JP2014103076A - Positive temperature coefficient heating element, and hot air generating and supplying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive temperature coefficient heating element having good heat dissipation efficiency which generates heat by energization without increasing the temperature to a predetermined temperature or higher and to supply hot air generated by using the positive temperature coefficient heating element as a heat source.SOLUTION: The positive temperature coefficient heating element includes: a molded resistor 11 made of a mixture of sintering materials, whose main materials are aluminum powder, graphitic powder and clay powder, which is sintered after molding the external form by compression molding or extrusion molding and forming a plurality of through holes 12; and a pair of electrodes 13 and 14 formed on the molded resistor 11. Since the molded resistor 11 has a positive resistance temperature characteristic in which the resistance is low at normal temperature and the resistance suddenly increases when the temperature rises to a predetermined level, a mixture of sintering materials made by mixing aluminum powder, graphitic powder and clay powder becomes a strong and dense state by applying pressure to the mixture of sintering materials to form. Therefore, a high-strength positive temperature coefficient heating element 10 can be obtained by sintering in this state.

Description

The present invention relates to a positive heating element having a positive temperature coefficient having characteristics similar to those of a PTC (Positive Temperature Coefficient) thermistor and a hot air generating and supplying apparatus using the positive heating element. This positive characteristic heating element has a resistance temperature characteristic that resistance is low at room temperature, and the resistance rapidly increases when a predetermined temperature is reached. This type of positive heating element is an electrical product as a constant temperature heating element. The present invention relates to a positive-characteristic heating element that is frequently used in the above. Further, the present invention relates to a hot air generation and supply device that generates hot air using this as a heat source and supplies the generated hot air.

Sintered bodies obtained by firing powders of metals, metal oxides, and nitrides can be used in various fields because of their denseness, and many techniques have been developed.
In particular, an aluminum material as a metal material is lightweight, inexpensive, and has good workability. Therefore, an aluminum material has been conventionally studied as a raw material for producing a sintered body.
However, since aluminum materials are very easily oxidized and a stable and hard oxide film is easily formed on the surface thereof, it is difficult to obtain a sintered body having high mechanical strength even if it is sintered as it is.

By the way, the present applicant has previously filed a patent application of Patent Document 1 relating to the invention of a sintered body using aluminum powder. The invention of the sintered body described in Patent Document 1 contains aluminum fine particles, zeolite fine particles, an organic binder and / or an inorganic binder, and a mixture in which these are uniformly mixed is press-molded at room temperature and non-oxidized. Sintered at a temperature in the range of 1200 ° C. to 1800 ° C. in an atmosphere, and thereby a sintered body having excellent mechanical strength is obtained.

Japanese Patent Application No. 2010-179397

However, in the invention of Patent Document 1, since sintering was performed at a temperature in the range of 1200 ° C. to 1800 ° C., the obtained sintered body is mainly alumina, there is no current heat generation, and the resistor and resistance heating element The electrical conductivity suitable for such applications was not provided. For this reason, the application field could not be expanded as a sintered body using an aluminum material.
Conventionally used heating elements have been developed that are made of a metal material such as a nichrome alloy or a cantal (nickel / chromium) alloy or a ceramic material such as silicon carbide (SiC).
However, when a heating element made of a metal material is used as a heating element for liquid heating, an insulator such as magnesia needs to be disposed around the metal, and further, the whole needs to be wrapped with a metal sheath. In addition, the heat generation efficiency was low because the surface was radiated by a metal wire. On the other hand, a heating element made of a ceramic material is brittle and vulnerable to thermal shock caused by a rapid temperature change, and rapid heating and cooling are difficult.
In general, the resistance value of the heating element decreases as the temperature rises, and there is a risk of ignition depending on the energization time, and temperature control is indispensable from the outside by current or voltage control.

Accordingly, the present invention has been made to solve such a problem, and is a positive characteristic heating element that generates heat by energization and has high heat dissipation efficiency without increasing the temperature to a predetermined temperature or more, and the positive characteristic heating element. It is an object of the present invention to provide a hot air generation and supply device that generates hot air using a heat source and supplies the generated hot air.

The positive heating element according to claim 1 is formed by compression molding or extrusion molding a mixture mainly composed of aluminum powder, graphite powder, and clay powder, and is sintered. It has a positive resistance temperature characteristic in which the resistance rapidly increases when it rises to a predetermined temperature, and includes a molded resistor provided with a plurality of through holes and an electrode provided in the molded resistor.
Here, as the aluminum powder, for example, those having an irregular shape (needle shape, spindle shape, etc.) manufactured by an atomizing method (spray type) are used. The median diameter measured by the laser diffraction / scattering method is in the range of 30 μm to 75 μm and the particle diameter measured by the sieve test method is less than 150 μm, preferably the median diameter is in the range of 35 μm to 65 μm. Yes, the particle diameter is less than 100 μm.

By the way, according to definitions of terms in the text and explanation of JIS Z 8901 “Test Powder and Test Particles”, the median diameter is the number (or mass) larger than a certain particle diameter in the particle size distribution of the powder. ) is the particle diameter when occupying 50% of its Zenkonatai (diameter), i.e., a particle size of oversized 50%, usually expressed as the median diameter or 50% particle size and good D _50. By definition, the size of the particle group is expressed by the average particle diameter and the median diameter, but here, it is a value measured by the display of the product description and the laser diffraction / scattering method.
The “median diameter measured by the laser diffraction / scattering method” is a particle whose cumulative weight part is 50% in the particle size distribution obtained by the laser diffraction / scattering method using a laser diffraction particle size distribution measuring apparatus. This refers to the diameter (D ₅₀ ).
The above numerical values are not strict, but are approximate, and are naturally approximate values including errors due to measurement and the like, and do not deny errors of several percent.

Further, as the graphite powder, for example, one having a low thermal conductivity and not reacting with the aluminum powder even at a high temperature is selected. Here, any material that does not melt at a temperature lower than the melting point (668 ° C.) of the aluminum powder may be used, and examples thereof include powdery materials such as carbon, carbon black, activated carbon, and carbon fiber. Carbonaceous material fibers can be synthesized from petroleum pitch. Further, the purity of the graphite powder is preferably 90% or more. The graphite powder may be artificial graphite or natural graphite.
And the clay powder is a clay powder for ceramics as a mineral powder, for example, at least of aluminum oxide and silicon oxide, a composite oxide of aluminum oxide and silicon oxide, aluminum silicate Any material may be used as long as it contains one kind, and for example, glazed clay, kibushi clay, kaolin, feldspar, porcelain stone, zeolite powder and the like are used. The powder of the above-mentioned clay, kibushi clay, kaolin, feldspar, porcelain stone, and zeolite is usually called mineral powder and is a clay powder for ceramics.

A mixture mainly composed of aluminum powder, graphite powder, and clay powder is kneaded by adding water, and formed into an arbitrary shape by compression forming or pressing with a mold to press with a mold, For example, it is sintered in the range of 900 ° C. to 1100 ° C. in a temperature controlled electric furnace. Sintering in the temperature controlled electric furnace in the range of 900 ° C. to 1100 ° C. is a result of repeated experiments by the inventors, and as a result, sufficient sintering is not performed at temperatures lower than 900 ° C., resulting in poor sintering. It is confirmed that the lower limit of the sintering temperature is 900 ° C., and when it exceeds 1100 ° C., it is confirmed that the obtained formed body has a high probability of not having positive characteristics. The upper limit of the sintering temperature is 1100 ° C.
A molded resistor of a mixture mainly composed of aluminum powder, graphite powder, and clay powder has a low resistance at room temperature, and has a positive resistance temperature characteristic in which the resistance rapidly increases when the temperature rises to a predetermined temperature. Further, the plurality of through holes provided in the molding resistor are not particularly limited in cross-sectional shape, but those having a small air resistance and a large surface area are suitable.
Furthermore, the electrode provided on the molded resistor can be an electrode embedded in the molded resistor, or can be integrated at the same time through a metal sprayed on the surface or by enveloping with a sprayed metal. It can be formed as an electrode. This electrode is configured to obtain electrical continuity with the molded resistor from a terminal portion connected to a lead wire or the like.

The plurality of through holes provided in the molding resistor of the positive heating element according to claim 2 are each one or more of a cross-sectional circle, a cross-sectional ellipse, a cross-sectional oval, a cross-sectional triangle, a cross-sectional quadrangle, and a cross-sectional hexagon. It is a thing.
Here, a plurality of through-holes each having one or more of a circular cross-section, an elliptical cross-section, an oval cross-section, a triangular triangle, a square cross-section, and a hexagonal cross-section may be used in combination. And it is good also as a thing of a single kind, and may mix sizes.

The positive electrode of the positive characteristic heating element according to claim 3 is formed on both ends in the length direction of the molded resistor.
Here, the electrodes formed on both ends in the length direction of the molded resistor mean both ends of a plurality of through holes, and are not limited to the end, but are approximately 10 mm to 30 mm from the end. You may form using the one part or all part of the width | variety.

The positive electrode of the positive characteristic heating element according to claim 4 is formed on the opposite surface side in the direction perpendicular to the length direction.
Here, the electrode formed on the opposite surface side in the direction perpendicular to the length direction of the molded resistor means both side surfaces of the plurality of through holes, and the side surface in the length direction is limited to a rectangular plane. Alternatively, it may be an arcuate surface, or may be formed with a predetermined distance between the two, a predetermined resistance value is obtained, and the distribution state of the flowing current is substantially uniform.

The electrode of the positive heating element according to claim 5 is provided on the molding resistor by metal spraying.
Here, metal spraying is to melt and spray a spray material made of metal such as zinc, aluminum, copper, etc., and the metal in the case of carrying out the present invention is not particularly limited. Also, flame-type flame spraying, powder-type flame spraying, flame-type flame spraying, high-speed flame spraying, electric spraying, arc spraying, plasma spraying (low pressure plasma spraying, atmospheric plasma spraying, water plasma spraying), line explosion Either spraying or cold spraying may be used.

The molding resistor of the positive heating element according to claim 6 is a mixture in which aluminum powder 30-50 vol%, graphite powder 5-10 vol%, clay powder 30-50 vol%, wood powder 0-10 vol% are mixed. The whole is added with 15 to 25 vol% of water, kneaded, molded by compression or extrusion, dried, and sintered.
Here, when a mixture obtained by mixing aluminum powder, graphite powder, and clay powder for ceramics by specific blending is molded by applying pressure, these mixtures become a strong and dense solid state. Moreover, you may use it, melt | dissolving a binder with respect to water. Therefore, a high-strength molding resistor can be obtained by sintering in this state. Wood powder is not only related to porous voids, but also effective in a reducing atmosphere during sintering. However, if it is too much, the inside of the furnace is deteriorated with boil and odor is produced, so it is better to use less.

The molding resistor of the positive heating element according to claim 7 is a mixture obtained by further mixing 5 to 10 vol% of metal silicon and 0 to 10 vol% of iron powder.
Here, the metal silicon of 5 to 15 vol% increases the energization stability to ensure the energization as a non-participating material. Moreover, 0-5 vol% of iron powder can be used for resistance value control which functions as a resistor by oxidation, and can exhibit stable performance as a heating element. However, the mixing of metallic silicon and iron powder is not recommended to be mixed in large quantities because the properties as a positive characteristic heating element having a positive temperature coefficient having the same characteristics as the PTC thermistor deteriorate.

The apparatus for generating and supplying hot air according to claim 8 is formed by compressing or extruding a mixture containing aluminum powder, graphite powder, and clay powder as main materials and sintering, and has low resistance at room temperature. A positive resistance temperature characteristic in which the resistance rapidly increases when the temperature rises to a predetermined temperature, a plurality of through holes provided in the molding resistor, and an electrode provided in the molding resistor. A characteristic heating element and a blower for generating an air flow in a plurality of through holes provided for the molding resistor of the positive characteristic heating element are provided.
Here, as the aluminum powder, for example, those having an irregular shape (needle shape, spindle shape, etc.) manufactured by an atomizing method (spray type) are used. The median diameter measured by the laser diffraction / scattering method is in the range of 30 μm to 75 μm and the particle diameter measured by the sieve test method is less than 150 μm, preferably the median diameter is in the range of 35 μm to 65 μm. Yes, the particle diameter is less than 100 μm.
Further, graphite powder is usually selected that has low thermal conductivity and does not react with the aluminum powder even at high temperatures. Here, what is necessary is just a thing which does not melt at the temperature lower than the melting point (668 degreeC) of the said aluminum powder, for example, powdery substances, such as carbon, carbon black, activated carbon, carbon fiber, are mentioned. Carbonaceous material fibers can be synthesized from petroleum pitch. Further, the purity of the graphite powder is preferably 90% or more. The graphite powder may be artificial graphite or natural graphite.
And the clay powder is a clay powder for ceramics as a mineral powder, for example, at least of aluminum oxide and silicon oxide, a composite oxide of aluminum oxide and silicon oxide, aluminum silicate Any material may be used as long as it contains one kind, and for example, glazed clay, kibushi clay, kaolin, feldspar, porcelain stone, zeolite powder and the like are used. The powder of the above-mentioned clay, kibushi clay, kaolin, feldspar, porcelain stone, and zeolite is usually called mineral powder and is a clay powder for ceramics.

A mixture mainly composed of aluminum powder, graphite powder, and clay powder is kneaded by adding water, and formed into an arbitrary shape by compression forming or pressing with a mold to press with a mold, It is sintered in a temperature controlled electric furnace, for example, in the range of 900 ° C. to 1100 ° C. Sintering in the temperature controlled electric furnace within the range of 900 ° C. to 1100 ° C. is a result of repeated experiments by the present inventors. As a result, when the temperature is lower than 900 ° C., sufficient firing is not performed, resulting in poor sintering. It was confirmed that the lower limit of the sintering temperature was 900 ° C., and when it exceeded 1100 ° C., it was confirmed that the obtained formed body did not have positive characteristics. The upper limit is 1100 ° C.
The positive heat-generating base material of the mixture mainly composed of aluminum powder, graphite powder, and clay powder has a low resistance at room temperature, and a positive resistance temperature characteristic in which the resistance rapidly increases when the temperature rises to a predetermined temperature. Have.
Further, the plurality of through holes provided in the molding resistor are not particularly limited in cross-sectional shape, but those having a small air resistance and a large surface area are preferable.
Furthermore, the electrode provided on the molded resistor may be an electrode embedded in the molded resistor, or may be integrated by enveloping the sprayed metal on the surface or enveloping with the sprayed metal. It can be formed as an electrode. This electrode is configured to obtain electrical continuity with the molded resistor from a terminal portion connected to a lead wire or the like.
In addition, the blower for generating an air flow in a plurality of through holes provided in the molding resistor of the positive characteristic heating element is determined by the air resistance of the plurality of through holes, but a fan type, a sirocco type or the like It is not intended to limit.

The plurality of through holes provided in the molding resistor of the hot air generation and supply device according to claim 9 are each one of a cross-sectional circle, a cross-sectional ellipse, a cross-sectional oval, a cross-sectional triangle, a cross-sectional quadrangle, and a cross-sectional hexagon. Is.
Here, a plurality of through-holes each having one or more of a circular cross-section, an elliptical cross-section, an oval cross-section, a triangular triangle, a square cross-section, and a hexagonal cross-section may be used in combination. And it is good also as a thing of a single kind, and may mix large and small.

The electrodes provided on the molding resistor of the hot air generation and supply device according to claim 10 are formed on both ends of the positive heating element in the length direction.
Here, the electrodes formed on both end sides in the length direction of the molded resistor mean both end sides of the plurality of through holes, and are not limited to the most end portion. A part or all of the width of 30 mm may be used.

The electrode provided in the molding resistor of the hot air generation and supply device according to claim 11 is formed on the opposite surface side in the direction perpendicular to the length direction.
Here, the electrode formed on the opposite surface side in the direction perpendicular to the length direction of the molded resistor means both side surfaces of the plurality of through holes, and the side surfaces in the length direction are not limited to a rectangular plane. It may be an arcuate surface, or may be formed with a predetermined distance between them to obtain a predetermined resistance value, and the distribution state of the flowing current may be substantially uniform.

