JPH0513153A - Positive characteristic thermistor heating device - Google Patents

Abstract

PURPOSE:To ensure a satisfactory insulated state of a metal radiator without loosing radiating characteristic and pressure by forming an anode oxidized film layer on the exposed surface of a metal radiator forming a circuit for supplying a current to a heating element. CONSTITUTION:A pair of metal radiators formed containing a corrugate fin 141 are adhered and mounted to both surface parts of a heating element 11 by a positive characteristic thermistor disposed in a plate form, and an anode oxidized film layer 17 is formed on the surface on which the metal radiator is exposed. According to this constitution, since all the ventilating parts of the metal radiators formed containing the corrugate fin 141 are insulated by the insulating film by the anode oxidized film layer 17, the insulating property of the metal radiators is ensured, and no pressure loss is caused at the time of passing air, and heat conductivity can be satisfactorily ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, an indoor heater,
The present invention relates to a positive temperature coefficient thermistor heat generating device which is used in clothes dryers, futon dryers, etc. and has excellent safety, quick heatability and excellent reliability.

[0002]

2. Description of the Related Art A heat generating device using a positive temperature coefficient thermistor is
Since it is excellent in safety and reliability, it is applied in various fields. Such a PTC thermistor heat generating device has a structure in which a conductive metal plate is provided on both sides of a heating element constituted by a PTC thermistor formed in a plate shape.
The angle member is set to be adhered, a corrugated fin made of a metal plate is attached to the outside of the angle member, and a second angle member made of a conductive metal plate is attached so as to be supported by the corrugated fin. Is configured.

In the heat generating device having such a structure,
Connect the second angle member set on the outside to the power supply,
Via the corrugated fin and the first angle member,
Power is supplied to the heating element.

In such a heat generating device, the first and second angle members constituting the circuit for supplying power to the heat generating element, and the metal heat radiating member constituted by the corrugated fins are connected to the air flow as the heat exchange medium. Exposed to touch. Therefore, if conductive foreign matter or condensed water comes to adhere to the metal radiator, the power supply circuit may be short-circuited.

In order to deal with such a problem, the surface of the metal radiator consisting of corrugated fins and angle members is coated with Teflon or silicon resin,
It is considered that the insulating layer is formed on the surface. However, if such an insulating layer is formed on the surface of the metal radiator, it becomes difficult to paint the edge portion of the metal radiator, and the problem that the heat dissipation property is deteriorated as the pressure loss increases Occurs.

Further, electrode plates connected to a power source are set oppositely on both sides of the heating element, and an insulating layer is formed on the outer side surface of the electrode plate, and an angle member and corrugated fins are formed through the insulating layer. Then, it is also possible to attach a metal radiator. However, in such a configuration, the heat of the heating element is conducted to the metal radiator through the insulating layer, the heat radiation performance is deteriorated, and the cost is disadvantageous.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has an advantage in that it can be effectively used in a heater, a drier or the like without causing heat dissipation characteristics and pressure loss. At the same time, an object of the present invention is to provide a highly reliable positive temperature coefficient thermistor heating device in which a good insulating state is secured including the edge portion of the metal radiator.

[0008]

A positive temperature coefficient thermistor heat generating device according to the present invention sets a pair of metal heat radiators in contact with each other so as to sandwich a heat generating element constituted by a positive temperature coefficient thermistor, and through the pair of metal heat radiators. Power is supplied to the heating element. Then, an anodic oxide film layer is formed on the exposed surface of each of the pair of metal radiators.

[0009]

In the PTC thermistor heating device having such a structure, electric power is supplied to the heating element through the pair of metal radiators, the heating element generates heat, and the heat is efficiently transmitted to each of the pair of metal radiators. Be transmitted. In this case, since the anodic oxide film layer formed on the surface of the metal radiator is an insulating layer, even if conductive foreign matter or condensed water adheres to the surface of the metal radiator, the anodic oxide film is Since even the edge portion is surely formed on the metal radiator, safety is ensured without electrical short circuit, and the anodic oxide film is formed to have a uniform thickness. In addition, the dimensions of the metal radiator are not changed, pressure loss does not occur when the heat exchange medium such as air flows, and the heat exchange characteristics are set stably.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows its cross-sectional structure, which includes a heating element 11 composed of a plate-shaped positive temperature coefficient thermistor,
First angle plates 121 and 122 made of a conductive metal plate are joined to both surfaces of the heating element 11.

The first angle plates 121 and 122 are made of a conductive metal plate so as to be opposed to each other with a space therebetween.
The corrugated fins 141 and 142 formed by corrugating a metal plate are interposed between the angle plates 121 and 131 and between the angle plates 122 and 132, respectively.

