JP6595163B2 - Press brake and multistage bending method - Google Patents

Description

  The present invention relates to a press brake and a multistage bending method.

  In order to bend a metal plate material, a bending machine called a press brake is used (see Patent Documents 1 and 2).

  The press brake includes an upper table to which a die holder for attaching a punch die is attached and a lower table to which a die holder for attaching a die die is attached. When bending a plate material, an operator attaches a punch die and a die die to each die holder. The press brake lowers the upper table to the lower table and bends the plate material between the punch die and the die die.

  One of the processing methods for bending a plate material using a press brake is multi-stage bending. Multi-step bending is a processing method of processing a plate material into a curved surface by bending a flat plate material at an obtuse angle at a plurality of locations to form a plurality of planar regions.

JP 2006-205256 A Japanese Patent No. 2680460

  It is difficult to accurately process a plate material into a desired bent shape by multi-stage bending. If the plate material is sequentially bent at a plurality of locations in order to produce a product having a desired bending shape, the angle error generated at each location accumulates, resulting in a considerably large angle error as a whole. As a result, the manufactured product has a bent shape different from the desired bent shape.

  Therefore, in order to manufacture a product having a desired bending shape, a press brake and a multistage bending method capable of accurately processing a plate material into the desired bending shape are required.

  In order to meet such a demand, an object of the present invention is to provide a press brake and a multistage bending method that can accurately process a plate material into a desired bending shape.

The present invention provides an upper table for holding a punch die, a lower table for holding a die die, a movable slide table on one of the upper table and the lower table, and a fixed table on the other. A movement mechanism for moving the slide table in a direction approaching the fixed table, and an operation of moving the plate material forward by a predetermined distance after bending the plate material by a predetermined target bending angle at one bending position, When the plate material is bent into a curved shape by a plurality of plane regions by bending the plate material at a plurality of bending positions at a predetermined interval, respectively, the plate material is bent at the plurality of bending positions. In each of the bending steps, the sliding mechanism is moved by the moving mechanism while the plate material is sandwiched between the punch die and the die die. First and second angle sensors disposed respectively on the front and rear of, the die tool for measuring the angle of the plate upon bending the sheet by moving the table, the in each step, A target for calculating a target angle of the plate material to be measured by the first and second angle sensors, which is necessary to set an angle formed by adjacent planar regions across each bending position as the predetermined target bending angle. A target for calculating a target stroke for each step, which is an amount for pushing the plate material from a position where the punch mold comes into contact with the plate material, which is necessary for bending the plate material by the respective target angles. A stroke calculation unit, a slide control unit for controlling the slide table to move based on the target stroke for each step, and a slide control unit. When the slide table is moved to complete the bending process of at least one step, an actual bending angle based on the target bending angle in the at least one step and the angle of the plate material measured by the first and second angle sensors is determined. There is provided a press brake including an angle correction unit that calculates an error from a bending angle and corrects a target bending angle in one or more steps after the at least one step so as to eliminate the error.

  In the press brake described above, the angle correction unit divides the error between the target bending angle and the actual bending angle in one process by the number of all processes after the one process, and a value obtained by dividing the error. It is preferable to correct the target bending angle of each of the subsequent steps so as to be resolved in all the subsequent steps.

  In the press brake described above, when the angle correction unit completes the bending process in a plurality of processes, the error between the target bending angle in the last process and the actual bending angle in the plurality of processes is determined after the plurality of processes. It is preferable to correct the target bending angle of the next one step so as to be solved in one step.

  In the press brake, each time the angle correction unit completes the bending process in one step, the error between the target bending angle and the actual bending angle in the one step is calculated as the next one in the one step. It is preferable to correct the target bending angle of the next one step so as to be solved in one step.

According to the present invention, the plate material is bent at each of a plurality of bending positions on the basis of the finished angle, the finished radius on the inner surface side, and the number of bendings of the product manufactured by bending the plate material into a curved surface in a plurality of plane regions. A predetermined target bending angle to be bent in the process and a predetermined interval between adjacent bending positions are determined, and the punch mold is relatively moved from the state in which the plate material is sandwiched between the punch mold and the die mold. By repeating the operation of moving the plate material to the front side by a distance corresponding to the predetermined interval after moving the plate material in the bending direction by the predetermined target bending angle at one bending position, in each step of bending the plate material in the plurality of bending positions, the second angle sensor arranged on the rear side of the die mold a first angle sensor arranged on the front side of the die mold Te, the angle of the plate when bending the plate material is measured, the at each step, the required angle between the plane regions adjacent across each bend position to the predetermined target bending angle, Calculate the target angle of the plate material to be measured by the first and second angle sensors, and from the position where the punch mold is in contact with the plate material, which is necessary to bend the plate material by the target angle. is an amount of pushing the plate material, wherein the target stroke calculated for each step, for each of the steps, prior SL based on the target stroke, by moving the punch tool in the direction of relative the die tool bending the plate, and when complete the bending of at least one step, the angle of the plate material target bend angle and the first and second angular sensors is measured in at least one step Obtains an error between the actual bending angle brute, so as to eliminate the error, said to provide a multi-stage bending method for correcting the target bend angle in one or more steps after the at least one step.

  In the above-described multi-stage bending method, the error between the target bending angle and the actual bending angle in one step is divided by the number of all steps after the one step, and the value obtained as a result of the division is then It is preferable to correct the target bending angle of each of the subsequent steps so as to be eliminated in all steps.

  In the above-described multistage bending method, when the bending process in a plurality of steps is completed, an error between the target bending angle in the last step and the actual bending angle in the plurality of steps is determined as one step next to the plurality of steps. It is preferable to correct the target bending angle of the next one step so as to eliminate the above.

  In the above-described multi-stage bending method, every time the bending process in one step is completed, the error between the target bending angle and the actual bending angle in the one step is eliminated in one step after the one step. It is preferable to correct the target bending angle of the next one step.

  According to the press brake and the multistage bending method of the present invention, it is possible to accurately process a plate material into a desired bending shape.

