JP2008212842A - Honeycomb filter and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a honeycomb filter which enables detection of a defect point and defect cause without installing a device for detecting a defect of the honeycomb filter on the downstream of the honeycomb filter. <P>SOLUTION: The honeycomb filter 100 comprises a honeycomb structure part 1 having partition walls 2 for defining and forming a plurality of cells 3 penetrating in the axial direction, and a defect detection part 7 having linear and/or conductive strips 4, 5 arranged in the honeycomb structure part 1, and enables detection of a defect of the honeycomb structure part 1 by detecting a change in the resistance value of the defect detection part 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a honeycomb filter and a manufacturing method thereof, and more specifically, a honeycomb capable of detecting a defect location and a cause of a defect without disposing a device for detecting a defect of the honeycomb filter downstream of the honeycomb filter. The present invention relates to a filter and a method for manufacturing such a honeycomb filter.

  Flue exhaust gas and diesel engine exhaust gas contain particulate matter (PM) such as soot, which causes air pollution. In order to remove these, a filter (diesel particulate filter: DPF) made of ceramic or the like is widely used. A ceramic DPF can be used for a long period of time. However, defects such as cracks may occur due to thermal deterioration or the like, and there is a possibility that particulate matter may leak even though the amount is small. When such a defect occurs, it is extremely important from the viewpoint of preventing air pollution to immediately detect the occurrence of the defect and recognize the abnormality of the apparatus.

As a method for detecting the occurrence of such a defect, there is a method of providing a particulate matter detection device on the downstream side of the DPF (see, for example, Patent Document 1).
JP 60-123761 A

  As described above, when a device for detecting particulate matter is provided on the downstream side of the DPF, it is necessary to prepare a complicated device for detecting particulate matter separately from the DPF, resulting in an increase in cost. In addition, it is necessary to secure an extra space for installing the device.

  The present invention has been made in view of the above-described problems, and can detect a defect location and a defect cause without disposing a device for detecting a defect of the honeycomb filter on the downstream side of the honeycomb filter. A honeycomb filter and a method for manufacturing such a honeycomb filter are provided.

  In order to achieve the above object, the present invention provides the following honeycomb filter and method for manufacturing the honeycomb filter.

[1] A honeycomb structure portion having partition walls that partition and form a plurality of cells penetrating in the axial direction, and a defect detection portion having a linear and / or strip-shaped conductive member disposed in the honeycomb structure portion. A honeycomb filter capable of detecting defects in the honeycomb structure portion by detecting a change in resistance value of the defect detection portion.

[2] The honeycomb filter according to [1], wherein the conductive member is disposed on an inner surface and an outer surface of the honeycomb structure portion.

[3] The honeycomb filter according to [2], wherein the conductive member disposed inside the honeycomb structure portion is disposed inside the partition wall.

[4] The honeycomb filter according to [3], wherein the conductive member is arranged in parallel with the axial direction at a portion where the partition walls intersect.

[5] A plurality of the conductive members are disposed in the honeycomb structure portion, and the conductive members disposed in the honeycomb structure portion are disposed on an outer surface of the honeycomb structure portion. The honeycomb filter according to any one of [2] to [4], which is connected by a conductive member.

[6] The honeycomb filter according to any one of [1] to [5], wherein the defect detection unit has an external terminal on an outer surface of the honeycomb structure unit.

[7] The honeycomb filter according to any one of [1] to [6], wherein the defect detection unit includes a plurality of the conductive members arranged electrically in parallel.

[8] The honeycomb filter according to any one of [1] to [7], wherein the defect detection unit changes a resistance value by cutting or deformation of the conductive member due to generation of a defect.

[9] The honeycomb filter according to any one of [1] to [8], wherein the defect location and / or the cause of the defect can be identified by detecting a change in the resistance value of the defect detection unit.

[10] The honeycomb filter according to any one of [1] to [9], wherein the material of the honeycomb structure part is ceramics.

