KR20180125993A - Ceramic Heaters - Google Patents

Abstract

The ceramic heater of the present disclosure includes a ceramic sheet wound around the periphery of a support and having heater wiring. The heater wiring includes a wiring portion extending along the axial direction of the support and a connecting portion connecting the adjacent wiring portions. The wiring portion includes a pair of outer wiring portions disposed on opposite sides of the ceramic sheet with the junction portion therebetween, and an inner wiring portion disposed between the pair of outer wiring portions in the ceramic sheet. The cross-sectional area of the outer wiring portion is larger than the cross-sectional area of the inner wiring portion.

Description

Ceramic Heaters

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic heater for use in, for example, a hot water washing toilet seat, a fan heater, an electric water heater, a 24-hour bath, a soldering iron, The present invention relates to a ceramic heater having a structure in which a ceramic sheet is wound.

(Cross reference of related application)

The present international application is based on Japanese Patent Application No. 2016-051823 filed on March 16, 2016, Japanese Patent Application No. 2016-051823, filed on March 16, 2016, and Japanese Patent Application No. 2016 -051824, the entire contents of Japanese Patent Application No. 2016-051823, and the entire contents of Japanese Patent Application No. 2016-051824, all of which are incorporated herein by reference.

Generally, a heat exchange unit having a container made of resin (heat exchanger) is used for the hot water washing flat. The heat exchanging unit is equipped with a cylindrical ceramic heater for warming the washing water contained in the heat exchanger.

As a ceramic heater of this kind, it is known that a ceramic sheet printed with heater wiring is wound around a support made of a cylindrical ceramic, and the ceramic sheet is integrally fired (see, for example, Patent Document 1).

Patent Document 1: Japanese Patent No. 3038039

However, since the ceramic heater of the hot water washing unit is always in the water, it hardly energizes and is heated in the dry state. On the other hand, when the water breaks or the piping breaks down, there is a possibility of energization and heating in a dry state. However, since the cross-sectional area (for example, line width, thickness) of the common heater wiring is uniform, when heated in the dry state, the heater wiring is locally heated at the junction of the ceramic sheets, There is a possibility that the glass component present in the ceramic sheet of the glass sheet is melted. In this case, since electrons are easily moved, there is a possibility that partial discharge occurs between a pair of heater wirings located on opposite sides of the junction portion, leading to insulation breakdown. Further, since the ceramic component present in the ceramic sheet is also melted by the spark generated at the partial discharge, there is a possibility that the ceramic heater is broken.

In one aspect of the present disclosure, it is desirable to provide a ceramic heater capable of improving reliability by suppressing dielectric breakdown in heater wiring.

One aspect of the present disclosure is a ceramic heater comprising a support made of ceramic and a ceramic sheet wound around the periphery of the support and having a heater wiring, wherein the heater wiring has a plurality of wiring portions and connection portions, A pair of outer wiring portions and an inner wiring portion, and the cross-sectional area of the outer wiring portion is larger than the cross-sectional area of the inner wiring portion.

The plurality of wiring portions are configured to extend along the axial direction of the support body. The connection portion is configured to connect adjacent wiring portions. The pair of outer wiring portions are disposed on the opposite sides with respect to each other with a bonding portion of the ceramic sheet (a portion contacting each other when the ceramic sheet is wound around the outer periphery of the support). The inner wiring portion is disposed between the pair of outer wiring portions in the ceramic sheet.

In this ceramic heater, the cross-sectional area of a pair of outer wiring portions positioned on the opposite sides with the junction of the ceramic sheets sandwiched therebetween is made larger than the cross-sectional area of the inner wiring portion disposed between the pair of outer wiring portions in the ceramic sheet, The electrical resistance of the outer wiring portion becomes smaller than the electrical resistance of the inner wiring portion. Therefore, it becomes possible to suppress the local heat generation of the heater wiring at the junction where the outer wiring portion is located. As a result, melting of the glass component present in the ceramic sheet adjacent to the outer wiring portion is suppressed, so that breakdown of insulation between the pair of outer wiring portions can be suppressed, and breakage of the ceramic heater can be suppressed . Therefore, the reliability of the ceramic heater can be improved.

The configuration in which the cross-sectional area of the outer wiring portion is larger than the cross-sectional area of the inner wiring portion is, for example, a configuration in which the line width of the outer wiring portion is larger than the line width of the inner wiring portion. In other words, by making the line width of the pair of outer wiring parts larger than the line width of the inner wiring part, the electric resistance of the outer wiring part becomes smaller than the electric resistance of the inner wiring part, so that the local heat generation of the heater wiring can be suppressed.

The line width of the outer wiring portion may be set to be larger than or equal to 1.07 times the line width of the inner wiring portion and less than 2.4 times. Since the line width of the outer wiring portion is set to be larger than 1.07 times the line width of the inner wiring portion, it is possible to suppress the local heat generation of the outer wiring portion or to prevent the insulation breakdown between the pair of outer wiring portions located on the opposite sides with the junction portion therebetween Can be suppressed. On the other hand, since the line width of the outer wiring portion is set to be less than 2.4 times the line width of the inner wiring portion, the temperature of the outer wiring portion can be suppressed from becoming locally low, and the deterioration of the cracking uniformity can be suppressed.

In a configuration in which the cross-sectional area of the outer wiring portion is larger than the cross-sectional area of the inner wiring portion, for example, the thickness of the outer wiring portion is thicker than the thickness of the inner wiring portion. That is, by making the thickness of the pair of outer wiring parts larger than the thickness of the inner wiring part, the electrical resistance of the outer wiring part becomes smaller than the electrical resistance of the inner wiring part.

The thickness of the outer wiring portion may be set to be larger than 1.25 times the thickness of the inner wiring portion and less than 2.4 times the thickness of the inner wiring portion. Since the thickness of the outer wiring portion is set to be larger than 1.25 times the thickness of the inner wiring portion, it is possible to suppress the local heat generation of the outer wiring portion or to prevent the insulation breakdown between the pair of outer wiring portions located on the opposite sides with the junction portion therebetween Can be suppressed. On the other hand, by setting the thickness of the outer wiring portion to be less than 2.4 times the thickness of the inner wiring portion, the temperature of the outer wiring portion can be suppressed from becoming locally low, and the degradation of cracking property can be suppressed.

Another aspect of the present disclosure is a ceramic heater comprising a ceramic support and a ceramic sheet wound around the periphery of the support and having a heater wiring, wherein the heater wiring includes a plurality of wiring portions and connection portions, A pair of outer wiring portions and an inner wiring portion, and the cross-sectional area of the central portion of the outer wiring portion is larger than the cross-sectional area of the inner wiring portion.

The plurality of wiring portions are configured to extend along the axial direction of the support body. The connection portion is configured to connect adjacent wiring portions. The pair of outer wiring portions are arranged on the opposite sides with the joint portion of the ceramic sheet interposed therebetween. The inner wiring portion is disposed between the pair of outer wiring portions in the ceramic sheet.

In this ceramic heater, the cross-sectional area of a center portion of a pair of outer wiring portions located on opposite sides of a joint portion of the ceramic sheet is set larger than the cross-sectional area of the inner wiring portion disposed between the pair of outer wiring portions in the ceramic sheet The electric resistance of the central portion of the outer wiring portion becomes smaller than the electric resistance of the inner wiring portion. Therefore, local heat generation of the heater wiring can be suppressed at the junction where the outer wiring portion is located. As a result, since the melting of the glass component present in the ceramic sheet near the central portion of the outer wiring portion is suppressed, the insulation breakdown between the pair of outer wiring portions can be suppressed and the breakage of the ceramic heater can be suppressed have. Therefore, the reliability of the ceramic heater can be improved.