It is a whole block diagram which shows the press brake of 1st and 2nd embodiment. FIG. 2 is a partial configuration of a press brake according to the first embodiment, and is a block diagram illustrating a specific functional internal configuration example of a slide control unit 21 in FIG. 1. It is a block diagram which shows the schematic structural example of a laser type angle sensor. In a press brake provided with a laser type angle sensor, it is a schematic side view showing the state before processing. It is a figure which shows the captured image which the imaging part of a laser type angle sensor images in the state of FIG. It is a schematic side view which shows the process of the process 1 by a press brake provided with a laser type angle sensor. It is a figure which shows the captured image which the imaging part of a laser type angle sensor images in the state of FIG. It is a schematic side view which shows the process of the process 2 by a press brake provided with a laser type angle sensor. It is a figure which shows the captured image which the imaging part of a laser type angle sensor images in the state of FIG. It is a schematic side view which shows the process of the process 3 by a press brake provided with a laser type angle sensor. It is a figure which shows the captured image which the imaging part of a laser type angle sensor images in the state of FIG. It is a schematic side view which shows the process of the process 4 by a press brake provided with a laser type angle sensor. It is a figure which shows the captured image which the imaging part of a laser type angle sensor images in the state of FIG. It is a schematic side view which shows the process of the process 5 by a press brake provided with a laser type angle sensor. It is a figure for demonstrating an example of the method of determining whether a predetermined bending position enters in the imaging region of a laser type angle sensor. It is a figure which shows the captured image which the imaging part of a laser type angle sensor images in the state of FIG. It is a figure which shows the target angle in each process when the frequency | count of bending is 30 times. It is a figure for demonstrating an example of the method of selecting a line segment and calculating | requiring an angle, when the line image contained in the captured image imaged with the laser type angle sensor is a broken line which consists of several line segments. In a press brake provided with a contact-type angle sensor, it is a schematic side view which shows the state before a process. It is a figure for demonstrating the specific structure of a contact-type angle sensor. It is a schematic side view which shows the process of the process 1 by a press brake provided with a contact-type angle sensor. It is a schematic side view which shows the state of pinching before the process start of the process 2 by the press brake provided with a contact-type angle sensor, and the state of completion | finish of a process. It is a schematic side view which shows the state of pinching before the process start of the process 3 by the press brake provided with a contact-type angle sensor, and the state of completion | finish of a process. It is a figure which shows the case where an angle cannot be measured correctly with a contact-type angle sensor. It is the elements on larger scale of FIG. It is a flowchart which shows the operation | movement of the multistage bending process by the press brake of 1st Embodiment, and the procedure by the multistage bending process method of 1st Embodiment. It is a partial structure of the press brake of 2nd Embodiment, and is a block diagram which shows the functional specific internal structural example of the slide control part 21 in FIG. It is a figure which shows the 1st example of the correction method with which the angle correction part with which the press brake of 2nd Embodiment is provided correct | amends a target bending angle.

  Hereinafter, the press brake and the multistage bending method according to the first and second embodiments will be described with reference to the accompanying drawings.

<Overall Configuration of Press Brake of First and Second Embodiments>
The overall configuration of the press brake is common to the first and second embodiments. The press brake shown in FIG. 1 schematically includes a press brake control device 20, an upper table 30 that is a movable slide table, and a lower table 40 that is a fixed table. The press brake control device 20 can be configured by an NC device.

  Although not shown in FIG. 1, the press brake is used to position a rear end portion (end portion on the back side of the paper) of the plate material W and a back gauge 52 for moving the back gauge 52 (see FIG. 2). A back gauge drive unit 51 (see FIG. 2).

  The press brake control device 20 is connected to an input device 10 and a storage unit 15 that stores a processing condition database to be described later.

  The upper table 30 is moved up and down by main cylinders 35L and 35R provided on the left and right. The position of the upper table 30 is controlled so as to approach the lower table 40 and away from the lower table 40. The main cylinders 35L and 35R are moving mechanisms that move the upper table 30.

  In the lower table 40, crowning in the direction of the upper table 30 is controlled by crowning cylinders 45L and 45R provided on the left and right. Description of the crowning control operation by the crowning cylinders 45L and 45R is omitted.

  In FIG. 1, the number of main cylinders and the number of crowning cylinders is two, but the present invention is not limited to this.

  An upper mold holder (not shown) is attached to the upper table 30, and a lower mold holder (not shown) is attached to the lower table 40. A punch die 31 is attached to the upper die holder, and a die die 41 is attached to the lower die holder.

  The punch mold 31 and the die mold 41 may be held by the upper table 30 and the lower table 40 directly or indirectly, respectively. The plate material W to be bent is sandwiched between the punch die 31 and the die die 41 and bent.

  The press brake control device 20 generally includes a slide control unit 21, D / A converters 22L and 22R, counter input units 23L and 23R, and an A / D converter 24. The slide control unit 21 includes a target stroke calculation unit 214. The D / A converters 22L and 22R may be provided outside the press brake control device 20.

  The target stroke calculation unit 214 uses the bending conditions input by the input device 10 and the processing condition database stored in the storage unit 15 to start from the position (pinching position) where the punch die 31 contacts the plate material W. A target stroke which is a target stroke for pushing the punch die 31 is calculated. Since the method for obtaining the target stroke is known, the description thereof is omitted here.

  When the operator instructs the start of processing of the plate material W, the press brake control device 20 responds to the processing start instruction to lower the upper table 30 and push the punch die 31 into the plate material W by the target stroke. The cylinders 35L and 35R are controlled.

  The slide control unit 21 generates control data composed of digital values for controlling the position when the upper table 30 is lowered or raised. The D / A converters 22L and 22R convert the control data into control values made up of analog values. The control value is input to the amplifiers 32L and 32R.

  The amplifiers 32L and 32R amplify the control value and supply it to the motors 33L and 33R. The motors 33L and 33R cause the bidirectional rotary pumps 34L and 34R to rotate forward or backward.

  The main cylinders 35L and 35R can be lowered by rotating the bidirectional rotary pumps 34L and 34R in the normal direction. The main cylinders 35L and 35R can be raised by reversing the bidirectional rotary pumps 34L and 34R.

  The slide control unit 21 generates control data such that the stroke when the punch die 31 is brought into contact with the plate material W and the plate material W is processed becomes a preset target stroke, and the D / A converters 22L and 22R are generated. To supply.

  The control values output from the D / A converters 22L and 22R are input to the amplifiers 32L and 32R, and the control values amplified by the amplifiers 32L and 32R are supplied to the motors 33L and 33R. Therefore, the motors 33L and 33R rotate the bidirectional rotary pumps 34L and 34R in the normal direction to lower the upper table 30 and lower the main cylinders 35L and 35R so as to push the punch die 31 into the plate material W by the target stroke. Can do.

  The position detectors 38L and 38R detect the vertical position of the upper table 30. The position detectors 38L and 38R can detect the position of the upper table 30 as a counter value. The position detectors 38L and 38R supply position detection values (count values) to the counter input units 23L and 23R. Thereby, the press brake control device 20 can know the position of the upper table 30 in the vertical direction.

A pair of laser-type angle sensors or contact-type angle sensors for measuring the angle of the plate material W are arranged on both the front side (front side) and the back side (rear side) of the die mold 41. In FIG. 1, a laser type angle sensor 61 or a contact type angle sensor 71 located on the front side is shown. The rear laser type angle sensor 62 or the contact type angle sensor 72 is shown in FIG.

  The angle detection signals detected by the laser type angle sensors 61 and 62 or the contact type angle sensors 71 and 72 are input to the press brake control device 20. As will be described later, the laser type angle sensors 61 and 62 or the contact type angle sensors 71 and 72 detect the angle of the plate material W with reference to a surface obtained by extending the upper end surface of the die mold 41.

<Press Brake and Multistage Bending Method of First Embodiment>
As shown in FIG. 2, the slide control unit 21 includes a bending angle / pitch calculation unit 211, a back gauge position calculation unit 212, a target angle calculation unit 213, and a target stroke calculation unit 214 as functional internal configurations. , An adder 215, a subtracter 216 , an angle detector 217, and a stroke correction value calculator 218.