The angle plates 121, 131 and 122
And 132 are corrugated fins 141 and 142, respectively.
So that they are integrally joined together by brazing to each other, and the first and second sides are respectively provided on both sides of the heating element 11.
The metal radiators 151 and 152 are joined together.

Here, the heating element 11 is constructed by arranging a plurality of plate-shaped single elements side by side, and the heating element 11 formed by arranging the plurality of single element elements is sandwiched on both sides, for example, an aluminum plate. First configured by
The angle plates 121 and 122 are joined using an adhesive. Similarly, the second angle plates 131 and 132 are also aluminum plates, and the second angle plates 131 and 132 act as electrodes for supplying a power source. Between the power 16
Are connected.

Corrugated fins 141 and 142
Is formed by bending an aluminum plate having a thickness of 200 μm, and the corrugated fins 141 and 142 are the first
And brazed to the second angle plates 121, 122 and 131, 132.

When manufacturing such a heat generating device, first, the first and second angle plates 121 and 122, and the second
The corrugated fins 141 and 142 are sandwiched between the angle plates 131 and 132, respectively, and the corrugated fins 141 and 142 are integrally joined by brazing to assemble the first and second metal radiators 151 and 152.

The metal radiators 151 and 152 thus assembled are subjected to an etching treatment for 10 seconds at 70 ° C. in an aqueous solution of 5% NaOH and 2% NaF, and then washed with water for 5 minutes. _{H 2 C 2 O 4 · 2H} 2 O:
11 g / l, Conc H ₂ SO ₄ : 106 g / l, Al
³⁺ 3.5g / l, D _A : 2A / dm ² , 20 at 25V
Anodize for a minute. Then, after ultrasonic cleaning with running water for 10 minutes, it is dried at 150 ° C. for 30 minutes.

The anodic oxidation treatment is carried out in this way, and the insulating anodic oxide film layer 17 is formed on the exposed surface portion as shown in FIG. First angle plate 12 that comes into contact with 11
The contact surfaces of 1 and 122 with the heating element 11 are mechanically polished to expose their aluminum surfaces. Further, the terminal portions of the second angle members 131 and 132 connected to the power source 16 are also mechanically polished to remove the insulating anodic oxide film layer.

On the polishing surfaces of the first and second metal radiators 151 and 152 thus configured, which come into contact with the heating elements 11, the silicon adhesive 18 (excellent in heat resistance and thermal conductivity) is formed. 50 kg / cm ² with the heating element 11 that is set by arranging a plurality of element units side by side Is applied, and heat treatment is performed at 250 ° C. for 30 minutes to bond and fix.

In this case, a base electrode layer 20 is formed on both surfaces of the heating element 11 which is formed by arranging a plurality of element units side by side, and the surface electrode layer is formed on the surface of the base electrode layer 20. 21 are to be formed. In this case, on the surface of the surface electrode layer 21, a large number of irregularities are formed as shown in the enlarged view of the figure, and the adhesive 18 pressed by a large pressure is applied to the concave portion of the surface electrode layer 21. Get in.
Therefore, the adhesive 18 firmly adheres the first angle plates 121 and 122 of the metal radiators 151 and 152 to the surface electrode layer 21, and at the convex portion of the surface electrode layer 21, both of them are electrically connected. Will be connected.

Further, a silicone adhesive is applied to the peripheral portion of the side surface of the heating element 11 to form a sealing layer 19, and the heating element 11
Further, the side surfaces of the first and second metal radiators 151 and 152 are insulated.

In the heat generating device having such a structure,
The ventilation parts of the metal radiators 151 and 152 including the corrugated fins 141 and 142 are all anodic oxide film layers 17.
It is insulated by the insulating film. Therefore, for example, even if conductive foreign matter or condensed water adheres to the metal radiators 151 and 152, an electrical short circuit does not occur, and stability and reliability are reliably ensured.

Further, the metal radiators 151 and 152 made of aluminum or its alloy, which are easily corroded,
No direct exposure to corrosive atmosphere. Therefore, even when it is installed as a heating device in, for example, a toilet, it is not exposed to ammonia gas and the problem of corrosion does not occur.

Further, unlike the resin coating, the anodic oxide film layer 17 formed on the surfaces of the metal heat dissipating members 151 and 152 has almost no dimensional change. Therefore, the heater performance is not affected by the pressure loss of the heat exchange medium such as the circulating air or the increase of the thermal conductivity.

The thickness of the alumite layer formed by the anodic oxide film layer 17 thus formed is uniform and has a large adhesive strength. There is no need to worry about the decrease in thickness or the decrease in reliability due to peeling of the coating.

