JP3889198B2 - Electric heater structure and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric heater structure suitable for use in, for example, a firing furnace for electronic parts, and an improvement in the manufacturing method thereof.
[0002]
[Prior art]
Conventionally, a kneading obtained by adding an inorganic binder to ceramic fibers or the like as an electric heater structure in which a coiled heating wire (hereinafter referred to as an electric heating coil) wound in a spiral shape is supported by a heat insulating material. An object is formed in a plate shape to form a seat, and the bottom of the electric heating coil is press-fitted into the seat, and the electric heating coil is seated by the shrinkage force and the binding force when the seat made of the kneaded material is dried and solidified. An electric heater structure (see Japanese Patent No. 2903131) is known which is held firmly.
[0003]
In addition, a kneaded material prepared by adding an inorganic binder to ceramic fibers is poured in a wet state into a mold in which an electric heating coil having a predetermined shape is set, and most of the electric heating coil is exposed from the kneaded material. There is known an electric heater structure (see Japanese Patent No. 26522266) which is constituted by demolding and drying after being fixed in the state of being made.
[0004]
[Problems to be solved by the invention]
Like the conventional electric heater structure mentioned above, in the structure where the electric heating coil is embedded at the same time when molding the heat insulating material put in the mold, the electric heating coil is closely fixed to the heat insulating material in a wide area and fixed integrally. Therefore, when the electric heating coil expands and contracts due to energization / non-energization of the electric heating coil, a phenomenon occurs in which the heat insulating material in contact with the electric heating coil is cracked or chipped. Causes the occurrence. As it progresses further, the heat insulation material collapses and generates dust.
For this reason, the electric heater having the above structure cannot be used in a place where cleanliness is required during firing, such as a firing furnace for electronic components.
[0005]
In addition, in the structure in which the electric heating coil is embedded at the same time as the molding of the heat insulating material as described above, since the electric heating coil adheres to the heat insulating material in a wide area, a large proportion of the heat generated by the electric heating coil escapes directly to the heat insulating material, The heater heat radiation efficiency is poor.
[0006]
Furthermore, in the structure in which the support seat body of the electric heating coil is molded using the molding die as described above, the size of the electric heater is determined by the molding die, so there is a problem that the size design cannot be freely changed.
[0007]
The present invention has been made to solve the above-described problems of the conventional products, and in particular, an electric heater structure that can improve the cleanliness, improve the heat radiation efficiency of the heater, and free the design of the heater size. And its manufacturing method.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the electric heater structure according to the present invention includes an electric heating coil fitted into one of the plate-like heat insulators from among the plate-like heat insulators to be assembled. a groove, said formed in communication with the fitting groove of the heating coil, provided with a plurality through-slots made in the heat radiating groove portion to release to the outside of the heating coil heat from the other plate surface in the through slot The groove width of the heat radiating groove is narrower than the groove width of the fitting groove of the electric heating coil, and the communication part of the fitting groove of the electric heating coil with the heat radiating groove is formed in a curved shape according to the shape of the electric heating coil. the electric heating coil is disposed in contact with said communicating portion, and summarized in that the other plate-shaped heat insulators are superimposed as a lid to the heating coil fitting side of the plate-like heat insulating member By that.
[0009]
In addition, the manufacturing method of the electric heater structure according to the present invention includes an electric heating coil in which an electric heating coil is fitted from one plate surface to a plate-like heat insulator formed into a plate shape from a slurry raw material prepared by adding an inorganic binder to inorganic fibers . and fitting groove, when the formed in communication with the fitting groove of the heating coil is formed by cutting a plurality of through-slots made in the heat radiating groove portion to release to the outside of the heating coil heat from the other plate face, said The groove width of the heat radiating groove portion is formed narrower than the groove width of the fitting groove portion of the electric heating coil, and the communication portion of the fitting groove portion of the electric heating coil with the heat radiating groove portion is formed in a curved shape according to the shape of the electric heating coil, fitted an electric heating coil fitting groove of the heating coil so as to make contact with the communicating portion, the lead end of the heating coil is fitted in each through-slot Connect, and summarized in that to fix superposed as lid another plate heat insulator to the heating coil fitting side of the plate-like heat insulator.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In a preferred embodiment of the present invention, as shown in FIGS. 1 to 3, of the overlapping plate-shaped heat insulator A ₁ to be assembled, A _2, in one thermal insulation body A _1, cross-sectional shape of one A groove portion 1a into which the electrothermal coil B is fitted from the plate surface, a heat radiating groove portion 1b that communicates with the groove portion 1a and regulates the coil fitting depth and discharges the heat of the electric heating coil from the other plate surface to the outside, and the groove portion In order to guide and connect the lead terminals of the electric heating coils fitted in the respective through-groove holes, provided in parallel with a plurality of through-groove holes 1 formed by coil portion receiving recesses 1c formed on the inner surface of 1a. the contact recess 1d formed in the heat insulator a _1, constituting superimposed to the heating coil fitting side of the thermal insulator a ₁ a thermal insulator a ₂ as the lid.
