JP5450010B2 - Honeycomb structure - Google Patents

Description

  The present invention relates to a honeycomb structure, and more specifically, prevents exhaust gas from leaking between the honeycomb structure and the can body when the honeycomb structure is installed in a pipe for storing exhaust gas in a can body. The present invention relates to a honeycomb structure.

  Ceramic honeycomb structure with excellent heat resistance and corrosion resistance is used as a carrier or filter for catalyst devices used for environmental measures and recovery of specific substances in various fields such as chemistry, electric power, steel, etc. Has been. In particular, recently, a honeycomb structure has a plugged honeycomb structure by alternately plugging the cell openings on both end faces, and particulate matter (PM: particulate matter) discharged from a diesel engine or the like. It is actively used as a diesel particulate filter (DPF) that collects water. As a material for the honeycomb structure used in a high temperature and corrosive gas atmosphere, silicon carbide (SiC), cordierite, aluminum titanate (AT), etc. excellent in heat resistance and chemical stability are suitable. It is used for.

  Since silicon carbide has a relatively high coefficient of thermal expansion, a honeycomb structure formed using silicon carbide as an aggregate may have a defect due to thermal shock during use when a large structure is formed. In addition, defects may occur due to thermal shock when the collected particulate matter is removed by combustion. Therefore, for a honeycomb structure formed using silicon carbide as an aggregate, when manufacturing a structure having a predetermined size or more, usually, a plurality of small plugged honeycomb structure segments (honeycomb segments) are prepared, These segments are joined to produce one large joined body, and the outer periphery thereof is roughly processed and ground to form a plugged honeycomb structure having a desired shape such as a cylindrical shape (for example, see Patent Documents 1 and 2). ). And joining of a segment is performed using a joining material, a joining material is apply | coated to the side surface (outer peripheral surface) of a predetermined segment, and the several segment is joined by the side surfaces. Thereby, a honeycomb structure in which a plurality of segments are bonded via the bonded portion is obtained.

JP 2003-291054 A JP 2001-96117 A

  As in the prior art, when joining a plurality of segments to produce one large joined body, the outer periphery thereof is roughly processed and ground to produce a plugged honeycomb structure of a desired shape such as a cylindrical shape, There was a problem that raw material loss was caused by roughing and grinding. Further, since an extra step such as grinding is required, there is a problem that the production efficiency is lowered.

  In addition, when the cylindrical plugged honeycomb structure having a circular or oval bottom surface is mounted in a square space, there is a problem that the corner portion of the space becomes empty and the mounting space is wasted. . On the other hand, in the case of a plugged honeycomb structure having a rectangular bottom, the plugged honeycomb structure is also disposed at the corner of the space when mounted in a square space. Never waste. Such a cylindrical plugged honeycomb structure with a rectangular bottom surface is effective when mounted in a narrow space such as an automobile, and the narrow space is effective when the space shape is close to a square. Can be used.

  However, the cylindrical plugged honeycomb structure having a rectangular bottom surface is plugged when the cushioning material or the like is placed in a can body or the like in a state of being arranged on the side surface of the plugged honeycomb structure. There is a problem in that a gap is formed between the corner of the honeycomb structure and the cushion material or the like. When such a gap is formed, there arises a problem that the exhaust gas is discharged through the gap without being processed by the plugged honeycomb structure.

  The present invention has been made in view of the above-described problems, and exhaust gas leaks from between the honeycomb structure and the can when it is installed in a pipe for storing in a can and discharging exhaust gas. An object of the present invention is to provide a honeycomb structure capable of preventing the above.

  In order to solve the above-described problems, the present invention provides the following honeycomb structure.

[1] A porous partition wall that partitions and forms a plurality of cells serving as fluid flow paths, and an outer peripheral wall located at the outermost periphery, an opening of a predetermined cell on an end surface on the fluid inlet side, A plurality of rectangular pillar-shaped honeycomb segments having plugged portions at the openings of the remaining cells on the end surface on the outlet side are provided, and the plurality of honeycomb segments have a cell density of 15.5 to 62.0 cells / cm. ² and in a cross section perpendicular to the cell extending direction, the outer peripheral wall is a quadrangle having arcuate corners, and the plurality of honeycomb segments are adjacent to each other such that their side surfaces face each other. In addition, in the cross section perpendicular to the cell extending direction, the opposing side surfaces are bonded to each other by a bonding portion, and the overall shape is a quadrangle, and the honeycomb cells are arranged at the four corners of the overall shape. Among the corners of the mentament, the corners forming the vertices in the overall shape are formed in an arc shape having a radius not less than the length of two cell pitches and not more than the length of one side of the honeycomb segment, and the cell extending direction In the cross section orthogonal to the above, all the corners of the honeycomb segment excluding the honeycomb segments arranged at the four corners are formed in a circular arc shape having a radius not less than the length of 1 cell pitch and less than the length of 3 cell pitch. In the cross section perpendicular to the extending direction, the radius of the arc-shaped corners forming the apexes in the overall shape is the radius of all the arc-shaped corners of the honeycomb segment excluding the honeycomb segments arranged at the four corners. A honeycomb structure larger than the radius .

[2] The honeycomb structure according to [1], wherein among the plurality of honeycomb segments, the honeycomb segments excluding the honeycomb segments arranged at the four corners have the same shape.

[3] The honeycomb structure according to [1], wherein the plurality of honeycomb segments have the same shape.

  According to the honeycomb structure of the present invention, in the cross section orthogonal to the cell extending direction, the overall shape is a quadrangle, and the apex in the overall shape is formed among the corners of the honeycomb segments arranged at the four corners of the overall shape. The honeycomb segments are formed in an arc shape having a radius of “a length of 2 cell pitch or more and a length of one side of the honeycomb segment” and further arranged at four corners in a cross section orthogonal to the cell extending direction. All the corners of the honeycomb segment except for are formed in a circular arc shape having a radius of 1 cell pitch or more and less than 3 cell pitch lengths, and in the cross section perpendicular to the cell extending direction, the apex in the overall shape The radius of the arcuate corners to be formed is greater than or equal to the radius of all arcuate corners of the honeycomb segment excluding the honeycomb segments arranged at the four corners. Therefore, when it is housed in a can body and attached to an exhaust gas pipe, exhaust gas can be prevented from leaking between the honeycomb structure and the can body, and stress is applied to the honeycomb structure. Therefore, the corner portions of the adjacent honeycomb segments can be prevented from coming into contact with each other. Moreover, the unevenness | corrugation of the outer periphery of a honeycomb structure can be made small.

