JP4818922B2 - Manufacturing method of ceramic heater - Google Patents

Description

The present invention, the sensor heater, in particular an air-fuel ratio sensor heating for motor vehicles, vaporization dexterity heater, hair iron, a method for manufacturing a ceramic heater for use such as a soldering iron.

Conventionally, an alumina ceramic heater in which a heating resistor made of a high melting point metal such as W, Re, or Mo is embedded in ceramics mainly composed of alumina has been widely used.
For example, when manufacturing a cylindrical ceramic heater, a ceramic molded body 12 and a ceramic green sheet 13 are prepared as shown in FIG. 10, and a high melting point such as W, Re, or Mo is formed on one surface of the ceramic green sheet 13. After forming the heat generating resistor 14 and the lead lead portion 15 made of metal and forming the electrode pad on the back surface (the other surface) (not shown), the ceramic is formed so that the heat generating resistor 14 and the lead lead portion 15 are inside. It is wound around the compact 12 and fired in close contact. In addition, the lead extraction part 15 and the electrode pad are connected by the through hole 16 formed in the ceramic green sheet 13 (for example, refer patent document 1).

  Thus, the conventional ceramic heater is formed by simultaneously firing the paste-like heating resistor 14 together with the ceramic molded body 12 and the ceramic green sheet 13. And the heating resistor of the ceramic heater made in this way has a bent shape that is folded back multiple times (FIG. 1 of Patent Document 2, etc.).

  In Patent Documents 3 to 5, the bases of a pair of gripping members are connected to be freely opened and closed by shafts, and the distal ends of both gripping members are always opened by a biasing force of a spring provided on the bearing unit. A hair iron provided with a heater plate inside the opening at the tip of both gripping members is disclosed.

The hair iron or by fitting the heater plate covered with an insulating plate on both sides by winding a nichrome wire to the ceramic insulating plate to plate-heat the plate-like body from the heater plate is pressed by the leaf spring It was a structure to convey to.
JP 2001-126852 A JP 2001-102156 A Japanese Patent Laid-Open No. 2000-232911 JP 2002-291517 A JP 2000-14438 A

However, recently, ceramic heaters have been used in higher temperature environments, and this has caused a problem of reduced durability. That is, when continuous energization at a high temperature is performed, the insulation between adjacent patterns deteriorates and the durability deteriorates, eventually causing a problem of causing a spark or disconnection. .
In addition, a heater made by winding a heating element made of nichrome wire around an insulating plate is disconnected by repeated heating and energizing, or the heating element reacts with moisture in the air to form a reaction layer, and the resistance of the heating element There is a problem that the value becomes large, the predetermined temperature may not be reached at a predetermined voltage, and the durability is inferior.

  Further, the heater plate made of nichrome wire has a problem that it is difficult to uniformly dispose the heating element on the heater plate, and the heating surface of the plate-like body cannot be heated uniformly.

In addition, since the heating surface of the heater plate and the surface of the plate-like body are not in uniform thermal contact, it is difficult to uniformly transfer the heat of the heater plate to the plate-like body. There was a problem that it could not be made uniform.
The present invention has been made in view of the above circumstances and purpose thereof is to provide a method for producing good ceramic heater of preventing durability reduced insulation at high temperatures.

Manufacturing method of a ceramic heater according to the present invention,
Forming a conductive paste in a predetermined pattern on the surface of the first ceramic green sheet;
The surface of the first ceramic green sheet on which the conductive paste is formed has at least the same thickness as the conductive pattern, is more flexible than the first ceramic green sheet, and has a diameter of 1 mm when measured with a digital indicator. A step of producing a ceramic green sheet laminate by laminating a second ceramic green sheet having a hardness of 200 μm or more with which the needle penetrates in 30 seconds;
Winding the ceramic green sheet laminate around a cylindrical ceramic molded body and bonding together;
A step of firing the laminated ceramic green sheet laminate and the ceramic molded body is characterized.

The method for manufacturing a ceramic heater according to the present invention has a void occupancy ratio of the ceramic body between the conductors of the obtained ceramic heater of 0.01 to 50% , can prevent a decrease in insulation at a high temperature, and is durable. A high ceramic heater can be provided .

It is a partially broken perspective view which shows the structure of the reference form 1 of the ceramic heater obtained by the manufacturing method of the ceramic heater of this invention. It is sectional drawing about the XX line in the ceramic heater of FIG. It is sectional drawing which expands and shows between the conductors in the columnar ceramic heater of the reference form 1. It is sectional drawing which expands and shows between the conductors in the flat ceramic heater which concerns on the modification of the reference form 1. It is a partially notched side view which shows the structure of the hair iron of the reference form 2. FIG. It is a front view which shows the positional relationship of the heater plate used for the hair iron of FIG. 5, and a plate-shaped object. It is sectional drawing about the XX line of FIG. It is sectional drawing of the heating apparatus of the modification of the reference form 2 . It is a top view of the heater board used for the heating apparatus of the reference form 2 . It is an expanded view of the ceramic heater of a prior art example.

1: Ceramic heater,
2: Ceramic core,
3: Ceramic sheet,
4: Heating resistor,
5: Lead extraction part,
6: Through hole,
7: electrode pad,
8: Lead member,
A: Area between conductors in a cylindrical ceramic heater,
B: Area between conductors in the flat ceramic heater,
5: heating device,
50: gripping member,
52: axis,
53: Coil spring
54: Bearing part
55: plate-like body,
55a: heating surface,
57: heater plate,
58: Resistance heating element,
59: Spring,
61: lead wire,

Embodiments according to the present invention will be described below with reference to the drawings.
Reference form 1.
FIG. 1 is a partially broken perspective view showing a configuration of a reference embodiment 1 of a ceramic heater 1 obtained by the method for manufacturing a ceramic heater of the present invention, and FIG. 2 is a cross-sectional view taken along the line XX of FIG. is there.