At least one blower for generating an air flow in a plurality of through holes provided for the molding resistor of the hot air generating and supplying apparatus according to claim 12 is disposed.
Here, it is also possible to diffuse the wind generated by the blower as a single blower, or to make two or more winds in the parallel direction. Also, a predetermined wind flow can be obtained by the fins.

The electrode provided with respect to the said molding resistor of the hot air generation supply apparatus of Claim 13 is provided in the molding resistor by metal spraying.
Here, the metal spraying is one in which a thermal spray material made of zinc, aluminum, copper or the like is melted and sprayed, and the metal in the case of carrying out the present invention is not particularly limited, and also in the thermal spraying method. Spray flame spraying, powder flame spraying, spray rod flame spraying, high-speed flame spraying, electric spraying, arc spraying, plasma spraying (low pressure plasma spraying / atmospheric plasma spraying / water plasma spraying), line explosion spraying Any of cold spray and the like may be used.

The molding resistor of the hot air generating and supplying apparatus according to claim 14 is a mixture in which aluminum powder is mixed in a blend of 30 to 50 vol%, graphite powder is 5 to 10 vol%, clay powder is 30 to 50 vol%, and wood powder is 0 to 10 vol%. In addition, 15 to 25 vol% of water is added to the whole, kneaded, molded by compression or extrusion, dried, and sintered.
Here, when a mixture obtained by mixing aluminum powder, graphite powder, and clay powder for ceramics by specific blending is molded by applying pressure, these mixtures become a strong and dense solid state. Moreover, you may use it, melt | dissolving a binder with respect to water. Therefore, a high-strength molding resistor can be obtained by sintering in this state.

Furthermore, it is set as the mixture which mixed metal silicon 5-10vol% and iron powder 0-10vol%.
The molding resistor of the hot air generation and supply device according to claim 15 is a mixture obtained by further mixing 5 to 10 vol% of metal silicon and 0 to 10 vol% of iron powder.
Here, the metal silicon of 5 to 15 vol% increases the energization stability to ensure the energization as a non-participating material. Moreover, 0-5 vol% of iron powder can be used for resistance value control which functions as a resistor by oxidation, and can exhibit stable performance as a heating element. However, the mixing of metallic silicon and iron powder is not recommended to be mixed in large quantities because the properties as a positive characteristic heating element having a positive temperature coefficient having the same characteristics as the PTC thermistor deteriorate.

The blower for generating an air flow in the plurality of through holes provided in the molding resistor of the hot air generating and supplying device according to claim 16 supplies electric power to the positive characteristic heating element and at the same time rotates the fan at a constant speed. It is to generate wind.
Here, it is possible to drive the blower at a constant speed from the beginning of energization of the positive characteristic heating element and perform the constant speed rotation after that by simple on / off control of the power source.

The blower for generating an air flow in a plurality of through holes provided for the positive characteristic heating element of the hot air generation and supply device according to claim 17 has a positive characteristic according to the positive resistance temperature characteristic of the positive characteristic heating element. It is detected from the peak value of the energization current that the heating element has risen to a predetermined temperature, and after detecting the peak value, warm air is generated by constant speed rotation of the blower.
Here, at the beginning of energization of the positive characteristic heating element, the fan may be driven at low speed rotation, and then the speed may be increased up to the peak value of the energization current, or the low speed rotation may be maintained. It may be. In any case, at the beginning of energization of the positive characteristic heating element, it is possible to drive the fan at low speed rotation and control it until it is led to constant speed rotation in a steady temperature state.

A blower for generating an air flow in a plurality of through holes provided in the positive characteristic heating element of the hot air generation and supply device according to claim 18, wherein the positive characteristic heating element corresponds to a positive resistance temperature characteristic of the positive characteristic heating element. Is detected by the peak value of the energizing current, and the fan is not energized until the peak value is detected, and the fan is rotated at a constant speed after the peak value is detected. By doing so, warm air is generated.
Here, it is determined that the positive characteristic heating element has reached a predetermined temperature based on a peak current value at which the positive characteristic heating element has risen to a predetermined temperature, and thereafter, the fan is operated at a constant speed. Is.

The humidity is also controlled simultaneously by dropping water droplets onto the molding resistor of the positive heating element of the hot air generating and supplying device according to claim 19 and placing the humidity on an air flow.
Here, the humidity control means that after a predetermined amount of humidity is raised at a predetermined time interval, the dropping of water drops is stopped and only temperature control is performed.

The positive heating element according to the invention of claim 1 is provided with a plurality of through-holes together with the outer shape by compression molding or extrusion molding of a mixture mainly composed of aluminum powder, graphite powder, and clay powder. A positive resistance temperature at which the resistance is low at room temperature, and the resistance rapidly increases as the temperature rises to a predetermined temperature. Since it has characteristics, by forming a mixture of aluminum powder, graphite powder, and clay powder for ceramics by applying pressure, the mixture becomes a strong and dense solid state. Therefore, by sintering in this state, a high-strength positive heat generating element can be obtained.
In addition, because graphite powder is mixed with the molding resistor, the graphite powder adheres to the surface of the aluminum powder, and the aluminum powder is covered with the graphite powder. However, there is no sintering failure in which aluminum is melted and ejected to the surface, and the mixture is compounded by firing to form a positive heating element having voids, and the positive heating element generates heat when energized. . As a result, the porous positive characteristic heating element has high mechanical strength and generates resistance by heating, and the porous positive characteristic heating element can be used as a resistance heating element that can rise to a specific temperature.

In particular, the porous positive heating element thus obtained has a high temperature rising rate by energization and a temperature lowering rate by de-energization for a large volume, and the heat generation temperature becomes constant depending on the energization amount. Therefore, resistance control in the manufacturing process is easy. That is, by selecting the particle shape and particle size distribution of the raw material, adjusting the blending amount, adjusting the pressure during molding, and adjusting the density of the positive heating element, By adjusting the sintering temperature by adjusting the sintering temperature, it is possible to control the heat generation temperature by energization by controlling the resistance value of the molding resistor. Also, it is possible to specify the molding resistor by adjusting the resistance distribution of the molding resistor by adjusting the molding shape, etc. at the time of molding, adjusting the filling amount during molding, and adjusting the partial pressure during molding. The site can be heated to a specific temperature.
Therefore, the porous positive heating element according to the present invention is suitable for use as a resistance heating element, and particularly suitable for use as a heating element heated on the surface. In addition, it is chemically strong such as acid. In this way, a porous positive heating element having high mechanical strength and energizing heat generation and suitable for use as a resistance heating element is obtained. And, since it is resistant to heat shock and can be converted into water vapor instantly even when a water droplet is dropped, it can be used as a heat source for humidity control simultaneously with temperature control.

Here, the void in the positive characteristic heating element has a sufficient strength even if it is used as a resistance heating element within a predetermined range as a result of repeated research by the inventors. In addition, it was found that energization heat generation can be secured. That is, when there are few voids in the molded resistor, the resistance value of the positive heating element is small and the heat generation due to energization is impaired. On the other hand, when there are too many voids in the molded resistor, the strength is insufficient in use as a resistance heating element, and the electrical conductivity is impaired.
The voids of the molded resistor are measured by measuring the volume and weight of the formed molded resistor in a dry state, measuring the weight in a state impregnated with water, measuring the weight again by drying, and measuring the weight of the molded resistor. The change is replaced with porosity. Moreover, the paraffin was impregnated in the place deaerated in a vacuum by the “paraffin permeation apparatus (ULVAC DA-15D)” and calculated from the change in the weight, as a result, there was no significant difference. Therefore, here, the former and the latter will be described without distinction.
Therefore, a positive characteristic heating element with good heat dissipation efficiency can be obtained without generating heat and increasing the temperature above a predetermined temperature.

  The plurality of through holes provided for the molded resistor of the positive heating element according to the second aspect of the present invention may be any one of a cross-sectional circle, a cross-sectional ellipse, a cross-sectional oval, a cross-sectional triangle, a cross-sectional quadrangle, and a cross-sectional hexagon. Therefore, in addition to the effect of the first aspect, since the heat radiating surface is not restricted to a specific shape, a positive characteristic heating element with improved heat radiating effect can be obtained. Moreover, the form according to the speed of the flow of an air flow is employable by setting the fluid resistance of several through-holes to arbitrary values. And the external shape can be made into arbitrary shapes.

  Since the electrodes provided on the molded resistor of the positive heating element according to the invention of claim 3 are formed on both ends in the length direction of the molded resistor, the electrode according to claim 1 or 2. In addition to the above effect, the electrodes formed on both ends in the length direction of the molded resistor means that a current flows from one end side to the other end side of the plurality of through holes. Since the electric circuit becomes a complicated path other than a straight line, heat generation from the entire molded resistor can be expected.

  Since the electrode provided for the molded resistor of the positive heating element according to the invention of claim 4 is formed on the opposite surface side in the direction perpendicular to the length direction, the electrode according to claim 1 or claim 2 is provided. In addition to the effects described above, the electrode formed on the opposite surface side in the direction perpendicular to the length direction of the molded resistor means that a voltage is applied to both side surfaces of the plurality of through holes. Since the heat is generated at the thinnest part of the cross-sectional shape of the molded resistor, the entire molded resistor can be heated substantially uniformly. In particular, since a voltage is applied during a short distance of the molded resistor, a predetermined amount of heat can be generated at a low voltage.

  The electrode provided on the molding resistor of the positive heating element according to the invention of claim 5 is provided on the molding resistor by metal spraying, and therefore any one of claims 1 to 4. In addition to the effects described in (2), if the electrode provided for the molded resistor is embedded in the molded resistor, the electrode may be melted in relation to the firing temperature during firing. However, in the case of metal spraying, the metal to be sprayed is not specified because it may be performed when the molding resistor is completed. In addition, the molded resistor takes the form of a porous heating element, but can be connected to the terminal of the lead wire in a state in which the surface area is utilized, the heat generation of the electrode can be extremely reduced, and the long life Become.

The molding resistor of the positive heating element according to the invention of claim 6 is mixed by blending aluminum powder 30-50 vol%, graphite powder 5-10 vol%, clay powder 30-50 vol%, wood powder 0-10 vol% The mixture is kneaded by adding 15 to 25 vol% of water to the whole, molded by compression molding or extrusion molding, dried, and then sintered. Claims 1 to In addition to the effect described in any one of 5, the following effect is achieved.
That is, in the mixture, for example, when the content of aluminum powder is less than 30 vol%, the aluminum powder is too small and the electrical conductivity is impaired. On the other hand, when the content of aluminum powder exceeds 50 vol%, the portion of the aluminum powder that is not covered with graphite powder increases, which tends to cause poor sintering in which molten aluminum is ejected to the surface during the firing process. .
For example, if the content of the graphite powder is less than 5 vol%, the portion of the aluminum powder that is too small to be covered with the graphite powder increases, so that the aluminum melted in the firing process is on the surface. It becomes easy to produce the sintering defect which spouts. On the other hand, if the content of the graphite powder exceeds 10 vol%, the graphite powder is too much and the strength and purity of the molded resistor is lowered, and the strength and current exothermicity are sufficient when the porous heating element is used as the resistance heating element. It will not be.
And if the content of clay powder for ceramics is less than 30 vol%, for example, there is too little clay powder for ceramics, the resistance value of the resulting molded resistor becomes small, and the resistance heating element of the porous heating element As a result, the energization heat generation is insufficient. On the other hand, if the content of the clay powder for ceramics exceeds 50 vol%, the clay powder for ceramics is too much and the conductivity is impaired.

Further, wood powder obtained by finely pulverizing wood chips with a pulverizer is used, but a whisker-like one is preferably used. For example, by using whisker-like wood powder, raw materials such as aluminum powder, graphite powder, and clay-like clay powder are entangled in whisker-like crevice-like gaps, so that the filling property of the raw material is increased and pressure is increased in the molding process. Although what is produced by applying the above becomes strong and dense, a molded resistor can be obtained even without wood powder. Usually, it is desirable to add 0 to 10 vol%.
Therefore, according to the positive-characteristic heating element of the present invention, it is surely high in strength and energizing heat generation and high in purity.
In the mixture, the aluminum powder content is in the range of 40 vol% to 45 vol%, the graphite powder content is in the range of 5 vol% to 10 vol%, and the mineral powder (for ceramics) When the content of (clay powder) is in the range of 40 vol% to 45 vol%, it is more preferable since high strength and purity as well as energization exothermicity can be secured in the porous positive heating element.

  Since the molding resistor of the positive heating element according to the invention of claim 7 is a mixture obtained by further mixing 5 to 10 vol% of metal silicon and 0 to 10 vol% of iron powder, the effect of claim 6 is achieved. In addition, since it contains 5 to 15 vol% of metallic silicon and 0 to 5 vol% of iron powder, it is possible to ensure energization stability. Since iron powder functions as a resistor when oxidized, it can be used for resistance value control, and if necessary, controls whether or not to make a positive characteristic heating element having a positive temperature coefficient having the same characteristics as a PTC thermistor. it can.

The apparatus for generating and supplying hot air according to the invention of claim 8 is formed by compressing or extruding a mixture mainly composed of aluminum powder, graphite powder, and clay powder, and sintering the mixture. A molded resistor having a positive resistance temperature characteristic in which the resistance is low and the resistance rapidly increases when the temperature rises to a predetermined temperature, a plurality of through holes provided in the molded resistor, and a surface of the molded resistor Since it comprises a positive heating element comprising an electrode, and a blower for generating an air flow in a plurality of through holes provided for the positive heating base of the positive heating element, aluminum powder, By forming a mixture of graphite powder and clay powder for ceramics by applying pressure, these mixtures become a strong and dense solid state. Therefore, by sintering in this state, a high-strength positive heat generating element can be obtained.
In addition, since graphite powder is mixed with the molding resistor of the positive heating element, the graphite powder adheres to the surface of the aluminum powder, and the aluminum powder is covered with the graphite powder. Even when the melting point of (660.4 ° C.) is reached, there is no sintering failure in which aluminum melts and spouts onto the surface, and the mixture is compounded by firing to form a molding resistor having voids, Such a molded resistor generates heat when energized. As a result, the porous positive characteristic heating element has high mechanical strength and generates resistance by heating, and the porous positive characteristic heating element can be used as a resistance heating element.

In particular, the porous positive heating element thus obtained has a high temperature rising rate by energization and a temperature lowering rate by de-energization for a large volume, and the heat generation temperature becomes constant depending on the energization amount. Therefore, resistance control in the manufacturing process is easy. That is, by selecting the particle shape and particle size distribution of the raw material, adjusting the blending amount, adjusting the pressure during molding, and adjusting the density of the positive heating element, By adjusting the sintering temperature by adjusting the sintering temperature, it is possible to control the heat generation temperature by energization by controlling the resistance value of the molding resistor. Also, it is possible to specify the molding resistor by adjusting the resistance distribution of the molding resistor by adjusting the molding shape, etc. at the time of molding, adjusting the filling amount during molding, and adjusting the partial pressure during molding. The site can be heated to a specific temperature.
Therefore, the porous positive heating element according to the present invention is suitable for use as a resistance heating element, and particularly suitable for use as a heating element heated on the surface. In addition, it is chemically strong such as acid. In this way, a porous positive heating element having high mechanical strength and energizing heat generation and suitable for use as a resistance heating element is obtained. And it is strong against heat shock, and even when a water droplet is dropped, it can be instantaneously converted into water vapor, so that humidity control can be performed simultaneously with temperature control.

Here, the voids of the positive resistance heating element molded resistor may be used as a resistance heating element as long as the voids in the molded resistor are within a predetermined range as a result of repeated experiments by the inventors. It has been found that sufficient strength and energization heat generation can be secured. That is, if the voids of the molded resistor are small, the resistance value of the positive heating element is small and the heat generation due to energization is impaired. On the other hand, when there are too many voids in the molded resistor, the strength is insufficient in use as a resistance heating element, and the electrical conductivity is impaired.
Further, by the blower that generates an air flow in the plurality of through holes provided in the molding resistor of the positive characteristic heating element, the heat radiation from the positive characteristic heating element can move the hot air to the destination by the air flow. . Therefore, the amount of heat can be easily moved.
Therefore, it generates heat by energization, generates hot air using the positive heating element with good heat dissipation efficiency and the positive heating element as a heat source without increasing the temperature above a predetermined temperature, and supplies the generated hot air. It can be carried out.