1 is a perspective view schematically showing an embodiment of a honeycomb structure of the present invention. 1 is a schematic diagram showing a cross section orthogonal to a cell extending direction of an embodiment of a honeycomb structure of the present invention. [Fig. 3] Fig. 3 is a schematic view showing a part of a cross section perpendicular to a cell extending direction of a honeycomb segment constituting one embodiment of a honeycomb structure of the present invention. Fig. 3 is a plan view showing a part of one end face of a honeycomb segment constituting one embodiment of a honeycomb structure of the present invention. [Fig. 3] Fig. 3 is a schematic view showing a part of a cross section parallel to the cell extending direction of a honeycomb segment constituting one embodiment of the honeycomb structure of the present invention. It is a schematic diagram which shows the cross section orthogonal to the cell extending direction of other embodiment of the honeycomb structure of this invention. FIG. 6 is a schematic view showing a cross section perpendicular to the cell extending direction of still another embodiment of the honeycomb structure of the present invention. 1 is a schematic view showing a state in which one embodiment of a honeycomb structure of the present invention is housed in a can body and showing a cross section orthogonal to a cell extending direction. FIG.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and those skilled in the art do not depart from the spirit of the present invention. It should be understood that design changes, improvements, and the like can be made as appropriate based on ordinary knowledge.

(1) Honeycomb structure:
As shown in FIGS. 1 to 4, one embodiment of the honeycomb structure of the present invention includes a porous partition wall 2 that partitions and forms a plurality of cells 1 that serve as fluid flow paths, and an outer peripheral wall located at the outermost periphery. A rectangular column-shaped honeycomb having an opening portion of a predetermined cell 1 on the end surface 11 on the fluid inlet side and a plugging portion 6 on an opening portion of the remaining cell 1 on the end surface 12 on the fluid outlet side. A plurality of segments 4 are provided, and a plurality of honeycomb segments 4 are arranged adjacent to each other such that the side surfaces 5 face each other, and the side surfaces 5 facing each other are joined by the joint portion 13 to extend the cell. In the cross section orthogonal to the direction, the overall shape is a quadrangle, and the corner portions 7 (each honeycomb segment is a honeycomb segment arranged at the four corners of the overall shape (four “corner positions 22 of the honeycomb structure 100”)). One Among the corner portions 7R and the three corner portions 7r), the corner portion 7 (7R) forming the apex 21 in the overall shape is not less than the length of the two-cell pitch P and not more than the length L of one side of the honeycomb segment 4 All corners of the honeycomb segment 4 except for the honeycomb segments 4 arranged at the four corners (four corner positions 22 of the honeycomb structure 100) in a cross section that is formed in an arc shape with a radius of and perpendicular to the cell extending direction. The portion 7 (7r) is formed in an arc shape having a radius not less than the length of 1 cell pitch P and less than the length of 3 cell pitch P, and forms a vertex in the overall shape in a cross section perpendicular to the cell extending direction. The radius of the “arc-shaped corner 7 (7R)” is longer than the radius of all the “arc-shaped corner 7 (7r)” of the honeycomb segments excluding the honeycomb segments arranged at the four corners.
It is a thing.

  FIG. 1 is a perspective view schematically showing one embodiment of a honeycomb structure of the present invention. Fig. 2 is a schematic diagram showing a cross section perpendicular to the cell extending direction of one embodiment of the honeycomb structure of the present invention. FIG. 3 is a schematic diagram showing a part of a cross section perpendicular to the cell extending direction of the honeycomb segment constituting one embodiment of the honeycomb structure of the present invention. FIG. 4 is a plan view showing a part of one end face of the honeycomb segment constituting one embodiment of the honeycomb structure of the present invention. In FIG. 1, partition walls, cells, and plugging portions are omitted.

  As described above, the honeycomb structure 100 of the present embodiment has a square overall shape in a cross section perpendicular to the cell extending direction, and the overall shape of the corners of the honeycomb segments arranged at the four corners of the overall shape. The corners that form the apex are formed in an arc shape with a radius of “more than the length of two cell pitches and less than the length of one side of the honeycomb segment”, so they are housed in cans and attached to exhaust gas pipes. When this is done, it is possible to prevent the exhaust gas from leaking between the honeycomb structure 100 and the can body. That is, the four apexes (corners) in the cross section perpendicular to the cell extending direction of the honeycomb structure 100 having a rectangular bottom surface (hereinafter sometimes referred to as “quadrangular columnar shape”) have a predetermined size. Since it is formed in an arc shape, when the honeycomb structure 100 is used in a can body or the like in a state where a cushion material or the like is arranged on the side surface, four apexes (corners) of the honeycomb structure 100, It is possible to prevent a gap from being formed between the cushion material and the like, and to prevent the exhaust gas from leaking. Further, in the cross section perpendicular to the cell extending direction, all the corners of the honeycomb segment excluding the honeycomb segments arranged at the four corners are formed in an arc shape having a radius of 1 cell pitch or more and less than 3 cell pitch length. In addition, in the cross section orthogonal to the cell extending direction, the radius of the arcuate corners forming the apexes of the overall shape is the same for all arcuate corners of the honeycomb segment except for the honeycomb segments arranged at the four corners. Since the length is longer than the radius, it is possible to prevent the corners of the adjacent honeycomb segments from contacting each other when the honeycomb structure is slightly deformed due to stress, and the honeycomb structure Unevenness on the outer periphery of the body can be reduced.

