JP2624557B2 - Angle measuring device for bending machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to an angle measuring device of a bending machine suitable for measuring a current bending angle of a workpiece being bent.

2. Description of the Related Art Conventionally, for example, when measuring a bending angle of a bent work, it is common to inspect the work by applying an angle measuring jig such as a squarer or a retractor having a predetermined angle to the work.

However, these methods have a problem that a personal error of a measurer is generated and measurement takes a lot of time. In addition, in the flow of factory automation, it has been impossible to automate the inspection process. Furthermore, in the bending machine, the bending is performed by the relative approach / separation operation of the upper die (punch) and the lower die (die).
Automatic bending, that is, the moving position of the mold cannot be automatically determined so that the final bending angle becomes the target bending angle.

Therefore, conventionally, for example, Japanese Patent Publication No. Sho 63-2687 (a plate bending angle detecting device for press brake) detects the minimum bending angle of the work by imaging the end face of the work being bent with a visual sensor, and We are trying to perform automatic bending.

However, the conventional method of detecting the bending angle of a work with a visual sensor, such as the above-mentioned Japanese Examined Patent Publication No. 63-2687, is a method that detects the bending angle at the work end surface by imaging the work end surface. However, there is a problem that the bending angle cannot be accurately detected, and even if automatic bending is performed by using the detected value, the bending cannot be performed with high accuracy, and the bending cannot be put to practical use.

That is, in the case of a plate-shaped work that is bent,
The end face is usually distorted at the stage of the material, has burrs, or has a tapered cross section, and it is difficult to detect a regular bending angle from the shape of the work end face.

In particular, when imaging the end face of the workpiece by the reflection type imaging method, when the end face of the workpiece is a tapered surface, the reflected light has unevenness, and the image obtained by the reflected light has an actual shape. Will be different. In addition, when a transmission-type imaging device is configured, a light projector for that purpose must be provided, and the device must be increased in size.

Further, in the angle detection at the end face of the work, the predetermined position of the visual sensor is limited in the direction of the end face of the work, so that there is a problem that the frame configuration of the bending machine is limited.

In addition, in the angle detection at the end face of the work, as shown in FIG. 15, the work is distorted in a bow shape when viewed from the front side of the bending machine due to a so-called sagging phenomenon. There was a problem that the angle was not a representative value.

(Problems to be Solved by the Invention) Therefore, the present inventors have recently set the intersection angle between two planes as a measurement surface of a work to be bent into a V-shape when viewed from the lateral direction of the bending machine. As the angle measurement method to be measured,
A plane is irradiated with one planar light by scanning with a slit light or a linear beam, and a linear light beam pattern appearing on each of the two planes is imaged in an imaging direction having a fixed relationship with the two planes and the plane irradiated with the planar light. Image on one plane coordinate from
An angle measurement method for measuring the intersection angle of the two planes from the angle made with respect to the reference line of the light ray pattern on the captured plane coordinates has been proposed.

According to this proposal, by irradiating one planar light to two planes as the surfaces to be measured and capturing an image of a light beam pattern appearing on each of the surfaces to be measured with the planar light by one imaging device,
The intersection angle of the two planes, that is, the bending angle of the workpiece can be measured from the relationship between the irradiation direction or posture of the planar light and the imaging direction.

However, even in the angle measuring method proposed as described above, in the bending machine, the work is interposed between the dies composed of the punch and the die, and the work is bent by the approaching / separating operation of the two dies. Therefore, there is a drawback that a mold exists at a position where an image is to be taken, and it is difficult to mount the mold on a bending machine.

Therefore, the present invention solves the above-mentioned problems of the prior art,
In addition, it is an object of the present invention to provide an angle measuring device of a bending machine which can improve the above proposal and can be mounted on a bending machine and can measure a bending angle of an inner portion from an end face of a work being bent with high accuracy. I do.

[Constitution of the Invention] (Means for Solving the Problems) The present invention has been made in view of the conventional problems as described above, and the invention according to claim 1 folds a plate-like work by a punch and a die. In the angle measuring device of a bending machine that performs bending, a left-right bending line direction of the work is defined as an X-axis direction, a front-rear direction orthogonal to the bending line is defined as a Y-axis direction, and the X-axis direction and the Y-axis direction. An irradiator that irradiates surface light before and after a bending line of the workpiece from a direction appropriately inclined with respect to the X-axis direction, when a vertical direction perpendicular to the axial direction is defined as a Z-axis direction. Provided on the punch or die, a visual sensor for imaging the light beam pattern of the planar light applied to the front and rear surfaces of the work,
Image processing that is provided on the punch or die in close proximity to the irradiator and calculates an angle formed by the front and rear surfaces with respect to the Z-axis direction based on a light beam pattern of the front and rear surfaces imaged by the visual sensor. A device is provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the image processing device processes the angle sample video signal,
It has a correction means for correcting the measurement angle.

