JP2013212516A - Overload protection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overload protection device which can reliably avoid an overload due to a cumulative load.SOLUTION: An overload protection device 1 includes: a load detection unit 2 for detecting the load of a press brake 10; a cumulative load calculating unit 3 for accumulating the load detected by the load detection unit 2 and calculating a cumulative load; an overload determining unit 4 for determining whether it is overloaded by comparing the cumulative load with a predetermined threshold; and an operating condition setting unit 5 for setting an operating condition with which an overload can be avoided, by changing an operating condition of the press brake 10 when the overload detection unit 4 determines that it is overloaded.

Description

  The present invention relates to an overload protection device for protecting a bending machine from an overload caused by a cumulative load in a bending machine such as a press brake.

  Conventionally, the table operation pattern of the press brake is roughly divided into five steps of approach, bending, pressurization, evacuation, and standby as one cycle, and the set speed to the lower limit position set in advance by the operator's start operation , And pressurizes for the time set by the lower limit holding timer, then rises and waits, and thereafter, the operation is repeatedly performed by the operator's starting operation.

  In the electric servo press brake, a servo motor having a maximum torque and a rated torque that meet the specifications is selected in advance so that the motor can be accelerated and decelerated at the maximum speed of the machine and kept pressurized for a certain time with the maximum capacity.

  Therefore, even if the acceleration / deceleration load and the pressurization load are under the maximum torque, depending on the conditions, the effective load for one cycle may exceed the rated torque. There was a load error. For example, in an operation where the stroke amount is extremely short, the high pressure pressurization holding time is long, and the standby time is short, an overload error due to the accumulated load may occur. However, if an overload error occurs during machining, the work must be interrupted, and power must be turned on again, so that time is lost and work efficiency decreases.

  Therefore, Patent Document 1 is disclosed as a control device for reducing such an overload error due to the accumulated load. In the bending machine control device disclosed in Patent Document 1, when the avoidance load set on the near side of the load for determining an overload error is exceeded, the servo motor is controlled in a direction in which the upper die is separated from the lower die. This prevents overload errors.

JP 2009-285704 A

However, in the above-described conventional bending machine control device, since the mold is only controlled in the direction to separate immediately before the overload error occurs, the overload error can be made difficult to occur, but it depends on the accumulated load. There is a problem that the overload itself cannot be avoided by setting or the like.

Therefore, the present invention has been proposed in view of the above-described circumstances, and an object thereof is to provide an overload protection device that can reliably avoid an overload due to a cumulative load.

  In order to solve the above-described problem, an overload protection device according to the present invention is an overload protection device that protects a bending machine from overload, and a load detection unit that detects a load of the bending machine; Cumulative load calculation means for calculating the cumulative load by accumulating the load detected by the load detection means, and overload determination means for comparing the cumulative load with a predetermined threshold value to determine whether or not the load is overload And an operation condition setting means for setting an operation condition that can avoid an overload by changing an operation condition of the bending machine when the overload determination means determines that the load is overloaded. And

  According to the overload protection device of the present invention, when it is determined that the load is overloaded, the operating condition of the bending machine can be changed to avoid the overload. It can be avoided reliably.

It is a figure for demonstrating the structure of the overload protection apparatus which concerns on one Embodiment to which this invention is applied. It is a flowchart for demonstrating the procedure of the overload protection process by the overload protection apparatus which concerns on one Embodiment to which this invention is applied. It is a figure for demonstrating operation | movement of 1 process by the overload protection apparatus which concerns on one Embodiment to which this invention is applied. It is a figure which shows an example of the selection screen of the protection function by the overload protection apparatus which concerns on one Embodiment to which this invention is applied. It is a figure which shows the present operating condition by the overload protection apparatus which concerns on one Embodiment to which this invention is applied. It is a figure which shows an example of the display screen of the recommended operation condition by the overload protection apparatus which concerns on one Embodiment to which this invention is applied. It is a figure which shows an example of the selection screen of the operating condition by the overload protection apparatus which concerns on one Embodiment to which this invention is applied. It is a figure which shows an example of the input screen of the operating condition by the overload protection apparatus which concerns on one Embodiment to which this invention is applied. It is a figure which shows an example of the input screen of the operating condition by the overload protection apparatus which concerns on one Embodiment to which this invention is applied.

  Hereinafter, an embodiment to which the present invention is applied will be described with reference to the drawings.

