JP2001321842A - Hydroforming, hydroforming method of the forming and vehicle member using hydroforming - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydroformed product for improving the quality of a forming having an external section gradually and variously changing its outer diameter. SOLUTION: The hydroformed part is obtained by a method that a tube stock 18, which is roughly conical shape obtained by rolling a steel plate member 18a of roughly trapezoidal shape to trace an external shape change of a product, is subjected to hydroforming. Thus, in the case of the product 14 to have the external section changing gradually and variously its external diameter, the high quality product 14 with a tube expanding rate falling in a restricted range is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydroformed product having an outer portion whose outer diameter gradually changes in size, a hydroforming method of the same, and a vehicle body member using the hydroformed product.

[0002]

2. Description of the Related Art The body (body) of an automobile (vehicle) is required to have high rigidity in order to ensure the safety of collision from the side of the body.

Therefore, in a center pillar portion forming a skeleton of a body side portion, conventionally, an inner panel 2 is assembled to a side outer panel 1 as shown in FIGS. 6 (a) and 6 (b).
The center pillar reinforce 3 is assembled to this structure. In addition, reinforcement is added to places requiring further reinforcement, in this case, four types of reinforcements 4a to 4d are additionally reinforced.

[0004] By the way, in such a structure in which many reinforcements are assembled and reinforced, the assembly accuracy tends to vary. In addition, since various reinforcements are assembled by spot welding (arc welding) performed at predetermined intervals, it is difficult to secure required rigidity.

[0005] Therefore, it has been considered to secure the rigidity to replace the reinforcements with only one thin reinforcement having a closed cross section.

Specifically, it is conceivable to use a member having a closed cross-sectional shape formed by hydroform molding as disclosed in JP-A-8-337182 and JP-A-8-192238 to form a reinforcement member. Can be

In the hydroform molding, a base tube having a predetermined diameter is placed in a mold having a final shape formed by an upper die and a lower die, and water (pressurized liquid) is pressed into the raw tube and pressurized from the inside. This is a molding method in which a product with a closed cross-sectional shape (mouth shape) that conforms to the shape of the mold surface is formed by expanding the tube (expanding the tube) and fitting the expanded tube into the upper and lower mold surfaces. .

The reinforcement member formed by the hydroform molding not only has a closed cross-sectional shape formed by a continuous peripheral wall, but also has a thin plate thickness due to work hardening caused by extension of the peripheral wall of the raw tube. High rigidity equivalent to a plurality of types of reinforcements can be obtained with one component.
Moreover, since there is almost no springback, the product accuracy is good and the assembly accuracy is good.

[0009]

In the hydroform molding, it is required to uniformly inflate each part of the raw tube to the product shape so that the material is not excessively strained and the product is not broken. (Expansion). In particular, in order to obtain a good product by hydroform molding, it is usually required that the pipe expansion ratio be within a certain range (for example, within 0 to 25%).

The center pillar portion of the vehicle body has a small diameter at the upper end, a large diameter at the lower end, and an elongated shape in which the outer peripheral shape (cross section) gradually changes from the upper end to the lower end.

For this reason, when forming the reinforcement to be assembled to the center pillar portion by hydroforming, it is necessary to select a raw tube based on a portion having a small diameter in the final shape, and subject the tube to hydroforming. Become.

However, since the size of each portion of the reinforcement, which is a product shape, is different, each portion of a raw tube having a constant cross section expands at a different expansion ratio. In particular, the difference in the circumferential length between the upper end portion having the small diameter portion and the lower end portion having the large diameter portion is remarkable, and the large diameter side is twice as large as the small diameter side, and even more. For this reason, the expansion ratio is not within the normal range, and the molded product of the hydroform molding simply has an external shape such as a center pillar portion whose outer diameter gradually changes in the entire length direction. No product was obtained.

The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide a hydroform molded product capable of improving the quality of a product having an outer portion whose outer diameter gradually changes in size. To provide.

