JP5825813B2 - heater - Google Patents

Description

  The present invention relates to a heater used for an ignition heater for various combustion devices such as an ignition heater and an oil fan heater in a combustion-type in-vehicle heating device, a heating heater for a measurement device, and the like.

  2. Description of the Related Art Heating heaters for various combustion engines that use gas, kerosene, and the like and heaters for various heating devices are formed by embedding a refractory metal resistor in an insulating base such as ceramics. Usually, these heaters are molded and fired by laminating or press-molding ceramic green sheets, and thus have a relatively simple shape such as a plate shape, a prismatic shape, or a cylindrical shape (for example, see Patent Document 1). reference).

JP-A-2-242020

  In various combustion devices using a gas such as natural gas or propane gas, the ignition temperature of the gas is as high as 1100 ° C. or higher. Even when a ceramic with high heat resistance is used, the deterioration of the structure progresses over time, the durability becomes insufficient and the life is shortened. Therefore, it is necessary to lower the ignition temperature.

  An object of the present invention is to provide a heater that can reliably ignite a fuel such as gas even when the temperature of the ceramic heater at the time of fuel ignition is set to a relatively low temperature, thereby improving durability and having a long life. It is.

The heater of the present invention includes an insulating base and a resistor embedded in the insulating base, and is provided along the longitudinal direction in the entire longitudinal direction of the exposed region of the side surface of the insulating base. and a heater, wherein a plurality of irregularities formed of impact ridges are provided.

  Moreover, the heater of this invention is a heater characterized by the above-mentioned structure, wherein the said protrusion part is curvilinear.

  Moreover, the heater of this invention is a heater characterized by having a notch in a part of said protrusion part in said structure.

  Moreover, the heater of this invention is a heater characterized by providing the said unevenness | corrugation in a pair of side surface which opposes in said structure.

The heater of the present invention, in the above configuration, the shape of the irregularities is a heater, characterized in that different between the pair of side surfaces against direction.

  According to the heater of the present invention, when the heater is arranged so that the main surface is perpendicular to the gas flow and the side surfaces are parallel, the gas flow passing near the side surface of the heater is disturbed, and the back surface of the heater Until the gas flows in, the contact time between the gas and the heater becomes longer. Therefore, the heater temperature can be set low, and the life of the heater can be extended.

  In addition, the resistance against the gas is increased, and the generated turbulent flow makes it easier for the gas and air to mix and ignite, thereby reducing the amount of gas used.

(A) is a perspective view which shows an example of embodiment of the heater of this invention, (b) is an internal perspective view of the heater shown to (a). (A) is the sectional view on the AA line shown to Fig.1 (a), (b) is a schematic perspective view which shows the principal part of the heater shown to (a). (A) is a side view which shows the other example of embodiment of the heater of this invention, (b) is a schematic perspective view which shows the principal part of the heater shown to (a). (A) is a side view which shows the other example of embodiment of the heater of this invention, (b) is a schematic perspective view which shows the principal part of the heater shown to (a). It is a side view which shows the other example of embodiment of the heater of this invention. It is sectional drawing which shows the other example of embodiment of the heater of this invention. It is sectional drawing which shows the other example of embodiment of the heater of this invention.

  Hereinafter, an example of an embodiment of a heater of the present invention will be described in detail with reference to the drawings.

  FIG. 1A is a perspective view showing an example of an embodiment of the heater of the present invention, and FIG. 1B is an internal perspective view of the heater shown in FIG. 2A is a cross-sectional view taken along line AA shown in FIG. 1A, and FIG. 2B is a schematic perspective view showing a main part of the heater shown in FIG.

  A heater 1 according to the present embodiment shown in FIGS. 1 and 2 includes an insulating base 2 and a resistor 3 embedded in the insulating base 2, and unevenness 7 is provided on the side surface of the insulating base 2. .

  The insulating substrate 2 is made of ceramics having insulating properties such as oxide ceramics, nitride ceramics, carbide ceramics, for example, alumina ceramics, silicon nitride ceramics, aluminum nitride ceramics, silicon carbide ceramics, etc. Can do. From the viewpoint of heat resistance, it is preferable to use silicon nitride.

