JP3368615B2 - Heating equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating application such as an electric warmer, an electric floor heating, a panel heater, etc.
The present invention relates to a heating device useful for various purposes such as freeze prevention, and particularly to the structure of this heating element.

[0002]

2. Description of the Related Art As a heat source for a conventional heating device of this type,
There is a positive resistance temperature coefficient heating element, which is excellent in safety and rapid heating and has been put to practical use. The positive resistance temperature coefficient heating element is classified into a ceramic heating element containing barium titanate as a main component and a carbon-resin heating element containing a crystalline polymer and carbon black as a main component. The ceramic heating element has better thermal conductivity of the resistor itself, and it is easy to achieve higher output, but in terms of workability, there is no choice but to restrict the size and shape considerably, In a long heating element, etc., it is unavoidable to dispose a large number of these small elements, which not only complicates the connection for power supply, but also is not flexible and easily cracked, and the thermal element etc. It had the property of being difficult to bind to.

As the ceramic heating element, a honeycomb heater in which a large number of holes are formed in the positive characteristic thermistor element body itself, or a harmonica shape in which a large number of flat plate-shaped positive characteristic thermistor element bodies are arranged at regular intervals There are heaters, and heaters in which corrugated fins are joined. On the other hand, a carbon-resin-based heating element has a large area, is excellent in workability in a long length, is flexible, and is easy to mount the heating element, but has a high output in order to prevent hot zones from occurring. There was a limit to the conversion. However, especially when a high power density or high temperature is required, it is essential to make the temperature distribution in the direction between the pair of electrodes always good in order to make the temperature distribution of the heating element itself uniform. As a solution, Shokoku Sho 62-5
As shown in Japanese Patent Publication No. 9415 and FIG. 13, a method has been taken in which a distance between a pair of electrodes is close to each other. FIG.
In the above, reference numerals 1 and 2 are a pair of electrodes provided close to each other, and a resistor 3 formed by mixing and dispersing conductive fine powder in a crystalline polymer is arranged between them to obtain a high output positive resistance. The possibility of developing a temperature coefficient heating element has been found, and it is expected to be widely applied to this type of heating device. In addition, 4 and 5 are exterior materials.

[0004]

However, such a conventional heating device is self-controlled to an appropriate temperature by the positive resistance temperature characteristic, and exhibits excellent effects such as safety and rapid heating. However, especially in the case of a high-output, high-temperature heating device, the resistance in the low temperature range has an extremely low resistance value, and the rush current at the start of energization of the heating device is large from a practical point of view. However, this often imposes great restrictions on the above, and often causes problems in application development. In fact, in order to keep the inrush current at the lowest operating temperature of the heating device below a certain maximum allowable current value, it was often the case that the heating device was limited to small-area heating devices, low-temperature heating devices, etc. . For this reason, a method of dividing the heating element portion into a plurality of portions and sequentially energizing them at time intervals, a method of starting energization after preheating with another heat source, etc. was taken and there was a temporary effect. , Wiring connection becomes complicated, other heat source is required, etc.
It was difficult to put to practical use.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a heating element structure of a highly safe heating device in which an inrush current is suppressed.

[0006]

In order to achieve the above object, the heating apparatus of the present invention comprises an organic positive temperature coefficient resistor having a conductive fine powder and a crystalline polymer, and an electrical resistor for the resistor. It has negative resistance temperature characteristics in the low temperature range and is connected in series with a positive resistance temperature characteristic in the high temperature range.
A positive and negative characteristic resistor that turns into a positive and negative characteristic, the organic resistor and the positive and negative characteristic resistor are thermally coupled by a heat conductor or air flow, and the organic resistor and the
The formation ratio of the positive and negative characteristic resistors is the same as that of the organic resistor.
It is mainly used, and the
Both positive and negative characteristic resistors remain in the low temperature range where they show negative characteristics, and the temperature range is higher than the temperature of the organic resistor when the heating device is energized and lower than the melting point of the organic resistor material. In, the combined resistance of the organic resistor and the negative characteristic resistor has a positive temperature coefficient of resistance.

