Electric heating carrier

Abstract

To provide an electric heating carrier capable of intending longevity of a flame spray fixed layer, by suppressing deviation of long life of a flame spray fixed layer.SOLUTION: An electric heating carrier according to the present invention includes a pair of metal electrodes 2 for applying a voltage to the honeycomb structure connected to the electrode layer 11. Each of the pair of metal electrodes 2 has a base 20 and a comb-shaped connecting portion 21 with a plurality of teeth 22. The plurality of teeth 22 include proximal connecting teeth 220p, 221p connected to the electrode layer 11 at a first position, and distal connecting teeth 220d, 221d connected to the electrode layer 11 at a second position. The electrodes are formed such that the difference in current flowing through each of the plurality of teeth 22 is reduced compared to the case where the electrical resistance of each of the plurality of proximal connecting teeth 220p, 221p is equal to each other and the electrical resistance of each of the plurality of distal connecting teeth 220d, 221d is equal to each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electrically heated carrier. [Background technology]

[0002] Electrically heated catalysts (EHCs) are generally known in which electrodes are disposed on a honeycomb structure made of conductive ceramics, and the honeycomb structure itself is heated by passing current through it, thereby raising the temperature of the catalyst supported on the honeycomb structure to an activation temperature before starting the engine, thereby purifying exhaust gas emitted immediately after starting the internal combustion engine. To efficiently purify exhaust gas by heating the honeycomb structure through current passing, it is necessary to heat the honeycomb structure while maintaining a uniform temperature distribution within the honeycomb structure. To achieve this, it is necessary to pass current through the honeycomb structure as uniformly as possible, which requires a strong connection between the honeycomb structure and the electrodes. Patent Document 1 listed below discloses joining comb-shaped metal electrodes to an electrode layer (surface electrode) provided on the honeycomb structure by thermal spraying. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-058864 Summary of the Invention [Problem to be solved by the invention]

[0004] When a comb-shaped metal electrode is joined to an electrode layer of a honeycomb structure by thermal spraying as in Patent Document 1, the current flowing through each tooth tends to vary depending on the position of each tooth constituting the comb tooth and the connection position between each tooth and the electrode layer. When electricity is repeatedly passed through the metal electrode, the resistance of the sprayed fixing layer of the tooth through which more current flows increases more quickly and the tooth no longer conducts electricity (reaching the end of its life), and as a result, the current of the other tooth parts increases, shortening the life of the sprayed fixing layer of the other tooth parts.

[0005] The present invention has been made to solve the above-mentioned problems, and one of its objects is to provide an electrically heated carrier that can suppress bias in the life of the sprayed fixed layer and extend the life of the sprayed fixed layer. [Means for solving the problem]

[0006] Item 1. In one embodiment, the present invention provides a honeycomb structure including: a honeycomb structure portion having an outer peripheral wall; partition walls disposed inside the outer peripheral wall and defining a plurality of cells that form flow paths extending from one end face to the other end face; and a pair of electrode layers provided on the surface of the outer peripheral wall; and a pair of metal electrodes connected to the electrode layers for applying a voltage to the honeycomb structure, each of the pair of metal electrodes having a base and a comb-like connecting portion having a plurality of teeth extending from the base, the plurality of teeth having a tooth body and a connecting portion for connecting each of the tooth bodies to the electrode layer. and a plurality of sprayed fixing layers connecting the plurality of teeth to the electrode layer, wherein the plurality of teeth have a plurality of proximal connection teeth connected to the electrode layer at a first position in the extension direction of the teeth, and a plurality of distal connection teeth connected to the electrode layer at a second position farther from the base than the first position in the extension direction of the teeth, and the plurality of teeth are formed so that the difference in current flowing through each of the plurality of teeth is smaller than when the electrical resistances of each of the plurality of proximal connection teeth are equal to each other and the electrical resistances of each of the plurality of distal connection teeth are equal to each other.

[0007] Item 2. The present invention may relate to an electrically heated carrier according to Item 1, wherein the plurality of teeth include a plurality of end teeth arranged at both ends of the comb teeth in the extension direction of the base, and a plurality of intermediate teeth arranged between the end teeth, and the electrical resistance of the end teeth is higher than the electrical resistance of the intermediate teeth.

[0008] Item 3. The present invention may relate to an electrically heated carrier according to Item 2, wherein the plurality of end teeth include an end proximal connecting tooth connected to the electrode layer at a first position in the extension direction of the teeth and an end distal connecting tooth connected to the electrode layer at a second position in the extension direction of the teeth, the plurality of intermediate teeth include an intermediate proximal connecting tooth connected to the electrode layer at a first position in the extension direction of the teeth and an intermediate distal connecting tooth connected to the electrode layer at a second position in the extension direction of the teeth, the end proximal connecting tooth is disposed inside the end distal connecting tooth in the extension direction of the base, and at least one of the intermediate proximal connecting tooth is disposed inside the intermediate distal connecting tooth in the extension direction of the base, and the electrical resistance increases in the order of the end proximal connecting tooth, the end distal connecting tooth, the intermediate proximal connecting tooth, and the intermediate distal connecting tooth.

[0009] Item 4. The present invention may relate to the electrically heated carrier according to any one of Items 1 to 3, wherein the plurality of teeth are formed so that the electrical resistances thereof differ from one another depending on the width of the tooth body.

[0010] Item 5. The present invention may relate to an electrically heated carrier according to any one of Items 1 to 4, wherein the plurality of teeth are formed so that their electrical resistances differ from one another depending on the thickness of an additional member added to the tooth body, the presence or absence of the additional member, or the thickness of the tooth body itself.

[0011] Item 6. The present invention may relate to an electrically heated carrier according to any one of Items 1 to 5, wherein the plurality of teeth are formed so that their electrical resistances differ from one another due to the material of the tooth body itself or the material of an additional member added to the tooth body.

[0012] Item 7. The present invention may relate to an electrically heated carrier according to any one of claims 1 to 6, wherein the tooth portions are formed so that their electrical resistances are different from one another by bending the tooth portion body in the thickness direction to form an accordion shape, or by serpentining the tooth portion body in the extension direction of the base, thereby changing the current path lengths from the base to the sprayed fixing layer.

[0013] Item 8. The present invention may relate to the electrically heated carrier according to any one of Items 1 to 7, wherein the plurality of teeth are formed so as to have different electrical resistances from one another depending on the material of the thermal sprayed fixing layer.

