JP2014188882A - Honeycomb structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a honeycomb structure the thermal shock resistance of which is improved without excessively increasing the heat capacity or pressure loss thereof.SOLUTION: The honeycomb structure has: porous partition walls 3 which are used for dividedly forming a plurality of cells so that two end faces thereof are communicated with each other; an outer peripheral wall 4 formed integrally with the partition walls 3; and such a shape that an outer peripheral shape of the cross section perpendicular to the longitudinal direction thereof contains a curve. The plurality of cells comprise perfect cells 5 each having a perfect tetragonal cell cross section and imperfect cells 6 each having an imperfect cross section because a part of the cross section is contacted with the outer peripheral wall 4 so that a tetragon is not formed. The triangular imperfect cells 6a, at least a part of each of which exists in a predetermined region, 20a, 20b, 20c or 20d, are selected. When a corner, which is of the selected triangular imperfect cell 6a and is formed at an intersection of the partition wall 3 and the outer peripheral wall 4, has an obtuse angle, the corner is thickened so that the corner has a shape selected from the group consisting of an R-letter shape, an inverted R-letter shape and a C-plane shape.

Description

  The present invention relates to a honeycomb structure used for a catalyst carrier in an exhaust gas purification catalytic converter, a particulate collection filter such as a diesel particulate filter, and the like.

  Honeycomb structures are widely used for catalyst carriers in exhaust gas purifying catalytic converters of internal combustion engines such as automobile engines, particulate collection filters such as diesel particulate filters (DPF), and the like.

  Since the honeycomb structure used in such an application is exposed to a steep temperature change, high thermal shock resistance is required so as not to be damaged by the temperature change. As means for improving the thermal shock resistance of the honeycomb structure, it is generally known to increase the heat capacity or enhance the structural durability. For example, Patent Document 1 discloses a honeycomb structure in which all cells located in the outermost peripheral portion are filled with a ceramic material. Patent Document 2 discloses a honeycomb structure in which 90% or more of cells located in a predetermined outer peripheral region are closed.

JP 63-12658 A JP 2004-154768 A

  However, if most of the cells located on the outer peripheral portion are closed in this way, the heat capacity becomes too large, and it takes time to raise the honeycomb structure carrying the catalyst to the operating temperature of the catalyst, and the internal combustion engine The exhaust gas purification performance at the start of the engine is reduced. Moreover, since the pressure loss also increases, the fuel consumption of the internal combustion engine deteriorates.

  The present invention has been made in view of such circumstances, and its object is to provide a honeycomb structure having improved thermal shock resistance without excessively increasing heat capacity and pressure loss. It is in.

  In order to achieve the above object, according to the present invention, the following honeycomb structure is provided.

[1] An outer periphery of a cross section having a porous partition wall defining a plurality of cells communicating between two end faces and an outer peripheral wall formed integrally with the partition wall and perpendicular to the longitudinal direction thereof The shape of the cell includes a curved line, and the cell includes a complete cell having a square complete cell cross section and a non-square cross section because a part of the cell is in contact with the outer peripheral wall. A straight line extending through the center of gravity of the end cell and extending in the diagonal direction of the square, which is the cross-sectional shape of the complete cell, within a rotation region when the center of gravity is rotated within a range of ± 5 °. Are included in at least a part thereof, and at least a corner portion formed at the intersection of the partition wall and the outer peripheral wall that defines an incomplete cell having a triangular cross-sectional shape. The corner where the angle is obtuse is an R shape A honeycomb structure that is thickened so as to have any shape selected from the group consisting of an inverted R shape and a C-plane shape.

[2] Of the corners, only the corners having an obtuse angle are thickened so as to have any shape selected from the group consisting of an R shape, an inverted R shape, and a C surface shape. The honeycomb structure according to [1].

[3] The device according to [1] or [2], wherein a plugging member that plugs one open end of a predetermined cell and plugs the other open end of the remaining cell is formed. Honeycomb structure.

[4] An outer periphery of a cross section having a porous partition wall defining a plurality of cells communicating between two end faces and an outer peripheral wall formed integrally with the partition wall and perpendicular to the longitudinal direction thereof The shape of the cell includes a curved line, and the cell includes a complete cell having a square complete cell cross section and a non-square cross section because a part of the cell is in contact with the outer peripheral wall. A straight line extending through the center of gravity of the end cell and extending in the diagonal direction of the square, which is the cross-sectional shape of the complete cell, within a rotation region when the center of gravity is rotated within a range of ± 5 °. A honeycomb structure in which at least a part thereof is included and incomplete cells having a triangular cross-sectional shape are closed over the entire length thereof.

[5] Except for the incomplete cells that are blocked over the entire length, plug one open end of a predetermined cell and plug the other open end of the remaining cells. The honeycomb structure according to [4], wherein a plugging member is formed.

