JP3275557B2 - Temperature detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical temperature detection switch for detecting, as an optical signal, the arrival of a temperature of an object to be measured at a specific temperature.

[0002]

2. Description of the Related Art Using an electrically isolated temperature detecting means without being affected by electromagnetic induction or electrostatic induction,
A temperature detector that detects abnormal temperatures such as high-voltage cables and current bus bars, or the presence or absence of reaching a preset temperature, uses bimetal for the temperature detection means, and combines an optical fiber and a photoelectric remote measurement unit. Such an optical abnormal temperature detecting device is known from Japanese Patent Application Laid-Open No. 55-880021.

FIG. 7 shows the configuration of the temperature detecting device disclosed in the above publication, and the prior art will be described with reference to FIG.
In FIG. 7, reference numeral 20 denotes a temperature measuring object such as a high-voltage cable, 30 denotes a plate-shaped bimetal that is thermally conductively attached to the temperature measuring object 20 via a heat receiving plate 21, 10 denotes a light emitting optical fiber, and 11 denotes a light receiving member. And a light shielding plate 7 provided at the tip of the bimetal 30.
Are arranged so as to enter and exit an optical propagation path formed between the light emitting optical fiber 10 and the light receiving optical fiber 11.
Is composed.

The optical fibers 10 and 11 are connected to a light source 61 and a light receiving element 62 in a switch signal transmitting section 60, respectively. Reference numeral 63 denotes a switching circuit for transmitting, as an electric signal, whether or not the temperature reaches a preset temperature based on an output signal of the light receiving element 62. Reference numerals 81 and 82 denote light emitting optical fibers 10 and light receiving optical fibers. It is provided in the middle of 11,
The optical lenses are arranged so that the end faces of the respective optical fibers are located at the focal position, and convert the light flux between the lenses into parallel rays.

When the temperature of the temperature measuring object 20 rises in such a configuration, the plate-shaped bimetal 30 is bent and deformed from a solid line to a dashed line, and the light shielding plate 7 penetrates into the light propagation path of the optical switch 8 to form a parallel light beam. Part of the bundle is shielded from light. Thereby, a change in the temperature of the temperature measuring object 20 can be detected as a change in the amount of received light of the light receiving element 62. When the amount of received light exceeds a predetermined value, the output of the switching circuit is set to be inverted. By doing so, it is possible to provide a temperature switch for notifying that an abnormal temperature has been reached.

On the other hand, a temperature-sensitive ferrite whose magnetic permeability changes greatly on both sides of the Curie point, and as a result, the attractive force to the magnet changes rapidly before and after the Curie temperature as shown in FIG. Japanese Patent Application Laid-Open No. 47-105580 discloses a temperature detecting means as shown in FIG. 9 for detecting the arrival at the Curie temperature as an on / off signal of light.

In the temperature detecting means shown in FIG. 9, a temperature-sensitive ferrite 2 is magnetically attracted to a permanent magnet 3 and a light source
In order to prevent malfunction due to stray light, the light source 61 and the light receiving element 62 are provided with a tubular slit 12 for restricting the light propagation direction, with the temperature-sensitive ferrite 2 adsorbing the light receiving element 62 and the light receiving element 62 interposed therebetween. I have. When the temperature of the temperature-sensitive ferrite 2 is equal to or lower than the Curie temperature, the temperature-sensitive ferrite 2 is attracted to the permanent magnet 3 and no light arrives at the light receiving element 62.
Temperature-sensitive ferrite 2 when the temperature exceeds the Curie temperature
Falls away from the permanent magnet 3, and the light enters the light receiving element 62. That is, by monitoring the amount of light received by the light receiving element 62, the arrival of the temperature-sensitive ferrite 2 to the Curie temperature in this case is detected.

[0008]

When a temperature detecting device is constituted by using a temperature-sensitive ferrite and a permanent magnet, the presence or absence of the temperature-sensitive ferrite 2 can be determined by using a temperature detecting means having a configuration according to the prior art illustrated in FIG. The light source 61 and the light receiving element 62 having the electric signal wiring for detection are arranged in the immediate vicinity of the temperature-sensitive ferrite 2, and cannot meet the demand for isolating the temperature detection unit from the electric detection system. Even if an optical fiber is connected to each of the light source and the light receiving element and a temperature-sensitive ferrite is interposed between the two fibers, the separation force of the temperature-sensitive ferrite 2 from the permanent magnet 3 when the Curie point temperature of the temperature-sensitive ferrite 2 is reached is increased. Therefore, the mounting direction of the temperature detecting device is also restricted.

In addition, the permanent magnet 3 and the temperature-sensitive ferrite 2
Since it is housed in a housing provided for blocking stray light and providing a magnetic shield, it is not possible to visually check whether the temperature-sensitive ferrite is attracted to the permanent magnet or separated therefrom. That is, there is also a problem that the operation state cannot be visually confirmed by the detection unit. On the other hand, when light is guided by an optical fiber to separate the temperature detecting unit and the switch signal transmitting unit by applying the conventional technique illustrated in FIG. 7, the optical fibers 10 and 11 are applied from both ends of the temperature detecting unit.
Are pulled out in the opposite direction, so that in order to bind and route the optical fibers 10 and 11 in the wiring path between the switch signal transmitting unit 60 and at least one of the optical fibers, it is necessary to bend at least one of the optical fibers into a hairpin shape, It is necessary to secure a large space in the mounting portion to the temperature measuring object 20, and there is a problem that it becomes difficult to mount and wire in the field where there is not enough space.