  In addition, since the honeycomb structure 100 of the present embodiment has a quadrangular prism shape, the area of a cross section orthogonal to the flowing direction of the exhaust gas (the cell extending direction) in a narrow space (particularly a square space) of an automobile or the like is maximized. Can be limited. As a result, the maximum soot (particulate matter) deposition capacity can be secured in a space of a certain volume, and when the exhaust gas passes through the initial stage of soot deposition and after a certain amount of soot is deposited, respectively. It is possible to reduce the pressure loss. For example, the honeycomb structure 100 of the present embodiment in which one side of the bottom surface is 143.8 mm (four vertices have an arc shape with a radius of “one side of the honeycomb segment”), and a circle having a bottom surface diameter of 143.8 mm When compared with the columnar honeycomb structure, the soot deposition capacity is 1.1 times that of the columnar honeycomb structure of the honeycomb structure 100 of the present embodiment, and the pressure loss is the honeycomb structure 100 of the present embodiment. Is reduced by 10% with respect to the cylindrical honeycomb structure.

  Here, “the corner 7 (7R) is formed in an arc shape having a radius of not less than the length of the two-cell pitch P and not more than the length L of one side of the honeycomb segment 4” means that the corner 7 (honeycomb structure). The corner 7R of the honeycomb segment located at the apex of the body is formed in an arc shape as shown in FIGS. 1 and 2, and the radius of the arc is “the length of two or more cell pitches P, the honeycomb segment. 4 or less of one side length L ”. In addition, in the cross section orthogonal to the cell extending direction, all the corners 7 (7r) of the honeycomb segment excluding the honeycomb segments arranged at the four corners have a radius that is greater than or equal to the length of 1 cell pitch and less than the length of 3 cell pitch. Is formed in an arc shape as shown in FIGS. 1 and 2. Corner portions 7 (corner portion corners 7r of the honeycomb segments that do not constitute the four corners (corner positions) of the honeycomb structure) are formed in an arc shape as shown in FIGS. This means that the radius of the arc is “more than the length of one cell pitch P and less than the length of three cell pitches P”. Further, as shown in FIG. 3, the “cell pitch” is a length obtained by adding a value obtained by doubling “1/2 of the partition wall thickness T” to the width W of one cell (that is, cell pitch = W + T). Further, “the length of one side of the honeycomb segment 4” is a normal quadrangle in which the corners of the honeycomb segment 4 are not arc-shaped in the cross section orthogonal to the cell extending direction, and the honeycomb segment 4 is formed only from a straight line. It is the length of one side when it is assumed.

  In the honeycomb structure 100 of the present embodiment, the cell shape is square and the honeycomb segment 4 is square in the cross section perpendicular to the cell extending direction. When the shape of the cell is a rectangle, the cell width W is the average length in the vertical and horizontal directions. When the honeycomb segment has a rectangular shape, the length L of one side of the honeycomb segment 4 is the average length in the vertical and horizontal directions. When the cell shape is hexagonal or octagonal, the cell width W is the shortest length among the distances between the two opposing sides. For example, in the case of a hexagon, there are three pairs of two opposite sides, but the shortest distance among the two pairs of two opposite sides.

  In the honeycomb structure 100 of the present embodiment, a plurality of “quadrangular columnar honeycomb segments 4 having plugged portions” are arranged adjacent to each other so that the side surfaces 5 face each other, and the side surfaces 5 that face each other. This is a structure in which the members are joined together by a joint 13. And in the cross section orthogonal to the cell extending direction, the overall shape is a quadrangle, and a square or a rectangle is preferable. In addition, the overall shape of the honeycomb structure 100 of the present embodiment in the cross section orthogonal to the cell extending direction can be suitably made a quadrilateral having a preferable shape depending on the size and shape of the mounting space of an automobile or the like.

  The honeycomb structure 100 of the present embodiment has a quadrangular overall shape in a cross section perpendicular to the cell extending direction, and is arranged at “four corners of the entire shape (four corner positions 22 of the honeycomb structure 100”). Among the corner portions 7 of the “honeycomb segment” (each honeycomb segment has one corner portion 7R and three corner portions 7r), the corner portion 7R (hereinafter referred to as “the vertex position”) forming the vertex 21 in the overall shape. Is formed in an arc shape having a radius not less than “the length of two cell pitches P” and not more than “the length L of one side of the honeycomb segment 4”. It is preferable that the corner portion 7 </ b> R positioned in the arc is formed in an arc shape having a radius not less than “the length of the two-cell pitch P” and not more than “½ the length L of one side of the honeycomb segment 4”. Cell pitch P Or more in length, it is more preferably formed in a 5 cell pitch arcuate radius of less than the length of the P. When the “corner portion 7R located at the apex” is formed in an arc shape with a radius smaller than “the length of the two-cell pitch P”, the honeycomb structure is arranged on the side surface with a cushioning material etc. When storing and using, a gap is formed between the “corner portion 7R positioned at the apex” and the cushion material or the like, which is not preferable. In particular, it is not preferable because a gap is formed due to vibration during use and becomes larger. Further, when the “corner portion 7R located at the apex” is formed in an arc shape having a radius exceeding the “length L of one side of the honeycomb segment 4”, the area of the cross section perpendicular to the direction in which the exhaust gas passes is small. Therefore, when processing exhaust gas, the pressure loss tends to increase, which is not preferable. Further, in this case, the joint between the arc-shaped portion and the linear portion does not become a smooth connection, so that a gap is easily formed between the cushion material and the like, which is not preferable.

  In addition, the honeycomb structure 100 of the present embodiment has “cross-sections perpendicular to the cell extending direction” of “four honeycomb segments arranged at four corners 22 of the honeycomb structure 100” in the overall shape. Among the corner portions 7 (each honeycomb segment has one corner portion 7R and three corner portions 7r), the corner portion 7 (corner portion 7r) excluding “the corner portion 7R located at the apex” is 1 cell pitch. All the arc shapes of the honeycomb segments excluding the honeycomb segments arranged at the four corners are formed in an arc shape having a radius of not less than the length of 3 cells and less than the length of 3 cell pitches. It is preferable that the length is equal to or longer than the radius of the corner 7r. As a result, when the honeycomb structure is slightly deformed due to stress, it is possible to prevent the corner portions of the adjacent honeycomb segments from coming into contact with each other. Can be reduced.

