JP2559661Y2 - Positive characteristic thermistor device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive temperature coefficient thermistor device used for preventing freezing of a refrigerator door or a water pipe, and more particularly to improvement of an overcurrent fusing portion.

[0002]

2. Description of the Related Art A PTC thermistor has been conventionally used as a heater. A heater using a PTC thermistor device as a heat source operates as a constant-temperature heating element. Therefore, unlike a heater using a resistance heating element such as a nichrome wire or a sheathed heater as a heat source, the danger of overheating is safe to cry. However, when the positive temperature coefficient thermistor is deteriorated, an overcurrent flows at the time of thermal equilibrium, which is originally a low current, and there is a danger that the positive temperature coefficient thermistor may be damaged, abnormally heated, and a fire may be caused. As a means for preventing such an abnormal failure, a technique of providing a narrow portion serving as an overcurrent fusing portion on an electrode plate is known. As prior art documents, there is Japanese Utility Model Laid-Open No. 55304/1987.

[0003]

Since the overcurrent fusing portion is provided as a narrow portion on a part of the electrode plate made of a thin metal plate, the overcurrent fusing portion has low mechanical strength and is easily broken at the time of assembly or the like. If the thickness of the electrode plate is increased, the mechanical strength of the narrow portion can be increased. However, in this case, the fusing current value increases, and the overcurrent protection effect decreases. The above-mentioned prior art documents do not disclose any means for solving these problems.

Accordingly, an object of the present invention is to provide a PTC thermistor device capable of reliably preventing a narrow portion serving as an overcurrent fusing portion from being damaged even when a high overcurrent protection effect is secured by using a thin electrode plate. It is to be.

[0005]

In order to solve the above-mentioned problems, the present invention provides a positive temperature coefficient thermistor device having a positive temperature coefficient thermistor, an electrode plate, a support, and an insulating sheath. The thermistor has electrodes on both main surfaces facing each other, the electrode plate includes two electrode plates, each of the electrode plates is formed of a thin metal plate, an electrode contact portion, and an extraction terminal portion. Wherein the electrode contact portion is in contact with the electrode of the positive temperature coefficient thermistor, the lead terminal portion is continuous with the electrode contact portion, and at least one of the electrode plates is a lead terminal from the electrode contact portion. Having a narrow portion serving as an overcurrent fusing portion in the middle of the path leading to the portion, and having a concave portion or a convex portion on both sides of the narrow portion, the support is made of an electrically insulating material, Arranged between the electrode plates on the lead terminal side And has a plurality of convex portions or concave portions on at least one surface side, each of the convex portions or concave portions is inserted into the concave portion or convex portion of the electrode plate, the insulating exterior body, the positive characteristic thermistor, The electrode plate and the support are covered.

[0006]

Each of the electrode plates is made of a thin metal plate, the electrode contact portion is in contact with the electrode of the positive temperature coefficient thermistor, the lead terminal portion is continuous with the electrode contact portion, and at least one of the electrode plates is at the electrode contact portion. Has a narrow portion that becomes an overcurrent fusing portion in the middle of the path from the lead to the lead terminal portion. If the PTC thermistor deteriorates and an overcurrent flows, the narrow portion is blown and an overcurrent protection effect is obtained. . As a result, breakage of the positive temperature coefficient thermistor, abnormal heat generation, fire due to the heat generation, and the like are reliably prevented.

At least one of the electrode plates has a concave portion or a convex portion on both sides of the narrow portion, and the support is disposed between the electrode plates on the side of the lead-out terminal portion, and a plurality of convex portions are provided on at least one surface side. Or a concave portion, and each of the convex portions or the concave portions is inserted into the concave portion or the convex portion of the electrode plate. Therefore, the concave portion or the convex portion provided on the electrode plate, and the convex portion or the concave portion provided on the support body. The electrode plate is supported and positioned by the support by the concave and convex fitting. For this reason, breakage, breakage, and the like of the narrow portion at the time of assembly can be reliably prevented.

[0008] Since the narrow portion is protected by the support and positioning action by the concave and convex fitting, the thickness of the electrode plate can be kept thin. For this reason, a thin electrode plate can be used, and a high overcurrent protection effect can be secured.

[0009]

FIG. 1 is an exploded perspective view of a PTC thermistor device according to the present invention, FIG. 2 is a plan partial sectional view, FIG. 3 is a front partial sectional view, and FIG. 4 is a bottom partial sectional view. 1 is a positive temperature coefficient thermistor, 2 and 3 are electrode plates, 4 is a support, and 5 is an insulating sheath. Reference numeral 6 denotes an insulating filler, and reference numerals 7 and 8 denote lead wires.

The PTC thermistor 1 has electrodes 11 and 12 on both opposing main surfaces. Positive characteristic thermistor 1 shown
May be disk-shaped or square-plate-shaped.

