Bending machine and bending angle measurement method

Abstract

To provide a bending machine that can accurately measure the bending angle regardless of whether the workpiece to be bent is a flat plate or an embossed plate. [Solution] The bending machine (91) includes a die set (8) that bends a sheet metal workpiece (W) along a predetermined bending line (Wg) by clamping it in the thickness direction; a contact plate (15) that has a flat surface (15a) and is positioned along the workpiece (W), and is capable of contacting the outer surface (Wa) of the bent workpiece (W) in a position where the flat surface (15a) is parallel to the outer surface (Wa); a support part (13) that supports the contact plate (15) so that it can rotate around an axis (CL1) parallel to the bending line (Wg); a lifting drive part (861) that lifts and lowers the support part (13) while biasing it so that the contact plate (15) is always in contact with the outer surface (Wa); and a bending angle measuring device (1) that includes an angle sensor (14) for measuring the rotation angle (θ) of the contact plate (15).

Description

Technical Field

[0001] The present invention relates to a bending machine and a bending angle measurement method.

Background Art

[0002] Patent Document 1 describes a contact-type bending angle measurement device (bending angle detection device in Patent Document 1) for measuring the bending angle of a workpiece being bent by bending processing of a bending processing device. The bending angle measurement device described in Patent Document 1 includes a pair of plate-shaped rotary detectors formed in a substantially semicircular shape so as to have a chord and rotatable.

[0003] This bending angle measurement device presses a rotary detector against each of a pair of bent surfaces of a workpiece bent in a V shape so that the chord is in close contact, and obtains the bending angle of the workpiece from the rotation angle of the rotary detector at that time.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A conventional bending angle measurement device as described in Patent Document 1 provided in a bending machine can detect the bending angle well when the workpiece is a flat plate without unevenness. On the other hand, in the case of a so-called embossed plate in which the workpiece has unevenness on the surface, depending on the uneven pattern or the size of the convex portion, a part of the chord of the rotary detector rides on the convex portion and becomes an angle different from the original bending angle of the plate, and there are cases where the correct bending angle cannot be measured. Therefore, when bending an embossed plate, an operator measures the bending angle manually, and a bending machine and a bending angle measurement method that can measure the bending angle well even for an embossed plate are desired.

Means for Solving the Problems

[0006] A first aspect of one or more embodiments is a bending machine comprising: a die assembly for bending a plate workpiece along a predetermined bending line by sandwiching it in the thickness direction; a contact plate having a flat surface and positioned along the workpiece, capable of contacting the outer surface of the bent workpiece in a position where the flat surface is parallel to the outer surface; a support portion for supporting the contact plate so as to be rotatable about an axis parallel to the bending line; a lifting drive portion for raising and lowering the support portion while biasing it so that the contact plate is always in contact with the outer surface in a position parallel to the outer surface; and a bending angle measuring device having an angle sensor for measuring the rotation angle of the contact plate.

[0007] A second aspect of one or more embodiments is a bending machine comprising: a die assembly for bending a horizontally arranged plate workpiece by clamping it vertically and bending it along a predetermined bending line; a contact plate having a flat surface and capable of contacting the outer surface of the bent workpiece in a position where the flat surface is parallel to the outer surface; a support part that supports the contact plate so as to be rotatable around an axis parallel to the bending line; a lifting drive part that lifts and lowers the support part on a predetermined lifting axis while biasing the contact plate to contact the outer surface in a position where it is always parallel to the outer surface; a displacement sensor for measuring the lifting distance of the support part; and an angle calculation part that calculates the rotation angle of the contact plate based on the lifting distance measured by the displacement sensor and the horizontal distance between the bending line and the lifting axis.

