JPH11273832A - Sheet-shaped heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet shaped heater which is capable of preventing spreading fire caused by discharge noise and arc when short-circuited by dividing a heater wire and a short-circuit wire into two sections respectively, connecting them in series to a power source, and by making small the potential difference between the heater wire and the short-circuit wire. SOLUTION: In a sheet-shaped heater, in which a heater consisting of a heater wire 6 wound around a winding core and a short-circuit wire 8 and wound spirally around the same axis with a temperature sensitive layer 7 intervened between itself and the heater wire 6, while generating heat by electrically connecting to a power source 4a, is sandwiched between front texture and back texture and is arranged in meandering manner, the heater wire 6 and the short-circuit wire 8 are divided into two sections respectively, both intermediate points of either one of the heater wire 6 or the short-circuit wire 8 are connected each other, both outer ends of another one are connected each other, they are connected in series to the power source 4a and are connected in parallel each other, so that the direction of the electric current passing through the heating wire 6 and the short-circuit wire 8 respectively is reversed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar heating device such as an electric carpet, an electric blanket, and an electric panel heater, and more particularly to a winding structure of a heating wire and a short-circuit wire.

[0002]

2. Description of the Related Art As shown in FIGS. 2, 4A, 5, 6 and 7, a conventional planar heating device such as an electric carpet has a body 21 having a built-in heating element 22 which generates heat when energized.
And a control unit 23 including a control circuit for controlling the temperature of the main body 21 by controlling the amount of electricity supplied to the heating element 22 and a safety protection device. The control unit 23 has a power supply plug 24 connected thereto. I have. The heating element 22 spirally winds a heating wire 26 around a winding core 25 made of polyester fiber or the like, coats a heat-sensitive layer 27 made of nylon or the like thereon, and forms a short-circuit wire 28 on the heat-sensitive layer 27. And a cover insulating layer 29 made of vinyl chloride or the like is coated thereon.

The heating element 22 is sandwiched between a front cloth and a back cloth and arranged in a meandering manner, and one end of a heating wire 26 is connected to a power switch 3.
0 and the relay contact 31 are connected in series to the power supply 24a, the other end is connected to the power supply 24a by connecting the current fuse 32 and the temperature fuse 33 in series, and the heating element 22 generates heat when energized. When the heating wire 26 is abnormally overheated, the impedance of the heat-sensitive layer 27 covering the heating wire 26 becomes small (or melts), and a short-circuit current flows between the heating wire 26 and the short-circuit wire 28. The connected heating resistor generates heat and passes through the temperature overheating prevention circuit, and the temperature fuse 33
To cut off the power supply circuit.

As shown in FIG. 6, a current Ia flowing through the heating wire 26 and a current Ib flowing through the short-circuit wire 28 flow in opposite directions (opposite phases) to suppress generation of a magnetic field. is there. However, the resistance at the point a at the beginning of the current flow of the heating wire 26 is small and the voltage is high, and at the point b where the current ends, the voltage drops and the voltage decreases. On the other hand, the voltage at point c at the beginning of the current flow of the short-circuit line 28 is high, and the voltage at point d at which the current ends is low. For this reason, FIG.
As shown in (A), the potential difference between ad and bc
When Va becomes large and the heating wire 26 and the short-circuit wire 28 are short-circuited, a large current flows instantaneously, and there is a problem that a discharge sound or a burning by an arc may occur.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has two heating wires and two short-circuit wires.
And connected in series to the commercial power supply, and connected in parallel so that the current flowing directions are opposite to each other, to reduce the potential difference between the heating wire and the short-circuit line, It is an object of the present invention to provide a planar warming device capable of preventing the occurrence of a fire.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a heat-sensitive layer interposed between a heating wire wound around a winding core and the heating wire to form a coaxial cable. A heating element composed of a helically wound short-circuit wire, connected to a commercial power supply and generating heat by energization, is sandwiched between a front fabric and a back fabric, and is arranged in a meandering shape in a planar heating device. The heating wire and the short-circuit wire are each divided into two, and one of the heating wire and the short-circuit wire is connected at both intermediate points, the other is connected at both outer ends, and each is connected in series to the commercial power supply. At the same time, they are connected in parallel so that the directions of the currents flowing through the heating wire and the short-circuit wire are opposite to each other.

[0007] Further, the heat-generating wire and the short-circuit wire divided into two are formed in pairs, and are formed to have the same length.

The heating wire is divided into two parts so that the resistance value between both ends is equal.
Further, the short-circuit line is divided into two such that the resistance value between both ends is equal.

In addition, the potential difference between the opposite ends of each of the two ends of the heating wire and the short-circuit wire is substantially equal.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a planar warming device according to the present invention. FIG. 1 is a schematic external view of a planar warming device such as an electric carpet according to the present invention.
FIG. 3 is an enlarged structural view of a heating element according to the present invention, and FIG. 3 is a main part circuit diagram according to the present invention. In the figure, the basic configuration of the planar heating device is a
And a control unit 3 including a control circuit for controlling the temperature of the main body 1 by controlling the amount of electricity supplied to the heating element 2 and a safety protection device.

In the main body 1, a heating element 2 is arranged in a meandering manner between a front cloth and a back cloth made of fiber cloth, and a terminal portion of the heating element 2 is electrically connected to a control section 3 collectively. And
A power supply plug 4 is connected to the control unit 3.