[0014] Item 9. The present invention may relate to the electrically heated carrier according to any one of Items 1 to 3, wherein the plurality of teeth are formed so that the electrical resistances thereof differ from one another depending on the dimensions of the thermally sprayed fixing layer. [Effects of the Invention]

[0015] According to one embodiment of the electrically heated carrier of the present invention, the multiple tooth portions are formed so that the difference in current flowing through each of the multiple tooth portions is smaller than when the electrical resistances of each of the multiple proximal connecting tooth portions are equal to each other and the electrical resistances of each of the multiple distal connecting tooth portions are equal to each other, thereby suppressing imbalance in the life of the sprayed fixing layer and achieving a longer life of the sprayed fixing layer. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing a honeycomb structure of an electrically heated carrier according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a plan view showing a first embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 3] 1. FIG. 4 is a plan view showing a second embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 4] FIG. 4 is a cross-sectional view of the metal electrode taken along line IV-IV in FIG. 3. [Figure 5] 1. FIG. 4 is a plan view showing a third embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 6] FIG. 6 is a cross-sectional view of the metal electrode taken along line VI-VI in FIG. 5. [Figure 7] 1. FIG. 4 is a plan view showing a fourth embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 8] FIG. 8 is a cross-sectional view of the metal electrode taken along line VIII-VIII in FIG. 7. [Figure 9]1. FIG. 4 is a plan view showing a fifth embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 10] FIG. 10 is a cross-sectional view of the metal electrode taken along line XX in FIG. 9. [Figure 11] 1. FIG. 4 is a plan view showing a sixth embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 12] 12 is a side view of the metal electrode taken along arrows A to D in FIG. [Figure 13] 1. FIG. 4 is a plan view showing a seventh embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 14] 1. FIG. 4 is a plan view showing an eighth embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 15] 1. FIG. 4 is a plan view showing a ninth embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 16] FIG. 2 is a plan view showing a tenth embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 17] 1. FIG. 4 is a plan view showing an eleventh embodiment of a metal electrode fixed to the honeycomb structure of FIG. [Figure 18] 18 is a cross-sectional view of the metal electrode taken along line XVIII-XVIII in FIG. 17. [Figure 19] FIG. 10 is a plan view showing a metal electrode 2 fixed to a honeycomb structure of an electrically heated carrier according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to each embodiment, and the components can be modified and embodied without departing from the spirit of the present invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in each embodiment. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components of different embodiments may be appropriately combined.

[0018] Embodiment 1 FIG. 1 is a perspective view showing a honeycomb structure 1 of an electrically heated carrier according to a first embodiment of the present invention. The honeycomb structure 1 shown in FIG. 1 constitutes a part of the electrically heated carrier. The electrically heated carrier generates heat in the honeycomb structure 1 by passing electricity through it, thereby raising the temperature of the catalyst supported on the honeycomb structure 1 to an activation temperature before starting the engine. The electrically heated carrier can be installed in the exhaust path of an automobile, for example, and used to purify exhaust gas emitted from the engine.

[0019] The honeycomb structure 1 has a honeycomb structure part 10 and a pair of electrode layers 11.

[0020] The honeycomb structure 10 is a columnar member made of ceramics, and has an outer peripheral wall 100 and partition walls 101 disposed inside the outer peripheral wall 100 to define a plurality of cells 101a that form flow paths extending from one end face to the other end face. The columnar shape can be understood as a three-dimensional shape having a thickness in the flow path direction of the cells 101a (axial direction of the honeycomb structure 10). The ratio (aspect ratio) of the axial length of the honeycomb structure 10 to the diameter or width of the end face of the honeycomb structure 10 is arbitrary. The columnar shape may include a shape (flat shape) in which the axial length of the honeycomb structure 10 is shorter than the diameter or width of the end face.

[0021] The outer shape of the honeycomb structure 10 is not particularly limited as long as it is columnar, and can be other shapes such as a columnar shape with circular end faces (cylindrical shape), a columnar shape with oval end faces, a columnar shape with polygonal end faces (quadragonal, pentagonal, hexagonal, heptagonal, octagonal, etc.), etc. The size of the honeycomb structure 10 is set to 2000 to 20000 mm2 in order to increase heat resistance (suppress cracks in the circumferential direction of the outer peripheral wall 100). 2 It is preferable that the thickness is 5000 to 15000 mm 2 It is more preferable that:

[0022] Although there are no limitations on the shape of the cells 101a in a cross section perpendicular to the flow direction of the cells 101a, a square, a hexagon, an octagon, or a combination thereof is preferred. Among these, a square and a hexagon are preferred. By using such a cell shape, the pressure loss when exhaust gas flows through the honeycomb structure portion 10 is reduced, and the purification performance of the catalyst is improved.

[0023] The thickness of the partition walls 101 that define the cells 101a is preferably 0.1 to 0.3 mm, and more preferably 0.1 to 0.2 mm. When the thickness of the partition walls 101 is 0.1 mm or more, it is possible to prevent a decrease in the strength of the honeycomb structure section 10. When the thickness of the partition walls 101 is 0.3 mm or less, it is possible to prevent an increase in pressure loss when exhaust gas flows through the honeycomb structure section 10 when the honeycomb structure section 10 is used as a catalyst carrier and a catalyst is carried thereon. In the present invention, the thickness of the partition walls 101 is defined as the length of a portion of a line segment that connects the centers of gravity of adjacent cells 101a and that passes through the partition walls 101 in a cross section perpendicular to the flow path direction of the cells 101a.

[0024] The honeycomb structure 10 has a cell density of 40 to 150 cells / cm in a cross section perpendicular to the flow path direction of the cells 101a. 2 It is preferable that the number of cells is 70 to 100. 2 By setting the cell density in this range, it is possible to increase the purification performance of the catalyst while minimizing the pressure loss when exhaust gas flows through it. 2 If the cell density is 150 cells / cm or more, a sufficient catalyst carrying area is ensured. 2 When the honeycomb structure 10 is used as a catalyst carrier and a catalyst is carried thereon, excessive pressure loss during the flow of exhaust gas is suppressed if the honeycomb structure 10 is not more than this value. The cell density is a value obtained by dividing the number of cells by the area of ​​one end face portion of the honeycomb structure 10 excluding the outer peripheral wall 100 portion.

