JP2018101490A - Heater unit and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heater unit having excellent temperature rising characteristics.SOLUTION: Preferably, A heater unit has a layer configuration in which a metal electrode plate is provided on the upper and lower surfaces of a flat plate-like positive temperature coefficient ceramic element via a first adhesive layer, and a metal heat radiation plate is provided on the further outer side of the metal electrode plate via a second adhesive layer, and the second adhesive layer contains particulate insulating material in a dispersed state. In this case, a proportion of the insulating material in the second adhesive layer is 5 to 50% by weight, and the insulating material is glass beads having an average particle size of 30 to 100 μm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heater unit having excellent temperature rise characteristics, and more particularly, to a heater unit using a positive temperature coefficient (PTC) heater element as a heat source and a method for manufacturing the same.

Up to now, flat heaters using PTC heater elements having a self-temperature control function as a heat source have been used in many fields as constant temperature heaters and local heaters. As an in-vehicle heater, a heating element having an electrode surface, an electrode member that is in contact with the electrode surface and superimposed on the heating element, an insulating sheet that wraps the heating element and the electrode member, and an insulating sheet A hollow body that accommodates the heat generating element and the electrode member, a cylinder having a heat radiating surface through which heat from the heat generating element is conducted, and a heat radiating unit provided on the heat radiating surface of the cylinder including at least fins; What is provided is disclosed.
As shown in FIG. 2, such a conventional flat heater is composed of an electrode formed on the main surface of the PTC heater element 1 and a metal electrode plate 3 in order to insulate the PTC heater element 1 from the heater unit. 6 is bonded, and an insulating sheet 7 (for example, a polyimide sheet manufactured by Toray DuPont Co., Ltd., trade name: Kapton (registered trademark)) is wound around the insulating sheet 7 to form a rectangular pipe shape for conducting heat. Although it has a structure in which the metal 8 is press-contacted, such a structure causes a thermal resistance and has a problem in the temperature rise characteristics of the heater.

Japanese Patent No. 4455473

An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a positive temperature coefficient heater unit (PTC heater unit) having excellent temperature rise characteristics. Another object of the present invention is to provide a method for manufacturing the heater unit.
As a result of various studies, the present inventor has adhered the electrode formed on the main surface of the PTC heater element and the metal electrode plate with an adhesive, and in addition, an adhesive layer in which a particulate insulating material is further mixed and dispersed. The present invention has been completed by finding that by adhering a heat sink, insulation from the PTC heater element can be secured and heat generated by the PTC heater element can be transmitted to the heated object more quickly and uniformly.

  In the heater unit of the present invention capable of solving the above-described problems, a metal electrode plate is provided on the upper surface and the lower surface of a flat PTC heater element via a first adhesive layer, respectively, and further outside the metal electrode plate. It has a layer structure in which a metal heat dissipation plate is provided via a second adhesive layer, and the second adhesive layer includes a particulate insulating material in a dispersed state.

  In the heater unit having the above-described characteristics, the ratio of the insulating material in the second adhesive layer is 5 to 50% by weight.

  In the heater unit having the above characteristics, the present invention is characterized in that the insulating material is glass beads having an average particle diameter of 30 to 100 μm.

Furthermore, the present invention is a method for manufacturing a heater unit having the above-described characteristics, and the manufacturing method includes the following steps:
A step of applying an adhesive on the upper and lower surfaces of a flat plate-like positive temperature coefficient ceramic element and attaching a metal electrode plate; and an adhesive in which a particulate insulating material is mixed and dispersed; After applying to the surface of an electrode plate, the process of sticking a metal heat sink is characterized.

  According to the present invention, it is possible to obtain a heater unit having superior temperature rise characteristics than the conventional example. This property can minimize the thermal resistance by adhering the metal heat sink to the surface of the metal electrode plate adhered to the PTC heater element by using an adhesive layer containing a particulate insulating material. .