  The plurality of through-holes provided in the molding resistor of the hot air generating and supplying device according to the invention of claim 9 are each one of a circular cross-section, a cross-sectional ellipse, a cross-sectional oval, a cross-sectional triangle, a cross-sectional quadrangle, and a cross-sectional hexagon. Since it is one, in addition to the effect of claim 8, since the heat radiation surface is not constrained to a specific shape, a positive characteristic heating element with improved heat radiation effect can be obtained. Moreover, the form according to the speed of the flow of warm air can be employ | adopted by setting the fluid resistance of several through-holes to arbitrary values. The outer shape has a high degree of freedom and can be an arbitrary shape.

The electrodes provided on the molded resistor of the hot air generating and supplying apparatus according to the invention of claim 10 are formed on both ends in the length direction of the molded resistor. In addition to the above effect, the electrodes formed on both ends of the positive characteristic heating element in the length direction mean that a current flows from one end side to the other end side of the plurality of through holes, and the current is actually energized. Since the energization path is a complicated path other than a straight line, heat generation from the entire positive heating element can be expected.
Therefore, since the heat generated in the positive characteristic heating element is generated in two-dimensional and three-dimensional spaces, it can be configured in accordance with the intended use.

  The electrode provided on the molding resistor of the hot air generation and supply device according to the invention of claim 11 is formed on the opposite surface side in the direction perpendicular to the length direction. In addition to the effect of the above, the electrode formed on the opposite surface side in the direction perpendicular to the length direction of the molding resistor means that a voltage is applied to both side surfaces of the plurality of through holes, and in principle, molding is performed. Since the heat is generated at the thinnest part of the cross-sectional shape of the resistor, the entire molded resistor can generate heat almost uniformly. Therefore, by setting the fluid resistance of the plurality of through holes to an arbitrary value, the temperature distribution of the vertical cross section with respect to the air flow can be made substantially uniform. In particular, since a voltage is applied during a short distance of the molded resistor, a predetermined amount of heat can be generated at a low voltage.

  Since at least one blower for generating an air flow in the plurality of through holes provided in the molding resistor of the hot air generating and supplying device according to the invention of claim 12 is disposed, In addition to the effect described in any one of 11, it is possible to freely select the diffusion direction or the parallel direction of the air flow, and to set the direction of the wind guided by the fin receiving the wind of the blower.

  Since the electrode provided on the molding resistor of the hot air generating and supplying apparatus according to the thirteenth aspect of the invention is provided on the molding resistor by thermal spraying of metal, any one of claims 8 to 12 is provided. In addition to the effects described in the above, the electrode provided on the molded resistor may be melted at the firing temperature during firing when embedded in the molded resistor, but in the case of thermal spraying, the molded resistor was completed. Since what is necessary is just to carry out at the time, the metal to spray is not specified. In addition, the molded resistor takes the form of a porous positive heating element, but it can be connected to the terminal of the lead wire in a state where its large surface area is used, and extremely reduce the heat generation of the electrode. And long life.

The molding resistor of the hot air generating and supplying device according to the invention of claim 14 is a blend of aluminum powder 30-50 vol%, graphite powder 5-10 vol%, clay powder 30-50 vol%, wood powder 0-10 vol%. Since the mixture is kneaded by adding 15 to 25 vol% of water to the whole, molded by compression molding or extrusion molding, dried and then sintered. In addition to the effect described in any one of Items 13, according to the positive heat generating element of the present invention, it is sure to have high strength, energization heat generation, and high purity.
That is, in the mixture, when the content of the aluminum powder is less than 30 vol%, the aluminum powder is too small and the electrical conductivity is impaired. On the other hand, when the content of aluminum powder exceeds 50 vol%, the portion of the aluminum powder that is not covered with graphite powder increases, which tends to cause poor sintering in which molten aluminum is ejected to the surface during the firing process. .

Also, if the graphite powder content is less than 5 vol%, the graphite powder is too small and the portion of the aluminum powder that is not covered with the graphite powder increases, and as a result, molten aluminum is ejected to the surface during the firing process. Sintering failure is likely to occur. On the other hand, if the content of the graphite powder exceeds 10 vol%, the graphite powder is too much and the strength and purity of the molded resistor is lowered, and the strength and current exothermicity are sufficient when the porous heating element is used as the resistance heating element. It will not be.
And if the content of clay powder for ceramics is less than 30 vol%, the amount of clay powder for ceramics is too small, the resistance value of the resulting molded resistor becomes small, and as a resistance heating element of the porous heating element In use, the energization heat generation is insufficient. On the other hand, if the content of the clay powder for ceramics exceeds 50 vol%, the clay powder for ceramics is too much and the conductivity is impaired.

Further, wood powder obtained by finely pulverizing wood chips with a pulverizer is used, but a whisker-like one is preferably used. By using whisker-like wood powder, raw materials such as aluminum powder, graphite powder, and clay-like clay powder get entangled in whisker-like gaps in the whisker. The resulting product is strong and dense, but a molded resistor can be obtained even without wood flour. Usually, it is desirable to add 0 to 10 vol%.
Therefore, according to the positive-characteristic heating element of the present invention, it is surely high in strength and energizing heat generation and high in purity.
In the mixture, the aluminum powder content is in the range of 40 vol% to 45 vol%, the graphite powder content is in the range of 5 vol% to 10 vol%, and the mineral powder (for ceramics) It is more preferable that the content of (clay powder) is in the range of 40 vol% to 45 vol%, since it is possible to ensure high strength and purity as well as energization exothermicity in the porous heating element.

  The molding resistor of the hot air generating and supplying device according to the invention of claim 15 is a mixture in which 5-10 vol% of metal silicon and 0-10 vol% of iron powder are further mixed. In addition, 5 to 15 vol% of metallic silicon and 0 to 5 vol% of iron powder are blended, so that current-carrying stability can be ensured. Since iron powder functions as a resistor when oxidized, it can be used for resistance value control, and if necessary, controls whether or not to make a positive characteristic heating element having a positive temperature coefficient having the same characteristics as a PTC thermistor. it can.

  The blower that generates an air flow in the plurality of through holes provided in the molding resistor of the hot air generation and supply device according to claim 16 is heated by constant speed rotation of the blower simultaneously with the supply of electric power to the positive characteristic heating element. Since the wind is generated, in addition to the effect described in any one of claims 8 to 14, the blower is driven at a constant speed from the beginning of energizing the positive heating element. Then, performing constant speed rotation can send warm air by simple on / off control of the power source, and can suppress the overshoot of the current generated at the Curie point temperature somewhat lower than the actual.

  The blower for generating an air flow in a plurality of through holes provided in the molding resistor of the hot air generation and supply device according to claim 17, wherein the positive characteristic heating base material is in accordance with a positive resistance temperature characteristic of the positive characteristic heating element. Is detected by the peak value of the energizing current, and after the peak value is detected, warm air is generated by constant speed rotation of the blower. In addition to the effect described in any one of the above, at the beginning of energization of the positive heating element, the fan is driven at a low speed, or at the beginning of energization of the positive heating element. Means that the fan is driven at a rotation corresponding to it, and then the peak value of the energization current means that the temperature at which the positive heating element can be rotated normally is exceeded, so the fan is then operated at a constant speed. There are eyes from the beginning of energization It is temperature control by tailored blower, gradually temperature of the wind of the blower is possible to control the temperature with no discomfort because the rise.

  The blower for generating an air flow in a plurality of through holes provided for the molding resistor of the hot air generating / supplying device according to claim 18, wherein the molding resistor is in accordance with a positive resistance temperature characteristic of the positive characteristic heating element. Is detected by the peak value of the energizing current, and the fan is not energized until the peak value is detected, and the fan is rotated at a constant speed after the peak value is detected. In addition to the effects described in any one of claims 8 to 14, in addition to the effect described in any one of claims 8 to 14, a positive current heating element is positively controlled by a peak current value that has risen to a predetermined temperature. By determining that the characteristic heating element has reached a predetermined temperature and thereafter operating the blower at a constant speed, it is possible to recognize the start of supply of the predetermined hot air. Therefore, the coolness of the wind of the blower is not felt at the beginning of energization. Further, the rotation control of the blower is simple.

  Since the humidity control is performed simultaneously by dropping water droplets on the molding resistor of the positive heating element of the hot air generating and supplying device of claim 19 and placing the humidity on an air flow. In addition to the effects of any one of Items 8 to 14 and 16 to 18, temperature control and humidity control can be performed simultaneously, and in particular, it is possible to prevent the humidity from decreasing in winter. it can.

FIG. 1 is a flowchart showing a method for manufacturing a positive heating element according to the first embodiment of the present invention. FIG. 2 shows a molding example of the positive heating element according to the first embodiment of the present invention. (A) is a cylindrical molding resistor, and (b) is a cylindrical metal sprayed molding resistor. (C) is an example in which an electrode is provided by a cylindrical molded resistor. FIG. 3 shows a molding example of a positive heating element according to a modification of the first embodiment of the present invention. (A) is a rectangular parallelepiped molding resistor, and (b) is a rectangular parallelepiped metal spray. A molded resistor (c) is a rectangular parallelepiped molded resistor in which electrodes are arranged. FIG. 4 is an explanatory diagram showing the positional relationship between the molded resistor and the electrode according to the first embodiment of the present invention. FIG. 5 is a perspective view of a positive heating element according to a modification of the first embodiment of the present invention. FIG. 5A is a positive heating element and a main part of a rectangular parallelepiped molded resistor provided with a through-hole having a square cross section. It is AA sectional drawing, (b) is a positive-characteristic heating element of the rectangular parallelepiped molded resistor which provided the through-hole with a circular cross section. FIG. 6 is a perspective view of a combination of a positive heating element and a blower of a cylindrical molded resistor used in the hot air generating and supplying apparatus according to the second embodiment of the present invention. FIG. 7 is a modified example of a combination of a positive heating element and a blower used in the hot air generating and supplying apparatus according to the second embodiment of the present invention, and a combination of a positive heating element and a blower of a rectangular parallelepiped molded resistor. FIG. FIG. 8 is an explanatory diagram showing an arrangement relationship of the hot air generation and supply device according to the second embodiment of the present invention. FIG. 9 is a characteristic diagram of the positive heating element according to the first embodiment of the present invention, where (a) is a temperature-resistance characteristic diagram, (b) is a time-current characteristic diagram, and (c) is a time-air volume control. FIG. FIG. 10 is a circuit block diagram of the hot air generating and supplying apparatus according to the second embodiment of the present invention. FIG. 11 is a flowchart of a program for controlling the hot air generating and supplying apparatus according to the second embodiment of the present invention. FIG. 12 is an explanatory diagram and a control circuit block diagram showing the arrangement relationship of the hot air generation and supply device according to a modification of the second embodiment of the present invention. FIG. 13: is a flowchart of the program which controls the hot air generation supply apparatus concerning the modification of Embodiment 2 of this invention.

Hereinafter, a positive heating element and a warm air generation and supply device according to embodiments of the present invention will be described with reference to the drawings.
In the embodiments, the same symbols and the same reference numerals mean the same or corresponding functional parts of the embodiments, and the same symbols and the same reference numerals with the embodiments mean the functional parts common to the embodiments. Therefore, the detailed description which overlaps is abbreviate | omitted here.

[Embodiment 1]
First, a method for manufacturing the positive heating element of Embodiment 1 of the present invention will be described with reference to FIG.
The porous positive heating elements 10 and 20 of the first embodiment include aluminum powder 2, graphite powder 3 as carbon powder, and clay mesh powder 4 that is clay powder for ceramics as an inorganic oxide material. Depending on the case, it is manufactured using wood powder 5, water and / or binder 6. Here, the wood powder 5 is useful for strengthening the heat shock after firing. Further, it is possible to omit the water and / or the binder 6 and fire it as a solidified powder.

  As shown in the flowchart of FIG. 1, in the positive heating elements 10 and 20 of the first embodiment, first, in the sintering raw material mixing step of Step S1, the aluminum powder 2, the graphite powder 3, and the mesh Clay powder 4, wood powder 5, water 6 and / or binder are mixed to form a sintered raw material mixture 7.

  Here, as the aluminum powder 2, a commercially available aluminum powder can be used, and such aluminum powders are Minalco Co., Ltd., Nippon Light Metal Co., Ltd., Toyo Aluminum Co., Ltd., Daiwa Metal Powder Co., Ltd. Etc. are on sale. Further, the aluminum powder 2 can be used not only with 100% aluminum but also with a slight amount of impurities such as inorganic substances or recycled aluminum, and further contains a slight amount of metal such as iron or copper. It is also possible to use aluminum alloy powder or the like.

  The aluminum powder 2 preferably has a median diameter measured by a laser diffraction / scattering method in the range of 30 μm to 75 μm and a particle diameter measured by a sieve test method of less than 150 μm. That is, the filling property is improved by combining small particles and large particles. Further, if the median diameter of the aluminum powder 2 is less than 30 μm, the aluminum powder 2 may be easily melted at a low temperature during the firing process and may be ejected to the surface, while the median diameter of the aluminum powder 2 is 75 μm. When exceeding, the part which is not covered with the graphite powder 3 will increase, and it may become easy to produce the sintering defect by which the aluminum fuse | melted in the baking process ejects on the surface. Even when the particle diameter measured by the sieving test method of the aluminum powder 2 is 150 μm or more, the portion not covered with the graphite powder 3 increases, and as a result, the sintered aluminum in which molten aluminum is ejected to the surface during the firing process. Is likely to occur. More preferably, the median diameter of the aluminum powder 2 measured by the laser diffraction / scattering method is in the range of 35 μm to 65 μm, and the particle diameter measured by the sieve test method is less than 100 μm.

The graphite powder 3 as the carbon powder does not melt at a temperature lower than the melting point of the aluminum powder 2, and a commercially available graphite powder can be used as the graphite powder 3. And such graphite powder is marketed by Nishimura Graphite Co., Ltd., Nippon Graphite Industry Co., Ltd., Ito Graphite Industry Co., Ltd., Chuetsu Graphite Industry Co., Ltd., etc. Commercial graphite powder includes natural graphite such as scaly graphite and earthy graphite, and artificial graphite such as long columnar granulated graphite obtained by granulating scaly natural graphite powder into a long columnar shape. It is preferable to use natural scaly graphite, which is considered high. By using scaly graphite, it is easy to get entangled and adhered to the aluminum powder 2, and it is possible to effectively suppress the sintering failure in which aluminum is ejected to the surface due to the melting of the aluminum powder 2.

The graphite powder 3 preferably has a median diameter measured by a laser diffraction / scattering method in the range of 60 μm to 90 μm and a particle diameter measured by a sieve test method of less than 200 μm. This is also because the filling property is improved by combining the small-diameter particles and the large-diameter particles.
Further, if the median diameter of the graphite powder 3 is less than 60 μm, the graphite powder 3 is liable to be liquefied during the firing process, and a sintering failure in which aluminum is ejected to the surface is likely to occur. On the other hand, when the median diameter of the graphite powder 3 exceeds 90 μm, the graphite powder 3 becomes difficult to be uniformly dispersed and mixed, and the portion of the aluminum powder 2 that is not covered with the graphite powder 3 increases, Sintering defects in which aluminum is ejected to the surface during the firing process tend to occur. Even when the particle diameter of the graphite powder 3 measured by the sieving test method is 200 μm or more, the portion of the aluminum powder 2 that is not covered with the graphite powder 3 increases, resulting in poor sintering in which aluminum is ejected to the surface during the firing process. It becomes easy. More preferably, the median diameter of the graphite powder 3 measured by the laser diffraction / scattering method is in the range of 70 μm to 80 μm, and the particle diameter measured by the sieve test method is less than 150 μm.

Sasame clay powder 4 as a clay powder for ceramics is made from the weathered residual clay formed by weathering and depositing granite, which has been refined and powdered by elutriation (separation of silica sand and clay), aluminum This is a clay powder containing a main component of kaolin which is Al ₂ Si ₄ 0 ₁₀ (OH) ₈ , which is a mixture of quartz, feldspar, mica and the like. In general, according to chemical analysis, the amount of aluminum oxide Al ₂ O ₃ and silicon oxide SiO ₂ is the largest, and in addition, Fe ₂ O ₃ , TiO ₂ , CaO, MgO, Na ₂ O , K ₂ O and other components are contained, but the amount of the component varies depending on the place of production, etc. Therefore, if Al ₂ O ₃ and SiO ₂ are mainly contained, other components and composition ratios are not particularly limited. Absent. As this Sasame clay powder 4, for example, a commercially available Sasame clay powder marketed by Yamas Corporation, Kyoritsu Material Co., Ltd. or the like can be used.

