JPS5823518Y2 - Press overrun detection device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an overrun detection device for a variable speed press.

Conventional constant-speed presses detect the number of strokes from a limit switch that operates according to the press stroke or from a pulse generator that generates pulses according to the rotation angle, and detect an overrun when the number exceeds a preset number. Detected.

However, in a variable speed press, the slip angle changes depending on the number of strokes of the press, so it is difficult to detect overrun using the above detection method.

Conventionally, the overrun detection amount is changed according to the number of press strokes, but since it does not detect the true value of overrun, it has the drawback of lacking detection accuracy.This invention was made with the aim of eliminating this drawback. By focusing on the fact that the number of press strokes and the bevel angle are almost proportional, we provide a press overrun detection device that detects overruns from the slip angle according to the number of strokes, thereby achieving highly accurate overrun detection. This made detection possible.

This invention will be described in detail below with reference to an illustrated embodiment.

In the figure, 1 is a pulse generator attached to the main shaft of the press (not shown), 2 is a driving electric motor and a shift flywheel (
This is a detector installed in the clutch that transmits power to the main shaft via the main shaft (both not shown), and when the clutch is disengaged and the brake is activated, the gate 3 is opened, and the counter 4 is thereby activated. Count the pulses from pulse generator 1.

5 is D for converting the count value of counter 4 into DC voltage.
/A converter, and the output of this D/A converter 5 changes in proportion to the slip angle in accordance with the number of press strokes, as shown in FIG. 2a.

On the other hand, 6 is a rotation detector that detects the entire rotation speed of the flywheel (not shown) and generates a voltage proportional to the number of press strokes (Fig. 2b). Even if the flywheel is stopped, the rotation of the flywheel, which continues to rotate, is detected and a voltage proportional to the number of strokes is output.) The output of this rotation detector 6 is the output a from the D/A converter 5. It is set very high.

In other words, when the clutch is turned off to stop the press,
The total nine angles due to coasting due to inertia are approximately constant when the number of strokes is constant as in a constant speed press.

However, when using a variable speed press like this one, the sliding angle changes depending on the number of strokes.

This sliding angle varies somewhat depending on when the power is turned off and the precision of the machine, but it is approximately proportional to the number of strokes.

Therefore, considering the above-mentioned variations, the limit of the bevel angle for each number of strokes is determined in advance. As the number of strokes increases, the variation also increases, so when the number of strokes is small, b - a = small, and when the number of strokes is large, b - a = large.

When the slip angle exceeds the above output value, this is automatically detected as a run, and the output of the rotation detector 6 is input to the comparator I together with the output of the D/A converter 5. are compared.

Comparator 1 compares both inputs, and when the output of D/A converter 5 exceeds the output of rotation detector 6, it outputs an overrun signal to relay circuit 8, and relay circuit 8 operates to detect an overrun. I am told to do so.

Therefore, when the press stroke number is X rpm, the normal slip angle is 10 degrees (the output of the D/A converter 5 is 5 ■)
If the output of the rotation detector 6, which is proportional to the number of strokes, is 6V, and if the rotation angle increases to 13 degrees due to a cause such as brake wear, then from Fig. 2, the D/A The output of the converter 5 becomes 6.5V, and the voltage edge voltage a becomes large. Accordingly, an overrun signal is outputted from the comparator 7 to the relay circuit 8, and the relay circuit 8 operates to detect an overrun.

That is, when the press stroke number is X rpm, if the slip angle is 93 degrees greater than the normal value, this can be detected as an overrun.

On the other hand, when the press stroke number is, for example, YrpmO, the normal slip angle is 26 degrees (the output of the D/A converter 5 is 13
), if the slip angle increases by 6 degrees or more, rotation detector 6
Comparator 7 outputs an overrun signal beyond the output of
The relay circuit 8 can now detect this.

In other words, when the number of press strokes is small, an overrun can be detected with a small υ angle, and when the number of press strokes is large, an overrun can be detected with a large υ angle. Worry less.

As detailed above, this device detects the sliding angle of the press slide as a voltage and compares this with a voltage proportional to the number of press strokes, and detects that the sliding angle detection voltage exceeds the voltage proportional to the press stroke. Since this is sometimes detected as an overrun, abnormalities in clutches, brakes, etc. can be easily discovered.

Also, when the number of press strokes is small, a small
Since overruns are detected using angles and when the number of press strokes is large, overruns are detected using large angles, this eliminates malfunctions due to variations in the number of press strokes and enables highly accurate overrun detection. Become.

[Brief explanation of drawings]

The drawings show an embodiment of this invention, and FIG. 1 is a block diagram, and FIG. 2 is a diagram showing the relationship between the number of press strokes and the sliding angle. 5 is a D/A converter, 6 is a rotation detector, and I is a comparator.

Claims (1)

[Scope of utility model registration request] The rotation of the driving electric motor is transmitted to the main rotor via a flywheel and a clutch, and the pulse generator 1 provided on the main shaft is pressed to a variable speed press that moves the slide up and down via a crank provided on the main shaft. , a detector 2 that detects clutch "off" and brake "on"; a counter 4 that counts pulse signals from the pulse generator 1 only when a signal is input from the detector 2; A D/A converter 5 converts the count value into a voltage a, and a voltage a is output from the D/A converter 5, which is proportional to the number of strokes and when the number of strokes is small, from the rotation speed of the flywheel. A rotation detector 6 that generates a voltage such that the difference between the D and D is small and the difference increases as the stroke number increases;
The voltage asb output from the A converter 5 is compared, and the voltage a
Rinalpress's overrun detection device includes a comparator 7 that outputs an overrun signal when the voltage exceeds the voltage γ, and a relay circuit 8 that operates based on the overrun signal from the comparator γ to detect an overrun.