  The honeycomb structure of the present invention is obtained by reinforcing (selectively) only a specific portion where stress is concentrated when a sudden temperature change occurs by thickening corners or blocking cells. is there. For this reason, the honeycomb structure of the present invention exhibits high thermal shock resistance without causing an excessive increase in heat capacity or pressure loss.

1 is a schematic perspective view showing an example of an embodiment of a honeycomb structure according to the present invention. It is the schematic plan view seen from the end surface direction showing an example of an embodiment of a honeycomb structure according to the present invention. It is explanatory drawing which shows what the triangular incomplete cell in this invention is. It is the principal part enlarged view which expanded and showed the triangular imperfect cell in which at least one part is included in a rotation area | region, and the periphery site | part. It is explanatory drawing which shows the method of measuring the angle of a corner | angular part. It is a principal part enlarged view which shows the state of the corner | angular part thickened so that it might become R shape. It is a principal part enlarged view which shows the state of the corner | angular part thickened so that it may become reverse R shape. It is a principal part enlarged view which shows the state of the corner | angular part thickened so that it might become C surface shape. It is a principal part enlarged view which shows the state with which the triangular imperfect cell in which at least one part was included in the rotation area | region was obstruct | occluded. It is a graph which shows the evaluation result of Examples 1-8 and Comparative Examples 1-7. It is a graph which shows the evaluation result of Examples 9-15 and Comparative Examples 8-12.

  Hereinafter, the present invention will be described based on specific embodiments, but the present invention should not be construed as being limited thereto, and based on the knowledge of those skilled in the art without departing from the scope of the present invention. Various changes, modifications, and improvements can be added.

(1) Honeycomb structure:
FIG. 1 is a schematic perspective view showing an example of an embodiment of a honeycomb structure according to the present invention, and FIG. 2 is a schematic plan view seen from an end face direction showing an example of an embodiment of a honeycomb structure according to the present invention. It is.

  A honeycomb structure 1 according to the present invention includes a porous partition wall 3 that partitions and forms a plurality of cells communicating between two end faces 10 and 11, and an outer peripheral wall 4 that is formed integrally with the partition wall 3. . The cell includes a complete cell 5 having a square complete cell cross section and an incomplete cell 6 having an incomplete cross section without forming a quadrangle because a part thereof is in contact with the outer peripheral wall 4. The incomplete cell 6 includes an incomplete cell having a triangular cross section (hereinafter referred to as “triangular incomplete cell”) 6a and an incomplete cell 6b having a cross section other than the triangular shape. And exist. The term “triangular” as used herein does not only mean that the cross-sectional shape of the cell is a perfect triangle, but a part of the contour (the portion in contact with the outer peripheral wall 4) constituting the cross-sectional shape of the cell. ) Includes a curved shape such as an arc. Specifically, as shown in FIG. 3, when the intersection of the partition wall 3 and the outer peripheral wall 4 that define the incomplete cell 6 is connected by the line segment S, the line segment S and its incompleteness are connected. When a triangle is formed by the partition walls 3 that define the cell 6, the incomplete cell is defined as a triangular incomplete cell 6a.

  In the honeycomb structure 1 according to the present invention, the corner portion formed at the intersection of the partition wall 3 and the outer peripheral wall 4 that define the triangular incomplete cell 6a including at least a part thereof in a specific region. Of these, at least the corners whose angles are obtuse are thickened. As shown in FIG. 2, the specific region referred to here is a straight line L1, L2 that extends in the diagonal direction of a quadrangle that is a cross-sectional shape of the complete cell 5 through the center of gravity G of the end surface. The rotation regions 20a, 20b, 20c, and 20d when rotated within a range of 5 °. In the present specification, hereinafter, such a rotation region is simply referred to as a “rotation region”.

  FIG. 4 is an enlarged view of a main part showing the triangular imperfect cell 6a including at least a part thereof in the rotation regions 20a, 20b, 20c, and 20d and the surrounding portion. In the corner portion 8 formed at the intersection of the partition wall 3 and the outer peripheral wall 4 that define the triangular imperfect cell 6a that includes at least a part of the rotation region 20a, 20b, 20c, 20d, There are a corner portion 8a having an obtuse angle and a corner portion 8b having an acute angle. As a result of the thermal stress analysis, the present inventors investigated stress concentration sites when a sudden temperature change occurred in the honeycomb structure, and it was found that stress was concentrated on these corner portions 8, particularly the corner portions 8a. It was.

  Based on such knowledge, the honeycomb structure 1 according to the present invention is obtained by thickening at least the corner portion 8a having an obtuse angle among the corner portions 8a and 8b. When a sharp temperature change occurs in the honeycomb structure, the corner portion 8a, which is a part where stress is concentrated, is selectively thickened, so that heat capacity and pressure loss are not increased excessively. Impact properties can be effectively improved. In the honeycomb structure 1 according to the present invention, both the corner portion 8a having an obtuse angle and the corner portion 8b having an acute angle may be thickened, but only the corner portion 8a is formed. A sufficient thermal shock resistance improving effect can be obtained only by increasing the thickness. In addition, it is possible to suppress an increase in pressure loss due to the thickening of the corner portion by reducing the thickness of only the corner portion 8a rather than increasing the thickness of both the corner portion 8a and the corner portion 8b.

