JPS5952039B2 - Automatic fixed position stop device in variable speed press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic fixed position stopping device for a variable speed press. The present invention relates to an automatic fixed position stopping device for a variable speed press.

Generally, in a variable speed press, when the operating speed of the press is changed, the movement speed of the slide, the rotational speed of the crankshaft, etc. change, and the inertia of the slide, crankshaft, etc. also changes.

For this reason, if the timing of generation of a stop signal to the brake is fixed regardless of the operating speed of the press, there is a problem in that the stop position of the slide changes.

Therefore, in the past, several cam switches were installed on the crankshaft, etc., and the cam switch appropriate for the operating speed of the press was selected, and the cam switch was used to perform controls such as giving a stop signal to the brake.

However, since the control is performed in stages, there are problems such as variations in stop positions and complicated cam switch selection operations, and the above problems cannot be effectively solved.

This invention effectively solves the above problems, and its purpose is to provide a stepless stop signal to the brake according to the operating speed of the press, so that the slide always remains at the top dead center position. An automatic fixed position stop device for a variable speed press is provided.

Hereinafter, a preferred embodiment of the present invention will be described based on the accompanying drawings.

Figure 1 is an explanatory diagram of the operation of the variable speed press, where 1 is the flywheel, 3 is the transmission, mainly the clutch,
It consists of a brake, a speed reduction mechanism, etc., and 5 is a crankshaft.

The flywheel 1 is rotated by a rotational drive device (not shown), and the rotational output of the flywheel 1 is
It is transmitted to the crankshaft 5 via the transmission 3.

As the crankshaft 5 rotates, a slide (not shown) moves up and down to perform press working.

Note that the transmission 3 is for decelerating, transmitting, or stopping the rotational output of the flywheel 1.

Next, the automatic fixed position stopping device 7 of this embodiment will be explained. As shown in FIG. The stop signal generating device 11 generates a stop signal at a corresponding timing.

First, the rotational speed detection device 9 will be explained. The rotational speed detection device 9 mainly includes a detector 13 such as a limit switch, an oscillation circuit 15 that oscillates pulses, and an oscillation circuit 15 that generates pulses according to the output of the detector 13. It consists of a counter 17 and the like that counts up the number of pulses output from the circuit.

The detector 13 is fixed to the press body near the flywheel 1, and detects the detected object 13b provided in the speed detection section θ1 to θ2 on the outer circumference of the flywheel 1. It is turned on for a time t proportional to the rotation period of the wheel 1.

The output of the detector 13 is, for example, a photocoupler,
The waveform shaping circuit 19, which is an R-S flip-flop, performs insulation, level shifting, noise absorption, waveform shaping, etc.

The oscillation circuit 15 is composed of, for example, a timer IC, and a variable resistor 21 is connected as an external resistor to the timer IC, and the pulse period of the output pulse is changed by changing the resistance value of the variable resistor 21. Adjust.

The output of the waveform shaping circuit 19 and the oscillation circuit 15
The output of is logically ANDed by the AND circuit 23, and
The output of this AND circuit 23 is input to the counter 17.

The counter 17 is composed of, for example, an up/down counter IC capable of presetting count data, and the data set by the data setting circuit 25 becomes the data to be preset.

The output of the waveform shaping circuit 19 is connected to a differential pulse generating circuit 27, and the output of the differential pulse generating circuit 27 is input to the counter 17 as a preset data load signal.

At the rising edge of the input signal, the differential pulse generation circuit 27
It generates pulses.

Next, the stop signal generation device 11 will be explained. This stop signal generation device 11 mainly includes a detector 31 such as a limit switch, an oscillation circuit 33 that oscillates pulses, and an oscillation circuit 33 that responds to the output of the detector 31. It consists of a counter 35 and the like that counts down the number of pulses output from the counter 35.

The detector 31 is fixed to the press body near the crankshaft 5, and detects the detected object 31b provided at the operation start point β1 on the outer circumference of the crankshaft 5, when the slide is at the bottom dead center. It turns on when it passes through and begins the upward stroke.

The output of the detector 31 is, for example, a photocoupler,
A waveform shaping circuit 37 consisting of an integrating circuit etc.
Level shifting, noise absorption, waveform shaping, etc. are performed.

Further, the output of the waveform shaping circuit 37 is connected to the input of a flip-flop 39 (in this embodiment, the tarock input of the flip-flop is used for J-), and when the detector 31 is turned on, the flip-flop P39
is set.

