JP6829022B2 - heater - Google Patents

Description

The present disclosure relates to a heater used for a fluid heating heater, a powder heating heater, a gas heating heater, an oxygen sensor heater, a soldering iron heater, and the like.

A rod-shaped or tubular ceramic body, a heat-generating resistor provided inside the ceramic body, and an electrode portion connected to the heat-generating resistor and exposed at the rear end of the ceramic body are joined to the electrode portion. A heater provided with a lead terminal is known (see, for example, Patent Document 1).

In the above heater, an electrode portion is provided on the surface of the rear end portion of a rod-shaped or tubular core material, and a ceramic green sheet on which a heat generating resistor pattern is printed is provided on the surface of the core material provided with the electrode portion. It was produced by wrapping it so that it was exposed and firing it.

JP 2015-197949

Here, since the electrode portion provided on the surface of the core material has a curved surface, there is a problem that it is difficult to align the lead terminal when joining the electrode portion and it is difficult to accurately join the lead terminal to a desired position. there were.

If the lead terminals are not accurately joined at the desired positions, stress will be applied to the joint between the lead terminals and the electrodes when the heater is attached to the device due to slight dimensional deviations, and long-term use will occur. There was a risk of damage to this joint.

The present disclosure has been made in view of the above circumstances, and it is possible to improve the accuracy of alignment when joining the lead terminal to the electrode portion, and it is possible to suppress damage to the joint portion between the lead terminal and the electrode portion. The purpose is to provide a heater.

The heater of the present disclosure is a rod-shaped or tubular ceramic body having a recess on the outer peripheral surface, a heat generating resistor provided inside the ceramic body, and a heat generating resistor provided on the bottom surface of the recess of the ceramic body. It includes an electrode portion connected to a resistor and a lead terminal joined to the electrode portion, and the lead terminal has a first portion rising from the electrode portion and a length direction of the ceramic body. It is provided with an extended second portion, the first portion rising along the side wall of the recess, and having a gap between the joining material for joining the first portion and the electrode portion and the side wall. It is characterized by doing.

According to the heater of the present disclosure, the accuracy of alignment when joining the lead terminal to the electrode portion can be improved. As a result, damage to the joint portion between the lead terminal and the electrode portion can be suppressed even after long-term use.

(A) is a schematic perspective view of an example of the embodiment of the heater, and (b) is a view seen in the direction of the arrow of the heater shown in (a). It is sectional drawing cut along the ii-ii line shown in FIG. 1 (b). (A) is a schematic perspective view of another example of the heater embodiment, and (b) is a view seen in the direction of the arrow of the heater shown in (a). (A) is a schematic perspective view of another example of the heater embodiment, and (b) is a view seen in the direction of the arrow of the heater shown in (a). (A) is a schematic perspective view of another example of the heater embodiment, and (b) is a view seen in the direction of the arrow of the heater shown in (a). (A) is a schematic perspective view of another example of the heater embodiment, and (b) is a view seen in the direction of the arrow of the heater shown in (a). (A) to (c) are schematic plan views of other examples of the heater embodiment.

Hereinafter, embodiments of the heater will be described with reference to the drawings.

FIG. 1A is a schematic perspective view of an example of an embodiment of a heater, and FIG. 1B is a view seen in the direction of the arrow of the heater shown in FIG. 1A. Further, FIG. 2 is a cross-sectional view taken along the line ii-ii shown in FIG. 1 (b).

The heater 1 shown in FIGS. 1 and 2 has a ceramic body 2 which is rod-shaped or tubular and has a recess on the outer peripheral surface, a heat generating resistor 3 provided inside the ceramic body 2, and a recess 21 of the ceramic body 2. The electrode portion 4 provided on the bottom surface of the ceramic and connected to the heat generating resistor 3 and the lead terminal 5 joined to the electrode portion 4 are provided, and the lead terminal 5 has a first portion 51 rising from the electrode portion 4. A second portion 52 extending along the length direction of the ceramic body 2 is provided, and the first portion 51 rises along the side wall of the recess 21.

The heater 1 of the present embodiment can be heated by passing a fluid object to be heated such as a liquid, a gas, and a powder around the ceramic body 2, for example. The ceramic body 2 in the heater 1 is a rod-shaped or tubular member having a length direction. Examples of the rod shape include a columnar shape and a prismatic shape. The rod shape referred to here also includes, for example, a plate shape elongated in a specific direction. Further, as the tubular shape, for example, a cylindrical shape or a square tubular shape can be mentioned. In the heater 1 shown in FIG. 1, the ceramic body 2 has a cylindrical shape.

