JP2005026045A - Flat heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat heater that can raise an impressed voltage, and capable of increasing a heating volume per unit area. <P>SOLUTION: The flat heater comprises a plurality of laminated insulation sheets 21, 22, 23 and 24, and a plurality of heater members 11, 12 and 13 interposed between the insulation sheets 21, 22, 23 and 24 and superposed at intervals. An area in which the heater members can be arranged can be increased by superposing the heater members several times over the insulation sheets. There can also be arranged heater members longer than prior art ones in which the heater members are arrayed in a single layer. Further, since the heater members with the same standards as the single-layer flat heaters can be adopted, an allowable current value is unchanged, and the heating volume can be increased. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a planar heater that has a heating surface that extends in a two-dimensional direction and is used in a heat source of a heating device.
[0002]
[Prior art]
A planar heater is obtained by sandwiching a planarly extending heater member between two insulating sheets and integrating them into a sheet (Patent Documents 1 and 2, etc.). For example, as shown in FIG. 3, the heater member 91 is sandwiched between the insulating sheets 92 and 93, and the end portion 94 of the lead wire is connected to the terminal portion 911 and the like of the heater member 91. The heater member 91 is a continuous resistor.
[0003]
Then, when a predetermined voltage is applied from the lead wires connected to both ends of the heater member, a current flows through the heater member, and the heater member is heated by electric resistance heat generation of the heater member. This heat is transferred to the insulating sheet, and the entire planar heater generates heat. Such a planar heater is used by being arranged or embedded in a portion that needs to generate heat in a predetermined area.
[0004]
In a planar heater, in many cases, a lead wire is connected to both ends of a belt-like or linear heater member that is bent and extends in a planar manner with a distance from an adjacent portion, and the heater member is insulated by two sheets. It is sandwiched between sheets.
[0005]
[Patent Document 1] JP 2002-175870 A [Patent Document 2] JP 2002-231426 A
[Problems to be solved by the invention]
By the way, when manufacturing a planar heater with a small heat generation area, a sufficiently long heater member cannot be adopted, and if the applied voltage to the heater member is increased, the allowable voltage that can be passed through the heater member may be exceeded. is there. In such a case, an appropriate voltage has been achieved using a transformer (Slidac (registered trademark), transformer, etc.). Further, in order to increase the calorific value per unit area, it is necessary to increase the resistance value of the heater member and to flow a large current, but there is a limit in the conventional planar heater. In order to solve such a problem, it is possible to solve the problem by changing the length and thickness of the heater member. However, if the length and thickness of the heater member are changed, the current value that can be passed through the heater member (that is, heat generation). There is a problem in that it is necessary to prepare a heater member of a plurality of standards even if it is not possible to cope with the decrease in the amount), or even if it is possible to cope with changes in length and thickness.
[0007]
This invention makes it the subject which should be solved to provide the planar heater which can make an applied voltage high in view of the said situation. Furthermore, it is a problem to be solved to provide a planar heater that can increase the amount of heat generated per unit area.
[0008]
[Means for Solving the Problems]
The planar heater of the present invention that solves the above-described problems includes a plurality of laminated insulating sheets, and a plurality of heater members that are sandwiched between the insulating sheets and stacked with a gap therebetween. (Claim 1). In other words, it is possible to increase the area in which the heater member can be disposed by overlapping the heater member several times through the insulating sheet, more than the conventional planar heater in which the heater member is disposed in a single layer. A long (high resistance value) heater member can be provided. Further, since the same member as the single layer planar heater can be adopted as the heater member, the allowable current value does not change and the heat generation amount can be increased. Further, by controlling the value of the applied voltage and the presence / absence of voltage application for each of the heater members arranged in layers, the amount of heat generated by the entire planar heater can be precisely controlled.
[0009]
The plurality of heater members preferably have terminal portions at both ends, and are connected in series and / or in parallel via the terminal portions. Furthermore, it is preferable that the terminal parts to be connected are arranged in the vicinity, and the insulating sheet has a through hole that penetrates and connects the terminal parts in the vicinity of the terminal part (Claim 3). .
[0010]
As the shape of the planar heater of the present invention, in addition to a planar shape, a shape bent into a cylindrical shape can also be adopted.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The planar heater of this embodiment is composed of a heater member and an insulating sheet. In addition to having a planar shape, this planar heater can be shaped according to the shape of the counterpart member to be heated, such as a cylindrical shape. Furthermore, a temperature sensor etc. can be assembled | attached inside and / or the exterior to this planar heater.
