JP2000051958A - Hemming work method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of defective forming such as roll over and turn over in the vicinity of a bend base part of a hemming flange part at a hemming coupling part. SOLUTION: In the case of performing works in order of flange bending, pre-hemming and hemming, a V-shaped groove-like notch part 5 is simultaneously formed in advance on the inner corner part of a bend base part of a hemming flange part in the case of the flange bending work. The notch part 5 is of a V-shaped groove, and its opening angle is preferably set to be in a range of 45-60 deg.. At the time of the pre-hemming work, the bending is started from the notch part 5 to prevent the generation of the roll over or the turn over.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hemming method for hemming an outer panel and an inner panel when assembling an opening / closing body such as a door of a motor vehicle. The present invention relates to a hemming processing method for preventing the occurrence of molding defects referred to as "whore", "shaking", etc.

[0002]

2. Description of the Related Art As shown in FIG. 6, in a hemming method for hemming a joint between an outer panel 1 and an inner panel 2, as shown in FIG. The occurrence is inevitable, and various countermeasures have conventionally been taken.

Here, the "who" means that the bent base of the hemming flange 3 does not have a smooth cylindrical surface whose diameter is equal to the thickness T _{1 of the} portion where the three hemming flanges are stacked.
Is a phenomenon in which the surface side of the lens is sagged by the dimension m.
“Shaking” is a phenomenon in which a part of the outer panel 1 is depressed by the dimension n.

The mechanism by which these phenomena such as "who" or "shaking" occur can be explained as follows.

As shown in FIG. 6A, a hemming flange 3 is bent and formed on the outer panel 1 before the outer panel 1 and the inner panel 2 are overlapped.
At that time, a portion Q having high hardness is generated at the bent base portion of the hemming flange portion 3 by work hardening.

Next, as shown in FIG. 1B, when a bending force F is applied to the hemming flange 3 by pre-hemming, a portion S of the general portion softer than the high hardness portion Q yields, With the general portion S as a fulcrum, a turning force f1 in the counterclockwise direction is generated, and the entire bent base portion jumps up in the same direction, thereby generating a "whore" m.

On the other hand, in the hemming process following the pre-hemming process, as shown in FIG. 1C, the weighting fulcrum F gradually moves rightward as the machining progresses, and moves to the right side of the previous bending fulcrum. Then, a clockwise rotational force f2 is generated around the bending fulcrum S as the rotation center, and the bending base is lifted up by the rotational force f2, so that “shrinkage” n is generated.

[0008] Then, since the above-mentioned "Dare" and "Shake" are plastically deformed and become permanent, they remain as they are even if the hemming force is released, as shown in FIG. .

The present inventors have studied in more detail the behavior in the high hardness portion Q generated when the hemming flange portion 3 is subjected to flange bending.

That is, as shown in FIGS. 7A and 7B, the hardness at the corner of the bent base after forming the hemming flange 3 is determined for four points a, b, c and d. As a result of the measurement, it was found that work hardening progressed as the portions a and c underwent elongation deformation and shrinkage deformation.
In other words, it has been found that by setting the fragile portion according to the hardness at each of the points a, b, and c, it is possible to suppress the above-described molding defects such as “slump” and “shrinkage”.

The present invention has been made in view of the above background, and a hemming in which the above-mentioned "slump" or "shrinkage" is suppressed by applying a slight pre-processing to the bent base of the hemming flange. It is intended to provide a processing method.

[0012]

According to a first aspect of the present invention, there is provided a flange bending step of forming a hemming flange by bending an end of a panel to be processed substantially at a right angle, and forming the hemming flange at a predetermined inclination angle. A pre-heming step of bending the panel toward the workpiece panel until the posture is reached, and a hemming step of further folding the hemming flange portion after the pre-hemming processing so as to be in contact with the panel to be processed. It is characterized in that a notch is formed at the inner corner of the bent base of the part.

According to a second aspect of the present invention, the depth of the notch in the first aspect of the invention is set to a range of 1/2 to 2/3 of the thickness of the panel to be processed as the base material. It is characterized by having.

Here, in the second aspect of the present invention, the depth of the notch is set in a range of 1/2 to 2/3 of the thickness of the panel to be processed as the base material. , Less than 1/2, the effect provided by the notch portion does not appear remarkably, and if more than 2/3, cracks occur in the panel to be processed due to the notch effect due to the formation of the notch portion. Because there is no.

