JP2800952B2 - Hemming method for panel with line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for hemming the entire circumference of a thin aluminum plate such as an engine hood of a vehicle having a character line.

[0002]

2. Description of the Related Art Conventionally, in a part in which an outer panel and an inner panel are combined, such as a vehicle door, an engine hood, and a trunk lid, an end of the outer panel is
In order to make the edge of the flat plate strong and smooth, etc., a hemming process is performed such that the flange portion of the inner panel is wrapped and folded 180 degrees in close contact. For example, Japanese Patent Application Laid-Open No. 57-7332 is known as a processing die apparatus for such an edge bending, and this apparatus performs a pre-bend (pre-hem) after pre-bending a peripheral edge of a panel over a whole circumference with a pre-hem punch. The circumference is simultaneously bent (hemming). On the other hand, a relatively shallow raised portion may be formed at the center of the panel on the outer plate of the panel such as an engine hood for the purpose of enhancing the design. That is, in such a case, a raised step portion called a so-called character line is formed at the boundary between the raised portion and the flat portion, and making this character line is widely adopted in design.

[0003]

However, in the case of an aluminum panel having such a character line, if the entire circumference is simultaneously processed by the above-mentioned hemming processing apparatus, wrinkles may occur at the base of the character line. , The character line was deformed. This is especially true for materials with low tensile stiffness, such as aluminum, if the hemming method is adopted after preheming the entire circumference at the same time, and the stress applied from all sides is concentrated at the center of the panel at the same time, as if a character line was formed. This is probably because stress concentrates particularly on the character line part in the aluminum panel. Therefore, it is conceivable to increase the number of character lines to spread the stress,
Due to design constraints, it was not possible to increase it unnecessarily.

[0004]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides a hemming method for hemming the entire circumference of an aluminum panel having a line-shaped raised step portion such as a character line formed on the panel. The pre-hem punch preliminarily bends the flange portions at both left and right end portions along the line direction of the rising step portion, and retreats the pre-hem punch. After that, the entire circumference was simultaneously bent.

[0005]

[Function] First, both ends of the character line and the like along the line direction are preliminarily bent, and then the prehem punches at the both side ends are opened to preliminarily bend the front and rear ends of the line direction. In addition, concentration of stress at the center of the panel can be avoided. In other words, in the hemming process in which the entire periphery of the edge is folded simultaneously, the maximum stress is applied to the center of the panel at a folding angle from 90 degrees to a predetermined angle, that is, at the stage corresponding to the preliminary bending by the prehem punch, and thereafter the final bending is performed. It is considered that the stress applied to the center of the panel slightly decreases from the maximum stress when the folding angle approaches 180 degrees, but in the preliminary bending stage where the maximum stress is applied as in the present invention, the character line By pre-bending only both side ends in the direction along the line, and then opening the pre-bent side ends, pre-bending both ends in the front-rear direction of the line can distribute the stress. Then, when the preliminary bending of the edge portion is completed through this order, the entire periphery is fully bent at the same time. In other words, it is possible to prevent a wrinkle in the character line portion or a deformation of the character line by such a process.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for hemming a lined panel according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a plan view of an engine hood for a vehicle, and FIG. 2 is a positioning state diagram when hemming the engine hood.
3 and 4 are explanatory views showing a state of preliminary bending by a prehem punch, and FIG. 5 is a sectional view taken along the line BB of FIG. 1 for explaining the hemming method of the present invention. The left side from the center of the figure is an operation diagram of the prehem punch at the side end along the line direction of the character line, and the right side from the center is the operation diagram of the prehem punch at the side end in the front-rear direction of the line.

As shown in FIGS. 1 and 2, an engine hood 1 for a vehicle is formed by laminating an outer panel 2 and an inner panel 3 made of, for example, a thin aluminum plate having a thickness of about 1.0 to 1.5 mm. A shallow bulge 4 is formed at the center of the vehicle along the vehicle front-rear direction. The raised portion 4 of the outer panel 2 is combined with the inner panel 3 with the protruding portion projecting outward, and two right and left characters as a raised step formed at the boundary between the raised portion and the flat portion. Line 5
Will enhance the design.

The molding of the engine hood 1 is performed on a hemmed die 6 as shown in FIG.
1 is formed with a concave portion that fits into the raised portion 4 of the outer panel 2. The outer panel 2 in the state shown in FIG. 1 is positioned in an inverted posture, and the inner panel 3 is mounted thereon and positioned by the upper die 7. You.

