JP2569839B2 - Press die for corner hemming and method for processing hemming of corner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to hemming, and more particularly to a hemming press die for forming a corner and a method for hemming a corner.

[Related Art] Of two press products, a hemming process in which one of the press products is fixed by bending a flange of one of the press products and inserting the other press product into each other is often used, for example, when manufacturing an automobile body. I have. In the hemming process, generally, after the flange portion is preliminarily bent, the flange portion is bent to 180 °. As an example of an apparatus for performing such hemming processing, Japanese Patent Application Laid-Open No. 55-68133 and Japanese Utility Model Application Laid-Open No. 59-39019 are known.

FIGS. 7A to 7D show a conventional hemming process. In FIG. 7A, the outer panel 1 is placed on the lower mold 11, and the inner panel 2 is placed on the outer panel 1. On the outer peripheral portion of the outer panel 1, there is formed a flange portion 1a which rises substantially at a right angle. When the outer panel 1 and the inner panel 2 are placed on the lower mold 11, as shown in (d) of FIG.
Folded near. When the bending of the flange portion 1a by the preliminary curved blade 13 is completed, as shown in FIG. 7C, the preliminary curved blade 13 retreats, and the hem blade 14 descends toward the flange portion 1a. Then, the flange portion 1a is pressed by the hem blade 14, and the outer peripheral portion of the inner panel 2 is sandwiched by the outer panel 1 as shown in (d) of FIG.
The outer panel 1 and the inner panel 2 are integrated.

The hemming process is performed not only in the shape shown in FIG. 7D, but also in the outer panel 1 as shown in FIG.
Some of them have a corner 3 formed on the side. The hemming process for forming such a corner 3 cannot be performed in the same manner as in FIG. In other words, the base portion of the flange portion 1a bends simply by being pressed by the preliminary bending blade 13, so that this processing requires the core metal 15 as shown in FIG.

Thus, when the flange 1a is preliminarily bent, the core metal
By means of 15, the base of the flange portion 1a can maintain a predetermined angle. Then, the preliminarily bent flange portion is bent by the upper bending blade 16 so that the corner 3 shown in FIG. 8 can be formed.

[Problems to be Solved by the Invention] However, the pre-bent flange portion 1a is
When simply bent by pressing 16, there is a problem that the vertical wall (outer peripheral wall) of the corner edge 3 falls inward due to the effect of the bending, and a predetermined shape cannot be obtained.

FIG. 10 shows an example of a process of bending the pre-bent flange portion with an upper bending blade. In the drawing, (a) shows a state in which the bending of the flange portion 1a has been started by the upper curved blade 16, and in this state, the vertical wall 1b of the flange portion 1a of the outer panel 1 is the outer peripheral portion of the lower die 11. Close contact with 11a. When the upper curved blade 16 descends, as shown in FIG. 10 (b), the flange portion 1a is bent downward, so that the upper portion of the vertical wall 1b separates from the outer peripheral portion 11a of the lower die 11 and falls down inward. I will. Therefore, the shape of the corner 3 shown in FIG. 10 (c) is not formed as designed, and the desired function cannot be exhibited.

FIG. 11 explains the reason why the flange portion 1a falls down. As shown in FIG. 11, when the outer panel 1 and the upper curved blade 16 come into contact with each other, the vertical reaction force N and the friction due to the friction are generated. A horizontal force μ acts. The resultant force is represented by = + μ, and the moment acting on the point a in the figure is represented by a value obtained by multiplying the distance L between the points a and b by the vertical component Fb of the distance L. When the value of Fb × L increases, the vertical wall 1b of the flange portion 1a tends to fall inward with the lowering of the upper curved blade 16 as described above.

The present invention provides a pressing function of the vertical wall portion of the flange portion to the upper curved blade, thereby preventing the vertical wall portion of the pre-bent flange portion from falling inward during the corner forming by the upper curved blade. It is an object of the present invention to provide a press die for corner edge hemming and a method for processing corner edge hemming.

[Means for Solving the Problems] A press die for corner edge hemming and a method for processing a corner edge hemming according to the present invention that meet this object are as follows.

