JPS585501Y2 - Constant temperature heating element for electric mosquito repellent - Google Patents

Description

[Detailed description of the invention] The present invention uses a positive temperature coefficient thermistor as a heat source for an electric mosquito repellent heating element to reduce the difference in temperature distribution on the surface of the heat sink that heats the insecticidal mat. The present invention aims to provide a constant temperature heating element for an electric mosquito repellent that is inexpensive and has a structure that is suitable for mass production.

Conventionally, when a positive temperature coefficient thermistor is used as a heating element, it has been used as a heating element for electric mosquito repellents because the temperature of the heating element hardly changes due to voltage fluctuations, the temperature rises quickly, and there are few sudden risks such as overheating. It has been put into practical use.

However, the heating temperature distribution on the surface of the mosquito repellent's insecticidal mat has a large difference, with the heating temperature being high at the center and low at the periphery.

When a disk-shaped positive temperature coefficient thermistor is used for mass production, and the element size button and other parts are made smaller in order to manufacture it at a lower cost, the above-mentioned drawbacks inevitably become noticeable and the situation is not satisfactory. .

The present invention has been devised to eliminate the above-mentioned drawbacks of the conventional art, and one embodiment thereof will be described below with reference to the drawings.

1. In the figure, 1 is a box-shaped case made of a heat-resistant insulator and open only at the top, and through-holes 1a and 1b are formed at both ends of the bottom.

Reference numeral 2 designates an upwardly curved rectangular spring terminal which is placed on the bottom surface inside the case 1 by inserting a downwardly protruding terminal portion 2a provided at one end into the through hole 1a; One terminal of the terminal portion 2a is formed outside the case 1.

Reference numeral 3 denotes a disk-shaped positive temperature coefficient thermistor placed on the spring terminal 2 and housed in the case 1, and electrodes 3a are provided on both surfaces thereof.

Reference numeral 4 designates a rectangular fixed terminal which is placed on the PTC thermistor 3 and is inserted and fixed inside the upper surface opening of the case 1 by means of a tongue piece 4a which is integrally provided at the end thereof. A terminal portion 4b protruding downward is inserted into the through hole 1b of the case 1, and the terminal portion 4b forms the other terminal outside the case 1.

5 is a rectangular insulating sheet placed on the fixed terminal 4 on the upper opening side of the case 1; 6 is the insulating sheet 5;
It is a rectangular heat-uniforming plate with a hole 6a formed in the center to be placed on top, and the heat-uniforming plate 6 is made of a material with better thermal conductivity than the insulating sheet 5 and the heat sink described later. Ru.

Reference numeral 7 denotes a rectangular heat dissipation plate placed on the heat equalizing plate 6. This heat dissipation plate 7 is made of heat-resistant and chemical-resistant stainless steel or the like because the insecticidal mat (not shown) is heated on it. It is made of a material, and fixed arms 7a are integrally provided at both ends thereof.

8 places the case 1 on the bottom flat part and attaches the heat dissipation plate 7.
It is a U-shaped band having a mounting arm 8a' for fixing the entire body, and a mounting hole 8b is formed in the mounting arm 8a.

Then, inside the case 1, there is a spring terminal 2 and a positive temperature coefficient thermistor 3.
Then, the fixed terminal 4 is housed and the case 1 is placed on the band 8, and then the insulating sheet 5, the heat equalizing plate 6, and the heat sink plate 7 are placed on the fixed terminal 4.

Thereafter, the fixing arm 7ak of the heat sink 7 is inserted into the attachment hole 8b of the band 8 and bent, thereby fixing the entire body, thereby completing a constant temperature heating element for a mosquito repellent.

Here, the effect of the heat equalizing plate 6, which is the gist of the present invention, will be explained using specific examples.

In addition, in the above embodiment, there is a hole※※6 in the center of the heat soaking plate 6.
Although the explanation has been given regarding the hole 6a formed in the hole 6a, the present invention is not particularly limited by the presence or absence of the hole 6a, as is clear from the experimental results described later.

1. The band 8 is a steel plate with a thickness of 0°5TnrrL, the case 1 is made of mullite, the spring terminal 2 is a stainless steel plate with a thickness of about 0°3, and the positive temperature coefficient thermistor 3 is made of aluminum sprayed on almost the entire surface of both opposing surfaces. electrode 3
a, 0.3mm thick stainless steel plate as fixed terminal 4, 37m7+1X 25 as insulating sheet 5
mm, thickness 0.35m1nO, 37 as the soaking plate 6
Aluminum plate with m1 x 25 mm and thickness of 0.5 mm, 37 mm x 2 as heat sink 7! A stainless steel plate made of Mi and having a thickness of 0.41 nm was used.

Experiments were then carried out by varying the element dimensions of the positive temperature coefficient thermistor 3, the dimensions of the fixed terminal 4, and the dimensions of the heat equalizing plate 6 (including the case where there is no hole 6a).

The results are shown in the table below.

As is clear from the above table, the difference in temperature distribution between the central part and the edge (periphery) of the heat sink plate 7 is 35% in the case without the heat equalizing plate 6.
.degree. C., and even if the element diameter of the positive temperature coefficient thermistor 3 and the dimensions of the fixed terminal 4 are increased, the difference in temperature distribution is only slightly improved to 30.degree.

On the other hand, the one with the soaking plate 6 has a hole 6ak in the center.
The difference in temperature distribution is small, 6 to 7°C with holes 6ak formed and the diameters varied, and the difference in temperature distribution is small.
Although no particular effect was observed, the difference in temperature distribution was reduced to 6 to 7°C by adding the soaking plate 6, indicating that the effect of providing the soaking plate 6 was significant. .

The constant temperature heating element for an electric mosquito repellent according to the present invention is constructed as described above, and by providing a heat equalizing plate such as an inexpensive aluminum plate, the difference in temperature distribution on the heat sink is significantly reduced. It is.

In addition, the increase in material and training costs is small, and the number of man-hours for assembly in mass production is hardly increased.

[Brief explanation of drawings]

The figure is an exploded perspective view showing an embodiment of a constant temperature heating element for an electric mosquito repellent according to the present invention. DESCRIPTION OF SYMBOLS 1...Case, 2...Spring terminal, 3...Positive characteristic thermistor, 3a...Electrode, 4...Fixed terminal, 5...
- Insulating sheet, 6... heat soaking plate, 7... heat sink.

Claims (1)

[Scope of utility model registration request] A spring terminal, a positive temperature coefficient thermistor button with electrodes on both surfaces, and a fixed terminal are assembled in order into a case made of a heat-resistant insulator, and an insulating sheet, a heat equalizing plate button, and an insecticidal pine (pine) k heating are placed on the fixed terminal. A fixed-temperature heat generator for an electric mosquito repellent, comprising heat sinks stacked one on top of the other and fixed as a whole by appropriate means, and the heat sink plate made of the insulating sheet and a material with excellent thermal conductivity like the heat sink. body.