When the ceramic body 2 has a tubular shape (cylindrical shape), the heater 1 is used so as to bring the object to be heated into contact with the inner peripheral surface or the outer peripheral surface of the ceramic body 2 to heat the ceramic body 2. Although not shown, when the ceramic body 2 has a rod shape, the heater 1 is used so as to bring the object to be heated into contact with the outer peripheral surface of the ceramic body 2 to heat the ceramic body 2.

The ceramic body 2 is made of an insulating ceramic material. Examples of the insulating ceramic material include alumina, silicon nitride or aluminum nitride. It is preferable to use aluminum nitride in terms of excellent thermal conductivity. On the other hand, it is preferable to use alumina because it has oxidation resistance and is easy to manufacture.

When the ceramic body 2 has a cylindrical shape, the dimensions can be set, for example, to have a total length of 40 to 150 mm in the length direction, an outer diameter of 4 to 30 mm, and an inner diameter of 1 to 28 mm. When the ceramic body is cylindrical, the dimensions can be set, for example, to have a total length of 40 to 150 mm in the length direction and an outer diameter of 4 to 30 mm.

The ceramic body 2 has a recess 21 on the outer peripheral surface. As will be described later, the recess 21 exposes the electrode portion 4 provided inside the ceramic body 2 so that the lead terminal 5 can be joined to the electrode portion 4 inside the recess 21. is there.

A heat generating resistor 3 is provided inside the ceramic body 2. In other words, the heat generating resistor 3 is embedded in the ceramic body 2. The heat generation resistor 3 heats the ceramic body 2 by generating heat when an electric current flows. One end of the heat generating resistor 3 is electrically connected to one of the pair of drawer electrodes 9 described later, and the other end is electrically connected to the other of the pair of drawer electrodes 9 described later. Although not shown, the heat generating resistor 3 has a folded-back portion (serpentine portion) provided along the circumferential direction while being repeatedly folded back in the length direction.

The heat generation resistor 3 is made of a conductor mainly composed of a metal having a high melting point such as tungsten (W), molybdenum (Mo) or rhenium (Re). The dimensions of the heat generating resistor 3 can be set, for example, to have a width of 0.3 to 2 mm, a thickness of 0.01 to 0.1 mm, and a total length of 500 to 5000 mm. These dimensions are appropriately set according to the heat generation temperature of the heat generation resistor 3, the voltage applied to the heat generation resistor 3, and the like.

An electrode portion 4 connected to the heat generating resistor 3 is provided on the bottom surface of the recess 21 of the ceramic body 2. The electrode portion 4 is for electrically connecting an external power source and the heat generating resistor 3. The electrode portions 4 are provided at two locations on the rear end side of the ceramic body 2, and the lead terminals 5 are joined to each other and connected to an external power source via the lead terminals 5.

The electrode portion 4 is made of a metal material such as tungsten or molybdenum, and may be the same metal material as the heat generating resistor 3 or may be a different metal material. The dimensions of the electrode portion 4 can be set, for example, to have a length of 9 mm, a width of 5 mm, and a thickness of 0.02 mm.

The lead terminal 5 has a first portion 51 rising from the electrode portion 4 and a second portion 52 extending along the length direction of the ceramic body 2, and the first portion 51 and the second portion 52 are It is connected via a bend. As the lead terminal 5, for example, a wire rod or a plate material made of nickel or copper metal can be used. Examples of the cross-sectional shape of the lead terminal 5 include a circular shape, an elliptical shape, a rectangular shape, and an annular shape. When the lead terminal 5 has a circular cross section, the diameter is, for example, 0.5 to 2.0 mm.

The joining material 6 joins the first portion 51 of the lead terminal 5 rising from the electrode portion 4 and the electrode portion 4, and extends on the electrode portion 4 centering on the first portion 51. As the bonding material 6, for example, a brazing material such as silver brazing or silver copper brazing material can be used.

The length of the first portion 51 constituting the lead terminal 5 is set to, for example, 1.0 mm to 3.0 mm. Further, the rising direction of the first portion 51 may be inclined at 20 ° or less when viewed from the surface of the electrode portion 4 in a vertical direction and a vertical direction. The tilting direction may be any of the length direction of the ceramic body 2, the circumferential direction of the ceramic body 2, and the combined direction of these. In particular, when the first portion 51 rises in a direction perpendicular to the surface of the electrode portion 4, the bonding material 6 can be easily spread evenly around the first portion 51. Therefore, the lead terminal 5 can be firmly held with a small amount of bonding material 6.