The oscillation circuit 33 is composed of, for example, a timer IC, and the output of the oscillation circuit 33 is ANDed by the flip-flop AND circuit 41, and the output of the AND circuit 41 is fed to the counter 35. connected to the countdown input of

The counter 35 is composed of, for example, an up/down counter IC capable of presetting count data, and the output data from the counter 17 becomes the preset data.

Then, an AND circuit 43 performs a logical product on the inverted signal of the output of the waveform shaping circuit 19 and the inverted signal of the output of the flip-flop 39, and the output of the AND circuit 43 is used as a reset signal. It is manually input to the counter 35 as the evening load signal.

The output value of the counter 35 is connected to a borrow detection circuit 45 which detects when the output value becomes negative.

The borrow detection circuit 45 is composed of, for example, a gate and a monostable multivibrator, and outputs a signal that becomes low level for a certain period of time when the input voltage becomes negative.

The output of the borrow detection circuit 45 is transmitted to an amplifier 47.
is connected to a clutch/brake relay 49 for operating the clutch/brake of the transmission 3.

Next, the automatic fixed position stopping device 7 having the above configuration is installed.
The operation will be explained.

First, when the flywheel 1 is rotating, the detected object 13b provided on the flywheel 1 is detected by the detector 13.
Each time the flywheel 1 rotates to the position, the detector 13 is turned on, and the waveform shaping circuit 19 generates a square wave that is turned on for a time t every time the flywheel 1 rotates, as shown in the timing chart of FIG. A signal T1 is output.

The signal T1 is then input to a differential pulse generating circuit 27, which outputs a signal T2 that generates a pulse at the rising edge of the signal T1.

The signal T2 is input to the counter 17 as a load signal for the preset value of the counter 17.

Therefore, at the rising edge of the signal T1, the internal register of the counter 17 is loaded with data B set by the data setting circuit 25 (set to negative in this embodiment).

Also, the AND circuit 23
The gate of is opened, and the pulse signal T4 oscillated from the oscillation circuit 15 is inputted as a count-up input of the counter 17.

Therefore, the count 1 to data output D3 of the counter 17 becomes data B at the rising edge of the signal T1, and thereafter continues to count up the number of pulses of the pulse signal T4.

Then, at the fall of the signal T1, the gate of the AND circuit 23 is closed, the counter 17 stops counting up, and the count output data D3 of the counter 17 holds the final count data A.

Therefore, the value of data A is proportional to the time that the detector 13 is on, and the time t that the detector 13 is on is proportional to the rotation period of the flywheel 1, so the data The value of A is proportional to the rotation period of the flywheel 1.

When the detector 13 is off and the detector 31 is also off, the output signal T5 of the AND circuit 43 turns on at the falling edge of the signal T1.

Therefore, the final count output value of the counter 17 is
A is loaded into an internal register of counter 35.

The above operations are performed every rotation of the flywheel 1, independent of the rotation of the crankshaft 5.

Next, when the press is started, the clutch of the transmission 3 is engaged and the brake is released, the rotational output of the flywheel 1 is transmitted to the crank shirt 1-5, and the crankshaft 5 starts rotating.

A detected object 31 provided on the crankshaft 5
When b rotates to the position of the detector 31, the detector 31
is turned on, the signal T8 is output to the waveform shaping circuit 37, and the signal T8 is further input to the flip-flop 39, which is set and the signal T9 is output.

When the signal T9 is turned on, the gate of the AND circuit 41 is opened, and the output pulse T7 oscillated from the oscillation circuit 33 is input as a countdown input to the counter 35.

Therefore, the count output data D6 of the counter 35 is
The number of output pulses T7 continues to be counted down sequentially from the preset value of data A.

As a result of the above-mentioned countdown operation, the count output data D6 finally becomes negative, and the output signal T10 of the borrow detection circuit 45 becomes low level for a certain period of time, and is transmitted through the amplifier 47 to the clutch/brake signal. relay 49 is activated.

Therefore, the timing at which the clutch/brake relay 49 operates is after a time period corresponding to the value of data A has elapsed since the detector 31 was turned on.

When the clutch/brake relay 49 operates, l
- The clutch mechanism of the transmission 3 is disconnected, and at the same time, the brake mechanism is interlocked to perform a braking action, causing the crankshaft 5 to slip and come to a stop.

In this case, the slip angle can be approximately regarded as a linear function of the stroke number, so after the detector 31 is turned on as described above, the clutch brake By activating the relay 49, the stop position remains the same regardless of changes in press speed.

