JPH07176366A - Heater - Google Patents

Abstract

PURPOSE:To enhance productivity and to efficiently heat a subject for heating by providing a connector portion for connecting a metallic plate to an external power supply, and providing dents in the upper and lower flat surfaces of a package. CONSTITUTION:A connector portion 11a provided to a package 6 comprises a dent 12 provided in the lower flat surface 6b of the package 6 near one side of the package so that the end portion 5a of a metallic plate 5 below the connector portion is exposed and a dent 13 having a protrusion 13a provided on the upper flat surface 6a of the package 6. A contact portion is connected to the portion 5a of the plate 5 by insertion of a power plug into the portion 11a of the heater, and the engagement portion of the power plug engages with the protrusion 13a of the portion 11a. Then a current flows through the heating element 1, which is then heated. The power plug can be prevented from readily dropping from the heater. Also, making the power plug thinner than the package 6 enables any subject for heating to be efficiently heated and enables the productivity of the heater to be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat heater.

[0002]

2. Description of the Related Art Heretofore, a planar heater using a plate-shaped heating element made of barium titanate-based porcelain semiconductor, which is a positive temperature coefficient thermistor having a self-temperature control function, has been considered. This planar heater does not require a temperature control circuit for maintaining a constant heat generation temperature or an overheat prevention circuit for preventing overheating, and has extremely high safety.

In the above-mentioned sheet heater, electrodes are provided on the front surface and the back surface of the heating element, and lead wires are soldered to these electrodes to connect to an external power source, so that the heat generated by the heating element is heated. In order to transfer the heat evenly to the case, a case made of a molded article of ceramics such as alumina having excellent electrical insulation, heat resistance, mechanical strength and thermal conductivity, or an insulating sheet made of a thermoplastic resin, etc. The body is covered.

Since the lead wire is directly soldered to the electrodes provided on the front surface and the back surface of the heating element, there is a convex portion at that portion. If a space (gap) is formed between the case or the insulating sheet and the heating element, the thermal conductivity between the heating element and the object to be heated is reduced. Therefore, when covering the above heating element with a case, The case is provided with a concave portion in conformity with the soldering convex portion, and attention is paid to the adhesion between the case and the heating element.

[0005]

However, in the above conventional structure, when the heating element is covered with the insulating sheet, it is necessary to fix the heating element to the insulating sheet so that the heating element does not move in the insulating sheet. Therefore, there is a problem that an adhesive or the like must be used.

Further, when the heating element is covered with a case made of a ceramic molded product, this case needs to be separately prepared in advance, the planar heater becomes thicker, and the number of parts and the process for manufacturing the planar heater are increased. There is a problem that the number increases and the cost increases.

Further, since the above case is made of a ceramic molded product, it is poor in workability. Since it takes time to form unevenness in its shape, the case where the heating element has a low operating temperature and has heat resistance is not required. In this case, the above problem becomes more serious.

Therefore, there has been considered a planar heater in which a heating element is sandwiched between metal plates which also serve as a heat dissipation plate and an electrode plate, and an insulator is provided so as to cover them. In order to improve heat conduction, the metal plate and the insulator are integrally formed by compression molding. The lead wire for the power supply is connected to the metal plate before forming.

However, in this sheet heater, the lead wire or the connecting portion between the lead wire and the metal plate is damaged by the mold during molding, the electrical insulation of the lead wire is deteriorated, and the connecting portion is bent. There is a problem that

[0010]

In order to solve the above-mentioned problems, a heater according to the present invention has a plurality of heating elements having electrodes on the upper and lower surfaces and an upper surface of the heating element sandwiching these heating elements from above and below. , Two metal plates that electrically connect the electrodes of each other and the electrodes of the lower surface, an electrically insulating package that seals the heating element and the two metal plates, and two metal plates provided on the side surface of the package. The board is equipped with two connector parts for connecting an external power plug, the package has a flat top and bottom, and each connector part of the package is exposed so that the end of the metal plate is exposed. It is characterized by a recess provided on one flat surface near the side surface and a recess having a protrusion provided on the other flat surface to prevent the external power plug from coming off.

