JP2979842B2 - Temperature sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensor used for detecting, for example, abnormal overheating of a current-carrying conductor of a power device or the like.

[0002]

2. Description of the Related Art Since a high voltage is applied to a current-carrying conductor of a power device and a large current flows, the conductor may be abnormally overheated. For this reason, a means is employed to detect abnormal overheating by attaching a thermo label to the conductor and observing a change in color from a distance, or to detect an abnormal overheating state of the conductor using a thermo camera. In addition, there are a thermocouple, a thermometer, and a thermistor for measuring the temperature of the conductor.

[0003]

As described above, in order to detect the abnormal overheating of the conductor of the power equipment as described above, the first is a thermo label and the second is a thermo camera, but the first thermo label is inexpensive. However, unless a method for detecting a color change is considered, there is a problem that monitoring cannot be performed at all times and also a problem that durability is poor.

Although the second thermo camera is expensive, it has a problem in long-term stability of the sensor portion. In addition, thermocouples, thermometers and thermistors have the problem that they cannot be directly attached to conductors due to their electrical insulation.These temperature sensors measure the temperature transmitted to gas and insulators, and therefore have low sensitivity. There is a problem, and the influence of other heat sources is great.

The present invention has been made in view of the above circumstances, and has as its object to provide a temperature sensor which is durable, can be directly attached to a conductor, and has high sensitivity.

[0006]

According to the present invention, in order to achieve the above object, first and second concave portions are formed at both ends in the axial direction so as to face the ferromagnetic state according to a temperature change. , A columnar temperature-sensitive magnetic body that changes to a paramagnetic state, a first permanent magnet fitted and adhered to a first recess of the temperature-sensitive magnetic body, and a second recess of the temperature-sensitive magnetic body A second permanent magnet fitted movably in the axial direction so that the magnetic pole facing the first permanent magnet has the same magnetic pole, and a lid attached to the opening end surface of the second recess. And an optical fiber penetrating through the lid and having an outer periphery adhered to the lid, and a light-emitting portion and a light-receiving portion separated by a light-shielding wall. The light emitting portion and the light receiving portion of the fiber are reflected and shielded.

Further, according to the present invention, a first fine hole communicating with the first and second concave portions in the axial direction and a second fine hole communicating with the first fine hole are formed in the first permanent magnet. And inserting a rod for checking the operation of the second permanent magnet into the first and second pores,
The second permanent magnet is moved.

[0008]

When the temperature-sensitive magnetic material is lower than the operating temperature, it is in a ferromagnetic state and does not affect the magnetic forces of the first and second permanent magnets. For this reason, since the second permanent magnet does not move, the light emitting part and the light receiving part of the optical fiber are not shielded from light. However, when the temperature-sensitive magnetic material becomes higher than the operating temperature, the magnetic forces of the first and second permanent magnets affect each other, and the second permanent magnet receives the repulsive force of the first permanent magnet. It moves and closes the light emitting part and the light receiving part of the optical fiber.

[0009] To ensure that the second permanent magnet operates, a rod for confirming the operation is inserted into the first and second pores, and the second permanent magnet is moved.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. 1 to 3, reference numeral 10 denotes a temperature sensor,
This temperature sensor 10 is configured as follows. 11
Are first and second concave portions 12 and 13 from both ends in the axial direction.
Is a columnar temperature-sensitive magnetic body having a perforated hole.
1 is composed of M _n -Z _n system Souto ferrite. The first concave portion 12 of the temperature-sensitive magnetic body 11 has a cylindrical first
The permanent magnets 14 are fitted and adhered, for example, in the direction of the magnetic poles shown. Reference numeral 15 denotes a temperature-sensitive magnetic bottom cover adhered to the illustrated bottom end surface of the temperature-sensitive magnetic body 11.