[11] The honeycomb structure includes a predetermined cell in which one end is opened and the other end is plugged, and the one end is plugged and the other end is The honeycomb filter according to any one of [1] to [10], wherein the remaining cells that are opened are alternately arranged.

[12] A honeycomb having partition walls that form a plurality of cells penetrating in the axial direction by extruding a clay containing a forming raw material together with a conductive material, and a linear and / or strip-shaped conductive material A method for manufacturing a honeycomb filter, comprising: forming a formed body, firing the honeycomb formed body, and manufacturing a honeycomb filter including a honeycomb structure portion and a defect detection portion having a linear and / or strip-shaped conductive member.

[13] Extruding the forming raw material so that the conductive material is embedded in the partition walls of the honeycomb molded body, exposing the end of the conductive member on the surface of the honeycomb structure, The method for manufacturing a honeycomb filter according to [12], wherein the defect detection portion is manufactured by printing the conductive member on the outer surface of the honeycomb structure portion so as to connect the end portions of the conductive member.

  According to the honeycomb filter of the present invention, the honeycomb structure includes a defect detection unit having linear and / or strip-shaped conductive members disposed in the honeycomb structure unit, and detects a change in the resistance value of the defect detection unit. It is possible to detect a defect in a part, that is, a defect in the honeycomb filter, so that the defect location and the cause of the defect can be detected without arranging a device for detecting the defect in the honeycomb filter on the downstream side of the honeycomb filter. Is possible. And according to the manufacturing method of the honey-comb filter of this invention, it is possible to manufacture such a honey-comb filter of this invention efficiently.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings.However, the present invention is not limited to the following embodiments and is within the scope of the present invention. It should be understood that design changes, improvements, and the like can be made as appropriate based on ordinary knowledge of those skilled in the art.

  FIG. 1 schematically shows an embodiment of a honeycomb filter of the present invention, FIG. 1 (a) is a perspective view, and FIG. 1 (b) is a front view as viewed from one end in an axial direction P. FIG.1 (c) is AA 'sectional drawing of FIG.1 (b).

  As shown in FIGS. 1 (a) to 1 (c), a honeycomb filter 100 of the present embodiment includes a honeycomb structure portion 1 having partition walls 2 that partition a plurality of cells 3 penetrating in the axial direction P, and a honeycomb structure. And a defect detection unit 7 having linear and / or strip-like conductive members 4 and 5 disposed in the structure unit 1. And it is a honeycomb filter which can detect the defect of the honeycomb structure part 1, ie, the defect of the honeycomb filter 100, by detecting the change of the resistance value of the defect detection part 7. FIG. In FIG. 1A, the conductive member 4 disposed inside the honeycomb structure 1 and the conductive member 5b disposed on the outer surface on the other end 1b side of the honeycomb structure 1 are shown. Is shown by a broken line, but for the cell 3, only the opening portion on the one end 1a side of the honeycomb structure portion 1 is shown, and a space portion that penetrates the inside of the honeycomb structure portion 1 (a portion that is hidden and cannot be seen) ) Is omitted. Further, regarding the distinction between “linear” and “strip” in the conductive members 4 and 5, the value of “width (major axis) / thickness (minor axis)” in the cross-sectional shape perpendicular to the length direction is A case of 2 or more is defined as a strip shape, and a case of less than 2 is defined as a linear shape.

  As described above, since the linear and / or strip-shaped conductive members 4 and 5 are disposed in the honeycomb structure portion 1, when a defect occurs in the honeycomb structure portion 1, the conductive property disposed at the position of the defect. The members 4 and 5 are also defective. And the resistance value of the defect detection part 7 changes with the defects of the conductive members 4 and 5, and it becomes possible to detect the defect of the honeycomb filter 100 by detecting the change of the resistance value. For example, when a crack occurs in the honeycomb structure 1, the conductive members 4 and 5 disposed at the position where the crack occurs also affect the crack. For this reason, the conductive members 4 and 5 are disconnected (cut), deformed (including a case where a part thereof is broken), and the resistance value of the defect detection unit 7 changes, and the change in the resistance value is detected. By doing so, it becomes possible to detect a defect of the honeycomb filter 100. That is, in the honeycomb filter 100 of the present embodiment, the resistance value of the defect detection unit 7 changes due to cutting or deformation (including partial breakage) of the conductive members 4 and 5 due to the occurrence of the defect. By detecting the change, it becomes possible to detect the defect and to specify the defect location and the cause of the defect.