(1) A lower die set with the outer panel and the inner panel superimposed, an upper die that can be raised and lowered with respect to the lower die, and a pad that is located between the upper die and the lower die. A core bar supported so as to be able to hold the outer panel and the inner panel by the core bar, and press a flange portion of the outer panel from the outside to bend the flange portion along the core bar toward the inner panel. After the preliminary bending of the flange portion of the outer panel by the preliminary curved blade, an upper curved blade that presses the tip of the flange portion against the inner panel to form a square edge; An engaging means for engaging the tip of the flange portion at the time of forming the edge and pressing the vertical wall of the flange portion to a predetermined portion of the lower die.

(2) A core metal is pressed against the inside of the flange portion of the outer panel set on the lower mold by being overlapped with the inner panel,
The flange portion is preliminarily bent to the inner panel side along the metal core by pressing the flange portion from the outside with a preliminary curved blade, and after the core metal is retracted from the flange portion, it is lowered to the tip of the flange portion. While pressing the vertical wall of the flange part formed by the preliminary bending by engaging the engaging means formed on the upper curved blade to a predetermined portion of the lower mold,
A corner edge hemming method, wherein the edge of the flange portion is pressed against the inner panel by an upper curved blade to form a corner edge.

[Operation] In the press dies for corner edge hemming and the method for processing the corner edge hemming of the above (1) and (2), the flange portion of the outer panel preliminarily bent by the core bar and the pre-curved blade is: The upper curved blade presses the inner panel to form a square edge. In this case, since the upper curved blade is provided with an engagement means for engaging with the tip of the flange portion,
With the lowering of the upper curved blade, the vertical wall of the flange portion is pressed against a predetermined portion of the lower die in contact with the vertical wall. That is,
The flange portion engages with the engaging means, so that a load in the buckling direction acts on the flange portion when the upper curved blade descends, and the vertical wall of the flange portion is moved to a predetermined portion of the lower mold by the load in the buckling direction. Pressed toward.

Therefore, the shape of the vertical wall of the flange portion follows the shape of the predetermined portion of the lower die, and the corner is formed into a desired shape.

Example Hereinafter, a preferred example of a press die for corner hemming and a method for processing a corner hemming according to the present invention will be described with reference to the drawings.

1 to 6 show an embodiment of the present invention. In the figure, reference numeral 31 denotes a lower die, on which an outer panel 21 and an inner panel 22 are set. The inner panel 22 is mounted on the upper surface of the outer panel 21. A flange 21a bent at about 90 ° is formed on the outer peripheral portion of the outer panel 21.

Above the lower die 31, the upper die 32 is located, and the upper die 32
Are mounted on a ram of a press machine (not shown). The upper die 32 has a rod 33 extending downward. A plate-like pad 34 is provided between the upper 32nd and the lower mold 31. The pad 34 is fixed to the lower mold 31 via a support 35. Between the upper mold 32 and the pad 34, a plurality of compression springs
36 are interposed.

A core bar 37 is located between the pad 34 and the lower mold 31. The core bar 37 is swingably supported by the pad 34 via two arms 38. The two arms 38 are parallel, and the connecting portion of each arm 38 is a pin connection.
That is, in this embodiment, the parallelogram link mechanism is configured by the pad 34, the core bar 37, and the two arms 38. A lower end portion of one side of the core bar 37 is formed in a core bar portion 37a that presses the flange portion 21a of the outer panel 21 and the inner panel 22. A rotatable roller 39 is attached to the core bar 37 on the side opposite to the core bar 37a. The core bar 37 is a tension spring
It is connected to the pad 34 via 40, whereby the metal core 37 is drawn to the pad 34 side.

The rod 33 of the upper die 32 extends downward through the pad. In the groove of the rod 33, a cam 41 that can contact the roller 39 of the cored bar 37 is provided. The cam 41 is movable in a direction perpendicular to the direction in which the upper die 31 moves. The cam 41 is connected to an air cylinder (not shown), and the cam 41 comes into contact with the roller 39 only when the upper mold 32 is lowered. The air cylinder is connected to a valve (not shown), and the valve operates based on the up / down operation of the upper mold 32. When the roller 39 and the cam 41 come into contact with each other, the metal core 37 swings toward the flange portion 21a of the outer panel 21, and the metal core portion 37a moves to the flange portion 2 of the outer panel 21.
The inner wall of 1a and the inner panel 22 are pressed.

