JPH03184626A - Detecting device for inclination of table of press brake - Google Patents

Abstract

PURPOSE:To prevent the generation of one-sided loading for the moving table and to safely execute bending by comparing the moved positions of both ends of the moving table provided with the upper die and outputting the alarm in case that the difference of both end positions is larger than the reference value. CONSTITUTION:The encoder E to respectively detect the moved positions of both ends of the moving table 3 provided with the punch 5 of the press brake 1 is set. The one sided loading is detected by comparing the both end positions of the moving table 3 near to their final positions. Therefore, in the state of preventing the generation of one sided loading, the bending work is safely executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a press brake table inclination detection device that can safely operate a press brake.

(Prior art) Conventional press brake table inclination detection devices mechanically detect mold inclination using limit switches, etc.
There is an example in which an alarm is output in case of extreme inclination.

(Problem to be Solved by the Invention) However, although the table inclination detection device for the press brake described above can detect relatively large inclinations without damaging the machine, it cannot detect small inclinations. There was a problem in that it was not possible to detect so-called single loads.

The so-called single load is caused by a load imbalance near both ends of the mold that occurs near the final bending position.
It is important to effectively detect this to protect the mold and improve product accuracy.

Therefore, the present invention is designed to prevent not only the large inclination of the table but also the
It is an object of the present invention to provide a table inclination detection device for a press brake that can detect up to a single load.

[Return of the invention] (Means for solving the problems) The present invention solves the above problems by interposing a workpiece between molds arranged opposite each other and moving the molds toward and away from each other. A table inclination detection device for a press brake that performs processing is provided with position detection means for detecting the movement positions of both end portions of a movable table that drives a movable mold among the molds, and moves the movable table to an appropriate number of target positions. A positioning means is provided for positioning the moving table to the final target position via the position detecting means, and the positions of both ends of the moving table detected by the position detecting means are compared in the vicinity of the final target position. The feature is that a comparison means is provided which outputs an alarm when the amount is too high.

Further, in a table inclination detection device for a press brake that performs bending by interposing a workpiece between opposing molds and moving both molds toward and away from each other, a movable mold among the molds is selected. A position detecting means for detecting the movement positions of both ends of the movable table to be driven is provided, a pair of cylinder devices driven by servo valves is provided near both ends of the movable table, and a positioning target of the movable table is determined based on bending data. An NC device is installed to calculate the value,
A hydraulic position module is provided for each servo valve and controls the servo valve by inputting the positioning command signal outputted by the NC device and appropriately switching the gain, and after outputting the positioning command signal, each hydraulic position module A first comparison means is provided for detecting an abnormal state of the servo valve and outputting an alarm by comparing the generation status of the positioning completion signal and gain switching signal fed back from the servo valve with those in a normal state, and the position detection means detects the abnormal state of the servo valve and outputs an alarm. The present invention is characterized in that a second comparing means is provided which compares the positions of both ends of the moving table near the final target position and outputs an alarm when the difference between the positions of both ends of the moving table is greater than a reference amount.

(Function) Due to the above feedback, the press brake table inclination detection device of the present invention detects a single load by comparing the two end positions of the movable table near the final bending position and detecting that the difference is larger than a preset reference value. can be detected.

Furthermore, in the press brake table inclination detection device of the present invention, in the positioning means using the hydraulic position module, the generation status of the positioning completion signal and gain switching signal returned from each hydraulic position module after the output of the positioning command signal is detected. Since the abnormal state of the servo valve is detected by comparing it with the normal state, abnormal states such as one-shaft stop state can be quickly detected based on the relationship that should exist between the positioning completion signal and the gain switching signal. By outputting an alarm at this point, a major accident can be prevented.

(Example) The present invention will be explained in detail below.

FIG. 1 is a front view of a press brake implementing the present invention.

In the figure, a press brake 1 has a lower fixed table 2 and a movable table 3 that is driven up and down with respect to the table 2.

A die 4 as a lower mold is placed on the upper part of the fixed table 2, and a punch 5 as an upper mold is attached to the lower part of the movable table 3.

In order to detect the vertical movement (D-axis direction) of the movable table 3, encoders E are installed in the frame portion (not shown) to detect the positions of both ends of the movable table 3.
is provided.

Further, in order to drive the movable table 3 up and down, cylinder devices 6 are provided at both ends of the frame portion (not shown). Both cylinder devices 6 are provided with servo valves SVI that appropriately adjust the flow rate and supply the pressure oil supplied from the hydraulic pump 7 to the cylinder devices 6.

SV2 is connected.