According to a third aspect of the present invention, in the first or second aspect, the notch has a V-groove shape, and its opening angle is set in a range of 45 to 60 °. It is characterized by.

According to the third aspect of the present invention, the notch portion has a V-groove shape and its opening angle is 45 to 60 °.
If the angle is less than 45 °, the opposing two surfaces of the V-groove come into contact during the hemming process. If the opening angle of the V-groove exceeds 60 °, the effect of providing the notch itself cannot be expected.

According to a fourth aspect of the present invention, the notch portion according to the first aspect of the present invention is formed simultaneously with the flange bending.

According to a fifth aspect of the present invention, in the flange bending process according to the fourth aspect of the present invention, a panel to be processed is pressed and restrained by a punch and a pad, and then a flange die is formed in the same direction as the pressing direction. To form a hemming flange by relatively moving the notch, and the notch is formed by stamping with a coining bead protruding from the edge of the punch when the flange is bent. It is characterized by.

Therefore, according to the first to third aspects of the present invention, when the hemming flange portion is subjected to the pre-hemming process, the hemming flange portion is bent from the notch portion which is a fragile portion, so that "nobody" is generated. Further, as described above, the occurrence of "shaking" in the hemming step is also suppressed by suppressing the "droop" in the pre-heming step.

According to the fourth and fifth aspects of the present invention, the notch portion is simultaneously formed in the flange bending step for forming the hemming flange portion.

[0021]

According to the first aspect of the present invention, the notch is formed in advance in the inner corner of the bent base of the hemming flange, so that the notch becomes substantially weak. However, when the hemming flange is pre-hemmed, the hemming flange is bent from the notch. This has the effect of significantly improving the hemming quality.

Further, the depth of the notch portion is set in a range of 1/2 to 2/3 of the thickness of the base material as in the invention of the second aspect, or the invention of the third aspect is provided. By forming the notch portion in a V-groove shape and setting the opening angle in the range of 45 to 60 °, molding defects such as the above-mentioned “slump” and “shrinkage” can be more effectively prevented. effective.

According to the fourth aspect of the invention, since the notch is formed simultaneously with the flange bending of the hemming flange, there is no need to provide a separate step for processing the notch. In addition to reducing man-hours for hemming, as in the invention according to claim 5,
By forming the notch in the coining bead portion formed in the punch portion for flange bending by printing, the modification of the equipment for processing the notch portion can be minimized.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 5 show preferred embodiments of the present invention. In assembling an opening / closing body such as a door or a hood of an automobile, an example in which an outer panel and an inner panel are hemmed together. Is shown.

As shown in FIG. 1A, the outer panel 1 which has been formed into a predetermined three-dimensional shape is subjected to flange bending to form a hemming flange 3 at a substantially right angle. (B) after positioning the inner panel 2 similarly shaped into a predetermined three-dimensional shape on the outer panel 1 on which
As shown in (1), a pre-hemming process is performed in which the hemming flange 3 is bent to about 45 ° by a pre-heming die 4.

At this time, prior to the pre-hemming process, a notch portion 5 in the form of a V-groove is formed in the corner portion of the bent base portion of the hemming flange portion 3 in advance.

Since the portion where the notch portion 5 is formed becomes a fragile portion, as shown in FIG. 1B, during pre-hemming processing, the notch portion 5 is bent first to form a conventional shape. The occurrence of such “who” is suppressed.

The notch 5 is formed as shown in FIG.
The punch 6, the pad 7, and the sectional die 8 for flange bending work together to bend and form the hemming flange 3 on the outer panel 1 at the same time.

That is, the coining bead portion 9 is integrally formed at the corner edge of the punch 6 so as to protrude therefrom. The outer panel 1 is pressed and held between the punch 6 and the pad 7 and then subjected to flange down processing by the sectional die 8. At the time of application, the V-groove-shaped notch 5 is formed by the pressure of the sectional die 8 and the coining bead 9 with the working force of the sectional die 8.

Here, as shown in FIG. 2 and FIG. 3, the maximum depth of the notch 5 is about 1/2 to 2/3 of the thickness t of the outer panel 1 as a base material, and the opening angle thereof θ is 4
It is about 5 to 60 °. The notch 5 has a thickness t
If less than の of the above, the above-mentioned “slump” suppressing effect is poor, and if more than ／, a crack is generated from the deepest part of the notch 5 when preheming or hemming is performed. It is not preferable. If the opening angle θ of the notch portion 5 is smaller than 45 °, two opposing surfaces of the V-groove-shaped notch portion 5 come into contact with each other during the pre-hemming process, so that the effect of suppressing “drip” can be expected. On the other hand, if it exceeds 60 °, the original effect of the notch 5 cannot be expected.

