JPH06328138A - Bending machine - Google Patents

Abstract

PURPOSE:To improve the accuracy of a bending angle of a work by correcting an indentation of a punch or a die preset by a working information of a nominal plate thickness of a work, etc., in accordance with the actual plate thickness of the work. CONSTITUTION:The vertical movable position of a pin 15 is detected by a laser type displacement gage through a reflecting plate and a moving quantity H1 from the reference position of a pin 15 is inputted into a controller. After the punch 15 is separated from the die 12, the work 31 is mounted on the die 12. A moving quantity H from the reference position of the pin 15 is inputted into the controller and the actual plate thickness (t)= H2-H1 in the bending position of the work 31 is calculated by the controller in accordance with the moving quantity H1, H2. The indentation of the punch 13 preset from the working information of the norminal plate thickness of the work 31, etc., is corrected. The punch 13 is moved down by the corrected indentation to bend the work 31 into a specified bending angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending machine for bending a plate-shaped work by pressing the plate-shaped work with an upper die and a lower die.

[0002]

2. Description of the Related Art A press brake is generally known as a bending machine that bends a plate-shaped work by pressing a plate-shaped work with an upper die and a lower die. The bending angle of the work to be bent by this press brake is determined by the pushing amount of the upper die or the lower die, and this pushing amount is usually determined by the NC device based on the machining information such as the nominal plate thickness of the work. Is calculated. However, the actual plate thickness of the work is generally not always uniform, and as shown in FIG. FIG. 5 shows the results of measuring the plate thickness of the SPC material as a work (n = 20). The SPC material has a slightly thicker central portion in the rolling direction than the edge portion.

Therefore, various techniques for measuring the actual plate thickness of the upper die or the lower die based on the actual plate thickness of the workpiece to measure the actual plate thickness, particularly in-line, have been proposed as follows. There is.・ The plate at the end of the work is placed by a contact type thickness gauge installed near the backstop with the work abutting against the backstop for positioning the work to be bent by the press brake. Measure the thickness.・ For example, JP-A-62
As disclosed in Japanese Patent No. 248515, the plate thickness at the bending position of the work to be bent is measured by a contact type plate thickness measuring machine installed on the front side of the press brake. For example, as disclosed in Japanese Patent Laid-Open No. 2-30327, the plate thickness at the bending position of the work to be bent is estimated based on the amount of change in the load of the drive source of the press brake.

[0004]

However, in the case of measuring the plate thickness at the end portion of the work by the contact type plate thickness measuring device installed in the vicinity of the back stop, the labor for measuring the plate thickness can be saved, As shown in FIG. 5, the plate thickness at the edge portion of the work and the plate thickness at the bending position of the work may differ greatly, so that the accuracy of the bending angle of the work deteriorates.・ While measuring the plate thickness at the bending position of the work with a contact type plate thickness measuring machine installed on the front side of the press brake, it has the advantage that the plate thickness at the bending position of the work can be measured. At that time, a step of measuring the plate thickness of the work is required. -Estimating the plate thickness at the work bending position based on the amount of change in the load of the drive source of the press brake has the advantage that the plate thickness can be measured without the step of measuring the plate thickness. In order to accurately estimate the plate thickness of this work, it is necessary to slowly move the upper mold or the lower mold up and down, and it takes time to estimate the plate thickness. Some press brakes to which such a technique (plate thickness measuring method) is applied require, for example, about one minute to estimate the plate thickness of the work, and this plate thickness measuring method is rarely used. Is the actual situation.

The present invention has been made in view of the above problems, and it is possible to efficiently measure the plate thickness of a work at a bending position in-line and improve the accuracy of the work bending angle. It is an object of the present invention to provide a bending machine that can be used.

