JP2012179633A - Bending device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform a work of correcting a bending load so as to obtain a target bending angle.SOLUTION: A function expression that expresses relative displacement between a bending load to be applied on a work W and the bending angle of the work W is calculated based on bending conditions such as the material of the work W and on a target bending angle θ. A target bending load BF for making the bending angle of the work W a target bending angle θ is calculated based on the calculated function expression. When the bending angle formed by bending work performed with the calculated target bending load BF is deviated from the target bending angle θ, a correction function expression is calculated by correcting the function expression so that the load corresponding to a bending angle θ1, which is the angle deviated from the target bending angle θ of the calculated function expression, becomes the target bending load BF. Based on the correction function expression, the bending load corresponding to the target bending angle θ is calculated as a target bending load BF2 after correction, and bending is carried out with the calculated target bending load BF2.

Description

  The present invention relates to a bending apparatus that bends a plate-like workpiece at a target bending angle by a punch and a die.

  Conventionally, a corrected bending angle is calculated by comparing the current bending angle detected by the visual sensor with a target bending angle stored in advance in the NC device, and when the corrected bending angle is greater than or equal to an allowable value, the target bending angle is calculated. A bending apparatus that corrects a bending force (bending load) by outputting to an NC apparatus so as to approach an angle is known (see Patent Document 1 below).

Japanese Patent No. 2786473

  By the way, when bending a plate-shaped workpiece using a bending device such as a press brake, the processing conditions such as workpiece thickness, material, target bending angle, etc. are input to the NC device, giving it to the workpiece. The bending load to be calculated can be calculated.

  However, in this case, there are many cases where the target bending angle cannot be obtained due to variations in the thickness of the material itself, the longitudinal elastic modulus, and the like, and various processing conditions. Therefore, in practice, it is necessary to manually perform trial bending prior to regular bending to determine the correction amount of the bending load, and to input the correction amount to the NC device, which makes the work extremely complicated. ing.

  Therefore, an object of the present invention is to facilitate the operation of correcting the bending load so as to obtain a target bending angle.

  The present invention is a bending apparatus for bending a plate-shaped workpiece to a target bending angle by a punch and a die, and a bending load to be applied to the workpiece in accordance with bending conditions such as a workpiece material and the target bending angle. And a target bending load calculating means for calculating a target bending load for setting the bending angle of the workpiece as the target bending angle based on the data, and representing the relative displacement between the bending angle of the workpiece and the bending angle of the workpiece, When the bending angle of the workpiece after bending by the target bending load calculated by the target bending load calculating means deviates from the target bending angle, the load corresponding to the bending angle deviated from the target bending angle in the data is: Correcting means for correcting the data to be the target bending load, and after correcting the bending load corresponding to the target bending angle based on the data corrected by the correcting means And having a bending load correcting means for calculating a target bending load.

  According to the present invention, the initial bending load corresponding to the target bending angle is calculated as the corrected target bending load by correcting and calculating data representing the relative displacement between the bending load applied to the workpiece and the bending angle. Thus, the work of correcting the bending load so as to obtain a target bending angle can be facilitated.

It is a front view of the press brake which shows one Embodiment of this invention. It is a side view of the press brake of FIG. It is a control block diagram of the press brake of FIG. It is explanatory drawing which shows the state which is bending the workpiece | work with the punch and die | dye in the press brake of FIG. It is a flowchart which shows the processing operation by the control structure of FIG. (A) is a graph showing a load diagram calculated by inputting bending condition data, and (b) is a corrected load when the target bending angle is not obtained as a result of processing with the target load according to the load diagram of (a). (C) is the result of processing with the target load according to the load diagram of (a), the graph showing the diagram along with the load diagram of (a) as if the load diagram of (a) was translated upward It is a graph which shows the correction | amendment load diagram at the time of not becoming a target bending angle with the load diagram of (a) as what translated the load diagram of (a) rightward. (A) is a corrected load diagram when the target bending angle is not achieved as a result of processing with the target load according to the load diagram of FIG. 6 (a), and the load diagram of (a) is extended vertically. 6B is a graph shown together with the load diagram of FIG. 6A, and FIG. 6B is a corrected load diagram when the target bending angle is not obtained as a result of processing with the target load according to the load diagram of FIG. It is the graph which recalculates the load diagram of (a) by n 'and F', and shows with the load diagram of Fig.6 (a).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, a press brake 1 which is a bending apparatus according to an embodiment of the present invention has side plates on left and right side portions in FIG. 1 (both sides in a direction perpendicular to the paper surface in FIG. 2). 3, and a hydraulic cylinder 5 is attached to the upper part of the side plate 3. An upper table 9 having a punch P attached to the tip (lower end) is connected to the tip (lower end) of the piston rod 7 projecting downward from the hydraulic cylinder 5. That is, by operating the hydraulic cylinder 5, the upper table 9 as a ram can be moved up and down.