  In addition, when a part of the contour (part in contact with the outer peripheral wall 4) constituting the cross-sectional shape of the triangular imperfect cell 6a is a curved shape such as an arc, the triangular imperfect cell 6a is partitioned. The angle of the corner formed at the intersection of the partition wall 3 and the outer peripheral wall 4 is determined as follows. First, as shown in FIG. 5, the line segments S1, S2, and S3 connect the intersections between the partition wall 3 and the outer peripheral wall 4 that define the triangular imperfect cell 6a and the imperfect cell 6b adjacent thereto. Then, the angles α1, α2, β1, β2 of the corners formed by these line segments S1, S2, S3 and the partition walls 3 are obtained. In FIG. 5, α1 and α2 are obtuse angles and β1 and β2 are acute angles among the angles of the corners thus determined.

  In the honeycomb structure 1 according to the present invention, the corner portion 8 is thickened so as to have any shape selected from the group consisting of an R shape, an inverted R shape, and a C surface shape. FIG. 6 shows a state where the corner portion 8a is thickened so as to be an R shape, and FIG. 7 shows a state where the corner portion 8a is thickened so as to be an inverted R shape. ing. FIG. 8 shows a state where the corner 8a is thickened so as to have a C-plane shape. 6-8, only the corner | angular part 8a is thickened, but as above-mentioned, both the corner | angular part 8a and the corner | angular part 8b may be thickened.

  When the corner portion 8 is thickened so as to have an R shape or an inverted R shape, the R (curvature radius) is preferably 80 μm or more, and more preferably 100 μm or more. Moreover, when the corner | angular part 8 is thickened so that it may become C surface shape, it is preferable that C is 55 micrometers or more, and it is still more preferable that it is 70 micrometers or more. If R is less than 80 μm or C is less than 55 μm, a sufficient thermal shock resistance improving effect may not be obtained.

  In the honeycomb structure 1 according to the present invention, the corner portions to be thickened as described above define the triangular incomplete cells 6a including at least a part of the rotation regions 20a, 20b, 20c, and 20d. Only the corner 8 formed at the intersection of the partition wall 3 and the outer peripheral wall 4. If the other corners are also thickened, the thermal capacity and pressure loss are excessively increased even if the thermal shock resistance is improved.

  In the honeycomb structure 1 according to the present invention, instead of the thickening of the corners as described above, the triangular imperfect cells 6a including at least a part of the rotation regions 20a, 20b, 20c, and 20d are provided. It may be occluded over its entire length. FIG. 9 shows a state where the triangular imperfect cell 6 a including at least a part of the rotation regions 20 a, 20 b, 20 c, and 20 d is closed by the filler 12. In this way, by selectively closing the triangular imperfect cell 6a including at least a part thereof in the rotation regions 20a, 20b, 20c, and 20d, without causing an excessive increase in heat capacity and pressure loss, The thermal shock resistance can be effectively improved.

  In the honeycomb structure 1 according to the present invention, as described above, the incomplete cells that are blocked over the entire length of the honeycomb structure 1 have a triangular shape in which at least a part thereof is included in the rotation regions 20a, 20b, 20c, and 20d. Only the incomplete cell 6a. If even other incomplete cells are blocked, the thermal capacity and pressure loss are excessively increased even if the thermal shock resistance is improved.

  In the honeycomb structure 1 according to the present invention, the outer peripheral shape of a cross section perpendicular to the length direction includes a curve. Specific examples of the shape include an oval shape and an oval shape (oval shape) in addition to the circular shape shown in FIG. In addition, the cell shape of the complete cell 5 of the honeycomb structure 1 according to the present invention (cell shape in a cross section orthogonal to the axial direction of the cell) is a quadrangle such as a square or a rectangle.

  When the honeycomb structure 1 according to the present invention is used in a particulate collection filter such as a DPF, one opening end of a predetermined cell is plugged and the other opening end of the remaining cell is plugged. It is preferable that a plugging member to be sealed is formed. Thus, by plugging one open end of each cell with the plugging portion, the honeycomb structure becomes a wall flow type particulate collection filter. The plugged portion has one end surface and the other end surface of the honeycomb structure, each of which has an open end portion plugged by the plugged portion, and an open end portion by the plugged portion. It is preferably formed so as to have a checkered pattern with cells that are not plugged. However, in a honeycomb structure having triangular imperfect cells that are closed over the entire length, the triangular imperfect cells are excluded from the plugging portion formation targets.

  When the honeycomb structure 1 according to the present invention is used as a catalyst carrier in an exhaust gas purifying catalytic converter, it is preferable that an exhaust gas purifying catalyst is supported on the partition walls 3. Examples of the exhaust gas purifying catalyst supported on the partition wall 3 include conventionally known catalysts such as a three-way catalyst, an SCR catalyst, and an oxidation catalyst.

