JPH09308921A - Press forming method of aluminum alloy plate and pressed part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a press forming method for reducing wrinkles which are generated on the oblique standing wall part of a curved corner part in a drawn article of an Al-alloy plate consisting of a straight side part and curved corner part and having an oblique standing wall part in the depth direction. SOLUTION: This method is the press forming method of the Alplate of a drawn article consisting of the straight side part and curved corner part and having the oblique standing wall part in the depth direction, by taken the ratio Fc/Fs of the initial flange length Fc corresponding to the middle of the curved corner part to the initial flange length Fs corresponding to the straight side as >=0.8 and taking the ratio Lc/Ls of the shock line length Lc in the middle of the curved corner part to the shock line length Ls in the straight side part as <=0.9, the wrinkles generated on the oblique standing wall part of the curved corner of the pressed part are reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-formed product using an Al or Al alloy plate and having straight sides and curved corners, in which the standing wall is inclined with respect to the flange. For example, the present invention relates to a method for press-molding an Al or Al alloy plate and a press-molded product for reducing wrinkles that occur in an inclined standing wall portion of a curved corner portion of an automobile body molded product. In the present specification, A
The term 1 alloy plate shall include both Al plates and Al alloy plates.

[0002]

2. Description of the Related Art A press forming method for obtaining a formed product in which a standing wall portion in the depth direction is inclined with respect to a flange portion by drawing an Al alloy plate is, for example, as shown in FIG. Using a forming machine equipped with a punch 2 having a smaller bottom size, the flange portion 8 of the blank 3 of the Al alloy plate is held by the die 1 and the wrinkle retainer 4, and the punch 2 is moved to perform drawing processing. . Therefore, the obtained molded product is one in which the standing wall portion, which is the side wall rising up with respect to the flange portion 8 in close contact with the die surface, is inclined from the vertical direction.

FIG. 2 is a partial perspective view of a draw-formed product 5 having straight sides and curved corners formed as described above, and FIG. 3 is a cross-sectional view taken along the I plane of FIG. In FIGS. 2 and 3, 7 is a curved corner portion, 71 is an inclined standing wall portion thereof, 6 is a straight side portion, 61 is an inclined standing wall portion thereof, 81 is a flange portion of a molded product, H is a depth of the molded product, Lc. Is the shock line length at the center of the inclined standing wall of the curved corner,
Ls is a shock line length in the inclined standing wall portion on the straight side portion. By the way, in the molded product 5 having the straight side portion 6 and the curved corner portion 7 shown in FIG. 2, when the standing wall portion in the depth direction of the molded product is inclined with respect to the flange portion, the inclined standing wall of the curved corner portion. The part 71 is contracted and deformed with the inflow of the material of the flange part 8, and plastic buckling due to the compressive stress due to the contraction occurs, that is, a phenomenon called a body wrinkle 9 occurs. In order to deteriorate the appearance quality of the body wrinkle 9, various methods are used to suppress or reduce the body wrinkle during press molding.

As a concrete method, there are measures such as increasing the wrinkle holding force and providing a bead on the flange portion to increase the tension applied to the inclined standing wall portion. However, a press-formed product of an actual Al alloy plate, For example, in the case of a press-formed product made of an Al alloy plate having a complicated shape having a straight side portion and a curved corner portion such as an automobile part, it cannot be said that a study on a concrete measure is sufficient.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to press-form an Al alloy plate to obtain a molded product having a straight side portion and a curved corner portion in a complicated mixture and having an inclined standing wall portion in the depth direction. A method is to find a press-molding method that reduces wrinkles that occur in the inclined standing wall portion of the curved corner portion of the press-molded product, and to obtain such a wrinkle-free press-molded product.