In the configuration in which the cross-sectional area of the central portion of the outer wiring portion is larger than the cross-sectional area of the inner wiring portion, for example, the wiring width of the central portion of the outer wiring portion is larger than the line width of the inner wiring portion. That is, by making the line width of the central portion of the pair of outer wiring portions larger than the line width of the inner wiring portion, the electric resistance at the central portion of the outer wiring portion becomes smaller than the electric resistance of the inner wiring portion, do.

The line width of the central portion may be set to 1.07 times or more and 2.0 times or less of the line width of the inner wiring portion. The line width of the central portion is set to be larger than 1.07 times the line width of the inner wiring portion so that the outer wiring portion is prevented from locally generating heat and insulation breakdown occurs between the pair of outer wiring portions located on opposite sides with the junction portion therebetween . On the other hand, since the line width of the central portion is set to be not more than 2.0 times the line width of the inner wiring portion, the temperature of the outer wiring portion can be suppressed from becoming locally low, and the degradation of cracking property can be suppressed.

The ceramic heater includes a ceramic support and a ceramic sheet wound around the periphery of the support. Examples of the ceramic forming the support and the ceramic sheet include alumina, aluminum nitride, silicon nitride, boron nitride, zirconia, titania, and water light. In particular, the support and the ceramic sheet may be provided with alumina. By doing so, a ceramic heater excellent in heat resistance, chemical resistance and strength can be produced at low cost. Further, the ceramic sheet has a heating element (heater wiring) formed using, for example, tungsten, molybdenum, tantalum or the like. Further, the heater wiring may include at least one kind of tungsten and molybdenum as a main component. In this case, since the heater wiring can be surely brought into close contact with the ceramic sheet, the reliability of the ceramic heater is further improved.

1 is a front view of a ceramic heater according to a first embodiment;
2 is a plan view showing a ceramic heater according to the first embodiment;
3 is a cross-sectional view taken along line III-III in Fig.
Fig. 4 is an explanatory view showing the development of the ceramic sheet in the first embodiment. Fig.
FIGS. 5A, 5B, 5C, and 5D are explanatory diagrams showing a method of manufacturing the ceramic heater in the first embodiment; FIGS.
6 is an explanatory view showing the development of the ceramic sheet according to the second embodiment.
7 is a front view of the ceramic heater according to the third embodiment.
8 is a plan view showing the ceramic heater according to the third embodiment.
9 is a sectional view taken along line IX-IX of Fig.
Fig. 10 is an explanatory view showing the development of the ceramic sheet in the third embodiment. Fig.
11A, 11B, 11C, and 11D are explanatory diagrams showing a method of manufacturing the ceramic heater according to the third embodiment.
12 is a cross-sectional view of a main part showing a support and a ceramic sheet in the fourth embodiment;
13 is an explanatory view showing the development of the ceramic sheet according to the fourth embodiment.

[First Embodiment]

Hereinafter, a ceramic heater according to a first embodiment embodying the present disclosure and a manufacturing method thereof will be described with reference to the drawings.

The ceramic heater 11 of the present embodiment is used for warming the washing water in, for example, a heat exchanger of a heat exchange unit of a hot water washing seat.

As shown in Figs. 1 and 2, the ceramic heater 11 includes a cylindrical ceramic heater body 13 and a metal annular flange 15 fitted outside the heater body 13 . The flange 15 is an annular member formed by bending a metal plate such as stainless steel, for example, and has a concave (cup-shaped) central portion.

2, a space surrounded by the outer peripheral surface 14 of the heater body 13 and the inner surface of the flange 15 out of the concave portions of the flange 15 is provided in the glass storage portion 35, . The glass storage portion 35 is filled with a glass 33 and the heater body 13 and the flange 15 are welded and fixed via the glass 33. [ In Fig. 2, the portion of the glass 33 is hatched.

1 to 3, the heater body 13 is constituted by a ceramic support 17 made of a cylindrical shape and a ceramic sheet 19 wound around the periphery of the support 17. In the present embodiment, the support member 17 and the ceramic sheet 19 are made of ceramics such as alumina (Al ₂ O ₃ ). The thermal expansion coefficient of alumina is in the range of 50 x 10 ^-7 / K to 90 x 10 ^-7 / K, and in this embodiment, it is set to 70 x 10 ^-7 / K (30 to 380 캜). In this embodiment, the outside diameter of the support body 17 is set to 12 mm, the inside diameter to 8 mm, and the length to 65 mm, and the thickness of the ceramic sheet 19 is set to 0.5 mm and the length to 60 mm. Further, the ceramic sheet 19 does not completely cover the outer periphery of the support 17. Therefore, the joining portion 20 of the ceramic sheet 19 is formed with a slit 21 extending along the axial direction of the support 17 and exposing the outer circumferential surface of the support 17. The slit 21 of this embodiment has a width of 1 mm and a depth of 0.5 mm.

As shown in Fig. 3 and Fig. 4, a heater wire 41 and a pair of internal terminals 42 are formed in the ceramic sheet 19 in the form of a meandering pattern. In the present embodiment, the heater wiring 41 and the pair of internal terminals 42 include tungsten (W) as a main component. Each of the internal terminals 42 is electrically connected to an external terminal 43 (see FIG. 1) formed on the outer peripheral surface of the ceramic sheet 19 via a not-shown via conductor or the like.

The heater wiring 41 is provided with a plurality of wiring portions 44 extending along the axial direction of the support 17 and a connecting portion 45 connecting the adjacent wiring portions 44 with each other. The plurality of wiring portions 44 includes a pair of outer wiring portions 46 and a plurality of inner wiring portions 47. The pair of outer wiring portions 46 are disposed on the opposite sides of the ceramic sheet 19 with the joint portion 20 (see Fig. 3) interposed therebetween. 4) is connected to the inner terminal 42 and the second end (lower end in Fig. 4) of the outer wiring portion 46 is connected to the inner terminal 42 via the connection portion 45. The first end And is connected to the wiring portion 47. Each of the internal terminals 42 is disposed between the pair of outer wiring portions 46 when the ceramic sheet 19 is viewed in the thickness direction.

As shown in Figs. 3 and 4, each inner wiring portion 47 is disposed between a pair of outer wiring portions 46 in the ceramic sheet 19. As shown in Fig. The first end (upper end in FIG. 4) of the inner wiring portion 47 is connected to the first end of the adjacent inner wiring portion 47 via the connecting portion 45. The second end (lower end in Fig. 4) of the inner wiring portion 47 is connected to the second end of the adjacent inner wiring portion 47 or the second end of the adjacent outer wiring portion 46 via the connecting portion 45 Respectively.

