Ceramic heater

Abstract

To provide a ceramic heater which can reliably seal and connect between a flange and a heater body with the use of a sealing material, and which can also be downsized.SOLUTION: A ceramic heater 11 comprises: a rod-like or cylindrical heater body 20 which is made of ceramic; and a flange 30 which is provided around an axis line L of the heater body such that it forms a cylindrical shape, and into which the heater body is inserted. The flange is formed by coupling together, along the axis line, a plate-like part 31 and a cylindrical part 32 which are separate members. The plate-like part has an insertion hole for the heater body, and the cylindrical part surrounds the heater body and extends in an axial direction along an outer surface of the heater body. The plate-like part protrudes further outward in the radial direction than the cylindrical part. The flange and the heater body are bonded together with a sealing material 40 filled in a region R surrounded by the plate-like part, cylindrical part, and the outer surface of the heater body.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a ceramic heater used in, for example, warm-water washing toilet seats, fan heaters, electric water heaters, 24-hour baths, soldering irons, hair irons, etc. [Background technology]

[0002] Conventionally, for example, a warm water washing toilet seat uses a heat exchange unit having a resin container (heat exchanger), and a long pipe-shaped ceramic heater is arranged in this heat exchange unit to warm the washing water contained in the heat exchanger. This ceramic heater comprises a rod-shaped or cylindrical heater body and a flange fitted onto the heater body, and the flange is adapted to be attached to a predetermined portion of a vessel (heat exchanger) to which it is to be attached.

[0003] A sealing material such as glass is filled into the gap between the flange and the outer surface of the heater body, and the flange and the heater body are joined together. Various developments have been made to ensure that molten glass can be stably poured into the gap between the flange and the heater body. For example, a technique is known in which a flange is provided with a sealant reservoir and a narrow width portion is arranged to suppress dripping of the sealant (see Patent Document 1). In addition, a technology is known in which a cylindrical portion extending along the side of the heater body is connected to a metal disk-shaped flange portion (support member), thereby making the distance between the heater body and the cylindrical portion constant and making the thickness of the glass filled in this gap uniform, thereby suppressing stress imbalance due to differences in thermal expansion and improving durability (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-108256 [Patent Document 2] JP 2019-133762 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when providing a sealant reservoir in a flange, it may be difficult to reduce the diameter and size of the flange because the sealant reservoir is formed in a cup shape. Also, there is a risk of an increase in the number of steps, such as press working, for forming a metal or the like into a cup shape. Furthermore, when a disk-shaped flange portion and a cylindrical portion are connected together as in the technology of Patent Document 2, molten glass is poured into an opening in the cylindrical portion on the axially opposite side to the flange portion. However, air remaining in the corners between the flange portion and the cylindrical portion is not expelled, preventing glass from flowing into the corners, which may reduce the airtightness and strength near the corners.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a ceramic heater in which the flange and the heater body can be reliably sealed and connected with a sealant and which can also be made compact. [Means for solving the problem]

[0007] In order to solve the above problems, the ceramic heater of the present invention is a ceramic heater comprising a rod-shaped or cylindrical heater body made of ceramic, and a flange arranged in a cylindrical shape around the axis of the heater body and into which the heater body is inserted, wherein the flange is a separate member and comprises a plate-shaped portion having an insertion hole for the heater body and a cylindrical portion surrounding the heater body and extending in the axial direction along the outer surface of the heater body, joined together along the axis, the plate-shaped portion protruding radially outward beyond the cylindrical portion, and a sealant is filled in the area surrounded by the plate-shaped portion, the cylindrical portion, and the outer surface of the heater body, and the flange and the heater body are joined together.

