JP6669593B2 - Honeycomb structure - Google Patents

Description

The present invention is, for example, relates to a honeycomb structure used for trapping particulate matter or the like contained in the exhaust gas of an internal combustion engine.

  As a filter for trapping particulate matter and the like (hereinafter referred to as “PM etc.”) contained in exhaust gas of an internal combustion engine, a honeycomb structure called DPF (Diesel Particulate Filter) is known (see Patent Document 1). ). The honeycomb structure is housed in a casing provided in an exhaust passage of the internal combustion engine. This honeycomb structure has a columnar shape, and is formed with a ring-shaped convex portion that protrudes outward over the entire outer peripheral surface. The ring-shaped convex portion functions to fix the honeycomb structure in the casing. In the manufacture of the honeycomb structure, a polygonal workpiece having a honeycomb structure is processed, and in the processing, the honeycomb structure is cylindrical and a ring-shaped convex portion is formed at the center in the axial direction. Grind and shape the peripheral surface of the work. The coating formed on the workpiece formed by grinding is coated with the coating layer paste on the entire peripheral surface including the ring-shaped projections to form a coating layer.

JP 2014-64978 A

In the honeycomb structure disclosed in Patent Literature 1, since the ring-shaped protrusion has a honeycomb structure, the strength of the ring-shaped protrusion is not necessarily sufficient. An object of the present invention is improving the strength of the honeycomb structure comprising a ring-shaped protrusion in FIGS Turkey.

  A honeycomb structure that achieves the above object is a columnar ceramic block in which a plurality of cells partitioned by honeycomb-shaped partition walls are arranged side by side, an exterior material layer covering a peripheral surface of the ceramic block, and the ceramic The outer peripheral surface of the block protrudes outward over the entire circumference and has a ring-shaped convex portion formed integrally with the exterior material layer.

  According to this configuration, the exterior material layer and the ring-shaped protrusion are formed as an integral body, and no cell is formed such that the ceramic block is provided in the ring-shaped protrusion. Therefore, the strength of the ring-shaped protrusion can be improved as compared with a configuration in which cells are formed on the ring-shaped protrusion.

  In the above honeycomb structure, the ring-shaped convex portion has a trapezoidal cross section, has a first inclined surface on one end side of the ceramic block and a second inclined surface on the other end side, and has It is preferable that the downward inclination angle of the first inclined surface is equal to the downward inclination angle of the second inclined surface from the top surface.

  According to this configuration, when the honeycomb structure is attached to the attachment portion using the first inclined surface and the second inclined surface, a force is uniformly applied to the inclined surfaces in the axial direction. It is possible to prevent damage to the ring-shaped protrusion without applying high stress to the protrusion in a part.

In the above honeycomb structure, it is preferable that the ring-shaped convex portion is formed including inorganic particles, inorganic fibers, and an inorganic binder.
According to this configuration, the strength of the ring-shaped projection can be further improved.

In the above honeycomb structure, it is preferable that the ceramic block is formed by binding a plurality of honeycomb members via a bonding layer.
According to this configuration, since the bonding layer and the exterior material layer are partially in contact with each other, the adhesion between the ceramic block, the outer layer material layer, and the ring-shaped protrusion is improved.

In the above honeycomb structure, it is preferable that the porosity of the partition wall is 60 to 75%.
According to this configuration, the effect of improving the strength of the ring-shaped protrusion can be maximized while reducing the pressure loss of the honeycomb structure.

In the above honeycomb structure, it is preferable that a filling layer is formed on an outer peripheral surface of the ceramic block.
By forming the filling layer between the ceramic block and the exterior material layer, peeling of the exterior material layer can be suppressed.

  In the above honeycomb structure, it is preferable that the filling layer is formed on an outer peripheral surface of a honeycomb member having a relatively large cross-sectional area among honeycomb members constituting an outermost periphery of the ceramic block.

  Of the honeycomb members constituting the outermost periphery of the ceramic block, the honeycomb member having a relatively large cross-sectional area has a small processed uneven surface on the outer peripheral surface, and thus has poor adhesion to the exterior material layer and is easily peeled. By doing so, peeling of the exterior material layer can be suppressed.

In the above-mentioned honeycomb structure, it is preferred that the filling layer is constituted as one with the exterior material layer and the ring-shaped convex portion.
According to this configuration, the adhesion between the filling layer, the exterior material layer, and the ring-shaped protrusion is improved. Further, the step of forming a filling layer is not required.