The present invention has been made in view of the above points, and uses a temperature-sensitive ferrite as a temperature detecting means, and couples a temperature detecting section having no electric circuit to an isolated electric circuit section by an optical fiber. In the temperature detection device, the bias force other than gravity is used for the separation force between the permanent magnet and the temperature-sensitive ferrite when the Curie point temperature is reached, eliminating restrictions on the mounting direction and securing an excessive space for optical fiber wiring Means for adjusting the "variation" of the Curie point temperature of the temperature-sensitive ferrite and the "variation" of the biasing force of the member that provides the biasing force, while enabling the state of operation and non-operation to be visually confirmed from outside the device. And to reduce the “variation” of the operating temperature characteristics.

[0011]

According to a first aspect of the present invention, there is provided a temperature detecting apparatus comprising: a permanent magnet for magnetically attracting a temperature-sensitive ferrite; and a temperature-sensitive ferrite and a permanent magnet. A magnetic yoke made of a high-permeability magnetic material fixed to a permanent magnet to form a magnetic closed circuit;
A temperature detector is constituted by one shaft fixed to the temperature-sensitive ferrite and a spring coaxially attached to the shaft for applying a biasing force in a direction to separate the temperature-sensitive ferrite from the permanent magnet.

Then, the temperature detector is fixed to the other end of the shaft , or together with the shaft.
Fixed to the other end of the beam fixed to the temperature-sensitive ferrite
A light shielding plate that works is, a light projecting fiber for guiding the light emitted from the light source, a light receiving optical fiber for guiding the light to the light receiver light emitted from light projecting optical fiber, the light projecting Provided between the optical fiber and the optical fiber for receiving light, the introduction portions of the optical fiber for emitting light and the optical fiber for receiving light are arranged in parallel in the same direction, and reflect light in a direction orthogonal to the incident direction. , a reflecting surface of the two faces of the reflecting surface is curved in the common position of the focal point of each optical fiber receiving the light projecting end surface and both end faces intermediate to the common position, the shuffling <br / > Attached to the other end of the port or together with the shaft
Fixed to the other end of the beam fixed to the temperature-sensitive ferrite
An optical switch is constituted by a total reflection type reflector formed by forming a transparent member so as to have a U-shaped concave portion into which the interlocking light-shielding plate enters, and this optical switch and the above-mentioned temperature detecting portion are connected. To constitute a temperature detecting device. In addition,
In the temperature detecting section having this configuration, it is preferable that the temperature detecting section is configured so that the end of the magnetic yoke is extended to have a portion exposed outside the temperature-sensitive housing.

[0012] Then, the temperature detecting section receives the light emitted from the light emitting optical fiber, the light shielding plate interlocking with the shaft, the light emitting fiber for guiding the light emitted from the light source, and the light emitting fiber. A light-receiving optical fiber for guiding light to the light-receiving device, and a light-emitting fiber and a light-receiving optical fiber are provided so as to extend between the light-emitting fiber and the light-receiving optical fiber. The light is reflected in a direction perpendicular to the incident direction, and the light-collecting point is located at a common position between the end faces and both end faces of the projecting and receiving optical fibers. A total reflection type reflector having a surface and a transparent member formed at the common position so as to have a U-shaped concave portion into which a light shielding plate interlocking with the shaft enters. And the above temperature detector Out of configuring devices. In the temperature detecting section having this configuration, it is preferable that the temperature detecting section is configured so that the end of the magnetic yoke is extended to have a portion exposed outside the temperature-sensitive housing.

[0013] In a temperature detecting device according to a second aspect of the present invention for detecting the temperature of a temperature detection object in close contact with the object,
A temperature-sensitive ferrite fixedly provided on a heat-receiving plate attached in close contact with a temperature detection target, a permanent magnet for magnetically attracting the temperature-sensitive ferrite, a shaft fixed to the permanent magnet, and the permanent magnet And a spring attached to the shaft for applying a biasing force in a direction to separate the temperature-sensitive ferrite from the temperature-sensitive ferrite, and a temperature detecting unit is formed by connecting the temperature detecting unit and the optical switch.

In the temperature detecting device of the third invention, the permanent magnet for magnetically attracting the temperature-sensitive ferrite fixed on the heat receiving plate and the temperature-sensitive ferrite are provided on both sides of the permanent magnet so as to form a magnetically closed circuit. A pole piece made of a magnetic material having a high magnetic permeability is provided, a holding member for integrally holding the permanent magnet and the pole piece, a shaft fixed to the holding member, and a direction for separating the temperature-sensitive ferrite from the permanent magnet. A temperature detector is formed by a spring attached to the shaft that gives a force, and the temperature detector is combined with the optical switch to form a temperature detector. In this temperature detecting device, it is preferable that the pole pieces provided on both sides of the permanent magnet have a shape that becomes thinner as the distance from the surface in contact with the permanent magnet increases.

