JPH03210916A - Press die for hemming - Google Patents

Abstract

PURPOSE:To prevent the outer panel from falling down and to improve a fineness in appearance of products by executing the 1st pre-bending with the 1st pre-bending blade and further executing the 2nd pre-bending with the 2nd pre- bending blade. CONSTITUTION:A flange part 21a is bent along a core metal part 37a, and the vertical wall of this flange part 21a is not fallen down, because this core metal 37 is positioned inside this flange part 21a of the outer panel 21 on the 1st pre-bending utilizing the 1st pre-bending blade 51. And on the 2nd pre- bending utilizing the 2nd pre-bending blade 71, the bending is applied toward the inner panel 22 side of the flange part 21a so as to press the vertical wall of the flange part 21a to the prescribed part of the lower die 31, so that the shape of the vertical wall of flange part 21a is made to follow the shape of the prescribed part of lower die 31 and the vertical wall is formed to the required shape. And when two pre-bending works are finished, the pre-bent top of the flange part 21a is pressed to the inner panel 22 with the upper bend ing blade 81 and the hemming work is finished.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a press die for hemming, and more particularly to a press die that suppresses the collapse of the vertical wall of the flange portion and the sag of the outer panel.

[Conventional technology]

BACKGROUND ART Hemming is a process in which two pressed products are fixed by bending the flange of one of the pressed products and sandwiching the other, for example, when manufacturing automobile bodies.

In general, the hemming process involves pre-bending the flange part and then bending the flange part to 180@.

Examples of devices for performing such hemming processing include, for example, Japanese Patent Application Laid-open No. 55-68133 and Mokai No. 59-3.
No. 9019 is known.

(A) to (2) of FIG. 14 show the procedure of conventional hemming processing. In FIG. 14 (a), the lower mold 11
An outer panel 1 is placed on the outer panel 1, and an inner panel 2 is placed on the outer panel 1. A flange portion 1a is formed on the outer periphery of the outer panel 1 and stands up at a nearly right angle. When the outer panel 1 and the inner panel 2 are placed on the lower die 11, the flange portion 1a is bent by nearly 45 degrees toward the inner panel 2 by the preliminary bending blade (buri blade) 13, as shown in FIG. 14(b). It will be done. When the bending of the flange portion 1a by the preliminary curved blade 13 is completed, the preliminary curved blade 13 retreats and the hem blade 14 descends toward the flange portion 1a, as shown in FIG. 14(c). Then, the flange portion 1a is pressed by the hem blade 14, and the outer peripheral portion of the inner panel 2 is sandwiched between the outer panel 1 and the outer panel 1 and the inner panel 2, as shown in FIG. 14(d). be integrated.

[Problem to be solved by the invention]

By the way, the hemming process is not limited to the shape shown in FIG.

FIG. 15 shows a body 3 made by a hemming press die that does not have a corner edge forming function, and FIG.
A vehicle body 4 formed by a press mold for corner hemming is shown. As shown in the figure, the formation of the corner edge 5 makes it difficult to see internal objects through the gap 6. In this way, corner edge hemming greatly contributes to improving the aesthetic appearance of pressed products.

FIG. 18 shows a hemming process for forming a corner edge. First, as shown in (A) of the figure, with the outer panel 1 and the inner panel 2 overlapped,
The outer panel 1 and the inner panel 2 are pressed together by a press-type core bar 15 shown in FIG. 17. At the same time, the preliminary curved blade 16 moves toward the flange portion 1a of the outer panel 1, and as shown in FIG. 18(B), the flange 1a is bent inward by the preliminary curved blade 16.

When the preliminary bending of the flange portion 1a is completed, the core bar 15 retreats, and then the upper bending blade 17 descends as shown in (c) in the figure, and the bending of the flange 1a is started. In this state, the vertical wall 1b of the flange 1a of the outer panel 1 is
It is in close contact with the outer peripheral portion 11a of No. 1. When the upper curved blade 17 descends, the flange portion 1a is bent downward and the corner edge 18 is formed, as shown in (d) of the figure. However, in this state, the upper part of the vertical wall 1b of the flange portion 1a is
As shown in FIG. 2, the lower die 11 separates from the outer circumferential portion Lla and falls inward and sag 12 occurs.
The shape of the corner edge 18 is not formed as designed, and the desired function cannot be achieved.