  A method for manufacturing a honeycomb structure that achieves the above object includes a ceramic block forming step of forming a columnar ceramic block in which a plurality of cells partitioned by honeycomb-shaped partition walls are juxtaposed, and extending in a circumferential direction. An arranging step of arranging the ceramic block at a predetermined distance from an inner surface of the mold inside a mold in which an annular concave groove is formed; and an exterior material between the inner surface of the mold and the ceramic block. A filling step of filling the layer paste; and a drying step of drying and solidifying the exterior material layer paste to form the exterior material layer and the ring-shaped protrusions on the ceramic block.

  According to this manufacturing method, it is possible to manufacture a honeycomb structure in which a cell in which the ceramic block is provided in the ring-shaped protrusion is not formed, and the ring-shaped protrusion is integrated with the exterior material layer. The manufacturing becomes easier as compared with a configuration in which a ring-shaped convex portion is formed by grinding a ceramic block and a paste for an application layer is applied to the ring-shaped convex portion as in the technique disclosed in Patent Document 1.

  In the method for manufacturing a honeycomb structure, the ceramic block forming step includes a step of joining a plurality of honeycomb members to form a honeycomb aggregate, and grinding a peripheral surface of the honeycomb aggregate to form a ceramic block. Is preferred.

  According to this manufacturing method, it is not necessary to grind the ceramic block so that the ring-shaped convex portion is provided on the ceramic block, and the grinding becomes easier accordingly.

  Advantageous Effects of Invention According to the present invention, the strength of the ring-shaped protrusion of the honeycomb structure having the ring-shaped protrusion is improved, and the honeycomb structure is securely placed in the casing without being damaged particularly when used in an exhaust passage. Can be fixed. Further, it is possible to easily manufacture a honeycomb structure in which the strength of the ring-shaped convex portion is improved.

(A) A perspective view of a honeycomb structure of the present embodiment. (B) The side view of the honeycomb structure of this embodiment. (A) Partial sectional drawing in the AA line in FIG. (B) The elements on larger scale of (a). (A) A perspective view of a honeycomb member. (B) BB sectional drawing of a honeycomb member. FIG. 3 is a perspective view of a honeycomb aggregate having a filling layer formed on the surface. The perspective view of the ceramic block after grinding the honeycomb aggregate which formed the filling layer on the surface. 4A and 4B show an arrangement process in a method for manufacturing a honeycomb structure, wherein FIG. 5A is a front view and FIG. FIG. 7 is a perspective view showing an arrangement step in the method for manufacturing a honeycomb structure. The front view which shows the filling process in the manufacturing method of a honey-comb structure. FIG. 5 is a perspective view showing a state in which the honeycomb structure can be taken out of the filling device after the drying step in the method for manufacturing a honeycomb structure.

One embodiment of the honeycomb structure will be described with reference to FIGS.
As shown in FIGS. 1A and 1B, the honeycomb structure 10 of the present embodiment has a ceramic block 11 having a columnar shape. The ceramic block 11 is formed by joining a plurality of columnar honeycomb members 12 with a joining layer 13. As the bonding layer, a known material used for manufacturing a honeycomb structure, for example, a material containing inorganic particles, an inorganic binder, an inorganic fiber, or the like can be appropriately used. Further, a material used for forming a filling layer and a packaging material layer described later may be selected. These may be used alone or in combination of two or more.

  As shown in FIGS. 2 and 3, the honeycomb member 12 includes a columnar peripheral wall 12a and a partition wall 12b having a honeycomb cross section that partitions the inside of the peripheral wall 12a into a plurality of cells extending in the axial direction of the peripheral wall 12a. As shown in FIGS. 3A and 3B, the cell C partitioned by the partition wall 12b has a first cell that is open at one end and closed at the other end by a sealing material 12c. C1 and a second cell C2, one end of which is closed by a sealing material 12c and the other end of which is open. The cell C functions as a fluid flow path, and when the opening of the first cell C1 is a first end face on the upstream side of the flow path and the opening of the second cell C2 is a second end face on the downstream side, the exhaust gas G is It flows into the second cell C2 from the end face through the partition 12b, and is discharged from the second end face.

  The peripheral wall and the partition wall of the honeycomb member are mainly formed of porous ceramic. Specific examples of this ceramic include nitride ceramics such as aluminum nitride, silicon nitride, boron nitride, and titanium nitride, and carbide ceramics such as silicon carbide, zirconium carbide, titanium carbide, tantalum carbide, and tungsten carbide, alumina, zirconia, Examples include cordierite, mullite, silica, oxide ceramics such as aluminum titanate, and a metal silicon-silicon carbide composite material. These may be used alone or in combination of two or more.