[0012]
A plurality of insulating sheets are used by being laminated. A plurality of heater members are sandwiched between two or more insulating sheets at intervals. When contact is made between unintended portions of the heater member, the resistance value changes, so there is a limit to the amount of heater member that can be disposed per unit area. In the present embodiment, since the heater member is sandwiched between two or more insulating sheets, the limit of the amount that the heater member can be disposed increases.
[0013]
The heater member is an electric resistor that generates heat when energized and is made of a metal having heat resistance. The heater member has a linear shape, a planar shape, etc., and an elongated shape can be preferably employed. The heater member can be formed by bending a wire, punching a sheet material into a bent pattern having a predetermined width, or etching. In the planar heater of the present invention, the conventional heater member can be used as it is or with a slight modification of the conventional heater member.
[0014]
If the plurality of heater members are connected in series as a whole, the limit of the applied voltage of the planar heater can be improved, and if they are connected in parallel, the limit value of the current flowing through the planar heater can be increased. Furthermore, it becomes easy to achieve a heat generation amount and an applied voltage as required by changing the connection between the heater members as necessary.
[0015]
Both ends of the heater member can have terminal portions for supplying power from the outside. Furthermore, a lead wire can be connected to the terminal portion. A terminal part and a lead wire will not be specifically limited if resistance value is smaller than a heater member, A conventional thing can be used as it is. Moreover, the connection of the terminal part of a heater member and a lead wire should just be connected by the method performed normally.
[0016]
The terminal portion is preferably disposed in the vicinity of the other terminal portion to be connected. In this case, it can have a through-hole which penetrates and connects the terminal parts to be connected to the corresponding vicinity of the insulating sheet described later. By providing this through hole in all laminated insulating sheets, the connection between the terminal portions is facilitated. The connection method between the terminal portions is not particularly limited, and a conventional method such as welding can be employed.
[0017]
As for the insulating sheet, a sheet-like member having electrical insulation and heat resistance can be used as in the prior art. It may be either highly rigid or flexible. In addition to the insulating sheet having the necessary insulating performance and strength as a single sheet, it is also possible to improve the flexibility by adopting a stack of a plurality of thinner insulating sheets.
[0018]
【Example】
(Example 1)
Hereinafter, a planar heater according to an embodiment of the present invention will be described with reference to FIGS. In addition, this drawing is a schematic diagram, and there are some portions in which the size and the like of each member are not accurate. As shown in FIG. 1, the planar heater of this embodiment includes heater members 11, 12 and 13, insulating sheets 21, 22, 23 and 24, lead wires 31 and 32, and an electrode part sheet 41.
[0019]
The heater members 11, 12, and 13 are strip-shaped metal foils made of a nickel-chromium alloy, and the thickness thereof is approximately 80 μm and the width is approximately 0.5 mm. Terminal portions are formed at both ends of the heater members 11, 12 and 13. The heater members 13 are arranged in the pattern shown in FIG.
[0020]
In this embodiment, a nickel-chromium alloy is used for the heater member, but other than this, iron-chromium alloy, nickel-iron alloy, SUS, aluminum, platinum, iron, nickel, etc. as conventionally used are used. A heat generating material made of an alloy or a pure metal may be used. The thickness and shape are not particularly limited because they depend on the shape, power consumption, and heat generation distribution of the planar heater, and may be appropriately selected during implementation.
[0021]
The insulating sheets 21, 22, 23, and 24 are each composed of three sheets having the same outer shape, and are sequentially stacked and integrated to form the insulating sheets 21, 22, 23, and 24 without shifting. The three sheets may be bonded or simply overlapped.
[0022]
In FIG. 1, the insulating sheets 21, 22, 23, and 24 are shown as a single sheet-like member. Each of the sheets constituting the sheets 21, 22, 23, and 24 is a mica sheet having a predetermined thickness with a square of 20 mm × 20 mm.
[0023]
As shown in FIG. 2, the insulating sheet 23 is provided with through holes 231 in the vicinity of the terminal portions 131 and 132 of the heater member 13. The through hole 231 is a hole provided to connect the terminal portions 131 and 132 of the heater member 13 to the terminal portions 121 and 122 of the heater member 12. The terminal portions 131 and 121, 132 and 122 are connected by spot welding.
[0024]
Further, the insulating sheet 23 is provided with through holes 232 and 233. The through holes 231, 232 and 233 are also provided at corresponding positions of all the other insulating sheets 21, 22 and 24. A through hole corresponding to the through hole 232 provided in the insulating sheet 22 is a portion connecting the heater members 12 and 11, and a through hole corresponding to the through hole 233 provided in the insulating sheet 21 is a terminal portion of the heater member 11. 111 is provided to extend the surface of the insulating sheet 21. The terminal portion 111 is connected to the end portion 31 of the lead wire by spot welding or the like. That is, the heater members 11 and 12 (not shown) have substantially the same form as the heater member 13 shown in FIG. 2 except that the positions where the terminal portions are provided are different.
