JPH10149873A - Positive-characteristic thermistor heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and lightweight positive-characteristic thermistor heating element having good heating efficiency and an excellent radiation effect and suitable for an automobile heater. SOLUTION: The outer periphery section of a positive-characteristic thermistor element 1 applied with electrodes on both faces of a disk-like or angular plate-like barium titanate-based semiconductor porcelain having a constant thickness and many through holes 2 is pinched by the center opening edge sections of two frame-like terminal boards 3 having many ventilation/radiation holes 6 in the sandwich state, and the outer periphery sections of two frame-like terminal boards 3 are pinched by insulating pinch bodies 12 in pressure contact.

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 heating element which is compact and lightweight, has good heat generation efficiency and excellent heat dissipation effect, and is suitable for a heater for an automobile.

[0002]

2. Description of the Related Art Conventionally, a positive temperature coefficient thermistor (hereinafter referred to as "PT
Japanese Patent Application Laid-Open No. S57-57157) describes a heating element using an element.
There are those disclosed in JP-A-112185 and JP-A-58-101490.

[0003] In the device disclosed in Japanese Patent Application Laid-Open No. 57-112185, an electrode such as aluminum sprayed is provided on the largest opposing surface of a thin (strip-shaped) PTC element, and this electrode surface is formed of aluminum. The radiating fins are fixed with conductive adhesive, and after connecting a copper wire to a part of the radiating fins by welding or soldering, etc., the whole is covered with unsaturated polyester resin etc. An insulation protection case that also functions as a cover and a heat radiation fin protection case is integrally formed.

[0004] Japanese Unexamined Utility Model Publication No. 58-101490 discloses a radiator fin having both sides of a PTC element having a large number of through holes and electrodes having a through hole having the same shape as the through holes. They are tightly fixed so that the positions of the through holes coincide with each other.

[0005]

Problems to be Solved by the Invention
No. 85 discloses a technique in which heat generated by a PTC element is transmitted to radiation fins provided on both sides of the PTC element and then used as warm air, and a conductive material is used for electrical connection between the PTC element and the radiation fin. In addition to the above-mentioned adhesive, it is necessary to airtightly cover the entire periphery of the aluminum radiating fins including the connection terminals of the copper wires with the unsaturated polyester resin.

In the device disclosed in Japanese Utility Model Application Laid-Open No. 58-101490, a large number of through holes are provided in a PTC element itself, and two radiating fins which also serve as electrodes having the same size through holes at the same position are used. The PTC element is tightly fixed in a sandwich shape. Therefore, although the efficiency is good, the heat radiation effect is not considered to be good. Also, when the PTC element and both heat radiation fins are closely adhered and fixed, since the PTC element is a sintered body, it is difficult for the surfaces to match each other. In addition, there is a possibility that a stable conduction state may not be obtained, and furthermore, a complicated process is required, for example, a conductive adhesive is required for the close contact.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the conventional product, and does not directly contact an electrode plate or a heat sink on both surfaces of a PTC element having a large number of through holes. By sandwiching the outer peripheral portion of the PTC element in a sandwich shape with a conductive plate also serving as a terminal plate having a large number of ventilation holes for heat radiation, the PTC element is compact and lightweight, has good heat generation efficiency, and has a heat radiation effect. The present invention also provides a heating element using an excellent PTC element.

That is, a first aspect of the present invention is a PTC element 1 in which electrodes are provided on both surfaces of a disc-shaped or square-plate-shaped barium titanate-based semiconductor ceramic having a large number of through holes 2 and a constant thickness.
Is sandwiched between the central opening edges of two frame-shaped terminal plates 3 provided with a large number of ventilation and heat radiation holes 6, and the outer peripheral portions of the two terminal plates 3 are insulated. A positive-characteristic thermistor heating element characterized in that it is pressed and held by the holding tool 12.

A second aspect of the present invention is the positive temperature coefficient thermistor heating element according to the first aspect, wherein the ventilation / radiation hole 6 is provided over the entire outer periphery of the central opening edge of the frame-shaped terminal plate 3.

A third aspect of the present invention is the positive temperature coefficient thermistor according to the first aspect, wherein the ventilation and heat radiating holes 6 are provided above and below the central opening edge of the frame-shaped terminal plate 3 or on the left and right sides of the central opening edge. It is a heating element.

A fourth aspect of the present invention is the frame spring according to the first to third aspects, wherein the frame-shaped spring has a plurality of corrugated elastic portions 19 at a sandwiching contact portion between the outer peripheral portion of the PTC element 1 and the frame-shaped terminal plate 3. 17 is a positive-characteristic thermistor heating element interposed therebetween.

According to a fifth aspect of the present invention, in the fourth aspect, the frame-shaped spring 17 is a rectangular frame having the same shape as the outer peripheral portion of the rectangular plate-shaped PTC element 1, and the corrugated elastic portion 19 is provided at the center of each side. This is a positive temperature coefficient thermistor heating element in which slit-shaped notches 18 are provided inside the four corners toward the outer peripheral corners of the rectangular frame.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the insulating holding member 12 has at least two
This is a positive-characteristic thermistor heating element that is formed by joining two or more divided frame-shaped holding members 8 and 9 and combining them in a frame shape.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of the present invention, FIG. 2 is an enlarged sectional view taken along line AA of FIG. 1, and FIG. 3 is an enlarged sectional view taken along line BB of FIG.

