Press brake, bending processing system, and method for controlling sensor movement

Abstract

A press brake includes an upper tool and a lower tool that are movable relative to each other, a height detection sensor configured to be able to detect a position of a workpiece in a height direction, the workpiece being inserted between the upper tool and the lower tool, a height detection sensor moving part configured to move the height detection sensor in a longitudinal direction of the upper tool and the lower tool, and a control unit. The control unit includes a movement control unit configured to move the height detection sensor to a vicinity of a position of workpiece holding means configured to hold the workpiece, and a height determination processing unit configured to determine whether or not the position of the workpiece in the height direction detected by the height detection sensor falls within an allowable range.

Description

Technical Field

[0001] The present invention relates to a press brake, a bending system, and a sensor movement control method.Background Art

[0002] There is a conventional bending system that includes: a press brake that includes a punch and a die for carrying out bending of a plate-shaped workpiece having a predetermined length, and a back gauge that positions the workpiece in a front-rear direction; a transfer robot that transfer-positions the workpiece with respect to a position of the bending by the punch and the die; and a control device for controlling an operation of the transfer robot and the back gauge (Patent Literature 1, etc.).

[0003] In such a bending system, the transfer robot that transfers and supplies a workpiece W between the punch and the die is arranged in front of the press brake to allow movement in the front-rear direction, the left-right direction, and the up-down direction.Citation ListPatent Literature

[0004] Patent Literature 1: JP 2014-147955 ASummary of InventionTechnical Problem

[0005] However, in a conventional bending system, when transfer-positioning a workpiece, although the positioning of the workpiece in the front-rear direction can be performed using the back gauge, the positioning in the up-down direction requires an operator to manually position the workpiece while conducting a visual check in a vicinity of the transfer robot or workpiece.

[0006] The time taken for the positioning in the up-down direction is influenced by the operator's experience and intuition, and inexperienced operators often have to repeat a visual check and an adjustment while confirming the gaps between the workpiece and the punch and between the workpiece and the die, leading to issues such as hindering the high operation efficiency of the bending system and operation concentration on skilled operators.

[0007] One aspect of the present invention provides a press brake, a bending system, and a sensor movement control method that allow positioning in a height direction of a workpiece without conducting a visual check in a vicinity of the workpiece to be subjected to bending.Solution to Problem

[0008] A press brake according to one aspect of the present invention includes an upper tool and a lower tool that are movable relative to each other, a height detection sensor configured to be able to detect a position of a workpiece in a height direction, the workpiece being inserted between the upper tool and the lower tool, a height detection sensor moving part configured to move the height detection sensor in a longitudinal direction of the upper tool and the lower tool, and a control unit. The control unit includes a movement control unit configured to move the height detection sensor to a vicinity of a position of workpiece holding means configured to hold the workpiece, and a height determination processing unit configured to determine whether or not the position of the workpiece in the height direction detected by the height detection sensor falls within an allowable range.

[0009] A bending system according to one aspect of the present invention includes a press brake configured to carry out bending of a plate-shaped workpiece having a predetermined length, a workpiece supply robot configured to supply the workpiece to the press brake, a height detection sensor, a height detection sensor moving part, and a control device configured to control the press brake, the workpiece supply robot, the height detection sensor, and the height detection sensor moving part. The press brake includes an upper tool and a lower tool that are movable relative to each other. The workpiece supply robot is configured to insert the workpiece between the upper tool and the lower tool. The height detection sensor is configured to be able to detect a position of the workpiece in a height direction, the workpiece being inserted between the upper tool and the lower tool. The height detection sensor moving part is configured to move the height detection sensor in a longitudinal direction of the upper tool and the lower tool. The control device includes a movement control unit configured to move the height detection sensor to a vicinity of a position of workpiece holding means configured to hold the workpiece, and a height determination processing unit configured to determine whether or not the position of the workpiece in the height direction detected by the height detection sensor falls within an allowable range.

[0010] A sensor movement control method according to one aspect of the present invention includes moving a height detection sensor to a vicinity of a position of workpiece holding means, the height detection sensor being configured to be able to detect a position of a workpiece in a height direction, the workpiece holding means being configured to hold a workpiece inserted between an upper tool and a lower tool that are movable relative to each other, detecting the position of the workpiece in the height direction, and determining whether or not the position of the workpiece in the height direction detected by the height detection sensor falls within an allowable range.

[0011] According to the press brake, the bending system, and the sensor movement control method according to one aspect of the present invention, whether or not the position of the workpiece in the height direction detected by the height detection sensor falls within the allowable range is determined, and thus it is possible to position the workpiece in the height direction without conducting a visual check in the vicinity of the workpiece to be subjected to bending.Advantageous Effect of Invention

[0012] According to the press brake, the bending system, and the sensor movement control method according to one aspect of the present invention, positioning of the workpiece in the height direction can be performed without conducting a visual check in the vicinity of the workpiece to be subjected to bending.Brief Description of Drawings

[0013] [Figure 1] Figure 1 is a schematic diagram illustrating a bending system according to an embodiment of the present invention. [Figure 2] Figure 2 is a schematic diagram illustrating a modified example of the bending system in the present embodiment. [Figure 3] Figure 3 is a schematic diagram illustrating a modified example of a robotic hand in the present embodiment. [Figure 4] Figure 4 is a front view illustrating a press brake in the present embodiment. [Figure 5] Figure 5 is a functional block diagram illustrating a control device in the present embodiment. [Figure 6] Figure 6 is a schematic diagram illustrating an example of a positional relationship between a height detection sensor and the robotic hand in the present embodiment. [Figure 7] Figure 7 is a schematic diagram illustrating an example of the positional relationship between the height detection sensor and the robotic hand in the present embodiment. [Figure 8] Figure 8 is a schematic diagram illustrating an example of the positional relationship between the height detection sensor and the robotic hand in the present embodiment. [Figure 9] Figure 9 is a schematic diagram illustrating an example of the positional relationship between the height detection sensor and the robotic hand in the present embodiment. [Figure 10] Figure 10 is a schematic diagram illustrating an example of an operation of the bending system in the present embodiment. [Figure 11] Figure 11 is a schematic diagram illustrating an example of the operation of the bending system in the present embodiment. [Figure 12] Figure 12 is a schematic diagram illustrating an example of the operation of the bending system in the present embodiment. [Figure 13] Figure 13 is a schematic diagram illustrating an example of the operation of the bending system in the present embodiment. [Figure 14] Figure 14 is a flowchart illustrating an example of a sensor movement control method in the present embodiment. [Figure 15] Figure 15 is a flowchart illustrating an example of a bending method in the present embodiment. Description of Embodiment

[0014] The best embodiment for carrying out the present invention will be described below with reference to the drawings. It should be noted that the following embodiment does not limit the invention according to each claim, and not all combinations of features described in the embodiment are essential for the solution of the invention.[Overall Configuration of Bending System According to the Present Embodiment]

[0015] Figure 1 is a schematic diagram illustrating a bending system according to an embodiment of the present invention. Figure 4 is a front view illustrating a press brake in the present embodiment.