  The main material forming the sealing material is preferably made of the same porous ceramic as the honeycomb member from the viewpoint of securing the same characteristics as the above-mentioned honeycomb member, for example, the coefficient of thermal expansion.

  The partition wall may support an oxidation catalyst composed of a platinum group element (for example, Pt or the like) or another metal element and an oxide thereof. In this case, removal of PM and the like trapped on the surface and inside of the partition is promoted by the catalytic action of the oxidation catalyst. The upper limit of the thickness of the partition wall is preferably 0.45 mm, more preferably 0.33 mm. In such a case, for example, when removing PM or the like trapped on the surface and inside of the partition, the resistance when the exhaust gas passes through the partition is reduced, and the pressure loss can be reduced. The lower limit of the thickness of the partition wall is preferably 0.1 mm. In such a case, the mechanical strength of the honeycomb structure can be sufficiently ensured.

  The lower limit of the aperture ratio of the cells formed in the partition walls is preferably 55%, more preferably 60%. The upper limit of the cell opening ratio is preferably 70%, more preferably 65%. When the opening ratio is in such a range, the pressure loss of the honeycomb structure can be reduced. Further, the required strength of the ceramic block can be maintained. In the present invention, the opening ratio is a ratio (%) of the total of the cross-sectional areas in the vertical direction to the longitudinal direction of all the cells to the cross-sectional area of the ceramic block perpendicular to the longitudinal direction of the cells constituting the ceramic block. Say.

  The lower limit of the porosity of the partition walls is preferably 60%, more preferably 62%. The pressure loss can be reduced by setting the porosity of the partition walls to 60% or more. Further, the amount of supported catalyst can be increased, and the purification performance of exhaust gas can be improved. On the other hand, the upper limit of the porosity of the partition walls is preferably 75%, more preferably 70%. By setting the porosity of the partition walls to 75% or less, the mechanical strength of the cell partition walls can be improved, and for example, the generation of cracks at the time of regeneration of the honeycomb structure can be suppressed.

  The porosity and pore diameter of the partition are measured by a mercury porosimetry using a mercury porosimeter (Autopore IV9510 manufactured by Shimadzu Corporation) at a contact angle of 130 ° and a surface tension of 485 mN / m.

  The porosity of the partition walls can be adjusted by adjusting the particle size of the raw material, adding a pore-forming agent, firing conditions, and the like. Specific examples of the pore former include balloons that are micro hollow spheres, spherical acrylic particles, graphite, starch, and the like. Specific examples of balloons include alumina-based balloons, glass microballoons, shirasu balloons, fly ash (FA) balloons, mullite balloons, and other balloons mainly containing an oxide ceramic. These may be used alone or in combination of two or more.

  As shown in FIGS. 2A and 2B, in the first direction and the second direction, the two outermost honeycomb members 12 have the filling layer 14 bonded to the outer side of the outer peripheral wall 12 a. ing. The filling layer 14 has a joining surface 14a in contact with the peripheral wall 12a of the two honeycomb members 12 and an arc surface 14b located outside. Therefore, the peripheral surface of the ceramic block 11 is composed of the peripheral wall 12a of the honeycomb member 12, the wall end surfaces of the partition walls 12b, and the arc surface 14b of the filling layer 14.

  As shown in FIG. 1, the honeycomb structure 10 has a ring-shaped convex portion 20 formed in an annular shape. The ring-shaped protrusion 20 is located at the center of the ceramic block 11 in the direction of the central axis X, and protrudes outward over the entire outer peripheral surface of the ceramic block 11. The ring-shaped protrusion 20 has a trapezoidal cross-sectional shape in a virtual cross-section including the central axis X of the ceramic block 11. The ring-shaped projection 20 has a top surface 21 and an inner surface that is in contact with the peripheral surface of the ceramic block 11, and the top surface 21 and the inner surface face each other in the radial direction of the ceramic block 11. Further, the ring-shaped convex portion 20 has a first inclined surface 23 located on one first end 11a side of the ceramic block 11 and a second inclined surface 24 located on the other second end portion 11b side of the ceramic block 11. And Θ1 corresponding to the downward inclination angle from the top surface 21 on the first inclined surface 23 and θ2 corresponding to the downward inclination angle from the top surface 21 on the second inclined surface 24 are set to be equal.

