JPH10144189A - Thermally-actuated switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the final cutting off of an electric path, when this thermal reaction switch is used for protecting the electric motor of a hermetically sealed electric compressor. SOLUTION: In this switch 1, a hermetically sealed container is composed of a metallic container 2 and a lid plate 3, and conductive terminal pins 8A and 8B are insulating fixed to two through holes of the lid plate 3 by electric insulating fillers 7 respectively. A thermal reaction plate 5 is fixed in the container 2, and a contact mechanism is composed of a movable contact 6 and a fixed contact 9. A heater 10 is connected and fixed to the conductive terminal pin 8B and the lid plate 3, and when the contact is fused, a part of the heater 10 is fused to cut off the electric path. The sealed container inner side surfaces of the electric insulating fillers 7 are covered by heatproof inorganic insulater members 11. Since the surfaces of the electric insulating fillers 7 are converted by the heatproof inorganic insulator members 11, the arc generated in the fusing condition can be prevented from constituting a electric path capable of continuing, even though the spatter generated in the fusing condition of the heater 10 is attached.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermally responsive switch using a thermally responsive plate of bimetal or the like.
In particular, the present invention relates to a small-sized, thermally responsive, and inexpensive hermetically-sealed heat-responsive switch which is mounted inside a hermetically sealed container of a hermetically-sealed electric compressor such as a refrigerator or an air conditioner and used for protecting the electric motor.

[0002]

2. Description of the Related Art Conventionally, such a thermally responsive switch has been disclosed in Japanese Patent Publication No. 2519530, Japanese Patent Application Laid-Open No. 7-91375, Japanese Patent Application Laid-Open No. 7-241061, and the like. As shown in FIG. 7 and FIG. 8 which is a cross-sectional view taken along the line C--C of FIG. 7, the heat responsive switch 101 forms a closed container including a long dome-shaped pressure-resistant container 102 and a lid 103, and a bimetal or the like is provided inside the closed container. It has a contact opening / closing mechanism using a heat responsive plate 104 and a heater 105. One end of the thermally responsive plate 104 is connected and fixed to the container 102, and a movable contact 106 is fixed to the movable end, which is the other end, so as to be able to contact and separate from the fixed contact 107. The fixed contact 107 is fixed to a conductive terminal pin 108A which is fixed to the cover plate 103 through an insulating filler 109 such as glass in an airtight and electrically insulating state. The heater 105 has one end connected to the cover plate 103 and the other end connected to the conductive terminal pin 108B.

The thermal responsive switch 101 is provided as a motor protector by connecting one of the two conductive terminal pins 108A and 108B to the winding of the electric motor and the other end to a power supply. When the temperature becomes extremely high or an abnormal current flows through the motor, the thermally responsive plate 104 reverses to open the gap between the contacts. When the temperature falls to a predetermined value by natural cooling, the thermoresponsive plate 104 automatically returns and re-energizes. . In addition, by providing the fusing portion 105A in which a cross-sectional area of a part of the heater (heating element) 105 is smaller than a cross-sectional area of the other part, when the thermal operation switch exceeds the guaranteed number of times of operation, welding of a contact or the like occurs. When an abnormal current flows, the fusing section 105A of the heater is melted by the temperature rise due to the abnormal current, and the electric circuit is cut off to prevent the occurrence of a secondary abnormality, thereby operating as a double safety protection device. Things.

[0004]

As described above, this thermal responsive switch has exceeded the number of guaranteed operations, and when a contact is welded or the like, an abnormal rise in temperature causes a part of the heating element to be blown to cut off the electric circuit. On the other hand, when the electric compressor is used for a long time, insulation deterioration of the windings of the electric motor gradually progresses, and rarely, an interlayer short circuit occurs between the windings. In this case, a large current out of the rated value of the thermally responsive switch flows through the motor, so that an overcurrent relay such as a breaker located under the power supply to the electric compressor is normally activated and the power supply is cut off. If the overcurrent relay is out of order, the contacts of the thermally responsive switch may be welded due to a large current that is out of rating, and the motor may be burned.

