JPS6123046B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bending method and apparatus for performing preliminary bending, main bending, and hemming of a sheet metal work.

More specifically, the stopper of the pre-bending punch is used to pre-bend the sheet metal while preventing it from lifting up and deformation, and the final bending punch is moved diagonally at right angles to the hemming surface of the sheet metal to perform the final bending process, thereby bending the bent edge. A sheet metal bending method that achieves a good finish, improves appearance, and performs preliminary bending while applying pressure to the hemming surface of the sheet metal using a reverse push means, thereby making it possible to perform hemming with a good finished shape in addition to the above. and devices.

The hemming process in which the edge of one sheet metal is bent and fixed to the other sheet metal includes preliminary bending and final bending. Conventionally, in order to prevent deformation of the sheet metal during preliminary bending and final bending, a pressure force in the opposite direction to the bending direction is applied to the inner side of the hemming surface using a reverse pushing means, but this results in a large hemming angle. The more vertical the machined surface is, the more troublesome and difficult it becomes to create a reverse pressing structure.

A conventional example of a method of bending a sheet metal work using a preliminary bending punch and a main bending punch is shown in FIGS. 14 to 16, in which two sheets of metal sheets W ₁ and W ₂ are fixedly placed on a mold 50. Edge W ₁ a of one sheet metal W ₁ to be processed
is slightly bent, and the preliminary bending punch 51 is inserted into the 14th
As shown in FIG. 15, the edge W ₁ a is pre-bent by swinging, but as the punch 51 swings, the tip W ₁ b of the edge W ₁ a slides on the punch surface 51a. ,
Therefore, as shown in FIG. 15, the edge W ₁ a rises up from the mold 50 in a curved manner with a gap S therebetween, and in this state the preliminary bending is completed. The subsequent main bending was performed by moving the main bending punch 52 vertically downward as shown in FIG. 16, and even after the main bending, hemming was performed due to insufficient bending amount and bending angle due to preliminary bending. Deformation occurs in this part or other parts, and as the edge _W1a in Fig. 14 becomes vertical, the bending deformation shown in Fig. 15 occurs, and the punch 52 moves vertically to perform final bending. As a result, the hemming bending is insufficient, and a good linear bending shape cannot be obtained, resulting in a finished product with insufficient precision.

In view of the above-mentioned conventional problems, the present inventor has created the present invention in order to effectively solve the problems.

The purpose of the present invention is to prevent the sheet metal from curving and lifting during the preliminary bending process, to enable the sheet metal to be bent into a bent shape for preliminary bending, and to hem the punch without vertically moving the main bending punch during the main bending process. The final bending is performed by moving diagonally at right angles to the hemming surface, and the edge of the sheet metal is pre-bent into a bent shape.At the same time, the final bending punch is moved diagonally in the direction of the hemming surface, resulting in a straight bent edge. An object of the present invention is to provide a sheet metal bending method and an apparatus therefor, which can stabilize and improve bending accuracy.

In addition to the above, another object of the present invention is to pre-bend the hemming surface of a sheet metal while pressurizing it by a reverse pushing means that operates backward during the main bending process, so that the pressing force of the reverse pushing means is directly applied to the hemming surface. To provide a sheet metal bending method and an apparatus therefor, in which hemming at a bending angle of 180° can be easily performed by pre-bending while bending, and the hemming angle can be processed with a good parting edge and a large hemming angle. .

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the entire device according to the present invention, and FIG.
3 are diagrams showing the apparatus in accordance with the operating sequence from FIG. 1.