[0008] A third aspect of one or more embodiments is a method for measuring the bending angle of a workpiece, in which a workpiece of plate material having multiple protrusions with the same protruding height at their highest points is bent along a predetermined bending line by being sandwiched vertically in a bending die set with the protrusions facing downwards, using a bending angle measuring device comprising: a contact plate having a flat surface and capable of contacting the protrusions; a support part that supports the contact plate so as to be rotatable around an axis parallel to the bending line; a lifting drive unit that raises and lowers the support part while biasing the contact plate to contact the protrusions; and a sensor that outputs measurement information capable of acquiring the rotation angle of the contact plate, wherein when the contact plate is brought into contact with the protrusions, it is always brought into contact with the multiple highest points and is shaped parallel to the outer surface of the workpiece. [Effects of the Invention]

[0009] According to one or more embodiments of the bending angle measuring method and bending angle measuring apparatus, the bending angle can be measured accurately regardless of whether the workpiece to be bent is a flat plate or an embossed plate. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a side view showing the bending angle measuring device 1 according to the first embodiment of the present invention applied to the bending process of a workpiece W. [Figure 2A] Figure 2A is a side view illustrating the operation of the bending angle measuring device 1. [Figure 2B] Figure 2B is a side view illustrating the rotation angle θ measured by the bending angle measuring device 1. [Figure 2C] Figure 2C is a block diagram showing the configuration of the bending angle measuring device 1. [Figure 3] Figure 3 is a plan view of the contact plate 15 provided in the bending angle measuring device 1. [Figure 4A] Figure 4A is a plan view of the embossed steel sheet We. [Figure 4B] Figure 4B is a cross-sectional view taken at the S4B-S4B position in Figure 4A. [Figure 5A]FIG. 5A is a plan view for explaining the size of the contact plate 15 applied to the embossed steel plate We. [Figure 5B] FIG. 5B is a cross-sectional view taken at the position S5B - S5B in FIG. 5A. [Figure 6] FIG. 6 is a side view showing a state where the bending angle measuring device 1 is applied to the bending process of the embossed steel plate We. [Figure 7A] FIG. 7A is a plan view showing the embossed steel plate We1 with the second concavo-convex pattern and the contact plate 15B which is an example of a contact plate applicable thereto. [Figure 7B] FIG. 7B is a plan view showing the embossed steel plate We2 with the third concavo-convex pattern and the contact plate 15C which is an example of a contact plate applicable thereto. [Figure 8A] FIG. 8A is a partial perspective view of the bending angle measuring device 1 for explaining the attachment / detachment structure of the contact plate 15. [Figure 8B] FIG. 8B is a partial perspective view of the bending angle measuring device 1 showing a state where the contact plate 15B is mounted. [Figure 9A] FIG. 9A is a side view for explaining the measurement operation of the bending angle measuring device 1B which is a modified example of the bending angle measuring device 1. [Figure 9B] FIG. 9B is a block diagram showing the configuration of the bending angle measuring device 1B.

Embodiments for Carrying Out the Invention

[0011] The bending angle measuring device 1 according to one or more embodiments of the present invention will be described by the bending angle measuring device 1 of the first aspect.

[0012] (First Aspect) The configuration of the bending angle measuring device 1 according to the first aspect will be described with reference to FIGS. 1 to 3. FIG. 1 is a side view showing a state where the bending angle measuring device 1 according to the first aspect of the embodiment of the present invention is applied to the bending process of the work W. FIG. 2A is a side view for explaining the operation of the bending angle measuring device 1. FIG. 2B is a side view for explaining the rotation angle θ measured by the bending angle measuring device 1. FIG. 2C is a block diagram showing the configuration of the bending angle measuring device 1. FIG. 3 is a plan view of the contact plate 15 provided in the bending angle measuring device 1. For the sake of convenience of explanation, the directions of up and down, front and back are the directions indicated by the arrows in FIG. 1. Also, the left direction is the back side of the paper and the right direction is the front side of the paper.

[0013] As shown in FIG. 1, the bending angle measuring device 1 is provided in the bending machine 91 and measures the bending angle in the bending process of the work W. The work W is a flat steel plate with no unevenness on its surface. The bending machine 91 includes a lower table 83, a die set 8, and the bending angle measuring device 1. The die set 8 is a set of a die 81 and a punch die 82.

[0014] The die 81 and the punch die 82 have a shape for bending the work W at a predetermined bending angle θc. The die 81 has a groove with a V-shaped cross section that is concave downward at the upper part and is detachably fixed to the lower table 83. The punch die 82 has a convex portion with a V-shaped cross section that is convex downward at the lower part and is detachably fixed to an upper table (not shown). The upper table moves up and down so as to be separated from and approach the lower table 83.