As a specific constitution of the above means, an organic positive temperature coefficient of resistance temperature coefficient consisting of conductive fine powder and a crystalline polymer and a low temperature region electrically connected in series to this resistance are used. Cue with negative resistance temperature characteristic
Shows positive resistance-temperature characteristics in the high temperature range near the Lee temperature
And a positive negative both resistance-temperature coefficient resistor to barium titanate, the resistor of the barium titanate has a high Curie temperature than the melting point of the crystalline polymer of the resistor of the organic, the The organic resistor and the barium titanate resistor are thermally coupled with each other by a heat conductor or blown air.

Further, the positive and negative characteristic resistors or the barium titanate type resistor can be thermally coupled with the overheat preventing function.

[0009]

The function of this technical means is as follows.
Organic positive temperature coefficient of resistance consisting of conductive fine powder and crystalline polymer is generally characterized by having a positive temperature coefficient of resistance continuously from the low temperature range to the melting point of the crystalline polymer. Target. For this reason, the lower the temperature, the lower the resistance, and a large current flows when a heating device left at a low temperature starts to energize, which may interfere with the control devices such as power supply, switches, relays, and wiring. Causing abnormal overheating, smoking,
There is a risk of fire. However, if a positive / negative characteristic resistor having a negative resistance temperature characteristic in a low temperature region is electrically connected in series to this resistor and the both are thermally coupled, the start of energization may be at a low temperature. Since the positive and negative characteristic resistors have higher resistance, the applied voltage distributed to the positive and negative characteristic resistors becomes higher, and the applied voltage distributed to the organic positive resistance temperature coefficient resistor becomes smaller. The value can be kept small. That is, the rush current of the heating device can be controlled by appropriately setting the resistance temperature characteristics of the positive and negative characteristic resistors. In addition, the organic positive resistance temperature coefficient resistor is heated with heat generation and the temperature rises,
Since the positive and negative characteristic resistors thermally coupled to this also rise in temperature, the applied voltage distributed to the positive and negative characteristic resistors becomes small, and the heat generation characteristic of the organic positive resistance temperature coefficient resistor becomes the main factor. As a result, self temperature control is started. In this way, the inrush current is properly limited at the low temperature at the start of energization,
It is possible to realize a heating device which has almost the characteristics of a positive resistance temperature coefficient heating element when the energization is stable and has a sufficient output. Na
When the current is stable, the temperature coefficient of the organic positive resistance temperature coefficient is short-circuited.
Abnormal heat generation or abnormal current flow due to some abnormality such as
Temperature rises, the resistance of both the positive and negative characteristics rises to the negative resistance temperature.
The characteristic changes to a positive resistance-temperature characteristic and the resistance increases. That
The applied voltage distributed to the positive and negative characteristic
Applied to the organic positive temperature coefficient resistor.
The pressure becomes smaller. As a result, the temperature coefficient of the positive resistance temperature coefficient of the organic system is
The fever of the antibody is suppressed and the positive and negative characteristic resistors are applied with a large amount.
It generates heat under voltage, but due to the temperature coefficient of positive resistance at high temperature,
The resistance value suddenly rises, and the temperature gets tired without runaway.
Harmonize In this way, both positive and negative characteristic resistors are
Limit current and allow sufficient output when stable
It Also, it realizes safety in the event of an abnormality.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The heating device of the present embodiment has, for example, a circuit configuration shown in the circuit diagram of FIG. 1 and a configuration shown in the sectional view of FIG. In FIGS. 1 and 2, reference numeral 6 denotes an organic positive resistance temperature coefficient resistor made of carbon black and modified polyethylene, which has five resistor elements electrically connected in parallel. As shown, it has a large positive resistance temperature characteristic near the melting point of the modified polyethylene.
This positive resistance temperature coefficient resistor 6 has a heat generation temperature range of denatured polyester.
Although it is a relatively low temperature range below the melting point of ethylene, it has a large formation area.
The necessary heat source is formed by the operation. A resistor 7 having a negative resistance temperature characteristic in a low temperature range as shown in FIG. 4 is electrically connected in series to the positive resistance temperature coefficient resistor 6 and a voltage is applied by a power source 8 of a DC24V battery. There is. This resistor 7 has a negative resistance temperature in the low temperature range.
Temperature coefficient, but has a positive temperature coefficient of resistance in the high temperature range.
It has both positive and negative temperature coefficients of resistance. The positive resistance temperature coefficient resistor 6 and the positive / negative characteristic resistor 7 are fixed to the heating element support 9 and are blown by the blower 11 via the duct 10, and the resistors 6 and 7 are thermally blown. Is bound to. If both the positive and negative characteristic resistors 7 are not formed, the rush current is large and there is a problem in the battery balance, etc. However, by configuring as in this embodiment, the overall resistance is a combination of the resistors 6 and 7. becomes resistive, the inrush current can be suppressed to less than half, also energized stable when current is not affected so much on whether the positive and negative characteristic resistance element 7, the positive
The temperature coefficient of resistance of the resistor 6 mainly generated heat, and exhibited extremely good heat generation characteristics. Also, when energization is stable
Positive temperature coefficient resistor 6 is positive due to some abnormality such as short circuit
Even if a large voltage is applied to the negative characteristic resistor 7,
Body resistance temperature coefficient is also a heating element, use of this heating device
Since it withstands voltage, safety can be maintained. Further, by providing the positive and negative characteristic resistors 7 with an overheat preventing function body such as a temperature fuse, even if an abnormality such as a short circuit occurs in the organic type resistor 6, the heating device can be safely energized. Can be made.