  The material for forming the honeycomb structure 1 according to the present invention is not particularly limited, but is preferably a ceramic material. In particular, because of its excellent strength and heat resistance, it is selected from the group consisting of cordierite, silicon carbide, silicon-silicon carbide based composite material, mullite, alumina, aluminum titanate, silicon nitride, and silicon carbide-cordierite based composite material At least one ceramic material can be suitably used.

  Further, when forming the plugged portion, it is preferable to use the same material as the material for forming the honeycomb structure as the material for forming the plugged portion. By doing so, the difference in thermal expansion between the honeycomb structure and the plugged portion can be reduced, and the thermal stress generated between the honeycomb structure and the plugged portion can be reduced.

  In the honeycomb structure 1 according to the present invention, the average pore diameter of the partition walls 3 is not particularly limited, but is preferably 5 to 40 μm, and more preferably 10 to 25 μm. If the average pore diameter of the partition walls 3 is less than 5 μm, the pressure loss of the honeycomb structure may become too large. On the other hand, if the average pore diameter of the partition walls 3 exceeds 40 μm, sufficient strength may not be obtained. Here, the “average pore diameter” is a value measured by a mercury porosimeter.

  In the honeycomb structure 1 according to the present invention, the porosity of the partition walls 3 is not particularly limited, but is preferably 30 to 85%, and more preferably 35 to 70%. If the porosity of the partition walls 3 is less than 30%, the pressure loss of the honeycomb structure may be too large. On the other hand, if the porosity of the partition wall 3 exceeds 85%, sufficient strength may not be obtained. The “porosity” mentioned here is a value measured by a mercury porosimeter.

  In the honeycomb structure 1 according to the present invention, the thickness of the partition wall 3 is not particularly limited, but is preferably 100 to 600 μm, and more preferably 110 to 560 μm. If the thickness of the partition wall 3 is less than 100 μm, sufficient strength may not be obtained. On the other hand, if the thickness of the partition wall 3 exceeds 600 μm, the pressure loss of the honeycomb structure may become too large.

In the honeycomb structure 1 according to the present invention, the cell density is not particularly limited, but is preferably 10 to 70 cells / cm ² , and more preferably 15 to 50 cells / cm ² . When the cell density is less than 10 cells / cm ² , the contact efficiency with the exhaust gas may decrease. On the other hand, if the cell density exceeds 70 cells / cm ² , sufficient strength may not be obtained.

  The honeycomb structure according to the present invention can be suitably used for a catalyst carrier in an exhaust gas purification catalytic converter, a particulate collection filter such as DPF, and the like.

(2) Manufacturing method of honeycomb structure:
Hereinafter, an example of a method for manufacturing a honeycomb structure according to the present invention will be described. First, a forming raw material containing a ceramic raw material is mixed and kneaded to obtain a clay. The ceramic raw material is selected from the group consisting of cordierite forming raw material, cordierite, silicon carbide, silicon-silicon carbide based composite material, mullite, alumina, aluminum titanate, silicon nitride, and silicon carbide-cordierite based composite material. At least one of these is preferred. The cordierite forming raw material is a raw material that becomes cordierite by being fired. Specifically, silica is 42 to 56% by mass, alumina is 30 to 45% by mass, and magnesia is 12 to 16%. It is a raw material blended to have a chemical composition that falls within the range of mass%.

  The forming raw material is preferably prepared by mixing the ceramic raw material with a dispersion medium, a sintering aid, an organic binder, a surfactant, a pore former, and the like.

  It is preferable to use water as the dispersion medium. The content of the dispersion medium is appropriately adjusted so that the clay obtained by kneading the molding raw material has a hardness that facilitates molding. The specific content of the dispersion medium is preferably 20 to 80% by mass with respect to the entire forming raw material.

  As a sintering aid, for example, yttria, magnesia, strontium oxide and the like can be used. The content of the sintering aid is preferably 0.1 to 0.3% by mass with respect to the entire forming raw material.

  Examples of the organic binder include methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. Among these, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. The content of the binder is preferably 2 to 10% by mass with respect to the entire forming raw material.

  As the surfactant, 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. The content of the surfactant is preferably 2% by mass or less with respect to the whole forming raw material.

  The pore former is not particularly limited as long as it becomes pores after firing, and examples thereof include graphite, starch, foamed resin, hollow resin, water absorbent resin, and silica gel. The pore former content is preferably 10% by mass or less based on the entire forming raw material.

  Next, the forming raw material is kneaded to form a clay. There is no restriction | limiting in particular as a method of kneading | mixing a shaping | molding raw material and forming a clay, For example, the method of using a kneader, a vacuum clay kneader, etc. can be mentioned.

