JP6845706B2 - Ceramic heater - Google Patents

Description

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

Conventionally, for example, a heat exchange unit having a resin container (heat exchanger) has been used for a warm water washing toilet seat, and this heat exchange unit is used to warm the washing water contained in the heat exchanger. , A long pipe-shaped ceramic heater is arranged.
As this ceramic heater, a ceramic sheet in which heater wiring is printed is wound around a cylindrical ceramic porcelain tube and integrally fired. Further, a flange is joined to the outer periphery of the ceramic heater body by glass or the like, and the ceramic heater is fixed to the heat exchanger via the flange (see Patent Document 1).
Then, the water flowing in the gap between the inner wall of the heat exchanger and the outer circumference of the ceramic heater is heated by the ceramic heater.

Japanese Unexamined Patent Publication No. 2006-236617

By the way, if the axial center of the ceramic heater body and the axial center of the flange are misaligned (misaligned), the clearance between the inner wall of the heat exchanger and the ceramic heater becomes narrow. For this reason, the flow of water through the gap is blocked, the water temperature fluctuates, the water evaporates locally at once to generate bubbles, and if the heater and the resin heat exchanger come into contact, the heat exchanger softens. There is a risk of deformation.
Therefore, an object of the present invention is to provide a ceramic heater that suppresses misalignment between a tubular ceramic substrate and a flange joined to the outer periphery thereof.

In order to solve the above problems, the ceramic heater of the present invention is joined to the outer periphery of the ceramic base via a joining member with a cylindrical ceramic base extending in the axial direction in which a heat generating resistor is embedded inside, and is annular. Alternatively, a ceramic heater comprising an endd ring ceramic flange, at least partially embedded in the joining member, in a space between the outer peripheral surface of the ceramic substrate and the inner peripheral surface of the flange. It is characterized by having an arranged annular or endless annular metal member.

According to this ceramic heater, a metal member is arranged between the ceramic substrate and the flange so as to fill the gap between the two. Therefore, when joining the flange to the ceramic substrate, by arranging the metal member in the gap between the ceramic substrate and the flange in advance, the gap is filled and the misalignment (misalignment between the axes of the ceramic substrate and the flange) is suppressed. be able to.

In the ceramic heater of the present invention, the metal member may have a plurality of protrusions extending outward in the radial direction, and the protrusions may be in contact with the inner peripheral surface of the flange.
According to this ceramic heater, a force is applied to center the protrusions in contact with the inner peripheral surface of the flange so that the axes of the ceramic substrate and the flange are aligned (that is, the gaps are more even in the circumferential direction). , The misalignment can be further suppressed.

In the ceramic heater of the present invention, the ceramic heater has a tapered surface that is tapered inward in the radial direction from one surface of the flange toward the inner peripheral surface, and the metal member is formed on the tapered surface and the outer periphery of the ceramic substrate. It may be in contact.
According to this ceramic heater, when joining a flange to a ceramic substrate, a metal member is arranged in advance in the gap between the ceramic substrate and the flange from the tapered surface side, and when pressed against the tapered surface side, the metal member is along the tapered surface. The metal member stops moving when it moves to the tapered surface side and comes into contact with both the outer periphery of the ceramic substrate and the tapered surface. At this time, a force for centering the metal member so that the axis of the metal member is exactly aligned with the axis of the flange acts, and the misalignment between the ceramic substrate and the flange can be substantially eliminated.

In the ceramic heater of the present invention, the joining member may be interposed between the ceramic substrate, the flange, and the metal member on the opposite side of the tapered surface.
According to this ceramic heater, the joining member does not intervene on one surface side of the flange with respect to the tapered surface of the metal member, and the amount of the joining member used can be reduced.

In the ceramic heater of the present invention, the metal member may be an endd ring forming an arc of 3/4 or more around the entire circumference.
According to this ceramic heater, since the metal member has an endless ring shape, it bends in the radial direction and can be easily placed in the gap between the ceramic substrate and the flange. Further, since the metal member forms an arc of 3/4 or more of the entire circumference, the metal member is interposed in a larger portion of the gap between the ceramic substrate and the flange, and this gap can be reliably filled.