[0025] Providing the outer peripheral wall 100 of the honeycomb structure 10 is useful from the viewpoint of ensuring the structural strength of the honeycomb structure 10 and suppressing leakage of the fluid flowing through the cells 101a from the outer peripheral wall 100. Specifically, the thickness of the outer peripheral wall 100 is preferably 0.05 mm or more, more preferably 0.10 mm or more, and even more preferably 0.15 mm or more. However, if the outer peripheral wall 100 is too thick, it will have too high strength, which will disrupt the strength balance with the partition walls 101 and reduce thermal shock resistance. Therefore, the thickness of the outer peripheral wall 100 is preferably 1.0 mm or less, more preferably 0.7 mm or less, and even more preferably 0.5 mm or less. Here, the thickness of the outer peripheral wall 100 is defined as the thickness in the direction normal to the tangent of the outer peripheral wall 100 at the measurement point when the portion of the outer peripheral wall 100 whose thickness is to be measured is observed in a cross section perpendicular to the flow path direction of the cells 101a.

[0026] The honeycomb structure part 10 is preferably made of ceramics and has electrical conductivity. There are no particular restrictions on the volume resistivity of the honeycomb structure part 10 as long as it can generate heat by Joule heat when current is applied, but it is preferably 0.1 to 200 Ωcm, and more preferably 1 to 200 Ωcm. In the present invention, the volume resistivity of the honeycomb structure part 10 is a value measured at 25°C by a four-terminal method.

[0027] The material of the honeycomb structure member 10 is not limited, but can be selected from the group consisting of oxide ceramics such as alumina, mullite, zirconia, and cordierite, and non-oxide ceramics such as silicon carbide, silicon nitride, and aluminum nitride. Silicon carbide-silicon composites and silicon carbide / graphite composites can also be used. Among these, from the viewpoint of achieving both heat resistance and electrical conductivity, it is preferable that the material of the honeycomb structure member 10 contains a silicon-silicon carbide composite or a ceramic containing silicon carbide as the main component. When the material of the honeycomb structure member 10 is said to contain a silicon-silicon carbide composite as the main component, it means that the honeycomb structure member 10 contains 90 mass% or more of the silicon-silicon carbide composite (total mass) of the entire honeycomb structure member 10. Here, the silicon-silicon carbide composite material contains silicon carbide particles as aggregate and silicon as a binder that bonds the silicon carbide particles, and it is preferable that a plurality of silicon carbide particles are bonded by the silicon so as to form pores between the silicon carbide particles. When the material of the honeycomb structure part 10 is said to be mainly composed of silicon carbide, it means that the honeycomb structure part 10 contains silicon carbide (total mass) in an amount of 90 mass% or more of the entire material.

[0028] When the honeycomb structure 10 contains a silicon-silicon carbide composite material, the ratio of the "mass of silicon as a binder" contained in the honeycomb structure 10 to the sum of the "mass of silicon carbide particles as aggregate" contained in the honeycomb structure 10 and the "mass of silicon as a binder" contained in the honeycomb structure 10 is preferably 10 to 40 mass%, and more preferably 15 to 35 mass%.

[0029] The outer peripheral wall 100 and the partition walls 101 may be porous. If they are porous, the porosity of the outer peripheral wall 100 and the partition walls 101 is preferably 35 to 60%, and more preferably 35 to 45%. The porosity is a value measured with a mercury porosimeter. Furthermore, the outer peripheral wall 100 and the partition walls 101 may be dense, and if they are dense, the porosity of the outer peripheral wall 100 and the partition walls 101 may be 10% or less, or 5% or less.

[0030] The average pore diameter of the outer wall 100 and the partition walls 101 of the honeycomb structure portion 10 is preferably 2 to 15 μm, and more preferably 4 to 8 μm. The average pore diameter is a value measured by a mercury porosimeter.

[0031] A pair of electrode layers 11 are provided on the surface of the outer peripheral wall 100. The electrode layers 11, together with the outer peripheral wall 100, form the outer peripheral surface of the honeycomb structure 1. The electrode layers 11 of this embodiment are provided spaced apart from each other in the circumferential direction of the honeycomb structure section 10. More specifically, the electrode layers 11 are provided on either side of the central axis of the honeycomb structure section 10. Only one of the pair of electrode layers 11 is shown in FIG. 1 .

[0032] The pair of electrode layers 11 in this embodiment each have a separator 110 and first and second partial electrode layers 111, 112 separated by the separator 110. The separator 110 may be a slit provided between the first and second partial electrode layers 111, 112. The slit may be filled with a material having a higher volume resistivity than the first and second partial electrode layers 111, 112. The separator 110 and the first and second partial electrode layers 111, 112 extend from one end to the other end of the honeycomb structure section 10 in the flow path direction of the cell 101a. The first and second partial electrode layers 111, 112 are strip-shaped with a predetermined width in the circumferential direction of the honeycomb structure section 10, and the separator 110 is linear and narrower than the first and second partial electrode layers 111, 112. However, the method of arranging the separator 110 and the first and second partial electrode layers 111, 112 is not limited to this form as long as they can be connected to a pair of metal electrodes 2 described below.

[0033] As will be described later, in the electrically heated carrier of this embodiment, a metal electrode 2 (see FIG. 2) is fixed on an electrode layer 11. Although not shown, an external power source such as a battery can be connected to the metal electrode 2 via a power cable. By applying a voltage to the honeycomb structure part 10 through the metal electrode 2 and the electrode layer 11, the honeycomb structure part 10 can be made to generate heat.

[0034] From the viewpoint of making it easier for electricity to flow through the electrode layers 11, the volume resistivity of the electrode layers 11 is preferably 1 / 200 or more and 1 / 10 or less of the volume resistivity of the honeycomb structure portion 10.

[0035] The material of the electrode layer 11 can be a conductive ceramic, a metal, or a composite material (cermet) of a metal and a conductive ceramic. Examples of the metal include a single metal such as Cr, Fe, Co, Ni, Si, or Ti, or an alloy containing at least one metal selected from the group consisting of these metals. Examples of the conductive ceramic include, but are not limited to, silicon carbide (SiC), and metal compounds such as metal silicides such as tantalum silicide (TaSi2) and chromium silicide (CrSi2).