After the pre-hemming process is performed as described above, the hemming process is performed by the hemming die 10 as shown in FIG. 1C, and finally, as shown in FIG.
As shown in (1), the processing force by the hemming die 10 is unloaded.

At this time, as shown in FIGS. 1C and 1D, when the hemming process is started after the pre-heming process is completed,
Although the weighted fulcrum F in the hemming flange portion 3 gradually moves to the right, since the "whore" is suppressed by the effect of the notch portion 5, subsequent "shrinkage" is less likely to occur. Even in the unloading state shown in FIG. 1D, the occurrence of molding defects such as “slump” or “shrinkage” is minimized.

FIG. 4 is a diagram showing the correlation between the depth of the notch 5 and the occurrence of "droop" and "swelling". The case where the notch 5 is formed is better than the case where the notch 5 is not formed. Both “Darling” and “Shaking” are largely suppressed, and the effect of suppressing the “Darling” and “Shaking” is more remarkable when the depth of the notch portion 5 is set to ／ of the base material plate thickness t. Has appeared. In each case, the base material plate thickness t was 0.75 mm and the opening angle of the notch 5 was 45.
°, the length of the hemming flange 3 was 8 mm.

FIG. 5 is a diagram showing the correlation between the opening angle θ of the notch 5 and the occurrence of “droop” and “skew”. The notch 5 having an opening angle of 45 ° as compared with the case where the notch 5 is not formed. "Who" and "Shakure" when forming
Both of them are greatly suppressed, and the effect of suppressing the above-mentioned "Dare" and "Shaking" is more remarkable when the opening angle of the notch portion 5 is set to 60 °. In each case, the base material plate thickness t was 0.75 mm, the depth of the notch portion 5 was t / 2, and the length of the hemming flange portion 3 was 8 mm.

As described above, according to the present embodiment, the formation of the hemming is prevented by forming the notch portion 5 so as to prevent molding defects such as "slump" or "shrinkage" at the time of pre-hemming or hemming. There is an advantage that the processing quality can be improved, and the notch portion 5 is processed simultaneously with the flange bending process, so that the number of steps is not increased.

[Brief description of the drawings]

FIG. 1 is a process explanatory view showing an embodiment of a hemming method according to the present invention.

FIG. 2 is an explanatory view of a process when a notch portion is processed simultaneously with a flange bending process.

FIG. 3 is an enlarged view of a main part of an outer panel in which a notch portion is formed.

FIG. 4 is a characteristic diagram showing a relationship between the depth of a notch portion and molding defects such as “sharpness” and “sharpness”.

[Fig. 5] Opening angle of notch, “who” and “shakure”
FIG. 4 is a characteristic diagram showing a relationship with molding defects such as the following.

FIG. 6 is an explanatory process diagram showing an example of a conventional hemming method.

FIG. 7 is an explanatory view at the time of measuring work hardening at a conventional hemming flange portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Outer panel 2 ... Inner panel 3 ... Hemming flange part 5 ... Notch part

Claims (5)

[Claims] 1. A flange bending step of forming a hemming flange by bending an end of a panel to be processed substantially at a right angle, and a pre-hemming step of bending the hemming flange toward a panel to be processed until the hemming flange has a predetermined inclination angle posture. And a hemming step of further folding back the hemming flange portion after the pre-hemming process so as to be in contact with the panel to be processed. Prior to the pre-heming process, a notch portion is formed at an inner corner portion of the bent base portion of the hemming flange portion. A hemming method characterized by forming. 2. The hemming process according to claim 1, wherein a depth of the notch portion is set in a range of 1/2 to 2/3 of a plate thickness of a panel to be processed as a base material. Method. 3. The notch portion has a V-groove shape.
The hemming method according to claim 1, wherein the opening angle is set in a range of 45 to 60 °. 4. The notch portion is formed at the same time as a flange bending process.
The hemming method according to any one of Items 1 to 3, above. 5. The flange bending process forms a hemming flange portion by pressing and restraining a panel to be processed by a punch and a pad and then relatively moving a flange die in the same direction as the pressing direction. The hemming method according to claim 4, wherein the notch portion is formed by stamping with a coining bead portion projecting from an edge of the punch when the flange is bent.