  Examples of the shape of the insulating base 2 include a rectangular plate shape, a prismatic shape, and a columnar shape. In the case of the rectangular plate shape as shown in FIG. 1, for example, the width is 4 to 50 mm, the thickness is 1 to 20 mm, and the length. The thing of the dimension of 30-100 mm is employ | adopted.

  A resistor 3 is embedded in the insulating base 2. The resistor 3 has a folded shape in the longitudinal section, and a heat generating portion 31 that generates most heat near the center of the folded shape (near the middle point of the folded) located at the tip when energized. The resistor 3 is embedded at the front end side of the insulating base 2, and the distance from the front end of the resistor 3 (near the center of the folded shape) to the rear end of the resistor 3 is, for example, 2 to 10 mm. The cross-sectional shape of the resistor 3 may be any shape such as a circle, an ellipse, or a rectangle, and is usually formed so that the cross-sectional area is smaller than a lead 4 described later.

  The material for forming the resistor 3 is preferably a material mainly composed of a refractory metal such as W, Mo, or Re that can be produced by simultaneous firing with the insulating substrate 3. In order to make the thermal expansion coefficient of the resistor 3 close to the thermal expansion coefficient of the insulating base 2 and relieve the stress due to the difference in the thermal expansion coefficient when the heater 1 is heated and lowered, the components of the insulating base 2 It may be included.

  A pair of leads 4 and a pair of extraction electrodes 5 are embedded in the insulating base 2. In the device shown in FIG. 1, leads 4 are respectively joined to both end portions (one end portion and the other end portion) of a resistor 3 having a folded shape from one end to the other end. Each lead 4 is electrically connected to the resistor 3 on one end side and electrically connected to the extraction electrode 5 on the other end side. The lead electrode 5 is electrically connected to the lead 4 at one end side and led to the surface of the insulating base 2 at the other end side.

  The lead 4 and the extraction electrode 5 are formed of the same material as that of the resistor 3. For example, the lead 4 and the extraction electrode 5 have a larger cross-sectional area than the resistor 3 or less content of the forming material of the insulating base 2 than the resistor 3. As a result, the resistance value per unit length is lowered.

  As shown in FIG. 1A, the surface of the insulating base 2 is a metal having a coefficient of thermal expansion close to that of the insulating base 2 so as to be electrically connected to the derived extraction electrode 5, for example, Fe—Ni—Co. An electrode fitting 6 made of an alloy and a soft metal such as Ni is attached and connected to an external circuit (not shown) via the electrode fitting 6. The electrode fitting 6 is usually attached to the end of the insulating base 2, and the pattern of the extraction electrode 5, the lead 4 and the resistor 3 is determined so as to be electrically connected to the electrode fitting 6.

  As shown in FIGS. 1A and 2, the side surface of the insulating base 2 is provided with unevenness 7. Various shapes can be mentioned as the shape of the unevenness 7, but the unevenness 7 in the examples shown in FIG. 1A and FIG. 2 is a shape composed of a plurality of protrusions 71 provided along the length direction of the side surface. It is. The shape formed by the plurality of protrusions 71 in the example shown in FIG. 1A and FIG. 2 is, in other words, the shape formed by the plurality of grooves 72. The width of the protrusion 71 and the width of the groove 72 are, for example, 10 to 300 μm, and the height of the protrusion 71 and the depth of the groove 72 are, for example, 10 to 300 μm. And the width | variety and height of each protrusion part 71 and the width | variety and depth of each groove | channel 72 may be the same, or may differ.

  Normally, the heater 1 is arranged so that the main surface (surface having a large area) of the insulating base 2 is perpendicular to the gas flow (arrow shown in FIG. 2A) as shown in FIG. The side surface having a small area is arranged to be parallel to the gas flow. As shown in FIG. 2, the unevenness 7 is provided on the side surface, so that when the heater 1 is arranged so that the main surface is perpendicular to the gas flow and the side surface is parallel, the heater 1 The flow of the gas passing near the side of the gas is disturbed, the gas flows to the back surface of the heater 1, and the contact time between the gas and the heater 1 becomes long. Therefore, the temperature of the heater 1 can be set low, and the life of the heater 1 can be extended. In addition, the resistance against the gas is increased, and the generated turbulent flow makes it easier for the gas and air to mix and ignite, thereby reducing the amount of gas used.