In any of the above temperature detecting devices,
It is preferable to provide a spring retainer which is movably mounted on a shaft on which a spring for applying a biasing force in a direction of separating the temperature-sensitive ferrite from the permanent magnet is attached, and which can change and set the deformation rate of the spring depending on the fixing position to the shaft. The spring retainer is then removed together with the spring from the shaft and is ready for mounting.

Further, in any of the above temperature detecting devices, the temperature-sensitive ferrite attracted to the permanent magnet, the permanent magnet for attracting the temperature-sensitive ferrite, and the high-side magnet provided on both sides of the permanent magnet for attracting the temperature-sensitive ferrite. The shaft fixed to one of the holding members that hold the pole piece made of a magnetic material of magnetic permeability and the permanent magnet together is separated from the temperature-sensitive housing of the temperature detection unit when the temperature-sensitive ferrite and the permanent magnet are separated. It is preferable that the temperature-sensitive ferrite and the permanent magnet are provided with a groove or a projection that can be held when the temperature-sensitive ferrite and the permanent magnet are in close contact with each other or when the permanent magnet is separated from the temperature-sensitive housing. .

[0017]

In the temperature detecting device according to the first aspect of the present invention using a temperature-sensitive ferrite, a magnetic yoke is provided to form a closed magnetic circuit, and the attraction force is transmitted without waste. At temperature, the temperature-sensitive ferrite and the permanent magnet are connected to each other by a repulsive force of a spring interposed so as to separate the bond between the temperature-sensitive ferrite and the permanent magnet. The repulsive force of the spring drives the temperature-sensitive ferrite in a direction to separate it from the permanent magnet in preference to other forces such as gravity. Then, when this separation occurs, the light-shielding plate connected to the temperature-sensitive ferrite via the shaft is used for the total reflection type reflector provided between the light emitting optical fiber and the light receiving optical fiber. Since the optical path is blocked by entering the U-shaped concave portion, an excess of the Curie temperature of the temperature detecting portion made of the temperature-sensitive ferrite is detected in the light receiving element. In the case of a temperature detecting device in which the end of the magnetic yoke is extended to be exposed outside the temperature-sensitive housing of the temperature detecting unit, the exposed portion may be used as a heat receiving plate which is attached to a temperature detection target object. it can.

[0018] A second configuration in which a temperature-sensitive ferrite is fixedly provided on a heat receiving plate attached in close contact with an object to be temperature-detected.
In the temperature detecting device of the present invention, the temperature-sensitive ferrite comes into close thermal contact with the temperature detection target via the heat receiving plate, and when the temperature of the temperature detection target changes, the temperature-sensitive ferrite can be generated in a short time. The temperature reaches the same temperature as the temperature of the temperature detection target. A pole piece made of a magnetic material having high magnetic permeability on both sides of the permanent magnet so that the permanent magnet that magnetically attracts the temperature-sensitive ferrite fixed on the heat receiving plate and the temperature-sensitive ferrite form a magnetic closed circuit. In the temperature detecting section of the third invention in which the permanent magnet and the pole piece are integrally held by the holding member, the temperature detecting object,
Therefore, when the temperature of the temperature-sensitive ferrite fixed to the heat-receiving plate is lower than the Curie point temperature of the temperature-sensitive ferrite and the value of the high magnetic permeability is maintained, the magnetic flux exiting the permanent magnet is not leaked by the magnetic yoke to the temperature-sensitive ferrite. Although the permanent magnet and the temperature-sensitive ferrite are strongly magnetically coupled and attract each other with a strong force, when the temperature exceeds the Curie point temperature of the temperature-sensitive ferrite, the value of the magnetic permeability of the temperature-sensitive ferrite greatly decreases. Then, the magnetic coupling between the permanent magnet and the temperature-sensitive ferrite disappears, and the attractive force between both disappears.
The permanent magnets and the temperature-sensitive ferrite are driven in directions separated from each other by a repulsive force of an intervening spring so as to separate the bond between the permanent magnet and the temperature-sensitive ferrite. In the temperature detecting device according to the third aspect of the present invention, if the pole pieces provided on both sides of the permanent magnet have a shape that becomes thinner as the distance from the surface in contact with the permanent magnet increases, portions that do not contribute to the guide of the magnetic flux of the pole piece are deleted. As a result, the movable portion is configured to be lightweight.

Further, in a temperature detection device in which a spring retainer is movably provided on a shaft on which a spring for applying a biasing force in a direction of separating the temperature-sensitive ferrite and the permanent magnet is provided, the spring retainer can be moved by changing the fixing position of the spring retainer with respect to the shaft. Because the deformation rate of the can be changed instead of the urging force,
By adjusting the fixed position of the spring retainer, the biasing force of the spring can be adjusted to be equal to the attractive force between the temperature-sensitive ferrite and the permanent magnet at the Curie point temperature. When the spring retainer is attached to the shaft together with the spring so that it can be removed, the biasing force is adjusted to be equal to the attractive force between the temperature-sensitive ferrite and the permanent magnet at the Curie point by adjusting the fixed position of the spring retainer. If not, the spring can be replaced with a spring having a different spring constant to enter the adjustable range.