  The ring-shaped convex portion 20 has flat portions 20A and circular arc portions 20B alternately arranged in the circumferential direction. The flat portion 20A is located in the first direction and the second direction of the ceramic block 11, and the top surface 21 is formed by a flat surface. The top surface 21 of the arc portion 20B is constituted by an arc surface.

  As shown in FIG. 1, the honeycomb structure 10 has an exterior material layer 30. The exterior material layer 30 covers the entire peripheral surface of the ceramic block 11 on the first end 11a side, and the second exterior material covers the entire peripheral surface of the ceramic block 11 on the second end 11b side. And a material layer 30B. The exterior material layer 30 and the ring-shaped convex portion 20 are configured as an integral body. Therefore, the entire peripheral surface of the ceramic block 11 is covered with the ring-shaped convex portion 20 and the exterior material layer 30 as an integral body. As shown in FIG. 1, in an imaginary cross section including the central axis X of the ceramic block 11, the angle K1 formed by the outer peripheral surface of the first exterior material layer 30A and the first inclined surface 23 of the ring-shaped convex portion 20 and the second exterior The angle K2 formed between the outer peripheral surface of the material layer 30B and the second inclined surface 24 of the ring-shaped projection 20 is set to be equal.

  The ring-shaped convex portion and the exterior material layer are integrally formed of the same material, and contain inorganic particles, inorganic fibers, and an inorganic binder. The inorganic particles function as a matrix material for the ring-shaped protrusions and the exterior material layer. Specific examples of the inorganic particles include ceramics selected from the group consisting of silicon carbide, silicon nitride, cordierite, alumina, mullite, zirconia, zirconium phosphate, aluminum titanate, titania, silica, and combinations thereof. These may be used alone or in combination of two or more.

  The inorganic fibers have a function of improving the strength of the ring-shaped convex portion and the exterior material layer. Specific examples of this type of inorganic fiber include silica-alumina fiber, mullite fiber, silica fiber, and alumina fiber. These may be used alone or in combination of two or more.

  The inorganic binder has a function of improving the strength of the ring-shaped convex portion and the exterior material layer. Specific examples of this type of inorganic binder include alumina sol, silica sol, titania sol, and the like. These may be used alone or in combination of two or more.

  Instead of the inorganic fiber or together with the inorganic fiber, an inorganic hollow body (inorganic balloon) may be contained in the ring-shaped convex portion and the exterior material layer. Specific examples of this kind of inorganic hollow body include a glass micro balloon, an alumina balloon, a mullite balloon, a silica balloon and the like. The average particle size of the inorganic hollow body is not particularly limited.

  The ring-shaped convex portion and the exterior material layer may contain an organic binder as another component. Specific examples of the organic binder include hydrophilic organic polymers such as carboxymethyl cellulose, polyvinyl alcohol, methyl cellulose, and ethyl cellulose. These may be used alone or in combination of two or more. Since the organic binder is removed by heat, it is not included in the ring-shaped convex portion and the exterior material layer after heating.

  The lower limit of the porosity of the ring-shaped convex portion and the exterior material layer is preferably 20%, more preferably 30%. By setting the porosity of the ring-shaped convex portion and the exterior material layer to 20% or more, the strength can be improved and breakage of the ring-shaped convex portion due to thermal expansion can be prevented. On the other hand, the upper limit of the porosity of the ring-shaped convex portion and the exterior material layer is lower than the porosity of the partition wall, preferably 50%, more preferably 45%. By setting the porosity of the ring-shaped protrusion and the exterior material layer to 50% or less, the strength of the ring-shaped protrusion can be improved.

  Each dimension of the honeycomb structure of the present embodiment is appropriately set. For example, the diameter of the ceramic block is preferably 140 to 150 mm, and the length in the longitudinal direction is preferably 100 to 170 mm. As the shape of the ring-shaped convex portion, X1 corresponding to the width of the base end portion in the direction of the central axis X is preferably 20 to 22 mm, and X2 corresponding to the upper surface width of the flat portion 20A is preferably 19 to 21 mm. . The height Y1 from the outer peripheral surface of the outer packaging material layer 30 in the first direction from the central axis X to the virtual peripheral surface 25 including the outer peripheral surface of the arc portion 20B is preferably 6 to 7 mm, and the outer peripheral surface of the outer packaging material layer 30 Is preferably 4 to 5 mm from the upper surface of the flat portion 20A to the upper surface. Both the inclination angle θ1 of the first inclined surface 23 with respect to the top surface 21 and the inclination angle θ2 of the second inclined surface 24 with respect to the top surface 21 are preferably 27 to 43 degrees. The thickness of the first exterior material layer 30A and the second exterior material layer 30B is preferably 0.05 to 1.0 mm.