The width of the recess 21 (width along the circumferential direction of the ceramic body 2) is, for example, 1 to 6 mm. The depth of the recess 21 (distance along the radial direction of the ceramic body 2) is, for example, 0.1 to 1.5 mm.

Then, the first portion 51 of the lead terminal 5 rises along the side wall of the recess 21. Here, the fact that the lead terminal 5 rises along the side wall of the recess 21 means that the lead terminal 5 is in direct contact with the side wall of the recess 21, or that the first portion 51 of the lead terminal 5 and the recess 21 are in contact with each other. It means that the bonding material 6 is inserted between them.

With this configuration, the lead terminal 5 can be joined to the electrode portion 4 while the first portion 51 of the lead terminal 5 is supported along the side wall of the recess 21, so that the lead terminal 5 can be joined to the electrode portion 4 as desired. Can be joined accurately to the position of. Further, an electrode portion is provided on the surface of the rear end portion of the rod-shaped or tubular core material, and a ceramic green sheet on which a heat generating resistor pattern is printed is wound around the surface of the core material so that the electrode portion is exposed. In the heater 1 of the present embodiment, the heat generating resistor 3 can be arranged in the region other than the recess 21, so that the heat equalizing property of the heater 1 can be improved and the rear end portion of the core material is not exposed. Therefore, the heater 1 can be miniaturized.

Further, as shown in FIG. 3, the recess 21 may be configured to be open to the end surface and the outer peripheral surface of the ceramic body 2. Here, the configuration in which the recess 21 is open to the end face and the outer peripheral surface of the ceramic body 2 is a configuration in which the recess 21 is open toward the end face of the ceramic body 2, in other words, the ceramic body. It is a configuration in which a part of the outer surface side in the thickness direction of No. 2 is cut out from the end face. Further, the end face of the ceramic body 2 referred to here is an end face on the rear end side of the ceramic body 2 in the length direction.

According to this configuration, the degree of freedom of the method of joining the lead terminal 5 to the electrode portion 4 is increased by sliding the lead terminal 5, and the open space is increased from the joint portion between the lead terminal 5 and the electrode portion 4. It is possible to improve the heat dissipation property of the lead terminal 5 and the durability of the joint portion between the lead terminal 5 and the electrode portion 4.

As shown in FIG. 4, the portion (core material) on the inner surface side in the thickness direction of the ceramic body 2 may have a shape protruding toward the rear end side.

Further, as shown in FIG. 5, the recess 21 may have a slit shape and extend from one end face of the ceramic body 2 toward the other end face. The one end face of the ceramic body 2 referred to here is the end face on the rear end side in the length direction, and the other end face of the ceramic body 2 is the end face on the front end side in the length direction.

The recess 21 extends in the length direction of the ceramic body 2 and has a narrow slit shape in the direction along the circumferential direction of the ceramic body 2, so that the heat equalizing property in the length direction and the circumferential direction of the heater 1 is formed. Is improved. Further, since the recess 21 has a narrow slit shape, it is easier to fix the lead terminal 5 when it is joined to the electrode portion 4, and the accuracy of the fixing position can be further improved.

When the recess 21 has a slit shape, the width (width along the circumferential direction of the ceramic body 2) is, for example, 0.5 to 4 mm.

The heater 1 shown in FIG. 5 has a slit-shaped recess 21 opened on the rear end surface of the ceramic body 2, but does not open on the rear end surface of the ceramic body 2. It may be.

Further, as shown in FIG. 6, the recess 21 may be configured to be open to one end surface (end surface on the rear end side), the outer peripheral surface and the other end surface (end surface on the front end side) of the ceramic body 2. .. Here, the configuration in which the recess 21 is open to one end face, the outer peripheral surface, and the other end face of the ceramic body 2 means that the recess 21 extends from one end face of the ceramic body 2 to the other end face. In other words, it is a configuration in which a part of the ceramic body 2 on the outer surface side in the thickness direction is cut out from one end to the other end.

This configuration also increases the degree of freedom in the method of joining the lead terminal 5 to the electrode portion 4, increases the open space, improves the heat dissipation from the joint portion between the lead terminal 5 and the electrode portion 4, and leads. The durability of the joint portion between the terminal 5 and the electrode portion 4 can be improved. Further, the heat equalizing property in the length direction and the circumferential direction of the heater 1 can be improved. Further, it is easy to fix the lead terminal 5 at the time of joining to the electrode portion 4, and the accuracy of the fixing position can be improved.

