JPH02247019A - Press-forming method - Google Patents

Abstract

PURPOSE:To prevent a defective from occurring by making the widths of a punch and a die variable, providing inclinations having an expecting angle exceeding a vertical angle each on the sides of them, and giving a side pressure to the die to press a material to be worked to the punch. CONSTITUTION:A U-shape bending is carried out by a press. Then, the punch is composed of a punch holder 8, a width deciding plate 4 and a segmental punch 12, and the width is made variable. The die 18 is mounted on a die holder 13 so that its width is variable. The inclinations having an expecting angle exceeding a vertical angle each are provided on the sides of segmental punches 12 and segmental dies 18. Further, a side pressure is given by a hydraulic cylinder 20 to the die 18 during operation to press a material to be worked to the punch. By this method, the precision of the bending angle can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a press forming method with high processing accuracy, in which various types of U-shaped bent products having different bending widths are formed in a single die.

[Prior Art] In conventional U-shaped bending, as shown in FIG. A dedicated mold was prepared for each product, or the shims S between each insert and the holder were replaced.

[Problems to be Solved by the Invention] In the conventional work described above, a large number of man-hours are spent on setup, and the bending angle of the punch must be 90° or more due to the structure, so products with a bending angle of 90' are required. In order to achieve this, it was necessary to adjust the cushioning pressure to prevent the angle from increasing due to springback.

[Means for solving the problems] In view of the above-mentioned circumstances, in order to solve these problems, the present invention makes the punch width and die width variable in U-shaped bending by press, and The side surfaces of the punch and die are sloped with a viewing angle exceeding vertical, and lateral pressure is applied to the die during processing to press the workpiece against the punch. This product is provided for the purpose of reducing adjustment time, reducing set-up, and improving machining accuracy by allowing the bending product to be handled with a mold, and by taking the amount of springback into the mold shape.

[Embodiment] Next, an embodiment of the press molding apparatus according to the present invention will be described based on the drawings.

Reference numeral 1 denotes an upper mold holder formed into a rectangular shape, and a ram is attached to a plate 2.

Further, on the left and right lower sides of the upper die holder 1, corresponding kite plates 3, 3 are provided, and holes 6 are provided in the center thereof for inserting the upper portions of positioning pins 5 provided on punch width determining plates 4, which will be described later.

A pair of guide pins 7.7 are fixed to the corresponding guide plates 3, 3 horizontally at an interval, and a pair of divided punch holders 8,
8 is slidably fitted and guided so that it can be moved by the action of an air cylinder 9, which will be described later.

Further, the punch holders 8, 8 are provided with four parts 10.11 at the upper and lower parts of the opposing inner surfaces, and the upper plate 4a provided on the positioning pin 5 from the width determining plate 4 is locked in the recessed part 10 at the upper part. to support the width determining plays 1 to 4, and place the upper part of the dividing punch 12. It is installed with 1- etc.

The air cylinder 9 is attached to one side of the punch holders 8, 8, and the tip end of the screw 1 to the screw 9il from the air cylinder 9 is attached to the other side, so that the punch holders 8, 8 are opened and closed by the operation of the air cylinder 9. This makes it possible to accommodate any web width. That is, split punch 12.12
The width of the punch is determined by interposing the width determining plate 4, the upper plate 1-4a, and the positioning pin 5, and the width of the punch is obtained by tightening the air cylinders 9 of the punch holders 8, 8. Therefore, by exchanging the width determining plates 4, 4, a punch width of 0.5 mm can be obtained.

Reference numeral 13 designates a die holder on the polster 14, which is provided with rising side plates 13a, 13a facing each other on the left and right, and has a through hole 16 in the center for guiding the pin 15a of the cushion pad 15, and a recess 17 into which the cushion pad 15 is fitted. It is. Also, the side plate 13a
, 13a are provided with lateral guide holes 1.9.19 at intervals.
A guide pin 18a, 1.8a from a pair of opposing dies 18.18 sliding on the die holder 13 is inserted therethrough to guide the movement of the dies 18.18. In addition, hydraulic cylinders 2 are installed in the side plates 13a and 13a in the lateral direction, respectively.
0.20 is installed, and the tips of the piston rods 20a, 20a of this hydraulic cylinder 20°20 are connected to the die 18.18.
It is designed to apply lateral load by attaching it to the That is, die 1
8.18 is to be pressurized.

Further, an extrusion spring 21 is interposed between the hydraulic cylinder 20 and the die 18, and the die 18 is constantly pushed by the spring 21 and extruded so as to be closed.

Further, the inner surfaces of the upper die punch 12 and the lower die are provided with slopes C and C, respectively, which are springback angles of view.

Furthermore, the upper die holder 1 is attached by attaching a plurality of hydraulic cylinders 22 for generating oil pressure downwardly at intervals on the plate 2,
An extrusion spring 23 is applied to the screws 1 to 22a from the hydraulic cylinder 22, so that they are always extruded when the ram is raised.