[0011]

According to the above construction, since the connector portion for connecting the metal plate and the external power source is provided, it is not necessary to previously connect the lead wire to the metal plate. Therefore, troubles such as deterioration of electric insulation of the lead wire at the time of manufacturing the heater are eliminated. Therefore, the productivity of the heater is improved. Moreover, since the connector portion is formed by providing the recesses on the upper and lower flat surfaces of the package, if the power plug is made thinner than the package,
The flat surface can be brought into close contact with the object to be heated. Therefore, the object to be heated can be efficiently heated.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

As shown in FIG. 1, the heater of this embodiment has a plurality of heating elements 1 having upper and lower electrodes 2 and 3, ...
Two metal plates 4 and 5 electrically sandwiching the heating elements 1 from above and below and electrically connecting the electrodes 2 on the upper surface and the electrodes 3 on the lower surface of the heating elements 1 ,. An electrically insulating package 6 for sealing the two metal plates 4 and 5 is provided.

As shown in FIG. 3, the package 6 has upper and lower flat surfaces 6a and 6b. On the side surface of the package 6, two connector parts 11 for connecting a power plug (described later) to the two metal plates 4 and 5
a.11b are provided.

The connector portion 11a is B- in FIG.
As shown in FIG. 1 which is a cross-sectional view taken along the line B, an indentation 12 is provided on a lower flat surface 6b near the side surface of the package 6 so that an end 5a of the lower metal plate 5 is exposed. , The upper flat surface 6 to make it difficult to pull out the power plug
and a recess 13 having a protrusion 13a provided in a.

The connector portion 11b is A- in FIG.
As shown in FIG. 2 which is a cross-sectional view taken along the line A, a recess 12 is provided in the upper flat surface 6a near the side surface of the package 6 so that the end 4a of the upper metal plate 4 is exposed, and a power source. To prevent the plug from coming off, the lower flat surface 6
and a recess 13 having a protrusion 13a provided in b.

As shown in FIG. 4, the power plug comprises a lead wire 22 and a metal clip 21 connected to the lead wire 22. The clip 21 has a contact portion 21a that electrically contacts the end portion 5a of the metal plate 5 (or the end portion 4a of the metal plate 4) and a protrusion that is caught by the protrusion 13a, and is an engagement that prevents the power plug from coming off easily. And a portion 21b.

In the above structure, the power plug is inserted into the connector parts 11a and 11b of the heater so that the contact part 21a of the power plug causes the end part 5a of the metal plate 5 of the connector part 11a (or the metal part of the connector part 11b). The end portion 4a of the plate 4 is connected to the engaging portion 21b of the power plug, and the protrusion 13a of the connector portion 11a (or,
It is caught by the protrusion 13a) of the connector portion 11b.

As a result, an electric current flows through the heating elements 1 ..., and the heating elements 1 ... Generate heat. Moreover, it is possible to prevent the power plug from easily coming off the heater. If the power plug is thinner than the package 6, the flat surfaces 6a and 6b can be brought into close contact with the object to be heated.
Therefore, the object to be heated can be efficiently heated.

Further, in the heater of this embodiment, compared with the conventional heater in which the lead wires are connected to the metal plates 4 and 5 in advance, the electric insulation of the lead wires during the manufacture of the heater is reduced. The trouble disappears in principle. Therefore, the productivity of the heater is improved.

The above-mentioned heater is specifically, for example, a disc-shaped heating element 1 made of a positive temperature coefficient thermistor,
A metal plate 4, 5 for sandwiching the heating element 1 from above and below, and a package 6 made of an electrically insulating resin
It has a sealed structure.

That is, the heating elements 1 ... Have low resistance from room temperature to the Curie temperature Tc (rapid temperature change of resistance), but when the temperature exceeds the Curie temperature Tc, the resistance value sharply increases. Characteristic thermistor. Due to this characteristic, when a voltage is applied from the power source, the heating elements 1 ... Initially have a low resistance value and a large current flows due to a low temperature. As a result, the temperature rises rapidly while the temperature rises. When the temperature exceeds the Curie temperature Tc, the resistance value sharply increases, so that the temperature does not rise above a certain temperature and the certain temperature is kept stable.

That is, the heating elements 1 ... Have a self-temperature control function. Therefore, the planar heater consumes less power, can omit the temperature control circuit and the overheat prevention circuit, and can be downsized. Further, there is no fear of ignition due to local overheating. Since the Curie temperature Tc of this heating element 1 can be arbitrarily set within the range of about 30 to 250 ° C. depending on the material composition, the heating element 1 in this embodiment has a package 6 effective for heating an object to be heated. The Curie temperature Tc may be set in consideration of safety and power saving.

