JP2002331317A - Blanks for body panels - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blank member for an auto body panel capable of preventing cracks caused at the time of press forming as a mid-thickness section having no degeneration section is provided and capable of bettering formability of the blank member for the auto body panel and capable of improving productivity as the panel is formed from a piece of plate. SOLUTION: In the blank member 11 for the auto body panel composed of a thick section 12 and a thin section 13 manufactured by rolling, the blank member for the auto body panel characterized by the feature that a middle thickness section 14 is provided, in which thickness changes in stages or in succession from the thick section 12 to the thin section 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blank for a vehicle body panel.

[0002]

2. Description of the Related Art As a blank material for a vehicle body panel, for example, there is a material disclosed in Japanese Patent Application Laid-Open No. H11-104750 entitled "Press forming method of butt weld plate". According to paragraphs [0015] to [0018] of the publication, the blanks made of butt welded plates are as follows. However, the following is a summary of the original text. First, the thick plate 13, the thin plate 11, and the plate 12 inserted therebetween are welded by laser, respectively, to form one blank material. Then, this blank material is press-formed on a door inner panel of the vehicle body. As described above, in the blank material disclosed in the publication, since the thickness of the inserted plate 12 is set between the thick plate 13 and the thin plate 11, the occurrence of cracks in the thin plate 11 can be suppressed, and the press formability can be improved. Can be improved.

[0003]

However, the blank material of the door inner panel disclosed in the above publication is welded and has a deteriorated portion accompanying the welding. In other words, when a welded blank is used, there is a risk that cracks will occur in the deteriorated portion of the weld during press forming, the degree of plastic working will be small, the degree of freedom in the shape to be formed is narrow, and the blank for body panels will be used. Is difficult to improve. When performing butt welding with a laser, it is necessary to prepare plates 11, 12, and 13 having different plate thicknesses, and to process the end faces (grooves) of these plates with high precision. It is necessary to match each other accurately, which is troublesome, and it is difficult to improve the productivity of blank materials for body panels. Furthermore, there are many types of boards, and handling and management are troublesome.

Accordingly, an object of the present invention is to provide a blank for a vehicle body panel in which formability is improved and productivity is improved.

[0005]

In order to achieve the above object, a first aspect of the present invention is to provide a blank for a vehicle body panel comprising a thick portion and a thin portion manufactured by rolling or cutting, from a thick portion to a thin portion. It is characterized in that it is provided with a middle portion whose thickness changes stepwise or continuously.

[0006] Since the thick portion, the medium portion and the thin portion are formed in order from one sheet by rolling, a deteriorated portion of the weld cannot be formed on the step portions on both sides of the medium portion. Further, since the thickness is changed stepwise by the middle portion, there is no fear that a crack is generated between the thick portion and the thin portion during press molding. in this way,
Since the blank for the vehicle body panel can be extended in accordance with the mold by the middle portion having no deteriorated portion, the formability of the blank for the vehicle body panel is improved. Furthermore, the blank for the vehicle body panel can be formed continuously from a single plate to the inner wall portion, and the productivity of the blank for the vehicle body panel is improved.

In the second aspect, the thickness of the thick portion is defined as t1,
Assuming that the thickness of the thin portion is t2 and the thickness of the middle portion is t3, the thickness t3 is t2 + 0.1 (t1-t2) <t3
<T2 + 0.9 (t1−t2).

When the thickness is less than t2 + 0.1 (t1-t2), the thickness t3 of the middle portion is small, and the difference from the thickness t1 of the thick portion is large. In this case, the stress generated at the boundary between the plate thickness t3 and the plate thickness t1 increases, and it is necessary to consider cracks and wrinkles when forming the vehicle body panel. t2 + 0.9 (t1-
When t2) is exceeded, the thickness t3 of the middle portion is large, and the difference from the thickness t2 of the thin portion is large. In this case, the stress generated at the boundary between the plate thickness t3 and the plate thickness t2 increases, and it is necessary to consider cracks and wrinkles when forming the vehicle body panel. As a result, the plate thickness t3 is t2 + 0.1 (t1-t
2) <t3 <t2 + 0.9 (t1-t2) was set.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a front view (first embodiment) of a body panel blank according to the present invention. A body panel blank 11 has a thick part 12 formed on the left side and a thin part formed on the right side. 13 and a middle portion 14 formed in the center
And consisting of The length of the thick part 12 is L1, and the thickness of the thin part 13 is L1.
Is L2, the length of the middle portion 14 is L3, the thickness of the thick portion 12 is set to t1, and the thickness of the thin portion 13 is t2.
, And the plate thickness of the middle portion 14 was set to t3. The middle part 14 has a first step part 15 formed on the thick part 12 side and a second step part 16 formed on the thin part 13 side. L
4 is the length of the first step 15 and L5 is the length of the second step 16.