As in the present invention, in a press die for forming a corner edge, as in a general hemming process, a preliminary curved blade (pre-blade) is used.
51 and an upper curved blade (hem blade) 61 are used. The preliminary curved blade 51 and the upper curved blade 61 move with the movement of the upper die 32.

The spare curved blade 51 is attached to the holder 52,
52 is swingably supported by a block 55 fixed to the lower mold 31 via two arms 53 and 54. Two arms 5
3 and 54 are parallel, and the connecting portion of each arm 53 and 54 is a pin connection. That is, the holder 52, the block 55, and the two arms 53 and 54 form a parallelogram link mechanism. A guide roller 56 is attached to the arm 53, and the guide roller 56 can contact a block 57 provided on the upper die 32. The spare curved blade 51 presses the flange portion 21a of the outer panel 21 by the contact between the block 57 and the guide roller 56, as shown in FIG. A tension spring 58 whose one end is fixed to the block 55 is connected to one end of the one arm 53.

The upper curved blade 61 is attached to a holder 62, and the holder 62
Is swingably supported by the upper mold 32 via two arms 63. The two arms 63 are parallel and each arm
The 63 connection portions are pin connections. In other words, upper mold 32
The holder 62 and the two arms 63 constitute a parallelogram link mechanism. A guide roller 64 is attached to the other of the holder 62, and the guide roller 64 is a lower die.
The groove 65 of the block 65 fixed to 31 can enter. Thereby, the upper curved blade 61 presses the pre-bent flange portion 21a when the upper die 32 is lowered.

The lower end surface of the upper curved blade 61 has a flange 21
An engaging means 71 is provided which engages with the leading end of a and presses the vertical wall 21b of the flange portion 21a against a predetermined portion (the step surface 31a) of the lower mold 31. FIG. 2 shows a detailed cross section of the engaging means 71, and the engaging means 71 is constituted by a plurality of concave portions. In the present embodiment, the engaging means 71 includes a first concave portion 72 and a second concave portion 73.
It is composed of The first recess 72, the cross-sectional shape has a triangular, the apex angle theta ₁ has a 120 ° ± 10 °. Also, one of the elevation angle alpha ₁ is consistent with the angle alpha previous bending of the flange portion 21a. The side 72a of the first recess 72 is
It is a portion where the distal end surface of the flange portion 21a contacts.

The second recess 73 is provided adjacent to the first recess 72. Second recess 73 is likewise turned sectional shape as a triangle, the apex angle theta ₂ has a 120 ° ± 10 °. Also,
One elevation alpha ₂ is consistent with the first angle at the time of completion of the bending by the recess 72 beta of the flange portion 21a. The side 73a of the second concave portion 73 is a portion where the distal end surface of the flange portion 21a contacts.

The connecting portion 75 between the first concave portion 72 and the second concave portion 73 is set at the same height as the lower end surface of the upper curved blade 61. The upper curved blade 61 has an inclined surface 76 for forming the corner 23.

Next, the operation of the press machine for corner hemming and the method for processing the hemming of the corner will be described.

FIG. 4 shows the operation sequence of each part of the press die during hemming descent. First, the outer panel 21 and the inner panel 22 are set on the lower die 31. When the setting of the outer panel 21 and the inner panel 22 is completed, the ram (not shown) of the press machine is lowered, and the upper die 32 is lowered accordingly. The pad 34 comes into contact with a projection bar (not shown) extending from the lower mold 31 and stops at a fixed position. Further, when the upper die 32 moves down, the rod 33 provided with the cam 41 also moves down, and the cam 41 comes into contact with the roller 39 of the metal core 37. Therefore, the core metal 37 swings obliquely downward toward the flange portion 21a of the outer panel 21, as indicated by the arrow (a) in FIG.