A non-magnetic pipe 16 is fitted into and adhered to the second recess 13 of the temperature-sensitive magnetic body 11. A second permanent magnet 17 is fitted into the pipe 16. At this time, the lower magnetic pole of the second permanent magnet 17 is
The first permanent magnet 14 is fitted so as to have the same polarity as the upper magnetic pole. Numeral 18 denotes a non-magnetic upper lid adhered to the upper end surface of the temperature-sensitive magnetic body 11 as shown in FIG.
Is passed through the optical fiber 19 and the outer periphery thereof is adhered to the upper lid 18. The optical fiber 19 is a light emitting portion 19a
And a light receiving portion 19b. Both portions 19a and 19b are partitioned by a light shielding wall 19c. Reference numeral 20 denotes a reflection plate, which is bonded when the reflection efficiency of the upper surface of the second permanent magnet 17 is low. FIG. 2B is a characteristic curve diagram of the amount of reflected light with respect to the distance between the upper surface of the second permanent magnet 17 and the end surface of the optical fiber 19.

FIG. 2B shows the light emitting portion 19a of the optical fiber 19.
Is reflected on the upper surface of the second permanent magnet 17 (or the reflecting plate 20 if there is a reflecting plate 20) and is incident on the light receiving portion 19b, and the reflected light that the second permanent magnet 17 moves gradually decreases. When the second permanent magnet 17 abuts on the end face of the optical fiber 19, light from the light emitting section 19a is blocked.

Since the second permanent magnet 17 shows a ferromagnetic state when the temperature-sensitive magnetic material 11 is lower than the Curie temperature (operating temperature), it does not move from the position shown in FIG. 2A. Since the magnetic body 11 is in a paramagnetic state, the first and second permanent magnets 14 and 17 are magnetically repulsive, and the second permanent magnet 17 moves upward in the drawing to shield the end face of the optical fiber 19 from light.

FIG. 4 shows that the second permanent magnet 1 is
FIG. 4 is a characteristic diagram showing a state in which a force acting on the second permanent magnet 17 at a position where the first permanent magnet 7 contacts (when the stroke X = 0) changes with temperature. In FIG.
_S (attraction force component: second permanent magnet 17 and temperature-sensitive magnetic substance 11
) And F _R (repulsive force component: the force of the magnetic force of the first permanent magnet 14 acting on the second permanent magnet 17). Curie temperature (operating temperature) of the temperature-sensitive magnetic body 11
The change in the acting force at is greater than when only F _S (or F _R ). FIG. 5 is a measured data characteristic diagram showing a change in the resultant force F with respect to the temperature.

FIGS. 6A and 6B and FIGS. 7A and 7B show magnetic field lines from the first and second permanent magnets 14 and 17 when the temperature-sensitive magnetic material 11 changes from a ferromagnetic state to a paramagnetic state depending on temperature. FIG. 6A shows the state of the lines of magnetic force when the temperature-sensitive magnetic body 11 is at or below the Curie temperature.
A shows the state of the lines of magnetic force when the temperature-sensitive magnetic body 11 is at or above the Curie temperature. It can be seen from FIG. 7A that when the temperature is equal to or higher than the Curie temperature, the lines of magnetic force spread and the repulsive force increases as shown in the figure. FIGS. 6B and 7B are characteristic diagrams showing the relationship between the combined force F acting on the second permanent magnet 17, the repulsive force F _R , and the attractive force F _S.

FIG. 8 is a characteristic diagram showing a force relationship between the temperature-sensitive magnetic material and the second permanent magnet. FIG. 8 shows the relationship between the temperature-sensitive magnetic material at room temperature, about 90 ° C., and 100 ° C. It is data obtained by actually measuring what kind of force acts on the second permanent magnet at a temperature of ° C. For this measurement, a temperature-sensitive magnetic body 11a and first and second permanent magnets 14a and 17a as shown in FIG. 9 were used. In FIG. 9, the second permanent magnet 14a is a temperature-sensitive magnetic material.
11 buried in the second recess 13 depending on the operating temperature of 11,
Some protrude .