[0011]
【Example】
1 to 3 show an embodiment of the present invention.
1 to 3, A ₁ and A ₂ are two plate-like heat insulators that constitute the main part of the electric heater structure, and both plate-like heat insulators can be assembled in a stacked manner.
As the plate-like heat insulators A ₁ and A ₂ , a plate-like body is used which is formed into a plate shape by a suction dehydration molding method from a slurry raw material prepared by adding an inorganic binder to the inorganic fiber as a main material.
[0012]
The preferable example of manufacture of the plate-shaped heat insulating body which consists of an inorganic fiber below is shown.
(Composition raw material)
(I) Silica alumina fiber 90 parts by weight (silica component 50% by weight, alumina component 50% by weight, average fiber length of about 200 μm
(Average fiber diameter 3μm)
(B) Colloidal silica having an average particle diameter of 20 nm 10 parts by weight (c) Flocculant 1 part by weight (d) Water 4000 parts by weight From a slurry raw material obtained by mixing the above raw materials, a plate-like molded product is obtained by a suction dehydration molding method. And the molded product is dried at 105 ° C. for 24 hours to obtain a plate-like inorganic fiber heat insulator. The inorganic fiber insulation thus obtained has a density of approximately 0.2 g / cm ³ and is porous, has excellent heat insulation properties, and is lightweight and can be easily subjected to mechanical processing such as cutting and cutting. Has physical properties.
[0013]
Of the plate-like heat insulators A ₁ and A ₂ manufactured by the above method, the heat insulator A ₁ has a plurality of straight through-slot holes ₁ into which the electric heating coil B is fitted at a predetermined interval. Are provided in parallel.
[0014]
Each through-groove 1 has a groove 1a into which the electric heating coil B can be inserted from one plate surface of a heat insulating body having a plate-like cross-sectional shape, and the insertion depth of the electric heating coil due to a narrower groove width than the coil fitting groove 1a. And a heat radiating groove 1b that can discharge the heat of the electric heating coil from the opposite plate surface to the outside. In the illustrated example, a recess 1c for receiving the coil portion of the electric heating coil B and maintaining the coil pitch is formed on the inner surface of the electric heating coil fitting groove 1a.
[0015]
The plate-like heat insulator A ₁ is formed with a connecting recess 1 d for guiding and connecting the lead terminals of the electric heating coils fitted in the adjacent through-slot holes 1. In the drawing, reference numeral 2 denotes a coil lead terminal connecting sleeve.
The plate-like heat insulator A ₂ is overlapped on the side of the plate-like heat insulator A _{1 where} the electric heating coil is fitted, and is integrated with a fastener such as a bolt or a nut. 3 is a bolt insertion hole.
[0016]
The electric heater structure configured as described above has the following characteristics.
1) In the conventional structure in which the electrothermal coil is embedded in the inorganic fiber insulation body, as described above, the phenomenon that the seat body is cracked or chipped due to the expansion and contraction of the electrothermal coil occurs, generating dust. However, in the present invention, the electric heating coil is merely fitted in the groove, and is not tightly integrated with the plate-like heat insulator. There is almost no problem. Therefore, the cleanliness of the electric heater structure can be improved.
2) In the structure in which the electric heating coil is fitted in the groove portion of the inorganic fiber heat insulating body, the contact area of the electric heating coil heat insulating body is limited, so that the rate of heat radiation increases and the radiation efficiency increases.
3) The inorganic fiber heat insulator that supports the electric heating coil is not made using a mold, and a separately manufactured plate-like heat insulator can be used as a material. is there.
Further, if the mold is not required, the standard size is not provided, and therefore the size of the electric heater can be freely designed.
4) As a heat insulator that supports the electric heating coil, when using a plate body formed by suction dehydration molding of a slurry raw material prepared by adding an inorganic binder to an inorganic fiber, a through-slot hole for fitting the electric heating coil In addition, it is possible to easily form a recess for connecting the electrothermal coil lead terminal by cutting.
5) Further, for example, when NC machining means is applied to the cutting, there is an advantage that high-precision and rapid cutting can be performed, and further, the NC program can cope with small-scale production.