Fig. 8 shows a hydraulic circuit, where 24 is a sea fence valve, 25 is an oil tank, and 26 is a cylinder used to open the die 18 and 18 for stage change or to bleed air from the hydraulic cylinder 20 using air sent from the factory. When returning the cylinder, use the return side port 1 of the cylinder.
It is designed to flow into ~.

[Function] As is clear from the above configuration, in the present invention, when performing U-shaped bending of a workpiece, first the punch width is determined. In this case, the split punch 12.
Insert the width determining plate 4 and the positioning pin 5 between the holes 12 and 12, insert the positioning pin 5 into the hole 6 provided in the center of the upper mold holder 1, and insert the upper plate 1-4 into the punch holder 8.8.
After positioning is performed by engaging the upper recess 10 of the split punch 12, 12, the split punch 12, 12 is pressed against the width determining plate 4 by the air cylinder 9. Further, the lower mold dies 18, 1.8 are positioned between the dies 18.18 by the extrusion spring 21 toward the stopper. In this case, the width of the stopper is made to be slightly narrower than the processing width of the workpiece W. Also, the workpiece W
is placed on the cushion pad 15 lifted by the cushion force, and in this state the punch 12.12 is lowered by the ram and bending is performed in the same way as normal forming, but at this time the die 18.18 is stopped by the stopper. Since it is positioned slightly narrower than the width, it is pushed open by the punch 12° 12 and the workpiece W and moves, pushing the hydraulic cylinder 20. As a result, the pressure inside the hydraulic cylinder 20 increases and a reaction force is generated.

Further, when the punch 12.12 descends, the tip of the piston rod 22a of the hydraulic cylinder 22 for generating hydraulic pressure hits the polster 14, and when the piston rod 22a is pushed, the hydraulic pressure inside the hydraulic cylinder 22 rises rapidly and is supplied to the hydraulic cylinder 20. A lateral load acts, and the workpiece W is completely sandwiched between the punch 12.12 and the die 18.18, and until the bottom dead center, the oil in the circuit flows back to the tank 25 by the sea fence valve 24 at a constant rate. Pressure is maintained.

Also, since the die 18 and the punch 12 are provided with a viewing angle, the width of the die 18.18 must be reduced, but the pressure generated by the hydraulic cylinder 22 for generating hydraulic pressure is supplied to the hydraulic cylinder 20 as described above. This allows the desired bending angle to be obtained.

[Effect] As described above, the present invention makes the punch width and die width variable in U-shaped bending using a press, and also provides slopes with a prospective angle exceeding vertical on the side surfaces of the punch and die, and furthermore, during processing. This press forming method is characterized by applying lateral pressure to the die to press the workpiece against the punch, and the punch is divided into parts and U-bending can be performed with different bending widths by simply replacing the width determining plate. As a result, one mold can be used to reduce the total number of press molds and setup time, and the amount of springback can be taken into account in the mold shape to ensure the accuracy of the press bending angle. This eliminates the need for adjusting the comb pressure, which is normally performed, and has the effect of reducing adjustment time and preventing the production of defective products due to adjustment errors.

[Brief explanation of drawings]

The drawings show one embodiment of an apparatus for a press forming method according to the present invention, in which FIG. 1 is a longitudinal sectional front view of a conventional press bending apparatus, and FIG. 2 is a longitudinal sectional front view of a press forming apparatus according to the present invention.
Figure 3 is a front view of a part during bending, Figure 4 is a front view during bending, Figure 5 is a back view with a part of the upper mold cut away, Figure 6 is a plan view of the lower mold, FIG. 7 is a perspective view of the width determining plate, and FIG. 8 is a hydraulic circuit diagram for generating a die lateral load. Plate 5 ~ Positioning pin 6 ~ Insertion hole 7 ~ Guide pin 8 ~ Punch holder 9 ~ Air cylinder 9a
~ Piston Rondo 10.11. ．． 17~Recessed part 12~Divided punch 13~Die holder 13a~Rising side plate 1
4~Polster 15~Cushion pad i5a~Pin 16~Through hole 18~Die 18a~Guide pin 20~
Hydraulic cylinder 20a ~ piston rond 21.23
~Extrusion spring 22~Hydraulic cylinder for generating oil pressure)j
22a ~ Piston Rondo 24 ~ Sequence 2
5 ~ Oil tank 1 ~ Upper mold holder 2 ~ Mounting plate 3 ~ Guide plate
4 ~ Width determining plate 4a ~ Upper part Figure 5 Figure 4 Figure 4, j''' drawing cancer Z diagram

Claims (1)

[Claims] In U-shaped bending using a press, the punch width and die width are made variable, and the sides of the punch and die are provided with an inclination with an angle of view exceeding vertical, and lateral pressure is applied to the die during processing. A press forming method characterized by pressing the material against a punch.