Figures 19(a) to 19(c) show the hemming process in which no corner edges are formed, and show the process when the inner panel 2 is thicker than the process shown in Figure 14. . ii! In normal hemming processing, as shown in Fig. 14, the preliminary bending of the flange portion 1a is performed without a core metal, so that the flange portion 1a after the bending process is completed.
The cross-sectional shape of the root part (vertical wall) of a is arcuate.If a press product with an arcuate end of the flange portion 1a is applied to the outer panel of a vehicle, etc., the appearance will be poor. Because of this problem, conventionally, the end portion of the flange portion 1a is hemmed with a hemming curved blade (upper curved blade) in the hemming and bending process.
The vertical wall was pressed down and corrected so that it was flat. However, as shown in Figure 19 (A), when the thickness of the inner panel 2' becomes large, as shown in Figure 19 (B) and (C), the outer panel 1 may be bent. The roundness of the edges becomes noticeable and cannot be corrected by pressing the hemming curved blade.

By the way, as shown in FIG. 20, a hemming curved blade (upper curved blade) is attached to the flange portion 1a of the outer panel 1 which has been pre-bent.
18, the end of the flange portion 1a has a force of N in the vertical direction and μN due to the frictional force between the curved blade and the edge of the panel.
occurs. In this case, the direction of the resultant force is the bending point Z
If the vertical wall 1b is always facing the base of the wall (m), the vertical wall 1b will not collapse.There are two methods to prevent the vertical wall from collapsing using this, but there are also problems that need to be solved. .

One of them is a hemming curved blade 19 as shown in FIG.
is to move toward the bending point Z. In this way, the vertical wall 1b of the flange portion 1a comes into close contact with the lower mold, and the vertical wall is prevented from falling down.

However, in this case, if the approach angle exceeds a certain angle, the second
As shown in FIG. 2, the inclined end surface 19a of the hemming curved blade 19
A problem arises in that the end surface of the flange portion 1a comes into contact with the end surface of the flange portion 1a, and the flange portion 1a is reversely bent as shown by the two-dot chain line.

The second method, as shown in FIG.
The purpose is to increase the sliding amount per unit stroke between the end of the flange portion 1a and the hemming curved blade 20 by changing the contact angle with the hemming blade 20, thereby increasing μN. However, in this case, since the lower surface 20b of the hemming curved blade 20 is not flat,
There is a problem that bending to the final shape cannot be performed as is.

In addition, as prior art related to the present invention, Japanese Patent Application Laid-Open No. 1-2
02319 is known.The edge bending device disclosed in this publication forms a corner edge using a core bar and a pre-curved blade. There is a problem in that this greatly limits the amount of energy available, which is disadvantageous in terms of product design.

In other words, in the case of this device, the preliminary bending blade and the upper bending blade are used in common, and the degree of freedom of movement thereof is small, so it is necessary to take a large preliminary bending angle during hemming processing. Therefore, if the space for the core metal to enter is the same, a large space must be taken from the edge of the outer panel to the rising part of the inner panel (reinforcing part raised by molding), which reduces the degree of freedom in product design. Put it away.

In addition, in the case of the device disclosed in this publication, the shape of the upper curved blade (pre-bending blade) is inevitably determined by the product shape, so when performing preliminary bending of the flange portion with the upper curved blade, the shape of the flange portion must be It becomes difficult to sufficiently press the vertical wall toward a predetermined portion of the lower mold.

Therefore, during preliminary bending, it becomes difficult to prevent the vertical wall portion of the flange portion from collapsing, and the state shown in FIG. 17(e) tends to occur.

Therefore, the present invention focuses on the above problem, and can prevent the vertical wall portion of the pre-bent flange portion from collapsing (that is, direct the resultant bending force toward the root portion of the vertical wall), and further, It is an object of the present invention to provide a press die for hemming which can reduce the bending angle when performing preliminary bending using a core bar.

