JP3131284B2 - Work bending method and press brake used in the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of bending a work and a press brake used in the method.

[0002]

2. Description of the Related Art Various types of work bending angle measuring means for measuring a bending angle of a work bent by a press brake, for example, as a bending apparatus have been known.

First, there is known a means for measuring a work angle with a CCD camera.

[0004] Secondly, there is known a means for removing a work in process from a punch and a die as a mold and measuring the bending angle of each part of the work by an operator.

Thirdly, there is known a means for inserting a work bending angle measuring device between a plurality of divided dies for measuring a bending angle.

Fourthly, there is known a means for detecting a bending angle by providing a protruding pin type sensor in a V groove of a die.

[0007]

By the way, of the above-mentioned conventional work bending angle measuring means, the first means is:
The bending angle at both ends of a long work can be measured, but the bending angle at the center cannot be measured. Therefore, there is a problem that it cannot be determined whether or not the work is uniformly bent in the longitudinal direction.

Next, the second means has a problem that the work is frequently taken in and out of the mold, which is dangerous, and is time-consuming and inefficient because the measurement is performed by an operator.

In the third means, since a gap for measuring the bending angle is provided between the dies, the work cannot be partially held between the punch and the die in the gap during bending. There is a problem in that the bending angle is different from other portions and becomes sweet, and indentations due to pressurization are generated, thereby deteriorating the quality of the work.

Further, in the fourth means, measurement can be performed only at the V-groove width portion of the die. However, since this portion is where R is formed at the corner of the bent work, accurate measurement is performed under the influence of this R. There is a problem that it is difficult to measure a bending angle.

In view of the above-mentioned various problems, the present invention can measure the bending angle of the central portion of a long work, is efficient and safe for an operator, and has a variation in the thickness of the work. Another object of the present invention is to provide a press brake which can measure an accurate bending angle without being affected by the bending R.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems.
In a method of bending a work by a punch and a die as upper and lower dies in a press brake, the work is bent by the punch and the die, and after holding in a state where a springback occurs, a plurality of work pieces are previously formed. The divided dies are moved in the left-right direction to form a gap between each of the divided dies, and a bending angle measuring device faces the lower side of the work from the gap to lower the bending angle of the work from the lower side. This is a work bending method in which the work is bent again by the punch and die in order to correct the bending angle after closing the gap after measurement.

According to a second aspect of the present invention, there is provided a press brake having an upper table provided with a punch and a lower table provided with a plurality of dies divided in the left-right direction. A work bend angle measuring device is provided so as to be capable of forming a gap between the dies, and the work bend angle measuring device capable of freely facing the lower side of the work from the gap in order to measure a bending angle of the work from below at a position corresponding to the gap. This is a configuration provided for the lower table.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the relationship between the entire press brake 1 and the work bending angle measuring device 3 will be described with reference to FIG. A ram 7 is provided on the upper front surface of the left and right side frames 5 erected on the floor G so as to be vertically movable by a hydraulic device 9, and a lower table 11 is provided on the lower front surface of the side frame 5 on the floor surface. It is provided on G. The lower part of the ram 7 is provided with a punch 1 as an upper die via an attachment member 13.
5 is provided with the processing surface facing downward, and on the lower table 11, a die 17 divided into a plurality as a lower mold is provided via a slide base 19 with the processing surface facing upward. Therefore, the bending process is performed by pushing the ram 7 downward while clamping the work W by the cooperation of the punch 15 and the die 17.

The lower table 11 is provided with notches 23 for accommodating the workpiece bending angle measuring device 3 at a plurality of positions (two positions in this embodiment) in the left-right direction. The work bending angle measuring device 3 is provided with a lifting cylinder 27 having a piston rod 25, and a base bracket 29 is provided on the upper end of the piston rod 25 so as to be vertically movable. The base bracket 29 is provided with an X-link type detector 31.