Next, FIG. 5 is a perspective view showing the structure of a heating element of a heating device according to a second embodiment of the present invention. A pair of electrodes 14 and 15 are arranged on a metal substrate 12 having excellent thermal conductivity via an electric insulating layer 13, and a positive resistance temperature coefficient resistor 16 is formed between the electrodes 14 and 15, and further on the substrate 12. A positive and negative characteristic resistor 17 is formed on the
The resistor 16 and the resistor 17 are electrically connected in series. In the case of this embodiment as well, similar to the above-mentioned embodiments, the inrush current can be limited, the safety can be improved, and the electric power at the time of stable energization is hardly affected, and an appropriate output can be obtained. It was

Next, FIG. 6 is a perspective view showing the structure of a heating element of a heating device according to a third embodiment of the present invention. Organic positive resistance temperature coefficient resistors 19 and 20 as shown in FIG. 13 are attached to a heat sink 18 made of an aluminum plate, and air is blown in the direction A shown in FIG. Note that, in FIG. 6, ducts, blowers, etc. are omitted. These resistors 19, 2
A barium titanate-based resistor 22 is arranged on the heat dissipation plate 21 in the downstream direction of 0. The resistors 19 and 20 are electrically connected in parallel, and the resistors 19 and 20 and the resistor 2 are electrically connected in parallel.
2 are electrically connected in series. FIG. 7 shows the resistance-temperature characteristics of the organic resistors 19 and 20, and FIG. 8 shows the resistance-temperature characteristics of the barium titanate-based resistor 22. The barium titanate-based resistor 22 is basically a positive resistance temperature coefficient resistor, but in the low temperature range, specifically, in FIG. 8 of this embodiment, it is negative until near the Curie temperature of about 220 ° C. It has a resistance temperature characteristic, and since it has a series resistance of this characteristic and the resistance temperature characteristic of the organic resistors 19 and 20 of FIG. 7, the inrush current is limited as in the above-mentioned embodiment,
When the energization is stable, a sufficient output is realized.

Here, the crystalline polymer of the organic resistors 19 and 20 is a modified high-density polyethylene and has a melting point of 13
The temperature is 0 ° C., which is lower than about 220 ° C. which is the Curie temperature of the barium titanate-based resistor 22. The resistors 19 and 20 and the resistor 22 are thermally coupled via air blowing, and the organic resistors 19 and 20 have a large positive resistance temperature characteristic in the vicinity of this melting point. Since the system resistor 22 does not rise to a temperature higher than the melting point of the organic resistor and can be suppressed at a temperature below the Curie temperature, the current at the time of stable energization is reduced or unstable. It never becomes. Further, even when a large voltage is applied to the barium titanate-based resistor due to some abnormality such as a short circuit of the organic-based resistors 19 and 20 at the time of stable energization, the positive resistance temperature coefficient heating element itself causes the heating device to Since it withstands the working voltage, it has no safety problem and has an extremely effective effect. Further, by providing the barium titanate-based resistor 22 with an overheat-preventing function body such as a temperature fuse, it is possible to safely stop the energization of the heating device and further enhance the safety.

