JPH0714666A - Sheet heating element - Google Patents

Abstract

(57) [Abstract] [Purpose] In the heating element used in various electrical equipment,
It is an object of the present invention to provide a sheet heating element with improved workability, assembling property, durability, reliability, safety and performance. [Configuration] A foil-shaped heating element on the same plane having a top surface covered with a first insulating material 5 and a bottom surface covered with a second insulating material 6 on the back side of the bottom surface of the container 2 having the heat transfer plate 1 on the bottom surface. The second insulating material 6 has a heat-generating part 4 having a heat-dissipating part 7, a heat-diffusing plate 11 having a good heat conductivity such as an aluminum plate disposed on the lower surface of the heat-generating part 4, and a back plate 13. Through hole 6a for exposed portion of heating element
And a through hole 6 for the exposed portion of the foil-shaped heating element is provided in the heat diffusion plate 11.
A through hole 12 larger than a is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet heating element mounted on an electric water heater or the like.

[0002]

2. Description of the Related Art Conventionally, a heating element of this type has a structure as shown in FIGS.

[0003] A structure of a conventional heating element will be described below with reference to FIG.
-It demonstrates, referring FIG. As shown in the figure, a heating wire 103 is wound around a substrate 104 on the back surface of a heat transfer plate 102 formed by projecting the central portion of the bottom surface of the inner container 101 of the electric water heater upward, and the upper and lower portions of the heating wire 103 are insulated. A winding type heating element 107 covered with 105 and 106 is arranged via a heat conduction plate 108. This winding-type heating element 107 has a through hole in the central portion and a heat diffusion plate 110 having good thermal conductivity having an outer peripheral edge portion 109 and a backing material 111, and is press-fitted to the lower surface of the heat transfer plate 102 on the bottom surface of the container. Has been done. In addition, the terminal portion 112 of the heating wire 103 is connected to the terminal plate 114 that is connected to the power supply portion by overlapping the additional wire 113.

[0004]

However, in such a conventional structure, the heating wire 103 has to be wound around the substrate 104, which requires a considerable amount of time and effort for the winding work and the heat generated during the winding work. There is a problem that a short circuit occurs due to slack of the wire 103. In addition, there is a fear that a force is applied during the winding work or the assembling work to damage the protrusion of the groove portion of the substrate, which is the heating wire winding portion. further,
The terminal line 112 of the heating wire 103 must be overlapped with the additional line 113 to suppress the heat generation in this part and be connected to the terminal plate 114 connected to the power supply unit, which causes a problem of poor workability such as wire processing. It was The present invention solves the above problems, and an object of the present invention is to provide a sheet heating element with improved processability, assemblability, durability, reliability, safety and performance.

[0005]

In order to achieve the above object, the present invention according to claim 1 is such that a container having a heat transfer plate on the bottom surface is on the back side of the bottom surface and the top surface is a first insulating material. A heating element portion having a foil-shaped heating element on the same plane which is covered and whose lower surface is covered with a second insulating material, and a heat diffusion plate having good heat conductivity such as an aluminum plate disposed on the lower surface of the heating element portion. And a back plate, the second insulating material is provided with a through hole for the foil-shaped heating element exposed portion, and the heat diffusion plate is provided with a through hole larger than the through hole for the heating element exposed portion. Is provided with a convex portion which is larger than the through hole of the heat diffusion plate and has substantially the same shape as the through hole of the heat diffusion plate.

According to a second aspect of the present invention, in addition to the first aspect of the invention, the heat diffusion plate disposed on the lower surface of the heating element has a concave shape with a width wider than the line width of the foil heating element. The step is provided in substantially the same shape as the heating element pattern.