  Here, as shown in FIG. 3, the protrusion 71 may be curved. Since the protrusion 71 has a curved shape, the flow rate of the gas passing through the vicinity of the side surface of the heater 1 can be different, the gas flow is more disturbed, the gas and air are mixed more easily, and the gas is easily ignited. The amount used can be reduced. The curved shape is not limited to a shape in which clean curves are formed side by side, and a curved shape or a straight line may be disturbed. And as shown in FIG.3 (b), the protrusion 71 does not need to be continuous from one end to the other end in the length direction of the side surface. The effect like 73 is also acquired.

  Moreover, as shown in FIG. 4, you may have the notch 73 in a part of protrusion part 71. As shown in FIG. By having the notch 73 in a part of the protrusion 71, the gas passing through the notch 73 hits the protrusion 71, and a part of the gas flows along the protrusion 71 in the length direction. Therefore, the gas is agitated and easily ignited, and the amount of gas used can be reduced. The width of the notch 73 is preferably, for example, 10 to 500 μm from the viewpoint of gas stirrability. Further, as shown in FIG. 4B, the notch 73 may have the same depth as the height of the protrusion 71 formed by cutting out a part of the protrusion 71. The depth may be shallower than the height of the protrusion 71. Furthermore, the shape of the notch 73 seen in a cross section includes a quadrangle, a triangle, a semicircle, and the like, and is not particularly limited.

  Moreover, as shown in FIG. 5, the shape which consists of several dents 74 in which the unevenness | corrugation 7 is scattered may be sufficient. Due to the shape of the plurality of recesses 74 in which the unevenness 7 is scattered, a gas flow vortex is generated in the vicinity of the recesses 74 and the force of the gas to vibrate the heater 1 is reduced, and the heater 1 is less likely to vibrate. Therefore, the generation of noise can be suppressed. From the viewpoint of vibration suppression, the diameter when the opening of the recess 74 is circular is preferably 50 μm to 1 mm, for example, and the depth of the recess 74 is preferably 10 to 200 μm.

  1 and 2 show a configuration in which the unevenness 7 is provided on one of the opposing side surfaces of the insulating base 2, the present invention is not limited to this configuration, and as shown in FIG. May be provided on a pair of side surfaces facing each other. FIG. 6 shows a cross section of another example when the heater is cut along the line AA shown in FIG. By providing the unevenness 7 on both of the pair of side surfaces facing each other, the gas and air are more easily mixed and ignited, and the amount of gas used can be further reduced.

  In addition, as shown in FIG. 7, it is preferable that the shape of the unevenness 7 is different between a pair of side surfaces facing each other, so that the flow of gas passing near each side surface can be made different, and further the air And gas are mixed, making it easier to ignite and reducing the amount of gas used. FIG. 7 shows a cross section of another example when the heater is cut along the line AA shown in FIG.

  As an example in which the shape of the concavo-convex 7 is different between a pair of opposing side surfaces, when the concavo-convex 7 is the ridge 71, the width, height, or number of the ridge 71 (the width and depth of the groove 72). Or the number of the notches 73 may be different from each other, or the formation position, shape (width, depth), or number of the notches 73 may be different. Moreover, when the unevenness | corrugation 7 is the recess 74, although the magnitude | size, depth, or number of the recess 74 is mentioned, there is no limitation in particular.

  The unevenness 7 may be provided not only on the side surface in the longitudinal direction but also on the side surface in the short direction.

  Next, the manufacturing method of the heater of this Embodiment is demonstrated.

First, in order to produce an insulating substrate made of such ceramics, sintering aids such as SiO ₂ , CaO, MgO, ZrO ₂ are added to ceramic components such as alumina ceramics, silicon nitride ceramics, aluminum nitride ceramics, and silicon carbide ceramics. To prepare a powder.

  A compact is produced from the powder by press molding. Alternatively, the powder is prepared into a ceramic slurry and formed into a sheet shape to produce a ceramic green sheet.