[0006]

As a result of various studies on the method of reducing body wrinkles in an inclined standing wall portion of a curved corner portion, the present inventors have found that the tension control at the straight side portion and the corner portion suppresses body wrinkling. Or, it is effective to reduce the tension.By controlling the tension, the material inflow resistance of the flange at the corner is made larger than the material inflow resistance of the flange at the straight side, so that the molded product at the straight side and the corner It was found that it is possible to suppress or reduce body wrinkles that occur in the inclined standing wall portions of the corners of the press-formed product by making a difference in the tension applied to the inclined standing wall portions.

Further, in FIGS. 1 and 2, the magnitude of the tension applied to the inclined standing wall portion depends on R ₁ of the die 1 at the inclined standing wall portion (straight side portion 61, curved corner portion 71) in the molded product after press molding. There is a close relationship with the size of the shock line length of the part and the material (the length of the sliding part, the straight side part Ls, the curved corner part Lc), and the greater the tension, the shorter the shock line length. On the contrary, there is a relationship that the shock line length increases as the tension decreases. If the ratio Lc / Ls of the shock line length Lc at the center of the corner portion and the shock line length Ls at the straight side portion is set to 0.9 or less, the body wrinkles 9 of the inclined standing wall portion 71 at the corner portion can be reduced. I got the knowledge. The present invention has been made based on the above findings.

That is, according to the invention of claim 1 for solving the above-mentioned problems, the press-molding of the Al alloy plate of the draw-formed product comprising the straight side portion and the curved corner portion and having the inclined standing wall portion in the depth direction. In the method, the ratio of the initial flange length fc corresponding to the center of the curved corner portion to the initial flange length fs corresponding to the straight side portion is set to 0.8 or more to set the shock at the center of the curved corner portion. Ratio Lc between the line length Lc and the shock line length Ls on the straight side
/ Ls is 0.9 or less to reduce wrinkles generated in the curved corner inclined standing wall portion of the press-formed product, which is a press-forming method for an Al alloy plate,

A second aspect of the present invention is a press forming method using an Al alloy plate for a draw-formed product having straight sides and curved corners and having an inclined standing wall in the depth direction, which corresponds to the curved corners. By setting the ratio Pc / Ps of the initial surface pressure Pc of the flange to the initial surface pressure Ps of the flange corresponding to the straight side portion to 1.3 or more, the shock line length Lc at the center of the curved corner portion and the straight side portion A press forming method for an Al alloy plate, characterized in that a wrinkle generated in a curved corner inclined standing wall portion of a press formed product is reduced by setting a ratio Lc / Ls of a shock line length Ls to 0.9 or less,

The invention of claim 3 is a press-formed product made of an Al alloy plate having straight sides and curved corner portions and having an inclined standing wall portion in the depth direction, wherein a shock is formed at the center of the curved corner portion. A press-formed product of an Al alloy plate, characterized in that the ratio Lc / Ls of the line length Lc and the shock line length Ls at the straight side is 0.9 or less.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The invention of claim 1 for reducing body wrinkles of the inclined standing wall portion of the curved corner portion in a molded product of an Al alloy plate having a straight side portion and a curved corner portion and having an inclined standing wall portion in the depth direction, The ratio fc / fs of the initial flange length fc of the blank corresponding to the center of the curved corner portion and the initial flange length fs of the blank corresponding to the straight side portion is set to 0.
By setting the ratio to 8 or more, the ratio Lc / Ls of the shock line length Lc at the center of the curved corner portion of the molded product and the shock line length Ls at the straight side portion is set to 0.9 or less, and press molding is performed.

Generally, when a molded product having a straight side portion and a curved corner portion is press-molded, the flange corresponding to the curved corner portion of the blank is deformed by shrinking flange. Here, fc / fs is set to 0.8 or more, in the blank used for press forming, if the initial flange length fc corresponding to the curved corner portion becomes long, the deformation resistance of the contracting flange deformation becomes large, This is because when fc / fs is 0.8 or more, Lc / Ls becomes 0.9 or less and body wrinkles can be reduced. When fc / fs is less than 0.8, Lc / Ls exceeds 0.9, so that the generation of body wrinkles becomes remarkable.