  Next, the obtained clay is formed to form a honeycomb-shaped formed body (honeycomb formed body). As a method of forming a kneaded clay to form a honeycomb formed body, it is preferable to use extrusion molding. In this extrusion molding, a portion corresponding to the corner portion to be thickened uses a base having a shape corresponding to the thickened state, and extrudes the clay through the base, thereby obtaining a predetermined corner. A honeycomb molded body having a thickened portion is obtained. In addition, in the case where a predetermined triangular imperfect cell is closed over its entire length instead of increasing the thickness of the predetermined corner, firstly, the increase in thickness of the predetermined corner as described above is supported. A normal honeycomb formed body is extruded using a general die that is not used. Thereafter, by filling a predetermined triangular imperfect cell of the obtained honeycomb formed body with a filler, the triangular imperfect cell is closed over its entire length. It is preferable to use the same material as the forming raw material for the filler. The filling of the filler may be performed after the honeycomb formed body is dried.

  The honeycomb formed body thus obtained is dried and then fired. Examples of the drying method include hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying, and the like. Among them, it is preferable to perform dielectric drying, microwave drying, or hot air drying alone or in combination.

  The dried honeycomb formed body is preferably calcined before firing (main firing). Calcination is performed for degreasing. There is no restriction | limiting in particular about the method of calcination. For example, it is sufficient that at least a part of the organic matter in the honeycomb formed body can be removed. Examples of the organic material include an organic binder, a surfactant, and a pore former. The combustion temperature of the organic binder is about 100 to 300 ° C. For this reason, calcination is preferably performed at about 200 to 1000 ° C. for about 10 to 100 hours in an oxidizing atmosphere.

  The firing (main firing) of the honeycomb formed body is performed to sinter and densify the forming raw material constituting the calcined honeycomb formed body to ensure a predetermined strength. Since the firing conditions differ depending on the type of molding raw material, appropriate conditions may be selected according to the type. For example, when the cordierite forming raw material is used, the firing temperature is preferably 1350 to 1440 ° C. In addition, the firing time is preferably 3 to 10 hours as the keep time at the maximum temperature. Examples of the apparatus for performing calcination and main firing include an electric furnace and a gas furnace.

  When manufacturing a honeycomb structure having a plugged portion, a conventionally known method can be used to form the plugged portion. As an example of a specific method, first, a sheet is attached to the end face of the honeycomb formed body manufactured by the above method. Next, a hole is made in the sheet at a position corresponding to the cell in which the plugging portion is to be formed. Next, with the sheet attached, the end face of the honeycomb formed body is dipped in a plugging slurry in which the plugging portion forming material is slurried, and plugged through the holes formed in the sheet. The plugging slurry is filled into the open end of the cell to be stopped. The plugging slurry thus filled is dried and then fired and cured to form a plugging portion. The plugged portions are preferably formed in such an arrangement that both end faces of the honeycomb structure exhibit a complementary checkered pattern. Moreover, it is preferable to use the same material as the forming material of the honeycomb formed body as the forming material of the plugging portion. The plugging portion may be formed at any stage after the honeycomb formed body is dried, after calcination, and after firing (main firing).

  By such a manufacturing method, the present invention in which only a specific portion where stress is concentrated when a sudden temperature change occurs is reinforced in a limited (selective) manner by thickening corners or blocking cells. This honeycomb structure is obtained.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

Example 1
As a ceramic raw material, a cordierite forming raw material (alumina, talc, kaolin) was used. The mass ratio of alumina, talc, and kaolin was the mass ratio at which cordierite was obtained after firing. The ceramic raw material was mixed with a binder (methyl cellulose) and water to obtain a ceramic forming raw material. The obtained ceramic forming raw material was kneaded using a kneader to obtain clay.

  Next, the obtained kneaded material was extruded into a honeycomb shape to obtain a honeycomb formed body. In this extrusion molding, a general die that does not support the thickening of a predetermined corner portion was used. The honeycomb formed body thus obtained was dried with a microwave dryer and further dried with a hot air dryer to obtain a dried honeycomb body.

  Next, among the imperfect cells of the honeycomb dried body, triangular incomplete cells at least part of which are included in the rotation region, and the cross-sectional shape of the complete cell passes through the center of gravity of the end face of the honeycomb dried body. A square-shaped line extending in the diagonal direction was filled with a filler made of the same material as the forming raw material, and the triangular imperfect cell was closed over the entire length.

Thus, after drying the filler filled in the predetermined triangular imperfect cells, the dried honeycomb body was calcined (degreasing) at 550 ° C. for 3 hours in an air atmosphere. Thereafter, the honeycomb structure of Example 1 was obtained by firing at about 1400 ° C. to 1500 ° C. for 2 hours. This honeycomb structure is a triangular incomplete cell including at least a part thereof in the rotation region, and extends in the diagonal direction of a square that is a complete cell cross-sectional shape through the center of gravity of the end face of the honeycomb structure. Only what exists on the straight line is obstructed over its entire length. Further, this honeycomb structure has a circular outer peripheral shape of a cross section perpendicular to the length direction, and a diameter of the cross section is 143.8 mm. This honeycomb structure has a length of 152.4 mm, a complete cell shape of a square, a cell density of 46.5 cells / cm ² , a partition wall thickness of 305 μm, a partition wall porosity of 52%, and a partition wall The average pore diameter is 13 μm.