In addition, this square clay powder 4 has a median diameter measured by a laser diffraction / scattering method in the range of 5 μm to 30 μm, and a particle diameter measured by a sieve test method is less than 100 μm. This is because the packing property is improved by combining the diameter particles.
Further, it is costly to obtain a fine powder having a median diameter of less than 5 μm, and when the median diameter of the mesh clay powder 4 is less than 5 μm, Changes in the composition of the mesh clay powder 4 are likely to occur, and it may not be possible to ensure performance such as stable strength and energization exothermicity in the pre-sintered molded body 8 (see 8A in FIG. 2 and 8B in FIG. 3) described later. . On the other hand, if the median diameter of the Sasame clay powder 4 exceeds 30 μm, the Sasame clay powder 4 is difficult to be uniformly dispersed and mixed, resulting in an uneven distribution, or changes in the components of the Sasame clay powder 4 due to heat. As a result, there is a possibility that performance such as stable strength and energization heat generation may not be ensured in the pre-sintered molded body 8.
Similarly, even when the particle size measured by the sieve test method of the square mesh powder 4 is 100 μm or more, the uniform clay powder 4 is hardly uniformly dispersed and confused, resulting in uneven distribution, or due to heat. The component change of the clay powder 4 is likely to occur. Accordingly, there is a possibility that performance such as stable strength and energization exothermicity cannot be secured in the pre-sintered molded body 8.
More preferably, the median diameter of the square clay powder 4 measured by the laser diffraction / scattering method is in the range of 10 μm to 20 μm, and the particle diameter measured by the sieve test method is less than 70 μm.

The wood powder 5 is obtained by finely pulverizing wood chips such as large sawdust, thinned wood chips, small-diameter wood, lumber mill ends, and bark with a pulverizer, but is preferably a whisker. By using the whisker-like wood powder 5, raw materials such as aluminum powder 2, graphite powder 3 and glazed clay powder 4 are entangled in the whisker-like gaps of the whisker. What is generated by applying pressure in the molding process described later is strong and dense. The pre-sintered molded body 8 obtained by sintering the molded mixture has a very high strength.

The wood powder 5 preferably has a median diameter measured by a laser diffraction / scattering method in the range of 80 μm to 120 μm and a particle diameter by a sieve test method of less than 200 μm. This is because the filling property is improved by the combination of the small diameter particles and the large diameter particles. In addition, it is costly to obtain a fine powder having a median diameter of less than 80 μm of wood powder 5. On the other hand, if the median diameter of wood powder 5 exceeds 120 μm, the wood powder 5 is uniformly dispersed and mixed. Therefore, there is a possibility that the distribution of voids due to burning is biased and stable strength is not ensured in the pre-sintered molded body 8. Further, even when the particle diameter of the wood powder 5 by the sieve test method is 200 μm or more, the wood powder 5 is difficult to be uniformly dispersed and mixed, and the distribution of voids due to burning is uneven, and the pre-sintered molded body 8 is stable. Strength is not secured. More preferably, the median diameter of the wood powder 5 measured by the laser diffraction / scattering method is in the range of 50 μm to 100 μm, and the particle diameter measured by the sieve test method is less than 150 μm.

In order to economically obtain the wood powder 5 having a particle diameter of less than 200 μm, the wood chips such as thinned wood, small diameter wood, bark, sawn timber, and large sawdust are dried to a water content of 20 parts by weight or less and then pulverized. There is a need. This is because by drying the wood chips to a water content of 20 parts by weight or less, the pulverized product can be prevented from becoming a slurry and preventing fine pulverization. Further, in order to finely pulverize the dried wood chips to obtain a wood powder 5 having a particle diameter of less than 200 μm, it is preferable to use a fine pulverizer having a peripheral speed in the range of 50 m / sec to 80 m / sec. An example of such a fine pulverizer is a micron colloid mill manufactured by Kawamoto Tekko Co., Ltd.
Here, conifers such as cedar (Japanese cedar) and Japanese cypress (Japanese cypress) are widely distributed in Japan and are used in large quantities as building materials, etc., so it is easy to obtain large amounts of sawdust, thinned wood and bark. Can do. Furthermore, the fine structure of coniferous trees is whisker-like, and can be easily pulverized into wood powder 5. Therefore, in terms of raw material collection and national land conservation, it is preferable to use coniferous large sawdust or coniferous thinning chips or coniferous bark as large sawdust and thinned wood chips and bark.

In the first embodiment, the aluminum powder 2, the graphite powder 3, the square clay powder 4 and the wood powder 5 have an amount of water that does not move due to the difference in specific gravity (an amount that does not cause gravity sedimentation) and water. When the binder 6 is mixed, the clayey clay powder 4 is a clay mineral substance, which functions advantageously to ensure moldability or shape retention, and the raw materials are bonded to each other by hand. The sintered raw material mixture 7 is obtained in a state that is not collapsed even when gripped. The sintered raw material mixture 7 thus obtained is in a state in which the graphite powder 3 is adhered to the surfaces of the aluminum powder 2 and the wood powder 5.

In the first embodiment, a precision dispersion mixer is used for mixing these raw materials, and aluminum powder 2, graphite powder 3, square clay powder 4 and wood powder 5 are uniformly dispersed and mixed and sintered. The raw material mixture 7 is obtained. In addition, as the precision dispersion mixer, it is preferable to use a high-speed stirring disperser within a peripheral speed range of 5 μm / second to 80 m / second, more preferably within a peripheral speed range of 20 m / second to 30 m / second. As such a high-speed stirring disperser, for example, there is a horizontal turbulizer (registered trademark) manufactured by Hosokawa Micron Corporation.

Further, in the first embodiment, since the raw clay powder 4 is used as a raw material, the raw materials are easily bonded together by simply mixing a small amount of water 6. The sintered raw material mixture 7 can be molded and strengthened simply by pressurizing with an organic binder or an inorganic binder for bonding the raw materials when the present invention is carried out. It is possible to use water and a binder together.
Here, as the “organic binder”, for example, synthetic resin, starch, synthetic glue, sugar and the like can be used. Synthetic resins include thermoplastic resins and thermosetting resins, and polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, acrylic resins, polyurethane resins, etc. should be used as thermoplastic resins. As the thermosetting resin, phenol resin, epoxy resin, polyol resin, isocyanate resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, urethane prepolymer and the like can be used. Of these, the polyol resin and the isocyanate resin react at room temperature to form a strong bond. In particular, the isocyanate resin reacts with the hydroxyl group (—OH) in the wood powder 5 and the like to form a strong urethane bond. In order to form, the sintered raw material mixture 7 is very strong and dense.

“Inorganic binders” include hydraulic materials such as cement, clays such as bentonite, which is a raw material of porcelain (tile) and ceramics, ρ-alumina (Al ₂ O ₃ · nH ₂ O: n≈0.5), silica Sodium sulfate, water-soluble alkali silicic acid, silica binder manufactured by Japan Nanocoat Co., Ltd., general-purpose binder FJ294, which is a silica binder manufactured by Grandex Co., Ltd., and the like can be used.
Note that the organic binder is burned off in the heating process to form voids, and the inorganic binder is baked without being burned out.

Further, in the case of carrying out the present invention, as in the resin molding method, water 6 is put into the aluminum powder 2, the graphite powder 3, the square clay powder 4 and the wood powder 5 to obtain a slurry-like sintered raw material mixture 7. Can be used for the molding process of step S2 after filling the mold and hardening. Further, as in the production of ceramics and porcelain (tile), the sintered raw material mixture 7 can be dried by a spray dryer and then subjected to the forming process in step S2. Further, the powder-only sintering raw material mixture 7 can be hardened without using water and / or the binder 6. In any case, the means for adhering water and / or raw materials and the type of binder are not particularly limited as long as a solidified state can be produced so that the shape can be maintained in the firing process described later.

Next, in the first embodiment, this sintering raw material mixture 7 is pressed at room temperature in the molding step of Step S2 to form a strong and dense solid pre-sintered molded body 8.
Here, in the molding process, the sintering raw material mixture 7 is put into a press molding die and molded by a press with a predetermined pressure, and the sintering raw material mixture 7 is put into a pressure-resistant mold and extruded at a predetermined pressure. Extrusion molding or the like is possible.

By the way, in the first embodiment, since the clay mesh powder 4 is used as the raw material, a small amount of water and / or the binder 6 can be mixed or eliminated as described above, so that the raw materials can be easily mixed. It will be in a state of being glued together. For this reason, it can shape | mold by low pressure by pressurization at normal temperature. Therefore, it is not always necessary to use a press device with high pressure or heating equipment, and the cost can be reduced.
Specifically, when the water and / or a binder 6 by mixing sintered raw material mixture 7 is press-formed, the pressing pressure is preferably in the range of ^{10kg / cm 2 ~200kg / cm 2} . If the pressure of the press molding is less than 10 kg / cm ² , the sintered raw material mixture 7 is not sufficiently compressed, so that the strength of the obtained pre-sintered molded body 8 is weakened and may be damaged in the firing process described later. . On the other hand, when the pressure of the press molding exceeds 200 kg / cm ² , the pressure is applied to the sintering raw material mixture 7 so that it becomes a high density, the resistance value of the pre-sintered molded body 8 becomes small, and the sintered porous body becomes porous. There is a possibility that the energization exothermic property of the high-quality molded resistors 11 and 21 (see FIGS. 2 and 3) may be impaired. Moreover, there is a possibility of sintering failure. More preferably, in the range of ^{50kg / cm 2 ~150kg / cm 2} . In particular, as the amount of moisture increases, molding at a lower pressure becomes possible.

  And in this Embodiment 1, since it can shape | mold by normal temperature pressurization and the uniform heating from the outside is unnecessary, in the case of press molding, the thick pre-sintering molded body 8 (for example, It is also possible to obtain up to about 20 mm thickness with a 150 ton press. Furthermore, since a heating mechanism is not required, it is possible to obtain a large-area pre-sintered molded body 8 (for example, 1000 mm × 2000 mm) by simplifying the structure of the press molding machine and the mold. In addition, as a press molding machine at this time, the powder molding press machine of 150 tons or more can be used, for example. According to this press machine, since a mechanism capable of degassing is provided during molding, a high-strength one can be stably obtained by molding. Of course, as will be described later, for example, a mold having irregularities, a mold frame having a curved portion, or the like is used, and irregularities are formed on the design surface of the sintering raw material mixture 7 by molding. It is also possible to mold into a desired shape.

  On the other hand, in the case of extrusion molding, the sintering raw material mixture 7 can be formed into a complicated shape such as a curved cylindrical shape or rod shape. In particular, since the sintering raw material mixture 7 formed by mixing water and / or the binder 6 has good moldability, the cross-sectional circle, the cross-sectional ellipse, the cross-sectional oval, the cross-sectional triangle, the cross-sectional square, and the hexagonal cross-section are formed by extrusion molding. It is also possible to form in a very complicated shape such as (honeycomb shape). Thus, the extrusion-molded pre-sintered molded body 8A (see FIG. 2) and the injection-molded pre-sintered molded body 8B (FIG. 3) according to the first embodiment shown in FIGS. Reference) is obtained.

In carrying out the present invention, of course, the sintered raw material mixture 7 can be formed by heating and pressing. In particular, in the present invention, mineral powder such as Sasame clay powder 4 is used, and this functions advantageously to ensure moldability or shape retention. Molding is possible without mixing. Incidentally, the press molding pressure when heating and pressing without mixing water and binder is preferably in the range of ^{50kg / cm 2 ~300kg / cm 2} . If the pressure of the press molding is less than 50 kg / cm ² , the strength of the sintered raw material mixture 7 is not sufficiently compressed when water or a binder is not mixed, and the strength may be weakened and may be damaged in the firing process described later. . On the other hand, when the pressure of the press molding exceeds 300 kg / cm ² , the pressure is applied to the sintering raw material mixture 7 so as to have a high density, and the resistance values of the resulting molding resistors 11 and 21 become small, and firing is performed. Even if it does, the energization exothermic property of the molding resistors 11 and 21 may be impaired. More preferably, in the range of ^{100kg / cm 2 ~200kg / cm 2} . However, depending on the resistance value and the composite component, there may be used outside the range of ^{100kg / cm 2 ~200kg / cm 2} .

Subsequently, the formed sintered raw material mixture 7 is sintered in a temperature controlled electric furnace within a range of 900 ° C. to 1100 ° C. in the sintering step of Step S3.
Here, the sintering temperature is in the range of 900 ° C. to 1100 ° C. As a result of repeated experiments by the present inventors, when the temperature is lower than 900 ° C., a powdered product is obtained without sufficient firing. Since it was confirmed that the sintering was poor, the lower limit value of the sintering temperature was set to 900 ° C., and on the other hand, when the temperature exceeded 1100 ° C., the obtained molded resistors 11 and 21 had current-generating heat generation properties. Since it was confirmed that there was no upper limit, the upper limit of the sintering temperature was 1100 ° C.
Note that the temperature raising program for the sintering process was previously tested according to the type of each raw material, particle size, blending amount, resistance value required for the pre-sintered molded body 8 (8A, 8B) described later, heat generation temperature, and the like. The optimum value is set by.
And, by sintering in the range of 900 ° C. to 1100 ° C. in this way, the molded resistors 11 and 21 having positive characteristics are obtained. The positive molded resistors 11 and 21 thus obtained have a resistance-temperature characteristic that the resistance is low at room temperature, and the resistance rapidly increases when the temperature reaches a predetermined temperature. To do. In particular, the molded resistors 11 and 21 dissipate heat over the entire surface and have a large surface area because they are porous.

After firing the positive molded resistors 11 and 21 in step S3, electrode films 13a and 14a are formed by spraying metal (implemented with aluminum) at desired positions of the molded resistors 11 and 21 in step S4. Since the molded resistors 11 and 21 are porous, the electrode films 13a and 14a are more firmly bonded to the molded resistors 11 and 21. The electrode film 13 a and the electrode film 14 a formed on the molded resistor 11 are formed on the end side in the length direction of the molded resistor 11. Thereafter, the electrode film 13a and the electrode film 14a are overlaid with the copper electrode terminal 13b and the copper electrode terminal 14b so as to embed the bases of the copper electrode terminal 13b and the copper electrode terminal 14b in step S5, and then sprayed again to form the electrode film. 13a and the electrode film 14a and the copper electrode terminal 13b and the copper electrode terminal 14b can be embedded and fixed together.
Here, since the opposing surfaces of the electrode film 13a and the electrode film 14a and the copper electrode terminal 13b and the copper electrode terminal 14b cannot be joined, the base part of the copper electrode terminal 13b and the copper electrode terminal 14b facing the electrode film 13a and the electrode film 14a. It is desirable to increase the bonding force between the two by drilling a hole in the hole or by forming irregularities in the shape of a vein (rear coast) on the outer periphery.

In the present embodiment, the copper electrode terminal 13b and the copper electrode terminal 14b are superimposed on the electrode film 13a and the electrode film 14a so that the copper electrode terminal 13b and the copper electrode terminal 14b are embedded in the molded resistor 11 in step S5. Although the thermal spraying is performed again, the electrode film 23a and the electrode film 24a are similarly applied to the molded resistor 21 by spraying the electrode film 23a and the electrode film 24a and the copper electrode terminal 23b and the copper electrode terminal 24b or by attaching them to a metal melting furnace. The copper electrode terminal 23b and the copper electrode terminal 24b can be welded with metal. Thus, the electrode film 23a and the electrode film 24a, the copper electrode terminal 23b and the copper electrode terminal 24b are attached to a metal melting furnace, and the opposing surfaces of the copper electrode terminal 23b and the copper electrode terminal 24b are welded with metal. Is coated with a molten metal, the mechanical strength is increased and the electrical resistance is also lowered, and a preferable connection state is obtained.
Thus, the porous positive characteristic heating elements 10 and 20 of the first embodiment are obtained.