[0006]

A bending machine according to the present invention has an upper die, a lower die, and an upper end portion projecting into a V groove of the lower die and vertically movable with respect to the lower die. A bending machine for bending a work by clamping a plate-like work by the upper die and the lower die, the bending machine comprising: Drive amount setting means for setting the drive amount of the die or the lower die, (b) die driving means for moving the upper die or the lower die up and down, (c) die position for detecting the vertical movement position of the upper die or the lower die Detecting means, (d) The movable member is constantly urged upward, and the movable member is held at a reference position where the upper end of the movable member is located above the upper surface of the lower mold in an unloaded state. Movable member holding means, (e) the above Movable member position detecting means for detecting the vertical movement position of the member, (f) the upper die or the lower die detected by the die position detecting means in each state of placing and non-mounting the work on the lower die. Based on the vertical movement position of the movable member detected by the movable member position detection means when the vertical movement position of the mold is a predetermined position where the tip of the upper mold is located below the upper surface of the lower mold, Plate thickness calculation means for calculating the actual plate thickness of the work, and (g) the upper die set by the drive-in amount setting means based on the actual plate thickness of the work calculated by the plate thickness calculation means or It is characterized in that it comprises a drive-in amount correcting means for correcting the drive-in amount of the lower mold.

The movable member holding means supports the lower end of the movable member and can move up and down, a guide member for guiding the up and down movement of the support member, and a guide member disposed along the guide member. It is preferable that the movable member position detecting means includes a reflection coil that moves up and down in synchronization with the movable member, and a compression coil spring that constantly biases the support member upward. It is preferable to include a mirror disposed below the plate, and a laser displacement meter that projects a laser beam onto the mirror and receives a reflected laser beam from the reflecting plate through the mirror.

[0008]

According to the bending machine of the present invention, the vertical movement position of the upper die or the lower die is determined by the position of the upper die or the lower die when the plate-like work is placed or not placed on the lower die. The vertical movement position of the movable member at a predetermined position below the upper surface of the lower die is detected, and the actual plate thickness of the workpiece is calculated based on the vertical movement position of the movable member. Then, the advance amount of the upper die or the lower die set in advance based on the actual plate thickness of the workpiece thus obtained is corrected, and the upper die or the lower die is moved by an amount corresponding to the corrected inward amount. Moved up and down.

[0009]

EXAMPLES Next, specific examples of the bending machine according to the present invention will be described with reference to the drawings. A plate thickness measuring device applied to a press brake as a bending machine according to an embodiment of the present invention is shown in FIGS. 1 to 3. The press brake 11 lowers an upper die 13 from above with respect to a lower die 12 placed on a die base (not shown) so that the lower die 12 and the upper die 13 form a plate-like work (not shown). It is an overdrive type that bends the work by pinching.

A vertical hole 12a is formed in the lower die 12 at the deepest portion of the V groove formed in the upper portion of the lower die 12, and the vertical hole 12a is inserted into the peripheral surface of the vertical hole 12a. A ball bush 16 is provided for guiding the pin 15 supported by the support member 14 so as to be vertically movable. The reference numeral 15a in FIG.
It is a collar part to prevent it from protruding above.

The support member 14 is provided with a support portion 14a for supporting the lower end of the pin 15, and a movable portion 14b connected to the support portion 14a and formed at a position lower than the support portion 14a by a required amount. The movable portion 14b is provided with guide pins 19, via linear bushes 18 respectively provided on the supports 17, 17 fixed to the movable portion 14b.
It is possible to move up and down along 19. These guide pins 19 and 19 are erected on the base 20, and the upper end portions of these guide pins 19 and 19 are supported and fixed to the tip end of a stand 22 fixed on the base 20 by bolts 21 and 21. . A guide member 23a is fixed between the supports 17 and 17 in the lower portion of the movable portion 14b, and a guide post 23b is provided upright on the base 20 below the guide member 23a. A movable portion 14b, that is, a compression coil spring 24 that normally biases the support member 14 upward is externally fitted between the guide member 23a and the guide post 23b between the guide member 23a and the guide post 23b. Are arranged.

In this way, the pin 15 is held in the reference position where the upper end of the pin 15 is located above the upper surface of the lower die 12 in the unloaded state.

