JPH0839298A - Slide stop time measuring instrument of press machine - Google Patents

Abstract

PURPOSE:To measure the true stop time of a slide by counting clock pulses in correspondence to movement of this slide, storing these clock pulses and executing arithmetic processing by using the stored value and the moving quantity between the pulses of an encoder upon receipt of the stop signal of the slide. CONSTITUTION:The pulse signals from an encoder 1 which transmits signals in correspondence to the movement of the slide of the press machine are inputted to a stop deciding means 2 and a storage means 3. A counter 8 starts counting of the pulses from a clock pulse transmitter when the stop signal 6 of the slide is applied thereto. The counted value is inputted to the storage means 3. The timer of the preset stop decision time is started in the stop deciding means 2 and whether the next pulse is inputted from the encoder 1 before timing up or not is monitored. The means makes decision that the slide is held stopped unless the pulse is inputted. The stop signal 6 is then outputted to an arithmetic means 4. This arithmetic means 4 reads the stored count value from the storage means, calculates the stop time of the slide and outputs the stop time to a stop time display 5.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Used for measuring the slide stop time of press machines.

[0002]

2. Description of the Related Art The slide stop time of a press machine is the time from when a slide stop signal is given to when the slide stops. Conventionally, there are the following techniques depending on the slide stop determination method.

The first prior art example, Japanese Utility Model Laid-Open No. 55-134099
Then, the forward / reverse determination circuit is used to determine the stop using an encoder that transmits a two-phase pulse that can determine the rotation direction, and the time until this determination is defined as the slide stop time.

In the second conventional example, Japanese Patent Laid-Open No. 62-93687, when a pulse signal is not output from the encoder for a certain period of time, it is determined to be stopped, and the time until this determination is set as the slide stop time.

[0005]

Problems to be Solved by the Invention In the first conventional example,
The time from the true slide stop until the reverse rotation starts and the reverse rotation pulse is transmitted and the forward / reverse rotation determination circuit determines that it is stopped,
Since it is included in the slide stop time, the value is larger than the true slide stop time. However, not all press machines reverse when the slide is stopped. In such a case, it is impossible to determine the stop of the slide, so that the stop time of the slide cannot be measured.

In the second conventional example, the slide stop time is included in the slide stop time, which is a fixed time for the determination in the maximum case depending on the timing of the pulse transmission immediately before the true slide stop. Further, it is not clear how much the stop determination time is set to make sure that the slide is stopped. Therefore, the stop determination time must be set to a value larger than the required minimum value, and it was also measured in this conventional example. The slide stop time has a value larger than the true slide stop time.

The slide stop time of the press machine is used to determine the position of various safety devices of the press machine to protect the press operator. The slide stop time of the conventional example is measured by a measuring device having a value larger than the true value as described above, and since there are various methods for determining the slide stop, the value of the slide stop time also becomes various. There is.

If the position of the safety device is determined based on these measured values of the slide stop time and the safety device is attached to the press machine, the distance from the working area of the press machine to the safety device increases. However, since the degree of increase is various, it is a cause of confusion in the field where the press machine is used. Moreover, the increase of this distance will reduce the efficiency of press work.

In order to reduce the increase in the distance from the working area of the press machine to the safety device and bring it closer to the true slide stop time, the encoder used in the conventional example has a small moving amount between pulses, in other words, has a high resolution. I am using a high encoder, but it is still above the true slide stop time.

[0010]

In order to solve the above problems and to measure the true slide stop time, the present invention oscillates a clock pulse and an encoder that outputs a pulse signal corresponding to the movement of the slide. An oscillator, a counter that counts clock pulses after a slide stop signal is given, a storage unit that sequentially stores the count value that is the value of the counter each time an encoder pulse is input, and a sufficient margin for a fixed time. Stop determination means for determining that the slide stop is detected by detecting that the pulse signal from the encoder is not output during a certain stop determination time.

In response to the output of the stop signal from the stop judging means,
The calculation means uses the count value stored in the storage means, that is, the elapsed time after the slide stop signal is output and the movement amount between the pulses of the encoder to calculate the stop time and display the stop display. The stop time of the slide is displayed on the container.

[0012]

After the slide is determined to be stopped by the stop determination means, the count values sequentially stored in the storage means at a time close to the stop (for example, just before the slide is stopped) (this value is the slide stop signal is output. Is the elapsed time from the start to the time of each pulse transmission)
The average speeds V12, V23, and V13 between T1 and T2, between T2 and T3, and between T1 and T3 are calculated from 1, T2, and T3 and the movement amount between the pulses of the encoder, and from these average speeds V12 and V23. Average acceleration A13 between T1 and T3
Ask for.

From these values, the time T until the average velocity V13 between T1 and T3 stops at the average acceleration A13
C is obtained, and the time T13 + TC obtained by adding the elapsed time T13 from the slide stop signal at the time of V13 and the time TC until the stop is set as the slide stop time.

The above-mentioned means uses one set of three stored count values to obtain the slide stop time, but a plurality of sets of stored count values are used to stop the slide from each. The time may be obtained and the average value may be used as the slide stop time. Further, if the average value is used, the accuracy of the encoder can be corrected.