Further, as shown in FIG. 7, the shape of the corner portion of the concave portion 21 may be arcuate when viewed in a plan view. Note that FIG. 7A shows the shape of the corner of the recess 21 shown in FIG. 1 in an arc shape, and FIG. 7B shows the shape of the corner of the recess 21 in FIG. 7A being further rounded. As a whole, the shape is substantially circular, and FIG. 7 (c) shows the shape of the corner of the recess 21 shown in FIG. 3 in an arc shape. As a result, it is possible to prevent cracks from occurring in the corners of the recess 21.

In the heater 1 shown in FIGS. 1 to 7, the recess 21 faces the center of the ceramic body 2 when the joint portion of the lead terminal 5 to the electrode portion 4 is viewed in a cross section perpendicular to the longitudinal direction of the ceramic body 2. There is one place for each position. In this way, since the recesses 21 face each other, the distance between the recesses 21 is the longest, so that the thermal stress when the thermal cycle is applied to the ceramic body 2 is dispersed, and the recess 21 due to the thermal stress is the starting point. It is possible to prevent cracks.

Next, an example of the method for manufacturing the heater of the present embodiment will be described. In this example, an example in which the ceramic body 2 is made of cylindrical alumina ceramics will be described.

First, an alumina ceramic green sheet containing Al ₂ O ₃ as a main component and adjusted so that SiO ₂ , CaO, MgO, and ZrO ₂ are within 10% by mass in total is produced.

In addition, the above components are mixed to produce a rod-shaped or tubular molded body by press molding, extrusion molding, or the like.

As the material of the heat generating resistor pattern or the electrode portion pattern, a material containing a refractory metal such as W, Mo, Re, which can be produced by simultaneous firing with the ceramic body 2, as a main component is used. At this time, the heat generation position and resistance of the heat generation resistor 3 are changed by changing the length of the pattern of the resistor paste to be the heat generation resistor 3, the distance / interval of the folded pattern, and the line width of the pattern according to the application of the heater. Set the value to the desired value.

Next, a transfer film such as a PET film using a resistor paste that serves as a heat generating resistor 3 and an electrode portion pattern that serves as an electrode portion 4 are printed on different PET films by screen printing or the like. Print. The PET film on which the heat generation resistor pattern is printed is wound so as to be pressed against the side surface of the rod-shaped or tubular molded body, and the transfer is performed. Next, the PET film on which the electrode pattern is printed is transferred to the molded product in the same manner. A sheet was formed on the molded body to which these patterns were transferred. The ceramic green sheet was provided with holes or notches to be recesses using a mold or the like, and laminated so that the electrode pattern was exposed using an adhesive liquid. By doing so, the electrode portion pattern is exposed, and a rod-shaped or tubular molded body that becomes a ceramic body 2 having a heat generating resistor pattern inside can be obtained.

Next, the obtained rod-shaped or tubular molded product is fired at about 1500 ° C. to 1600 ° C. in a non-oxidizing gas atmosphere such as hydrogen gas. Further, a brazing material such as Au, AuCu, AgCu, or Ag wax is used as the bonding material 6 to bond the electrode portion 4 and the lead terminal 5 made of Ni. The lead terminal 5 may be connected as a Ni wire rod, or the insulating tube may be provided on the Ni wire after connecting the Ni wire to the electrode. When joining the lead terminal 5 using the joining material 6, a brazing material processed into a thin sheet is wound in advance around the outer circumference of the first portion 51 of the lead terminal 5 in contact with the electrode portion 4, and the brazing material is used. It is better to heat and melt.

By the above method, the heater 1 of the present embodiment can be manufactured.

1: Heater 2: Ceramic body 21: Recessed part 3: Heat generation resistor 4: Electrode part 5: Lead terminal 51: First part 52: Second part 6: Bonding material

Claims (5)

A ceramic body that is rod-shaped or tubular and has a recess on the outer peripheral surface, a heat-generating resistor provided inside the ceramic body, and a heat-generating resistor provided on the bottom surface of the recess of the ceramic body and connected to the heat-generating resistor. An electrode portion and a lead terminal joined to the electrode portion are provided, and the lead terminal includes a first portion rising from the electrode portion and a second portion extending along the length direction of the ceramic body. The first portion rises along the side wall of the recess, and there is a gap between the joining material that joins the first portion and the electrode portion and the side wall. Heater. The heater according to claim 1, wherein the recess is open to an end surface and an outer peripheral surface of the ceramic body. The heater according to claim 2, wherein the recess is slit-shaped and extends from one end face of the ceramic body toward the other end face. The heater according to claim 2 or 3, wherein the recess is open to one end face, an outer peripheral surface, and the other end face of the ceramic body. The heater according to any one of claims 1 to 3, wherein the shape of the corner portion of the concave portion is arcuate when viewed in a plan view.