[0016] First, with reference to Figures 1 and 4, a bending system 1 according to an embodiment of the present invention will be schematically described. The bending system 1 according to the present embodiment, as illustrated in Figures 1 and 4, includes a press brake 10 that carries out bending of a plate-shaped workpiece W having a predetermined length, a workpiece supply robot 100 that supplies the workpiece W to the press brake 10, a height detection sensor 20, a height detection sensor moving part 40, and a control device 200 that controls the press brake 10, the workpiece supply robot 100, the height detection sensor 20, and the height detection sensor moving part 40. The height detection sensor 20 and the control device 200 function as sensor movement control devices.

[0017] In addition, the bending system 1 may further include a workpiece mounting table P on which a plurality of workpieces W before processing are mounted. The workpiece mounting table P is not limited to a flat platform and may be a portable pallet, a loading device, or a Kushiba stand, etc. In addition, the bending system 1 may include a robot or device that delivers the workpiece W to the workpiece supply robot 100 instead of the workpiece mounting table P. The press brake 10 includes an upper tool U and a lower tool L that are provided to face each other. In the present embodiment, the press brake 10 includes the upper tool U as a punch and the lower tool L as a tool, but is not limited thereto, and the upper tool U may be a tool and the lower tool L may be a punch.

[0018] In the following description, a "Z-axis direction (height direction)" refers to a direction in which the upper tool U and the lower tool L face each other, with the upper tool U positioned vertically above the lower tool L. Also, an "X-axis direction (longitudinal direction of the upper tool U and the lower tool L)" means the left-right direction orthogonal to the Z-axis when facing the front surface of the press brake 10, and a "Y-axis direction" means the depth direction orthogonal to the Z-axis and X-axis in this case.[Configuration of Workpiece Supply Robot]

[0019] The workpiece supply robot 100 is arranged between the workpiece mounting table P and the press brake 10, and is configured to supply the workpiece W between the upper tool U and the lower tool L as workpiece holding means. It is preferable that the workpiece supply robot 100 is provided to face the upper tool U and the lower tool L of the press brake 10, but the present invention is not limited thereto.

[0020] The workpiece supply robot 100 is configured to hold an uppermost workpiece W among the plurality of workpieces W stacked on the workpiece mounting table P and to supply (insert) the workpiece W to the press brake 10, and is also configured to perform a following operation during the bending by the press brake 10. In addition, the workpiece supply robot 100 is configured to transfer (carry out) the workpiece W to a predetermined location after the bending.

[0021] Specifically, as illustrated in Figure 1, the workpiece supply robot 100 includes a robotic hand 120 that can hold the workpiece W as a workpiece holding part, and an arm part 140 that causes the robotic hand 120 to approach or separate from the workpiece W. In addition, the workpiece supply robot 100 may further include a moving mechanism 160 for moving the workpiece supply robot 100.

[0022] Figure 2 is a schematic diagram illustrating a modified example of the bending system in the present embodiment.

[0023] The robotic hand 120 is detachably attached to a distal end of the arm part 140, as illustrated in Figure 1. The robotic hand 120 may have a hand main body 122 that grips the workpiece W, or as illustrated in Figure 2, it may have a hand main body 122' that is detachably attached to the distal end of the arm part 140, and a plurality of suction parts 124 attached to the hand main body 122' and configured to be able to hold the workpiece W.

[0024] Figure 3 is a schematic diagram illustrating a modified example of the robotic hand in the present embodiment.

[0025] The hand main body 122' includes, as illustrated in Figure 3, an attachment part 122a that is detachably attached to the distal end of the arm part 140, a first support bar 122b coupled to the attachment part 122a, and a plurality of second support bars 122c provided to the first support bar 122b to be spaced apart in the longitudinal direction of the first support bar 122b. Note that a shape of the hand main body 122, 122' is not limited to an illustrated example, and can be arbitrarily changed in accordance with a shape and the like of the workpiece W.

[0026] The suction parts 124 are attached to both ends of each of the second support bars 122c, and are each connected via piping to an air suction source (not illustrated) that sucks air. Each of the suction parts 124 includes, at a lower end thereof, a flat suction pad that can suck (can contact) a surface of the workpiece W, and is configured to suck the surface of the uppermost workpiece W from the plurality of workpieces W stacked on the workpiece mounting table P with a suction force of the air generated by the air suction source. Note that the robotic hand 120 can employ various known configurations, and thus detailed description thereof will be omitted. Furthermore, the robotic hand 120 is not limited to the embodiment described above, and various known configurations can be arbitrarily employed.

[0027] One end of the arm part 140 is connected to a base table 160b of the moving mechanism 160, the other end thereof is connected to the robotic hand 120, and the arm part 140 is configured to cause the robotic hand 120 to approach or separate from the workpiece W based on the control signal from a robot control unit 230 of the control device 200. In the present embodiment, the arm part 140 is an articulated arm including six control axes, and is configured to be able to execute not only transfer of the workpiece W from the workpiece mounting table P but also supply (insertion) of the workpiece W to a processing machine or the like, assistance in the processing (bending process) of the workpiece W, and transfer (carrying-out) of a product (bent part) from the processing machine or the like. Note that the arm part 140 can employ various known configurations, and thus detailed description thereof will be omitted. Furthermore, the arm part 140 is not limited to the configuration of the articulated arm including the six control axes described above, and various known configurations can be arbitrarily employed.

[0028] The moving mechanism 160 is a so-called linear motion mechanism that includes a rail part 160a laid on a floor surface, the base table 160b that is movable on and along the rail part 160a, and base table driving means (not illustrated) that drives the base table 160b, and is configured to move the workpiece supply robot 100 on the floor surface based on a control signal from the robot control unit 230, which will be described later, of the control device 200. Note that the moving mechanism 160 can employ various known configurations, and thus detailed description thereof will be omitted.[Configuration of Press Brake]

[0029] The press brake 10, as illustrated in Figure 4, includes an upper table 11 and a lower table 12 which are aligned and arranged in the height direction (Z-axis direction) at a center of the front surface such that each one surface in the depth direction (Y-axis direction), for example, the outer plate surface, faces the front, and support parts 13 that support the upper table 11 and the lower table 12 and are arranged on the left and right sides.

[0030] In addition, as illustrated in Figure 1, the press brake 10 includes a drive mechanism 16 configured to reciprocate the upper table 11 along the height direction relative to the lower table 12, and a position detection sensor (not illustrated) that detects a movement position when the upper table 11 is moved by the drive mechanism 16, for example.

[0031] Furthermore, the press brake 10 includes a back gauge 17 that positions the workpiece W in the depth direction inserted between the upper tool U and the lower tool L, and an angle detection sensor 18 that can detect a bending angle of the workpiece W during the bending of the workpiece W.

[0032] In the following description, the basic configuration of the press brake 10 can adopt various known configurations, and thus detailed description thereof will be omitted.

[0033] The upper table 11 is made of a plate-shaped member such as metal, and includes a plurality of upper tool holders (punch holders) 14 that hold the upper tool U such as a punch at its lower portion. The lower table 12 is made of a plate-shaped member such as metal similar to the upper table 11, and includes a lower tool holder (tool holder) 15 that holds the lower tool L such as a tool at its upper portion. In the case where the upper tool U is the tool and the lower tool L is the punch, the upper tool holders 14 become the tool holders, and the lower tool holder 15 becomes the punch holder.