Furthermore, two pressure sensors P and P2 are provided in the upper cylinder chamber of the cylinder device 6 to detect the pressurizing force. One pressure sensor P1 is for low pressure, the other pressure sensor P2 is for high pressure, side pressure sensor P,
P2 is switched and used as appropriate depending on the pressure value to be detected.

Note that each table 2.3 is provided with a strain meter 8 for detecting the strain state of each table.

FIG. 2 is an explanatory diagram of a hydraulic circuit including the servo valves SVI and SV2.

In the figure, the hydraulic circuit of this example has a pair of cylinder devices 6 (CYL1, CYL2) arranged at both ends of a moving table 3 extending left and right when viewed from the front side of the press brake body. piston P
By simultaneously hydraulically driving the STIs 2, the movable table 3 is driven up and down. A rack LSCI, 2 is fixed to both ends of the moving table 3, and the rotation amount of the pinion meshed with this rack is determined by the encoder E.
By detecting this, the vertical position of the moving table 3 can be detected.

The hydraulic circuit includes an oil pump 7 that sucks oil in an oil tank OT shown at the bottom of the figure via a suction filter SFN and discharges it to a pipe OLI via a line filter ILF. The line filter ILF is provided with a pressure switch PS1 for detecting a pressure difference on the exposed blade side and detecting clogging thereof. The pipe OLI is provided with a proportional solenoid valve 5OLE for pressure adjustment, and a pressure switch PS2 for detecting a pressure increase.

A ura purifier 9 is arranged on the side of the ura tank OT.

The piping OL] includes the cylinder devices CYL1, CY.
Direction switchable and flow to drive L2 respectively!
Two adjustable servo valves 5V1SV2 are provided.

First, the circuit including the servo valve SVI on the left side of the figure is shown. The servo valve SVI is driven by the input of an electric signal so that the two ports on one side can be connected to the two ports on the other side in parallel or in a crossed manner. The two ports on one side are connected to the pipe OL] and the drain pipe OL2.

One port of the other two ports of the servo valve SVI is connected to the cylinder device CYL 1 via piping OL3.
It is connected to the upper chamber of. Also, the other port is the piping OL
4, and this piping OL4 is connected to piping OL5 via a pilot logic valve LVI.
5 is connected to piping OL6 via a counterbalance valve CBVI. Bypass piping OL equipped with a logic valve LV2 with a pilot between piping OL5 and OL, 6
7 is provided. Piping OL6 is connected to the cylinder device C.
Connected to the lower chamber side of YL 1. The logic valve L
The pilot section of the VI is connected to a pipe OL7 or a drain pipe via a solenoid valve 5OL3. Moreover, the pilot part of the logic valve LV2 is
It is connected to the piping OL6 or the drain pipe via a solenoid valve 5OL4. A pressure switch PS3 is provided in the pipe OL6.

A pipe OL8 is connected to the upper chamber of the cylinder device CYL1, and a drain pipe is connected to the pipe OL8 via a logic valve LV3 with a pilot. The pilot part of this logic valve LV3 is a solenoid valve 5OL5.
The pilot pressure of the pipe OL1 can be inputted via the pipe OL1.

The same applies to the other cylinder device CYL2. Corresponding parts are indicated with the same reference numerals. A pressure sensor SD is provided between both pipes OL3.

In the above return hydraulic circuit, for example, for the left circuit, the servo valve SVI is in the state shown, and the piping O
It is assumed that pressure oil flows into the upper chamber of the cylinder device CYL1 via L1. Then, the solenoid valve 5O is turned on based on the turning-on operation of the descending foot pedal (not shown).
L3 opens the logic valve LVI, and the oil in the lower chamber flows into the pipe OL4 via the pipe OL6, the counterbalance valve CBV1, and the logic valve LVI.

On the other hand, when servo valve SV1 is operated in the opposite direction, piping OL
The pressure oil I flows into the lower chamber of the cylinder device CYLI through the pipe OL4.0L5, the logic valve LV2, and the pipe OL6, and raises the ram 1.

The same applies to the cylinder device CYL2. During this time, the pressure sensor SD is detecting the pressure in the pipe OL3.

FIG. 3 shows the NC device 10 and hydraulic position module 11 (1) that control the servo valves (SVI, 5V2) for the pair of D axes (DI axis, D2) as described above, and the hydraulic position module 11 (1), A
, 11B).

The NC device 10 includes target value calculation means 1 for controlling the positioning of the moving table 3 according to the input bending data.
2, and the first and second timers 13゜14.13-14
- (also referred to as timers 1, 2, 3.4).

Further, a single load detection section 16 is provided.

