JP2021108256A - Ceramic heater - Google Patents

Abstract

To perform joining in a state where sagging of sealing material is suppressed when there is dimensional constraint on an inner diameter of a flange.SOLUTION: A ceramic heater 11 includes: a round rod or a cylindrical heater body 20 made of ceramic; and a first flange 40 that is provided in a cylindrical shape around an axis line AX of the heater body 20 and into which the heater body 20 is inserted. The first flange 40 is provided with a sealing material reservoir having a one side opening that opens to one side and a connecting section 49 having the other side opening that opens to the other side. In a state where the heater body 20 is arranged inside the sealing material reservoir and the connecting section 49, the first flange 40 and the heater body 20 are joined by the sealing material filled in the sealing material reservoir. At the end of the other side of the sealing material, a width narrow section is provided where a gap between an own inner peripheral surface and an outer peripheral surface of the heater body 20 is narrower than a distance L in a radial direction between the connecting section 49 and the outer peripheral surface of the heater body 20.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to, for example, a ceramic heater used in a warm water washing toilet seat, a fan heater, an electric water heater, a 24-hour bath, a soldering iron, a hair iron, a cogeneration system, and the like.

As a ceramic heater provided with a heater main body and a flange externally fitted to the heater main body, for example, those described in Japanese Patent No. 6174821 (Patent Document 1 below) are known. The flange has a cup shape having a concave portion recessed in the axial direction of the heater body, and the concave portion is filled with glass. The ceramic heater is integrally formed as a whole by joining the flange and the heater body with glass.

Japanese Patent No. 6174821

The inner diameter of the flange is preferably set so that the difference from the outer diameter of the heater body is, for example, a predetermined dimension or less in consideration of preventing the molten glass from dripping. However, the inner diameter of the flange may be determined by the configuration of the mating side pipe connected to the flange, in which case the difference from the outer diameter of the heater body may be larger than 1 mm. If the difference from the outer diameter of the heater body becomes large, it may not be possible to prevent the molten glass from dripping. That is, when there is a dimensional restriction on the inner diameter of the flange, it is difficult to perform the joining while suppressing the sagging of the sealing material such as glass.

The ceramic heater of the present disclosure includes a ceramic round bar-shaped or tubular heater main body, and a flange provided so as to form a tubular shape around the axis of the heater main body and into which the heater main body is inserted. The ceramic heater is provided with a sealing material reservoir having a one-sided opening that opens on one side and a connecting part that has an opening on the other side that opens on the other side. Is arranged inside the sealing material reservoir and the connecting portion, and the flange and the heater main body are joined by the sealing material filled in the sealing material reservoir, and the sealing is performed. At the other end of the stopper, the gap between its inner peripheral surface and the outer peripheral surface of the heater body is narrower than the radial distance between the connection portion and the outer peripheral surface of the heater body. It is a ceramic heater provided with a narrow portion.

According to the present disclosure, when there is a dimensional restriction on the inner diameter of the flange, the joining can be performed in a state where the sealing material is suppressed from sagging.

FIG. 1 is a front view of the ceramic heater of the first embodiment. FIG. 2 is a cross-sectional view showing the internal structure of the ceramic heater. FIG. 3 is an enlarged cross-sectional view showing the joint portion of the first flange of FIG. FIG. 4 is a perspective view of the first flange. FIG. 5 is a plan view of the first flange. FIG. 6 is a perspective view showing how the ceramic sheet is wound around the outer peripheral surface of the ceramic tube and adhered. FIG. 7 is a perspective view showing how each flange and the heater main body are joined by glass. FIG. 8 is an enlarged cross-sectional view showing the joint portion of the first flange of the second embodiment. FIG. 9 is an enlarged cross-sectional view showing the joint portion of the first flange of the third embodiment.

[Explanation of Embodiments of the present disclosure]
First, embodiments of the present disclosure will be listed and described.
(1) The ceramic heater of the present disclosure includes a ceramic round bar-shaped or tubular heater main body and a flange provided so as to form a tubular shape around the axis of the heater main body and into which the heater main body is inserted. A ceramic heater comprising, the flange comprising a sealing material reservoir having a one-sided opening that opens on one side and a connecting portion that has an opening on the other side that opens to the other side. In a state where the heater main body is arranged inside the sealing material reservoir and the connecting portion, the flange and the heater main body are joined by the sealing material filled in the sealing material reservoir. At the other end of the sealing material, the gap between its inner peripheral surface and the outer peripheral surface of the heater body is the radial distance between the connection portion and the outer peripheral surface of the heater body. It is a ceramic heater provided with a narrower portion.