[0036] The honeycomb structure 1 having the electrode layer 11 is manufactured by first applying an electrode layer forming raw material containing a ceramic raw material to the side surface of a dried honeycomb body and drying the applied material to form a pair of unfired electrode layers extending in a band shape in the flow path direction of the cells on the outer surface of the peripheral wall, sandwiching the central axis of the dried honeycomb body, to manufacture a dried honeycomb body with unfired electrode layers. Next, the dried honeycomb body with the unfired electrode layers is fired to manufacture a fired honeycomb body with a pair of electrode layers. This produces a honeycomb structure 1 having the electrode layer 11.

[0037] By supporting a catalyst on the honeycomb structure 10, the electrically heated carrier can be used as a catalyst body. Examples of the catalyst include precious metal catalysts and other catalysts. Precious metal catalysts include three-way catalysts and oxidation catalysts in which precious metals such as platinum (Pt), palladium (Pd), and rhodium (Rh) are supported on the surface of alumina pores and contain promoters such as ceria and zirconia, or alkaline earth metals and platinum are used to reduce nitrogen oxides (NO x ) as a storage component of NO x Examples of catalysts that do not use precious metals include NOx storage reduction catalysts (LNT catalysts) containing copper-substituted or iron-substituted zeolites. xExamples include selective catalytic reduction catalysts (SCR catalysts). Two or more catalysts selected from these catalysts may be used. There are no particular limitations on the method for supporting the catalyst, and the method can be carried out in accordance with the conventional method for supporting a catalyst on the honeycomb structure 1.

[0038] Next, FIG. 2 is a plan view showing a first embodiment of a metal electrode 2 fixed to the honeycomb structure 1 of FIG. 1. The electrically heated carrier of this embodiment includes the above-mentioned honeycomb structure 1 and a pair of metal electrodes 2 connected to the electrode layer 11 for applying a voltage to the honeycomb structure 1. FIG. 2 shows a main part of the electrically heated carrier according to this embodiment of the present invention, showing a state in which one metal electrode 2 is connected to one electrode layer 11. Another metal electrode 2 is similarly fixed to the other electrode layer 11. One of the pair of metal electrodes 2 is treated as an anode, and the other is treated as a cathode. In other words, a current flows from one metal electrode 2 through the honeycomb structure 1 to the other metal electrode 2.

[0039] Each of the pair of metal electrodes 2 has a base 20 and a comb-like connecting portion 21 having a plurality of teeth 22 extending from the base 20. The plurality of teeth 22 includes a tooth body 22a and a plurality of sprayed fixing layers 22b that connect each of the tooth bodies 22a to the electrode layer 11.

[0040] The base 20 may be a longitudinal plate. The metal electrodes 2 may be arranged on the outer peripheral surface of the honeycomb structure 1 so that the extension direction 20E (longitudinal direction) of the base 20 is along the flow path direction of the cells 101a. In this case, the width direction 20W of the base 20, which is perpendicular to the extension direction 20E, may extend in the circumferential direction of the honeycomb structure 1. Furthermore, each metal electrode 2 may be arranged on the outer peripheral surface of the honeycomb structure 1 so that the base 20 is located outside the electrode layer 11 (outside either one of the first and second partial electrode layers 111, 112) with respect to the circumferential direction of the honeycomb structure 1.

[0041] The connecting portion 21 is a portion that is fixed to the honeycomb structure 1 and electrically connected to the honeycomb structure 1. The connecting portion 21 in this embodiment is connected to the electrode layer 11 of the honeycomb structure 1. More specifically, the connecting portion 21 is connected to the first and second partial electrode layers 111, 112. At least the base portion 20 and the connecting portion 21 may be formed in an arc shape so as to fit along the outer peripheral surface of the honeycomb structure 1.

[0042] As described above, the connection portion 21 has a comb-like shape having a plurality of teeth 22 extending from the base portion 20. The tooth portion bodies 22a of each tooth portion 22 are spaced apart from each other in the extending direction 20E of the base portion 20 and extend from one end of the base portion 20 in the width direction 20W. The tooth portion bodies 22a may be formed integrally with the base portion 20 by a plate body. The extending direction 22E of the tooth portion bodies 22a from the base portion 20 may be the same direction as the width direction 20W of the base portion 20. The extending length of each tooth portion body 22a from the base portion 20 can be equal to or greater than the extending width of the electrode layer 11 in the circumferential direction of the honeycomb structure 1.

[0043] As described above, each sprayed fixing layer 22b connects each tooth portion body 22a to the electrode layer 11. Furthermore, each sprayed fixing layer 22b fixes each tooth portion body 22a to the electrode layer 11. Each sprayed fixing layer 22b can be formed by spraying a sprayed material onto the outer peripheral surface (electrode layer 11) of the honeycomb structure 1 and each tooth portion body 22a in a state in which each tooth portion body 22a is placed on the outer peripheral surface of the honeycomb structure 1. The sprayed fixing layer 22b is provided on the outer peripheral surface (electrode layer 11) of the honeycomb structure 1 and each tooth portion body 22a so as to straddle each tooth portion 22 in the width direction 22W of the tooth portion 22. The width direction 22W of the tooth portion 22 is a direction perpendicular to the extension direction 22E of the tooth portion 22 and may be the same direction as the extension direction 20E of the base portion 20.

[0044] The plurality of tooth portions 22 include a plurality of proximal connection tooth portions 220p, 221p connected to the electrode layer 11 at first positions in the extension direction 22E of the tooth portions 22, and a plurality of distal connection tooth portions 220d, 221d connected to the electrode layer 11 at second positions farther from the base portion 20 than the first positions in the extension direction 22E of the tooth portions 22. In the illustrated embodiment, the three tooth portions 22 connected to the first partial electrode layer 111 are the proximal connection tooth portions 220p, 221p, and the four tooth portions 22 connected to the second partial electrode layer 112 are the distal connection tooth portions 220d, 221d.

[0045] Each of the pair of metal electrodes 2 may further have a lead portion 24 drawn out from the base 20. The lead portion 24 extends from the other end of the base 20 in the width direction 20W. That is, the lead portion 24 and the tooth portion 22 extend in opposite directions around the base 20. The lead portion 24 may be formed integrally with the base 20 and the tooth portion main body 22a by a plate body. The lead portion 24 may be tongue-shaped as shown. The lead portion 24 is fixed to the honeycomb structure 1 via the base 20 and the connecting portion 21, and the lead portion 24 itself may be provided to be flexible. An external power source may be connected to the lead portion 24 via a power cable (not shown).