In addition, the line width W1 of the outer wiring portion 46 of the present embodiment is set to 0.66 mm and the thickness thereof is set to 15 mu m. The line width W2 of the inner wiring portion 47 of the present embodiment is set to 0.60 mm and the thickness to 15 mu m. Similarly, the line width W3 of the connecting portion 45 of this embodiment is set to 0.60 mm and the thickness thereof is set to 15 mu m. That is, the line width W1 of the outer wiring portion 46 is thicker than the line width W2 of the inner wiring portion 47 and the line width W3 of the connection portion 45. More specifically, the line width W1 of the outer wiring portion 46 is set to 1.1 times the line width W2 of the inner wiring portion 47 and the line width W3 of the connection portion 45. [ The line width W2 of the inner wiring portion 47 is equal to the line width W3 of the connection portion 45. [ The cross sectional area of the outer wiring portion 46 is larger than the cross sectional area of the inner wiring portion 47 and the cross sectional area of the connection portion 45. Therefore, the thickness of the outer wiring portion 46 is equal to the thickness of the inner wiring portion 47 and the thickness of the connection portion 45, (45).

Next, a method of manufacturing the ceramic heater 11 of the present embodiment will be described.

First, a clay-shaped slurry containing alumina as a main component is put into a conventionally known extruder (not shown) to form a tubular member. Then, after the molded tubular member is dried, the support 17 (see Fig. 5A) is obtained by performing the temporary firing by heating at a predetermined temperature (for example, about 1000 캜).

Further, the first and second ceramic green sheets 51 and 52 to be the ceramic sheet 19 are formed by using a ceramic material containing alumina powder as a main component. As a method of forming the ceramic green sheet, a well-known forming method such as a doctor blade method can be used. Then, a conductive paste (tungsten paste in this embodiment) is printed on the surface of the first ceramic green sheet 51 by using a conventionally known paste printing apparatus (not shown). As a result, on the surface of the first ceramic green sheet 51, a heater wiring 41 and a non-fired electrode 53 serving as an internal terminal 42 are formed (see Fig. 5B). The line width of the unfired electrode 53 is adjusted to be, for example, the sum of the line width of the heater wiring 41 plus the shrinkage at the time of firing.

After the conductive paste is dried, the second ceramic green sheet 52 is laminated on the printed surface of the first ceramic green sheet 51 (the surface on which the unfired electrode 53 is formed), and pressure is applied in the sheet stacking direction . As a result, the first and second ceramic green sheets 51 and 52 are integrated to form a green sheet laminate 54 (see Fig. 5C). Further, a conductive paste is printed on the surface of the second ceramic green sheet 52 by using a paste printing apparatus. As a result, on the surface of the second ceramic green sheet 52, the untreated electrode 55 to be the external terminal 43 is formed.

Then, a ceramic paste (alumina paste) is applied to one side of the green sheet laminate 54, and the green sheet laminate 54 is wound around the outer circumferential surface of the support 17 and adhered thereto (see FIG. 5D). At this time, the size of the green sheet laminate 54 is adjusted so that the ends of the green sheet laminate 54 do not overlap each other. Then, the green sheet laminate 54 (the first and second ceramic green sheets 51 and 52 and the unfired electrodes 53 and 55) is subjected to a drying process or a degreasing process according to a well- (For example, about 1400 DEG C to 1600 DEG C) at which alumina and tungsten can be sintered. As a result, the alumina in the first and second ceramic green sheets 51 and 52 and the tungsten in the conductive paste are simultaneously sintered so that the green sheet laminate 54 becomes the ceramic sheet 19, The heater wire 41 and the internal terminal 42 are formed and the untreated electrode 55 becomes the external terminal 43. [ Thereafter, the external terminal 43 is plated with nickel to form the heater body 13. [

Then, a plate material made of stainless steel is press-formed by using a metal mold to form a cup-shaped flange 15. Then, the flange 15 is fitted outside at a predetermined mounting position of the heater main body 13. Thereafter, the heater body 13 and the flange 15 are welded and fixed via the glass 33 to complete the ceramic heater 11.

<Experimental Example>

Hereinafter, an experimental example for evaluating the performance of the ceramic heater 11 of the present embodiment will be described.

First, a sample for measurement was prepared as follows. The ratio of the line width of the outer wiring portion to the line width of the inner wiring portion is 1.0, in other words, the ceramic heater has the line width of the outer wiring portion of 0.60 mm, the line width of the inner wiring portion of 0.60 mm, A ceramic heater having a line width equal to the line width of the inner wiring portion was prepared, and this was designated Sample 1A. A ceramic heater having a line width of 0.64 mm for the outer wiring portion, a line width of 0.60 mm for the inner wiring portion, and a ratio of 1.07 was prepared and used as Sample 1B. A ceramic heater having a line width of 0.60 mm for the outer wiring portion, 0.55 mm for the line width of the inner wiring portion, and 1.09 for the ratio was prepared and used as Sample 1C. A ceramic heater such as the ceramic heater 11 of the present embodiment in which the line width of the outer wiring portion is 0.66 mm, the line width of the inner wiring portion is 0.60 mm, and the ratio is 1.1 is prepared, Respectively. A ceramic heater having a line width of 0.69 mm for the outer wiring portion, a line width of 0.60 mm for the inner wiring portion, and a ratio of 1.15 was prepared and used as Sample 1E. A ceramic heater having a line width of 1.20 mm of the outer wiring portion, a line width of 0.60 mm of the inner wiring portion, and a ratio of 2.0 was prepared and used as a sample 1F. A ceramic heater having a line width of 1.44 mm for the outer wiring portion, a line width of 0.60 mm for the inner wiring portion, and a ratio of 2.4 was prepared and used as a sample 1G. Five samples were prepared for each of the samples 1A to 1G.

Then, a nichrome wire was soldered to a pair of internal terminals (heater wires) included in the ceramic sheets of the respective measurement samples (samples 1A to 1G), and each measurement sample was dried, Respectively. Then, a voltage (alternating current of 240 V) was applied between the pair of internal terminals for 6 minutes, and the surface temperature of the ceramic sheet was measured with a thermocouple. It was observed whether or not local heat generation in the outer wiring portion and insulation breakdown between the pair of outer wiring portions occurred, and in the case of insulation breakage, the time of occurrence thereof was measured and recorded. Table 1 shows the above results.

Sample Line width Test result The outer wiring portion (W1) The inner wiring portion (W2) The ratio (W1 / W2) Local fever Dielectric breakdown 1A 0.60mm 0.60mm 1.0 5/5 5/5 1B 0.64mm 0.60mm 1.07 5/5 2/5 1C 0.60mm 0.55mm 1.09 0/5 0/5 1D 0.66mm 0.60mm 1.1 0/5 0/5 1E 0.69mm 0.60mm 1.15 0/5 0/5 1F 1.20mm 0.60mm 2.0 0/5 0/5 1G 1.44mm 0.60mm 2.4 0/5 0/5

As a result, it was confirmed that, in sample 1A, local exothermic heat occurred in all five samples, and sparks occurred after 1 minute and 50 seconds to cause dielectric breakdown. In Sample 1B, it was confirmed that local exothermic heat was generated in all five samples and insulation breakdown occurred in two of the five samples. On the other hand, in samples 1C to 1G, all five samples were observed for 6 minutes, but local heat generation or insulation breakdown was not observed. However, in the sample 1G, it was confirmed that the bonding portion of the ceramic sheet becomes low temperature and the cracking property is lowered.

As described above, when the line widths of the pair of outer wiring portions located on opposite sides with the junction portion therebetween are set to 1.09 times or more and 2.0 times or less of the line widths of the inner wiring portions disposed between the pair of outer wiring portions, And insulation breakdown is less likely to occur, and cracking resistance is less likely to be lowered.

