Manufacturing method of honeycomb structure

Abstract

To provide a method of manufacturing a honeycomb structure in which a plurality of honeycomb segments are assembled, and which can prevent positional deviation of an electric heating wire.SOLUTION: The method of manufacturing a honeycomb structure includes: a honeycomb assembly manufacturing step of manufacturing a honeycomb assembly by bonding a plurality of honeycomb segments having partition walls that partition and form a plurality of cells with side surfaces of the respective honeycomb segments arranged in a row so that the side surfaces are opposed to each other; an electric heating wire arrangement step of fixing and arranging an electric heating wire on a main surface of the honeycomb assembly which is a surface where the side surfaces of the respective honeycomb segments constituting the honeycomb assembly are arranged in a row; an adhesive application step of applying an adhesive over the electric heating wire fixed to the main surface of the honeycomb assembly; and an adhesion step of arranging the electric heating wire, laminating the main surface of the honeycomb assembly having the adhesive applied thereon and a main surface of another honeycomb assembly, and bonding the honeycomb assemblies to each other with the adhesive.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a honeycomb structure. [Background technology]

[0002] In order to purify harmful substances contained in exhaust gas emitted from an engine, an exhaust gas purification device equipped with a honeycomb substrate carrying a catalyst capable of purifying exhaust gas is installed in the exhaust pipe route. In order to improve the efficiency of purifying harmful substances by an exhaust gas purification device, it is necessary to maintain the temperature inside the exhaust gas purification device at a temperature suitable for catalyst activation (hereinafter also referred to as catalyst activation temperature).

[0003] Patent Document 1 discloses a filter that collects soot contained in the exhaust gas of a diesel engine to purify the exhaust gas. In this filter, an electric heating wire is disposed as a heating element between adjacent filters to burn the soot accumulated inside the filter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-54643 Summary of the Invention [Problem to be solved by the invention]

[0005] In the configuration disclosed in Patent Document 1, a heating wire is arranged for each honeycomb segment, and an electrode terminal is provided for each honeycomb segment. However, this structure makes the current path from the power supply part complicated, so it has been desired to have a structure in which the heating wires and electrode terminals are consolidated.

[0006] Therefore, the inventors attempted to consolidate the heating wires and electrode terminals by creating a honeycomb assembly by combining honeycomb segments and arranging the heating wires between the honeycomb assemblies, rather than arranging a heating wire for each honeycomb segment. However, when the honeycomb assemblies are bonded together by disposing the heating wire and adhesive between them, the position of the heating wire within the adhesive layer may deviate from the design. Furthermore, if the position of the heating wire deviates from the design, there is a problem in that the temperature of the honeycomb segments varies greatly.

[0007] The present invention has been made to solve the above problems, and aims to provide a method for manufacturing a honeycomb structure in which a plurality of honeycomb segments are combined, and which can prevent misalignment of the heating wire. [Means for solving the problem]

[0008] The method for manufacturing a honeycomb structure of the present invention includes a honeycomb aggregate manufacturing step of manufacturing a honeycomb aggregate by arranging a plurality of honeycomb segments, each having partition walls that define a large number of cells, in a line so that side surfaces of the honeycomb segments face each other and bonding the honeycomb segments together; a heating wire arranging step of fixing and arranging a heating wire on a main surface of the honeycomb aggregate, which is a surface where side surfaces of each honeycomb segment constituting the honeycomb aggregate are aligned; an adhesive applying step of applying an adhesive onto the heating wire fixed to the main surface of the honeycomb aggregate; a bonding step of placing the heating wire on the main surface of the honeycomb aggregate to which the adhesive has been applied and placing the main surface of another honeycomb aggregate on top of the main surface of the honeycomb aggregate, and bonding the honeycomb aggregates together with the adhesive; The method is characterized by carrying out the following.

[0009] In the method for manufacturing a honeycomb structure of the present invention, the heating wire is fixed to the main surface of the honeycomb aggregate, and then an adhesive is applied to bond the honeycomb aggregate to another honeycomb aggregate. Since the heating wires are fixed to the main surfaces of the honeycomb aggregate before the bonding step is performed, the positional displacement of the heating wires is prevented during the bonding step.