[0007]

According to the invention described in claim 1, the foil-shaped heating element is made of a metal foil formed by etching, pressing, etc., and there is no conventional work of winding the heating wire around the mica itself, and one sheet is used. It is possible to process the foil-shaped heating element from the plate material of and reduce the number of parts. Further, since the heating element part is treated as one unit, workability and assemblability can be improved.
In addition, the distance between the lines is kept constant, and it is possible to prevent disconnection due to contact between the line and another line, thereby improving durability. In addition, even if the temperature controller that controls the heating element fails and continuous air-cooling energization occurs, the heat diffusion plate melts and flows into the through hole for the exposed portion of the foil heating element, which short-circuits the foil heating element. Safety can be improved by breaking the wire and stopping energization.

According to the second aspect of the present invention, a concave step having a width wider than the line width of the foil-shaped heating element is formed in the heat diffusion plate disposed on the lower surface of the foil-shaped heating element in substantially the same shape as the heating element pattern. Since it is provided, it is possible to improve the adhesion with the foil-shaped heating element, improve the heat conduction to water in the container, and suppress the temperature rise of the heater wire to a low level. In addition, the movement of the heater wire due to expansion / contraction of the wire can be reduced to improve safety.

[0009]

EXAMPLE 1 Example 1 of the present invention will be described with reference to FIGS. In the figure, reference numeral 1 denotes a heat transfer plate, which forms a peripheral side edge 1a by projecting a central portion upward, and an outer edge portion of the peripheral side edge 1a is liquid-tightly welded to a lower end of a cylindrical body by means such as welding. By being fixed, the metal container 2 for storing the liquid is formed.

A heating element portion 4 is mounted on the lower surface of the heat transfer plate 1 through a heat conductive plate 3 made of a flat plate having good heat conductivity such as an aluminum plate or a surface-treated steel plate. As shown in FIG. 1, the heating element portion 4 is a foil-shaped heating element made of a foil-shaped resistor formed by pressing or the like between respective layers of a first insulating material 5 and a second insulating material 6 made of mica or the like. 7
It is formed by. The second insulating material 6 is provided with a through hole 6a for the exposed portion of the foil-shaped heating element to expose a part 7a of the foil-shaped heating element 7. In addition, the terminal portion 8 of the foil-shaped heating element is the second
The third insulating material 10 is bent below the insulating material 6 by about 90 °, and is then covered with the third insulating material 10 on the same plane near the bent portion 9 below the second insulating material 6.

The heat transfer plate 1 is provided on the lower surface of the heating element portion 4.
A heat diffusion plate 11 having good heat conductivity, such as an aluminum plate, which is fitted to the inner wall of the peripheral side edge 1a is disposed, and the heat diffusion plate 11 is larger than the through hole 6a for the exposed portion of the foil-shaped heating element. Hole 12
Further, a back plate 13 having good heat conductivity such as a surface-treated steel plate having a convex portion 13a larger than the through hole 12 and having substantially the same shape as the through hole 12 is provided on the lower surface thereof.
1 is fixed to the bottom surface of the container 2 so as to press the heat transfer plate 1 against the heat transfer plate 1. Further, the heat conduction plate 3, the heating element portion 4, the heat diffusion plate 11 and the back plate 13 have a through hole in the center, and contact the lower surface of the heat transfer plate 1 through the through hole, A sensor 14 for controlling the liquid temperature of the container 2 is provided.
Reference numeral 15 in FIG. 6 is a body that is wrapped with the container 2 via a space.

To explain the operation in the above configuration, the liquid in the container 2 is heated by the heat generated by the foil-shaped heating element 7 when the foil-shaped heating element 7 is energized, and is controlled to a predetermined liquid temperature by the sensor 14. .