When joining the flange and the heater body, the molten encapsulant is filled into the encapsulant reservoir through the opening on one side, and the encapsulant cools and hardens to complete the joining. Even if the difference between the inner diameter of the flange and the outer diameter of the heater body is large during filling, the gap between the inner peripheral surface of the narrow portion and the outer peripheral surface of the heater body is between the connection portion and the outer peripheral surface of the heater body. Since it is narrower than the radial distance of, it is possible to prevent the sealing material filled in the sealing material reservoir from dripping to the other side.

(2) The flange has a large diameter portion constituting the sealing material reservoir portion and a small diameter portion having a smaller diameter than the large diameter portion and forming the connecting portion, and forming a stepped shape with the small diameter portion. It is preferable to have a connecting portion for connecting the portion and the large diameter portion.
It is known that when the encapsulant is cooled, one side of the encapsulant tries to increase the diameter with the other side of the encapsulant as a fulcrum, and tensile stress is generated on one side of the encapsulant. According to the above configuration, since the encapsulant reservoir is composed of a large diameter portion, the tensile stress can be dispersed in a wide range as compared with the case where the encapsulant reservoir is composed of a small diameter portion. can. Therefore, it is possible to prevent cracks from entering the sealing material.

(3) It is preferable that a spacer supported by the flange is arranged inside the flange with the heater body inserted inside the self-confidence, and the narrow portion is the spacer.
When the narrow portion is integrally formed with the flange, the flange becomes thick and distorted at the position of the narrow portion, so that stress is likely to be generated when the sealing material is cooled. In addition, since the narrow portion cannot be processed by press working, it is disadvantageous in terms of manufacturing cost. In that respect, since the narrow portion is formed separately from the flange, it is possible to prevent the flange from having a distorted shape, and the narrow portion can be manufactured by press working.

(4) The flange is preferably made of metal.
When the flange is made of metal, the flange can be formed by pressing a metal flat plate, so that the manufacturing cost of the flange can be reduced.

(5) It is preferable that the thickness of the inner wall constituting the sealing material reservoir is constant.
When the thickness of the inner wall constituting the encapsulant reservoir is not constant, that is, the shape of the encapsulant reservoir is distorted, stress is likely to occur when the encapsulant is cooled. On the other hand, if the thickness of the inner wall constituting the encapsulant reservoir is constant, stress is less likely to be generated when the encapsulant is cooled, and for example, the encapsulant can be prevented from cracking.

[Details of Embodiment 1 of the present disclosure]
Specific examples of the ceramic heater of the present disclosure will be described below with reference to the drawings. It should be noted that the present disclosure is not limited to these examples, and is indicated by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

<Overall configuration of ceramic heater>
The ceramic heater 11 of the first embodiment is a heater for liquid heating used for a warm water washing toilet seat, a 24-hour bath, hand washing, cogeneration and the like. As shown in FIGS. 1 and 2, the ceramic heater 11 includes a cylindrical ceramic heater main body 20, a metal annular second flange 30 into which the heater main body 20 is inserted, and a second flange. A first flange 40 arranged below the 30 is provided.

<Heater body>
The heater main body 20 is provided so as to form a cylindrical shape with the axis AX as the center. The heater main body 20 includes a ceramic tube 21 and a ceramic layer 22 that covers almost the entire outer circumference of the ceramic tube 21. Since the ceramic layer 22 does not completely cover the outer periphery of the ceramic tube 21, a groove portion 24 extending in the axial direction (direction parallel to the direction in which the axis AX extends) is formed on the outer peripheral surface 23 of the heater main body 20. ..

The ceramic tube 21 and the ceramic layer 22 constituting the heater main body 20 are made of, for example, alumina. The thermal expansion coefficient of the alumina is in the range of ^{50 × 10 -7 / K~90 × 10} -7 / K, those of the present embodiment is a ^{70 × 10 -7 / K (30} ℃ ~380 ℃) It has become.