[0015] With the above configuration, in the bending process, first, the upper table is raised (see arrow DR1a), the work W is inserted manually or by a robot hand from the front side into the gap generated between the die 81 and the punch die 82, and placed on the die 81. By lowering the upper table in this state (see arrow DR1b), the work W is sandwiched between the die and the punch die 82 and bent at a predetermined bending angle θc (see arrow DR2).

[0016] As shown in Figure 1, the bending angle measuring device 1 includes at least one pair of measuring units 10, a control unit 84, an input unit 85, and an output unit 88. In addition to these, the bending angle measuring device 1 also includes a first drive unit 86 and a second drive unit 87, as shown in Figure 2C.

[0017] The control unit 84 includes a CPU (Central Processing Unit) 841, a storage unit 842, an angle acquisition unit 843, and a determination unit 844. The first drive unit 86 includes a lifting drive unit 861 and a horizontal drive unit 862. The second drive unit 87 includes a lifting drive unit 871 and a horizontal drive unit 872.

[0018] The same measuring unit 10 is positioned on both the front and rear sides of the mold assembly 8. Hereafter, when distinguishing between them, they will be referred to as the front measuring unit 10F and the rear measuring unit 10R. Measuring unit 10F will also be referred to as the first measuring unit 10F, and measuring unit 10R as the second measuring unit 10R. The configuration of the measuring unit 10 will be described below using measuring unit 10F as a representative example.

[0019] The measuring unit 10 (10F) comprises a main body 11, a lifting unit 12, a support unit 13, an angle sensor 14, and a contact plate 15. The main body 11 is mounted on the lower table 83 or a component integrated with the lower table 83, and is movable to any position in the front-rear direction by the horizontal drive unit 862 (see Figure 2C) of the first drive device 86 (see arrow DR3).

[0020] The lifting section 12 extends upward from the main body 11 and is raised and lowered by the lifting drive unit 861 of the first drive unit 86 (see Figure 2C). The support section 13 is fixed to the upper part of the lifting section 12, and an angle sensor 14 (14F) is attached to its tip so as to be rotatable around an axis CL1 extending in the left-right direction. A contact plate 15 (15F) is integrally attached to the angle sensor 14 as the rotor to be measured. The angle sensor 14 measures the rotation angle of the contact plate 15 around the axis CL1 and outputs the angle information Jf to the control unit 84 (see Figure 2C). The contact plate 15 is formed in a rectangular shape in plan view, for example, as shown in Figure 3.

[0021] The measuring unit 10R has a similar structure and measures the rotation angle of the contact plate 15 (15R) using the angle sensor 14 (14R), and outputs the angle information Jr to the control unit 84 (see Figure 2C).

[0022] The angle acquisition unit 843 of the control unit 84 stores the angle of the angle information Jf output from the angle sensor 14 as a reference angle θa in the storage unit 842 when the flat surface 15a of the contact plate 15 is in a horizontal plane Ph (see Figure 2B). Then, it acquires the difference between the measured angle θb when the contact plate 15 is rotated and tilted at an arbitrary angle and the reference angle θa stored in the storage unit 842 as the rotation angle θ of the contact plate 15.

[0023] As shown in Figure 2A, the measuring unit 10 has a lifting section 12 that moves up and down relative to the main body 11 (see arrow DR41), and the contact plate 15, which is the rotor of the angle sensor 14, is allowed to rotate freely around the axis CL1 (see arrow DR42). As shown in Figure 2B, the angle sensor 14 sends the measured angle θb of the contact plate 15 to the control unit 84.

[0024] The bending process of the workpiece W and the measurement of the bending angle θc of the workpiece W using the bending angle measuring device 1 described above are performed as follows. The workpiece W is a flat steel plate without any irregularities. The workpiece W is not limited to a steel plate, as long as it is a metal sheet material.