Next, FIG. 9 is a perspective view showing the structure of a heating element of a heating device according to a fourth embodiment of the present invention. Reference numeral 23 denotes a positive resistance temperature coefficient resistor composed of twelve barium titanate-based positive resistance temperature coefficient resistor elements. By diffusing this heat with aluminum corrugated fins 24 and blowing it in the B direction, The heat of the fins 24 is transferred to the air to obtain hot air. In addition, 25 is a terminal for electric power feeding.
Due to this positive resistance temperature characteristic, the heating element with such a structure does not glow red like a nichrome heater, has high safety, and has the excellent features that it is possible to control heat generation according to the air volume or speed distribution. It has been put to practical use. The barium titanate-based positive temperature coefficient resistor 23 has a characteristic as shown in FIG. 10, and the Curie temperature is about 150 ° C., but the resistance decreases from a temperature exceeding about 250 ° C. . In FIG. 9, an organic positive resistance temperature coefficient resistor 26 is arranged in the air-blowing region in the B direction, and the melting point temperature of this resistor material is 130 ° C., and as shown in FIG. It has a large positive resistance temperature characteristic in the vicinity of ° C and has a characteristic that the resistance hardly decreases even at a temperature exceeding 130 ° C. In addition, in FIG. 9, the duct, the blower, and the like are omitted. The barium titanate-based positive resistance temperature coefficient resistor 23 and the organic-based positive resistance temperature coefficient resistor 26 are electrically connected in series, and the normal energization characteristics are almost unchanged. When the temperature of the resistor 23 becomes higher than 250 ° C. or the resistance thereof is lowered due to some abnormality, the positive resistance temperature characteristic of the organic resistor 26, and even at the temperature of more than 130 ° C. of the melting point. Due to the characteristic that the resistance is hardly reduced, it also has an effect of suppressing abnormalities such as abnormal heat generation, smoke generation, and ignition. In the case of only barium titanate-based resistors, the maximum current at the start of energization is when the temperature of the heating element is at 100 ° C. level, which varies depending on the heat radiation state and reaches the maximum current after a certain period of time. However, it is also possible to suppress this maximum current by introducing an organic positive resistance temperature coefficient resistor having an appropriately set positive resistance temperature characteristic.

The heating device of the above-described embodiment limits the inrush current at the start of energization and realizes a sufficient output when the energization is stable. When the temperature is higher than the temperature of the resistor and lower than the melting point of the organic resistor material, that is, higher than the normal operating temperature range, the organic resistor and the positive / negative characteristic resistor or titanium Since the combined resistance with the barium oxide-based resistor has a positive temperature coefficient of resistance, if only the thermal coupling degree of these two resistors is adjusted, the positive resistance temperature characteristic provides higher safety. It will be realized. Further, the applied voltage distributed between the positive and negative characteristic resistors or the barium titanate-based resistor and the organic positive temperature coefficient resistor is unstable when the thermal coupling state is lowered for some reason. However, if one of the voltages is at least twice the voltage of the other when the heating device is stable, the stability is extremely high and there is no such problem. Is preferably made of a material that can withstand the operating voltage of this heating device.

In the present embodiment, an example in which two resistors are connected in series is shown, but any circuit configuration may be used as long as it has such a connecting portion, for example, FIG. The circuit configuration may be as shown. In the case of this circuit, the operating voltage is applied to the organic positive resistance temperature coefficient resistor 27 immediately after the start of energization, but the applied voltage distributed to the organic positive resistance temperature coefficient resistor 28 is positive or negative. Since the characteristic resistor 29 has a high resistance, the voltage is relatively low, and the overall inrush current is suppressed, but as the temperature rises, both the positive and negative characteristic resistors 29 become lower in resistance. The applied voltage distributed to the resistor 28 also increases and sufficient heat generation is obtained. In addition, 30 is an AC power supply.