(Example) Hereinafter, an example of the present invention will be described.

First, an outline of a bending machine for implementing the present invention will be described. As shown in a front view in FIG. 2, a bending machine (bender) is used.
1 includes a lower frame 3 and an upper frame 4 that have a side frame 2 that is C-shaped when viewed from the side, and that couples the side frame 2 on a lower side and an upper side.

A die 6 extending in the left-right direction via a die holder 5 is fixedly arranged on the upper part of the lower frame 3.

A vertically movable ram 7 is provided along the upper frame 4, and a punch 8 facing the die 5 is connected directly below the ram 7.

The upper end of the ram 7 is provided with cylinder devices SyL, SyR at both upper ends thereof via spherical bearings.
By the simultaneous operation of yR, the punch 8 is moved toward and away from the die 6.

The operation of the punch 8, ie, the cylinders SyL, SyR
Is operated by detecting a linear scale provided inside the side frame 2 with a rotary encoder provided on the side of the ram 7 and managing the position of the ram 7. The operating axis of the ram 7 is called a depth (D) axis, and the position of the ram 7 is controlled by an electrohydraulic servo circuit (not shown).

As an example of the position control method, the punch 8 is lowered at high speed until the tip of the punch 8 approaches the work placed on the die 6 using a speed pattern created in advance. Until it approaches the corner, it is operated at low speed, then switched to slow speed operation, paused at the final bending position determined in consideration of spring back of the work,
It is a system that rises thereafter.

An arm 9 that is rotatable in a horizontal plane is provided on the left side of the upper frame 4, and a pendant 10 as an operation panel is hung below the tip of the arm 9.

On the operation surface of the pendant 10, a display and various operation switches are provided. Although not shown, for example, an NC operation panel having a built-in NC device is provided on the left side of the figure.

On the other hand, in the bending machine 1 of the present example, an imaging device 11 for angle measurement is provided at the center of the punch 8 and is connected to an image processing device 12 placed on the ground via a power line 13 and a signal line 14. Have been.

An angle display 15 and appropriate operation keys are arranged on the board of the image processing device 12. The image processing device 12 is connected to an NC device in the NC operation panel.

The details of the imaging device 11 are shown in FIG. (A) is a front sectional view, and (b) is a central right side sectional view of (a).

As illustrated, the imaging device 11 includes a laser diode 16 as an irradiator that irradiates slit light SL as planar light toward an upper surface of a work to be bent into a hole 15 provided in the punch 8, The lens 17 captures a linear light beam pattern appearing before and after the bending line on the upper surface of the work with these planar lights.
And a visual sensor 19 having a CCD area sensor 18. A protection filter 20 for dust prevention is provided on a surface of the hole 15 facing the workpiece.

FIG. 3 shows a model of the optical arrangement of the imaging device 11.

In the drawing, first, the visual sensor 19 is arranged on a vertical axis along the punch 8, and captures an image of a light beam pattern appearing on the work W directly below the visual sensor.

The vertical axis is Z, the bending line direction is X, and the front-rear direction of the bending machine 1 is Y axis.

In this state, the slit light SL moves the YZ plane at an angle β.
Only in the plane inclined in the X-axis direction.

FIG. 4 is an explanatory diagram of an optical system showing the relationship of FIG. 3 on three-dimensional coordinates XYZ.

In the context of FIG. 4, 2 plane W _F for the front and rear of the workpiece W, the crossing angle of W _B alpha, i.e. the bending angle of the workpiece W, Z
It can be expressed as the sum of the inclination angles α _F and α _B of the planes W _F and W _B with respect to the axis.

α = α _F + α _B (1) Accordingly, by measuring the inclination angles α _F and α _B and obtaining the sum thereof, the intersection angle α between the two planes can be obtained.

FIG. 5A is a plan view of FIG. 4, and FIG.
FIG. 5 (c) is a right side view of FIG.

In the figure, the plan view of FIG. 5A can be imaged on the area sensor 18 of the visual sensor 19 of the imaging device 11.