In the ceramic heater of the present invention, the coefficient of linear expansion of the metal member may be larger than the coefficient of linear expansion of the flange.
According to this ceramic heater, when the joining material to be the joining member is heated, the metal member expands to further fill the gap between the ceramic substrate and the flange. In particular, the metal member expands to fill the inner circumference of the flange. When it comes into contact with the surface, even if the ceramic substrate and the flange are misaligned, this can be corrected and a centering force can be applied.

In the ceramic heater of the present invention, the joining member may be made of glass, epoxy resin, or brazing material.
When these materials are heated, they easily flow into the gap between the ceramic substrate and the flange, and can be solidified in a state where the metal member is embedded.

In the ceramic heater of the present invention, the flange may be made of alumina.
This material has a low cost and can surely make the coefficient of linear expansion of the flange smaller than the coefficient of linear expansion of the metal member.

In the ceramic heater of the present invention, the metal member may be made of any of copper, nickel or nickel alloy, titanium or titanium alloy, or stainless steel.
These materials are excellent in corrosion resistance and also excellent in wettability with molten glass when glass is used as a joining member.

In the ceramic heater of the present invention, among the joining members, the point on the tip facing surface located on the most tip side in the axial direction passes through the first point approaching the rearmost end side in the axial direction. A second virtual line A perpendicular to the axis, and a point on the rear end facing surface located on the rearmost end side in the axis direction of the joining member, which is closest to the tip end side in the axis direction. The thickness D1 of the joining member represented by the shortest distance from the virtual line B perpendicular to the axis passing through the point may be ½ or more of the maximum thickness D2 of the flange.
According to this ceramic heater, among the portions where the joining member supports both sides of the flange in the axial direction, the portion having a thickness of D1 which is thin and weak in strength is maintained at 1/2 or more of D2, so that the ceramic substrate is used. Can be reliably joined to the flange.

According to the present invention, it is possible to suppress misalignment between the cylindrical ceramic substrate in the ceramic heater and the flange joined to the outer periphery thereof.

It is a front view which shows the ceramic heater which concerns on 1st Embodiment of this invention. It is a developed view which shows the ceramic sheet of a ceramic heater. It is sectional drawing which follows the axial direction of FIG. It is sectional drawing which follows the AA line of FIG. It is a perspective view which shows the appearance of a metal member. It is a partial cross-sectional view which shows the method of joining a flange to a ceramic substrate via a metal member. It is a partial cross-sectional view along the axial direction of the ceramic heater which concerns on 2nd Embodiment of this invention. FIG. 5 is a partial cross-sectional view showing a method of joining a flange to a ceramic substrate via a metal member in the ceramic heater according to the second embodiment of the present invention. It is a partial cross-sectional view which shows the deformation example of a metal member.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing the ceramic heater 11 according to the first embodiment of the present invention, FIG. 2 is a developed view showing a ceramic sheet 19 of the ceramic heater 11, and FIG. 3 is a cross-sectional view taken along the axis L direction of FIG. FIG. 4 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 5 is a perspective view showing the appearance of the metal member 50.
The ceramic heater 11 according to the first embodiment of the present invention can be used for warming the washing water, for example, in the heat exchanger of the heat exchange unit of the warm water washing toilet seat.

As shown in FIG. 1, the ceramic heater 11 is joined to the outer periphery of the ceramic base 13 via a joining member 20 with a tubular ceramic base 13 in which a heat generating resistor 40 is embedded, and is annular or endless annular. The ceramic flange 30 and the annular or endless annular metal member 50 (see FIG. 3) are provided.
The ceramic substrate 13 includes a cylindrical ceramic support 17 and a ceramic sheet 19 wound around the outer periphery of the support 17, and the support 17 has a through hole 17h in the L direction of the axis. .. Then, in the heat exchanger, the water flowing inside the through hole 17h is heated by the ceramic heater 11, and 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 support 17 and the ceramic sheet 19 can be formed from, for example, alumina. The ceramic sheet 19 does not completely cover the outer periphery of the support 17, and the wound portion 19a of the ceramic sheet 19 is formed with slits 13s extending along the axis L direction of the support 17.