  In the honeycomb structure 100 of the present embodiment, the honeycomb segment 4 excluding “the four honeycomb segments 4 arranged at the corners 22 of the honeycomb structure 100” in the cross section orthogonal to the cell extending direction. All of the corners 7r (hereinafter sometimes referred to as “honeycomb segments other than the four corners”) have an arc shape having a radius that is greater than or equal to “the length of one cell pitch P” and less than “the length of three cell pitch P”. It is formed. In this way, all the corners 7r of the “honeycomb segments other than the four corners” are formed in an arc shape having a radius that is greater than or equal to “the length of one cell pitch P” and less than the “length of three cell pitch P”. Further, it is possible to prevent the corner portions of the adjacent honeycomb segments from coming into contact with each other. When all the corners 7r of the “honeycomb segments other than the four corners” are formed in an arc shape having a radius smaller than the “length of one cell pitch P”, the honeycomb structure is slightly deformed due to stress. Since the corner portions 7r of the honeycomb segments arranged adjacent to each other come into contact with each other and the corner portions 7r are broken, it is not preferable. Further, if all the corners 7r of the “honeycomb segments other than the four corners” are formed in an arc shape having a large radius equal to or greater than “the length of the three-cell pitch P”, the cell extending direction (exhaust gas) In the cross section orthogonal to the direction in which the gas flows, the ratio of the joint portion increases, and the area (cross-sectional area) where the exhaust gas can be processed becomes small. Thus, when the area (cross-sectional area and partition wall area) for treating the exhaust gas becomes small, the pressure loss when treating the exhaust gas becomes large, and the amount of exhaust gas treated becomes small. Here, “less than 3 cell pitch P length” means less than 3 times the cell pitch P. Note that “the length of one cell pitch P” is one time as long as the cell pitch P. Moreover, it is preferable that the radius of the arc-shaped corner portion 7R forming the apex is longer than the radius of all the arc-shaped corner portions 7r of the honeycomb segment excluding the honeycomb segments arranged at the four corners. Thereby, the unevenness | corrugation of the outer periphery of a honeycomb structure can be made small.

  In the honeycomb structure 100 of the present embodiment, among the plurality of honeycomb segments 4, it is preferable that the honeycomb segments 4 (honeycomb segments other than the four corners) excluding the honeycomb segments 4 arranged at the four corners have the same shape. Thereby, it is possible to prevent the exhaust gas from leaking at the outer periphery of the honeycomb structure 100 at portions other than the “four apex portions” of the honeycomb structure 100. Moreover, the unevenness | corrugation of an outer periphery can be reduced.

  In the honeycomb structure 100 of the present embodiment, all of the plurality of honeycomb segments 4 have the same shape. Therefore, variation in the shape (size) of each segment is small, and in the overall shape of the honeycomb structure 100, unevenness on the outer periphery (such as unevenness at the joint between segments) is reduced. Thereby, it is possible to prevent the exhaust gas from leaking at the outer periphery of the honeycomb structure 100 at portions other than the “four apex portions” of the honeycomb structure 100. Moreover, by making the shape of all the honeycomb segments 4 the same, all the segments can be formed with the same raw material at a time. Therefore, the characteristics (porosity, strength, partition wall thickness, cell pitch, etc.) between the honeycomb segments can be made uniform, and as a result, the dimensional variation can be reduced. Further, since the manufacturing lots of the respective honeycomb segments are the same, it is easy to trace the manufacturing history of the honeycomb segments even after the honeycomb structure is manufactured.

  Thus, when the plurality of honeycomb segments 4 have the same shape, the honeycomb segment 4 has four corners of “the length of the two-cell pitch P” or more in a cross section orthogonal to the cell extending direction. It is formed in an arc shape with a radius less than “the length of the three-cell pitch P”.

  As the material of the honeycomb segment constituting the honeycomb structure of the present embodiment, ceramic is preferable, and since it is excellent in strength and heat resistance, silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, spinel, More preferably, it is at least one selected from the group consisting of silicon carbide-cordierite composite material, lithium aluminum silicate, aluminum titanate, and iron-chromium-aluminum alloy. Among these, silicon carbide or silicon-silicon carbide based composite material is particularly preferable. Since silicon carbide has a relatively high coefficient of thermal expansion, a honeycomb structure formed using silicon carbide as an aggregate may cause defects due to thermal shock when used, but the honeycomb structure of the present invention The structure is a structure in which a plurality of honeycomb segments are arranged adjacent to each other so that the side surfaces thereof are opposed to each other, and the opposing side surfaces are joined together by a joining portion, so that stress due to thermal expansion of silicon carbide is joined. It is relieved by the part, and the occurrence of defects in the honeycomb structure can be prevented.

  The honeycomb segment constituting the honeycomb structure of the present embodiment (partition walls constituting the honeycomb segment) is preferably porous. The porosity of the honeycomb segment is preferably 30 to 80%, and more preferably 40 to 65%. By setting the porosity in such a range, the pressure loss can be reduced while maintaining the strength. If the porosity is less than 30%, the pressure loss may increase. If the porosity exceeds 80%, the strength may decrease or the thermal conductivity may decrease. The porosity is a value measured with a mercury porosimeter.

  The honeycomb segment constituting the honeycomb structure of the present embodiment preferably has an average pore diameter of 5 to 50 μm, more preferably 7 to 35 μm. By setting the average pore diameter in such a range, particulate matter (PM) can be effectively collected. If the average pore diameter is less than 5 μm, clogging may easily occur due to particulate matter (PM). When the average pore diameter exceeds 50 μm, particulate matter (PM) may pass through without being collected by the filter. The average pore diameter is a value measured with a mercury porosimeter.

  When the material of the honeycomb segment constituting the honeycomb structure of the present embodiment is silicon carbide, the average particle diameter of the silicon carbide particles is preferably 5 to 100 μm. By setting it as such an average particle diameter, there exists an advantage that it is easy to control to the porosity and pore diameter suitable for a filter. If the average particle size is smaller than 5 μm, the pore diameter may be too small, and if it is larger than 100 μm, the porosity may be too large. If the pore diameter is too small, clogging may easily occur due to particulate matter (PM), and if the porosity is too large, pressure loss may increase. The average particle diameter of the raw material is a value measured by a method based on JIS R 1629.