[0025] In Figure 1, first, the bending machine 91 raises the punch die 82 in response to an instruction from the operator via the input unit 85 (see DR1a). A flat workpiece W is then inserted and set between the punch die 82 and the die die 81 to a predetermined insertion position. At this time, the workpiece W is placed on the upper surface 81a of the die die 81. The predetermined insertion position is the position where the bending line Wg set on the workpiece W coincides with the bending position Pb of the die assembly 8. The bending machine 91 may also be equipped with a butt device (not shown) that allows the workpiece W to be butted against the butt device for positioning.

[0026] Once the workpiece W is set, the operator inputs an instruction to execute the bending process into the input unit 85. This causes the punch die 82 to descend (see arrow DR1b), and the workpiece W is bent into a V-shape. Hereafter, the part of the bent workpiece W in front of the bending position Pb (bending line Wg) will be referred to as the front workpiece Wf, and the part behind it will be referred to as the rear workpiece Wr.

[0027] The lifting section 12 of the measuring unit 10 is biased upward by the lifting drive unit 861 with a small force that does not affect the bending process. Therefore, when the workpiece W is bent, the contact plate 15 maintains close contact with the outer surface Wa, which is the lower surface of the workpiece W, and follows the bending, so the angle sensors 14F and 14R output angle information Jf and Jr, corresponding to the bent angles of the front workpiece Wf and rear workpiece Wr, respectively, to the control unit 84.

[0028] The angle acquisition unit 843 of the control unit 84 acquires the front bending angle θcf, which is the bending angle θc of the front workpiece Wf, based on the angle information Jf from the measuring unit 10f, and acquires the rear bending angle θcr, which is the bending angle θc of the rear workpiece Wr, based on the angle information Jr from the measuring unit 10R. Next, the angle acquisition unit 843 acquires the bending angle θc of the workpiece W using (Equation 1). Here, the units of θc, θcf, and θcr are (°).

[0029] θc=180°-(θcf+θcr) (Formula 1)

[0030] The determination unit 844 of the control unit 84 determines whether the bending angle θc acquired by the angle acquisition unit 843 conforms to the bending angle specification of the workpiece W set for bending using this mold assembly 8, and outputs the result from the output unit 88.

[0031] By using the measuring unit 10 having the freely rotatable contact plate 15 as described above, the bending angle can be measured with high precision not only for flat plate materials but also for so-called embossed steel plates We that have protrusions W1 on their surface. The bending process of this workpiece We (embossed steel plate We) will now be explained with reference to Figures 4A to 6. Figure 4A is a plan view of the embossed steel plate We. Figure 4B is a cross-sectional view at position S4B-S4B in Figure 4A. Figure 5A is a plan view illustrating the size of the contact plate 15 applied to the embossed steel plate We. Figure 5B is a cross-sectional view at position S5B-S5B in Figure 5A. The bending process of the embossed steel plate We described here is a bending process where the embossed side (the side where the protrusions W1 are formed) is on the outside.

[0032] As shown in Figures 4A and 4B, the embossed steel sheet We has protrusions W1 that are approximately elliptical in shape when viewed from above, formed in a predetermined arrangement pattern known as a staggered pattern across its entire surface. The thickness of the portion of the embossed steel sheet We where the protrusions W1 are not formed is Wt, and the central part of the protrusions W1 is the highest point Pt, which has a protrusion height W1t. The embossed steel sheet We used for bending is specified so that the protrusion height W1t of at least the highest point Pt is a constant value with high precision. That is, as shown in Figure 4B, the plane He containing the three highest points Pt that are not on a straight line is parallel to the outer surface Wea of ​​the portion of the embossed steel sheet We where the protrusions W1 are not formed.

[0033] When bending the embossed steel sheet We, the contact plate 15 shall be of the size shown in Figures 5A and 5B, for example. Specifically, it shall be sized and shaped to be able to contact two or more of the highest points Pt of the protrusion W1. For example, the contact plate 15 shall be able to contact at least three highest points Pt that are not in a straight line. As a result, the contact plate 15 shall always be in contact with multiple highest points Pt and become parallel to the outer surface Wea of ​​the embossed steel sheet We.

