JPH11285143A - Power terminal block - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a power supply terminal block having a current fuse capable of reducing a fusing set current value and storing in a space-saving manner. Provided is a power supply terminal block that can also cut off power supply. SOLUTION: The conductive fusible member is connected on an energizing path to a load side supplied from a power supply and is blown at a finite set current value. The conductive fusible member has substantially U-shaped portions U1 to U4. A current fuse 6 having at least four fuses is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply terminal block capable of completely preventing an accident due to overcurrent and / or abnormal heat generation at an early stage.

[0002]

2. Description of the Related Art Conventionally, a current fuse is provided in a circuit in order to prevent a connected device from being damaged by an overcurrent, and a current fuse element is blown by the Joule heat against a steep overcurrent. There is a device to make it. In addition, a temperature switch using a shape memory alloy or bimetal is provided in the circuit for abnormal heat generation that occurs when the external conductor is incompletely inserted into the power terminal block. There is a device that blows the fuse by the Joule heat by applying a steep overcurrent to the current fuse element.

[0003]

SUMMARY OF THE INVENTION In contrast to conventional devices,
In order to detect an abnormal current earlier, when the conductive fusible material that is the material of the current fuse is a single material, the length L in the current direction of the conductive fusible material 50 shown in FIG. The width w of the cross-sectional area perpendicular to the width must be small, and the thickness t must be small.

On the other hand, in order to avoid a malfunction of the temperature switch due to an increase in temperature, the temperature switch does not operate at 90 ° C. or lower, and at 100 ° C. or higher which occurs when the external conductor is incompletely inserted into the power terminal block. In order to reliably cut off the current at the time of temperature rise, when a shape memory alloy or bimetal is used, a part for suppressing deformation at 90 ° C. or lower must be newly provided. Further, in the method of stopping the energization of the load circuit by the operation of the shape memory alloy or the bimetal and forming a short circuit including a current fuse to blow the current fuse at the time of abnormal temperature rise, the current supply to the load side is cut off. However, the power line on the primary side is not cut off. Further, the use of expensive shape memory alloys and bimetals increases costs.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a power supply terminal block having a current fuse capable of reducing a set fusing current value and storing the same in a space-saving manner, and cutting off power supply to a load circuit when abnormal heat is generated. It is another object of the present invention to provide a power supply terminal block that can cut off the power supply to the transmission side.

[0006]

A power supply terminal block according to claim 1 is made of a conductive fusible material which is connected on a current supply path from a power supply to a load side and is blown off at a finite set current value. And a current fuse having at least four substantially U-shaped portions in the conductive fusible member.

The power supply terminal block according to claim 2 is the power supply terminal block according to claim 1, wherein a tensile stress is applied to the conductive fusible member in a state where the conductive fusible body is electrically connected to another conductor on an energizing path. Is added.

A power supply terminal block according to a third aspect is the power supply terminal block according to the first or second aspect, wherein at least one portion where the substantially U-shaped portion of the conductive fusible body opens at a wide angle is provided.
It is characterized in that it exists in some places.

A power supply terminal block according to a fourth aspect is the power supply terminal block according to any one of the first to third aspects, wherein a metal cross-sectional area perpendicular to a direction of a current flowing through the conductive fusible material is partially reduced. It is characterized by having.

A power supply terminal block according to a fifth aspect is the power supply terminal block according to any one of the first to fourth aspects, wherein a part of the conductive fusible material is coated with a low thermal conductive material. It is characterized by.

A power supply terminal block according to a sixth aspect is the power supply terminal block according to any one of the first to fifth aspects, wherein the conductive fusible member is such that a distance between two U-shaped central portions is adjacent to each other. It is characterized by being shorter than the U-shape of any combination.

A power supply terminal block according to a seventh aspect is the power supply terminal block according to any one of the first to sixth aspects, wherein the conductive fusible member is on an energizing path from a power supply to a load side and has a set current. When a current equal to or larger than the value is supplied, the fuse is blown to protect the load, and is blown by forming a short circuit that does not pass the load even when abnormal heat is generated.

The power supply terminal block according to claim 8 is:
That the insulating resin softened by the heat of the arc generated when the contact between the external conductor from the power supply and the electrode plate of the power terminal block is incomplete is fixed to the insertion portion of the external conductor or the vicinity of the electrode plate. Features.