The work bending angle measuring device 3 raises the piston rod 25 of the elevating cylinder 27 only when measuring the bending angle of the work W, so that the tip of the X-link type detecting tool 31 is attached to the work W. Make contact. Therefore, the die 17 is divided into a plurality of parts (three in this embodiment) in the left-right direction, and the piston rods of the slide cylinders 33 provided on the left and right slide bases 19 are used only when the bending angle of the work W is measured. By contracting 35, gaps 37 appear between the dies 17. The slide base 19 is originally divided into a plurality of parts, and is fixed on the lower table 11 with a gap 39 so that the workpiece bending angle measuring device 3 can be moved up and down.

The details around the die 17 will be described with reference to FIG. First, a slide base 19 is fixedly provided on the lower table 11. A long groove 41 extending in the left-right direction is provided on the lower surface of the slide base 19, and a die 17 is provided in the inner groove of the slide base 19 so as to be movable left and right. An appropriate number of bolts 43 are provided on the lower surface of the die 17 via the spacer 45 so that the die 17 does not protrude upward.
1 is tightened from below. Further, the spacer 45
Is provided in the bottom of the long groove 41 of the slide base 19 so as to be movable left and right in a long hole 47 extending in the left and right direction. On the other hand, a work lifter 51 extending left and right is urged upward via a sprink 53 in a long groove 49 which opens upward in the die 17 and extends in the left and right direction. At the upper part of the work lifter 51, a V-groove 55 is provided extending in the left-right direction to engage with the shape of the lower end of the punch 15.

A control device 57 is provided on the floor G near the press brake 1, as shown in FIG. The control device 57 includes an A / D conversion device 59 for converting the analog electric amount transmitted by the work opening amount detection means 21 into a digital signal, and an average of a plurality of measurement angles converted into the digital signal. An arithmetic unit 61 for obtaining a value, and a control unit 63 for comparing the average value of the measured angles with a desired bending angle and instructing the hydraulic device 9 of an appropriate ram plunging amount are provided.

Next, the details of the X-link type detector 31 will be described with reference to FIGS. However, in this embodiment, an example in which measurement can be performed at two places in the width direction of the work W will be described.

First, a short arm X link 65 has a lower portion pivotally supported by a fixing pin 67 supported by the base bracket 29, and a first short link 69, and a central portion of the first short link 69. The second short link 73 swingably supported by the center pin 71 provided in the pair is provided in a pair in an X shape. Above the first and second short links 69 and 73,
A roller-shaped contact 75 for measuring the bending angle by contacting the workpiece W is provided at the tip of each of the arms bent inward. A slider 77 is provided at the lower end of the second short link 73.

A meter case 79 fixedly provided below the first short link 69, a potentiometer 81 as a resistor provided in the meter case 79, and both ends of the potentiometer 81 are electrically connected. A battery 83, a minus terminal 85 connected to the minus pole of the battery, the slider 77 slidingly contacting the potentiometer 81, and electrically connected to the slider 77. A plus terminal 87 is provided.

When the base bracket 29 of the work opening amount detecting means 21 rises, it is desirable that the short arm X-link 65 comes up in a contracted state. For this purpose, a center spring 89 is provided to pull the lower portions of the first and second short links 69 and 73 inward to urge them.
Further, when the base bracket 29 is lifted, the side springs 91, which are weaker than the center spring 89, are provided on both sides of the center spring 89 so that the short arm X-link 65 rises at an appropriate angle without falling down.
93 are provided. These side springs 91, 9
The other end of 3 is swingably supported by fixing pins 95 and 97 supported by the base bracket 29.