It is a second object of the present invention to provide a method for forming a hydroform in which a product whose outer diameter gradually changes in size can be maintained by a hydroform molding while keeping the expansion ratio within a certain range. .

It is a third object of the present invention to provide a vehicle body member capable of improving rigidity strength by using characteristics of a hydroformed product.

[0016]

In order to achieve the first object, a hydroformed article according to claim 1 is provided.
The outer diameter gradually changes to a product made by applying a hydroform molding to a substantially conical base tube that is wound on a substantially trapezoidal plate member and joined on both sides to conform to the outer shape of the product Even if the product has an external shape, a high-quality product with an expansion ratio within a limited range can be obtained.

In order to achieve the second object, a second aspect is provided.
The hydroform molding method according to the above, when forming a hydroform molded product having an outer portion whose outer diameter gradually changes in size by hydroform molding, winding a substantially trapezoidal plate member and joining both side portions thereof After forming a substantially conical base tube following the change in the outer shape of the hydroform molded product, the base tube is subjected to hydroform molding to form a product shape.

In order to achieve the third object, a third aspect is provided.
The vehicle body member according to the above, the cross-sectional shape is substantially U-shaped, and the cross-sectional size gradually changes in the length direction of the elongated panel member, housed inside the panel member and attached to the panel member Of the panel structure combined with the reinforcing member, the outer shape of the reinforcing member was changed so as to follow the outer shape of the panel member formed by winding a substantially trapezoidal plate member and joining both sides. A substantially conical elemental tube was used, and the elemental tube was formed into a closed cross-sectional shape along the inner wall surface of the panel member by hydroforming.

At this time, a contact surface for abutting the inner wall surface of the panel member to position the reinforcement member at a fixed position may be formed on a part of the outer surface of the reinforcement member by using hydroforming. In this way, the positioning of both members can be performed reliably.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to one embodiment shown in FIGS.

FIG. 1 is an exploded view of the structure of a center pillar portion 11 provided on a vehicle body side of an automobile (vehicle). The center pillar portion 11 has a small outer diameter on the upper end side assembled on the roof rail side, a large outer diameter on the lower end side assembled on the side sill side, and the outer peripheral shape (cross section) gradually changes from the upper end side to the lower end side. It is a skeletal portion of a slender body that extends vertically.

In the figure, reference numeral 12 denotes a side outer panel of the center pillar portion 11 which is arranged on the outermost side of the vehicle. The side outer panel 12 has a hat-shaped cross section whose opening faces the interior of the vehicle. A reinforcing structure 13 (corresponding to a vehicle body member of the present application) is attached to the inside of the side outer panel 12 (a portion surrounded by a hat-shaped cross section) to increase rigidity (reinforcement).

The reinforcing structure 13 is composed of one part as shown in FIG.
A reinforcement member 14 (corresponding to the hydroform molded product of the present application) made of hydroform that provides rigidity to replace the inner panel 2 and reinforcements 4a to 4d in the center pillar reinforcement 3 in FIG.
(Corresponding to the panel member of the present application), and a structure for assembling in the side outer panel 12 is employed.

For details, see Center Pillar Reinforce 3
The cross-sectional shape is formed of a panel component having a substantially U-shaped cross-section, specifically, a substantially hat-shaped cross-sectional shape. The outer shape has a small diameter at the upper end and a large diameter at the lower end, similar to the side outer panel 12. The outer peripheral shape (cross section) has an elongated shape that gradually changes from the upper end side to the lower end side. At the upper end side of the inner wall surface formed by the substantially hat-shaped cross section, there is an opening that expands after constriction, and there is a part where the opening temporarily narrows in the middle of the lower stage. In the figure, 3x indicates a constricted portion on the upper end side, 3y indicates an enlarged portion immediately above the constricted portion 3x, and 3z indicates a narrowed portion on the lower side.