Further, in a state where the temperature-sensitive ferrite is separated from the permanent magnet, a shaft fixed to a holding member for holding the temperature-sensitive ferrite or the permanent magnet or the permanent magnet and the pole piece is moved from the temperature-sensitive housing of the temperature detection unit. In the device having a protruding structure, when the temperature of the temperature detecting section exceeds the Curie temperature of the temperature-sensitive ferrite and the connection between the temperature-sensitive ferrite and the permanent magnet is separated, the shaft protrudes from the temperature-sensitive housing so as to be visible. Then, if a groove or a protrusion that can be pinched is provided at a terminal portion of the shaft protruding from the temperature-sensitive housing, the groove or the protrusion is gripped, and the temperature-sensitive ferrite and the permanent magnet are in close contact or separated. State can be set.

[0021]

FIG. 1 shows the configuration of an embodiment according to the first aspect of the present invention. In the embodiment of FIG. 1, the temperature-sensitive housing 1, the temperature-sensitive ferrite 2, the permanent magnet 3, the yoke 4 and the shaft 5 fixed to the temperature-sensitive ferrite 2, and the shaft 5 will be pushed up in the opposite direction to the permanent magnet 3. A spring 6 constitutes a temperature detecting section, and an optical switch 8 is constituted by a total reflection type reflector 9, a light projecting optical fiber 10, a light receiving optical fiber 11, and a light shielding plate 7 fixed to the shaft 5. It is configured. Hereinafter, the operation of the temperature detecting device according to the present embodiment will be described.

In FIG. 1, the temperature-sensitive ferrite 2 is magnetically attracted to a permanent magnet 3 fixed to a magnetic yoke 4. The magnetic yoke 4 is configured to return the magnetic flux generated by the permanent magnet 3 to the permanent magnet 3 via the temperature-sensitive ferrite 2. A shaft 5 to which a light shielding plate 7 is attached is fixed to the temperature-sensitive ferrite 2.
The temperature-sensitive ferrite 2 by the spring 6
Repulsion is acting in the direction of pulling away from. Then, the light-shielding plate 7 separates the temperature-sensitive ferrite 2 from the permanent magnet 3,
When the shaft 5 moves in the direction of the arrow, it enters the optical path of the optical switch 8 provided between the light projecting optical fiber 10 and the light receiving optical fiber 11 to block the signal light.

The optical switch 8 is made of a transparent optical member, for example, a transparent resin such as polymethyl methacrylate (PMMA) or polycarbonate (PC).
It has a mounting hole for the light emitting optical fiber 10 and the light receiving optical fiber 11 that are drilled in parallel, and the light emitted from the light emitting optical fiber 10 enters the light receiving optical fiber 11 through two reflections. Reflection surface arranged in the middle of the two curved reflection surfaces,
In order to allow the light-shielding plate 7 to enter, a total reflection type reflector 9 formed and provided with a U-shaped concave portion is provided. The curvature and the position of the two curved reflecting surfaces of the total reflection type reflector are determined by the fact that the light emitted from the light projecting optical fiber 10 is the first type of the total reflection type reflector.
Is reflected by the reflection surface of the first reflection surface, and is condensed at a middle point of a U-shaped concave portion provided between the two reflection surfaces. Light emitted from the middle point is reflected by the second reflection surface of the total reflection type reflector. On the condition that the light is reflected by the surface and condensed on the optical fiber 11 for light reception, it is obtained by calculation based on the law of reflection.

When the reflecting surface is formed as described above, the intersection angle between the normal to the light incident point on the reflecting surface and the incident light is about 45 °, and polymethyl methacrylate (PMM) is used.
A) or a critical angle θc (= 41 °) represented by the formula (1) in a transparent resin material having a relative refractive index with air such as polycarbonate (PC) of about 1.5. θc = sin ⁻¹ 1 / n (1) Therefore, if both reflecting surfaces are processed and formed sufficiently flat compared to the wavelength of the incident light, they become total reflection surfaces for the incident light. It is not necessary to add a special reflector for the purpose.

The magnetic attraction between the temperature-sensitive ferrite 2 and the permanent magnet 3 rapidly decreases near the Curie temperature as shown in FIG. Therefore, by setting the repulsive force of the spring 6 at a value between the maximum value and the minimum value of the attractive force as shown in FIG. 4, the operating temperature, that is, the temperature at which the temperature-sensitive ferrite 2 separates from the permanent magnet 3 is set close to the Curie temperature. Can be.

With the structure described above, the temperature-sensitive ferrite 2 separates from the permanent magnet 3 at the operating temperature, that is, the detected temperature,
The light shielding plate 7 blocks the optical path between the optical fibers, and is detected as a change in the amount of received light by a light receiving element provided at one end of the optical fiber for receiving light (not shown). Is converted into an electric signal and output as an abnormal temperature detection signal.

Next, FIG. 2 shows the structure of another embodiment of the first aspect of the present invention, which also employs the second and eighth aspects of the present invention. The present invention will be described below. In FIG. 2, the same reference numerals are given to the elements that function in the same manner as in the embodiment of FIG. 1, and the description thereof will be omitted. Also in this embodiment, the same optical switch 8 as that in the embodiment of FIG. 1 is applied, but its position is arranged apart from the axis of the shaft 5 attached to the temperature-sensitive ferrite 2 and the light shielding plate 7 is connected to the shaft 5 via a beam 52.