The ceramic heater 1 of the reference form 1 includes a heating resistor 4 built in a ceramic body composed of a ceramic core material 2 and a ceramic sheet 3. Here, the heating resistor 4 is formed of a folded portion in the conductor pattern, and the void occupancy ratio of the ceramic body between adjacent conductors is 0.01 to 50% in the portion where the heating resistor 4 is formed. It is characterized by this.

  This ceramic heater 1 is composed of a ceramic green sheet (ceramic sheet 3 after firing) having a heating resistor 4 and a lead extraction portion 5 formed on the front surface and an electrode pad 7 formed on the back surface, and the heating resistor 4 and the lead extraction. It is obtained by wrapping around a ceramic molded body (ceramic core material 2 after firing) so that the portion 5 is on the inside and firing it closely. The lead lead portion 5 and the electrode pad 7 are connected by a through hole 6 formed in the ceramic sheet 3.

The ceramic body includes a ceramic core 2 formed by firing a ceramic molded body and a ceramic sheet 3 formed by firing a ceramic green sheet. This ceramic body is made of various ceramics such as alumina ceramics, silicon nitride ceramics, aluminum nitride ceramics, and silicon carbide ceramics. In particular, it is preferable to use alumina or silicon nitride as a main component, thereby rapidly increasing the ceramic body. The ceramic heater 1 excellent in temperature and durability can be obtained. For example, in the case of alumina ceramics, Al ₂ O ₃ is 88 to 95 wt%, SiO ₂ is ₂ to 7 wt%, CaO is 0.5 to 3 wt%, MgO is 0.5 to 3 wt%, and ZrO ₂ is 1 It is preferable to use a composition composed of ˜3% by weight. If the Al ₂ O ₃ content is less than 88% by weight, the vitreous content increases, and migration during energization may increase. On the other hand, when the Al ₂ O ₃ content exceeds 95% by weight, the amount of glass diffusing into the metal layer of the heating resistor 4 incorporated in the ceramic heater 1 decreases, and the durability of the ceramic heater 1 deteriorates. There is a fear. In the case of silicon nitride ceramics, 3 to 12% by weight of rare earth element oxide and 0.5 to 3% by weight of Al ₂ O ₃ as a sintering aid with respect to silicon nitride as a main component, It is preferable to mix SiO ₂ so that the amount of SiO ₂ contained is 1.5 to 5% by weight. The amount of SiO ₂ shown here is the sum of SiO ₂ generated from impurity oxygen contained in the silicon nitride raw material, SiO ₂ as impurities contained in other additives, and SiO ₂ intentionally added. . Further, by dispersing MoSi ₂ or WSi ₂ in the base material silicon nitride, the thermal expansion coefficient of the base material is brought close to the thermal expansion coefficient of the heating resistor 4, thereby improving the durability of the heating resistor 4. Is possible.

Further, the heating resistor 4 is constituted by a meandering conductor pattern, and a lead lead portion 5 formed to have a resistance value of about 1/10 is connected to the heating resistor 4. Usually, in order to simplify the work, the heating resistor 4 and the lead extraction portion 5 are often simultaneously printed on a ceramic green sheet (which becomes the ceramic sheet 3 after firing). Incidentally, in fold-back portion is intended to include shapes that the folded shape or serpentine into a U so that a desired resistance value.

  Here, the dimensions of the ceramic heater 1 can be, for example, about 2 to 20 mm in outer diameter or width and about 40 to 200 mm in length. The ceramic heater 1 for heating an air-fuel ratio sensor of an automobile preferably has an outer diameter or width of 2 to 4 mm and a length of 50 to 65 mm. Moreover, in the use for motor vehicles, it is preferable that the heat generation length of the heat generating resistor 4 is 3 to 15 mm. When the heat generation length is shorter than 3 mm, the temperature rise during energization can be accelerated, but the durability of the ceramic heater 1 is reduced. If the heat generation length is longer than 15 mm, the rate of temperature increase becomes slow, and if the rate of temperature increase is increased, the power consumption of the ceramic heater 1 increases, which is not preferable. The heat generation length is the length in the longitudinal direction of the meandering heat generating resistor 4 shown in FIG. 1, and this heat generation length is appropriately selected depending on the intended use.

  In addition, in FIG. 2, although the boundary line is drawn between the ceramic core material 2 and the ceramic sheet | seat 3, in fact, after an unbaked ceramic molded object and a ceramic green sheet are bonded together, by baking, In many cases, the boundary as the bonding surface is eliminated.

In Reference Embodiment 1, it is preferable to form a primary plating layer after firing on the electrode pad 7 of the ceramic heater 1. This primary plating layer is for improving the brazing strength and improving the flow of the brazing material when the lead member 8 is brazed to the surface of the electrode pad 7. Since the primary plating layer has a thickness of 1 to 5 [mu] m, the adhesion is enhanced, which is preferable. As a material of the primary plating layer, Ni, Cr, or a composite material containing these as a main component is preferable, and plating mainly including Ni having excellent heat resistance is more preferable.

  Further, when used in an atmosphere with high humidity, it is preferable to use an Au-based or Cu-based brazing material because migration is less likely to occur. As the brazing material, Au, Cu, Au—Cu, Au—Ni, Ag, and Ag—Cu are preferable because of their high heat resistance. In particular, Au—Cu brazing, Au—Ni brazing, and Cu brazing are more preferable because of their high durability. In order to improve the high temperature durability and protect the brazing material from corrosion, it is preferable to form a secondary plating layer usually made of Ni on the surface of the brazing material.

  Further, as the material of the lead member 8, since the temperature of the lead member 8 rises during use due to heat transfer from the heating resistor 4, a Ni-based or Fe-Ni-based alloy having good heat resistance is used. It is preferable.

