JPS6146207B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for curling the entire circumference of a sheet metal molded product surrounded by a three-dimensional curve, such as a vehicle bumper of a motorcycle fender.

Products such as motorcycle fenders and vehicle bumpers are obtained by bending a metal plate into a U-shaped cross section and forming all or part of the side surface into a curved arc shape. In such molded products, if the cut surface of the plate material at the end part remains as it is, it may be dangerous in the event of an accident or maintenance.
Vibrations during driving may cause cracks in the device. For this purpose, curling is performed to wrap the end portion.

Conventionally, when making this type of fender etc. by drawing,
Cut a board larger than the dimensions of the unfolded shape of the fender, etc., draw it into the shape of the fender, etc. so that the remaining pieces remain around the entire circumference, trim the remaining pieces, and then cut the outer circumference of the fender, etc. from side to side, front and back. It is bent multiple times, then curled multiple times on the left and right sides, front and back, and finally restriked.
A product is obtained by polishing with a buff or the like.

The methods of applying curling to the molded product obtained by the conventional drawing process described above include bending, bending,
Curling requires multiple processes, which requires a large number of man-hours, and requires additional molds and equipment.
The processing work is also complicated, troublesome, and time-consuming, and requires a large amount of manpower, resulting in poor mass productivity and high production costs.

The present inventors have developed the present invention in order to solve the above-mentioned problems in full-circumference curling of fenders and the like obtained by drawing.

The object of the present invention is to draw and form a fender material with a U-shaped cross section and an arc shape on the side, integrally form a remaining piece around this, cut it leaving a curling allowance, and at the same time prepare a fender material. After bending or cutting and pre-bending separately, the entire circumference is press-formed at the same time in a direction approximately perpendicular to the surface of the board using a die with a profile for the curled part, and the fender is formed by drawing. To reduce the number of processes for bending and curling around the edges when obtaining a To provide a method for curling the entire circumference of a fender for a motorcycle, etc., which makes it possible to obtain a fender, etc. that requires processing at low cost while improving mass productivity.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 to 7 show the first invention according to the present invention, and the embodiment shows an example of forming a fender for a motorcycle, in which a steel plate material is punched sufficiently larger than the developed shape of the fender, and a flat basic shape (not shown) is formed. Get the material.

The basic material was drawn and formed into an inverted U-shaped cross section and an arcuate side surface, as shown in FIGS. 1 and 2.
A drawing material W as shown in the figure is obtained, and the material W is bent approximately at right angles to the fender main body W ₁ having an inverted U-shaped cross section and an arcuate side surface, and is extended outward from the end portion of its entire periphery. The small width flange part W ₂ and the flange part
It is provided with an extra piece W ₃ that is bent downward from the end portion of the entire peripheral edge of W ₂ at a substantially right angle, and these pieces are integrally formed by drawing. The remaining piece W ₃ hanging around the entire periphery of the material W is formed to be sufficiently longer than the curling allowance.

Next, the remaining piece _W3 of the material W is cut in the vertical direction leaving a curling allowance. That is, as shown by the chain line in Fig. 5, when the remaining piece is rolled up to the bottom of the flange part _W2 to form a curled part _W1 of a predetermined diameter, the dimension a, which is the expanded dimension b of this part, remains in a hanging state. The curling allowance W ₄ is formed as shown in FIGS. 3 to 5. Then, as shown in Fig. 5, the upper female blade 1 and the lower male blade 3 cut from the outer side to the inner side of the remaining piece, that is, side cut, and the upper female blade 1 cuts the remaining piece from the outside to the inside. The step part 2 is formed in advance, and the machining allowance W ₄ is
In addition to removing the remaining pieces while leaving the
The lower end of W ₄ is bent inward to form an inwardly bent pre-bent portion W ₅ at the lower end of the machining allowance. The machining allowance and preliminary bending portion are formed around the entire periphery of the flange portion _W2 of the main body _W1 .

As described above, the curling allowance W ₄ is formed on the remaining piece W ₃ , and the intermediate material W ₆ as shown in FIGS. 3 to ₅ , which has a pre-bent portion W 5 formed at the lower end thereof, is curled. The curling process is as shown in Fig. 7. The main body _W1 of the material _W6 is held between upper and lower molds, etc., and the curling die 4 is applied from below the processing allowance _W4 , and the die 4 follows the curling profile. Ivy U
The die 4 may be an integral piece having the forming groove 5 on the upper surface of the entire circumference, or may be divided into front and rear, _left and right parts. In other words, the plate with the machining allowance W ₄ is advanced in the forward direction, the machining allowance W ₄ is rolled inward, and the sixth
A curled portion W7 as shown in FIG. ₇ is formed.
During forming, the processing allowance W ₄ has a pre-bent portion W ₅ whose lower end is bent inward, so that it is guided by the curved surface and bent without biting into the forming groove 5, and is easily rolled up. , ensure curl part W ₇
will be formed. In this way, a fender _W8 having a curled portion _W7 around the entire circumference is obtained.

The material W drawn and formed in this way is subjected to side cutting in one step and preliminary bending at the same time.
Curled parts at the end of the entire circumference with one-step curling molding
W ₇ can be formed, the cutting and curling processes require a minimum number of steps, and the equipment is also required to a minimum, making it possible to curl the entire circumference of the fender easily, inexpensively, and even for mass production.

Figures 8 to 16 show the second invention of the present invention, in which a flat basic material is obtained by punching out a steel plate material sufficiently larger than the developed shape of the fender, and the cross section of this material is an inverted U shape. 8 and 9.
A drawing material _W10 as shown in the figure is obtained.

