JP2012106222A - Honeycomb structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a honeycomb structure where filling of a sealing material paste for sealing a cell is easily carried out; the cell cracks and the like are unlikely to occur; and the aperture ratio is high.SOLUTION: The honeycomb structure includes a ceramic block composed of a honeycomb burned substance where a large number of cells are disposed in parallel in a longitudinal direction separated from a cell wall and where an outer peripheral wall is formed on the outer periphery thereof. The cells include: an outer peripheral cell adjacent to the outer peripheral wall of the honeycomb burned substance comprising the outer periphery of the ceramic block; and a basic cell disposed inside from the outer peripheral cell. The outer peripheral cell includes a deformation cell whose shape of the cross section perpendicular to the longitudinal direction is different from that of the basic cell. The deformation cell is the cell in which a circle of 0.90 mm in diameter could be inserted inside the shape of the cross section perpendicular to the longitudinal direction.

Description

The present invention relates to a honeycomb structure.

Particulates such as soot (hereinafter also referred to as PM) and other harmful components contained in exhaust gas discharged from internal combustion engines such as vehicles such as buses and trucks or construction machinery may cause harm to the environment and the human body. It has become a problem recently. Accordingly, various honeycomb structures made of porous ceramics have been proposed as honeycomb filters for collecting PM in exhaust gas and purifying the exhaust gas.

Conventionally known as such a honeycomb structure is a honeycomb structure comprising ceramic blocks in which a plurality of honeycomb fired bodies having a large number of cells are bundled (Patent Document 1). Among the honeycomb fired bodies used when manufacturing the conventional honeycomb structure described in Patent Document 1, examples of the honeycomb fired bodies located at the outermost peripheral portion of the honeycomb structure are shown in FIGS. This is schematically shown in b). In the honeycomb fired body 1110 and the honeycomb fired body 1120 shown in FIGS. 11 (a) and 11 (b), the cell 1111 and the cell 1121 that are closest to the curved surface constituting the outer peripheral surface of the ceramic block are perpendicular to the longitudinal direction. (Hereinafter, also simply referred to as a cross-sectional shape) is substantially triangular or substantially trapezoidal, unlike the cross-sectional shape of the cells located inside the cells, and one side of the cells 1111 and 1121 is formed along the curved surface. Has been.

Further, in Patent Literature 1, in the cells of the honeycomb fired body, the cells are not formed in the vicinity of the outer peripheral wall of the fired body constituting the outer periphery of the ceramic block among the fired body outer peripheral walls of the honeycomb fired body, and the sealing material paste is filled. An easy honeycomb structure has also been proposed. FIGS. 12A and 12B show a honeycomb fired body constituting a conventional honeycomb structure in which no cells are formed in the vicinity of a fired body outer peripheral wall (hereinafter also referred to as a block outer peripheral wall) constituting the outer periphery of the ceramic block. Each body example is shown. The shapes of the honeycomb fired body 1130 and the honeycomb fired body 1140 are the same as the shapes of the honeycomb fired body 1110 and the honeycomb fired body 1120 shown in FIGS. 11A and 11B, respectively. The cross-sectional shapes of the cells 1131 of the honeycomb fired body 1130 and the cells 1141 of the honeycomb fired body 1140 are substantially square, and cells are formed in the vicinity of the block outer peripheral wall 1134 or 1144 constituting the outer periphery of the ceramic block. It has not been.

Further, in the honeycomb fired body cell, the cross-sectional shape of a cell (hereinafter also referred to as a cell located at the outermost peripheral portion) in contact with the block outer peripheral wall constituting the outer periphery of the ceramic block among the outer peripheral walls of the honeycomb fired body And a honeycomb structure that has the same cross-sectional shape of cells located outside the outermost peripheral portion and facilitates filling with a plug paste (Patent Document 2). 13 (a) and 13 (b), the honeycomb fired body constituting the conventional honeycomb structure in which the cross-sectional shape of the cell located at the outermost peripheral portion is the same as the cross-sectional shape of the cell located outside the outermost peripheral portion. Each body example is shown. The cross-sectional shapes of the cells 1151 of the honeycomb fired body 1150 and the cells 1161 of the honeycomb fired body 1160 are all substantially square, and the positions of the cells 1151 or 1161 are designed so that the cells 1151 or 1161 are arranged at equal intervals. ing. Then, in order to make the cross-sectional shape of the cell located at the outermost peripheral portion the same as the cross-sectional shape of the cell located outside the outermost peripheral portion, the fired body outer peripheral wall 1154 of the honeycomb fired body 1150 or the firing of the honeycomb fired body 1160 The body outer peripheral wall 1164 is provided with a step corresponding to the position of the cell 1151 or the cell 1161 located at the outermost peripheral portion.

JP 2004-154718 A International Publication No. 2008/126335 Pamphlet

When sealing the cells 1111 of the honeycomb fired body 1110 and the cells 1121 of the honeycomb fired body 1120 constituting the conventional honeycomb structure described in Patent Document 1, the cell opening area is small, It may be difficult to fill the material paste, or the sealing material may leak and / or protrude, which may result in insufficient sealing of the cells.

When a honeycomb structure manufactured using a honeycomb fired body with insufficient cell sealing is used as an exhaust gas purification filter, the exhaust gas flowing into the honeycomb structure flows out of the same cell without passing through the cell wall. Therefore, there is a problem that it does not function as a filter.

According to the conventional honeycomb structure formed of the honeycomb fired body shown in FIGS. 12A and 12B, there is no cell that has conventionally had a small opening area and has been difficult to fill with the sealing material paste. Therefore, the filling with the plug material paste is facilitated, and the manufacturing efficiency of the honeycomb structure is improved.

However, in such a conventional honeycomb structure, since the aperture ratio of the whole honeycomb structure becomes low, PM is sufficiently higher than that of the conventional honeycomb structure shown in FIGS. 11 (a) and 11 (b). There is a problem that it cannot be collected.

According to the conventional honeycomb structure including the honeycomb fired body shown in FIGS. 12A and 12B, the outermost peripheral cell, which has been difficult to be filled with the sealing material paste because the opening area is small in the past, is also included. The open area is the same as the open area of cells other than the outermost peripheral cell. Therefore, the filling of the sealing material paste is facilitated and the manufacturing efficiency of the honeycomb structure is improved, but the aperture ratio of the honeycomb structure is lowered, so that the conventional structure shown in FIGS. 11 (a) and 11 (b) is used. Compared to the honeycomb structure, there is a problem that PM cannot be sufficiently collected.

Further, in the honeycomb fired body constituting the conventional honeycomb structure described in Patent Document 2, a step is provided on the outer peripheral wall of the honeycomb fired body. That is, on the outer peripheral wall of such a honeycomb fired body, as shown in FIGS. 13 (a) and 13 (b), a step consisting of a convex portion 1155 and a concave portion 1156, or a convex portion 1165 and a concave portion 1166 is formed. A step is provided.
With respect to the honeycomb fired body having such a shape, a honeycomb formed body is produced by extruding the wet mixture. In the drying process, the firing process, the honeycomb structure assembling process, and the like after the extrusion molding. In addition, a molding failure such as a convex corner existing on the outer peripheral wall of the honeycomb molded body due to contact with a jig or the like, or a crack in the concave corner due to expansion and contraction of the honeycomb molded body and the honeycomb fired body, etc. Will occur. Thereby, the manufacturing efficiency of the honeycomb structure is reduced.

Furthermore, when a honeycomb structure is manufactured using such a honeycomb fired body, convex portions and concave portions still exist on the outer peripheral portion of the manufactured honeycomb structure. Therefore, when this honeycomb structure is used as a honeycomb filter, defects such as chipping and / or cracks occur in the outer peripheral portion of the honeycomb structure due to expansion and contraction of the honeycomb fired body when exposed to a high temperature. There is also a problem that it is easy.

The present invention has been made to solve the above-described problem, and is easy to fill with a sealing material paste for sealing cells, is less likely to cause chipping, and has a high aperture ratio. An object is to provide a structure.

In order to achieve the above object, the honeycomb structure according to claim 1 is composed of a honeycomb fired body in which a large number of cells are arranged in parallel in the longitudinal direction with a cell wall therebetween and an outer peripheral wall is formed on the outer periphery. A honeycomb structure made of ceramic blocks,
The cell comprises an outer peripheral cell in contact with the outer peripheral wall of the honeycomb fired body constituting the outer periphery of the ceramic block, and a basic cell located on the inner side of the outer peripheral cell,
The outer peripheral cell includes a deformed cell having a cross-sectional shape perpendicular to the longitudinal direction different from the basic cell,
The deformation cell is a cell in which a circle having a diameter of 0.90 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction.

In the honeycomb structure according to claim 1, the outer peripheral cell includes a deformed cell having a cross-sectional shape perpendicular to the longitudinal direction different from that of the basic cell, and the deformed cell has a diameter of 0.00 in the cross-sectional shape perpendicular to the longitudinal direction. A 90 mm circle can be inserted into the cell.
Conventionally, the outer peripheral cells of the outer honeycomb fired body include small deformed cells having a small opening area in which a circle having a diameter of 0.90 mm cannot be inserted, which makes it difficult to fill the sealing material paste. Or the sealing material may easily leak or protrude, which may result in insufficient cell sealing.
However, in the honeycomb structure according to the first aspect, the deformation cells are all deformation cells having a relatively large opening area into which a circle having a diameter of 0.90 mm can be inserted, and the others are composed of basic cells. It is easy to fill the sealing material paste, the sealing material is less likely to leak and protrude, and the deformed cell can be sealed well. Therefore, defective cells that do not function as a honeycomb filter such as PM collection are unlikely to occur, and the honeycomb structure of the present invention has a function such as PM collection required for a honeycomb structure used as a honeycomb filter. Can be performed satisfactorily.