The feature of the reference embodiment 1 is that in the ceramic heater 1 in which the conductor pattern is built, the conductor pattern has a folded portion constituting the heating resistor 4 and is adjacent to the folded portion. The void occupancy ratio of the ceramic body between the conductors is 0.01 to 50%. In addition, the void occupancy ratio of the ceramic body between any conductors adjacent at the folded portion is more preferably 0.1 to 40%, and further preferably 1 to 20%. When the void occupancy is less than 0.01%, when rapid heating and rapid cooling are repeated, when the heating resistor 4 that is a heating part is heated and expanded, the heat of the ceramic body around the heating resistor 4 is increased. since dissipation is insufficient, the thermal expansion of the ceramic body does not follow the thermal expansion of the heating resistor 4, stress concentrates to the edge 41 of the heating resistor, crack or break or generated There is a fear. On the other hand, if the void occupancy is larger than 50%, when continuous energization is performed at a high temperature, the insulation performance of the ceramic body around the heating resistor 4 serving as the heating portion tends to deteriorate and the durability performance tends to decrease. Note that if the ceramic green sheet is stuck to the ceramic molded body as it is and fired in close contact, the numerical value becomes larger than the void occupancy in the above range. Therefore, in order to obtain the void ratio in the above range, a manufacturing method described later is employed.

FIG. 2 is a cross-sectional view (cross-sectional view taken along the line XX shown in FIG. 1) showing an example of a cross section perpendicular to the longitudinal direction, and the conductor in the folded portion of the conductor pattern (heating resistor 4) is the ceramic core 2 The state arrange | positioned in the outer periphery circular shape is shown. Here, the void occupancy ratio of the ceramic body between the conductors is 0.01 to 50%, as shown in FIG. 3, the voids of the ceramic body between any adjacent conductor patterns (4a and 4b in FIG. 3). It means that the occupation ratio when measured is 0.01 to 50%. The portion where the void occupancy of the ceramic body is 0.01 to 50% may be any portion of the cross section that cuts the heating resistor 4 perpendicular to the longitudinal direction. In addition, between the conductors, when the ceramic body is cylindrical, as shown in FIG. 3, the upper side of the adjacent conductor pattern 4a and the upper side of 4b are connected to the outer circumference circle of the ceramic core material 2 (in other words, the ceramic body A line connected along the outer surface), a line connecting the lower side of the conductor 4a and the lower side of 4b along the outer circumference of the ceramic core 2, and a region A surrounded by the surfaces of the conductors 4a and 4b. Say. When the ceramic body is flat, as shown in FIG. 4, a line connecting the upper side of the adjacent conductor 4c and the upper side of the conductor 4d, a line connecting the lower side of the conductor 4c and the lower side of the conductor 4d, This refers to the region B surrounded by the surfaces of the conductors 4c and 4d.
In this specification, when the ceramic body is cylindrical, an annular region sandwiched between the outer periphery of the ceramic core 2 and the outer periphery separated from the outer periphery by the thickness of the conductor along the outer periphery, In the case of a flat plate shape, an inner region sandwiched between a line connected so as to be in contact with the upper side of each conductor and a line connected so as to be in contact with the lower side of each conductor is referred to as a conductor forming region. That is, between the conductors defined as described above refers to a portion located between adjacent conductors in the conductor forming region.

Furthermore, in the ceramic heater of Reference Embodiment 1, it is preferable that the length along the outer surface of the void existing between adjacent conductors is equal to or less than ½ of the conductor interval. In other words, in the folded portion of the conductor pattern, on any line connecting adjacent conductors along the outer surface, the length of the line (distance between conductors) exceeding ½ in the ceramic body between the conductors It is preferable that no void exists. If the length of the void exceeds 1/2 of the distance between the conductors, the insulation of the ceramic body surrounded by the heating resistor 4 that is the heating part deteriorates when continuous energization is performed at a high temperature. Deteriorates. For example, in the case of the cylindrical ceramic heater shown in FIG. 3, the arbitrary line refers to an arbitrary line that connects the adjacent conductors 4a and 4b in the region A along the outer surface. The arbitrary line in this case is an arcuate curve having substantially the same center as the center of the circle formed by the outline (outer surface of the ceramic body) of the sectional view of the cylindrical ceramic heater shown in FIG. In the case of the flat ceramic heater shown in FIG. 4, it means an arbitrary straight line connecting the adjacent conductors 4 c and 4 d in the region B.

Furthermore, it is preferable that the thickness of the conductors constituting the conductor pattern, in particular a heating resistor 4 is 5 to 100 [mu] m. If the thickness of the conductor pattern is less than 5 μm, voids between any adjacent conductors can be prevented, but in the high-temperature continuous durability and high-temperature cycle durability test, it causes resistance change and disconnection of the heating resistor 4 that is a heating part, Durability performance deteriorates. On the other hand, when the thickness of the conductor pattern exceeds 100 μm, it tends to be difficult to suppress the void ratio between adjacent arbitrary conductors to 50% or less.

Next, the manufacturing method of the ceramic heater of the present invention for setting the void occupancy ratio of the ceramic body between arbitrary adjacent conductors to 0.01 to 50% will be described.

  As an example, a conductor pattern is formed on the surface of the first ceramic green sheet, and on the surface of the first ceramic green sheet on which the conductor pattern is formed, at least substantially the same thickness as the conductor pattern, preferably the same thickness. It is possible to employ a method of laminating a second ceramic green sheet that is more flexible than the ceramic green sheet. According to this method, voids between patterns can be eliminated by filling the gap corresponding to the thickness of the conductor pattern with the flexible second ceramic green sheet. Here, the second ceramic green sheet needs to be more flexible than the first ceramic green sheet, and if the second ceramic green sheet is flexible, the first ceramic green sheet provided with the conductor pattern is more flexible. This is because when the second ceramic green sheets are bonded together, both ceramic green sheets are brought into close contact with each other at least in the central portion between the conductors. Here, the hardness of this ceramic green sheet is measured with a digital indicator (manufactured by Mitutoyo Corporation), and the depth of penetration of a φ1 mm needle in 30 seconds is preferably 200 μm or more. This is because if the hardness of the ceramic green sheet, that is, the penetration depth is less than 200 μm, voids are formed because the conductors do not come into close contact with each other. In addition, in order to reduce the space | gap between patterns, you may apply pressure using a press.