[0034] By using the measuring unit 10 for bending workpieces W made of embossed steel sheet We, the bending angle can be measured with high precision. An example of this will be explained with reference to Figure 6. Figure 6 is a side view showing the bending angle measuring device 1 applied to the bending of embossed steel sheet We. In other words, it is a side view in which the bending of workpiece W, which is not embossed, is replaced with a workpiece W made of embossed steel sheet We, as shown in Figure 1.

[0035] As shown in Figure 6, the contact plate 15 contacts multiple different highest points Pt of the convex portion W1 of the embossed steel sheet We, resulting in an angle corresponding to the plane He. Since the plane He is the same angle as the outer surface Wea of ​​the embossed steel sheet We, the front bending angle θcf and the rear bending angle θcr are obtained based on the angles measured by the measuring units 10f and 10R, and from there, the bending angle θc can be obtained using (Equation 1) in the same way as in the case of the workpiece W.

[0036] The embossed steel sheet We is not limited to having a substantially elliptical shape in plan view of the aforementioned protrusions W1, but may be formed in various patterns. Two examples will be explained with reference to Figures 7A and 7B. Figure 7A is a plan view showing an embossed steel sheet We1 with a second uneven pattern and a contact plate 15B, which is a modified example of a contact plate 15 applicable thereto. Figure 7B is a plan view showing an embossed steel sheet We2 with a third uneven pattern and a contact plate 15C, which is a modified example of a contact plate applicable thereto.

[0037] The embossed steel plate We may be, for example, an embossed steel plate We1 with an embossed pattern (second relief pattern), also known as a checkered steel plate, as shown in Figure 7A. The contact plate 15 may be rectangular in shape in plan view, as described above, or it may be a circular contact plate 15B as shown in Figure 7A.

[0038] Furthermore, the embossed steel plate We may be formed with a pattern (third uneven pattern) in which circular protrusions W1 are arranged in a grid in a plan view, as shown in Figure 7B. Also, the contact plate 15 may be inclined rectangular shape. Both contact plate 15B and contact plate 15C are sized to always make contact with the three highest points Pt that are not on a straight line.

[0039] To accommodate various types of embossed steel plates We, the contact plate 15 should be designed to be interchangeably attached to the angle sensor 14. Figure 8A is a partial perspective view of the measurement unit 10 illustrating an example of the attachment / detachment structure of the contact plate 15. Figure 8B is a partial perspective view of the measurement unit 10 showing the contact plate 15B attached.

[0040] As shown in Figure 8A, the angle sensor 14 is provided with a support plate 141 for fixing the contact plate 15, and the support plate 141 has female threads formed at its four corners. The contact plate 15 is fastened by countersunk screws N that are screwed into the female threads of the support plate 141. The contact plate 15 has a counterbore (not shown) so that the countersunk screws N do not protrude from the surface 15a. Due to this structure, as shown in Figure 8B, the contact plate 15 can be replaced with one of other shapes, such as a circular contact plate 15B. The angle sensor 14, to which the contact plates 15 and 15B are detachably attached, is rotatable around the axis CL14. The mounting structure of the contact plate 15 is not limited to the screw fastening structure described above. For example, the contact plate 15 may be attached to the support plate 141 with adhesive tape. Alternatively, a dovetail groove or T-shaped groove may be formed on one of the contact plate 15 and the support plate 141, and a projection that engages with the groove may be formed on the other so that the contact plate 15 can be slidably attached to the support plate 141 by interlocking grooves.

[0041] (Second aspect) Next, the bending angle measuring device 1B of the second embodiment will be described, mainly in terms of its differences from the first embodiment, with reference to Figures 9A and 9B. Figure 9A is a side view illustrating the measurement operation of the bending angle measuring device 1B, a modified example of the bending angle measuring device 1. Figure 9B is a block diagram showing the configuration of the bending angle measuring device 1B.

[0042] The bending angle measuring device 1B of the second embodiment differs from the bending angle measuring device 1 of the first embodiment in that it has a measuring unit 10B instead of the measuring unit 10, and a control unit 84B instead of the control unit 84.