[0025]
The reason why the through holes are provided in the corresponding positions of all the insulating sheets 21, 22, 23 and 24 is to facilitate spot welding and the like. Finally, by providing mica sheets constituting the insulating sheet on both sides of the main heater, the risk of short-circuiting of the exposed terminal portions 131 and 132 can be eliminated.
[0026]
In this example, a mica sheet was used as the insulating sheet. However, in addition to the mica sheet, a sheet having electrical insulation and heat resistance is conventionally used, such as a polyimide film or a silicon rubber sheet. The sheet that is present can be used. In this embodiment, an insulating sheet in which three mica sheets are overlapped is used. However, the number of sheets is not limited, and if it is desired to provide more insulation, the sheet may be thickened, or a plurality of sheets may be added. It is also possible to integrate them together. Further, the thickness and shape may be appropriately selected according to the arrangement of the heater members, the power consumption of the planar heater, and the application.
[0027]
In the present embodiment, all the heater members are connected in series. However, if necessary, the heater members are connected in parallel, or lead wires are connected to the heat members 11, 12 and 13 to supply power independently. You can also
[0028]
Each heater member 11, 12 and 13 is sandwiched and fixed between insulating sheets 21, 22, 23 and 24 which are integrated by using a general bonding method in this field.
[0029]
The terminal portion 111 of the heater member 11 and the end portion 31 of the lead wire and the insulating sheet 21 in contact with the portion close to the end portion 31 of the lead wire are fastened by a fastener (not shown) through a part of the electrode portion sheet 41. Fixed mechanically.
[0030]
In addition, the bonding method between the sheets constituting the insulating sheet or the insulating sheet is appropriately determined according to the material of the sheet, for example, by applying and attaching a heat-resistant adhesive such as a silicon-based adhesive on the entire surface of the sheet. It is a choice.
[0031]
In this embodiment, the lead wire is fixed on the surface side of the insulating sheet 21, but in addition to fixing on the surface of the insulating sheet, the lead wire is sandwiched between two insulating sheets sandwiching the heat wire. In this state, it may be fixed to one or both of the two insulating sheets. Further, in this embodiment, when the lead wire is fixed, a part of the electrode portion sheet 41 is interposed, but the fastener inserted in the insulating sheet may be directly wound around the lead wire and fixed. At that time, if a mica sheet or the like is adhered and coated at least to the peripheral portion of the fastener, the portion becomes stronger. The electrode part sheet 41 is not particularly limited in size and material, but the same material as the insulating sheet is preferable. The shape and material of the fastener are not limited as long as the lead wire and the insulating sheet can be fixed. However, the fastener is preferably a strip or wire metal. In addition, a string shape, a ring shape, or the like may be used. In addition to a metal, a material such as ceramics, a heat-resistant resin, or a fiber may be used.
[0032]
In addition, the insulating coating 32 on the surface of the lead wire has a large friction or a protrusion is provided on the surface of the lead wire so that the lead wire fixed by the fastener does not shift in the line direction of the lead wire. May be.
[0033]
(Modification of Example 1)
The planar heater of Example 1 described above can be made cylindrical by bending. In that case, the form can be stabilized by inserting a planar heater into a metal cylinder.
[0034]
【The invention's effect】
The planar heater of the present invention has a plurality of laminated insulating sheets and a plurality of heater members sandwiched between the insulating sheets and stacked with a gap therebetween, thereby increasing the applied voltage. Can do. Furthermore, even when the applied voltage is increased, the current value is not limited, and the amount of heat generated per unit area can be increased.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a cross section of a planar heater according to an embodiment.
FIG. 2 is a plan view showing an example of the arrangement of heater members in the planar heater of the embodiment.
FIG. 3 is a view schematically showing a cross section of a conventional planar heater.
[Explanation of symbols]
11, 12, 13 ... Heat members 21, 22, 23, 24 ... Insulating sheets 31, 32 ... Lead wires

Claims (4)

A planar heater, comprising: a plurality of laminated insulating sheets; and a plurality of heater members sandwiched between the insulating sheets and stacked with a gap therebetween. The planar heater according to claim 1, wherein the plurality of heater members have terminal portions at both ends, and are connected in series and / or in parallel via the terminal portions. The terminal parts to be connected are arranged in the vicinity,
The planar heater according to claim 2, wherein the insulating sheet has a through hole that penetrates and connects the terminal portions in a vicinity of the terminal portion. The planar heater according to claim 1, wherein the planar heater is bent into a cylindrical shape.

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