[Configuration of overload protection device]
FIG. 1 is a block diagram showing the configuration of the overload protection device according to this embodiment. As shown in FIG. 1, the overload protection device 1 according to the present embodiment includes a load detection unit 2 that detects the load of the press brake 10, and a cumulative load calculation unit that calculates the cumulative load by accumulating the detected loads. 3 and an overload determination unit 4 that determines whether or not the load is overloaded by comparing the accumulated load with a predetermined threshold, and when the overload determination unit 4 determines that the load is overloaded, An operation condition setting unit 5 is provided for setting an operation condition that can avoid an overload by changing the operation condition.

  An overload protection device 1 according to this embodiment is mounted on a control panel of a press brake 10 or an NC device that controls the press brake 10 that is a target of overload protection, and a servo amplifier 11 that drives a servo motor of the press brake 10. Are connected to a storage unit 12 for storing a machining program and a control program, and an operation unit 13 for inputting an operation by an operator of the press brake 10. The overload protection device 1 is constituted by a microcomputer including a ROM, a RAM, and an input / output interface, and each of the above-described units shows a functional configuration realized by the microcomputer.

  The load detection unit 2 detects a load acting on the servo motor from the servo amplifier 11 as a torque.

  Based on the servo motor torque, drive time, and section information detected by the load detection unit 2, the cumulative load calculation unit 3 performs, for example, the cumulative load of each section such as approach, bending, pressurization, evacuation, and standby and one process. The cumulative load for each step is calculated, and the cumulative load for several processes is further calculated.

  The overload determination unit 4 compares the cumulative load calculated by the cumulative load calculation unit 3 with a preset threshold value, and determines that the load is an overload when the cumulative load exceeds the threshold value. The overload determination unit 4 also determines whether or not the number of times determined as overload exceeds the specified number.

  The operating condition setting unit 5 calculates the load for each section and the load for one process based on the operating conditions such as the moving distance, speed, pressurization holding time, standby time, etc. of the mold so that overload can be avoided. The operating conditions are changed and set. Further, the operation condition setting unit 5 causes the operator of the press brake 10 to select an operation condition to be set, and when the value of the selected operation condition is set by the operator, an operation condition other than the set operation condition is set. Set the operating conditions that can avoid overload by changing.

  The storage unit 12 stores a program and data for executing an overload protection process described below in addition to a normal control program for controlling the press brake 10 and a machining program for performing bending. ing. As data for executing the overload protection process, for example, section information recording the moving speed, moving distance, time, load, etc. of the mold of each section is stored, and the servo motor that drives the press brake 10 is stored. The rated output, rated torque, maximum torque, rated rotational speed, maximum rotational speed, etc. are also stored.

  The operation unit 13 includes a switch, a touch panel, and the like that receive an input from an operator who operates the press brake 10, and displays a message, a driving state, and the like on the touch panel. Further, when executing the overload protection process, an operation condition setting screen is displayed so that the operator can manually set the operation condition.

  In this embodiment, a press brake is illustrated as an example of a bending machine, but the overload protection device according to this embodiment is mounted on any other apparatus as long as it is a bending machine. It is possible.

[Procedure for overload protection processing]
Next, overload protection processing by the overload protection device 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is a flowchart for explaining the procedure of the overload protection process according to this embodiment.

  As shown in FIG. 2, first, in step S101, the load detection unit 2 detects a load acting on the servo motor from the servo amplifier 11 as a torque.

  Next, in step S102, the cumulative load calculation unit 3 acquires the torque and driving time of the servo motor from the load detection unit 2, and acquires section information from the storage unit 12, so that the cumulative load of each section and each process are obtained. Is calculated, and the cumulative load for several processes is further calculated. For example, as shown in FIG. 3, each section of the bending process includes five sections of approach, bending, pressurization, evacuation, and standby. Therefore, the cumulative load of each section is calculated, and the calculated sections are calculated. The cumulative load for one process is calculated by adding the cumulative load. Furthermore, the cumulative load for several processes is also calculated by adding the cumulative load of one process.

  In step S103, the overload determination unit 4 compares the calculated cumulative load for one process with a preset threshold value. If the cumulative load exceeds the threshold value, the overload determination unit 4 is overloaded. judge. Furthermore, the overload determination unit 4 determines whether or not the number of times determined to be overload in step S104 has exceeded the specified number. Here, when the number of times determined as overload does not exceed the specified number of times, the process returns to step S101 to continue to detect the load, and when the number of times determined as overload exceeds the specified number of times. Shifts to step S105 to display an overload message on the operation unit 13.