Then, on one main surface of the molded body or the ceramic green sheet, a method such as screen printing is applied to the pattern of the conductive paste to be the resistor 3, the conductive paste to be the lead 4, and the conductive paste to be the lead electrode 5, respectively. Use to form. At this time, by changing the length and line width of the conductive paste to be the resistor 3 and the conductive paste to be the lead 4 and the distance and interval of the folded pattern of the resistor 3 in accordance with the use of the heater. The heat generation position and resistance value of the resistor 3 are set to desired values. The conductive paste to be the resistor 3 and the conductive paste to be the lead 4 are mainly composed of a refractory metal such as W, Mo, Re or the like that can be produced by simultaneous firing with the insulating substrate 2. A material prepared by mixing and kneading the above-mentioned ceramic, binder, organic solvent or the like with a melting point metal can be used.

  By superimposing a molded body of the same material on the molded body on which the pattern of the conductive paste is formed, a molded body serving as an insulating base having the resistor 3 and the lead 4 inside is obtained.

  In the case of a ceramic green sheet instead of a molded body, a ceramic green sheet of the same material is laminated on the ceramic green sheet on which the pattern of the conductive paste is formed, and is adhered to each other using an adhesion liquid. A ceramic green sheet molded body serving as an insulating substrate having the body 3 and the lead 4 is obtained.

  Next, a plurality of obtained molded bodies are arranged, and a partition plate coated with a release material for preventing adhesion is inserted between adjacent molded bodies (around the molded bodies). Here, the pattern shape of the unevenness 7 is formed on at least a part of the surface of the partition plate. Thus, when the molded body is baked and the molded body is baked and contracted, the surface shape of the partition plate is transferred to the molded body to obtain a desired uneven shape. Here, various uneven shapes can be obtained by changing the shape of the partition plate.

  Next, a heater can be manufactured by baking the obtained molded object at the temperature of 1500-1800 degreeC under the pressure of 30 MPa-50 MPa, for example. Firing is preferably performed in an inert gas atmosphere or a reducing atmosphere, and is preferably performed in a state where pressure is applied.

  In addition, the method for forming the unevenness on the side surface is not limited to the method of inserting and baking the partition plate, and may be a method of roughening by polishing or the like, for example.

  Finally, the electrode fitting 6 is attached to the obtained sintered body. Specifically, the electrode fitting 6 is attached to the end of the insulating base 2 so as to be electrically connected to the extraction electrode 5 led to the surface of the insulating base 2.

  By the above method, the heater of the present invention is obtained.

  The heater of the Example of this invention was produced as follows.

First, MoSi whose main component is Si ₃ N ₄ and whose thermal expansion coefficient is close to the oxide and resistor of rare earth oxide elements such as ytterbium (Yb), yttrium (Y), erbium (Er) as a sintering aid. A ceramic raw material powder to which a ceramic conductor such as ₂ or WC was added was prepared.

  And the said powder was shape | molded by press molding, and the molded object was obtained.

Next, using a conductive paste for resistors prepared by mixing WC, which is a high melting point metal, ceramic raw material powder, a binder, an organic solvent, etc., a resistor pattern is formed on the molded body using a technique such as screen printing. Formed. Similarly, a lead pattern was formed on the molded body by using a method such as screen printing using a conductive paste for leads. Furthermore, the pattern of the extraction electrode was formed on the molded body using a method such as screen printing using the conductive paste for the extraction electrode.

  A molded body of the same material is further superimposed on the molded body on which the pattern of the conductive paste is formed, and a partition plate coated with a release material for preventing adhesion is inserted around the obtained molded body, under a reducing atmosphere, Hot press firing was performed at 1700 ° C. and a pressure of 35 MPa.

  Here, partition plates having various shapes were prepared, and heaters (Sample 1 to Sample 8) having different irregularities were produced. Each sample was fired simultaneously under the same conditions. Each sample has a thickness of 1.3 mm, a width of 4.7 mm, and a length of 40 mm, and only the side shape is different.

  Specifically, the sample 1 was provided with a protrusion having a width of 100 μm, a height of 20 μm, and a length of 100 to 1000 μm on one side in a random direction on one side surface (1.3 mm × 40 mm).