A reflecting plate 25 is fixed to the surface of the supporting portion 14a of the supporting member 14 opposite to the surface on which the pins 15 are supported.
The mirror 2 is placed on the base 20 below the reflection plate 25.
6 are provided. Then, the laser light projected from the laser displacement meter 27 arranged at a predetermined position on the base 20 is irradiated onto the reflection plate 25 via the mirror 26, and the reflected laser light is transmitted via the mirror 26 to the laser. Type displacement meter 27
By receiving the light, the laser displacement meter 27 detects the vertical movement position of the reflection plate 25, in other words, the pin 15.

The upper die 13 has an upper die 1 with respect to the lower die 12.
A drive device 28 for vertically moving 3 and a position detector 29 for detecting the vertical movement position of the upper die 13 are provided. The drive device 28 is driven based on an output signal output from the control device 30. It Then, detection signals from the laser displacement meter 27 and the position detector 29 are input to the control device 30 as information for driving the drive device 28.

Next, the operation of the press brake 11 will be described based on FIG. 4 with reference to FIGS. 1 to 3. First, the upper mold 13 is separated from the lower mold 12. At this time, the pin 15 is held at the reference position by the support member 14, the guide member 23a, the guide post 23b, the compression coil spring 24, etc. (FIG. 4A). Next, the upper mold 13 is moved downward to a predetermined position where the tip of the upper mold 13 is positioned below the upper surface of the lower mold 12 by, for example, about 1 mm. Here, the position of the tip of the upper die 13 is set lower than the upper surface of the lower die 12 by, for example, about 1 mm, because when the upper die 13 is moved down more than necessary, the upper die 13 is bent when the next work is bent. This is because the plate thickness decreases due to bending deformation when the work is moved down by the same distance, which causes an error in the plate thickness measurement. The position detector 29 detects that the upper die 13 has reached the predetermined position.
When this detection signal is input to the control device 30, the drive device 28 is stopped based on the output signal of the control device 30. The vertical movement position of the pin 15 at this time is the reflection plate 2
The displacement amount H _{1 of the} pin 15 from the reference position (FIG.
(B)) is input to the control device 30. Next, the upper mold 13
After being separated from the lower die 12 again, the work 31 is placed on the lower die 12 (FIG. 4C). Next, the upper die 13 is moved down to the predetermined position again, and the movement amount H ₂ (FIG. 4D) of the pin 15 from the reference position is input to the control device 30 in the same manner. In this way, the actual plate thickness t at the bending position of the work 31 is calculated by the controller 30 as t = H ₂ −H ₁ based on the moving amounts H ₁ and H ₂ input to the controller 30. Based on the actual plate thickness t of the work 31 obtained in this way, the preset drive-in amount of the upper die 13 is corrected from the machining information such as the nominal plate thickness of the work 31. Then, the work 31 is bent at a predetermined bending angle α by lowering the upper die 13 by the corrected amount of pushing (FIG. 4 (e)).

According to the press brake 11 of this embodiment,
As shown in FIGS. 4 (b) and 4 (d), the upper die 13 is placed in a state where the work 31 is not placed on the lower die 12 and when the work 31 is placed on the lower die 12, and the tip of the upper die 13 is lower. Type 1
The reference position of the pin 15 when the pin 15 is moved down to a predetermined position slightly lower than the upper surface of the pin 2 (the upper end of the pin 15 is the lower mold 1
2 above the upper surface of 2) the amount of movement H ₁ , H
_Since the actual plate thickness t of the work 31 is calculated based on ₂ , the work 3 is bent when the work 31 is bent.
It is not necessary to separately provide the step of measuring the plate thickness of No. 1, and the actual plate thickness of the work 31 can be measured efficiently and in a short time. Then, since the pushing amount of the upper die 13 is corrected based on the actual plate thickness of the work 31, the accuracy of the bending angle of the work 31 can be improved. Further, since the actual plate thickness of the work 31 is calculated using the pin 15 as an intermediary, even if the material of the work 31 is non-uniform, an error in the bending angle of the work due to the material can be suppressed. Furthermore, for example, when the lower die is changed to change the bending angle of the work, it is possible to measure the plate thickness of the work in the same manner only by using pins having different lengths.

