JPH02184702A - Position detecting device - Google Patents

Abstract

PURPOSE:To detect a specified position in the action width of a moving substance with one pilot lamp by lighting or flickering the pilot lamp when a magnetic field detection signal outputted from a magnetic sensor is equal to or exceeding 1st or 2nd threshold. CONSTITUTION:When a piston 21 to which a permanent magnet 22 is attached is within the action width B2 by taking the central position P1 of the position detecting device 1 as a center, a comparator 14 outputs a detection signal S4 because an output signal S2 (detection signal S1) is larger than threshold voltage V2. At such a time, a flickering oscillation circuit 15 outputs a flickering signal S5 and a transistor 17 periodically repeats being on/off, then an LED 18 flickers. When the piston 21 is within the action width B1(<B2), the comparator 13 outputs the detection signal S3 because the output signal S2 is larger than the threshold voltage V1. As a result, a transistor 16 is turned on and the LED 18 is lighted. In the case that the piston 21 is out of the width B2, the LED 18 is neither flickered nor lighted because the detection signals S3 and S4 are not outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position detection device for detecting the stroke position of a piston in a fluid pressure cylinder.

[Prior Art] Conventionally, single body pressure cylinders such as hydraulic cylinders and pneumatic cylinders have been equipped with position detection devices for detecting the stroke position of their pistons.

In conventional position detection devices, a magnetic sensor attached to the outer circumferential surface of the cylinder tube outputs a detection signal according to the strength of the magnetic field due to the magnetic field of a permanent magnet attached to the piston. In addition to outputting a detection signal when the detection signal is greater than or equal to the threshold value, it is configured to turn on an indicator light while the detection signal is being output in order to visually confirm that the detection signal is being output. ing.

Detection number 4 has a certain width (operation width) for the distance in the stroke direction of the piston, and while the piston is within this operation width, the detection signal is output and the indicator light is also lit. becomes. Therefore, even if the indicator light is on, it is impossible to know where the piston is within its operating range.

For this purpose, two magnetic sensors with different operating ranges and two indicator lights are provided, one of which lights up when the piston enters the operating range, and the other one lights up when the piston enters the operating range. A position detection device has been proposed in which the indicator light is turned on when the piston is located at the center of its operating range.

[Problem to be solved by the invention]

However, the above-mentioned conventional position detection device requires two magnetic sensors and two indicator lights, which increases the number of parts and complicates the circuit, resulting in an increase in the manufacturing cost of the position detection device.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a position detection device that can detect a specific position within the operating range even if there is only one magnetic sensor and one indicator light.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a position detection device for detecting the position of a moving object using the magnetic field of a permanent magnet provided on the moving object. a magnetic sensor that outputs a detection signal according to the strength of the magnetic sensor; a first comparing means that outputs a first detection signal when the detection signal is equal to or greater than a first threshold;
lighting means for lighting the indicator light in response to a detection signal; second comparison means for outputting a second detection signal when the detection signal is equal to or higher than a second threshold; and lighting means for lighting the indicator light in response to the second detection signal; and blinking means for blinking.

[For production]

A magnetic sensor detects the magnetic field of a permanent magnet provided on a moving object and outputs a detection signal depending on the strength of the magnetic field.

The first comparison means and the second comparison means respectively compare the detection signal from the magnetic sensor with the first threshold value or the second threshold value, and when the detection signal is equal to or higher than the respective threshold value, the first detection signal or A second detection signal is output.

The lighting means lights up the indicator light in response to the first detection signal.

The flashing means flashes the indicator light in response to the second detection signal.

When lighting by the lighting means and blinking by the blinking means overlap, priority is given to the one corresponding to a specific position within the operating range.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an electric circuit of a position detection device 1 according to the present invention.

The position detection device 1 includes a magnetic sensor 11 that outputs a detection signal S1 according to the strength of the magnetic field, an amplifier 12 that amplifies the detection signal S1, and a comparison between the output signal S2 of the amplifier 12 and a first threshold voltage Vl, and outputs the result. When the signal S2 is large, the detection signal S
A comparator 13 that outputs 3, a comparator 14 that compares the output signal S2 and a second threshold voltage v2 smaller than the first threshold voltage ■1, and outputs a detection signal S4 when the output signal S2 is large, a detection signal S4 When any of the blinking oscillation circuit 15 that outputs a blinking signal S5 that periodically repeats on and off when is on, the transistor 16.17 that becomes conductive when the base input is on, and the transistor 16.17 becomes conductive. Light emitting diode 1 that lights up
It consists of 8 etc.

Among these, the comparator 14, the blinking oscillation circuit 15, and the transistor 17 are the detection circuit 2 corresponding to the operating width B2, which will be described later.
6 is a detection circuit 3 corresponding to the operating width B1.

Each of these parts is housed in a suitable housing, the magnetic sensor 11 is placed in the center of the housing, and the light emitting diode 1B has a lighting or blinking state that can be detected from the outside by i! It is installed so that it is easy to recognize.