FIG. 2A shows an electrode film 13a, an electrode film 14a, a copper electrode terminal 13b, and a copper electrode terminal 14b that are integrally provided by thermal spraying on both ends of a molded resistor 11 having a cylindrical outer shape. In 3 (a), the electrode film 23a, the electrode film 24a, the copper electrode terminal 23b, and the copper electrode terminal 24b are integrally provided by thermal spraying on both ends of the molded resistor 21 whose outer shape is a rectangular parallelepiped.
However, as shown in FIG. 4, the electrode film 13a, the electrode film 14a, the copper electrode terminal 13b, and the copper electrode terminal 14b are integrally formed on the opposing surface in the direction perpendicular to the length direction of the cylindrical molded resistor 11. It can also be provided. In particular, the current paths of the molding resistors 11 and 21 at this time are determined by the thickness of the meat around the openings of the plurality of through holes 12 and the through holes 22, and heat is generated around the plurality of through holes 12. Efficiency can be improved. That is, although not shown, it is preferable to form portions other than the plurality of through holes 12 and 22 with a uniform thickness and a small thickness.

Further, as shown in FIG. 5A, the electrode film 23a, the electrode film 24a, the copper electrode terminal 23b, and the copper electrode terminal 24b are provided on the opposing surfaces in the direction perpendicular to the length direction of the rectangular parallelepiped molded resistor 21. It can also be provided integrally. In particular, the current path at this time is determined by the thickness of the meat around the openings of the plurality of through holes 12, and heat is generated around the plurality of through holes 22, so that the heat dissipation efficiency can be improved.
In FIG. 5, since the opposing surfaces of the electrode film 23a and the electrode film 24a and the copper electrode terminal 23b and the copper electrode terminal 24b cannot be joined by thermal spraying, as shown in FIG. 5, the copper electrode terminal 23b and the copper electrode terminal 24b By drilling holes in the base portions facing the electrode film 23a and the electrode film 24a, the length of the silhouette line on the outer periphery is increased and the bonding force between the two is increased. In this method, the electrical conductivity can be improved and the mechanical strength can be increased in the same manner as in the case of being integrally joined by the molten metal. As the copper electrode terminal 23b, when a perforated thin plate of aluminum, stainless steel, copper or the like is used, the mechanical strength is increased. Further, it is more effective to cut the joint portion of the copper electrode terminal 23b to leave a smooth surface.

Specifically, as shown in FIGS. 2 (a) to 2 (c), a porous columnar positive characteristic heating element 10 has a plurality of internal through-holes 12 each having a circular cross section and a cylindrical outer shape. It consists of a resistor 11 and a pair of electrodes 13 and 14 formed by spraying metal on both ends of the molded resistor 11. The pair of electrodes 13 and 14 are formed after the sintering raw material mixture 7 is formed, and after firing the pre-sintered molded body 8A in which a plurality of through holes 12 are formed by a mold in step S2 of the molding process, The electrodes 13 and 14 are formed by thermal spraying in S4 and step S5. In addition, the electrode 13 and the electrode 14 in the first embodiment are made of aluminum. Since the metal spraying is performed after the sintering process, the metal is not melted by being exposed to a high temperature, and therefore any metal can be used for the electrode 13 and the electrode 14. Incidentally, in the experiments by the inventors, the copper electrode terminal 13b and the copper electrode terminal 14b were made of aluminum, copper, brass, stainless steel or the like selected as a low resistance material.
Further, as shown in FIGS. 3A to 3C, the positive porous heating element 20 having a porous shape as a whole has a rectangular parallelepiped molded resistor 21 and surfaces of both ends of the molded resistor 21. It consists of a pair of electrodes 23 and 24 joined by thermal spraying. The electrode 23 and the electrode 24 are made of copper, and are formed by thermal spraying on the molded resistor 21 formed in the sintering process of step S3.

In the positive characteristic heating elements 10 and 20 of the first embodiment, the pair of electrodes 13 and 14 and the electrodes 23 and 24 are formed by metal spraying. However, when the present invention is implemented, the positive characteristic heating elements are formed. 10 or the positive heating element 20 itself, that is, an electrode (not shown) may be embedded in the molded resistor 11, 21 or an electrode may be bonded to the end surface, or the molded resistor 11, 21 may be strongly pressed. It is good also as a structure to do. In any case, it is desirable that the terminal can be energized with a low contact resistance.
In FIG. 2, a porous columnar positive characteristic heating element 10 has a plurality of internal through holes 12 each having a circular cross section. In FIG. 3, the porous rectangular parallelepiped positive-characteristic heating element 20 has a plurality of internal through holes 22 each having a square cross section. However, the plurality of through-holes 12 and through-holes 22 formed in the molded resistors 11 and 21 are not limited to a circular cross-section and a quadrilateral cross-section, respectively. One or more of a cross-sectional triangle, a cross-sectional quadrangle, and a cross-sectional hexagon can be used. Moreover, the size of the cross-sectional shape of the through-holes 12 and 22 is also an arbitrary size, and a plurality of sizes can be combined. Arbitrary shapes can be selected as the overall outer shape.

Further, as shown in FIG. 2, the pair of electrodes 13 and 14 of the molded resistor 11 of the positive heating element 10 can be formed on both ends in the length direction of the molded resistor 11, Further, as shown in FIG. 5A, it can be formed on the opposite surface side in the direction perpendicular to the length direction.
In particular, the pair of electrodes 13 and 14 of the molded resistor 11 is provided on the molded resistor 11 by metal spraying, and the sprayed electrode film 13a and electrode film 14a are connected to the electrode terminal 13b and electrode terminal 14b. The electrode terminal 13b and the electrode terminal 14 can be formed by casting after being provided on the molded resistor 11 by metal spraying.
When the electrodes 13, 14, 23, 24 of the molding resistors 11, 21 of the positive characteristic heating elements 10, 20 are provided, the molding resistors 11, 21 are improved in order to improve finishing accuracy and mounting properties. The surface, in particular, the surface on which the electrode film 23a and the electrode film 24a are formed can be polished to increase the accuracy. Even after mechanical polishing, the resistance value hardly changed.
As described above, a pair of electrodes 23 and 24 can be formed on the positive heating element 20 as well as the positive heating element 10.

According to the experimental study by the present inventors, the following characteristics were confirmed for the positive heating elements 10 and 20 of the above embodiment.
It was confirmed that the resistance values of the positive heating elements 10 and 20 vary depending on the particle shape, blending amount and type of raw material, and the pressure during molding. The reason seems to be that the density of the porous positive heating elements 10 and 20 varies depending on the particle shape, blending amount and type of the raw material, and the pressure during molding. Specifically, for example, when coarse particles are used as the raw material, the resistance value becomes larger than when fine particles are used, and the resistance value increases as the press pressure at the time of molding increases.

  Therefore, according to the porous positive heating elements 10 and 20 of the first embodiment, the denseness of the positive heating elements 10 and 20 can be adjusted by adjusting the particle shape, blending amount and type of raw material, and the pressure during molding. By changing the degree, it is possible to control the resistance value of the positive heating elements 10 and 20. Incidentally, it has been confirmed by experimental studies by the present inventors that the resistance value of the positive heating elements 10 and 20 decreases when the density of the positive heating elements 10 and 20 is increased. Therefore, the heat generation only at a desired position to be heated can be increased.

  In particular, according to the positive heating elements 10 and 20 of the first embodiment, the wood powder 5 is used as a raw material, and in the firing process, the wood powder 5 is burned off, so that the portion becomes a void, and the positive This greatly affects the denseness of the characteristic heating elements 10 and 20. For this reason, the resistance value of the porous positive characteristic heating elements 10 and 20 can be easily controlled by adjusting the amount of the wood powder 5 added.

In addition, the resistance values of the positive heating elements 10 and 20 can be changed by variously adjusting the sintering temperature within the sintering temperature range of 900 ° C. to 1100 ° C. according to experimental studies by the present inventors. Is known. This seems to be because the sintering density (the density of particles in the firing process) changes depending on the sintering temperature. Therefore, it is possible to control the resistance values of the positive heating elements 10 and 20 also by adjusting the sintering temperature.
In addition, since the resistance values of the positive heating elements 10 and 20 change depending on their shapes and also change depending on the energization amount, it is possible to adjust the shape and energization amount so The resistance values of the positive characteristic heating elements 10 and 20 can be controlled.

  Furthermore, in this way, according to the positive characteristic heating elements 10 and 20 of the first embodiment, the resistance value of the positive characteristic heating elements 10 and 20 is influenced by the density, that is, the compression pressure. When the sintered raw material mixture 7 is formed, the resistance distribution can be controlled in the positive heating elements 10 and 20 by adjusting the density distribution. That is, different heat generation temperatures can be set depending on the parts of the molded resistors 11 and 21, and specific parts of the porous positive characteristic heat generation elements 10 and 20 can be heated to a specific temperature.

Here, as a method of adjusting the density distribution when the sintered raw material mixture 7 is molded, the mold shape at the time of molding, the adjustment of the molding shape by extrusion molding, the adjustment of the raw material filling amount at the time of molding, Examples include partial pressure adjustment during molding, and a plurality of protrusions formed on the compression surface.
Specifically, for example, press molding the sintered raw material mixture 7 using a mold having irregularities during press molding. As a result, a concavo-convex portion is formed on the design surface, and a product having greatly different densities can be obtained between the concave portion and the convex portion. The molding resistors 11 and 21 obtained by sintering the concave portions and the convex portions having greatly different densities are greatly different in resistance values between the concave portions and the convex portions. Are greatly different in the heat generation temperature due to energization in the uneven part.

In addition, by pressing the sintered raw material mixture 7 using a mold having a curved portion during press molding, a material having a large change in density at the curved portion can be obtained. Then, the resistance values of the molded resistors 11 and 21 formed by sintering this change greatly at the curved portion, and the heat generation temperature due to energization of the porous positive characteristic heating element 1 varies greatly depending on the part.
Furthermore, during press molding, the press mold is filled with the filling ratio of the sintering raw material mixture 7 changed, and press-molded, and the thickness of the sintering raw material mixture 7 is changed depending on the part. Since the density changes due to the difference in filling amount and thickness by molding, the resistance values of the molded resistors 11 and 21 obtained by sintering are also greatly changed depending on the part, and the porous positive characteristics The heat generating elements 10 and 20 have greatly different heat generation temperatures depending on the parts.

Hereinafter, the positive characteristic heating elements 10 and 20 of the first embodiment are used by being attached as follows. In the second embodiment, an example of a hot air generating and supplying apparatus used for heating an automobile shown in FIGS. 6 to 8 will be described.
First, as shown in FIG. 8, a duct 50 formed of a synthetic resin or a metal plate is disposed on a route for circulating inside the vehicle and a route for sucking air from the outside of the vehicle. The duct 50 will be described on the assumption that it is a quadrangular cylinder, but it may be a cylinder or a bellows.
The duct 50 is provided with an outside air port 51 for taking in outside air and an inside air port 52 for taking in and circulating the inside air. Further, the air outlet of the air is arranged as an air supply port 53 provided in the dashboard, and the air taken in from the vehicle outside air port 51 or the vehicle interior air port 52 is supplied from the air supply port 53 into the vehicle.

The two outside air ports 51 and the inside air port 52 are combined into one duct via a switching valve 54, and the intake of air from the outside air port 51 and the inside air port 52 is taken in depending on the opening / closing angle of the switching valve 54. The amount is controlled.
A blower 60 is disposed at a position in the duct 50 closer to the air supply port 53 than the position of the switching valve 54. The blower 60 may be provided in an isolated manner, or the two blowers 60 are connected to each other and rotated in a direction that cancels the direction of rotation of the wind generated by the first blower. You may generate a wind parallel to. Of course, instead of the two blowers 60, parallel winds may be generated by fins. The number and capacity of the blowers 60 are determined by the fluid resistance of the positive heating elements 10 and 20, the amount of air used, and the like.
It should be noted that when one blower 60 is arranged alone, it must be considered that the wind flows spirally, but the static pressure generated by the blower 60 is guided to the positive heating elements 10 and 20 in the diameter direction of the blower 60. By blocking the flow of the wind, the airflow flowing through the through holes 12 and 22 of the positive characteristic heating elements 10 and 20 can be rectified.

As shown in FIG. 6, the pair of electrodes 13 and 14 of the molded resistor 11 of the positive characteristic heating element 10 are provided on the molded resistor 11 by metal spraying, and the sprayed electrode film 13a and electrodes The film 14a, the electrode terminal 13b, and the electrode terminal 14b are integrally provided.
One blower 60 is integrally joined to one end of the molding resistor 11 of the positive characteristic heating element 10 so as not to leak air. The blower 60 is attached to the duct 50 by means (not shown) using the main body 61. Moreover, the sealing property between them is also ensured.
Strictly speaking, the output of the general-purpose blower 60 is vortex, but the plurality of through holes 12 formed in the molding resistor 11 of the positive heating element 10 are parallel to the vortex centerline of the blower 60. Therefore, the air is discharged from the through hole 12 on the electrode 13 side while contacting the peripheral surface of the through hole 12, and the wind is supplied from the air supply port 53 into the vehicle.

  Since the positive heating element 10 is attached to the duct 50 by the main body 61 of the blower 60, it is in a so-called cantilever state. Therefore, it is an insulator and is formed between the inner surface of the duct 50 by the cushioning material 63 which is a foam. Is provided with positioning, sealing and buffering properties. As a result, even if a pair of electrodes 13 and 14 of the molded resistor 11 of the positive characteristic heating element 10 are subjected to relative vibration between the duct 50 and the positive characteristic heating element 10, It is in a non-contact state and can be connected to a lead wire (not shown). The buffer material 63, which is an insulator and is a foam, is not limited to one, but may be two or more, or may be disposed around the main body 61. Of course, a rigid fixture may be provided between the duct 50 and the positive heating element 10.

FIG. 7 shows the molded resistor 21 of the positive heating element 20 shown in FIG. 3, and this will be described using the example of the hot air generating and supplying device used for heating the automobile shown in FIGS.
As shown in FIG. 7, the pair of electrodes 23 and 24 of the molded resistor 21 of the positive heating element 20 are provided on the molded resistor 21 by metal spraying, and the sprayed electrode film 23a and the electrode film 24a, the electrode terminal 23b, and the electrode terminal 24b are integrally provided.
One blower 70 is integrally joined to one end of the molding resistor 21 of the positive heating element 20 so as not to leak air. The blower 70 is attached to the duct 50 by means (not shown) using the main body 71. Strictly speaking, the output of the general-purpose blower 70 is a vortex, but the plurality of through holes 22 formed in the molding resistor 21 of the positive heating element 20 are parallel to the vortex center line of the blower 60. Then, while coming into contact with the peripheral surface of the through hole 22, the air is discharged from the through hole 22 on the electrode 13 side, and the wind is supplied into the vehicle through the air supply port 53.

  However, since the positive heating element 20 is attached to the duct 50 by the main body 71 of the blower 70, it is a so-called cantilever state as in the case of FIG. The material 73 provides positioning, sealing properties, and buffering properties with respect to the inner surface of the duct 50. As a result, the pair of electrodes 23 and 24 of the molding resistor 21 of the positive characteristic heating element 20 are also in a non-contact state with the duct 50.

  The molding resistors 11 and 21 of the first embodiment are a mixture mixed by blending aluminum powder 30 to 50 vol%, graphite powder 5 to 10 vol%, clay powder 30 to 50 vol%, wood powder 0 to 10 vol%, The whole is mixed by adding 15 to 25 vol% of water, molded by compression molding or extrusion molding, dried, sintered, and becomes a positive heating element 10, 20, which is sintered. The molded resistors 11 and 21 have a positive resistance temperature characteristic in which the resistance is low at room temperature, and the resistance rapidly increases as the temperature rises to a predetermined temperature.

  The positive heating elements 10 and 20 of the first embodiment obtained in this way are lightweight, harder than aluminum and resistant to wear, and have a mechanical strength higher than that formed by mixing raw materials. Increased and had high mechanical strength. In particular, the positive heat generating elements 10 and 20 of the first embodiment are not cracked even when heat is blown when the positive heat generating elements 10 and 20 are generating heat. Even when there was a thermal gradient (temperature distribution) at 10 and 20, it was not cracked during heat generation. Furthermore, it has been found that it is chemically strong such as acid.