  The cell shape of the honeycomb segment constituting the honeycomb structure of the present embodiment (cell shape in a cross section perpendicular to the cell extending direction (cell extending direction) of the honeycomb structure) is a quadrangle, a hexagon or an octagon. A square or a rectangle is more preferable. Further, a structure in which octagonal cells having a large cross-sectional area and square cells having a small cross-sectional area are alternately arranged in a cross section orthogonal to the central axis direction (cell extending direction) of the honeycomb structure is also a preferable aspect. . Thus, when the honeycomb segment has a structure in which octagonal cells having a large cross-sectional area and square cells having a small cross-sectional area are alternately arranged, the honeycomb segment is cut off at the end surface on the inlet side of the fluid (exhaust gas). It is preferable to plug the opening of a rectangular cell having a small area and plug the opening of an octagonal cell having a large cross-sectional area at the end face on the outlet side of the fluid (exhaust gas). As a result, exhaust gas is allowed to flow from the opening of the octagonal cell having a large cross-sectional area (opening where no plugging portion is provided) on the end face on the inlet side of the fluid (exhaust gas), and the porous partition wall is formed. It is possible to allow the exhaust gas to be discharged from the opening of the rectangular cell having a small cross-sectional area (opening where the plugging portion is not provided). As a result, particulate matter in the exhaust gas can be collected on the partition wall surface having a large surface area inside the octagonal cell having a large cross-sectional area. Blockage of the octagonal cells) can be suppressed.

  The cross-sectional shape of the octagonal cell having a large cross-sectional area is not limited to an octagon, and may be a quadrangle or the like, and “a quadrangle whose corners are arc-shaped” is also a preferable aspect. The area of a cell having a large cross-sectional area (for example, an octagonal cell having a large cross-sectional area) is 1.2 to 2.5 times the area of a cell having a small cross-sectional area (for example, a square cell having a small cross-sectional area). It is preferable. If it is smaller than 1.2 times, the blocking effect of the inflow side cell (cell having a large cross-sectional area) may be lowered. If it is larger than 2.5 times, the cross-sectional area of the cell on the outflow side (cell having a small cross-sectional area) becomes small, so that the pressure loss may increase.

  In the honeycomb structure 100 of the present embodiment, the cell width W (see FIG. 3) is preferably 0.5 to 2.5 mm in the cross section orthogonal to the cell extending direction, and 0.8 More preferably, it is -2.0 mm. If the width W of the cell is smaller than 0.5 mm, the pressure loss when treating the exhaust gas may be reduced. When the width W of the cell is larger than 2.5 mm, the area of the partition wall for treating the exhaust gas becomes small, and the ability to treat the exhaust gas may be reduced.

  In the honeycomb structure 100 of the present embodiment, the partition wall thickness T (see FIG. 3) is preferably 0.2 to 0.5 mm, and more preferably 0.25 to 0.45 mm. Further preferred. When the partition wall thickness T is less than 0.2 mm, the strength of the honeycomb structure may be lowered. When the partition wall thickness T is larger than 0.5 mm, the area of the partition wall for treating the exhaust gas becomes small, the ability to treat the exhaust gas may decrease, and the pressure loss when the exhaust gas is treated increases. There is.

In the honeycomb structure 100 of the present embodiment, the cell density of the honeycomb segment is preferably 15.5 to 62.0 cells / cm ² (100 to 400 cells / inch ² ), 23.2 More preferably, it is 54.3 cells / cm ² (150 to 350 cells / inch ² ). If it is smaller than 15.5 cells / cm ² (100 cells / inch ² ), the partition wall thickness may be too thick, or the cell width may be too large. If it is larger than 62.0 cells / cm ² (400 cells / inch ² ), the partition wall thickness may be too thin, or the cell width may be too small.

Further, in the cross section perpendicular to the cell extending direction of the honeycomb structure of the present embodiment, the number of the arranged honeycomb segments is preferably 6 to 144, and more preferably 16 to 100. . The size of the honeycomb segment, the area of the cross section perpendicular to the cell extending direction is preferably 3～25Cm ^2, and further preferably from 9~21cm ^2. If it is smaller than 3 cm ² , the pressure loss when gas flows through the honeycomb structure may be increased, and if it is larger than 25 cm ² , the honeycomb segment damage prevention effect may be decreased.

  As shown in FIGS. 2, 4 and 5, the honeycomb structure of the present embodiment includes an opening of a predetermined cell 1 and an end face on the fluid outlet side of the honeycomb segment 4 on the end face 11 on the fluid inlet side. A plugging portion 6 is provided in the opening of the remaining cell 1 in FIG. The predetermined cells 1 and the remaining cells 1 are preferably arranged alternately so that a checkerboard pattern is formed on the end face of the honeycomb segment. FIG. 5 is a schematic view showing a part of a cross section of the honeycomb segment constituting one embodiment of the honeycomb structure of the present invention parallel to the cell extending direction.

  The joint portion 13 constituting the honeycomb structure of the present embodiment is disposed between adjacent honeycomb segments, and the honeycomb segments are joined by the joint portion 13. It is preferable that the joining part 13 is arrange | positioned in the whole side surface which the adjacent honeycomb segment opposes. The material of the joint portion 13 is preferably a material obtained by adding water to an inorganic raw material such as inorganic fiber, colloidal silica, clay, or SiC particles, and adding an additive such as an organic binder, a foamed resin, or a dispersant. .

  The thickness of the joint portion 13 is preferably 0.2 to 2.0 mm, and more preferably 0.5 to 1.5 mm. When the thickness is less than 0.2 mm, the force for joining the honeycomb segments may be weakened, and the adjacent honeycomb segments may be in contact with each other. If it is thicker than 2.0 mm, the area of the joint portion 13 becomes large in the cross section orthogonal to the direction in which the exhaust gas passes (cell extending direction), and thus pressure loss may increase when the exhaust gas flows. Note that the thickness of the joint portion 13 is the distance between adjacent honeycomb segments.