  If the finishing angle of the product to be formed by multistage bending, the finishing radius (finishing R) on the inner surface side, and the number of times of bending the plate material W to make the product are determined, the plate material W can be bent once. The bending angle and the pitch that is the interval between the bending positions are determined. The bending angle is an angle formed by adjacent planar regions on the inner surface side of the product. The bending angle will be referred to as α. The bending angle α and the pitch are constant values or variable values.

  If the bending angle α and the pitch are constant values, arc-shaped multistage bending can be performed. If the bending angle α and the pitch are variable values that change sequentially, elliptical arc-shaped multistage bending can be performed. Therefore, the bending angle α and the pitch when the plate material W is bent into a curved surface by a plurality of plane regions are set to predetermined values, respectively.

  If the finished angle is 90 degrees and the number of times of bending is 30, the bending angle α is 3 degrees. That is, if the plate material W is bent by 3 degrees at each of the 30 positions, a product with a finished angle of 90 degrees is produced.

  When the operator inputs the product finishing angle, the product finishing R value, and the bending number value by the input device 10 shown in FIG. 1, these values are input to the bending angle / pitch calculation unit 211. The bending angle / pitch calculation unit 211 calculates the bending angle α and the pitch. The bending angle α is input to the target angle calculation unit 213, and the pitch is input to the back gauge position calculation unit 212.

  In order to perform the multistage bending of the plate material W, it is necessary to shift the position of the plate material W forward in each bending process. Therefore, the back gauge 52 may be moved to the front side for each bending process.

  The back gauge position calculation unit 212 calculates a back gauge position for each bending process based on the input pitch. Based on the back gauge position for each bending process calculated by the back gauge position calculation unit 212, the back gauge driving unit 51 drives the back gauge 52 to move forward for each bending process.

  The target angle calculation unit 213 calculates a target angle for each bending process (target angle for each process) based on the input bending angle α. As will be described later, the target angle may be an angle formed by adjacent planar regions (sides) of the product, or may be an angle formed by non-adjacent planar regions (sides).

  The target angle is determined based on the angle on the front side and the back side of the punch die 31 of the plate material W measured by the laser type angle sensors 61 and 62 or the contact type angle sensors 71 and 72. It may be. Further, the target angle may be an angle determined based on an angle on the front side and the rear side of the punch die 31 of the plate material W with reference to a surface obtained by extending the upper end surface of the die die 41.

  The target angle for each process calculated by the target angle calculation unit 213 is input to the target stroke calculation unit 214. The storage unit 15 stores the material conditions of the plate material W, the mold conditions of the punch mold 31 and the die mold 41, and the bending conditions as a processing condition database. Material conditions, mold conditions, and bending conditions are collectively referred to as processing conditions. The machining conditions read from the storage unit 15 are input to the target stroke calculation unit 214.

  The material conditions are the tensile strength, Young's modulus, plate thickness, and the like of the plate material W. The die conditions are the die height and die angle of the punch die 31 and the die die 41, the punch tip radius of the punch die 31, the die shoulder radius of the die die 41, and the like. Bending conditions are bending length, bending speed, and the like.

  The target stroke calculation unit 214 calculates a target stroke for pushing the punch die 31 from the pinching position where the punch die 31 contacts the plate material W based on the target angle for each process and the processing conditions.

  As an example, when the finishing angle is 90 degrees and the number of times of bending is 30 times (that is, the bending angle α is 3 degrees), the slide control unit 21 exemplifies the target angle and the target in each step as shown below. Stroke and back gauge position can be calculated automatically. Here, the case where the angle on the inner surface side of the product is set as the target angle using the laser type angle sensors 61 and 62 is shown.

Process Target angle (°) Target stroke (mm) Back gauge position (mm)
1 177 1.000 160.00
2 174 1.050 158.00
3 171 1.100 156.00
4 168 1.150 154.00
::::
30 168 1.150 100.00

  The reason why the target angle is as described above will be described in detail later. The above target stroke and back gauge position are merely examples, and are values corresponding to processing conditions.

Target stroke outputted from the target stroke calculator 214 is input to the adder 215.

The angle detector 217 detects the angle of the plate material W based on the angle detection signal output from the laser type angle sensors 61 and 62 or the contact type angle sensors 71 and 72. Based on the target angle and the angle detected by the angle detection unit 217, the stroke correction value calculation unit 218 sets the target when the angle of the plate material W when the punch die 31 is lowered by the target stroke does not become the target angle. A stroke correction value for correcting the stroke is calculated.

Stroke correction value is smaller as the plate material W approaches the target angle, becomes 0 when the plate material W becomes the target angle.

Adder 215, the target stroke and the stroke correction value to the summing. Stroke of adder 215 outputted the summing result than is input to the subtractor 216.

The position detection values detected by the position detectors 38L and 38R are input to the subtracter 216 from the counter input units 23L and 23R .

  Therefore, the position detection value input to the subtracter 216 indicates a stroke in which the punch die 31 is lowered in the direction of the die die 41 beyond the origin. The stroke input to the counter input units 23L and 23R is a value that decreases as the lowering amount of the punch die 31 approaches the target stroke, and becomes 0 when the stroke matches the target stroke.

After the position detectors 38L and 38R detect that the upper table 30 (punch die 31) is lowered by the target stroke amount, the angle detector 217 measures the angle, and if the target angle is not reached, the stroke correction value is again obtained. Is calculated, the target stroke is corrected, and the operation of lowering the upper table 30 is repeated.

Position detector 38L, 38R is, after detecting that the upper table 30 (punch 31) is lowered by the target stroke, the angle detection section 217, the plate material W when it detects that a target angle, the stroke The output of the correction value calculation unit 218 is zero. Accordingly, the lowering of the upper table 30 is stopped. When the slide control unit 21 raises the upper table 30, the bending process by one bending process is completed.

(Description of each bending process when the laser type angle sensors 61 and 62 are used)
Hereinafter, the operation of the press brake and the multistage bending method when the laser type angle sensors 61 and 62 are used will be specifically described.

  As shown in FIG. 3, the laser angle sensors 61 and 62 include a laser light emitting unit 631 that emits laser light and an imaging unit 632.

  FIG. 4 shows a state before processing in step 1, which is the first bending step when the number of bendings is 30. As shown in FIG. 4, the laser type angle sensor 61 is disposed on the front side of the die mold 41, and the laser light emitting unit 631 irradiates the lower surface of the plate material W protruding on the front side of the die mold 41 with laser light. . The lower surface of the plate material W is an outer surface of a product formed by multi-stage bending the plate material W.

  The laser light emitting unit 631 of the laser type angle sensor 61 irradiates laser light in the width direction of the plate material W along the optical axis 611. The imaging unit 632 of the laser type angle sensor 61 images the lower surface of the plate material W using the angle range indicated by the broken line as the imaging region 612.

  The laser type angle sensor 62 is disposed on the rear side of the die mold 41, and the laser light emitting unit 631 irradiates the lower surface of the plate material W protruding on the rear side of the die mold 41 with laser light.

  The laser light emitting unit 631 of the laser type angle sensor 62 irradiates laser light in the width direction of the plate material W along the optical axis 621. The imaging unit 632 of the laser type angle sensor 62 images the lower surface of the plate material W with the angle range indicated by the broken line as the imaging region 622.