  By the scanning electron microscope (SEM: secondary electron image) including the inventors' BSE (reflection electron microscope), the porous positive heating elements 10 and 20 of the first embodiment are distributed with open voids. It was found to be porous. Furthermore, the size of the voids was several μm to several tens of μm as a result of measurement with a gas adsorption type pore distribution measuring device. The size and porosity can be controlled.

As shown in FIG. 9A, the resistances of the positive heating elements 10 and 20 having positive resistance temperature characteristics are low at room temperature, and when a current is applied by applying a power supply, the temperature rises. The resistance value gradually decreases. However, when a certain temperature (Curie point temperature) Cu is reached, the temperature rises rapidly and the resistance suddenly increases.
When a voltage is supplied from a constant voltage power source, as shown in FIG. 9B, the current Is from the beginning tends to increase, becomes a peak current Ip at the resistance Rcu at the Curie point temperature Cu, and then gradually decreases. The constant current It becomes constant. When the constant current It becomes constant, the amount of heat generation is also constant, and the positive characteristic heating elements 10 and 20 at that time generate heat at a specific temperature.

At this time, the positive characteristic heating elements 10 and 20 rapidly rise to the Curie point temperature Cu, and the current overshoots to enter the control of the constant current It. However, when the elapsed time is viewed comprehensively, at a temperature equal to or higher than the Curie point temperature Cu, the resistance value change with respect to the temperature change becomes large, and the constant current It state is easily entered.
Therefore, by detecting the Curie point temperature Cu (peak current Ip), turning on the fans 60 and 70 at that time and performing constant speed rotation, air at a predetermined temperature can be quickly supplied into the vehicle.

Further, by turning on the blowers 60 and 70 from the beginning to the positive characteristic heating elements 10 and 20 and causing them to rotate at a constant speed, air at a predetermined temperature or higher can be quickly supplied into the vehicle. At this time, depending on the air blowing capability of the blowers 60 and 70, it may feel cold.
Then, by turning on the power of the blowers 60 and 70 from the beginning with respect to the positive characteristic heating elements 10 and 20 and causing them to rotate at a constant speed, air at a predetermined temperature or higher can be quickly supplied into the vehicle. At this time, depending on the air blowing capability of the blowers 60 and 70, it may feel cold.
Furthermore, by controlling the speed of the power supply of the blowers 60 and 70 from the beginning with respect to the positive characteristic heating elements 10 and 20, the air flow that does not feel cold is suppressed, so there is no case of feeling cold. Further, if the speed control is controlled in relation to the load current, the peak current Ip can be made a small increase as shown in FIG.

Usually, the hot air generating and supplying apparatus of the present embodiment is controlled by a circuit as shown in FIG.
The positive heating elements 10 and 20 are connected to the power source + B via the hot air generation switch SW and a current detection resistor r having a low resistance. At this time, the voltage at both ends of the current detection resistor r is detected by the A / D conversion circuit 81, converted into a digital value, and input to the microcomputer 83. The output of the microcomputer 83 is connected to the blowers 60 and 70 whose rotation is controlled via the driver 82.

Next, automatic control of the hot air generating and supplying apparatus of the present embodiment shown in FIG. 10 will be described with reference to FIG.
The program shown in FIG. 11 is called by a main program installed in the vehicle.
In step S11, it is determined whether or not the heating switch SW is turned on. When the heating switch SW is not turned on, this routine is exited. If it is confirmed in step S11 that the heating switch SW has been turned on, it is determined in step S12 whether or not the sampling time of 10 ms has elapsed. This sampling time is set to 1 to 500 ms. Waiting for the progress, current detection is performed in step S13. The voltage at both ends of the current detection resistor r is converted into a digital value by the A / D conversion circuit 81 and becomes an input to the microcomputer 83, and the data is stored in a memory built in the microcomputer 83 in step S14. At the time of this storage, the digital value output from the A / D conversion circuit 81 is converted from a voltage value to a current value.

In step S15, it is determined whether a predetermined number of data is stored in the memory storing the data. In this embodiment, the number of samplings is 10. When the predetermined number of data is not stored in the memory storing the data in step S15, it means that the elapsed time from turning on the heating switch SW is short, so the routine from step S11 is repeatedly executed. When a predetermined number of data is stored in the memory for storing data in step S15, it is determined whether or not the current value is maximum in step S16, and when the current value is not the maximum peak current Ip, The above routine is repeatedly executed.
When it is determined in step S16 that the current value is the maximum peak current Ip, the fans 60 and 70 are rotated at a constant speed in step S17. Repeatedly. When the heating switch SW is shut off in step S18, the blowers 60 and 70 are stopped in step S19, and this routine is exited.
In step S16, the determination that the current value is the maximum peak current Ip is made by starting the decrease in the current after 20 ms to 100 ms after the peak current Ip has passed.

As described above, the positive heating elements 10 and 20 according to the first embodiment include the mixture mainly composed of the aluminum powder 2, the graphite powder 3, and the square clay powder 4, that is, the sintered raw material mixture 7. Molding resistors 11 and 21 provided with a plurality of through-holes 12 and 22 and sintered by compression molding such as injection molding and press molding or extrusion molding extruded by an extruder, and molding resistors A pair of electrodes 13, 14, 23, 24 provided on 11, 21, and the molded resistors 11, 21 have a low resistance at room temperature, and a positive resistance whose resistance increases rapidly when it rises to a predetermined temperature Since it has temperature characteristics, a sintering raw material mixture 7 formed by mixing aluminum powder 2, graphite powder 3, and glazed clay powder 4 as clay powder for ceramics is molded by applying pressure. By mixing these sintering raw materials 7 becomes strong and dense solid state. Therefore, by sintering in this state, it is possible to obtain the positive strength heating elements 10 and 20 having high strength.
In addition, since the graphite powder 3 is mixed with the molding resistors 11 and 21, the graphite powder 3 adheres to the surface of the aluminum powder, and the aluminum powder 2 is covered with the graphite powder 3. In this case, even if the melting point of aluminum reaches 660.4 ° C., there is no sintering failure in which the aluminum melts and is ejected to the surface. The resistor has a positive characteristic, and the positive resistor generates heat when energized. As a result, the porous positive heating elements 10 and 20 have high mechanical strength and generate resistance heat when energized, and the porous positive heating elements 10 and 20 can increase to a specific temperature. Can be used as

In particular, the porous positive heating elements 10 and 20 obtained in this way have a high temperature rise rate by energization and a temperature fall rate by energization release for a large volume, and the heat generation temperature becomes constant depending on the energization amount. Therefore, resistance control in the manufacturing process is easy. That is, by selecting the particle shape and particle size distribution of the raw material, adjusting the blending amount, and adjusting the pressure of the molding resistor 11 and 21 to adjust the density of the molding resistors 11 and 21, In this case, by adjusting the sintering temperature to adjust the sintering density, the resistance value of the molded resistors 11 and 21 can be controlled to control the heat generation temperature due to energization. Also, by adjusting the resistance distribution of the positive heating elements 10 and 20 by adjusting the shape of the mold at the time of molding, adjusting the filling amount at the time of molding, adjusting the partial pressure at the time of molding, etc. A specific part of the resistors 11 and 21 can be heated to a specific temperature.
Therefore, the porous positive heating elements 10 and 20 of the present embodiment are suitable for use as resistance heating elements, and particularly suitable for the use of heating elements that are heated on the surface. In addition, it is chemically strong such as acid. In this way, the porous positive heating elements 10 and 20 have high mechanical strength, are electrically energized, and can be suitably used as resistance heating elements.

Here, the voids in the positive characteristic heating elements 10 and 20 are used as resistance heating elements when the voids in the molded resistors 11 and 21 are within a predetermined range as a result of repeated experiments by the inventors. In addition, it was found that sufficient strength and energization heat generation can be secured. That is, when the voids in the molded resistors 11 and 21 are small, the resistance value of the positive heating element is small and the heat generation due to energization is impaired. On the other hand, when there are too many voids in the molded resistors 11 and 21, the strength is insufficient in use as a resistance heating element, and the electrical conductivity is impaired.
The voids of the molded resistors 11 and 21 are measured by measuring the volume and weight of the formed dry pre-sintered molded body 8A and pre-sintered molded body 8B and impregnating with water. Then, after drying again, the weight was measured, and the change in the weight was replaced with the porosity. Moreover, the paraffin was impregnated in the place deaerated by the paraffin permeation apparatus (ULVAC DA-15D) and calculated from the change in weight. As a result, there was no significant difference. Therefore, the positive characteristic heating elements 10 and 20 having good heat dissipation efficiency can be obtained without generating heat and increasing the temperature above a predetermined temperature. And it is strong against heat shock, and even when a water droplet is dropped, it can be instantaneously converted into water vapor, so that humidity control can be performed simultaneously with temperature control.

  The plurality of through holes 12 and 22 provided for the molded resistor elements 11 and 21 of the positive heating elements 10 and 20 of the first embodiment are respectively circular in cross section, elliptical in cross section, elliptical in cross section, triangular in cross section, and cross section. Since either one of the quadrangular shape and the hexagonal cross section is used, the heat radiating surface is not constrained to a specific shape, so that the positive characteristic heating elements 10 and 20 with improved heat radiating effect can be obtained. Moreover, the form according to the speed of the flow of an airflow is employable by setting the fluid resistance of the some through-holes 12 and 22 to arbitrary values.

  The pair of electrodes 13, 14, 23, 24 provided on the molded resistors 11, 21 of the positive characteristic heating elements 10, 20 of the first embodiment are disposed at both ends in the length direction of the molded resistors 11, 21. Since it is formed, the pair of electrodes 13, 14, 23, 24 formed on both ends in the length direction of the molded resistors 11, 21 are connected from one end side to the other end side of the plurality of through holes 12, 22. Current flows, and the current path through which the current actually flows becomes a complicated path other than a straight line, so heat generation from the entire molded resistors 11 and 21 can be expected.

  A pair of electrodes 13, 14, 23, 24 provided to the molded resistors 11, 21 of the positive characteristic heating elements 10, 20 of the first embodiment is formed on the opposing surface side in the direction perpendicular to the length direction. Therefore, the pair of electrodes 13, 14, 23, 24 formed on the opposing surface side in the direction perpendicular to the length direction of the molded resistors 11, 21 are on both side surfaces of the plurality of through holes 12, 22. In principle, the heat is generated at the thinnest part of the cross-sectional shape of the molded resistors 11 and 21, so that the entire molded resistors 11 and 21 generate heat substantially uniformly. be able to. In particular, since a voltage is applied during a short distance of the molded resistor, a predetermined amount of heat can be generated at a low voltage.

  Since the pair of electrodes 12 and 22 provided for the molded resistors 11 and 21 of the positive heating elements 10 and 20 of the first embodiment are provided on the molded resistors 11 and 21 by thermal spraying, If the pair of electrodes 12 and 22 provided for the molding resistors 11 and 21 are embedded in the pre-sintered molded body 8 (8A and 8B), there is a possibility that they will melt due to the firing temperature during firing. . However, in the case of thermal spraying, it may be performed when the molded resistors 11 and 21 are completed, and thus the metal to be sprayed is not specified. Further, the molded resistors 11 and 21 take the form of a porous heating element, but can be connected to the terminal of the lead wire in a state where the surface area is utilized, and the heat generation of the electrodes 13, 14, 23, and 24 is extremely reduced. Can be reduced to a long life.

The molding resistors 11 and 21 of the positive heating elements 10 and 20 of the first embodiment are made of aluminum powder 30 to 50 vol%, graphite powder 5 to 10 vol%, clay powder 30 to 50 vol%, and metal silicon 5 as required. -15 vol%, and also a sintered raw material mixture 7 mixed by mixing with iron powder 0-5 vol% and wood powder 0-10 vol%, kneaded by adding water 15-25 vol% to the whole, compressed Since it is formed by forming or extruding and sintering the pre-sintered molded body 8 (8A, 8B) after drying, the following effects are produced.
That is, in the sintered raw material mixture 7, for example, when the content of the aluminum powder 2 is less than 30 vol%, the aluminum powder 2 is too small, and the electrical conductivity is impaired. On the other hand, when the content of the aluminum powder 2 exceeds 50 vol%, the portion of the aluminum powder 2 that is not covered with the graphite powder 3 increases, and this causes a sintering failure in which molten aluminum is ejected to the surface in the firing process. It tends to occur.
Here, metallic silicon 5-15 vol% and iron powder 0-5 vol% are used for determination of resistance value. In particular, 0-5 vol% of iron powder is useful for preventing oxidation. Moreover, although wood powder 0-10 vol% is used for forming a porous space | gap, since smoke comes out by combustion, the one which is as small as possible is desirable.

Further, for example, if the content of the graphite powder 3 is less than 5 vol%, the portion of the aluminum powder 2 that is not covered with the graphite powder 3 increases due to too little graphite powder 3, thereby melting in the firing process. It becomes easy to produce the sintering defect which the aluminum which ejected on the surface. On the other hand, when the content of the graphite powder 3 exceeds 10 vol%, the graphite powder 3 is too much and the strength and purity of the pre-sintered molded body 8 (8A, 8B) is lowered, and the resistance heating element of the porous heating element is used. In use, the strength and energization heat generation are insufficient.
And when the content of the clay mesh powder 4 as the clay powder for ceramics is, for example, less than 30 vol%, there is too little the clay clay powder 4 for ceramics, The resistance value becomes small, and the energization exothermicity becomes insufficient when the porous heating element is used as the resistance heating element. On the other hand, when the content of the ceramic clay powder 4 for ceramics exceeds 50 vol%, the clay powder for ceramics is too much and the conductivity is impaired.

Further, the wood powder 5 is obtained by finely pulverizing wood chips with a pulverizer, and it is preferable to use a whisker-like one. For example, by using whisker-like wood powder 5, raw materials such as aluminum powder 2, graphite powder 3, and mesh clay powder 4 are entangled in whisker-like gaps in the whisker, so that the filling property of the raw material is increased and molding is performed. What is generated by applying pressure in the process becomes strong and dense, but the pre-sintered molded body 8 (8A, 8B) can be obtained even if the wood powder 5 is not contained. Usually, it is desirable to add 0 to 10 vol%.
Therefore, according to the positive characteristic heating elements 10 and 20, it is sure to have high strength, energization heat generation, and high purity.
In addition, in the sintering raw material mixture 7, the content of the aluminum powder 2 is in the range of 40 vol% to 45 vol%, the content of the graphite powder 3 is in the range of 5 vol% to 10 vol%, and the mineral substance Since the content of the powder (ceramic clay powder 4 for ceramics) is in the range of 40 vol% to 45 vol%, it is possible to ensure high strength and purity and energization exotherm in the porous positive heating element more reliably. More preferable.

The hot air generating and supplying device of the second embodiment is formed by compressing or extruding a sintered raw material mixture 7 mainly composed of aluminum powder 2, graphite powder 3, and glazed clay powder 4, Sintered, the resistance is low at room temperature, and when the temperature rises to a predetermined temperature, the resistance increases rapidly. A positive characteristic heating element 10, 20 composed of a through hole 12, 22 and a pair of electrodes 13, 14, 23, 24 provided on the surfaces of the molded resistors 11, 21, and the positive characteristic heating element 10, 20 Are provided with blowers 60 and 70 for generating an air flow in the plurality of through holes 12 and 22, the aluminum powder 2, the graphite powder 3, and the ceramic clay powder 4 for ceramics are mixed. The resulting sintered raw material mixture 7 is molded by applying pressure. Accordingly, these sintered raw material mixture 7 becomes strong and dense solid state. Therefore, high strength positive heating elements 10 and 20 can be obtained by sintering in this state.
In addition, the graphite powder 3 is mixed with the molding resistors 11 and 21 of the positive heating elements 10 and 20, so that the graphite powder 3 adheres to the surface of the aluminum powder 2, and the aluminum powder 2 is applied to the graphite powder 3. Therefore, even when the melting point of aluminum (660.4 ° C.) is reached in the heating process, there is no sintering failure in which the aluminum melts and is ejected to the surface. Are combined to form molding resistors 11 and 21 having voids, and these molding resistors 11 and 21 generate heat when energized. As a result, the porous positive characteristic heating elements 10 and 20 have high mechanical strength and generate resistance heat when energized, and the porous positive characteristic heating elements 10 and 20 can be used as resistance heating elements.