[0005] Even if the contact of the thermal responsive switch 101 should be welded after the guaranteed number of operations,
As described above, the heater 105 is blown. However, when an accident such as a short-circuit of the winding of the motor is assumed, the heater 105 is generally defined by a difference in impedance of wiring from the power supply to the motor. Although not possible, the thermally responsive switch may be required to cut off a large current several tens of times the rated current. At such a large current, the heater of the thermal switch is blown, and the arc generated between the blown sections does not end easily. In particular, in a thermal switch which is miniaturized to improve the thermal response sensitivity. In addition, the insulating filler material 1 that insulates the conductive terminal pins 108B having different voltages from the cover plate 103
09, the creepage distance is relatively short. In particular, when the melted heater 105 adheres to the surface of the insulating filler 109, the insulation distance is further shortened, and an arc is easily transferred between the two. There is a danger that the glass as the filler is destroyed to lose airtightness, and that conduction between the conductive terminal pins and the cover plate occurs again.

[0006]

Therefore, in the thermally responsive switch according to the present invention, a pressure-resistant sealed container is constituted by a metal pressure-resistant container and a cover plate, and each of two through holes formed in the cover plate is provided. The conductive terminal pins are hermetically insulated and fixed by an electrically insulating filler, fixed contacts are fixed to one conductive terminal pin, one end of the heater is fixed to the other conductive terminal pin, and the other end of the heater is a lid. A thermally responsive plate fixedly connected to one of the plates and having a movable contact fixed to one side inside the pressure-resistant container, the movable contact being arranged so as to form a pair of switching contacts with the fixed contact; In the thermally responsive switch, the operating temperature is calibrated by deforming the vicinity of the fixed portion of the thermally responsive plate, and at the time of welding of the contacts, a part of the heater is blown to cut off the electric circuit. The switching contact is activated after the end of its life. The electric insulation between the conductive terminal pin and the cover plate, which is necessary to prevent the arc from continuing between the conductive terminal pin and the cover plate due to the spatter caused by the fusing of the heater when the welding is caused by an abnormally large current. A heat-resistant inorganic insulating member having a physical strength set in advance so as to be held is tightly fixed without any gap on the inner surface of the closed container of the electrically insulating filler material that fixes at least the conductive terminal pins to which the heater is fixed. By doing so, a large current at the time of abnormality can be cut off in the closed container of the switch.

Still another feature is that the material of the heat-resistant inorganic insulating member is zirconia (zirconium oxide).

Further, the heat-resistant inorganic insulating member and the electrically insulating filler are fixed with a heat-resistant inorganic adhesive.

Another feature of the heat-responsive switch of the present invention is that the pair of open / close contacts are provided at least on the inner peripheral edge of the through-hole formed in the cover plate to which the conductive terminal pin to which the heater is fixed is fixed. When welding due to an abnormally large current generated after the end of the service life, the resistance between the conductive terminal pin and the cover plate required to prevent the arc from continuing between the conductive terminal pin and the cover plate due to the spatter caused by the fusing of the heater. A large-diameter portion having a diameter of a predetermined size is provided to maintain electrical insulation, and a predetermined physical strength is obtained by filling the large-diameter portion with an electrically insulating filler. The insulation strength between the conductive terminal pins and the cover plate is substantially increased without increasing the size of the switch body.

Another feature is that a large-diameter portion having a large diameter is provided on the inner peripheral edge of the closed container in both of the through holes, and is filled with an electrically insulating filler.

Still another feature is that the depth of the large-diameter portion is less than one third of the thickness of the lid plate.

Still another feature of the present invention resides in that the component of the gas sealed in the sealed container is helium of 30% or more.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a thermoresponsive switch according to the present invention. 1 and 2 are a side view and a plan view of the present embodiment, FIG. 3 is a longitudinal sectional view thereof, and FIG.
3 is a sectional view taken along the line AA of FIG. The thermally responsive switch 1 of the present invention
Is a pressure-resistant container 2 made by pressing a steel plate or the like with a press.
The pressure vessel 2 has a substantially dome-like shape on both sides and has a long dome shape connecting both ends by a semicircular central portion. The shape of the pressure-resistant container 2 is not limited to such a long dome shape. If the strength is obtained by providing ribs along the longitudinal direction of the container, for example, the shape of the pressure-resistant container 2 is necessarily limited to a super dome shape. There is no. A lid plate 3 formed by molding a thicker iron plate than the container is hermetically sealed at the opening of the pressure-resistant container 2 by ring projection welding or the like.