The reinforcement member 14 has a single base tube 18.
Is subjected to hydroform molding to form a closed cross-section conforming to the inner wall surface of the center pillar reinforce 3, specifically, from the enlarged portion 3y immediately above the constricted portion 3x to the narrowed portion 3
It is formed from a rectangular tube-shaped product that densely fills the inside of the inner wall up to z.

In this case, the outer peripheral shape of each part of the reinforcement member 14 gradually changes in size, and the outer diameter of the upper part is smaller than that of the other part, especially the lower part of the large diameter part 15a. The small diameter portion 15
In the case where the base tube 18 is selected on the basis of b and subjected to hydroform molding (forming in which the inside tube is expanded by pressurizing the inside to conform to the mold surface), the expansion ratio between the small diameter side and the large diameter side is excellent. It does not fall within the range that can be performed (for example, 0 to 25%).

Therefore, a device for obtaining a good product has been devised. This ingenuity is achieved by the reinforcement member 14 as a product.
However, the product is formed from a base tube 18 whose outer peripheral shape is changed in accordance with a change in the outer shape of the center pillar reinforce 3 as shown in FIG. 2 (b).

More specifically, as shown in FIG. 2 (a), the raw tube 18 is formed by winding a steel plate member 18a formed in, for example, a chevron shape having a short upper base and a long lower base, that is, a substantially trapezoidal shape. A structure formed into a substantially conical cylindrical body is used. The base tube 18 is formed in a conical shape having a slope whose outer shape changes continuously in response to a change in the outer shape of the center pillar reinforce 3.

By using the raw tube 18, the product formed by hydroforming, ie, the reinforcement member 14, has one end having a small diameter, the other end having a large diameter, and a gradually outer peripheral shape between both ends. Each of the parts where the diameter changes changes becomes a molded product whose tube length is continuously expanded at the same ratio.

As a result, the entire reinforcement member 14 including the large diameter portion 15a, the small diameter portion 15b, and the space between the two are separated from the base tube 18 by a pipe expansion ratio within a restricted range (for example, 0).
(Within the range of ２５25%), so that it is a product of good quality without breakage or excessive stress burden.

On the other hand, the reinforcement member 14 is formed with a structure for positioning with respect to the center pillar reinforcement member 3. As shown in FIG. 1 and FIG. 2 (f), this is a structure in which a part of the outer surface of the reinforcement member 14 is formed with a contact surface which contacts the inner wall surface of the center pillar reinforcement 3 by using hydroforming. It is. More specifically, the small-diameter end of the reinforcement member 14 is closely fitted to the enlarged portion 3y immediately above the constricted portion 3x of the center pillar reinforcement 3 as a contact surface for positioning the reinforcement member 14 in the longitudinal direction. A round fan-shaped portion 14a is formed. Also, at the end of the reinforcement member 14 on the large diameter side,
Similarly, a narrow portion 14b that closely fits the narrowing portion 3z is formed. Further, on the back surface (surface in the depth direction) of the reinforcement member 14, as an abutting surface for positioning the reinforcement member 14 in the depth direction, for example, the inner bottom surface of the center pillar reinforcement member 14 is provided at the upper and lower two-stage portions. A corresponding projection 14c is formed. In addition, the reinforcement member 1
The positioning in the width direction of 4 is performed by the walls themselves on both sides in the width direction.

On the other hand, the method of forming the reinforcement member 14 is devised so that the forming is performed at a pipe expansion ratio within a restricted range. The hydroform molding method uses a substantially conical base tube 18 as shown in FIGS. 2A to 2E when the reinforcement member 14 (hydroform molded product) is molded. .

