JPH01124993A - Heating element - Google Patents

Abstract

PURPOSE:To reduce deformation during working and to enable surer waterproofness so as to obtain a heating element having the aforesaid characteristics by connecting covering members by spot welding through a plurality of sinked members, and connecting even flange member at the peripheral edge. CONSTITUTION:A pair of covering materials 9, 10 are connected by spot welding through a plurality of sinked members 18 provided on respective flat members 15 in a spot manner such that the tip ends 17 of one covering member are in contact with the tip ends 17 of those 17 of the other, and mutually overlapped flange members 16, 16 are similarly connected by spot welding, where sealing conditions are obtained. It is thus possible to reduce thermal deformation, with heat applied upon working, being made as the minimum by using spot welding, and to give resistivity against thermal deformation by making the sinked members serve as reinforcing ribs. As a result, the deformation in machining the covering materials can be reduced, and also surer waterproofness is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Application of the Invention> The present invention relates to a waste heat element, particularly a heating element using a positive temperature coefficient heating element (hereinafter referred to as a PCT heating element).

<Prior art> Conventionally, this type of heating element was disclosed in Japanese Patent Application Laid-Open No. 62-2027.
4, Japanese Patent Application Laid-open No. 62-20275, etc., are known, but these include methods for transmitting the heat generated from the PTC heating element to the covering material as the final heat dissipation surface. The thermal conductivity and the electrical insulation between the electrode for the PTC heating element and the covering material were insufficient. Therefore, in order to improve these points, the present inventors first proposed Japanese Patent Application Laid-Open No. 62-197052.
This technique is disclosed in Japanese Patent Application No. 62-197053.

<Problems to be Solved by the Invention> However, although the previous technique by the present inventors had made some progress, there still remained room for improvement in several respects. One of these concerns a means for covering and sealing with a covering material, specifically a means for joining the covering material. In other words, in these conventional technologies, the covering material is joined with bolts and nuts, but in order to ensure waterproofness when the heating element is used for heating liquid, it is ultimately necessary to connect the covering material in some form. Because it is necessary to weld bolts and nuts, this welding causes large deformation of the sheathing material, which creates a space between the heat sink and the sheathing material, making it impossible to obtain the necessary thermal conductivity. That's a problem.

Therefore, this invention has improved thermal efficiency (thermal conductivity).
At the same time, it is an object of the present invention to provide a means for forming a heating element having more reliable waterproof properties.

<Means for solving the problem> As a means for achieving the above object, in this invention,
Electrodes and heat sinks for electrical insulation are laminated symmetrically on both sides of a plurality of positive temperature coefficient heating elements arranged in a flat plate,
In a heating element formed by covering and sealing this laminate with a covering material, the pair of covering materials are connected by spot welding through a plurality of indentations provided in spots in each, and The gist is that even the flange-like portions of the circumferential edges that overlap each other are connected by spot welding to achieve a seal.

In other words, by using spot welding, the heat applied during processing is minimized and thermal deformation is reduced, and on the other hand, the invagination part is reinforced by the intervention of the invagination part. By acting like a rib and providing resistance against thermal deformation, the deformation during processing of the covering material is reduced, and moreover, more reliable waterproofness is ensured.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.

This heating element 1 consists of a heating plate 5 formed by fitting a PTC heating element 4 into a mica plate 2 through a support hole 3, and carbon plate electrodes 6 and a heat sink 7 stacked symmetrically on both sides of the heating plate 5. This laminate 8 is sealed with a pair of covering materials 9 and 10 on the front and back sides.