If the organic resistor is made thin and a pair of electrodes are formed on both sides of this resistor, high output can be achieved as described above, but this resistor is combined with a heat radiator to conduct electricity. And, in the relationship between the heat capacity and the thermal conductivity of this heat radiator or the like, the thermal coupling state between the organic resistor and the positive / negative characteristic resistor or the barium titanate resistor varies,
It is also possible that the behavior of the normal applied voltage distributed to both is changed. However, a heat radiator is formed on at least one of the pair of electrodes arranged on both sides of this resistor, and the other is formed on the other side.
By configuring a positive / negative characteristic resistor or a barium titanate-based resistor, it is possible to realize inrush current limitation at the start of energization with high sensitivity, and this heating device becomes safer and more reliable.

By the way, as materials for the organic positive temperature coefficient of resistance coefficient, low density polyethylene, medium density polyethylene, high density polyethylene, linear polyethylene, ethylene vinyl acetate copolymer, ethylene acrylic acid copolymer, Among ionomers, polypropylene, polyamide, polyvinylidene fluoride, polyester, crystalline polymers such as organic acid-modified polyethylene such as acrylic acid and maleic acid, and carbon black such as thermal black, furnace black, channel black and acetylene black. It may be an appropriate combination with a conductive material exhibiting a remarkable positive resistance temperature characteristic, or may be one to which another material is added.

With such materials / structures, an organic positive temperature coefficient of resistance coefficient having high output and high stability can be formed. Further, conductive fine powder is mixed and dispersed in a crystalline polymer, and then crosslinked to form fine particles. By mixing and dispersing the converted conductive fine particles in other resin materials, it is possible to make the conductive fine powder difficult to move and to realize extremely high resistance stability against rapid heat load fluctuations such as air blowing. , As shown in FIG.
A material having a property that resistance is hardly reduced even in a temperature range higher than the melting point has been found.

Further, the barium titanate-based positive temperature coefficient resistor has a barium titanate-based main component and a semiconductor such as a rare earth element such as Y, La or Ce, or a transition element such as Nb or Ta. It is known that elements are added and mixed and heated and sintered at a high temperature. This barium titanate-based positive resistance temperature coefficient resistor has a positive resistance temperature characteristic in which the resistance value changes rapidly at the Curie point. Although this resistance characteristic can be expressed by the sum of bulk and grain boundaries, it is generally below the Curie temperature. It is known that the bulk resistance is dominant at the temperature of 1, and the grain boundary resistance is dominant at the Curie temperature or higher. By setting the heat sintering condition, the positive resistance-temperature characteristics can be adjusted, in particular Ru negative can der varying the resistance temperature coefficient at a low temperature range by the adjustment in the bulk. It should be noted that the positive of the present invention
The negative characteristic resistor is not limited to such a ceramic type resistor, and as long as it has a negative resistance temperature characteristic in a low temperature range and has a structure capable of withstanding a large current of such a heating device, it is an inorganic substance. The resistor is not limited to the system material, and may be a resistor made of an organic polymer material or the like .

[0021]

As described above, according to the heating device of the present invention, the organic positive resistance temperature coefficient resistor exhibits negative resistance temperature characteristics in the low temperature range and positive resistance temperature characteristics in the high temperature range.
Since both the positive and negative characteristic resistors showing are electrically connected in series, and both are thermally coupled, the following effects are obtained,
It is extremely useful in practice.

(1) By setting the resistance-temperature characteristics of both the positive and negative characteristic resistors, the inrush current at the start of energization can be controlled to an appropriate current value or less, safety can be improved, and the positive resistance temperature coefficient heat generation can be achieved. It is possible to realize a heating device in which a sufficient output is obtained by the body's independent heat generation .

(2) By adjusting the combined resistance of the positive / negative characteristic resistor or the barium titanate-based resistor and the organic positive resistance temperature coefficient resistor in an appropriate thermal coupling state, heat generation is efficient and safe. An ideal heating device with high properties can be obtained.

(3) Since both the positive and negative characteristic resistors or the barium titanate type resistor and the organic positive temperature coefficient resistor are electrically connected in series, by any chance one of the resistors is Even if the resistance is abnormally lowered or short-circuited, the positive resistance temperature characteristic of the other resistor or the overheat prevention function that is thermally coupled to this resistor can safely operate the heating device. You can

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a heating element of a heating device according to an embodiment of the present invention.