According to a ninth aspect of the present invention, the power supply terminal block is the power supply terminal block according to the eighth aspect, wherein the insulating resin softened by abnormal heating due to the bad contact of the external conductor is added with a flame retardant material. It is characterized by.

The power supply terminal block according to claim 10 is the power supply terminal block according to claim 8 or 9, wherein the insulating resin which is softened by abnormal heating due to poor contact of the external conductor is either a conductor or an electrode plate in a solid state. Characterized by being in contact with the crab.

A power supply terminal block according to claim 11 is the power supply terminal block according to any one of claims 8 to 10,
The insulating resin that is softened by abnormal heating due to poor contact of the external conductor has a viscosity of 100 cp or less at 100 ° C. or higher.

The power supply terminal block according to claim 12 comprises two conductive metal plates and a heat-meltable insulator sandwiched between the metal plates and softened at a finite set temperature value. Wherein at least one of the conductive metal plates is provided with a temperature switch having a protruding portion that makes conductive contact when the heat-meltable insulator is softened.

According to a thirteenth aspect of the present invention, there is provided the power supply terminal block according to the twelfth aspect, wherein at least one of the conductive metal plates has a hole into which the softened heat-meltable insulator is melted. It is characterized by having.

A power supply terminal block according to a fourteenth aspect is the power supply terminal block according to the twelfth or thirteenth aspect, wherein the conductive metal plate provided with the holes is a metal plate side having a factor of increasing the temperature. It is characterized by the following.

A power supply terminal block according to a fifteenth aspect is the power supply terminal block according to any one of the twelfth to fourteenth aspects, wherein the heat-fusible insulator has a flame-retardant material or a flame-retardant material added. It is characterized by becoming.

A power supply terminal block according to claim 16 is the power supply terminal block according to any of claims 12 to 15, wherein a compressive stress is applied to the heat-fusible insulator by two conductive metal plates. It is characterized by having.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a power supply terminal block according to the present invention will be described with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is an exploded view of a circuit showing an embodiment of a power supply terminal block according to the present invention, and shows a configuration of a power supply terminal block which can completely prevent an accident due to overcurrent and abnormal heat generation at an early stage. An example shown, FIG.
FIG. 3 is a perspective view showing a shape of a current fuse in the power supply terminal block in FIG. 1; FIG. 3 is a perspective view showing an insertion portion of an external conductor in the power supply terminal block in FIG.
FIG. 4 is a perspective view showing a temperature switch in the power supply terminal block in FIG.

In the power supply terminal block of the present invention, at least four substantially U-shaped portions are provided on the conductive fusible body of the current fuse, the temperature at the center thereof is the highest, and the temperature gradient at the substantially U-shaped portion is reduced. I'm making it big. The substantially U-shaped portion prevents the heat deformation direction from being limited to only one direction.

FIGS. 1 to 4 are circuit diagrams using a power supply terminal block 1 according to an embodiment of the present invention. The terminal block 1 is provided with one end of two power supply lines from a power supply 2 at intervals. Insulating resin 5 which is softened by the heat generated at the time of defective connection and can flow in is fixed between electrode plates 4a and 4b connected to these two external conductors (conductors) 3a and 3b. Current fuse 6 is connected to the electrode plates 4a and 4b.
Further, a circuit of a temperature switch 10 composed of a heat-fusible insulator 9 sandwiched between a conductor 7 and a conductor 8 which are normally insulated is formed at the tip of the current fuse 6. 1a is a lid of the power supply terminal block 1.

Conventionally, as shown in FIG. 5, a current fuse in a power supply terminal block has a current fuse blown at a finite set current value, and a load operated by a power supply and a power supplied from the power supply, for example, It is incorporated in a power supply terminal block provided between the lighting devices S1 to S4 and the like. When an excessive current flows due to a load abnormality or the like, the temperature is raised by Joule heat in the conductive fusible body. The current path is cut off by physical phenomena such as softening and melting.

However, in order to prevent an accident due to an overcurrent at an early stage, a fuse that can be blown at a low set current value is required. Therefore, the length L of the current fuse in the current direction is long, and the current flows. In the cross-sectional area perpendicular to the direction, the width w must be thin and the thickness t must be thin, but these all greatly reduce the rigidity of the conductive fusible just before fusing, and the softened fusible However, the power supply terminal block could not be made compact because of contact.

Therefore, according to the present invention, the conductive fusible body of the current fuse is configured to have at least four substantially U-shaped portions. Here, the operation of the case where there are four substantially U-shaped portions according to FIG. 2 will be described in detail.