[0010] In the method for manufacturing a honeycomb structure of the present invention, the heating wires are preferably fixed with an organic fixing agent, an inorganic fixing agent or a tape in the heating wire arranging step. These materials allow the heating wires to be fixed to the main surfaces of the honeycomb aggregate, preventing the heating wires from shifting in position during the bonding process.

[0011] In the manufacturing method of the honeycomb structure of the present invention, in the heating wire arrangement process, it is preferable that a plurality of electrode terminals to which both ends of the heating wire are connected are fixed and arranged on the main surface of the honeycomb aggregate on which the heating wire is fixed and arranged. By connecting the heating wires to the electrode terminals in advance, and then fixing the electrode terminals to the main surfaces of the honeycomb aggregate and then applying adhesive, it is possible to prevent the electrode terminals from shifting in position during the bonding process, and also to prevent the heating wires connected to the electrode terminals from shifting in position.

[0012] It is preferable that a plurality of heating wires are connected in parallel between the electrode terminals.

[0013] In the method for manufacturing a honeycomb structure of the present invention, it is preferable to carry out a degreasing step of degreasing the adhesive placed between the main surfaces of the honeycomb aggregated bodies. In the degreasing step, it is preferable to burn off the material used to fix the heating wire to the main surface of the honeycomb aggregate. The degreasing process solidifies the adhesive, allowing the honeycomb assemblies to be bonded together. After the adhesive has solidified, the position of the heating wire is fixed within the adhesive layer, so it is acceptable to burn off the material used to fix the heating wire in the heating wire placement process. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view schematically showing an example of a honeycomb structure of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a honeycomb segment in a direction perpendicular to the longitudinal direction. [Figure 3] FIG. 3 is a partial cross-sectional view of the honeycomb structure shown in FIG. [Figure 4] FIG. 4 is a perspective view schematically showing an example of a honeycomb aggregate. [Figure 5] FIG. 5 is a perspective view schematically showing a heating wire assembly used in the heating wire arrangement step. [Figure 6] FIG. 6 is a perspective view that schematically shows an example in which heating wires are fixed to the main surfaces of the honeycomb aggregated body in the heating wire arranging step. [Figure 7] FIG. 7 is a perspective view that schematically shows an example in which an adhesive is applied from above the heating wire fixed to the main surface of the honeycomb aggregated body in the adhesive application step. [Figure 8] FIG. 8 is a perspective view schematically showing the initial bonding in the bonding process. [Figure 9] FIG. 9 is a perspective view schematically showing a step of applying vibration to the main surface of the honeycomb aggregate with heating wires in the bonding step. [Figure 10] FIG. 10 is a perspective view schematically showing the second bonding in the bonding step. [Figure 11] FIG. 11 is a perspective view schematically showing an example of a laminate with heating wires. [Figure 12] FIG. 12 is a perspective view schematically showing steps of another embodiment of the method for manufacturing a honeycomb structure of the present invention. [Figure 13] FIG. 13 is a perspective view schematically showing steps of another embodiment of the method for manufacturing a honeycomb structure of the present invention. [Figure 14] FIG. 14 is a perspective view schematically showing steps of another embodiment of the method for manufacturing a honeycomb structure of the present invention. [Figure 15] FIG. 15 is a perspective view schematically showing steps of another embodiment of the method for manufacturing a honeycomb structure of the present invention.

[0015] (Detailed Description of the Invention) [Honeycomb structure] A method for manufacturing a honeycomb structure of the present invention will be described below. The method for manufacturing a honeycomb structure of the present invention is characterized by carrying out the following steps: a honeycomb aggregate manufacturing process, in which a plurality of honeycomb segments, each having partition walls that define a large number of cells, are lined up in a row with the side surfaces of each honeycomb segment facing each other and bonded together to form a honeycomb aggregate; a heating wire arrangement process, in which an electric heating wire is fixed and arranged on the main surface of the honeycomb aggregate, which is the surface along which the side surfaces of each honeycomb segment that constitutes the honeycomb aggregate are lined up in a row; an adhesive application process, in which an adhesive is applied onto the electric heating wire fixed on the main surface of the honeycomb aggregate; and a bonding process, in which the main surface of the honeycomb aggregate on which the electric heating wire has been arranged and the adhesive has been applied is overlapped with the main surface of another honeycomb aggregate, and the honeycomb aggregates are bonded together with the adhesive.