Further, in the honeycomb structure according to claim 1, not all of the deformed cells are filled, and a cell in which a circle having a diameter of 0.90 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction is provided with a filter. Since it functions as a constituting cell, the aperture ratio of the entire honeycomb structure can be kept high, and PM can be sufficiently collected.

Further, in the honeycomb structure according to claim 1, since the deformed cells exist on the outer periphery of the ceramic block, the protrusions in the shape of the outer periphery of the ceramic block are gentle as compared with the case where the outer peripheral cells are all composed of basic cells. Due to the shape, stress concentration is less likely to occur when exposed to high temperatures, and chipping is less likely to occur at the convex corners.

The deformed cell is preferably a cell in which a circle having a diameter of 1.57 mm cannot be inserted inside the cross-sectional shape perpendicular to the longitudinal direction. In the case of a deformed cell having a large cross-sectional area into which a 1.57 mm circle can be inserted, the mechanical strength is insufficient because the cell cross-section is too large.

In this specification, the cell wall of the honeycomb fired body refers to a portion that exists between two cells and separates the two cells. In the present specification, the outer peripheral wall of the honeycomb fired body refers to a portion of the wall that exists around the honeycomb fired body and forms the outer periphery of the honeycomb fired body.

In this specification, the basic cell refers to a cell of one type (same shape) or a combination of a plurality of different shapes when the cells constituting the honeycomb fired body are observed in a cross section perpendicular to the longitudinal direction. Is a minimum unit cell formed by repeating a certain number of times in the vertical and horizontal directions. For example, in the outer honeycomb fired body 120 shown in FIGS. 3A and 3B, substantially square figures are repeated in a cross section perpendicular to the longitudinal direction of the outer honeycomb fired body. In this case, a substantially square cell is referred to as a basic cell. For example, in the inner honeycomb fired body 310 shown in FIG. 7B, two types of cells having different cell cross-sectional areas are repeated. In this case, the two types of cells having different cell cross-sectional areas are collectively referred to as a basic cell. However, for convenience, one of the two types of cells having different cell cross-sectional areas may be referred to as a basic cell.
In this specification, the basic formation pattern refers to the shape of the basic cell.

In the present specification, a deformed cell is a kind of outer peripheral cell in contact with the outer peripheral wall of the outer honeycomb fired body, and the cells constituting the outer honeycomb fired body are observed in a cross section perpendicular to the longitudinal direction. A cell having a partially lacking shape compared to the shape of the basic cell and having a cell cross-sectional area smaller than the cell cross-sectional area of the basic cell. When the basic cell is one type of cell, a cell having a smaller cross-sectional area than the basic cell is referred to as a deformed cell. Further, in the outer honeycomb fired body in which the basic cell is a repeated pattern in which two or more types of cells having different cell cross-sectional areas are combined, for example, a cell smaller than a cell having a relatively large cell cross-sectional area A cell having a cross-sectional area or a cell having a smaller cross-sectional area than a cell having a relatively small cell cross-sectional area is referred to as a deformed cell. A deformed cell is also called an incomplete cell.

In the honeycomb structure according to claim 2, the deformed cell is a cell in which a circle having a diameter of 0.95 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction.

In the honeycomb structure according to claim 2, the deformed cell is a cell in which a circle having a diameter of 0.95 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction, and the opening area becomes larger. The deformed cell can be sealed, and functions such as PM collection required for a honeycomb structure used as a honeycomb filter can be more satisfactorily performed.
In the honeycomb structure according to the second aspect, the opening ratio of the entire honeycomb structure can be kept higher, and PM can be sufficiently collected.
Furthermore, in the honeycomb structure according to claim 2, the protrusions on the shape of the outer periphery of the ceramic block have a gentle shape, stress concentration is difficult to occur when exposed to high temperatures, and the convex corners are chipped. It becomes difficult to do.

In the honeycomb structure according to claim 3, the outer peripheral wall constituting the outer periphery of the ceramic block has a cross-sectional shape perpendicular to the longitudinal direction of the honeycomb fired body, and a circle having a diameter of 0.90 mm cannot be inserted therein. This includes a peripheral wall completely filled with the same material as the cell wall.
In the honeycomb structure according to claim 3, since the inside of the deformed small cell is completely filled when the honeycomb formed body is manufactured, it is not necessary to fill the sealing material paste. It is possible to prevent poor filling.

In the honeycomb structure according to a fourth aspect, the ceramic block is formed by binding a plurality of honeycomb fired bodies through an adhesive layer.
Thus, even when the ceramic block is formed by binding a plurality of honeycomb fired bodies through the adhesive layer, a circle having a diameter of 0.90 mm can be inserted inside the cross-sectional shape perpendicular to the longitudinal direction. Since the modified cell is provided, the same effect as in the case of the invention described in claim 1 can be obtained.

The honeycomb structure according to claim 5, wherein the ceramic block is combined with the honeycomb fired bodies having different shapes, and the outer honeycomb fired body having an outer peripheral wall constituting the outer periphery of the ceramic block and the outer Since the outer honeycomb fired body includes the above-described deformed cells, the same effect as in the case of the invention according to claim 1 can be obtained.

In the honeycomb structure according to claim 6, in addition to the deformation cells being formed, a cross-sectional shape perpendicular to the longitudinal direction of the outer peripheral wall of the honeycomb fired body constituting the outer periphery of the ceramic block is a convex portion. It is an outer peripheral wall provided with a step consisting of a concave portion, and the convex portion and / or the concave portion is constituted by a curve having a shape in which the convex portion and / or the concave portion is chamfered.
In the honeycomb structure according to claim 6, stress concentration is difficult to occur when exposed to a high temperature and the generated stress can be relieved, and the protrusions and / or the recesses are chipped and / or cracked. Can be effectively prevented from occurring.

In the present specification, chamfering is applied to the convex portion provided on the outer peripheral wall of the outer honeycomb fired body means that the cross-sectional shape of the convex portion is a shape in which the corner portion of the outer peripheral wall is cut. It means being.
On the other hand, chamfering is applied to the concave portion provided on the outer peripheral wall of the outer honeycomb fired body. The cross-sectional shape of the concave portion is the same shape as the corner portion of the outer peripheral wall being pseudo chamfered. It means that the shape is such that the corners of the outer peripheral wall are filled. For example, if the outer peripheral wall of the outer honeycomb fired body has the same shape as the shape that has been subjected to pseudo R chamfering or C chamfering, the concave portion is said to have R chamfering or C chamfering.

In the honeycomb structure according to claim 7, the convex portion and / or the concave portion has a shape in which an R chamfer is applied to the convex portion and / or the concave portion, and a curvature radius of the R chamfer is, 0.3 to 2.5 mm.
In the honeycomb structure according to claim 7, stress concentration is less likely to occur when exposed to a high temperature, the generated stress can be more effectively relaxed, and cracks and the like can be more effectively prevented. can do. When the radius of curvature of the R chamfer is less than 0.3 mm, it is difficult to more effectively relieve the stress generated by heat or the like, while when the radius of curvature of the R chamfer exceeds 2.5 mm, Processing becomes difficult.

The honeycomb structure according to claim 8, wherein a shape of a cross section perpendicular to the longitudinal direction of the outer peripheral cell excluding the deformed cell and a shape of a cross section perpendicular to the longitudinal direction of the basic cell are substantially rectangular. It is.

In the honeycomb structure according to claim 9, the outer peripheral cell excluding the deformation cell and the basic cell are composed of a large capacity cell and a small capacity cell,
The area of the cross section perpendicular to the longitudinal direction of the large capacity cell is larger than the area of the cross section perpendicular to the longitudinal direction of the small capacity cell.
In the honeycomb structure according to the ninth aspect, a large amount of PM can be collected when the honeycomb structure is used as an exhaust gas purification filter.

In the honeycomb structure according to claim 10, a shape of a cross section perpendicular to the longitudinal direction of the large-capacity cell is substantially a square, and a shape of a cross section perpendicular to the longitudinal direction of the small-capacity cell is a substantially square. .

In the honeycomb structure according to claim 11, the shape of the cross section perpendicular to the longitudinal direction of the large capacity cell is substantially octagonal, and the shape of the cross section perpendicular to the longitudinal direction of the small capacity cell is substantially square. is there.
In the honeycomb structure according to claim 11, since the cross-sectional shape of the large-capacity cell is substantially octagonal and the cross-sectional shape of the small-capacity cell is substantially square, the large-capacity cell and the small-capacity cell are arranged with good symmetry. Therefore, the cell wall is less likely to be distorted and the honeycomb structure is excellent in mechanical strength.

In the honeycomb structure according to claim 12, in the cross section perpendicular to the longitudinal direction of the large capacity cell and the small capacity cell, the shape of the cross section perpendicular to the longitudinal direction of each side of the cell is configured by a curve. Yes. Therefore, stress concentration is less likely to occur on the cell wall, and cracks and the like are less likely to occur on the cell wall.

In the honeycomb structured body according to claim 13, the thickness of the outer peripheral wall of the honeycomb fired body constituting the outer periphery of the ceramic block is larger than the thickness of the cell wall located inside the honeycomb fired body.
Further, in the honeycomb structure according to claim 14, the thickness of the outer peripheral wall of the honeycomb fired body constituting the outer periphery of the ceramic block is 1.3 to 3 times the thickness of the cell wall of the honeycomb fired body located inside. 3.0 times.
In the honeycomb structured body according to claims 13 and 14, since the thickness of the outer peripheral wall of the honeycomb fired body is thicker than the inner cell wall, the outer peripheral wall of the honeycomb fired body is generated when a compressive force or the like is generated from the outside. It becomes a honeycomb structure which is not easily destroyed and has excellent mechanical properties. When the thickness of the outer peripheral wall of the honeycomb fired body constituting the outer periphery is less than 1.3 times the thickness of the cell wall of the honeycomb fired body located inside, the mechanical strength of the outer peripheral wall of the honeycomb fired body is improved. On the other hand, if the thickness of the outer peripheral wall of the honeycomb fired body constituting the outer periphery exceeds 3.0 times the thickness of the cell wall of the honeycomb fired body positioned inside, the outer peripheral wall becomes thicker. As a result, the aperture ratio of the honeycomb structure decreases.