[0043] The measurement unit 10B differs from the measurement unit 10 in that it is equipped with a displacement sensor 17 instead of an angle sensor 14. Specifically, in Figure 9A, the displacement sensor 17 is located inside the main body 11, and the rod of the displacement sensor 17 is the lifting part 12, which is raised and lowered by the lifting drive unit 861. That is, the displacement sensor 17 measures the lifting distance of the lifting part 12 and sends the measurement result as distance information JS to the control unit 84B.

[0044] The displacement sensor 17 consists of a first displacement sensor 17F corresponding to the front workpiece Wf and a second displacement sensor 17R corresponding to the rear workpiece Wr, which are positioned on the front and rear sides of the mold assembly 8, respectively. The first displacement sensor 17F outputs distance information JSf corresponding to the front workpiece Wf, and the second displacement sensor 17R outputs distance information JSr corresponding to the rear workpiece Wr. The contact plate 15 is simply attached to the upper end of the lifting section 12 so as to be freely rotatable.

[0045] As shown in Figure 9B, the control unit 84B differs from the control unit 84 in that it has an angle acquisition unit 845 instead of an angle acquisition unit 843. The angle acquisition unit 845 includes a horizontal position acquisition unit 8451, a convexity acquisition unit 8452, and an angle calculation unit 8453.

[0046] Next, a method for measuring the bending angle of a workpiece W using a measurement unit 10 equipped with a displacement sensor 17 in the bending angle measuring device 1B will be described. As shown in Figure 9A, the reference position in the front-rear direction of the main body 11 is defined as the lifting axis CL17, which is the axis extending vertically from the lifting part 12 of the displacement sensor 17, and the distance in the front-rear direction between the lifting axis CL17 and the bending position Pb is defined as distance L1. The axis of rotation CL1 of the contact plate 15 is on the lifting axis CL17. The lifting part 12 is biased by the displacement sensor 17 to move upward with a small force. As a result, the contact plate 15 is in close contact with the lower surface of the workpiece W regardless of the degree of bending of the workpiece W.

[0047] First, assuming the workpiece W is in a horizontal position before bending, the displacement sensor 17 measures the distance h0 from the height position H of the axis CL1 at the 0 (zero) point of the displacement sensor 17, where the contact plate 15 is not in contact with the workpiece W, to the height position Ha of the axis CL1 when the contact plate 15 is in close contact with the workpiece W, and sends this distance information JS to the control unit 84. The angle acquisition unit 845 of the control unit 84B uses this height position as the reference height Ha and stores the distance at the reference height Ha in the storage unit 842.

[0048] On the other hand, the horizontal position acquisition unit 8451 of the control unit 84B acquires in advance the distance L1 in the front-rear direction between the axis CL1 and the bending position Pb, which is the position of the bending line Wg, from the encoder information of the horizontal drive unit 862.

[0049] When the workpiece W is bent to position PB1 by the bending process, the height position of the axis CL1 rises by a height h1 while allowing rotation of the contact plate 15 that is in close contact with the lower surface of the workpiece W. Similarly, when the workpiece W is bent to positions PB2 and PB3, respectively, the height position of the axis CL1 rises by heights h2 and h3, respectively. This rise distance is input from the displacement sensor 17 to the control unit 84B and acquired by the convexity acquisition unit 8452 of the control unit 84B.

[0050] The angle calculation unit 8453 uses the distance L1 acquired by the horizontal position acquisition unit 8451 and the heights h1 to h3 acquired by the convexity acquisition unit 8452, and uses (Equation 2) to calculate the rotation angles θ1 to θ3 due to bending of the workpiece W at each height h1 to h3. That is, the angle calculation unit 8453 calculates the rotation angle θk at an arbitrary height hk (k: positive integer), θk=arctan(hk / L1) (Formula 2) We will seek it as follows.

[0051] The bending angle measuring device 1B is equipped with measuring units 10BF and 10BR before and after the bending position Pb, respectively. Measuring units 10BF and 10BR acquire the rotation angles θk due to bending of the front workpiece Wf and the rear workpiece Wr, respectively, using the method described above. The angle acquisition unit 845 then calculates the bending angle θc of the workpiece W using (Equation 1), similar to the bending angle acquisition method of the bending angle measuring device 1. Even if the workpiece W is an embossed steel plate We, the bending angle measuring device 1B can acquire the rotation angles θk of the front workpiece Wef and the rear workpiece Wer, and calculate the bending angle θc in the same way as a flat plate material without irregularities.