The heating element 2 includes a heating wire 6 spirally wound around a winding core 5 made of an insulating material such as polyester fiber.
And the heating wire 6 covered with a heat-sensitive layer 7 made of nylon or the like,
A short-circuit wire 8 is spirally wound on the same axis, and a jacket insulating layer 9 made of vinyl chloride or the like is coated thereon.

The heating wire 6 is divided into two heating wires 6a and 6b having substantially equal resistance values at both ends. One end a of the heating wire 6a is connected to a power switch 10 and a relay contact 11 in series to form a power supply 4a. The other end of the heating wire 6a and one end of the heating wire 6b are connected in series at point e, and the other end b of the heating wire 6b is connected to the current fuse 1
2 and the thermal fuse 13 are connected in series and connected to the power supply 4a, so that the heating element 2 generates heat when energized.

The short-circuit line 8 is divided into two short-circuit lines 8a and 8b having substantially equal resistance values at both ends, and a power switch 10 and a relay contact 11 are arranged in series at a point c at the middle side of the short-circuit line 8a. To the power supply 4a, connect the other end f of the short-circuit line 8a and the one end g of the short-circuit line 8b in series, and connect the other end d of the middle side of the short-circuit line 8b to the current fuse 12 and the temperature fuse 13. The current Ia flowing through the heating wire 6 and the current Ib flowing through the short-circuit line 8 are arranged in series and connected to the power supply 4a in opposite directions (opposite phases) to cancel the magnetic field.

When the heating wire 6 is subjected to abnormal overheating or impact, the impedance of the heat-sensitive layer 7 covering the heating wire 6 decreases (or melts), and a short circuit occurs between the heating wire 6 and the short-circuit wire 8. As a result of the flow of the current, the heating resistor connected to the short-circuit line 8 generates heat, so that the temperature fuse 13 is blown through an overheating prevention circuit (not shown) to cut off the power supply circuit.

The heating wire 6a, the short-circuit wire 8a, and the heating wire 6b
And the short-circuit line 8b are wound coaxially in pairs with each other, and the voltage relationship at each point of these lines is shown in FIG. 4 (B). The resistance at the point a at the beginning of the current flow of the heating wire 6 is small and the voltage is high, and the voltage decreases as it goes to the points c and b, and the voltage is the lowest at the point b. On the other hand, the short-circuit line 8 has a high voltage at the point c on the intermediate side where the current starts to flow, and the point f (the same applies to the point g).
The voltage decreases from point d to point d, and the voltage is lowest at point d.

As a result, the potential differences Vb between the points of the heating wire 6 and the short-circuit line 8, that is, a-f, ec, ed, and b-g become substantially equal. The potential difference Va between both ends of the conventional heating wire and the short-circuit wire shown in FIG. As in the above configuration, the heating wire 6 and the short-circuit wire 8 are divided into two, 6a, 6b and 8a, 8b, respectively, so that they are connected in series to the commercial power supply 4a and the phases of currents flowing therethrough are opposite to each other. The heating wire 6 and the short-circuit wire 8 are connected in parallel to reduce the potential difference between the wires at each point, thereby preventing the heating wire 6 from being overheated or shocked, thereby preventing a discharge sound or short-circuit caused by an arc when a short circuit occurs. It becomes a surface heating device that can be used.

[0018]

As described above, according to the present invention, as described above, the heating wire and the short-circuit wire are each divided into two and connected in series to the commercial power supply.
The heating wire 6 and the short-circuit wire are connected in parallel so that the current phases flowing to each other are opposite to each other, and the potential difference between the wires at each point is reduced, so that the heating wire 6 receives abnormal overheating or impact,
This is a planar heater that can prevent discharge noise and short-circuiting due to arcing when a short circuit occurs.

[Brief description of the drawings]

FIG. 1 is a schematic external view of a planar heating device according to the present invention.

FIG. 2 is an enlarged structural view of a heating element according to the present invention.

FIG. 3 is a main part circuit diagram according to the present invention.

4A and 4B are diagrams showing a voltage relationship between a heating wire and a short-circuit line according to the present invention and a conventional example, wherein FIG. 4A is a conventional example and FIG.

FIG. 5 is a schematic external view of a conventional planar heating device.

FIG. 6 is an enlarged structural view of a heating element in a conventional example.

FIG. 7 is a main part circuit diagram in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Heating element 3 Control part 4 Plug 5 Core 6 Heating wire 7 Heat-sensitive layer 8 Short-circuit wire 9 Outer insulation layer 10 Power switch 11 Relay contact 12 Current fuse 13 Temperature fuse

Claims (5)

[Claims] 1. A heating wire wound around a winding core, and a short-circuit wire wound spirally coaxially with a heat-sensitive layer interposed between the heating wire, and connected to a commercial power supply and energized. A heating element that generates heat by sandwiching the heating element between the front cloth and the back cloth and disposing the heating element and the short-circuit line in two. One is connected at both intermediate points, the other is connected at both outer ends, and each is connected in series to the commercial power supply, and the directions of currents flowing through the heating wire and the short-circuit wire are opposite to each other. A planar heating device characterized by being connected in parallel. 2. The planar heating device according to claim 1, wherein the heat-generating wire and the short-circuit wire divided into two are formed in pairs and have equal lengths. 3. The planar heating device according to claim 1, wherein the heating wire is divided into two so that the resistance value between both ends is equal. 4. The planar heater according to claim 1, wherein the short-circuit line is divided into two so that the resistance value between both ends is equal. 5. The planar heater according to claim 1, wherein the potential difference between the two ends of the heat-generating wire and the short-circuit wire, which are opposed to each other, is substantially equal. .