Therefore, according to the present embodiment, the following effects can be obtained.

(1) In the ceramic heater 11 of the present embodiment, the line width W1 of the outer wiring portion 46 is made larger than the line width W2 of the inner wiring portion 47, Becomes smaller than the electric resistance of the inner wiring portion 47. Therefore, it is possible to suppress the local heat generation of the heater wiring 41 in the junction portion 20 where the outer wiring portion 46 is located. As a result, melting of the glass component present in the ceramic sheet 19 in the vicinity of the outer wiring portion 46 is suppressed, so that insulation breakdown between the pair of outer wiring portions 46 can be suppressed, The breakage of the ceramic heater 11 can be suppressed. Therefore, the reliability of the ceramic heater 11 can be improved.

(2) In the present embodiment, a pair of internal terminals 42 formed on the ceramic sheet 19 are disposed on the inner side of a pair of outer wiring portions 46 formed on the same ceramic sheet 19 Reference). Therefore, when the ceramic sheet 19 is wound around the outer periphery of the supporting body 17, the both internal terminals 42 are positioned on the opposite sides in the radial direction of the supporting body 17. [ As a result, since the distance between the both internal terminals 42 becomes large, the occurrence of the discharge between the both internal terminals 42 can be suppressed.

[Second Embodiment]

Hereinafter, a second embodiment embodying the present disclosure will be described with reference to the drawings. Here, the description will be focused on a part different from the first embodiment. In the present embodiment, the structure of the heater wiring is different from that of the first embodiment.

More specifically, as shown in the ceramic sheet 61 of Fig. 6, the outer wiring portion 63 constituting the heater wiring 62 has a line width W4 of 0.64 mm at the central portion 64, 0.66 mm at the central portion 64, The line width W5 of the portion 65 different from the line width W5 is set to 0.60 mm and the thickness is set to 15 mu m. Here, the &quot; central portion 64 of the outer wiring portion 63 &quot; refers to a region occupying not more than one-third of the length of the outer wiring portion 63 in the central portion of the outer wiring portion 63. [ The inner wiring portion 66 constituting the heater wiring 62 is set to have a line width W6 of 0.60 mm and a thickness of 15 mu m. In addition, the connection portion 67 constituting the heater wiring 62 is also set to have a line width W7 of 0.60 mm and a thickness of 15 mu m. That is, the line width W4 of the central portion 64 of the outer wiring portion 63 is equal to the line width W5 of the other portion 65 of the outer wiring portion 63, the line width W6 of the inner wiring portion 66, Is larger than the line width (W7) of the electrode (67). More specifically, the line width W4 of the central portion 64 is set to 1.1 times the line width W5 of the other portion 65, the line width W6 of the inner wiring portion 66, and the line width W7 of the connection portion 67 . Since the thickness of the central portion 64 is equal to the thickness of the other portion 65, the thickness of the inner wiring portion 66 and the thickness of the connecting portion 67, The cross-sectional area of the inner wiring portion 66, and the cross-sectional area of the connection portion 67 are larger. The line width of the outer wiring portion 63 is gradually increased from the other portion 65 to the central portion 64 at the connection portion between the central portion 64 and the other portion 65. [

<Experimental Example>

Hereinafter, an experimental example for evaluating the performance of the ceramic heater of the present embodiment will be described.

First, a sample for measurement was prepared as follows. A ceramic heater having a line width at the center of the outer wiring portion of 0.60 mm, a line width of the inner wiring portion of 0.55 mm, and a ratio of the line width of the center portion to the line width of the inner wiring portion of 1.09 was prepared. Respectively. A ceramic heater such as a ceramic heater of the present embodiment, which has a line width of 0.66 mm at the central portion, 0.60 mm of the line width of the inner wiring portion, and a ratio of 1.1, was prepared and used as a sample 1D '. Further, a ceramic heater having a line width of 0.69 mm at the center portion, a line width of 0.60 mm at the inner wiring portion, and a ratio of 1.15 was prepared and used as a sample 1E '. A ceramic heater having a line width at the center portion of 1.20 mm, a line width of the inner wiring portion of 0.60 mm, and a ratio of 2.0 was prepared and used as a sample 1F '. In addition, five samples 1C 'to 1F' were prepared.

Then, a voltage (alternating current of 240 V) was applied between the pair of internal terminals of each measurement sample (samples 1C 'to 1F') for 6 minutes, and the surface temperature of the ceramic sheet was measured with a thermocouple. It was also observed whether or not local heat generation in the outer wiring portion and insulation breakdown between the pair of outer wiring portions occurred. Table 2 shows the above results.

Sample Line width Test result The central portion (W4) The inner wiring portion (W6) The ratio (W4 / W6) Local fever Dielectric breakdown 1C ' 0.60mm 0.55mm 1.09 0/5 0/5 1D ' 0.66mm 0.60mm 1.1 0/5 0/5 1E ' 0.69mm 0.60mm 1.15 0/5 0/5 1F ' 1.20mm 0.60mm 2.0 0/5 0/5

As a result, all of the five samples were observed for 6 minutes in Samples 1C 'to 1F', but no occurrence of local heating or dielectric breakdown was observed. In the samples 1D 'and 1E', it was confirmed that the central portion of the outer wiring portion was slightly lowered, but not so much as to adversely affect the cracking property of the ceramic sheet.

As described above, when the line width of the center portion of the pair of outer wiring portions located on the opposite sides with respect to the joint portion is set to 1.09 times or more and 2.0 times or less of the line width of the inner wiring portion disposed between the pair of outer wiring portions, Heat generation and insulation breakage are less likely to occur, and cracking resistance is also less likely to deteriorate.

Therefore, by making the line width W4 of the central portion 64 of the outer wiring portion 63 larger than the line width W6 of the inner wiring portion 66, the electrical resistance of the central portion 64 can be reduced, Becomes smaller than the electric resistance of the portion (66). Therefore, local heat generation of the heater wiring 62 can be suppressed at the junction portion of the ceramic sheet 61 where the outer wiring portion 63 is located. As a result, since melting of the glass component present in the ceramic sheet 61 in the vicinity of the central portion 64 of the outer wiring portion 63 is suppressed, insulation breakdown between the pair of outer wiring portions 63 is suppressed And breakage of the ceramic heater can be suppressed. Therefore, the reliability of the ceramic heater can be improved.

[Third embodiment]

Hereinafter, a ceramic heater according to a third embodiment embodying the present disclosure and a method of manufacturing the same will be described with reference to the drawings.

The ceramic heater 111 of the present embodiment is used for warming the washing water in, for example, a heat exchanger of a heat exchange unit of a hot water washing seat.

7 and 8, the ceramic heater 111 includes a cylindrical ceramic heater body 113 and a metal annular flange 115 which is fitted outside the heater body 113 . The flange 115 is an annular member formed by bending a metal plate made of, for example, stainless steel, and has a concave (cup-shaped) central portion.

8, a space surrounded by the outer peripheral surface 114 of the heater body 113 and the inner surface of the flange 115 out of the concave portions of the flange 115 is formed in the glass storage portion 135, . The glass storage portion 135 is filled with a glass 133 and the heater body 113 and the flange 115 are welded and fixed via the glass 133. [ In Fig. 8, the portion of the glass 133 is hatched.