Further, when the upper die 32 moves down, the roller 39 comes to be positioned at the top of the cam 41 as shown in FIG. In this state, the swing amount of the core bar 37 becomes maximum,
The flange part 21a of the outer panel 21 is formed by the core metal part 37a of 37.
The base portion of the inner wall surface and the outer peripheral portion of the inner panel 22 are pressed with a sufficient force. In this case, the block 57 of the upper die 32 shown in FIG. 5 abuts against the guide roller 56 attached to the arm 53, and the spare curved blade 51 is pressed against the outer wall surface of the flange portion 21a of the outer panel 21. Is done. Therefore,
In this state, as shown in FIG. 6, the flange portion 21a of the outer panel 21 is bent along the metal core portion 37a.

When the preliminary bending of the flange portion 21a is completed, the upper die 32 further descends, and the cam 41 passes through the roller 39 of the cored bar 37, and the cam 41
The contact between 41 and roller 39 is completed. Therefore, the core metal 37 is
The original position is returned by the tensile force of the tension spring 40, and the preliminary curved blade 51 is also returned. In this case, the core bar 37 is swung obliquely upward by the link mechanism, and is returned to the original position. Therefore, the core bar 37a of the core bar 37 is formed by the pre-bent flange 21a.
Without being interfered with, the flange 21a is prevented from being damaged by the interference with the cored bar 37.

When the mandrel 37 separates from the flange portion 21a, as shown in FIG. 1, the upper curved blade 61 descends with the lowering of the upper mold 32, and the upper end of the pre-bent flange portion 21a becomes the upper curved blade 61. Pressed by. The upper curved blade 61 has a first concave portion 72 and a second concave portion.
73 is formed, and in the state of (a) in the figure, the tip of the flange portion 21a engages with the first concave portion 72. First recess 72
When the tip of the flange portion 21a engages with the upper curved blade 61, a load acts on the flange portion 21a in a direction to buckle the flange portion 21a with the lowering of the upper curved blade 61, and the vertical wall 21b of the flange portion 21a is lowered. It is pressed against the step surface 31a of the mold 31. Therefore, even if the front end of the flange portion 21a is bent, the vertical wall 21b is formed on the lower mold step surface.
The problem that the vertical portion 21b is deformed due to the influence of bending while being in close contact with 31a is solved.

When the pressing of the flange portion 21a by the first concave portion 72 is completed, the tip of the flange portion 21a is shifted from the first concave portion 72 to the second concave portion 73, as shown in FIG. The transition of the distal end of the flange portion 21a is naturally performed as the upper curved blade 61 descends.

As shown in FIG. 1C, when the tip of the flange portion 21a is engaged with the second concave portion 73, the flange portion 21a is attached to the flange portion 21a as the upper curved blade 61 descends. A load acts in the buckling direction, and the vertical wall 21b of the flange portion 21a is pressed against the step surface 31a of the lower die 31. Further, as the upper curved blade 61 descends, the engagement between the tip of the flange portion 21a and the second concave portion 73 ends, as shown in FIG.
Are formed in a U-shape. And further, the flange portion 21a
Is pressed against the upper surface of the inner panel 22 by the lowering of the upper curved blade 61. As a result, as shown in FIG.
The flange portion 21a is pressed by the inclined surface 76 of the upper curved blade 61, and a corner 23 having a predetermined shape is formed on the outer peripheral portion of the outer plate 21.

As described above, when the upper curved blade 61 descends, the tip of the flange portion 21a is engaged with the first concave portion 72 and the second concave portion 73 in a stepwise manner, so that the shape of the vertical wall 21b is the shape of the lower mold. This follows the shape of the vertically formed step surface 31a, and the vertical wall 21b is formed into the designed shape.

FIG. 3 shows the flange portion 21a when the upper curved blade 61 is lowered.
An example of the force acting on the upper curved blade 61 and the direction of the force acting on the upper curved blade 61 are shown in FIG. It becomes larger than the frictional force μF received from the curved blade. for that reason,
The direction of the resultant force F 'is larger than the resultant force F received from the upper curved blade having a flat bottom surface, and its vector direction is the same as that of the flange 21a.
Approaching the lower end Z of. Therefore, the bending moment received by the flange portion 21a becomes small, and as a result, the flange portion 21a
The problem of the 21a being bent from the lower end of the flange 21a is eliminated.