  Below the side plate 3, a lower table 11 having a die D mounted on the upper end is disposed, and a rear end 13 (not shown in FIG. 1) is disposed behind the lower table 11 (left side in FIG. 2). ing. A plate-shaped workpiece W is brought into contact with the abutment 13 before the machining is started, and positioning in the front-rear direction (left-right direction in FIG. 2) is performed.

  Further, a bar pedal 15 is extended in the left-right direction in FIG. 1 (in the direction orthogonal to the paper surface in FIG. 2) on the lower front surface of the lower table 11, and this bar pedal 15 is schematically viewed in plan view from above. The shaft 17 (FIG. 2) at both ends in the longitudinal direction is formed in a U-shape and is rotatably supported by a support plate 19 attached to the lower table 11.

  A mounting plate 21 is fixed to the front surface of the lower table 11 immediately below the bar pedal 15, and a spring 23 is interposed between the mounting plate 21 and the bar pedal 15. As a result, the bar pedal 15 is normally positioned upward due to the restoring force of the spring 23, but when it is stepped on by the operator, the bar pedal 15 is rotated and displaced downward against the restoring force of the spring 23. Then, when the operator depresses the bar pedal 15 described above, the hydraulic cylinder 5 is operated and the upper table 9 is lowered, and the workpiece W is bent by the cooperation of the punch P and the die D.

  Here, the above-described press brake 1 includes a load sensor 25 as a load detecting means shown in FIG. The load detected by the load sensor 25 corresponds to a bending load applied to the workpiece W by the punch P when the workpiece W is bent to a target bending angle. For example, the hydraulic pressure in the hydraulic cylinder 5 that operates during bending is detected. It consists of a hydraulic sensor.

  When bending the workpiece W, data of various bending conditions and a target bending angle θ (90 degrees here) are input from an input device 27 such as a keyboard shown in FIG. 3 (FIG. 5). Steps S1 and S2), and this input data is captured by the arithmetic unit 29 shown in FIG. Various bending conditions for the workpiece W include the material of the workpiece W (longitudinal elastic modulus E), the plate thickness t of the workpiece W, the tip angle PA of the punch P shown in FIG. PR, slope length PL of punch P, V width DV of die D, V angle DA of die D, and the like.

  The calculation device 29 takes in these bending condition data, and calculates a functional expression corresponding to a finished angle-load diagram (hereinafter simply referred to as a load diagram) A shown in FIG. 6A (step S3). ). That is, the arithmetic unit 29 calculates a functional expression representing a relative displacement between the bending load applied to the workpiece W and the bending angle (finished angle) of the workpiece W based on the bending conditions such as the material of the workpiece W and the target bending angle θ. A function formula calculating means for calculating is configured. This functional expression constitutes data representing the relative displacement between the bending load applied to the workpiece and the bending angle of the workpiece in accordance with the bending conditions such as the workpiece material and the target bending angle.

  In the load diagram A corresponding to the above-described functional expression, the finish angle of the workpiece W is once smaller than the target bending angle θ (= 90 degrees) with an increase in load during machining (to an acute angle smaller than 90 degrees). After that, it is shown that the target bending angle θ is around 90 degrees due to the spring back of the workpiece W or the like. Here, the load corresponding to θ = 90 degrees when the finished bending angle is smaller than 90 degrees and returns to the vicinity of 90 degrees becomes the target bending load BF when bending to 90 degrees, which is the target bending angle. The arithmetic unit 29 calculates this target bending load BF (step S4).

  Therefore, the arithmetic unit 29 includes target bending load calculating means for calculating a target bending load F for setting the bending angle of the workpiece W to the target bending angle θ based on the functional expression calculated by the functional expression calculating means. .

  Next, bending is performed on the workpiece W. At this time, the detected load data of the load sensor 25 is fed back to perform the processing until the target bending load BF is reached (step S5). When the bending process with the target bending load BF is completed, the actual bending angle (finished angle) of the workpiece W is measured (step S6). This bending angle (finished angle) is measured manually by the operator with the workpiece W once removed from the press brake 1.