Another reference manufacturing method may be a screen printing method of paste. This method is performed as follows. First, the heating resistor 4 and the lead extraction part 5 are formed on the ceramic green sheet by screen printing. At this time, the paste applied by screen printing is an organic resin binder composed mainly of a powder having a high melting point metal (W, Mo, Re, etc.) and an adhesive component, mainly ethyl cellulose, nitrocellulose and a diluent. The organic solvent used, mainly T.I. P. O (terpineol), D.I. B. P (dibutyl phthalate), D.I. O. P (dioctyl phthalate), B.I. C. It is a product obtained by mixing A (butyl carbitol acetate) or the like. These pastes are printed in a raw thickness range of 5 to 150 μm. Further, the conductor pattern is formed by adjusting the line width, the print thickness, the specific resistance of the paste, or the like so that the resistance value of the heating resistor 4 is about 10 times the resistance value of the lead extraction portion 5. Next, in order to fill a gap corresponding to the thickness between adjacent conductors, a paste containing an insulator is applied by screen printing. The paste used at this time is an insulator having a high melting point and mainly has the same composition as the ceramic green sheet, that is, 88 to 95% by weight of Al ₂ O ₃ , ₂ to 7% by weight of SiO ₂ , and 0.5% of CaO. 3 wt%, the MgO 0.5 to 3% by weight, a binder in an organic resin consisting of an adhesive component in alumina ceramics composed of ZrO ₂ from 1 to 3 wt%, mainly used ethyl cellulose, as nitrocellulose and diluent Organic solvents, mainly T.P. P. O (terpineol), D.I. B. P (dibutyl phthalate), D.I. O. P (dioctyl phthalate), B.I. C. It is a product obtained by mixing A (butyl carbitol acetate) or the like. Furthermore, as the paste, in addition to the ceramic green sheet composition, an alumina single component or a paste having an insulating property with a volume resistivity of 10 ⁸ Ω or more can be used. Here, the viscosity of the paste is desirably adjusted in the range of 50 dPa · s to 1000 dPa · s for printing. When the viscosity of the paste is 50 dPa · s or less, the printability is excellent, but the green density is low. Therefore, the amount of drying shrinkage increases, and a step is formed on the upper side of the conductor pattern, and voids are easily generated after firing. A viscosity of 1000 dPa · s or more is not preferable because leveling properties are lowered, and voids and the like are easily generated in the coating. Note that the screen printing is performed by a screen in which the heating resistor and the lead extraction portion are reversed.

Further, as another manufacturing method as a reference, a filling method using a dispenser can also be adopted. As described above, when the paste viscosity is 1000 dPa · s or more, the green density can be set high, and the amount of shrinkage due to drying shrinkage can be reduced as much as possible, so the gap between the conductors is ensured. Although it can be filled, the method by screen printing is not preferred and cannot be adopted. Therefore, when using such a high-viscosity paste, a filling method using a dispenser can be preferably employed.

  Thus, the method using screen printing or a dispenser is an effective method in that an insulator can be filled between conductors instead of on a conductor pattern.

Although discloses a ceramic body formed by firing a ceramic green sheet is wound around a ceramic molded body forms 1, a cylindrical reference, flat plate-shaped ceramic molded body or a conductor such as a ceramic green sheet A ceramic body obtained by laminating and firing a printed ceramic green sheet may also be used .

Reference form 2.
Next, the heating device 51 of Reference Embodiment 2 will be described.

FIG. 5 is a partially cutaway side view showing a configuration example of the hair iron 100 using the heating device 51 according to the second embodiment . In FIG. 5, 50 is a gripping member, 52 is a shaft that couples the pair of gripping members 50 so that they can be opened and closed, and 53 is mounted in a bearing portion 54 so that the tip ends of both gripping members are always in the opening direction. The coil spring is energized. Reference numeral 55 denotes a plate-like body 55 that is fitted to and faces each of the openings 56 provided at the front ends of both gripping members 50, and 57 denotes a heater plate that is in close contact with the back surface of the plate-like body 55.

  6 is a front view showing the positional relationship between the heater plate 57 and the plate-like body 55 taken out from the heating device 51 of FIG. 5, and FIG. 7 is a sectional view taken along the line XX. Heat of the heater plate 57 is transmitted to one main surface 55b of the plate-like body 55 via one main surface 57a of the heater plate 57, and uniformly heats the heating surface 55a which is the other main surface of the plate-like body 55. Can do.

  With such a configuration, the plate-like body 55 having the wide heating surface 55a can be efficiently and uniformly heated using the small ceramic heater plate 57.

  The hair iron of FIG. 5 can hold the gripping member 50 with a finger and sandwich the hair with the plate-like body 5 to heat the hair uniformly.

That is, the heating device 51 of the reference form 2 includes a heater plate 57 in which a resistance heating element 58 is embedded in a plate-like ceramic body, and a plate-like body 55 having a heating surface 55a for heating an object to be heated. This is a heating device 51 in which one main surface 55 b of the shaped body 55 comes into contact with one main surface 57 a of the heater plate 57. The upper SL heating surface 55a consists chamfered portion of the C-plane or a curved surface provided on and around the flat portion, the thickness H of the heater plate 57 is characterized in that it is a 0.5 to 5 mm. In the heater plate 57, a resistance heating element 58 is embedded in a plate-shaped ceramic body. The resistance heating element 58 is shielded from the atmosphere, and the resistance heating element 58 is prevented from being corroded by moisture contained in the atmosphere. can do. Further, the resistance heating element 58 embedded in the plate-shaped ceramic body generates Joule heat at a predetermined temperature when a certain electric power is applied due to its own electric resistance, and the heater plate 57 is required as a heating element. The temperature can be raised to a predetermined temperature.