The honeycomb structure according to claim 15, wherein a cross section of the outer honeycomb fired body is surrounded by three straight lines and an outer peripheral wall constituting a part of the outer periphery of the ceramic block. The cross section of the inner honeycomb fired body is a substantially square unit in which the shape of the cross section perpendicular to the longitudinal direction is a substantially square shape.
In the honeycomb structure according to the fifteenth aspect, the honeycomb structure can be efficiently configured with a small number of honeycomb fired bodies by combining the substantially sectional fan unit and the substantially rectangular unit. For this reason, the honeycomb structure can be easily manufactured, and the manufacturing cost can be reduced.

In the honeycomb structure according to the sixteenth aspect, one end of each of the cells is alternately sealed. Therefore, the honeycomb structure functions as a filter.
In the honeycomb structure according to claim 17, a coat layer is formed on the outer peripheral surface of the ceramic block.

FIG. 1 is a perspective view schematically showing a honeycomb structure according to the first embodiment of the present invention. Fig. 2 (a) is a perspective view schematically showing an inner honeycomb fired body in the honeycomb structure of the first embodiment of the present invention, and Fig. 2 (b) is an inner view shown in Fig. 2 (a). It is a BB line sectional view of a honeycomb fired body. Fig. 3 (a) is a perspective view schematically showing an outer honeycomb fired body in the honeycomb structure of the first embodiment of the present invention, and Fig. 3 (b) is an outer view shown in Fig. 3 (a). It is sectional drawing which shows typically the end surface vicinity of a honeycomb fired body. FIG. 4 is a cross-sectional view of the honeycomb structure shown in FIG. 1 taken along the line AA. FIG. 5 is a cross-sectional view of the honeycomb structure according to the second embodiment of the present invention. Fig. 6 (a) is a cross-sectional view schematically showing the vicinity of the end face of the outer honeycomb fired body constituting the honeycomb structure of the second embodiment of the present invention, and Fig. 6 (b) is a diagram of the present invention. FIG. 6 is a cross-sectional view schematically showing the vicinity of the end face of another outer honeycomb fired body constituting the honeycomb structure of the second embodiment. FIG. 7A is a cross-sectional view schematically showing the vicinity of the end face of the outer honeycomb fired body constituting the honeycomb structure of the third embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view schematically showing the vicinity of an end face of an inner honeycomb fired body constituting the honeycomb structure of the third embodiment. Fig. 8 (a) is a cross-sectional view schematically showing the honeycomb structured body of the fourth embodiment of the present invention, and Fig. 8 (b) is an external view of the honeycomb structured body shown in Fig. 8 (a). Fig. 8C is a cross-sectional view schematically showing the vicinity of the end face of the honeycomb fired body, and Fig. 8C is a schematic view of the vicinity of the end face of another outer honeycomb fired body constituting the honeycomb structure shown in Fig. 8A. FIG. FIG. 9 is a cross-sectional view of a honeycomb structure according to still another embodiment of the present invention. FIG. 10 is a graph illustrating the diameter of an insertable circle and the sealing failure rate in Examples 1 to 4 and Comparative Examples 1 to 4. Fig. 11 (a) is a perspective view schematically showing an example of a honeycomb fired body constituting a conventional honeycomb structure, and Fig. 11 (b) shows another honeycomb fired body constituting the conventional honeycomb structure. It is a perspective view which shows an example typically. Fig. 12 (a) is a perspective view schematically showing an example of a honeycomb fired body constituting a conventional honeycomb structure, and Fig. 12 (b) shows another honeycomb fired body constituting the conventional honeycomb structure. It is a perspective view which shows an example typically. FIG. 13 (a) is a perspective view schematically showing an example of a honeycomb fired body constituting the conventional honeycomb structure, and FIG. 13 (b) is another view of the honeycomb fired body constituting the conventional honeycomb structure. It is a perspective view which shows an example typically.

The honeycomb structure of the present invention is a honeycomb structure made of a ceramic block composed of a honeycomb fired body in which a large number of cells are arranged in parallel in the longitudinal direction across a cell wall, and an outer peripheral wall is formed on the outer periphery.
The cell comprises an outer peripheral cell in contact with the outer peripheral wall of the honeycomb fired body constituting the outer periphery of the ceramic block, and a basic cell located on the inner side of the outer peripheral cell,
The outer peripheral cell includes a deformed cell having a cross-sectional shape perpendicular to the longitudinal direction different from the basic cell,
The deformation cell is a cell in which a circle having a diameter of 0.90 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction.

In the ceramic block, it is desirable that a plurality of honeycomb fired bodies are bundled through an adhesive layer, and the ceramic block is formed by combining the honeycomb fired bodies having different shapes, and It is desirable that the outer honeycomb fired body having an outer peripheral wall constituting the outer periphery and the inner honeycomb fired body positioned on the inner side of the outer honeycomb fired body.
Hereinafter, specific embodiments of the honeycomb structure will be described.

(First embodiment)
A first embodiment of a honeycomb structure of the present invention will be described with reference to the drawings.
In this specification, when a section of a honeycomb structure, a section of a honeycomb fired body, or a section of a honeycomb formed body is simply described, a section perpendicular to the longitudinal direction of the honeycomb structure, respectively, a longitudinal direction of the honeycomb fired body Or a cross section perpendicular to the longitudinal direction of the honeycomb formed body.
Further, in this specification, when simply expressed as a cross-sectional area of a honeycomb fired body, it indicates a cross-sectional area of a cross section perpendicular to the longitudinal direction of the honeycomb fired body.

FIG. 1 is a perspective view schematically showing a honeycomb structure according to the first embodiment of the present invention. Fig.2 (a) is a perspective view which shows typically the inner honeycomb fired body which comprises the honeycomb structure of 1st embodiment of this invention, FIG.2 (b) is shown to Fig.2 (a). It is a BB line sectional view of an inner honeycomb fired body. Fig. 3 (a) is a perspective view schematically showing an outer honeycomb fired body constituting the honeycomb structure of the first embodiment of the present invention, and Fig. 3 (b) is shown in Fig. 3 (a). It is sectional drawing which shows typically the end surface vicinity of an outer honeycomb fired body. FIG. 4 is a cross-sectional view of the honeycomb structure shown in FIG. 1 taken along the line AA.

In the honeycomb structure 100 shown in FIGS. 1 and 4, eight outer honeycomb fired bodies 120 having a shape as shown in FIGS. 3A and 3B, and FIG. , (B) four inner honeycomb fired bodies 110 having a shape as shown in FIG. 6 are bonded together via an adhesive layer 101 (101A to 101D) to form a ceramic block 103. A coat layer 102 is formed on the outer periphery.
The cross-sectional shape of the inner honeycomb fired body 110 is substantially square.
As shown in FIG. 4, the outer honeycomb fired body 120 has a substantially fan-shaped section surrounded by three line segments 120 a, 120 b, 120 c and one substantially arc 120 d, and the three line segments Two angles (the angle formed by the line segment 120b and the line segment 120c and the angle formed by the line segment 120a and the line segment 120b) are 90 ° and 135 °, respectively. The shape of the substantially arc will be described later.

In addition, in the cross section, the honeycomb structure 100 includes an adhesive layer 101C formed in a direction from the corner portion of the central portion toward the outer peripheral side surface of the honeycomb structure 100 among the adhesive layer layers 101C and 101D of the outer peripheral portion. The adhesive layer 101D formed in a direction from the corner portion other than the central portion toward the outer peripheral side surface of the honeycomb structure 100 forms an angle of 45 °.

In the inner honeycomb fired body 110 shown in FIGS. 2 (a) and 2 (b), a large number of cells 111 are arranged in parallel in the longitudinal direction (in the direction of arrow a in FIG. 2 (a)) with a cell wall 113 therebetween. One end of the cell 111 is sealed with a sealing material 112. Therefore, the exhaust gas G (see the arrow in FIG. 2B) that flows into the cell 111 with one end face opened must always pass through the cell wall 113 separating the cell 111 and then the other cell with the other end face open. 111 flows out. Therefore, the cell wall 113 functions as a filter for collecting PM and the like.

The outer honeycomb fired body 120 shown in FIGS. 3 (a) and 3 (b) also has a large number of cells 121 arranged in parallel in the longitudinal direction across the cell wall 123, like the inner honeycomb fired body 110. One end of 121 is sealed with a sealing material 122. Therefore, the exhaust gas that has flowed into the cell 121 having one open end face always passes through the cell wall 123 separating the cells 121 and then flows out from the other cell 121 having the other end face open.
That is, the outer honeycomb fired body 120 has the same function as the inner honeycomb fired body 110, although the outer shape is different from the inner honeycomb fired body 110.

As shown in FIGS. 3A and 3B, the outer honeycomb fired body 120 has an outer peripheral wall 128 that forms the outer periphery of the ceramic block 103, and the cells 121 and 124 (124 a) of the outer honeycomb fired body 120. , 124b) includes outer peripheral cells 124a and 124b in contact with the outer peripheral wall 128 constituting the outer periphery of the ceramic block 103, and basic cells 121 located on the inner side of the outer peripheral cells 124a and 124b. The outer peripheral cells 124a and 124b of the outer honeycomb fired body 120 include a deformed cell 124a having a shape different from that of the basic cell 124b in addition to the basic cell 124b having the same cross-sectional shape as that of the basic cell 121 in the longitudinal direction. Is a cell in which a circle having a diameter of 0.90 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction. That is, in the case of a cell in which a circle having a diameter of 0.90 mm cannot be inserted, the cell is not formed, and the portion is completely filled with the same material as the cell wall, and becomes the outer peripheral wall 128 of the honeycomb fired body, That portion is deleted to form a cross-sectional recess.