Next, on the right side (the back side in FIG. 1) of the short arm X link 65, a long arm X link 65L
1 are provided coaxially. However, the pipe-shaped spacers 99 are provided so as to keep a constant interval so as not to interfere with each other. Upper portions of the first long link 69L and the second long link 73L of the long arm X link 65L are longer than the first and second short links 69, 73, and the short arm X link 6 is provided.
5, except that the angle measurement of the part of the work W on the front and rear side (further outer side in FIG. 1) is enabled.
The configuration is the same as that of the short arm X link 65. Also, since the configuration of the work opening amount detecting means 21L below the meter case 79L attached to the lower part of the first long link 69L is the same as the configuration below the meter case 79, the components related to the long arm X link 65L. In the figure, the same numbers and suffixes L as those of the corresponding components in the short arm X link 65 are given in the figure, and the description is omitted.

The operation of this embodiment will be described with the above configuration. First, the piston rod 3 of the slide cylinder 33
5 is protruded to close the gap 37 between the die 17 and the work lifter 51 divided into three parts, and the work W is placed on the work lifter 51. The ram 7 is lowered by appropriately operating the hydraulic device 9, and the work W is bent by the cooperation of the punch 15, the die 17 and the work lifter 51.

At this time, since the gaps 37 between the dies 17 are in close contact with each other, no indentation is produced and the work can be bent accurately.

Next, as described above, after the work W is subjected to the first-stage bending, the ram 7 is raised to a predetermined position. The specified position is such that when the ram 7 is raised, the work W and the work lifter 51
However, the work W is eventually at a position where the load is eliminated. This position means the above specified position. At this time, the work W is lightly held between the punch 15 and the work lifter 51, but has the same bending angle as that when the work W is taken out due to the spring back of the work W.

Next, the piston rod 35 of the slide cylinder 33 is contracted to move the movable die 17 into three parts.
Then, the work lifter 51 is moved in the left-right direction to form a gap 37 that is continuous with the gap 39, and the work bending angle measuring device 3 faces the gap 37 from below, and then the piston rod 25 of the ascending cylinder 27 projects. In short, the short and long arm X-links 65, 65L attached to the base bracket 29 and the work opening amount detecting means 31, 31
L is also rising. At this time, short and long X links 65, 6
5L is depressed by the biasing force of the center springs 89, 89L, and the side springs 91, 9
With the urging forces of 1L, 93, and 93L, the contact members 75 and 75L at the rear (left side in FIG. 1) first come into contact with the rear edge of the lower portion of the work W because the contact members 75 and 75L are slightly inclined forward. Then, the front contactors 75 and 75L also come into contact with the lower front side of the workpiece W while changing from the slightly inclined state to the upright state. Further, when the base bracket 29 rises to the specified position, the short and long arm X-links 65 and 65L spread against the urging force of the center springs 89 and 89L, and as shown in FIG. ) Is ready for measurement.

At this time, the second short and long links 73, 73L
The sliders 77 and 77L mounted on the lower end of the positive terminal 8 are located at appropriate positions of the potentiometers 81 and 81L, that is, at positions corresponding to the bending angle of the work W.
The potential between 7, 87L and the minus terminals 85, 85L is also a potential corresponding to the bending angle of the work W. That is, the short and long X links 65 and 65L and the contacts 75 and 7
The opening amount of the work W measured by 5L is converted into an electric quantity.

The angle signal converted into the electric quantity is supplied to the control unit 5
7 is transmitted. Since the angle signal that has entered the control device 57 is an analog value, the angle signal is converted into a digital signal by the A / D conversion device 59 and then the average value is calculated by the arithmetic device 61 in order to facilitate later control. Calculated
More accurate bending angle measurements are obtained. In this embodiment, the average value is obtained by converting the angle signal into two points (short and long arms X) in the width direction (front-back direction) of the work W as shown in FIG. As shown in FIG. 4, the work opening amount detecting means 2 extends in the longitudinal direction (left-right direction) of the work W as shown in FIG.
Since 1 is provided in two places, a total of four angle signals come in, so that the average value of these is output. The digital angle signal, which has become more accurate as an average value, is compared with a desired bending angle by the control unit 63 from the relational expression between the electric quantity and the bending angle to calculate a correction amount. The ram plunge amount is commanded. Then, the hydraulic device 9 lowers the ram 7 again by the feed-back amount fed back, and presses the work W again by the cooperation of the punch 15, the die 17 and the work lifter 51, so that the work W is set to a desired bending angle. Bending is performed so as to compensate, and bending is performed accurately.