The hydraulic position modules IIA, IIB are fed back in a closed loop to obtain a feedback signal of the encoder E to the servo valves SV1, SV2, and are fed back to the servo valves SVI, S in order to drive the movement table 3 to the input target value.
Outputs a control signal (voltage) to V2.

The NC device 10 and each hydraulic position module IIA
, IIB are connected by a serial communication line, and the NC device 10 outputs a positioning command signal 0P16 to both modules IIA and IIB. Positioning command signal 0P
16 is a command including a target position and a command speed for the target position.

Each hydraulic position module IIA, IIB operates individually and attempts to individually move said moving table 3 to a target position. At this time, in order to perform highly accurate machining, a speed switching position and a gain switching position are set in each hydraulic position module 11A111B, and the speed switching and gain switching are performed at the set positions.

Therefore, in this example, when this gain switching is performed, a gain switching signal OP42 is generated and this is sent to the NC device 1.
I am trying to send it to 0. Further, a positioning completion signal 0P44 is sent out at the timing shown in FIG.

As shown in FIG. 4, in step 401, the NC device 1
0 outputs the positioning command signal 0P16 to both hydraulic position modules IIA and IIB, step 4
02.40B with both position modules IIA and IIB
performs positioning tasks simultaneously in multitasking. Also, during execution, the abnormality determination circuit 15 of the NC device 10
Each module 1 performs the processing shown in Figures (a) and 6(b).
Execute for 1A and IIB. Furthermore, after that, the single load detection section 16 detects the single load.

First, the control diagram shown in FIG. 5 will be explained. The solid line shows the command value, and the broken line shows the actual value. Time t is on the horizontal axis, D is on the vertical axis
Take the axis. ■ to ■ indicate examples of abnormal states.

In the figure, D2 shows the gain switching position, D3 shows the speed switching position (target position), and D4 shows the final target position. Target value D
It is assumed that the positioning completion signal for No. 3 is output at the position D1, for example, 4 mm before the target value D3.

However, the positioning completion signal is output after a certain period of time (for example, 60 m5) after arriving at the position. In addition, D
The distance between 2.03 and 2.03 is about 1 mm.

In the above control diagram, as shown by the solid line, the moving table 3 initially moves at a high speed, is decelerated from the gain switching position, temporarily stops at the target position D3, and then moves at a low speed to the final target position D4. At this time, in the normal state, the positioning completion signal 0P44 is outputted on the condition that 6Qms have passed since entering the positioning opening. Further, a gain switching signal 0P42 is output at position p2. During normal operation, the time from position D1 to D3 via D2 is very short, so the positioning completion signal 0P44 is output after reaching the target position D3.

Now, the abnormality determination circuit 15 of the NC device 10 executes determination processes I and (2) shown in FIGS. 6(a) and 6(b). FIG. 6(a) shows processing for module 11A,
FIG. 6(b) shows the processing for module 11B.

Since the process shown in FIG. 6(b) is relative to the process in FIG. 6(a), corresponding steps are indicated by the same number followed by a dash ('). The time set in the first timer 13.13' is 0.15 to 0.3
7 seconds, the time set in the second timer 14.14' is 1
It is about seconds.

In FIG. 6(a), when the gain switching signal 0P42■ is input in step 101, the first
The timer 13 is set to a time of 0.15 to 0.37 seconds.

In step 603, the input of the positioning completion signal 0P44■ is determined, and the step 604 continues until the input of the positioning completion signal 0P44■.
The timeout of the timer 13 is determined, and if the positioning completion signal 0P44■ is not input before the time elapses, an alarm is generated in step 605. Thereby, it is possible to determine an abnormal state in which the positioning completion signal 0P44■ is not inputted easily.

Next, until the time-up of timer 1 is confirmed in step 604, the positioning completion signal is 0 in step 603.
If P44@ is input, the module 11A is normal to this extent. Therefore, in steps 606 and subsequent steps, the relationship with other modules 11B is examined.

At step 606, it is determined whether or not the gain switching signal 0P42e for another module (2) has been input. If not, an alarm is output at step 610 as the modules are not balanced.

Furthermore, if the gain switching signal 0P42■ for the other module IIB is input in step 606, the second timer 14 is started in step 607, and during this time, in steps 608 and 609, the positioning completion signal for the other module IIB is input. It is determined whether or not 0P44■ has been input. If no input is made during this time, step 61
Outputs an alarm when the value is 0. Therefore, step 607
Through the processing in steps 609 to 609, it is possible to determine the delay in the positioning completion signal of another module IIB.

Regarding FIG. 6(b), the processing for module 11B is similarly executed.

