JPH103982A - Heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a generated magnetic field in a heating element formed with a heating film of a resistance heating material on an insulating base material, by eliminating the magnetic field generated by a current with the magnetic field generated by a reverse current. SOLUTION: An Ag or carbon resistance heating material is applied on the plane of a sheet-like insulating base material 1 made of a PET film or the like by coating or pattern printing to form a heating film 2, and a planar heating element is constituted. The film 2 is constituted of a meandering pattern 3 and a pattern 4 arranged in parallel near it, the left end sections of both patterns 3, 4 are short-circuited by a pattern 5, and the right end sections are connected to a temperature adjuster 6. At the time of carrying a current through the patterns 3, 4, the respective current directions are opposite to each other and the generated magnetic fields eliminate each other. The synthetic magnetic field becomes smaller as the distance D between conductors becomes smaller. Both patterns may be formed on both faces of the insulating base material 1, or they may be surface-symmetrically formed on two overlapped sheet-like insulating materials 1 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating element which is applied to an electric heating device such as an electric blanket, an electric blanket, and an electric carpet in which a heater wire is arranged near a human body.

[0002]

2. Description of the Related Art Conventionally, a flat heating element used for an electric heating device such as a carpet is a single linear heating element comprising a resistance heating wire 40 covered with a heat-resistant insulator 39 as shown in FIG. As shown in FIG. 16, the heating element 41 is stretched over a flat heating surface 42 such as a carpet or the like, and electricity is supplied from both ends of the resistance heating wire 40 via a temperature controller 43 so that the linear heating element 41 The human body was warmed by generating heat to the temperature. In recent years, a planar heating element in which a resistive heating material such as an Ag-based or carbon-based material is coated or printed on an insulating base material such as a PET film in a film form has also been developed.

[0003]

It is well known that an alternating magnetic field is generated when an alternating current flows through the above-mentioned conventional heating element. Electric heating devices such as electric carpets have a large heating surface and it is difficult to completely shield the magnetic field.
There is a risk of giving noise to AV products such as video and audio electric products. In recent years, it has been reported that this alternating magnetic field has an undesirable effect on the human body. Accordingly, the magnetic field generated from the electric current for electric heating such as an electric blanket has a very low intensity, but it is preferable that the heater wire be of a demagnetizing type.

The present invention has been made to solve the above-described problem, and has as its object to provide a heating element which is used as a heater wire of an electric heater and reduces the generated magnetic field.

[0005]

Electromagnetics are generated around a current-carrying conductor and are generated in a clockwise direction with respect to the direction in which the current flows. The magnetic field has a canceling effect. FIG.
, The magnetic field strength H (A / m) at a point at a distance r (m) from the long straight conductor is

[0006]

(Equation 1)

[0007] Here, I is the current (A / m) flowing through the conductor, and D is the distance (m) between the two conductors. From the above theoretical formula, it is well known that the magnetic field strength H is proportional to the current I, proportional to the distance D between the two conductors, and inversely proportional to the distance r between the two conductors and the detection position. The present invention provides a low-magnetic-wave heating element by using the above-mentioned electromagnetic properties by the following means. (1) A demagnetization effect is achieved by pattern printing, multilayer printing, lamination, etc., of parallel conductors in which electromagnetic waves cancel each other. (2) The heating element is made longer, the current density is suppressed, and the magnetism is reduced. (3) Achieve low magnetism by backing a magnetic shield material or the like using a multilayer coating method that takes advantage of the characteristics of the heat generating film.

Specifically, the invention according to claim 1 is a heating element in which a heating film is formed by coating or printing a resistance heating material on an insulating base material, wherein the heating film is formed by the heating film. It is characterized in that a magnetic field generated by a current flowing in the coating is canceled by a magnetic field generated by a current flowing in the heating film in a direction opposite to the current.

According to a second aspect of the present invention, there is provided a heating element in which a heating film is formed by coating or printing a resistance heating material on a sheet-shaped insulating base material, wherein the heating film comprises two heating films. Are arranged in parallel on the same surface in close proximity to each other, and the direction of the current flowing in one pattern is opposite to the direction of the current flowing in the other pattern. It is.

According to a third aspect of the present invention, there is provided a heating element in which a heating film is formed by coating or printing a resistance heating material on both surfaces of a sheet-shaped insulating substrate, wherein one of the insulating substrates is provided. The heat generating film formed on the surface of the insulating base material becomes plane-symmetric with the heat generating film formed on the other surface of the insulating base material, and the direction of the current flowing through one of the heat generating films and the direction of the current flowing through the other heat generating film are changed. It is characterized in that it is configured to be reversed.