An upper die main body 1 is attached to the lower surface of an elevating member of elevating means such as a ram, and a slide base 2 is fixed to the main body 1. Slide the main bending punch 3 onto the base 2
The cam 4 for swinging the pre-bending punch is suspended and fixed to the base 2 so as to be slidable in the horizontal direction. The main bending punch 3 is resiliently biased in the rightward retreat direction in the figure by a spring 5 compressed and interposed between it and the cam 4, and the retreat position is regulated by a stopper 6. A main bending punch slide cam 7 that moves horizontally in synchronization with the main bending punch 3 is slidably provided on the slide base 2. A fixed cam 9 is set up on the lower die main body 8 which is fixed in a fixed position, and before the start of machining shown in FIG. 1, inclined cam surfaces 7a and 9a are provided on the vertically opposing cams 7 and 9 that are inclined in the same direction. Further, a swinging arm 10 is installed on the lower die main body 8 with its lower end pivotally connected to a shaft 10a so as to be able to swing back and forth, and is pushed upward by a spring 11 and a spring 12a installed between it and the fixed cam 9. arm 10 by push pin 12
be in an upright position under normal conditions. A preliminary bending punch 13 is attached to the top of this swing arm 10.

A limit switch 14 is attached to the fixed cam 9, and this switch 14 is operated by a dog 15 provided on the back surface of the pre-bending punch swinging cam 4. The lower die main body 8 is integrally formed with a workpiece pedestal 8a that protrudes upward, and two sheet metal workpieces W ₁ and W ₂ are placed between the die lower die 16 and the pedestal 8a installed at the top of the side of the pedestal 8a. Set.

A rod member 18 having a spring 17 wound thereon is suspended and supported from the upper mold body 1 so as to be movable up and down.
Attach the part body 19 to the lower end of the part 8. A front part 21 that holds a reverse push bar 20 so as to be able to slide freely in the horizontal direction and a rear holding member 22 are fixed to the lower part of the part main body 19, and the holding member 22 is connected between the reverse push bar 20 and the front part 21. The reverse push bar 2 is
0 is given a movement force in the backward direction. A cylinder 24 that is operated by an electric signal from the limit switch 14 is installed in the part body 19 facing downward, a reverse push cam 25 is provided on the rod 24a of the cylinder 24, and the cam 25 is inserted into the reverse push bar 20 to reverse the operation. Cam hole 20 for advancing the push bar 20
form a. The above-mentioned reverse push bar 20, cylinder 24, reverse push cam 25, etc. constitute a reverse push means.

A stopper 26 for preventing the workpiece from escaping is attached to the tip surface of the preliminary bending cam 13,
This stopper 26 is connected to the inclined first punch surface 1 of the pre-bending punch 13 as shown in FIGS. 4 to 6.
The vertical length is set so that the lower part protrudes somewhat from 3a.

Next, we will describe the operation of the device and the processing method based on it.

When the lifting means starts to descend from the raised state shown in FIG. 1 and the upper mold body 1 moves downward, first the parts 2
The lower surface of the spring 17 is in contact with the overlapped end 30 of the two sheet metal workpieces W ₁ and W ₂ on the side opposite to the hemming side ends, and the spring 17 is compressed by the continued downward movement of the upper die main body 1. Due to the elastic force, the parts 21 press against the end portions 30 to move the sheet metals W ₁ and W ₂ to the lower mold 16 and the workpiece pedestal 8a.
Position and fix on top. As the main body 1 continues to move downward, the rear dog 15 of the pre-bending swinging cam 4 operates the limit switch 14,
As a result, the cylinder 24 expands and the reverse push cam 25 moves the reverse push bar 20 between the sheet metal W ₁ and the reverse push bar 20 as shown in FIG.
The sheet metals W ₁ and W _{2 are moved forward in the direction W 2} , and the reverse push bar 20 presses the overlapping end portion 31 of the hemming process side of the sheet metals W 1 and W ₂ . The limit switch 14 is activated at the same time or with a slight time delay so that the cam 4 comes into contact with the back surface of the swing arm 10, and in the illustrated example, the front cam protrusion 4a of the cam 4
comes into contact with the roller-like cam 10b on the back surface of the arm 10, so that the arm 10 swings forward about the shaft 10a at the lower end as a fulcrum. As a result, the pre-bending punch 13, which similarly oscillates, pre-bends the edge _W1a of one of the sheet metal _W1 , and this pre-bending is performed by the counter push bar 2.
0 is performed while pressing the hemming surface of the sheet metal in the opposite direction to the bending direction.

