JPS6230791Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heat generating device made of semiconductor porcelain having positive resistance-temperature characteristics.
The present invention relates to a heat generating device formed by providing a large number of through holes in semiconductor porcelain having positive resistance-temperature characteristics.

In recent years, as an alternative to conventional heating devices using nichrome wire, etc., devices with positive resistance-temperature characteristics have been introduced because they have a self-temperature control function, generate a large amount of heat per unit volume, and are structurally sound. A heat generating device has been used in which a semiconductor ceramic having a large number of through holes is provided as a heat generating body and air is blown to the heat generating body. An example of a heating device of this type is shown schematically in FIG. 1 of the accompanying drawings. FIG. 1 schematically shows a longitudinal section of a heat generating device, which can be used for example in a hair dryer, and has a heating element 2 supported by a support member 3 in a cylindrical housing 1. The air blower 5 further includes blower blades 5 driven by a motor 4. This heating element 2 is made of semiconductor porcelain having positive resistance temperature characteristics.
It is formed into a disk shape from a so-called PTC material, and as shown in the front view of Figure 2,
A large number of through holes 6 having a square cross section are formed and arranged at equal intervals. As clearly shown in FIG. 1, electrodes 7 and 8 for power supply are provided on both end faces of this heating element 2, and when these electrodes 7 and 8 are connected to a power source, the through hole 6 A current flows through the partition wall 9 between them, causing the heating element 2 to generate heat. When power is supplied to the heating element 2 and the motor 4 is energized to drive the blower blades 5, the ventilation hole 11 of the rear end plate 10 of the housing 1, the through hole 6 of the heating element 2, and the front surface of the housing 1 are activated. Air is blown through the output opening 12 of the heating element 2, and the airflow is heated when passing through the through hole 6 of the heating element 2.
Warm air can be obtained from 2.

This type of heating device is advantageous in that it is structurally more solid, has a self-temperature control function, and generates a large amount of heat per unit volume compared to conventional devices using nichrome wire, etc. The conventional structure has the following drawbacks, and there is still room for improvement. That is, FIG. 3 is an enlarged view of part A in FIG. 2, and as clearly shown in FIG. 3, the thickness t of the interval between the through holes 6 of the conventional heating element 2 is: It was considered to be almost uniform everywhere. This is because this type of heating element is manufactured by extrusion molding, etc., and in order to make it easy to manufacture, it is preferable to make the shapes of the through holes and partition walls as simple as possible. This is thought to be due to the fact that it was thought that it would be better to do so in order to obtain a uniform temperature distribution in order to prevent damage due to thermal distortion. However, in the case where the thickness of the interval between the through holes is made uniform everywhere, the third
In the figure, portion 14 has a larger specific surface area than portion 13, and heat dissipates more quickly. In other words, by making the thickness of the partition wall 9 uniform everywhere, heat is more likely to be trapped in the portion 13, and the heating element with this conventional structure has a uniform temperature throughout the heating element. It has been found that there is a problem from the point of view of obtaining the maximum amount of heat generated per unit volume by obtaining distribution, making the amount of heat generated uniform as a whole, and utilizing the entire heating element without wasting it.

In view of such prior art, the purpose of the present invention is to provide a heat generating device that makes full effective use of the semiconductor ceramic material forming the heat generating element and can obtain a higher calorific value per unit volume. It is.

The above-mentioned object of the present invention is to provide a heat generating device including a heating element formed by providing a large number of through holes in a semiconductor porcelain having positive resistance-temperature characteristics and forming electrodes on both surfaces thereof, in which the thickness of a partition wall surrounding the through holes is reduced. This is achieved by making the specific surface areas of each part of the heating element different so that they are approximately equal.

Further, according to the embodiment of the present invention, the thickness of the partition wall increases from the vicinity of the junction with the adjacent partition wall as the distance increases.

Next, the present invention will be described in more detail with reference to FIGS. 4 and 5 of the accompanying drawings.