[Means to solve the problem]

A press die for hemming according to the present invention that meets this purpose includes: a lower die that is inserted with an outer panel and an inner panel stacked together; an upper die that can be raised and lowered relative to the lower die; and the upper die and the lower die. A core bar is swingably supported by a pad located between the mold and the core bar, and when the outer panel and the inner panel are pressed by the core bar, the flange part of the outer panel is pressed from the outside and the flange part is moved along the core bar. The first pre-curved blade is used to pre-bend the core metal toward the inner panel side, and the flange portion which has been whitened by the first pre-bending blade after the core bar has been retreated is bent by the vertical wall of the flange portion into a predetermined position of the lower mold. a second pre-curved blade that pre-bends the flange portion of the outer panel toward the inner panel while pressing the portion; and an upper curved blade that presses the tip of the flange portion against the inner panel after the pre-bending portion of the flange portion of the outer panel is pre-bended by the pre-curved blade. Consisting of the following:

[Effect]

In the hemming press mold configured in this way,
A first preliminary bending of the flange portion of the outer panel is performed by the first preliminary bending blade. In the first preliminary bending, since the core metal is located inside the flange part, the flange part is bent along the core metal, and the vertical wall of the flange part does not fall.

In addition, in the case of the present invention, since the second preliminary bending blade further performs preliminary bending, it is possible to reduce the angle of the first preliminary bending by that much, thereby increasing the angle in the advancing and retreating direction of the core bar. Therefore, it is not necessary to secure a large space from the outer panel end to the reinforcing portion of the inner panel, and the degree of freedom in product design is not significantly restricted.

When the first preliminary bending is completed, the second preliminary bending of the flange portion is performed by the second preliminary bending blade. In the second preliminary bending, the flange part is bent toward the inner panel side so as to press the vertical wall of the flange part against a predetermined part of the lower mold, so the shape of the vertical wall of the flange part is The vertical wall is molded into a desired shape by imitating the shape of a predetermined portion of the mold.

When the two preliminary bending processes are completed, the tip of the pre-bent flange portion is pressed against the inner panel by the upper bending blade, and the hemming process is completed.

〔Example〕

Preferred embodiments of the hemming press die according to the present invention will be described below with reference to the drawings.

First Embodiment FIGS. 1 to 10 show a first embodiment of the present invention, and FIGS. 2 to 6 show the operation of each part of the press mold. In FIG. 1, a lower mold 311 is shown in the figure, and an outer panel 21 and an inner panel 22 are set on the lower mold 31. The inner panel 22 is placed on the upper surface of the outer panel 21. A vertically bent flange portion 21a is formed on the outer periphery of the outer panel 21. The bending point of the base of the press part 21a in this state is defined as zI.

An upper mold 32 is located above the lower mold 31.
2 is attached to a ram of a press machine (not shown). A plate-shaped pad 34 that can be raised and lowered is disposed between the upper mold 32 and the lower mold 31. On the bottom surface of the pad 34,
A pressure pad 35 is attached, and the middle pad 35 can come into contact with the lower die 31 side via the outer panel 21. A rod 33 extending upward is attached to the pad 34, and the rod 33 is movably inserted through the upper mold 32.

As shown in FIG. 1, the pad 34 is suspended from the upper mold 32 via the rod 33 when the upper mold 32 is at the top dead center.

A core metal 37 is located between the pad 34 and the upper mold 32. The core metal 37 is swingably supported by the pad 34 via a core metal locus variable mechanism 36, which will be described later.

The lower end portion of one side of the core metal 37 is a core metal part 37 that presses the flange part 2]a of the outer panel 21 and the inner panel 22.
It is formed in a.

The core metal trajectory variable mechanism 36 includes a link arm 38, 38' operating arm 4o, a first cam 45, a second cam 46, and a roller 47, 50. two link arms 38
．． 38' are parallel, and each link arm 3B, 3
The connecting portion 8' is a bottle connection. That is, in this embodiment, the pad 34, the core bar 37, and the two link arms 38, 38' constitute a parallelogram link mechanism. One link arm 38 of the two arms 38, 38' is connected to a column 34a of the pad 34 via a tension coil spring 39, thereby drawing the core bar 37 toward the pad 34. The link arm 3B' includes an actuating arm 40 having a fulcrum portion 48.
is swingably mounted.

A rotatable roller 47 is attached to the tip of the link arm 38'.
is installed. The link arm 38' is provided with a stopper 49 that can come into contact with the operating arm 40.
The actuating arm 4o can freely swing upward in the figure, and is prevented from swinging downward by coming into contact with a stopper 49.