[0010] The thickness t3 of the middle portion 14 is t1>t3> t
2, which is a dimension for changing the thickness step by step, specifically, t2 + 0.1 (t1-t2) <t3 <t2 +
0.9 (t1-t2) was set. As an example, the thickness t1 of the thick portion 12 is set to 3.0 mm, and the thickness t1 of the thin portion 13 is set.
When 2 is set to 1.8 mm, for example, the thickness t3 of the medium thickness portion 14 is 2.4 mm, but the thickness t3 may be other than this, and is set in the range of 1.92 mm to 2.88 mm. do it.

Below t2 + 0.1 (t1-t2), the thickness t3 of the middle portion 14 is small and the difference from the thickness t1 of the thick portion 12 is large. In this case, the stress generated at the boundary between the plate thickness t3 and the plate thickness t1 increases, and it is necessary to consider cracks and wrinkles when forming the vehicle body panel. t2 + 0.9
If (t1−t2) is exceeded, the thickness t3 of the middle portion 14 is large, and the difference from the thickness t2 of the thin portion 13 is large. In this case, the stress generated at the boundary between the plate thickness t3 and the plate thickness t2 increases, and it is necessary to consider cracks and wrinkles when forming the vehicle body panel. As a result, the plate thickness t3 is t2 + 0.
1 (t1-t2) <t3 <t2 + 0.9 (t1-t2)
Set to.

The first step portion 15 is a portion formed in an arc shape, and the radius of the arc is set to R. The second step portion 16 was the same as the first step portion 15, and the radius of the arc was set to R.

Next, a description will be given of a method of manufacturing the blank 11 for a vehicle body panel according to the present invention. Here, a manufacturing method by rolling will be described. FIGS. 2 (a) to 2 (c) are first explanatory views (first embodiment) of the method for manufacturing a body panel blank according to the present invention.
(Embodiment), which is a schematic diagram of rolling.

(A): First, the plate 21 is passed through a rolling mill 22. Specifically, the thickness of the plate 21 is t1, and one end 23 of the plate 21 is connected to the upper and lower work rolls 2 of the rolling mill 22.
It is transported between 4, 25 as shown by the arrow. Under the preset rolling conditions, for example, the radii of the upper and lower work rolls 24 and 25 are set to R, and the roll gap between the upper and lower work rolls 24 and 25 is set to G1. At that time, the roll gap G
The measurement of 1 is performed by, for example, a roll gap detection unit 26 provided on the upper work roll 24. The non-rolled part of the plate 21 corresponds to the thick part 12.

(B): Subsequently, a plate thickness t3 is formed on the plate material 21. One end 23 of the plate material 21 is bitten between the upper and lower work rolls 24 and 25, and is rolled to obtain a distance L6.
(L6 = L1 + L4) and upper and lower work rolls 24, 25
Is temporarily stopped, thereby completing the plate thickness t3 of the intermediate portion 14 and, at the same time, completing the first step portion 15 having the radius R. At this time, the other end 25 of the plate 21 is detected by the first distance detecting means 27, and the distance L6 is measured.
Stop the rotation of.

(C): Subsequently, the medium thickness portion 14 is formed to a predetermined length. Specifically, upper and lower work rolls 2
The upper and lower work rolls 24 and 25 are stopped at a distance L7 to determine the length L3 of the medium thickness portion 14. At this time, the other end 25 of the plate 21 is detected by the second distance detecting means 28, and the distance L7 is measured. At the same time, the rotation of the upper and lower work rolls 24, 25 is stopped by the signal of the second distance detecting means 28. .

FIGS. 3A to 3C are second explanatory views (first embodiment) of the method for producing a body panel blank according to the present invention, and are schematic views of rolling. (A): Subsequently, the upper work roll 24 is pressed as shown by the arrow to change the roll gap to G2. By setting the roll gap to G2, the intermediate portion 14 is completed, and the second step portion 16 having the radius R is also completed.

