JP2979843B2 - 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 an object of the present invention is to provide a temperature sensor that can reduce malfunction due to a temperature change, is durable, and can be directly attached to a conductor. I do.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is connected in the axial direction, and changes from a ferromagnetic state to a paramagnetic state according to a temperature change, and has different Curie temperatures. A first and a second temperature-sensitive magnetic body, a concave portion formed in an axial direction from an end face of the first temperature-sensitive magnetic body, and an axial direction from an end face of the second temperature-sensitive magnetic body. The formed hole, the first permanent magnet fitted and adhered to the recess, and the magnetic pole that is movably fitted in the hole in the axial direction and faces the first permanent magnet have the same magnetic pole. A second permanent magnet, a lid attached to the opening end face of the hole, a penetrating penetrating lid, and an outer periphery adhered to the lid. And a divided optical fiber.

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]

The first and second temperature-sensitive magnetic materials have different Curie temperatures, and therefore have different temperature ranges from the paramagnetic state to the ferromagnetic state and from the ferromagnetic state to the paramagnetic state. That is, a temperature difference (hysteresis) occurs between the operating temperature and the return temperature of the first and second temperature-sensitive magnetic bodies. For this reason, the range in which the magnetic forces of the first and second permanent magnets affect each other increases or decreases according to the Curie temperatures of the first and second temperature-sensitive magnetic bodies. As a result, the range of the second permanent magnet affected by the repulsive force of the first permanent magnet changes, and the light emitting unit and the light receiving unit of the optical fiber are closed.

[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]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 to 3, reference numeral 10 denotes a temperature sensor, and the temperature sensor 10 is configured as follows. Reference numeral 11 denotes a temperature-sensitive magnetic body. The temperature-sensitive magnetic body 11 connects a first temperature-sensitive magnetic body 11a formed in a columnar shape and a second temperature-sensitive magnetic body 11b formed in a cylindrical shape as shown in the figure. It is composed. The first and second temperature-sensitive magnetic bodies 11a and 11b are formed of materials having different temperatures at which the ferromagnetic state changes to the paramagnetic state, that is, different Curie temperatures. Reference numeral 12 denotes a recess formed in the first temperature-sensitive magnetic body 11a in the axial direction from the illustrated bottom surface, and a columnar first permanent magnet 13 is fitted into the recess 12 in the direction of the illustrated magnetic pole, for example. Glued. Reference numeral 14 denotes a bottom cover made of a temperature-sensitive magnetic material adhered to the illustrated bottom end surface of the first temperature-sensitive magnetic material 11a.

A pipe 16 made of a non-magnetic material is fitted into the hole 15 of the second temperature-sensitive magnetic body 11b, and this is adhered to the inner peripheral wall of the hole 15. A cylindrical second permanent magnet 17 is fitted into the pipe 16. At this time, the lower magnetic pole of the second permanent magnet 17 is positioned at the upper part of the first permanent magnet 13 as shown in the figure. It is fitted so that it has the same polarity as the magnetic pole. Reference numeral 18 denotes a non-magnetic upper cover adhered to the upper end surface of the second temperature-sensitive magnetic body 11b in the drawing.
The optical fiber 19 having the configuration shown in FIGS. 2 and 3 is made to pass through, and the outer periphery thereof is adhered to the upper lid 18. Optical fiber 19
Is composed of a light emitting portion 19a and a light receiving portion 19b.
Reference numeral 19b is defined 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. When the second permanent magnet 17 moves, the reflected light 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.

Next, the operation of the embodiment configured as described above will be described. In this embodiment, since the first and second temperature-sensitive magnetic bodies 11a and 11b having different Curie temperatures are used for the temperature-sensitive magnetic body 11, the temperature-sensitive magnetic body 11 is the first and second temperature-sensitive magnetic bodies 11a. , 11b, two on (operating temperature) and off (return temperature) determination results are obtained as shown in FIG.

First, when the Curie temperature condition is the first temperature-sensitive magnetic material 11a <the second temperature-sensitive magnetic material 11b, the operating temperature is T _1H shown in FIG. 4 and the return temperature is T _1L shown in FIG. In addition, the temperature difference (hysteresis) for the on / off operation can be increased.

Second, when the Curie temperature condition is the first temperature-sensitive magnetic body 11a> the second temperature-sensitive magnetic body 11b, the operating temperature is T _2H shown in FIG. 4 and the return temperature is T _2L shown in FIG. , The temperature difference is smaller than in the first case.

FIG. 4 shows an operating temperature T _0H and a return temperature T _0L when a temperature-sensitive magnetic material having one Curie temperature is used.
The temperature difference (hysteresis) is also shown.

As described above, the first and second Curie temperatures are different.
The temperature-sensitive magnetic material 1 is formed by using the second temperature-sensitive magnetic materials 11a and 11b.
When 1 is configured, a configuration in which the hysteresis between the operating temperature and the return temperature of the temperature sensor 10 is changed can be configured, and a temperature sensor according to the application can be obtained. As described above, in the temperature-sensitive magnetic body 11 of this embodiment, the Curie temperature (operating temperature: T _1H , T _{2H in} FIG. 4)
In the following cases, the first and second temperature-sensitive magnetic bodies 11a and 11b
Both show a ferromagnetic state, and the second permanent magnet 17 does not move from the position of FIG. 2A. When the temperature is equal to or higher than the Curie temperature, the temperature-sensitive magnetic body 11 is in a paramagnetic state (the value that exceeds the Curie temperature differs depending on the first and second cases).
Therefore, the first and second permanent magnets 14 and 17 are magnetically repulsive, and the second permanent magnet 17 moves upward in the figure to shield the end face of the optical fiber 19 from light.