  In the state of FIG. 4, images captured by the imaging units 632 of the laser type angle sensors 61 and 62 are captured images 61i and 62i shown in FIGS. As shown in FIGS. 5A and 5B, the line images 61iL and 62iL captured by the captured images 61i and 62i are in a straight line. The angles θL1 and θL2 of the line images 61iL and 62iL with respect to the bottom surfaces of the captured images 61i and 62i are 90 degrees.

  If the picked-up images 61i and 62i are in the states shown in FIGS. 5A and 5B, the front and rear portions of the plate material W from the punch die 31 are the upper end surfaces of the die die 41, respectively. It is located on the extended surface and the angle detected by the laser type angle sensors 61 and 62 is zero.

  2 is based on the angles θL1 and θL2 of the line images 61iL and 62iL included in the captured images 61i and 62i output from the laser type angle sensors 61 and 62, and the front portion and the rear portion of the plate material W. It can be detected that the angle on the inner surface side formed by the side portion is 180 degrees.

  FIG. 6 shows a step 1 of bending the sheet material W by an angle α (here, 3 degrees) in the first bending step. The punch die 31 bends the plate material W at the bending position P1. In Step 1, the target angle θ on the inner surface side formed by the plane area on the front side and the plane area on the back side from the bending position P1 is 180−α (that is, 177 degrees).

  As shown in FIG. 6, in a two-dimensional state when the plate material W is viewed from the side surface side, the plane area in front of the bending position P1 is represented as side S1, and the plane area in the rear side is represented as side S2. Hereinafter, similarly, each process will be described using sides.

  In FIG. 6, angles β1 and β2 formed by the upper end surface of the die mold 41 and the sides S1 and S2 are α / 2, respectively. If the sum of the angles β1 and β2 is α (that is, 3 degrees), the plate material W can be set as the target angle θ in the step 1.

  At the end of processing in step 1, images captured by the imaging units 632 of the laser type angle sensors 61 and 62 are captured images 61i and 62i shown in FIGS. 7A and 7B, respectively. As shown in FIGS. 7A and 7B, the line images 61iL and 62iL captured by the captured images 61i and 62i are straight lines, and the angles θL1 and θL2 of the line images 61iL and 62iL are (90− 1.5) degrees.

  If the captured images 61i and 62i are in the states shown in FIGS. 7A and 7B, the angles β1 and β2 are α / 2, respectively. The angle detection unit 217 can detect the angles of the sides S1 and S2 based on the angles θL1 and θL2 of the line images 61iL and 62iL included in the captured images 61i and 62i output from the laser type angle sensors 61 and 62. It is possible to detect that the target angle θ is 180−α.

  FIG. 8 shows a step 2 following the step 1 in which the plate material W is moved forward by one pitch and the punch die 31 bends the plate material W at the bending position P2 by an angle α. In step 2, the side between the bending positions P1 and P2 is the side S2, and the side behind the bending position P2 is the side S3.

  The interval between the bending positions P1, P2, that is, the side length Ls for one pitch is shorter than ½ of the width Dw of the die die 41. In this case, the laser type angle sensors 61 and 62 cannot measure the angle formed by the adjacent sides S2 and S3. In step 2, as can be seen from FIG. 8, the laser type angle sensors 61 and 62 can measure the angle formed by the side S1 and the side S3.

  In step 2, the target angle θ formed by the sides S1 and S3 is 180-2α (ie, 174 degrees). In FIG. 8, when the angles formed by the upper end surface of the die die 41 and the sides S1 and S3 are β1 and β3, if the sum of the angles β1 and β3 is the angle 2α, the plate material W is set to the target angle θ in the step 2. can do.

  At the end of processing in step 2, images captured by the imaging units 632 of the laser type angle sensors 61 and 62 are captured images 61i and 62i shown in FIGS. 9A and 9B, respectively. As shown in FIG. 9A, the line image 61iL captured by the captured image 61i is further inclined than the line image 61iL shown in FIG. As shown in FIG. 9B, the line image 62iL captured by the captured image 62i has the same inclination as the line image 62iL shown in FIG.

  The angle θL1 of the line image 61iL is (90−4.5) degrees, and the angle θL2 of the line image 62iL is (90−1.5) degrees.

  If the captured images 61i and 62i are in the states shown in FIGS. 9A and 9B, the sum of the angles β1 and β3 is the angle 2α. The angle detection unit 217 can detect the angles of the sides S1 and S3 based on the angles θL1 and θL2 of the line images 61iL and 62iL included in the captured images 61i and 62i output from the laser type angle sensors 61 and 62. It is possible to detect that the target angle θ is 180-2α.

  FIG. 10 shows a step 3 following the step 2, in which the plate material W is further moved forward by one pitch, and the punch die 31 bends the plate material W by the angle α at the bending position P3. In step 3, the side S3 is between the bending positions P2 and P3, and the side S4 is behind the bending position P3.

  Similarly in step 3, the laser angle sensors 61 and 62 cannot measure the angle formed by the adjacent sides S3 and S4. The same applies to step 4 and subsequent steps. In step 3, as can be seen from FIG. 10, the laser type angle sensors 61 and 62 can measure the angle formed by the side S1 and the side S4.

  In step 3, the target angle θ formed by the side S1 and the side S4 is 180-3α (that is, 171 degrees). In FIG. 10, if the angles formed by the upper end surface of the die mold 41 and the sides S1 and S4 are β1 and β4, and the sum of the angles β1 and β4 is the angle 3α, the plate material W is set to the target angle θ in the step 3. can do.

  At the end of processing in step 3, images captured by the imaging units 632 of the laser type angle sensors 61 and 62 are captured images 61i and 62i shown in FIGS. 11A and 11B, respectively. As illustrated in FIG. 11A, the line image 61iL captured by the captured image 61i is further inclined than the line image 61iL illustrated in FIG. As illustrated in FIG. 11B, the line image 62iL captured by the captured image 62i has the same inclination as the line image 62iL illustrated in FIG.

  The angle θL1 of the line image 61iL is (90−7.5) degrees, and the angle θL2 of the line image 62iL is (90−1.5) degrees.

  If the captured images 61i and 62i are in the states shown in FIGS. 11A and 11B, the sum of the angles β1 and β4 is the angle 3α. The angle detection unit 217 can detect the angles of the sides S1 and S4 based on the angles θL1 and θL2 of the line images 61iL and 62iL included in the captured images 61i and 62i output from the laser type angle sensors 61 and 62. It is possible to detect that the target angle θ is 180-3α.

  FIG. 12 shows a step 4 following the step 3 in which the plate material W is further moved forward by one pitch and the punch die 31 bends the plate material W three times at the bending position P4. In step 4, the space between the bending positions P3 and P4 is the side S4, and the back side from the bending position P4 is the side S5.

  In step 4, as can be seen from FIG. 12, the laser type angle sensors 61 and 62 can measure the angle formed by the side S1 and the side S5.