(B): The upper and lower work rolls 24, 25 of the roll gap G2 are rotated as shown by the arrows,
Through the remainder of 4, a thin portion 13 is formed, and the material is rolled to a plate thickness t2.

In the step of forming the medium and thin portions 14 and 13, the medium portion 14 is formed on the plate material 21, and then the remaining portion of the medium portion 14 is rolled to form the thin portion 13.
The plate material 21 is plastically deformed in order from a thick state to a thin state, and no irregularities are formed on the second step portion 16 at the edge of the intermediate portion 14, so that the radius dimension R can be ensured and the radius dimension can be ensured. No effort is required for R processing.

(C): Finally, the rolling is completed at the roll gap G2, and the thin portion 13 is completed, and the body panel blank 31 is completed. The body panel blank 31 is equivalent to the body panel blank 11 (see FIG. 1).

FIG. 4 is a perspective view (first embodiment) of a blank material for a vehicle body panel according to the present invention, in which the plate thicknesses t1 and t2 are changed stepwise from the thick portion 12 to the thin portion 13. 5 shows the vehicle body panel blank 11 in which the middle portion 14 of t3 is formed. W indicates the width.

As described above, since the thick portion 12 is rolled and the middle portion 14 is formed between the thick portion 12 and the thin portion 13, the middle portion 1 is formed.
In providing 4, the first step portion 15 and the second step portion 16 cannot have a deteriorated portion of welding. Also, the middle portion 1 whose thickness changes stepwise from the thick portion 12 to the thin portion 13.
4, the large stress concentration does not occur between the thick portion 12 and the thin portion 13 even when the blank material 11 for a vehicle body panel is plastically processed. That is, since the hollow portion 14 having no deteriorated portion is provided, there is no fear that cracks will be generated even if the blank body 11 for the vehicle body panel is plastically processed by press forming in a later process. Can be improved.

In the blank material 11 for a vehicle body panel,
The first step portion 15 and the second step portion 16 are provided with the radius dimension R, respectively, while forming the middle portion 14, so that the first step
-Stress concentration hardly occurs in the second step portions 15 and 16, and there is no fear that a crack is formed between the thick portion 12 and the thin portion 13 during the press forming in a later step, and it is more suitable for a body panel. The formability of the blank 11 can be improved.

Further, the blank material 11 for the body panel is
The intermediate portion 14 is formed by rolling from the thick portion 12 to the thin portion 13 and can be continuously formed from one plate, so that the productivity of the body panel blank 11 can be improved. .

In addition, since the thick portion 12 is rolled to form the middle portion 14 between the thin portion 13 and the rolling portion, the rolled portion is annealed at a desired temperature condition (not shown) after rolling. The mechanical properties of the intermediate portion 14 can be adjusted, and desired moldability can be obtained without worrying about cracking.

Next, an example of press forming of the body panel blank 11 will be briefly described. FIGS. 5A and 5B are explanatory views (first embodiment) of press-forming the blank material for a vehicle body panel according to the present invention, and show a door panel as an example of the vehicle body panel. (A): After blank body 11 for a vehicle body panel (see FIG. 4) is formed into a predetermined shape by a mold (not shown) in advance, the mold 33 (upper mold 33a, lower mold 33) of press machine 32 shown in FIG. Mold 33
Finishing in step b), the door panel 34 is completed. As described above, even when the blank 11 for the vehicle body panel is plastically deformed by press forming, no crack is generated in the blank 11 for the vehicle body panel.

(B): The door panel 34 is taken out of the mold and one cycle of press molding is completed. Thereafter, the door panel 34 is transported to a downstream process. As described above, since the body panel blank 11 is excellent in formability, the degree of freedom of the shapes of the door panel and the body panel can be increased, and the range of use can be expanded.

Next, a second embodiment of the body panel blank according to the present invention will be described. FIG. 6 is a diagram of a second embodiment. The same components as those of the embodiment shown in FIG. The vehicle body panel blank 11B is characterized in that it has an inclined portion 41 as an intermediate portion whose thickness continuously changes from the thick portion 12 to the thin portion 13. Specifically, the vehicle body blank 11B is , Thick portion 12, thin portion 13, and inclined portion 41
The length of the thick portion 12 is L1, and the thickness of the thin portion 13
Is L2, the length of the inclined portion 41 is L8, the thickness of the thick portion 12 is set to t1, and the thickness of the thin portion 13 is t2.
And the inclination angle of the inclined portion 41 is set to θ.