Each of the electrode plates 2 and 3 is made of a thin metal plate such as stainless steel or phosphor bronze. The metal materials constituting the electrode plates 2 and 3 may be the same or different. Further, the plate thicknesses may be the same or different. Each of the electrode plates 2 and 3 is
Electrode contact portions 21 and 31 and lead terminal portions 22 and 32 are provided. The electrode contact portions 21 and 31 contact the electrodes 11 and 12 of the positive temperature coefficient thermistor 1, and the lead terminal portions 22 and 32 are connected to the electrode contact portions 21. , 32 respectively.

Among the electrode plates 2 and 3, the electrode plate 2 has a narrow portion 23 serving as an overcurrent fusing portion in the middle of the path from the electrode contact portion 21 to the lead terminal portion 22. It has recesses 24, 25 by holes on both sides. The narrow portion 23 is formed so as to be recessed in the middle (in FIG. 1).
The recesses 24 and 25 may be slits or recesses recessed from one surface side to the other surface side. Also, a convex portion can be used instead of the concave portion. The illustrated recesses 24, 2
5 has slits 26 and 27 around the hole, and the slits 26 and 27 secure spring properties.

The support 4 is made of an electrically insulating material such as plastic or ceramic having excellent heat resistance, and is disposed between the electrode plates 2-3 on the side of the lead terminals 22 and 32. On at least one surface side, a plurality of convex portions 4
1 and 42, and the convex portions 41 and 42 are fitted and inserted into the concave portions 24 and 25 of the electrode plates 2 and 3, respectively. When the concave portions 24 and 25 of the electrode plate 2 are convex portions, the convex portions 41 and 42 of the support 4 are provided as concave portions.

The insulating sheath 5 covers the PTC thermistor 1, the electrode plates 2, 3 and the support 4. The insulating sheath 5 is made of ceramic or heat-resistant plastic. The illustrated insulating casing 5 is shaped like a case, and has an opening 52 on one side end face of the main housing 51, and the opening 5
In this structure, the positive temperature coefficient thermistor 1, the electrode plates 2, 3 and the support 4 are inserted into the main housing 51 from the second side. The opening 52 is sealed with the insulating filler 6. This ensures moisture resistance and prevents harmful liquids, gases, and the like from entering the main storage portion 51. Instead of using a case, a structure in which the whole is covered with an insulating resin may be used.

As described above, each of the electrode plates 2 and 3 has the electrode contact portions 21 and 31 in contact with the electrodes 11 and 12 of the positive temperature coefficient thermistor 1, and the extraction terminal portions 22 and 32 have the electrode contact portions 21 and 31. And the electrode plate 2 is
Since a narrow portion 23 serving as an overcurrent fusing portion is provided in the middle of the path from the first terminal 31 to the lead terminal portions 22 and 32, when the positive characteristic thermistor 1 is deteriorated and an overcurrent flows, the narrow portion 23 is provided.
Melts, and an overcurrent protection action is obtained. As a result, breakage of the positive temperature coefficient thermistor 1, abnormal heat generation, fire due to the heat generation, and the like are reliably prevented.

The electrode plate 2 has concave portions 24 and 25 on both sides of the narrow portion 23.
2 and 32, are disposed between the electrode plates 2-3 and have a plurality of convex portions 41 and 42 on at least one surface side.
42 are inserted into the concave portions or convex portions of the electrode plates 2 and 3, the concave portions 24 provided on the electrode plates 2 and 3
The electrode plates 2 and 3 are supported and positioned by the support 4 by the uneven connection between the projections 41 and 42 provided on the support 4. For this reason, breakage, breakage, and the like of the narrow portion 23 serving as the overcurrent fusing portion can be reliably prevented.

In addition, since the narrow portion 23 is protected by the support and positioning action by the concave and convex fitting, the thickness of the electrode plate 2 can be kept thin. Therefore, a high overcurrent protection effect can be ensured by using the thin electrode plate 2.

In the embodiment, the support 4 has a narrow portion 23.
And a recess 43 for accommodating the same. The narrow portion 23 is disposed in the space of the concave groove 43 in a state of hanging fishing. With such a structure, overcurrent fusing of the narrow portion 23 is performed inside the concave groove 43 and does not fly outside, so that electrical and mechanical obstacles due to fusing droplets can be avoided.

The support 4 further has another groove 44 (see FIG. 3) for guiding the groove 43 to the outside. With such a structure, the air expanded by the heat when the narrow portion 23 is blown by the overcurrent is released to the outside through the concave groove 44. For this reason, mechanical due to air expansion during overcurrent fusing,
Electrical failure can be avoided.

The electrode plate 3 has a spring portion 33, and the spring portion 3
3 is arranged on the opposite side of the electrode contact portion 31 from the electrode contact surface. In the assembled state, the spring part 33 is
Spring contact with the inner wall surface 53 of the
Apply spring pressure to press. With such a structure, the electrode contact portion 31 of the electrode plate 3 comes into surface contact with the electrode 12 of the PTC thermistor 1, so that the contact between the electrode plate 3 and the PTC thermistor 1 is stabilized. Further, the electrode plate 3 has a concave portion 34 formed by a hole in its surface, and a convex portion 45 (see FIG. 3) provided on the support 4 is fitted into the concave portion 34 for positioning.