When the cam protrusion 4a passes the roller-shaped cam 10b, the swinging arm 10 returns to its original upright position as shown in FIG.
4 is cut off, the reverse push bar 20 is moved by the spring 23.
It retreats due to the tensile force of the sheet metal, releasing the pressing force on the sheet metal. Next, as the upper mold body 1 continues to move downward, the main bending punch 3 finally bends the edge W ₁ a of the pre-bent sheet metal W ₁ , and this final bending process is performed on the cam surface of the cam 7 for the final bending punch slide. 7a and the cam surface 9 of the fixed cam 9
The main bending punch 3, which is integrated with the cam 7, comes into contact and sliding contact with the cam surfaces 7a and 9a, and the bending is performed while descending obliquely at the same inclination angle as the cam surfaces 7a and 9a, and the pressing force of the punch 3 bends the edge W ₁ a. is hemmed.

After the main bending process, the upper die body 1 which has reached its lowering limit is raised and returned to its original position, thereby completing one cycle of the process.

Detailed views of the preliminary bending and main bending processes performed in one step of lowering the elevating means as described above are shown in FIGS. 4 to 8. As shown in FIG. 4, the slightly bent edge W _{1 a} of the sheet metal W 1 to be bent is the first edge W ₁ a that is inclined toward the front of the pre-bending punch 13 due to the swinging.
Although it is pressed by the punch surface 13a and receives a pressing force, the fifth
As shown in the figure, since the stopper 26 is provided at the tip of the preliminary bending punch 13, the tip of the edge W ₁ a
W ₁ b is prevented from sliding on the first punch surface 13a and escaping from the pre-bending punch 13, and the stopper 26
By engaging the tip W ₁ b and applying a pressing force to the edge W ₁ a, the edge W ₁ a bends into a bent shape at the bending edge W ₁ c, and further the preliminary bending punch 13 swings. As a result, as shown in FIG. 6, the horizontal second punch surface 13b applies a pressing force to the edge W ₁ a, and the edge W ₁ a is further bent to increase the bending angle. The above-described preliminary bending is performed by applying a pressing force of the reverse pushing means to the hemming surfaces of the overlapping ends 31 of the two sheet metals W ₁ and W ₂ , so that the bending angle can be increased.

Main bending punch 3 replaced by preliminary bending punch 13
_The final bending process is performed by moving the final bending punch 3 diagonally in the _direction shown by the arrow in FIG. move and press the edge W ₁ a,
The edge portion W ₁ a is crimped to the edge portion W ₂ a of the other sheet metal W ₂ and fixed by clamping. In this way, the bending force is applied by moving the main bending punch 3 substantially perpendicular to the hemming surface, so that the hemming process direction and the main bending punch 3
The parting edge of the hemmed sheet metal is aligned with the moving direction of the hemmed metal sheet and is well finished in a straight line, resulting in a finished shape with stable precision.

FIG. 9 shows another embodiment of the reverse push means;
11 are diagrams shown in accordance with the operating sequence from FIG. 9. The same members as in the previous embodiment are given the same reference numerals.

A support member 40 is installed hanging down on the upper mold body 1, and two rods 4 each having a spring 41 wound around the support member 40.
2 and 42 to support the pad body 43.
A part 45 holding a reverse push bar 44 so as to be movable back and forth and a holding member 46 are attached to a part main body 43. Further, an arm-shaped reverse push cam 47 is positioned behind the reverse push bar 44 from the support member 40 and hangs down, and the reverse push cam 47 is pivotally connected to be swingable back and forth about a shaft 47a at the upper end as a fulcrum. A post 48 is erected on the lower die main body 8, and a reciprocating member 49, which is always urged in the projecting direction by a spring 49a, is incorporated into the post 48. The direction of the advancing/retracting member 49 is diagonally downward and forward.

