JP2000133425A - Flexible heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible heating element capable of enhancing durability and preventing a possibility of a fire by preventing generation of excessive local heating due to bending and local pressure, and further capable of securing stability of feeding performance, leading to improvement of product yields. SOLUTION: Supporting sheets 1 such as prepreg are integrally formed by pressing and heating with a felt or cloth heating sheet 2 interposed therebetween, thus the thickness of a flexible heating element is almost the same as the supporting sheets themselves and is very thin. A band-shaped electrode 3 is pressed and heated together with the heating sheet 2, and the band-shaped electrode 3 is integrally formed with the supporting sheet 1, thus an electrical connection between the band-shaped electrode 3 and the heating sheet 2 is secured. The supporting sheet 1 protects the flexible heating element from bending and local pressure, and thus generation of excessive local heating can be prevented and the durability can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet heating element,
The present invention relates to a flexible heating element having flexibility or flexibility.

[0002]

2. Description of the Related Art As a planar heating element having flexibility or flexibility, a heating element in which a conductive powder such as carbon is dispersed and solidified in a resin such as ethylene tetrafluoride is known. When such a planar heating element is bent or deformed by applying a local pressure, the distance between the conductive powders in the bent portion or the pressure deformed portion becomes small, and the resistance value becomes low. Due to the flow of electric current, overheating was locally caused, shortening the life of the product and causing a fire.

Further, in the conventional electrical and mechanical connection between the sheet heating element and the electrode, a metal foil such as copper is used as an electrode, and the metal foil is sewn with a metal wire such as a copper wire. It was connected to the heating element by riveting, riveting, or bolting through a holding plate. However, in connection by sewing or riveting, when viewed electrically, they are only in point contact with each other. In addition, electrical contact failures occur due to the inefficient use, and the connection by bolting is easy to cause the local overheating described above. Therefore, the attachment of the electrodes to the conventional planar heating element has an unstable power supply performance, which has been a factor that significantly reduces the product yield.

[0004]

DISCLOSURE OF THE INVENTION The present invention improves the durability by reliably preventing the occurrence of local overheating even when bending or applying a local pressure, and improves the durability of a fire. Provide a flexible heating element that can avoid dangers and ensure stable power supply performance by ensuring electrical and mechanical connections, thereby improving product yield What you want to do.

[0005]

The flexible heating element according to the present invention comprises a support sheet made of resin or prepreg laminated on each other, and a heat generation sheet disposed between the support sheets. The heat generating sheet is formed in a felt or cloth shape using a fibrous heat generating material that generates heat when energized, and on at least one surface thereof is formed of at least two fibrous conductive materials having good conductivity. The strip-shaped electrodes are arranged at predetermined intervals from each other. Each support sheet is integrated with each other by holding the band-shaped electrode in a predetermined position and pressurizing and heating so as to include the heat generating sheet.

[0006] The flexible heating element according to the present invention also includes:
It is also possible to comprise at least three support sheets made of a resin or a prepreg laminated on each other and at least one heat generating sheet disposed between two support sheets adjacent to each other. Each heating sheet is formed in a felt or cloth shape using a fibrous heating material that generates heat when energized, and is formed on one surface of each heating sheet with a fibrous conductive material having good conductivity. In addition, at least two strip-shaped electrodes are arranged at predetermined intervals from each other. The support sheets are integrated with each other by holding the band-shaped electrodes in a predetermined position and pressurizing and heating them so as to enclose the heat-generating member.

[0007] Since the flexible heating element is integrated with each other by press-heating and forming a supporting sheet with a heating sheet interposed therebetween, its thickness is only about the same as the thickness of the supporting sheet. It has the advantage that it can be formed thinner. Since the strip electrode is pressed by the support sheet and integrated with the heat generation sheet, electrical connection between the strip electrode and the heat generation sheet can be reliably performed.
The heat generating sheet is protected by the supporting sheet against bending and local pressurization, so that local overheating can be prevented and durability can be improved.

[0008] The flexible heating element according to the present invention further comprises:
The band-shaped electrodes stacked via the support sheet can be electrically connected to each other by through-hole processing. Further, at least three band-shaped electrodes can be arranged so that the band-shaped electrodes adjacent to each other have a predetermined spacing, and the spacing can be changed according to a required heat generation amount distribution. it can. Furthermore, the strip electrodes can be provided in a circular shape or in a closed curved shape.

In the flexible heating element according to the present invention, the supporting sheet is integrated with a metal plate such as an enamel plate, an aluminum plate, a stainless steel plate or a suitable heat-resistant structural member such as a resin or ceramic. It can also be formed into various shapes by irregular or three-dimensional molding.