In FIG. 1, reference numeral 1 denotes a sintered body having a thickness of about 5 mm, having a large number of through holes 2 on almost the entire surface, a width of about 35 mm,
This is a PTC element in which electrodes are provided by printing on both sides of a barium titanate-based semiconductor porcelain having a height of about 30 mm.

3 is stamped and formed by a press.
A 0.8mm thick brass terminal plate with a width of about 70mm and a height of about 52mm.
In addition to having a rectangular window 4 slightly smaller than the outer shape of the TC element 1, a shallow concave portion 5 is formed around the rectangular window 4, and a large number of ventilation / radiation holes (hereinafter simply “radiation holes”) are formed around the terminal plate 3.
6) and the terminal 7 is formed in a part of the outer peripheral edge so as to protrude.

Reference numerals 8 and 9 denote left and right divided frame-like holding members each having a Y-shaped cross section. The holding members 10 are formed of an insulating material, and are formed at opposing upper and lower ends. And locking claw 1
1 are engaged with each other to form a frame-shaped holding body 12, and the lower engaging portion also serves as a protective case 13 for the electric wire connection portion. Note that the engagement means of the divided frame-shaped holding members 8 and 9 is not limited to the illustrated form.

The protection case 13 is formed in a projecting shape at the center of the lower part of the holding body 12, and the electric wire 14 is connected to the terminal 7 in the protection case 13, and the connector 15 is provided at the tip thereof. Reference numeral 16 denotes a mounting foot for the PTC heating element.

FIG. 4 is an exploded view of a frame spring 17 made of a copper alloy used in the present invention. The frame spring 17 has slit-shaped cutouts 18 formed in four corners by punching a press to form a square frame-shaped outer peripheral corner. And at the same time, as shown in FIG.
The corrugated elastic portion 19 is integrally formed at the center of each side.

The width of the frame of the frame spring 17 is P
The width of the outer peripheral portion of the TC element 1 and the concave portion 5 at the center of the terminal plate 3 are about 3 mm, which are almost the same as the width of the pin, and the thickness is about 0.3 mm.

It is important that the frame-shaped spring 17 has a single frame shape without being divided. If the frame-shaped spring 17 is merely a frame-shaped member and the wave-shaped elastic portion 19 is formed on each side, the wave-shaped elastic portion is not used. When the 19 is pressed, the four corners are lifted, so that they do not function sufficiently as a spring. Therefore, by providing a relatively deep slit-shaped notch 18 in the four corners, the four corners in the frame-shaped spring 17 are absorbed. doing.

In the figure, reference numeral 20 denotes a projection for positioning. The projection 20 is fitted into a groove (not shown) provided at a corresponding position of the terminal plate 3 and assembled, thereby forming a frame-shaped spring 17. Is to be prevented from being displaced. The protrusion 20 and the groove on the terminal plate 3 side are not always necessary.

In assembling the heating element according to the present invention, the PTC element 1 is sandwiched between the two concave portions 5 formed on the inner peripheral edge of the square window 4 at the center of the two terminal plates 3 opposed to each other. The holding members 8, 9 each having a Y-shaped cross section and having a divided frame shape are fitted into the outer peripheral portion of the terminal plate 3 so as to abut against each other from the left and right, and the locking members formed on the upper and lower ends of the holding members 8, 9 respectively. By engaging the portion 10 with the locking claw 11, the entire outer peripheral portions of the two terminal plates 3 are pinched and fixed in a frame state.

In this state, the joint between the outer peripheral surface of the PTC element 1 and the periphery of the concave portion 5 of both terminal boards 3 is designed to be in uniform contact with each other. However, since the terminal plate 3 is formed by punching out a brass plate material by pressing, distortion is likely to occur at the time of handling or assembling, and the PTC element 1 itself is also a fired product, so that there is some variation in dimensional accuracy. Then, when assembled as a product, the PTC element 1
The degree of adhesion between the terminal board 3 and the terminal plate 3 is not always uniform, and the thermal balance is lost, resulting in thermal distortion, which sometimes results in a failure in a performance test.

Therefore, in the present invention, FIGS.
As shown in the figure, the pressure contact portion between the PTC element 1 and the terminal plate 3, that is, between one side of the outer peripheral portion of the PTC element 1 and the concave portion 5 formed on the inner peripheral edge of the square window 4 at the center of the terminal plate 3. As shown in FIGS. 4 and 5, the PTC element 1 and the terminal plates 3 on both sides thereof are sandwiched and pressed together with a thin frame-shaped spring 17 interposed therebetween, thereby obtaining a stable pressed state. ing.

That is, by interposing the frame-shaped spring 17 between the PTC element 1 and the terminal plate 3, it is possible to absorb the influence of the above-mentioned variation of each component.
A stable contact pressure is obtained and uniform heat exchange is possible.