When the forming of the corner edge 23 is completed, the upper mold 32 is raised with the rise of the ram of the press machine. When the upper mold 32 rises, the upper curved blade 61 also moves away from the outer plate 21. In this case, the valve connected to the air cylinder (not shown) is switched, and the cam 41 is moved by the air cylinder. Therefore, the contact between the cam 41 and the roller 39 of the mandrel 37 is avoided when the upper mold 32 is raised, and the mandrel 37 is kept pulled by the compression spring 40. Therefore, the metal core 37 does not swing toward the outer plate 21 unlike the lowering of the upper mold 32, and the corner edge 23 is not pressed by the metal core 37.

When the upper die 32 moves up and reaches the top dead center, the cam 41 is returned to a position where it can contact the roller 39 by the air cylinder.

[Effects of the Invention] According to the press die for corner hemming and the method for processing the edge hemming according to the present invention, the upper curved blade for pressing the front end of the flange portion of the outer panel against the inner panel to form the corner is provided with a corner. When the edge is formed, engagement means for engaging with the tip of the flange portion and pressing the vertical wall of the flange portion to a predetermined portion of the lower mold is provided, so that the vertical wall of the flange portion is prevented from falling inward. be able to.

Therefore, the vertical wall of the flange portion can be formed in a shape conforming to the shape of the predetermined portion of the lower die, and the corner can be formed into a shape as designed.

[Brief description of the drawings]

1 (a) to 1 (e) are cross-sectional views of a part of a hemming process using a press die for corner hemming according to the present invention, and FIG. FIG. 3 is a Bertle diagram showing the direction of the force acting on the flange portion when the edge is formed by the press die of FIG. 1, and FIGS. 4 (a) to (d) are the edge hemming according to the present invention. FIG. 5 is a front view showing the entire process of hemming processing by the press die for use in a rim, FIG. 5 is a front view showing the vicinity of a preliminary curved blade and an upper curved blade of the press rim for hemming in FIG. 7 (a) to 7 (d) are cross-sectional views showing each step of a conventional general hemming process, and FIG. 8 is a square edge formed. FIG. 9 is a cross-sectional view showing the vicinity of the outer peripheral portion of the outer panel. FIG. 10 (a) to (c) are cross-sectional views showing each step of hemming for forming the corners of FIG. 8, and FIG. 11 is a flange portion of the outer panel in FIG. FIG. 5 is a vector diagram showing directions of forces acting on. 21… Outer panel 21a… Flange 22… Inner panel 23… Square edge 31… Lower dies 32… Upper dies 37… Core bar 51… Preliminary curved blade 61… Upper curved blade 71… Means

Claims (2)

(57) [Claims] A lower die set in a state where an outer panel and an inner panel are superimposed, an upper die capable of ascending and descending with respect to the lower die, and a pad positioned between the upper die and the lower die. A core bar that is swingably supported, and a preliminary bend that presses a flange portion of the outer panel from the outside when the outer panel and the inner panel are pressed by the core bar, and folds the flange portion along the core bar toward the inner panel. A blade, an upper bent blade that presses a front end portion of the flange portion to the inner panel to form a square edge after the preliminary bent of the flange portion of the outer panel by the preliminary bent blade; Engaging means for engaging with the tip of the flange portion when the edge is formed by the blade and pressing the vertical wall of the flange portion against a predetermined portion of the lower die. Type. 2. A metal core is pressed against the inside of a flange portion of an outer panel which is set on a lower mold by being overlapped with an inner panel, and the flange portion is pressed from the outside by a pre-curved blade to form the core metal. Is preliminarily bent toward the inner panel side, and the core metal is retracted from the flange portion. Then, the pre-bending is performed by engaging the engaging means formed on the upper curved blade descending at the tip of the flange portion. The vertical wall of the flange formed by the above is pressed against a predetermined portion of the lower mold, and the front end of the flange is pressed against the inner panel by the upper curved blade to form a corner. Hemming processing method.