[0034] Each support part 13, in the present embodiment, is formed of a plate-shaped side frame formed in a substantially U-shape in a side view, but is not limited thereto, and may be formed of a rod-shaped tie bar or the like.

[0035] The drive mechanism 16 is, for example, a hydraulic cylinder that serves as a driving source for the upper table 11, and is attached to an upper portion of each support part 13. Each drive mechanism 16 is configured to reciprocate (move up and down) the upper table 11 relative to the lower table 12 along the height direction. Providing such a configuration enables the upper tool U attached to the upper tool holders 14 of the upper table 11 and the lower tool L attached to the lower tool holder 15 of the lower table 12 to move relative to each other.

[0036] It is also possible to use another driving means such as a servomotor instead of the hydraulic cylinder for each drive mechanism 16. In addition, the drive mechanism 16 is not limited to the embodiment described above, and the lower table 12 may be driven instead of the upper table 11.

[0037] A position detection sensor detects the movement position of the upper tool U relative to the lower tool L when the upper table 11 is moved by the drive mechanism 16, for example. This position detection sensor is formed by, for example, an encoder or a linear scale, and is well-known, and thus detailed description thereof will be omitted.

[0038] The back gauge 17 is provided behind the upper tool U and the lower tool L in the depth direction to be movable, as illustrated in Figure 1, and is configured to allow position adjustment in the left-right direction in accordance with the position of the bending of the workpiece W in the longitudinal direction (X-axis direction) of the upper tool U and the lower tool L and the width dimension of the workpiece W in the left-right direction. In addition, the back gauge 17 is configured to allow position adjustment in the depth direction and height direction to be able to correspond to the depth and height of the abutment position for each workpiece W. The position adjustment of the back gauge 17 in each direction is performed by appropriately controlling a moving mechanism such as a servomotor.

[0039] In addition, in the back gauge 17, a configuration is also known in which a sensor (not illustrated) that detects that the abutment portion of the workpiece W has come into contact with the back gauge 17, for example, a potentiometer, is provided. Furthermore, as the control of the back gauge 17, after positioning the workpiece W in the front-rear direction, the back gauge 17 is slightly moved backward to avoid interference with the workpiece W during the bending of the workpiece W. Note that the back gauge 17 can employ various known configurations, and thus detailed description thereof will be omitted.

[0040] The angle detection sensor 18, as illustrated in Figures 1 and 4, is attached, for example, to a facing surface 12a of the lower table 12 that faces the workpiece supply robot 100, and is configured to be movable in the longitudinal direction of the upper tool U and the lower tool L. Specifically, an angle detection sensor moving part 19 is provided on the facing surface 12a of the lower table 12, and the angle detection sensor 18 is attached on the angle detection sensor moving part 19.

[0041] The angle detection sensor moving part 19 is a so-called linear motion mechanism that includes a rail part 19a laid on the facing surface 12a of the lower table 12, a base table (not illustrated) that is movable on and along the rail part 19a, and base table driving means (not illustrated) that drives the base table. The angle detection sensor moving part 19 is configured such that the base table moves on the rail part 19a based on a control signal from an angle detection sensor control unit 250, which will be described later, of the control device 200. Note that the angle detection sensor moving part 19 can employ various known configurations, and thus detailed description thereof will be omitted.

[0042] The angle detection sensor 18 is attached to the base table of the angle detection sensor moving part 19, and is configured to move in the longitudinal direction of the upper tool U and the lower tool L by driving the base table with the base table driving means. The angle detection sensor 18 includes, for example, a first sensor (not illustrated) located proximate the position of the bending by the upper tool U and the lower tool L, and a second sensor (not illustrated) arranged to be spaced forward in the depth direction by a predetermined distance from the first sensor.

[0043] The first sensor and the second sensor are used to detect the outer angles of the front and rear surfaces with respect to the bending line of the workpiece W. For example, non-contact sensors using laser beams and cameras or contact sensors using potentiometers or the like can be employed. The first sensor and the second sensor are provided at the same height. The angle detection sensor 18 is configured to enable calculation of the bending angle of the workpiece W based on the line segment of the lower tool L and the line segment of the workpiece W by tilting the camera with respect to the laser beam and picking up an image with the first and second sensors, for example, when performing bending of the workpiece W.

[0044] The height detection sensor 20 is configured to able to detect the position of the workpiece W in the height direction, which is inserted between the upper tool U and the lower tool L, and, for example, is configured to detect the distance to the workpiece W in the height direction. As the height detection sensor 20, for example, a laser range finder using a laser beam or a potentiometer can be employed. Note that the height detection sensor 20 is not limited to the above-described configuration, and may have any configuration that can detect that the position of the workpiece W in the height direction is within a predetermined range.

[0045] For example, the height detection sensor 20 may be configured to detect that the position of the workpiece W in the height direction is within a predetermined range by detecting contact with the surface of the workpiece W. Note that, in this specification, "contact with the surface of workpiece W" includes not only the case of complete contact with the surface of the workpiece W, but also the case where it is close enough to be evaluated as being in contact with the surface of workpiece W.

[0046] Specifically, the height detection sensor is a reflective photoelectric sensor, where the light emitted from the light-emitting element of the photoelectric sensor is reflected by the surface of the workpiece W, and the reflected light may be received by the light-receiving element of the photoelectric sensor, thereby detecting that the position of the workpiece W in the height direction is within a predetermined range.

[0047] In addition, the height detection sensor 20 may detect that the position of the workpiece W in the height direction is within a predetermined range by a magnetic force, or may detect that the position of the workpiece W in the height direction is within a predetermined range by the expansion and contraction of a surface detection rod or the like including an expansion and contraction part. Furthermore, the height detection sensor 20 may also be a photo reflector, a proximity sensor, an ultrasonic sensor, an eddy current sensor, or a contact-type sensor such as a force sensor.

[0048] The height detection sensor 20 is arranged on the workpiece supply robot 100 side (forward in the depth direction) rather than the upper tool U and the lower tool L, as illustrated in Figures 1 and 4. The height detection sensor 20 is, for example, attached to the facing surface 12a of the lower table 12 facing the workpiece supply robot 100, and is configured to be movable in the longitudinal direction of the upper tool U and the lower tool L. Specifically, a height detection sensor moving part 40 is provided on the facing surface 12a of the lower table 12, and the height detection sensor 20 is attached on the height detection sensor moving part 40.

[0049] The height detection sensor 20 is attached to a base table, which will be described later, of the height detection sensor moving part 40, and is configured to move in the longitudinal direction of the upper tool U and the lower tool L. The height detection sensor moving part 40 is a so-called linear motion mechanism that includes a base table (not illustrated) that can move on and along the rail part 19a of the angle detection sensor moving part 19, as illustrated in Figures 4 and 10. The height detection sensor moving part 40 is configured such that the base table moves on the rail part 19a by the base table driving means of the angle detection sensor moving part 19.

[0050] The height detection sensor moving part 40 having such a configuration is configured to move the height detection sensor 20 in the longitudinal direction of the upper tool U and the lower tool L. Specifically, the base table of the height detection sensor moving part 40 includes a connection part (not illustrated) that can be connected with and disconnected from the angle detection sensor moving part 19, and by connecting the height detection sensor moving part 40 with the angle detection sensor moving part 19, the base table moves on the rail part 40a, moving the height detection sensor 20 to a predetermined position. The mechanical configuration itself of the height detection sensor moving part 40 can employ various known configurations, and thus detailed description thereof will be omitted.