  The honeycomb structure of the present embodiment is used as an exhaust gas purifying device, for example, by being disposed in a casing provided in the middle of an exhaust passage for discharging exhaust gas. By contacting the first inclined surface and the second inclined surface of the ring-shaped projection with the inner surface of the casing, the honeycomb structure is held in the casing, and the movement in the vertical and horizontal directions and the ventilation direction is regulated. In addition, by abutting the flat portion of the ring-shaped convex portion and the inner surface of the casing, the movement of the honeycomb structure in the circumferential direction is restricted.

  Hereinafter, the method for manufacturing the honeycomb structure of the present invention will be specifically described. In addition, the manufacturing method of the honeycomb structure of the present invention is not limited to the following configuration, and can be appropriately changed and applied without changing the gist of the present invention.

  A method for manufacturing a honeycomb structure will be described with reference to FIGS. The honeycomb structure is manufactured by sequentially performing a ceramic block forming step, an arrangement step, a filling step, and a drying step.

(Ceramic block forming process)
The ceramic block forming step includes a forming step, a joining step, and a grinding step.
[Molding process]
The honeycomb formed body has a quadrangular prism shape composed of four peripheral walls, and is provided with partition walls having a honeycomb cross section that divides the inside of the peripheral wall into a plurality of cells extending in the axial direction of the peripheral wall. The raw material composition containing the ceramic powder and the binder is extruded using an extruder to form a honeycomb formed body. The extruded honeycomb formed body is dried using a dryer. As the raw material composition, the materials used for the above-described honeycomb structure can be used. For the drying treatment, a known treatment used in the manufacturing process of the honeycomb structure can be employed.

  The dried honeycomb formed body is cut into a desired length using a cutting device. A first cell and a second cell are formed by filling the cut end face with a predetermined amount of a sealing material paste and plugging the cells. The dried honeycomb formed body is dried and heated in a degreasing furnace to be degreased, and then fired in a firing furnace to produce a honeycomb member.

[Joining process]
In the honeycomb member joining step, 16 honeycomb members are joined to each other. The honeycomb members are parallel to each other in the axial direction, and are adjacent to each other, and the opposing peripheral walls are arranged at predetermined intervals so that the surface directions are parallel. A joining layer is formed between the peripheral walls, and the honeycomb members are joined by the joining layer so as to form a quadrangular prism.

  As shown in FIG. 4, a rectangular plate-like filling layer 31 was formed on the wall surface of the joined honeycomb member 12 by applying and drying a slurry containing the filling member. The filling layer 31 is disposed on the four wall surfaces of the joined honeycomb members so as to cover the end surfaces of the bonding layer 13 exposed on the four wall surfaces. In this way, the honeycomb members 12 are joined to each other to produce a honeycomb aggregate 32 having the filling layer 31 on the peripheral wall.

[Grinding process]
The honeycomb block 32 is ground using a grinding machine equipped with a diamond cutter so that the shape of the honeycomb aggregate 32 is cylindrical, whereby the cylindrical ceramic block 11 shown in FIG. 5 is manufactured.

(Placement process)
The arranging step is a step of arranging the ceramic block 11 in a filling device for forming a ring-shaped convex portion and an exterior material layer. As shown in FIGS. 6A and 6B and FIG. 7, the filling device 80 has a mounting plate 81 as a mold formed in a disk shape, and above the mounting plate 81, There is a pressing plate 82 as a mold formed in the same manner as the mounting plate 81. The mounting plate 81 and the pressing plate 82 are arranged such that their central axes are coaxial with each other. The mounting surface 81a of the mounting plate 81 and the pressing surface 82a of the pressing plate 82 are set so that the surface directions are parallel to each other. The mounting plate 81 has a filling portion 81b having a valve function. The pressing plate 82 has a communicating portion 82b that communicates the inside and the outside. The filling device 80 has a first driving unit E1 that reciprocates the pressing plate 82 in the vertical direction. The pressing plate 82 approaches and separates from the mounting plate 81 by controlling the driving of the first driving unit E1.