Since the optical switch 8 and the shaft 5 are disposed separately as described above, the temperature of the temperature detecting section rises above the Curie temperature of the temperature-sensitive ferrite 2 and the temperature between the temperature-sensitive ferrite 2 and the permanent magnet 3 is increased. When the magnetic attraction force disappears and the shaft 5 is pushed upward by the repulsive force of the spring 6, the upper end portion 51 of the shaft 5 projects outside the temperature-sensitive housing 1 and can be visually checked. Together with the optical switch 8 to enter the optical path of the optical switch 8 to block the signal light.

The color of the tip 51 of the shaft 5 is
The effect of visual confirmation can be further enhanced by making the color different from the color of. Further, in this embodiment, since the member of the end portion 41 of the magnetic yoke 4 is extended in a plate shape outside the temperature-sensitive housing 1 as the mounting portion 41 based on the invention of claim 2, the temperature detecting portion is thereby provided. Can be mounted.

FIG. 3 shows an embodiment of a temperature detecting device constructed according to the third aspect of the present invention. Also in this figure,
Elements that function the same as in the embodiment of FIG. 1 are given the same reference numerals, and descriptions thereof are omitted. In this embodiment, a temperature-sensitive ferrite 2 as a temperature detection sensor is used.
Is a heat receiving plate 21 that is attached in close contact with the temperature detection target.
The permanent magnet 3 is movably connected via a beam 52 to a shaft 5 to which a repulsive force is applied in a direction in which the permanent magnet 3 is separated from the temperature-sensitive ferrite 2 by a spring 6. With such a configuration, the temperature-sensitive ferrite 2
When the temperature of the temperature sensing object changes, the temperature-sensitive ferrite 2 reaches the same temperature as the temperature sensing object within a short time when the temperature of the temperature sensing object changes. I do.

FIG. 4 is a diagram showing an embodiment of a temperature detecting device constructed according to the fourth aspect of the present invention. In this figure as well, elements that function the same as in the embodiment of FIG. 1 are denoted by the same reference numerals, and a description thereof will be omitted. Also in this embodiment, the temperature-sensitive ferrite 2 serving as a temperature detection sensor is closely adhered and fixed directly above a heat receiving plate 21 which is attached closely to a temperature detection target.
Is a holding member made of lightweight material such as plastic
It is held by 53 and movably connected to the shaft 5.
On both sides of the permanent magnet 3, a temperature-sensitive ferrite 2
When the temperature is below the Curie temperature, the pole pieces 42a and 42 made of a magnetic material having high magnetic permeability so that all the magnetic flux emitted from the permanent magnet 3 is guided by the temperature-sensitive ferrite 2 and returns to the permanent magnet 3.
b is provided with an arrangement dimension selected, and the holding member
53, together with the permanent magnet 3.

As described above, when the pole pieces 42a and 42b are provided so that the leakage magnetic flux in the magnetic circuit constituted by the permanent magnet 3 and the temperature-sensitive ferrite 2 becomes small, the temperature-sensitive ferrite 2 becomes lower than the Curie temperature. At this time, the permanent magnet 3 and the temperature-sensitive ferrite 2 are strongly magnetically coupled to each other and attract each other with a strong force. When the temperature exceeds the Curie temperature, the strong attractive force disappears.
As a spring 6 for applying a repulsive force in a direction in which the temperature detecting device is separated from the magnet 3, a strong biasing force is used, and the operation of the temperature detecting device can be reliably and stably performed.

The magnetic flux passing through the magnetic member passes through the shortest path within a range where the magnetic permeability of the magnetic member is not saturated. Therefore, when the pole pieces 42a and 42b made of a magnetic material having a high magnetic permeability are arranged so that all the magnetic flux emitted from the permanent magnet 3 is guided by the temperature-sensitive ferrite 2 and returns to the permanent magnet 3, FIG. 2), the magnetic flux passing through the region f remote from the permanent magnet 3 and the temperature-sensitive ferrite 2 has a low density. Therefore, the magnetic flux of the pole piece provided on both sides of the permanent magnet 3 based on the invention of claim 5, as a thinner shape as the distance from the surface in contact with the permanent magnets as illustrated in FIG. 5 (b) Even if a region with a small density is deleted, the influence on the magnetic coupling between the permanent magnet 3 and the temperature-sensitive ferrite 2 is small, and a decrease in the mutual attractive force is kept small. Magnet 3, pole pieces 42a, 42b,
The weight of the movable part which is a component is reduced.

In the temperature detecting apparatus using the temperature-sensitive ferrite and the permanent magnet described in the above embodiments, a spring is used as a source of the urging force for separating the connection between the temperature-sensitive ferrite and the permanent magnet. There is some "variation" in the attraction force of the temperature-sensitive ferrite and the permanent magnet and the spring constant of the spring for each individual component. For this reason, even if the temperature detecting device is configured with the same structure and the same dimensions, "variation" occurs in the operating temperature. By the way, since the urging force obtained by the spring is proportional to the deformation rate of the spring as known by Hook's law, it is possible to adjust the deformation rate of the spring in the temperature detecting device of the embodiment already described. In this case, the biasing force of the spring fluctuates, and the temperature in the Curie temperature region, which balances with the attractive force between the temperature-sensitive ferrite permanent magnets, moves, so that the operating temperature can be adjusted to a predetermined temperature.