7 to 9, the heater main body 113 is constituted by a ceramic support 117 made of a cylindrical shape and a ceramic sheet 119 wound around the periphery of the support 117. In the present embodiment, the support 117 and the ceramic sheet 119 are made of ceramics such as alumina (Al ₂ O ₃ ). The thermal expansion coefficient of alumina is in the range of 50 x 10 ^-7 / K to 90 x 10 ^-7 / K, and in this embodiment, it is set to 70 x 10 ^-7 / K (30 to 380 캜). In this embodiment, the outer diameter of the support body 117 is set to 12 mm, the inner diameter is set to 8 mm, and the length is set to 65 mm, and the thickness of the ceramic sheet 119 is set to 0.5 mm and the length to 60 mm. Further, the ceramic sheet 119 does not completely cover the outer periphery of the support 117. Therefore, a slit 121 extending along the axial direction of the support body 117 and exposing the outer peripheral surface of the support body 117 is formed in the joint portion 120 of the ceramic sheet 119. The slit 121 of this embodiment is set to have a width of 1 mm and a depth of 0.5 mm.

As shown in Figs. 9 and 10, a heater wire 141 and a pair of internal terminals 142 are formed in the ceramic sheet 119 in the shape of a meandering pattern. In the present embodiment, the heater wiring 141 and the pair of internal terminals 142 include tungsten (W) as a main component. Each of the internal terminals 142 is electrically connected to an external terminal 143 (see FIG. 7) formed on the outer circumferential surface of the ceramic sheet 119 through a via conductor (not shown).

The heater wiring 141 is provided with a plurality of wiring portions 144 extending along the axial direction of the supporting body 117 and a connecting portion 145 connecting the adjacent wiring portions 144 with each other. The plurality of wiring portions 144 are provided with a pair of outer wiring portions 146 and a plurality of inner wiring portions 147. A pair of outer wiring portions 146 are disposed on the opposite sides of the ceramic sheet 119 with the joint portion 120 (see Fig. 9) interposed therebetween. The first end (upper end in Fig. 10) of the outer wiring portion 146 is connected to the inner terminal 142 and the second end (lower end in Fig. 10) of the outer wiring portion 146 is connected to the inner side And is connected to the wiring portion 147. Each of the internal terminals 142 is disposed between the pair of outer wiring portions 146 when the ceramic sheet 119 is viewed in the thickness direction.

As shown in Figs. 9 and 10, each inner wiring portion 147 is disposed between a pair of outer wiring portions 146 in the ceramic sheet 119. The first end (upper end in FIG. 10) of the inner wiring portion 147 is connected to the first end of the adjacent inner wiring portion 147 via the connection portion 145. The second end (lower end in Fig. 10) of the inner wiring portion 147 is connected to the second end of the adjacent inner wiring portion 147 or the second end of the adjacent outer wiring portion 146 via the connecting portion 145 Respectively.

In addition, the outer wiring portion 146 of this embodiment has a thickness T1 of 20 mu m and a line width of 0.60 mm. The inner wiring portion 147 of the present embodiment has a thickness T2 of 15 mu m and a line width of 0.60 mm. Similarly, the connection portion 145 of this embodiment is also set to have a thickness of 15 mu m and a line width of 0.60 mm. That is, the thickness T1 of the outer wiring portion 146 is larger than the thickness T2 of the inner wiring portion 147 and the thickness of the connection portion 145. More specifically, the thickness T1 of the outer wiring portion 146 is set to 1.33 times the thickness T2 of the inner wiring portion 147 and the thickness of the connection portion 145. [ The thickness T2 of the inner wiring portion 147 is equal to the thickness of the connection portion 145. [ The sectional area of the outer wiring portion 146 is larger than the sectional area of the inner wiring portion 147 and the sectional area of the connection portion 145. [ Is larger than the cross-sectional area of the second electrode 145.

Next, a method of manufacturing the ceramic heater 111 of the present embodiment will be described.

First, a clay-shaped slurry containing alumina as a main component is put into a conventionally known extruder (not shown) to form a tubular member. Then, after the molded tubular member is dried, the support 117 (see Fig. 11A) is obtained by performing the plasticity by heating at a predetermined temperature (for example, about 1000 캜).

In addition, the first and second ceramic green sheets 151 and 152 serving as the ceramic sheet 119 are formed by using a ceramic material containing alumina powder as a main component. As a method of forming the ceramic green sheet, a well-known forming method such as a doctor blade method can be used.

Then, a printing process is performed. That is, a conductive paste (tungsten paste in this embodiment) is printed on the surface of the first ceramic green sheet 151 by using a conventionally known paste printing apparatus (not shown). In the present embodiment, the conductive paste is printed in two divided portions, so that the thickness T1 of the outer wiring portion 146 is made thicker than the thickness T2 of the inner wiring portion 147. [ First, a conductive paste is printed on the surface of the first ceramic green sheet 151 to form a first electrode 153 which is a non-fired electrode constituting the heater wiring 141 and the internal terminal 142, (See Fig. 11B). The line width of the first electrode 153 is adjusted to be, for example, the line width of the heater wiring 141 plus the shrinkage at the time of firing. Next, a step of printing a conductive paste on a portion of the first electrode 153 which becomes the outer wiring portion 146 to form a second electrode 154 constituting a part of the outer wiring portion 146 (See FIG. 11B). Although not shown, the line width of the second electrode 154 is adjusted to be narrower than that of the first electrode 153, for example.

After the electroconductive paste is dried, a second ceramic green sheet 152 is laminated on the printing surface of the first ceramic green sheet 151 (forming surface of the first electrode 153 and the second electrode 154) Thereby applying pressure to the sheet stacking direction. As a result, the first and second ceramic green sheets 151 and 152 are integrated to form a green sheet laminate 155 (see FIG. 11C). Further, a conductive paste is printed on the surface of the second ceramic green sheet 152 using a paste printing apparatus. As a result, on the surface of the second ceramic green sheet 152, the unfired electrode 156 to be the external terminal 143 is formed.

Then, a winding process is carried out. That is, ceramic paste (alumina paste) is applied to one side of the green sheet laminate 155, and the green sheet laminate 155 is wound around the outer periphery of the support 117 and adhered thereto (see FIG. At this time, the size of the green sheet laminated body 155 is adjusted so that the ends of the green sheet laminated body 155 do not overlap each other. Then, the green sheet laminate 155 (the first and second ceramic green sheets 151 and 152, the first electrode 153, the second electrode 153, (For example, about 1400 DEG C to about 1600 DEG C) at which sintering of alumina and tungsten in the sintered body (sintered body 154 and untreated electrode 156) can be sintered. As a result, alumina in the first and second ceramic green sheets 151 and 152 and tungsten in the conductive paste are sintered simultaneously to form the green sheet laminate 155 as the ceramic sheet 119, The electrodes 153 and 154 serve as the heater wiring 141 and the internal terminal 142 and the untreated electrode 156 serves as the external terminal 143. [ Thereafter, the external terminal 143 is plated with nickel to form the heater main body 113.

Then, a plate material made of stainless steel is press-formed by using a metal mold to form a cup-shaped flange 115. Then, the flange 115 is fitted outside at a predetermined mounting position of the heater body 113. Thereafter, the heater body 113 and the flange 115 are welded and fixed via the glass 133 to complete the ceramic heater 111.

<Experimental Example>

Hereinafter, an experimental example for evaluating the performance of the ceramic heater 111 of the present embodiment will be described.