[0016] First, a honeycomb structure manufactured by the method for manufacturing a honeycomb structure of the present invention will be described. FIG. 1 is a perspective view schematically showing an example of a honeycomb structure of the present invention. The honeycomb structure 1 shown in Figure 1 is made up of a combination of multiple honeycomb segments 20 each having partition walls 22 that define a large number of cells 21, and has a first end face 11 through which gas flows in and a second end face 12 through which gas flows out. The direction in which the cells 21 of the honeycomb segment 20 extend is defined as the longitudinal direction (the direction indicated by the double-headed arrow L in FIG. 1). The honeycomb segments are joined together via an adhesive layer 30 . In addition, an electrode terminal 40 protrudes from the first end face 11 .

[0017] The material for forming the honeycomb segments (partition walls) is preferably one with high thermal conductivity, such as SiC or Si-impregnated SiC.

[0018] The thickness of the partition walls is preferably uniform. Specifically, the thickness of the partition walls is preferably less than 0.30 mm. Also, the thickness is preferably 0.05 mm or more.

[0019] The shape of the cells is not limited to a quadrangular prism, but may be a triangular prism, a hexagonal prism, or the like. The cells may have different shapes, but are preferably all the same, that is, in a cross section perpendicular to the longitudinal direction of the honeycomb segment, the size of the cells surrounded by the partition walls is preferably the same.

[0020] The porosity of the partition walls is preferably 50% or less. When the porosity of the partition walls is 50% or less, it is possible to achieve both high mechanical strength and exhaust gas purification performance.

[0021] If the porosity of the partition walls exceeds 50%, the porosity becomes too high, which reduces the mechanical properties of the honeycomb segments, making the honeycomb structure more susceptible to cracks, breakage, and the like during use.

[0022] The shape of the honeycomb structure is not particularly limited, and examples thereof include not only a cylindrical shape but also a rectangular pillar shape, an elliptical pillar shape, an oblong pillar shape, a rectangular pillar shape with rounded edges (for example, a triangular pillar shape with rounded edges), etc.

[0023] When the honeycomb structure has a cylindrical shape, the ratio of the length in the longitudinal direction of the honeycomb structure to the diameter of the end face of the honeycomb structure (length / diameter) is preferably 0.8 or less.

[0024] The length of the honeycomb structure in the longitudinal direction is preferably 150 mm or less, and more preferably 50 mm or more.

[0025] FIG. 2 is a cross-sectional view of a honeycomb segment in a direction perpendicular to the longitudinal direction. When exhaust gas (the flow of exhaust gas is indicated by arrow G in FIG. 2) emitted from an internal combustion engine reaches the honeycomb segment 20, the exhaust gas flows into the cells 21 from the first end face 11 of the honeycomb segment 20. Furthermore, the exhaust gas passes through the cells 21 while coming into contact with the catalyst 23 supported on the partition walls 22. At this time, CO, HC, NO in the exhaust gas are dissolved in the XHarmful gas components such as these are purified by the catalyst 23 carried on the partition walls 22. Then, the exhaust gas flows out of the cells 21 at the second end face 12 of the honeycomb segment 20.

[0026] The catalyst 23 is not particularly limited as long as it can treat exhaust gas, and examples thereof include catalysts made of precious metals such as platinum, palladium, and rhodium, zeolite, titania, vanadium oxide, etc. The zeolite may be a CHA-type zeolite, and the zeolite may be ion-exchanged with Cu or the like. These catalysts may be used alone or in combination of two or more. When these catalysts are supported, CO, HC, NO X The present invention can effectively purify toxic exhaust gases such as toluene, ... In particular, it is preferable to use the honeycomb structure as an SCR catalyst that reduces NOx using zeolite as a catalyst.

[0027] FIG. 3 is a partial cross-sectional view of the honeycomb structure shown in FIG. A heating wire 50 is disposed between adjacent honeycomb segments 20. Electrode terminals 40 are provided on both ends of the heating wire 50, and the electrode terminals 40 protrude from the first end face 11. The heating wire 50 is disposed inside the adhesive layer 30 .