FIG. 5 shows first and second temperature-sensitive magnetic bodies 11a and 11a.
FIG. 13 is a characteristic diagram showing a state in which a force acting on the second permanent magnet 17 at a position where the second permanent magnet 17 is in contact with the connecting portion 1b (when the stroke X = 0) changes with temperature.
In FIG. 5, the resultant force F is F _S (attractive force component: by the second permanent magnet 17 and the temperature-sensitive magnetic body 11) and F _R (repulsive force component: the magnetic force of the first permanent magnet 13 is the second permanent magnet). (Force acting on the magnet 17). The change of the acting force at the Curie temperature (operating temperature) of the first and second temperature-sensitive magnetic bodies 11a and 11b is larger than that at the time of only F _S (or F _R ). FIG. 6 is a measured data characteristic diagram showing a change in the resultant force F with respect to the temperature.

FIGS. 7A and 7B and FIGS. 8A and 8B show first and second permanent magnets when the first and second temperature-sensitive magnetic bodies 11a and 11b change from a ferromagnetic state to a paramagnetic state depending on temperature. FIG. 7A shows the state of the lines of magnetic force from 13, 13;
FIG. 8A shows the state of the lines of magnetic force when the first and second temperature-sensitive magnetic bodies 11a and 11b are at or below the Curie temperature, and FIG. 8A shows that the first and second temperature-sensitive magnetic bodies 11a and 11b are at or above the Curie temperature. The state of the magnetic field lines at the time is shown. From FIG. 8A, it can be seen 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. 7B and 8B are characteristic diagrams showing the relationship between the resultant force F acting on the second permanent magnet 17, the repulsive force F _R , and the attractive force F _S.

FIG. 9 shows a temperature-sensitive magnetic body 11 and a second permanent magnet 1.
FIG. 9 is a characteristic diagram showing a force relationship acting between the temperature-sensitive magnetic material at room temperature, around 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. In this measurement, the temperature-sensitive magnetic body 111 and the first and second permanent magnets 13a and 17 as shown in FIG.
a was used.

FIG. 11 is a longitudinal sectional view showing another embodiment of the present invention. In this embodiment, a concave portion 1 of a first temperature-sensitive magnetic body 11a is shown.
A first fine hole 21 axially communicating the hole 2 of the second temperature-sensitive magnetic body 11b with the hole 15 of the second temperature-sensitive magnetic body 11b; The second pores 22 to be in communication with each other and the bottom cover 15 of the temperature-sensitive magnetic body are formed in the axial direction,
It is composed of the second pores 22 and the third pores 23 that are in communication with each other. Thus, the first to third pores 2
By providing 1 to 23, a thin push rod 24 is inserted into the small holes 21 to 23 from below in the figure, and the bottom of the second permanent magnet 17 is pushed up by the push rod 24. 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.

[0022]

As described above, according to the present invention,
The temperature difference (hysteresis) between the operating temperature and the return temperature can be changed by connecting two types of temperature-sensitive magnetic materials having different Curie temperatures, thereby preventing a malfunction due to a change in temperature in the state of light transmission and light shielding. Can be smaller,
In addition, there are advantages that there is durability and that it can be directly attached to a conductor.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing one 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 an explanatory diagram of the operation of the temperature sensor of the embodiment according to the present invention.

FIG. 5 is a characteristic diagram showing a change in a force F acting on a second permanent magnet depending on a temperature.

FIG. 6 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.

7A 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. 8A 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. 9 is a characteristic diagram of a temperature acting on a temperature-sensitive magnetic body and a force acting between a second permanent magnet.

FIG. 10 is a configuration explanatory view of an embodiment used for measuring the data of FIG. 9;

FIG. 11 is a longitudinal sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Temperature-sensitive magnetic body 11a ... 1st temperature-sensitive magnetic body 11b ... 2nd temperature-sensitive magnetic body 12 ... recessed part 13 ... 1st permanent magnet 15 ... Hole 16 ... Non-magnetic pipe 17 ... 2nd Permanent magnet 18 ... Non-magnetic upper cover 19 ... Optical fiber

Claims (2)

(57) [Claims] A first temperature-sensitive magnetic body which is connected in the axial direction, changes from a ferromagnetic state to a paramagnetic state in accordance with a temperature change, and has different Curie temperatures, respectively; A recess formed in the axial direction from the end face of the temperature-sensitive magnetic body, a hole formed in the axial direction from the end face of the second temperature-sensitive magnetic body, and fitted into and bonded to the recess. A first permanent magnet, movably fitted in the hole in the axial direction,
A second permanent magnet having the same magnetic pole as that of the permanent magnet, a lid attached to the opening end surface of the hole, and a perimeter adhered to the lid while penetrating the lid. A temperature sensor comprising: a light emitting unit and an optical fiber in which a light receiving unit is partitioned by a light shielding wall. 2. 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, The temperature sensor according to claim 1, wherein a rod for confirming the operation of the second permanent magnet is inserted into the first and second pores to move the second permanent magnet.