Therefore, in this example, by inspecting the delay of the positioning completion signal with respect to the gain switching signal, and the delay of the gain switching signal and positioning completion signal between modules, various types of errors such as single-axis stop can be detected for conditions different from normal ones. It can determine abnormal conditions and output alarms.

As a result of the above, the moving table 3 is moved to the target position D4 in a normal manner.
It will descend close to you. Therefore, in this example, the fourth
Processing (2) shown in step 404 in the figure is executed.

The details of this process (1) are shown in FIG.

In step 701, the detection positions D2 for both axes D1 and D2 are input.

In step 702, a comparison is made using the following equation.

D, -(D2 +DS)l≧α α is a parameter, and is a value that can be arbitrarily determined by the user. Specifically, in order to detect a single load, 0.
This value is set to about 0.05 mm. DS is an offset value. The offset value DS is set when the moving table 3 is intentionally tilted during work.

Therefore, in step 702, when both axes are loaded and the difference between the detected values of D2 is greater than the set value α, this is regarded as a one-sided load, and an alarm is output in step 703.

As described above, in this example, single loads can be accurately detected, and product defects and mold damage due to single loads can be prevented.

Furthermore, since various abnormal states of both shafts Dr and D2, such as one shaft stopping, are detected in the processes (1) and (2) shown in FIG. 4, safe and reliable bending operations can be performed in all operations.

The present invention is not limited to the above-mentioned discrimination method, but by discriminating the gain switching signal 0P42 under various conditions,
Various abnormal conditions can be determined. For example, N.C.
Since the device also manages the position of the encoder,
Depending on the current state at the time when the gain switching signal 0P42 is input or when it is not input, if the preset normal state is not entered, all other states are determined to be abnormal and an alarm is output, etc. I can do it.

The present invention is not limited to the above embodiments, but can be implemented in any appropriate manner by making appropriate design changes.

[Effects of the Invention] The present invention is a table inclination detection device for a press brake that detects the unbalanced load near the final bending position based on the difference between the positions of both ends of the moving table. able to perform work. In addition, if the abnormal state is determined using the gen switching signal,
Abnormal conditions such as one shaft stopping can be quickly detected.
It is possible to prevent a major accident from occurring.

[Brief explanation of drawings]

The drawings all show embodiments of the present invention, and Fig. 1 is a front view of the press brake, Fig. 2 is an explanatory diagram of the hydraulic circuit, Fig. 3 is an explanatory diagram of the NC device and the hydraulic position module, and Fig. 4 is an explanatory diagram of the hydraulic position module.
The figure is a flowchart showing an overview of the processing of the NC device.
The figure is a control diagram of the hydraulic position module, FIGS. 6(a) and 6(b) are flowcharts showing an abnormality determination routine for each axis, and FIG. 7 is a flowchart showing a single load detection method. 3...Moving table 10...NC device 11 (IIA, 1.1B)...Hydraulic position module 0P16...Positioning command signal 0P42...Gain switching signal 0P44...Positioning completion signal S■1 , SV2... Servo valve LSCI, 2... Rack E... Encoder P16 0 Figure 5

Claims (2)

[Claims] (1) In a table inclination detection device for a press brake that performs bending by interposing a workpiece between opposing molds and moving both molds toward and away from each other, a movable mold among the molds; position detecting means for detecting the movement positions of both end portions of a moving table that drives the moving table, positioning means for positioning the moving table to a final target position via an appropriate number of target positions, and the position detecting means detecting The press brake table is characterized in that it is provided with comparison means for comparing the positions of both ends of the moving table near the final target position and outputting an alarm when the difference between the positions of both ends of the moving table is greater than a reference amount. Tilt detection device. (2) In a table inclination detection device for a press brake that performs bending by interposing a workpiece between opposing molds and moving both molds toward and away from each other, a movable mold among the molds; A pair of cylinder devices driven by servo valves are provided near both ends of the movable table to determine the position of the movable table based on bending data. An NC device is installed to calculate the target value,
A hydraulic position module is provided for each servo valve and controls the servo valve by inputting the positioning command signal outputted by the NC device and appropriately switching the gain, and after outputting the positioning command signal, each hydraulic position module A first comparison means is provided for detecting an abnormal state of the servo valve and outputting an alarm by comparing the generation status of the positioning completion signal and gain switching signal fed back from the servo valve with those in a normal state, and the position detection means detects the abnormal state of the servo valve and outputs an alarm. A press characterized in that a second comparing means is provided for comparing the positions of both ends of the movable table near the final target position and outputting an alarm when the difference between the positions of both ends of the movable table is greater than a reference amount. Brake table tilt detection device.