First, a sample for measurement was prepared as follows. The thickness of the outer wiring portion is 15 占 퐉, the thickness of the inner wiring portion is 15 占 퐉, and the ratio of the thickness of the outer wiring portion to the thickness of the inner wiring portion is 1.0, in other words, A ceramic heater having a thickness equal to the thickness of the inner wiring portion was prepared, and this was designated Sample 2A. A ceramic heater having a thickness of the outer wiring portion of 18 mu m, a thickness of the inner wiring portion of 15 mu m, and a ratio of 1.2 was prepared and used as a sample 2B. A ceramic heater having a thickness of the outer wiring portion of 15 mu m, a thickness of the inner wiring portion of 12 mu m, and a ratio of 1.25 was prepared and used as Sample 2C. A ceramic heater having a thickness of the outer wiring portion of 19 mu m, a thickness of the inner wiring portion of 15 mu m, and a ratio of 1.27 was prepared and used as a sample 2D. A ceramic heater such as the ceramic heater 111 of the present embodiment having the thickness of the outer wiring part of 20 mu m, the thickness of the inner wiring part of 15 mu m and the ratio of 1.33 was prepared and was then put into a sample 2E Respectively. A ceramic heater having a thickness of the outer wiring portion of 25 mu m, a thickness of the inner wiring portion of 15 mu m, and a ratio of 1.67 was prepared and used as a sample 2F. A ceramic heater having a thickness of the outer wiring portion of 30 mu m, a thickness of the inner wiring portion of 15 mu m, and a ratio of 2.0 was prepared and used as a sample 2G. A ceramic heater having a thickness of the outer wiring portion of 36 mu m, a thickness of the inner wiring portion of 15 mu m, and a ratio of 2.4 was prepared, and this was designated as Sample 2H. In addition, five samples 2A to 2H were prepared.

Then, nichrome wires were soldered to a pair of internal terminals (heater wires) included in the ceramic sheets of the respective measurement samples (samples 2A to 2H), and the measurement samples were set in a dry state and placed on the base. Then, a voltage (alternating current of 240 V) was applied between the pair of internal terminals for 6 minutes, and the surface temperature of the ceramic sheet was measured with a thermocouple. It was observed whether or not local heat generation in the outer wiring portion and insulation breakdown between the pair of outer wiring portions occurred, and in the case of insulation breakage, the time of occurrence thereof was measured and recorded. Table 3 shows the above results.

Sample thickness Test result The outer wiring portion (T1) The inner wiring portion (T2) The ratio (T1 / T2) Local fever Dielectric breakdown 2A 15 탆 15 탆 1.0 5/5 5/5 2B 18 탆 15 탆 1.2 5/5 2/5 2C 15 탆 12 탆 1.25 1/5 0/5 2D 19 탆 15 탆 1.27 0/5 0/5 2E 20 탆 15 탆 1.33 0/5 0/5 2F 25 m 15 탆 1.67 0/5 0/5 2G 30 탆 15 탆 2.0 0/5 0/5 2H 36 탆 15 탆 2.4 0/5 0/5

As a result, it was confirmed that, in Sample 2A, local exothermic heat was generated in all five samples, and sparks occurred after 1 minute and 50 seconds to cause dielectric breakdown. In Sample 2B, it was confirmed that local exothermic heat occurred in all five samples and insulation breakdown occurred in two of five samples. In addition, in Sample 2C, no occurrence of dielectric breakdown was confirmed, but it was confirmed that localized heat was generated in one sample out of the five. On the other hand, in the samples 2D to 2H, all five samples were observed for 6 minutes, but local heat generation and insulation breakdown were not observed. However, in the sample 2H, it was confirmed that the bonding portion of the ceramic sheet becomes low temperature and the cracking property is lowered.

As described above, if the thickness of the pair of outer wiring portions located on opposite sides with the joint portion interposed therebetween is set to 1.27 times or more and 2.0 times or less the thickness of the inner wiring portion disposed between the pair of outer wiring portions, And insulation breakdown is less likely to occur, and cracking resistance is less likely to be lowered.

Therefore, according to the present embodiment, the following effects can be obtained.

(1) In the ceramic heater 111 of the present embodiment, the thickness T1 of the outer wiring portion 146 is made larger than the thickness T2 of the inner wiring portion 147, so that the electrical resistance of the outer wiring portion 146 Becomes smaller than the electric resistance of the inner wiring portion 147. [ Therefore, it is possible to suppress the local heat generation of the heater wiring 141 in the joint portion 120 where the outer wiring portion 146 is located. As a result, since the melting of the glass components present in the ceramic sheet 119 in the vicinity of the outer wiring part 146 is suppressed, insulation breakdown between the pair of outer wiring parts 146 can be suppressed, Breakage of the ceramic heater 111 can be suppressed. Therefore, the reliability of the ceramic heater 111 can be improved.

(2) In the present embodiment, a pair of internal terminals 142 formed on the ceramic sheet 119 are disposed on the inner side of a pair of outer wiring portions 146 formed on the same ceramic sheet 119 Reference). Therefore, when the ceramic sheet 119 is rolled around the outer periphery of the supporting body 117, the both internal terminals 142 are positioned on the opposite sides in the radial direction of the supporting body 117. As a result, since the distance between the both internal terminals 142 becomes large, the occurrence of the discharge between the both internal terminals 142 can be suppressed.

(3) In the present embodiment, since the electrical resistance of the outer wiring portion 146 is made small without forming the outer wiring portion 146 at a wide width, the electrical resistance of the outer wiring portion 146 is reduced, It becomes easy to secure the distance between the pair of outer wiring parts 146. [ Therefore, the occurrence of the partial discharge between the two outer wiring portions 146 can be suppressed more reliably.

[Fourth Embodiment]

Hereinafter, a fourth embodiment embodying the present disclosure will be described with reference to the drawings. Here, differences from the third embodiment will be mainly described. In this embodiment, the structure of the heater wiring is different from that of the third embodiment.

12 and 13, the outer wiring portion 163 constituting the heater wiring 162 of the ceramic sheet 161 is formed so that the thickness T3 of the central portion 164 is 20 mu m, The thickness of the portion 165 different from the center portion 164 is set to 15 mu m and the line width is set to 0.60 mm. Here, the "central portion 164 of the outer wiring portion 163" refers to a region occupying not more than one-third of the length of the outer wiring portion 163 in the central portion of the outer wiring portion 163. The inner wiring portion 166 constituting the heater wiring 162 has a thickness T4 of 15 占 퐉 and a line width of 0.60 mm. In addition, the connection portion 167 constituting the heater wiring 162 is also set to have a thickness of 15 mu m and a line width of 0.60 mm. The thickness T3 of the central portion 164 of the outer wiring portion 163 is equal to the thickness T4 of the other portion 165 of the outer wiring portion 163 and the thickness T4 of the inner wiring portion 166, As shown in Fig. More specifically, the thickness T3 of the central portion 164 is set to 1.33 times the thickness of the other portion 165, the thickness T4 of the inner wiring portion 166, and the thickness of the connection portion 167. Since the line width of the central portion 164 is equal to the line width of the other portion 165, the line width of the inner wiring portion 166 and the line width of the connection portion 167, The cross-sectional area of the inner wiring portion 166, and the cross-sectional area of the connection portion 167 are larger.