On the other hand, as shown in FIG. 2, on the ceramic sheet 19, a heat generating resistor 40 formed of a meandering pattern-shaped heater wiring is formed by printing or the like. The heater wiring of the heat generation resistor 40 has a form in which both ends of a plurality of wiring portions 40a extending along the axis L direction extend in the width direction and are connected to the end portions of the adjacent wiring portions 40a. The wiring portions 40a at both ends of the ceramic sheet 19 in the width direction are integrally connected to the pad-shaped internal terminal 42 at one end in the axis L direction.
The internal terminal 42 is electrically connected to the external terminal 43 formed on the outer peripheral surface (back surface of FIG. 2) of the ceramic sheet 19 via a via conductor (not shown) or the like.
The heat generation resistor 40 and the internal terminal 42 can be formed of, for example, tungsten as a main component.

Next, the metal member 50 will be described with reference to FIGS. 3 to 5.
As shown in FIG. 5, the metal member 50 has a C-shaped ended ring shape when viewed from above, and a part in the circumferential direction forms an opening 50c. Further, the metal member 50 has four protrusions 50p extending radially outward from its outer peripheral surface at equal intervals in the circumferential direction.
In the present embodiment, the metal member 50 is formed by bending a stainless steel (SUS304) plate in an annular shape, and one end in the axial direction (lower end in FIG. 5) is cut out in a U shape to provide a cutout portion 50d. , A piece of the cutout portion 50d is cut up radially outward to form a protrusion 50p.
Then, as shown in FIG. 3, the metal member 50 is embedded in the joining member 20 while its own protrusion 50p is in contact with the inner peripheral surface 30d of the flange 30. The diameter of the flange 30 is gradually reduced from the inner peripheral surface 30d toward one end in the axis L direction (lower end in FIG. 3), and from the inner peripheral surface 30d to the other end in the axis L direction (upper end in FIG. 3). The tapered portion 30a is formed by expanding the diameter toward the taper. Then, the joining material 20x (FIG. 6) to be the joining member 20 can be easily inserted from the tapered portion 30a side where the gap between the ceramic substrate 13 and the flange 30 is widened.

Here, as shown in FIG. 4, the metal member 50 is arranged between the ceramic base 13 and the flange 30 so as to fill a gap between them. Therefore, when joining the flange 30 to the ceramic substrate 13, as shown in FIG. 6, by arranging the metal member 50 in the gap between the ceramic substrate 13 and the flange 30 in advance, the gap is filled and the misalignment (ceramic substrate) is filled. It is possible to suppress the deviation between the axes of the 13 and the flange 30).
Then, after arranging the metal member 50, the solid bonding material 20x to be the bonding member 20 is inserted into the gap between the ceramic substrate 13 and the flange 30 (covering the metal member 50), and the whole is heated to heat the bonding material 20x. Is melted and solidified. As a result, the metal member 50 is embedded in the joining member 20, and the flange 30 is joined to the outer periphery of the ceramic substrate 13.

In particular, in the present embodiment, since the metal member 50 is provided with a plurality of protrusions 50p and the protrusions 50p are brought into contact with the inner peripheral surface 30d of the flange 30, the axes of the ceramic substrate 13 and the flange 30 are aligned (that is,). A centering force acts so that the gap G (see FIG. 6) becomes more even in the circumferential direction), and the misalignment can be further suppressed.

As shown in FIG. 5, the metal member 50 is preferably an endd ring having a circumference of 50 L forming an arc of 3/4 or more of the entire circumference. If the ring is endless, the metal member 50 bends in the radial direction, so that it can be easily arranged in the gap between the ceramic substrate 13 and the flange 30. Further, since the metal member 50 forms an arc of 3/4 or more of the entire circumference, the metal member 50 is interposed in a larger portion of the gap between the ceramic substrate 13 and the flange 30, and the gap can be reliably filled. it can.
Further, it is preferable that the coefficient of linear expansion of the metal member 50 is larger than the coefficient of linear expansion of the flange 30. As a result, when the joining material 20x to be the joining member 20 is heated, the metal member 50 expands and the gap between the ceramic substrate 13 and the flange 30 can be further filled. In particular, the metal member 50 expands and the flange 30 In the case of contact with the inner peripheral surface 30d of the above, even if the ceramic substrate 13 and the flange 30 are misaligned, it is possible to correct the misalignment and apply a centering force.