[0028] The material of the heating wire may be a nickel-chromium alloy, a nickel-chromium-iron alloy, a chromium-iron-aluminum alloy, etc. The heating wire may be in the form of either a wire or a plate. When the heating wire is linear, its diameter is not particularly limited, but is preferably 0.1 to 1 mm. When the heating wire is plate-shaped, its thickness is not particularly limited, but is preferably 0.1 to 0.5 mm, and its width is preferably 1 to 10 mm.

[0029] The adhesive layer is formed by applying and drying an adhesive paste containing an inorganic binder and inorganic particles, and may further contain inorganic fibers and / or whiskers. The thickness of the adhesive layer is preferably 0.5 to 3 mm.

[0030] Electrode terminals 40 are connected to both ends of the heating wire 50, and the electrode terminals 40 protrude from the first end face 11. Electricity can be supplied from the electrode terminals 40 to the heating wire 50 to cause the heating wire to generate heat. The electrode terminals 40 are plate-shaped and welded to the heating wire 50. The electrode terminals 40 are connected to each other by wiring that connects the electrode terminals.

[0031] 3 is a set of heating wires in which a plurality of heating wires (51, 52, 53) are connected in parallel. Electrode terminals 40 are connected to both ends of each heating wire. If the heating wire is a set of heating wires, even if one of the heating wires breaks, the set of heating wires will not break as a whole, so the deterioration of heating performance can be minimized.

[0032] A method for manufacturing a honeycomb structure of the present invention will be described below. In the example shown below, two sets of heating wires are arranged in each adhesive layer, and finally, two honeycomb structures are manufactured by cutting them in half at the center position in the longitudinal direction. (Honeycomb aggregate manufacturing process) In the honeycomb aggregate manufacturing process, a plurality of honeycomb segments each having partition walls that define a large number of cells are aligned in a row with their side surfaces facing each other and bonded together to manufacture a honeycomb aggregate.

[0033] The honeycomb segment can be manufactured by extruding a ceramic paste containing the material of the honeycomb segment, drying and firing the extruded ceramic paste. An adhesive paste is applied to the side surfaces of the honeycomb segments, and the honeycomb segments are lined up in a row with their side surfaces facing each other, and then dried to bond them together and produce a honeycomb assembly. The adhesive paste preferably contains an inorganic binder and inorganic particles.

[0034] FIG. 4 is a perspective view schematically showing an example of a honeycomb aggregate. The honeycomb aggregate 70 shown in FIG. 4 is made up of seven honeycomb segments 20 that are aligned in a row with their side surfaces facing each other and bonded together by an adhesive layer 30 . Taking into consideration the shape of the honeycomb structure to be manufactured, it is preferable to prepare a plurality of types of honeycomb aggregates each having a different number of honeycomb segments 20 included in one honeycomb aggregate 70. When manufacturing the cylindrical honeycomb structure shown in FIG. 1, two honeycomb aggregates each having five honeycomb segments and five honeycomb aggregates each having seven honeycomb segments are manufactured. 4 has two relatively wide main surfaces. The two main surfaces of the honeycomb aggregate 70 are referred to as a first main surface 71 and a second main surface 72.

[0035] (Heating wire placement process) In the heating wire arrangement step, heating wires are fixed and arranged on the main surface of the honeycomb aggregate, which is the surface where the side surfaces of the honeycomb segments constituting the honeycomb aggregate are aligned in a row.

[0036] The heating wire used in the method for manufacturing a honeycomb structure of the present invention is preferably a plurality of heating wires connected in parallel between electrode terminals. FIG. 5 is a perspective view schematically showing a heating wire assembly used in the heating wire arrangement step. In the heating wire assembly 50 shown in FIG. 5, a plurality of heating wires (heating wires 51, 52, 53) are connected in parallel between the electrode terminals 40. The heating wire assembly 50 can be produced by connecting both ends of each of the heating wires 51, 52, 53 to the electrode terminals 40 by means of welding or the like.