It is a figure which shows the structure which concerns on one embodiment of the heater unit of this invention. It is a figure which shows the structure of the conventional heater unit. It is the graph which compared the temperature rising characteristic about the heater unit of this invention produced in the Example, and the conventional product.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, in the heater unit of the present invention, the metal electrode plate 3 is provided on the upper surface and the lower surface (both electrode surfaces) of the flat PTC heater element 1 via the first adhesive layer 2. A metal heat radiating plate 5 is provided on the outer side of the metal electrode plate 3 with a second adhesive layer 4 interposed therebetween.

The flat PTC heater element 1 according to the present invention is a ceramic element having a positive temperature characteristic. This element has a resistance that increases abruptly when the temperature reaches a Curie point or higher, and suppresses the energized current. It has a function to limit the above temperature rise. With the above function of the PTC heater element 1, the temperature control circuit and the overheat prevention circuit can be omitted, and the power consumption can be reduced.
The first adhesive layer 2 provided on the upper and lower surfaces of the PTC heater element 1 is preferably formed using a silicon-based adhesive from the viewpoint of heat resistance, conductivity, and thermal conductivity. The plate 3 is a metal plate made of aluminum or stainless steel, and the thickness of the metal electrode plate 3 is preferably 0.2 to 0.5 mm.

  The second adhesive layer 4 (preferably having a thickness of 50 to 500 μm) has a ratio of 5 to 50% by weight, preferably 15 to 30% by weight, in a state where the particulate insulating material is dispersed in the adhesive. Included as a percentage. The adhesive used for forming the second adhesive layer 4 in the present invention is preferably a silicon-based adhesive from the viewpoint of heat resistance, conductivity and thermal conductivity, and the particulate insulating material is an organic insulating material. However, spherical glass beads having an average particle diameter of 30 to 100 μm are preferable, and glass beads having an average particle diameter of 40 to 60 μm are particularly preferable. As such spherical glass beads, commercially available products can be widely used, and the above average particle diameter is measured by an image analysis method using an optical microscope (JIS Z8827-1).

  Moreover, as the metal heat sink 5 adhered to the outer surface of the metal electrode plate 3 by the second adhesive layer 4, for example, one made of a metal having excellent thermal conductivity such as aluminum or stainless steel is generally used. There is a preferable thickness of 0.2 to 0.5 mm. In the case of the heater unit of the present invention, since the particulate insulating material is dispersed in the second adhesive layer 4, it is insulated from the metal electrode plate 3 without using an insulating sheet. A metal heat sink 5 can be provided. Moreover, in order to improve heat dissipation, the thickness of the metal heat sink 5 can also be reduced to a minimum (preferably 0.5 mm or less).

The manufacturing method of the present invention for manufacturing the heater unit includes a step of applying an adhesive to the upper and lower surfaces of a flat PTC ceramic element and attaching a metal electrode plate, 50% by weight mixed and dispersed adhesive is prepared, and after the adhesive is applied to the surface of the metal electrode plate, a metal heat dissipating plate is attached. The metal electrode plates are formed on both main surfaces of the PTC ceramic element. As the adhesive used in the first step of attaching, a silicon-based adhesive is preferable, and as the adhesive layer material used in the second step of attaching the metal heat sink, organic or inorganic particulate insulation is used. A silicon-based adhesive in which the material is uniformly dispersed is preferable.
At this time, it is preferable to mix and disperse the glass beads at a ratio of 5 to 50% by weight in the adhesive for bonding the outer metal heat sink. If it is less than 5% by weight, it is difficult to maintain insulation, and if it exceeds 50% by weight, the thermal conductivity is hindered. Therefore, it occupies the second adhesive layer 4 from the viewpoint of achieving both insulation and thermal conductivity. The proportion of glass beads (insulating material) is preferably 5 to 10% by weight. Further, it is preferable to use an adhesive layer material in which glass beads having an average particle size of 30 to 100 μm are mixed and dispersed. A heater unit to which a metal heat radiating plate is attached using such an adhesive layer material has excellent temperature rise characteristics, that is, rapid heat that reaches a predetermined temperature in a short time.
Hereinafter, the present invention will be specifically described with reference to production examples of the heater unit of the present invention, but the present invention is not limited thereto.