  In step 4, the target angle θ formed by the sides S1 and S5 is 180-4α (ie, 168 degrees). In FIG. 12, if the angles formed by the upper end surface of the die mold 41 and the sides S1 and S5 are β1 and β5, and the sum of the angles β1 and β5 is the angle 4α, the plate material W is set to the target angle θ in the step 4. can do.

  At the end of the processing in step 4, images captured by the imaging units 632 of the laser type angle sensors 61 and 62 are captured images 61i and 62i shown in FIGS. As shown to (a) of FIG. 13, the line image 61iL imaged by the captured image 61i becomes a broken line which consists of the line segment 61iL1 and the line segment 61iL2.

  As illustrated in FIG. 13B, the line image 62iL captured by the captured image 62i is a straight line and has the same inclination as the line image 62iL illustrated in FIG.

  In the line image 61iL shown in FIG. 13A, the angle detector 217 may measure the angle of the line segment 61iL2. The angle θL1 of the line image 61iL (line segment 61iL2) is (90-10.5) degrees, and the angle θL2 of the line image 62iL is (90-1.5) degrees.

If the captured images 61i and 62i are in the states shown in FIGS. 13A and 13B, the sum of the angles β1 and β5 is the angle 4α. The angle detection unit 217 can detect the angles of the sides S1 and S5 based on the angles θL1 and θL2 of the line images 61iL and 62iL included in the captured images 61i and 62i output from the laser type angle sensors 61 and 62. It is possible to detect that the target angle θ is 180-4α.

  FIG. 14 shows Step 5 following Step 4 in which the plate material W is further moved forward by one pitch, and the punch die 31 bends the plate material W by an angle α at the bending position P5. In step 5, the space between the bending positions P4 and P5 is the side S5, and the back side from the bending position P5 is the side S6.

  As can be seen from FIG. 14, in step 5, since the bending position P2 enters the imaging region 612 of the laser type angle sensor 61, the laser type angle sensors 61 and 62 measure the angle formed by the side S2 and the side S6. Can do.

  If the angle formed by the side S1 and the side S6 is the target angle θ, the target angle θ is 180-5α. However, in Step 5, the angle formed by the side S2 and the side S6 is the target angle θ. 180-4α (ie, 168 degrees).

  Whether or not the bending position P2 falls within the imaging region 612 of the laser type angle sensor 61 can be determined by geometric calculation for determining whether or not the bending position P2 is located above the lower visual line 612f. The lower visual line 612f can be obtained by an equation using the position of the laser type angle sensor 61 and the optical constant of the lens used in the imaging unit 632.

  As shown in FIG. 15, an XY coordinate system is assumed with the X axis passing through the lower surface of the die die 41 and the Y axis passing through the centers of the punch die 31 and the die die 41. The lower visual line 612f is set to Y = aX + b. The elevation angle of the imaging unit 632 of the laser type angle sensor 61 is φ, and the field angle is ψ. The center of the lens (not shown) of the imaging unit 632 is assumed to be (Xc, Yc). The position of the bending position P2 is (Xn, Yn).

At this time,
a = tan (φ−ψ / 2) (1)
b = Yc−aXc (2)
It becomes.

The bending position P2 is located above the lower visual line 612f when the condition shown in the following expression (3) is satisfied.
Yn> a (Xn / 2) + b (3)

  In this example, it is determined whether or not the bending position P2 is positioned above the lower visual line 612f. However, the position of an arbitrary bending position is (Xn, Yn) and can be determined by Expression (3). it can.

  Returning to FIG. 14, assuming that the angles formed by the upper end surface of the die die 41 and the sides S2 and S6 are β2 and β6, if the sum of the angles β2 and β6 is the angle 4α, the plate material W is changed to the target angle θ in the step 5. It can be.

  In the state of FIG. 14, the images captured by the imaging units 632 of the laser type angle sensors 61 and 62 are the captured images 61i and 62i shown in (a) and (b) of FIG. As shown in FIG. 16A, the line image 61iL picked up by the picked-up image 61i is a polygonal line composed of line segments 61iL1, 61iL2, 61iL3.

  As shown in FIG. 16B, the line image 62iL captured by the captured image 62i is a straight line and has the same inclination as the line image 62iL shown in FIG.

  In the line image 61iL shown in FIG. 16A, the angle detector 217 may measure the angle of the line segment 61iL2. The angle θL1 of the line image 61iL (line segment 61iL2) is (90-10.5) degrees, and the angle θL2 of the line image 62iL is (90-1.5) degrees.

If the captured images 61i and 62i are in the states shown in FIGS. 16A and 16B, the sum of the angles β2 and β6 is the angle 4α. The angle detection unit 217 can detect the angles of the sides S2 and S6 based on the angles θL1 and θL2 of the line images 61iL and 62iL included in the captured images 61i and 62i output from the laser type angle sensors 61 and 62. It is possible to detect that the target angle θ is 180-4α.

  The same operation is repeated in step n after step 6 after step 5. Here, n is 7-30. In step n, the bending position P (n-3) between the side (n-3) and the side (n-2) enters the imaging region 612 of the laser type angle sensor 61. Therefore, in the process n, the laser type angle sensors 61 and 62 may measure the angle formed by the side (n−3) and the side (n + 1). In step n, all target angles θ are 180-4α.

  The above steps 1 to 30 are summarized as shown in FIG. In FIG. 17, n is any one of 7 to 30. As shown in FIG. 17, the front measurement side sf is the side having the same number as the bending position with the highest number among the bending positions located above the lower visual line 612f. However, if there is no bending position located above the lower visual line 612f, the front measurement side is 1. The rear side measurement side sr is a side (n + 1) where n is 1 to 30 here.

Since the target angle θ is an angle formed by the front measurement side sf and the rear measurement side sr, the difference between the front measurement side sf and the rear measurement side sr is multiplied by the bending angle α in one bending step. Equation (4) is obtained.
θ = 180− (sr−sf) α (4)

  As shown in FIGS. 13A and 16A, when the line image 61iL included in the captured image 61i is a broken line composed of a plurality of line segments, the angle is determined by selecting the line segment. An example will be described. FIG. 18 is a line image 61iL shown in FIG.

  As described with reference to FIG. 16A, the angle detection unit 217 illustrated in FIG. 2 preferably obtains the angle θL1 formed by the longest line segment 61iL2 as the angle of the line image 61iL. Therefore, the angle detection unit 217 divides the line image 61iL into line segments 61iL1 to 61iL3 using, for example, a piecewise linear approximation method.

  As shown in FIG. 18, the angle detection unit 217 uses a straight line AB connecting the pixels A and B located at both ends of the line image 61iL, and obtains a straight line distance between the straight line AB and each pixel constituting the line image 61iL. . The angle detection unit 217 sets the pixel at the position where the straight line distance is maximum (the pixel having the absolute maximum length) as the pixel C.

  The angle detection unit 217 obtains a linear distance between the straight line AC connecting the pixel A and the pixel C and each pixel constituting the line image 61iL between the pixels A and C. The angle detection unit 217 sets a pixel (a pixel having an absolute maximum length) at a position where the linear distance is maximum as a pixel D. If there are more line segments, the same operation is repeated until the absolute maximum length of the line segment becomes sufficiently small.

