JPS5843189Y2 - Three-dimensional mesh heating element - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a three-dimensional mesh heating element.

Conventionally, ceramic heating elements for the purpose of heat exchange are Ba.
TiO3-based semiconductor porcelain is used, but each piece can generate only a few watts of heat, and in order to increase the heat output, it requires installation on a large heat sink or multiple pieces of positive characteristic porcelain. Therefore, the heating element became large and uneconomical.

Also, attempts were made to increase the calorific value by increasing the surface area by making it cylindrical, but this resulted in an extremely large volume and was impractical.

Therefore, a heat generating device was developed in which the heat generating element was composed of a positive temperature coefficient thermistor porcelain 2 having a large number of through holes 1 like a one-hole honeycomb structure in FIG. It is known from, for example, Japanese Patent No. 51-48815, and has been put into practical use.

In addition, the harmonica type shown in Figure 2 has also been put into practical use, but all of them have drawbacks such as the high cost of molds, manufacturing equipment, and assembly work associated with molding the porcelain.To solve this problem, polyurethane, A barium titanate-based semiconductor composite exhibiting positive resistance-temperature characteristics is calcined to create a net-like molded body made of polyester, polyether, Japanese paper, etc. as a base and having a three-dimensional skeletal structure and similar in shape to that shown in Fig. 3. The slurry is applied to the skeleton of a three-dimensionally structured reticular molded body by pulverizing it into a fine powder, immersing it in a slurry mixed with water or a binder, and drying it at a temperature of 1300°C. After firing for a time, a ceramic body with a hard network crosslink in a random shape and a three-dimensional space as shown in Fig. 4, which is similar to the molded body, was obtained, but because of the random crosslink structure, it is extremely weak against external stress. , part of the tissue is easily destroyed, and there are disadvantages in holding the heating element.

Furthermore, the surface of the heating element has large irregularities, and there is no flat part as seen in ordinary disc-shaped ceramic elements, which causes problems in contacting the electrodes with the external lead terminals.

The present invention relates to a three-dimensional mesh heating element that eliminates the above-mentioned drawbacks, and is used to draw out the electrodes of the three-dimensional mesh heating element with positive resistance-temperature characteristics, and to maintain the structure and protect it from external stress. This purpose is achieved by a metal plate with ventilation windows that pass through the mesh.The metal plate forms a structure by adhering to an insulator, and the surface of the three-dimensional mesh heating element is randomly cross-linked, so it has the same internal structure. If you just touch the metal plate to this surface, it will not work.
The heating element and the metal plate only make point contact, and the electrodes of the heating element may be burned out by the applied current.

To avoid this, a tongue piece is provided on a part of the metal plate and a conductive paste is adhered to it.

The conductive paste can penetrate into a part of the structure of the three-dimensional network structure and be brought into close contact with the structure.

For this reason, the electrical contact surface has a large area, and the electrodes are not destroyed by the applied current.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in FIGS. 5 and 6. FIG. 5 is a perspective view of a heating element structure with a three-dimensional network skeleton, and FIG. 6 is a perspective view of a heating element structure with a three-dimensional network skeleton structure. This is a partial enlarged cross-sectional view showing electrodes provided on two opposing sides of PTC thermistor porcelain and tongues of a metal plate bonded to the electrodes with conductive paste. The polyurethane foam is immersed in a slurry of a barium titanate-based semiconductor ceramic composition to adhere to it, dried, and then sintered at 1200 to 1400°C.

Note that the shape of this positive temperature coefficient thermistor porcelain can be made by cutting polyolethane foam into any desired size.

The opposite 2 of the positive temperature coefficient thermistor obtained in this way
Silver electrode paste is applied to the surface and baked to form an electrode to obtain a heating element, and the heating element is protected from external stress to facilitate the extraction of the electrode. 11 is made of copper, brass, etc. Air-tight metal plate formed from metal, 12
is an insulating plate made of high-temperature resin, ceramic, etc. that insulates the two metal plates 11 and fixes the metal plates 11,
The heating element 15 is fixed to the tongue piece 13 provided in the window of the metal plate 11 via a conductive paste 14, and the metal plate 11 is fixed to the insulator 12 using conductive or non-conductive paste to form a heat generating element. It is a three-dimensional mesh heating element in which the element 15, the metal plate 11, and the insulator 12 are integrated.

In addition, the polyurethane foam in the above example was 38
It was cut into a size of 24 x 10 mm, immersed in a slurry of a positive temperature coefficient thermistor porcelain composition with a cue point of 220°C, and dried 6 times, then sintered at 1280°C to obtain a positive temperature coefficient thermistor porcelain. When a voltage of 1QQ VAC was applied between the electrodes of a heating element obtained by providing silver electrodes on two opposing wide surfaces in ventilation at a wind speed of 9 m/s, an output of 100 W was obtained.

The embodiment shown in FIG. 5 shows a heating element divided into two parts, which is caused by the difference in thermal expansion coefficient between the heating element and the metal plate depending on the size of the heating element. This is to prevent breakage, and depending on the shape and dimensions, it may not be necessary to divide it into two.

Further, in the embodiment, the tongue piece and the heating element are fixed with a conductive paste, but a conductive material such as solder may be used.

As described above, the present invention has many effects, such as simultaneously making electrical contact and fixing between the electrodes of the heating element and the metal plate, and protecting the heating element from external stress with the metal plate. This allows for simplification in manufacturing.

[Brief explanation of the drawing]

Figure 1 shows a conventional honeycomb structure heating element, A is a perspective view,
The opening is a partially enlarged perspective view of A, Fig. 2 is a perspective view of a heating element with a harmonica structure, Fig. 3 is a front view of the polyurethane foam, Fig. 4 is a partially enlarged view of the three-dimensional mesh heating element, and Fig. 5 is a partially enlarged view of the three-dimensional mesh heating element. FIG. 6 is a perspective view of the three-dimensional mesh heating element of the present invention, and FIG. 6 is a partially enlarged sectional view of the tongue piece provided in the ventilation window of the metal plate of the present invention and the heating element element bonded together with conductive paste. 11: metal plate with ventilation window, 12: insulator, 13: tongue piece, 14: conductive paste 1-115: heating element.

Claims (1)

[Scope of utility model registration request] A heating element is provided with a terminal formed by providing opposing electrodes to PTC thermistor porcelain having a three-dimensional network structure and bringing a metal plate into contact with the electrodes, in which a mesh of PTC thermistor porcelain is attached to the metal plate-like terminal. Forms a ventilation window that can be passed through,
A three-dimensional mesh heating element characterized in that at least one tongue piece is formed in the window, and the metal plate and the electrode of the positive temperature coefficient thermistor porcelain are connected and fixed with a conductive paste or a conductor.