FIG. 6 is a partial view of a separation mechanism of an embodiment of a temperature detecting device capable of adjusting the biasing force for separating the coupling between the temperature-sensitive ferrite and the permanent magnet based on the invention of claim 6 of the present application. Show. In FIG. 6, the same reference numerals are given to the elements that function the same as those in the embodiment of FIGS. 1 to 4, and the description thereof will be omitted. In FIG. 6, reference numeral 5 denotes a pole piece made of a magnetic material having a high magnetic permeability provided on both sides of the temperature-sensitive ferrite attracted to the permanent magnet, the permanent magnet for attracting the temperature-sensitive ferrite, and the permanent magnet for attracting the temperature-sensitive ferrite. And a permanent magnet and a holding member for integrally holding the shaft and a permanent magnet, and a spring 6 for applying a biasing force in a direction of separating the permanent magnet from the temperature-sensitive ferrite is attached to the shaft 5 to the temperature detecting device. A male screw is formed in a direction in which the permanent magnet 2 and the temperature-sensitive ferrite 3 are provided from a position corresponding to the natural length of the spring in the set state. On the other hand, reference numeral 61 denotes a spring retainer which restricts the position of the end face of the spring 6 in which the female screw is cut so as to be tightly screwed into the screw portion of the shaft 5.

FIG. 6A shows a state in which the temperature has not reached the Curie temperature of the temperature-sensitive ferrite, and the permanent magnet 2 and the temperature-sensitive ferrite 3 are in close contact with each other.
The temperature reaches the Curie temperature of the temperature-sensitive ferrite and the spring 6
Shows a state in which the urging force exceeds the attraction force between the permanent magnet 2 and the temperature-sensitive ferrite 3 at the Curie temperature, and the two are separated from each other.

In FIG. 6, the spring retainer 61 is connected to the permanent magnet 2
When the thermosensitive ferrite 3 is twisted so as to move in the direction in which the thermosensitive ferrite 3 is provided, the deformation rate of the spring 6 increases, and the urging force of the spring for separating the permanent magnet 2 and the temperature sensitive ferrite 3 increases in proportion to the deformation rate. I do. By the way, although the magnetic permeability of the temperature-sensitive ferrite changes greatly on both sides of the Curie point, it has a certain range of temperature range as illustrated in FIG. The suction force changes depending on the temperature. Therefore, if the biasing force of the spring is changed by moving the set position of the spring retainer 61, the permanent magnet 2
The temperature between the temperature detecting device and the temperature-sensitive ferrite 3 is released and the temperature at which the temperature detecting device operates changes, so that the operating temperature can be adjusted. If the spring retainer is removed from the shaft together with the spring, and it can be attached, if the spring constant value is inappropriate and the adjustment to the predetermined operating temperature cannot be performed by adjusting the position of the spring retainer, an appropriate spring constant It can be adjusted to operate at a predetermined temperature by replacing the spring with a value.

Then, based on the invention of claim 9, FIG.
As shown in the embodiment of the shaft 5 described above, if a groove is provided in the end portion of the shaft 5 protruding from the temperature-sensitive housing 1, the groove is gripped with a tool such as tweezers and the temperature-sensitive ferrite is formed. It can be set to move to a state where the permanent magnet is in close contact with or away from the permanent magnet.

[0039]

According to the temperature detecting device of the present invention using the temperature-sensitive ferrite, the biasing force for separating the temperature-sensitive ferrite from the permanent magnet is provided by the spring, so that the effect that the mounting direction is not restricted is first obtained. . next,
The optical fiber for light emission and light reception is drawn out in the same direction, and an optical switch using a total reflection type reflector whose reflection surface is formed into a curved surface that has a condensing function is applied. It does not require any space to rotate it, and the light transmission loss is small, so the light emission power of the light source is small,
The effect of extending the life of the light source can also be obtained.

Also, a photodetector comprising an optical switch using a total reflection type reflector and an optical fiber, and a temperature detecting section not including an electric circuit and an electric circuit for converting an optical signal from the temperature detecting section into an electric signal, and a switching element. By connecting the circuit and the light source part, it is possible to completely separate and remotely install the temperature detection part and the electric circuit part, and it has electrical insulation, withstand voltage noise, and explosion proof. This has the effect of enabling temperature detection in an environment of electrical noise or temperature detection in an explosive environment.
Thus, in the device according to the second aspect of the present invention, which includes a member exposed at the end of the magnetic yoke outside the housing of the temperature detecting device, the exposed member can be used for mounting the temperature detecting device. The effect that it is not necessary to prepare separately is also obtained.

In the temperature detecting device according to the third aspect of the invention, in which the temperature-sensitive ferrite is fixedly mounted on a heat-receiving plate that is attached in close contact with the temperature-detecting object, the temperature-sensitive ferrite is provided via the heat-receiving plate. When the temperature of the temperature sensing object changes, the temperature-sensitive ferrite reaches the same temperature as the temperature of the temperature sensing object in a short time when the temperature of the temperature sensing object changes. Is faster,
The effect of reducing the temperature detection error is obtained.