According to a fourth aspect of the present invention, there is provided a heating element in which a heating film is formed by coating or printing a resistance heating material on an outer surface of two sheet-shaped insulating base materials which are superposed on each other. The heat-generating film formed on one insulating substrate is plane-symmetric with the heat-generating film formed on the other insulating substrate, and the direction of the current flowing through one heat-generating film and the direction of the current flowing through the other heat-generating film Are configured to be reversed.

The invention described in claim 5 is the first invention.
The invention according to any one of the first to fourth aspects, characterized in that a magnetic shield material is provided on the back side of a wiring portion for supplying a current to an electrode connected to the heat generating film.

According to a sixth aspect of the present invention, a heating film is formed by coating or printing a resistance heating material on a long tape-shaped insulating substrate so as to extend in the longitudinal direction of the insulating substrate. In addition, electrodes are provided on both sides in the longitudinal direction of the heat generating film so as to extend in parallel with the heat generating film.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electric carpet will be described below with reference to the drawings.

First, a first embodiment of the present invention will be described with reference to FIG. As shown in the drawing, a resistance heating material such as an Ag-based or carbon-based material is pattern-printed on the plane of a sheet-shaped insulating base material 1 made of a PET film or the like covering the entire surface of a flat heating element of a carpet. The heating film 2 is formed. The heating film 2 has a meandering pattern 3
And a pattern 4 disposed in parallel with and close to the pattern 3. The left end of the pattern 3 and the pattern 4
Is short-circuited with a pattern 5 and the right ends of the patterns 3 and 4 are connected to a temperature controller 6. When the temperature controller 6 is energized, current flows in the patterns 3 and 4 in opposite directions as indicated by arrows, and the magnetic field generated by the current flowing through the pattern 3 is canceled by the magnetic field generated by the current flowing through the pattern 4.

FIG. 2 is an explanatory diagram for explaining the principle of demagnetization. The composite magnetic field at point P of the vector a of the magnetic field generated by the current flowing in the conductor A and the vector b of the magnetic field generated by the current flowing in the conductor B in the opposite direction is c. As the distance D between the conductors A and B increases, the angle e between the vectors a and b decreases and the combined magnetic field c increases, and ultimately approximates the sum of the absolute value of the vector a and the absolute value of the vector b. . Conversely, as the inter-conductor distance D decreases, the angle e increases and the resultant magnetic field c decreases. When the distance D between the conductors is 0, the directions of the vectors a and b are reversed, and the combined magnetic field c is 0. Therefore, it is preferable that the distance d between the pattern 3 and the pattern 4 in FIG. 1 is smaller, and the pattern 3 is printed on the insulating substrate 1 according to the sheet resistance of the heating element.

FIG. 3 is a plan view of a heating element which uses the above principle to reduce the generated magnetic field. The same parts as those in the first embodiment are denoted by the same reference numerals. In this heating element, a heating film 7 is formed by pattern-printing a resistance heating material on a plane of the insulating base material 1. The heating film 7 has a top 8a and a side 8b orthogonal to the top 8a.
It is composed of a letter-shaped pattern 8 and a meandering pattern 9 arranged inside the pattern 8. The plurality of tops 9a of the pattern 9 are parallel to the tops 8a of the pattern 8, and one side 9b of the pattern 9 is
It is parallel to. The left end of the pattern 8 is short-circuited to the left end of the pattern 9, and the right ends of the patterns 8 and 9 are connected to the temperature controller 6. Current flows in the direction of. The magnetic field generated by the current flowing in the pattern 8 is the pattern 9
Are canceled by the magnetic field generated by the current flowing through the top 9a and the one side 9b of the first. Further, since the pattern 9 has a meandering shape, the magnetic field generated by the current flowing in the pattern 9 is canceled by the magnetic field generated by the current flowing in the pattern 9 in the opposite direction.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the heating films 11 and 12 are formed so as to be plane-symmetric by printing or coating a resistance heating material on both surfaces of the sheet-shaped insulating base material 10. One end of the heat generating film 11 and one end of the heat generating film 12 located on the back side thereof are short-circuited by the conductor 13. Electrodes 14 and 15 are provided on the other ends of the heat generating films 11 and 12, respectively.
Is connected to the temperature controller 16. When the temperature controller 16 is energized, currents in opposite directions flow through the heat generating films 11 and 12 as indicated by arrows, and the magnetic field generated by the current flowing through the heat generating film 11 is canceled by the magnetic field generated by the current flowing through the heat generating film 12. . In this case, the inter-conductor distance D shown in FIG. 2 corresponds to the thickness t of the insulating base material 10. For example, when t is an extremely small value such as 125 μ, a large demagnetizing effect can be expected. The heating films 11 and 12
The shape of is not particularly limited, and can be applied to, for example, a case of a heating film on the entire surface.