[0051] The angle detection sensor 18 and the height detection sensor 20, which have the above-described configuration, are configured, for example, such that the height detection sensor 20 can move from one end of the rail part 19a to the detection position together with the angle detection sensor 18, and only the angle detection sensor 18 can be retracted to one end or the other end of the rail part 19a. In addition, the angle detection sensor 18 and the height detection sensor 20 are configured such that, after detecting the position of the workpiece W in the height direction, the angle detection sensor 18 can move to the detection position of the height detection sensor 20, and then the height detection sensor 20 can be retracted to one end of the rail part 19a together with the angle detection sensor 18.

[0052] Note that the height detection sensor moving part 40 is not limited to the configuration described above. For example, the height detection sensor moving part 40 may further include the base table driving means (not illustrated) that drives the base table of the height detection sensor moving part 40, and each of the height detection sensor 20 and the angle detection sensor 18 may be configured to be independently movable in the longitudinal direction of the upper tool U and the lower tool L.

[0053] By providing such a configuration, the angle detection sensor 18 and the height detection sensor 20 are configured such that, for example, the height detection sensor 20 can move from one end of the rail part 19a to the detection position and be retracted to one end of the rail part 19a after detecting the position of the workpiece W in the height direction. In addition, the angle detection sensor 18 and the height detection sensor 20 are configured such that, after that, the angle detection sensor 18 can move from the other end of the rail part 19a to the detection position, and can be retracted to the other end of the rail part 19a after detecting the bending angle of the workpiece W.

[0054] In addition, when the height detection sensor moving part 40 is provided with the base table driving means, the height detection sensor moving part 40 further includes a rail part (not illustrated) laid on the facing surface 12a of the lower table 12 facing the workpiece supply robot 100, separate from the rail part 19a of the angle detection sensor moving part 19, and the base table of the height detection sensor moving part 40 may move on the rail part of the height detection sensor moving part 40.[Configuration of Control Device]

[0055] Figure 5 is a functional block diagram illustrating a control device in the present embodiment.

[0056] The control device 200 includes an input unit 210, a display unit 220, a robot control unit 230, a height detection sensor control unit 240, an angle detection sensor control unit 250, and a storage unit 260, as illustrated in Figure 5. The control device 200 is connected to the press brake 10 and the workpiece supply robot 100 by various known configurations.

[0057] The input unit 210 includes input devices such as a keyboard, a mouse, a press button switch, a tact switch, and a key lock switch. By operating the input unit 210, in addition to the information input function normally required in the bending system 1, it is possible to perform operations such as selecting the numerical control (NC) control program, which will be described later, in the storage unit 260, for example.

[0058] The display unit 220 includes a display as a display device, and in addition to the screen display functions normally required in the bending system 1, the display unit 220 displays, for example, a selection screen for selecting an NC control program. Furthermore, the display unit 220 can be comprised of a touch panel having a function of the input unit 210. When the display unit 220 is comprised of a touch panel, a user can input, to the control device 200, various types of information about selection of the NC control program or the like, by operating the display unit 220, for example.

[0059] Note that the configurations of the input unit 210 and the display unit 220 are not limited to the configurations described above, and they may be any configurations having similar functions (for example, display means, input means, and the like that can be used from a remote place) instead of the input unit 210 and the display unit 220.

[0060] The robot control unit 230 is configured to enable computerized numerical control (CNC) control of the workpiece supply robot 100. Specifically, the robot control unit 230 is configured to control the arm part 140 and the moving mechanism 160 so that the robotic hand 120 reaches the uppermost workpiece W among the plurality of workpieces W stacked on the workpiece mounting table P, based on the NC control program for robots, which will be described later, stored in the storage unit 260 when transferring (supplying) the workpiece W from the workpiece mounting table P.

[0061] In addition, the robot control unit 230 is configured to control the robotic hand 120 to grip the workpiece W with the hand main body 122 when the robotic hand 120 reaches the workpiece W, or to control the air suction source to hold the workpiece W with the suction parts 124, and to control the arm part 140 and the moving mechanism 160 to insert the held workpiece W between the upper tool U and the lower tool L of the press brake 10.

[0062] Furthermore, the robot control unit 230 is configured to control the arm part 140 and the moving mechanism 160 so that the workpiece W held by the robotic hand 120 falls within the allowable range when the position of the workpiece W in the height direction detected by the height detection sensor 20 does not fall within the allowable range. Furthermore, the robot control unit 230 controls the workpiece supply robot 100 so that the workpiece supply robot 100 performs a following operation that assists in bending during the bending by the press brake 10.

[0063] The height detection sensor control unit 240 includes a height determination processing unit 242, a holding position specifying unit 244, and a movement control unit 246. The height determination processing unit 242 is configured to determine whether or not the position of the workpiece W in the height direction detected by the height detection sensor 20 falls within the allowable range.

[0064] Specifically, the height determination processing unit 242 acquires a value detected by the height detection sensor 20 from the height detection sensor 20 and determines whether the value falls within a predetermined allowable range. The allowable range is determined, for example, when the height detection sensor 20 detects the distance to the workpiece W in the height direction, by performing calibration based on the vertical distance from the height detection sensor 20 to the XY plane including the distal end of the lower tool L of the press brake 10, and by using the allowable error in the height direction from that distance.

[0065] In addition, the height determination processing unit 242 is configured to adjust the position of the workpiece W by the robot control unit 230 when the position of the workpiece W in the height direction detected by the height detection sensor 20 does not fall within the allowable range.

[0066] The holding position specifying unit 244 is configured to be able to specify the position of the workpiece supply robot 100 that holds the workpiece W. For example, the holding position specifying unit 244 specifies the position (holding position) of the workpiece supply robot 100 that holds the workpiece W from the NC control program for robots of the storage unit 260. In addition, the holding position specifying unit 244 may acquire the coordinate information of the workpiece supply robot 100 and specify the position of the workpiece supply robot 100 from the acquired coordinate information and the information of the robotic hand 120 being used.

[0067] Furthermore, when the bending system 1 further includes a holding position specifying sensor, the holding position specifying unit 244 may specify the position of the workpiece supply robot 100 based on the detection result of the holding position specifying sensor. Furthermore, when the bending system 1 further includes a camera, the holding position specifying unit 244 may specify the position of the workpiece supply robot 100 from the video or image of the camera.

[0068] In addition, the holding position specifying unit 244 may scan the position of the workpiece W in the height direction by moving the height detection sensor 20 in the X-axis direction from one end to the other end of the workpiece, and specify the location where the position in the height direction is the highest, that is, the location where the deflection of the workpiece W is minimal, as the position of the workpiece supply robot 100 that holds the workpiece W.

