JPH0244117B2 - HATSUNETSUTAI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heating element for an electric heating appliance for heating liquids such as water, milk, and alcoholic beverages in general households.

2. Description of the Related Art In general, conventional heating elements for electric heating appliances are provided on the market in various embodiments such as space heaters and sheathed heaters. As a conventional space-type mica heater, one disclosed in, for example, Japanese Patent Laid-Open No. 53-32430 is known. This is constructed as shown in Figs. 7 to 10. 1 is an insulating substrate around which a heating wire 2 is wound, through-holes 3 are provided at appropriate places, and an upper insulating plate 4 and a lower insulating plate 1 are provided on both backs. A plate 5 is provided. The upper insulating plate 4 is also provided with a suitable number of through holes 6, and a conductive molten metal plate 7 made of aluminum or the like for shorting is placed so as to cover the through holes 6. Here, the insulating substrate 1
The through holes 3 and 6 of the upper insulating plate 4 are provided at corresponding positions, respectively. An auxiliary insulating plate 8 is provided on the upper surface of the short-circuiting molten metal plate 7, and the whole is covered with a metal holding plate 9,
The metal case 11 is laminated in a crimped state when clamped with 10,
12, it has a liquid-tight configuration. Further, a hole is provided in the center of the metal case 12, and a threaded cylinder 13 is inserted into this hole.
The lead portion 14 of the heating wire 2 is protected by a magnetic tube 15 and led out through the wire. The conventional example shown in FIG. 7 is an example of an electric pot, and 16 is the pot body, 1
7 is a heating element.

Problems to be Solved by the Invention With such a conventional configuration, the degree of lamination adhesion of each component of the heating element is made as good as possible to prevent the wire temperature of the heating wire itself from increasing due to the generation of a space layer,
Design considerations that ensured a certain durability life were essential. For this reason, specific measures include improving the processing accuracy of heating element components, preventing deformation and warping in the initial state, and improving the method of clamping the periphery of the metal case containing insulating plates and metal holding plates. In response to the above items, the power density (W/cm ² ) of the heating element must be set as high as possible within the allowable cost, and a structure to prevent excessive temperature rise has been incorporated. In this case, as the number of parts increases and the structure becomes more complex,
We had to deal with issues such as the need for more measures.

The present invention solves these problems,
The object of the present invention is to provide a heating element with a simple structure for preventing excessive temperature rise and with increased durability.

Means for Solving the Problem In order to solve this problem, the present invention provides a heat generating board, a heat dissipating member with good thermal conductivity installed closely on the bottom surface of the heat generating board, and a heat dissipating member that covers the top surface of the heat generating board. A heat transfer member, and a back member that covers the upper surface of the heat diffusion member, the peripheral edges of the heat transfer member, the heat diffusion member, and the back member are brought into close contact with each other, and each of the heat generation plate, the heat diffusion member, and the back member is A through hole is formed in the center and an annular recess is provided on the upper surface of the back member.

Function: With this configuration, when electricity is applied to the heating element, heat is radiated from the heat transfer member, and heat from the bottom surface is quickly conducted to the periphery through the heat diffusion member, and is radiated upward from the periphery. Since heat is quickly conducted through the heat transfer member, the wire temperature of the heating wire itself is significantly lowered, extending its durable life.
When the heat diffusion member starts to melt during dry firing, the melted heat diffusion member flows into the recessed part of the back member and stays there, causing an artificially large space layer to be formed inside the heating element, causing the temperature of the heating wire to become abnormal. This is to ensure safety by raising the wire and causing it to break.

Embodiment Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 6.

In the figure, 21 is a dish-shaped heat transfer member having side edges 22 on the outer circumferential side, and 23 is a plate-shaped heat transfer member having side edges 22 on the outer circumferential side.
4, with a through hole 25 in the center.
An upward protrusion 26 is formed. A substantially annular recess 23 a is provided on the upper surface of the back member 23 so as to surround the protrusion 26 . 2
Reference numeral 7 denotes a heat generating plate formed by wrapping a heating wire 29 around a ring-shaped insulating substrate 28, and this heat generating plate 27 has ring-shaped insulating plates 30a and 30b stacked on top and bottom to form a heat generating plate body 31. ing. Reference numeral 32 denotes a heat diffusion member having good thermal conductivity and having a through hole 32a in the center and an outer peripheral side portion 32b, which is closely attached to the lower side of the heat generating plate 31. The back member 23 located below the heat-diffusing member 32 is joined to the heat-transfer member 21 covering the upper surface of the heat-generating plate 31 at the side edges 22 and 24 at the center, and the back member 23 is connected to the heat-generating plate 31 and heat-diffusing Part 3
2 is held in a clamped and crimped state. The outer circumferential side 32b of the heat diffusion member 32 is tightly attached to the outer circumferential side of the heat transfer member 21, and is made of aluminum,
It is made of a relatively low melting point metal with good thermal conductivity, such as aluminum alloy. 33 is a lead wire drawn out from the heat generating plate 27.