  In the honeycomb filter 100 of the present embodiment, the defect detection unit 7 is disposed on the conductive member (internal wiring) 4 disposed inside the partition wall 2 and on the outer surface (both end surfaces) of the honeycomb structure unit 1. And an external terminal for applying a voltage to the outer surface of the honeycomb structure portion 1. The external terminals are provided with pads 6 and 6 for wiring with the outside, and a voltage is applied to the defect detection unit 7 through the pads 6 and 6 to measure the resistance of the defect detection unit 7. Is made possible. Although the internal wiring 4 is disposed inside the partition wall 2, it may be disposed inside the honeycomb structure portion 1. The inside of the honeycomb structure portion 1 refers to the inside of the partition wall, the surface of the partition wall (the inner surface of the cell 3), and the space portion of the cell 3. Further, the outer surface of the honeycomb structure portion 1 refers to both end surfaces and side surfaces of the honeycomb structure portion 1.

  In the honeycomb filter 100 of the present embodiment, the conductive member (internal wiring) 4 of the defect detection unit 7 is preferably disposed at a position where a defect such as a crack is likely to occur, and a defect such as a crack is generated in advance. It is preferable to specify a position where it is easy to do, and to arrange the internal wiring 4 at that position. For example, as shown in FIG. 1A, it is preferable that the partition walls 2 are arranged so as to be parallel to the axial direction (center axis direction) P at the intersections. Here, “parallel” includes not only a case where the internal wiring 4 and the axial direction P are completely parallel, but also a state where the angle is within a range of about 15 °. When the honeycomb filter 100 is used, a defect such as a crack is likely to occur at a portion where the partition walls 2 intersect. Therefore, the defect can be effectively detected by arranging the internal wiring 4 at this position. Become. The position where the internal wiring 4 is disposed may not be a portion where the partition wall 2 intersects but may be the surface of the partition wall 2. Further, when the internal wiring 4 is arranged at a portion where the partition walls 2 intersect, the arrangement position is not limited to the position shown in FIG. 1A, and may be arranged at another position. A smaller number may be used.

  In the honeycomb filter 100 of the present embodiment, as shown in FIGS. 1A to 1C, a plurality of conductive members (internal wirings) 4 are arranged inside the honeycomb structure 1, and the honeycomb structure It is preferable that the conductive member (internal wiring) 4 disposed inside 1 is connected by a conductive member (external wiring) 5 disposed on the outer surface of the honeycomb structure portion 1. In the present embodiment, a plurality of internal wirings 4 arranged in parallel in the axial direction P are connected to the external wiring 5a disposed at one end 1a of the honeycomb structure 1 and the other end 1b of the honeycomb structure 1. Are connected to each other by external wiring 5b. By forming in this way, after arranging the internal wiring 4 in the honeycomb structure portion 1, it is possible to form the external wiring 5 by printing or the like and easily connect the internal wiring 4 and the external wiring 5 to each other. Become.

  In the honeycomb filter 100 of the present embodiment, as shown in FIG. 1A, both ends of an internal wiring 4 and an external wiring 5 formed as a single wiring are connected to the outside of the honeycomb structure 1. External terminals are exposed on the surface. The pads 6 and 6 are connected to the external terminals.