Next, a straight side portion and a curved corner portion,
Also, in the molded product of the Al alloy plate having the inclined standing wall portion in the depth direction, the invention of claim 2 for reducing the body wrinkles of the inclined standing wall portion of the curved corner portion is the initial surface of the flange corresponding to the curved corner portion. By setting the ratio Pc / Ps of the pressure Pc and the initial surface pressure Ps of the flange corresponding to the straight side portion to 1.3 or more, the shock line length Lc at the center of the curved corner portion and the shock line length L at the straight side portion
In this method, the ratio Lc / Ls of s is set to 0.9 or less and press molding is performed. Here, Pc / Ps is set to 1.3 or more because Lc / Ls can be set to 0.9 or less, and body wrinkles can be reduced. Note that Pc
When / Ps is less than 1.3, Lc / Ls exceeds 0.9, so that the generation of body wrinkles becomes significant.

The specific method for setting the Pc / Ps to 1.3 or more is as follows. (1) In a die used for press molding, the clearance between the die for pressing the blank and the wrinkle holding plate is set so that the curved corner portion is smaller than the straight side portion, that is, P
Design so that c is large. (2) A piece of paper or an extremely thin plate is sandwiched between the flanges corresponding to the curved corners for molding. Alternatively, the beads are arranged on the flanges corresponding to the curved corners for molding. (3) Use the differential lubrication method. That is, the flanges corresponding to the straight sides are provided with lubricity by applying a lubricant,
On the contrary, the flange corresponding to the curved corner is non-lubricated,
Alternatively, the inflow resistance is increased by lowering the lubricity of the straight side portion and lowering the slidability of the flange at the curved corner portion. (4) When the clamping pressure of the flange can be divided and individually controlled, the clamping pressure (wrinkle pressing force) of the curved corner portion is set to be larger than that of the straight side portion. In this way, Pc is made larger than Ps, and Pc / Ps
Can be 1.3 or more.

Next, a third aspect of the present invention is a press-formed product made of an Al alloy plate having a straight side portion and a curved corner portion, and having an inclined standing wall portion in the depth direction, in the center of the curved corner portion. It is a press-formed product of an Al alloy plate in which the ratio Lc / Ls of the shock line length Lc and the shock line length Ls at the immediate side is 0.9 or less. This is a press-formed product of an Al alloy plate obtained by the invention of the press-forming method according to claims 1 and 2, and is a ratio Lc of the shock line length Lc at the center of the curved corner portion and the shock line length Ls at the straight side portion. In the press-formed product in which / Ls is 0.9 or less, the curved corner inclined standing wall portion has no wrinkles or few wrinkles.

The press molding method according to the present invention is
Although it has a remarkable effect when applied to an Al alloy plate having a small r value and easily wrinkling, it can also be applied to a steel plate or the like. Further, in press molding, in order to reduce the coefficient of friction, when the entire plate is subjected to surface treatment, for example, application of a solid lubricant or resin coating, it is more effective in reducing body wrinkles. This is because the material at the bottom of the punch flows out to the vertical wall of the molded product due to the reduction of the friction coefficient of the material, which shortens the shock line length and reduces body wrinkles. Further, with respect to the material subjected to such a treatment, a greater wrinkle holding force can be applied as compared with the material not subjected to the treatment, so that there is also an effect of suppressing wrinkles generated on the flange, that is, flange wrinkles.

[0017]

The preferred embodiments of the present invention will be described below.
Description will be made in comparison with the comparison method. (Example 1) A molded product 50 as shown in FIGS. 5, 6 and 7 was produced by a punch die having the shapes and dimensions shown in FIGS. 8 and 9. The approximate size of the molded product 50 is 600 mm length × 800 mm width × 70 mm depth (H). 5 to 7, A, B, C and D are positions of curved corners, a, b, c and d are positions of straight sides, and 70 is
Is a curved corner portion, 701 is the inclined standing wall portion, 60 is a straight side portion, 601 is the inclined standing wall portion, R ₂ is the radius (100 mm) at the curved corner portion A, and Lc is the center of the inclined standing wall portion of the curved corner portion. Shock line length, L
s is the shock line length on the sloped wall part on the straight side, 8
Reference numeral 01 is a flange portion of the molded product.