A cell whose cross-sectional size perpendicular to the longitudinal direction is smaller than the substantially square (substantially square) of the inner cell, which is a basic cell, is called a deformed cell. In addition, the cross-sectional shape of the cell may include a right-angled portion, and the portion corresponding to the right-angled portion may be a circular arc (a shape in which the cell is pseudo-R chamfered) or a C-chamfered shape (the cell is simulated) C-shaped chamfered shape).

In the case of a cell in which a circle having a diameter of 0.90 mm cannot be inserted, the cell may not be formed, and the portion may be completely filled with the same material as the cell wall and may be a part of the outer peripheral wall of the honeycomb fired body. . Moreover, the part may be deleted, and the cross section of the ceramic block perpendicular to the longitudinal direction of the cell may have a concave shape. Furthermore, you may become both above-mentioned aspects. When the cross section of the ceramic block perpendicular to the longitudinal direction of the cell has a concave shape, it is simply referred to as a cross sectional concave portion.

Note that a cell into which a circle with a diameter of 0.90 mm can be inserted means that a jig with a diameter of 0.90 mm (for example, a metal rod or a ceramic rod) is actually inserted into an actual cell. It is possible to determine whether or not it can be inserted by checking whether it can be inserted or whether or not damage (cracks, cracks, etc.) occurs when it is inserted into the cell. It may be determined whether or not insertion into the cell is possible based on comparison with the dimension value of the circle. Among these, it is desirable to make a determination from the design drawing because of the ease of determination and the ease of work.

If a small deformed cell with a small opening area that cannot be inserted into a circle with a diameter of 0.90 mm is included, it may be difficult to fill the sealing material paste, or the sealing material may easily leak or protrude. As a result, cell sealing may be insufficient.
However, in the honeycomb structure 100 according to the present embodiment, the deformation cells 124a are all deformation cells having a relatively large opening area into which a circle having a diameter of 0.90 mm can be inserted, and the others are configured from the basic cells 121 and 124b. Therefore, it is easy to fill the sealing material paste, and the sealing material does not easily leak or protrude, and the deformed cell can be sealed well.

Moreover, although the cross-sectional shape perpendicular to the longitudinal direction of the outer peripheral wall 128 is described as a substantially arc shape, specifically, the step formed by the convex portion 128a and the concave portion 128b in the cross section perpendicular to the longitudinal direction of the honeycomb fired body. The cross-sectional shape of the convex portion 128a and the concave portion 128b is formed by a curved curve having a chamfered shape. The radius of curvature of the R chamfer is preferably 0.3 to 2.5 mm.

The honeycomb fired bodies 110 and 120 constituting the honeycomb structure 100 are preferably porous bodies made of silicon carbide or silicon-containing silicon carbide.

Next, a method for manufacturing a honeycomb structure according to the present embodiment will be described. The case where silicon carbide is used as the ceramic powder will be described.
(1) A forming step for producing a honeycomb formed body by extruding a wet mixture containing a ceramic powder and a binder is performed.
Specifically, first, a silicon carbide powder having a different average particle size as a ceramic powder, an organic binder, a liquid plasticizer, a lubricant, and water are mixed using a wet mixer to produce a honeycomb molded body. A wet mixture of is prepared.
Subsequently, the wet mixture is charged into an extruder. The wet mixture is put into an extruder and extruded to produce a honeycomb formed body having a predetermined shape.

Here, a honeycomb molded body having a substantially square cross section, or a cross section surrounded by three line segments and one substantially circular arc, two angles formed by two of the three line segments are 90 °. In order to produce a honeycomb molded body having a shape of 135 °, extrusion molds corresponding to the respective shapes are used.

(2) Next, the honeycomb formed body is cut into a predetermined length and dried using a microwave dryer, hot air dryer, dielectric dryer, vacuum dryer, vacuum dryer, freeze dryer, or the like. Then, a sealing step of filling a predetermined cell with a sealing material paste as a sealing material and sealing the cell is performed. At this time, since the deformed cell is also a cell in which a circle having a diameter of 0.90 mm can be inserted, the sealing operation can be performed satisfactorily.
In addition, the conditions conventionally used when manufacturing a honeycomb fired body can be applied to the conditions of the cutting process, the drying process, and the sealing process.

(3) Next, a degreasing step of heating the organic matter in the honeycomb molded body in a degreasing furnace is performed, and the honeycomb fired body is transported to the firing furnace and the firing step is performed to produce a honeycomb fired body.
In addition, as conditions of a degreasing process and a baking process, the conditions conventionally used when manufacturing a honeycomb fired body are applicable.
Through the above steps, the inner honeycomb fired body and the outer honeycomb fired body can be manufactured.

(4) Next, an adhesive paste is applied to each of the predetermined side surfaces of the inner honeycomb fired body and the outer honeycomb fired body in which predetermined ends of each cell are sealed to form an adhesive paste layer. Then, a step of laminating other honeycomb fired bodies sequentially on this adhesive paste layer is repeated to perform a binding step for producing a ceramic block in which a predetermined number of honeycomb fired bodies are bound.
Here, as the adhesive paste, for example, a paste made of an inorganic binder, an organic binder, and inorganic particles is used. The adhesive paste may further contain inorganic fibers and / or whiskers.

(5) Next, a coating layer forming step is performed in which a coating material paste is applied to the outer periphery of the substantially cylindrical ceramic block, dried and solidified to form a coating layer.
Here, as the coating material paste, the same paste as the adhesive paste is used. In addition, you may use the paste of a different composition as a coating material paste.
Note that the coat layer is not necessarily provided, and may be provided as necessary.
Through the above steps, the honeycomb structure according to the present embodiment can be manufactured.

Hereinafter, effects of the honeycomb structure according to the present embodiment will be listed.
(1) In the honeycomb structure according to the present embodiment, the outer peripheral cells of the outer honeycomb fired body include deformed cells whose cross-sectional shape perpendicular to the longitudinal direction is different from the basic cells, and the deformed cells are perpendicular to the longitudinal direction. This is a cell in which a circle having a diameter of 0.90 mm can be inserted inside the cross-sectional shape.
Therefore, it is easy to fill the sealing material paste, it is difficult for the sealing material to leak or protrude, and the deformed cell can be sealed well.
Further, in the honeycomb structure according to the present embodiment, not all of the deformed cells are filled with the same material as the cell walls or all of the modified cells are deleted, and the deformed cells constitute a filter. Therefore, the aperture ratio of the whole honeycomb structure can be kept high, and PM can be sufficiently collected.

(2) In the honeycomb structure according to the present embodiment, since deformed cells exist on the outer periphery of the ceramic block, the protrusions in the shape of the outer periphery of the ceramic block are gentle as compared with the case where the outer peripheral cells are all composed of basic cells. It becomes a shape and it becomes difficult to generate | occur | produce the chip | corner to the convex-cornered part resulting from stress concentration, such as when it contacts a jig | tool etc. or is exposed to high temperature.

(3) In the honeycomb fired body according to the present embodiment, any one end of each cell is sealed with a sealing material. Therefore, the honeycomb structure according to the present embodiment can be suitably used as a diesel particulate filter.
(4) In the honeycomb structure according to the present embodiment, the cross-sectional shape perpendicular to the longitudinal direction of the outer peripheral wall is provided with a step including a convex portion and a concave portion, and the cross-sectional shape of the convex portion and the concave portion is the convex shape. Consists of curved surfaces with rounded chamfers on the part and the concave part, so stress concentration is less likely to occur when exposed to high temperatures such as contact with jigs, etc. It is possible to effectively prevent chipping and / or cracking from occurring in the convex part and the concave part.

Examples that more specifically disclose the first embodiment of the present invention will be described below. In addition, this invention is not limited only to these Examples.

Example 1
(1) A silicon carbide coarse powder of 52.8% by weight having an average particle size of 22 μm and a silicon carbide fine powder of 22.6% by weight of an average particle size of 0.5 μm were mixed, and the resulting mixture was mixed. 2.1% by weight of acrylic resin, 4.6% by weight of organic binder (methylcellulose), 2.8% by weight of lubricant (Unilube manufactured by NOF Corporation), 1.3% by weight of glycerin, and 13.8% by weight of water Was added and kneaded to obtain a wet mixture, followed by a molding step of extrusion molding.
In this step, a raw honeycomb molded body having substantially the same shape as the inner honeycomb fired body 110 shown in FIGS. 2 (a) and 2 (b) and without cell sealing, and FIG. ) And a raw honeycomb molded body having substantially the same shape as the outer honeycomb fired body 120 shown in FIG.

(2) Next, after the raw honeycomb formed body is dried using a microwave dryer to form a dried body of the honeycomb formed body, a filling step of filling a predetermined cell with a paste having the same composition as the wet mixture Then, it was again dried using a dryer.

(3) A degreasing step of degreasing the dried honeycomb formed body at 400 ° C. was performed, and further a firing step was performed at 2200 ° C. for 3 hours under an atmospheric pressure of argon atmosphere.
As a result, the porosity was 45%, the average pore diameter was 15 μm, the size was 34.5 mm × 34.5 mm × 150 mm, the number of cells (cell density) was 300 / inch ² , and the cell wall thickness was 0.1. An inner honeycomb fired body 110 made of a porous silicon carbide sintered body having a width of 25 mm (10 mil) and a cell width of 1.42 mm, a porosity, an average pore diameter, the number of cells (cell density), and a cell wall thickness And the width of the cell is the same as that of the inner honeycomb fired body 110, and the cross section is surrounded by three line segments and one substantially arc, and two corners formed by two of the three line segments are respectively An outer honeycomb fired body 120 having a shape of 90 ° and 135 ° (line segment 120a = 20.8 mm, line segment 120b = 35.0 mm, line segment 120c = 35.7 mm) was manufactured. At this time, the deformed cell 124a is a cell in which a circle having a diameter of 0.90 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction, and a portion in which a circle having a diameter of 0.90 mm cannot be inserted is The cell portion is filled with the wet mixture to become the outer peripheral wall of the honeycomb fired body, or the portion is deleted to form a concave section.