  When it is determined that the load is overloaded, the operation condition setting unit 5 displays a protection function selection screen as shown in FIG. 4 on the operation unit 13 in step S106, and the protection function is enabled for the operator of the press brake 10. Select whether to disable or enable. Here, when the protection function invalidity is selected, the process proceeds to step S107, where the operation condition setting unit 5 invalidates the protection function, ends the overload protection processing according to the present embodiment, and activates the protection function. Is selected, the operation condition setting unit 5 sets the protection function to be valid.

  When the protection function is set to be effective, the operation condition setting unit 5 calculates a recommended operation condition and displays it on the operation unit 13 in step S109. For example, when the current operating condition is as shown in FIG. 5 and the effective load ratio indicating the ratio of the effective load to the rated torque of the servo motor exceeds 100% and becomes 115% Then, the standby time is changed so that the effective load is lower than the rated torque, and the recommended operation condition as shown in FIG. 6 is displayed. Under the recommended operating conditions shown in FIG. 6, the standby time is changed from 0.8 s to 1.8 s, and the effective load factor is reduced to 100%. Of course, the operating conditions other than the standby time may be changed so that the effective load factor becomes 100% or less.

  Next, in step S110, the operation condition setting unit 5 displays a selection screen for selecting an operation condition setting method as shown in FIG. 7 on the operation unit 13, and is automatically set by the operator of the press brake 10 or manually set. Let them choose what to do. Here, when the automatic setting is selected, the process proceeds to step S111, where the operation condition setting unit 5 sets the recommended operation condition shown in FIG. 6 and ends the overload protection process according to the present embodiment. On the other hand, when the manual setting is selected, the process proceeds to step S112, and the operating condition is input by the operator. As an operation condition input method, the operation condition setting unit 5 displays an operation condition input screen as shown in FIG. 8 on the operation unit 13, and the operator selects an operation condition to be set and inputs an arbitrary numerical value. change.

  In step S113, the operation condition setting unit 5 determines whether or not overload is avoided under the changed operation condition. If not, the operation condition setting unit 5 returns to step S112 to re-input the operation condition. On the other hand, when an overload is avoided, the process proceeds to step S114 and the changed operating condition is set.

  For example, the operator selects the approach distance, the bending distance, and the pressurization time from the operating conditions shown in FIG. 8, the approach distance is changed from 50 mm to 30 mm, the bend distance is changed from 20 mm to 10 mm, and the pressurization time is started from 1.0 s. Change to 0.5 s and press the calculation button. The operating condition setting unit 5 calculates the effective load factor to be 100% or less by changing the operating condition other than the operating condition changed by the operator, and displays the calculation result as shown in FIG. . The calculation results shown in FIG. 9 are calculated so that the approach time, the bending time, the evacuation time, and the standby time are shortened, and the time for one process is further shortened, so that the effective load factor becomes 100%. The operator confirms this result, and if this operating condition is acceptable, the changed operating condition is set by pressing the setting button on the screen, and the overload protection processing according to the present embodiment is completed.

  As described above in detail, according to the overload protection device 1 according to the present embodiment, when it is determined that there is an overload, the operation condition that can avoid the overload by changing the operation condition of the bending machine. Therefore, it is possible to reliably avoid overload due to accumulated load.

  Moreover, according to the overload protection device 1 according to the present embodiment, when the operator selects an operation condition to be set and the value of the selected operation condition is set by the operator, the operation condition other than the set operation condition is set. Since the operating condition that can avoid the overload is set by changing the operating condition, the operator can freely change the operating condition and avoid the overload caused by the accumulated load.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and even if it is a form other than this embodiment, as long as it does not depart from the technical idea of the present invention, it depends on the design and the like. Of course, various modifications are possible.

DESCRIPTION OF SYMBOLS 1 Overload protective device 2 Load detection part 3 Cumulative load calculating part 4 Overload determination part 5 Operating condition setting part 10 Press brake 11 Servo amplifier 12 Storage part 13 Operation part

Claims (2)

An overload protection device for protecting a bending machine from overload,
Load detecting means for detecting the load of the bending machine;
Cumulative load calculation means for calculating the cumulative load by accumulating the load detected by the load detection means;
Overload determination means for comparing the cumulative load with a predetermined threshold value to determine whether or not it is an overload;
When it is determined that the overload is determined by the overload determination means, the operation condition setting means is provided for setting an operation condition capable of avoiding an overload by changing an operation condition of the bending machine. Overload protection device.   The operating condition setting means allows the operator of the bending machine to select an operating condition to be set, and when the selected operating condition is set by the operator, the operating condition other than the set operating condition is changed. The overload protection device according to claim 1, wherein an operating condition capable of avoiding an overload is set.

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