[0069] The movement control unit 246 is configured to move the height detection sensor 20 to the vicinity of the position of the workpiece supply robot 100. Specifically, the movement control unit 246 controls the angle detection sensor moving part 19 and the height detection sensor moving part 40, thereby moving the height detection sensor 20, which is attached to the base table of the height detection sensor moving part 40, to the vicinity of the position of the workpiece supply robot 100 specified by the holding position specifying unit 244. Here, "the vicinity of the position of the workpiece supply robot 100 (workpiece holding means)" refers to the positional area closest to the position among positions where the detection of the workpiece W is not affected, a detection range 22 does not interfere with the workpiece supply robot 100, and no obstructions such as holes or irregularities provided in the workpiece W are present within the detection range 22, even if the detection position of the height detection sensor 20 changes due to the position error of the workpiece supply robot 100 or the gripping position error of the workpiece W.

[0070] In addition, if obstacles such as holes or irregularities in the workpiece W, which may hinder detection, are present within the detection range 22 of the height detection sensor 20, the movement control unit 246 is configured to control the angle detection sensor moving part 19 and the height detection sensor moving part 40 so that the obstacles do not enter the detection range 22. Furthermore, the movement control unit 246 is configured to control the angle detection sensor moving part 19 and the height detection sensor moving part 40 so that the workpiece supply robot 100 falls out of the detection range 22 of the height detection sensor 20 when the detection range 22 of the height detection sensor 20 and the robotic hand 120 of the workpiece supply robot 100 overlap with each other, or when the height detection sensor 20 and the robotic hand 120 interfere with each other.

[0071] Figure 6 is a diagram illustrating an example of a positional relationship between the height detection sensor and the robotic hand in the present embodiment.

[0072] First, with reference to Figure 6, the detection position of the height detection sensor 20 will be described in the case where the robotic hand 120 of the workpiece supply robot 100 includes a hand main body 122 that grips the workpiece W. For example, as illustrated in Figure 6(a), when the robotic hand 120 and the detection range 22 of the height detection sensor 20 do not overlap with each other, the movement control unit 246 controls the angle detection sensor moving part 19 and the height detection sensor moving part 40 so that the center of the detection range 22 is located on an extension line CL of the center of the holding position of the workpiece W with the robotic hand 120.

[0073] On the other hand, depending on the holding position with the robotic hand 120, the detection range 22 and the holding position of the workpiece W may overlap with each other when the center of the detection range 22 of the height detection sensor 20 is located on the extension line CL of the center of the holding position of the workpiece W with the robotic hand 120. In this case, the position of the height detection sensor 20 is moved in the X-axis direction so that the amount of movement from the extension line CL is minimized within the range where the detection range 22 does not deviate from the workpiece W. For example, the movement control unit 246 controls the angle detection sensor moving part 19 and the height detection sensor moving part 40 so that the center of the detection range 22 of the height detection sensor 20 is located at a position moved by x 1 in the X-axis direction from a position on the extension line CL, as illustrated in Figures 6(b) and 6(c).

[0074] Figures 7 to 9 each are a diagram illustrating an example of the positional relationship between the height detection sensor and the robotic hand in the present embodiment.

[0075] Next, with reference to Figures 7 to 9, the detection position of the height detection sensor 20 will be described in the case where the robotic hand 120 of the workpiece supply robot 100 includes the hand main body 122' and the plurality of suction parts 124. Note that Figures 7(a), 8(a), and 9(a) each illustrate the case where the suction parts 124 hold the upper surface (front surface) of the workpiece W, while Figures 7(b), 8(b), and 9(b) each illustrate the case where the suction parts 124 hold the lower surface (back surface) of the workpiece W.

[0076] For example, as illustrated in Figures 7(a) and 7(b), when the robotic hand 120 and the detection range 22 of the height detection sensor 20 do not overlap with each other, the movement control unit 246 controls the height detection sensor moving part 40 so that the center of the detection range 22 is located on the extension line CL' of the attachment part 122a, that is located at the center of the holding position of the workpiece W with the robotic hand 120, that is, the center of the hand main body 122'.

[0077] In addition, depending on the holding position with the robotic hand 120, the detection range 22 and the holding position of the workpiece W may overlap with each other when the center of the detection range 22 of the height detection sensor 20 is located on the extension line CL' of the center of the holding position of the workpiece W with the robotic hand 120.

[0078] However, as illustrated in Figures 8(a) and 9(a), in the case where the suction parts 124 of the robotic hand 120 hold the upper surface of the workpiece W, the robotic hand 120 does not hinder the detection of the height detection sensor 20, nor does the robotic hand 120 interfere with the height detection sensor 20 even if the detection range 22 of the height detection sensor 20 and the holding position of the workpiece W overlap with each other. Therefore, the movement control unit 246 controls the angle detection sensor moving part 19 and the height detection sensor moving part 40 so that the center of the detection range 22 is located on the extension line CL' of the center of the holding position of the workpiece W with the robotic hand 120.

[0079] On the other hand, in the case where the suction parts 124 of the robotic hand 120 hold the lower surface of the workpiece W, the robotic hand 120 may hinder the detection of the height detection sensor 20, or the robotic hand 120 and the height detection sensor 20 may interfere with each other when the height detection sensor 20 is located on the extension line CL'. In this case, the position of the height detection sensor 20 is moved in the X-axis direction so that the amount of movement from the extension line CL' is minimized within the range where the detection range 22 does not deviate from the workpiece W. For example, the movement control unit 246 controls the angle detection sensor moving part 19 and the height detection sensor moving part 40 so that the center of the detection range 22 of the height detection sensor 20 is located at a position moved by x 2 , x 3 in the X-axis direction from the position on the extension line CL' as illustrated in Figures 8(b) and 9(b).

[0080] The robot control unit 230 and the height detection sensor control unit 240, which have the above-described configuration, are configured to be able to execute a sensor movement control program 262 and a bending program 264, which will be described later, in the storage unit 260. In addition, the robot control unit 230 and the height detection sensor control unit 240 can execute the sensor movement control program 262 and the bending program 264 either consecutively or in parallel.

[0081] The angle detection sensor control unit 250 is configured to move the angle detection sensor 18, which is attached to the base table of the angle detection sensor moving part 19, to a predetermined position by controlling the angle detection sensor moving part 19. In addition, the angle detection sensor control unit 250 is configured to determine whether or not the angle detected by the angle detection sensor 18 falls within the allowable range when performing the bending of the workpiece W. Note that the angle detection sensor control unit 250 can employ various known configurations, and thus detailed description thereof will be omitted.

[0082] The storage unit 260 includes an NC control program for robots (not illustrated) for causing the workpiece supply robot 100 to execute the supply (insertion) of the workpiece W from the workpiece mounting table P to the press brake 10, the assistance in the bending of the workpiece W, and the transfer (carrying-out) of the workpiece W after the bending. In addition, the storage unit 260 has an NC control program for press brakes (not illustrated) for causing the press brake 10 to execute a predetermined bending process. Furthermore, the storage unit 260 includes the sensor movement control program 262 and the bending program 264.

[0083] The sensor movement control program 262 causes the control device 200 to execute a holding position specifying process of specifying the position of the workpiece supply robot 100 that holds the workpiece W, a height detection sensor movement process of moving the height detection sensor 20 to the vicinity of the position of the workpiece supply robot 100 specified by the holding position specifying process, a height detection process of detecting the position of the workpiece W in the height direction, and a height determination process of determining whether or not the position of the workpiece W in the height direction detected by the height detection sensor 20 falls within the allowable range.