[0046] A sprayed base layer may be provided on the upper surface of the electrode layer 11, i.e., between the electrode layer 11 and the metal electrode 2, to improve the adhesion of the sprayed fixing layer 22b. When the sprayed base layer is provided on the upper surface of the electrode layer 11, the sprayed base layer can form the outer peripheral surface of the honeycomb structure 1. Even when a sprayed base layer is provided, the metal electrode 2 is still connected or fixed to the honeycomb structure 1.

[0047] The thermal sprayed fixing layer 22b and the thermal sprayed base layer can be formed of conductive ceramics. Examples of conductive ceramics constituting the thermal sprayed base layer include, but are not limited to, silicon carbide (SiC), metal compounds such as metal silicides (tantalum silicide (TaSi2) and chromium silicide (CrSi2), and composites (cermets) containing one or more metals. Specific examples of cermets include composites of metal silicon and silicon carbide, composites of metal silicides (tantalum silicide, chromium silicide, etc.) and metal silicon and silicon carbide, and composites in which one or more of the above metals are added with one or more insulating ceramics (such as alumina, mullite, zirconia, cordierite, silicon nitride, bentonite, and aluminum nitride) to reduce thermal expansion. In addition to the above metals, heat-resistant metals such as aluminum or chromium-containing metals, stainless steel, or Ni-Cr alloys can also be used.

[0048] When the comb-shaped metal electrode 2 is connected to the electrode layer 11 of the honeycomb structure 1, the current flowing through each tooth 22 tends to vary depending on the position of each tooth 22 constituting the comb teeth and the connection position of each tooth with the electrode layer 11. When electricity is repeatedly applied to the metal electrode 2, the resistance of the sprayed fixing layer 22b of the tooth 22 through which more current flows increases more quickly and the tooth 22 no longer conducts electricity (reaching the end of its life), and accordingly the current in the other tooth 22 increases, shortening the life of the sprayed fixing layer 22b of the other tooth 22.

[0049] In the electrically heated carrier of this embodiment, the multiple teeth 22 are formed so that the difference in current flowing through each of the multiple teeth 22 is smaller than when the electrical resistances of the multiple proximal connection teeth 220p, 221p are equal and the electrical resistances of the multiple distal connection teeth 220d, 221d are equal. This reduces the deviation in the life of the sprayed fixing layer 22b and extends the life of the sprayed fixing layer 22b. The electrical resistance of each tooth 22 can be calculated by separating the tooth 22 from the base 20, passing a predetermined current between the end of the tooth 22 on the base 20 side and the electrode layer 11 closest to the sprayed fixing layer 22b provided on the tooth 22, and measuring the voltage between the base end and the sprayed fixing layer 22b. Ideally, the voltage measurement probe should be placed between the sprayed fixing layer 22b and the electrode layer 11, but since it is physically difficult to place it in that position, it is preferable to place it as close as possible to the sprayed fixing layer 22b on the electrode layer 11. Since the electrical resistance of each tooth portion 22 is often relatively small, it is preferable to use the four-terminal method as a method for measuring the electrical resistance.

[0050] The plurality of teeth 22 include a plurality of end teeth 220 arranged at both ends of the comb teeth in the extension direction 20E of the base 20, and a plurality of intermediate teeth 221 arranged between the end teeth 220, and the electrical resistance of the end teeth 220 is higher than the electrical resistance of the intermediate teeth 221. In the illustrated embodiment, seven teeth 22 are provided, with two on the upper side and two on the lower side in the figure, a total of four teeth 22 being end teeth 220. The three teeth 22 between these end teeth 220 are intermediate teeth 221.

[0051] When the electrical resistance of each tooth portion 22 is equal, more current tends to flow through the end tooth portion 220 than through the intermediate tooth portion 221. This is because the current flowing in the area outside the end tooth portion 220 in the extension direction 20E of the base portion 20 also passes through the end tooth portion 220. When the electrical resistance of the end tooth portion 220 is higher than the electrical resistance of the intermediate tooth portion 221, the values ​​of the currents flowing through the multiple tooth portions 22 can be more reliably made equal to each other, and the life of the sprayed fixing layer 22b can be more reliably extended. The electrical resistances of the end tooth portion 220 and the intermediate tooth portion 221 can be calculated by measuring the voltage values ​​as described above.

[0052] The multiple end teeth 220 include end proximal connection teeth 220p connected to the electrode layer 11 at first positions with respect to the extension direction 22E of the tooth portions 22, and end distal connection teeth 220d connected to the electrode layer 11 at second positions with respect to the extension direction 22E of the tooth portions 22. The end proximal connection teeth 220p may be arranged inside the end distal connection teeth 220d with respect to the extension direction 20E of the base 20. In the illustrated embodiment, the two end teeth 220 located outermost with respect to the extension direction 20E of the base 20 are the end distal connection teeth 220d connected to the second partial electrode layer 112. Furthermore, the two end teeth 220 arranged inside the end proximal connection teeth 220p with respect to the extension direction 20E of the base 20 are the end proximal connection teeth 220p connected to the first partial electrode layer 111.

[0053] The multiple intermediate teeth 221 arranged between the end teeth 220 include an intermediate proximal connection tooth 221p connected to the electrode layer 11 at a first position with respect to the extension direction 22E of the tooth portion 22, and an intermediate distal connection tooth 221d connected to the electrode layer 11 at a second position with respect to the extension direction 22E of the tooth portion 22. At least one of the intermediate proximal connection teeth 221p may be arranged inside the intermediate distal connection tooth 221d with respect to the extension direction 20E of the base 20. In the illustrated embodiment, the two intermediate teeth 221 arranged inside the end proximal connection tooth 220p with respect to the extension direction 20E of the base 20 are the intermediate distal connection tooth 221d connected to the second partial electrode layer 112. The one intermediate tooth 221 located between these intermediate distal connection tooth 221d is the intermediate proximal connection tooth 221p connected to the first partial electrode layer 111. In the illustrated embodiment, three intermediate tooth portions 221 are provided, but the number of intermediate tooth portions 221 may be four or more. For example, when five intermediate tooth portions 221 are provided, two or more intermediate proximal connecting tooth portions 221p may be disposed inside the intermediate distal connecting tooth portion 221d.

[0054] In this embodiment, the electrical resistance increases in the order of end proximal connection tooth 220p, end distal connection tooth 220d, intermediate proximal connection tooth 221p, and intermediate distal connection tooth 221d. The end proximal connection tooth 220p has the highest electrical resistance, and the intermediate distal connection tooth 221d has the lowest electrical resistance. This more reliably makes it possible to equalize the values ​​of the currents flowing through the multiple tooth portions 22, thereby more reliably extending the life of the sprayed fixing layer 22b.

