JPS644310B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a heat-sensitive heating element used in electric carpets and the like.

[Conventional technology]

Conventional heat-sensitive heating elements used in electric heating devices such as electric carpets, as shown in Figure 1,
A linear temperature detection electrode 2 is passed through a tube-shaped thermosensitive resin material 1 made of a polyamide-based material having impedance characteristics, and a strip-shaped heating line 3 that also serves as a temperature detection electrode is spirally arranged on the outer surface of the thermosensitive resin material 1. The outer surface of the thermosensitive resin material 1 was covered with an insulating material 4 to form a cord shape.

The temperature of this thermosensitive heating element was controlled in the following manner using, for example, a temperature control circuit as shown in FIG.

That is, the power supply 8 is connected to the heat-sensitive line 3 of the heat-sensitive heating element through the normally open contact 7a of the power supply relay 7.
is connected, and the oscillation circuit 10 is operated with the output voltage V _D of a power supply circuit 9 that converts the power supply 8 into a constant voltage DC power supply. Then, the high frequency voltage V output from this oscillation circuit 10 is transferred to a voltage dividing capacitor 1.
1 and applied between the temperature detection electrode 2 and the heating line 3 of the heat-sensitive heating element, and outputs a voltage signal corresponding to the impedance in the thickness direction of the thermosensitive resin material 1 of the heat-sensitive heating element through the filter circuit 12. death,
The detected value is input to a comparator circuit 14 that constitutes the preceding stage of the switching circuit 13 at the next stage. This comparison circuit 14 compares the reference voltage with the detected value, and when the detected value falls below this reference voltage, the comparison circuit 14 turns on the switching circuit 13, which had been kept in the on state within the safe temperature range. The transistor 15 constituting the rear stage is turned off, and the excitation coil of the power supply relay 7 connected in series to the transistor 15 stops driving, and the normally open state connected between the power source 8 and the heating line 3 is turned off. The contact 7a is reversed from the previously on state to the off state, thereby cutting off the power supply path to the heater circuit.

[Problem to be solved by the invention]

However, in the structure of the heat-sensitive heating element, the thickness of the heat-sensitive resin material 1 is larger than the temperature detection electrode 2 of the heat-generating line 3.
Because it directly affects the impedance value between
When the heating line 3 generates heat to a high temperature, the impedance of the thermosensitive resin material 1 having a negative temperature-impedance characteristic decreases significantly, resulting in a problem that temperature detection becomes inaccurate.

In order to avoid such a significant drop in the impedance of the heat-sensitive resin material 1 between the heat generating line 3 and the temperature detection electrode 2 at high temperatures, it is necessary to use a material with sufficient thickness as the heat-sensitive resin material 1 in advance. On the other hand, when applying to electric carpets, etc., it is necessary to have appropriate flexibility, so there is a limit to the method of increasing the thickness of the thermosensitive resin material 1 as described above. However, it also has the disadvantage of requiring a large amount of material.

Therefore, an object of the present invention is to provide a heat-sensitive heating element in which the impedance of the heat-sensitive resin material interposed between the heating line and the temperature detection electrode can be set to be sufficiently large without increasing the thickness. It is.

[Means to solve the problem]

The heat-sensitive heating element of the present invention has a strip-shaped heating line that also serves as a temperature detection electrode and a strip-shaped temperature detection electrode that are separated from each other and arranged on the outer surface of a tube-shaped thermosensitive resin material whose impedance changes according to temperature changes. The auxiliary conductive wire is wrapped in a spiral shape, and the auxiliary conductive wire is passed through the heat-sensitive resin material.

[Effect]

According to the configuration of the present invention, a thermosensitive resin material is interposed between the heating line that also serves as a temperature detection electrode and the auxiliary conductive wire, and a thermosensitive resin material is interposed between the auxiliary conductive wire and the temperature detection electrode. , the thermosensitive resin material is interposed twice in series between the heat generation line and the temperature detection electrode. As a result, the impedance between the heating line and the temperature detection electrode can be doubled without increasing the radial thickness of the thermosensitive resin material.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 3 to 5. In other words, this thermosensitive heating element is
As shown in FIGS. 3 and 4, a belt-shaped heating line made of aluminum foil or the like that also serves as a temperature detection electrode is formed on the outer surface of a tube-shaped heat-sensitive resin material 1 made of a polyamide-based material or the like that exhibits negative temperature-impedance characteristics. The band-shaped temperature detection electrodes 2' made of a conductive material such as aluminum foil, which are the same as those in 3, are separated from each other and arranged in a spiral shape, and the auxiliary conductive wire 16 is passed through the heat-sensitive resin material 1. The outer surface of the material 1 is covered with an insulating material 4 to form a cord shape.