FIG. 4 is a diagram similar to FIG. 3 showing a heating element used in a heating device as an embodiment of the present invention. The heating element shown in Figure 4 is made into a disk shape from a so-called PTC material, which is a semiconductor porcelain that has a positive resistance temperature characteristic and is made by adding a small amount of additives to make it a semiconductor to _barium titanate (BaTiO 3 ) and sintering it. It is similar to the conventional heating element described with reference to FIGS. 1 to 3 in that a large number of through holes 6A having a generally square cross section are formed and arranged at equal intervals. However, according to the present invention, the partition wall between the through holes 6A of the heating element in FIG.
The thickness of the partition wall 9A surrounding A is not uniform in the cross-sectional direction, and increases as the distance from the joint 15 with the adjacent partition wall increases. Partition wall 9A
The thickness t ₁ at the base is the minimum, the thickness t ₂ at the middle part is the maximum, and the thickness changes linearly between them. For this reason, the cross-sectional shape of the through hole 6A is no longer a perfect square, but by having a partition wall structure with different thicknesses, the specific surface area of each part of the heating element relative to the volume of the semiconductor ceramic is approximately equal. Since they are equal, heat will not accumulate in the joint 15. Therefore, according to the heating element having the structure shown in FIG. 4, the temperature of each part of the heating element during use can be made almost uniform, and the amount of heat generated can also be made almost uniform, and as a result, the semiconductor ceramic material can be made more perfect. Effective utilization can be achieved, and the amount of heat generated per unit volume can be increased. Furthermore, damage due to thermal strain is less likely to occur.

In the embodiment shown in FIG. 4, the thickness of the partition wall 9A is
Although we designed it to change linearly from the minimum t ₁ to the maximum t ₂ , it is not limited to this, and as long as the specific surface area of each part is approximately equal, it can be changed using an arbitrary curve. Similar effects can be obtained.

FIG. 5 is a diagram similar to FIG. 4 showing a heating element used in a heating device as another embodiment of the present invention. The heating element shown in FIG. 5 has the following features:
It is similar to the embodiment shown in the figure. In this embodiment as well, the thickness of the partition wall 9B between the through holes 6B is not uniform in the cross-sectional direction, and increases as the distance from the joint 15A with the adjacent partition wall increases. That is, the thickness t ₁ at the base of the partition wall 9B is the minimum, the thickness t ₂ at the middle portion is the maximum, and the thickness changes in a curved manner between them. For this reason, the cross-sectional shape of the through hole 6B is no longer a perfect regular hexagon, but by creating a partition wall structure with different thicknesses, the specific surface area of each part of the heating element relative to the volume of the semiconductor ceramic can be reduced. Since they are equal, the joint part 15A
This eliminates the possibility of overheating. Therefore, according to the heating element having the structure shown in FIG. 5, it is possible to create a heating device which, like the embodiment shown in FIG. 4, has a higher calorific value per unit volume and has no problems such as damage due to thermal distortion. can be provided.

In the above-mentioned embodiments, the cross-sectional shape of the through-hole was generally a square or a regular hexagon, but the shape of the through-hole is not limited to this, and may be any other polygonal shape such as a triangle or an octagon. But it's good. Further, the electrodes provided on the heating element may be ohmic or non-ohmic, and the same effects of the present invention can be obtained. Furthermore, the fluid passed through the through hole of the heating element is not limited to air, but may be any other fluid such as liquid.

[Brief explanation of the drawing]

FIG. 1 of the accompanying drawings is a schematic longitudinal sectional view showing an example of a conventional heat generating device, FIG. 2 is a front view of a heating element in the heat generating device of FIG. 1, and FIG. 3 is an enlarged view of part A in FIG. 2. 4 and 5 are views similar to FIG. 3, respectively showing heating elements as two different embodiments of the present invention. 2... Heating element, 6A, 6B... Through hole, 7, 8
... Electrode, 9A, 9B ... Partition wall, 15, 15A...
...junction.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A heating device comprising a heating element formed by providing a large number of through holes in semiconductor porcelain having positive resistance-temperature characteristics and forming electrodes on both sides of the heating element,
A heat generating device characterized in that the thickness of the partition wall surrounding the through hole is varied so that the specific surface area of each part of the heat generating body is approximately equal. (2) The heat generating device according to claim 1, wherein the thickness of the partition wall increases as the distance increases from the vicinity of the joint with the adjacent partition wall.