Flanges 2a and 2b are provided on the peripheral edge of the outer panel 2, that is, flanges 2a at both left and right ends along the line direction of the character line 5.
, 2a and flange portions 2 on both sides in front and behind in the line direction
b and 2b, both of which are already bent at a right angle of about 90 degrees in the direction opposite to the direction in which the raised portion 4 projects. Then, the hemming method of the present invention uses the flange portions 2 a,
This is a processing method for further folding back 2b to the inner panel 3 side to wrap the edge of the inner panel 3 and tightly bend it.

That is, as in the prior art, when the flange portions 2a and 2b of the outer panel 2 are to be preliminarily bent and fully bent all over the circumference at the same time, wrinkles are formed near the base of the character line 5 shown in FIG. However, such a problem as to occur or the character line 5 to be broken and deformed is caused. Such a problem is prevented.

The configuration of the prehem punch and the hem punch will now be described with reference to FIGS. The pre-hem punch 9 is provided on the periphery of the hemmed die 6. That is, the cam driver 13 is attached to the attachment portion 10 of the hemmed die 6 so as to be swingable about a swing shaft 11, is urged counterclockwise in the drawing by a spring 12, and moves up and down together with the upper die base. A cam mechanism is formed between them.

That is, the prehem punch 9 is provided with a roller 14 capable of contacting the first cam 15 and the second cam 16 of the cam driver 13, and when the cam driver 13 descends to a predetermined position, the prehem punch 9 is moved to the first position. Cam 1
5, when the cam driver 13 further swings clockwise about the swing shaft 11 as shown in FIG.
The cam 16 swings counterclockwise. That is, when swinging clockwise, the flange portion 2a of the outer panel 2 is preliminarily bent inward, and swings counterclockwise to open the flange portion 2a. After that, the hem punch 17 that descends at a delayed position together with the cam driver 13 performs the main bending by pressing from above.

The configuration of the prehem punch 9 described above is the same on the other flange 2b side,
The height positions of the cam drivers 13a and 2b are different as shown in FIG. That is, in the cam driver 13 descending with the upper die base, the side of the flange 2a in the direction parallel to the character line 5 is low, the side of the flange 2b before and after the character line 5 is high, and the heights of the hem punches 17, 17 are the same.

When the upper die base is lowered from the positioned outer panel 2 and inner panel 3 in the processing apparatus having such a configuration, first, the flange portion 2 a in the direction parallel to the character line 5 is moved approximately 9 by the prehem punch 9.
It is pre-bent from 0 degrees by an angle of plus alpha. Next, the prehem punch 9 is separated from the flange portion 2a to open the same portion 2a, and then the flange portion 2b is preliminarily bent in the front-back direction of the character line 5. At this time, since the flange portion 2a for which the preliminary bending has already been completed is not restrained, stress concentrates on the character line portion 5 and wrinkles occur.
There is no problem such as deformation. Then, after the prehem punch 9 opens the same portion 2b, the hem punch 17 bends the entire flange portions 2a and 2b all at once. still,
The present invention is applicable to a configuration in which the above order is reversed, that is, when the preliminary bending of the flange portion 2b in the front-back direction of the character line 5 is performed first, and then the preliminary bending of the flange portion 2a in the direction parallel to the character line 5 is performed. It has proven to be less effective.

[0015]

As described above, according to the full hemming method of the present invention, the prehem punch is retracted by preliminarily bending the flanges at both ends along the line direction of the bulging portion, and then is moved back and forth in the line direction. Preliminary bending of the flanges at both ends of the panel is performed, and then the main bending is performed.Therefore, in the preliminary bending process where stress concentration tends to occur on the panel surface, wrinkles etc. The trouble that occurs can be prevented.

[Brief description of the drawings]

FIG. 1 is a plan view of an engine hood for a vehicle.

FIG. 2 is a positioning state diagram when hemming the engine hood, and is a cross-sectional view taken along line AA of FIG. 1;

FIG. 3 is a longitudinal sectional view of a prehem punch.

FIG. 4 is a longitudinal sectional view showing a pre-bending state by a prehem punch.

5 is a cross-sectional view taken along the line BB of FIG. 1 for explaining the process of the present invention. The left side of the figure is the side end along the line direction of the character line, and the right side of the figure is the same line. Side end in the front-rear direction

[Explanation of symbols]

(1) Engine hood (2) Outer panel (2a) (2b) Flange (3) Inner panel (5) Character line (9) Pre-hem punch (13) Cam driver (17) Hem punch

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takeshi Kikuchi 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) B21D 19 / 08

Claims (1)

(57) [Claims] 1. A method for hemming an entire circumference of a panel with a line, wherein the entire circumference of an aluminum panel having a line-shaped raised step formed on a panel surface is hemmed. Pre-bending the pre-hem punch with the pre-hem punch, and pre-bending the pre-hem punch at the front and rear ends of the raised step portion in the line direction. All the circumference of a lined panel.