 3 is a perspective explanatory view showing an example of a hollow extruded shape member used in the molding method of the present invention.

FIG. 4 is an explanatory view showing a state of bending and crushing by the forming die of the hollow extruded shape material shown in FIG.

FIG. 5 is an explanatory diagram showing appropriate values of depths of a central outer notch and upper and lower inner notches.

FIG. 6 is an explanatory view showing another embodiment of the shape of the notch portion.

7 is a cross-sectional explanatory view showing another embodiment of the method for molding a structural member for an automobile using the hollow extruded shape member according to the present invention, which is a cross-sectional explanatory view of a portion other than the floor tunnel portion (see FIG. 7). (A)) And sectional explanatory drawing of a floor tunnel part ((b) of FIG. 7).

FIG. 8 is a cross-sectional explanatory view showing still another embodiment of the method for molding an automobile structural member using the hollow extruded profile according to the present invention.

9 is a sectional explanatory view showing still another embodiment of the method for molding an automobile structural member using the hollow extruded profile according to the present invention, which is a sectional explanatory view of the floor tunnel portion ((a in FIG. 9)). )) And a cross-sectional explanatory view of a portion other than the floor tunnel portion ((b) of FIG. 9).

FIG. 10 is an explanatory view showing a state of bending of the hollow extruded shape material shown in FIG. 9 by a forming die.

11 is an explanatory view showing a state of expansion processing of the hollow extruded shape material shown in FIG. 9 by hydraulic bulge molding.

FIG. 12 is a perspective explanatory view showing an example of an automobile structural member obtained by joining conventional plate materials by spot welding.

FIG. 13 is a perspective explanatory view showing an example of an automobile structural member (cross member) using an extruded profile obtained by a conventional method.

[Explanation of symbols]

 1 Cross Member (Structural Member for Automobile) (1) Hollow Extruded Member 1a Floor Tunnel Part 1b Lower Side Wall 1c Upper Side Wall 1d Side Wall 1d-o Outer Notch (Easy Bend Shaped Part) 1d-i Inner Notch (Easy Bend Shaped Part) 1d -C Central bead (easy-bending shape part) 1d-s Both-side beads (easy-bending shape part) 1d-w Sloping wall part (easy-bending shape part) 1d-b Bending-shape part 8 Upper mold 9 Lower mold 10 Core 11 Upper Mold 12 Lower mold 13 Hydraulic bulge Upper mold 14 Hydraulic bulge Lower mold

Claims (10)

[Claims] 1. A method for forming a structural member for an automobile body using a hollow extruded profile having a substantially rectangular closed cross section, wherein, between two opposing walls of the hollow extruded profile, one of the opposing walls is spaced. When forming into a partially different shape in the longitudinal direction, the easy-to-bend shape part that is easy to bend in the way that the other facing wall of the hollow extruded shape is recessed inside the hollow extruded shape is extruded beforehand. In this case, the easily bendable shape portion is partially bent in the longitudinal direction to partially reduce the interval between the walls facing each other of the hollow extruded shape member, thereby forming an automobile structural member having a desired shape. A method for molding a structural member for an automobile using a hollow extruded profile, which is characterized in that: 2. A hollow extruded shape member is set in a molding die on which a molding surface of a desired automobile structural member is formed, and is pressed by a pressing die such as a pressing machine in a direction in which the interval between the opposing walls is reduced. 2. The method for molding a structural member for an automobile using the hollow extruded profile according to claim 1, wherein the easily bendable shape part is partially deformed in the longitudinal direction of the hollow extruded profile. 3. An easily bendable portion formed on each of the other opposing walls has an outer notch formed along the longitudinal direction at a central portion of the outer surface of each wall and an inner surface of each wall. The method for molding a structural member for an automobile using the hollow extruded profile according to claim 1, comprising two inner notches formed symmetrically with respect to the outer notch. 4. The depth h1 of the outer notch and the depth h2 of the two inner notches satisfy h1 ≧ h2, and with respect to the plate thickness t, h1: 0.3 t or more and less than 0.7 t h2 : 0.2t or more and less than 0.7t is satisfied, The molding method of the structural member for motor vehicles using the hollow extrusion profile of Claim 3 characterized by the above-mentioned. 5. The easily bendable portion formed on each of the other opposing walls is concave with respect to the outer surface of the wall formed along the longitudinal direction at the central portion of each wall and the inner surface of the wall. A curved central bead that is convex with respect to the central bead, and two curved double-sided beads that are convex with respect to the outer surface of the wall and concave with respect to the inner surface of the wall and that are formed symmetrically with respect to the central bead. The method for molding a structural member for an automobile using the hollow extruded profile according to claim 1. 6. The easily bendable portion formed on each of the other opposing walls is concave with respect to the outer surface of the wall formed along the longitudinal direction at the central portion of each wall and the inner surface of the wall. 2. A curved central bead that is convex with respect to the central bead, and a slanting wall portion that is a wall that is continuous with both sides of the central bead and that is slanted so as to be recessed inside the hollow extruded profile. 1. A method of molding a structural member for an automobile using the hollow extruded profile of claim 1. 7. The method for molding an automobile structural member using a hollow extruded profile according to claim 5, wherein one or both of the central bead and the both-side beads are made thicker than other portions. . 8. The structure for automobiles using the hollow extruded profile according to claim 6, wherein the wall thickness of one or both of the bent portion of the central bead and the inclined wall portion is larger than that of the other portion. Method of molding a member. 9. A method of molding a structural member for an automobile body using a hollow extruded profile having a substantially rectangular closed cross section, wherein, of two sets of opposed walls of the hollow extruded profile, one of the opposing walls has a space between them. When forming into a partially different shape in the longitudinal direction, when the other opposite wall of the hollow extruded shape is bent in the hollow interior of the hollow extruded shape to form a bent shape part in advance, After being formed, a pressure is applied to the hollow inner wall surface of the hollow extruded shape member to partially expand the bent shape portion in the longitudinal direction, so that the space between the opposing walls of the hollow extruded shape member is partially increased. A method for molding a structural member for an automobile using a hollow extruded shape, characterized by increasing the number and molding the structural member for an automobile having a desired shape. 10. A structural member for an automobile using a hollow extruded shape member according to claim 9, wherein the hollow inner wall surface of the hollow extruded shape member is partially expanded by hydraulic bulge forming. Molding method.