When an excessive current flows, the middle between the second and third substantially U-shaped portions U2 and U3 is the center of the conductive fusible material, and the temperature rises most by Joule heat. If the softening temperature of the conductive fusible material is exceeded, the third substantially U-shaped portion U3 is deformed in the depth direction if the second substantially U-shaped portion U2 is deformed in the direction perpendicular to the plane of the drawing due to symmetry. Since there are two substantially U-shaped portions from the center of the conductive fusible body to the conductor connecting portions 5a ₁ and 5a ₂ , the conductor connecting portions 5a ₁ to 5a 1
Th fusible element from a substantially U-shaped portion U1 or fourth substantially U-shaped portion U4, to the other conductor connecting portion 5a ₂ does not rise the temperature enough to soften, it serves to apply a force or prevent withdrawal force the deformation do. Therefore, the sag is suppressed by the action of the force until the deformed portion is blown, and the fusing is completed. In addition, since there are four substantially U-shaped portions, even when the temperature of the center of the conductive fusible body rises abnormally due to Joule heat due to an overcurrent, the conductor connection portion 5a _{1 is} suddenly changed by the substantially U-shaped portion. , 5a ₂ can hold the temperature never fusible deforms. For this reason, in the present embodiment, the fusible body from the conductor connection portion (current fuse end portion) to the substantially U-shaped portion can further increase the overall length while suppressing thermal deformation of the central portion. Thus, the set fusing current value can be reduced and the size can be reduced.

If a tensile stress is applied to the conductive fusible material in advance, the substantially U-shaped portion is pulled by the two conductor connecting portions, so that dripping can be further suppressed. Thereby, the substantially U-shaped portion may be opened at a wide angle. Alternatively, by forming at least one place where the substantially U-shaped portion of the conductive fusible body is opened at a wide angle in advance, contact between the conductive fusible bodies during thermal deformation can be prevented. Can be suppressed. The distance L ₂₃ of a substantially U-shaped section U2 and U3
Substantially is made smaller than the distance L ₃₄ in the U-shaped portion U1 and distance L ₁₂ and a substantially U-shaped section U3 and U4 of U2 is an area where the temperature is raised to the softening is reduced, the rigidity of a substantially U-shaped portion U1 and U2 Accordingly, the rotational moment generated when the substantially U-shaped portions U2 and U3 are thermally deformed can be suppressed, and the deformation can be minimized.

Embodiment 2 In the present invention, in order to cut off the current supply to the primary side current supply line arranged in series, an insulating resin whose viscosity suddenly decreases at 100 ° C. or more is inserted into the insertion portion of the external conductor. Alternatively, when the insulating resin is softened at the set temperature, it flows into the space between the external conductor and the electrode plate to form a complete insulating layer. As shown in FIG. 3, an insulating resin 5 whose viscosity rapidly decreases at 100 ° C. or more is fixed to the external conductor insertion portion 11 into the power terminal block 1 and the electrode plate 4a in the power terminal block 1. Examples of the insulating resin 5 having such properties include pine-based wax. The viscosity of the insulating resin 5 is preferably 100 ° C. or more and 100 cp or less in order to secure optimal fluidity.

In this case, according to FIG. 3, insulating resin 5 is fixed to two portions of the power supply terminal block 1 or the external conductor insertion portion 11 into the equipment main body and the power supply terminal block 1 or the electrode plate 4a of the equipment main body. The details of the operation in the case will be described.

External conductor insertion portion 11 of power supply terminal block 1
For example, an arc is generated between the external conductor 3a and the electrode plate 4a, and the insulating resin 5 is softened and liquefied when the temperature of the external conductor 3a rises. ) Flows into the slight gap of the electrode plate 4a along the external conductor 3a. As a result, since the insulating layer is formed, the current supply is immediately stopped. When the direction of the gravitational force is opposite, the insulating resin fixed on the electrode plate side similarly flows along the electrode plate and flows into a slight gap between the external conductor and the electrode plate.

In the present embodiment, the supply of power to the primary power supply line is stopped when the insulating resin, for example, wax, fixed near the electrode plate of the power supply terminal block is in contact with the external conductor and the electrode plate. When the temperature of the external conductor and the electrode plate rises, the viscosity sharply drops due to the arc that is blown when the electric current is conducted, so that the wax flows into the incompletely contacting state and forms an insulating layer. As a result, the power supply to the load as well as the primary power supply line can be stopped.