  The honeycomb structure of the present embodiment may include an outer peripheral portion formed so as to surround the whole of the plurality of honeycomb segments 4 (the plurality of joined honeycomb segments 4). By providing the outer peripheral portion, unevenness on the outer periphery of the honeycomb structure can be reduced. The thickness of the outer peripheral portion is preferably 0.1 to 4.0 mm, and more preferably 0.3 to 1.0 mm. If it is thinner than 0.1 mm, cracks are likely to occur when outer periphery coating is performed. If it is thicker than 4.0 mm, pressure loss may increase when exhaust gas flows.

  The overall size of the honeycomb structure of the present embodiment is not particularly limited, and can be a desired size. Specifically, the length of one side of the bottom surface of the honeycomb structure is preferably 80 to 300 mm, and more preferably 120 to 250 mm. Further, the length of the honeycomb structure in the cell extending direction is preferably 100 to 400 mm, and more preferably 115 to 310 mm.

  In another embodiment of the honeycomb structure of the present invention, as shown in FIG. 6, in one embodiment of the honeycomb structure of the present invention, the honeycomb structure is arranged at four corners in the overall shape in a cross section perpendicular to the cell extending direction. Among the corner portions 7 of the honeycomb segment 4 formed, the corner portion 7R forming the vertex 21 (the vertex in the overall shape of the honeycomb structure 101) has an arc shape having a radius of “length exceeding the length of 3 cell pitch” It is formed. In the honeycomb structure 101 of the present embodiment, the shape of the honeycomb segments 4 arranged at the four corners in the overall shape is different from the shape of the honeycomb segments 4 other than the honeycomb segments 4 arranged at the four corners. That is, in the cross section orthogonal to the cell extending direction, the radius of the arc of the corner portion 7R located at the apex 21 of the honeycomb segment 4 arranged at the four corners of the honeycomb structure 101 is the corner of the “other honeycomb segment 4”. It is formed larger than the radius of the arc of the portion 7r. FIG. 6 is a schematic view showing a cross section orthogonal to the cell extending direction of another embodiment of the honeycomb structure of the present invention.

  Thus, in the cross section orthogonal to the cell extending direction, only the radius of the arc of the corner portion 7R located at the apex 21 of the honeycomb segment 4 arranged at the four corners of the honeycomb structure 101 is “other honeycomb segment 4. Is formed larger than the radius of the arc of the corner portion 7r, when the honeycomb structure is used while being accommodated in a can body or the like with a cushion material or the like disposed on the side surface, It is possible to more effectively prevent a gap from being formed between the four apexes (corners) and the cushioning material, and it is possible to more effectively prevent the exhaust gas from leaking. This is because in the cross section orthogonal to the cell extending direction, only the radius of the arc of the corner portion 7R located at the vertex 21 of the honeycomb segment 4 arranged at the four corners of the honeycomb structure 101 is increased. This is because the radius of the circular arc of the corner 7R positioned can be more adapted to the characteristics such as the material of the cushion material and the hardness.

  Still another embodiment of the honeycomb structure of the present invention is, as shown in FIG. 7, in one embodiment of the honeycomb structure of the present invention described above, some honeycomb segments in a cross section orthogonal to the cell extending direction. The shape of 4 is different. Specifically, among the 4 × 4 honeycomb segments, four (one row) +4 (one row) honeycomb segments forming two opposing sides of the honeycomb structure 102 are orthogonal to the cell extending direction. The cross-sectional shape is rectangular, and the other four (one row) +4 (one row) honeycomb segments have a square cross-sectional shape perpendicular to the cell extending direction. As described above, the honeycomb structure 102 of the present embodiment can appropriately change the shape of the honeycomb segment according to the use conditions. FIG. 7 is a schematic view showing a cross section perpendicular to the cell extending direction of still another embodiment of the honeycomb structure of the present invention.

(2) Manufacturing method of honeycomb structure:
Next, a manufacturing method of an embodiment of the honeycomb structure of the present invention will be described.

(2-1) Production of honeycomb segment;
First, a binder, a surfactant, a pore former, water and the like are added to a ceramic raw material to form a forming raw material. Ceramic raw materials include silicon carbide, silicon-silicon carbide composite material, cordierite, mullite, alumina, spinel, silicon carbide-cordierite composite material, lithium aluminum silicate, aluminum titanate, iron-chromium-aluminum alloy It is preferably at least one selected from the group consisting of Among these, silicon carbide or silicon-silicon carbide based composite material is preferable. When a silicon-silicon carbide based composite material is used, a mixture of silicon carbide powder and metal silicon powder is used as a ceramic raw material. The content of the ceramic raw material is preferably 30 to 90% by mass with respect to the entire forming raw material.

  Examples of the binder include methyl cellulose, hydroxypropoxyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyvinyl alcohol. Among these, it is preferable to use methyl cellulose and hydroxypropoxyl cellulose in combination. The binder content is preferably 2 to 20% by mass with respect to the entire forming raw material.

  The water content is preferably 5 to 50 mass% with respect to the entire forming raw material.

  As the surfactant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the surfactant is preferably 0 to 5% by mass with respect to the entire forming raw material.

  The pore former is not particularly limited as long as it becomes pores after firing, and examples thereof include starch, foamed resin, water absorbent resin, silica gel and the like. The pore former content is preferably 0 to 20% by mass with respect to the entire forming raw material.

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

  Next, the kneaded material is extruded to form a plurality of honeycomb formed bodies. In extrusion molding, it is preferable to use a die having a desired segment shape, segment arrangement, cell shape, partition wall thickness, cell density, and the like. As the material of the die, a cemented carbide which does not easily wear is preferable. The honeycomb formed body has porous partition walls that define and form a plurality of cells serving as fluid flow paths, and an outer peripheral wall located at the outermost periphery.

  The partition wall thickness, cell density, outer peripheral thickness, etc. of the honeycomb molded body can be appropriately determined in accordance with the structure of the honeycomb structure of the present invention to be manufactured in consideration of shrinkage during drying and firing.