As described above, in the first embodiment, the foil-shaped heating element 7 is made of metal foil formed by etching, pressing, etc., and there is no need to wind the heating wire around the mica. The heating element can be processed from one plate material, and the number of parts can be reduced. Further, since the heating element portion 4 is treated as one unit, workability and assemblability can be improved. In addition, the distance between the wires is kept constant, and the wires can be prevented from being broken due to contact with each other, and the durability can be improved. In addition, even if the temperature controller for controlling the heating element fails and the continuous air-cooling energization occurs, the thermal diffusion plate 11 melts,
The safety can be improved by flowing into the through hole 6a for the exposed portion of the foil-shaped heating element and short-circuiting or breaking the foil-shaped heating element 7 to stop the energization.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. Foil heating element 7
Since the concave-shaped step 11a having a width wider than the line width of the foil-shaped heating element 7 is provided on the heat diffusion plate 11 disposed on the lower surface of the same in the shape of the heating element pattern, the adhesion with the foil-shaped heating element is improved. It improves the heat conduction to the water in the container, suppresses the temperature rise of the heater wire, and improves the reliability and durability. In addition, the movement of the heater wire due to expansion and contraction can be reduced, and safety can be improved.

[0015]

As is apparent from the above description, according to the present invention, the foil-shaped heating element is made of metal foil formed by etching, pressing or the like, and the conventional heating wire is wound around mica. Without the work itself, the heating element can be processed from one plate material and the number of parts can be reduced. Further, since the heating element part is treated as one unit, workability and assemblability can be improved. In addition, the distance between the lines is kept constant, and it is possible to prevent disconnection due to contact between the lines and improve the durability. In addition, even if the temperature controller that controls the heating element fails and continuous air-cooling energization occurs, the heat diffusion plate melts and flows into the through hole for the exposed portion of the foil heating element, which short-circuits the foil heating element. Safety can be improved by breaking the wire and stopping energization.

Further, since a concave step having a width wider than the line width of the foil-shaped heating element is provided on the heat diffusion plate disposed on the lower surface of the foil-shaped heating element in substantially the same shape as the heating element pattern, the foil-shaped heating element is formed. It is possible to improve the adhesion with and improve the heat conduction to the water in the container, suppress the temperature rise of the heater wire, and improve the reliability and durability. In addition, the movement of the heater wire due to expansion and contraction can be reduced, and safety can be improved.

[Brief description of drawings]

1A is an exploded perspective view of a planar heating element according to a first embodiment of the present invention, FIG. 1B is an exploded perspective view of a heating element portion according to the first embodiment, and FIG. 1C is a foil shape according to the first embodiment. Perspective view showing the pattern of the heating element

FIG. 2 is a sectional view of a main part of a foil-shaped heating element according to the first embodiment of the present invention.

FIG. 3 is a plan view of the exposed portion of the foil heating element.

FIG. 4 is an exploded perspective view of a sheet heating element according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a foil-shaped heating element according to the second embodiment.

FIG. 6 is a partial cross-sectional view of an electric water heater incorporating a planar heating element according to an embodiment of the present invention.

FIG. 7 is an exploded perspective view of a conventional heating element.

FIG. 8 is a plan view of the heating element.

FIG. 9 is a cross-sectional view of essential parts showing an assembled state of the heating element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat transfer plate 2 Container 4 Heating element part 5 1st insulating material 6 2nd insulating material 6a Through hole for exposed portions of foil heating element 7 Foil heating element 11 Heat diffusion plate 11a Concave step 12 Through hole 13 Back Face plate 13a convex part

Claims (2)

[Claims] 1. A coplanar foil-like heating element having an upper surface covered with a first insulating material and a lower surface covered with a second insulating material, on the back side of the bottom surface of a container having a heat transfer plate on the bottom surface. It has a heating element part, a heat diffusion plate having good thermal conductivity such as an aluminum plate disposed on the lower surface of the heating element part, and a back plate, and the second insulating material is used for the foil-shaped heating element exposed part. A hole is provided, a through hole that is larger than the through hole for the heating element exposed portion is provided in the heat diffusion plate, and a back plate is larger than the through hole of the heat diffusion plate and has substantially the same shape as the through hole of the heat diffusion plate. A planar heating element, characterized in that it is provided with convex portions. 2. The surface according to claim 1, wherein a concave step having a width wider than the line width of the foil-shaped heating element is provided on the heat diffusion plate disposed on the lower surface of the heating element in substantially the same shape as the heating element pattern. Heating element.