As the upper die main body 1 descends, the back surface of the arm-shaped cam 47 comes into contact with the reciprocating member 49 as shown in FIG.
passes through the chamfered portion 49b of the reciprocating member 49 and swings about the upper end as a fulcrum, whereby the reverse push bar 44 is pushed forward by the arm-shaped cam 47 and pressurizes the hemming surface of the sheet metal. When the upper mold body 1 returns and rises, as shown in FIG. 13, the roller-shaped cam 47b passes through the front surface 49c of the advancing/retracting member 49, so that the advancing/retracting member 49 retreats by a certain amount, and the arm moves by the amount that the advancing/retracting member 49 retreats. The swing angle of the shaped cam 47 and the forward stroke of the counter-push bar 44 are reduced, and therefore the forward stroke of the counter-push bar 44 is reduced by the thickness of the bent edge W ₁ a of the sheet metal W ₁ . This makes it possible to return the reverse push bar 44 to its old position after completion of machining without interfering with the hemming surface.

In this way, the reverse pushing means can be configured as desired, and the cam means for swinging the preliminary bending punch and the cam means for moving the main bending punch diagonally are also arbitrary.

As is clear from the above description, according to the present invention, a stopper is provided at the tip of the pre-bending punch, and the end of the edge of the sheet metal to be bent is engaged with the stopper to prevent the sheet metal from escaping, thereby performing the pre-bending. As a result, preliminary bending is performed while preventing the edge of the sheet metal from lifting up in a curved manner, and the sheet metal can be bent into a bent shape without deforming the sheet metal. Furthermore, the main bending punch can be moved diagonally toward the hemming surface. Since the final bending process is performed at a straight angle, the pressing force of the final bending punch, which is approximately perpendicular to the hemming surface and coincident with the hemming process direction, allows the parting edge of the sheet metal to be finished in a good straight line, improving processing accuracy and appearance. It can be achieved.

Further, according to the present invention, since a reverse push means is provided that directly presses the hemming surface during preliminary bending, the bending amount and bending angle of the sheet metal can be reduced more than before by the pressing force in the opposite direction to the bending direction by this reverse push means. It is possible to increase the size, improve workability, and improve finishing accuracy.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are side views showing the entire device, and Figures 4, 5, 6, 7, and 8 are diagrams showing the operating order. Detailed drawings showing each process of preliminary bending and main bending, Fig. 9, Fig. 10,
Fig. 11 is a side view of a device employing another embodiment of the reverse push means, shown in the order of operation; Fig. 12;
13 are detailed views showing the operation of this other embodiment, and FIGS. 14, 15, and 16 are detailed views showing the conventional preliminary bending and main bending processes. In the drawing, 3 is a main bending punch, 4 is a cam for swinging the preliminary bending punch, 7 is a cam for sliding the main bending punch, 13 is a preliminary bending punch, 20 and 44 are reverse push bars, 26 is a stopper, W ₁ , W ₂ is the sheet metal, W ₁ a is the edge, and W ₁ b is the tip.

Claims (1)

[Claims] 1. Press the edge of the sheet metal with a moving pre-bending punch, and prevent the tip of the edge from escaping with a stopper at the tip of the pre-bending punch, position the sheet metal with the part, and reverse the process. Performing preliminary bending of the edge while pressing the hemming surface of the sheet metal in the opposite direction to the bending direction with a pressing means, then moving a final bending punch diagonally toward the hemming surface, and final bending the edge with the punch, A method for bending sheet metal using a press die, characterized by performing a hemming process. 2. A swingable pre-bending punch for pre-bending the edge of a sheet metal, a stopper provided at the tip of the punch and engaged with the tip of the edge during pre-bending, a lifting means and a cam means. A main bending punch that moves obliquely at a right angle to the direction of the hemming surface, a reverse push means that presses the hemming surface in the opposite direction to the bending direction during preliminary bending, and a sheet metal that holds the reverse push means slidably in the horizontal direction. A bending mold device using a press mold for sheet metal, characterized by comprising a part for positioning.