A shock absorber 41 is attached to the upper surface of the pad 34 as a damping means. The tip of the rod of the shock absorber 41 can come into contact with a stopper 42 fixed to the link arm 38. The shock absorber 41 has a function of alleviating the impact acting on the core metal trajectory variable mechanism 36 that supports the core metal 37 when the core metal 37 is retreating, and for example, prevents the actuating arm 40 from jumping up due to the impact. It looks like this. On the top of the pad 34,
A stopper 43 is attached that contacts the link arm 38 and positions the core bar 37 during the first preliminary bending.

A cam driver 44 for driving the core metal 37 is attached to the upper mold 32 . A first cam 45 that can come into contact with a roller 47 attached to the operating arm 4o is formed on the side surface of the cam driver 44 on the side of the link arm 38'. When the roller 47 and the first cam 45 come into contact, the core metal 37 swings toward the flange portion 21a of the outer panel 21, and the core metal portion 37a contacts the inner wall surface of the flange portion 21a of the outer panel 21 and the inner panel. 22 is pressed.

In this embodiment, when the hemming process is completed and the upper die 32 is raised, the roller 47 and the first cam 45 come into contact again, but in this case, as shown in FIG. Since the arm 40 escapes upward around the fulcrum part 48, the core bar 37 does not interfere with the pressed product, and there is no problem in use. A second cam 46 for forcibly returning the core metal 37 is formed. This second cam 46
can come into contact with a roller 50 attached to the link arm 38 side. This second cam 46 and roller 50
constitutes a core metal return means. When the second cam 46 and the roller 50 come into contact, the two link arms 38
．． 38' swings, and the core bar 37 that has been pushed out diagonally downward is pulled back diagonally upward. In this embodiment, since the pressed product is large, the core metal 37 is supported via two sets of core metal locus variable mechanisms 36, as shown in FIG.

In this way, since the movement of the core metal 37 is controlled by the core metal trajectory variable mechanism 36 having a parallelogram link mechanism, the movement of the core metal 37 can be made smooth. In addition, the core metal return means is comprised of a second cam 4G and a roller 50.
However, it is also possible to use only the tension coil spring 39.

As in this embodiment, in a press die for forming a corner edge, unlike a general hemming process, a first preliminary curved edge 51,
A second preliminary curved blade 71 and an upper curved blade (hem blade) 81 are used. This is to ensure that the direction of the resultant bending force is directed toward the bending point Z1 when bending the flange portion 21a. These preliminary curved blades 51, 71 and the upper curved blade 81 are adapted to move as the upper die 32 moves.

The first preliminary curved blade 51 is attached to a holder (child cam) 52, and the holder 52 is swingably supported by a block 55 via two arms 53 and 54.

The two arms 53, 54 are parallel, and the connecting portion between the holder 52 of each arm 53, 54 and the block 55 is a pin connection. In other words, the holder 52, the block 55, and the two arms 53 and 54 constitute a parallelogram link mechanism. A guide roller 56 is attached to the arm 53. A driven body 58 in which a cam groove 57 is formed is attached to the block 55 . A tension coil spring 59 is connected to the arm 53, and the first preliminary curved blade 51 is urged in a direction away from the outer panel 21 by the tension coil spring 59. A stopper 55a that can come into contact with the arm 54 is fixed to the block 55.

On the other hand, a cam driver 60 for driving the first preliminary curved blade 51 is attached to the upper mold 32.

A cam 61 that can come into contact with the roller 56 is fixed to the lower end of the cam driver 60 . Cam driver 60 (7)
A cam 62 that performs forced return is fixed directly above the cam 61. When the roller 56 and the cam 61 come into contact with each other, the holder 52 swings toward the outer panel 21 and the first preliminary bending is performed.

FIG. 2 shows the first preliminary bending. As shown in FIG.
1 and the inner panel 22, the first preliminary curved blade 51
This is a bending process in which the flange portion 21a of the outer panel 21 is pressed from the outside and the flange portion 21a is bent toward the inner panel 22 along the core metal portion 37a.