  The heating surface 55a includes a flat portion and a chamfered portion with a C surface or a curved surface provided around the flat portion, so that the object to be heated is damaged even if the object to be heated is inserted while sliding on the heating surface 55a. There is little possibility to give. As described above, when the object to be heated is hair, in order to make it difficult to damage the hair, when the chamfered portion is a C surface, the size Wc is preferably 0.1 to 5 mm, more preferably. Is 0.3 to 4 mm. More preferably, it is 1-3 mm. In addition, when the chamfered portion is a curved surface, the curved surface is formed by an arc or a quadratic curve in a cross section perpendicular to the end surface, and if the width Wr is 0.2 to 5 mm, the object to be heated is damaged. This is preferable in reducing the amount of the ink. More preferably, it is 0.3-4 mm, More preferably, it is 1-3 mm.

  Further, when the thickness H of the heater plate 57 is 0.5 to 5.0 mm, the heat of the heater plate 57 can be efficiently transmitted to the plate-like body 55. If the thickness of the heater plate 57 is less than 0.5 mm, the flatness of one main surface of the plate-like body 55 is as large as 0.02 to 0.2 mm, so that stress is applied when the heater plate 57 is mounted, and the heater The plate 57 may be damaged.

  Further, if the thickness of the heater plate 57 exceeds 5 mm, even if the heater plate 57 is attached to the plate-like body 55, one main surface 57a of the heater plate 57 is not deformed, and one main surface of the heater plate 57 is not deformed. This is because 57a and one main surface 55b of the plate-like body 55 cannot be in wide contact with each other, and the heating surface 55a of the plate-like body 55 cannot be heated uniformly.

  Therefore, if the thickness of the heater plate 5 is 0.5 to 5 mm, one main surface 57a of the heater plate 57 and one main surface 55b of the plate-like body 55 are deformed in accordance with each, so that the heating surface 55a is widened. It can be heated to a uniform temperature. More preferably, the thickness of the heater plate 55 is 1 to 3 mm.

  Further, it is desirable to provide a heat transfer member 63 between one main surface 55 b of the plate-like body 55 and one main surface 57 a of the heater plate 57. When the heat transfer member 63 is present, heat transfer between the one main surface 57a of the heater plate 57 having the surface roughness Ra and the one main surface 55b of the plate-like body 55 becomes easier, and the heat of the heater plate 57 is reduced. This is preferable because it can be efficiently transmitted to the plate-like body 55.

  It is desirable that the heat transfer member 63 be a silicon resin or a resin mixed with a metal fine powder having a high thermal conductivity. Gold, silver, copper, and nickel are preferable as the metal fine particle powder because of their high thermal conductivity, and more preferably silver. As the resin, silicon resin or fluororesin can be used. Further, the heat transfer member can eliminate a gap between one main surface 55 a of the plate-like body 55 and one main surface 57 a of the heater plate 57, and the thermal expansion between the plate-like body 55 and the heater plate 57. Even if expansion / contraction deviation due to the difference occurs, it is preferable that the heat transfer member 63 can prevent the temperature difference of the heating surface 55a from increasing without changing the heat conduction between the main surface 55a and the main surface 57a.

The pressurized thermal device 51 preferably has a surface roughness Ra of the one main surface 57a of the heater plate 57 is 1 to 30. If the surface roughness Ra of one main surface 57a of the heater plate 57 is less than 1.0, it is difficult to transmit heat uniformly through the contact surface with the plate-like body 55, and the surface 55a to be heated This is because the in-plane temperature difference may increase. On the other hand, if the surface roughness Ra exceeds 30, the surface roughness becomes so large that the substantial contact area with the plate-like body 55 becomes small and the plate-like body 55 may not be heated uniformly. is there. More preferably, the surface roughness Ra of one main surface of the heater plate 57 is 3-10.

  5 and 6, the heater plate 57 is pressed against the heater plate 57 by the claw 55c of the plate-like body 55 (FIG. 7), but the heater plate 57 is directly pressed by the claw 55c. Instead, as shown in FIG. 8, the heater plate 57 is pressed by the spring 59 fixed to the claw, and the one main surface 55b of the holding plate-like body 55 and the one main surface 57a of the heater plate 57 are elastically pressed to contact each other. It can also be made. Setting a plurality of pressing portions of the spring 59 is preferable because the heater plate 57 and the main surface of the plate-like body 55 can be brought into contact in a wide range. And it is preferable to comprise the spring 59 with the leaf | plate spring provided with the some fulcrum.

The plate- like ceramic body is preferably a ceramic mainly composed of alumina, mullite, or silicon nitride. The ceramic is preferable because of its relatively high thermal conductivity, excellent corrosion resistance, and high insulation resistance at high temperatures.

Moreover, when a plate-shaped ceramic body is an alumina, it is desirable that the alumina content is 80-98 mass%. This is because the thermal conductivity of the plate-like ceramic body is as large as 16.7 to 25.21 W / (m · K), the high temperature insulation resistance at 300 ° C. is as large as 10 ¹³ Ω · cm or more, and the bending strength is 300 MPa or more. This is because it becomes larger. This is because if the alumina content is less than 80% by mass, sintering aids and impurities such as Mn, Ca, Si and the like increase and insulation resistance at high temperatures may be lowered.

  On the other hand, if the alumina content exceeds 99.5% by mass, it becomes difficult to sinter densely at a relatively low temperature of 1700 ° C. or less because of a small amount of sintering aid, making it difficult to mass-produce at low cost. is there.