As shown in FIG. 6, a meandering pattern-shaped heater pattern layer 25 and a pair of internal terminals 26 are formed on the inner peripheral surface (the surface on the ceramic tube 21 side) or the inside of the ceramic layer 22. These internal terminals 26 are electrically connected to the external terminals 27 at the ends of the outer peripheral surface of the ceramic layer 22 via via conductors (not shown) or the like.

<Second flange>
The second flange 30 is, for example, an annular member made of a metal such as stainless steel, and is provided so as to form a tubular shape around the axis AX as shown in FIG. The second flange 30 is formed in a concave shape (cup shape) by, for example, pressing the central portion of the metal plate material downward by press working. In detail, the second flange 30 has a stepped shape with a large-diameter portion 31 that opens upward and a small-diameter portion 32 that is arranged below the large-diameter portion 31 and has a smaller diameter than the large-diameter portion 31. It is configured to include a connecting portion 33 that connects the large diameter portion 31 and the small diameter portion 32. A hole 34 is formed in the central portion of the bottom surface of the small diameter portion 32. The hole portion 34 has a form of penetrating the bottom surface of the small diameter portion 32 in the vertical direction.

Thermal expansion coefficient of the metal forming the second flange 30 is a value within the range of ^{100 × 10 -7 / K~200 × 10} -7 / K. For example, when the second flange 30 is made of SUS304 (main components are Fe, Ni, Cr), its coefficient of thermal expansion is 178 × ^10-7 / K (30 ° C to 380 ° C), and SUS430 ( When the main components are made of Fe, Cr), the coefficient of thermal expansion is 110 × 10 ^-7 / K (30 ° C to 380 ° C).

The inside of the small diameter portion 32 of the second flange 30 is a glass reservoir 37 filled with the glass 36. The second flange 30 and the heater body 20 are integrally joined by the glass 36. As the glass 36, for example, Na ₂ O ・ Al ₂ O ₃・ B ₂ O ₃・ SiO ₂ type glass, so-called Al ₂ O ₃・ B ₂ O ₃・ SiO ₂ type glass (borosilicate glass) is used. Has been done. The coefficient of thermal expansion of the glass 36 is, for example, ^{a value in the range of 50 × 10 -7} / K to 90 × 10 ^-7 / K (30 ° C to 380 ° C), and 62 × 10 ^-7 / in the present embodiment. It is K (30 ° C to 380 ° C).

For example, there is a narrow gap of about 0.1 mm to 1.0 mm between the hole edge of the hole 34 and the outer peripheral surface 23 of the heater main body 20, and in the present embodiment, the dimension of the narrow gap is 0.3 mm. It is set to about 0.5 mm.

<1st flange>
The first flange 40 is, for example, an annular member made of a metal such as stainless steel, and is provided so as to form a tubular shape around the axis AX as shown in FIG. The first flange 40 is manufactured by, for example, forming a stepped bottomed cylinder by pushing a metal material as a base material downward by press working, and then punching the bottom surface. The first flange 40 has a form of penetrating in the vertical direction as a whole, and more specifically, it has a large diameter portion 41 that opens upward and a large diameter portion 41 that is arranged below the large diameter portion 41 and has a smaller diameter than the large diameter portion 41. It is configured to include a small diameter portion 42 and a connecting portion 43 that connects the large diameter portion 41 and the small diameter portion 42 in a stepped shape.

The large diameter portion 41 has an upper opening 44 that opens upward, and the small diameter portion 42 has a lower opening 45 that opens downward. The small diameter portion 42 constitutes a connecting portion 49 connected to a mating side pipe (not shown). The mating side pipe is a pipe for supplying water, and the water that has entered the inside of the heater main body 20 from the mating side pipe through the lower opening 45 of the first flange 40 is heated.

The first flange 40 is fitted onto the lower end of the heater body 20. The lower end of the heater main body 20 is located at the upper end of the small diameter portion 42 of the first flange 40, and the heater main body 20 is arranged to penetrate the large diameter portion 41 and the connecting portion 43 in the vertical direction. Inside the first flange 40, a glass reservoir 47 filled with glass 46 is provided. The glass pool portion 47 is a space filled with glass 46. Specifically, the outer peripheral surface of the heater main body 20 and the inner peripheral surface of the first flange 40 from the large diameter portion 41 to the connecting portion 43. It is a space surrounded by the spacer 50, which will be described later.