In the present embodiment, the conductive paste is divided into two prints so that the thickness T3 of the central portion 164 is made larger than the thickness T4 of the inner wiring portion 166. In detail, first, a conductive paste is printed on the surface of the ceramic green sheet to be the ceramic sheet 161 to form a first electrode which is an unfired electrode constituting the heater wiring 162. Then, a step of printing a conductive paste on a portion of the first electrode that becomes the central portion 164 to form a second electrode constituting a part of the central portion 164 is performed. Although not shown, the line width of the second electrode is adjusted to be narrower than, for example, the first electrode. Thereafter, the ceramic green sheet becomes the ceramic sheet 161, a part of the region where the first electrode is formed becomes the inner wiring portion 166, and the region where the first and second electrodes are formed is the inner side The central portion 164 becomes thicker than the wiring portion 166. [

<Experimental Example>

Hereinafter, an experimental example for evaluating the performance of the ceramic heater of the present embodiment will be described.

First, a sample for measurement was prepared as follows. A ceramic heater having a thickness of the center portion of the outer wiring portion of 15 mu m, a thickness of the inner wiring portion of 12 mu m, and a thickness ratio of the center portion to the thickness of the inner wiring portion of 1.25 was prepared, Respectively. A ceramic heater such as the ceramic heater of the present embodiment, which had a thickness of the center portion of 20 mu m, a thickness of the inner wiring portion of 15 mu m and a ratio of 1.33, was prepared and used as a sample 2E '. Further, a ceramic heater having a thickness of 25 mu m at the central portion, a thickness of 15 mu m at the inner wiring portion, and a ratio of 1.67 was prepared and used as a sample 2F '. A ceramic heater having a thickness of 30 mu m at the central portion, a thickness of 15 mu m at the inner wiring portion, and a ratio of 2.0 was prepared and used as a sample 2G '. In addition, five samples 2C 'and 2E' to 2G 'were prepared.

Then, a voltage (alternating current of 240V) was applied between a pair of internal terminals provided for each of the measurement samples (samples 2C ', 2E' to 2G ') for 6 minutes, and the surface temperature of the ceramic sheet was measured with a thermocouple . It was also observed whether or not local heat generation in the outer wiring portion and insulation breakdown between the pair of outer wiring portions occurred. Table 4 shows the above results.

Sample thickness Test result The central portion (T3) The inner wiring portion (T4) The ratio (T3 / T4) Local fever Dielectric breakdown 2C ' 15 탆 12 탆 1.25 0/5 0/5 2E ' 20 탆 15 탆 1.33 0/5 0/5 2F ' 55 탆 15 탆 1.67 0/5 0/5 2G ' 30 탆 15 탆 2.0 0/5 0/5

As a result, all of the five samples were observed for 6 minutes in the samples 2C 'and 2E' to 2G ', but no occurrence of local heating or dielectric breakdown was observed. In the samples 2E 'to 2G', it was confirmed that the central portion of the outer wiring portion was slightly lowered in temperature, but not so much as to adversely affect the cracking property of the ceramic sheet.

In view of the above, if the thickness of the central portion of the pair of outer wiring portions positioned on opposite sides of the junction portion is set to 1.25 times or more and 2.0 times or less of the thickness of the inner wiring portion disposed between the pair of outer wiring portions, Heat generation and insulation breakage are less likely to occur, and cracking resistance is also less likely to deteriorate.

Therefore, by making the thickness T3 of the central portion 164 of the outer wiring portion 163 larger than the thickness T4 of the inner wiring portion 166 according to the present embodiment, The electric resistance of the portion 166 becomes smaller. This makes it possible to suppress local heat generation of the heater wiring 162 at the joint portion 168 of the ceramic sheet 161 where the outer wiring portion 163 is located. As a result, since melting of the glass component present in the ceramic sheet 161 in the vicinity of the central portion 164 of the outer wiring portion 163 is suppressed, insulation breakdown between the pair of outer wiring portions 163 is suppressed And breakage of the ceramic heater can be suppressed. Therefore, the reliability of the ceramic heater can be improved.

[Other Embodiments]

The above embodiment may be modified as follows.

In the first embodiment, the line width W3 of the connection portion 45 may be made larger than the line width W1 of the outer wiring portion 46 and the line width W2 of the inner wiring portion 47. [ The line width W7 of the connecting portion 67 is the same as the line width W4 of the central portion 64 of the outer wiring portion 63 and the line width W2 of the other portion 65 of the outer wiring portion 63 The line width W6 of the inner wiring portion 66 and the line width W5 of the inner wiring portion 66 may be larger.

In the second embodiment, one central portion 64 is formed in one outer wiring portion 63. However, two or more wide portions having the same line width as the center portion 64 may be formed in one outer wiring portion. When two or more wider portions are formed in one outer wiring portion, the wider portions may be disposed apart from each other along the direction in which the outer wiring portions extend, and are arranged in contact with each other along the direction in which the outer wiring portions extend There may be.

In the above embodiment, the supporting body 17 of the ceramic heater 11 and the supporting body 117 of the ceramic heater 111 have a cylindrical shape, but the supporting body may have a bar shape. That is, the ceramic heater may be used for something different from the hot water washing unit (for example, a fan heater, etc.). Although a flange made of stainless steel is used in the above embodiment, for example, a flange made of alumina may be used.

Although the ceramic heater 11 and the ceramic heater 111 of the above-described embodiment are such that an AC voltage is applied between a pair of internal terminals 42 and a pair of internal terminals 142, A direct current voltage may be applied between the pair of inner terminals 142 and the pair of inner terminals 142. [

In the third embodiment, the thickness T1 of the outer wiring portion 146 is made larger than the thickness T2 of the inner wiring portion 147 by printing the conductive paste in two divided portions. However, when the conductive paste is applied three times or more The thickness T1 of the outer wiring portion 146 may be made thicker than the thickness T2 of the inner wiring portion 147. [ Similarly, in the fourth embodiment, the thickness T3 of the central portion 164 is made thicker than the thickness T4 of the inner wiring portion 166 by printing the conductive paste in two divided portions. However, The thickness T3 of the central portion 164 may be made larger than the thickness T4 of the inner wiring portion 166 by dividing and printing.

In the third embodiment, a conductive paste is printed on the surface of the first ceramic green sheet 151 to form a substantially smear (a region excluding the upper layer portion of the outer wiring portion 146) of the heater wiring 141 After forming the sextupole (the first electrode 153), conductive paste is printed on the portion of the first electrode 153 that becomes the outer wiring portion 146 to constitute the upper layer portion of the outer wiring portion 146 Unfired electrode (second electrode 154) is formed. However, after the unbaked electrode constituting the lower layer portion of the outer wiring portion 146 is formed by printing the conductive paste on the portion of the first ceramic green sheet 151 which becomes the outer wiring portion 146, The conductive paste is printed on the surface of the unbaked electrode sheet and the first ceramic green sheet 151 to form substantially the entirety of the heater wiring 141 (a region excluding the lower layer portion of the outer wiring portion 146) May be formed. The entirety of the heater wiring 141 may be formed by printing the conductive paste only once using an inkjet apparatus or the like.