  The filling device 80 has a pair of side plates 83 and 84 as molds facing each other in the horizontal direction. The side plates 83 and 84 have the same shape, and the opposing surfaces where the side plates 83 and 84 face each other are arcuate concave surfaces 83a and 84a concave in a semi-cylindrical shape at the center and arcuate concave surfaces at both ends. The contact surfaces 83b and 84b are adjacent to the contact surfaces 83a and 84a. A concave groove 85 is formed in each of the circular concave surfaces 83a and 84a. The concave groove 85 is a groove formed in the center of the side plates 83 and 84 in the vertical direction over a semicircle from one contact surface 83b, 84b to the other contact surface 83b, 84b. . The filling device 80 includes a second driving unit E2, and the side plates 83 and 84 approach and separate from each other by controlling the driving of the second driving unit E2. When the side plates 83 and 84 are arranged at the approach position, the contact surfaces 83b and 84b contact each other. In addition, a cylindrical space is formed by the pair of arc-shaped concave surfaces 83a and 84a, and a concave groove 85 is formed at the center in the vertical direction so as to extend annularly over the entire circumference in the circumferential direction.

  The concave groove 85 includes a pair of side surfaces 85a and a bottom surface 85b. The pair of side surfaces 85a are formed as inclined surfaces approaching each other from the opening side toward the bottom surface 85b. The bottom surface 85b includes a flat surface and an arc surface along the arc of the arc concave surfaces 83a and 84a. The flat surface and the arc surface are alternately formed in the circumferential direction, and the circumferential length L1 of the flat surface extending from the pair of contact surfaces 83b and 84b is located at the deepest side of the arc concave surfaces 83a and 84a. It is set to half of the circumferential length L2 of the flat surface to be formed. Therefore, when the pair of side plates 83 and 84 are arranged at the approach position, the shape of the bottom surface 85b of the concave groove 85 is such that four flat surfaces having a circumferential length L2 and four arc surfaces in the circumferential direction are provided. The shapes are alternately arranged.

  In the placing step, the ceramic block 11 is placed on the placing surface 81 a of the placing plate 81. At this time, an air-permeable release sheet is placed on the placement surface 81a, and one end surface of the ceramic block 11 is placed on the release sheet. The release sheet has an opening corresponding to the filling portion 81b formed on the mounting plate 81. The placed ceramic block 11 is arranged so that the central axis of the ceramic block 11 and the central axis of the placing plate 81 match. The diameter of the ceramic block 11 is set smaller than the diameter of the mounting plate 81. Therefore, when the ceramic block 11 is placed on the placement surface 81a of the placement plate 81, the outer peripheral side of the release sheet on the placement surface 81a is exposed.

  The pressing plate 82 has an air-permeable release sheet disposed on the pressing surface 82a. The pressing plate 82 is arranged at an approach position close to the mounting plate 81 by driving of the first driving unit E1. At this time, the pressing surface 82a of the pressing plate 82 presses the other end surface of the ceramic block 11 mounted on the mounting surface 81a of the mounting plate 81. The pressing by the pressing plate 82 positions the ceramic block 11 between the mounting block 81 and the ceramic block 11.

  The pair of side plates 83 and 84 approach each other by driving of the second driving unit E2. An air-permeable release sheet is disposed on the inner surfaces of the arcuate concave surfaces 83a and 84a of the pair of side plates 83 and 84, respectively. As shown in FIG. 8, a pair of side plates 83 and 84 are arranged at an approaching position where the contact surfaces 83b and 84b are in contact with each other, and the concave concave surfaces 83a and 84a and the mounting surface 81a and the pressing surface are provided. The side surface 82a contacts. Due to the contact between the plates, a cylindrical shape sealed in the inner area surrounded by the mounting surface 81a of the mounting plate 81, the pressing surface 82a of the pressing plate 82, and the arcuate concave surfaces 83a, 84a of the side plates 83, 84. Is formed. At this time, a predetermined gap is formed between the arcuate concave surfaces 83a, 84a of the side plates 83, 84 and the peripheral surface of the ceramic block 11.

(Filling process)
The filling step is a step of filling the gap between the ceramic block housed in the filling device and the arc-shaped concave surface of the side plate with the exterior material layer paste. As shown in FIG. 8, the packaging material layer paste is filled via the filling portion 81 b of the mounting plate 81. The paste for the exterior material layer filled in the filling space spreads over the gap between the peripheral surface of the ceramic block 11 and the concave circular surfaces 83a, 84a of the side plates 83, 84. With the filling of the exterior material layer paste, the air in the filling space is discharged to the outside through the communicating portion 82b of the pressing plate 82. In addition, as the paste for the exterior material layer and the release sheet, the conventional paste used in the manufacture of the honeycomb structure can be used.