  By the way, according to an experimental study by the present inventors, when firing without using graphite powder 3 such as graphite powder, aluminum (melting point: 660.4 ° C.) melts when the temperature in the temperature controlled electric furnace reaches 600 ° C. or higher. As a result, it was confirmed that the sintering failure occurred on the surface and an aluminum melt with a large number of depressions formed on the surface was produced, making it impossible to produce the above-described positive heating elements 10 and 20. ing. However, in the first embodiment, even if the temperature becomes higher than 700 ° C., the sintering failure that aluminum melts and is ejected to the surface does not occur.

In particular, the porous positive heating elements 10 and 20 obtained in this way have a high temperature rise rate by energization and a temperature fall rate by energization release for a large volume, and the heat generation temperature becomes constant depending on the energization amount. Therefore, resistance control in the manufacturing process is easy. That is, by selecting the particle shape and particle size distribution of the raw material, adjusting the blending amount, or adjusting the pressure during molding, and adjusting the density of the positive heating elements 10 and 20, Furthermore, by adjusting the sintering temperature to adjust the sintering density, it is possible to control the resistance value of the molding resistors 11 and 21 to control the heat generation temperature due to energization. Further, by adjusting the resistance distribution of the molding resistors 11 and 21 by adjusting the molding shape by the mold shape at the time of molding, adjusting the filling amount at the time of molding, or adjusting the partial pressure at the time of molding, etc. A specific part of the bodies 11 and 21 can be heated to a specific temperature.
Therefore, the porous positive heating elements 10 and 20 of the present invention are suitable for use as a resistance heating element, and particularly suitable for use as a heating element heated on the surface. In addition, it is chemically strong such as acid. In this way, the porous positive heating elements 10 and 20 have high mechanical strength, are electrically energized, and can be suitably used as resistance heating elements. And it is strong against heat shock, and even when a water droplet is dropped, it can be instantaneously converted into water vapor, so that humidity control can be performed simultaneously with temperature control.

Here, the gap between the molded resistors 11 and 21 of the positive characteristic heating elements 10 and 20 is a result of repeated experiments and researches by the present inventors. As a result, when the gap in the molded resistors 11 and 21 is within a predetermined range, It has been found that even if it is used as a resistance heating element, sufficient strength and energization heat generation can be secured. That is, if the gaps between the molded resistors 11 and 21 are small, the resistance values of the positive characteristic heating elements 10 and 20 are small, and the heat generation due to energization is impaired. On the other hand, if there are too many voids in the molded resistors 11 and 21, the strength is insufficient in use as a resistance heating element, and the electrical conductivity is impaired.
Further, by the blowers 60 and 70 that generate an air flow in the plurality of through holes provided in the molding resistors 11 and 21 of the positive heating elements 10 and 20, the amount of heat radiated from the positive heating elements 10 and 20 is changed by the air flow. It can be moved to the destination location. Therefore, the amount of heat can be easily moved.
Accordingly, the positive characteristic heating elements 10 and 20 having good heat dissipation efficiency and the positive characteristic heating elements 10 and 20 generate heat and generate hot air without generating a temperature exceeding a predetermined temperature. The hot air can be supplied.

  The plurality of through holes 12 and 22 provided in the molding resistors 11 and 21 of the hot air generation and supply device of the second embodiment are respectively circular in cross section, elliptical in cross section, elliptical in cross section, triangular in cross section, rectangular in cross section, and in cross section. Since any one of the squares is used, the heat radiating surface is not constrained to a specific shape, so that the positive characteristic heating elements 10 and 20 with improved heat radiating effects can be obtained. Moreover, the form according to the speed of the flow of an airflow is employable by setting the fluid resistance of the some through-holes 12 and 22 to arbitrary values.

Since the pair of electrodes 12 and 22 provided on the molding resistors 11 and 21 of the hot air generation and supply device of the second embodiment are formed at both ends in the length direction of the molding resistors 11 and 21. The pair of electrodes 13, 14, 23, 24 formed on both ends of the positive heating elements 10, 20 in the length direction allows current to flow from one end side to the other end side of the plurality of through holes 12, 22. Since the energization path through which the current is actually energized becomes a complicated path other than a straight line, heat generation from the positive characteristic heating elements 10 and 20 can be expected.
Therefore, since the heat generating elements 10 and 20 generate heat in two-dimensional and three-dimensional spaces, the positive characteristic heating elements 10 and 20 can be configured according to their use.

  The pair of electrodes 13, 14, 23, 24 provided on the molding resistors 11, 21 of the hot air generating / supplying device according to the second embodiment is formed on the opposing surface side in the direction perpendicular to the length direction. Thus, the pair of electrodes 13, 14, 23, 24 formed on the opposing surfaces in the direction perpendicular to the length direction of the molded resistors 11, 21 apply a voltage to both side surfaces of the plurality of through holes 12, 22. In principle, since the heat is generated at the thinnest portion of the cross-sectional shape of the molded resistors 11 and 21, the entire molded resistors 11 and 21 can generate heat almost uniformly. Therefore, by setting the fluid resistance of the plurality of through holes 12 and 22 to an arbitrary value, the temperature distribution of the vertical cross section with respect to the air flow can be made substantially uniform. In particular, since a voltage is applied during a short distance of the molded resistor, a predetermined amount of heat can be generated at a low voltage.

  Since one or more blowers 60 and 70 for generating an air flow in the plurality of through holes 12 and 22 provided in the molding resistors 11 and 21 of the hot air generation and supply device of the second embodiment are provided. The direction of the wind guided by the fins receiving the wind of the blowers 60 and 70 can be set, and the air flow can be freely selected in the diffusion direction or the parallel direction.

  Since the pair of electrodes 13, 14, 23, 24 provided on the molding resistors 11, 21 of the hot air generating / supplying device of the second embodiment are provided on the molding resistors 11, 21 by spraying. The pair of electrodes 13, 14, 23, 24 provided on the molding resistors 11, 21 may be melted at the firing temperature during firing when embedded in the pre-sintered molded body 8. Is performed when the molded resistors 11 and 21 are completed, and the metal to be sprayed is not specified. The molded resistors 11 and 21 take the form of porous positive heating elements 10 and 20, but can be connected to the terminals of the lead wires in a state where the large surface area is utilized. Heat generation of the electrodes 13, 14, 23, and 24 can be extremely reduced, resulting in a long life.

Molding resistors 11 and 21 of the hot air generation and supply device of the second embodiment have aluminum powder 2 of 30 to 50 vol%, graphite powder 3 of 5 to 10 vol%, Sasame clay powder 4 of 30 to 50 vol%, wood Sintering raw material mixture 7 in which powder 5 is mixed by blending with 0 to 10% by volume, water 6 is added to and kneaded with 15 to 25% by volume, and the powder 5 is molded by compression molding or extrusion molding and sintered. Since the pre-molded body 8 is dried and sintered, the positive heating elements 10 and 20 surely have high strength and energization heat generation and high purity.
That is, in the sintering raw material mixture 7, when the content of the aluminum powder 2 is less than 30 vol%, the aluminum powder 2 is too small and the conductivity is impaired. On the other hand, when the content of the aluminum powder 2 exceeds 50 vol%, the portion of the aluminum powder 2 that is not covered with the graphite powder 3 increases, and this causes a sintering failure in which molten aluminum is ejected to the surface in the firing process. It tends to occur.
Further, if the content of the graphite powder 3 is less than 5 vol%, the portion of the aluminum powder 2 that is not covered with the graphite powder 3 increases because the graphite powder 3 is too small. Sintering failure that occurs on the surface tends to occur. On the other hand, when the content of the graphite powder exceeds 10 vol%, the graphite powder 3 is too much and the strength and purity of the pre-sintered molded body 8 (8A, 8B) is lowered, and the porous heating element is used as a resistance heating element. In use, the strength and the heat generation are insufficient.

And if the content of the ceramic clay powder 4 for ceramics is less than 30 vol%, the amount of the plastic clay powder 4 as the clay powder for ceramics is too small, and the resistance values of the molded resistors 11 and 21 obtained are As a result, the current-generating heat generation becomes insufficient when the porous heating element is used as a resistance heating element. On the other hand, if the content of the ceramic clay powder 4 for ceramics exceeds 50 vol%, the ceramic clay powder 4 for ceramics is too much and the electrical conductivity is impaired.
Further, the wood powder 5 is obtained by finely pulverizing wood chips with a pulverizer, and it is preferable to use a whisker-like one. By using whisker-like wood powder, raw materials such as aluminum powder, graphite powder, and clay-like clay powder get entangled in whisker-like gaps in the whisker. The resulting product is strong and dense, but the molded resistors 11 and 21 can be obtained even if the wood powder 5 is not contained. Usually, it is desirable to add 0 to 10 vol%, and it is desirable to reduce the amount so that smoke is not generated as much as possible.
Therefore, according to the positive-characteristic heating elements 10 and 20, it is sure to have high strength, energization heat generation, and high purity.
In addition, in the sintering raw material mixture 7, the content of the aluminum powder 2 is in the range of 40 vol% to 45 vol%, the content of the graphite powder 3 is in the range of 5 vol% to 10 vol%, and the mineral substance It is more preferable because the content of the powder (ceramic clay powder 4 for ceramics) is in the range of 40 vol% to 45 vol%, so that high strength and purity as well as energization exotherm can be ensured in the porous heating element. .

  The blowers 60 and 70 that generate an air flow in the plurality of through holes 12 and 22 provided in the molding resistors 11 and 21 of the hot air generation and supply device of the second embodiment are configured to supply power to the positive heating elements 10 and 20. Since the air flow is generated by the constant speed rotation of the blowers 60 and 70 simultaneously with the supply, the voltage is applied under the amount of heat radiated from the positive characteristic heating elements 10 and 20. Although it takes a little time to reach the inherent temperature rise of 20, the human body does not feel the coolness of the air blower even at the beginning of energization, and the air temperature of the air blowers 60 and 70 gradually increases. As the temperature rises, temperature control without a sense of incongruity becomes possible. In particular, as shown in FIG. 9C, in the relationship between time and air volume, even if a slight delay Δt occurs in the detection of the peak value Ip, a person does not feel it sharply.

  The blowers 60 and 70 that generate an air flow in the plurality of through holes 12 and 22 provided in the molding resistors 11 and 21 of the hot air generation and supply device according to the second embodiment are the positive characteristics of the positive heating elements 10 and 20. According to the resistance temperature characteristic, the positive characteristic heating elements 10 and 20 are detected to rise to a predetermined temperature by the peak value Ip of the energizing current, and after the peak value Ip is detected, the fans 60 and 70 are rotated at a constant speed. Since warm air is generated, when the energization of the positive characteristic heating elements 10 and 20 is started, the blowers 60 and 70 are driven at a low speed or the positive characteristic heating elements 10 and 20 are driven. At the beginning of energization, the fans 60 and 70 are driven at high speed, and thereafter, the peak value Ip of the energization current means that the temperature at which the positive characteristic heating elements 10 and 20 can be steadily operated is exceeded. Air blow at constant speed 60 and 70 are operated, so that temperature control can be performed by the blowers 60 and 70 in accordance with the purpose from the beginning of energization, and the temperature of the wind of the blowers 60 and 70 gradually increases, so that temperature control without a sense of incongruity is possible. Become.

  The blowers 60 and 70 for generating an air flow in the plurality of through holes 12 and 22 provided for the molding resistors 11 and 21 of the hot air generation and supply apparatus of the second embodiment are the positive characteristic heating elements 10 and 20. In accordance with the positive resistance temperature characteristic, it is detected from the peak value Ip of the energizing current that the molded resistors 11 and 21 have risen to a predetermined temperature, and the blowers 60 and 70 are energized until the peak value Ip is detected. Since the air flow is generated by performing constant speed rotation of the blowers 60 and 70 after the peak value Ip is detected, the peak of the current when the positive heating elements 10 and 20 rise to a predetermined temperature. Based on the value Ip, it is determined that the positive characteristic heating elements 10 and 20 have reached a predetermined temperature, and thereafter, the start of supply of the predetermined hot air is recognized by operating the blowers 60 and 70 at a steady rotation. It is possible . Therefore, the coolness of the wind of the blowers 60 and 70 is not felt at the beginning of energization.

12 and 13 show a hot air generation and supply device according to a modification of the embodiment shown in FIG.
Note that the same symbols and the same reference numerals as those in the second embodiment mean functional parts that are the same as or correspond to those in the second embodiment, and thus detailed description thereof is omitted here.
The microcomputer 83 uses the circuit shown in FIG. That is, in this embodiment, only the function of humidity control is added.
The output of the humidity sensor 91 on the intake side of the indoor air of the blower 60 is input to the microcomputer 83. Further, the output of a water level sensor 94 that detects the water level of the water tank 93 is input. Then, it is output from the microcomputer 83 to the blower 60 via the driver 82. Further, it is output to the pump 96 via the driver 95. In addition, the opening / closing (turning) angle of the switching valve 54 is controlled from the microcomputer 83 via the driver 88.

The pump 96 draws water from the water tank 93 by supplying electric power and supplies the water to the ceramic drip pipe 92 so as to drip the water. The feeding is about 0.1 to 0.5 cc in 60 seconds. The reason why the dropping pipe 92 made of ceramic as an insulator is inserted into the positive characteristic heating element 20 is to prevent the dropping pipe 92 from being deformed by the heat generated by the positive heating element 20.
The pump 96 is driven for T _ON seconds and is in a pause state for T _OFF seconds, for example, an intermittent operation in which the pause state is 30 to 180 seconds.

The humidity control program shown in FIG. 13 is called by the main program installed in the vehicle.
In step S21, it is determined whether the switching valve 54 is opened on the inside of the vehicle and the outside of the vehicle is closed. When the switching valve 54 is fully opened on the outside of the vehicle, this routine is not entered without entering the humidity control mode. escape. When the switching valve 54 is open on the inside of the vehicle, it is checked in step S22 whether the blower 60 is operating. If not, this routine is exited.

Further, when the output of the humidity sensor 91 is observed at step S23 and the humidity is above a predetermined humidity, when the output of the water level sensor 94 for detecting the water level of the water tank 93 is below a predetermined depth at step S24, Leave this routine. However, when the output of the humidity sensor 91 is lower than the predetermined humidity in step S23, and the output of the water level sensor 94 for detecting the water level of the water tank 93 is determined to exceed the predetermined depth in step S24. In step S25 and step S26, the pump 96 is driven for T _ON seconds. When driving for T _ON seconds is completed, the pump 96 is stopped for T _OFF seconds in steps S27 and S28, and the drive stop time for T _OFF seconds is set. When the time has elapsed, the process returns to the routine processing from step S21.

That is, in the routine from step S21 to step S24, when the switching valve 54 is opened inside the vehicle at step S21, when the blower 60 is operating at step S22, the humidity sensor is below a predetermined humidity at step S23. In step S24, when all the conditions when the water level of the water tank 93 is deeper than the predetermined depth are satisfied at the same time, an intermittent operation in which the pump 96 is driven for a predetermined time is performed.
In this way, the porous positive heating elements 10 and 20 can function not only as a temperature control heat source but also as a humidification control humidifier. In particular, since the porous positive heating elements 10 and 20 heat the entire water droplets at the porous portion, the water molecules to be vaporized become fine and the indoor environment can be improved.

Here, an application field (use application) of the porous positive heat generating elements 10 and 20 of the first embodiment will be described.
As described above, the porous positive characteristic heating elements 10 and 20 of Embodiment 1 have electrical conductivity, high electrical resistance, and positive positive heat generation characteristics, so that they can be used as resistance heating elements.
More specifically, for example, it can be used as various heat sources such as an electric heating heating element, an electric heater, an electric water heater, and floor heating.
In particular, since the porous positive heating elements 10 and 20 of the first embodiment generate heat from the entire surface, they can be used as planar heating elements. Of course, use as a cooker for electromagnetic induction heating (IH) is also possible.
In addition, in the use as various heating elements, the porous positive heating elements 10 and 20 as resistance heating elements have low heat conduction as described above, and the heating temperature can be kept constant depending on the amount of current flow. It can be used in a wide temperature range from low temperature to high temperature, and temperature control is easy.