[0084] The bending program 264 causes the control device 200 to execute a workpiece insertion process of causing the workpiece supply robot 100 to insert the workpiece W between the upper tool U and the lower tool L of the press brake 10, a workpiece position adjustment process of operating the workpiece supply robot 100 to adjust the position of the workpiece W if the position of the workpiece W in the height direction detected by the height detection sensor 20 in the height determination process of the sensor movement control program 262 does not fall within the allowable range, and bending processing of performing the bending of the workpiece W.

[0085] In the present embodiment, the sensor movement control program 262 and the bending program 264 have been described as different programs, but are not limited thereto, and may be a single program. In the present embodiment, the sensor movement control program 262 has been described as causing the control device 200 to execute the holding position specifying process, but the present invention is not limited thereto. For example, the bending system 1 may further include a design support device (not illustrated) that creates an NC control program for robots and an NC control program for press brakes. In this case, the design support device executes a holding position specifying process of specifying the holding position of the workpiece W with the workpiece supply robot 100 from the NC control program for robots, and the sensor movement control program 262 incorporates the specification result (position information) of the design support device. Also, when such a configuration is provided, the control unit 200 may not include the holding position specifying unit 244.

[0086] Figures 10 to 13 each are a schematic diagram illustrating an example of the operation of the bending system in the present embodiment.

[0087] An example of the operation of the bending system 1 which has the above-described configuration will be described with reference to Figures 10 to 13. First, as illustrated in Figures 10 and 11, in the bending system 1, the workpiece W is inserted between the upper tool U and the lower tool L of the press brake 10 by the workpiece supply robot 100. Next, in the state illustrated in Figure 11, the position of the workpiece W in the height direction is detected by the height detection sensor 20. Then, as illustrated in Figure 12, the workpiece supply robot 100 adjusts the position of the workpiece W in the height direction so that the position of the workpiece W in the height direction falls within the allowable range. After that, as illustrated in Figure 13, the workpiece supply robot 100 adjusts the position of the workpiece W in the depth direction by abutting the abutment portion of the workpiece W against the back gauge 17.

[0088] In the present embodiment, the bending system 1 preferably adjusts the position of the workpiece W in the height direction to avoid interference between the workpiece W and the angle detection sensor 18 and between the workpiece W and the height detection sensor 20, temporarily retracts the workpiece W before adjusting the position of the workpiece W in the depth direction, moves the angle detection sensor 18 and the height detection sensor 20, and subsequently returns the workpiece W to the position after the height adjustment. However, the present invention is not limited thereto. Alternatively, the bending system 1 may adjust the position of the workpiece W in the height direction after adjusting the position of the workpiece W in the depth direction. Alternatively, the bending system 1 may adjust the position of the workpiece W in the height direction and the position of the workpiece W in the depth direction simultaneously.[Sensor Movement Control Method According to the Present Embodiment]

[0089] Next, a sensor movement control method by the bending system 1 according to the present embodiment will be described. The sensor movement control method according to the present embodiment schematically includes a height detection sensor moving step of moving the height detection sensor 20 to the vicinity of the position of the workpiece supply robot 100 that holds the workpiece W, a height detection step of detecting the position of the workpiece W in the height direction, and a height determination step of determining whether or not the position of the workpiece W in the height direction detected by the height detection sensor 20 falls within the allowable range.

[0090] Figure 14 is a flowchart illustrating an example of the sensor movement control method in the present embodiment.

[0091] The sensor movement control method according to the present embodiment will be described in detail with reference to Figure 14. First, the bending system 1 specifies the position of the workpiece supply robot 100 that holds the workpiece W by the holding position specifying unit 244 of the height detection sensor control unit 240 of the control device 200 (S10 in Figure 14: holding position specifying step). Subsequently, the movement control unit 246 of the height detection sensor control unit 240 controls the angle detection sensor moving part 19 and the height detection sensor moving part 40 based on the position information specified by the holding position specifying unit 244, and moves the height detection sensor 20 to the vicinity of the holding position of the workpiece supply robot 100 (S20 in Figure 14: height detection sensor moving step).

[0092] After that, the height detection sensor 20 detects the position of the workpiece W in the height direction (S30 in Figure 14: height detection step). The height detection sensor 20 may detect the position of the workpiece W in the height direction at only one location, or may move from one detection location to detect the position of the workpiece W in the height direction at a plurality of locations.

[0093] Then, the height determination processing unit 242 of the height detection sensor control unit 240 of the control device 200 acquires a value of the workpiece W in the height direction detected by the height detection sensor 20, and determines whether or not the acquired position of the workpiece W in the height direction falls within the allowable range (S40 in Figure 14: height determination step). The height determination processing unit 242 causes the robot control unit 230 to adjust the position of the workpiece W if the position of the workpiece W in the height direction does not fall within the allowable range (NO in S40 in Figure 14) (S50 in Figure 14). Note that it is preferable to adjust the position of the workpiece W in the height direction by moving the workpiece W in the negative direction of the Z-axis to prevent errors due to backlash, but the present invention is not limited thereto.

[0094] If the position of the workpiece W in the height direction falls within the allowable range (YES in S40 in Figure 14), or if the position of the workpiece W in the height direction falls within the allowable range after the adjustment, the movement control unit 246 of the height detection sensor control unit 240 of the control device 200 controls the height detection sensor moving part 40 to move the height detection sensor 20 to a predetermined standby position (S60 in Figure 14: sensor moving step). Through the above-described steps, a series of the sensor movement control methods by the bending system 1 according to the present embodiment is executed.[Bending Method According to the Present Embodiment]

[0095] Next, the bending method using the bending system 1 according to the present embodiment will be described. The bending method according to the present embodiment schematically includes a workpiece insertion step of inserting, by the workpiece supply robot 100, the workpiece W between the upper tool U and the lower tool L of the press brake 10, a workpiece position adjusting step of operating the workpiece supply robot 100 to adjust the position of the workpiece W if the position of the workpiece W in the height direction detected by the height detection sensor 20 in the height determination step of the sensor movement control method does not fall within the allowable range, and a bending step of performing bending of the workpiece W.

[0096] Figure 15 is a flowchart illustrating an example of the bending method in the present embodiment.

[0097] The bending method according to the present embodiment will be described in detail with reference to Figure 15. First, in the bending system 1, the workpiece supply robot 100 holds the workpiece W on the workpiece mounting table P and supplies it to the press brake 10. Specifically, the workpiece supply robot 100 inserts the workpiece W held between the upper tool U and the lower tool L of the press brake 10 (S100 in Figure 15: workpiece insertion step).

[0098] Subsequently, the workpiece supply robot 100 adjusts the position of the workpiece W in the height direction. Specifically, if the position of the workpiece W in the height direction detected by the height detection sensor 20 in the height determination step in the sensor movement control method does not fall within the allowable range, the workpiece supply robot 100 moves the inserted workpiece W upward or downward in the Z-axis direction (S110 in Figure 15: workpiece position adjusting step). If the position of the workpiece W in the height direction falls within the allowable range, the workpiece supply robot 100 maintains its current height.

