JP2006351308A - Surface heating element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface heating element in which changes in electrical property due to moisture absorption of the heat sensitive layer do not affect the surface temperature of a cover which is a basic performance of the surface heating element. <P>SOLUTION: The surface heating element is provided with a heater wire 2 having a heating wire and a detection wire through polyamide resin and a temperature sensor 10 to detect the temperature of this heater wire 2, and both are adhesion fixed by a fastening 11. Thereby, a surface heating element in which a low temperature state of the surface of the cover 4 does not occur due to moisture absorption of the heat sensitive layer 7 and comfortable temperatures can be maintained without improving the material of the heat sensitive layer 7 can be provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a planar heating element such as an electric carpet.

Conventionally, the heater wire used for this type of sheet heating element is wound with a sensing wire made of a copper alloy or the like around the outer periphery of a core yarn made of polyester fiber or the like, and provided with a temperature sensitive layer made of polyamide or the like on the outer periphery. A heating wire made of a copper alloy or the like is wound around the outer periphery, and an insulating layer made of vinyl chloride or the like is provided on the outer periphery for the purpose of insulation (see, for example, Patent Document 1).
JP 2001-192552 A

  However, in the conventional structure, the temperature sensitive layer has high hygroscopicity, and electrical characteristics change greatly during moisture absorption, and it is difficult to perform accurate temperature control in the moisture absorbed state. And a conductivity-imparting material and an ion transfer hindering agent that inhibits the migration of hydrophilic ions, and the sensitivity of water molecules that are hydrophilic by the ion transfer hindering agent dispersed inside the temperature sensitive layer. By inhibiting the approach to the temperature layer, a temperature-sensitive layer having no change in electrical characteristics due to moisture absorption is obtained.

  The present invention solves the above-mentioned conventional problem, and without changing the material of the temperature sensitive layer, the change in the electrical characteristics due to the moisture absorption of the temperature sensitive layer is the cover surface temperature that is the basic performance of the planar heating element. An object of the present invention is to provide a planar heating element that does not affect the surface heating element.

  In order to solve the conventional problems, the planar heating element of the present invention includes a heater wire having a heating wire and a detection wire via a polyamide resin, and a temperature sensor for detecting the temperature of the heater wire. It is.

  This provides a planar heating element that maintains a comfortable temperature without generating a low cover surface temperature due to moisture absorption of the temperature sensitive layer without improving the material of the temperature sensitive layer.

  The planar heating element of the present invention can maintain a comfortable temperature without causing a low cover surface temperature due to moisture absorption of the temperature-sensitive layer.

  According to a first aspect of the present invention, there is provided a sheet heating element including a heater wire having a heating wire and a detection wire via a polyamide resin, and a temperature sensor for detecting the temperature of the heater wire, thereby providing a material for the temperature sensitive layer. Therefore, the present invention provides a planar heating element that maintains a comfortable temperature without generating a low cover surface temperature due to moisture absorption by the temperature-sensitive layer.

  In particular, according to the second invention, in the first invention, the heater wire and the temperature sensor are brought into close contact with each other by a fixture, so that the temperature sensor according to an external load (which is a planar heating element and is stepped on from the upper surface). By covering the breakage and the fixture with a material having good heat conduction, the heat of the heater wire is accumulated, and the temperature of only the temperature sensor portion does not increase, so that the accurate temperature of the heater wire can be detected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment)
The figure shows a planar heating element in an embodiment of the present invention.

  As shown in FIG. 1, the sheet heating element according to the present embodiment has a heater wire 2 which is a cord-like tubing heater folded back on a surface material 1 made of nonwoven fabric, and felt or urethane or the like is disposed below the heater wire 2. The cover 4 with good design located on the surface material 1 is warmed and the human body seated on the cover 4 is warmed while disposing the heat insulating material 3 composed of

  As shown in FIG. 2, the heater wire 2 has a sensing wire 6 made of a copper alloy or the like wound around the outer periphery of a core yarn 5 made of polyester fiber or the like, and a temperature sensitive layer 7 made of polyamide and a polyamide mixture around the outer periphery. The heating wire 8 made of a copper alloy or the like is wound around the outer periphery, and the insulating layer 9 made of vinyl chloride or the like is provided on the outer periphery for the purpose of insulation.

  Further, as shown in FIGS. 1 and 3, the heater wire 2 includes a temperature sensor 10 that is in close contact with the heater wire 2 and detects the temperature thereof. The temperature sensor 10 is covered with a fixture 11 made of a material having good heat conductivity, for example, a metal material, and is positioned and fixed in close proximity to the controller 12. The energization of the heater wire 2 is controlled by the controller 12.

  In the above configuration, when an alternating current flows through the heating wire 8, the temperature of the heater wire 2 rises and the impedance of the temperature sensitive layer 7 changes corresponding to the temperature. By detecting this change in impedance of the temperature sensitive layer 7 between the heating wire 8 and the detection wire 6, the controller 12 turns on and off the heater wire 2 to control the temperature.