Therefore, in the plan view of FIG. 5 (a), a planar light each object surface W _F inclination angle beta with respect to the imaging direction Z of each beta _F with respect to W _B, beta _{B (in} this example beta _F = β _B ), the angles between the X-axis of the light beam patterns P _F and P _B appearing on the front and rear planes are θ _F and θ _B , respectively, and the height of each plane in the front view is H _F ,
H _B, each ray pattern P _F, the projected length of the X axis P _B L _F, When L _B, the following equation holds to the plane W _F.

Accordingly, the inclination angle alpha _F of the plane W _F is calculated by _{tanα F = tanθ F · tanβ F} α F = tan -1 (tanθ F · tanβ F) ...... (5).

Similarly, on the plane W _B , α _B = tan ⁻¹ (tan θ _B · tan β _F ) (6)

Therefore, the bending angle α of the work can be obtained by the equation (1).

If β _F = β _B = 45 degrees, then α = θ _F + θ _B , so there is no need to perform the calculations of equations (5) and (6). However, in order to reduce the size of the device, β = 15-30 ° or smaller.

In the above embodiment, the planar light is constituted by the slit light SL, but the planar light can also be obtained by scanning a linear beam on the irradiation surface. In addition, by forming the planar light with a spot or slit light in one plane, and by making the linear light pattern continuous with the spot light appearing on the line,
You can also get.

Further, in the above-described embodiment, a CCD camera is used as the visual sensor 19, but any other device that can capture a two-dimensional image may be used. Also, as a light emitter,
Although the laser diode 16 that irradiates the slit light SL is taken as an example, any laser diode that can irradiate planar light may be used. However, since the linearity of the planar light affects the angle detection accuracy, a light emitter having high linearity such as a laser beam can detect with higher accuracy.

FIG. 6 shows an image processing device connected to the visual sensor 19.
12 is a block diagram of the internal configuration of FIG.

The image processing device 12 of the present example includes a CPU 2
1. ROM 22, RAM 23, input / output device (I / O) 24, display interface 25, and image memory 26 are connected. This image memory 26 converts the video signal of the visual sensor 19 into a binary signal. A binarizing (A / D) circuit 27 is connected.

The display 15 is connected to the display interface 25. An NC device 28 provided in the NC operation panel is connected to the input / output device 24.

In the above configuration, the visual sensor 19 is stored in the image memory 26.
The CPU 21 executes the processing shown in FIG. 7 to determine the angles α _F and α _B , and calculates the bending angle α of the work W by the sum thereof, and displays the image on the display 15 or the NC. Device 28
The calculation result is output to.

In FIG. 7, in step 701, the angle β (β _F , β _B )
Is determined, and if not, the angle β is set in step 702.

Next, in step 703, image data is input. In step 704, the inclination angles θ _F , θ _B on the memory are detected from the light beam patterns P _F , P _B.
The process returns to step 703 through step 703. If the detection is successful, the process proceeds to step 706 to calculate the work bending angle α from the equations (1) to (6), and outputs it in step 707.

The NC device 28 that has input the measured bending angle α can perform automatic bending by a control method similar to the control method shown in, for example, Japanese Patent Publication No. 63-2687.

That is, the NC device 28 inputs the current bending angle α, and controls the position of the punch 8 so that the angle α becomes the target angle α ₀ .
It is possible to control the bending angle after springback so as to have the product accuracy.

However, the bending angle α measured in this example is not obtained from the end face shape of the work W, and the work W
Since the two planes W _F of the front and rear, a W _B is obtained by imaging the inside of the work surface from the end face as a measurement surface, which can deal with measurement angle as workpiece bending angle,
From a practical point of view, an effect different from that of the conventional example can be obtained.

FIG. 8 shows that holes 15 _F and 15 _B are provided before and after the bending line of the crack 8, and lenses 17 _F and 17 _B and a CCD are provided in each of the holes 15 _F and 15 _B.
This is an example in which visual sensors 19 _F and 19 _B provided with area sensors 18 _F and 18 _B are provided, and protective filters 20 _F and 20 _B are provided below the holes to form an imaging device 29. Diodes provided for each of the visual sensors 19 _F and 19 _B are not shown. The diode may be common to both the visual sensors 19 _F and 19 _B.

Also in this example, the bending angle α of the work W can be obtained based on the principle shown in FIGS.

FIG. 9 is an example in which an imaging device is provided on the die 6 side.
(A) is a front sectional view, and (b) is a right side central sectional view thereof.

In this example, as shown in FIGS. 1A and 1B, a laser diode 16, a lens 17,
This is an example in which the imaging device 30 is provided with the CCD area sensor 18.