(Drying process)
The drying step is a step in which the exterior material layer paste filled in the filling space is dried and solidified. After the gap between the peripheral surface of the ceramic block and the concave circular surface of the side plate is filled with the exterior material layer paste, each plate is heated. By this heating, the exterior material layer paste is dried and solidified, and as shown in FIG. 9, the honeycomb structure 10 in which the ring-shaped projections 20 and the exterior material layer 30 are formed on the peripheral surface of the ceramic block 11 is manufactured. You.

The operation and effect of the honeycomb structure of the present embodiment will be described.
(1) The entire peripheral surface of the ceramic block is covered with an exterior material layer and a ring-shaped convex portion that are formed as an integral body. Here, the ring-shaped convex portion is not configured to have a cell provided in the ceramic block. Therefore, the strength of the ring-shaped protrusion can be improved as compared with a configuration in which cells are formed on the ring-shaped protrusion.

  (2) The first inclined surface and the second inclined surface of the ring-shaped convex portion are set to have the same downward inclination angle from the top surface. Therefore, when the honeycomb structure is attached to the attachment portion using the first inclined surface and the second inclined surface, a force acts uniformly on each of the first inclined surface and the second inclined surface in the axial direction. Therefore, damage to the ring-shaped convex portion can be prevented without applying high stress to the ring-shaped convex portion.

(3) The ring-shaped convex portion is formed including inorganic particles, inorganic fibers, and an inorganic binder. Therefore, the strength of the ring-shaped protrusion can be further improved.
(4) In the ceramic block, a plurality of honeycomb members are bound via a bonding layer. Therefore, since the bonding layer and the exterior material layer are partially in contact with each other, the adhesion between the ceramic block and the outer layer material layer and the ring-shaped projections is improved.

  (5) The ring-shaped convex portion is formed by a filling step of filling the paste for the exterior material layer between the inner surface of the mold and the ceramic block, and a drying step of drying and solidifying the paste for the exterior material layer, thereby forming the ceramic block. Ring-shaped convex portions can be formed on the substrate. Therefore, a plurality of cells such as those provided in the ceramic block in the ring-shaped protrusion are not formed, and the honeycomb structure in which the ring-shaped protrusion and the exterior material layer are integrated is easily manufactured. it can.

  (6) As described above, the ring-shaped convex portion is formed on the peripheral surface of the ceramic block through the characteristic configuration of the filling step and the drying step. Therefore, for example, the production becomes easier as compared with a configuration in which the ring-shaped convex portion is formed by grinding the honeycomb aggregate, and the exterior material layer is applied to the ring-shaped convex portion of the manufactured ceramic block.

  (7) In a ceramic block forming step of forming a ceramic block, a plurality of honeycomb members are joined to form a honeycomb aggregate, and the peripheral surface of the honeycomb aggregate is ground to form a ceramic block. According to this method of manufacturing a ceramic block, it is not necessary to grind the ceramic block so that the ring-shaped projection is provided on the ceramic block, and the grinding of the ceramic block becomes easier.

  (8) In the ceramic block forming step of forming the ceramic block, a filling layer is formed on the joined honeycomb members. The filling layers are respectively disposed on the four outer wall surfaces of the joined honeycomb members. Since the honeycomb aggregate on which the filling layer is formed in this way is subjected to a grinding step of grinding the peripheral surface, the bonding state of the honeycomb members during grinding is stabilized.

The above embodiment may be modified as follows. Further, the configuration of the above-described embodiment and the configuration shown in the following modified examples can be appropriately combined and implemented.
-The shape of the honeycomb structure is not limited to a columnar shape. For example, it can be formed in a polygonal shape. In accordance with such a change in the shape of the honeycomb structure, the shape of each plate of the filling device is also changed.

  -A coating layer may be further formed on the peripheral surface of the ceramic block. In this case, a coating layer will be formed on the outer peripheral surfaces of the exterior material layer and the ring-shaped protrusion. The roundness of the end face of the honeycomb structure is improved by forming the coating layer. In addition, this coating layer may be a multilayer.

  -Although a ring-shaped convex part was comprised from four flat parts and four circular arc parts, it is not limited to this structure. For example, it is possible to form a ring-shaped convex portion from a portion other than eight, such as a configuration including three flat portions and three arc portions. Further, it is also possible to configure all parts only with a flat part or only with a circular arc part. The combination of these flat portions and arc portions can be variously changed.

