JPH08304007A - Magnetic-substance detection apparatus - Google Patents

Abstract

PURPOSE: To miniaturize a magnetic-substance detection apparatus which detects whether a magnetic substance as a member to be detected exists or not in a detection position inside a nonmagnetic substance irrespective of whether a product is large or small. CONSTITUTION: A magnetic 12 of which magnetic path changes depending on whether a magnetic substance exists or not is provided inside a case 11, and a magnetic sensor 15 is provided in a position which can detect a change in the magnetic path. Then, e.g. when the operation of a gas meter is to be detected, a detection face 10a is put to a position corresponding to an iron film plate 30 on a nonmagnetic-substance-film lid 20. Thereby, when the film plate 30 is away from the detection face 10a, a magnetic path which mostly passes the magnetic sensor 15 is formed, magnetism which is comparatively strong is sensed by the magnetic sensor 15, and it is detected that the film plate 30 does not exists in a prescribed detection position. On the other hand, when the film plate 30 is brought close to the detection face 10a, a magnetic path which hardly passes the magnetic sensor 15 is formed, magnetism which is comparatively weak is sensed by the magnetic sensor 15, and it is detected that the film plate 30 exists in the prescribed detection position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic substance detecting device used, for example, for operating a diaphragm of a gas meter or for inspecting the presence or absence of a steel core in an electric wire.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, for example, as shown in FIG. 8, a magnetic body detecting device of this type is provided with a magnet 2 at one end 1a of a device body 1 having a substantially Y shape, and a magnet 2 serving as an N pole. There is a configuration in which the magnetic sensor 3 is provided on the other end 1b facing each other (see Japanese Utility Model Laid-Open No. 4-85591).

When the magnetic substance detecting device is used, it holds the handle portion 1c of the main body 1 of the device and the tip portion 1
An electric wire 4 is inserted as a product between a and 1b, and the apparatus body 1 is moved in the length direction of the electric wire 4. Then, at the time of the movement, the magnetic sensor 3 detects the strength of the magnetic force that changes between the N pole of the magnet 2 and the magnetic sensor 3, and as a result, the steel in the outer peripheral coating portion (nonmagnetic body) 4a is detected. It is detected whether or not there is a core (magnetic material) 4b. Then, based on the detection result of the magnetic sensor 3, the CPU (not shown) determines whether or not there is a disconnection and displays it on the display unit.

[0004]

However, in such a conventional magnetic body detection device, in order to detect the presence or absence of the magnetic body 4b according to the change in the strength of the magnetic force between the magnet 2 and the magnetic sensor 3, It is necessary to provide the space 5 between the magnet 2 and the magnetic sensor 3 according to the size of the product to be inserted, and there is a problem that the device becomes large accordingly.

Therefore, it is an object of the present invention to realize miniaturization of the above magnetic substance detecting device regardless of the size of the product.

[0006]

Therefore, the present invention provides
For example, as shown in the illustrated embodiment below, a film plate 30 is placed at a detection position in a non-magnetic body such as a film lid (main body shell) 20.
In the magnetic body detection device 10 for detecting whether or not there is a magnetic body that is a member to be detected, such as the magnet 12, the magnetic path M changes between when the magnetic body is present at the detection position and when the magnetic body is not present. A magnetic sensor 15 provided at a position capable of detecting a change in the magnetic path M of the magnet 12 is provided.

According to a second aspect of the present invention, for example, as shown in the following illustrated embodiment, in the magnetic substance detecting device 10 according to the first aspect, the magnet 12 is provided with a magnetic concentrating portion 12b, and the magnetic concentration thereof is provided. The magnet 12 is arranged so that the portion 12b faces the magnetic sensor 15.

According to a third aspect of the present invention, for example, as shown in the following illustrated embodiment, in the magnetic substance detection device 10 according to the first aspect, the N pole 12a and the S pole 1 of the magnet 12 are provided.
The magnetic sensor 15 is provided so as to be sandwiched between 2c.

[0009]

In the present invention, the change in the magnetic path M of the magnet 12 is detected by the magnetic sensor 15 to detect the presence / absence of the magnetic body which is the member to be detected.

According to the second aspect, when there is no magnetic substance at the detection position in the non-magnetic substance, the magnetic flux density from around the N pole of the magnet 12 toward the magnetic sensor 15 is increased.

According to the third aspect, most of the magnetism from the N pole 12a of the magnet 12 passes through the magnetic sensor 15 and the S pole 12c when there is no magnetic body at the detection position in the nonmagnetic body.
A magnetic path toward the side is formed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a magnetic substance detection device according to the present invention used for a gas meter as an example.