From this point of view, the metal member 50 may be formed of copper, nickel or nickel alloy, titanium or titanium alloy, or stainless steel. Further, these materials are excellent in corrosion resistance and also excellent in wettability with molten glass when glass is used as the joining member 20.
Further, the flange 30 may be formed of alumina.
Further, the joining member 20 may be made of glass, epoxy resin, or brazing material.
Further, as shown in FIG. 3, among the joining members 20, the first point P1 which is a point on the tip facing surface located on the most tip side in the axis L direction and approaches the rearmost end side in the axis L direction. A virtual line A perpendicular to the axis L and a point on the rear end facing surface of the joining member 20 located on the rearmost end side in the axis L direction, and on the most tip side in the axis L direction. When the thickness D1 represented by the shortest distance to the virtual line B perpendicular to the axis L passing through the second approaching point P2 is ½ or more of the maximum thickness D2 of the flange 30, the flange on the ceramic substrate 13 30 can be reliably joined.
This means that D1 represents a portion where the joining member 20 supports both sides of the flange 30 in the axial direction and is thin, and the joining strength can be ensured unless this D1 is 1/2 or more of D2. This is because it can be difficult.
Further, D1 when the first point P1 is referred to both sides of the flange 30 is obtained, and the smallest value thereof is adopted as D1. In the example of FIG. 3, the first point is P2 when viewed from the side facing the other surface (upper surface of FIG. 3) of the flange 30, but D1 obtained with reference to this is one surface of the flange 30. Since it is equal to the above-mentioned D1 based on (the lower surface of FIG. 3), any value may be adopted.

The ceramic heater 11 can be manufactured, for example, as follows.
First, a member to be a support 17 is extruded from a slurry of ceramic powder such as alumina and calcined. Further, a green sheet to be a ceramic sheet 19 is formed from the same slurry as described above, and a conductive paste to be a heat generating resistor 40 and an internal terminal 42 as shown in FIG. 2 is printed on the surface thereof and dried. Then, another green sheet is laminated and pressed on the printed surface of the green sheet, and the heat generating resistor 40 and the internal terminal 42 are embedded between the two green sheets. Further, a conductive paste serving as an external terminal 43 is printed on one side of the laminate of both green sheets and dried.
Then, a ceramic paste is applied to the opposite surfaces of the laminated bodies of both green sheets, wrapped around the support 17 and adhered, and the whole is fired.
Further, a ceramic powder such as alumina is pressure-molded with a mold and fired to obtain a flange 30.

After the ceramic substrate 13 and the flange 30 manufactured in this manner are arranged via the metal member 50 as shown in FIG. 6, the solid bonding material 20x (glass) to be the bonding member 20 is placed on the ceramic substrate 13 and the flange 30. The flange 30 is joined to the outer periphery of the ceramic substrate 13 by arranging it in the gap between the ceramic substrate 13 and heating it above the melting temperature of the glass.

Next, the ceramic heater according to the second embodiment of the present invention will be described with reference to FIGS. 7 and 8. Since the ceramic heater according to the second embodiment is the same as the ceramic heater according to the first embodiment except that the configurations of the flange 32 and the metal member 52 are different, the description of the same configuration portion will be omitted. .. Further, since the overall configuration of the ceramic heater according to the second embodiment is substantially the same as that of FIG. 1, FIGS. 7 and 8 are simplified as partial cross-sectional views of the ceramic heater.

As shown in FIG. 7, a tapered tapered surface 32b is formed that narrows inward in the radial direction from one surface of the flange 32 (lower surface of FIG. 7) toward the inner peripheral surface. Further, a tapered tapered surface 32a is formed that narrows inward in the radial direction from the other surface of the flange 32 (upper surface in FIG. 7) toward the inner peripheral surface.
On the other hand, the metal member 52 is a ring having a circular cross section that connects endlessly.
Then, the metal member 52 is in contact with the tapered surface 32b and the outer periphery of the ceramic substrate 13. Further, the joining member 20 is interposed between the ceramic substrate 13, the flange 2, and the metal member 52 on the opposite side of the tapered surface 32b. That is, the joining member 20 does not intervene on the lower surface of the metal member 52, and a part of the metal member 52 is embedded in the joining member 20.
When the metal member 52 has a C-shaped ended ring shape, the melt of the joining member 20 flows from the notch portion of the metal member 52 to the lower part of the metal member 52, and the lower part of the metal member 52 is also a joining member. It may be buried in 20.