(4) Adhesive paste is applied to predetermined side surfaces of the inner honeycomb fired body 110 and the outer honeycomb fired body 120, and four inner honeycomb fired bodies 110 and the outer By bonding 8 honeycomb fired bodies 120 so that the arrangement shown in FIG. 1 is obtained, and further solidifying the adhesive paste at 180 ° C. for 20 minutes, the thickness of the adhesive layer is 1 mm and cylindrical. The ceramic block 103 was produced.
Here, as the adhesive paste, 30.0% by weight of silicon carbide particles having an average particle diameter of 0.6 μm, 21.4% by weight of silica sol (solid content of 30% by weight), 8.0% by weight of carboxymethylcellulose, and water An adhesive paste consisting of 40.6% by weight was used.

(5) A coating material paste layer was formed on the outer periphery of the ceramic block 103 using the adhesive paste used in the step (4) as a coating material paste. Thereafter, this coating material paste layer was dried at 120 ° C. to produce a cylindrical honeycomb structure 100 having a diameter of 143.8 mm and a length of 150 mm, in which the coating layer 102 was formed on the outer periphery.

(Example 2)
When manufacturing the outer honeycomb fired body 120, the deformable cell 124a is a cell in which a circle having a diameter of 0.95 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction, and a circle having a diameter of 0.95 mm cannot be inserted. Change the shape of the mold for extrusion so that all the cells are filled with the wet mixture and become the outer peripheral wall of the honeycomb fired body, or the part is deleted and becomes a cross-sectional recess, A honeycomb structure was manufactured in the same manner as in Example 1 except that a honeycomb formed body for the outer honeycomb fired body 120 was manufactured.

(Comparative Example 1)
When manufacturing the outer honeycomb fired body 120, the deformable cell 124a is a cell in which a circle having a diameter of 0.85 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction, and a circle having a diameter of 0.85 mm cannot be inserted. Change the shape of the mold for extrusion so that all the cells are filled with the wet mixture and become the outer peripheral wall of the honeycomb fired body, or the part is deleted and becomes a concave section in the cross section. A honeycomb structure was manufactured in the same manner as in Example 1 except that a honeycomb formed body for the honeycomb fired body 120 was manufactured.

(Comparative Example 2)
When manufacturing the outer honeycomb fired body 120, the deformed cell 124a is a cell in which a circle having a diameter of 0.80 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction, and a circle having a diameter of 0.80 mm cannot be inserted. Change the shape of the mold for extrusion so that all the cells are filled with the wet mixture and become the outer peripheral wall of the honeycomb fired body, or the part is deleted and becomes a cross-sectional recess, A honeycomb structure was manufactured in the same manner as in Example 1 except that a honeycomb formed body for the outer honeycomb fired body 120 was manufactured.

(Evaluation of sealing failure)
Light leakage inspection was performed using 50 outer honeycomb fired bodies manufactured in Examples and Comparative Examples. The light leak test uses a light leak tester to shine light from the cell opening and confirm whether light leaks from the sealing side. If even one of the cells of the outer honeycomb fired body had light leakage, it was determined as defective and the sealing failure rate was calculated. The results are shown in Table 1 and FIG.

As is clear from the results in Table 1, in Example 2, the percentage of poorly sealed cells was 0%, whereas in Example 1, 2% was slightly poorly sealed. However, it was an acceptable defect rate.
On the other hand, in Comparative Examples 1 and 2, those with poor sealing greatly increased to 8% and 16%, respectively.

(Second embodiment)
Hereinafter, a second embodiment, which is another embodiment of the honeycomb structure of the present invention, will be described with reference to the drawings.
FIG. 5 is a cross-sectional view of the honeycomb structure according to the second embodiment of the present invention. Fig. 6 (a) is a cross-sectional view schematically showing the vicinity of the end face of the outer honeycomb fired body 220 constituting the honeycomb structure of the second embodiment of the present invention, and Fig. 6 (b) is a diagram of the present invention. FIG. 6 is a cross-sectional view schematically showing the vicinity of an end face of another outer honeycomb fired body 230 constituting the honeycomb structure of the second embodiment.

In the honeycomb structure 200 according to the present embodiment, as shown in FIG. 5, eight outer honeycomb fired bodies 220 and eight outer honeycomb fired bodies 230, and nine inner honeycombs arranged on the inside thereof. A plurality of honeycomb fired bodies 210 are bonded together through adhesive layers 201 </ b> A to 201 </ b> D to form a ceramic block 203, and a coat layer 202 is formed on the outer periphery of the ceramic block 203.
The shape of the cross section of the inner honeycomb fired body 210 is substantially square.
The cross section of the outer honeycomb fired body 220 has a shape surrounded by three line segments 220a, 220b, 220c and one substantially circular arc 220d, and is composed of two of these three line segments. Two angles (an angle formed by the line segment 220a and the line segment 220b and an angle formed by the line segment 220b and the line segment 220c) are both 90 °.
The cross section of the outer honeycomb fired body 230 is a substantially fan-shaped unit surrounded by three line segments 230a, 230b, 230c and one substantially arc 230d, and is composed of two of these three line segments. Two angles (an angle formed by the line segment 230b and the line segment 230c and an angle formed by the line segment 230a and the line segment 230b) are 90 ° and 135 °, respectively.
The honeycomb fired bodies 210, 220, and 230 are preferably made of a porous silicon carbide sintered body or porous silicon-containing silicon carbide.

As shown in FIG. 6 (a), the eight outer honeycomb fired bodies 220 have outer peripheral walls 228 constituting the outer periphery of the ceramic block 203, and the cells 221 and 224 (224a, 224a, 224b) includes outer peripheral cells 224a and 224b in contact with the outer peripheral wall 228 constituting the outer periphery of the ceramic block 203, and basic cells 221 positioned on the inner side of the outer peripheral cells 224a and 224b. The outer peripheral cells 224a and 224b of the outer honeycomb fired body 220 include a deformed cell 224a having a shape different from the basic cell 224b in addition to the basic cell 224b whose cross-sectional shape is perpendicular to the longitudinal direction. Is a cell in which a circle having a diameter of 0.90 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction. That is, in the case of a cell in which a circle having a diameter of 0.90 mm cannot be inserted, the cell is not formed, and the portion is completely filled with the same material as the cell wall to become the outer peripheral wall 228 of the honeycomb fired body, That portion is deleted to form a cross-sectional recess. Disposed inside the outer honeycomb fired body 220 is the inner honeycomb fired body 210. Reference numeral 222 denotes a sealing material.

Similarly to the outer honeycomb fired body 220, the eight outer honeycomb fired bodies 230 shown in FIG. 6B also have outer peripheral walls 238 that constitute the outer periphery of the ceramic block 203, and the cells of the outer honeycomb fired body 230. 231 and 234 (234a and 234b) are composed of outer peripheral cells 234a and 234b that are in contact with the outer peripheral wall 238 constituting the outer periphery of the ceramic block 203, and basic cells 231 located inside the outer peripheral cells 234a and 234b. The outer peripheral cells 234a and 234b of the outer honeycomb fired body 230 include a deformed cell 234a having a shape different from that of the basic cell 234b in addition to the basic cell 234b having a cross-sectional shape perpendicular to the longitudinal direction. Is a cell in which a circle having a diameter of 0.90 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction. That is, in the case of a cell in which a circle having a diameter of 0.90 mm cannot be inserted, the cell is not formed, and the portion is completely filled with the same material as the cell wall, and becomes the outer peripheral wall 238 of the honeycomb fired body, That portion is deleted to form a cross-sectional recess. Reference numeral 232 denotes a sealing material.

The cross-sectional shape perpendicular to the longitudinal direction of the outer peripheral walls 228 and 238 is an outer peripheral wall provided with a step formed by the convex portions 228a and 238a and the concave portions 228b and 238b, and the convex portions 228a and 238a and the concave portions 228b and 238b. The shape of the cross-section is configured by a curved line having an R-chamfered shape. The radius of curvature of the R chamfer is 0.3 to 2.5 mm.
Also in this honeycomb structure 200, either end of the cell is sealed with a sealing material, and the cell wall functions as a filter for collecting PM and the like.

Next, a method for manufacturing a honeycomb structure according to the present embodiment will be described.
The manufacturing method of the honeycomb structure in the present embodiment is the same as the manufacturing method of the honeycomb structure in the first embodiment of the present invention, except for the following points.
That is, the shape of the honeycomb formed body manufactured in the forming step (1) of the manufacturing method according to the first embodiment of the present invention is shown in FIG. 5 except that either end of the cell is not sealed. The bundling step (4) of the manufacturing method according to the first embodiment of the present invention is performed, and the inner honeycomb fired body 210 and the outer honeycomb fired bodies 220 and 230 shown in FIG. In the first embodiment of the present invention, except that the honeycomb fired bodies 210 and the outer honeycomb fired bodies 220 and 230 are bundled so that the honeycomb fired bodies are positioned at the positions shown in FIG. By using the same method as the method for manufacturing a honeycomb structure in the embodiment, the honeycomb structure according to the present embodiment of the present invention can be manufactured.

