JPH08189639A - Heating body structure - Google Patents

Abstract

PURPOSE: To provide a highly durable heating body structure which carry out heating of a heat generating part evenly with the energization of a heating body element. CONSTITUTION: In a heating body structure 10, a heating pipe 3 made of a heat resistant and anticorrosive material forming a heating part is mounted sticking out on a hollow body 1 where a connector 2 is arranged through an insulation member 4 and a heating body element 5 connected to the connector 2 is arranged in the heating pipe 3. The heating pipe 3 having the heating body element 5 positioned thereon is filled with an electrically insulating material 6 while a heat pipe 7 is buried therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating element structure such as a glow plug used in a diesel engine.

[0002]

2. Description of the Related Art Conventionally, a diesel engine has used a heating element structure which constitutes a glow plug of a starting assist device, as disclosed in, for example, Japanese Patent Application Laid-Open No. 1-157084.

Further, referring to FIG. 2 of a conventional heating element structure, the heating element structure 20 has a heating portion, and the heating portion is arranged in a combustion chamber formed in a cylinder head of a diesel engine. . Such a heating element structure 20
Is a heat generating pipe 2 made of a heat-resistant food material which constitutes a hollow main body 21 in which a connector 22 is arranged via an insulating member 24 and a heat generating portion protruding from the hollow main body 21 and attached.
3. The heating element 23 is arranged in the heating pipe 23 and connected to the connector 22, and the electrical insulating material 26 filled in the heating pipe 23 in which the heating element 25 is located. In the heating element structure 20, a large current from the battery is applied to the heating element 25, the heating element constituted by the heating pipe 23 is heated in a short time by the heating element 25, and the fuel contacts the heating element. The fuel is ignited and burned.

[0004]

However, the conventional glow plug as described above has a heat resistance and a strength against a heat shock when used in a high temperature combustion chamber such as a heat shield engine.
It could not be said that the high temperature strength was sufficient. Further, in a conventional glow plug, a heating wire coil made of a tungsten carbide wire and a resistor coil made of a Ni wire coil are connected to each other, and both are made of materials having different resistance temperature coefficients, or Since the heating element and the resistance element of the winding are manufactured in different shapes, there is a problem that the Ni wire is disconnected due to overheating during use or deteriorates due to aging, and the structure becomes complicated,
The cost and strength were not satisfactory.

Further, in the conventional heating element structure 20 as shown in FIG. 2, when a constant voltage is applied to the heating element 25,
In the early stage when the temperature of the heat generating pipe 23 forming the heat generating portion is low, a large amount of current flows through the heat generating element 25 and the temperature rises sharply. When the temperature of the heat generating pipe 23 increases, the heat generating element 2
The current flowing through No. 5 is reduced, and it stabilizes at a lower temperature than the initial temperature. However, when a current is applied to the heating element 25,
As shown in the graph of FIG. 3, an extremely high temperature region C and an extremely low temperature region D that are not so high are formed in the heat generating pipe 23, so that the heat generating pipe 23 itself is not uniformly heated. In the conventional heating element structure 20, since the above-described phenomenon of the high temperature region C and the low temperature region D occurs,
In the initial stage of the voltage load, an overcurrent flows through the heating element 25, causing melting and damage of the heating element 25 and the like.

An object of the present invention is to solve the above problems. A heat pipe is arranged in the vicinity of a heat generating portion, and excess heat generation amount in a high temperature region of a heating element in the initial stage of voltage load is transferred to a low temperature region by the heat pipe. Accordingly, it is an object of the present invention to provide a heating element structure capable of preventing the temperature of the heating element from excessively rising, preventing melting and destruction of the heating element, and enabling uniform heating of the heating element.

[0007]

The present invention is configured as follows to achieve the above object. That is, the present invention is a body in which a connector is arranged via an insulating member,
A heat-generating pipe made of a heat-resistant material that constitutes a heat-generating portion protruding from the main body, a heat-generating element arranged in the heat-generating pipe and connected to the connector, and the heat-generating pipe in which the heat-generating element is located. And a heat pipe made of a heat-resistant alloy embedded in the heat-generating pipe in which the heat-generating element is located, and a heat-generating body structure.