(Example 2)
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Example 2. This honeycomb structure has an obtuse angle among the corners formed at the intersections of the partition walls and the outer peripheral wall that define the triangular imperfect cells that include at least a part thereof in the rotation region. Only the corners are thickened to have an R shape. R (radius of curvature) in the R shape was 100 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Example 3)
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Example 3. This honeycomb structure is a corner formed at the intersection of a partition wall and an outer peripheral wall forming a triangular imperfect cell that includes at least a part of the rotation area, and the angle is an obtuse angle. Both the one and the acute angle are thickened so as to have an R shape. R (radius of curvature) in the R shape was 100 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

Example 4
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Example 4. This honeycomb structure has an obtuse angle among the corners formed at the intersections of the partition walls and the outer peripheral wall that define the triangular imperfect cells that include at least a part thereof in the rotation region. Only the corners are thickened so as to have a C-plane shape. C in the C shape was 70 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Example 5)
Of the imperfect cells of the dried honeycomb body obtained in the same manner as in Example 1, the triangular imperfect cells at least part of which are included in the rotation region are filled with a filler made of the same material as the forming raw material, The triangular incomplete cell was blocked over the entire length. Thus, after drying the filler filled in the predetermined triangular imperfect cells, this honeycomb dried body was calcined and fired in the same manner as in Example 1 to obtain the honeycomb structure of Example 5. It was. In this honeycomb structure, only the triangular incomplete cells including at least a part thereof in the rotation region are closed over the entire length. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Example 6)
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Example 6. This honeycomb structure has an obtuse angle among the corners formed at the intersections of the partition walls and the outer peripheral wall that define the triangular imperfect cells that include at least a part thereof in the rotation region. Only the corners are thickened to have an R shape. R (curvature radius) in the R shape was 80 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Example 7)
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Example 7. This honeycomb structure has an obtuse angle among the corners formed at the intersections of the partition walls and the outer peripheral wall that define the triangular imperfect cells that include at least a part thereof in the rotation region. Only the corners are thickened so as to have a C-plane shape. C in the C shape was 55 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Example 8)
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Example 8. This honeycomb structure has an obtuse angle among the corners formed at the intersections of the partition walls and the outer peripheral wall that define the triangular imperfect cells that include at least a part thereof in the rotation region. Only the corners are thickened so as to have an inverted R shape. R (curvature radius) in the inverted R shape was 50 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Comparative Example 1)
A honeycomb dried body was obtained in the same manner as in Example 1. This honeycomb dried body was calcined and fired in the same manner as in Example 1 without filling any cells with a filler to obtain a honeycomb structure of Comparative Example 1. This honeycomb structure is a normal honeycomb structure in which predetermined corner portions are not thickened and predetermined triangular imperfect cells are not blocked. The outer peripheral shape of the cross section perpendicular to the length direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Comparative Example 2)
Of the incomplete cells of the dried honeycomb body obtained in the same manner as in Example 1, all incomplete cells (including incomplete cells other than triangular incomplete cells) including at least a part thereof in the rotation region are included. The filler made of the same material as the forming raw material was filled, and the incomplete cell was closed over the entire length. Thus, after the filler filled in the predetermined incomplete cells was dried, this honeycomb dried body was calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Comparative Example 2. In this honeycomb structure, all incomplete cells (including incomplete cells other than triangular incomplete cells) including at least a part thereof in the rotation region are closed over the entire length. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Comparative Example 3)
All the incomplete cells (including incomplete cells not entirely included in the rotation region) of the dried honeycomb body obtained in the same manner as in Example 1 were filled with the filler made of the same material as the forming raw material. The incomplete cell was blocked over its entire length. Thus, after the filler filled in the incomplete cells was dried, this honeycomb dried body was calcined and fired in the same manner as in Example 1 to obtain the honeycomb structure of Comparative Example 3. In this honeycomb structure, all incomplete cells (including incomplete cells not entirely included in the rotation region) are closed over the entire length. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Comparative Example 4)
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Comparative Example 4. This honeycomb structure is formed at the intersection of a partition wall and an outer peripheral wall forming incomplete cells (including incomplete cells other than triangular incomplete cells) including at least a part thereof in the rotation region. All the corners are thickened so as to have an R shape. R (radius of curvature) in the R shape was 100 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Comparative Example 5)
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Comparative Example 5. This honeycomb structure has an acute angle among the corners formed at the intersections of the partition walls and the outer peripheral wall that define the triangular imperfect cells that include at least a part thereof in the rotation region. Only the corners are thickened to have an R shape. R (radius of curvature) in the R shape was 100 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Comparative Example 6)
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Comparative Example 6. In this honeycomb structure, corners formed at the intersections of the partition walls and the outer peripheral wall that define all incomplete cells (including incomplete cells not entirely included in the rotation region), All of them are thickened so as to have an R shape. R (radius of curvature) in the R shape was 100 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Comparative Example 7)
The kneaded material produced in the same manner as in Example 1 was extruded into a honeycomb shape using a die whose portion corresponding to the corner portion to be thickened had a shape corresponding to the thickened state. Molded to obtain a honeycomb molded body. The honeycomb formed body thus obtained was dried, calcined and fired in the same manner as in Example 1 to obtain a honeycomb structure of Comparative Example 7. This honeycomb structure is thick so that the corners formed at the intersections of the partition walls that form incomplete cells that are not entirely included in the rotation region and the outer peripheral wall have an R shape. It has been R (radius of curvature) in the R shape was 100 μm. Further, the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure is circular, and the diameter of the cross section is the same as that of the honeycomb structure of Example 1. Further, the length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are also the same as those of the honeycomb structure of Example 1.