The plate- like body 5 is desirably a conductive metal. This is because the metal has a large thermal conductivity of 200 W / (m · K) or more, and can uniformly transfer the heat of the heater plate 7 to the heating surface 55a. As said metal, aluminum, iron, and these alloys are preferable. The thermal expansion coefficient of the plate-like body 5 made of metal is desirably 8 to 25 × 10 ⁻⁶ / ° C. or less, but in particular 8 to 17 × 10 ⁻⁶ / ° C. close to the thermal expansion coefficient of the plate-like ceramic body 57. A range of is desirable. Because of the difference in thermal expansion between the plate-like body 55 and the heater plate 57, the distance between the main surface 57a and the main surface 55b becomes non-uniform so that heat conduction cannot be performed uniformly, and the uniformity of temperature distribution may be impaired. It is. Further, the object to be heated is brought into contact with the heating surface 55a, and heat is transferred from the heating surface 55a to the object to be heated. At this time, the object to be heated and the heating surface 5a slide while in contact with each other. There is a possibility that static electricity may be generated. However, it is preferable that the heating surface 55a has conductivity because this static electricity can be released.

  Moreover, it is desirable that the area of the contact surface where the plate-like body 55 and the heater plate 57 are in contact is 20 to 80% of the area of the heating surface 55a. This is because if it is less than 20%, the heating surface 55a of the plate-like body 55 may not be heated uniformly. Moreover, when the area of the contact surface where the plate-like body 55 and the heater plate 57 are in contact exceeds 80% of the area of the heating surface 55a, the heater plate 57 becomes large, and the price of the heating device 51 becomes expensive and industrially used. It is because there exists a possibility that it may become difficult. More preferably, the area of the contact surface is 30 to 60% of the area of the heating surface 55a.

  The thickness B of the plate-like body 55 is preferably 0.2 to 10 mm. If this is smaller than 0.2 mm, when the plate spring 59 is fixed to the heater plate 57 by the plate spring 59, the plate-like body 55 is deformed and a gap is generated, or a defect such as a piece contact occurs. This is because the in-plane temperature difference may increase. Further, if the thickness of the plate-like body 55 exceeds 10 mm, the heat capacity becomes large, and even if the heater plate 57 is heated, the temperature of the heating surface 55a of the plate-like body 55 may not rise quickly. The thickness B is more preferably 1 to 3 mm.

  The thickness of the heater plate 57 is a distance between the main surface 55b and the main surface 55a and can be represented by an average value of three points.

  Such a plate-like body 55 is preferably made of a metal having a thermal conductivity of 200 W / (m · K) or more, but is provided with a claw 55 c at its peripheral portion so as to come into surface contact with the heater plate 57, It is preferable to increase the thickness of the substrate to increase the heat capacity to reduce the temperature difference on the heating surface.

Next, the production method and other configurations of the pressure heat system 51.

The heater plate 57 is made of a heat-resistant ceramic such as an aluminum oxide sintered body, a mullite sintered body, or a silicon nitride sintered body. For example, when the heater plate 57 is made of an aluminum oxide sintered body, aluminum oxide (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO), magnesia (MgO), etc., an appropriate organic solvent and solvent are added and mixed to form a slurry, which is then formed by a conventionally known doctor blade method or calendar roll method. To form a ceramic green sheet. Next, the ceramic green sheet is appropriately punched.

  The resistance heating element 58 is made of a metal material such as tungsten or molybdenum. A resistance heating element paste obtained by adding and mixing an appropriate organic solvent or solvent to the metal powder such as tungsten is mixed into a ceramic green sheet serving as a plate-like ceramic body. The resistance heating element 8 can be embedded in the plate-shaped ceramic body by printing and applying in a predetermined pattern in advance by a conventionally known screen printing method. The raw heater plate embedded with the resistance heating element 58 is fired at a high temperature (about 1600 ° C.), whereby the heater plate 7 can be produced. At this time, in order to obtain the surface roughness, it is preferable to adjust the firing temperature and time so that the crystal size of the surface of the heater plate 57 is 0.5 to 5 μm.

  Both ends of the resistance heating element 58 are led out to the end portions of the heater plate 57, and both ends led to the end portions are exposed through openings A provided in the plate-like body 57, and the lead wires 61 are brazing materials such as solder. It is attached by brazing. The opening A that exposes both ends of the resistance heating element 58 functions to form a region where the resistance heating element 58 and the lead wire 61 are brazed, and is previously punched into a ceramic green sheet that becomes a plate-like ceramic body. Is formed at the end of the heater plate 57. The opening A is further provided with a recess 62 having a size corresponding to the diameter of the lead wire 61 on the side wall thereof. When the resistance heating element 58 and the lead wire 61 are brazed in the opening A, the side wall of the opening A is formed. If the lead wire 61 is inserted into the recessed portion 62 formed in the upper portion, the lead wire 61 can be accurately aligned with the central portion of the upper surface of the resistance heating element 58 to expose the lead wire 61. It becomes possible to braze and attach very firmly via the.

  The lead wire 61 brazed to the resistance heating element 58 in the opening A is made of a metal such as nickel, and the lead wire 61 connects the resistance heating element 58 to an external electric circuit and the resistance heating element from the external electric circuit. 58 is supplied with a constant electric power required to generate Joule heat at a predetermined temperature.

  The lead wire 61 is accurately brought into contact with the central portion of the exposed upper surface of the resistance heating element 58 using the recess 62 provided on the side wall of the opening A, and a solder material 61 such as solder is supplied to the contact portion. Thus, the resistance heating element 58 is firmly brazed and attached.

Thus, according to the heating device 51 of this supply constant power to the resistance heating element 58 via the lead wire 61 functions as a heat generator by Joule heating of the resistance heating element 58 at a constant temperature.