The frame-shaped spring 17 is a PTC element 1
Although it may be disposed between the terminal plate 3 on both sides, it has been confirmed from experiments that a sufficient effect can be obtained on one side.

A plurality of springs may be arranged on each side between the PTC element 1 and the terminal plate 3.
The use of two frame-shaped springs facilitates manufacture, facilitates handling during assembly, and facilitates positioning, thereby improving work efficiency.

In the above embodiment, the PTC element 1
In the above description, one PTC element 1 is provided at the center of the terminal plate 3, but two PTC elements 1 are arranged in parallel as shown in FIG. In addition, two square windows 4 may be provided at the same time, a recess 5 may be provided around the two windows, and the heating element may be assembled in the same manner as described above.

In any of the above cases, the heat radiation holes 6 provided in the frame-shaped terminal plate 3 may be provided so as to surround the entire periphery of the frame-shaped terminal plate 3 as shown in FIG. As shown in FIG. 8, it may be provided only at the upper and lower portions of the square window 4 or not shown, but only at the left and right portions of the square window 4, and these are determined by the performance required of each heating element. is there.

[0031]

In the PCT heating element according to the present invention, when power is supplied to the two terminal plates 3, the central PTC element 1 generates heat. Heat is exchanged and it comes out as hot air.

At this time, the heat of the heated PTC element 1 is also transmitted to the terminal plate 3, so that the air passing through the large number of ventilation / radiation holes 6 of the terminal plate 3 is also heated, and a large air volume is obtained.

Conversely, in the case of stopping the heat generation by interrupting the power supply to the terminal plate 3, the heat radiation efficiency is promoted by the presence of the ventilation / radiation hole 6 in the outer peripheral portion of the terminal plate.

[0034]

The heating element according to the present invention is compact (thin) and lightweight because the terminal plate is formed in a frame shape surrounding the PTC element and a large number of ventilation and heat radiation holes are formed around the terminal plate. Therefore, heat generation efficiency is high (blowing amount is large) and heat radiation efficiency is also good.

Further, in the present invention, when the PTC element and the terminal plate are joined to each other, the frame-shaped spring is interposed and pressed and held, so that variations in each member are absorbed and a uniform pressed state is obtained. A heating element of uniform quality can be manufactured.

Therefore, it can be said that the heating element according to the present invention is suitable for a heater for an automobile which is required to be compact and lightweight.

[Brief description of the drawings]

FIG. 1 is a front view of the present invention.

FIG. 2 is an enlarged sectional view taken along line AA of FIG.

FIG. 3 is an enlarged sectional view taken along line BB of FIG. 1;

FIG. 4 is a front view of the frame spring.

FIG. 5 is a side view of the frame spring.

FIG. 6 is a plan view of FIG. 1;

FIG. 7 is a bottom view of FIG. 1;

FIG. 8 is a front view of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive-characteristic thermistor element 2 Through-hole 3 Frame-shaped terminal plate 4 Square window 5 Depression 6 Ventilation and heat-dissipating hole 7 Terminal 8.9 Clamping tool 10 Locking part 11 Locking claw 12 Clamping body 13 Protective case 17 Frame spring 18 Notch 19 corrugated elastic part 20 protruding part

Claims (6)

[Claims] 1. An outer peripheral portion of a positive temperature coefficient thermistor element 1 in which electrodes are provided on both surfaces of a disc-shaped or square plate-shaped barium titanate-based semiconductor porcelain having a constant thickness provided with a large number of through-holes 2 The two frame-shaped terminal plates 3 provided with the ventilation / radiation holes 6 are sandwiched between the central opening edges of the two frame-shaped terminal plates 3, and the outer peripheral portions of the two frame-shaped terminal plates 3 are insulated by an insulating holding body 12. A positive-characteristic thermistor heating element characterized by being pressed and held. 2. The PTC thermistor heating element according to claim 1, wherein the ventilation / radiation hole is provided over the entire outer periphery of the central opening edge of the frame-shaped terminal plate. 3. The positive temperature coefficient thermistor heating element according to claim 1, wherein the ventilation / radiation holes 6 are provided at upper and lower portions of a central opening edge of the frame-shaped terminal plate 3 or at left and right portions of the central opening edge. 4. A thin frame spring 17 having a plurality of corrugated elastic portions 19 is interposed between a peripheral portion of the positive temperature coefficient thermistor element 1 and a holding portion between the frame terminal plate 3. The positive temperature coefficient thermistor heating element according to any one of the above. 5. A frame-shaped spring 17 is a rectangular frame having the same shape as the outer peripheral portion of the square plate-shaped positive temperature coefficient thermistor element 1, provided with a corrugated elastic portion 19 at the center of each side, and slit-shaped inside four corners. The PTC thermistor heating element according to claim 4, wherein the notch (18) is provided toward an outer corner of the rectangular frame. 6. An insulating holding body 12 is formed by joining at least two divided frame-shaped holding members 8 and 9 having a Y-shaped cross section and combining them into a frame shape. The heating element according to claim 1, wherein the heating element is a positive temperature coefficient thermistor.