[0008] In this ceramic heater, the plate-like portion and the cylindrical portion that constitute the flange are separate bodies, so when the plate-like portion and the cylindrical portion are arranged before filling with the sealing material, a gap is inevitably generated between them. When the liquid (molten) sealant is poured into the above-mentioned region, the air remaining in the corners between the plate-like portion and the cylindrical portion is expelled through the gap, making it easier for the sealant to flow into the corners. As a result, the reduction in airtightness and strength near the corners is suppressed, and the flange and heater body can be reliably sealed and connected with the sealant. In addition, because the plate-like portion protrudes radially outward from the cylindrical portion, when the plate-like portion and the cylindrical portion, which are separate bodies, are arranged, the outer edge of the plate-like portion is reliably positioned radially outward from the cylindrical portion. Therefore, no gap is generated between the outer edge of the plate-like portion and the cylindrical portion, and when liquid (molten) sealing material is poured into the above-mentioned region, the sealing material can be prevented from flowing out (in the direction of the surface of the plate-like portion) from this gap. Furthermore, by reducing the diameter of the cylindrical portion, the flange, and therefore the ceramic heater, can be made smaller.

[0009] In the ceramic heater of the present invention, the plate-shaped portion and the cylindrical portion may be fixed to each other by the sealing material. According to this ceramic heater, the flange and the heater body can be more reliably sealed and connected with the sealing material.

[0010] In the ceramic heater of the present invention, a gap may be formed between the plate-like portion and the cylindrical portion, and the gap may be filled with the plug material. According to this ceramic heater, the plate-shaped portion and the cylindrical portion can be fixed more firmly.

[0011] In the ceramic heater of the present invention, the sealing material does not need to be interposed beyond the plate-like portion on the side opposite to the cylindrical portion along the axis. According to this ceramic heater, it is possible to prevent the sealing material from protruding beyond the plate-like portion and interfering with other components (for example, a heat exchanger to which the heater is attached).

[0012] In the ceramic heater of the present invention, the sealing material may be interposed beyond the plate-like portion on the opposite side to the cylindrical portion along the axis. According to this ceramic heater, the flange and the heater body can be fixed more firmly.

[0013] In the ceramic heater of the present invention, when the maximum radial distance between the outer surface of the heater body and the inner surface of the cylindrical portion is D1, and the maximum radial distance between the outer surface of the cylindrical portion and the outer edge of the plate-like portion is D2, D1 > D2 may be satisfied. According to this ceramic heater, the diameter of the flange can be reduced, and thus the flange, and by extension, the ceramic heater can be made more compact.

[0014] In the ceramic heater of the present invention, when the maximum radial distance between the outer surface of the heater body and the inner surface of the cylindrical portion is D1, and the maximum radial distance between the outer surface of the cylindrical portion and the outer edge of the plate-like portion is D2, D1 < D2 may be satisfied. In a ceramic heater, the plate-like portion protruding outward from the cylindrical portion is fixed to the heat exchanger by being sandwiched vertically (in the axial direction) by the fixing portion on the heat exchanger side, which is the object to be fixed. Therefore, the larger the diameter of the plate-like portion serving as a flange, in other words, the smaller D1 < D2 is, the more firmly it can be fixed to the object to be fixed.

[0015] In the ceramic heater of the present invention, an extension portion that extends toward the cylindrical portion and serves as a guide to the outer surface of the heater body may be provided on the inner surface of the plate-like portion. According to this ceramic heater, it becomes easier to position the plate-like portion when inserting and arranging it on the heater body.

[0016] The sealing material may be glass. Glass can easily enter the gap between the plate-like portion and the cylindrical portion in a liquid state and seal it.

Advantages of the Invention

[0017] According to this invention, a ceramic heater that can reliably seal and connect the flange and the heater body with a sealing material and can also be miniaturized can be obtained.