In the fourth embodiment, an electrically conductive paste is printed on the surface of the ceramic green sheet to form an unbaked electrode (first electrode) constituting almost the whole of the heater wiring 162 (a region excluding the upper layer portion of the central portion 164) An unbaked electrode (second electrode) constituting an upper layer portion of the center portion 164 is formed by printing a conductive paste on a portion of the first electrode that becomes the central portion 164. However, after the conductive paste is printed on the surface of the ceramic green sheet to be the central portion 164 to form the unfired electrode constituting the lower portion of the central portion 164, the unbaked electrode surface and the ceramic green sheet A conductive paste may be printed on the surface to form unbaked electrodes constituting substantially the entirety of the heater wiring 162 (a region excluding the lower layer portion of the central portion 164). In addition, the entire heater wiring 162 may be formed by printing the conductive paste only once using an ink-jet apparatus or the like.

In the third embodiment, the line width of the second electrode 154 to be the outer wiring portion 146 is adjusted to be narrower than the width of the first electrode 153 to be the same outer wiring portion 146. However, The line width of the electrode 154 may be the same as that of the first electrode 153 and the line width of the second electrode 154 may be wider than that of the first electrode 153. [ Similarly, in the fourth embodiment, the line width of the second electrode serving as the center portion 164 is adjusted so as to be narrower than that of the first electrode serving as the center portion 164, but the line width of the second electrode may be set to be the same width Or the line width of the second electrode may be made wider than that of the first electrode.

Here, the correspondence relationship between words will be described.

In the above-described embodiment, the ceramic heaters 11 and 111 correspond to examples of the ceramic heaters, the supports 17 and 117 correspond to examples of the supports, and the ceramic sheets 19, 61, 119, Each correspond to an example of the ceramic sheet.

The heater wirings 41, 62, 141, and 162 correspond to examples of the heater wirings and the wiring portions 44 and 144 correspond to an example of the wiring portion And the connection portions 45, 67, 145, and 167 correspond to examples of the connection portions, respectively.

The inner wiring portions 47, 66, 147, and 166 correspond to examples of the inner wiring portions, and the central portions 64 (64, 63, 146, and 163) of the outer wiring portions correspond to one example of the outer wiring portions, And 164 correspond to examples of the central portion of the outer wiring portion, respectively.

[Other technical ideas]

Next, the technical ideas that are grasped by the above embodiments in addition to the technical ideas described in the claims are listed below.

(1) A ceramic heater in which the line width of the outer wiring part is larger than the line width of the inner wiring part, or the line width of the center part of the outer wiring part is larger than the line width of the inner wiring part, wherein the line width of the outer wiring part is 1.09 And more preferably not less than 1.1 times and not more than 2.0 times the line width of the inner wiring portion.

(2) The ceramic heater according to (2), wherein the line width of the center portion of the outer wiring portion is larger than the line width of the inner wiring portion, wherein the line width of the center portion is thicker than the line width of the other wiring portion.

(3) A ceramic heater in which the thickness of the central portion of the outer wiring portion is thicker than the thickness of the inner wiring portion, characterized in that the thickness of the central portion is thicker than the thickness of the portion other than the central portion of the outer wiring portion heater.

(4) A method of manufacturing a ceramic heater having a configuration in which the thickness of the outer wiring portion is thicker than the thickness of the inner wiring portion, the method comprising: a printing step of forming the heater wiring by printing a conductive paste on the ceramic sheet; And a winding step of winding the ceramic sheet on the supporting member, wherein in the printing step, the conductive paste is divided into a plurality of circuits and printed so that the thickness of the outer wiring portion is made thicker than the thickness of the inner wiring portion .

(5) In the technical idea (4), the printing step includes the steps of: forming a first electrode constituting the heater wiring on the ceramic sheet; and forming, on the first wiring, And forming a second electrode having a width narrower than that of the one electrode.

(6) A method for manufacturing a ceramic heater having a thickness of a central portion of an outer wiring portion greater than a thickness of an inner wiring portion, the method comprising: a printing step of forming the heater wiring by printing a conductive paste on the ceramic sheet; And a winding step of winding the printed ceramic sheet on the support, wherein in the printing step, the conductive paste is divided into a plurality of circuits and printed so that the thickness of the central portion is made thicker than the thickness of the inner wiring portion Way.

(7) A technical idea (6), wherein the printing step comprises the steps of: forming a first electrode constituting the heater wiring on the ceramic sheet; and forming a second electrode on the first electrode, And forming a second electrode having a width narrower than that of the electrode.

11 - Ceramic heater 17 - Support
19, 61 - Ceramic sheet 20 - Joint
41, 62 - heater wiring 44 - wiring part
45, 67 - connecting portion 46, 63 - outer wiring portion
47, 66 - Inner wiring part 64 - Center part of the outer wiring part
W1 - Width of outer wiring part W2, W6 - Width of inner wiring part
W4 - Width across the center 111 - Ceramic heater
117 - Support 119, 161 - Ceramic sheet
120, 168 - junction 141, 162 - heater wiring
144 - wiring part 145, 167 - connection part
146, 163 - outer wiring parts 147, 166 - inner wiring part
164 - the center of the outer wiring part T1 - the thickness of the outer wiring part
T2, T4 - Thickness of inner wiring part T3 - Thickness of center part

Claims (12)

A ceramic heater comprising: a support made of ceramic; and a ceramic sheet wound around the periphery of the support and having a heater wiring,
The heater wiring includes a plurality of wiring portions extending along the axial direction of the support and connection portions connecting the adjacent wiring portions,
Wherein the plurality of wiring portions include a pair of outer wiring portions disposed on opposite sides of a junction of the ceramic sheets with each other, and an inner wiring portion disposed between the pair of outer wiring portions in the ceramic sheet,
Wherein a cross-sectional area of the outer wiring portion is larger than a cross-sectional area of the inner wiring portion.
The method according to claim 1,
And the line width of the outer wiring portion is larger than the line width of the inner wiring portion.
The method of claim 2,
Wherein a line width of said outer wiring portion is set to be larger than or equal to 1.07 times the line width of said inner wiring portion and less than 2.4 times.
The method according to claim 1,
Wherein a thickness of the outer wiring portion is thicker than a thickness of the inner wiring portion.
The method of claim 4,
Wherein a thickness of the outer wiring portion is set to be larger than 1.25 times the thickness of the inner wiring portion and less than 2.4 times the thickness of the inner wiring portion.
A ceramic heater comprising: a support made of ceramic; and a ceramic sheet wound around the periphery of the support and having a heater wiring,
The heater wiring includes a plurality of wiring portions extending along the axial direction of the support and connection portions connecting the adjacent wiring portions,
Wherein the plurality of wiring portions include a pair of outer wiring portions disposed on opposite sides of a junction of the ceramic sheets with each other, and an inner wiring portion disposed between the pair of outer wiring portions in the ceramic sheet,
Sectional area of the central portion of the outer wiring portion is larger than a cross-sectional area of the inner wiring portion.
The method of claim 6,
Wherein the line width of the central portion of the outer wiring portion is larger than the line width of the inner wiring portion.
The method of claim 7,
Wherein a line width of the center portion is set to be larger than or equal to 1.07 times the line width of the inner wiring portion and to be set to 2.0 times or less.
The method of claim 6,
Wherein the thickness of the central portion of the outer wiring portion is thicker than the thickness of the inner wiring portion.
The method of claim 9,
Wherein the thickness of the central portion is set to be not less than 1.25 times and not more than 2.0 times the thickness of the inner wiring portion.
The method according to any one of claims 1 to 10,
Wherein the support and the ceramic sheet comprise alumina.
The method according to any one of claims 1 to 11,
Wherein the heater wiring includes at least one of tungsten and molybdenum as a main component.

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