A yoke main body 65 is swingably attached to the upper die 32 via a parallel link mechanism having two arms 63 and 64. The yoke body 65 has two arms 66.6.
A holder 68 is swingably supported via a parallel link mechanism having 7. The holder 68 is provided with a second pre-curved blade 71 for performing a second pre-bending process. The second preliminary curved blade 71 is capable of vertically sliding contact with an upper curved blade 81, which will be described later. The arm 6 is attached to the yoke body 65.
A stopper 69 that can come into contact with 6 is fixed. Rotatable rollers 72 and 73 are attached to the holder 68 side of the two arms 66 and 67. The upper die 32 includes a compression coil spring 74 that urges the yoke body 65 downward.
is provided.

A roller 75 is rotatably attached to the lower end of the yoke body 65.

As shown in FIG. 3, when the roller 75 attached to the yoke body 65 is in contact with the driven body 58, the yoke body 65 swings outward along the guide groove 58a, and the second
The lower surface of the pre-curved blade 71 contacts the end surface of the flange portion 21a, and the second pre-bending process is performed. As shown in FIG. 7, the bending surface 71a of the second pre-curved blade 71 is inclined at an angle α with respect to the horizontal plane. This is to direct the resultant bending force during the second preliminary bending to the bending point Z1.

B in FIGS. 4 and 7 shows the second preliminary bending. As shown in FIG. 0, the second preliminary bending is performed by the first preliminary bending after the core bar 37 retreats. The bent flange portion 21a is bent on the bent surface 71a of the second pre-curved blade 71.
This is a process of bending the vertical wall 21b of the flange portion 21a toward the inner panel 22 so that it is pressed against the stepped portion 31a of the lower mold 31 (that is, in such a manner that the resultant bending force is directed toward the bending point Z1).

The upper curved blade 81 is provided at the other end of the yoke body 65. As described above, one side surface of the upper curved blade 81 is capable of slidingly contacting the second preliminary curved blade 71 in the vertical direction. Second
When the preliminary bending process is completed and the upper die 32 is further lowered, the lowering of the second preliminary curved blade 71 is stopped due to contact between the stopper 82 and the roller 73, as shown in FIG. ing.

FIG. 4 shows a state in which the upper mold 32 has reached the bottom dead center,
In this state, the other ends of the two arms 66 and 67 forming the parallelogram link mechanism are lowered further than in FIG.
The upper curved blade 81 is configured to descend in an oblique direction toward the flange portion 21a of the outer panel 21. Thereby, the upper curved blade 81 presses the pre-bent flange portion 21a against the inner panel 22.

Next, the operation of the above hemming press die will be explained.

In FIG. 1, first, the outer panel 21 and the inner panel 22 are set on the lower mold 31. In this embodiment, a recess 21d is formed in the portion of the outer panel 21 to be pre-bent, as shown in FIG.

In this state, the upper die 32 is located at the top dead center.

When the outer panel 21 and the inner panel 22 are completely aligned, the ram (as shown) of the press machine is lowered, and the upper die 32 is lowered accordingly. In addition, in this state, the second preliminary curved blade 71 is located at position S0.

When the upper mold 32 is lowered, the pressure pad 35 attached to the lower surface of the pad 34 comes into contact with the upper surface of the outer panel 21, and the lowering of the pad 34 is stopped. Furthermore, upper mold 3
2 descends, the first cam 45 formed on the cam driver 44 comes into contact with the roller 47, and the core metal 37 swings diagonally downward toward the flange portion 21a of the outer panel 21, as shown in FIG. move.

Furthermore, when the upper mold 32 descends, the amount of swing of the core bar 37 becomes maximum, and the core bar 37a of the core bar 37 sufficiently covers the base of the inner wall surface of the flange portion 21a of the outer panel 21 and the outer circumference of the inner panel 22. Pressed with great force. Further, in this case, as shown in FIG. 2, the cam driver 60
The cam 61 and the roller 56 attached to the arm 53 come into contact with each other, the first preliminary curved blade 51 moves based on each cam plate, and the flange portion 21a of the outer panel 21 is moved by the first preliminary curved blade 51. A first pre-bending A is performed. As described above, the first preliminary bending is a bending process in which the flange portion 21a of the outer panel 21 is pressed from the outside by the first preliminary bending blade 51.
a is bent along the core metal part 37a. During the first preliminary bending, the second preliminary bending blade 71 is located at position S1, as shown in FIGS. 2 and 7.