In the above configuration, the heating wire 2 is connected to the lead wire 33.
By passing an electric current through the heating wire 29, the heating wire 29 is heated, and the heating plate 31 is heated. The heat generated at this time is quickly conducted through the heat transfer member 21 and the heat diffusion member 32, and is radiated from the side edges 22 of the heat transfer member 21. That is, when the heat transfer member 21 is used as a heat radiating surface, the heat from the upper surface of the heat generating plate 31 is radiated from the heat transfer member 21. Furthermore, since the heat from the lower surface of the heating plate 31 is quickly conducted toward the circumferential edge of the heat transfer member 21 via the heat diffusion member 32, the wire temperature of the heating wire 29 itself is significantly lowered and the durability of the heating wire 29 is improved. It extends lifespan. In addition, the insulating substrate 28, insulating plate 30a,
Thermal deformation and warping of 30b and the like are prevented because the heating plate 31 is held between both sides by the back member 23, the heat diffusion member 32, and the heat transfer member 21. Furthermore, if the durability is set to the same level as before, it is possible to set the power density (W/cm ² ) to a high density.
This allows the size of the heating element to be made compact.

When the heating element having the above configuration is applied to an electric heating device and energized for dry firing, the built-in heat diffusion member 32 has a relatively low melting point, so it starts to melt and the back member 23 is heated as shown in FIG. It flows into and stays in the approximately annular recess 23a provided on the upper surface, and at the same time a large space layer is generated between the heat transfer member 21 and the back member 23, and the heating wire 29
The temperature rises even higher, leading to wire breakage.
If the recess 23a is set to an appropriate size, the molten substance of the heat diffusion member 32 will not flow out of the heating element and will not come into contact with the lead wire 33 and the heating wire 29, so that it can be removed after the wire is disconnected. This guarantees electrical insulation.

By the way, the heat transfer member 21 and the back member 23 are made of 18-8 stainless steel plate, 13-18% chrome,
If a ferritic stainless steel plate containing 0.5 to 2% molybdenum is used, joining becomes extremely easy.

Effects of the Invention As described above, according to the present invention, the heating plate is held between the heat transfer member having good heat conduction, the heat diffusion member and the back member, and the peripheral edges of these members are brought into close contact with each other. , the heat generated from the heat generating plate is effectively dissipated from the heat transfer member to the heated object,
In addition, the heat generated from the bottom surface of the heat generating member is radiated from the peripheral edge of the heat transfer member to the heated object through the heat diffusion member and the back member, thereby preventing heat from accumulating inside the heat generating member and reducing the temperature. Can extend power. Furthermore, the simple structure of providing a recess on the upper surface of the back member actively guides the heating wire to disconnection when the temperature rises to ensure safety.

[Brief explanation of the drawing]

Figures 1 to 6 show an embodiment of the present invention, where Figure 1 is a sectional view, Figure 2 is a front view, Figure 3 is a cutaway plan view of the main part of the heating plate, and Figure 4 is a cross-sectional view. 5 is a perspective view of the back member, FIG. 6 is a sectional view showing the state of the heating element when the temperature rises, and FIGS. 7 to 10 are conventional examples. Fig. 7 is a partially cutaway front view of the electric pot, Fig. 8 is a sectional view of the heating element, Fig. 9 is an enlarged sectional view of the main part of the heating element,
FIG. 10 is an exploded perspective view of the heating element components. 21... Heat transfer member, 22... Side edge, 23...
Back member, 23a... recess, 24... side edge, 2
5...Through hole, 26...Protrusion, 27...Heating plate,
28...Insulating substrate, 29...Heating wire, 30a, 3
0b...Insulating plate, 31...Heating plate body, 32...Heat diffusion member, 32a...Through hole, 32b...Outer peripheral side part.

Claims (1)

[Claims] 1 comprising a heat generating plate, a heat diffusion member with good thermal conductivity installed in close contact with the lower surface of the heat generating plate, a heat transfer member covering the upper surface of the heat generating plate, and a back member covering the lower surface of the heat diffusing member, The peripheral edges of the heat transfer member, the heat diffusion member, and the back member are brought into close contact with each other, and the heat generating plate,
A heating element having a through hole formed in the center of each of a heat diffusion member and a back member, and an annular recess provided on the upper surface of the back member.