FIG. 5 shows data obtained by measuring the magnetic field generated by the heating element shown in FIG. 4 with an ultrasonic environment measuring instrument and comparing it with the magnetic field generated by the conventional heating element (code heater) shown in FIG. The ultrasonic environment measuring instrument used was a micro ELF (trade name) manufactured by Arnu Medical Instruments Co., Ltd., the measurement distance was 0 mm, and the current flowing through the conductor was 1 A.

Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, the heating film 1 is formed by coating or printing a resistance heating material on the outer surfaces of the two insulating substrates 17 and 18 which are overlapped with each other.
9 and 20 are formed. Heat generation film 19 and heat generation film 2
0 is formed to be plane symmetric,
Is short-circuited by a conductor 21 at one end of the heat-generating film 20 located on the back side thereof. In addition, the heating films 19, 2
0, electrodes 22 and 23 are provided at the other end.
3 is connected to the temperature controller 24. Temperature controller 24
When current flows through the heating films 19 and 20, current flows in opposite directions as indicated by arrows, and the magnetic field generated by the current flowing through the heating film 19 is canceled by the magnetic field generated by the current flowing through the heating film 20.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, the conductor for short-circuiting the heat generating films 11 and 12 of the heat generating element of the second embodiment is constituted by a copper foil electrode tape with a conductive adhesive. That is, one end of the copper foil electrode tape 25 is attached to the heat generating film 11, and the other end is bent to the back surface side of the insulating base material 10 and is attached to the heat generating film 12. In this case, productivity is high and reliability is high. The same effect can be obtained when the conductor for short-circuiting the heat generating films 19 and 20 of the heat generating body of the third embodiment is formed of a copper foil electrode tape.

Next, a fifth embodiment of the present invention will be described with reference to FIG. In this embodiment, the insulating base 26
A heating film 27 and an electrode 28 are formed thereon by printing, and a wiring routing section 29 for flowing a current to the electrode 28 is formed.
The magnetic shield material 30 is provided on the back surface of the magnetic head. It is difficult to magnetically shield the entire surface of a flat heating element such as a carpet. On the other hand, as shown in FIG. 9, the magnetic field is concentrated in the routing section 29. Therefore, a magnetic shield material 30 made of a material as shown in Table 1 is provided only on the routing portion 29 by printing, coating, or laminating a sheet to efficiently and economically demagnetize.

[0023]

[Table 1]

Next, a sixth embodiment of the present invention will be described with reference to FIG. In this embodiment, the magnetic shield member 30 in the fifth embodiment is obtained by laminating a plurality of sheet-like shield members 30a to 30c. FIG.
Are data comparing the demagnetizing effects of a magnetic shield material of the same thickness, one made of one sheet and the other made of two sheets laminated. In addition,
The material is a high magnetic permeability cobalt-based amorphous alloy sheet. As shown in this data, it is said that laminating a plurality of sheets has a higher demagnetizing effect than increasing the thickness of the magnetic shield material. This embodiment is an application of this.

Next, a seventh embodiment of the present invention will be described with reference to FIG. In this embodiment, a high-resistance, for example, 20 mm
A belt-like heating film 32 of kΩ / cm ² is provided by printing or coating, and electrodes 33, 33 extending in parallel with the heating film 32 are provided on both longitudinal sides of the heating film 32. In this heating element, the current flows in the direction of the arrow, and the equivalent circuit is a parallel resistance circuit in which a plurality of resistors 34 are connected in parallel as shown in FIG. 13, and the current is dispersed, so that the current density can be reduced. The generated magnetic field is small. For example, when a long tape-like heating element having a resistance value of 10 mm and a heating film having a width of 10 mm is stretched over a flat heating surface of a carpet or the like and energized at 100 V, the combined power becomes about 250 W /
2.5 A, but the current per cm of electrode is about 5 mm
A is reduced to 1/500 and the generated magnetic field can be extremely suppressed. Further, in this heating element, electrodes 33, 33 extending in parallel with the heating film 32 are provided on both sides in the longitudinal direction of the long heating film 32, and a current flows in a direction orthogonal to the heating film 32. Even if a part is damaged, it does not become a non-energized state.