That is, the raw tube 18 is, for example, shown in FIG.
As shown in FIG. 2A, a substantially trapezoidal steel plate member 18a having a short upper part and a long lower part is prepared, and as shown in FIG. , The two sides are butted together, and the sides are joined by welding to form a substantially conical pipe structure. At this time, the conical shape of the base tube 18 has a hypotenuse that is previously inclined at an angle that follows the external shape that gradually changes. First, as shown in FIG. 2C, preforming is performed on the raw tube 18 so that the entire length bends in the shape of an arc so that the entire length bends the entire length of the product. In this case,
Pressing may be performed on the homogenous tube 18 so that the joint is not visible. Subsequently, as shown in FIG.
1 is placed in a mold of a final shape (a space shape from an enlarged portion 3y immediately above the constricted portion 3x of the center pillar reinforce to a narrowed portion 3z: product shape) formed by the lower mold 22 and the lower mold 23. Then, the hydroform molding machine 21 is operated, and as shown in FIGS.
Water (pressurized liquid) is pressurized into the inside, and the element tube 18 is expanded (expanded) by pressurization from the inside, and the expanded element tube 18 is adapted to the upper and lower molds 22 and 23.

At this time, the outer peripheral shape of each part of the raw tube 18 is
Since the final shape is a substantially conical shape following the change in the outer shape of the product shape (here, the shape following the inner wall surface of the center pillar reinforce 3), each part of the raw tube 18 is , A pipe expansion ratio within a certain range (for example, 0 to 25)
% Of the product).

As a result, a product having an outer portion whose outer diameter gradually changes as shown in FIG. 2 (f), that is, a reinforcement member 14 having a rectangular closed cross section whose outer diameter changes greatly, Good molded without breaking.

Moreover, since the pipe 18 is a substantially conical pipe member formed by winding a substantially trapezoidal steel plate member, it can be formed easily using existing equipment at no cost, and can be manufactured at low cost and quality. Excellent products can be obtained.

Such a reinforcement member 14 is shown in FIG.
As shown in FIGS. 4A and 4B and FIGS. 4A and 4B, it is combined with the center pillar reinforce 3.

More specifically, the reinforcement member 14 is formed in a groove space (a pair of side surfaces and a bottom surface between both side surfaces) from the upper stage (immediately above the constricted portion 3x) to the lower stage (narrowing portion 3y) in the center pillar reinforcement 3. Formed in a U-shaped groove). At this time, the fan-shaped portion 14a
The narrow portion 14b fits into the narrowing portion 3y and abuts against the narrowing portion 3y, and the upper and lower two protruding portions 14c abut against the wall surface forming the bottom surface of the groove space. . Of course, the left and right side walls on both sides in the width direction abut against the side walls forming the side surfaces of the groove space. Thus, the reinforcement member 14 is restricted so as not to move in the vertical direction, the width direction, and the depth direction as long as the reinforcement member 14 is fitted to the center pillar reinforcement 3, and is reliably positioned at a predetermined position (fixed position). . The reinforcement member 14 is joined to the center pillar reinforcement 3 by arc welding to form a reinforcing structure 13 suitable for reinforcing the center pillar portion 11. In FIG.
Indicates the welded portion.

The reinforcing structure 13 is welded to the side outer panel 12 by using the spot welding assembly process in the vehicle body assembly line. More specifically, since the center pillar reinforce 3 has the same structure as before, that is, a hat-type structure having flange portions 3a, 3a on both sides, the reinforce 3 is used as a sub-assembly part. 5A, the U-shaped portion of the center pillar reinforcement 3 is fitted into the U-shaped portion of the side outer panel 12 as shown in FIG. Flanges 3a on both sides of reinforcement 3
With the flange portions 12 on both sides of the side-out panel 12.
After that, the reinforcing structures 13 are assembled to the side outer panel 12 by spot welding the flange portions to each other as shown in FIG.
In FIG. 5B, reference numeral 25 denotes the welded portion,
Indicates a flange trim to be assembled to the joined flange portions 3a and 12a.

Thus, the rigidity of the center pillar portion 11, which is the frame member of the vehicle body, can be increased by using a hydroform molded product having excellent rigidity and assembly accuracy.