The vehicle body panel blank 11B can exhibit the same effect as the vehicle body panel blank 11 described above. Further, in the body panel blank 11B, the inclined portion 4 is provided between the thick portion 12 and the thin portion 13.
Since 1 is provided, stress concentration can be further avoided during plastic working, and the formability of the body panel blank can be further improved.

Next, a method of manufacturing the body panel blank 11B according to the present invention will be described. FIGS. 7A to 7C are explanatory views (second embodiment) of a method for manufacturing a blank material for a vehicle body panel according to the present invention. In addition, FIG.
The description of the same steps as the manufacturing steps shown in (b) is omitted, and the following manufacturing steps will be described.

(A): The plate 21 is rolled by the upper and lower work rolls 24 and 25, temporarily stopped at a distance L6 to form a plate thickness t3 of the middle portion 14, and then the inclined portion 41 (see FIG. 6) is formed. Form. In detail, while reducing the roll gap G1 of the upper and lower work rolls 24 and 25 as shown by a two-dot chain line,
The reverse rotation of the upper and lower work rolls 24 and 25 is started.

(B): While the upper and lower work rolls 24 and 25 are rotated in reverse as indicated by the arrows, the roll gap is reduced as indicated by the arrows, so that the formation of the inclined portion 41 is continued.

(C): The rotation of the upper and lower work rolls 24 and 25 and the reduction of the roll gap are synchronized to complete the formation of the inclined portion 41 having the inclination angle θ, and the roll gap reaches G2. Subsequently, the middle portion 14 is rolled at the roll gap G2 to form the thin portion 13 as shown by the two-dot chain line, and the vehicle body panel blank 11B is completed. Thereafter, the vehicle body panel formed using the vehicle body panel blank 11B may be the door panel 34 of FIG. 5 and is optional.

Next, a third embodiment of the vehicle body panel blank according to the present invention will be described. FIG. 8 is a diagram of a third embodiment, and the same components as those of the embodiment shown in FIG. 1 are denoted by the same reference numerals and description thereof will be omitted. The vehicle body panel blank 11C is characterized in that an intermediate wall 44 having a plate thickness t4 is formed integrally on the right side of the thin wall 43, and in more detail, the vehicle panel blank 11C comprises a thick wall 12 and It is composed of an intermediate portion 14, a thin portion 43, and an intermediate portion 44. The length of the thin portion 43 is L9, and the length of the intermediate portion 44 is L10.
And the plate thickness t4 of the intermediate portion 44 is t3>t4> t2
Set to.

The body panel blank 11C can exhibit the same effect as the body panel blank 11 described above. Further, by forming the body panel blank 11C into a body panel, the weight of the body panel can be reduced while improving the strength of the body panel.

Next, a method of manufacturing the blank 11C for a vehicle body panel according to the present invention will be described. FIGS. 9A to 9C are explanatory views (third embodiment) of a method for manufacturing a body panel blank according to the present invention. 2 and 3 described above.
The description of the same steps as the manufacturing steps shown in (a) and (b) will be omitted, and the following manufacturing steps will be described.

(A): The remaining portion of the middle portion 14 is rolled by the upper and lower work rolls 24 and 25 of the roll gap G2, and the formation of the thin portion 43 is continued. (B): Simultaneously with the completion of the thin portion 43, the rotation of the upper and lower work rolls 24, 25 is temporarily stopped, the roll gap is increased as indicated by the arrow, and the roll gap is set to G3.
, And the upper and lower work rolls 24 and 25 are rotated again to start the remaining rolling of the medium thickness portion 14.

(C): Finally, the formation of the intermediate portion 44 is completed, and the blank 11C for the vehicle body panel is completed. In the step of forming the intermediate portion 44, the thin portion 4
3 to the intermediate portion 44, so that the second step 16
In addition, unevenness is not formed at the boundary 44a of the thin portion 43, and dimensional accuracy can be ensured. As a result, there is no concern that the second step portion 16 and the boundary 44a may be the starting points of cracks during the press forming in the subsequent step, and the blank 1
The moldability of 1C can be improved.