As the metal plates 4 and 5, iron plates, stainless plates, copper plates, phosphor bronze plates, aluminum plates and the like are used. The metal plates 4 and 5 may be provided with holes. Further, it is not always necessary to use the same metal plates 4 and 5, but a metal plate with holes may be used for one and a metal plate without holes may be used for the other.

The heating element 1 and the metal plates 4 and 5 are electrically connected to each other by pressing them against each other. Alternatively, the heating element 1 and the metal plates 4 and 5 may be electrically connected by, for example, pasting with a conductive adhesive of epoxy resin / silver mixture.

The package 6 is integrally formed of a synthetic resin in which a filler containing long fibers is mixed, and the metal plate 4 is formed.
The heating element 1 and the metal plates 4 and 5 are hermetically sealed except for the end portions 4a and 5a of 5.

The recesses 12 and 13 of the package 6 are preferably provided when the package 6 is molded in order to manufacture a heater.
Although it is efficient, it may be provided by machining with a cutter or the like after molding the package 6.

The synthetic resin used for the package 6 has a small heat shrinkage ratio, is excellent in electrical insulation and mechanical strength, and has heat resistance capable of withstanding the heat generation temperature of the heating elements 1 ... It is necessary to have waterproofness that does not let air pass through and airtightness that does not let air pass inside. For example, thermosetting resin such as unsaturated polyester resin, vinyl ester resin, epoxy resin, phenol resin, or polypropylene resin. Thermoplastic resins such as polyamide resin and polyethylene terephthalate resin are used. The synthetic resin is appropriately selected according to, for example, the price, the affinity with the filler to be used, the molding method of the package 6, the use and size of the heater, the shape, the strength and various physical properties required for the heater, and the like. do it. Further, the synthetic resin may contain a curing agent, a release agent, a low-shrinking agent, a coloring agent, a thickening agent and the like.

The above-mentioned filler is excellent in thermal conductivity, electrical insulation and mechanical strength, and has heat resistance capable of withstanding the heat generation temperature of the heating elements 1 ... And has an affinity with synthetic resins. Is required, and for example, organic fiber, inorganic fiber, organic powder, inorganic powder or the like is used.

Examples of the organic fiber include cotton, wool,
Natural fibers such as hemp, chemical fibers such as rayon,
Synthetic fibers made of polyvinyl chloride resin, polyamide resin, wholly aromatic polyamide resin, saturated polyester resin or the like are used. As the inorganic fiber, for example, glass fiber, potassium titanate, boron, silicon carbide, alumina, polytitanocarbosilane and the like are used.

Further, as the organic powder, for example, rubber such as styrene-butadiene rubber is used. As the inorganic powder, for example, calcium carbonate, kaolin, clay, alumina, aluminum hydroxide, barium sulfate, lithopone, glass powder in the form of cut fibers or milled fibers, glass flakes, glass beads, glass microballoons, aluminosilicate microballoons. , Silica microballoons, wollastonite, boron nitride, fine particle silicon, ultra fine particle anhydrous silica,
Quartz powder, talc, mica, antimony trioxide, etc. are used.

The particle diameters of the above-mentioned organic powder and inorganic powder are not particularly limited. The forms of the organic powder and the inorganic powder are not particularly limited.

The above-mentioned filler may be appropriately selected depending on, for example, price, affinity with synthetic resin, molding method of package 6, size and strength of sheet heater, and various physical properties.

The amount of the filler mixed with the synthetic resin is not particularly limited.

The sheet heater formed by the package 6 is, for example, SMC (Sheet Molding Compound), B
Thermosetting resins such as MC (Bulk Molding Compound) are molded and manufactured by a heat compression molding method. Also,
The thermoplastic resin is molded and manufactured by compression molding in which the heated resin is cooled and compressed.

Molding of the planar heater by the above SMC
The manufacturing is performed by the following procedure. That is, first, a synthetic resin containing a filler (hereinafter referred to as a composite) is molded into three sheets each having a predetermined shape and size, and two of these sheets are used as an upper sheet and a lower sheet, while the rest are A hole having a size capable of accommodating the heating elements 1 ... Is opened at a predetermined position of the one sheet to be a perforated sheet. The thickness and forming method of these sheets are not particularly limited.