Here, as shown in FIG. 8, when joining the flange 32 to the ceramic base 13, a metal member 52 is arranged in advance in the gap between the ceramic base 13 and the flange 32 from the tapered surface 32b side, and a jig 100 or the like is used. When a predetermined pressing force F is applied to the tapered surface 32b side (upper side), the metal member 52 moves upward along the tapered surface 32b, and when the outer periphery of the ceramic substrate 13 and the tapered surface 32b come into contact with each other, the metal member 52 moves upward. The movement of 52 stops. At this time, a force for centering the metal member 52 so that the axis of the metal member 52 is exactly aligned with the axis of the flange 32 acts, and the misalignment between the ceramic substrate 13 and the flange 32 can be substantially eliminated.
Then, after arranging the metal member 52, the solid bonding material 20x to be the bonding member 20 is inserted into the gap between the ceramic substrate 13 and the flange 32 (from above the metal member 52), and the whole is heated to heat the bonding material 20x. Is melted and solidified. As a result, the upper portion of the metal member 52 is embedded in the joining member 20, and the flange 32 is joined to the outer periphery of the ceramic substrate 13.
As described above, in the second embodiment, the action of the tapered surface 32b exerts a centering effect in which the gap G (see FIG. 8) between the ceramic substrate 13 and the flange 32 becomes substantially uniform in the circumferential direction, thereby causing misalignment. Almost resolved.

It goes without saying that the present invention is not limited to the above embodiments and extends to various modifications and equivalents included in the ideas and scope of the present invention.
The shape of the metal member is not limited. For example, as shown in FIG. 9, a metal plate having a C-shaped cross section is formed in an annular shape to form a metal member 54 that bends in the radial direction, and a gap between the ceramic substrate 13 and the flange 34. You may make it adhere to.
The shape of the flange is also not limited.

11 Ceramic heater 13 Ceramic substrate 20 Joining member 30, 32, 34 Flange 30d Inner peripheral surface of flange 32b Tapered surface 40 Heat generating resistor 50, 52, 54 Metal member 50p Protrusion D1 Thickness of joining member D2 Maximum thickness of flange L Axis P1 First point P2 Second point A, B Virtual line

Claims (10)

A cylindrical ceramic substrate extending in the axial direction with a heat-generating resistor embedded inside,
A ceramic heater that is joined to the outer periphery of the ceramic substrate via a joining member and includes an annular or endless annular ceramic flange.
A ceramic characterized in that at least a part thereof is embedded in the joining member and has an annular or endless annular metal member arranged in a space between an outer peripheral surface of the ceramic substrate and an inner peripheral surface of the flange. heater. The ceramic heater according to claim 1, wherein the metal member has a plurality of protrusions extending outward in the radial direction, and the protrusions are in contact with the inner peripheral surface of the flange. Claim 1 has a tapered tapered surface that narrows inward in the radial direction from one surface of the flange toward the inner peripheral surface, and the metal member is in contact with the tapered surface and the outer periphery of the ceramic substrate. The ceramic heater described in. The ceramic heater according to claim 3, wherein the joining member is interposed between the ceramic substrate, the flange, and the metal member on the opposite side of the tapered surface. The ceramic heater according to any one of claims 1 to 4, wherein the metal member is an endd ring forming an arc of 3/4 or more of the entire circumference. The ceramic heater according to any one of claims 1 to 5, wherein the coefficient of linear expansion of the metal member is larger than the coefficient of linear expansion of the flange. The ceramic heater according to any one of claims 1 to 6, wherein the joining member is made of glass, epoxy resin, or brazing material. The ceramic heater according to any one of claims 1 to 7, wherein the flange is made of alumina. The ceramic heater according to any one of claims 1 to 8, wherein the metal member is made of copper, nickel or nickel alloy, titanium or titanium alloy, or stainless steel. A virtual joint member perpendicular to the axis that passes through a point on the tip-facing surface located on the most tip side in the axis direction and that is closest to the rearmost end side in the axis direction. The line A and the point on the rear end facing surface located on the rearmost end side in the axial direction of the joining member, which passes through the second point closest to the tip end side in the axial direction. The ceramic according to any one of claims 1 to 9, wherein the thickness D1 of the joining member represented by the shortest distance from the virtual line B perpendicular to the axis is ½ or more of the maximum thickness D2 of the flange. heater.

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