Inside the pressure vessel 2, a bimetal or trimetal is drawn into a shallow dish through a support 4 made of a suitable metal plate, and is thermally responsive to an operation reversal temperature within a predetermined range. One end of the plate 5 is connected and fixed, and a movable contact 6 is fixed to the other end of the thermally responsive plate 5. The heat responsive switch 1 is calibrated to a predetermined operating temperature by adjusting a contact pressure with a fixed contact, which will be described later, by crushing and deforming a portion of the pressure-resistant container 2 to which the support 4 is fixed from the outside.
The fixing position of the support 4 is set at one end of the pressure-resistant container 2 in the embodiment. For example, when a smaller heat-responsive switch is used, the heat-responsive plate 5 is fixed near the center of the pressure-resistant container. May be. The shape of the support 4 may be a button shape or the like instead of the shape shown in the drawing. Further, when the heat-responsive plate 5 is fixed to the pressure-resistant container, it does not substantially affect the preset operation reversal temperature. If so, support 4
Can be omitted.

The cover plate 3 is provided with through holes 3A and 3B. Each of the through holes 3A and 3B is formed with an electrically insulating filler 7 such as glass in consideration of a coefficient of thermal expansion.
A and 8B are hermetically insulated and fixed by a well-known compression type hermetic seal. A fixed contact 9 is fixed near one end of the conductive terminal pin 8A on the inner side of the sealed container, and is arranged so as to face the movable contact 6 described above and to be able to contact and separate therefrom.

One end of a heater 10 as a heating element is fixed near the tip of the other conductive terminal pin 8B on the inner side of the sealed container, and the other end of the heater 10 is fixed on a lid plate. The heater 10 is disposed substantially along the periphery of the conductive terminal pin 8B, and is disposed substantially in parallel with the thermally responsive plate 5 to improve the heat exchange relationship. The heater 10 is provided with a fusing portion 10A having a smaller sectional area than other portions. During normal operation of the compressor, which is the device to be controlled, the fusing section 10A is not blown by the operating current of the motor, and when the motor is in the constrained state, the thermally responsive plate 5 reverses in a short time to open the gap between the contacts. In this case, the fusing portion is not blown off. If this thermal responsive switch repeatedly opens and closes for a long period of time, it may not be able to be opened due to welding of the contacts after the guaranteed number of operations. In that case, the fusing section 10
Since the temperature of A rises shortly after that, the energization to the electric motor can be reliably cut off.

Since such a thermally responsive switch 1 is used inside a hermetic container of a hermetic electric compressor, it needs to be downsized from the viewpoint of installation space and thermal responsiveness.
There is a demand for the performance of a motor having a larger rated operating current as a protector. More specifically, in the case of an excessive current such as when the rotor is locked by the motor, the ratio between the time until the contacts are opened (Short Time Trip: S / T) and the time until the contacts are returned is set to an appropriate value. There is also a demand to improve the protection performance of the battery and to further increase the maximum current value capable of continuous operation. Therefore, in the present invention, the heat from the heater 10 can be efficiently transferred at the time of an excessive current by the heat responsive plate 5.
Helium having good thermal conductivity is enclosed as a gas in the closed container of the switch in an amount of 30% or more. The withstand voltage tends to decrease as the helium encapsulation ratio increases. In the case of 100% helium at around 1 atm at room temperature, the withstand voltage decreases and the power supply voltage used is limited. Therefore, for a normal commercial power supply, the amount of helium is preferably in the range of 30% or more and 95% or less. It is known that a small percentage of helium is mixed into the sealed gas for airtight inspection of the switch container, but if it is less than 30%, a sufficient effect of heat conduction cannot be obtained.

For example, a gas mixture of 90% helium at room temperature and 1.3 atm with helium filled with nitrogen or dry air is described as an example. In response to a rapid rise in internal temperature, such as time, the enclosed helium quickly transfers the heat of the heater 10 to the thermally responsive plate 5, so that the thermally responsive plate 5 may be one filled with nitrogen or dry air. The time (S / T) from when the operating temperature is reached and the contacts are opened earlier can be shortened, and immediately after that, heat energy is stored in the closed container of the switch and the return time is lengthened to increase the motor time. Improves the protection characteristics of the winding. Also, during rated operation, the temperature rise of the heat-generating part such as the heater is slower than at the time of excessive current, so helium with good thermal conductivity quickly transfers heat to the closed container of the switch, and the heat is Further, since the heat is radiated to the outside, the temperature of the thermally responsive plate 5 hardly rises and does not reach the operating temperature, and the rated operating current value (Ulti
mate Trip Current: U.S. T. C. ) Can be raised.