  -Although a ring-shaped convex part was formed in the axial center of the ceramic block, it is not limited to this. The position may be changed to the position on the first end side of the ceramic block, or may be changed to the position on the second end side.

  -The downward inclination angle between the first inclined surface and the second inclined surface of the ring-shaped convex portion can be changed. For example, it is possible to set the downward inclination angles to be different from each other. Of course, the setting of the downward inclination angle itself can be changed according to the mode of the attached portion. Further, it is also possible to configure a vertical surface without inclining at least one of the first inclined surface and the second inclined surface.

  -The grinding step can be omitted in the ceramic block forming step. In this case, a plurality of types (three types in the above embodiment) of the honeycomb members including the honeycomb members having the arc wall on the peripheral wall are extruded in the forming step, and the honeycomb members thus manufactured have a columnar shape as a whole. In this way, the honeycomb aggregates are joined together to produce a honeycomb aggregate.

  -The configuration of the packed layer of the honeycomb aggregate can be changed. For example, it is possible to change the size of the filling layer and expose some of the bonding layers. Also, the thickness can be set to be thicker or thinner according to the diameter of the ceramic block to be manufactured. Further, it is also possible to configure so that the honeycomb aggregate is not provided with the filling layer. In the case where the honeycomb aggregate is not provided with the filling layer, the peripheral surface of the ceramic block includes the outer surface (flat surface) of the peripheral wall of the honeycomb member that has not been subjected to grinding, the peripheral wall of the honeycomb member and the end surface (arc surface) of the partition wall, the bonding layer. Or the end surface (arc surface) of the peripheral wall of the honeycomb member and the partition wall, and the end surface of the bonding layer. In the filling step, the gap between the peripheral surface of the ceramic block and the side plate is filled with the exterior material layer paste. Therefore, when the peripheral surface of the ceramic block is composed of a plurality of flat surfaces and a plurality of arc surfaces, as the honeycomb structure, the exterior material layer, the ring-shaped convex portions, and the filling layer are integrally formed. It will be.

  In the filling device used in the arrangement step, the filling step, and the drying step, the release sheet is disposed on each plate, but the present invention is not limited to this configuration. Each plate itself may be made of a material having a release function, or a release function may be achieved by applying a release agent to each plate. In addition, it is also possible to make the paste for the exterior material layer to be filled so that it is easy to release after drying.

  DESCRIPTION OF SYMBOLS 10 ... Honeycomb structure, 11 ... Ceramic block, 12 ... Honeycomb member, 12b ... Partition wall, 13 ... Joining layer, 20 ... Ring-shaped convex part, 21 ... Top surface, 23 ... 1st inclined surface, 24 ... 2nd inclined surface , 30 ... exterior material layer, 31 ... filling layer, 32 ... honeycomb assembly, 80 ... filling device, 81 ... mounting plate, 82 ... pressing plate, 83, 84 ... side plate, 83a, 84a ... circular concave surface, C …cell.

Claims (7)

A column-shaped ceramic block in which a plurality of cells partitioned by partition walls having a honeycomb sectional shape are arranged in parallel, an exterior material layer covering a peripheral surface of the ceramic block, and an outer peripheral surface of the ceramic block over the entire circumference. possess a ring-shaped protrusion that is configured as the outer material layer and one piece with outwardly projecting,
The ring-shaped convex portion has a trapezoidal cross section, has a first inclined surface on one end side of the ceramic block, has a second inclined surface on the other end side, and descends from the top surface of the first inclined surface. A honeycomb structure having an inclination angle equal to a downward inclination angle of the second inclined surface from a top surface . The honeycomb structure according to claim 1, wherein the ring-shaped convex portion is formed including inorganic particles, inorganic fibers, and an inorganic binder. It said ceramic block, a honeycomb structure according to claim 1 or 2 more honeycomb members, which are bound together through the bonding layer. The honeycomb structure according to any one of claims 1 to 3 , wherein the partition walls have a porosity of 60 to 75%. The honeycomb structure according to claim 3 or 4 filling layer is formed on the outer peripheral surface of the ceramic block. The honeycomb structure according to claim 5 , wherein the filling layer is formed on an outer peripheral surface of a honeycomb member having a relatively large cross-sectional area among honeycomb members constituting an outermost periphery of the ceramic block. The packed bed, the honeycomb structure according to claim 5 or 6, characterized in that it is constituted as the exterior material layer and the ring-shaped convex portion integrally thereof.

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