[0055] The electrical resistance of each tooth portion 22 can be adjusted by any method. In the first embodiment of the metal electrode 2 shown in Fig. 2, the multiple tooth portions 22 are formed so that the electrical resistance varies depending on the width of the tooth portion body 22a. As shown in Fig. 2, the widths of the tooth portions 22 become narrower in the order of the end proximal connecting tooth portion 220p, the end distal connecting tooth portion 220d, the middle proximal connecting tooth portion 221p, and the middle distal connecting tooth portion 221d. The end proximal connecting tooth portion 220p has the narrowest width, and the middle distal connecting tooth portion 221d has the widest width.

[0056] Next, Fig. 3 is a plan view showing a second embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of Fig. 1, and Fig. 4 is a cross-sectional view of the metal electrode 2 taken along line IV-IV in Fig. 3. Furthermore, Fig. 5 is a plan view showing a third embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of Fig. 1, and Fig. 6 is a cross-sectional view of the metal electrode 2 taken along line VI-VI in Fig. 5.

[0057] In the second and third embodiments of the metal electrode 2 shown in Figures 3 to 6, the multiple tooth portions 22 are formed so that their electrical resistances differ from one another depending on the thickness of the additional member 22c added to the tooth portion main body 22a, the presence or absence of the additional member 22c, or the thickness of the tooth portion main body 22a itself.

[0058] In a second embodiment of the metal electrode 2 shown in FIGS. 3 and 4, the multiple teeth 22 are formed so that their electrical resistances differ from one another depending on the thickness of the additional member 22c added to the tooth body 22a or the presence or absence of the additional member 22c. The additional member 22c may be made of a conductive member. For example, the additional member 22c may be a conductive plate material, a conductive coating, and / or a conductive thermally sprayed film. The additional member 22c is added to the tooth body 22a where the electrical resistance should be reduced. The thickness of the additional member 22c is made thicker in the tooth body 22a where the electrical resistance should be further reduced. The additional member 22c may be added to the tooth body 22a between the base end of the tooth body 22a on the base portion 20 side and the thermally sprayed fixing layer 22b provided on the tooth body 22a.

[0059] As described above, in this embodiment, the electrical resistance increases in the order of the end proximal connection tooth 220p, the end distal connection tooth 220d, the intermediate proximal connection tooth 221p, and the intermediate distal connection tooth 221d. The additional member 22c is not added to the end proximal connection tooth 220p, but is added to the end distal connection tooth 220d, the intermediate proximal connection tooth 221p, and the intermediate distal connection tooth 221d. The thickness of the additional member 22c decreases in the order of the end distal connection tooth 220d, the intermediate proximal connection tooth 221p, and the intermediate distal connection tooth 221d. The thickness of the additional member 22c is thinnest at the end distal connection tooth 220d and thickest at the intermediate distal connection tooth 221d.

[0060] 5 and 6, the tooth portions 22 are formed so that their electrical resistances differ from one another depending on the thickness of the tooth portion bodies 22a themselves. The thicknesses of the tooth portion bodies 22a decrease in the order of the end proximal connection tooth 220p, the end distal connection tooth 220d, the intermediate proximal connection tooth 221p, and the intermediate distal connection tooth 221d. The tooth portion bodies 22a are thinnest at the end proximal connection tooth 220p and thickest at the intermediate distal connection tooth 221d.

[0061] Next, Fig. 7 is a plan view showing a fourth embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of Fig. 1, and Fig. 8 is a cross-sectional view of the metal electrode 2 taken along line VIII-VIII in Fig. 7. Furthermore, Fig. 9 is a plan view showing a fifth embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of Fig. 1, and Fig. 10 is a cross-sectional view of the metal electrode 2 taken along line XX in Fig. 9.

[0062] 7 to 10, the teeth 22 are formed to have different electrical resistances depending on the material of the tooth body 22a itself or the material of the additional member 22c added to the tooth body 22a. In the figures, different shading indicates different materials.

[0063] In the fourth embodiment of the metal electrode 2 shown in Figures 7 and 8, the tooth portions 22 are formed so that their electrical resistances differ from one another depending on the material of the tooth portion bodies 22a themselves. In other words, the tooth portion bodies 22a of the tooth portions 22 are formed from materials with different electrical resistances. The electrical resistances of the material of the tooth portion bodies 22a increase in the order of the end proximal connection tooth 220p, the end distal connection tooth 220d, the middle proximal connection tooth 221p, and the middle distal connection tooth 221d. The electrical resistance of the material of the tooth portion body 22a of the end proximal connection tooth 220p is the highest, and the electrical resistance of the material of the tooth portion body 22a of the middle distal connection tooth 221d is the lowest.

[0064] In the fifth embodiment of the metal electrode 2 shown in FIGS. 9 and 10, the tooth portions 22 are formed so that their electrical resistances differ from one another due to the material of the additional member 22c added to the tooth portion main body 22a. In other words, the additional member 22c of each tooth portion 22 is formed from a material with a different electrical resistance from one another. The additional member 22c does not need to be added to the end proximal connection tooth portion 220p. The electrical resistance of the material of the additional member 22c increases in the order of the end distal connection tooth portion 220d, the intermediate proximal connection tooth portion 221p, and the intermediate distal connection tooth portion 221d. The electrical resistance of the material of the additional member 22c of the end distal connection tooth portion 220d is the highest, and the electrical resistance of the material of the additional member 22c of the intermediate distal connection tooth portion 221d is the lowest.

[0065] Next, Fig. 11 is a plan view showing a sixth embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of Fig. 1, and Fig. 12 is a side view of the metal electrode 2 along the arrows A to D of Fig. 11. Furthermore, Fig. 13 is a plan view showing a seventh embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of Fig. 1.

[0066] In the sixth and seventh embodiments of the metal electrode 2 shown in Figures 11 to 13, the multiple tooth portions 22 are formed so that their electrical resistances are different from one another by having the tooth portion main body 22a bent in the thickness direction 22T to form an accordion shape, or by having the tooth portion main body 22a snake in the extension direction of the base 20, thereby changing the current path length from the base 20 to the sprayed fixing layer 22b.