As described above, the amount of helium in the sealed gas is reduced to 3
By setting it to 0% or more, the time (S / T) until the contacts are opened at a normal temperature for a predetermined time, for example, 10 seconds, and a current value and a rated operating current value (UTC). The present invention proposes a thermally responsive switch that can be reduced in size and inexpensive without deteriorating the performance of the electric motor and can be operated with sufficient safety.

When the electric compressor is used for a long period of time, the insulation of the windings of the electric motor gradually deteriorates, and in rare cases, a short circuit occurs between the windings. In this case, if the thermal operation switch has exceeded the guaranteed operation count and contact welding has occurred, short-circuit current will continue to flow, and furthermore, the overcurrent relay such as a breaker at the source of the power supply to the electric compressor will fail. And there is a danger that the motor will burn out. Therefore, the conventional thermal switch 1
In this case, the electric circuit is cut off by fusing the heater 105 even in such a case. However, since the short-circuit current of the motor is several tens of times the rated current, the heater of the heat-responsive switch is not used. The arc generated between the fusing portions at the time of fusing does not easily end. for that reason,
In particular, the electrically insulating filler material 1 between the conductive terminal pins 108B
If the arc is transferred on the surface of the surface 09, the electric insulating filler material 109 is destroyed and the airtightness is lost, or a short circuit occurs between the conductive terminal pins 108A and 108B, so that the electric circuit cannot be cut off. There are cases.

The findings obtained from the experiments are as follows.
The heater 105 is melted at the fusing portion 105A. More specifically, since both ends of the heater are connected and fixed to the cover plate 103 and the conductive terminal pins 108B, heat is slightly released to generate a temperature gradient, and the temperature rises most. This occurs near 105A1, which is the center of the heater at the fusing portion, and fusing occurs at this portion. At the time of this fusing, an arc is generated because both ends have different voltages, and the periphery of the arc is heated by the heat of the arc, so that the arc can be easily maintained.

Here, if the arc extends along the heater 105, the discharge distance of the arc becomes longer as the heater is melted, and the arc disappears soon. However, when the thermally responsive switch is designed to be small, it is difficult to sufficiently obtain the creepage distance of the electrically insulating filler 109 such as glass.
Therefore, in the case of a large current, the arc may transfer between the cover plate 103 and the conductive terminal pin 108B. In particular, a part of the melted heater 105 may be melted and scattered as small pieces to form spatter and adhere on the electrically insulating filler 109 to form an electric path for the arc. Also in this case, the conductive terminal pin 108B and the cover plate may be formed. There is a possibility that the arc will continue to transfer between the conductive terminal pins 103 and between the conductive terminal pins via the cover plate. In order to further reduce the size of the thermoresponsive switch, the through hole 103
The sizes of A and 103B are naturally limited. In other words, in order for the electrically insulating filler to have sufficient strength as a compression type hermetic seal, the surrounding lid plate must have sufficient physical strength,
Therefore, for example, the insulation distance between the conductive terminal pins and the cover plate may be only about 1 mm. When the insulation distance between the conductive terminal pins and the cover plate is short, it is very difficult to secure the insulation distance when spatter adheres when the heater is blown.

In such a case, the arc is not easily extinguished, and the heat capacity of the conductive terminal pin 108B is relatively small, so that the temperature of the conductive terminal pin and the electrically insulating filler 109 for fixing the terminal airtightly increases. There is a danger that the airtightness will be deteriorated due to melting and destruction, and furthermore, the conductive path will not be cut off in the closed container of the switch due to the conductive terminal pins 108B touching the cover plate.

Therefore, in the thermally responsive switch 1 of the present invention, as shown in FIGS. 3 and 4, physical strength such as electric strength against creeping discharge and heat resistance against spattering, etc., set on the electrically insulating filler 7 in advance. A heat-resistant inorganic insulating member 11 made of ceramics or the like in consideration of the strength is tightly fixed without any gap. Therefore, when the switching contact of the thermally responsive switch has expired and has been welded due to an abnormal current after the end of its life, the heater is blown off. Further, the spatter generated at the time of the heater blowout adheres to the surface of the heat-resistant inorganic insulating member 11. Also, sufficient electric insulation resistance can be obtained. The shape and size of the heat-resistant inorganic insulating member 11 are determined in advance in consideration of the required physical strength from the current value cut off by the thermally responsive switch, the amount of spatter generated when the heater blows, and the like. By doing so, the lid plate has sufficient hermetic sealing strength to fix the conductive terminal pins without increasing the size of the thermally responsive switch, and also improves the electrical insulation resistance between the conductive terminal pins and the lid plate The arc can be prevented from continuing between the conductive terminal pins and the cover plate due to the spatter caused by the fusing of the heater. Accordingly, it is possible to interrupt a large current in the case of an abnormality in the closed container of the switch.