[0037] FIG. 6 is a perspective view that schematically shows an example in which heating wires are fixed to the main surfaces of the honeycomb aggregated body in the heating wire arranging step. As shown in Figure 6, a fixing agent 80 is applied to one of the main surfaces, namely the first main surface 71, of the honeycomb aggregate 70, and the heating wire assembly 50 is placed so that the fixing agent 80 comes into contact with each of the heating wires 51, 52, and 53, and the heating wire assembly 50 is fixed to the first main surface 71 of the honeycomb aggregate 70 by the fixing agent 80. By fixing the heating wire assembly 50 to the first main surface 71 of the honeycomb aggregate 70, a plurality of electrode terminals 40 are fixed and arranged on the main surface of the honeycomb aggregate 70. When fixing the heating wire assembly 50, the electrode terminal 40 may be fixed to the first main surface 71 of the honeycomb aggregate 70 with a fixing agent. The fixing strength of the heating wires with the fixing agent should be such that the positions of the heating wires and electrode terminals do not deviate from their designed positions when the honeycomb assembly bonding step described below is carried out. The fixing agent may be a material that is burned off during the subsequent drying process or by heating when the honeycomb structure is used.

[0038] In the heating wire arrangement step, the heating wire is preferably fixed using an organic fixing agent, an inorganic fixing agent, or tape. These materials allow the heating wires to be fixed to the main surfaces of the honeycomb aggregate, preventing the heating wires from shifting in position during the bonding process. Examples of organic fixing agents include organic adhesives whose main material is an organic substance, and include, but are not limited to, epoxy resin adhesives, polyvinyl acetate adhesives, nitrile rubber adhesives, phenol resin adhesives, vinyl acetate adhesives, chloroprene rubber adhesives, epoxy resin adhesives that harden by chemical reaction, acrylic resin adhesives, and silicone rubber adhesives.

[0039] Examples of inorganic fixing agents include inorganic adhesives whose main material is an inorganic substance, and although there are no particular limitations, they are preferably ceramic adhesives containing metal alkoxides or ceramic adhesives containing alumina sol or silica sol.

[0040] When an organic or inorganic fixing agent is used as the fixing agent, the organic or inorganic fixing agent is applied to the main surface of the honeycomb aggregate, and then a heating wire is placed on top of the agent, and the heating wire is fixed to the main surface of the honeycomb aggregate with the fixing agent in a manner as shown in Figure 6.

[0041] As the tape, a single-sided adhesive tape or a double-sided adhesive tape can be used, and a tape having the above-mentioned organic fixing agent or inorganic fixing agent applied to the surface of the substrate can be used. The base material of the tape is not particularly limited, but polypropylene resin, PET resin, polyimide resin, vinyl chloride resin, cloth, paper, etc. can be used.

[0042] When using a single-sided adhesive tape as the fixing agent, the heating wire is placed on the main surface of the honeycomb aggregate, and the single-sided adhesive tape is placed over the heating wire to fix the heating wire to the main surface of the honeycomb aggregate. When double-sided adhesive tape is used as the fixing agent, the double-sided adhesive tape is attached to the main surface of the honeycomb aggregate, and the release paper is peeled off to place the heating wire on the exposed adhesive surface, thereby fixing the heating wire to the main surface of the honeycomb aggregate.

[0043] In the heating wire arrangement step, spacers may be arranged on the main surface of the honeycomb aggregated body. Fig. 6 shows a spacer 81 arranged on the first main surface 71 of the honeycomb aggregated body. The spacer is a component provided to set the thickness of the adhesive layer formed in the bonding process to a predetermined thickness, and has enough strength to prevent it from being crushed when the main surfaces of the honeycomb aggregates are overlapped in the bonding process. In Figure 6, the spacer 81 is placed at the end of the first main surface 71 of the honeycomb aggregate, outside the electrode terminal 40, but the location where the spacer is placed is not limited, and the number and shape of the spacers are also not limited.

[0044] Furthermore, when spacers are provided, it is preferable that the thickness of the spacers is greater than the thickness of the heating wires and the thickness of the electrode terminals. If the thickness of the spacers is greater than the thickness of the heating wires and the thickness of the electrode terminals, the heating wires and the electrode terminals can be prevented from contacting the main surface of the opposing honeycomb aggregate (a honeycomb aggregate without a heating wire) when the honeycomb aggregates are stacked. This prevents the main surface of the mating honeycomb aggregate from being pressed by the hard heating wire and electrode terminal, thereby preventing damage to the mating honeycomb aggregate.