FIG. 3 shows another embodiment in which the structures of the first and second metal heat radiators 151 and 152 are changed, and the fins constituting the metal heat radiators 151 and 152, respectively.
Each of 211 and 212 is formed by folding an aluminum plate into a shape of an isosceles triangle in cross section, and angle plates 221 and 222 are brazed to one surface of each aluminum plate to be integrated. Then, the other surface is bonded to the surface of the heating element 11.

This heating device will be described according to the manufacturing process. First, the aluminum plates are folded back to form the fins 211 and 212 as shown in the figure, and the angle plates 221 are respectively formed on one side of one side of the triangle. First and second integrated brazed 222
Assemble the metal heat sinks 151 and 152 in. After that, the first and second metal radiators 151 and 152 are anodized in the same manner as in the previous embodiment, and the surfaces of the fins 211 and 212 and the angle plates 221 and 222 are enlarged as shown in FIG. An anodic oxide film layer 17 is formed.

The surfaces of the first and second metal radiators 211 and 212 thus assembled, which are in contact with the heating element 11, and the anodic oxide film layer of the electrode portion to which the power source 16 is connected are mechanically polished. Then, the fins 211 and 212 are exposed and the exposed metal surfaces of the fins 211 and 212 opposite to the angle plates 221 and 222 are adhered by an adhesive 18 as shown in an enlarged view in FIG. This bonding step may be performed in the same manner as in the previous embodiment, and the same components as those in the previous embodiment are designated by the same reference numerals and the description thereof will be omitted.

First and second metal radiators 151 and 15
2 may be any structure, and in the embodiment shown in FIG. 5, the first and second metal radiators 151 and
152 is composed of fins 311 and 312 formed by folding an aluminum plate back into a rectangular shape. in this case,
Angle plates 321 and 312 are set on the outer surfaces of the fins 311 and 312 in the same manner as in the embodiment of FIG. 3, and a power source (not shown) is connected between the angle plates 321 and 322. To

In the embodiment shown in FIG. 6, the first
The second metal radiators 151 and 152 are made of a metal material such as aluminum and have a fish-bone (herringbone) fin 411.
And 412.

As shown in the above examples, the heating element 11
First and second metal radiators 15 that are set so as to sandwich
The structures of 1 and 152 can be set arbitrarily, and an anodic oxide film layer is formed on the surfaces of the metal radiators 151 and 152. .

FIG. 7 shows the result of an experiment on the buckling strength of the first and second metal heat radiators 151 and 152 in the case where an anodic oxide film layer (alumite layer) is formed in relation to the thickness of the alumite layer. Indicates. For this strength evaluation, length 1
A corrugated fin having a size of 00 mm × width 16 mm and height 9 mm was made of an aluminum plate having a thickness of 200 μm, and a compression load (buckling) was applied to the collect fin. Further, FIG. 8 shows the result of an experiment on the relationship between the thickness of the alumite layer and the electrical insulation strength.

From these experiments, it was found that the thickness of the alumite layer (anodic oxide film layer) is preferably 4 μm to 40 μm. That is, the thickness of the alumite layer is 4
When the thickness is less than μm, the insulating property is deteriorated. On the other hand, when the thickness exceeds 40 μm, the strength is deteriorated due to the formation of the alumite layer.

[0033]

As described above, according to the positive temperature coefficient thermistor heating device of the present invention, the insulating property of the metal radiator is surely secured, and there is no pressure loss when air or the like flows, and the thermal conductivity is high. Is well secured,
The reliability as well as the operation stability can be surely ensured.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a positive temperature coefficient thermistor heating device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a part of the heat generating device shown in FIG.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is an enlarged sectional view showing a part of the embodiment of FIG.

FIG. 5 is a sectional view showing a third embodiment of the present invention.

FIG. 6 is a diagram showing a fourth embodiment of the present invention.

FIG. 7 is a diagram showing the result of an experiment on the relationship between the film thickness of an anodized film (alumite layer) formed in this invention and the buckling strength.

FIG. 8 is a diagram showing the relationship between the thickness of the alumite layer and insulation resistance.

[Explanation of symbols]

11 ... Heating element (positive temperature coefficient thermistor), 121, 122 ... 1st
Angle plate, 131, 132 ... second angle plate, 141,
142 ... Corrugated fins, 151, 152 ... First and second
Metal radiator, 16 ... Power supply, 17 ... Anodized film layer (alumite layer), 18 ... Adhesive.

Claims (1)

Claim: What is claimed is: 1. A heating element using a positive temperature coefficient thermistor that generates heat when an electric current is supplied, a pair of metal radiators set in contact with both surfaces of the heating element, and a metal radiator of the metal radiator. A positive temperature coefficient thermistor heat generating device, comprising: an anodized film layer formed on an exposed surface, so that power is supplied to the heat generating element through the metal heat radiator.