Brief Description of the Drawings

[0018] [Figure 1] FIG. 1 is a front view showing a ceramic heater according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing a configuration of a heater main body. [Diagram 3] 2 is a cross-sectional view taken along the plane of the paper in FIG. 1. [Figure 4] 13A and 13B are diagrams showing modified examples of the flange of the ceramic heater according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing a ceramic heater 11 according to an embodiment of the present invention, FIG. 2 is a perspective view showing the configuration of a heater body 20, and FIG. 3 is a cross-sectional view taken along the plane of FIG. The ceramic heater 11 according to the embodiment of the present invention can be used, for example, in a heat exchanger of a heat exchange unit of a warm-water washing toilet seat to heat washing water.

[0020] As shown in FIG. 1, the ceramic heater 11 includes a ceramic heater body 20 and a flange 30 that is provided in a cylindrical shape around the axis L of the heater body 20 and into which the heater body 20 is inserted.

[0021] The heater body 20 is provided in this example so as to have a cylindrical shape centered on an axis L. The heater body 20 includes a ceramic tube 21 and a ceramic layer (ceramic sheet) 22 that covers almost the entire outer periphery of the ceramic tube 21. Since the ceramic layer 22 does not completely cover the outer periphery of the ceramic tube 21, the outer periphery of the heater body 20 has slits 22s formed therein, which extend in the axial direction (parallel to the direction in which the axis L extends).

[0022] 2, a heater pattern layer 25 having a meandering pattern and a pair of internal terminals 26 are formed on the inner peripheral surface (the surface on the ceramic tube 21 side) or inside of the ceramic layer 22. These internal terminals 26 are electrically connected to external terminals 27 at the ends of the outer peripheral surface of the ceramic layer 22 through via conductors or the like (not shown). The heater pattern layer 25 is disposed near the tip 20 a of the heater body 20 , and the external terminal 27 is disposed on the rear end side of the heater body 20 .

[0023] In this example, the ceramic tube 21 is cylindrical and has a through hole 21h in the direction of its axis O. In the heat exchanger, the water flowing inside the through hole 21h is heated by the ceramic heater 11, and further, the water in the gap between the inner wall of the heat exchanger and the outer periphery of the ceramic heater is also heated by the ceramic heater 11. The ceramic tube 21 and ceramic layer 22 may be formed, for example, from alumina.

[0024] Next, the flange 30 will be described. As shown in FIG. 1, the flange 30 is disposed on the rear end side of the heater body 20 and closer to the front end side than the external terminal 27 . The flange 30 is a separate member and has a plate-like portion 31 having an insertion hole for the heater body 20, and a cylindrical portion 32 surrounding the heater body 20 and extending in the direction of the axis L along the outer surface of the heater body 20. The flange 30 is formed by joining the plate-like portion 31 and the cylindrical portion 32 along the axis L. The plate-like portion 31 and the cylindrical portion 32 are made of a metal such as stainless steel. In this embodiment, the cylindrical portion 32 is disposed closer to the tip end than the plate-like portion 31, but the positional relationship may be reversed.

[0025] FIG. 3 is a cross-sectional view taken along the plane of the paper in FIG. As shown in FIG. 3, the plate-like portion 31 protrudes radially outward beyond the cylindrical portion 32 . Furthermore, a sealing material (glass) 40 is filled in a region R surrounded by the plate-like portion 31, the cylindrical portion 32, and the outer surface of the heater body 20 (ceramic layer 22), and the flange 30 and the heater body 20 are joined together.

[0026] Here, since the plate-shaped portion 31 and the tubular portion 32 that constitute the flange 30 are separate bodies, when the plate-shaped portion 31 and the tubular portion 32 are positioned before the glass 40 is filled, a gap G1 is inevitably generated between the two. When liquid (molten) glass 40 is poured into the region R, the air remaining in the corner RC between the plate-like portion 31 and the cylindrical portion 32 is discharged through the gap G1, making it easier for the glass 40 to flow into the corner RC. As a result, the reduction in airtightness and strength near the corner RC is suppressed, and the flange 30 and the heater body 20 can be reliably sealed and connected with the glass 40. On the other hand, for example, if the plate-shaped portion 31 and the tubular portion 32 are integrated by welding or the like before pouring in the glass 40, the gap G1 does not occur, and therefore, the air remaining in the corner RC when the glass 40 is poured in is not expelled, and the glass may not flow into the corner RC.