Further, the flexible heating element according to the present invention can be provided with an opening in the heating sheet according to a required heat generation distribution, or can be formed with an opening for inserting a structural member. It is also possible to use a plurality of heat generating sheets stacked so as to generate the heat generation amount.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 A flexible heating element according to an embodiment of the present invention, as shown in FIGS. 1 and 2, is provided between two mutually stacked support sheets 1, 1 and between the support sheets 1, 1. And a heat generating sheet 2 to be formed. On one surface of the heat generating sheet 2, a pair of strip-shaped electrodes 3, 3 are arranged at a predetermined interval D from each other. At one end of each strip electrode 3, a terminal 4 for connection to an external power supply (not shown) for supplying power to the heat generating sheet 2 is provided.

The support sheet 1 is a conventional prepreg sheet used for a flexible printed circuit board. Generally, an epoxy resin sheet using glass fiber as a reinforcing material is used. However, other resin sheets can also be used as long as they can have heat resistance at the heating temperature of the present flexible heating element.

The heat generating sheet 2 is formed in a felt or cloth shape by using a fibrous heat generating material that generates heat when energized. The fibrous heat-generating material forming the heat-generating sheet 2 has a constant resistance value and has a fibrous beard on at least its outer surface so that it can be entangled with the strip-shaped electrode 3 described later. Any material can be used as long as it can withstand the temperature at which the flexible heating element generates heat. Preferable examples of the fibrous heating material include carbon felt which is an application form of the pitch-based carbon fiber “Donacarb. S (trade name)” developed by Osaka Gas Co., Ltd., and metal such as titanium and titanium carbide. A powder obtained by adhering and mixing powder into glass fiber can be used.

The strip electrode 3 is formed by forming a fibrous conductive material into a strip shape. The fibrous conductive material forming the strip electrode 3 has good conductivity, has a fibrous whisker on at least its outer surface, and can be entangled with the fibrous heat generating material of the heat generating sheet 2, Any material that can withstand at least the heat generation temperature of the heat generation sheet 2 can be used. Preferable examples of the fibrous conductive material include the above-mentioned pitch-based carbon fiber “Donnacarbo S”
Carbon paper, which is an applicable form of, and "CNP nickel mat (trade name)" developed by Osaka Gas Co., Ltd., in which pitch-based carbon fiber is plated with nickel.

The flexible heating element according to the present invention is manufactured by integrating the laminated support sheets 1 and 1 with each other using a pressurizing and heating molding means (not shown). At this time, the joining surfaces of the heat generating sheet 2 and the band-shaped electrode 3 are pressed and heated in a state of being entangled with each other, so that the electrical connection between the two can be reliably maintained. Heating sheet 2
Is compressed and held by the support sheets 1 and 1, and the thickness of the flexible heating element is formed substantially by the thickness of the support sheet 1.

The integral molding using the pressurizing and heating molding means means that the support sheet 1 can be formed into any shaped article or three-dimensional molded article with any shape. Examples of the irregularly shaped article and the three-dimensional molded article are shown in FIGS. 3 and 4, respectively.

In the case of the modification shown in FIG. 3, one of the strip electrodes 3 is provided in a circular shape or a closed curved shape along the outer peripheral edge of the heat generating sheet 2, and the other strip electrode 3 is formed of the one strip electrode. Disc-shaped at a position separated by a distance D from 3
It is provided in a circular shape or a closed curved shape. on the other hand,
In the case of the modification shown in FIG. 4, the separation distance D between the strip electrodes 3, 3 is not the linear distance between the strip electrodes 3, but the length along the heating sheet 2 located between the strip electrodes 3, 3. Corresponds to L.

The flexible heating element of the present invention formed as described above supplies power to the heating sheet 2 via the band-shaped electrode 3 by connecting the terminal 4 to an external power supply.
When energized, the heat generating sheet 2 generates heat by its internal resistance. Since the heating sheet 2 and the strip electrodes 3 are covered by the support sheet 1, they are electrically insulated reliably, and since they are integrated by the support sheet 1, they can be deformed by bending or local pressure. However, the resistance value is not lowered due to the partial density change of the heat generation sheet 2 so that an overcurrent does not flow or a local overheating is performed, and the danger of fire occurrence can be prevented and the durability can be improved. it can.

[0019]

Embodiment 2 FIG. 5 is a view showing a flexible heating element according to another embodiment of the present invention.
4) and heat generating sheets 2 disposed between two adjacent support sheets 1, 1, respectively. The configuration is the same as that of the above-described embodiment except that a pair of band-shaped electrodes 3 and 3 are provided.