As described above, according to this embodiment, the work bending angle measuring device 3 is provided with the X having the contacts 75 and 75L.
Since the link type detector 31 is used, the contactors 75 and 75L directly contact the two sides of the work W, so that there is an effect that accurate angle measurement can be performed.

Furthermore, since a plurality of workpiece bending angle measuring devices 3 can be provided at appropriate positions in the longitudinal direction of the workpiece W, if these measured values are averaged, the workpiece W
There is an effect that the influence of the undulation in the longitudinal direction can be averaged and more accurate angle measurement can be performed.

Further, since the work opening amount detecting means 21 can measure the angle at a plurality of places by the short and long arm links 65 and 65L in the width direction of the work W, if these measured values are averaged, the work can be measured. By averaging the effect of large elastic return near the bending R of W, there is an effect that more accurate angle measurement can be performed.

Further, in measuring the bending angle, it is not necessary to take out the work W from the press brake 1, and no step by the operator is included. , The work W can be accurately bent by being incorporated into an automatic cycle, which is effective in improving work efficiency.

It should be noted that the present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes.

[0036]

As will be understood from the above description of the embodiments, in the present invention, the die as the lower die in the press brake is divided into a plurality of dies, and an appropriate number of dies are moved in the left-right direction. It is provided freely so that a gap can be formed between each die. Then, in order to measure the bending angle of the work that is bent in the gap formed by moving the movable die in the left-right direction, the work bending angle measurement that can freely reach the lower side of the work from the gap. A device is provided.

Therefore, according to the present invention, it is possible to bend a workpiece while holding a plurality of divided dies in close contact with each other, and to reduce the precision without forming an indentation or the like at a joint portion of the dies. It is possible to perform good bending. After the work is bent, the work is held between the punch and the die with springback occurring, and the movable die is moved to create a gap between the dies. The bending angle of the work can be measured from below with the bending angle measuring device facing the gap, and the bending angle of the work can be accurately measured. Therefore, it is easy to perform another bending process to correct the bending angle, and the workpiece can be bent accurately.

[Brief description of the drawings]

FIG. 1 is an explanatory left side view of an X-link type detector and a work opening amount detector according to the present invention.

FIG. 2 is an explanatory plan view of FIG. 1;

FIG. 3 is a partial left side sectional view showing a relationship between a punch and a die.

FIG. 4 is an explanatory front view partially in section showing a relationship between the entire press brake and a work bending angle measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Press brake 3 Work bending angle measuring device 7 Ram 15 Punch 17 Die 21 Work opening amount detecting means 31 Detector 61 Calculation device 65 Short arm X link 65L Long arm X link 71 Center pin W Work 75 Contact

Claims (2)

(57) [Claims] In a method of bending a work by a punch and a die as upper and lower dies in a press brake, the work is bent by the punch and the die and held in a state in which springback occurs. Thereafter, the die, which has been divided into a plurality of dies, is moved in the left-right direction to form a gap between the divided dies, and a bending angle measuring device is directed downward from the gap to the lower side of the work to bend the work. A method of bending a work, comprising measuring the angle from below, closing the gap, and then bending the work again by the punch and die to correct the bending angle. 2. A press brake comprising an upper table provided with a punch and a lower table provided with a plurality of dies which are divided into a plurality of dies in the left-right direction, wherein an appropriate number of dies are provided movably in the left-right direction and a gap is formed between the dies. The lower table is provided with a work bending angle measuring device which is provided so as to be able to face the lower side of the work from the gap in order to measure the bending angle of the work from below at a position corresponding to the gap. Press brake characterized by the following.