[0052] One aspect of the present invention is not limited to the configuration and procedure described above, and may be modified without departing from the spirit of the invention.

[0053] Instead of the embossed steel plate We, an embossed plate of another metal may be used as the workpiece W. Furthermore, a single protrusion W1 may have multiple apex points Pt with the same protrusion height.

[0054] As described in detail above, the first aspect of one or more embodiments of the present invention is a bending machine 91 comprising: a die assembly 8 for bending a sheet metal workpiece W along a predetermined bending line Wg by sandwiching it in the thickness direction; a contact plate 15 having a flat surface 15a and positioned along the workpiece W, and capable of contacting the outer surface Wa of the bent workpiece W in a position where the flat surface 15a is parallel to the outer surface Wa; a support part 13 for supporting the contact plate 15 so as to be rotatable around an axis CL1 parallel to the bending line Wg; a lifting drive unit 861 for raising and lowering the support part 13 while biasing it so that the contact plate 15 is always in contact with the outer surface Wa in a position where it is parallel to the outer surface Wa; and a bending angle measuring device 1 having an angle sensor 14 for measuring the rotation angle θ of the contact plate 15.

[0055] According to this first embodiment, the bending angle can be accurately measured regardless of whether the workpiece is a flat plate or an embossed plate.

[0056] A second aspect of one or more embodiments of the present invention comprises a die assembly 8 for bending a horizontally arranged plate workpiece W by sandwiching it vertically along a predetermined bending line Wg; a contact plate 15 having a flat surface 15a and capable of contacting the outer surface Wa of the bent workpiece W in a position where the flat surface 15a is parallel to the outer surface Wa; a support portion 13 that supports the contact plate 15 so as to be rotatable around an axis CL1 parallel to the bending line Wg; and the support portion 13 being supported by the contact plate 15 The bending machine 91 is equipped with a bending angle measuring device 1B which has a lifting drive unit 861 that lifts and lowers along a predetermined lifting axis CL17 while biasing it to contact the outer surface Wa in a position that is always parallel to it, a displacement sensor 17 that measures the lifting distance of the support unit 13, and an angle calculation unit 8453 that calculates the rotation angle θ of the contact plate 15 based on the lifting distance measured by the displacement sensor 17 and the horizontal distance L1 between the bending line Wg and the lifting axis CL17.

[0057] This second embodiment also allows for accurate measurement of the bending angle regardless of whether the workpiece is a flat plate or an embossed plate.

[0058] A third aspect of one or more embodiments of the present invention is a method for measuring the bending angle of a workpiece, in which a workpiece We of a plate material having multiple protrusions W1 with the same protruding height W1t at its highest point Pt is held in a position with the protrusions W1 facing downwards, clamped vertically in a mold assembly 8, and bent along a predetermined bending line Weg, using a bending angle measuring device 1 which has a plate shape having a flat surface 15a and capable of contacting the protrusions W1, a support part 13 that supports the contact part 15 so as to be rotatable around an axis CL1 parallel to the bending line Weg, a lifting drive unit 861 that lifts and lowers the support part 13 while biasing the contact part 15 to contact the protrusions W1, and a sensor 14 that outputs measurement information capable of acquiring the rotation angle θ of the contact part 15, wherein when the contact part 15 is brought into contact with the protrusions W1, it always comes into contact with the multiple highest points Pt and becomes a shape parallel to the outer surface Wea of ​​the workpiece We.

[0059] This third embodiment also allows for accurate measurement of the bending angle regardless of whether the workpiece is a flat plate or an embossed plate.

[0060] In a third embodiment, the sensor may be an angle sensor 14 that measures the rotation angle θ of the contact plate 15.

[0061] This allows the rotation angle of the workpiece to be directly measured as the rotation angle of the contact plate, which is equal to the workpiece's rotation angle.

[0062] In a third embodiment, the sensor may be a displacement sensor 17 that measures the vertical distance of the support portion 13.