[0045] (Adhesive application process) In the adhesive application step, an adhesive is applied onto the heating wire fixed to the main surface of the honeycomb aggregate. FIG. 7 is a perspective view that schematically shows an example in which an adhesive is applied from above the heating wire fixed to the main surface of the honeycomb aggregated body in the adhesive application step. FIG. 7 shows how adhesive 90 is applied using a dispenser 91 onto the heating wire 50 fixed to the first main surface 71 of the honeycomb aggregate. The method for applying the adhesive is not particularly limited, and methods such as application with a dispenser, application with a bar coater, spray application, brush application, and roll coating can be used. As the adhesive, it is preferable to use the same adhesive paste as that used in producing the honeycomb aggregate. An adhesive 90 may be applied onto the electrode terminal 40 and the spacer 81 .

[0046] It is preferable to adjust the thickness of the adhesive so that the heating wires and electrode terminals are hidden. That is, it is preferable to make the thickness of the applied adhesive thicker than the thickness of the heating wires and the electrode terminals. It is also preferable to make the thickness of the applied adhesive thicker than the thickness of the spacers. This is because if the thickness of the adhesive is thinner than the thickness of the spacers, the adhesive will not come into contact with the opposing honeycomb aggregates when the honeycomb aggregates are stacked.

[0047] By carrying out the steps up to this point, a honeycomb aggregate 100 with heating wires is obtained, which is a honeycomb aggregate having heating wires arranged on the main surfaces of the honeycomb aggregate and further having adhesive applied thereto. The honeycomb aggregates 100 with heating wires are prepared in advance in the number required for producing the honeycomb structure.

[0048] (Adhesion process) In the bonding step, the main surface of a honeycomb aggregate to which an electric heating wire has been arranged and an adhesive has been applied is placed on the main surface of another honeycomb aggregate, and the honeycomb aggregates are bonded together with the adhesive. FIG. 8 is a perspective view schematically showing the initial bonding in the bonding process. In the first bonding, a honeycomb aggregate 70A without any heating wires is prepared, and one main surface of the honeycomb aggregate 70A, here the second main surface 72A, is placed facing upward. Separately, a honeycomb aggregate 100B with heating wire is prepared, and the first main surface 71B of the honeycomb aggregate 100B with heating wire, which is the main surface on which the heating wire 50 is arranged and the adhesive 90 is applied, is placed downward and overlapped with the second main surface 72A of the honeycomb aggregate 70A, and the honeycomb aggregate 70A and the honeycomb aggregate 100B with heating wire are bonded together with the adhesive 90. When the honeycomb aggregates to be stacked are different in size, the positions at which the heating wires, electrode terminals and adhesive are arranged are adjusted to the size of the smaller honeycomb aggregate. Specifically, the heating wires, electrode terminals and adhesive are provided up to the second honeycomb segment from the outside in the honeycomb aggregate 100B with heating wire, and the outermost honeycomb segment is not provided with the heating wires, electrode terminals and adhesive.

[0049] FIG. 9 is a perspective view schematically showing a step of applying vibration to the main surface of the honeycomb aggregate with heating wires in the bonding step. The second main surface 72B of the honeycomb aggregate 100B with heating wire faces upward, and no adhesive is applied to this surface. By contacting this surface with the vibration applying device 120 and applying pressure and vibration, the thickness of the adhesive 90 that bonds the honeycomb aggregate 70A and the honeycomb aggregate 100B with heating wire can be made uniform.

[0050] FIG. 10 is a perspective view schematically showing the second bonding in the bonding step. For the second bonding, a honeycomb aggregate 100C with heating wire is prepared, and the first main surface 71C of the honeycomb aggregate 100C with heating wire, which is the main surface on which the heating wire 50 is arranged and the adhesive 90 is applied, is placed downward and overlapped with the second main surface 72B of the honeycomb aggregate 100B with heating wire that was bonded in the first bonding, and the honeycomb aggregate 100B with heating wire and the honeycomb aggregate 100C with heating wire are bonded together with the adhesive 90. In this process, since the honeycomb assemblies to be stacked are the same size, the positions where the heating wires, electrode terminals and adhesive are arranged in the honeycomb aggregate 100C with heating wires are wider than those in the honeycomb aggregate 100B with heating wires. Specifically, the heating wires, electrode terminals and adhesive are provided up to the outermost honeycomb segments. After the honeycomb aggregate 100B with the heating wire and the honeycomb aggregate 100C with the heating wire are stacked, pressure and vibration are applied to the second main surface 72C of the honeycomb aggregate 100C with the heating wire as shown in FIG.