Then, the metal plate 5, the perforated sheet having the heating elements 1 ... Fitted in the holes, and the other metal plate 4 are placed on the lower sheet in this order at predetermined positions. Place the top sheet on top. Then, this laminate is placed in a mold (not shown) on a press molding machine, and pressed under predetermined conditions, that is, predetermined temperature, pressure, time, etc., to heat-harden the composite, and to form three sheets. Are integrated to form the package 6. As a result, the heating elements 1 ... And the metal plates 4 and 5 are sealed and fixed inside the package 6, and the planar heater is molded and manufactured.

The molding and manufacturing of the above-mentioned planar heater by BMC is carried out by the following procedure. That is, first, after the composite is made into a paste, the paste-like composite is expanded by a predetermined amount. Next, on the above-mentioned paste-like composite, the metal plates 4,5, the heating element 1, ... Expand the composite by a specified amount. After that, the composite is thermoset by pressing this laminate under predetermined conditions to form the package 6 and form a planar heater.

Further, the molding and manufacturing of the sheet heater made of the above thermoplastic resin is carried out by the following procedure. That is, first, the composite is formed into three sheets having a predetermined shape and size, and two of these sheets are used as the top sheet and the bottom sheet, while the remaining one sheet is perforated to form a perforated sheet. And The thickness and forming method of these sheets are not particularly limited.

Next, the above three sheets are heated to a predetermined temperature to be sufficiently melted, and a metal sheet 5, a heating element 1 ... The metal plate 4 is placed at a predetermined position in this order, and the top sheet is further placed on the metal plate 4. Alternatively, the sheets may be sufficiently melted by heating in the order described above and then heating. Then, the laminate is placed in a mold on a press molding machine and pressed under predetermined conditions to melt and cool the composite, and the three sheets are integrated to form the package 6, which is a planar heater. And

The procedure of molding and manufacturing the sheet heater made of SMC, BMC, and thermoplastic resin (stampable sheet) reinforced with long fibers is not limited to the above-mentioned procedure. It is sufficient if the procedure is such that the heating element 1 ... And the metal plates 4 and 5 are covered and sealed to form and manufacture the planar heater. Further, in compression molding, the perforated sheet may be omitted if there is no risk of the metal plates 4 and 5 coming into contact with each other during pressing. in this case,
The space between the heating element 1 and the metal plates 4 and 5 is filled with synthetic resin.

However, the fiber length of the filler is the same as that of the metal plate 4.
・ If the size of the hole is smaller than that of 5, the composite is placed on the upper and lower sides of the metal plates 4 and 5, and when pressed, most of the synthetic resin and the filler are pressed by the pressure. It passes through the holes and enters between the metal plates 4 and 5, so that almost no composite remains above and below the metal plates 4 and 5. Therefore, only extremely thin packages 6 are formed above and below the metal plates 4 and 5, respectively.
Is exposed on the surface of the package 6. That is, the electric insulation of the heating elements 1 ... and the metal plates 4 and 5 is not ensured, and it becomes impossible to use them as a planar heater.

The method for manufacturing the above heater will be described in detail below, but the present invention is not limited thereto. In addition, in the following specific examples, the shape of the planar heater is a flat rectangular shape.

A planar heater was molded and manufactured from a long fiber reinforced thermoplastic resin (stampable sheet). First, a stampable sheet manufactured by Cape La Sheet (product number: C8010-N, composition: polypropylene resin 60w
t%, glass fiber 40 wt%, thickness 0.85 mm) 1
The sheet was cut into 50 mm squares to obtain two sheets, an upper sheet and a lower sheet.

Furthermore, a cut of 5 mm square is formed on one side of the 150 mm square (this part is the connector portion 11a, 11b).
Was processed at a position of 50 mm on each side. In addition, the company's stampable sheet (product number: C80
40-N, composition: same as above, thickness 3.3 mm) 150 mm
After cutting in four directions, 5 holes with a diameter of 15 mm
A perforated sheet was formed by opening several places.

The lower surface has a diameter of 15 mm and a thickness of 2.5 m.
m heating element 1 is used, an aluminum foil (thickness 0.2 mm) is used as the metal plate 4 on the upper surface of the heating element 1, and 13 is used on the lower surface.
Aluminum plate cut to 0 mm square (thickness 0.2 m
m) was used as the metal plate 5.

When stacking, the stampable sheet on the upper surface and the stampable sheet on the lower surface were stacked so that the cuts were not located at the same position.

Next, the above-mentioned top sheet and bottom sheet were heated with an infrared heater for 2 minutes and 30 seconds, while the perforated sheet was heated for 4 minutes and 30 seconds to 200 ° C. A sheet is installed, an aluminum plate as a metal plate 5 and a perforated sheet are placed on the lower sheet in this order, and the heating element 1 is placed in the hole of the perforated sheet.
After being fitted, the aluminum foil as the metal plate 4 and the top sheet were placed in this order.