When the first preliminary bending A of the flange portion 21a is completed and the upper mold 32 is further lowered, the first cam 45 and the roller 47
After the contact with the metal core 37 is completed, the core bar 37 is moved as shown in FIG.
It is returned to its original position by a tension coil spring 39. At this time, the shock absorber 41 reduces the impact when returning. In this case, the core metal part 37a is returned without interfering with the bent flange part 21a. Further, in this case, the roller 56 attached to the arm 53
Then, the contact with the cam 61 formed on the cam driver 60 for driving the first preliminary curved blade 51 is completed, and the first preliminary curved blade 51 retreats in the direction away from the flange portion 21a.

When the retreat of the core metal 37 is completed, the upper die 32 further descends, the roller 75 comes into contact with the guide groove 58a of the driven body 58 attached to the lower die 31, and the yoke body 65 swings outward. do. When the yoke main body 65 swings, the second pre-curved blade 71 moves toward the end face of the flange portion 21a as shown in FIG. Pre-bending B is performed. At the start of the second preliminary bending B, the second preliminary bending blade 71 is located at position S in FIG.

As described above, in the second preliminary bending B, the flange portion 21a bent by the first preliminary bending is bent by the second preliminary bending surface 71a so that the vertical wall 21b of the flange portion 21a is bent at the stepped surface of the lower die 31. This is a bending process in which the flange portion 21a is bent toward the inner panel 22 side so as to be pushed by the flange portion 31a, so that the bent flange portion 21a becomes almost horizontal. When the second preliminary bending is completed, the second preliminary bending blade 71 is located at S in FIG.

In this way, during the second preliminary bending, the locus of the second preliminary bending edge can be set in a specific downward diagonal direction so that the direction of the resultant bending force is the bending point Z1, so that the bending surface 7
The contact angle β between 1a and the end face of the flange portion 21a can be maintained at an optimal angle, and the vertical wall 21b of the flange portion 21a
can be sufficiently pressed against the stepped surface 31a of the lower die 31. Therefore, the shape of the vertical wall 21b of the flange portion 21a follows the step surface 31a of the lower mold 31, and is prevented from falling inward.

When the second preliminary bending is completed, the second preliminary curved blade 71 is
The lowering is completed by the contact between the roller 73 and the stopper 82. Then, the second preliminary curved blade 71 moves laterally as shown in FIG. 4 when the roller 75 enters the guide groove 58a of the driven body 58.

At the same time, the upper curved blade 81 opens the flange portion 2 from diagonally above.
1a, the pre-bent flange portion 21a is pressed by the upper curved blade 81, as shown in FIG.
A corner edge 21C is formed. Since the upper curved blade 81 descends in a substantially oblique direction, also in this case, the vertical wall 2 of the flange portion 21a
1b comes to be pressed against the step surface 31a of the side plate of the lower mold 31, and the problem of the flange portion 21a being bent inward from the lower end is also solved.

As described above, in this embodiment, since the preliminary bending of the flange portion 21a is performed by the first preliminary bending and the second preliminary bending, the flange portion 21a during the first preliminary bending is
There is no need to secure a large bending angle, and there is no need to secure a large space for moving the core bar 37 forward and backward.

Therefore, the distance from the end of the outer panel 21 to the raised reinforcing portion 22a of the inner panel 22! , can be made shorter, increasing the degree of freedom in product design.

Furthermore, by making the second preliminary bending independent, it becomes more reliable to set the direction of the resultant bending force when bending the flange portion 21a toward the bending point Z.

Note that it is technically possible to provide a first pre-bending section and a second pre-bending section on one pre-curved edge, but in this case, the trajectory of the pre-curved edge can be controlled. The cam mechanism used for this process becomes complicated, and the stroke of the press mold during molding becomes large, which greatly limits the number of press machines that can be used.

Second Embodiment FIGS. 11 to 13 show a second embodiment of the present invention. In the first embodiment, an example of hemming processing in which a corner edge is formed was shown, but in this embodiment, a corner edge is not formed and the hemming processing is performed when the thickness T of the inner panel 22 is larger than that of the outer panel. An example is shown.

As shown in FIG. 19, if the inner panel is thick, the edges of the outer panel after hemming will be rounded, which may impair the aesthetic appearance of the vehicle. A press mold to prevent this as much as possible even when the panel thickness is large will be described.