Even when a heat-resistant inorganic insulating member 11 such as ceramics provided on the electrically insulating filler 7 fixing the conductive terminal pins 8B on the heater 10 side is attached, a part of the heater is blown. If the physical strength for preventing insulation from being maintained between the conductive terminal pins 8B and the cover plate 3 due to sputtering generated when the current is interrupted is insufficient, the conductive terminal pins 8A on the fixed contact 9 side are fixed. By attaching the heat-resistant inorganic insulating member 11 also to the electrically insulating filler 7 that has been used, the arc can be prevented from continuing between the conductive terminal pins 8A and 8B.

The heat-resistant inorganic insulating member 11 is preferably made of a material having a sufficiently high melting point with respect to glass, such as ceramics, in order to adhere to glass. By using such a heat-resistant inorganic insulating member having a high melting point, the heat-resistant inorganic insulating member 11 and the electric insulating filler 7 can be adhered to each other in the following manner. For example, when fixing the conductive terminal pins 8A, 8B to the through holes 3A, 3B of the cover plate 3, a glass pellet as the electrically insulating filler 7 and the heat-resistant inorganic insulating member 11 are set and an atmosphere furnace at about 1000 ° C. Melts only the glass pellet by passing through, and the conductive terminal pins 8A, 8B
Is fixed, and at the same time, the heat-resistant inorganic insulating member 11 and the electrically insulating filler 7 can be adhered to each other without gaps.

As a material of the heat-resistant inorganic insulating member 11, for example, ceramics such as alumina can be considered. In particular, when glass is used for the electrically insulating filler 7 and it is directly adhered as described above, the expansion coefficient and the like are determined. Therefore, it is desirable to use zirconia (zirconium oxide) having good adhesion to glass. Also, for example, a heat-resistant inorganic insulating member 1
1 may be adhered to the electrically insulating filler 7 with a heat-resistant inorganic adhesive mainly composed of ceramics or the like. In this case, as the heat-resistant inorganic insulating member, not only alumina but also electrically insulating filler such as glass may be used. It is possible to use a material having poor direct adhesion to the material, and the conditions for selecting the material are relaxed.

Next, another embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 5 is a longitudinal sectional view of this embodiment,
FIG. 6 is a sectional view taken along the line BB of FIG. In this thermal responsive switch 21, the same components as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In this thermally responsive switch 21, the conductive terminal pins 8
In order to increase the creepage distance between the A and 8B and the cover plate 23 and to increase the physical strength, a large-diameter portion 23A is formed inside the closed container of the through holes 23A and 23B into which the conductive terminal pins 8A and 8B are inserted.
1, 23B1 are provided, and the electrically insulating filler 7 including these large diameter portions is filled.

As a method of increasing the creepage distance by the electrically insulating filler, for example, instead of providing a large diameter portion in the through holes 23A and 23B, the diameter of the through hole itself is increased as in the thermally responsive switch 111 shown in FIG. Can be considered. In this thermal responsive switch 111, the same components as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. The cover plate 112 of the thermally responsive switch 111 is provided with large-diameter through holes 112A and 112B, and the conductive terminal pins 8A and 8B are hermetically insulated and fixed to the respective through holes by the electrically insulating filler 7. . However, when making the switch smaller, if such large-diameter through holes 112A and 112B are drilled, an intermediate portion 112C between the two through holes is formed.
Is very narrow and has no strength, and there is a problem in that the fixing strength between the electrically insulating filler 7 and the two through holes is insufficient for a compression type hermetic seal.