[0051] FIG. 11 is a perspective view schematically showing an example of a laminate with heating wires. The above steps are repeated to stack the required number of honeycomb assemblies with heating wire, and a laminate 110 with heating wire is obtained in which honeycomb assemblies with heating wire are stacked. The heating wire-equipped laminate 110 shown in FIG. 11 has the following configuration. One honeycomb assembly (honeycomb assembly 70A) with five honeycomb segments and no heating wires. Five honeycomb assemblies with heating wires, each having seven honeycomb segments and in which heating wires are arranged (honeycomb assemblies with heating wires 100B, 100C, 100D, 100E, and 100F: honeycomb assemblies with heating wires 100B have different heating wire arrangement positions). One honeycomb assembly with heating wires (100g honeycomb assembly with heating wires) with five honeycomb segments and heating wires.

[0052] The heating wire-equipped laminate 110 is heated to carry out a drying step in which the adhesive placed between the main surfaces of the honeycomb aggregate is dried. The drying step causes the adhesive to solidify and become an adhesive layer, which bonds the honeycomb aggregates together. The drying temperature and time can be appropriately set depending on the adhesive material.

[0053] After the adhesive has hardened through a drying process, the outer periphery of the laminate with heating wire may be processed to form a desired shape. Alternatively, after the outer periphery processing, a paste similar to the adhesive paste may be applied to the outer periphery of the laminate with heating wire to form a peripheral sealing material layer. Furthermore, after forming the peripheral sealing material layer, the laminate with the heating wire may be degreased to burn off the material used to fix the heating wire. If the material used to fix the heating wire is an organic fixing agent or tape, these materials will burn off when degreased at a temperature equal to or higher than the heat resistance temperature of the material. If the positions of the heating wire and the electrode terminals are fixed in the steps up to the degreasing step, the material used to fix the heating wire may be burned away in the degreasing step. By cutting the laminate with heating wires in half at the center position in the longitudinal direction after the drying process or degreasing process has been performed to solidify the adhesive, two honeycomb structures with electrode terminals exposed on the first end face can be produced. The electrode terminals are connected together so that the heating wire set is connected in parallel. Through the above steps, the honeycomb structure can be manufactured. In this step, heating wires are fixed to the main surfaces of the honeycomb aggregate, and then adhesive is applied to bond the honeycomb aggregate to other honeycomb aggregates. Since the heating wires are fixed to the main surfaces of the honeycomb aggregate before the bonding step is performed, the positional displacement of the heating wires is prevented during the bonding step.

[0054] The honeycomb structure can be used by connecting a power supply terminal to one end of the electrode terminal. It is also preferable to immerse the manufactured honeycomb structure in a slurry containing the catalyst and then dry it to support the catalyst on the partition walls of the honeycomb structure.

[0055] In addition, as another aspect of the manufacturing method of the honeycomb structure of the present invention, rather than producing the required number of honeycomb assemblies with heating wires and then performing the bonding process, the heating wire arrangement process, adhesive application process and bonding process may be repeated to obtain a laminate with heating wires. 12, 13, 14 and 15 are perspective views schematically showing steps of another embodiment of the method for manufacturing a honeycomb structure of the present invention.

[0056] FIG. 12 shows a schematic diagram of the first bonding step in the bonding process. FIG. 12 shows a honeycomb aggregate 200A with heating wires, which has five honeycomb segments and in which heating wires are arranged. In the first bonding, the first main surface 171A of the honeycomb aggregate 200A with heating wire, which is the main surface on which the heating wire is arranged and adhesive is applied, is faced upward and placed on the second main surface 172B of the honeycomb aggregate 170B on which the heating wire is not arranged, and the honeycomb aggregate 200A with heating wire and the honeycomb aggregate 170B are bonded together with adhesive 90.

[0057] As shown in FIG. 13, a vibration applying device 120 is brought into contact with a first main surface 171B of a honeycomb aggregate 170B to apply pressure and vibration.

[0058] FIG. 14 shows a schematic view of a state in which an electric heating wire is fixed and arranged on the first main surface 171B of the honeycomb aggregate 170B, and an adhesive 90 is applied onto the electric heating wire. Through this process, the honeycomb aggregate 170B becomes a honeycomb aggregate 200B with heating wires. That is, the heating wire arrangement step and adhesive application step are carried out while the honeycomb aggregates are being stacked.