[0099] Simultaneously with or after the height adjustment, the workpiece supply robot 100 adjusts the position of the workpiece W in the depth direction and the longitudinal direction of the upper tool U and the lower tool L by abutting the abutment portion of the workpiece W against the back gauge 17 (S120 in Figure 15). After the position adjustment of the workpiece W is completed, the press brake 10 brings the upper tool U closer to the lower tool L, sandwiching the workpiece W between the upper tool U and the lower tool L. Then, the press brake 10 further brings the upper tool U closer to the lower tool L, while the workpiece supply robot 100 executes a following operation, and the bending is performed (S130 in Figure 15: bending step).

[0100] Also, during the bending step, the angle detection sensor control unit 250 of the control device 200 moves the angle detection sensor 18 to a predetermined position to detect the bending angle of the workpiece W. Then, the angle detection sensor control unit 250 determines whether or not the angle detected by the angle detection sensor 18 falls within the allowable range.

[0101] After that, the upper tool U of the press brake 10 is separated from the lower tool L, and the workpiece supply robot 100 transfers the bent workpiece W held to a predetermined position. Through the above-described steps, a series of bending methods by the bending system 1 according to the present embodiment is executed.

[0102] When performing the bending method according to the present embodiment continuously, only the first trial operation (check operation) involves height adjustment, depth adjustment, and width adjustment (adjustment in the longitudinal direction of the upper tool U and the lower tool L). The height information, depth information, and width information during the trial operation can be stored (learned) in the workpiece supply robot 100 and control device 200, allowing for the omission of adjustments from the second time onward, or height adjustment, depth adjustment, and width adjustment can be performed each time.

[0103] In the present embodiment, the sensor movement control method and the bending method have been described separately, but the present invention is not limited thereto, and the sensor movement control method may be executed as part of the bending method.[Advantages of Press Brake, Bending System, and Sensor Movement Control Method According to the Present Embodiment]

[0104] As described above, the press brake 10 according to the present embodiment includes the upper tool U and the lower tool L that are movable relative to each other, the height detection sensor 20 that can detect the position of the workpiece W in the height direction, which is inserted between the upper tool U and the lower tool L, the height detection sensor moving part 40 that moves the height detection sensor 20 in a longitudinal direction of the upper tool U and the lower tool L, and the control unit (height detection sensor control unit 240). The control unit (height detection sensor control unit 240) includes the movement control unit 246 that moves the height detection sensor 20 to a vicinity of the position of workpiece holding means (workpiece supply robot 100) that holds the workpiece W, and the height determination processing unit 242 that determines whether or not the position of the workpiece W in the height direction detected by the height detection sensor 20 falls within an allowable range.

[0105] The press brake 10 according to the present embodiment has such a configuration, whereby the height detection sensor 20 detects the position of the workpiece W in the height direction, and the height determination processing unit 242 determines whether or not the position of the workpiece W in the height direction detected by the height detection sensor 20 falls within the allowable range. Therefore, there is an advantage that the positioning of the workpiece W in the height direction can be performed without conducting a visually check in the vicinity of the workpiece W to be subjected to the bending. In particular, according to the sensor movement control device in the present embodiment, it is possible to automatically perform positioning of the workpiece W in the height direction, thereby capable of achieving the high operation efficiency of the press brake and reducing the skill requirements for operators.

[0106] In addition, since the height detection sensor 20 can move to the vicinity of the position of the workpiece holding means (workpiece supply robot 100) to detect the position of the workpiece W in the height direction, it has the advantage of being less affected by the deflection of the workpiece W when detecting the position of the workpiece W in the height direction. Since the workpiece W deflects as farther from the holding position of the workpiece W with the workpiece holding means (workpiece supply robot 100), for example, even if the greatly deflected location of the workpiece W reaches the height of the distal end of the lower tool L when the workpiece is arranged at the distal end of the lower tool L, the location with less deflection is located above the height of the distal end of the lower tool L, and the position of the workpiece W in the height direction may not fall within the allowable range. In the sensor movement control device according to the present embodiment, it is possible to detect the position of the workpiece W in the height direction by moving to the vicinity of a location with little deflection, that is, the position of the workpiece holding means (workpiece supply robot 100), allowing for more accurate positioning of the workpiece W in the height direction.

[0107] Furthermore, the press brake 10 according to the present embodiment includes the lower table 12 to which a lower tool U is attached, and the height detection sensor 20 is movably attached to the facing surface 12a of the lower table 12 facing the workpiece holding means (workpiece supply robot 100). By providing such a configuration, there is an advantage of being able to determine more accurately whether the position of the workpiece W in the height direction falls within the allowable range. For example, in the case where the height detection sensor 20 detects the position of the workpiece W in the height direction behind the upper tool U and the lower tool L in the depth direction, the position of the workpiece W in the height direction may be determined to fall within the allowable range as long as the position of the distal end (abutment portion) of the workpiece W in the height direction falls within the allowable range even if the position of the workpiece W at the location where the workpiece W is sandwiched between the upper tool U and the lower tool L, that is, the location where the workpiece W is bent does not fall within the allowable range. In the sensor movement control device according to the present embodiment, the height detection sensor 20 is arranged on the workpiece holding means (workpiece supply robot 100) side rather than the upper tool U and the lower tool L, thereby capable of preventing such erroneous determination. In addition, the height detection sensor 20 has the advantage of being able to detect the position of the workpiece W in the height direction at a position closer to the workpiece holding means (workpiece supply robot 100). Furthermore, it has the advantage of capable of reducing manufacturing costs and preventing the enlargement of the press brake 10 by attaching the height detection sensor 20 to the lower table 12.

[0108] Furthermore, in the press brake 10 according to the present embodiment, the control unit (height detection sensor control unit 240) is configured to control the height detection sensor moving part 40 so that the workpiece holding means (workpiece supply robot 100) falls out of the detection range of the height detection sensor 20. By providing such a configuration, when the workpiece holding means (workpiece supply robot 100) enters the detection range of the height detection sensor 20, it is possible to prevent the workpiece holding means (workpiece supply robot 100) from being erroneously detected as the workpiece W, and it has the advantage of being able to detect the position of the workpiece W in the height direction more accurately. In addition, according to such a sensor movement control device according to the present embodiment, it is also possible to prevent physical interference between the workpiece holding means (workpiece supply robot 100) and the height detection sensor 20.

[0109] In addition, the press brake 10 according to the present embodiment includes the angle detection sensor 18 that can detect the bending angle of the workpiece W during the bending of the workpiece W. The angle detection sensor 18 is configured to be movable in the longitudinal direction of the upper tool U and the lower tool L, and each of the height detection sensor 20 and the angle detection sensor 18 is configured to be independently movable in the longitudinal direction of the upper tool U and the lower tool L. By providing such a configuration, there is an advantage in that interference between the workpiece holding means (workpiece supply robot 100) or the workpiece W and the angle detection sensor 18 can be prevented, and the height detection sensor 20 can sufficiently approach the vicinity of the position of the workpiece holding means (workpiece supply robot 100).[Modified Examples]

[0110] Although the preferred embodiment of the present invention has been described above, the technical scope of the present invention is not limited to the scopes described in the above-described embodiment. Various modifications or improvements can be added to the embodiment described above.