This heat-sensitive heating element generates heat by supplying power to both ends of a heat-generating line 3 facing both edges of a heat-sensitive resin material 1.
Similarly, by applying a high frequency voltage between one end of the heating line 3 facing one end of the thermosensitive resin material 1 and one end of the temperature detection electrode 2' with a circuit configuration as shown in the above-mentioned FIG. 2, the heating line 3 and The impedance of the thermosensitive resin material 1 between both terminals of the temperature detection electrode 2' is detected, and the temperature is controlled accordingly.

With this configuration, due to the presence of the auxiliary conductive wire 16 that penetrates the tube-shaped thermosensitive resin material 1,
The voltage applied between the heating line 3 and the temperature detection electrode 2' is applied between the temperature detection electrode 2' and the auxiliary conductive line 16 facing the temperature detection electrode 2'. The fourth voltage is divided between the heating line 3 facing the auxiliary conductive line 16, and the heating line 3 facing the auxiliary conductive line 16.
A partial voltage electric field path P as shown by imaginary lines in the figure is given, and if the thickness of the thermosensitive resin material 1 in the radial direction is r, then the heating line 3 and the temperature sensing electrode 2'
The partial voltage electric field path P between the two is given the same impedance as when the thermosensitive resin material 1 with a thickness of 2r is interposed, and the same impedance is given to the conventional structure shown in FIG. However, in this embodiment, it is necessary to use a thermosensitive resin material 1 with a thickness of 2r, but in this embodiment, it is possible to use a thermosensitive resin material 1 with half the thickness, and the heating line 3 and temperature detection can be performed without impeding flexibility. Sufficient impedance can be provided between the electrode 2' and the temperature detection accuracy.

In addition, as the heat generation line 3 generates heat, the impedance of the region of the heat-sensitive resin material 1 near the heat-generating line 3 decreases before other regions; Since a structure is not adopted in which the heating line 3 and the temperature detection electrode 2' are arranged opposite to each other, the impedance of the area of the thermosensitive resin material 1 near the temperature detection electrode 2' does not change sufficiently at that point, and the heat sensitive If temperature control is performed in response to a local temperature rise before the temperature of the entire area of the resin material 1 has risen sufficiently, the temperature can be controlled uniformly over the entire area without causing any inconvenience. .

Furthermore, since the heating line 3 and the temperature sensing electrode 2' are arranged side by side on the same surface of the thermosensitive resin material 1, when the heating line 3 and the temperature sensing electrode 2' are formed by etching, , the area of the conductive surface material such as aluminum foil to be eluted is reduced accordingly, the etching process can be carried out in a short time, and the utilization efficiency of the conductive surface material is improved.

Since the heating line 3 and the temperature detection electrode 2' arranged in parallel are densely distributed on the surface of the thermosensitive resin material 1, they act as a reinforcing material for the thermosensitive resin material 1, and the resistance strength of the thermosensitive heating element is increased. It is also possible to improve the

〔Effect of the invention〕

According to the heat-sensitive heating element of the present invention, a strip-shaped heating line that also serves as a temperature detection electrode and a strip-shaped temperature detection electrode are separated from each other and arranged on the outer surface of a tube-shaped thermosensitive resin material whose impedance changes according to temperature changes. Since the auxiliary conductive wire is passed through the heat-sensitive resin material in a spiral shape, the impedance of the heat-sensitive resin material interposed between the heating line and the temperature detection electrode can be adjusted to a sufficient level without increasing the thickness. The temperature can be set to a large value, and the temperature can be controlled with high precision without impeding flexibility.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view showing an example of the configuration of a conventional heat-sensitive heating element, Fig. 2 is a circuit diagram showing a temperature control circuit of the heat-sensitive heating element of Fig. 1, and Fig. 3 is an embodiment of the present invention. FIG. 4 is a partially cutaway perspective view showing the configuration of an example, FIG. 4 is a sectional view of the same, and FIG. 5 is a sectional view of a conventional example. 1...Thermosensitive resin material, 2'...Temperature detection electrode, 3
...Heating line, 16...Auxiliary conductive line.

Claims (1)

[Claims] 1. A tube-shaped heat-sensitive resin material whose impedance changes according to temperature changes, a band-shaped heat-generating line that doubles as a temperature detection electrode wrapped spirally around the outer surface of the heat-sensitive resin material, and the A heat-sensitive heating element comprising: a band-shaped temperature detection electrode wound spirally in a state separated from and lined up with a heat-generating line; and an auxiliary conductive wire passing through the heat-sensitive resin material.