In the honeycomb structure according to the present embodiment, the same operational effects as those of the honeycomb structure according to the first embodiment of the present invention can be enjoyed.

Examples that more specifically disclose the second embodiment of the present invention will be described below. In addition, this invention is not limited only to these Examples.

(Example 3)
(1) Using the same method as the forming step (1) of Example 1, the shape was substantially the same as the inner honeycomb fired body 210 and the outer honeycomb fired bodies 220 and 230 shown in FIG. Thus, a raw honeycomb molded body without cell sealing was produced.

(2) Next, the raw honeycomb molded body is dried using a microwave dryer to obtain a dried honeycomb molded body, and then a predetermined cell is filled with a paste having the same composition as the wet mixture, and again It dried using the dryer.

(3) A degreasing step of degreasing the dried honeycomb formed body at 400 ° C. was performed, and further a firing step was performed at 2200 ° C. for 3 hours under an atmospheric pressure of argon atmosphere.
Accordingly, the porosity is 45%, the average pore diameter is 15 μm, the size is 34.5 mm × 34.5 mm × 200 mm, the number of cells (cell density) is 300 / inch ² , and the cell wall thickness is 0.00. Inner honeycomb fired body 210 made of a porous silicon carbide sintered body having a thickness of 25 mm (10 mil) and a cell width of 1.42 mm, porosity, average pore diameter, number of cells (cell density), cell wall thickness And the width of the cell is the same as that of the inner honeycomb fired body 210, and the cross section is surrounded by three line segments and one substantially circular arc, and two corners formed by two of the three line segments are both Outer honeycomb fired body 220 having a shape of 90 ° (line segment 220a = 45.6 mm, line segment 220b = 26.8 mm, line segment 220c = 41.8 mm), porosity, average pore diameter, number of cells ( Cell density), cell wall thickness and cell width The same as the honeycomb fired body 210, the cross section is surrounded by three line segments and one substantially circular arc, and two angles formed by two of the three line segments are 90 ° and 135 °, respectively. An outer honeycomb fired body 230 having a certain shape (line segment 230a = 24.9 mm, line segment 230b = 24.5 mm, line segment 230c = 41.8 mm) was manufactured. At this time, the deformed cells 224a and 234a are cells in which a circle having a diameter of 0.90 mm can be inserted into the inside of a cross-sectional shape perpendicular to the longitudinal direction, and a portion in which a circle having a diameter of 0.90 mm cannot be inserted is a cell. In addition, the cell portion is filled with the same material as the cell wall in advance to become the outer peripheral wall of the honeycomb fired body, or the portion is deleted to form a cross-sectional recess.

(4) Applying an adhesive paste to predetermined side surfaces of the inner honeycomb fired body 210 and the outer honeycomb fired bodies 220 and 230, and nine inner honeycomb fired bodies 210 via the adhesive paste, 5 pieces of the outer honeycomb fired bodies 220 and 8 pieces of the outer honeycomb fired bodies 230 are bonded so as to be arranged as shown in FIG. 5, and the adhesive paste is solidified at 180 ° C. for 20 minutes. As a result, a cylindrical ceramic block 203 having an adhesive layer thickness of 1 mm was produced.
Here, the adhesive paste similar to Example 1 was used as an adhesive paste.

(5) A coating material paste layer was formed on the outer periphery of the ceramic block 203 using the adhesive paste used in the step (4) as a coating material paste. Thereafter, this coating material paste layer was dried at 120 ° C. to manufacture a cylindrical honeycomb structure 200 having a diameter of 203.2 mm and a length of 200 mm, on which the coating layer 202 was formed on the outer periphery.

Example 4
When manufacturing the outer honeycomb fired bodies 220 and 230, the deformed cells 224a and 234a are formed into cells into which a circle having a diameter of 0.95 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction, and the circle having a diameter of 0.95 mm is formed. The shape of the mold for extrusion molding is such that all the cells that cannot be inserted are filled with the wet mixture to become the outer peripheral wall of the honeycomb fired body, or the portion is deleted to become a cross-sectional recess. A honeycomb structure was manufactured in the same manner as in Example 3, except that honeycomb formed bodies for the outer honeycomb fired bodies 220 and 230 were produced.

(Comparative Example 3)
When manufacturing the outer honeycomb fired bodies 220 and 230, the deformed cells 224a and 234a are formed into cells into which a circle having a diameter of 0.85 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction, and the circle having a diameter of 0.85 mm is formed. The shape of the mold for extrusion molding is such that all the cells that cannot be inserted are filled with the wet mixture to become the outer peripheral wall of the honeycomb fired body, or the portion is deleted to become a cross-sectional recess. A honeycomb structure was manufactured in the same manner as in Example 3, except that honeycomb formed bodies for the outer honeycomb fired bodies 220 and 230 were produced.

(Comparative Example 4)
When manufacturing the outer honeycomb fired bodies 220 and 230, the deformed cells 224a and 234a are formed into cells into which a circle having a diameter of 0.80 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction, and the circle having a diameter of 0.80 mm is formed. The shape of the mold for extrusion molding is such that all the cells that cannot be inserted are filled with the wet mixture to become the outer peripheral wall of the honeycomb fired body, or the portion is deleted to become a cross-sectional recess. A honeycomb structure was manufactured in the same manner as in Example 3, except that honeycomb formed bodies for the outer honeycomb fired bodies 220 and 230 were produced.

(Evaluation of sealing failure)
For the honeycomb structures according to Examples 3 to 4 and Comparative Examples 3 to 4, sealing failure occurred similarly to the case of the outer honeycomb fired bodies manufactured in Examples 1 and 2 and Comparative Examples 1 and 2. Whether or not the sealing failure rate was calculated. The results are shown in Table 2 and FIG.

As is clear from the results in Table 2, in Example 4, the percentage of poorly sealed cells was 0%, whereas in Example 3, 4% was slightly poorly sealed. However, it was an acceptable defect rate.
On the other hand, in Comparative Examples 3 and 4, those with poor sealing greatly increased to 12% and 18%, respectively.

FIG. 10 is a graph illustrating the diameter of an insertable circle and the sealing failure rate in Examples 1 to 4 and Comparative Examples 1 to 4.
As shown in FIG. 10, in the case of Example 1 to Example 4 in which the deformed cell is a cell in which a circle having a diameter of 0.90 mm or 0.95 mm can be inserted inside the cross-sectional shape perpendicular to the longitudinal direction, While it is considered that the defective rate of sealing is extremely small and there is no problem, a cell in which a circle having a diameter of 0.85 mm or 0.80 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction In the case of Comparative Examples 1 to 4, it cannot be said that the sealing failure rate is sufficiently low, and it can be seen that the production efficiency is lowered.

(Third embodiment)
FIG. 7A is a cross-sectional view schematically showing the vicinity of the end face of the outer honeycomb fired body constituting the honeycomb structure of the third embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view schematically showing the vicinity of an end face of an inner honeycomb fired body constituting the honeycomb structure of the third embodiment.
In the honeycomb structure according to the third embodiment of the present invention, the outer peripheral cell excluding the deformed cell and the basic cell are composed of a large capacity cell and a small capacity cell, and have a cross section perpendicular to the longitudinal direction of the large capacity cell. The area is made up of the honeycomb fired body 310 and the honeycomb fired body 320 having the same shape as the outer shape shown in FIGS. 2 and 3 except that the area of the cross section perpendicular to the longitudinal direction of the small capacity cell is larger. Further, the method of combining the honeycomb fired bodies 310 and 320 constituting the honeycomb structure is the same as that of the honeycomb structure shown in FIG.

That is, the shape of the cross section of the inner honeycomb fired body 310 is substantially square, and the cross section of the outer honeycomb fired body 320 has a shape surrounded by three line segments 320a, 320b, and 320c and one substantially arc 320d. The two corners formed by two of the three line segments (the angle formed by the line segment 320b and the line segment 320c and the angle formed by the line segment 320a and the line segment 320b) are 90 respectively. ° and 135 °.

As shown in FIGS. 7A and 7B, the outer honeycomb fired body 320 has an outer peripheral wall 328 constituting the outer periphery of the ceramic block, and the cells 321 (321a, 321b) of the outer honeycomb fired body 320 are provided. 324 (324a, 324b, 324c) are outer peripheral cells 324a, 324b, 324c that are in contact with the outer peripheral wall 328 constituting the outer periphery of the ceramic block, and basic cells 321a, 321b that are located inside the outer peripheral cells 324a, 324b, 324c, Consists of. The basic cell 321 includes a large-capacity cell 321a in which the area of the cross section perpendicular to the longitudinal direction is larger than the area of the cross-section perpendicular to the longitudinal direction of the small capacity cell 321b, and a small-capacity cell having a smaller cross-sectional area than the large capacity cell 321a. 321b.

The outer peripheral cells 324a, 324b, and 324c of the outer honeycomb fired body 320 have the same shape as the basic cells 324a and 324b in addition to the basic cells 324a and 324b that have the same cross-sectional shape as the basic cells 321a and 321b in the longitudinal direction. Different deformation cells 324c are included, and the deformation cell 324c is a cell in which a circle having a diameter of 0.90 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction. That is, in the case of a cell in which a circle having a diameter of 0.90 mm cannot be inserted, the cell is not formed, and the portion is completely filled with the same material as the cell wall to become the outer peripheral wall 328 of the honeycomb fired body, That portion is deleted to form a cross-sectional recess.
Disposed inside the outer honeycomb fired body 320 is an inner honeycomb fired body 310, which includes large capacity cells 311a and small capacity cells 311b. Reference numeral 322 denotes a sealing material.