Next, the operation of the position detection bag f1 configured as described above will be explained with reference to FIG. 2 as well.

FIG. 2 shows that the piston 21 to which the permanent magnet 22 is attached is positioned in the left-right direction (arrow M1) with respect to the position detection device 1.
FIG. 3 is a diagram showing the state of signals in each part when moving in a direction (direction).

When the piston 21 is at a position facing the position detection device 1, that is, at the center position P1 of the position detection device 1, the output signal S2 (detection signal Sl) is at a maximum, and the output signal S2 is at the center position P1.
The output signal S2 (detection signal Sl) decreases as it moves from left to right.

The piston 21 has a movement width B centered on the median value 1tP1.
2, the output signal S2 is larger than the second threshold voltage v2, so the comparator 14 outputs the detection signal S4. At this time, the blinking oscillation circuit 15 outputs a blinking signal S5, which causes the transistor 17 to repeatedly turn on and off periodically, causing the light emitting diode 18 to blink. This period is about a fraction of a second to several seconds.

The piston 21 has a movement width B1 centered on the center position P1.
If it is within the range, the output signal S2 is larger than the first threshold voltage Vl, so the comparator 13 outputs the detection signal S3. As a result, the transistor 16 turns on and the light emitting diode 18 lights up. At this time, the transistor 17 is repeatedly turned on and off periodically, but since both transistors 16 and 17 are connected in parallel, the light emitting diode 18 remains lit and does not blink.

When the piston 21 is outside the operating width B2, the detection signals S3 and 34 are not output, so the light emitting diode 18 does not blink or light up.

That is, when the light emitting diode 18 is blinking, the piston 21 is within the range of the operating width B2 of the position detection device 1, and the detection signal S4 is output, but not at the center of the operating width B2. When the light emitting diode 18 is lit, the piston 21 is within the operating width B1 of the position detection device 1, the detection signal S4 is output, and the operating width B2 is
It is confirmed that the detection signal S4 is stable.

According to the embodiment described above, there is only one magnetic sensor 11 and only one light emitting diode 18, but the piston 21
It is possible to know whether or not the position is within the motion width Bl of a specific position within the motion width B2. Therefore, position detection device 1
The number of parts required is small, the circuit becomes simple, and an increase in the manufacturing cost of the position detection device 1 is prevented. Confirmation is easy because there is only one light emitting diode 18 and it is only necessary to confirm whether it is blinking or lighting. Also, power consumption is reduced. By varying the first threshold voltage Vl or the second threshold voltage v2, the operating width Bl can be easily adjusted.

B2 can be variably adjusted. Further, unlike the case where a plurality of magnetic sensors are used, there is no variation in the position of the operating width B1 with respect to the operating width B2 due to variations in the characteristics of the plurality of magnetic sensors, and adjustment is easy.

In the above embodiment, the light emitting diode 18 lights up in the operating width Bl and blinks in the operating width B2, but conversely, the light emitting diode 18 blinks in the operating width Bl and lights up in the operating width B2. You can do it like this.

In the above embodiment, instead of the light emitting diode 18,
Amplifier 12, which may use a neon lamp or light bulb, etc.
may be omitted. In addition, the circuit configuration and the configuration of each part of the position detection device I can be made into various configurations other than those described above.

〔Effect of the invention〕

According to the present invention, the magnetic sensor and the indicator light each have one
However, it is possible to know whether it is at a specific position within the operating range. Therefore, the number of parts of the position detection device can be reduced, the circuit can be simplified, and an increase in the manufacturing cost of the position detection device can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an electric circuit of a position detection device according to the present invention, and FIG. 2 is a diagram showing signal states of each part. 1... Position detection device, 11... Magnetic sensor, 13
... Comparator (first comparing means), 14... Comparator (second comparing means), 15... Blinking oscillation circuit (blinking means), 16... Transistor (lighting means)
, 17... Transistor (flashing means), 18... Light emitting diode (indicator light), 21... Piston (moving object), 22... Permanent magnet, Sl... Detection signal, S2
...output signal (detection signal), S3...detection signal (first detection signal), S4...detection signal (second detection signal), vl...first threshold voltage (first threshold), ■2・
...Second threshold voltage (second threshold).

Claims (1)

[Claims] (1) A position detection device for detecting the position of a moving object using the magnetic field of a permanent magnet provided on the moving object, which detects the magnetic field of the permanent magnet and generates a detection signal according to the strength of the magnetic field. a magnetic sensor that outputs a magnetic sensor; a first comparison unit that outputs a first detection signal when the detection signal is equal to or higher than a first threshold; and a lighting unit that lights up an indicator lamp based on the first detection signal; a second comparison means for outputting a second detection signal when the detection signal is equal to or higher than a second threshold; and a blinking means for blinking the indicator light according to the second detection signal. Characteristic position detection device.