FIG. 10 is a longitudinal sectional view showing another embodiment of the present invention. In this embodiment, a first fine portion which connects the first and second concave portions 12 and 13 of the temperature-sensitive magnetic body 11 in the axial direction is provided. A hole 21 and an axial direction of the first permanent magnet 14
And a third pore 23 formed in the axial direction of the bottom lid 15 of the temperature-sensitive magnetic body and communicating with the second pore 22. It is a thing. By providing the first to third pores 21 to 23 in this manner, a thin push rod 24 is inserted into the pores 21 to 23 from below in the figure, and the bottom of the second permanent magnet 17 is Push up. Thus, the amount of reflected light incident on the light receiving portion 19b from the light emitting portion 19a of the optical fiber 19 changes with the rise of the second permanent magnet 17, so that the operation of the temperature sensor can be confirmed.

[0018]

As described above, according to the present invention,
An external magnetic field acts on the second permanent magnet, causing the operating temperature to fluctuate.
And the second permanent magnet should be
2 so that the external magnetic field is
Hardly act on the permanent magnets of the
When the first permanent magnet is surrounded by a temperature- sensitive magnetic material , the change in repulsion force due to temperature can be increased,
As a result, the change in the force acting on the second permanent magnet near the operating temperature (Curie temperature) of the temperature-sensitive magnetic body increases.
In addition to this, there is an advantage that the operation of transmitting and blocking light rays can be performed stably and the durability can be improved, and the light can be directly attached to a conductor.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

2A is a longitudinal sectional view of the embodiment, and FIG. 2B is a characteristic diagram of the amount of reflected light with respect to the position of a second permanent magnet.

FIG. 3 is a top view of FIG. 2A.

FIG. 4 is a characteristic diagram showing a change in a force F acting on a second permanent magnet depending on a temperature.

FIG. 5 is a graph showing a change characteristic of a temperature-sensitive magnetic body depending on a temperature of a force acting on a second permanent magnet.

6A is an explanatory diagram showing a distribution state of magnetic lines of force generated in the first and second permanent magnets when the temperature is equal to or lower than the Curie temperature, FIG.
Is a characteristic diagram of the resultant force.

FIG. 7A is an explanatory diagram showing a distribution state of lines of magnetic force generated in the first and second permanent magnets when the temperature is equal to or higher than the Curie temperature, and FIG.
Is a characteristic diagram of the resultant force.

FIG. 8 is a characteristic diagram of a temperature acting on a temperature-sensitive magnetic body and a force acting between a second permanent magnet.

FIG. 9 is a configuration explanatory view of an embodiment used for measuring the data of FIG. 8;

FIG. 10 is a longitudinal sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Temperature-sensitive magnetic body 12 ... 1st recess 13 ... 2nd recess 14 ... 1st permanent magnet 16 ... Non-magnetic pipe 17 ... 2nd permanent magnet 18 ... Non-magnetic upper lid 19 ... Optical fiber

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01K 7/36

Claims (3)

(57) [Claims] 1. A temperature- sensitive magnetic body having first and second concave portions formed at both ends in the axial direction facing in the axial direction and changing from a ferromagnetic state to a paramagnetic state according to a temperature change. A first permanent fit into the first recess of the magnetic body;
The magnet and the second concave portion of the temperature-sensitive magnetic body are movable in the axial direction.
And the magnetic pole facing the first permanent magnet is the same magnetic pole
And a second permanent magnet, wherein the second permanent magnet is at or above the operating temperature of the temperature-sensitive magnetic material.
Moving from the second recess toward the outside in the axial direction.
A part protrudes from the second recess, and when the temperature falls below the operating temperature, the second
Move inward in the axial direction of the second concave portion to form the second concave portion
A temperature sensor characterized by being buried . 2. The method according to claim 2, further comprising:
The operating state of the permanent magnets is optically detected.
The temperature sensor according to claim 1, wherein: 3. A first communication device which communicates the first and second recesses in the axial direction.
The first pore and the second pore communicating with the first pore are
1 permanent magnet, and a second permanent magnet in the first and second pores.
Insert the rod for confirming the operation of the magnet and insert the second permanent magnet
2. The method according to claim 1, wherein
2. The temperature sensor according to 2 .