Incidentally, although attaching the lead wire 61 through the brazing material such as solder resistance heating element 58 which is exposed in the first of the above mentioned references, it can be filled with a resin, glass or the like into the opening A the attachment Alternatively, the opening A may be filled with a heat-resistant material and covered with an insulating plate. In this case, the resistance heating element 58 and the lead wire 61 are more firmly attached, which is preferable. In the above-described example , the lead wire 61 is attached to the resistance heating element 58 via a brazing material such as solder. It may be attached by filling and maintaining glass or the like.

  The heating device 51 is brought into contact with the metal plate 55 through silicon grease or the like. At this time, the thickness of the buffer material which is also the heat transfer member 63 of the plate 55 and the ceramic heater plate 57 is 5 to 5. It is desirable that the thickness is 100 μm. This is because the ceramic heater plate 57 and the plate-like body 57 are in contact with each other, so that when the ceramic heater plate 57 and the metal heater plate 57 are brought into direct contact with each other, the ceramic ceramic heater plate 57 and the metal plate are made of porcelain. There is a possibility that the joint surface does not come into uniform contact due to warpage with the body 55 or deformation due to thermal expansion during heating, and the contact surface comes into contact with each other, causing heat conduction in a spot and increasing the temperature difference of the heating surface 55a. . The thickness of the cushioning material, which is the heat transfer member 63, may be as small as necessary, but conversely, if it is too thick, there may be a problem that the heat conduction between the ceramic heater and the metal plate deteriorates. The thickness is preferably 1 to 100 μm.

In hair iron using heating apparatus of the second or reference, the heater plate 57 is provided with a conductor pattern having a folded portion constituting the heat generation resistor 4, any adjacent conductors at its folded portion It is preferable that the void occupancy ratio of the ceramic body in between is 0.01 to 50% (for example, a heater plate made of a plate-like ceramic heater shown in FIG. 4 of Embodiment 1 is used). If it does in this way, since durability of heater board 57 can be made high, a hair iron with higher durability can be provided. In addition, the void occupancy ratio of the ceramic body between any conductors adjacent at the folded portion is more preferably 0.1 to 40%, and further preferably 1 to 20%.

<Reference Example 1>
A ceramic green sheet containing Al ₂ O ₃ as a main component and adjusting SiO ₂ , CaO, MgO, and ZrO ₂ to be within 10% by weight in total is prepared. From this surface, a W (tungsten) powder binder and a solvent are prepared. The heating resistor 4 and the lead extraction part 5 were printed using the paste.
An electrode pad 7 was printed on the back surface. The heating resistor 4 was produced so as to have a pattern of four reciprocations with a heat generation length of 5 mm.
And in order to fill an insulator between conductors, the paste containing the insulator was performed by screen printing. At this time, in order to change the void occupancy ratio of the ceramic body between the conductors, an object not subjected to screen printing, and an object subjected to screen printing by changing the viscosity of the paste were prepared.
Then, a through hole 6 was formed at the end of the lead lead portion 5 made of W, and conduction between the electrode pad 7 and the lead lead portion 5 was achieved by injecting a paste therein. The position of the through hole 6 was formed so as to enter the inside of the brazing portion when brazing was performed.
The ceramic green sheet thus prepared was brought into close contact with the periphery of the ceramic molded body and fired at 1600 ° C. to obtain a ceramic heater 1.

各サンプルの材質は、いずれもアルミナであり、＊印を付したサンプルは、本発明の範囲外のものである。 With respect to the ceramic heater 1 thus obtained, durability was evaluated by measuring a resistance change after continuous energization at 1200 ° C. for 100 hours. Each lot n = 10 was evaluated.
Moreover, the thing whose resistance value changed 15% or more with respect to the initial resistance value was counted as a disconnection.
Moreover, about each sample of each lot n = 3, the cross section of the heating resistor 4 after baking was observed by SEM, and the void ratio was measured. These results are shown in Table 1.
(Table 1)

The material of each sample is alumina, and samples marked with * are outside the scope of the present invention.

As can be seen from Table 1, in Sample No. 9 in which the void occupancy ratio of the ceramic body between the conductors exceeds 50%, and in Sample No. 1 with a void occupancy ratio of 0.005%, a disconnection in which the resistance value changes by 15% or more occurred. . On the other hand, the sample with a void occupancy ratio of 50% or less did not cause disconnection and exhibited good durability.
Further, if the void occupancy was within the range of the invention, the durability performance was not significant even if the other factors such as the void length and ink thickness were changed.

<Reference Example 2>
First, in order to obtain a ceramic heater plate as shown in FIG. 9, a ceramic sheet having Al ₂ O ₃ as a main component and adjusted so that SiO ₂ , CaO, MgO, and ZrO ₂ are within 10 wt% in total. , W resistance heating elements were printed. The opening A that exposes both ends of the resistance heating element functions to form a region where the resistance heating element and the lead wire are brazed, and the ceramic green sheet serving as the heater plate is previously punched by a punching method. It is formed at the end of the heater plate. The opening A is further formed with a recess having a size corresponding to the diameter of the lead wire on the side wall thereof, and the lead portion of the resistance heating element and the lead wire are brazed in the opening A. Next, after forming a coat layer composed of substantially the same components as the ceramic sheet on the surface of the resistance heating element and sufficiently drying, an adhesive solution in which ceramics having substantially the same composition as the ceramic sheet is further applied is applied, The ceramic sheets thus prepared were laminated and adhered, and fired at 1500 to 1600 ° C.

  Further, after forming a 3 μm-thick plating layer made of Ni on the surface of the lead portion of the resistance heating element, a lead wire 61 mainly composed of Ni is formed at 1030 ° C. in a reducing atmosphere using a brazing material 62 made of Ag. To obtain a heater plate.

  The heater plate and plate-like body obtained by the above method were combined to produce a hair iron in which the thickness of the heater plate, surface roughness (Ra), presence / absence of spring pressing, presence / absence of heat transfer member and material were changed.