(Evaluation)
The honeycomb structures of Examples 1 to 8 and Comparative Examples 1 to 7 were evaluated for electric furnace spalling properties (ESP) and pressure loss by the following methods, and the results are shown in Table 1 and FIG.

[Evaluation of electric furnace spalling (ESP)]
Place the honeycomb structure at room temperature in an electric furnace maintained at a predetermined temperature higher than room temperature, hold it for 20 minutes, take the honeycomb structure on a refractory brick, let it stand for more than 15 minutes, and cool it to room temperature. The honeycomb structure was examined for cracks. This operation was repeated until cracks occurred in the honeycomb structure. The temperature in the electric furnace was increased by 50 ° C. each time the above operation was repeated. The temperature inside the electric furnace in the operation one time before the operation in which cracks were confirmed in the honeycomb structure was taken as the safe temperature of the honeycomb structure. Then, based on the safety temperature of the honeycomb structure of Comparative Example 1 (a normal honeycomb structure in which predetermined corners are not thickened and predetermined triangular imperfect cells are not blocked), the implementation is performed on that basis. The increase rate of the safe temperature of the honeycomb structures of Examples 1 to 8 and Comparative Examples 2 to 7 was calculated. It can be said that the higher the rate of increase, the higher the thermal shock resistance.

[Evaluation of pressure loss]
Under room temperature conditions, air was passed through the honeycomb structure at a flow rate of 10 m ³ / min, and pressure was measured on the inlet side and the outlet side of the honeycomb structure. The pressure difference between the pressure on the inlet side and the pressure on the outlet side measured in this way was defined as the pressure loss of the honeycomb structure. Then, on the basis of the pressure loss of the honeycomb structure of Comparative Example 1 (a normal honeycomb structure in which the predetermined corners are not thickened and the predetermined triangular imperfect cells are not blocked), the implementation is performed on the pressure loss The increase rate of the pressure loss of the honeycomb structures of Examples 1 to 8 and Comparative Examples 2 to 7 was calculated. It can be said that the lower the rate of increase, the smaller the influence on the internal combustion engine such as the engine (deterioration of fuel consumption, etc.).

(Discussion)
As shown in Table 1 and FIG. 10, the honeycomb structures of Examples 1 to 8, which are examples of the present invention, although compared with the honeycomb structure of Comparative Example 1, hardly increased in pressure loss. It was confirmed that ESP was improved. On the other hand, in the honeycomb structures of Comparative Examples 2 to 7 not included in the present invention, it is confirmed that the pressure loss is significantly increased or the ESP is equal to or less than that of the honeycomb structure of Comparative Example 1. It was done.

Example 9
A honeycomb structure of Example 9 was obtained in the same manner as Example 1 except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). Note that the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, has a major axis of 198.3 mm and a minor axis of 102.2 mm. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Example 10)
A honeycomb structure of Example 10 was obtained in the same manner as Example 2 except that the outer peripheral shape of the cross section perpendicular to the length direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Example 11)
A honeycomb structure of Example 11 was obtained in the same manner as Example 3 except that the outer peripheral shape of the cross section perpendicular to the length direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Example 12)
A honeycomb structure of Example 12 was obtained in the same manner as Example 4 except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Example 13)
A honeycomb structure of Example 13 was obtained in the same manner as Example 6 except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Example 14)
A honeycomb structure of Example 14 was obtained in the same manner as Example 7, except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Example 15)
A honeycomb structure of Example 15 was obtained in the same manner as Example 8, except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Comparative Example 8)
A honeycomb structure of Comparative Example 8 was obtained in the same manner as Comparative Example 1 except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Comparative Example 9)
A honeycomb structure of Comparative Example 9 was obtained in the same manner as Comparative Example 2 except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Comparative Example 10)
A honeycomb structure of Comparative Example 10 was obtained in the same manner as Comparative Example 3 except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Comparative Example 11)
A honeycomb structure of Comparative Example 11 was obtained in the same manner as Comparative Example 4 except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Comparative Example 12)
A honeycomb structure of Comparative Example 12 was obtained in the same manner as Comparative Example 6 except that the outer peripheral shape of the cross section perpendicular to the longitudinal direction was an oval (oval shape). The major axis and the minor axis of the oval, which is the outer peripheral shape of the cross section perpendicular to the longitudinal direction of the honeycomb structure, are the same as those of the honeycomb structure of Example 9. The length of the honeycomb structure, the cell shape of the complete cell, the cell density, the partition wall thickness, the partition wall porosity, and the partition wall average pore diameter are the same as those of the honeycomb structure of Example 1.