Next, an eighth embodiment of the present invention will be described with reference to FIG. In this embodiment, a long tape-shaped heating element 35 having a heating film having PTC characteristics in the heating element of the seventh embodiment is arranged in a meandering manner on a heating surface 36 of a carpet. When this carpet is used, the temperature load section 37 surrounded by a broken line reduces the resistance value of the PTC characteristic due to a decrease in temperature, increases the power, and attempts to return the temperature to self. Further, in the portion 38 without load, there is no change in temperature and power, and no wasteful power is consumed. Further, even if abnormal heat generation occurs in a part of the heating element 35, the power in that part is suppressed by the PTC characteristic, which is safe.

[0027]

As described above, according to the heating element of the present invention, the leakage magnetic field generated by the supplied current is significantly reduced, so that other electric devices are adversely affected and the human body is exposed to the electromagnetic field. Adverse effects on health can be avoided.

[Brief description of the drawings]

FIG. 1 is a plan view showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the principle of demagnetization according to the present invention.

FIG. 3 is a plan view showing a schematic configuration of a second embodiment of the present invention.

FIG. 4 is a side view showing a schematic configuration of a third embodiment of the present invention.

FIG. 5 shows data for explaining a degaussing effect.

FIG. 6 is a side view showing a schematic configuration of a fourth embodiment of the present invention.

FIG. 7 is a side view showing a schematic configuration of a fifth embodiment of the present invention.

FIG. 8 is a plan view and a side view showing a schematic configuration of a sixth embodiment of the present invention.

FIG. 9 is a view showing a distribution of a generated magnetic field when a magnetic shield material is removed from the heating element of FIG. 7;

FIG. 10 is a side view showing a schematic configuration of a seventh embodiment of the present invention.

FIG. 11 is data for explaining an effect when a magnetic shielding material is formed by laminating a plurality of thin film sheets.

FIG. 12 is a plan view showing a schematic configuration of an eighth embodiment of the present invention.

FIG. 13 is an explanatory diagram for explaining the structure of the heating element of FIG. 12;

FIG. 14 is a plan view showing a schematic configuration of a ninth embodiment of the present invention.

FIG. 15 is a cross-sectional view of a conventional heating element.

FIG. 16 is a plan view showing a schematic configuration of a conventional electric warmer provided with a heating element.

[Explanation of symbols]

 1 Insulating plate 2, 3 Heat generation film

Claims (6)

[Claims] 1. A heating element having a heating film formed by coating or printing a resistance heating material on an insulating base material, wherein the heating film generates a magnetic field generated by a current flowing through the heating film. A heating element configured to be canceled by a magnetic field generated by a current flowing in a direction opposite to the current in the film. 2. A heating element in which a heating film is formed by coating or printing a resistance heating material on a sheet-like insulating base material, wherein the heating film brings two patterns close to each other on the same surface. The heating element is arranged so that the direction of the current flowing in one pattern is opposite to the direction of the current flowing in the other pattern. 3. A heating element in which a heating film is formed by coating or printing a resistance heating material on both surfaces of a sheet-shaped insulating substrate, wherein the heating film formed on one surface of the insulating substrate is The heat-generating film formed on the other surface of the insulating substrate is plane-symmetrical, and the direction of the current flowing through one heat-generating film is opposite to the direction of the current flowing through the other heat-generating film. Characteristic heating element. 4. A heating element in which a heating film is formed by coating or printing a resistance heating material on an outer surface of two sheet-shaped insulating base materials which are superimposed on each other,
The heat-generating film formed on one insulating base material is plane-symmetric with the heat-generating film formed on the other insulating base material, and the direction of the current flowing through one heat-generating film and the direction of the current flowing through the other heat-generating film are different. A heating element characterized by being configured to be reversed. 5. The heating element according to claim 1, wherein a magnetic shield material is provided on the back side of a wiring portion for passing a current to an electrode connected to the heating film. 6. A heating film is formed on a long tape-shaped insulating base material by coating or printing a resistance heating material so as to extend in the longitudinal direction of the insulating base material. A heating element comprising an electrode extending in parallel with the heating film.