The material W ₁₀ has a fender main body W ₁₁ with an inverted U-shaped cross section and an arc-shaped side surface, and a small flange portion W ₁₂ that is bent approximately at right angles to the end of the entire periphery and extends outward. , an extra piece W ₁₃ that hangs down at a substantially right angle from the end of the entire periphery of the flange portion W ₁₂ , and an extra piece W ₁₃ that is bent and extended outward from the lower end of the entire periphery at an approximately right angle thereto. and an extra flange portion _W14 , which are integrally formed by drawing. Material W ₁₀
The extra piece W ₁₃ including the extra flange part W ₁₄ is formed to be sufficiently larger than the curling allowance.

Next, the remaining flange portion W ₁₄ of the material W ₁₀ is cut leaving a length for curling. That is, the 12th
As shown by the chain line in the figure, when winding the extra piece to the bottom of the flange part W ₁₂ to form a curled part W ₁₈ of a predetermined diameter, the dimension a obtained by expanding the dimension b of this is the extra piece.
W ₁₃ , cut the extra flange portion W ₁₄ at a point with the total dimension from the lower end outward to the base of the extra flange portion W ₁₄ . As shown in Fig. 12, a cut is made at the base of the extra flange part W14 using the upper female blade 11 and the lower male blade ₁₂ , and the total dimension a of the base of the extra flange part and the extra piece is the dimension of the curled part _W18 . , and insert a step 1 at the end of the male blade 12 below the cut.
3, and form a downward pre-bent portion W ₁₆ at the outwardly bent tip of the obtained machining allowance W ₁₅ .

The part with the processing allowance W ₁₅ is bent downward by bending, and this is shown in Figs. 13 and 14 to form a processing allowance that allows curling from the vertical direction.
Form W ₁₇ . Processing allowance W ₁₇ is the main body W ₁₁ facing downward.
As a result of being bent in a substantially perpendicular direction, the previously described pre-bent portion _W16 faces inward, similar to the state shown in FIGS. 3 and 4 of the previously described first invention.

Finally, the curling allowance W ₁₇ is curled inward by the curling die 14 having the forming groove 15 similar to that described above, and the curling portion W ₁₈ is formed. Figure 15 shows the Fuender W ₁₉ .

According to the present invention, the bending process is added by one step compared to the above-mentioned method, but it will be understood that the number of cutting and curling steps is still significantly reduced compared to the conventional method.

As is clear from the above, according to the present invention, a curled portion can be formed around the entire circumference of a fender etc. in the minimum number of steps, and the number of forming steps is significantly reduced compared to the conventional method.
Workability and efficiency are greatly improved and curling molding, fenders, etc. can be easily and efficiently formed.This also requires minimal molding equipment, making fenders, etc. reasonably inexpensive, and improving mass productivity. It has many advantages, such as being able to be molded while tightening, and the precision of the curling molded part of the obtained product and the good external shape.

Although the above description has been made for a fender, it goes without saying that the present invention can be carried out when applying full-circumference curling to a bumper or other draw-formed product.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and Fig. 1 to Fig. 7 show the first invention, Fig. 1 is a perspective view of the drawn product, Fig. 2 is an enlarged longitudinal sectional end view of the same, and Fig. 3 The figure is a perspective view of the side cut state, Figure 4 is a view similar to Figure 2 in the same state, Figure 5 is an explanatory diagram of the side cut and preliminary bending, Figure 6 is a perspective view of the curled product, and Figure 7 8 to 16 show the second invention of the present invention, FIG. 8 is a perspective view of the drawn product, and FIG. 9 is a longitudinal sectional end view of the same, Figure 10 is a perspective view of the cut state;
Figure 1 is a view similar to Figure 9 in the same state, Figure 12 is an explanatory diagram of the same state, Figure 13 is a perspective view of the full circumference bend state, and Figure 14 is a view similar to Figure 9 in the same state. , 1st
FIG. 5 is a perspective view of the molded product, and FIG. 16 is a view similar to FIG. 9 in the same molded state. In the drawing, W and W ₁₀ are drawn products, W ₃ and W ₁₃ are extra pieces, W ₄ and W ₁₇ are machining allowances, W ₅ and W ₁₆ are pre-bending parts, and W ₇ and W ₁₈ are curled parts. .

Claims (1)

[Claims] 1. A metal plate material can be trimmed all around with a side cut, has a bulge in a curling shape, and is drawn with a surplus larger than the curling allowance below, so that the developed length of the curling part is The remaining piece is cut so as to leave a machining allowance with a dimension equal to , and a pre-curling bend occurs at the end of the machining allowance, and then the curling allowance is curled with a curling mold having a three-dimensional curved profile of the curling part of the molded product. A method for forming a motorcycle fender, etc. by curling the entire circumference thereof. 2. A metal plate material can be trimmed, with a curling-shaped bulge at the bottom, and a flange part left in the shape of a wrinkled surface around the periphery, by drawing to form a remaining piece, with dimensions equal to the unfolded length of the curling part. The flange portion of the remaining piece is cut so as to leave a machining allowance and to produce a pre-curling bend at the end of the machining allowance, and then pre-bend the remaining flange portion downward into a shape that can be curled from the vertical direction. 1. A method for full-circumference curling of motorcycle fenders, etc., characterized in that the curling area is then formed using a curling mold having a three-dimensional curved profile of the curling part of the molded product.