Therefore, in the present invention, the diameters of the through-holes 23A and 23B are the same as in the prior art and the large-diameter portion 23 is shown in FIGS.
By providing A1, 23B1, the strength of the electrically insulating filler 7 can be obtained, and at the same time, a sufficient creepage distance between the conductive terminal pins 8A, 8B and the cover plate 23 can be obtained. Therefore, even when a part of the melted heater 10 adheres to the surface of the electrically insulating filler 7 as spatter, it is possible to make it more difficult to form an electric circuit than before, and an arc is scattered on the surface of the electrically insulating filler. Can be prevented. Further, the large diameter portion 23A1,
If the depth of 23B1 is too deep, the electrically insulating filler 7
However, in the present invention, by setting the depth to be not more than one third of the thickness of the cover plate 23, the performance as a compression seal is not deteriorated, and Electric insulation performance can be improved.

[0031]

According to the heat responsive switch of the present invention, when the switching contact of the switch is welded due to an abnormally large current generated after the end of the life, the spatter scattered when the heater is blown is generated between the conductive terminal pin and the cover plate. Even if it adheres between
At least the heater is fixed to a heat-resistant inorganic insulating member having a physical strength set in advance so as to maintain electric insulation resistance between the conductive terminal pins and the cover plate necessary to prevent the arc generated at the time of fusing from continuing. By tightly fixing the electrically insulative filler material fixing the conductive terminal pins on the inner surface of the inside of the closed container without any gap, a large current at the time of abnormality can be cut off in the closed container of the switch.

Particularly when the electrically insulating filler is glass, more reliable adhesion can be obtained by using zirconia having a coefficient of expansion close to that of glass as the material of the heat-resistant inorganic insulating member.

Further, by fixing the heat-resistant inorganic insulating member and the electric insulating filler with a heat-resistant inorganic adhesive, it is possible to use a material having poor direct adhesion to the electric insulating filler. The conditions for material selection are relaxed.

According to the heat responsive switch of the present invention, the pair of open / close contacts have a life span at least on the inner peripheral edge of the through-hole formed in the cover plate to which the conductive terminal pin to which the heater is fixed is fixed. Electric insulation between the conductive terminal pin and the cover plate required to prevent the arc from continuing between the conductive terminal pin and the cover plate due to spatter caused by the fusing of the heater when the welding is performed due to an abnormally large current generated after the termination. A large diameter portion having a diameter of a predetermined size is provided so as to maintain the property, and a predetermined physical strength can be obtained by filling the large diameter portion with an electrically insulating filler. Electric insulation resistance between the conductive terminal pins and the cover plate can be substantially increased without increasing the size of the switch body.

Further, by setting the depth of the large diameter portion to one third or less of the thickness of the lid plate, it is possible to prevent the performance as a compression type hermetic seal from being deteriorated.

A heat-resistant inorganic insulating member can be tightly fixed on the inner surface of both electrically insulating fillers on the inner side of the closed container without any gap, or a large-diameter portion having a large diameter can be provided on the inner peripheral edge of the closed container of both through holes. Is provided and the electrically insulating filler is filled, whereby the electrical insulation resistance between the conductive terminal pins and between the conductive terminal pins and the cover plate can be further improved.

Further, by setting the component of the gas sealed in the closed container to 30% or more of helium, the time (S / T) until the contact is opened is a predetermined time at normal temperature, and the current value and the rated value are set. The operating current value (UTC) can be approximated, and the motor can be reduced in size and inexpensive without deteriorating the performance of the motor, and can be operated with sufficient safety.

[Brief description of the drawings]

FIG. 1 is a side view of an embodiment of a thermally responsive switch according to the present invention.

FIG. 2 is a plan view of one embodiment of the thermally responsive switch of the present invention.

FIG. 3 is a longitudinal sectional view of one embodiment of the thermally responsive switch of the present invention.

FIG. 4 is a sectional view of the thermally responsive switch shown in FIG.

FIG. 5 is a longitudinal sectional view of another embodiment of the thermally responsive switch of the present invention.

6 is a sectional view of the thermally responsive switch of FIG.

FIG. 7 is a longitudinal sectional view of one embodiment of a conventional thermal switch.

8 is a sectional view of the thermally responsive switch of FIG. 7 taken along the line CC.

FIG. 9 is a longitudinal sectional view showing a problem of the thermally responsive switch.