The configuration of this embodiment is based on the first embodiment, so the explanation of the corresponding parts will be omitted by giving the same reference numerals as in the first embodiment, and only the different parts will be explained.

In FIG. 11, 37a indicates a core metal portion.

A protrusion 37b is formed at the tip of the core metal portion 37a. The protrusion 37b protrudes downward by the thickness of the inner panel 22. The front end surface of the projection 37b is a vertical surface 37C as shown in FIG.

The first pre-curved blade 51 has a bending surface 51a for performing the first pre-bending A, and the second pre-curved blade 71
has a bending surface 71a for performing the second preliminary bending B.
It has The upper curved blade 81 has a flat lower end surface 81a.

In the second embodiment configured in this way, as shown in FIG. 11(a), the outer panel 21 and the inner panel 22 are pressed by the core bar 37a. In this state, the protrusion 37b of the core metal part 37a is brought into contact with the corner part of the flange part 21a of the outer panel 21.

Next, as shown in (b) of the figure, the flange portion 21a is pressed by the bending surface 51a of the first pre-curved blade 51, and the first pre-bending A is performed. In this case, since the flange portion 21a is bent from the upper end C of the protrusion 37b shown in FIG. 12, the flange portion 21a is prevented from falling down from its base. When the first preliminary bending A is completed, the core bar 37a is retracted and the first preliminary curved blade 51
will also be set back. When the core metal part 37a is completely retracted, the second
A second preliminary bending B of the flange portion 21a is performed by the bending surface 71a of the preliminary curved blade 71. In this case, the vertical wall 21b of the flange portion 21a is bent while being pressed against the stepped portion 31a of the lower mold 31 by the second preliminary curved blade 71.

Therefore, the vertical wall 21b does not fall inward with respect to the stepped portion 31a of the lower mold, as shown in FIG. 13.

When the preliminary bending shown in FIG. 13 is completed, the second preliminary curved blade 71
moves backward, the flange portion 21a is pressed against the inner panel 22 by the upper curved blade 81, and the hemming process is completed. In this state, the end portion of the outer panel 21 is
The vertical wall 21b of the flange portion 21a has the shape shown in e).
The perpendicularity is significantly improved compared to the conventional shape shown in FIG. 19(C).

〔Effect of the invention〕

As explained above, when using the hemming press die according to the present invention, the first preliminary bending is performed by the first preliminary bending blade, and the second preliminary bending is performed by the second preliminary bending blade. Therefore, the hemming process can be performed without causing the vertical wall of the outer panel to collapse, and the aesthetic appearance of the pressed product can be improved.

In other words, when bending the flange portion, it becomes possible to direct the bending force as much as possible to the root portion (bending point) Z, of the vertical wall, and it is possible to reliably prevent the vertical wall from collapsing.

In addition, since the preliminary bending process can be performed in two steps, the bending angle during the first preliminary bending using the core metal can be reduced, and the space required when moving the core metal back and forth can be reduced. be able to.

Therefore, the distance from the end of the outer panel to the rising portion (protruding reinforcing portion) of the inner panel can be shortened, and the degree of freedom in product design can be increased.

Since the first pre-curved blade and the second pre-curved blade are not shared and move independently, it is possible to minimize unnecessary relief, and the press die processing stroke can be kept small. I can do it. Therefore, it can be applied to many press machines, and operability is improved.

[Brief explanation of drawings]