  The obtained honeycomb formed body is preferably dried before firing. The drying method is not particularly limited, and examples thereof include an electromagnetic heating method such as microwave heating drying and high-frequency dielectric heating drying, and an external heating method such as hot air drying and superheated steam drying. Among these, the entire molded body can be dried quickly and uniformly without cracks, and after drying a certain amount of moisture with an electromagnetic heating method, the remaining moisture is dried with an external heating method. It is preferable to make it. As drying conditions, it is preferable to remove moisture of 30 to 90% by mass with respect to the amount of moisture before drying by an electromagnetic heating method, and then to make the moisture to 3% by mass or less by an external heating method. As the electromagnetic heating method, dielectric heating drying is preferable, and as the external heating method, hot air drying is preferable.

  Next, when the length of the honeycomb formed body in the cell extending direction is not a desired length, it is preferable to cut both end faces (both end portions) to a desired length. The cutting method is not particularly limited, and examples thereof include a method using a circular saw cutting machine.

  Next, the honeycomb fired body is preferably fired to produce a honeycomb fired body. In order to remove the binder or the like before firing, it is preferable to perform temporary firing. Pre-baking is preferably performed at 400 to 500 ° C. for 0.5 to 20 hours in an air atmosphere. The method of temporary baking and baking is not particularly limited, and baking can be performed using an electric furnace, a gas furnace, or the like. Firing conditions are preferably heated at 1300 to 1500 ° C. for 1 to 20 hours in an inert atmosphere such as nitrogen or argon.

  Next, plugging portions are formed in the openings of predetermined cells on the end face on the fluid inlet side of the obtained honeycomb fired body and the openings of the remaining cells on the end face on the outlet side of the fluid. Is made. A method for forming the plugged portion is not particularly limited, and examples thereof include the following methods. After the sheet is attached to one end face of the honeycomb fired body, a hole is opened at a position corresponding to a cell where a plugging portion of the sheet is to be formed. Then, in the plugging slurry in which the constituent material of the plugging portion is slurried, the honeycomb fired body is immersed in the end face on which the sheet is pasted, and an attempt is made to form the plugging portion through holes formed in the sheet. The plugging slurry is filled in the opening of the cell.

  And about the other end surface of the honeycomb fired body, plugging portions are formed in the same manner as the method in which the plugging portions are formed on the one end surface with respect to the cells not plugged on one end surface. (Fill with plugging slurry). As the plugging slurry, it is preferable to use a slurry obtained by adding a binder such as methyl cellulose and a pore former to a ceramic raw material of a honeycomb formed body. After forming the plugged portion, it is preferable to perform baking under the same conditions as the above baking conditions. The plugging portion may be formed before firing the honeycomb formed body.

(2-2) Production of honeycomb structure;
A predetermined number of honeycomb segments are bonded with a bonding material and dried, and a plurality of honeycomb segments are arranged adjacent to each other such that the side surfaces face each other, and the opposite side surfaces are bonded to each other by the bonding portion. A honeycomb structure is formed. It is preferable that the joining portion is disposed on the entire side surfaces facing each other. The joined portion plays a role of buffering (absorbing) a volume change when the honeycomb segments are thermally expanded and contracted, and also serves to join the honeycomb segments.

  The method for applying the bonding material to the side surfaces of the honeycomb segments is not particularly limited, and a method such as brush coating can be used.

  Examples of the bonding material include a slurry obtained by adding water to an inorganic raw material such as inorganic fiber, colloidal silica, clay, and SiC particles and adding an additive such as an organic binder, a foamed resin, and a dispersant, and kneading. it can.

  The honeycomb structure may be bonded with a bonding material and dried, and then outer periphery coating may be performed to form a honeycomb structure having an outer peripheral portion disposed on the outermost periphery. By disposing the outer peripheral portion, the unevenness on the outer periphery of the honeycomb structure can be further reduced. As a method of the outer periphery coating treatment, a method of applying an outer periphery coating material to the outermost periphery of the joined honeycomb segment assembly and drying it can be mentioned. As the outer periphery coating material, a mixture of inorganic fiber, colloidal silica, clay, SiC particles, organic binder, foamed resin, dispersant, water, or the like can be used. Moreover, the method of applying the outer periphery coating material is not particularly limited, and examples thereof include a method of coating the honeycomb structure with a rubber spatula while rotating on the potter's wheel.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

( Reference Example 1)
As ceramic raw materials, SiC powder and metal Si powder are mixed at a mass ratio of 80:20. To this, methylcellulose and hydroxypropoxymethylcellulose are formed as molding aids, starch and water-absorbing resin, surfactant and water are used as pore formers. The kneaded material was added and kneaded, and a square columnar kneaded material was produced with a vacuum kneader.

  Using the obtained square columnar clay, an extrusion molding machine was used to form a honeycomb molded body with porous partition walls that formed a plurality of cells that became fluid flow paths and an outer peripheral wall located at the outermost periphery. . The obtained honeycomb formed body was dried by high-frequency dielectric heating and then dried at 120 ° C. for 2 hours using a hot air dryer, and both end surfaces were cut by a predetermined amount.

  The obtained honeycomb formed body was dried at 120 ° C. for 5 hours using a hot air dryer, and then degreased at about 450 ° C. for 5 hours using an air furnace equipped with a deodorizing apparatus in an air atmosphere. Firing at about 1450 ° C. for 5 hours in an inert atmosphere yielded a porous honeycomb fired body in which SiC crystal particles were bonded with Si. The honeycomb fired body had an average pore diameter of 13 μm and a porosity of 41%. The average pore diameter and porosity are values measured with a mercury porosimeter.

For the obtained honeycomb fired body, after forming plugged portions in the opening portions of the predetermined cells on the end surface on the inlet side of the fluid and the opening portions of the remaining cells on the end surface on the outlet side of the fluid, The honeycomb fired body was fired under the same conditions to form honeycomb segments. The obtained honeycomb segment was a square having a bottom surface of 36.2 mm on a side and a length in the cell extending direction of 200 mm. The cell density was 46 cells / cm ² (300 cells / square inch), and the partition wall thickness was 0.31 mm. The cell pitch was 1.47 mm. Further, four corners of the obtained honeycomb segment in a cross section perpendicular to the cell extending direction were formed in an arc shape having a radius of 1.5 mm.