Reference numeral 10 in the figure denotes the magnetic substance detecting device. The magnetic body detection device 10 includes a magnet 12 in a box-shaped case 11. A permanent magnet is used as the magnet 12.
Also, an electromagnet can be used.

Further, the magnetic substance detecting device 10 includes a magnet 12
As shown in FIG. 2, a magnetic sensor 15 composed of, for example, a magnetoresistive element is provided on the lower side of the N pole 12a in FIG. 1 and at a position overlapping the magnetic path M of the magnet 12 formed in a natural state. .

By the way, reference numeral A in FIG. 1 denotes a measuring portion of a gas meter to be inspected by using this magnetic substance detecting device 10, reference numeral 19 denotes a main body case in the measuring portion A shown in FIG. 3, and reference numeral 20. Is a film lid made of a non-magnetic material that covers the body case 19.

The gas meter has, for example, as shown in FIG. 3, a metering section A, a motion converting section B on the upper side in the figure,
It is composed of a display portion C on the left side thereof. Then, the measuring unit A
In the body case 19, the two chambers 16 and 16 are partitioned by the diaphragm 18, and each chamber has a pair of measuring chambers 1.
6a and 16b are formed. The diaphragm 18 is provided with an iron membrane plate 30 attached to each central portion thereof, and is supported in each chamber 16 so as to be capable of reciprocating left and right in the drawing.

In the gas meter, during metering, the gas flowing in from the gas inlet 21 is introduced into one of the pair of metering chambers 16a and 16b through the motion converting section B, and the gas in the other metering chamber is pushed out. It is discharged from the outlet 22 in a fixed amount. At that time, the diaphragm 18 is reciprocated, the movement is converted into a rotary motion by the motion conversion unit B, and the rotary motion is transmitted to the display unit via the transmission mechanism, and the gas flow rate is integrated and displayed there.

Now, a case where the above-described magnetic substance detecting device 10 is used to inspect the movement of the diaphragm 18 of the gas meter will be described below.

In that case, the gas meter is fixed appropriately and operated on a trial basis. On the other hand, holding the magnetic substance detection device 10, as shown in FIG. 1, the detection surface 10 a is applied to the film lid 20 at a position corresponding to the film plate 30. Then, a start switch (not shown) is pressed to start detection.

However, if the film plate 30 is used as the detection surface 10a,
When it is distant as shown in FIG. 4, a magnetic path M is formed as shown by an arrow. That is, the magnetic path M, which mostly passes through the magnetic sensor 15, is formed. Therefore, a relatively strong magnetism is detected by the magnetic sensor 15, and the film plate 30 is now detected on the detection surface 10a.
It is detected that it is not at a predetermined detection position close to.

On the contrary, when the film plate 30 approaches the detection surface 10a, a magnetic path M as shown by an arrow in FIG. 5 is formed.
That is, the magnetic path M that hardly passes through the magnetic sensor 15 is formed. Therefore, the relatively weak magnetism is applied to the magnetic sensor 1.
5, and it is detected that the membrane plate 30 is now at the predetermined detection position. Then, based on the detection result of the magnetic sensor 15, the CPU (not shown) determines that the diaphragm 18 is operating, and displays that fact on the display means (not shown).

By the way, in the above-described embodiment, the magnet 12 is formed so that the cross-sectional shape becomes a polygonal shape (a triangular shape is good) like the quadrangular shape shown in FIG. 6, and one corner thereof is on the magnetic sensor 15 side. It should be placed toward. Then, the magnetic concentrated portion 12b is formed on the N pole 12a side of the one corner portion.

Therefore, in this case, when the film plate 30 is not at the detection position as shown in FIG. 4, the magnetic path M in which the magnetism concentrates from the magnetic concentrating portion 12b toward the magnetic sensor 15 is formed. That is, the magnetic flux density toward the magnetic sensor 15 from around the N pole 12a of the magnet 12 is increased. Therefore, the magnetic sensor 15 senses stronger magnetism as compared with the magnetism sensed when the film plate 30 is at the detection position as shown in FIG. Therefore, there is a large difference in the magnetic strength sensed when the film plate 30 is at the detection position and when it is not, and thus the magnetic sensor 15 can reliably change the magnetic path that changes depending on the position of the film plate 30. Can be detected.

Further, in the magnetic substance detecting device 10 of the present invention, as shown in FIG. 7, for example, the magnet 12 is formed in a substantially U shape, and is sandwiched between the N pole 12a and the S pole 12c of the magnet 12, The magnetic sensor 15 may be provided.