[0063] This allows for the attachment of a contact plate with a larger shape and mass equal to the mass of the angle sensor. [Explanation of Symbols]

[0064] 1.1B Bending Angle Measuring Device 10 10F, 10R, 10B, 10BF, 10BR Measurement Unit 11 Main body 12 Lifting section 13 Support part 14, 14F, 14R Angle Sensor 141 Support plate 15,15F,15R,15B,15C Contact plate 15a Surface (flat surface) 17, 17F, 17R Displacement Sensors 8 Mold set 81 Die mold 81a Top side 82 Punch molds 83 Lower Table 84,84B Control Unit 841 CPU (Central Processing Unit) 842 Storage section 843,845 Angle acquisition part 844 Judgment section 8451 Horizontal position acquisition unit 8452 Convexity acquisition part 8453 Angle calculation unit 85 Input section 86 First drive unit 861 Lifting drive unit 862 Horizontal drive unit 87 Second drive unit 871 Lifting drive unit 872 Horizontal drive unit 88 Output section 91 Bending machine CL1,CL14 axis line CL17 Lifting axis Ha standard height He plane H Height position h1~h3 Height Jf,Jr angle information JS,JSf,JSr distance information L1 distance N Countersunk screw PB1~PB3 position Pb bending position Ph horizontal plane Pt Top sW Work Wa surface (outer surface) We, We1, We2 Embossed steel sheet Wea surface (outer surface) Wg, Weg folding line Wf, Wef Front workpiece Wr,Wer rear workpiece Wt plate thickness W1 protrusion W1t Projection height θ,θ1~θ3,θk Rotation angle θa Reference angle θb Measurement angle θc bending angle θcf Front bending angle θcr Rear bending angle

Claims

1. A die assembly that holds a sheet metal workpiece in the thickness direction and bends it along a predetermined bending line, A bending angle measuring device comprising: a contact plate having a flat surface and positioned along the workpiece, capable of contacting the outer surface of the bent workpiece in a position where the flat surface is parallel to it; a support portion that supports the contact plate so as to be rotatable about an axis parallel to the bending line; a lifting drive portion that raises and lowers the support portion while biasing it so that the contact plate is always in contact with the outer surface in a position parallel to it; and an angle sensor for measuring the rotation angle of the contact plate. A bending machine equipped with a bending process.

2. A die assembly that clamps a horizontally positioned plate material workpiece vertically and bends it along a predetermined bending line, A bending angle measuring device comprising: a contact plate having a flat surface and capable of contacting the outer surface of the bent workpiece in a position where the flat surface is parallel to the outer surface; a support part that supports the contact plate so as to be rotatable about an axis parallel to the bending line; a lifting drive part that lifts and lowers the support part on a predetermined lifting axis while biasing the contact plate to contact the outer surface in a position where it is always parallel to the outer surface; a displacement sensor for measuring the lifting distance of the support part; and an angle calculation part that calculates the rotation angle of the contact plate based on the lifting distance measured by the displacement sensor and the horizontal distance between the bending line and the lifting axis; A bending machine equipped with a bending process.

3. When performing a bending process on a plate material workpiece having multiple protrusions with the same protruding height at their highest point, by positioning the protrusions downwards and clamping it vertically in a die assembly and bending it along a predetermined bending line, A bending angle measuring device is used, which comprises a contact plate having a flat surface and capable of contacting the protrusion, a support part that supports the contact plate so as to be rotatable around an axis parallel to the bending line, a lifting drive unit that raises and lowers the support part while biasing the contact plate to contact the protrusion, and a sensor that outputs measurement information capable of acquiring the rotation angle of the contact plate. A method for measuring the bending angle of a workpiece, wherein when the contact plate is brought into contact with the convex portion, it is always brought into contact with multiple of the highest points and is shaped to be parallel to the outer surface of the workpiece.

4. The method for measuring the bending angle of a workpiece according to claim 3, wherein the sensor is an angle sensor for measuring the rotation angle of the contact plate.

5. The method for measuring the bending angle of a workpiece according to claim 3, wherein the sensor is a displacement sensor for measuring the lifting distance of the support portion.

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