  As described above, the angle detection unit 217 can obtain the points A to D in the line image 61iL shown in FIG. 18, and can recognize the line segments 61iL1 to 61iL3. The angle detection unit 217 selects a line segment 61iL2 longer than a predetermined length as a line segment for calculating an angle.

  The angle detection unit 217 obtains an equation representing a straight line passing through the line segment 61iL2 by, for example, the least square method. The angle detection unit 217 calculates the angle θL1 of the line image 61iL (line segment 61iL2) by obtaining the slope of the straight line.

  When the line image 61iL is a polygonal line composed of more line segments, the angle detection unit 217 may obtain the angle of the line image 61iL based on a predetermined line segment, not limited to the longest line segment. The angle detection unit 217 may obtain the angle of the line image 61iL based on the line segment set in advance by the processing program.

(Description of each bending process when the contact type angle sensors 71 and 72 are used)
Next, the operation of the press brake and the multistage bending method when the contact type angle sensors 71 and 72 are used will be specifically described.

  When the angle of the plate material W is not detected, the contact type angle sensors 71 and 72 are separated from the die mold 41 and are positioned below. When the angle of the plate material W is detected, the contact-type angle sensors 71 and 72 are moved upward by a predetermined moving mechanism and disposed at a position in contact with the die die 41 as shown in FIG.

  The contact-type angle sensors 71 and 72 have a main body portion 731 and a protruding portion 732 that can be moved into and out of the main body portion 731. As shown in FIG. 20, a slightly projecting tip 733 is provided at the upper end of the projecting portion 732.

  Before the start of processing shown in FIG. 19, the protruding portion 732 is in a state of not protruding most. When the plate material W is bent and displaced upward as shown in FIG. 20, the projecting portion 732 projects upward in accordance with the displacement of the plate material W upward. The contact-type angle sensors 71 and 72 can measure the angles of the front portion and the rear portion of the plate material W from the punch die 31 based on the protrusion amount of the protrusion 732 and the dimensions La and Lb. .

  In the state of FIG. 19, the contact type angle sensors 71 and 72 detect that the angle is 0 degree with reference to a surface obtained by extending the upper end surface of the die die 41. At this time, the angle on the inner surface side of the plate material W sandwiching the position of the punch die 31 is 180 degrees.

  FIG. 21 shows a step 1 of bending the plate material W by an angle α (here, 3 degrees) in the first bending step. The punch die 31 bends the plate material W at the bending position P1. In Step 1, the target angle θ on the inner surface side formed by the front side S1 and the rear side S2 from the bending position P1 is 180−α (that is, 177 degrees).

  In FIG. 21, the angles β1 and β2 formed by the upper end surface of the die mold 41 and the sides S1 and S2 are α / 2, respectively. If the sum of the angles β1 and β2 is α (that is, 3 degrees), the plate material W can be set as the target angle θ in the step 1.

  FIG. 22 shows a step 2 following the step 1 in which the plate material W is moved forward by one pitch, and the punch die 31 bends the plate material W at the bending position P2 by an angle α. FIG. 22A shows a pinching state before the punch die 31 comes into contact with the plate material W at the bending position P2 and the plate material W is bent. FIG. 22B shows a state in which the processing in step 2 in which the plate material W is bent at the bending position P2 is finished.

  In step 2, the side between the bending positions P1 and P2 is the side S2, and the side behind the bending position P2 is the side S3.

  As in the case of using the laser type angle sensors 61 and 62, the side length Ls for one pitch is shorter than ½ of the width Dw of the die mold 41, so that the contact type angle sensors 71 and 72 are adjacent to each other. The angle formed by S2 and side S3 cannot be measured. The same applies to step 3 and subsequent steps.

  Therefore, in step 2 and subsequent steps, the target angle is not the target angle θ on the inner surface side of the plate material W, but the angle of the side on the front side of the punch die 31 when the surface obtained by extending the upper end surface of the die die 41 is used as a reference. And the angle of the back side is the target angle. The target angle at this time is referred to as θβ.

  In the pinching state shown in FIG. 22A, the angle of the side S1 detected by the contact-type angle sensor 71 is β1p, and the angle of the side S3 detected by the contact-type angle sensor 72 is β3p.

  In the state where the processing shown in FIG. 22B is finished, the target angle θβ is an angle β1 of the side S1 measured by the contact-type angle sensor 71 and an angle β3 of the side S3 measured by the contact-type angle sensor 72. Total angle. The target angle θβ can be expressed by Equation (5).

  θβ = (β1 + β3) = α + (β1p + β3p) (5)

  FIG. 23 shows a step 3 following the step 2 in which the plate material W is moved forward by one pitch, and the punch die 31 bends the plate material W by the angle α at the bending position P3. FIG. 23A shows a pinching state. FIG. 23B shows a state in which the processing in step 3 is finished.

  In step 3, the side S3 is between the bending positions P2 and P3, and the side S4 is behind the bending position P3.

  In the pinching state shown in FIG. 23A, the angle of the side S1 measured by the contact-type angle sensor 71 is β1p, and the angle of the side S4 measured by the contact-type angle sensor 72 is β4p.

  In the state where the machining shown in FIG. 23B is finished, the target angle θβ is an angle β1 of the side S1 measured by the contact type angle sensor 71 and an angle β4 of the side S4 measured by the contact type angle sensor 72. Total angle. The target angle θβ can be expressed by Equation (6).

  θβ = (β1 + β4) = α + (β1p + β4p) (6)

  Similarly, after step 4, in the pinching state, the total angle obtained by adding the angle α to the total angle of the side angle measured by the contact-type angle sensor 71 and the side angle measured by the contact-type angle sensor 72. May be the target angle θβ at the end of machining.

  In the above description, the angle on the inner surface side of the sides S1 and S2 is the target angle θ only in FIG. 21, but the target angle θβ may be the target angle also in FIG. FIG. 19 shows a pinching state. The angle of the side measured by the contact-type angle sensor 71 and the angle of the side measured by the contact-type angle sensor 72 are 0, and the total angle is 0.

  In the transition from FIG. 19 to FIG. 21, since the total angle in the pinching state is 0, the total α (that is, 3 degrees) of the angles β1 and β2 becomes the target angle θβ.

  By the way, when the contact-type angle sensors 71 and 72 are used, as shown in FIGS. 24 and 25, a predetermined bending position (for example, the bending position P <b> 1) may be located in the vicinity of the distal end portion 733. In such a case, the relative position between the contact-type angle sensor 71 and the bending position may be shifted between pinching and machining, and the angle may not be measured accurately.

  Whether or not the case as shown in FIGS. 24 and 25 occurs can be calculated from the number of bendings and pitch of the multi-stage bending process, the die condition, and the like. Therefore, when it is found that the cases shown in FIGS. 24 and 25 occur, it is preferable to change the pitch so that the cases shown in FIGS. 24 and 25 do not occur.

  Further, when the operator inputs the product finishing angle, the product finishing R value, and the bending number value, and the bending angle / pitch calculation unit 211 calculates the bending angle α and the pitch, as shown in FIGS. It may be possible to set only a pitch other than the pitch at which the case occurs.