The first flange 40 and the heater main body 20 are integrally joined by the glass 46 in a state where the heater main body 20 is arranged inside the glass reservoir 37 and the connection portion 49. As the glass 46, for example, Na ₂ O ・ Al ₂ O ₃・ B ₂ O ₃・ SiO ₂ type glass, so-called Al ₂ O ₃・ B ₂ O ₃・ SiO ₂ type glass (borosilicate glass) is used. Has been done. The coefficient of thermal expansion of the glass 46 is, for example, ^{a value in the range of 50 × 10 -7} / K to 90 × 10 ^-7 / K (30 ° C to 380 ° C), and is 62 × 10 ^-7 / in the present embodiment. It is K (30 ° C to 380 ° C).

Of the inner walls constituting the glass reservoir 47, the thickness T of the inner wall formed by the first flange 40 is constant. The thickness T is, for example, 0.8 ± 0.1 mm. When the thickness T is constant, stress is less likely to be generated when the glass 46 is cooled, and the glass 46 can be prevented from breaking.

By the way, the lower end of the inner wall constituting the glass reservoir 47 is formed by the spacer 50. As shown in FIGS. 4 and 5, the spacer 50 includes a cylindrical portion 51 that has a cylindrical shape and extends in the vertical direction, and a flange portion 52 that projects radially outward from the upper edge of the tubular portion 51. It is composed of. As shown in FIG. 3, the inner peripheral surface of the tubular portion 51 is arranged along the outer peripheral surface of the heater main body 20.

The outer diameter of the heater main body 20 is, for example, 10.4 ± 0.3 mm, and the inner diameter of the small diameter portion 42 of the first flange 40 is, for example, 13.05 ± 0.05 mm. Therefore, the radial distance L between the outer peripheral surface of the heater main body 20 and the inner peripheral surface of the small diameter portion 42 of the first flange 40 is 1.15 to 1.5 mm (one side). If the distance L is larger than 1 mm, the glass 46 may hang down on the lower side of the first flange 40. Therefore, in the present embodiment, the spacer 50 is arranged in the gap G to suppress the sagging of the glass 46.

The spacer 50 is formed separately from the first flange 40, is inserted into the glass reservoir 47 from the upper opening 44, and is arranged on the first flange 40 by hooking the flange 52 on the connecting portion 43. Most of the gap G is closed by the spacer 50, leaving only a narrow gap S1 between the outer peripheral surface of the heater main body 20 and the inner peripheral surface of the tubular portion 51 of the spacer 50. The dimension of this narrow gap S1 is, for example, 0 to 0.35 mm (one side). Further, since the flange portion 52 is arranged in contact with the upper surface of the connecting portion 43, there is almost no gap between the flange portion 52 and the upper surface of the connecting portion 43. At the lower end of the glass 46, the spacer 50 is arranged so that the narrow gap S1 is narrower than the radial distance L1. As a result, it is possible to prevent the glass 46 filled in the glass reservoir 47 from hanging down below the first flange 40. In order to suppress the sagging of the glass 46, it is preferable that the dimension of the narrow gap S1 is 0.5 mm or less (one side).

<Ceramic heater manufacturing method>
Next, a method of manufacturing the ceramic heater 11 will be described with reference to FIGS. 6 and 7.
First, as shown in FIG. 6, the cylindrical alumina-based ceramic tube 21 is tentatively fired. Separately, a refractory metal such as tungsten is printed on the surface of the alumina-based ceramic sheet 60 or on the inside of the laminated sheet. As a result, the pattern 61 which later becomes the heater pattern layer 25, the internal terminal 26, and the external terminal 27 is formed.

Next, a ceramic paste (alumina paste) is applied to one side surface of the ceramic sheet 60, and as shown in the left figure of FIG. 6, the ceramic sheet 60 is wound around the outer peripheral surface of the ceramic tube 21 and adhered, and then integrally fired. do. After that, the external terminal 27 is nickel-plated to form the heater body 20. As a result, as shown in the right figure of FIG. 6, only the external terminals 27 are arranged in a state of being exposed to the outside.