A strip electrode 3 provided on each heating sheet 2
In the same manner as in the previous embodiment, a terminal 4 may be provided at one end thereof, but as shown in FIG. 6, a through-hole processing 5 passing through the laminated strip-shaped electrodes 3, that is, a through-hole is formed, By covering or filling the inside of the through-hole with a conductive member, the stacked strip electrodes 3 are electrically connected, and one of the stacked strip electrodes 3 is connected to a terminal 4.
Is preferably provided. This makes it possible to avoid complications in making and wiring work by arranging terminals on each strip-shaped electrode 3 and performing wiring work for connecting each terminal to an external power supply.

The flexible heating element in this embodiment is provided with the heating sheet 2 in a multilayer structure.
As compared with the heating value of the flexible heating element of the above-described embodiment, the heating value can be increased by the number of layers.

Although the flexible heating element in each of the above-described embodiments has been described as a single component, as shown in FIG. 7, when forming the support sheet 1 under pressure and heat, the components of the flexible heating element are heated by tableware. A flexible heating element integrated with a product can be created by placing the product on a structural member S such as a shelf plate of a shelf and performing pressure and heat molding. As the structural member S, a metal plate such as an enamel plate, an aluminum plate or a stainless steel plate, or a suitable heat-resistant member such as a resin or ceramic can be used.

Further, the heat generating sheet 2 in each of the above-described embodiments and modifications is illustrated and described so that only one heat generating sheet 2 is used between the support sheets 1 and 1. However, as shown in FIG. In this case, two (2) heat-generating sheets 2 are directly laminated on each other and used, so that the amount of heat generated can be increased by the number of laminations as compared with a single case. Since the heat generating sheets 2 are integrated with each other at the time of pressurizing and heating, they can substantially function as one heat generating sheet. This means that flexible heating elements with different heating values can be created by preparing the same quality heating sheet material, reducing material costs and simplifying inventory management. Etc. can be secured.

It is preferable that the strip-shaped electrode 3 in this modified example is disposed between the stacked heat generating sheets 2 and 2. Since the strip-shaped electrodes 3 disposed between the heat-generating sheets 2 and 2 are in direct contact with and integrated with the respective heat-generating sheets 2, the electrical connection between the heat-generating sheet 2 and the band-shaped electrodes 3 can be further ensured. it can.

In each of the above-described embodiments and modifications, the strip electrodes 3 are illustrated and described as using two strip electrodes 3 for one heat generating sheet 2, but as shown in FIG. If the interval between the two strip electrodes 3 is too wide, at least one strip electrode 3 is placed between the two strip electrodes 3.
Is preferably formed so that the interval between two adjacent strip electrodes 3 is a predetermined interval D. At this time, every other strip electrode 3 is electrically connected (when the supply power is DC or two-phase AC). On the other hand, when the heat generating sheet 2 is in an irregular shape, as shown in FIG. 10, the shape and arrangement position of each strip electrode 3 should be selected so that the interval between each strip electrode 3 becomes a predetermined spacing D. It is.

On the other hand, the flexible heating element in each of the above-described embodiments and modifications has been shown and described so as to generate heat uniformly over the entire surface. However, the dimensions and / or arrangement of the heating sheet 2 and / or the strip-shaped electrode 3 have been described. By appropriately selecting the installation positional relationship, a flexible heating element having a region where the amount of heat generation is partially large or a region where the amount of heat generation is partially small can be created.

When the heat generation sheet 2 responds to this partial change in the heat generation amount, as shown in FIG. 11, an opening 6 is formed in a region R1 of the heat generation sheet 2 where the required heat generation amount is small. The opening 6 can be formed by perforating the heat-generating sheet 2 before press-heating and forming the support sheet 1. However, the amount of heat generated is reduced due to the deformation of the opening 6 during press-heating and forming. In order to prevent the amount from being changed, it is preferable to perform a punching process after the pressing and heating molding. However, when the boring process is performed after the pressure heating molding, the heat generating sheet 2 is exposed on the inner peripheral surface of the opening 6. Therefore, in order to prevent other components from coming into contact with the exposed heat generating sheet 2 to cause an electric leakage or the like, an exposure preventing means, for example, a means of covering with an insulating material should be taken.

Here, the fact that the opening 6 can be provided in the flexible heating element means that the possibility of changing the shape of the flexible heating element in accordance with the structure to which the flexible heating element is mounted is increased. For example, in the United States and the like, since a general drive-through cash dispenser is installed outdoors, there is a risk of freezing during a severe winter, and it is necessary to heat the input key. In such a case, as shown in FIG. 12, by forming the opening 6 as a hole through which the input key K is inserted, a flexible heating element that can be attached to the key panel can be created. Can be prevented from malfunctioning due to freezing. At this time, the arrangement position of the opening 6 is selected so that the flexible heating element generates heat uniformly as a whole.