6) Since the production days of the mold are zero, the product delivery time can be shortened in combination with NC processing.
[0017]
In the above embodiment, the recess 1c for receiving the coil portion of the electric heating coil is provided on the inner surface of the fitting groove portion 1b of the electric heating coil so as to maintain the coil pitch. However, the recess 1c is omitted, and the diameter of the electric heating coil is reduced. It is possible to apply a means for fitting the electric heating coil in a state where an adhesive material such as a refractory mortar is applied to the inner surface of the groove portion 1b formed to have a width suitable for the above, and holding it with the adhesive material. In that case, the adhesive may be applied entirely or partially.
[0018]
There is also a means for holding the electric heating coil with the elastic force of the electric heating coil and the elastic force of the heat insulating material, with the width in the groove being slightly narrower than the diameter of the electric heating coil.
Moreover, it is also possible to make the inner surface of the fitting groove of the electric heating coil into a corrugated shape or an uneven shape (for example, a sawtooth shape) and hold the coil there. In this case, if the holding power of the electric heating coil is obtained, a slight deviation in the coil pitch is allowed.
Moreover, you may combine suitably the electrothermal coil holding means quoted above.
[0019]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an electric heater structure and a manufacturing method thereof that can improve the degree of cleanliness, improve the heater heat radiation efficiency, and free the design of the heater size.
[Brief description of the drawings]
FIG. 1 is a perspective view of an electric heater structure showing an embodiment of the present invention.
FIG. 2 is a side view showing an assembly configuration of an electric heater structure.
FIG. 3 is a plan view showing a configuration in which an electric heating coil is fitted into a plate-like heat insulator.
[Explanation of symbols]
A ₁ , A ₂ plate-like heat insulator B Heating coil 1 Through groove hole 1a Heating coil fitting groove 1b Heat radiation groove 1c Recess 1d for receiving the coil part of the heating coil 1d Contacting recess 2 for connecting the lead terminal of the heating coil 2 of the heating coil Lead terminal connection sleeve 3 Bolt insertion hole

Claims (7)

Of the plate-like heat insulators assembled in layers, one plate-like heat insulator is formed in communication with the fitting groove portion of the electric heating coil into which the electric heating coil is fitted from one plate surface, and the fitting groove portion of the electric heating coil, There are provided a plurality of through-slot holes composed of heat radiating grooves that discharge heat from the other plate surface to the outside,
In the through-groove hole, the groove width of the heat radiating groove is narrower than the groove width of the fitting groove of the electric heating coil, and the communication portion of the fitting groove of the electric heating coil with the heat radiating groove is curved to match the shape of the electric heating coil. And the electric coil is arranged in contact with the communication part,
An electric heater structure in which the other plate-like heat insulator is overlapped as a lid on the electric heat coil fitting side of the plate-like heat insulator. The electric heater structure according to claim 1, wherein a recess for receiving a coil portion of the electric heating coil is formed on an inner surface of the electric heating coil fitting groove. The electric heater structure according to claim 1, wherein a plate body formed from a slurry raw material prepared by adding an inorganic binder to an inorganic fiber is used for the plate-like heat insulator. The electric heater structure according to claim 3, wherein the fitting groove is slightly narrower than the electric heating coil diameter, and the electric heating coil is held by the elastic force of the coil and the elastic force of the heat insulator. The electric heater structure according to claim 1, wherein the electric heating coil is fitted with an adhesive material and fixed to the groove. The electric heater structure according to claim 1 or 3, wherein a corrugated shape or a fine uneven shape is formed on an inner surface of the electric heating coil fitting groove, thereby holding the electric heating coil. A plate-like heat insulator formed into a plate shape from a slurry raw material prepared by adding an inorganic binder to an inorganic fiber communicates with a fitting groove portion of an electric heating coil into which an electric heating coil is fitted from one plate surface, and a fitting groove portion of the electric heating coil When forming a plurality of through-groove holes formed by cutting and forming a plurality of through-groove holes that release heat from the other plate surface to the outside, the groove width of the heat-dissipating groove part is set to the fitting groove part of the electric-heat coil. It is formed so as to be narrower than the groove width, and the communication portion of the fitting groove portion of the electric heating coil is formed in a curved shape in accordance with the shape of the electric heating coil, and the electric heating coil is arranged in contact with the communication portion. It said fitting to fitting groove portions of the heating coil, connected to lead terminals of the heating coil is fitted in each through-slot, electric heating coil fitting of the plate-like thermal insulation body Manufacturing method of the heating coil structure, characterized in that fixing by superimposing another plate heat insulator as lid on.

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