(Evaluation)
For the honeycomb structures of Examples 9 to 15 and Comparative Examples 8 to 12, electric furnace spalling (ESP) and pressure loss were evaluated in the same manner as described above, and the results are shown in Table 2 and FIG. Indicated. However, in the evaluation of the electric furnace spalling property (ESP), the safety temperature of the honeycomb structures of Examples 9 to 15 and Comparative Examples 9 to 12 was compared with the safety temperature of the honeycomb structure of Comparative Example 8 as a reference. The rate of increase was calculated. Similarly, in the evaluation of the pressure loss, the pressure loss of the honeycomb structure of Comparative Example 8 was used as a reference, and the increase rate of the pressure loss of the honeycomb structures of Examples 9 to 15 and Comparative Examples 9 to 12 was calculated. .

(Discussion)
As shown in Table 2 and FIG. 11, the honeycomb structures of Examples 9 to 15, which are examples of the present invention, are not related to the honeycomb structure of Comparative Example 8 although the pressure loss is hardly increased. It was confirmed that ESP was improved. On the other hand, in the honeycomb structures of Comparative Examples 9 to 12 not included in the present invention, it was confirmed that the pressure loss was significantly increased or the ESP was equal to or less than that of the honeycomb structure of Comparative Example 8. It was done.

  INDUSTRIAL APPLICABILITY The present invention can be used for a catalyst carrier in an exhaust gas purification catalytic converter, a particulate collection filter such as DPF, and the like.

1: honeycomb structure, 3: partition wall, 4: outer peripheral wall, 5: complete cell, 6: incomplete cell, 6a: incomplete cell with triangular cross section (triangular incomplete cell), 6b: cross sectional shape Are not triangular (incomplete cells other than triangular incomplete cells), 8: corner, 8a: corner (angle where the angle is an obtuse angle), 8b: corner (the angle is acute) 10: end face, 11: end face, 12: filler, 20a, 20b, 20c, 20d: rotation region, G: center of gravity, S, S1, S2, S3: line segment.

Claims (5)

A porous partition wall defining a plurality of cells communicating between two end faces, and an outer peripheral wall formed integrally with the partition wall, and the outer peripheral shape of the cross section perpendicular to the length direction is curved Is a shape including
The cell is composed of a complete cell having a perfect cell cross section of a quadrangle, and an incomplete cell having an incomplete cross section without forming a quadrangle because a part thereof is in contact with the outer peripheral wall,
At least a part of a straight line extending in a diagonal direction of a quadrangle that is a cross-sectional shape of the complete cell through the center of gravity of the end face is rotated within a range of ± 5 ° about the center of gravity as a rotation center. Of the corners formed at the intersections of the partition walls forming the incomplete cells having a triangular cross-sectional shape and the outer peripheral wall, at least the angle is an obtuse angle A honeycomb structure that is thickened so that the corners have any shape selected from the group consisting of an R shape, an inverted R shape, and a C-plane shape.   Only the corner of which the angle is an obtuse angle is thickened so as to have any shape selected from the group consisting of an R shape, an inverted R shape, and a C surface shape. 2. The honeycomb structure according to 1.   The honeycomb structure according to claim 1 or 2, wherein a plugging member that plugs one open end of a predetermined cell and plugs the other open end of the remaining cell is formed. A porous partition wall defining a plurality of cells communicating between two end faces, and an outer peripheral wall formed integrally with the partition wall, and the outer peripheral shape of the cross section perpendicular to the length direction is curved Is a shape including
The cell is composed of a complete cell having a perfect cell cross section of a quadrangle, and an incomplete cell having an incomplete cross section without forming a quadrangle because a part thereof is in contact with the outer peripheral wall,
At least a part of a straight line extending in a diagonal direction of a quadrangle that is a cross-sectional shape of the complete cell through the center of gravity of the end face is rotated within a range of ± 5 ° about the center of gravity as a rotation center. A honeycomb structure in which an incomplete cell whose cross-sectional shape is triangular is closed over its entire length.   Plugging one open end of a given cell and plugging the other open end of the remaining cell except for the incomplete cell blocked over its entire length The honeycomb structure according to claim 4, wherein the member is formed.

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