It should be noted that the present invention is not limited to the above-described embodiment, and may be implemented with various modifications without departing from the gist of the present invention. For example, in the embodiment, an example was given in which a hydroform molded product was used for the center pillar portion serving as a frame member of the vehicle body. However, the invention is not limited to this, and other frame members such as side frames and side sills and other body members are included. May be used. Of course, the hydroform molded product may be directly assembled inside an outer panel member such as a U-shaped or hat-shaped side outer panel without using a sub-assembled part such as a U-shaped or hat-shaped center pillar reinforce, Further, the skeleton member of the vehicle body may be constituted only by the hydroform molded product itself.
In addition, in one embodiment, in order to easily explain the hydroform molding, an example in which the inside of the raw tube is simply pressurized is given, but the present invention is not limited to this. Then, the base tube may be expanded (expanded).

[0042]

As described above, according to the first aspect of the present invention, it is possible to obtain a high-quality product even if it is difficult to form a hydroform such that the outer diameter gradually changes. .

According to the second aspect of the present invention, since the hydroform molding is performed using the substantially conical raw tube, even if the outer diameter of the product gradually changes, the expansion ratio is limited within a certain restricted range. And high quality molding can be promised. Moreover, the raw pipe uses existing equipment,
It can be easily formed, and a low-cost and high-quality product can be obtained.

According to the third aspect of the present invention, it is possible to realize a vehicle body member having high rigidity by utilizing the unique characteristics of the hydroform molded product.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a reinforcement member formed of a hydroform molded product according to an embodiment of the present invention, together with a center pillar portion of a vehicle to which the member is assembled.

FIG. 2 is a view for explaining a step in which the reinforcement member is formed by hydroforming.

FIG. 3 is a view for explaining a sub-assembly component in which a reinforcement formed of a hydroform molded product and a sub-assembly component are assembled.

4A is a cross-sectional view of the sub-assembly component taken along line AA in FIG. 3A. (B) Sectional drawing of the sub-assembly component along the BB line in FIG.3 (b).

FIG. 5 is a sectional view for explaining until the sub-assembly component is assembled with an outer panel member.

FIG. 6A is an exploded perspective view illustrating a structure of a center pillar portion of a conventional vehicle. (B) A plan sectional view showing the structure of the center pillar portion assembled.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... Center pillar reinforcement (panel member) 11 ... Center pillar part 12 ... Side outer panel (outer panel member) 13 ... Reinforcement structure (vehicle member) 14 ... Reinforce member (hydroform molded product) 18a ... Steel plate member (plate) 18) Raw tube 21: Hydroform molding machine.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akinobu Iwao 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Naoki Yamada 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation F term (reference) 3D003 AA01 BB01 CA17 CA18 CA34

Claims (3)

[Claims] 1. A hydroform molded product formed from a base tube by hydroform molding into a product having an outer portion whose outer diameter gradually changes in size, wherein the product is a substantially trapezoidal plate member. A hydroformed molded article obtained by subjecting a substantially conical elemental tube which conforms to the outer shape of the product to a winding process to form a substantially conical pipe by winding the two sides together. 2. When forming a hydroform molded article having an outer portion whose outer diameter changes gradually by hydroform molding, a substantially trapezoidal plate member is wound and both side portions are joined to form the hydroform molded product. A method of forming a hydroform, comprising: forming a substantially conical base tube following a change in the outer shape of a formed product; and performing the hydroform forming on the base tube to form a product shape. 3. An elongated panel member having a substantially U-shaped cross-section and a cross-sectional size gradually increasing and decreasing in the entire length direction, and a phosphorus accommodated inside the panel member and attached to the panel member. A force member, wherein the reinforcement member has a substantially conical shape in which the outer shape is changed so as to follow the outer shape change of the panel member by winding a substantially trapezoidal plate member and joining both sides. A body member formed by subjecting a base tube to hydroform molding to form a closed cross-sectional shape along an inner wall surface of the panel member.