  Here, as a result of measuring the actual bending angle (finished angle) of the workpiece W, it deviates from the target bending angle (90 degrees), for example, θ1 = less than θ = 90 degrees as shown in FIG. 6B. Assume a case of 89.5 degrees.

  In this case, the load function diagram A1 passing through the point Q such that the load BF1 on the load diagram A corresponding to the shifted bending angle θ1 becomes the target bending load BF is represented by a similar function equation similar to the load diagram A. (Step S7). That is, when the bending angle of the workpiece W deviates from the target bending angle θ, the arithmetic unit 29 loads the load corresponding to the bending angle θ1 deviated from the target bending angle θ in the functional equation calculated by the functional equation calculating means. The BF1 includes a function formula correcting means as a data correcting means for correcting the function formula so that the target bending load BF is obtained.

  Then, using the similarity function equation corresponding to the calculated load diagram A1, the load corresponding to the target bending angle θ is calculated as the corrected target bending load BF2 (step S8), and the calculated bending load is calculated. Bending is performed by BF2. At this time, in the same manner as described above, the load data detected by the load sensor 25 is fed back and the processing is performed until the target bending load BF2 is reached (step S9). That is, the arithmetic unit 29 includes a bending load correcting unit that calculates the bending load F2 corresponding to the target bending angle θ as the corrected target bending load based on the correction function equation corrected by the functional equation correcting unit.

  Here, in the above embodiment, the corrected target bending is performed even though the bending angle θ1 (89.5 degrees) at the initial target bending load BF is smaller than the target bending angle θ (90 degrees). The load F2 is larger than the initial target bending load BF. This is because, after the workpiece W is pressed between the punch P and the die D and reaches the final coining region, the workpiece W tends to have an outwardly open shape (the bending angle increases). . That is, after reaching the coining region, the bending angle tends to increase as the bending load increases.

  By performing the bending process with the corrected target bending load BF2, the target bending angle θ can be obtained. At this time, in the present embodiment, by simply correcting the functional expression representing the relative displacement between the bending load applied to the workpiece W and the bending angle, the bending load BF2 corresponding to the target bending angle θ is corrected to the corrected target bending load. And the work of correcting the bending load so as to obtain the target bending angle θ can be facilitated.

In this case, the target bending load BF in FIG.
BF = f _A (n, F, E, t, mold condition, θ)
Which can be expressed as
BF = f _B (θ)
Then, the calculation formula for correcting the load diagram when the load diagram A is translated up and down as shown in FIG. 6B is as follows.

BF2 = f _B (θ) + β (1)
This corresponds to offsetting the bending load.

  However, [n: strain hardening index, F: plastic coefficient, E: longitudinal elastic modulus, t: workpiece thickness, θ: target bending angle], and the die condition is the tip angle of the punch P shown in FIG. PA, the radius of curvature PR of the tip R portion of the punch P, the slope length PL of the punch P, the V width DV of the die D, and the V angle DA of the die D.

In this case, since the input value is the target bending angle θ and the bending angle at the target load BF is θ1, as information,
BF = f _B (θ)
BF = f _B '(θ1)
Since [f _B ′ (θ)] is an unknown function, [f _B ′ (θ)] is assumed to be [f _B (θ) + β] in the above equation (1). That is,
BF2 = f _B '(θ) = f _B (θ) + β
It is.

  In the above embodiment, as shown in FIG. 6B, the load diagram A is translated upward to calculate the load diagram A1 passing through the point Q similar to the load diagram A. As shown in (c), the load diagram A1 ′ passing through the point Q may be calculated by translating the load diagram A in the right direction along the horizontal axis. Also in this case, the load corresponding to the target bending angle θ can be calculated as the corrected bending load BF2 by using the similar function equation corresponding to the load diagram A1 ′ as in step S8 described above. it can.

  The calculation formula for correcting the load diagram when the load diagram A in FIG. 6C is translated in the left-right direction is as follows.

BF2 = f _B (θ + α) (2)
This is equivalent to offsetting the bending angle.

In this case, it is assumed that the above-described unknown function [f _B ′ (θ)] is [f _B (θ + α)] in the above equation (2). That is,
BF2 = f _B '(θ) = f _B (θ + α)
It is.

  Further, as an example different from FIGS. 6B and 6C, as shown in FIG. 7A, a load diagram A1 ′ passing through a point Q where the load diagram A is extended in the vertical direction is shown. You can also use '. Also in this case, the function corresponding to the load diagram A1 ″ can be used to calculate the load corresponding to the target bending angle θ as the corrected target bending load BF2.