Next, as shown in the left figure of FIG. 7, the first flange 40 and the second flange 30 are fitted outside at predetermined height positions of the heater main body 20, and in this state, the flanges 30, 40 and the heater main body 20 are fitted. Support with a jig (not shown). When the first flange 40 is externally fitted to the heater main body 20, the flange portion 52 of the spacer 50 is preliminarily arranged on the upper surface of the connecting portion 43 of the first flange 40, and from that state, the tubular portion of the spacer 50 is placed. The 51 is fitted onto the lower end of the heater body 20. As a result, the gap G formed between the outer peripheral surface of the heater main body 20 and the inner peripheral surface of the first flange 40 is almost closed by the spacer 50.

Next, a glass material made of borosilicate glass is press-molded into a ring shape and calcined at 640 ° C. for 30 minutes to prepare calcined glass materials 38 and 48 in advance. As shown in the above, ring-shaped calcined glass materials 38 and 48 are arranged in the glass reservoirs 37 and 47 between the heater main body 20 and the flanges 30 and 40.

Next, the one in this state is put into a continuous furnace for firing, and the heater main body 20 and the flanges 30 and 40 are attached to glass. Specifically, the calcined glass materials 38 and 48 are melted by heating the continuous furnace in a reducing atmosphere (for example, N ₂ + 5% H ₂ ) at a welding temperature (1015 ° C.) for a predetermined time. After that, the calcined glass materials 38 and 48 are cooled to room temperature (for example, 25 ° C.) and solidified to solidify the heater main body 20 and each flange 30 via the glass 36 and 46 as shown in the right figure of FIG. , 40 are welded and fixed to complete the ceramic heater 11.

<Effect of Embodiment 1>
According to the ceramic heater 11 of the present embodiment, when the first flange 40 and the heater main body 20 are joined, the molten glass 46 is filled into the glass reservoir 47 from the upper opening 44, and the glass 46 cools and hardens. Joining is completed with. Even if the difference between the inner diameter of the first flange 40 and the outer diameter of the heater body 20 is large during filling, the narrow gap S1 which is the gap between the inner peripheral surface of the spacer 50 and the outer peripheral surface of the heater body 20 is the connecting portion. Since the distance L in the radial direction between the 49 and the outer peripheral surface of the heater main body 20 is smaller than the radial distance L, it is possible to prevent the glass 46 filled in the glass reservoir 47 from hanging downward.

The first flange 40 has a large diameter portion 41 forming a glass reservoir 47, a small diameter portion 42 having a smaller diameter than the large diameter portion 41, and a small diameter portion 42 forming a connecting portion 49, and a small diameter portion 42 having a stepped shape. It is preferable to have a connecting portion 43 for connecting the large diameter portion 41 and the large diameter portion 41. It is known that when the glass 46 is cooled, the upper side of the glass 46 tries to increase its diameter with the lower side of the glass 46 as a fulcrum, and tensile stress is generated on the upper side of the glass 46. According to the above configuration, since the glass reservoir 47 is composed of the large diameter portion 41, the tensile stress can be dispersed in a wide range as compared with the case where the glass reservoir 47 is composed of the small diameter portion 42. can. Therefore, it is possible to prevent the glass 46 from cracking.

It is preferable that a spacer 50 supported by the first flange 40 is arranged inside the first flange 40 with the heater main body 20 inserted inside the self-confidence. When the narrow portion is integrally formed with the first flange 40 instead of the spacer 50, the first flange 40 becomes thick and distorted at the position of the narrow portion, so that stress is likely to be generated when the glass is cooled. .. In addition, since the narrow portion cannot be processed by press working, it is disadvantageous in terms of manufacturing cost. In that respect, since the spacer 50 as the narrow portion is formed separately from the first flange 40, it is possible to prevent the first flange 40 from having a distorted shape, and the spacer 50 can be manufactured by press working.

The first flange 40 is preferably made of metal. When the first flange 40 is made of metal, the first flange 40 can be formed by pressing a metal flat plate, so that the manufacturing cost of the first flange 40 can be reduced.

It is preferable that the thickness T of the inner wall constituting the glass reservoir 47 is constant. When the thickness T of the inner wall constituting the glass reservoir 47 is not constant, that is, when the shape of the glass reservoir 47 is distorted, stress is likely to be generated when the glass 46 is cooled. In that respect, if the thickness T of the inner wall constituting the glass reservoir 47 is constant, stress is less likely to be generated when the glass 46 is cooled, and for example, the glass 46 can be prevented from breaking.

