JP2878419B2 - Heating element - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heating element mainly used for a floor heating device such as an electric carpet and an electric floor heater.

(Prior Art) Conventionally, a self-temperature control type heating element composed of a pair of electrodes having a material having a positive temperature coefficient of resistance and a large value sandwiched therebetween has been used as an electric carpet or an electric floor heater. Is used as a heating element. In this heating element, heat is generated by a current flowing between the pair of electrodes through a layer of a material having a positive temperature coefficient of the resistance and having a large value (hereinafter abbreviated as a PTC material). At this time, for example, when a local heat-insulating portion occurs, the temperature of the portion increases, and the resistance of the PTC material layer increases, so that the amount of heat output from the portion decreases. That is, by using the above-described heating element, the local temperature of the heat insulating portion of the heating element can be automatically controlled.

(Problems to be Solved by the Invention) Such a method of connecting a heating element to a power supply is intended to make the voltage applied between the electrodes uniform so that an electrode at one end of the heating element is connected to the electrode. Is a method of connecting the other electrode at the other end to a power source (hereinafter abbreviated as a cross connection method)
In addition, there is known a method of connecting all the electrodes at one end of the heating element and all the electrodes at the other end to a power supply (hereinafter, abbreviated as a short connection method). However, even if such a connection method to the power supply is used, unless the resistance value of the electrode can be reduced to zero, the voltage applied between the power supplies will always be lower than the power supply voltage near the center of the heating element, and the PTC material Calorific value decreases. In addition, the calorific value of the electrode becomes smaller toward the center of the heating element, similarly to the calorific value of the PTC material. Therefore, there is a problem that the heat generation amount distribution of the heating element is higher at the terminal portion and lower at the center portion.

The present invention has been proposed in order to improve the above-mentioned disadvantages, and its purpose is to provide a planar heating element even when the heating value distribution of the heating element is higher in the terminal portion and lower in the center portion. An object of the present invention is to provide a heating element that can make the distribution of the heat generation amount substantially uniform.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, when a heating element is wired to form a planar heating element, both ends and a central portion of the heating element are arranged at the same point of a power supply. Then, the heating element is folded at a portion corresponding to 1/4 and 3/4 of the entire length of the heating element, and the folded portion is arranged at the same point. Further, four heating elements connecting the two points are arranged in parallel.

(Operation) According to the above configuration, in the present invention, when a heating element in which a plurality of electrodes are opposed to each other via a PTC material is connected to a power supply by a cross connection method or a short connection method to generate heat, the terminal portion generates heat. Although the amount increases and the calorific value decreases at the center, the both ends and the central part of the heating element are arranged at the same point of the power supply, and the portions corresponding to 1/4 and 3/4 of the total length of the heating element are turned over. Since the folded portions are arranged at the same point and the four heating elements connecting the two points are arranged in parallel, the distribution of the calorific value when the sheet heating element is formed can be made substantially uniform. Having.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

2 (a), 2 (b) and 2 (c) show a schematic configuration of a heating element used in the present invention. In the drawing, a heating element has a structure in which a space between a plurality of opposed electrodes 1 is filled with a PTC material 2 and the periphery thereof is covered with an insulating material 3. When a constant voltage is applied between these electrodes 1, a current flows through the PTC material 2 to generate heat. Due to this heat generation, the temperature of the PTC material 2 rises, the resistance value of the PTC material 2 gradually increases, and conversely, the current decreases.
Eventually, the heat generation amount and the heat radiation amount of the PTC material 2 become the same. This stable temperature is governed by the positive temperature resistance characteristic of the PTC material 2.

FIG. 2 (b) shows an example in which three electrodes are provided, and FIG. 2 (c) shows an example in which an electrode 1 is wound around a core wire 4, a PTC material 2 is coated on the electrode 1, and an electrode 2 is provided on the PTC material 2. Is wound, and the outside is covered with the insulating material 3.

FIGS. 3A and 3B show two types of connection methods for making the voltage between the electrodes of the heating element as uniform as possible. FIG. 3 (a) shows a cross connection method, and shows a method of connecting the electrode 1a at one end of the heating element and the electrode 1b at the other end to terminals having different power supplies, and FIG. 3 (b) And a method of connecting all the electrodes at one end of the heating element and all the electrodes at the other end to a power supply.
However, even when such a connection method is used, the voltage between the electrodes of the heating element is not completely uniform.

FIG. 4 shows the distribution of the voltage between the electrodes in the case of the cross connection method, in which the horizontal axis represents the length of the heating element and the vertical axis represents the potential difference. FIG. 5 shows a calorific value distribution in the case of the cross connection method. The horizontal axis indicates the length of the heating element, and the vertical axis indicates the amount of heat generated. The distribution of the calorific value increases as the distance from the terminal portion increases, and decreases as the distance from the center portion increases. Therefore, the terminal part and the central part are arranged at the same point (one terminal of the power supply), and
If a portion corresponding to (3) and (3/4) is arranged at the same other point (the other terminal of the power supply), a surface heating element having a substantially uniform distribution of the amount of generated heat can be obtained.

FIG. 1 shows a perspective view of an electric carpet to which the wiring method of the present invention is applied. C indicates a controller, and W indicates a power cord. In the heating element H, the terminal portion and the central portion are arranged at the same point of the power supply, portions corresponding to 1/4 and 3/4 of the total length of the heating element are arranged at other points of the power supply, and the four sections connecting the two points are provided. Heating elements are arranged in parallel. The heating elements are arranged such that the temperature of the surface of the electric carpet wired at regular intervals becomes uniform. Both ends of the heating element H are connected to a controller C, and the controller C is provided with a power cord W for obtaining commercial power.

(Effects of the Invention) As described above, according to the present invention, at least two or more electrodes are arranged to face each other, and a heating element having a material having a positive temperature coefficient of resistance sandwiched between the electrodes is wired to form a planar surface. When a heating element is formed, both ends and the center of the heating element are arranged at the same point of the power supply, and the folded portions corresponding to the entire length 1/4 and 3/4 of the heating element are arranged at the same point, and Since the four heating elements connecting the two points are arranged in parallel, there is an effect that the calorific value of the planar heating element can be made substantially uniform on the front surface.

[Brief description of the drawings]

FIG. 1 is a perspective view of an electric carpet when the heating element of the present invention is applied, FIGS. 2 (a), (b) and (c) show the configuration of a heating element, and FIG. a) and (b) show the method of connecting the heating elements, FIG. 4 shows the distribution of the voltage between the electrodes in the cross connection method, and FIG. 5 shows the heat generation distribution in the cross connection method. 1. Electrodes, 2. PCT materials, 3. Insulating materials.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H05B 3/02-3/82

Claims (1)

(57) [Claims] 1. A heating element comprising at least two electrodes arranged opposite to each other and a heating element having a material having a positive temperature coefficient of resistance sandwiched between the electrodes to form a sheet heating element. Both ends and the central part are arranged at the same point of the power supply, and turned over at a part corresponding to 1/4 and 3/4 of the total length of the heating element,
A heating element, wherein the folded portions are arranged at the same point, and four heating elements connecting the two points are arranged in parallel.