Next, Table 1 shows the measurement results of the plate thickness of the work when the press brake 11 of this embodiment is used and when the micrometer is used.

[Table 1]

As can be seen from the measurement results in Table 1,
The difference between the measured value of the work thickness measured by the press brake 11 and the measured value of the work thickness measured by the micrometer is about 3/100 mm at the maximum. Considering that the bending angle of the work differs by about 1 ° when the plate thickness of the work differs by 0.1 mm when used, this press brake 11
It can be said that the measurement result of the plate thickness of the work by is sufficient.

In this embodiment, in order to make the frontage of the press brake as large as possible and to make the height of the die base as low as possible, a mirror is used to refract the laser light projected from the laser displacement meter. Although the reflection plate is irradiated, if the press brake has a sufficient space, the reflection plate may be directly irradiated with laser light without using such a mirror. Further, in order to detect the vertical movement position of the pin, an eddy current type displacement sensor or the like can be used in addition to the laser type displacement meter.

[0020]

According to the present invention configured as described above, the movable member when the upper die is moved down to a predetermined position in a state where the work is placed on the lower die and when the work is not placed on the lower die, respectively. The actual plate thickness of the work is calculated based on the movement amount from the reference position, and the upper die or lower die driving amount preset from the machining information such as the nominal plate thickness of the work is calculated as the actual work of the work. Since it is corrected based on the plate thickness, it is not necessary to measure the plate thickness of the work separately when bending the work, and the actual plate thickness at the bending position of the work can be measured efficiently and in a short time. In addition, the accuracy of the bending angle of the work can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a plate thickness measuring device applied to a press brake according to an embodiment of the present invention.

FIG. 2 is a view on arrow A in FIG.

FIG. 3 is a configuration diagram of a main part of a plate thickness measuring device applied to a press brake according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating the operation of the press brake according to the embodiment of the present invention.

FIG. 5 is a diagram showing variations in plate thickness of a work (SPC material).

[Explanation of symbols]

 11: Press brake 12: Lower mold 13: Upper mold 14: Support member 15: Pin 23a: Guide member 23b: Guide post 24: Compression coil spring 25: Reflector plate 26: Mirror 27: Laser displacement meter 28: Drive device 29 : Position detector 30: Control device 31: Work

Claims (3)

[Claims] 1. An upper mold, a lower mold, and a movable member whose upper end is projected into a V groove of the lower mold and is movable up and down with respect to the lower mold. A bending machine that bends a plate-like work by pinching the work by: and (a) a drive-in amount that sets the drive-in amount of the upper die or the lower die based on the processing information of the work. Setting means, (b) die driving means for moving the upper die or the lower die up and down, (c) die position detecting means for detecting the vertical movement position of the upper die or the lower die, (d) always moving the movable member upward. Movable member holding means for biasing the movable member to a reference position in which the upper end of the movable member is located above the upper surface of the lower mold in the unloaded state, and (e) the movable member. Moving member position detection to detect the vertical movement position of Knowing means, (f) the vertical movement position of the upper die or the lower die detected by the die position detecting means in the state of placing the work on the lower die and the state of not placing the work on the tip of the upper die. On the basis of the vertical movement position of the movable member detected by the movable member position detection means when the predetermined position is located below the upper surface of the lower mold,
Plate thickness calculation means for calculating the actual plate thickness of the work, and (g) the upper die set by the drive-in amount setting means based on the actual plate thickness of the work calculated by the plate thickness calculation means or A bending machine, comprising a driving amount correction means for correcting the driving amount of a lower die. 2. The movable member holding means supports a lower end of the movable member and is vertically movable, a guide member for guiding the vertical movement of the support member, and the guide member disposed along the guide member. The bending machine according to claim 1, further comprising: a compression coil spring that constantly biases the support member upward. 3. The movable member position detection means includes a reflecting plate which moves up and down in synchronization with the movable member, a mirror arranged below the reflecting plate, and a laser beam projected to the mirror. The bending machine according to claim 1 or 2, further comprising: a laser displacement meter that receives the reflected laser light from the reflector through a mirror.