JPS5850634Y2 - heating element device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heating element device using a PTC thermistor (positive temperature coefficient thermistor).The present invention is a heating element device using a PTC thermistor (positive temperature coefficient thermistor). In order to provide an inexpensive heating element device that uses fewer elements, we increased the surface area of the positive temperature coefficient thermistor while reducing pressure loss to the fluid, improving heat dissipation and increasing the amount of heat generated per element. To provide an inexpensive heating element device using fewer sheets.

Furthermore, the present invention provides a highly reliable heating element device even if aluminum, which is inexpensive, is used as the electrode material.

A positive temperature coefficient thermistor has a strong self-temperature control effect, is a stable heating element that does not easily overheat, and is useful as a heat generating device, but the conventional device that combines a large number of positive temperature coefficient thermistors is one with the structure shown in Figure 1. It is being

In FIG. 1, reference numeral 1 denotes a thin plate-like positive temperature coefficient thermistor, and electrodes 2 and 3 made of aluminum sprayed Ni plating, silver paste baking, etc. are provided on both end faces of the positive temperature coefficient thermistor 1.

4 is a cylindrical insulating frame, inside which a large number of thin plate-like positive temperature coefficient thermistors are arranged at regular intervals, and epoxy adhesive (
(not shown).

Reference numerals 5a and 5b are common electrodes made of brass plates, and the portions of this common electrode that come into contact with the thermistor electrodes 2 and 3 are connected with a conductive adhesive 6.

In addition, the common electrodes 5a and 5b are attached to the insulating frame using epoxy adhesive (
(not shown).

The structure shown in FIG. 1 uses a thermistor having electrodes formed on its end face in consideration of ease of assembly and removal of the common electrode.

However, when using a conventional PTC thermistor with the structure shown in Figure 2, electrodes 2 and 3 are formed on each end face and the distance between the electrodes is large, so uniform heat generation does not occur between those electrodes. .

When a part reaches the temperature in the positive characteristic region, that part generates more heat than other parts, so only that part continues to generate heat, and eventually, as shown in curve 8 in Figure 2, ,
The temperature distribution is such that only the vicinity of the center 7 of the thermistor 1 has a high temperature.

Therefore, considering the width of the element, the electrodes 2 and 2 contribute to heat generation.
3, the amount of heat generated per sheet was small, and a large number of positive temperature coefficient thermistors were required as a heating element device.

In consideration of these problems, the present invention proposes a structure that can increase the amount of heat generated by a heat generating device that combines a positive temperature coefficient thermistor and facilitates the formation of electrodes. This will be explained with drawings.

FIG. 3 is an external view of a heating element device according to an embodiment of the present invention, FIG. 4 is a sectional view thereof, and FIG. 5 is a diagram of a heating element used in the embodiment.

Reference numeral 10 is a cylindrical insulating frame body made of heat-resistant phenol resin.

Reference numeral 11 denotes a thin plate-like positive temperature coefficient thermistor, and the two largest planes facing each other are provided with unevenness as shown in the figure.

The direction in which the air passes is in the direction of the arrow in FIG. 5, that is, in FIG. 3, between the thermistors 11 in the frame 10, for example in the vertical direction.

Further, separate electrodes 12,13 are applied to the uneven surface by spraying aluminum.

14a, 14b are the electrodes 12.1 in each of the multiple elements.
This terminal board is made of brass plate or the like to facilitate parallel connection of 13 terminals.

14a and 14b are used for each element, and are electrically connected to the electrodes 12 and 13 by conductive adhesive or the like, and are fixed so as to protrude in opposite directions.

A plurality of such thin plate positive temperature coefficient thermistors are installed in the insulating frame 10.
Use epoxy adhesive to secure the parts at regular intervals.

15a, 15b are annealed copper wires and terminal boards 14a, 1
It is soldered to 4b and serves as the common electrode of the positive temperature coefficient thermistor.

16a and 16b are power supply terminal plates made of brass plates or the like, and are welded to mild steel wires 15a and 15b.

Further, the power supply terminal plates 14 a and 14 b are fixed to the insulating frame 10 with epoxy adhesive.

The apparatus shown in FIGS. 3 and 4 has a configuration in which five heating elements each made of thermistor 11 are connected in parallel.

Now, with the conventional electrode having the structure shown in FIG. 2, the temperature distribution of the PTC thermistor was not uniform and the heat generation efficiency was not good.

According to the present invention, first, the electrodes are positioned on the largest plane facing each other.

Therefore, in all the thermistors 11, heat generation occurs at the sixth
It becomes uniform within the maximum plane as shown by curve 20 in the figure,
The amount of heat generated per sheet is large.

Furthermore, in the present invention, the surface area is increased by providing unevenness on the largest plane in a direction that does not impede the flow of air, which improves heat dissipation and further increases the amount of heat generated.

In addition, electrode materials include aluminum spraying, Ni plating,
Baking silver paste has been known for a long time, but in order to apply it to an uneven surface, it is difficult to print silver and electrodes must be applied over a large area, so it is generally difficult to print positive temperature coefficient thermistors for heat generation. The use of expensive silver as an electrode is disadvantageous.

Further, Ni plating requires a complicated process, such as having to remove electrodes on unnecessary surfaces after plating, and is also expensive.

Electrodes made by thermal spraying of aluminum have conventionally had the disadvantage of weak adhesive strength with elements, but by providing irregularities on the element body as in the present invention, adhesive strength and reliability are improved.

Furthermore, aluminum sprayed electrodes are inexpensive even when used over a large area, and can be easily formed, making their use extremely advantageous in terms of mass production.

In this way, the above-mentioned structure of providing unevenness on the largest plane of the heating element and attaching the aluminum sprayed electrode thereto has a double effect on increasing the amount of heat generated, and also provides a reliable and inexpensive electrode. Excellent practical effects can be achieved, such as the simple application of .

In the embodiment of the present invention, an example was shown in which electrodes were provided on the largest plane of the thermistor 11 all over the largest plane of the element, but as shown in FIG. It is also possible that the electrodes 12.13 are not provided.

Furthermore, in the present invention, the method for parallel connection can be modified in various ways.

As described above, according to the present invention, it is possible to increase the amount of heat generated from the heat generating device, and it is also possible to form inexpensive electrodes. It is something that contributes.

[Brief explanation of drawings]

Fig. 1 is an external view of a conventional heating element device, Fig. 2 is a schematic diagram and temperature characteristic diagram of the heating element in the device of Fig. 1,
Figure 3 is an external view of a heating element device according to an embodiment of the present invention;
The figure is a sectional view of the device shown in Figure 3, Figures 5A and B are external views and front views of the heating element used in the present invention, and Figure 6 is a schematic diagram and temperature characteristic diagram of the heating element used in the present invention. , FIG. 7 is an external view of another heating element used in the present invention. 10...Insulating frame, 11...Positive characteristic thermistor, 12°13...Electrode.

Claims (2)

[Scope of utility model registration request] (1) A heating element device in which a plurality of thin plate-shaped positive temperature coefficient thermistors are fixed to an insulating frame at predetermined intervals, and a fluid is passed along the maximum plane of the thin plate-shaped positive temperature coefficient thermistors to heat the fluid, A heating element device, wherein unevenness is provided in a direction substantially perpendicular to a fluid passage direction on the two largest planes facing each other of the thin plate-like positive temperature coefficient thermistor, and electrodes are provided on each of the two largest planes. (2) The heating element device according to claim 1, wherein the electrode is made of an aluminum sprayed electrode.