  In addition to the resistance heating type, as described above, the rate of temperature rise by energization and the rate of temperature decrease by energization release are faster than the size of the volume. However, it can save power and has high safety. In particular, in the use as an electric heater or the like, the use of the porous positive characteristic heating elements 10 and 20 as a direct resistance heating element makes the thermal efficiency extremely higher than that of a conventional indirect resistance heating type electric heater or the like. High and power saving. Furthermore, while the conventional sheet heating element is a heater wire coated with metal or ceramic and has low thermal efficiency, the use of the porous positive heating elements 10 and 20 as direct resistance heating elements makes the thermal efficiency low. Is extremely high and can save power. Moreover, the characteristic that the heating rate of the porous positive characteristic heating elements 10 and 20 and the temperature decreasing rate due to the release of energization are fast are particularly promising as heating elements for quenching annealing and industrial product heating.

Furthermore, as described above, the manufacturing cost can be reduced, so that the cost can be reduced compared to various conventional heating elements, and the light weight and the high mechanical strength can reduce the size. is there.
In addition, according to the experimental study by the present inventors, the porous positive heating elements 10 and 20 of the first embodiment do not change color (red heat) until the temperature exceeds 550 ° C., and the resistance changes with time. It is so small that it cannot be confirmed, that there is no change in strength or electrical characteristics even when immersed in concentrated hydrochloric acid solution, and that even if a water drop is dropped under an exothermic state of 800 ° C., it does not break. Since it has been confirmed, is not easily burned out, and is chemically stable, it can be used particularly suitably for specific applications as the above-mentioned electrical material, and a long life as a product can also be expected.

In addition, according to the porous positive heating elements 10 and 20 of the first embodiment, the sintering temperature is further adjusted by adjusting the particle shape and amount of the raw material, adjusting the pressure during molding, and the like. Since the resistance value of the positive characteristic heating elements 10 and 20 can be controlled by the above, etc., the heating temperature corresponding to each application can be controlled as the resistance heating element.
Furthermore, it is possible to control the resistance distribution in the molding resistors 11 and 21 by adjusting the partial pressure at the time of molding, adjusting the molding shape by the mold shape at the time of molding, adjusting the filling amount at the time of molding, etc. Therefore, the porous positive heating elements 10 and 20 as resistance heating elements can be set to control the temperature distribution due to heat generation. In addition, utilizing the fact that the temperature distribution can be controlled by this heat generation, for example, by using the porous positive heating elements 10 and 20 as heating elements for food processing such as baked confectionery, desired foods can be obtained. The part can be burnt.

  In addition, when water was applied to or sprayed on the porous positive characteristic heating elements 10 and 20 in a heat generation state by energization, warm water vapor was generated from the positive characteristic heating elements 10 and 20. From this, the positive characteristic heating elements 10 and 20 of the first embodiment can be used as, for example, a humidifier, a water vapor generator, and the like. Further, for example, in the porous positive heating elements 10 and 20 used as an electric heating heating element or the like, by blowing water on the other surface while blowing air on one surface, Since the hot water vapor can be generated from the positive heating elements 10 and 20, it can be used as an electric heating heating element that can be expected to prevent overdrying. Incidentally, the generation of fine water vapor from the porous positive heating elements 10 and 20 by watering or the like is due to the positive heating elements 10 and 20 being porous and air permeable (having continuous pores). It seems to be. Further, by utilizing this porous and breathable property, it can be expected to be used as a heating element for distillation such as a hot air generator, a drying device, or alcohol.

According to the experimental study of the present inventors, the inventors have also pursued a positive characteristic heating element having a positive temperature coefficient having the same characteristics as the PTC thermistor.
The molding resistors 11 and 21 of the first embodiment are a mixture mixed by blending aluminum powder 30 to 50 vol%, graphite powder 5 to 10 vol%, clay powder 30 to 50 vol%, wood powder 0 to 10 vol%, The whole is mixed by adding 15 to 25 vol% of water, molded by compression molding or extrusion molding, dried, sintered, and becomes a positive heating element 10, 20, which is sintered. The molded resistors 11 and 21 have a positive resistance temperature characteristic in which the resistance is low at room temperature, and the resistance rapidly increases as the temperature rises to a predetermined temperature. However, by making a mixture of 5-10 vol% metal silicon and 0-10 vol% iron powder, the resistance is low at room temperature, and the resistance temperature characteristic increases rapidly when the temperature rises to a predetermined temperature. changed.

For example, when 5 to 10 vol% of metallic silicon is mixed, it is possible to ensure energization stability. Moreover, when iron powder 0-10 vol% is mixed, since iron powder functions as a resistor by oxidation, it can be used for resistance value control. However, since metal silicon and iron powder have the property as a conductor, the property as a positive characteristic heating element having a positive temperature coefficient having the same characteristics as the PTC thermistor is deteriorated. That is, it approaches a function as a simple heating element. In particular, when the compounding amount of 5-10 vol% of metallic silicon and 0-5 vol% of iron powder is increased, the properties as a conductor are enhanced.
That is, the molding resistors 11 and 21 of the first embodiment are made of aluminum powder 30 to 50 vol%, graphite powder 5 to 10 vol%, clay powder 30 to 50 vol%, wood powder 0 to 10 vol%, and metal silicon 5 to 10 vol%. , A mixture mixed by mixing with iron powder 0-5 vol%, knead added to the whole with 15-25 vol% water, molded by compression molding or extrusion, dried, sintered, A positive heating element having a positive temperature coefficient having the same characteristics as the PTC thermistor can be obtained.

Further, according to the experimental study by the present inventors, it has been confirmed that the positive characteristic heating elements 10 and 20 of the first embodiment generate far infrared rays. 10 and 20 can also be expected to have a heat transfer effect by far infrared rays as heating elements.
Various types of such ceramic far-infrared radiation materials are known along with their emissivity and radiation characteristics. For example, alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), titania (TiO ₂ ), silica (SiO ₂ ), zircon (ZrSiO ₄ ), magnesia (MgO), yttria (Y ₂ O ₃ ), cordierite ( 2MgO · 2Al ₂ O ₃ · 5SiO ₂ ), β-spodumene (Li ₂ O · Al ₂ O ₃ · 4SiO ₂ ), mullite (Al ₂ O ₃ · 3SiO ₂ ), aluminum titanate (Al ₂ O ₃ · TiO ₂ ) These are generally white in color.

In addition to the above-described white materials, ceramic far-infrared radiation materials include ceramic far-infrared radiation materials having high emissivity in a colored all-infrared region. Examples of such colored ceramic materials include copper oxide (Cu ₂ O, CuO), cobalt oxide (CoO, Co ₃ O ₄ ), nickel oxide (NiO), manganese oxide (MnO ₂ ), iron oxide ( Transition metal oxides such as Fe ₂ O ₃ ), chromium oxide (Cr ₂ O ₃ ), tin oxide (SnO ₂ ), silicon carbide (SiC), zirconium carbide (ZrC), tantalum carbide (TaC), etc. Examples thereof include carbides, and many of these are generally used as ceramic pigments. In addition, high efficiency infrared radiation can be obtained by combining two or more of these, for example, MnO ₂ —Fe ₂ O ₃ —CuO—CoO, CoO—Fe ₂ O ₃ —Cr ₂ O ₃ —MnO _2, etc. The integrated fired product is called a high-efficiency infrared radiator, exhibits a black color, and has an infrared radiation characteristic close to that of a “black body”.

Thus, the positive heating elements 10 and 20 of the first embodiment include the aluminum powder 2, the graphite powder 3 as a graphite powder that does not melt at a temperature lower than the melting point of aluminum, and the clay powder for ceramics. Sintered clay powder 4 and a mixture of these aluminum powder 2, graphite powder 3, tracer clay powder 4 and wood powder 5 with water and / or binder 6 in an amount that does not move due to the difference in specific gravity. The raw material mixture 7 is molded by applying pressure at room temperature, sintered at a temperature in the range of 900 ° C. to 1100 ° C. and having voids in the range of 5% to 50%, and generates positive heat when energized. The bodies 10 and 20 are formed.
Therefore, according to the positive characteristic heating elements 10 and 20 of the first embodiment, the mechanical strength is high, and resistance heat is generated by energization, and it can be used as a resistance heating element.

In particular, the porous positive heat generating elements 10 and 20 of the first embodiment have a high temperature rising rate by energization and a temperature decreasing rate by energization release for a large volume, and the heat generation temperature is constant depending on the amount of energization.
Furthermore, resistance control in the manufacturing process is easy. That is, the density of the pre-sintered molded body 8 (8A, 8B) is adjusted by selecting the particle shape and particle size distribution of the raw material, adjusting the blending amount, and adjusting the pressure during molding. Further, by adjusting the sintering temperature by adjusting the sintering temperature, the resistance value of the molding resistors 11 and 21 can be controlled to control the heat generation temperature due to energization. Also, by adjusting the resistance distribution of the molding resistors 11 and 21 by adjusting the molding shape by the mold shape at the time of molding, adjusting the filling amount at the time of molding, adjusting the partial pressure at the time of molding, etc., positive characteristics Different heat generation temperatures can be set in the heat generating elements 10 and 20, and specific portions of the porous positive characteristic heat generating elements 10 and 20 can be heated to specific temperatures. Therefore, it is suitable for the use of a heating element or the like as a resistance heating element.

Furthermore, according to the positive heating elements 10 and 20 of the first embodiment, each raw material is an easily available and inexpensive material, and is not manufactured under special conditions such as non-oxidizing conditions. Manufacturing costs can be reduced.
In this way, the positive heating elements 10 and 20 have high mechanical strength and are chemically strong such as acid, have energization heat generation, and can be used as resistance heating elements. In addition, it has high mechanical strength and is electrically energized and can be used as a resistance heating element.

  Moreover, in the said Embodiment 1, although graphite powder 3 was used as carbon powder, when implementing this invention, as graphite powder 3, it does not melt at the temperature lower than the melting point of aluminum powder 2, It is sufficient that the aluminum powder 2 is covered as long as it can suppress a sintering failure in which aluminum is ejected to the surface and is not sintered in the firing process. In addition to the graphite powder 3, for example, carbon black, carbon fiber And activated carbon. However, since the graphite powder 3 has a high melting point and easily adheres to the surface of the aluminum powder 2 (easy to be entangled), it is possible to reliably suppress the sintering failure in which aluminum is ejected to the surface during the firing process, and to stabilize the heating element Performance such as improved strength and heat generation can be ensured. For this reason, carbon powder is suitable as the graphite powder 3.

In Embodiment 1 described above, wood flour 5 is used as a raw material, but this is not an essential component for the present invention. However, when the wood powder 5 is mixed, the strength of molding and solidification can be improved, and the strength of the porous positive characteristic heating elements 10 and 20 can be improved. Since the wood powder 5 is burned away and becomes voids in the firing process, the porosity in the porous positive heating elements 10 and 20 can be easily controlled by adjusting the blending amount. The resistance values of the characteristic heating elements 10 and 20 can be easily controlled. Further, even when water droplets or the like were dropped on the heated positive heating elements 10 and 20, no change in the life occurred due to such a heat shock.
Note that the numerical values given in the embodiments of the present invention are not all critical values, and certain numerical values indicate preferred values suitable for implementation, so even if the numerical values are slightly changed. The implementation is not denied.

2 Aluminum powder 3 Graphite powder (graphite powder)
4 Clay powder (Sasame clay powder)
5 Wood powder 6 Water / binder 7 Sintering raw material mixture 8, 8A, 8B Pre-sintered molded body 10, 20 Positive characteristic heating element 11, 21 Molded resistor 13, 14 Electrode 13a, 14a Electrode film 13b, 14b Electrode terminal 60 , 70 Blower

Claims (19)

A molding resistor in which a mixture of aluminum powder, graphite powder, and clay powder as main materials is formed by compression molding or extrusion, and a plurality of through-holes are provided therein and sintered.
Comprising an electrode provided on the molded resistor;
The molded resistor has a positive resistance-temperature characteristic in which the resistance is low at room temperature and the resistance rapidly increases when the resistance increases to a predetermined temperature.   2. The positive heating element according to claim 1, wherein each of the plurality of through holes is one or more of a circular cross section, an elliptical cross section, an elliptical cross section, a triangular triangle, a rectangular cross section, and a hexagonal cross section. .   3. The positive heating element according to claim 1, wherein the electrodes are formed on both ends in the length direction of the molded resistor.   3. The positive heating element according to claim 1, wherein the electrode is formed on an opposing surface side in a direction perpendicular to the length direction. 4.   The positive electrode heating element corresponding to any one of claims 1 to 4, wherein the electrode is provided on the molding resistor by metal spraying.   The molding resistor is a mixture of aluminum powder 30 to 50 vol%, graphite powder 5 to 10 vol%, clay powder 30 to 50 vol%, and wood powder 0 to 10 vol%. 6. Positive heat generation corresponding to any one of claims 1 to 5, characterized in that it is kneaded by adding ~ 25 vol%, molded by compression or extrusion, dried and then sintered. body.   Furthermore, it was set as the mixture which mixed 5-10 vol% of metallic silicon and 0-10 vol% of iron powder, The positive characteristic heat generating body applicable to Claim 6 characterized by the above-mentioned. A mixture mainly composed of aluminum powder, graphite powder, and clay powder is provided with a plurality of through-holes together with outer shape molding by compression molding or extrusion molding, and is sintered. A molded resistor having a positive resistance temperature characteristic in which resistance rapidly increases when the temperature rises, an electrode provided on the molded resistor,
An apparatus for generating and supplying hot air, comprising: a blower that forms an air flow in the plurality of through holes provided for the molding resistor.   9. The hot air generation supply according to claim 8, wherein each of the plurality of through holes has one or more of a circular cross section, an elliptical cross section, an elliptical cross section, a triangular triangle, a rectangular cross section, and a hexagonal cross section. apparatus.   The hot air generating and supplying device according to claim 8 or 9, wherein the electrodes are formed on both ends in the length direction of the molded resistor.   The hot air generating / supplying device according to claim 8 or 9, wherein the electrode is formed on an opposing surface side in a direction perpendicular to the length direction.   The hot air generation and supply device according to any one of claims 8 to 11, wherein at least one blower for generating an air flow in the plurality of through holes is disposed.   The hot air generating and supplying device according to any one of claims 8 to 12, wherein the electrode is provided on the molding resistor by thermal spraying of metal.   The molding resistor is a mixture of aluminum powder 30 to 50 vol%, graphite powder 5 to 10 vol%, clay powder 30 to 50 vol%, and wood powder 0 to 10 vol%. The hot air generation according to any one of claims 8 to 13, wherein ~ 25 vol% is added and kneaded, molded by compression molding or extrusion molding, dried and then sintered. Feeding device.   Furthermore, it was set as the mixture which mixed 5-10 vol% of metallic silicon and 0-10 vol% of iron powder, The warm air generation supply apparatus applicable to Claim 14 characterized by the above-mentioned.   The blower that generates an air flow in the plurality of through holes provided in the molded resistor generates hot air by starting constant speed rotation of the blower simultaneously with the supply of electric power to the positive characteristic heating element. The hot air generating and supplying device corresponding to any one of claims 8 to 14.   The blower for generating an air flow in the plurality of through holes provided in the molding resistor controls the rotation speed according to the positive resistance temperature characteristic of the positive characteristic heating element, and the positive characteristic heating element is set to a predetermined temperature. The rising is detected by the peak value of the energization current, and after the peak value is detected, warm air is generated by the constant speed rotation of the blower. A warm air generator / applicable device.   The blower that generates an air flow in the plurality of through holes provided in the molded resistor is energized according to the positive resistance temperature characteristic of the positive characteristic heating element that the positive characteristic heating element has risen to a predetermined temperature. It detects by the peak value of electric current, does not energize the blower until the peak value is detected, and generates warm air by rotating the blower at a constant speed after the peak value is detected. The hot air generating and supplying device corresponding to any one of claims 8 to 14.   The water resistance is dropped on the molding resistor of the positive characteristic heating element, and the humidity is put on the air flow. A warm air generator / applicable device.

Images