  And the temperature distribution of the surface of the heating surface of the produced hair iron is measured with a temperature distribution measuring device manufactured by JEOL (TG-6200), and the maximum temperature and the minimum temperature of the surface of the heating surface are calculated to calculate the maximum temperature. The temperature difference was measured as the temperature variation.

板状体厚み１．５ｍｍ、板状体・ヒータ板接触面積と加熱面面積比率７０%にて評価した。
また、※印は本発明の範囲外であることを示す。 The results are shown in Table 2.
(Table 2)

Evaluation was made with a plate-like body thickness of 1.5 mm, a plate-like / heater plate contact area and a heating surface area ratio of 70%.
Moreover, * mark shows that it is outside the scope of the present invention.

  As can be seen from Table 2, sample no. Samples having a heater plate thickness of 0.5 to 5 mm, such as 3 to 15, exhibited excellent characteristics with a small temperature variation of 19 ° C. or less on the heating surface.

  In contrast, sample no. In Nos. 1 and 2, the heater plate was as small as 0.3 mm, and the heater plate was damaged when the heater plate was loaded on the plate-like body. In addition, samples having a heater plate thickness of 7 mm as in sample Nos. 16 and 17 were not preferable because the temperature variation on the heating surface was 22 ° C. or higher.

  Further, Sample No. provided with a heat transfer member between the plate-like body and the heater plate. It was found that 5 to 13 were preferable because the temperature variation on the heating surface was 16 ° C. or less, and the temperature variation was further small.

  In addition, sample No. 1 having a surface roughness of the main surface of the heater plate of 1 to 30 μm. 6 to 11 were found to be more preferable because the temperature variation of the heating surface was as small as 15 ° C. or less.

Sample No. 1 in which one main surface of the plate-like body and one main surface of the heater plate were pressed with a spring. 7 to 9, it was found that the temperature variation of the heating surface was 13 ° C. or less, and the temperature variation was improved.

<Reference Example 3>
Next, the content of Al ₂ O ₃ as the main component of the heater plate was adjusted between 70% and 99.8% to prepare ceramic sheets, and these were used to prepare heater plates by the method described in Reference Example 2 . . The high-temperature insulation strength and bending strength at 200 ° C. were measured using materials having different composition amounts of Al ₂ O ₃ . The bending strength was measured according to a JIS standard 4-point bending strength test by preparing 20 test pieces, and the average value was shown.
(Table 3)

As can be seen from Table 3, Sample No. with an alumina content of 80 to 99.5%. Nos. 23 to 25 have a high-temperature insulation resistance of 1 × 10 ¹³ Ω · cm or more, and even when used as a hair iron, it has been found that there is no leakage from the heater heating power source, which is more preferable. Further, it has been found that the bending strength is as large as 300 MPa or more, and it is preferable that the resistance heating element is less likely to be damaged by thermal stress even if it is repeatedly heated rapidly.

However, sample no. When the alumina content is as small as 70 and 75% by mass as in Nos. 21 and 22, the insulation resistance at high temperature is as small as 10 ¹¹ Ω · cm or less, and there is a risk of leakage through the heater plate. Sample No. No. 26 had a large alumina content of 99.8% by mass and had to be sintered at a firing temperature of 1700 ° C. or higher, and it was difficult to mass-produce at low cost.

  More preferably, sample no. It was found that when the alumina content was 90 to 99.5% as in 24 and 25, the bending strength was large and preferable.

  The alumina content was determined by ICP quantitative analysis of the produced plate-like ceramic body.

<Reference Example 4>
Next, a hair iron in which the outer shape of the plate-like body is fixed to 4 mm × 80 mm × 20 mm (thickness × length × width) and the length of the heater plate is sequentially changed to change the contact area and the heating area ratio is referred to as Reference Example 2 . It produced similarly.

  Then, a rated voltage is applied to the resistance heating element in a state in which a silicon-based resin is provided as a heat transfer member between the heater plate and the plate-like member and pressed by a spring, and the highest temperature portion of the heating surface is brought to a saturation temperature of 200 ° C. from room temperature. The time until this was measured as the heating surface saturation time.

The results are shown in Table 4.
(Table 4)

  From Table 4, the sample No. with an area ratio of 20 to 80% was obtained. It was found that Nos. 33 to 42 exhibited excellent characteristics with a small heating surface saturation time of 60 seconds or less.

  Sample No. with an area ratio of 30 to 60% was used. It was found that Nos. 34 to 41 had a small heating surface saturation time of 57 seconds or less and exhibited further excellent characteristics.

  On the other hand, Sample No. in which the contact area ratio between the heater plate 7 and the plate-like body 5 and the heating surface contact area ratio is less than 20%. Nos. 31 and 32 were not preferable because the saturation time was 63 seconds or more.

  Sample No. When the contact area exceeds 80% as in 43, the heater plate becomes too large, the cost of the heater plate becomes expensive, and the industrial utility value is low.

  Furthermore, sample No. whose thickness of a plate-shaped object is 0.2-10 mm. It was found that 36 to 39 are preferable because the heating surface saturation time is as small as 50 seconds or less.

Claims (1)

Forming a conductive paste in a predetermined pattern on the surface of the first ceramic green sheet;
The surface of the first ceramic green sheet on which the conductive paste is formed has at least the same thickness as the conductive pattern, is more flexible than the first ceramic green sheet, and has a diameter of 1 mm when measured with a digital indicator. A step of producing a ceramic green sheet laminate by laminating a second ceramic green sheet having a hardness of 200 μm or more with which the needle penetrates in 30 seconds;
Winding the ceramic green sheet laminate around a cylindrical ceramic molded body and bonding together;
A method for producing a ceramic heater, comprising a step of firing the laminated ceramic green sheet laminate and the ceramic molded body.

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