[0027] In addition, because the plate-shaped portion 31 protrudes radially outward beyond the cylindrical portion 32, when the plate-shaped portion 31 and the cylindrical portion 32, which are separate bodies, are arranged, the outer edge 31e of the plate-shaped portion 31 is reliably positioned radially outward beyond the cylindrical portion 32. Therefore, no gap is generated between the outer edge 31e of the plate-shaped portion 31 and the cylindrical portion 32, and when liquid (molten) glass 40 is poured into the region R, it is possible to prevent the glass 40 from flowing out (in the surface direction of the plate-shaped portion 31) from this gap. Furthermore, by reducing the diameter of the cylindrical portion 32, the flange 30, and therefore the ceramic heater 11, can be made smaller in size.

[0028] Whether the plate-shaped portion 31 and the cylindrical portion 32 are separate can be determined by whether the plate-shaped portion 31 and the cylindrical portion 32 are separated when the sealing material (glass) is remelted. The sealing material is preferably glass, but resin adhesives and metal brazing materials (silver brazing, etc.) can also be used.

[0029] The region R is filled with glass 40, so that the plate-shaped portion 31 and the cylindrical portion 32 are fixed to each other by the glass 40 (through the glass 40). Furthermore, in this example, the gap G1 between the plate-shaped portion 31 and the cylindrical portion 32 is also filled with glass 40. This makes it possible to fix the plate-shaped portion 31 and the cylindrical portion 32 more firmly.

[0030] 3, in this example, the glass 40 does not extend beyond the plate-shaped portion 31 on the side (rear end side) opposite the cylindrical portion 32 along the axis L. This makes it possible to prevent the glass 40 from protruding beyond the plate-shaped portion 31 and interfering with other components (for example, a heat exchanger to which the glass 40 is to be attached). In this example, when the maximum radial distance between the outer surface of the heater body 20 and the inner surface of the cylindrical portion 32 is D1 and the maximum radial distance between the outer surface of the cylindrical portion 32 and the outer edge 31e of the plate-like portion 31 is D2, D1>D2 holds. In this way, the diameter of the flange 30 can be reduced, and the flange 30, and therefore the ceramic heater 11, can be made smaller.

[0031] Furthermore, in this example, an extension 31f is provided on the inner surface of the plate-like portion 31, which extends toward the cylindrical portion 32 and serves as a guide to the outer surface of the heater body 20. This facilitates positioning when inserting the plate-like portion 31 into the heater body 20. In the example of Fig. 3, the inner surface side of the plate-like portion 31 is bent to form the extension portion 31f.

[0032] Fig. 4 shows a modified example of the flange of the ceramic heater according to the embodiment of the present invention. In Fig. 4, the same components as those of the ceramic heater in Fig. 3 are given the same reference numerals and the description thereof will be omitted. 4, in this example, an extension 35f on the inner surface of the plate-shaped portion 35 is a thick portion that extends perpendicularly from the main surface of the plate-shaped portion 35. The extension 35f can be formed by pressing the plate-shaped portion 35, for example. In this example, the glass 41 is interposed beyond the plate-like portion 35 on the opposite side (rear end side) of the cylindrical portion 32 along the axis L. This makes it possible to more firmly fix the flange 30 and the heater body 20.

[0033] Also, in this example, D1 < D2. In the ceramic heater 11, the plate-like portion 31 that protrudes outward from the cylindrical portion 32 is sandwiched vertically (in the axial direction) by the fixing portions on the heat exchanger side that are to be fixed, thereby being fixed to the heat exchanger. Therefore, the larger the diameter of the plate-like portion 31 that serves as a flange, in other words, the smaller D1 < D2 is, the more firmly it can be fixed to the heat exchanger to be fixed.