The cross-sectional shape perpendicular to the longitudinal direction of the outer peripheral wall 328 is an outer peripheral wall provided with a step including a convex portion 328a and a concave portion 328b, and the cross-sectional shape of the convex portion 328a and the concave portion 328b is subjected to R chamfering. It is comprised by the curve of the shape made. The radius of curvature of the R chamfer is 0.3 to 2.5 mm.
Also in the honeycomb structure according to the third embodiment of the present invention, either end of the cell is sealed with a sealing material, and the cell wall functions as a filter for collecting PM and the like.
The honeycomb structure according to the third embodiment of the present invention has the same effects as those of the first embodiment of the present invention, and more PM than the honeycomb structure 100 having cells having the same cross-sectional area. Can be collected.

The honeycomb fired bodies 310 and 320 constituting the honeycomb structure are preferably porous bodies made of silicon carbide or silicon-containing silicon carbide.

(Fourth embodiment)
Fig.8 (a)-(c) is a figure which shows typically the honeycomb structure which concerns on 4th embodiment of this invention. Fig. 8 (a) is a cross-sectional view schematically showing a honeycomb structure 400 of the fourth embodiment of the present invention, and Fig. 8 (b) constitutes the honeycomb structure shown in Fig. 8 (a). FIG. 8C is a cross-sectional view schematically showing the vicinity of the end face of the outer honeycomb fired body 420, and FIG. 8C shows the vicinity of the end face of another outer honeycomb fired body 430 constituting the honeycomb structure shown in FIG. It is sectional drawing which shows this typically.

In the honeycomb structure 400 shown in FIGS. 8A to 8C, eight outer honeycomb fired bodies 420 having a shape as shown in FIG. 8B and 4 having a shape as shown in FIG. The outer honeycomb fired bodies 430 and the four inner honeycomb fired bodies 410 arranged on the inner side thereof are bound together via an adhesive layer 401 (401A to 401D) to form a ceramic block 403, A coat layer 402 is formed on the outer periphery of the ceramic block 403.
The shape of the cross section of the inner honeycomb fired body 410 is substantially square.
As shown in FIG. 8B, the cross section of the outer honeycomb fired body 420 has a shape surrounded by three line segments 420a, 420b, 420c and one substantially circular arc 420d. The angle between the line segment 420b and the angle between the line segment 420b and the line segment 420c were both 90 °. Further, as shown in FIG. 8C, the cross section of the outer honeycomb fired body 430 has a shape surrounded by two line segments 430a and 430b and one substantially arc 430c. The angle with the line segment 430b was 90 °.

As shown in FIG. 8B, the outer honeycomb fired body 420 has an outer peripheral wall 428 constituting the outer periphery of the ceramic block 403, and the cells 421, 424 (424a, 424b) of the outer honeycomb fired body 420 are formed. The outer peripheral cells 424a and 424b are in contact with the outer peripheral wall 428 constituting the outer periphery of the ceramic block 403, and the basic cells 421 are located inside the outer peripheral cells 424a and 424b. The outer peripheral cells 424a and 424b of the outer honeycomb fired body 420 include a modified cell 424a having a shape different from that of the basic cell 424b in addition to the basic cell 424b having the same cross-sectional shape as the basic cell 421 in the longitudinal direction. Is a cell in which a circle having a diameter of 0.90 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction. That is, in the case of a cell in which a circle having a diameter of 0.90 mm cannot be inserted, the cell is not formed, and the portion is completely filled with the same material as the cell wall to become the outer peripheral wall 428 of the honeycomb fired body, That portion is deleted to form a cross-sectional recess.

Further, as shown in FIG. 8C, the outer honeycomb fired body 430 has an outer peripheral wall 438 constituting the outer periphery of the ceramic block 403, and the cells 431, 434 (434a, 434b) of the outer honeycomb fired body 430 are formed. ) Includes outer peripheral cells 434a and 434b that are in contact with the outer peripheral wall 438 that forms the outer periphery of the ceramic block 403, and basic cells 431 that are located inside the outer peripheral cells 434a and 434b. The outer peripheral cells 434a and 434b of the outer honeycomb fired body 430 include a deformed cell 434a having a shape different from the basic cell 434b in addition to the basic cell 434b having the same cross-sectional shape as the basic cell 431 in the longitudinal direction. Is a cell in which a circle having a diameter of 0.90 mm can be inserted inside a cross-sectional shape perpendicular to the longitudinal direction. That is, in the case of a cell in which a circle having a diameter of 0.90 mm cannot be inserted, the cell is not formed, and the portion is completely filled with the same material as the cell wall to become the outer peripheral wall 438 of the honeycomb fired body, That portion is deleted to form a cross-sectional recess.

The cross-sectional shape perpendicular to the longitudinal direction of the outer peripheral walls 428 and 438 of the honeycomb fired body is an outer peripheral wall provided with a step formed by the convex portions 428a and 438a and the concave portions 428b and 438b, and the convex portions 428a and 438a and the concave portions are provided. The shape of the cross section of 428b, 438b is configured by a curved line having an R chamfered shape. The radius of curvature of the R chamfer is 0.3 to 2.5 mm.
Also in this honeycomb structure 400, either end of the cell is sealed with a sealing material, and the cell wall functions as a filter for collecting PM and the like.

The honeycomb fired bodies 410, 420, and 430 constituting the honeycomb structure 400 are preferably porous bodies made of silicon carbide or silicon-containing silicon carbide.

(Other embodiments)
The cross-sectional shape of the honeycomb structure according to the embodiment of the present invention is not limited to a substantially circular shape, and may be, for example, a substantially elliptical shape, a substantially oval shape, or a substantially racetrack shape.
In the embodiment of the present invention, the coat layer is formed on the outer peripheral surface of the ceramic block, but the coat layer may not be formed.

In the honeycomb structure according to the embodiment of the present invention, the number of the inner honeycomb fired bodies is not limited to a plurality, and may be one.
FIG. 9 is a cross-sectional view of a honeycomb structure according to another embodiment of the present invention.

The configuration of the honeycomb structure 700 shown in FIG. 9 is the same as that of the honeycomb structure 100 according to the first embodiment of the present invention, except that the number of inner honeycomb fired bodies is one.
That is, in the honeycomb structure 700 shown in FIG. 9, instead of the four inner honeycomb fired bodies 110 bound through the adhesive layer 101A of the honeycomb structure 100 shown in FIG. A honeycomb fired body 710 is provided.
Although the inner honeycomb fired body 710 has a larger cross-sectional area than the inner honeycomb fired body 110, its function is the same. The outer honeycomb fired body 720 is the same as the honeycomb fired body 120 constituting the honeycomb structure 100.

The cross-sectional shape perpendicular to the longitudinal direction of the outer peripheral wall of the honeycomb fired body is an outer peripheral wall provided with a step including a convex portion and a concave portion, and the cross-sectional shape of the convex portion and the concave portion is chamfered. It is desirable to have a shape.
The shape of the chamfer is not particularly limited, and it may be an R chamfer or a C chamfer, but it is preferably an R chamfered shape, and its curvature radius is 0.3 to 2.5 mm. It is desirable to be.

The thickness of the outer peripheral wall constituting the outer periphery of the ceramic block is not particularly limited, but is desirably thicker than the cell wall thickness of the honeycomb fired body (ceramic block) positioned inside, and is positioned inside. It is more desirable that the thickness is 1.3 to 3.0 times the cell wall thickness of the honeycomb fired body (ceramic block).

In the honeycomb structure according to the embodiment of the present invention, the cross-sectional area perpendicular to the longitudinal direction of the inner honeycomb fired body is desirably 900 to 2500 mm ² .
This is because when the cross-sectional area of the inner honeycomb fired body is within the above range, cracks due to expansion or contraction of the honeycomb fired body are less likely to occur in the honeycomb fired body when the honeycomb structure is subjected to regeneration treatment. .

In the honeycomb structure according to the embodiment of the present invention, the outer peripheral cell and the basic cell excluding the deformed cell may be composed of a large capacity cell and a small capacity cell as shown in FIG. In this case, the cross-sectional shapes of the large-capacity cell and the small-capacity cell are not particularly limited. However, as shown in FIG. 7, the cross-sectional shape of the large-capacity cell is a substantially octagonal shape. The cross-sectional shape may be a substantially square shape, the cross-sectional shape perpendicular to the longitudinal direction of the large-capacity cell may be a substantially square shape, and the cross-sectional shape perpendicular to the longitudinal direction of the small-capacity cell may be a substantially square shape. Moreover, the cross-sectional shape of each side of the cell may be configured by a curve.
In the honeycomb structure according to the embodiment of the present invention, the area ratio of the cross section perpendicular to the longitudinal direction of the large capacity cell to the cross section perpendicular to the longitudinal direction of the small capacity cell (large capacity cell sectional area / small capacity cell sectional area) is 1.01 to 9.00 is preferable.

In the honeycomb structure according to the embodiment of the present invention, the ends of the cells may not be sealed. Such a honeycomb structure can be used as a catalyst carrier.
The ceramic block according to the embodiment of the present invention may be composed of a cake-shaped honeycomb fired body. The number of cake-shaped honeycomb fired bodies may be one or plural, and the number is not particularly limited.
The cake shape refers to one columnar body that is cut into a plurality of pieces so that the column passes through the central axis. When a plurality of cake-shaped honeycomb fired bodies are combined, the shape becomes a columnar shape.
Moreover, the ceramic block may be comprised from one honeycomb fired body.
When the ceramic block is composed of one honeycomb fired body, the honeycomb fired body is preferably made of cordierite or aluminum titanate. It is considered that the same effect can be obtained even when it is composed of one honeycomb fired body.

Examples of the inorganic binder contained in the adhesive paste and the coating material paste include silica sol and alumina sol. These may be used alone or in combination of two or more. Among inorganic binders, silica sol is desirable.