[0067] In a sixth embodiment of the metal electrode 2 shown in Figures 11 and 12, the tooth portions 22 are formed such that the tooth portion main body 22a is bent in the thickness direction 22T to form an accordion-like shape, thereby varying the current path length from the base portion 20 to the sprayed fixing layer 22b and thereby varying the electrical resistance. The current path lengths are longest in the order of the end proximal connection tooth 220p, the end distal connection tooth 220d, the intermediate proximal connection tooth 221p, and the intermediate distal connection tooth 221d. The end proximal connection tooth 220p has the longest current path length, and the intermediate distal connection tooth 221d has the shortest current path length. The intermediate distal connection tooth 221d, which has the shortest current path length, may be flat.

[0068] The bellows-shaped end proximal connection tooth portion 220p, end distal connection tooth portion 220d, and intermediate proximal connection tooth portion 221p may have peaks 22d protruding on one side (front side) in the thickness direction 22T and valleys 22f between the peaks 22d. The current path length can be changed by changing the spacing between the peaks 22d (bellows period) and / or the height of the peaks 22d (bellows amplitude). The shorter the spacing between the peaks 22d (bellows period) and the higher the height of the peaks 22d (bellows amplitude), the longer the current path length. The peaks 22d may be formed higher in a direction away from the honeycomb structure 1 than in a direction approaching the honeycomb structure 1 from a reference position.

[0069] In the seventh embodiment of the metal electrode 2 shown in Fig. 13, the tooth bodies 22a of the multiple teeth 22 are snaked in the extending direction 20E of the base 20, thereby varying the current path lengths from the base 20 to the sprayed fixing layer 22b, and thus forming tooth portions 22 with different electrical resistances. The current path lengths are longest in the order of the end proximal connection tooth 220p, the end distal connection tooth 220d, the intermediate proximal connection tooth 221p, and the intermediate distal connection tooth 221d. The end proximal connection tooth 220p has the longest current path length, and the intermediate distal connection tooth 221d has the shortest current path length. The intermediate distal connection tooth 221d, which has the shortest current path length, may be linear.

[0070] The meandering end proximal connection tooth 220p, end distal connection tooth 220d, and intermediate proximal connection tooth 221p may have a first detour 22g toward one side in the extension direction 20E of the base 20 and a second detour 22h toward the other side in the extension direction 20E of the base 20. The current path length can be changed by changing the number or frequency of switching between the first detour 22g and the second detour 22h. The current path length can also be changed by changing the lengths of the first detour 22g and the second detour 22h in the extension direction 20E of the base 20. The first detour path 22g and the second detour path 22h may be spaced apart from each other in the extension direction 22E of the tooth portion 22, as in the end distal connection tooth portion 220d in the figure, or may be adjacent to each other in the extension direction 22E of the tooth portion 22, as in the end proximal connection tooth portion 220p and the intermediate proximal connection tooth portion 221p in the figure. Even when the first detour path 22g and the second detour path 22h are adjacent to each other, they are separated by the slit 22j.

[0071] Next, FIG. 14 is a plan view showing an eighth embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of FIG. 1. In the eighth embodiment of the metal electrode 2 shown in FIG. 14, the multiple tooth portions 22 are formed so that the electrical resistances differ from one another depending on the material of the sprayed fixing layer 22b. In the figure, different shading indicates different materials of the sprayed fixing layer 22b. In other words, the sprayed fixing layer 22b of each tooth portion 22 is formed from a material with a different electrical resistance from one another. The electrical resistance of the material of the sprayed fixing layer 22b increases in the order of the end proximal connection tooth 220p, the end distal connection tooth 220d, the intermediate proximal connection tooth 221p, and the intermediate distal connection tooth 221d. The electrical resistance of the material of the sprayed fixing layer 22b of the end proximal connection tooth 220p is the highest, and the electrical resistance of the material of the sprayed fixing layer 22b of the intermediate distal connection tooth 221d is the lowest.

[0072] Next, Fig. 15 is a plan view showing a ninth embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of Fig. 1. Also, Fig. 16 is a plan view showing a tenth embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of Fig. 1. Also, Fig. 17 is a plan view showing an eleventh embodiment of the metal electrode 2 fixed to the honeycomb structure 1 of Fig. 1, and Fig. 18 is a cross-sectional view of the metal electrode 2 taken along line XVIII-XVIII in Fig. 17.

[0073] In the ninth to eleventh embodiments of the metal electrode 2 shown in FIGS. 15 to 18, the teeth 22 are formed so that the electrical resistances thereof differ from one another depending on the dimensions of the sprayed fixing layer 22b.

[0074] 15, the tooth portions 22 are formed so that their electrical resistances differ from one another depending on the dimensions of the sprayed fixing layers 22b in the extension direction 22E of the tooth portions 22. The dimensions of the sprayed fixing layers 22b in the extension direction 22E of the tooth portions 22 are smallest for the end proximal connection tooth portion 220p, the end distal connection tooth portion 220d, the intermediate proximal connection tooth portion 221p, and the intermediate distal connection tooth portion 221d in this order. The dimension of the sprayed fixing layer 22b in the extension direction 22E of the tooth portions 22 is smallest for the end proximal connection tooth portion 220p and largest for the intermediate distal connection tooth portion 221d.

[0075] 16, the tooth portions 22 are formed so that their electrical resistances differ depending on the dimensions of the sprayed fixing layer 22b in the extending direction 20E of the base 20 (the width direction 22W of the tooth portions 22). The dimensions of the sprayed fixing layer 22b in the extending direction 20E of the base 20 are smallest for the end proximal connection tooth 220p, the end distal connection tooth 220d, the middle proximal connection tooth 221p, and the middle distal connection tooth 221d in this order. The dimension of the sprayed fixing layer 22b in the extending direction 20E of the base 20 is smallest for the end proximal connection tooth 220p and largest for the middle distal connection tooth 221d.

[0076] 17 and 18, the tooth portions 22 are formed so that their electrical resistances differ from one another depending on the dimensions of the sprayed fixing layers 22b in the thickness direction 22T of the tooth portions 22. The dimensions of the sprayed fixing layers 22b in the thickness direction 22T of the tooth portions 22 are smallest for the end proximal connection tooth portion 220p, the end distal connection tooth portion 220d, the intermediate proximal connection tooth portion 221p, and the intermediate distal connection tooth portion 221d in this order. The dimension of the sprayed fixing layer 22b in the thickness direction 22T of the tooth portion 22 is smallest for the end proximal connection tooth portion 220p and largest for the intermediate distal connection tooth portion 221d.