[0034] The ceramic heater 11 can be manufactured, for example, as follows. First, with the orientation of FIG. 3 reversed vertically and the tip 20a of the heater body 20 facing upward, using a predetermined jig, the plate-like portion 31 is inserted and disposed through the heater body 20, and the cylindrical portion 32 is disposed so as to surround the heater body 20 above the plate-like portion 31. Due to the weight of the cylindrical portion 32, the gap G1 becomes minimum. In this way, with the plate-like portion 31 and the cylindrical portion 32 combined, a ring-shaped glass solidified in the region R is disposed from above (from the cylindrical portion 32 side). Then, the whole is heated to melt the glass, and the region R is filled with the glass 40. After that, the glass 40 solidifies. Even if some glass drips from the gap between the plate-like portion 31 and the heater body 20, it solidifies appropriately. Of course, instead of using the ring-shaped glass, with the plate-like portion 31 and the cylindrical portion 32 combined, the molten glass 40 may be poured into the region R. In this way, the flange 30 is joined to the heater body 20.

[0035] The present invention is not limited to the above-described embodiments, and it goes without saying that it extends to various modifications and equivalents included in the spirit and scope of the present invention. The ceramic tube 21 may be rod-shaped without having a through hole 21h. Also, the plate-like portion may not be disk-shaped, and may be a square or polygonal plate. The cylindrical portion is not limited to a cylinder, and may be a polygonal cylinder or the like.

Explanation of Reference Numerals

[0036] 11 Ceramic heater 20 Heater body 30 Flange 31, 35 Plate-shaped part 31e, 35e Outer edge of plate 31f, 35f extension part 32 Cylindrical section 40 Encapsulating material L axis R region G1 Gap

Claims

1. A rod-shaped or cylindrical ceramic heater body; a flange provided around an axis of the heater body to form a cylindrical shape, the flange into which the heater body is inserted, the flange is a separate member, and is formed by joining, along the axis, a plate-like portion having an insertion hole for the heater body and a cylindrical portion surrounding the heater body and extending in the axial direction along an outer surface of the heater body, The plate-shaped portion protrudes radially outward beyond the cylindrical portion, a sealing material is filled in an area surrounded by the plate-like portion, the cylindrical portion, and the outer surface of the heater body, and the flange and the heater body are joined together to form a ceramic heater.

2. 2. The ceramic heater according to claim 1, wherein said plate-shaped portion and said cylindrical portion are fixed to each other by said sealing material.

3. 3. The ceramic heater according to claim 2, wherein a gap is provided between said plate-like portion and said cylindrical portion, said gap being filled with said sealing material.

4. 3. The ceramic heater according to claim 1, wherein the sealing material does not extend beyond the plate-like portion on the side opposite to the cylindrical portion along the axis.

5. 3. The ceramic heater according to claim 1, wherein the sealing material is disposed beyond the plate-like portion on a side opposite to the cylindrical portion along the axis.

6. The maximum distance in the radial direction between the outer surface of the heater body and the inner surface of the cylindrical portion is defined as D1, When the maximum radial distance between the outer surface of the cylindrical portion and the outer edge of the plate-shaped portion is D2, 3. The ceramic heater according to claim 1, wherein D1>D2.

7. The maximum distance in the radial direction between the outer surface of the heater body and the inner surface of the cylindrical portion is defined as D1, When the maximum radial distance between the outer surface of the cylindrical portion and the outer edge of the plate-shaped portion is D2, 3. The ceramic heater according to claim 1, wherein D1<D2.

8. 3. The ceramic heater according to claim 1, wherein an extension portion is provided on an inner surface of said plate-like portion, said extension portion extending toward said cylindrical portion and serving as a guide to an outer surface of said heater body.

9. 3. The ceramic heater according to claim 1, wherein the sealing material is glass.

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