  In addition, when a part of the heater wire 2 is kept warm by a cushion or the like and the temperature rises abnormally, the temperature-sensitive layer 7 is melted (high temperature and low viscosity meltability), and it is detected that the heating wire 8 and the detection wire 6 are in contact with each other. The controller 12 stops energization and does not lead to smoke or ignition (the detection wire 6 has a large resistance value, so that no dangerous current flows even if short-circuited with the heating wire 8) ). Further, since this function is provided by the heater wire 2 itself, it functions regardless of which part is kept warm (not a point sensor). Further, even if the temperature is raised abnormally by a cushion or the like, the insulating layer 9 may be made of a material having a melting point higher than that of the temperature-sensitive layer 7, so that the insulating layer 9 melts and the heating wire 8 is exposed. Therefore, the risk of electric shock is prevented and safety is improved.

  The temperature sensitive layer 7 is made of a polymer material and utilizes the temperature dependence of the electrical characteristics of the polymer material. Here, the polymer material for temperature control includes (1) high temperature dependence of electrical characteristics, (2) heat resistance stability of electrical characteristics and mechanical strength, and (3) thermal fuse, that is, high temperature and low viscosity. Properties such as meltability, (4) low hygroscopicity, or electrical properties do not change upon moisture absorption are required.

  Here, what kind of trouble occurs in the planar heating element when the temperature-sensitive layer 7 of the heater wire 2 absorbs moisture will be described with reference to FIG. In the figure, the horizontal axis represents the cover surface temperature, and the vertical axis represents the impedance (kΩ) of the temperature sensitive layer 7 between the heating wire 8 and the detection wire 6 detected by the controller. In the figure, line A represents the relationship between the surface temperature and impedance of the cover 4 when the temperature-sensitive layer 7 is completely dry, and line B represents the relationship between the surface temperature and impedance of the cover 4 when the temperature-sensitive layer 7 absorbs moisture. Represents.

From this figure, during normal dryness (line A), when the controller 12 determines that the impedance of the temperature sensitive layer 7 between the heating wire 8 and the detection wire 6 is 300 kΩ, it controls energization to the heater wire 2. This keeps the surface temperature of the cover 4 at 46 ° C. However, when the heater wire 2 absorbs moisture (line B) and the impedance is 300 kΩ, which is determined by the controller 12, the cover 4 surface temperature is kept at 40 ° C., the cover 4 surface temperature becomes low, and a slippery state occurs. This impedes the heating function of the sheet heating element.

  Here, the controller 12 detects the impedance 300 kΩ of the temperature sensing layer 7 between the heating wire 8 and the detection wire 6 of the heater wire 2, and 78 ° C. by the temperature sensor 10 (the cover surface temperature has a temperature gradient of 40 ° C. The controller 12 determines that the heater wire 2 absorbs moisture, and sets the impedance judgment level of the temperature sensing layer 7 between the heating wire 8 of the heater wire 2 and the detection wire 6 to 100 kΩ. By controlling the temperature of the heater wire 2 to 90 ° C., the cover 4 surface temperature can be controlled to a comfortable 46 ° C.

  Naturally, when the impedance of 300 kΩ is detected, if the temperature sensor 10 detects 90 ° C. (the surface temperature of the cover 4 has a temperature gradient of 46 ° C.), the heater wire 2 is completely dry. The state is determined and the control is performed with the impedance of 300 kΩ as it is. Here, when the temperature of the heater wire 2 is between 78 ° C. and 90 ° C. when the impedance of 300 kΩ is detected, the temperature of the heater wire 2 is set to 90 ° C. (cover surface temperature 46 ° C.) by calculation. Control so as to control with a simple impedance. With such a configuration, it is possible to provide a planar heating element that maintains a comfortable temperature that does not cause a low cover surface temperature due to moisture absorption of the temperature-sensitive layer 7.

  It should be noted that the temperature sensor 10 is kept near the controller 12 so that the lead wire of the temperature sensor 10 can be shortened and the probability that a person will sit near the controller 12 is low. Therefore, an accurate temperature of the heater wire 2 can be obtained.

  Further, when the fixing rod 11 of the present embodiment is made of a material having good heat conductivity and strength, the temperature sensor 10 is not damaged by an external load (because it is a planar heating element and can be stepped on from the upper surface), and the heater The temperature of the wire 2 does not accumulate and the temperature of only the temperature sensor 10 does not increase, and the accurate temperature of the heater wire 2 can be detected.

  As described above, the planar heating element according to the present invention does not generate a low cover surface temperature due to moisture absorption by the temperature-sensitive layer, and can maintain a comfortable temperature. Applicable.

The perspective view of the planar heating element in embodiment of this invention Partial side view showing the heater wire of the coplanar heating element The perspective view which shows the fixed state of the heater wire and temperature sensor of a coplanar heating element The graph which shows the relationship of the impedance of the temperature sensing layer detected between the heating wire of a heater wire and a detection wire in the same surface heating element, the cover surface temperature, and the heater wire temperature

Explanation of symbols

2 Heater wire 6 Detection wire 8 Heating wire 7 Insulating layer 10 Temperature sensor 11 Fixing tool

Claims (2)

A planar heating element comprising a heater wire having a heating wire and a detection wire via a polyamide resin, and a temperature sensor for detecting the temperature of the heater wire. The planar heating element according to claim 1, wherein the heater wire and the temperature sensor are brought into close contact with each other by a fixture.

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