In the temperature detector according to the third aspect of the present invention, in which pole pieces are provided on both sides of a permanent magnet magnetically attracting the temperature-sensitive ferrite fixed on the heat receiving plate, the magnetic flux exiting the permanent magnet is a pole. The piece is guided to the temperature-sensitive ferrite without leakage, and the permanent magnet and the temperature-sensitive ferrite are strongly coupled magnetically and attract each other with a strong force. The effect that a sufficient suction force is secured is obtained. When a pole piece that does not contribute to the guide of the magnetic flux of the pole piece is removed and becomes thinner as it moves away from the surface in contact with the permanent magnet, the movable portion having the permanent magnet and the pole piece as components is used. The weight can be reduced by that much, and there is an effect that the wear due to the operation of the movable portion is less likely to occur and the life of the temperature detecting device can be extended.

According to a sixth aspect of the present invention, there is provided a temperature detecting device which is provided with a spring holder which can be set to move and which can adjust a deformation ratio of a spring which applies an urging force for separating a coupling between a temperature-sensitive ferrite and a permanent magnet. For example, if the biasing force of the spring is changed by moving the set position of the spring retainer 61, the coupling between the permanent magnet 2 and the temperature-sensitive ferrite 3 is released, and the temperature at which the temperature detecting device operates changes. The effect of being able to adjust to the predetermined temperature is obtained well.If the spring retainer is removed from the shaft together with the spring and it can be mounted, the value of the spring constant is inappropriate and the position of the spring retainer is adjusted to the predetermined operating temperature by adjusting the position. If you can not
There is an effect that the spring can be adjusted to operate at a predetermined temperature by replacing the spring with an appropriate spring constant.

When a groove is provided at the end of the shaft 5 protruding from the temperature-sensitive housing 1, the groove is gripped by a tool such as tweezers, and the temperature-sensitive ferrite and the permanent magnet are in close contact with each other. Alternatively, since the moving temperature can be set to be distant, the operation of setting and adjusting the operating temperature can be easily performed. In a device in which the temperature-sensitive ferrite is separated from the permanent magnet and the shaft fixed to the temperature-sensitive ferrite or the permanent magnet or the holding member holding the permanent magnet projects from the temperature-sensitive housing of the temperature detection unit,
The effect that the operation / non-operation of the device can be visually recognized at the installation site of the temperature detection unit 1 is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the invention of claim 1;

FIG. 2 is an exploded perspective view of one embodiment of a temperature detecting device provided with a shaft and a mounting plate that also serves as a yoke, which are externally visible.

FIG. 3 is an exploded perspective view showing the configuration of an embodiment of the invention of claim 2;

FIG. 4 is an exploded perspective view showing the configuration of one embodiment of the invention of claim 3;

FIG. 5 is an explanatory view of a main part in an embodiment of the invention according to claims 3 and 8;

FIG. 6 is an explanatory view of a main part in an embodiment of the invention according to claims 6 and 9;

FIG. 7 is a conceptual explanatory view of a light detection type temperature detection device according to a conventional technique using a bimetal.

FIG. 8 is a conceptual diagram of temperature characteristics of magnetic attraction force of a temperature-sensitive ferrite.

FIG. 9 is an explanatory view of a conventional temperature detecting means using a temperature-sensitive ferrite.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 temperature-sensitive housing 2 temperature-sensitive ferrite 3 permanent magnet 4, 42 yoke 41 mounting part 42 a, 42 b pole piece 5 shaft 52 beam 53 holding member 6 spring 61 spring retainer 7 light-shielding plate 8 optical switch 81 lens 9 total reflection reflector 10 Optical fiber for light emission 11 Optical fiber for light reception 12 Optical slit 20 Temperature measuring object 21 Heat receiving plate 30 Bimetallic 60 Switch signal transmitter 61 Light source 62 Light receiving element 63 Switching circuit

Continuation of the front page (56) References JP-A-4-212028 (JP, A) JP-A-56-86322 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01K 1 / 02 H01H 37/58 G01K 7/36 G01K 11/12

Claims (9)