In the case where a partial change in the calorific value is dealt with by the strip-shaped electrodes 3, the distance D1 between the pair of strip-shaped electrodes 3 in the region R1 where the required calorific value is small is relatively large, while the gap is required. This can be achieved by making the separation distance D2 between the pair of strip electrodes 3 relatively small in the region R2 where the heat generation amount is large.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a flexible heating element according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view taken along line II-II of FIG.

FIG. 3 is a view similar to FIG. 1, showing a modification of the flexible heating element of the present invention.

FIG. 4 is a view similar to FIG. 2, showing another modification of the flexible heating element of the present invention.

FIG. 5 is a view similar to FIG. 2 showing a flexible heating element according to another embodiment of the present invention.

FIG. 6 is a partial cross-sectional view for explaining through-hole processing used in the present invention.

FIG. 7 is a schematic sectional view showing another modification of the flexible heating element of the present invention.

FIG. 8 is a schematic sectional view showing another modification of the flexible heating element of the present invention.

FIG. 9 is a schematic plan view showing another modified example of the flexible heating element of the present invention.

FIG. 10 is a schematic plan view showing another modification of the flexible heating element of the present invention.

FIG. 11 is a schematic plan view showing another modification of the flexible heating element of the present invention.

FIG. 12 is a schematic plan view showing another modified example of the flexible heating element of the present invention.

FIG. 13 is a schematic plan view showing another modification of the flexible heating element of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support sheet 2 Heating sheet 3 Strip electrode 4 Terminal 5 Through hole processing 6 Opening D Separation interval (between strip electrodes) S Structural member

Continued on the front page F term (reference) 3K034 AA02 AA05 AA06 AA08 AA09 AA15 BA08 BA10 BA13 BA20 BB08 BB10 BB16 BB17 BC09 BC17 BC23 CA06 CA13 CA17 CA29 CA32 CA39 FA02 FA12 FA16 FA17 FA39 GA02 GA04 JA09

Claims (10)

[Claims] 1. A heating device comprising: a support sheet made of a resin or a prepreg laminated on each other; and a heat generation sheet disposed between the support sheets, wherein the heat generation sheet is made of a fibrous heat generation material that generates heat when energized. At least two strip-shaped electrodes formed in a felt-like or cloth-like shape and made of a fibrous conductive material having good conductivity are arranged on one surface thereof with a predetermined spacing therebetween. The flexible heating element is provided, wherein the support sheets are integrated with each other by holding the band-shaped electrode in a predetermined position and pressurizing and heating to enclose the heating sheet. 2. A semiconductor device comprising: at least three support sheets made of a resin or a prepreg laminated on each other; and at least one heat generation sheet disposed between two support sheets adjacent to each other. Each of the heat generating sheets is formed in a felt shape or a cloth shape using a fibrous heat generating material that generates heat when energized, and is formed on one surface of each of the heat generating sheets by a fibrous conductive material having good conductivity. The at least two band-shaped electrodes are disposed at predetermined intervals from each other, and the support sheet is formed by pressing and heating so as to hold the band-shaped electrodes at predetermined positions and enclose a heating member. A flexible heating element characterized by being integrated with each other by: 3. The flexible heating element according to claim 2, wherein the band-shaped electrodes provided on each of the heat-generating sheets are connected between the corresponding band-shaped electrodes by through-hole processing. 4. At least three strip-shaped electrodes are provided on one surface of the heat-generating sheet, and each strip-shaped electrode is arranged such that a gap between adjacent strip-shaped electrodes is a predetermined spacing. The flexible heating element according to claim 2, wherein: 5. The flexible heating element according to claim 1, wherein the spacing between the strip electrodes is arranged so as to change in accordance with a required calorific value distribution. . 6. The flexible heating element according to claim 1, wherein the strip electrode has a circular shape or a closed curved shape. 7. The support sheet is integrated with a metal plate such as an enamel plate, an aluminum plate or a stainless steel plate or a suitable heat-resistant structural member such as a resin or ceramic. The flexible heating element according to any one of claims 1 to 6. 8. The flexible heating element according to claim 1, wherein the support sheet is formed in an irregular shape or a three-dimensional shape. 9. The heat generating sheet according to claim 1, wherein an opening for inserting a structural member is provided according to a required heat generation amount distribution. 3. The flexible heating element according to item 1. 10. The heat generating sheet according to claim 1, wherein a plurality of heat generating sheets are laminated and used according to a required heat generation amount.
The flexible heating element according to any one of claims 9 to 9.