Embodiment 3 In this embodiment, as a temperature switch that operates at the time of abnormal temperature rise, a heat-meltable insulator having a softening start temperature higher than 90 ° C. is arranged between metal plates, and a quick response is provided. For this purpose, a compressive stress is applied to the heat-fusible insulator between the metal plates. At this time, the response time can be controlled by providing a protrusion on one of the metal plates so that the distance between the protrusion and the other metal plate can be arbitrarily adjusted.

As shown in FIGS. 1 and 4, the temperature switch 10 using the heat-meltable insulator 9 provided in the power supply terminal block 1 has a function of cutting off the current from other circuits when an arc is generated. Will be described in detail.

First, if there is no abnormality in the power supply terminal block 1, the external conductor 3a is connected to the electrode plate 4a, and power is supplied to the load circuit via the current fuse 6. However, the power terminal block 1
If the external conductor is not completely inserted into the power supply terminal block 1, the temperature of the external conductor 3a and the temperature of the electrode plate 4a increase, and the temperature in the power supply terminal block 1 increases. The heat-meltable insulator 9 which is a flame-retardant material having a melting point of 90 ° C. or higher or to which the flame-retardant material is added softens. At this time, the conductor 8 is set so as to come to the heat source side, and the heat-meltable insulator 9 in contact with the conductor 8 softens and liquefies, and enters the hole 12 having a smaller diameter than the insulator 9. , The conductor 7 and the conductor 8 come into contact with each other via the conductive projection 13 which is the same member. As a result, a short circuit that does not include a load is formed, so that an excessive current flows through the current fuse 6 and the power supply to the load is stopped instantaneously. Accordingly, no short-circuit current is supplied to the load, so that it is possible to prevent the accident from spreading.

The conductor 7 and the conductor 8 are preferably arranged so that a compressive stress is applied to the heat-meltable insulator 9. Since such compressive stress acts, the heat-fusible insulator does not separate due to vibration during transportation or installation work.

In the present embodiment, the temperature switch of the power supply terminal block is constituted by a heat-meltable insulator having a softening temperature of 90 ° C. or higher applied with compressive stress by two metal plates. Is softened, the insulator is extruded into a small hole provided in the metal plate, the gap between the metal plates is reduced, and the two metal plates are surely brought into contact by the protrusion provided on one of the metal plates. Can be.

In this embodiment, the temperature switch composed of a heat-fusible insulator sandwiched between a conductor having only a projection and a conductor having only a hole has been described. The same effect as in the present embodiment can be obtained even with a temperature switch having Also, protrusions, holes,
Needless to say, the same effect can be obtained when a plurality of heat-fusible insulators are provided. Furthermore, in the present embodiment, an example in which a conductor having a hole is disposed on the heat source side has been described. However, since the temperature inside the power supply terminal block becomes substantially uniform as the temperature becomes higher, the hole is disposed on the side not on the heat source side. The same effect can be obtained even if a conductor provided with a.

Embodiment 4 In the above-described embodiment, the current fuse made of a conductive fusible material having a constant line width has been described. By increasing the resistance, high Joule heat can be locally generated to speed up the fusing. For example, a similar effect can be obtained even if a notch is provided.

Fifth Embodiment In the above-described embodiment, a current fuse made of a single conductive fusible material has been described. However, the vicinity of the center of the conductive fusible material is coated with a low thermal conductive material so that Joule heat can be reduced. Dispersion can be suppressed and fusing can be achieved early by locally increasing the temperature.

In the case of the power supply terminal block in which the current fuse 6 and the temperature switch 10 are arranged, if the temperature reaches a preset melting point of the insulating resin for some reason, the heat-meltable insulator 9 of the temperature switch 10 is turned on. After melting, the heat-fusible insulator 9 cannot keep the interval between the two conductors 7 and 8 and comes into contact with each other, so that an excessive current flows instantaneously. This excessive current blows the current fuse 6 and opens the load circuit. For this reason, a load device, for example, a lighting device, suddenly turns off, and an abnormality can be noticed.

The current fuse 6 and the temperature switch 1
Also in the case of the power supply terminal block in which 0 and the insulating resin 5 are arranged, similarly to the above-described embodiment, the load device, for example, the lighting equipment can be turned off suddenly and an abnormality can be noticed.

In the above-described embodiment, the description has been given of the current fuse installed on the load side. However, the current fuse may be installed on the primary side of the power supply. In this case, the same effects as in the above embodiment can be obtained.