Further, the pulse period of the oscillation circuit 15 is controlled by a variable resistor 21.
Accordingly, by making appropriate adjustments, the stop position can always be set at the top dead center position.

Further, at the same time as the signal TIO operates the clutch/brake relay 49, the flip-flop 39 is reset to 1 and the gate of the AND circuit 41 is closed.

Then, the counter 35 stops counting down,
At the same time, the signal T5 becomes high level, and the count output data D3 of the counter 17 is again preset to prepare for the next press cycle.

The abnormality detection circuit 29 detects when the count output data D3 of the counter 17 becomes a certain abnormal value. Used for safety control.

Next, to explain the second embodiment, as shown in FIG. 4, the rotational speed of the crankshaft 5 is detected in the interval α1 to α2 near where the crankshaft 5 passes the bottom dead center and enters the upward stroke. The detector 13 and the object to be detected 13b are provided so as to be able to do so.

Then, instead of the detector 31 of the stop signal generating device 11, the b contact of the detector 13 is used, or the output of the waveform shaping circuit 19 is inverted and input to the flip-flop 39.

If the other configurations are the same as those of the first embodiment, the rotational speed detection device 9 will detect the rotational speed of the crankshaft 5 instead of detecting the rotational speed of the flywheel 1. , actions and effects, etc. are as described in Section 1 above.
It will be the same as the example.

Further, in the second embodiment described above, it is also possible to implement the detector 13 and the detected object 13b so as to detect the vertical movement speed of the slide.

As can be understood from the above description of the embodiments, the gist of the present invention is as described in the claims, and as is clear from the description, the first counter is connected to the flywheel or crank The rotation speed of the flywheel or flank shaft is detected by counting pulses emitted from a pulse oscillation circuit for a time proportional to the rotation period of the shaft, and at the same time as this first counter starts counting, the first counter Negative data is set in the counter by the action of the data setting circuit.

Therefore, the first counter starts counting from a negative value.

In addition, the second counter converts the pulse oscillated from the pulse oscillation circuit from the count value of the first counter when the detector detects the object to be detected provided at the operation start point on the outer circumference of the crankshaft. It oscillates a stop signal when the subtraction count becomes negative or zero.

Therefore, for example, if the rotational speed of the flywheel or crankshaft is extremely high and the second counter starts subtractive counting while the count value of the first counter is negative or zero, the subtractive count is already negative or zero. At the same time as starting, a stop signal will be oscillated.

That is, in this case, the stop signal can be generated at the same time as the detection of the rotational speed of the flywheel or crankshaft is completed.

Therefore, even when the operating speed of the press is changed and the press rotates at a high speed, the crankshaft can be stopped at the top dead center.

Furthermore, as is clear from the above configuration, the present invention counts the pulses oscillated from the pulse oscillation circuit and does not use a pulse encoder or the like, so the configuration is extremely simple and can be provided at low cost. It is something that can be done.

Further, since no expensive equipment is required to detect the press speed, and the detector and the object to be detected can be roughly set, it is economically advantageous.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may be implemented in other embodiments.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the operation of the variable speed press, Fig. 2 is a block diagram of the automatic fixed position stopping device according to the present invention, Fig. 3 is an explanatory diagram of the operation of the automatic fixed position stopping device, and Fig. 4 is an illustration of the operation of the automatic fixed position stopping device according to the present invention. It is an explanatory diagram in an example. (Explanation of main symbols shown in the drawings), 13b...
...Object to be detected, 13...Detector, 15...
...Oscillation circuit, 17...Counter, 9...
... Rotation speed detection device, 11 ... Stop signal generation device, 1 ... Flywheel, 5 ...
··Crankshaft.

Claims (1)

[Claims] 1 A flywheel 1 and a crankshaft 5 in a variable speed press are connected via a transmission 3, and pulses oscillated from a pulse oscillation circuit are counted for a time proportional to the rotation period of the flywheel 1 or crankshaft 5. a first counter 17 that detects the rotational speed of the flywheel 1 or crankshaft 5; and a data setting circuit 2 that sets negative data to the first counter 17 at the same time as the tenth counter 17 starts counting.
5, a detector 31 that detects the detected object 31b provided at the operation start point on the outer periphery of the crankshaft 5, and a pulse oscillation circuit that oscillates when the detector 31 detects the detected object 31b. An automatic fixed position stop device for a variable speed press, comprising a second counter 35 that oscillates a stop signal when the count value of the first counter subtracts pulses and becomes negative or zero. .