In this case, when the film plate 30 is not in the detection position as shown by the solid line in FIG. 7, a magnetic path is formed in which most of the magnetism from the N pole 12a goes through the magnetic sensor 15 to the S pole 12c. Therefore, the magnet 12 has a magnetic concentration portion 12
Even when compared with the case of FIG. 6 in which b is provided, the magnetic sensor 15 detects even stronger magnetism. Thereby, the membrane plate 30
The magnetic sensor 15 can more reliably detect the change in the magnetic path that changes depending on the position.

In the illustrated embodiment described above, the magnetic substance detection device 10 is used to detect whether or not the iron film plate 30 of the gas meter is operating. However, the present invention can also be used when detecting whether or not a magnetic substance is present, or whether or not it is at a predetermined position. Further, it is not limited to the case of detecting a magnetic body housed in a non-magnetic body such as the film lid 20, but also a case of detecting a magnetic body such as a steel core covered with a non-magnetic body covering portion such as an electric wire. Can also be used for.

[0027]

As described above, according to the present invention, in the magnetic body detection device, a magnetic path change can be detected at a position where the magnetic body of the member to be detected is at the detection position and when it is not.
Since the configuration is such that the magnetic sensor is arranged, the problem of increasing the size of the device due to the conventional arrangement of the product of the detected member between the magnet and the magnetic sensor is solved, which allows the device to be used regardless of the size of the product. It is possible to realize the miniaturization of.

According to the second aspect of the present invention, the magnet is provided with the magnetic concentrating portion, and the magnet is arranged with the magnetic concentrating portion facing the magnetic sensor. Therefore, when the magnetic body is not at the detection position, By increasing the magnetic flux density from around the N pole toward the magnetic sensor, this causes a large difference in the magnetic strength sensed when the magnetic body is at the detection position and when it is not. It is possible to reliably detect the change in the magnetic path that changes according to the magnetic sensor to accurately detect whether or not there is a magnetic body at the detection position in the non-magnetic body.

According to the third aspect, the N of the magnet is
Since the magnetic sensor is provided between the pole and the S pole, when the magnetic body is not at the detection position, most of the magnetism from the N pole passes through the magnetic sensor to the S pole, so that the magnetic body is at the detection position. There is a greater difference in the strength of the magnetic field that is sensed at certain times, which allows the magnetic sensor to more reliably detect changes in the magnetic path that change depending on the position of the magnetic body, and It is possible to accurately detect whether or not there is a magnetic substance at the detection position of.

[Brief description of drawings]

FIG. 1 shows a magnetic substance detection device according to an embodiment of the present invention,
It is a schematic block diagram shown in the state applied to the gas meter.

FIG. 2 is an explanatory diagram of a magnetic path in a natural state of a magnet included in the magnetic body detection device.

FIG. 3 is a side view showing the gas meter with a part thereof cut away.

FIG. 4 is an explanatory diagram showing a magnetic path when the film plate moves away from a detection position.

FIG. 5 is an explanatory diagram showing a magnetic path when the film plate is at a detection position.

FIG. 6 is an explanatory view showing an example in which a magnet is provided with a magnetic concentrating portion and is arranged so as to face a magnetic sensor.

FIG. 7 is a schematic configuration diagram showing an example in which a magnetic sensor is installed between the north and south poles of a magnet to detect a film plate.

FIG. 8 is a schematic configuration diagram showing a conventional magnetic material detection device with a part thereof cut away.

[Explanation of symbols]

 10 Magnetic Material Detection Device 12 Magnet 12a N Pole 12b Magnetic Concentration Part 12c S Pole 15 Magnetic Sensor 20 Membrane Lid (Non-Magnetic Body) 30 Membrane Plate (Magnetic Body) M Magnetic Path

Claims (3)

[Claims] 1. A magnetic body detecting device for detecting whether or not a magnetic body, which is a member to be detected, is present at a detection position in a non-magnetic body, and a magnetic path is formed when the magnetic body is present at the detection position and when it is not. A magnetic body detection device comprising a changing magnet and a magnetic sensor provided at a position capable of detecting a change in the magnetic path of the magnet. 2. The magnetic body detection device according to claim 1, wherein the magnet is provided with a magnetic concentration portion, and the magnet is arranged with the magnetic concentration portion facing the magnetic sensor. 3. The magnetic body detection device according to claim 1, wherein the magnetic sensor is provided so as to be sandwiched between the N pole and the S pole of the magnet.