  Note that the target angle setting method in which the total angle of the front side angle and the rear side angle from the punch die 31 is set as the target angle θβ is limited to the case where the contact-type angle sensors 71 and 72 are used. In addition, even when the laser type angle sensors 61 and 62 are used, it can be adopted.

  The operation of the multistage bending process using the press brake according to the first embodiment and the procedure using the multistage bending process method according to the first embodiment will be described again using the flowchart shown in FIG.

  In FIG. 26, when the press brake starts to operate, and the user inputs the product finish angle, product finish R value, and bending number value by the input device 10, the slide control unit 21 sets these values in step S01. take in. In step S02, the slide control unit 21 calculates the bending angle α and the pitch.

  In step S03, the slide control unit 21 calculates a target angle θ (or θβ) for each process. In step S04, the slide control unit 21 calculates a target stroke for each process.

  In step S05, the press brake control device 20 determines whether an instruction to start machining has been issued. If no instruction to start machining is given (NO), the press brake control device 20 repeats the process of step S05.

If an instruction to start processing is given (YES), the slide control unit 21 lowers the upper table 30 in step S06 . In step S07, the slide controller 21 determines whether or not the target stroke has been reached. If the target stroke has not been reached (NO), the slide control unit 21 repeats the processes of steps S06 and S07.

If the target stroke is reached in step S07 (YES), the slide control unit 21 stops the slide of the upper table 30 in step S08. That is, the slide control unit 21 stops the pushing of the punch die 31 toward the die die 41. In step S09, the slide control unit 21 captures the angle of the plate W being processed measured by the laser type angle sensors 61 and 62 or the contact type angle sensors 71 and 72.

In step S10, the stroke correction value calculation unit 218 determines whether the target angle has been reached. If the target angle has not been reached (NO), the stroke correction value calculation unit 218 calculates a stroke correction value in step S11, and the slide control unit 21 repeats the processes in steps S06 to S11.

At step S10 when it reaches the target angle (YES), the slide control unit 21 receives an instruction to raise the upper table 30, in step S 12, raising the upper table 30. Slide control unit 21, at step S1 3, it determines whether the host vehicle has reached the final step. If not reached the final step (NO), the slide control unit 21, at step S1 4, to move the back gauge 52 and by one pitch to the front side.

Press brake controller 20, at step S1 5, determines whether or not an instruction of the processing of the next step is made. If an instruction processing is made (NO), the press brake control device 20 repeats the processing of Step S1 5.

If an instruction for processing is given in step S15 (YES), the slide control unit 21 returns the process to step S06, and repeats step S06 and subsequent steps in the same manner. Until it reaches the final step, the process of step S06～S 15 is repeated.

Upon reaching the final step, the slide control unit 21, at step S1 3, it is determined to have reached the final step (YES), the processing is terminated.

  As described above, according to the press brake and the multistage bending method of the first embodiment, the plate material W can be accurately processed into a desired bending shape.

<Press Brake and Multistage Bending Method of Second Embodiment>
The press brake and multistage bending method of the second embodiment will be described. The press brake and the multistage bending method of the second embodiment are preferable configurations that can improve the accuracy of a product that is multistage bent.

  If the bending angle at which the plate material W is actually processed deviates from the target bending angle, an error in the angle generated in each process may be accumulated. In this case, the shape (finished angle and finished radius) of the actually manufactured product is different from that of the product to be manufactured.

  Therefore, in order to improve the accuracy of the product, when the actual bending angle in one process deviates from the target bending angle and an error occurs, the error is processed in the subsequent process so that the deviation of the angle is eliminated. It is preferable to reflect the above.

  FIG. 27 shows the slide control unit 21 in the press brake of the second embodiment. In FIG. 27, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description of the same parts is omitted. The slide control unit 21 shown in FIG. 27 is an example of a configuration that reflects an error in processing in a later process.

  As shown in FIG. 27, the angle detected by the angle detector 217 is input to the target angle calculator 213. The target angle calculation unit 213 includes an angle correction unit 2131.

  FIG. 28 shows a first example of a correction method in which the angle correction unit 2131 corrects the target angle (bending angle). FIG. 28 uses the target angle setting method in which the total angle of the angle of the front side and the angle of the rear side of the punch die 31 is set as the target angle θβ described with reference to FIGS. Take the case as an example.

  Specifically, in FIG. 28, the finishing angle is 90 degrees, the number of bendings is 10 times, the calculation target bending angle α is 9 degrees, and the target bending angle α is corrected according to the actual bending angle αact. Shows the case.

  As shown in FIG. 28, in step 1, it is assumed that the actual bending angle αact is 8 degrees. Since the actual bending angle αact is 1 degree smaller than the target bending angle α in step 1, the angle correction unit 2131 corrects each target bending angle α so that the error of 1 degree is eliminated in the remaining steps 2 to 10. .

  Specifically, in step 2, the angle correction unit 2131 adds 0.11 degree to 9 degrees based on the calculation formula of 9− (αact of process 1−α of process 1) / 9. The target bending angle α of 2 is corrected to 9.11 degrees. The angle correction unit 2131 also adds 0.11 degrees to each target bending angle α in steps 3 to 10.

  In the process 2, when the machining is performed with the corrected target bending angle α (9.11 degrees), the actual bending angle αact does not become 9.11 degrees and an error may occur in the same manner. The angle correction unit 2131 corrects each target bending angle α so that the error generated in step 2 is eliminated in the remaining steps 3 to 10.

  Specifically, in step 3, the angle correction unit 2131 calculates the target bending in step 3 based on the calculation formula of 9 − (− 0.11) − (αact in step 2−α in step 2) / 8. The angle α is corrected. The calculation formula for obtaining the corrected target bending angle in steps 4 to 10 is as shown in FIG.

  The target bending angle α in Steps 2 to 10 shown in FIG. 28 is replaced with the target bending angle α corrected as described above.

  Here, the bending angle of each process when the plate material W is subjected to the multi-stage bending process is expressed using the symbol “Θ”.

The correction according to the first example is expressed by the following expression (7). In Equation (7), Θ _N is the target bending angle of the Nth step, Θ is the target bending angle corrected based on the actual bending angle of the Nth step, and the actual bending angle and the target bending angle of the Nth step. _Let Θ ' _{n be} the error and M be the number of bends.

  As described above, in the first example, the angle correction unit 2131 divides the error between the target bending angle in one process and the actual bending angle by the number of all processes after one process. The target bending angles of all the subsequent processes are corrected so that the resulting value is eliminated in all the subsequent processes.

  The correction method of the target bending angle in the angle correction unit 2131 is not limited to the first example. The angle correction unit 2131 may correct the target bending angle based on the second example shown in Expression (8). In Formula (8), P is a natural number of 2 or more.

  According to the second example, the angle correction unit 2131 performs the next process so as to eliminate the error between the target bending angle and the actual bending angle in the plurality of processes P in one process next to the plurality of processes P. Correct the target bending angle. In this case, the target bending angle is corrected for each (P + 1) step.

  When P is 3, an error between the target bending angle when the steps 1 to 3 are finished and the actual bending angle is corrected in the step 4, and the target bending angle and the actual bending angle when the steps 5 to 7 are finished. Is corrected in step 8. The same applies to step 9 and subsequent steps.