  The width and thickness of the internal wiring 4 and the external wiring 5 are not particularly limited, but are the thickness and width at which defects such as cutting and deformation occur simultaneously when a defect occurs in the honeycomb filter 100. It is preferable. Therefore, it is not preferable that the thickness is too large or the width is too wide because it is difficult to detect a defect. Further, the internal wiring 4 and the external wiring 5 are not preferable because it is difficult to detect a defect even if the mechanical strength is too strong. Further, when the honeycomb filter 100 vibrates or the like, the internal wiring 4 and the external wiring 5 say that “the honeycomb filter 100 is not defective but the internal wiring 4 and the external wiring 5 are disconnected”. It is preferable to have a thickness and a width such that there is no gap. Therefore, being too thin or too narrow is not preferable in that it may be recognized that a defect has occurred even though the honeycomb filter has no defect. The internal wiring 4 is preferably a straight line, but may include a bent portion. The internal wiring 4 is preferably constant in thickness, but may have a non-constant portion.

  The materials of the internal wiring 4, the external wiring 5, and the pad 6 are not particularly limited, but are preferably made of a conductive metal that is solid at room temperature. For example, simple metals or alloys containing aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, etc. Can be mentioned. The internal wiring 4 may be a powdered metal or a paste containing metal hardened by baking or the like, or a metal wire may be used. The external wiring 5 is preferably formed by printing or the like, but may be a paste obtained by applying a paste containing powdered metal to the outer surface of the honeycomb structure portion 1 and solidifying by firing or a metal wire. Good. The pad 6 is preferably formed by printing or the like, but may be one obtained by applying a paste containing a powdered metal to the outer surface of the honeycomb structure portion 1 and hardening it by firing or the like.

  As shown in FIGS. 1A to 1C and 2, in the honeycomb filter 100 of the present embodiment, the defect detection unit 7 is formed by connecting the internal wiring 4 and the external wiring 5. Both ends (external terminals) of the book wiring are connected to the pads 6 and 6. FIG. 2 is a perspective view schematically showing only the defect detection unit 7 disposed in the honeycomb filter 100 of the present embodiment. On the other hand, in another embodiment of the honeycomb filter of the present invention, as shown in FIG. 3, the defect detection unit 7 constituting the honeycomb filter is electrically connected in parallel with two conductive members ( The first parallel wiring 11a and the second parallel wiring 11b) are provided. Here, each of the plurality of conductive members arranged electrically in parallel is referred to as “parallel wiring”. In the present embodiment, there are two conductive members (parallel wirings), but three or more conductive members may be used. As described above, when the defect detection unit 7 includes a plurality of electrically conductive members (a plurality of parallel wirings) arranged in parallel, when the conductive member is cut or the like, the disconnection is prevented. The generated parallel wiring can be specified, and thereby the defective portion can be specified. Even when the defect detection unit 7 is a single wiring, it is possible to identify the defect location by setting the position where the wiring is arranged to a specific position in the honeycomb filter. In the case of this arrangement, it is possible to specify the defect portion over a wider range. Here, FIG. 3 is a perspective view schematically showing only the defect detection unit arranged in another embodiment of the honeycomb filter of the present invention.

  As described above, according to the honeycomb filter of the present invention, it is possible to specify a place where a defect occurs (defect portion), but it is also possible to specify the cause of the defect (defect cause) at the same time. “When the conductive member is completely cut”, “When the conductive member is deformed (including partial breakage)”, “The conductive member is cut or deformed, but due to vibration of the honeycomb filter, etc. There are various states of defect occurrence, such as when the separated part comes into contact with or leaves, and the way the resistance changes depends on the state of the defect. It becomes possible to specify what kind of defect has occurred (defect state). Here, the term “defect cause” refers to the state of a defect that has occurred.

  In one embodiment of the honeycomb filter of the present invention, the material of the honeycomb structure portion 1 is preferably ceramics, and alumina, magnesium oxide, silicon oxide, silicon nitride, aluminum nitride, zirconia, cordierite, mullite, spinel, magnesium -More preferably, it contains at least one selected from the group consisting of calcium-titanium-based oxides, barium-titanium-zinc-based oxides, and barium-titanium-based oxides.