Further, a plurality of sets of stored count values are used to determine the slide stop time from each, and when the calculated slide stop time draws a quadratic curve, it is assumed that the slide stop is performed on the curve. The value obtained in step may be used as the slide stop time.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A block diagram of FIG. 1 and an algorithm of FIG. 2 showing the whole embodiment of the present invention will be described. A pulse signal from an encoder (1) which is provided on a slide portion of a press machine and which emits a pulse in response to the movement of the slide is input to a stop determination means (2) and a storage means (3). The clock pulse transmitter (7) emits pulses at regular time intervals. When the slide stop signal (6) is given from the press machine, the counter (8) starts counting the pulses from the clock pulse oscillator (7).

The counted value of the counter (8) is input to the storage means (3), and the encoder (1)
Each time a pulse signal is output from, it is sequentially stored in the storage means (3). This work is sequentially performed until the pulse signal is no longer output from the encoder (1) (until the slide stops), and the stored count value is until the next slide activation signal (9) is output from the press machine. Hold.

On the other hand, the stop determination means (2) is equipped with a timer for the stop determination time preset in the stop determination means (2). This timer starts each time a pulse transmitted from the encoder (1) is input, and monitors whether the next pulse is input from the encoder (1) before timing out, and if no pulse is input, slides. Judges that it has already stopped, and outputs a stop signal to the calculating means (4). The count value of this counter (8) is held until the slide activation signal (9) is output from the next press machine.

Upon receiving the stop signal, the calculating means (4) reads the stored count value from the storage means (3), calculates the slide stop time, and outputs it to the stop time indicator (5).

The calculation for determining the stop time will be described with reference to FIG. 3, which is an embodiment of the present invention. In this figure, the horizontal axis shows elapsed time, and the vertical axis shows the change status of the slide speed of the press machine and the pulse output status of the encoder. At the point A, a slide stop signal is output. After a time lag from point A, the slide speed gradually decreases.
The pulse output interval of the encoder (1) becomes wider as the slide speed decreases.

After the stop judging means (2) judges that the slide is stopped, the count values T1, T2 and T3 which are sequentially stored in the storage means (3) are selected, and the encoder (1) is selected.
Let S be the amount of movement between the pulses of T, between T1 and T2, and T2
And the average speed V12 between T3 and T3 between T1 and T3,
V23 and V13 are as follows. V12 = S / (T2-T1) V23 = S / (T3-T2) V13 = S / (T3-T1)

From V12 and V23, the average acceleration A13 between T1 and T3 is as follows. A13 = (V23−V12) ÷ (T3−T1) ÷ 2 The time TC until V13 stops at the average acceleration A13 is as follows. TC = −V13 ÷ A13 The elapsed time T13 from the application of the stop signal to the slide to the point of V13 is as follows. T13 = (T1 + T3) / 2

From the above, the slide stop time T is calculated by T = T13 + TC, and this value T is displayed on the stop time indicator (5).

The encoder (1) may be provided in the crankshaft portion of the press machine and replaced with an encoder that emits a pulse corresponding to the rotation of the crankshaft, or provided in the screw shaft portion that drives the slide of the press machine, Obviously, an encoder that emits a pulse corresponding to the rotation of the screw shaft may be substituted.

In this method, even if it takes a long time to determine whether or not to stop,
As described above, after the slide stop is determined, the count value before the slide is stopped is used to calculate the stop time, which is the slide stop time used for display or control, so the resolution of the encoder is low. Even with an encoder used in a digital rotary cam normally used in a press machine (a large amount of movement between pulses), and even if the stop determination time is long, the slide stop time measurement accuracy can be maintained.

From the above description, the present invention has the following effects. 1) It is possible to measure the true slide stop time, which does not include the stop determination time which is the time used for the slide stop determination. 2) It is not necessary to increase the resolution of the encoder and shorten the stop determination time. Even if the stop determination time is set to a sufficiently large value by using an encoder with low resolution, the correct slide stop time can be measured. 3) The correct true slide stop time can be measured for a press machine having a mechanical press, a hydraulic press, or a screw press.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is an algorithm according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a calculation which is an embodiment of the present invention.

[Explanation of symbols]

1 is an encoder, 2 is a stop determination means, 3 is a storage means, 4
Is a calculation means, 5 is a stop time indicator, 6 is a slide stop signal, 7 is a clock pulse transmitter, 8 is a counter, and 9 is a slide activation signal.

Claims (3)

[Claims] 1. An encoder that outputs a pulse signal in response to movement of a slide of a press machine, an oscillator that oscillates a clock pulse, and a counter that counts the clock pulse after a stop signal is given to the slide. A storage unit that stores the value of the counter each time a pulse of the encoder is input, a stop determination unit that determines that the pulse signal from the encoder has not been output for a certain period of time, and determines whether the slide is stopped, After the stop determination, 3 of the counter value stored in the storage means at a time close to the stop
Each value is set as one set, and the average speed and the average acceleration of the slide at that time are calculated by the calculating means from the value of the counter of at least one set and the moving amount of the slide between the pulses of the encoder, and then the average speed. To the time required for the slide speed to reach zero by moving at the average acceleration,
The slide stop time of the press machine is defined as the slide stop time, which is the value obtained by adding the elapsed time up to the point of time when the average speed and the average acceleration are obtained after the slide stop signal is given. measuring device. 2. A slide stop of a press machine according to claim 1, wherein an encoder that outputs a pulse signal in response to slide movement is replaced with an encoder that outputs a pulse signal in response to rotation of a crankshaft. Time measuring device. 3. The press according to claim 1, wherein an encoder that outputs a pulse signal in response to movement of the slide is replaced with an encoder that outputs a pulse signal in response to rotation of a screw shaft that moves the slide. Machine slide stop time measuring device.