The blank for obtaining this molded product 50 is
5182-O material (A with a plate thickness of 1 mm, which is a 5000 series alloy
O of 1-4.5 wt% Mg-0.24 wt% Mn alloy
Material), as shown in FIG. 4, length 780 mm x width 960 m
corner ^A, in ^m, B,, C,, using the shape of the plate 30 obtained by cutting ^D, and. In FIG. 4, A ^, ... ^, D are the positions of the corners of the blank material corresponding to the corners A ^, D ^of the molded product, and a ^, ... D are the blanks corresponding to the positions a ^, d of the straight sides of the molded product. The position of the straight side portion of the material, 80 is the flange portion of the blank, fc is the initial flange length of the blank corresponding to the center of the curved corner portion, and fs is the initial flange length of the blank corresponding to the straight side portion.

In this molding, the blank shape and the position of the blank set in the mold are adjusted so that the remaining length of the flange is 40 mm when the molding depth is 70 mm, and the lubrication facilitates the inflow of the flange. To this end, a high-viscosity lubricating oil for press molding was applied to the flange portion. This condition is set as the reference condition, at the corner indicated ^A, and in FIG. 4, variously changing the length of the initial flange length fc of the blank as shown in Table 1 to 163Mm～43mm (Chokuhen section ^a,, The fs of d 1 ^and d 2 were both constant at 86 mm), and press molding was performed. The Lc of the A corner portion, the Ls of the straight side portions a and d, and the body wrinkle of the curved inclined standing wall portion of the A corner portion of this molded product shown in FIG. 5 were investigated, and the results are shown in Table 1. The condition of the crease pressing force at the initial flange length fc of each blank of A ^{and the} corner portion was increased to the limit at which breakage did not occur. The body wrinkles occurring on the standing wall of the molded product were evaluated by measuring the difference in the unevenness of the body wrinkles and evaluating the maximum value.

[0020]

[Table 1]

As is clear from Table 1, when the initial flange length fc of the blank is long and fc / fs is 0.8 or more, Lc / Ls is 0.9 or less and the body wrinkle height is low. You can see that it has become.

(Example 2) Test No. 1 in Table 1 Using the blank of No. 3, one sheet of 10 mm × 10 mm paper (thickness 20 μm) was sandwiched between the flange portions of the corner portions indicated by A in FIG. 4 ^, and press molding was performed. A in this ^case, the initial surface pressure of the flange of the corner portion Pc, Chokuhen portion ^{a,, d,} the initial surface pressure Ps of the flange was measured and noted in Table 2. The Lc of the A corner portion, the Ls of the straight side portions a and d, and the body wrinkle of the curved inclined standing wall portion of the A corner portion of this molded product shown in FIG. 5 were investigated, and the results are shown in Table 1. Incidentally, blank holding force was increased to the limit that does not cause breakage at the corner of ^A, as in Example 1. Regarding the measurement of the initial surface pressure, pressure-sensitive paper was used to convert the surface pressure from its color tone. Other conditions are the same as in the first embodiment. The evaluation of body wrinkles occurring in the A-corner standing wall portion of the press-formed product was measured in the same manner as in Example 1.

[0023]

[Table 2]

As is apparent from Table 2, when the paper piece is sandwiched between the corner flanges and the initial surface pressure P _C of the flanges at the corners is increased, Pc / Ps is 1.3 or more,
It can be seen that Lc / Ls is 0.9 or less and body wrinkles are reduced.

[0025]

As described above, according to the press forming method and the molded product of the Al alloy plate of the present invention, the length or surface pressure of the flange corresponding to the straight side portion and the curved corner portion of the molded product is changed. As a result, a difference is caused in the inflow resistance of the flange, and a difference is caused in the tension generated between the straight standing portion and the inclined standing wall portion of the curved corner portion. As a result, it is possible to reduce the body wrinkles that occur in the inclined standing wall portion of the curved corner portion of the press-formed product and improve the appearance of the molded product, which is a significant industrial effect.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a press molding method for molding an inclined standing wall portion.