[0046]

As described above, according to the first aspect of the present invention, since at least four substantially U-shaped portions are provided in the conductive fusible body of the current fuse, a long electric circuit is installed in a small space to set and blow. A current value can be reduced, and a power supply terminal block having a current fuse that can be stored in a small space can be obtained.

According to the second aspect of the present invention, the tensile stress is applied to the conductive fusible material in a state where the conductive fusible material is electrically connected to another conductor on the current path. The sag can be prevented by the action of stress even at the time of softening immediately before fusing, and the fusing can be performed safely without contacting the container of the power terminal block.

According to the third aspect of the present invention, there is at least one location where the substantially U-shaped portion of the conductive fusible material is opened at a wide angle, so that the fusible material is deformed beyond the softening temperature. When starting, the fusible body itself can be prevented from contacting.

According to the fourth aspect of the invention, since the metal cross-sectional area perpendicular to the direction of the current flowing through the conductive fusible material is partially reduced, high Joule heat can be obtained by partially increasing the resistance. It can be generated locally to speed up fusing.

According to the fifth aspect of the present invention, the conductive fusible material is partially coated with a low thermal conductive material,
As the material composition is not uniform, the dissipation of Joule heat is suppressed,
By locally increasing the temperature, the fusing can be performed early.

According to the sixth aspect of the invention, since the interval between the substantially U-shaped portions of the conductive fusible member is not constant, the rotational moment generated at the time of thermal deformation can be reduced.

According to the seventh aspect of the present invention, the conductive fusible element is blown to protect the load when a current equal to or larger than a set current value is supplied on the current supply path from the power supply to the load. At the same time, since the fuse is blown by forming a short circuit that does not pass through the load even when abnormal heat is generated, accidents due to overcurrent and abnormal heat can be completely prevented at an early stage.

According to the invention according to claim 8, the insulating resin softened by the heat of the arc generated when the contact between the external conductor from the power supply and the electrode plate of the power terminal block is incomplete is made of the insulating resin of the external conductor. Since the insulating resin is fixed near the insertion portion or the electrode plate, the insulating resin flows between the external conductor and the electrode plate when the insertion of the external conductor is incomplete and forms an insulating film. Can be turned off.

According to the ninth aspect of the present invention, since the insulating resin softened by abnormal heating due to the poor contact of the external conductor is added with a flame retardant material, the reliability can be improved.

According to the tenth aspect of the present invention, the insulating resin which is softened by abnormal heating due to poor contact of the external conductor is in contact with either the conductor or the electrode plate in a solid state. When the insertion of the external conductor is incomplete, the current flowing through the power supply line on the primary side can be cut off by flowing the gap between the external conductor and the electrode plate to form an insulating film.

According to the eleventh aspect of the present invention, the insulating resin softened by abnormal heating due to poor contact of the external conductor has a viscosity of 100 cp or less at 100 ° C. or higher. It is transmitted to the electrode plate and flows between the conductive wire and the electrode plate, so that the insulating film can be surely formed.

According to the twelfth aspect of the present invention, there are provided two conductive metal plates and a hot-melt insulator sandwiched between the metal plates and softened at a finite set temperature value. Since one of the conductive metal plates is provided with a temperature switch having a protruding portion that makes conductive contact when the heat-meltable insulator is softened, the conductive portion can be reliably conducted at the protruding portion of the conductor.

According to the thirteenth aspect of the present invention, since at least one of the conductive metal plates has a hole into which the softened heat-meltable insulator melts, the insulator is set at a predetermined temperature. When softened in step (2), the material melts into the hole and can be reliably conducted at the projecting portion of the conductor.

According to the fourteenth aspect of the present invention, since the conductive metal plate provided with the holes is the side of the metal plate having a temperature increasing factor, the insulator softens at a preset temperature. Occasionally, the conductive material melts into the hole and can be reliably conducted at the projecting portion of the conductor.

According to the fifteenth aspect of the present invention, since the heat-fusible insulator contains a flame-retardant material or a flame-retardant material, the flame retardancy of the insulator can be improved.

According to the invention of claim 16, since the compressive stress is applied to the heat-fusible insulator by the two conductive metal plates, the compressive stress is applied by the conductor having the projection and the hole. When the insulator is softened at a preset temperature, the insulator melts into the hole and the projection can be reliably conducted.