Thereafter, this laminate was heated at a temperature of 50 ° C. and a pressure of 1
Pressed at 0 kg / cm ^{2 for} 40 seconds, fused polypropylene resin, and integrated 3 sheets into 150 mm
A heater of × 150 mm × 4 mm was obtained. It was confirmed that the electric insulation of this heater was extremely good.

The heater according to the present invention has a plurality of heating elements 1 having electrodes 2 and 3 on the upper and lower surfaces, and the electrodes 2 on the upper surface of the heating elements 1 ... And two metal plates 4,5 for electrically connecting the electrodes 3 on the lower surface to each other, an electrically insulating package 6 for sealing the heating element 1 and the two metal plates 4,5, and a package 6. The two metal plates 4 and 5 provided on the side surface of the package are provided with two connector portions 11a and 11b for connecting an external power plug, and the package 6 has a flat surface 6a on the upper and lower sides.
The connector portion 11a (connector portion 11b) has an end portion 5a of the metal plate 5 (end portion 4 of the metal plate 4).
a recess 12 provided in the flat surface 6b (flat surface 6a) near the side surface of the package 6 so that a) is exposed;
Flat surface 6 to make it difficult to disconnect the external power plug
It is configured by a recess 13 having a protrusion 13a provided on a (flat surface 6b).

According to this, since the connector portions 11a and 11b for connecting the metal plates 4 and 5 to the external power source are provided, it is not necessary to connect lead wires to the metal plates 4 and 5 in advance. Therefore, troubles such as deterioration of electric insulation of the lead wire at the time of manufacturing the heater are eliminated. Therefore, the productivity of the heater is improved. Also, the upper and lower flat surfaces 6a and 6b of the package 6 have depressions 12 and 13.
Since the connector portions 11a and 11b are formed by providing the above, the flat surfaces 6a and 6b can be brought into close contact with the object to be heated by making the power plug thinner than the package 6. Therefore, the object to be heated can be efficiently heated.

[0052]

As described above, the heater according to the present invention has a plurality of heating elements having electrodes on the upper and lower surfaces, and those heating elements sandwiching the heating elements from above and below, and electrodes on the upper surface and electrodes on the lower surface of the heating element. Two electrically connected metal plates, an electrically insulating package that seals the heating element and the two metal plates, and an external power plug connected to the two metal plates provided on the side of the package The connector has two connector parts for the package, and the package has a flat surface on the top and bottom.Each connector part is on one flat surface near the side surface of the package so that the end of the metal plate is exposed. It is not necessary to connect the lead wire to the metal plate in advance, because the recess is provided and the recess having the protrusion is provided on the other flat surface to prevent the external power plug from coming off easily. Therefore, troubles such as deterioration of electric insulation of the lead wire at the time of manufacturing the heater are eliminated. Therefore, the productivity of the heater is improved. Also, if the power plug is thinner than the package,
The flat surface can be brought into close contact with the object to be heated. Therefore, there is an effect that the object to be heated can be efficiently heated.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a connector portion of a heater according to the present invention.

FIG. 2 is a vertical cross-sectional view showing a schematic configuration of the other connector portion of the heater according to the present invention.

FIG. 3 is a perspective view of a heater according to the present invention.

4A and 4B show a power plug used for a heater, in which FIG. 4A is a front view and FIG. 4B is a side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating element 2 Electrode 3 Electrode 4 Metal plate 4a End part 5 Metal plate 5a End part 6 Package 6a Flat surface 6b Flat surface 11a Connector part 11b Connector part 12 Cavity 13 Cavity 13a Protrusion

Claims (1)

[Claims] 1. A plurality of heating elements having electrodes on the upper and lower surfaces, and two metal plates sandwiching the heating elements from above and below and electrically connecting electrodes on the upper surface and electrodes on the lower surface of the heating element. It has an electrically insulating package that seals the heating element and the two metal plates, and two connector parts that are provided on the sides of the package and that connect the external power plug to the two metal plates. The package has a flat surface on the top and bottom, and each connector part has a dent on one flat surface near the side surface of the package so that the end of the metal plate is exposed, and it is difficult to pull out the external power plug. In order to do so, a heater comprising a recess having a protrusion provided on the other flat surface.