In this heating element structure, the heating element is made of a Ni-based alloy such as a nichrome alloy. The heat medium sealed in the heat pipe is one or more selected from metal elements of sodium, mercury, potassium, lithium, silver and cesium, or one or more selected from ammonium salt and water, or ammonia. ,
Freon, pentane, acetone, methane, methanol,
It is one or more selected from ethanol. Further, the electrical insulation material is magnesium oxide powder.

[0009]

The heating element structure according to the present invention is constructed as described above and operates as follows. That is, in this heating element structure, a heating pipe made of a heat-resistant and food-resistant material that protrudes from a main body in which a connector is arranged and constitutes a heating portion is attached, and a heating element connected to the connector is arranged in the heating pipe. The heat generating pipe in which the heat generating element is located is filled with an electric insulating material, and the heat pipe made of heat-resistant metal is embedded in the heat generating pipe in which the heat generating element is located. When the low temperature region and the low temperature region are generated, the excessive heat generation amount in the high temperature region of the heat generating portion is transferred to the low temperature region by the heat pipe, and the entire heat generating portion is adjusted to a uniform temperature in the early stage of the voltage load. Can be prevented from melting and damage.

In this heating element structure, as shown in FIG. 3, when a high temperature region A and a low temperature region B are generated in the heat generating portion, excessive heat generation amount in the high temperature region A is transferred to the low temperature region B by the heat pipe. It can be seen that the temperature difference between the high temperature region A and the low temperature region B is smaller than that of the conventional one, and is stable over time.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a heating element structure according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a heating element structure according to the present invention.

This heating element structure 10 has a hollow main body 1 in which a connector 2 is arranged via an insulating member 4, and is made of a material having excellent heat resistance and corrosion resistance which is attached so as to project from the hollow main body 1. The heat generating pipe 11 constitutes the heat generating portion 11. Inside the heating pipe 3, a heating element 5 such as a heater coil connected to the connector 2 is arranged. An electric insulating material 6 is filled in the heating pipe 3 in which the heating element 5 is located. This heating element structure 10 is particularly characterized in that the heat pipe 7 is embedded in the heating pipe 3 in which the heating element 5 is located. Heat pipe 7
Is a glass fiber inside the heat-resistant metal pipe 8 made of a material such as aluminum alloy, stainless steel, or copper.
A wick material (not shown) made of ceramics fibers and reticulated copper wire is arranged, the inside of the pipe 8 is decompressed, and the heat medium 9 such as sodium, freon, ammonia, or water enclosed in the pipe is enclosed. The heat transfer is performed by the movement of the vapor of the heat medium 9 in the pipe 8 and the transfer of the latent heat of vaporization of the heat medium 9 in the pipe 8.

The heating element 5 is made of a Ni-based wire, a Ni-based alloy such as a nichrome alloy, or a tungsten wire, and is made of a material having a positive temperature coefficient of resistance to form a self-current control type glow plug. Can be configured.
The heat pipe 7 is composed of a pipe 8 made of a heat-resistant metal and a heat medium 9 enclosed in the pipe 8. The inner surface of the pipe 8 is made of glass fiber, ceramic fiber, wick material such as reticulated copper wire. Are arranged. As the heat medium 9 used, one or more metal elements selected from sodium, mercury, potassium, lithium, silver and cesium can be used. Alternatively, as the heat medium 9, one or more selected from ammonium salts and water can be used. Further, as the heat medium 9, one or more selected from ammonia, freon, pentane, acetone, methane, methanol and ethanol can be used.