[Explanation of symbols]

 1, 21: thermal response switch 2: pressure-resistant container 3, 23: lid plate 3A, 3B, 23A, 23B: through hole 4: support body 5: thermal response plate 6, movable contact 7: electrically insulating filler 8A, 8B : Conductive terminal pin 9: Fixed contact 10: Heater 10 A: Fusing section 11: Heat resistant inorganic insulating member 23A1, 23B1: Large diameter section

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihisa Ueda 4-30, Hoshocho, Minami-ku, Nagoya-shi Co., Ltd. Inside the Company Ikukata Factory (72) Inventor Hideki Koseki 4-30, Hoshocho, Minami-ku, Nagoya-shi Stock Company Inside the company student factory

Claims (8)

[Claims] 1. A pressure-resistant airtight container is constituted by a metal pressure-resistant container and a lid plate hermetically fixed to an opening end thereof, and conductive terminal pins are electrically insulated in each of two through holes formed in the lid plate. A fixed contact is fixed to one conductive terminal pin, one end of the heater is fixed to the other conductive terminal pin, and the other end of the heater is connected and fixed to the lid plate, Inside the container, a movable contact is fixed to one side, and a heat-responsive plate set so as to be drawn in the shape of a dish in the vicinity of the center and set to flip rapidly at a predetermined temperature is conductively connected and fixed, and the movable contact of the heat-responsive plate is fixed. Are arranged so as to form a pair of switching contacts with the fixed contacts, and calibrate the operating temperature by deforming the vicinity of the fixed portion of the thermally responsive plate of the pressure-resistant container. Thermo-responsive switch that can shut off In the case where the pair of switching contacts are welded by an abnormally large current generated after the end of the life, it is necessary to prevent the arc from being continued between the conductive terminal pin and the cover plate by sputtering caused by the fusing of the heater. A heat-resistant inorganic insulating member having a predetermined physical strength to maintain electrical insulation between the conductive terminal pin and the cover plate is electrically insulated by fixing at least the conductive terminal pin to which the heater is fixed. A thermally responsive switch characterized in that a large current in the event of an abnormality can be cut off within the closed container of the switch by tightly fixing the filler on the inner surface of the closed container without any gap. 2. The thermally responsive switch according to claim 1, wherein a heat-resistant inorganic insulating member is tightly fixed on the inner surface of both the electrically insulating fillers on the inner side of the closed container without any gap. 3. The thermally responsive switch according to claim 1, wherein the material of the heat-resistant inorganic insulating member is zirconia. 4. The heat-generating device according to claim 1, wherein the heat-resistant inorganic insulating member and the electric insulating filler are fixed with a heat-resistant inorganic adhesive. Response switch. 5. A pressure-resistant hermetic container is constituted by a metal pressure-resistant container and a lid plate hermetically fixed to an open end thereof, and conductive terminal pins are electrically insulated in each of two through holes formed in the lid plate. A fixed contact is fixed to one conductive terminal pin, one end of the heater is fixed to the other conductive terminal pin, and the other end of the heater is connected and fixed to the lid plate, Inside the container, a movable contact is fixed to one side, and a heat-responsive plate set so as to be drawn in the shape of a dish in the vicinity of the center and set to flip rapidly at a predetermined temperature is conductively connected and fixed, and the movable contact of the heat-responsive plate Is detachably connected to the fixed contact,
In a thermally responsive switch, the operating temperature is calibrated by deforming the vicinity of the fixed portion of the thermally responsive plate of the pressure-resistant container, and at the time of welding of the contacts, a part of the heater is blown to cut off the electric circuit. Fusing of the heater when the pair of on-off contacts are welded to the inner peripheral edge of the through-hole formed in the lid plate to which the conductive terminal pins to which the heater is fixed are fixed due to an abnormally large current generated after the end of the life. It has a diameter of a predetermined size so as to maintain electric insulation between the conductive terminal pin and the cover plate necessary to prevent an arc from continuing between the conductive terminal pin and the cover plate due to spatter. A large-diameter portion is provided, and by filling this large-diameter portion with an electrically insulating filler material, a predetermined physical strength can be obtained and the switch can be electrically conductive without increasing the size of the switch body. Thermo-switch, characterized in that substantially increase the electromigration insulation between child pin and the cover plate. 6. The thermally responsive switch according to claim 5, wherein a large-diameter portion having a large diameter is provided at the inner peripheral edge of the closed container in both of the through holes and is filled with an electrically insulating filler. 7. The thermally responsive switch according to claim 5, wherein a depth of the large diameter portion is one third or less of a thickness of the lid plate. 8. The thermally responsive switch according to claim 1, wherein a component of a gas sealed in the closed vessel is 30% or more of helium.