[0077] Although the first to eleventh embodiments of the metal electrode 2 have been described individually above, at least two of the first to eleventh embodiments may be combined. For example, the width of the tooth portion main body 22a may be varied between each tooth portion 22 as in the first embodiment, while the thickness and / or presence or absence of the additional member 22c added to the tooth portion main body 22a may be varied between each tooth portion 22 as in the second embodiment. Furthermore, the width of the tooth portion main body 22a may be varied in some tooth portions 22, while the thickness and / or presence or absence of the additional member 22c added to the tooth portion main body 22a in other tooth portions 22 may be varied.

[0078] Embodiment 2 Fig. 19 is a plan view showing a metal electrode 2 fixed to a honeycomb structure 1 of an electrically heated carrier according to a second embodiment of the present invention. As shown in Fig. 19, each of a pair of metal electrodes 2 may have a first electrode body 31 connected to a first partial electrode layer 111 and a second electrode body 32 connected to a second partial electrode layer 112. Each of the first electrode body 31 and the second electrode body 32 has a plurality of end tooth portions 220 and a plurality of intermediate tooth portions 221. The plurality of end tooth portions 220 and the plurality of intermediate tooth portions 221 are located at the same positions in the extension direction 22E of the tooth portion 22 connected to the electrode layer 11.

[0079] That is, in the first embodiment, one metal electrode 2 is connected to the first partial electrode layer 111 and the second partial electrode layer 112, and thereby the end proximal connection tooth 220p, the end distal connection tooth 220d, the intermediate proximal connection tooth 221p, and the intermediate distal connection tooth 221d are provided on the metal electrode 2. However, although the metal electrode 2 of the second embodiment has the end tooth 220 and the intermediate tooth 221, there is no distinction among them such as the end proximal connection tooth 220p, the end distal connection tooth 220d, the intermediate proximal connection tooth 221p, and the intermediate distal connection tooth 221d.

[0080] Even in such a configuration, the electrical resistance of the end tooth portion 220 may be higher than the electrical resistance of the intermediate tooth portion 221. By arbitrarily implementing one or more of the above-described first to eleventh aspects, the electrical resistance of each tooth portion 22 can be adjusted. The rest is the same as in the first embodiment.

[0081] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention. [Explanation of symbols]

[0082] 1: Honeycomb structure 10: Honeycomb structure 11: Electrode layer 100: Outer wall 101: Bulkhead 101a: Cell 2: Metal electrode 20: Base 21: Connection part 22: Tooth 22a: Tooth body 22b: Thermal sprayed fixing layer 22c: Additional member 220: End teeth 220d: distal end connecting tooth 220p: End proximal connecting tooth 221: Intermediate teeth 221d: Intermediate distal connecting tooth 221p: Intermediate proximal connecting tooth

Claims

1. a honeycomb structure including: a honeycomb structure part having an outer peripheral wall; partition walls disposed inside the outer peripheral wall and defining a plurality of cells that form flow paths extending from one end face to the other end face; and a pair of electrode layers provided on a surface of the outer peripheral wall; a pair of metal electrodes connected to the electrode layer for applying a voltage to the honeycomb structure; Equipped with each of the pair of metal electrodes has a base and a comb-like connecting portion having a plurality of teeth extending from the base, the plurality of teeth including a tooth body and a plurality of sprayed fixing layers connecting each of the tooth bodies to the electrode layer; The plurality of teeth include: a plurality of proximal connection teeth connected to the electrode layer at first positions in an extension direction of the teeth; a plurality of distal connection teeth connected to the electrode layer at a second position farther from the base than the first position in the extension direction of the teeth; It has the plurality of tooth portions are formed so that a difference in current flowing through each of the plurality of tooth portions is smaller than when the electrical resistances of the plurality of proximal connection tooth portions are equal to each other and the electrical resistances of the plurality of distal connection tooth portions are equal to each other. Electrically heated carrier.

2. The plurality of teeth include: a plurality of end teeth arranged at both ends of the comb teeth in the extending direction of the base; a plurality of intermediate teeth disposed between the end teeth; It has The electrical resistance of the end tooth portion is higher than the electrical resistance of the intermediate tooth portion.

2. An electrically heated carrier according to claim 1.

3. The plurality of end teeth are an end-proximal connecting tooth connected to the electrode layer at the first position in the extending direction of the tooth; an end distal connection tooth connected to the electrode layer at the second position with respect to the extension direction of the tooth; It has The plurality of intermediate teeth include: a middle proximal connecting tooth connected to the electrode layer at the first position in the extending direction of the tooth; an intermediate distal connecting tooth connected to the electrode layer at the second position in the extending direction of the tooth; It has the end proximal connecting tooth portion is disposed inside the end distal connecting tooth portion in the extending direction of the base portion; At least one of the intermediate proximal connecting teeth is disposed inside the intermediate distal connecting teeth with respect to the extending direction of the base, The electrical resistance increases in the order of the end proximal connecting tooth, the end distal connecting tooth, the intermediate proximal connecting tooth, and the intermediate distal connecting tooth.

3. An electrically heated carrier according to claim 2.

4. The plurality of teeth are formed so that the electrical resistances thereof differ from one another depending on the width of the tooth body.

4. An electrically heated carrier according to any one of claims 1 to 3.

5. The plurality of tooth portions are formed so that their electrical resistances differ from one another depending on the thickness of an additional member added to the tooth portion main body, the presence or absence of the additional member, or the thickness of the tooth portion main body itself.

4. An electrically heated carrier according to any one of claims 1 to 3.

6. The plurality of teeth are formed so as to have different electrical resistances from one another depending on the material of the tooth body itself or the material of an additional member added to the tooth body.

4. An electrically heated carrier according to any one of claims 1 to 3.

7. The plurality of teeth are formed so as to have different electrical resistances from one another by bending the tooth body in a thickness direction to form an accordion shape, or by serpentining the tooth body in an extension direction of the base, thereby changing the current path lengths from the base to the sprayed fixing layer.

4. An electrically heated carrier according to any one of claims 1 to 3.

8. the plurality of tooth portions are formed so as to have different electrical resistances depending on the material of the thermal sprayed fixing layer; 4. An electrically heated carrier according to any one of claims 1 to 3.

9. The plurality of tooth portions are formed so that their electrical resistances differ from one another depending on the dimensions of the thermal sprayed fixing layer.

4. An electrically heated carrier according to any one of claims 1 to 3.

Images