  The honeycomb structure portion includes a predetermined cell in which one end is opened and the other end is plugged, and a remaining cell in which one end is plugged and the other end is opened. Are preferably arranged alternately. In this case, at both ends, the cell opening and the plugged portion are arranged so as to form a checkered pattern. Thereby, particulate matter can be efficiently collected as DPF.

  The size of the honeycomb structure part is not particularly limited and can be appropriately selected depending on the application such as DPF. There is no restriction | limiting in particular about the thickness of the partition of a honeycomb structure part, According to uses, such as DPF, it can select suitably. There is no restriction | limiting in particular about the cell density and cell number of a honeycomb structure part, According to uses, such as DPF, it can select suitably.

  In the honeycomb filter of the present embodiment, the shape of the cross section perpendicular to the central axis of the honeycomb structure portion 1 may be a quadrangle as shown in FIGS. 1 (a) and 1 (b). Other polygonal shapes such as a circular shape, an elliptical shape, and a track shape may be used. The cross-sectional shape perpendicular to the central axis of the cell 3 (perpendicular to the longitudinal direction) may be a quadrangle as shown in FIGS. 1A and 1B, but may be a pentagon, a hexagon, or the like. Other polygons may be used, and other shapes such as a circle, an ellipse, and a track shape may be used.

  Next, an embodiment of a method for manufacturing a honeycomb filter of the present invention will be described.

  In one embodiment of the method for manufacturing a honeycomb filter of the present invention, first, a clay containing a forming raw material is produced. This is to use the raw materials listed above as the material for the honeycomb structure 1, and mix and knead the raw materials to form a clay. For example, a dispersion medium such as water, an organic binder, a dispersant and the like are added to a powder material such as ceramics to form a molding material, which is kneaded to form a clay-like clay.

  As the organic binder, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol and the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  As the dispersant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  There is no restriction | limiting in particular as a method of knead | mixing a shaping | molding raw material and preparing a clay, For example, the method of using a kneader, a vacuum clay kneader, etc. can be mentioned.

  Next, the obtained clay is extruded together with a conductive material to form a honeycomb molded body having partition walls that form a plurality of cells penetrating in the axial direction and linear and / or strip-shaped conductive materials. Make it. As a result, a honeycomb molded body having a structure including the honeycomb structure portion 1 and the conductive member (internal wiring) 4 among the structures of the honeycomb filter 100 shown in FIGS. 1A to 1C can be obtained. The method of extruding the clay together with the conductive material is not particularly limited. For example, as shown in FIGS. 4 (a) and 4 (b), the back hole 22 of the die 21 for forming a honeycomb shape is used. It is preferable to dispose the conductive material supply pipe 24 for supplying the conductive material 32 and to extrude the clay 31 and simultaneously supply the conductive material 32 from the conductive material supply pipe 24. At this time, the tip of the conductive material supply pipe 24 (the portion from which the conductive material 32 is discharged) is placed at the center of the portion where the slits 23 intersect as shown in FIGS. 4 (a) and 4 (b). It is preferable to position. As a result, the conductive material can be embedded in the partition walls of the honeycomb molded body, and the conductive member can be disposed in parallel with the axial direction at the intersection of the partition walls. become. The shape and size of the die 21 can be appropriately determined according to the structure of the honeycomb formed body to be produced. As the conductive material 32, the metal powder mentioned as the material of the conductive member (internal wiring, external wiring) and the pad in one embodiment of the honeycomb filter of the present invention is mixed with water, alcohol, organic binder or the like. The pasty material etc. which were made can be mentioned. It is preferable to adjust the supply amount (speed) of the conductive material 32 according to the extrusion amount (speed) of the clay 31 so that a conductive member having a desired thickness is formed. Here, FIG. 4A schematically shows a part of the base on which the conductive material supply pipe 24 is arranged, and is a surface of the base (a surface on which the clay is discharged), and a slit is formed. FIG. FIG. 4B is a cross-sectional view taken along the line B-B ′ of FIG. FIG. 4B shows the base 21 and the conductive material supply pipe 24. As a method of forming the conductive material so as to extend in a direction perpendicular to the axial direction, a mask is applied to one end face of the honeycomb filter except for a portion where wiring is desired, and then immersed in a conductive paste solution. There is a method of baking after drying and removing the mask. There is also a method in which a pattern is printed with a conductive paste on the end portion using a screen printing method and then fired. Further, there is a method in which the end portion is dipped in a conductive paste solution and then dried, and an unnecessary portion is removed by a laser trimming method and then fired.