In this example, from the relationship shown in FIG. 10, the measurement surface before and after the bending line BL can be detected from the bottom side of the work W, and the bending angle α of the work W can be obtained.

FIG. 11 shows an example in which the imaging device 31 is constituted by a pair of visual sensors 19 _F and 19 _B provided before and after the bending line on the die 6 side, similarly to the embodiment shown in FIG.

Also in this example, the bending angle α can be obtained by the same principle as that of FIG. However, since the imaging direction of each visual sensor can be arbitrarily designed, the inclination re-obtained by both visual sensors α _F , α
The composite value of _B must be offset by an amount corresponding to the shift between the two imaging directions.

FIG. 12 shows an imaging unit in which two relatively short through-holes 32 and 33 are provided in the left-right direction of the punch 8, and the through-holes 32 and 33 image the respective surfaces to be measured before and after the bending line of the work W. 34,3
5 is provided, and the work W
This is an example in which the bending angle α is determined.

In this example, the through-holes 32 and 33 are provided in the various punches 8 and the imaging units 34 and 35 are mounted in these through-holes, so that the angle α of the work W can be measured. There is no need to incorporate an imaging device into the mold, and equipment costs can be reduced. It is also possible to use one through-hole 32, 33 and measure the angle with one imaging unit. The hole may be a notch provided on the side of the mold instead of a through hole.

FIG. 13 shows that the die 6 is provided with through holes 36 and 37,
This is an example in which imaging units 38 and 39 for imaging respective surfaces to be measured before and after a bending line of a work W via a work 37 are built in a die holder 40.

In this example, the die 6 need only be provided with through holes 36 and 37 having a relatively small diameter, so that equipment costs can be reduced and various bending operations can be performed. Also in this example, the through hole is 1
The hole may be a book, and the hole may be formed by a notch instead of a through hole.

FIG. 14 shows an image pickup unit 41 used in FIG. 12 and FIG.
It is a perspective explanatory view which shows the example of a structure of (34,35,38,39).

As shown, the imaging unit 41 includes a box-shaped case 42.
In addition, a lens 17, a CCD camera 18, and a laser diode 16 for irradiating the slit light SL are incorporated so as to form the relationship shown in FIG. In order to make the apparatus compact, it is preferable to make β = about 10 to 20 °.

As described above, if the imaging unit 41 of this example is used, it can be applied to various molds by incorporating it in a mold or a mold holder or by attaching it to a part thereof.

Here, the mounting accuracy of the imaging unit 41 to the mold or the holder poses a problem, but the mounting accuracy may be relatively low.

The reason is that the image processing apparatus shown in FIG.
This is because the measurement error can be easily corrected by arranging the angle sample work in the actual bent state and measuring the angle.

In the above-described embodiment, an example in which the bending angle of one work is measured has been described. However, a plurality of sets of imaging devices are provided along the longitudinal direction of the work, and the angle is measured at a plurality of positions, whereby the measurement according to the work length is performed. Or by calculating the average value,
An appropriate bending angle α can be obtained.

The sagging phenomenon of the work can be measured by measuring the work bending angles at a plurality of positions, and the intermediate plate and shim adjustment amount can be optimized. When a central cylinder is provided, the adjustment amount can be optimized.

The present invention is not limited to the above embodiment, but can be implemented in an appropriate mode by making appropriate design changes.

[Effects of the Invention] As can be understood from the above description of the embodiment, the invention according to claim 1 performs bending of a plate-shaped work (W) by a punch (8) and a die (6). In the angle measuring device of the bending machine, the bending direction of the workpiece (W) in the left-right direction is defined as the X-axis direction, the front-rear direction perpendicular to the bending line is defined as the Y-axis direction, and the X-axis direction and the Y-axis direction. when the vertical direction perpendicular to the axial direction is a Z axis direction, the workpiece (W) of the bend line around the surface (W _F, W _B) of the relative, inclined appropriately with respect to the X-axis direction An irradiator (16) for irradiating planar light from a direction is provided on the punch (8) or the die (6), and the surfaces (W _F , W _B ) irradiated on the front and rear surfaces of the work (W) are illuminated. Ray pattern (P _F ,
P _B ) a visual sensor (19) for imaging the irradiator (16)
Closely provided on the punch (8) or die (6), said front and rear faces captured by the visual sensor (19) (W _F, W
Light pattern (P _F of _B), based on P _B), formed by providing the front and rear surfaces with respect to the Z-axis direction (W _F, the image processing apparatus for computing an angle W _B) (2) Things.