Examples of the inorganic particles contained in the adhesive paste and the coating material paste include inorganic particles made of carbide, nitride, etc., specifically, inorganic particles made of silicon carbide, silicon nitride, boron nitride. Etc. These may be used alone or in combination of two or more. Among the inorganic particles, inorganic particles made of silicon carbide having excellent thermal conductivity are desirable.

Examples of the inorganic fibers and / or whiskers contained in the adhesive paste and the coating material paste include inorganic fibers and / or whiskers made of silica-alumina, mullite, alumina, silica and the like. These may be used alone or in combination of two or more. Among inorganic fibers, alumina fibers are desirable.

The honeycomb fired body preferably has an average pore diameter of 5 to 30 μm. When a honeycomb structure made of a honeycomb fired body is used as a honeycomb filter, if the average pore diameter of the honeycomb fired body is less than 5 μm, the particulates may be easily clogged, while the average pore diameter is 30 μm. This is because the particulates may pass through the pores, and the particulates cannot be collected and cannot function as a filter.

In addition, the said porosity and average pore diameter can be measured by the mercury intrusion method which is a conventionally well-known method.

Although the cell density in the cross section of the honeycomb fired body is not particularly limited, the desirable lower limit is 31.0 / cm ² (200 / in ² ), and the desirable upper limit is 93 / cm ² (600 / in ² ). The more desirable lower limit is 38.8 / cm ² (250 / in ² ), and the more desirable upper limit is 77.5 / cm ² (500 / in ² ).
Further, the thickness of the cell wall of the honeycomb fired body is not particularly limited, but is desirably 0.1 to 0.4 mm.

The main component of the constituent material of the honeycomb fired body is not limited to silicon carbide, and as other ceramic raw materials, for example, nitride ceramics such as aluminum nitride, silicon nitride, boron nitride, titanium nitride, zirconium carbide, Examples thereof include carbide ceramics such as titanium carbide, tantalum carbide, and tungsten carbide, and oxide ceramics such as cordierite and aluminum titanate.
Among these, in the case of a honeycomb structure including a plurality of honeycomb fired bodies, the main component of the honeycomb fired body is preferably a non-oxide ceramic, and particularly preferably silicon carbide or silicon-containing silicon carbide. It is because it is excellent in heat resistance, mechanical strength, thermal conductivity and the like.

It does not specifically limit as an organic binder mixed with the said wet mixture, For example, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyethyleneglycol etc. are mentioned. Of these, methylcellulose is desirable. In general, the blending amount of the organic binder is desirably 1 to 10 parts by weight with respect to 100 parts by weight of the ceramic powder.
The plasticizer mixed with the wet mixture is not particularly limited, and examples thereof include glycerin.
The lubricant mixed in the wet mixture is not particularly limited, and examples thereof include polyoxyalkylene compounds such as polyoxyethylene alkyl ether and polyoxypropylene alkyl ether. Specific examples include polyoxyethylene monobutyl ether and polyoxypropylene monobutyl ether.
In some cases, the plasticizer and the lubricant may not be contained in the wet mixture.

In preparing the wet mixture, a dispersion medium liquid may be used. Examples of the dispersion medium liquid include water, an organic solvent such as benzene, and an alcohol such as methanol.
Furthermore, a molding aid may be added to the wet mixture.
The molding aid is not particularly limited, and examples thereof include ethylene glycol, dextrin, fatty acid, fatty acid soap, polyalcohol and the like.

Furthermore, a pore-forming agent such as balloons that are fine hollow spheres containing oxide-based ceramics, spherical acrylic particles, and graphite may be added to the wet mixture as necessary.
The balloon is not particularly limited, and examples thereof include an alumina balloon, a glass micro balloon, a shirasu balloon, a fly ash balloon (FA balloon), and a mullite balloon. Of these, alumina balloons are desirable.

The honeycomb structure may support a catalyst for purifying exhaust gas. As the catalyst to be supported, for example, a noble metal such as platinum, palladium, rhodium or the like is desirable, and among these, platinum is more desirable. Further, as other catalysts, for example, alkali metals such as potassium and sodium, and alkaline earth metals such as barium can be used. These catalysts may be used alone or in combination of two or more.

The bundling step in the method for manufacturing a honeycomb structure according to the embodiment of the present invention is not limited to the method of applying the adhesive paste to the side surface of each honeycomb fired body, for example, a ceramic block to be produced (or an aggregate of honeycomb fired bodies) Alternatively, the honeycomb fired bodies may be temporarily fixed in a mold having substantially the same shape as the above shape, and an adhesive paste may be injected between the honeycomb fired bodies.

100, 200, 400, 700 Honeycomb structure 101, 101A-101D, 201A-201D, 401A-401D, 701B-701D Adhesive layer 102, 202, 402, 702 Coat layer 103, 203, 403, 703 Ceramic block 110, 210, 310, 410, 710 Inner honeycomb fired body 120, 220, 230, 310, 320, 420, 430, 720 Outer honeycomb fired body 128, 228, 238, 328, 428, 438 Outer peripheral wall 111, 121, 124b 221, 224b, 231, 234b, 311a, 311b, 321a, 321b, 324a, 324b, 421, 424b, 431, 434b Cell 124a, 224a, 234a, 324c, 424a, 434a Modified cell 112, 122, 222 232,312,322,422,432 sealant 113,123,223,233,313,323,423,433 cell wall

Claims (17)

A honeycomb structure comprising a ceramic block composed of a honeycomb fired body in which a large number of cells are arranged in parallel in the longitudinal direction across a cell wall, and an outer peripheral wall is formed on the outer periphery,
The cell consists of an outer peripheral cell in contact with the outer peripheral wall of the honeycomb fired body constituting the outer periphery of the ceramic block, and a basic cell located on the inner side of the outer peripheral cell,
The outer circumferential cell includes a deformed cell having a cross-sectional shape perpendicular to the longitudinal direction different from the basic cell,
The honeycomb structure according to claim 1, wherein the deformable cell is a cell in which a circle having a diameter of 0.90 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction. The honeycomb structure according to claim 1, wherein the deformable cell is a cell in which a circle having a diameter of 0.95 mm can be inserted into a cross-sectional shape perpendicular to the longitudinal direction. The outer peripheral wall constituting the outer periphery of the ceramic block has a cross-sectional shape perpendicular to the longitudinal direction of the honeycomb fired body, and the inside of the deformed small cell in which a circle having a diameter of 0.90 mm cannot be inserted is the same as the cell wall The honeycomb structure according to claim 1 or 2, comprising an outer peripheral wall completely filled with a material. The honeycomb structure according to any one of claims 1 to 3, wherein the ceramic block is formed by binding a plurality of honeycomb fired bodies through an adhesive layer. The ceramic block is a combination of the honeycomb fired bodies having different shapes, an outer honeycomb fired body having an outer peripheral wall constituting the outer periphery of the ceramic block, and an inner honeycomb positioned inside the outer honeycomb fired body The honeycomb structure according to claim 4, comprising a fired body. The cross-sectional shape perpendicular to the longitudinal direction of the outer peripheral wall of the honeycomb fired body constituting the outer periphery of the ceramic block is an outer peripheral wall provided with a step composed of a convex part and a concave part,
The honeycomb structure according to any one of claims 1 to 5, wherein the convex portion and / or the concave portion is configured by a curve having a shape in which the convex portion and / or the concave portion is chamfered. The convex portion and / or the concave portion has a shape in which an R chamfer is applied to the convex portion and / or the concave portion, and a radius of curvature of the R chamfer is 0.3 to 2.5 mm. 7. The honeycomb structure according to 6. The shape of a cross section perpendicular to the longitudinal direction of the outer peripheral cell excluding the deformed cell and the shape of a cross section perpendicular to the longitudinal direction of the basic cell are substantially quadrangular. The honeycomb structure described. The outer peripheral cell excluding the deformed cell and the basic cell are composed of a large capacity cell and a small capacity cell,
The honeycomb structure according to any one of claims 1 to 8, wherein an area of a cross section perpendicular to the longitudinal direction of the large capacity cell is larger than an area of a cross section perpendicular to the longitudinal direction of the small capacity cell. The honeycomb structure according to claim 9, wherein a shape of a cross section perpendicular to the longitudinal direction of the large-capacity cell is a substantially square shape, and a shape of a cross section perpendicular to the longitudinal direction of the small-capacity cell is a substantially square shape. The honeycomb structure according to claim 9, wherein a shape of a cross section perpendicular to the longitudinal direction of the large capacity cell is substantially octagonal, and a shape of a cross section perpendicular to the longitudinal direction of the small capacity cell is substantially square. The honeycomb structure according to claim 9, wherein in the cross section perpendicular to the longitudinal direction of the large capacity cell and the small capacity cell, the shape of the cross section perpendicular to the longitudinal direction of each side of the cell is configured by a curve. The honeycomb structure according to any one of claims 1 to 12, wherein the thickness of the outer peripheral wall of the honeycomb fired body constituting the outer periphery of the ceramic block is thicker than the thickness of the cell wall located inside the honeycomb fired body. The honeycomb according to claim 13, wherein the thickness of the outer peripheral wall of the honeycomb fired body constituting the outer periphery of the ceramic block is 1.3 to 3.0 times the thickness of the cell wall of the honeycomb fired body located inside. Structure. The cross section of the outer honeycomb fired body has a substantially sector shape in which the shape of the cross section perpendicular to the longitudinal direction is a shape surrounded by three straight lines and an outer peripheral wall constituting a part of the outer periphery of the ceramic block, The honeycomb structure according to any one of claims 5 to 14, wherein a cross section of the inner honeycomb fired body is a substantially square unit in which a shape of a cross section perpendicular to the longitudinal direction is a substantially square shape. The honeycomb structure according to any one of claims 1 to 15, wherein one end of each of the cells is alternately sealed. The honeycomb structure according to any one of claims 1 to 16, wherein a coat layer is formed on an outer peripheral surface of the ceramic block.

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