  Next, the obtained honeycomb formed body is fired to produce a honeycomb filter including a honeycomb structure portion and a defect detection portion having a linear and / or strip-like conductive member (internal wiring). The firing conditions (temperature and time) are not particularly limited, and differ depending on the type of the forming raw material. Prior to firing, the honeycomb formed body may be dried. The drying method is not particularly limited, and conventionally known drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying and the like can be used. Especially, the drying method which combined hot air drying, microwave drying, or dielectric drying is preferable at the point which can dry the whole molded object rapidly and uniformly. Further, after drying and before firing, the honeycomb formed body may be calcined to burn and remove organic substances (organic binder, dispersant, etc.) in the honeycomb formed body.

  Next, a linear and / or strip-shaped conductive member (external wiring) is arranged on the outer surface of the honeycomb structure portion of the honeycomb filter obtained by firing so as to be connected to the internal wiring to detect defects. It is preferable to form a part. As shown in FIGS. 1A to 1C, the external wiring is preferably disposed on both end faces of the honeycomb structure portion 1. The external wiring is preferably formed by printing on the outer surface such as the end face of the honeycomb structure portion. Thus, in order to connect the external wiring to the internal wiring, it is preferable that the end of the internal wiring to be connected to the external wiring is exposed on the outer surface of the honeycomb structure portion. As a method of exposing the internal wiring to the outer surface of the honeycomb structure portion, the end of the internal wiring may be exposed when the honeycomb formed body is extruded, or when the honeycomb formed body is extruded. Then, although not exposed, after forming the honeycomb formed body, the end portion of the internal wiring may be exposed by grinding the end face or the like. And it is preferable to print a pad so that it may connect with the external terminal exposed to the outer surface of a honeycomb structure part. Examples of the material for the pad include the metals mentioned as the material for the pad in the embodiment of the honeycomb filter of the present invention. Thereby, one embodiment of the honeycomb filter of the present invention as shown in FIGS. 1A to 1C can be obtained.

  Next, it is preferable to form plugging portions at the end portions of the respective cells so as to form a checkered pattern on both end faces of the honeycomb filter. As a method for forming the plugging portion, first, a plugging slurry (or plugging paste) containing powder such as a ceramic raw material used for manufacturing the honeycomb formed body, water or alcohol, and an organic binder is used. Is stored in a storage container. Then, one end face of the honeycomb filter is masked in a checkered pattern by alternately closing the cell openings. The end portion on the side subjected to the mask is immersed in a storage container, and the plugging slurry is filled into the opening of the cell not subjected to the mask to form a plugging portion. For the other end, a mask is applied to the cells plugged at one end, and the plugged portion is formed in the same manner as the plugged portion is formed at the one end. As a result, the cells not plugged at the one end are plugged at the other end, and the cells are alternately closed in a checkered pattern at the other end. Note that the plugging portion may be disposed on the honeycomb formed body before the external wiring is disposed. Further, the plugged portion may be formed before firing the honeycomb formed body, or the plugged portion may be formed after firing.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for immediately detecting the occurrence of a DPF defect and recognizing an apparatus abnormality, thereby contributing to the prevention of air pollution.