(57) [Claims] 1. A temperature detecting device for detecting a temperature by a change in a magnetic characteristic at a Curie point of a temperature-sensitive ferrite, comprising: a permanent magnet for magnetically attracting the temperature-sensitive ferrite; permanent magnetic yoke made of a magnetic material anchored high permeability to the permanent magnet so as to constitute a closed magnetic circuit, one and shafts <br/> bets of which is secured to the temperature sensing ferrite, the temperature sensitive ferrite A temperature detecting portion comprising a spring coaxially attached to the shaft for applying a biasing force in a direction to separate from the magnet, and a temperature detecting portion fixed to the other end of the shaft , or
Other than the beam fixed to the temperature-sensitive ferrite with the shaft
A light-shielding plate fixed to and linked to an end , a light-emitting fiber for guiding light emitted from a light source, and a light-receiving light for receiving light emitted from the light-emitting optical fiber and guiding the light to a light receiving element. A fiber, a light-projecting fiber, and a light-receiving optical fiber. The light-projecting fiber and the light-receiving optical fiber are introduced in parallel in the same direction. And the light converging point is located at a common position between the end faces and both end faces of the light emitting and receiving optical fibers, and the reflecting surface has two curved reflecting surfaces; At the other end of the shaft ,
Is fixed to the temperature-sensitive ferrite together with the shaft.
A total reflection type reflector formed by forming a transparent member so as to have a U-shaped concave portion into which a light-shielding plate which is fixedly connected to and linked to the other end of the beam enters. A temperature detecting device characterized by the above-mentioned. 2. The temperature detecting device according to claim 1, wherein an end of the magnetic yoke is extended to be exposed outside the temperature-sensitive housing of the temperature detecting unit. 3. A temperature detecting device for detecting a temperature by a change in a magnetic characteristic at a Curie point of a temperature-sensitive ferrite, wherein the temperature-sensitive ferrite is fixed on a heat receiving plate which is attached in close contact with a temperature detection target; a permanent magnet for attracting the temperature-sensitive ferrite magnetically, is secured to the permanent magnet 1
A temperature detecting unit comprising: a shaft; and a spring coaxially attached to the shaft for applying a biasing force in a direction of separating the permanent magnet from the temperature-sensitive ferrite; and a second end of the shaft . It is secured to the part, or the Shah
Other than the beam fixed to the temperature-sensitive ferrite with the shaft
A light-shielding plate fixed to and linked to an end , a light-emitting fiber for guiding light emitted from a light source, and a light-receiving light for receiving light emitted from the light-emitting optical fiber and guiding the light to a light receiving element. A fiber, a light-projecting fiber, and a light-receiving optical fiber. The light-projecting fiber and the light-receiving optical fiber are introduced in parallel in the same direction. And the light converging point is located at a common position between the end faces and both end faces of the light emitting and receiving optical fibers, and the reflecting surface has two curved reflecting surfaces; At the other end of the shaft ,
Is fixed to the temperature-sensitive ferrite together with the shaft.
A total reflection type reflector formed by forming a transparent member so as to have a U-shaped concave portion into which a light-shielding plate which is fixedly connected to and linked to the other end of the beam enters. A temperature detecting device characterized by the above-mentioned. 4. A temperature detecting device for detecting a temperature by a change in magnetic characteristics at a Curie point of a temperature-sensitive ferrite, the temperature-sensitive ferrite being fixed on a heat receiving plate attached in close contact with a temperature detection target; A permanent magnet that magnetically attracts the temperature-sensitive ferrite, and a pole piece made of a high-permeability magnetic material provided on both sides of the permanent magnet so that the permanent magnet and the temperature-sensitive ferrite constitute a magnetic closed circuit A holding member for integrally holding the permanent magnet and the pole piece; a shaft fixed to the holding member; and a shaft coaxial with the shaft for applying a biasing force in a direction to separate the temperature-sensitive ferrite from the permanent magnet. With the attached spring,
And the temperature detecting portion consisting of, is fixed to the other end of the shaft, or the Shah
Other than the beam fixed to the temperature-sensitive ferrite with the shaft
A light-shielding plate fixed to and linked to an end , a light-emitting fiber for guiding light emitted from a light source, and a light-receiving light for receiving light emitted from the light-emitting optical fiber and guiding the light to a light receiving element. A fiber, a light-projecting fiber, and a light-receiving optical fiber. The light-projecting fiber and the light-receiving optical fiber are introduced in parallel in the same direction. And the light converging point is located at a common position between the end faces and both end faces of the light emitting and receiving optical fibers, and the reflecting surface has two curved reflecting surfaces; At the other end of the shaft ,
Is fixed to the temperature-sensitive ferrite together with the shaft.
A total reflection type reflector formed by forming a transparent member so as to have a U-shaped concave portion into which a light-shielding plate which is fixedly connected to and linked to the other end of the beam enters. A temperature detecting device characterized by the above-mentioned. 5. The temperature detecting device according to claim 4, wherein the pole pieces provided on both sides of the permanent magnet have a shape that becomes thinner as the distance from the surface in contact with the permanent magnet increases. 6. The temperature detecting device according to claim 1, wherein the temperature-sensitive ferrite attracted by the permanent magnet, a permanent magnet that attracts the temperature-sensitive ferrite, and a permanent magnet that attracts the temperature-sensitive ferrite. The pole piece made of a magnetic material with high magnetic permeability provided on both sides of the arm is movably mounted on a shaft fixed to one of the holding members that integrally hold the permanent magnet and the permanent magnet. A temperature control device provided with a spring retainer capable of changing and setting a deformation rate of a spring attached to the shaft, which applies a biasing force in a direction of separating the spring from the shaft, by a fixing position with respect to the shaft. 7. The temperature detecting device according to claim 6, wherein a spring retainer movably mounted on the shaft is detachable together with the spring from the shaft and is attachable. 8. The temperature detecting device according to claim 1, wherein the shaft projects visually from a temperature-sensitive housing of the temperature detecting unit when the temperature-sensitive ferrite and the permanent magnet are separated from each other. A temperature detection device. 9. When the temperature-sensitive ferrite and the permanent magnet are separated from each other, the shaft is projected from the temperature-sensitive housing of the temperature detecting portion when the temperature-sensitive ferrite is separated from the permanent magnet. 9. The temperature detecting device according to claim 8, wherein a possible groove or projection is provided.