As apparent from the above configuration, in the invention according to claim 1, before and after surface W _F of the bending line in the plate-shaped workpiece W by the irradiator 16 provided on the punch 8 or the die 6, the W _B planar irradiating light is for imaging the light pattern P _F, P _B of the irradiator 16 the plane W _F before and after the by visual sensor 19 provided in close proximity to, W _B to be irradiated a planar light. And
Based on the light beam patterns P _F , P _B of the front and rear surfaces W _F , W _B imaged by the visual sensor 19, the front and rear surfaces W _F ,
The inclination angle of W _B is a configuration that calculates the image processing apparatus 12.

That is, according to the present invention, irradiation 16 is punch 8 that irradiates planar light before and after the surface W _F of the bending line of the workpiece W, with respect to W _B
Alternatively, since it is provided on the die 6, it is possible to irradiate the planar light near the bending line of the work W, and the contour of the light pattern of the planar light becomes clear by being close to the work W. In this case, the imaging of the light beam pattern can be accurately performed.

And the surface before and after the bending line of the work W with respect to the Z axis
W _F, since the angle of W _B is intended to be operational, even if the front and rear surface W _F with respect to the Z-axis, the angle of W _B different, is possible to determine the bending angle of the workpiece W accurately You can do it.

According to the second aspect of the present invention, since the image processing apparatus is provided with the correcting means 13 for processing the angle sample video signal and correcting the measurement angle, the measurement error can be easily corrected.

[Brief description of the drawings]

1 (a) and 1 (b) are a front sectional view and a right side central sectional view showing a mounting structure of an imaging device to a punch according to an embodiment of the present invention, and FIG. 2 is provided with an angle measuring device. FIG. 3 is a perspective explanatory view showing a modeled version of FIG. 1, FIG. 3 is an explanatory view showing the optical relationship of the embodiment shown in FIG. 3 in a coordinate system, and FIG. a), (b), and (c) are a plan view, a front view, and a right side view of FIG. 4, FIG. 6 is a block diagram of an image processing apparatus, FIG. 7 is a flowchart showing an algorithm of angle measurement, FIG. FIG. 9 is a side sectional view showing another mounting structure of the image pickup apparatus. FIGS. 9 (a) and 9 (b) are front sectional views showing the mounting structure of the image pickup apparatus to the die and a right side central sectional view thereof. Is a perspective explanatory view showing a model of the embodiment of FIG. 9, FIG. 11 is a right side sectional view showing another mounting structure of the imaging device, and FIG. a) and (b) are right side sectional views showing an example of adaptation of the imaging unit to the punch, FIG. 13 is a right side sectional view showing an example of adaptation of the imaging unit to the die, and FIG. 14 is a configuration example of the imaging unit FIG. 15 is a perspective view of a workpiece having a sagging phenomenon. 6 ...... die 8 ...... punch 11 ...... imaging device 12 ...... image processing apparatus 16 ...... laser diode 19 ...... visual sensor 28 ...... NC device 41 ...... imaging unit W ...... workpiece W _F ...... front of the work W _B … Back surface of the workpiece _PF , P _B … Ray pattern SL… Slit light α _F , α _B … Inclination angle β (β _F , β _B )… Slit light irradiation angle

Claims (2)

(57) [Claims] An angle measuring device for a bending machine for bending a plate-shaped work (W) by a punch (8) and a die (6). When the X-axis direction is set, the front-rear direction orthogonal to the bending line is set to the Y-axis direction, and the perpendicular direction orthogonal to the X-axis direction and the Y-axis direction is set to the Z-axis direction, the bending of the work (W) is performed. front and rear surfaces of the line (W _F, W _B) with respect to the X
An irradiator (16) for irradiating planar light from a direction appropriately inclined with respect to the axial direction is provided on the punch (8) or the die (6), and the front and rear surfaces (W _F , A visual sensor (19) for imaging the light beam pattern (P _F , P _B ) of the planar light applied to the WB (W _B ) is provided in close proximity to the irradiator (16) to the punch (8) or the die (6). ), And based on the light beam pattern (P _F , P _B ) of the front and rear surfaces (W _F , W _B ) imaged by the visual sensor (19), the front and rear surfaces ( An angle measuring device for a folding machine, comprising an image processing device (12) for calculating an angle formed by W _F , W _B ). 2. An image processing apparatus according to claim 1, wherein said image processing device includes a correction means for processing a video signal of an angle sample and correcting a measurement angle. Angle measuring device for bending machine.