FIG. 1 is a front view of essential parts of a press die for hemming according to a first embodiment of the present invention, FIGS. 2 to 6 are front views showing hemming processing using the press die of FIG. 1, and FIG. is a cross-sectional view showing the movement of the second preliminary curved blade and the upper curved blade in the press die shown in Figure 1, Figure 8 is a plan view of the variable core trajectory mechanism in Figure 1, and Figure 9 is before hemming. FIG. 10 is a cross-sectional view of the outer plate after hemming processing; FIG. 11 (a) to e) are cross-sectional views showing hemming processing using a hemming press die according to the second embodiment of the present invention. Figure 12 is a partial enlarged cross-sectional view of Figure 11 (A), Figure 13 is a partial enlarged cross-sectional view of Figure 11 (C), and Figures 14 (A) to 2) are of the conventional press mold. A cross-sectional view showing each step of the hemming process. Figure 15 is a cross-sectional view of a vehicle body formed by a hemming press die that does not have a corner edge forming function. Figure 16 is a cross-sectional view of a vehicle body formed by a corner edge hemming press die. Figure 17 is a front view of the main parts of a conventional hemming press die; Figures 18 (a) to (e) are cross-sectional views showing each step of the hemming process for forming corner edges; Figures 19 (a) to c) are cross-sectional views showing each step of hemming in which no corner edges are formed; Figure 20 is a cross-sectional view showing the principle of press working to prevent the vertical wall of the flange portion from collapsing; 21 and 22 are sectional views showing the specific example of FIG. 20, and FIG. 23 is a sectional view showing another specific example of FIG. 20. 21... Outer panel 21a... Flange portion 21b... Vertical wall 22... Inner panel 31... Lower mold 32...・Upper mold 34...Pad 36...Core metal locus variable mechanism 37...Core metal 38.38'...Link arm 40...
...Operating arm 41...Impact mitigation means 45...First cam 46...Second cam 47.50...Roller 51... ...First pre-curved blade 71...Second pre-curved blade 81...Upper curved blade A...First pre-bended B... -Second preliminary bending Z.・・・・・・Bending point patent applicant Toyota Motor Corporation Kuro 3 ■ 32 Figure 4 Figure 5 Figure 5 Figure 6 2 50 Figure 7 MO Figure 8

Claims (1)

[Claims] 1. A lower mold set with an outer panel and an inner panel stacked together, an upper mold that can be raised and lowered with respect to the lower mold, and a position between the upper mold and the lower mold. a core metal that is swingably supported by a pad that presses the outer panel and the inner panel, and a flange portion of the outer panel is pressed from the outside when the core metal presses the outer panel and the inner panel, and the flange portion is moved along the core metal toward the inner panel side. A first pre-curved blade to be bent, and a flange portion bent by the first pre-curved blade after the core bar retreats, and the vertical wall of the flange portion is pressed against a predetermined portion of the lower mold while pressing the inner panel. A second pre-curved blade that pre-bends the flange portion of the outer panel to the side, and an upper curved blade that presses the tip of the flange portion against the inner panel after the pre-bending portion of the flange portion of the outer panel is pre-bent by the pre-bending blade. Features a press die for hemming. 2. A lower mold set with an outer panel and an inner panel stacked on top of each other, an upper mold that can be raised and lowered relative to the lower mold, and a pad located between the upper mold and the lower mold that is swingable. a core metal supported by and capable of pressing the outer panel and the inner panel; and a plurality of curved blades, at least one of which works in cooperation with the core metal to bend a flange portion of the outer panel toward the inner panel side. A hemming press die comprising: a link arm connecting the core metal and the pad; an operating arm swingably attached to the link arm and having a roller at its tip; a first cam that can come into contact with the roller of the arm; and a first cam that is attached to the link arm, and when the first cam comes into contact with the roller of the operating arm, restricts the movement of the operating arm relative to the link arm and tilts the cored metal. A stopper that pushes downward,
A press mold for hemming, comprising: a core metal return means for pulling back the core metal pushed out diagonally upward; and a core metal trajectory variable mechanism for changing the trajectory of the core metal. 3. A lower mold set with an outer panel and an inner panel stacked on top of each other, an upper mold that can be raised and lowered relative to the lower mold, and a pad located between the upper mold and the lower mold that is swingable. a core metal supported by and capable of pressing the outer panel and the inner panel; and a plurality of curved blades, at least one of which works in cooperation with the core metal to bend a flange portion of the outer panel toward the inner panel side. A hemming press die comprising: a link arm connecting the core metal and the pad; an operating arm swingably attached to the link arm and having a roller at its tip; a first cam that can come into contact with the roller of the arm; and a first cam that is attached to the link arm, and when the first cam comes into contact with the roller of the actuating arm, restricts the movement of the actuating arm with respect to the link arm, and causes the core bar to move diagonally. A stopper that pushes downward,
a core metal return means for pulling back the core metal pushed out diagonally upward; a core metal trajectory variable mechanism for changing the trajectory of the core metal; and a core metal trajectory variable mechanism for changing the trajectory of the core metal when the core metal moves back. A press mold for hemming, characterized in that it is equipped with an impact mitigation means for mitigating the impact acting on the mechanism, and.