FIG. 2 is a partial perspective view showing an inclined standing wall portion of a curved corner portion and an inclined standing wall portion of a straight side portion.

3 is a cross-sectional view taken along the I plane of FIG.

FIG. 4 is a view showing a shape of a test blank.

FIG. 5 is a plan view of a test molded article.

6 is a sectional view taken along line II-II of FIG.

7 is a sectional view taken along the line III-III at the corner A in FIG.

FIG. 8 is a plan view of a test molding punch.

9 is a sectional view taken along line IV-IV in FIG.

[Explanation of symbols]

1 Die R ₁ Chamfered part of die 2, 20 Punch 3, 30 Blank material of Al alloy plate 4 Wrinkle holder A to D Position of corner of molded product a to d Position of straight side of molded product A ^, D ^, position a punch or blank corresponding to the corner portion A~D of the molded ^article, to ^d, the position 5,50 moldings 6,60 molding of the blank corresponding to the position a~d straight sides of the shaped article Straight part of product 61,601 Sloping wall part of straight part 7,70 Curved corner part of molded product 71,701 Sloped wall part of curved corner part R ₂ Radius of A corner part of punch or molded product 8,80 Blank Flange part 81,801 Flange part of molded product 9 Wrinkle H Height of molded product Lc Shock line length at the center of inclined standing wall of curved corner part Ls Shock line length at inclined standing wall part of straight side fc Curved corner Flange initial surface pressure corresponding to the initial surface pressure Ps straight sides of the flange corresponding to the initial flange length Pc curved corner portion of the blank corresponding to the initial flange length fs straight sides of the blank corresponding to the center of the

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichiro Toji 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Within Furukawa Electric Co., Ltd. (72) Inventor Yoshihiro Matsumoto 1 Kawasaki-cho, Chuo-ku, Chiba-shi Inside the Steel Research Laboratory (72) Inventor Takaaki Hira 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Inside the Kawasaki Steel Research Laboratory (72) Inventor Akito Sato 1 Toyota-cho, Aichi Prefecture Toyota Automobile Incorporated (72) Inventor Shinichiro Nakamura 1 Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd.

Claims (3)

[Claims] 1. A press forming method using an Al alloy plate of a draw-formed product comprising straight sides and curved corners and having inclined standing walls in the depth direction, wherein a blank corresponding to the center of the curved corners is formed. By setting the ratio fc / fs of the initial flange length fc and the blank initial flange length fs corresponding to the straight side portion to 0.8 or more, the shock line length Lc at the center of the curved corner portion and the shock line length at the straight side portion. A press-forming method for an Al alloy plate, characterized in that the ratio Lc / Ls of Ls is set to 0.9 or less to reduce wrinkles occurring in the curved corner inclined standing wall portion of the press-formed product. 2. A press forming method using an Al alloy plate of a draw-formed product comprising a straight side portion and a curved corner portion and having an inclined standing wall portion in the depth direction, the initial surface of a flange corresponding to the curved corner portion. By setting the ratio Pc / Ps of the pressure Pc and the initial surface pressure Ps of the flange corresponding to the straight side portion to 1.3 or more, the shock line length Lc at the center of the curved corner portion and the shock line length Ls at the straight side portion are A method of press-forming an Al alloy plate, characterized in that the ratio Lc / Ls is set to 0.9 or less to reduce wrinkles occurring in the curved corner inclined standing wall portion of the press-formed product. 3. A press-formed product made of an Al alloy plate having a straight side portion and a curved corner portion and having an inclined standing wall portion in the depth direction, wherein the shock line length Lc and the straight side portion at the center of the curved corner portion. Shock line length Ls
A ratio of Lc / Ls is 0.9 or less
l Press-formed product of alloy plate.