[Brief description of the drawings]

FIG. 1 is a developed view of a circuit showing an embodiment of a power supply terminal block of the present invention.

FIG. 2 is a shape diagram showing a current fuse in a power supply terminal block in FIG. 1;

FIG. 3 is a perspective view showing an insertion portion of an external conductor in a power supply terminal block in FIG. 1 and an insulating resin fixed near an electrode plate.

FIG. 4 is a perspective view showing a temperature switch in a power supply terminal block in FIG. 1;

FIG. 5 is a perspective view showing an example of a conventional current fuse.

[Explanation of symbols]

1 power supply terminal block, 1a cover of power supply terminal block, 2 power supply, 3
a, 3b outer conductor, 4 temperature switch, 4a, 4b
Electrode plate, 5 an insulating _resin, 5a 1, 5a ₂ conductor connection portion, 6 a current fuse, 7,8 conductor 9 thermofusible insulator 10 temperature switches, 11 external conductor insertion section 1
2 holes, 13 protrusions.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H02H 3/08 H02H 3/08 P (72) Inventor Toshihisa 2-3-2 Marunouchi 2-chome, Chiyoda-ku, Tokyo Inside the company (72) Inventor Hideaki Saito 5-1-1, Ofuna, Kamakura-shi, Kanagawa Prefecture Inside Mitsubishi Electric Lighting Co., Ltd. (72) Inventor Makoto Hashimoto 5-1-1, Ofuna, Kamakura-shi, Kanagawa Prefecture Inside Mitsubishi Electric Lighting Co., Ltd.

Claims (16)

[Claims] 1. A conductive fusible member which is connected on an energizing path to a load side supplied from a power supply and is blown at a finite set current value, wherein the conductive fusible member has at least four U-shaped portions. A power terminal block comprising a current fuse having a plurality of current fuses. 2. The power supply terminal block according to claim 1, wherein a tensile stress is applied to the conductive fusible material in a state where the conductive fusible material is electrically connected to another conductor on the current path. 3. The power supply terminal block according to claim 1, wherein there is at least one location where the substantially U-shaped portion of the conductive fusible body is opened at a wide angle. 4. The power supply terminal block according to claim 1, wherein a metal cross-sectional area perpendicular to a direction of a current flowing through the conductive fusible member is partially reduced. 5. The power supply terminal block according to claim 1, wherein the conductive fusible member is partially coated with a low thermal conductive material. 6. The conductive fusible body according to claim 1, wherein a distance between two U-shaped central portions is shorter than that between any other adjacent U-shaped combinations. Power terminal block. 7. The conductive fusible body is blown for protection of a load when a current of a set current value or more is supplied on a current supply path from a power supply to a load side, and the load is also applied when abnormal heat is generated. The power supply terminal block according to any one of claims 1 to 6, wherein fusing is performed by forming a short circuit that does not pass. 8. An insulating resin softened by the heat of an arc generated when contact between an external conductor from a power supply and an electrode plate of a power supply terminal block is incomplete, is fixed to an insertion portion of the external conductor or in the vicinity of the electrode plate. Power supply terminal block characterized by being done. 9. The power supply terminal block according to claim 8, wherein a flame-retardant material is added to the insulating resin that is softened by abnormal heating due to poor contact of the external conductor. 10. The insulating resin softened by abnormal heating due to poor contact of the external conductor, in a solid state, is in contact with either the insertion portion of the external conductor or the electrode plate. 9. The power supply terminal block according to 9. 11. The power supply terminal according to claim 8, wherein the insulating resin softened by abnormal heating due to the bad contact of the external conductor has a viscosity of 100 cp or less at 100 ° C. or higher. Stand. 12. A heat-meltable insulator sandwiched between two conductive metal plates and softened at a finite set temperature value, and is provided on at least one of the metal plates. A power supply terminal block comprising: a temperature switch having a protruding portion that makes conductive contact when the heat-fusible insulator is softened. 13. The power supply terminal block according to claim 12, wherein at least one of the conductive metal plates has a hole into which the softened heat-meltable insulator melts. 14. The conductive metal plate provided with the holes,
14. The power supply terminal block according to claim 12, wherein the power supply terminal block is a metal plate side having a factor that causes a temperature rise. 15. The power supply terminal block according to claim 12, wherein the heat-fusible insulator includes a flame-retardant material or a flame-retardant material. 16. The power terminal block according to claim 12, wherein a compressive stress is applied to the heat-fusible insulator by two conductive metal plates.