[Details of Embodiment 2 of the present disclosure]
Next, the second embodiment will be described with reference to FIG. The ceramic heater 12 of the second embodiment is a partial modification of the configuration of the first flange 40 of the ceramic heater 11 of the first embodiment, and the other configurations are the same as those of the first embodiment. Omit. Further, for the same configuration as that of the first embodiment, the same reference numerals as those of the first embodiment shall be used.

The first flange 70 of the present embodiment has a stepped shape with a large diameter portion 71 that opens upward and a small diameter portion 72 that is arranged below the large diameter portion 71 and has a smaller diameter than the large diameter portion 71. A connecting portion 73 for connecting the large diameter portion 71 and the small diameter portion 72 is provided. The large diameter portion 71 has an upper opening 74 that opens upward, and the small diameter portion 72 has a lower opening 75 that opens downward.

The small diameter portion 72 constitutes a connecting portion 79 connected to a mating side pipe (not shown). The mating side pipe is a pipe for supplying water, and the water that has entered the inside of the heater main body 20 from the mating side pipe through the first flange 70 is heated.

Inside the first flange 70, a glass reservoir 77 filled with glass 76 is provided. The glass pool portion 77 is a space filled with glass 76. Specifically, the outer peripheral surface of the heater main body 20 and the inner peripheral surface of the first flange 70 from the large diameter portion 71 to the connecting portion 73. It is a space surrounded by the narrow portion 78 described below.

A narrow portion 78 is provided at the lower end of the glass 76. The narrow portion 78 is provided on the inner peripheral side of the upper end portion of the small diameter portion 72. The narrow portion 78 is integrally formed with the small diameter portion 72, has a form of protruding inward in the radial direction from the inner peripheral surface of the small diameter portion 72, and is provided in an annular shape centered on the axis AX. The inner peripheral surface of the narrow portion 78 is formed to extend in the vertical direction along the outer peripheral surface of the heater main body 20.

A narrow gap S2 is formed between the outer peripheral surface of the heater main body 20 and the inner peripheral surface of the narrow portion 78. The dimension of this narrow gap S2 is, for example, 0 to 0.35 mm (one side). As a result, it is possible to prevent the glass 76 filled in the glass reservoir 77 from hanging down below the first flange 70.

[Details of Embodiment 3 of the present disclosure]
Next, the third embodiment will be described with reference to FIG. The ceramic heater 13 of the third embodiment is a partial modification of the configuration of the first flange 40 of the ceramic heater 11 of the first embodiment, and the other configurations are the same as those of the first embodiment. Omit. Further, for the same configuration as that of the first embodiment, the same reference numerals as those of the first embodiment shall be used.

Unlike the first flange 40 of the first embodiment, the first flange 80 of the present embodiment does not have a large diameter portion and a connecting portion, and is composed of only a small diameter portion 82. Therefore, the first flange 80 has a cylindrical shape as a whole. The small diameter portion 82 has an upper opening 84 that opens upward and a lower opening 85 that opens downward.

The lower end side of the small diameter portion 82 constitutes a connecting portion 89 connected to a mating side pipe (not shown). The mating side pipe is a pipe for supplying water, and the water that has entered the inside of the heater main body 20 from the mating side pipe through the lower opening 85 is heated.

A glass reservoir 87 filled with glass 86 is provided inside the upper end side of the small diameter portion 82. The glass pool portion 87 is a space filled with the glass 86, and includes an outer peripheral surface of the heater main body 20, an inner peripheral surface of the small diameter portion 82 of the first flange 80, and an upper surface of the spacer 90 described below. It is a space surrounded by.

A gap G is formed between the outer peripheral surface at the lower end of the heater main body 20 and the inner peripheral surface of the small diameter portion 82, and the spacer 90 is arranged in this gap G. The spacer 90 of the present embodiment is configured separately from the small diameter portion 82, and is arranged at the lower end portion of the glass 86. Although the outer diameter of the spacer 90 is smaller than the outer diameter of the spacer 50 of the first embodiment, the inner diameter of the spacer 90 is the same as the inner diameter of the spacer 50 of the first embodiment.