  The corrected bending load BF2 in the example of FIG. 7A is obtained by multiplying the target bending load BF by the ratio of the load BF1 corresponding to the bending angle θ1 shifted from the target bending angle θ to the target bending load BF. Calculate with That is, BF2 = (BF ÷ BF1) × BF.

  The calculation formula for correcting the load diagram when the load diagram A in FIG. 7A is extended in the vertical direction is as follows.

BF2 = kf _B (θ) (3)
This is equivalent to proportionally multiplying the bending load. However, k (coefficient) = BF ÷ BF1.

In this case, it is assumed that the above-mentioned unknown function [f _B ′ (θ)] is [kf _B (θ)] in the above equation (3). That is,
BF2 = f _B '(θ) = kf _B (θ)
It is.

  Further, instead of the example of FIG. 7A, as shown in FIG. 7B, parameters for determining the material of the workpiece W as a bending condition input when calculating with a functional equation (for example, plastic coefficient F, It is also possible to use a load diagram A1 ′ ″ passing through the point Q where the strain hardening index n) is changed. In this case, the load corresponding to the target bending angle θ can be calculated as the corrected target bending load BF2 by using a functional expression corresponding to the load diagram A1 ".

  The calculation formula for correcting the load diagram when the load diagram A in FIG. 7B is recalculated with parameters (n ′, F ′) for determining the material of the workpiece W is as follows: Become.

BF2 = f _A (n ′, F ′, E, t, mold condition, θ) (4)
Here, n ′ is a strain hardening index calculated backward from the actual bending result, and F ′ is a plastic coefficient calculated backward from the actual bending result.

In this case, it is assumed that the above-mentioned unknown function [f _B ′ (θ)] is [f _A (n ′, F ′, E, t, mold condition, θ)] in the above equation (4). That is,
BF2 = f _B ′ (θ) = f _A (n ′, F ′, E, t, mold condition, θ)
It is.

When the above formula (4) is further described in detail, the target load BF is:
BF = f _A (n, F, E, t, mold condition, θ)
And n, F, and E are material constants.

As a result of bending the workpiece by applying the load of the target load BF, the bending angle becomes θ1,
(N ′, F ′) = f _A ⁻¹ (E, t, mold condition, θ1, BF)
Here, (n ′, F ′) is a new material constant, and the above formula (4) is obtained by recalculating using this new material constant.

  In the above-described embodiment, the case where the bending angle is smaller than the target bending angle has been described, but the corrected target bending load is calculated in the same manner when the bending angle is larger than the target bending angle. Can do. Further, in the above-described embodiment, a function equation corresponding to a theoretical value is used as data. However, data stored in the database by using experimental values in a database may be used.

1 Press brake (bending machine)
29 arithmetic unit (target bending load calculation means, data correction means, bending load correction means)
P Punch D Die W Workpiece BF Target bending load BF2 Target bending load after correction θ Target bending angle θ1 Bending angle after processing by target bending load (bending angle deviated from target bending angle)

Claims (5)

A bending apparatus that bends a plate-shaped workpiece at a target bending angle by a punch and a die, and a bending load applied to the workpiece and bending of the workpiece according to the bending conditions such as the material of the workpiece and the target bending angle. Comprising data representing relative displacement with respect to the angle, and based on this data, comprises a target bending load calculation means for calculating a target bending load for setting the bending angle of the workpiece as the target bending angle,
When the bending angle of the workpiece after bending by the target bending load calculated by the target bending load calculating means deviates from the target bending angle, a load corresponding to the bending angle deviated from the target bending angle in the data is obtained. A data correction unit that corrects the data to be the target bending load, and a bending that calculates a bending load corresponding to the target bending angle as a corrected target bending load based on the data corrected by the data correction unit. A bending apparatus comprising load correcting means.   The bending apparatus according to claim 1, wherein the data correction unit performs an operation by offsetting a bending load of the data.   The bending apparatus according to claim 1, wherein the data correction unit performs an operation by offsetting a bending angle of the data.   Assuming that the target bending load is BF and the load corresponding to the bending angle shifted from the target bending angle is BF1, the data correction unit calculates the correction data by calculating the load by (BF ÷ BF1) × BF. The bending apparatus according to claim 1.   2. The bending apparatus according to claim 1, wherein the data correction unit changes a parameter for determining a material of a workpiece among bending conditions for calculating the data when calculating the correction data.

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