  In Sample 2, eight protrusions having a width of 100 μm and a height of 20 μm were provided on one side surface (1.3 mm × 40 mm) along the length direction.

  In Sample 3, eight curved ridges having a width of 100 μm and a height of 20 μm were provided on one side surface (1.3 mm × 40 mm) along the length direction.

  Sample 4 is provided with eight protrusions with a width of 100 μm and a height of 20 μm along one length on one side (1.3 mm × 40 mm), and the protrusion has a notch with a width of 20 μm and a depth of 20 μm. Were provided at 100 to 400 locations per one ridge.

  In Sample 5, one side of the side surface (1.3 mm × 40 mm) was provided with point-like dents having a diameter of 100 μm to 400 μm and a height of 100 to 200 μm on the entire side surface with an interval of 50 to 200 μm.

  Sample 6 was provided with eight protrusions with a width of 100 μm and a height of 20 μm along the length direction on both side surfaces (1.3 mm × 40 mm).

  Sample 7 is provided with eight protrusions having a width of 100 μm and a height of 20 μm on one side surface (1.3 mm × 40 mm) along the length direction, and the other side surface (1.3 mm × 40 mm) has a width of 300 μm. Three kamaboko-shaped grooves having a height of 50 μm were provided.

  Further, a conventional heater having a flat side surface was prepared as a sample 8 for comparative evaluation.

  Among the prepared heaters, the durability test was performed on the heaters of Sample 1 and Sample 8.

  Specifically, after setting the sample in the gas heater and checking the temperature at which the heater ignites, it is energized for 30 seconds at the ignited temperature, and then repeatedly turned on and off in a cycle where the energization is stopped for 60 seconds. The test was conducted.

  As a result, in Sample 1, the endurance life (number of cycles) was about 280,000 cycles, whereas in Sample 8, the endurance life (number of cycles) was about 50,000 cycles.

That is, the heater (sample 1) of the present invention has a durability life of 3 compared to the conventional heater (sample 8).
It turned out to be 6 times.

  Next, the ignition time of the heaters of Sample 1 to Sample 8 was measured.

  Specifically, the heaters of Samples 1 to 8 were set in the gas heater, the heater set temperature was set to 1200 ° C., and the time until the gas was ignited was examined. The number of measurements is 10 times, and the average value is shown.

  As a result, the ignition time of sample 1 is about 17 seconds, the ignition time of sample 2 is about 16 seconds, the ignition time of sample 3 is about 15 seconds, the ignition time of sample 4 is about 13 seconds, and the ignition time of sample 5 is about The ignition time of sample 6 was about 13 seconds, the ignition time of sample 7 was about 12 seconds, and the ignition time of sample 8 was about 25 seconds.

  That is, it was found that the ignition time is shortened by providing the side surface with unevenness.

  Further, for the heaters of Sample 5 and Sample 8, the sound volume generated when the heater contacts the gas was measured.

  Specifically, 0.2 MPa of air was sprayed onto the heaters of Sample 5 and Sample 8, and the magnitude of the generated sound was examined.

  As a result, the sample 5 was about 67 dB while the sample 5 was about 52 dB. In general, a desirable sound level is said to be 0 to 60 dB, and it has been found that generation of noise can be suppressed by a plurality of scattered dents.

1: Heater 2: Insulating substrate 3: Resistor 4: Lead 5: Lead electrode 6: Electrode fitting 7: Concavity and convexity 71: Projection 72: Groove 73: Notch 74: Recess

Claims (5)

An insulating substrate, and a inside buried resistor of the insulating substrate, provided along the longitudinal direction across the longitudinal direction of the exposed region of the side surfaces of the insulating substrate, the butt strip portion A heater having a plurality of projections and depressions.   The heater according to claim 1, wherein the protrusion is curved.   The heater according to claim 1, wherein a part of the protruding portion has a notch.   The heater according to claim 1, wherein the unevenness is provided on a pair of opposing side surfaces.   The heater according to claim 1, wherein the uneven shape is different between a pair of opposing side surfaces.

Images