FIG. 2 is a sectional view of the heating device.

FIG. 3 is a resistance-temperature characteristic diagram of the heating element.

FIG. 4 is a resistance temperature characteristic diagram of the heating element.

FIG. 5 is a perspective view of a heating device according to a second embodiment of the present invention.

FIG. 6 is a perspective view of a heating device according to a third embodiment of the present invention.

FIG. 7 is a resistance temperature characteristic diagram of the heating element.

FIG. 8 is a resistance temperature characteristic diagram of the heating element.

FIG. 9 is a perspective view of a heating device according to a fourth embodiment of the present invention.

FIG. 10 is a resistance temperature characteristic diagram of the heating element.

FIG. 11 is a resistance-temperature characteristic diagram of a heating element of a heating device according to a fifth embodiment of the present invention.

FIG. 12 is a circuit diagram showing the configuration of a heating element of a heating device according to a sixth embodiment of the present invention.

FIG. 13 is a perspective view of a heating element used in a conventional heating device.

[Explanation of symbols]

6, 16, 19, 20, 20, 26, 27, 28 Positive temperature coefficient of resistance of organic resistors 7, 17, 29 Positive and negative characteristic resistors 14, 15 Electrodes 18, 21 Heat sink 22, 23 Barium titanate positive Temperature coefficient of resistance

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-1-204383 (JP, A) JP-A-5-94863 (JP, A) JP-A-5-47457 (JP, A) JP-A-4- 292888 (JP, A) JP-A-53-7853 (JP, A) Actually developed 3-127797 (JP, U) Actually developed 55-44534 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H05B 3/10 F24H 3/04 303 H05B 3/00 365 H05B 3/14 F24C 7/04-7/06

Claims (4)

(57) [Claims] 1. An organic positive temperature coefficient of resistance comprising a conductive fine powder and a crystalline polymer, and a negative resistance temperature characteristic in a low temperature region electrically connected in series to the resistor.
Shows and changes to positive resistance-temperature characteristics in high temperature range
A positive and negative characteristic resistor , the organic resistor and the positive and negative characteristic resistor are thermally coupled by a heat conductor or air flow, and the organic resistor and the positive and negative characteristic
The formation ratio with the resistor is mainly the organic resistor.
Both positive and negative characteristics are
The resistor remains in a low temperature range where it exhibits negative characteristics, and the organic substance is in a temperature range higher than the temperature of the organic resistor when the heating device is energized and lower than the melting point of the organic resistor material. A heating device configured such that a combined resistance of a system resistor and the negative characteristic resistor has a positive resistance temperature coefficient. 2. An organic material comprising electrically conductive fine powder and a crystalline polymer.
System positive resistance temperature coefficient resistor and this resistor electrically in series
Negative resistance temperature characteristics in the low temperature range
Shows and changes to positive resistance-temperature characteristics in high temperature range
Positive resistance temperature coefficient of barium titanate system having both positive and negative characteristics
Several resistors, the organic resistor and the titanium
The formation ratio with the barium acid-based resistor is the above-mentioned organic resistance.
The body is the main body, and the barium titanate-based resistor is
A temperature higher than the melting point of the crystalline polymer of the organic resistor.
Having a Curie temperature, the organic resistor and the titanium
A barium oxide-based resistor is a heat conductor or a blower.
When the heating device is energized and stable,
The barium titanate-based resistor exhibits negative characteristics at low temperatures.
Stay in the area, the resistance of the organic system at the time of stable energization of this heating device
Higher than the body temperature, higher than the melting point of this organic resistor material
And the negative characteristic in the low temperature range
So that the combined resistance with the resistor has a positive temperature coefficient of resistance
A heating device configured. 3. A positive / negative characteristic resistor or barium titanate.
Overheat prevention function is thermally connected to the resistor
The heating device according to claim 1. 4. The organic resistor is thin-walled, and
Of which is constituted a pair of electrodes on both sides, the pair of electrodes
A heat radiator is configured on at least one of the
By constructing a resistor or a barium titanate resistor
The heating device according to claim 1 or 3.