The insulating sheath 5 has a mouth shape in which an opening 52 is unfolded. And the unfolded step 5
4, the support 4 is positioned, and an insulating filler 6 is filled behind the support. With such a step structure,
Since the insulative filler 6 can be prevented from flowing into the main storage portion 51, poor electrical contact due to the insulative insulant 6 and a decrease in the overcurrent fusing function can be prevented.

The lead wires 7 and 8 have conductor portions 71 and 81 connected to lead terminal portions 22 and 32 inside the insulating filler 6, respectively.
The insulating coatings 72, 82 are located inside the insulating filling 6. When the conductor portions 71 and 81 are connected to the lead terminal portions 22 and 32 inside the insulating filler 6, the lead terminal portions 22 and 32 are connected.
The mechanical strength of the lead wires 7 and 8 with respect to
Can be increased by Insulation coating parts 72, 8
When 2 is located inside the insulating filler 6, the insulating filler 6 comes into close contact with the insulating coating portions 72 and 82, the sealing property at the interface between them is increased, and the intrusion of harmful liquid or gas is prevented. The lead wires 7, 8 are arranged at the center of the opening. Thereby, the insulating filler 6 is sufficiently filled, and the sealing property is improved. In addition to the drawing structure shown in the figure, a structure in which the drawing terminal portions 22 and 32 of the electrode plates 2 and 3 are led out of the insulating filler may be adopted.

[0023]

As described above, according to the present invention, the following effects can be obtained. (A) Each of the electrode plates is made of a thin metal plate, an electrode contact portion is in contact with an electrode of the positive temperature coefficient thermistor, a lead terminal portion is continuous with the electrode contact portion, and at least one of the electrode plates is an electrode contact portion. Has a narrow portion that serves as an overcurrent fusing portion in the middle of the path from the lead to the lead terminal, so that the overcurrent protection effect of the narrow portion can be obtained, thereby damaging the PTC thermistor, causing abnormal heat generation, and causing a fire, etc. Can be provided. (B) At least one of the electrode plates has a concave portion or a convex portion on both sides of the narrow portion, and the support is disposed between the electrode plates on the lead terminal portion side, and a plurality of convex portions is provided on at least one surface side. Or having a concave portion, since each of the convex portion or the concave portion is inserted into the concave portion or the convex portion of the electrode plate, the electrode plate is supported by the support by the concave and convex fitting, is positioned,
A positive temperature coefficient thermistor device that can reliably prevent breakage, breakage, and the like of the narrow portion during assembly can be provided. (C) Since the narrow portion is protected by the support and positioning action by the concave and convex fitting, a positive temperature coefficient thermistor device having a high overcurrent protection action using a thin electrode plate can be provided.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a positive temperature coefficient thermistor device according to the present invention.

FIG. 2 is a plan partial sectional view of the positive temperature coefficient thermistor device shown in FIG. 1;

FIG. 3 is a partial front sectional view of the positive temperature coefficient thermistor device shown in FIG. 1;

FIG. 4 is a bottom partial sectional view of the positive temperature coefficient thermistor device shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive temperature coefficient thermistor 2, 3 Electrode plate 21, 31 Electrode contact part 22, 32 Outgoing terminal part 24, 25 Concave part 4 Support body 41, 42 Convex part 5 Insulation exterior body

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Nohara 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References Japanese Utility Model Sho-62-163852 (JP, U) Japanese Utility Model Sho-62 −55304 (JP, U)

Claims (3)

(57) [Scope of request for utility model registration] 1. A positive temperature coefficient thermistor device comprising a positive temperature coefficient thermistor, an electrode plate, a support, and an insulating sheath, wherein said positive temperature coefficient thermistor has electrodes on opposite main surfaces. The electrode plate includes two electrode plates, each of the electrode plates is made of a thin metal plate, has an electrode contact portion, and a lead terminal portion, and the electrode contact portion is a positive temperature coefficient thermistor. A narrow width that is in contact with the electrode, the extraction terminal portion is continuous with the electrode contact portion, and at least one of the electrode plates becomes an overcurrent fusing portion in a path from the electrode contact portion to the extraction terminal portion. The support has a concave portion or a convex portion on both sides of the narrow portion, and the support is made of an electrically insulating material, and is disposed between the electrode plates on the lead terminal portion side and the electrode is provided. Support the plate and make at least one side A plurality of convex portions or concave portions, each of which is inserted into the concave portion or convex portion of the electrode plate, wherein the insulating exterior body includes the positive temperature coefficient thermistor, the electrode plate, and the support. Positive temperature coefficient thermistor device covering the body. 2. The method according to claim 1, wherein the support has a groove for accommodating the narrow portion, and the narrow portion is arranged in the space of the groove in a fishing state. The described positive characteristic thermistor device. 3. The positive electrode according to claim 1, wherein at least one of the electrode plates has a spring portion, and the spring portion is disposed on a side of the electrode contact portion opposite to an electrode contact surface. Characteristic thermistor device.