  As described above, in the second example, when the bending process of the plurality of processes is completed, the angle correction unit 2131 calculates an error between the target bending angle of the final process and the actual bending angle in the plurality of processes. The target bending angle of the next one process is corrected so as to be resolved in the next one process.

The angle correction unit 2131 may correct the target bending angle based on the third example shown in Expression (9). In the formula (9), and the error of the theta _'N between the actual bending angle and the target bending angle for N steps.

  According to the third example, the angle correction unit 2131 corrects the target bending angle of the next step so that the error between the target bending angle and the actual bending angle in the step of completing the machining is eliminated in the next step. . The error in step 1 is corrected in step 2, the error in step 2 is corrected in step 3, and the error in step 3 is corrected in step 4. The same applies to step 5 and subsequent steps.

  As described above, in the third example, the angle correction unit 2131 calculates the error between the target bending angle in one process and the actual bending angle every time the bending process in one process is completed. The target bending angle of the next one process is corrected so as to be eliminated in one process.

  The method of correcting the target bending angle by the angle correcting unit 2131 is not limited to the first to third examples. After the upper controller 30 is moved by the slide control unit 21 and the bending process of at least one process is completed, the angle correction unit 2131 is actually based on the target bending angle in the at least one process and the angle of the plate material W measured by the angle sensor. Find the error from the bending angle.

  The angle correction unit 2131 may correct the target bending angle in each process or selected process so that the error is eliminated in one or more processes after at least one process.

  When the angle correction unit 2131 corrects the target bending angle, it is possible to reduce or eliminate the deviation of the target angle θ (or θβ) in each process from the calculated value.

  According to the configuration in which the slide control unit 21 illustrated in FIG. 27 described above includes the angle correction unit 2131, a curved product can be manufactured with higher accuracy than the configuration illustrated in FIG. 2 that does not include the angle correction unit 2131. It becomes possible.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the present invention. In the present embodiment, the upper table 30 is a slide table and the lower table 40 is a fixed table, but the lower table 40 may be a slide table and the upper table 30 may be a fixed table.

  That is, when bending the plate material W, the punch die 31 may be relatively moved in the direction of the die die 41 from a state in which the plate material W is sandwiched between the punch die 31 and the die die 41.

21 Slide control unit 30 Upper table 31 Punch die 35L, 35R Main cylinder (moving mechanism)
40 Lower table 41 Die mold 61, 62 Laser angle sensor 71, 72 Contact angle sensor 213 Target angle calculation unit 214 Target stroke calculation unit 217 Angle detection unit 631 Laser light emission unit 632 Imaging unit
2131 Angle correction part W Plate material

Claims (8)

An upper table for holding the punch mold,
A lower table for holding the die mold,
One of the upper table and the lower table is a movable slide table, the other is a fixed table, and a moving mechanism that moves the slide table in a direction approaching the fixed table;
After the plate material is bent by a predetermined target bending angle at one bending position, the plate material is moved forward by a predetermined distance, and the plate material is repeatedly moved at the predetermined target bending at a plurality of bending positions at predetermined intervals. When the plate material is bent into a curved surface by a plurality of planar regions by bending only the angle, the plate material is bent at the plurality of bending positions, and the plate material is converted into the punch mold and the die metal. A first and a second arranged on the front side and the rear side of the die mold for measuring the angle of the plate material when the plate is bent by moving the slide table by the moving mechanism in a state sandwiched between molds, respectively. A second angle sensor;
In each of the steps, the plate material to be measured by the first and second angle sensors, which is necessary to set the angle formed by the adjacent planar regions across the bending positions as the predetermined target bending angle. A target angle calculator for calculating the target angle;
A target stroke calculation unit for calculating a target stroke for each step, which is an amount required to bend the plate material by the target angle, and is an amount to push the plate material from a position where the punch mold is in contact with the plate material;
A slide control unit for controlling the slide table to move based on the target stroke for each step;
When the slide control unit moves the slide table to complete the bending process of at least one step, the target bending angle in the at least one step and the angle of the plate material measured by the first and second angle sensors are set. An angle correction unit that calculates an error with an actual bending angle based on the target and corrects a target bending angle in one or more steps after the at least one step so as to eliminate the error;
Press brake with. The angle correction unit divides the error between the target bending angle and the actual bending angle in one process by the number of all processes after the one process, and the value obtained by dividing the error is calculated for all the subsequent processes. so as to eliminate the step, the press brake according to 請 Motomeko 1 correct all steps each target bending angle after the. When the bending process of the plurality of steps is completed, the angle correction unit eliminates the error between the target bending angle and the actual bending angle of the last step in the plurality of steps in one step following the plurality of steps. is thereby such, press brake according to 請 Motomeko 1 you correct the target bend angle of said next one step. Each time the angle correction unit completes the bending process in one step, the error between the target bending angle and the actual bending angle in the one step is canceled in one step following the one step. , press brake according to 請 Motomeko 1 you correct the target bend angle of said next one step. Predetermined to bend the plate material in a bending process at each of a plurality of bending positions based on the finished angle of the product to be manufactured by bending the plate material into a curved surface by a plurality of flat areas, the finished radius on the inner surface side, and the number of times of bending. Determining a target bending angle and a predetermined interval between adjacent bending positions,
From the state in which the plate material is sandwiched between the punch die and the die die, the punch die is relatively moved in the direction of the die die, and the plate material is moved at the predetermined target bending angle at one bending position. After bending, the plate material is disposed on the front side of the die mold in each step of bending the plate material at the plurality of bending positions by repeating the operation of moving the plate material to the front side by a distance corresponding to the predetermined interval. the first angle sensor and the second angle sensor arranged on the rear side of the die tool was to measure the angle of the plate when bending the plate,
In each of the steps, the plate material to be measured by the first and second angle sensors, which is necessary to set the angle formed by the adjacent planar regions across the bending positions as the predetermined target bending angle . Calculate the target angle,
Calculating a target stroke for each step , which is an amount required to bend the plate material by the target angle , and is an amount to push the plate material from a position where the punch mold is in contact with the plate material ;
For each of the steps, prior SL based on the target stroke, bend the plate material by moving the punch tool in the direction of relative the die tool,
When the bending process of at least one step is completed, an error between a target bending angle in the at least one step and an actual bending angle based on the angle of the plate material measured by the first and second angle sensors is obtained, A target bending angle in one or more processes after the at least one process is corrected so as to eliminate the error.
Multi-stage bending method. The error between the target bending angle and the actual bending angle in one process is divided by the number of all processes after the one process, and the value obtained by the division is eliminated in all the subsequent processes. multistage bending method according to 請 Motomeko 5 correct all steps each target bending angle after the. When the bending process of the plurality of steps is completed, the error between the target bending angle and the actual bending angle of the last step in the plurality of steps is eliminated in the next step after the plurality of steps. multistage bending method according to 請 Motomeko 5 correct the target bending angle for one step. Each time the bending process of one process is completed, the error between the target bending angle and the actual bending angle in the one process is canceled in the next one process after the one process. multistage bending method according to 請 Motomeko 5 correct the target bending angle steps.