A narrow gap S3 is formed between the outer peripheral surface of the heater main body 20 and the inner peripheral surface of the spacer 90. The dimension of this narrow gap S3 is, for example, 0 to 0.35 mm (one side). The spacer 90 is held, for example, by press fitting into the first flange 80, and the outer peripheral edge portion 91 of the spacer 90 is in contact with the inner peripheral surface of the small diameter portion 82 over the entire circumference. As a result, it is possible to prevent the glass 86 filled in the glass reservoir 87 from hanging down below the first flange 90.

<Other Embodiments>
(1) Although the cylindrical heater main body 20 is illustrated in the first to third embodiments, it may be a cylindrical heater main body or a round bar-shaped heater main body.

(2) In the first to third embodiments, although glass is used as the sealing material, an epoxy-based sealing material, a ceramic-based sealing material, or the like may be used.

(3) Although the spacer 50 is arranged in the connecting portion 43 in the first embodiment, the spacer 90 of the third embodiment may be used to hold the spacer 50 in the small diameter portion 42.

(4) In the first to third embodiments, although the first flange is made of metal, the first flange may be made of ceramic.

(5) In the first and third embodiments, although the tubular spacers 50 and 90 that are seamlessly connected in the circumferential direction in the plan view are used, the tubular spacers that are C-shaped and have a cut in the plan view are used. You may use it.

11 ... Ceramic heater 20 ... Heater body, 21 ... Ceramic tube, 22 ... Ceramic layer, 23 ... Outer surface, 24 ... Groove, 25 ... Heater pattern layer, 26 ... Internal terminal, 27 ... External terminal 30 ... Second flange, 31 ... Large diameter part, 32 ... Small diameter part, 33 ... Connecting part, 34 ... Hole part, 36 ... Glass, 37 ... Glass pool, 38 ... Temporarily baked glass material 40 ... First flange (flange), 41 ... Large diameter Part, 42 ... Small diameter part, 43 ... Connecting part, 44 ... Upper opening (one side opening), 45 ... Lower opening (other side opening), 46 ... Glass (sealing material), 47 ... Glass pool Part (sealing material reservoir), 48 ... Temporarily baked glass material, 49 ... Connection part 50 ... Spacer (narrow part), 51 ... Cylindrical part, 52 ... Flange part 60 ... Ceramic sheet, 61 ... Pattern 70 ... 1st flange (flange), 72 ... Large diameter part, 73 ... Small diameter part, 73 ... Connecting part, 74 ... Upper opening (one side opening), 75 ... Lower opening (other side opening), 76 ... Glass (encapsulating material), 77 ... Glass reservoir, 78 ... Narrow part, 79 ... Connection part 80 ... First flange (flange), 82 ... Small diameter part, 84 ... Upper opening, 85 ... Lower opening, 86 ... Glass, 87 ... Glass pool, 89 ... Connection 90 ... Spacer (narrow part), 91 ... Outer peripheral edge AX ... Axis G ... Gap, L ... Distance, S1 ... Narrow gap, S2 ... Narrow gap, S3 ... narrow gap, T ... thickness

Claims (5)

With a ceramic round bar or tubular heater body,
A ceramic heater provided with a tubular shape around the axis of the heater body and having a flange into which the heater body is inserted.
The flange comprises a sealing material reservoir having a one-sided opening that opens on one side and a connecting portion that has another side opening that opens on the other side.
The flange and the heater body are joined by the sealing material filled in the sealing material reservoir in a state where the heater main body is arranged inside the sealing material reservoir and the connecting portion. ,
At the other end of the encapsulant, the gap between its inner peripheral surface and the outer peripheral surface of the heater body is greater than the radial distance between the connection and the outer peripheral surface of the heater body. A ceramic heater with a narrow narrow part. The flange has a large diameter portion constituting the encapsulant pool portion, a small diameter portion having a smaller diameter than the large diameter portion, and a small diameter portion constituting the connecting portion, and forming a stepped shape with the small diameter portion and the flange. The ceramic heater according to claim 1, further comprising a connecting portion for connecting a large diameter portion. Inside the flange, a spacer supported by the flange is arranged with the heater body inserted inside the flange.
The ceramic heater according to claim 1 or 2, wherein the narrow portion is the spacer. The ceramic heater according to any one of claims 1 to 3, wherein the flange is made of metal. The ceramic heater according to any one of claims 1 to 4, wherein the thickness of the inner wall constituting the sealing material reservoir is constant.

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