[0059] FIG. 15 shows a schematic diagram of the second bonding step in the bonding process. In the second bonding, the second main surface 172C of the honeycomb aggregate 170C, which does not have heating wires, is placed on top of the first main surface 171B of the honeycomb aggregate 200B with heating wires, which is the main surface on which the heating wires are placed and adhesive 90 is applied, and the honeycomb aggregate 200B with heating wires and the honeycomb aggregate 170C are bonded together with adhesive 90. By repeating the above steps to bond the required number of honeycomb assemblies, fix the heating wires, and apply adhesive, a laminate 110 with heating wire, in which honeycomb assemblies with heating wires are stacked, can be obtained as shown in Fig. 11. A honeycomb structure can be manufactured by subjecting this laminate with heating wire to necessary steps such as drying, peripheral processing, forming a peripheral sealing material layer, degreasing, and cutting in half. In addition, it is preferable to immerse the manufactured honeycomb structure in a slurry containing a catalyst and dry it to load the catalyst on the partition walls of the honeycomb structure. In the above embodiment, a method for manufacturing two honeycomb structures was described in which two sets of heating wires were placed in each adhesive layer and then finally cut in half at the center position in the longitudinal direction, but it is also possible to manufacture a honeycomb structure by placing only one set of heating wires in each adhesive layer and not cutting it in half. [Explanation of symbols]

[0060] 1 Honeycomb structure 11 First end face of honeycomb structure 12 Second end face of honeycomb structure 20 honeycomb segments 21 cells 22 Bulkhead 23 Catalyst 30 Adhesive layer 40 electrode terminal 50 Heating wire (assembled heating wire) 51, 52, 53 heating wire 70, 70A honeycomb assembly 71, 71B, 71C First main surface of honeycomb assembly 72, 72A, 72B, 72C: Second main surface of honeycomb assembly 80 Fixative 81 Spacer 90 Adhesive 91 Dispenser 100, 100B, 100C, 100D, 100E, 100F, 100G Honeycomb assembly with heating wire 110 Laminated body with heating wire 120 Vibration device 170B, 170C Honeycomb aggregate 171A, 171B First main surface of honeycomb assembly 172B, 172C Second main surface of honeycomb assembly 200A, 200B Honeycomb assembly with heating wire

Claims

1. a honeycomb aggregate fabrication step of fabricating a honeycomb aggregate by arranging a plurality of honeycomb segments, each having partition walls that define a large number of cells, in a line with the side surfaces of the honeycomb segments facing each other and bonding them together; a heating wire arranging step of fixing and arranging a heating wire on a main surface of the honeycomb aggregate, which is a surface where side surfaces of each honeycomb segment constituting the honeycomb aggregate are aligned, with a fixing strength that does not deviate from a designed position; an adhesive application step of applying an adhesive onto the heating wire fixed to the main surface of the honeycomb aggregate; a bonding step of placing the heating wire on the main surface of the honeycomb aggregate to which the adhesive has been applied and placing a main surface of another honeycomb aggregate on top of the main surface of the honeycomb aggregate, and bonding the honeycomb aggregates together with the adhesive; A method for manufacturing a honeycomb structure, comprising the steps of:

2. 2. The method for manufacturing a honeycomb structure according to claim 1, wherein the heating wires are fixed in place with an organic fixing agent, an inorganic fixing agent, or tape.

3. A method for manufacturing a honeycomb structure as described in claim 1 or 2, wherein in the heating wire arrangement process, a plurality of electrode terminals to which both ends of the heating wire are connected are fixed and arranged on the main surface of the honeycomb aggregate on which the heating wire is fixed and arranged with a fixing strength that does not shift from the designed position.

4. 4. The method for manufacturing a honeycomb structure according to claim 3, wherein a plurality of heating wires are connected in parallel between the electrode terminals.

5. 5. The method for manufacturing a honeycomb structure according to claim 1, further comprising a degreasing step of degreasing the adhesive disposed between the main surfaces of the honeycomb aggregate.

6. 6. The method for manufacturing a honeycomb structure according to claim 5, wherein in the degreasing step, a material used for fixing the heating wires to the main surfaces of the honeycomb aggregate is burned off.

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