[0111] For example, the above-described embodiment has been described in which the press brake 10 includes a lower table 12 to which the lower tool L is attached, and the height detection sensor 20 is movably attached to the facing surface 12a of the lower table 12 facing the workpiece holding means (workpiece supply robot 100), but the present invention is not limited thereto. For example, the height detection sensor 20 may be attached to a surface other than the facing surface 12a of the lower table 12 facing the workpiece holding means (workpiece supply robot 100), or may be attached to a location other than the lower table 12, such as the lower tool holder 15, the upper table 11, or the upper tool holder 14 of the press brake 10. Also, the height detection sensor 20 may be movably attached to the floor surface or ceiling surface of a factory or the like where the press brake 10 is used.

[0112] The above-described embodiment has been described in which the control unit (height detection sensor control unit 240) is configured to control the height detection sensor moving part 40 so that the workpiece holding means (workpiece supply robot 100) falls out of the detection range of the height detection sensor 20, but the present invention is not limited thereto. As long as it does not interfere with the operation of the workpiece holding means (workpiece supply robot 100), the workpiece holding means (workpiece supply robot 100) may enter the detection range of the height detection sensor 20.

[0113] The above-described embodiment has been described in which the press brake 10 includes the angle detection sensor 18 that can detect the bending angle of the workpiece W during the bending of the workpiece W, the angle detection sensor 18 is configured to be movable in the longitudinal direction of the upper tool U and the lower tool L, and each of the height detection sensor 20 and the angle detection sensor 18 are configured to be independently movable in the longitudinal direction of the upper tool U and the lower tool L, but the present invention is not limited thereto. The press brake 10 may not need to include the angle detection sensor 18 that can detect the bending angle of the workpiece W during the bending of the workpiece W. That is, the height detection sensor 20 may be used as the angle detection sensor 18, or may be configured not to perform angle detection. In addition, in the press brake 10, the height detection sensor 20 is attached to the angle detection sensor 18, for example, and the height detection sensor 20 and the angle detection sensor 18 may move together as one unit. When the height detection sensor 20 and the angle detection sensor 18 move together as one unit, the angle detection sensor moving part 19 and the height detection sensor moving part 40 can be combined into one, which can reduce manufacturing costs and prevent the enlargement of the press brake 10.

[0114] The above-described embodiment has been described in which the number of the height detection sensors 20 is one, but the present invention is not limited thereto, and a plurality of height detection sensors 20 may be present. When the plurality of height detection sensors 20 are installed, they may be configured to be independently movable. When a plurality of height detection sensors 20 are provided, the plurality of height detection sensors 20 may be provided in the longitudinal direction of the upper tool U and the lower tool L, or they may be provided in the front and rear (depth direction) of the upper tool U and the lower tool L. Also, both may be combined.

[0115] The above-described embodiment has been described in which the robotic hand 120 includes the hand main body 122 or the hand main body 122' and the suction parts 124, but the present invention is not limited thereto, and the robotic hand 120 may include the hand main body 120 and the suction parts 124, and it may be possible to selectively grip and hold, by suction, the workpiece W.

[0116] The above-described embodiment has been described in which the bending method includes adjusting the position of the workpiece W in the depth direction and width direction of the workpiece W simultaneously with or after height adjustment, but the present invention is not limited thereto, and the height adjustment may be performed after adjusting the position of the workpiece W in the depth direction and width direction.

[0117] The above-described embodiment has been described in which the angle detection sensor 18 is attached only to the facing surface 12a of the lower table 12 facing the workpiece supply robot 100, but the present invention is not limited thereto. The press brake 10 may further include an angle detection sensor 18 on the back side of the facing surface 12a of the lower table 12 that faces the workpiece supply robot 100.Reference Signs List

[0118] 1 Bending system 10 Press brake 11 Upper table 12 Lower table 13 Support part 14 Upper tool holder 15 Lower tool holder 16 Drive mechanism 17 Back gauge 18 Angle detection sensor 19 Angle detection sensor moving part 19a Rail part 20 Height detection sensor 22 Detection range 40 Height detection sensor moving part 100 Workpiece supply robot 120 Robotic hand 122, 122' Hand main body 124 Suction part 140 Arm part 160 Moving mechanism 160a Rail part 160b Base table 200 Control device 210 Input unit 220 Display unit 230 Robot control unit 240 Height detection sensor control unit 242 Height determination processing unit 244 Holding position specifying unit 246 Movement control unit 250 Angle detection sensor control unit 260 Storage unit 262 Sensor movement control program 264 Bending program L Lower tool P Workpiece mounting table U Upper tool W Workpiece

Claims

1. A press brake, comprising: an upper tool and a lower tool that are movable relative to each other; a height detection sensor configured to be able to detect a position of a workpiece in a height direction, the workpiece being inserted between the upper tool and the lower tool; a height detection sensor moving part configured to move the height detection sensor in a longitudinal direction of the upper tool and the lower tool; and a control unit, wherein the control unit includes: a movement control unit configured to move the height detection sensor to a vicinity of a position of workpiece holding means configured to hold the workpiece; and a height determination processing unit configured to determine whether or not the position of the workpiece in the height direction detected by the height detection sensor falls within an allowable range.

2. The press brake according to claim 1, further comprising a lower table to which the lower tool is attached, wherein the height detection sensor is movably attached to a facing surface of the lower table facing the workpiece holding means.

3. The press brake according to claim 1 or 2, wherein the control unit is configured to control the height detection sensor moving part so that the workpiece holding means falls out of a detection range of the height detection sensor.

4. The press brake according to claim 1 or 2, further comprising an angle detection sensor configured to be able to detect a bending angle of the workpiece during bending of the workpiece, wherein the angle detection sensor is configured to be movable in the longitudinal direction of the upper tool and the lower tool, and wherein each of the height detection sensor and the angle detection sensor is configured to be independently movable in the longitudinal direction of the upper tool and the lower tool.

5. A bending system, comprising: a press brake configured to carry out bending of a plate-shaped workpiece having a predetermined length; a workpiece supply robot configured to supply the workpiece to the press brake; a height detection sensor; a height detection sensor moving part; and a control device configured to control the press brake, the workpiece supply robot, the height detection sensor, and the height detection sensor moving part, wherein the press brake includes an upper tool and a lower tool that are movable relative to each other, wherein the workpiece supply robot is configured to insert the workpiece between the upper tool and the lower tool, wherein the height detection sensor is configured to be able to detect a position of the workpiece in a height direction, the workpiece being inserted between the upper tool and the lower tool, wherein the height detection sensor moving part is configured to move the height detection sensor in a longitudinal direction of the upper tool and the lower tool, and wherein the control device includes: a movement control unit configured to move the height detection sensor to a vicinity of a position of workpiece holding means configured to hold the workpiece; and a height determination processing unit configured to determine whether or not the position of the workpiece in the height direction detected by the height detection sensor falls within an allowable range.

6. A sensor movement control method, comprising: moving a height detection sensor to a vicinity of a position of workpiece holding means, the height detection sensor being configured to be able to detect a position of a workpiece in a height direction, the workpiece holding means being configured to hold the workpiece inserted between an upper tool and a lower tool that are movable relative to each other; detecting the position of the workpiece in the height direction; and determining whether or not the position of the workpiece in the height direction detected by the height detection sensor falls within an allowable range.

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