Fig. 1 (a) is a perspective view, Fig. 1 (b) is a front view seen from one end in the axial direction P, and schematically shows an embodiment of a honeycomb filter of the present invention. FIG. 2C is a cross-sectional view taken along the line AA ′ of FIG. It is the perspective view which showed typically only the defect detection part 7 arrange | positioned at the honey-comb filter 100 of this embodiment. It is the perspective view which showed typically only the defect detection part arrange | positioned in other embodiment of the honey-comb filter of this invention. FIG. 4A schematically shows a part of the base on which the conductive material supply pipe is arranged, and is a plan view seen from the surface side of the base. FIG. 4B is a plan view of FIG. It is BB 'sectional drawing.

Explanation of symbols

1: honeycomb structure, 1a: one end, 1b: the other end, 2: partition, 3: cell, 4: conductive member (internal wiring), 5: conductive member (external wiring), 5a, External wiring disposed at one end, 5b: external wiring disposed at the other end, 6: pad, 7: defect detection unit, 11a: first parallel wiring, 11b: second parallel Wiring, 21: base, 22: back hole, 23: slit, 24: conductive material supply unit, 31: clay, 32: conductive material, 100: honeycomb filter, P: axial direction.

Claims (13)

A honeycomb structure part having partition walls for partitioning a plurality of cells penetrating in the axial direction;
A defect detection unit having a linear and / or strip-shaped conductive member disposed in the honeycomb structure unit,
A honeycomb filter capable of detecting a defect in the honeycomb structure portion by detecting a change in a resistance value of the defect detection portion.   The honeycomb filter according to claim 1, wherein the conductive member is disposed on an inner surface and an outer surface of the honeycomb structure portion.   The honeycomb filter according to claim 2, wherein the conductive member disposed in the honeycomb structure portion is disposed in the partition wall.   The honeycomb filter according to claim 3, wherein the conductive member is disposed at a portion where the partition walls intersect with each other so as to be parallel to the axial direction.   A plurality of the conductive members are arranged inside the honeycomb structure part, and the conductive members arranged inside the honeycomb structure part are arranged on the outer surface of the honeycomb structure part. The honey-comb filter in any one of Claims 2-4 connected by these.   The honeycomb filter according to any one of claims 1 to 5, wherein the defect detection unit has an external terminal on an outer surface of the honeycomb structure unit.   The honeycomb filter according to any one of claims 1 to 6, wherein the defect detection unit includes a plurality of the conductive members arranged electrically in parallel.   The honeycomb filter according to any one of claims 1 to 7, wherein the defect detection unit changes a resistance value by cutting or deformation of the conductive member accompanying the occurrence of a defect.   The honeycomb filter according to any one of claims 1 to 8, wherein a defect location and / or a cause of a defect can be specified by detecting a change in a resistance value of the defect detection unit.   The honeycomb filter according to any one of claims 1 to 9, wherein a material of the honeycomb structure part is ceramics.   The honeycomb structure has a predetermined cell in which one end is opened and the other end is plugged, and the one end is plugged and the other end is opened. The honeycomb filter according to any one of claims 1 to 10, wherein the remaining cells are alternately arranged. A honeycomb molded body having a partition wall formed by extruding a clay containing a forming raw material together with a conductive material to partition a plurality of cells penetrating in the axial direction, and a linear and / or strip-shaped conductive material. Made,
A method for manufacturing a honeycomb filter, comprising: firing the honeycomb formed body to produce a honeycomb filter including a honeycomb structure portion and a defect detection portion having a linear and / or strip-like conductive member. As the conductive material is embedded in the partition walls of the honeycomb molded body, the molding raw material is extruded,
An end portion of the conductive member is exposed on the surface of the honeycomb structure portion, and the conductive member is printed on the outer surface of the honeycomb structure portion so as to connect the end portions of the conductive member. The method for manufacturing a honeycomb filter according to claim 12 to be manufactured.

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