Further, the electric insulating material 6 is made of magnesium oxide powder, ceramic fibers such as SiC, TiO ₂ , TiN.
_The heat generating pipe 3 is filled with an electrically insulating material such as Si ₃ N ₄ non-shrinkable ceramics containing ₂ . The heat generating pipe 3 can be made of Incoloy 903, a Ni—Cr-based material having excellent heat resistance and corrosion resistance, but can also be made of heat resistant and high strength ceramics such as Si ₃ N ₄ .

The heating element structure 10 is constructed as described above and has the following functions. It has been found that the heating element structure 10 is different from the conventional heating element structure 20 having no heat pipe in that the heat pipe 7 is provided as follows. A voltage of 15 V is applied to each of the heating element structure 10 of the present invention and the heating element structure 20 of the conventional product to generate the heating element structure 10 and the heating element structure 2.
The temperature change with time of 0 was measured by a radiation thermometer. Heater structure 1 in initial VS of voltage load
The temperature changes of the high temperature region A point and the low temperature region B point of 0, and the high temperature region C point and the low temperature region D point of the heating element structure 20 resulted as shown in FIG. This heating element structure 10
Since the heat pipe 7 is embedded in the heat generating pipe 3,
It can be seen that the excessive temperature rise in the high temperature region A in the initial voltage load VS becomes low and the temperature in the low temperature region B rises by that amount, and the temperature is uniformly heated as a whole and there is no temperature difference. .

Here, the heating element structure 10 and the heating element structure 20.
When the voltage to the heating element structure 10 is increased to 32V
Up to this point, the Niurom wire of the heating element 5 did not break, but in the heating element structure 20, the Niurom wire of the heating element 25 was broken at 24V. In other words, it can be inferred that the heat generating structure 10 has the temperature of the heat generating portion made uniform by the heat pipe 7 so that the heat generating element 5 is not locally overheated and the durability is improved. On the other hand, in the heating element structure 20, it is presumed that the heating element 25 has a local overheat state in a high temperature region and the heating element 25 is disconnected.

[0017]

The heating element structure according to the present invention is constructed as described above and has the following effects. That is,
In this heating element structure, a heating element connected to a connector is arranged in a heating pipe made of a heat-resistant material, and the heating pipe in which the heating element is located is filled with an electric insulating material and the heat pipe is Since it is embedded, the heating part can be heated to a uniform temperature distribution with a simple structure, no local overheating occurs, the heating part can be stabilized at the optimum temperature, and it is durable. It is rich in This heating element structure can be used as a heating element that generates heat by energization, and by selecting the material of the heating element, a heating element having a self-current control type function can be configured. It can be used as a glow plug.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a heating element structure according to the present invention.

FIG. 2 is a sectional view showing an example of a conventional heating element structure.

FIG. 3 is a graph showing a temperature rising state of a heat generating portion between the heat generating structure according to the present invention and the conventional heat generating structure.

[Explanation of symbols]

 1 Hollow Body 2 Connector 3 Heating Pipe 4 Insulating Member 5 Heating Element 6 Electrical Insulation Material 7 Heat Pipe 8 Heat-Resistant Metal Pipe 9 Heating Medium 10 Heating Element Structure

Claims (4)

[Claims] 1. A main body in which a connector is arranged via an insulating member, a heat-generating pipe made of heat-resistant food material constituting a heat-generating portion protruding from the main body, and arranged in the heat-generating pipe and in the connector. A heating element connected to the heating element, an electrical insulating material filled in the heating pipe in which the heating element is located, and a heat pipe embedded in the heating pipe in which the heating element is located. Characteristic heating element structure. 2. The heating element is Ni such as a nichrome alloy.
The heating element structure according to claim 1, wherein the heating element structure is a base alloy. 3. The heat medium sealed in the heat pipe is one or more selected from metal elements of sodium, mercury, potassium, lithium, silver and cesium, or one or more selected from ammonium salt and water. Or one or more selected from ammonia, freon, pentane, acetone, methane, methanol, ethanol, and the heating element structure according to claim 1. 4. The heating element structure according to claim 1, wherein the electrical insulating material is magnesium oxide powder.