As an example of the present invention, a commercially available silicon-based adhesive was applied to both main surfaces of a PTC element (15 mm × 25 mm, thickness 2 mm) having a Curie point of 250 ° C. with a coating thickness of about 50 μm, and a metal electrode plate (material: aluminum And a thickness of 0.2 mm). Furthermore, commercially available glass beads having an average particle diameter of 50 μm are mixed at a rate of 20% by weight (ratio of glass beads contained in the adhesive layer material) with respect to the resin solid content of the silicon adhesive (same as above). The dispersed dispersion was applied at a coating thickness of about 100 μm, and a metal heat radiating plate (material: aluminum, thickness 0.2 mm) was attached to the coated surface. The laminated body thus obtained was heated at a temperature of 150 ° C. for 1 hour to thermally cure the silicon-based adhesive, thereby producing the PTC heater unit of the present invention having the layer configuration shown in FIG. .
On the other hand, as a conventional example, the same commercially available silicon-based adhesive as that used in the above-described example of the present invention is applied to both main surfaces of the same PTC element used in the above-described example of the present invention, and the thickness is set to 0. A 2 mm metal electrode plate was attached. The laminated body thus obtained is insulated by winding an insulating sheet (a Kapton (registered trademark) film having a thickness of 50 μm), and further covered with a metal square tube, and pressure is applied to the square tube to insulate the above-mentioned insulation. A PTC heater unit having the configuration shown in FIG.

FIG. 3 shows the temperature rise characteristics of the present invention example and the conventional example obtained above.
As shown in FIG. 3, even when the same PTC element is used, there is a large difference between the present invention example and the conventional example. In the present invention example, the temperature reaches a predetermined temperature in a short time, and this temperature is Maintained constant. Further, in the case of the present invention example, a metal heat sink insulated from the electrode plate can be provided without using an insulating sheet such as Kapton (registered trademark) film. In order to improve heat dissipation, it can be made as thin as necessary.
On the other hand, in the case of the conventional example, pressure is applied to the square pipe and pressed against the insulating sheet to form a metal heat radiating plate. Therefore, as in the present invention example, the metal heat radiation constituting the square pipe is used. The thickness of the plate cannot be reduced to 1.0 mm or less. If the thickness is reduced below that, the rigidity of the square pipe is lowered, and the shape of the heater unit cannot be maintained. Furthermore, in this conventional example, there is a risk that cracks may occur in the ceramic PTC element due to the pressure applied when the square pipe and the insulating sheet are pressed, and the insulating sheet is damaged during the pressing. There was also a possibility that insulation could not be maintained.
As can be seen from the comparative tests in the above examples, the present invention can solve the problems in the conventional example, and in the present invention, the metal heat dissipation plate and the metal electrode plate are minimized and the thermal resistance is minimized. Therefore, the structure of the PTC heater unit, which requires quick heat, is superior to the conventional structure.

  The heater unit of the present invention has an excellent temperature rise characteristic that reaches a predetermined temperature in a short time and keeps the temperature. It can be used for a wide range of heaters.

1 PTC ceramic element (positive temperature coefficient ceramic element)
2 First adhesive layer 3 Metal electrode plate 4 Second adhesive layer (layer containing particulate insulating material)
5 Metal heat sink 6 Adhesive layer 7 Insulating sheet 8 Square pipe-shaped metal

Claims (4)

  A metal electrode plate is provided on each of the upper surface and the lower surface of the flat positive temperature coefficient ceramic element via a first adhesive layer, and a metal heat sink is provided on the outer side of the metal electrode plate via a second adhesive layer. The heater unit is characterized by having a layered structure, and the second adhesive layer includes a particulate insulating material in a dispersed state.   The heater unit according to claim 1, wherein a ratio of the insulating material in the second adhesive layer is 5 to 50% by weight.   The heater unit according to claim 1, wherein the insulating material is glass beads having an average particle diameter of 30 to 100 μm. A method for producing a heater unit, the production method comprising the following steps:
A step of applying an adhesive on the upper and lower surfaces of a flat plate-like positive temperature coefficient ceramic element and attaching a metal electrode plate; and an adhesive in which a particulate insulating material is mixed and dispersed; A method for manufacturing a heater unit, comprising: applying a metal heat radiating plate after applying to the surface of an electrode plate.

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