The manufacturing method described in the embodiment of the present invention is an example, and the manufacturing method is arbitrary. For example, FIG.
In the manufacturing method shown in FIG. 3, the middle portion 14 is rolled and then the thin portion 13 is formed. On the contrary, the thin portion 13 is completed first, and the middle portion 14 is formed next to the thin portion 13. Is also possible. The rolling mill 22 is an example, and the type of the rolling mill is arbitrary. Blank material 1 for car body panel by rolling mill 22
Although 1 was formed, it is also possible to manufacture by cutting. The plate thickness is not limited to three types of plate thicknesses t1, t2, and t3. The door panel 34 is an example of a door panel.

[0040]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, in the blank material for a vehicle body panel composed of a thick part and a thin part manufactured by rolling or cutting, a middle part whose thickness changes stepwise or continuously from the thick part to the thin part is used. Since the thick portion, the middle portion, and the thin portion can be sequentially formed from a single plate, a deteriorated portion of welding cannot be formed at the step portions on both sides of the middle portion. Also,
The middle portion can prevent stress concentration at the time of press forming. That is, since the stress concentration is prevented and the mechanical properties are prevented from being reduced by the middle portion having no deteriorated portion, cracks occur between the thick portion and the thin portion even when plastic deformation is performed by press molding. Absent. Therefore, the formability of the body panel blank can be improved.

The thick part, medium part and thin part are rolled to 1 mm.
Since it is formed from two sheets, it can be formed continuously, and it does not take much time to form thick, medium, and thin parts.
The productivity of the blank material for vehicle body panels can be improved.

According to a second aspect, the thickness of the thick portion is t1,
Assuming that the thickness of the thin portion is t2 and the thickness of the middle portion is t3, the thickness t3 is t2 + 0.1 (t1-t2) <t3
<T2 + 0.9 (t1-t2) is set. t2 + 0.
When the thickness is less than 1 (t1−t2), the thickness t3 of the middle portion is small,
The difference from the plate thickness t1 of the thick portion becomes large. In this case, the stress generated at the boundary between the plate thickness t3 and the plate thickness t1 increases,
When molding body panels, it is necessary to consider cracks and wrinkles. If t2 + 0.9 (t1-t2) is exceeded, the thickness t3 of the middle portion is large, and the difference from the thickness t2 of the thin portion is large. In this case, the stress generated at the boundary between the plate thickness t3 and the plate thickness t2 increases, and it is necessary to consider cracks and wrinkles when forming the vehicle body panel. As a result, the thickness t3
To t2 + 0.1 (t1-t2) <t3 <t2 + 0.9
By setting (t1-t2), the plate thickness t1 and the plate thickness t2
Between the sheet thickness t1 and the sheet thickness t2, and the occurrence of cracks and wrinkles can be prevented.

[Brief description of the drawings]

FIG. 1 is a front view of a body panel blank according to the present invention (first embodiment).

FIG. 2 is a first explanatory view of the method for producing a body panel blank according to the present invention (first embodiment);

FIG. 3 is a second explanatory view (first embodiment) of the method for producing a body panel blank according to the present invention.

FIG. 4 is a perspective view of a body panel blank according to the present invention (first embodiment).

FIG. 5 is an explanatory view of a press forming of a blank material for a vehicle body panel according to the present invention (first embodiment).

FIG. 6 is a view of a second embodiment.

FIG. 7 is an explanatory view of a method of manufacturing a blank material for a vehicle body panel according to the present invention (second embodiment).

FIG. 8 is a view of a third embodiment.

FIG. 9 is an explanatory view of a method of manufacturing a blank material for a vehicle body panel according to the present invention (third embodiment).

[Explanation of symbols]

11, 11B, 11C ... blank material for body panels, 12
... thick part, 13 ... thin part, 14 ... medium part.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masashin Numano 1-10-1, Shinsayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd.

Claims (2)

[Claims] 1. A car body panel blank comprising a thick portion and a thin portion produced by rolling or cutting, wherein the thickness of the medium portion changes stepwise or continuously from the thick portion to the thin portion. A blank material for a vehicle body panel, comprising: 2. When the thickness of the thick part is t1, the thickness of the thin part is t2, and the thickness of the middle part is t3, the thickness t3 is t2 + 0.1 (t1-t2). ) <T3 <t2 +
2. The blank according to claim 1, wherein the blank is set to 0.9 (t1-t2).