The heat dissipation plate 7 is formed by a combination of a mica sheet 12 for electrical insulation and a carbon sheet 13 for thermal conduction, and the thickness of the mica sheet 12 is set to the minimum necessary for electrical insulation. is 3KV/1 minute voltage resistance and 1
The minimum thickness required to achieve insulation of 000 MΩ or more is 0.2 mm, and the carbon sheet 13
The thickness is 0, 1, which is a preferable thickness obtained experimentally.
~0.4 am. Here, the reason why such a thickness is preferable for the carbon sheet 13 is that it has flexibility that can follow the deformation of the covering material 9 and 10 caused by heat generation, etc., and that it can prevent the mica sheet 12 from being destroyed by the pressing force described later. This is because it provides a well-balanced combination of buffering force (elasticity). Furthermore, the thickness of the mica sheet 12 is 0.2 m.
Of course, m varies to some extent depending on the electrical insulation required.

The pair of covering materials 9 and 10 on the front and back are respectively
A protruding strip 14 for preventing deformation, as shown in No. 197052, is provided over the entire periphery, and with the protruding strip 14 as a boundary, the inner side is a flat portion 15 and the outer side is a flange-shaped portion 16. The pair of coating materials 9.10 are provided in spots on each flat portion 15 of each coating material 9.10 in such a manner that the tips 17 are in contact with the opposing tips 17 disposed opposite each other. The plurality of invaginations 18,...
--1-- by spot welding, and then the overlapping flange-shaped parts 16 and 16 are also connected by spot welding to achieve a sealed state, and at this time, a constant clamping force is applied. is applied to the laminate 8. It goes without saying that the recessed portion 18 can be provided in such a manner that its tip 17 contacts the flat portion 15 on the other side.

In this way, the heat dissipation plate 7 is made of mica sheet 12 and 0.2 to 0.4 mm thick, which is the minimum thickness necessary for electrical insulation.
am thick carbon sheet 13 to give this heat sink 7 flexibility that can follow the deformation of the covering material 9.10,
Always PTC heating element 4 and covering material 9 as the final heat dissipation surface
．． 10 can be thermally conductively connected with sufficient thermal conductivity and area, and the deformation that occurs in the covering materials 9 and 10 during sealing can be minimized by spot welding through the interposition of the invaginated portion 18. Combined with the fact that
This means that the necessary thermal conductivity can be ensured.

Furthermore, the elasticity of the carbon sheet 13 acts as a buffering force, which prevents the mica sheet 12 from being destroyed by the clamping force of the covering material 9.10, thereby ensuring electrical insulation. In addition, by adopting spot welding through the recessed part 18, one reason is that the heat applied during processing is minimized and thermal deformation is reduced. The invaginated portion acts like a reinforcing rib and provides resistance against thermal deformation, thereby minimizing deformation of the covering material 9 and 10 during processing. This means that waterproofness can be ensured.

<Effects of the Invention> As explained above, the present invention connects the covering materials by spot welding through a plurality of indentations provided in spots, and connects the covering materials by spot welding, and also connects the covering materials by spot-welding the flange-like portions on the periphery that overlap each other. Also, since the connection is made by spot welding for sealing, one reason is that the heat applied during processing is minimized, reducing thermal deformation. These invaginations act like reinforcing ribs and provide resistance against thermal deformation, resulting in less deformation during processing of the covering material, resulting in better thermal efficiency (thermal conductivity), and moreover, in liquid heating. It is possible to provide a heating element that has more reliable waterproof properties when used for commercial purposes.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view schematically showing a heating element, and FIG. 2 is a schematic sectional view of the heating element. 1---------・Heating element 4--------- PTC heating element 7...
- Heat dissipation plate 8 --- Laminate 9, lO --- Covering material

Claims (1)

[Claims] Electrodes and heat sinks for electrical insulation are laminated symmetrically on both sides of a plurality of positive temperature coefficient heating elements arranged in a flat plate shape,
In a heating element formed by covering and sealing this laminate with a pair of covering materials, the pair of covering materials are connected by spot welding through a plurality of indentations provided in spots in each. 1. A heating element characterized in that the flange-like portions of the circumferential edges that overlap each other are also connected by spot welding to be sealed.