  The obtained honeycomb segments were joined with a joining material so as to form a 4 × 4 array as in the honeycomb structures shown in FIGS. 1 and 2, and dried to obtain a honeycomb structure. As the bonding material, a material containing 30% by mass of water, 30% by mass of aluminosilicate inorganic fibers, and 30% by mass of SiC particles with respect to the entire bonding material was used. Other components contained in the bonding material were an organic binder, a foamed resin, and a dispersant. The thickness of the bonding material was 1.0 mm.

  The obtained honeycomb structure had a square columnar shape with a bottom having a square with a side of 147.8 mm and a length in the cell extending direction of 200 mm.

  The obtained honeycomb structure was evaluated for “outer periphery irregularities”, “exhaust gas leakage”, and “pressure loss” by the following methods. The results are shown in Table 1.

  In Table 1, “cell structure” indicates cell density. Further, “all the same” in the column “structure of honeycomb segment” indicates that all honeycomb segments constituting the honeycomb structure have the same shape and the same production lot. Here, when the same raw material lot is prepared, mixed and kneaded, extruded, dried, and continuously fired, the production lot is the same. Further, “difference only at the four corners” in the column of “structure of honeycomb segment” indicates that the four honeycomb segments located at the four corners of the honeycomb structure have a shape different from the honeycomb segments other than the four corners. The four honeycomb segments located at the four corners of the honeycomb structure are the same production lot, and the honeycomb segments other than the four corners are the same production lot. Further, the “combination of the bottom square and the bottom rectangle” is such that, as shown in FIG. 7, in the cross section orthogonal to the cell extending direction, the honeycomb segments each having the bottom rectangular shape along the two opposite sides of the honeycomb structure are 4 This means a structure in which 8 pieces of honeycomb segments having a square bottom surface are arranged in two rows in between. In addition, “two types of lots” means that the honeycomb segments constituting the honeycomb structure have the same shape but the honeycomb segments of two types of production lots are used.

In addition, when one numerical value “X” is described in the column of “the shape of the bottom surface of the honeycomb segment other than the four corners” (for example, X = 36.2 in the reference example 1), the four corners of the honeycomb structure This means that the bottom surface of the honeycomb segment constituting the other is a square with one side “X (mm)”. When the product is described in the form of the product of two numerical values “Y × Z” (for example, Y × Z = 36.2 × 18.0 in Reference Example 3 ), the structure other than the four corners of the honeycomb structure is formed. This means that the bottom surface of the honeycomb segment is a rectangle of “Y (mm) × Z (mm)” (for example, in Reference Example 3 , a rectangle of “36.2 mm × 18.0 mm”). When the “structure of the honeycomb segment” is “all the same”, the “shape of the bottom surface of the honeycomb segment at the four corners of the honeycomb structure” is also the same as the “shape of the bottom surface of the honeycomb segment other than the four corners”. Further, when the column of “structure of honeycomb segment” is “combination of bottom square and bottom rectangle”, since the honeycomb segment is arranged as shown in FIG. 7, “the shape of the bottom surface of the honeycomb segment other than the four corners” Two of “36.1” and “36.2 × 18.3” are described.

Further, when one numerical value “X” is described in the column of “bottom shape of honeycomb segment at four corners” (for example, X = 36.2 in Example 3 ), the four corners of the honeycomb structure are defined. It means that the bottom surfaces of the four honeycomb segments that are formed are squares with one side “X (mm)”. And when it is described in the form of the product of two numerical values “Y × Z” (for example, Y × Z = 36.2 × 18.3 in Reference Example 4 ), the four corners of the honeycomb structure are formed. This means that the bottom surface of the honeycomb segment is a rectangle of “Y (mm) × Z (mm)” (for example, in Reference Example 4 , a rectangle of “36.2 mm × 18.3 mm”).

  Further, the column of “radius of corner R positioned at the apex” in “radius of arc-shaped corner” indicates the “circle forming the apex of the honeycomb structure” of the honeycomb segment positioned at the four corners of the honeycomb structure. The radius of the arc of the “arc-shaped corner” is shown. Note that “C chamfering: 0.2” means a dimension in which a corner is cut with a triangle (an isosceles triangle) whose one side (side across the corner) is 0.2 mm with the corner as a base point. Further, in the “radius of the corner r located at a portion other than the apex” in the “radius of the arc-shaped corner”, the “honeycomb structure” is included in the corners of all the honeycomb segments constituting the honeycomb structure. The radius of the corner excluding the “corner located at the apex of the body” is shown.

(Roughness of the outer periphery)
The uneven size of the outer periphery of the honeycomb structure was measured by enlarging with a microscope.

(Exhaust gas leakage)
As shown in FIG. 8, the honeycomb structure is placed in the can body 32 with the cushion material 31 arranged on the outer periphery. Then, the can body in which the honeycomb structure is inserted is connected to an exhaust pipe of a 4-cylinder direct injection diesel engine (displacement: 2000 cc). Then, the operation of “running the diesel engine for 90 minutes to collect the particulate matter in the honeycomb structure and then“ regenerate the combusted particulate matter ”is repeated 500 times, and the cushion material and Observe the adherence of particulate matter to the can. The case where particulate matter adhered to the cushion material or the can body was rejected as “attached”. Adhesion “None” was accepted. Note that a non-inflatable mat was used as the cushion material 31. As the can body, a cylindrical member made of stainless steel was used.

(Pressure loss)
Air (25 ° C.) was allowed to flow through the honeycomb structure at a rate of 10 Nm ³ / min, and the air pressure was measured at the end surface portion on the inflow side of the honeycomb structure and the end surface portion on the outflow side of the honeycomb structure. A value obtained by subtracting the outlet pressure from the inlet pressure was defined as a pressure loss (initial pressure loss).

(Examples 1 to 9 , Reference Examples 2 to 5, Comparative Examples 1 to 7)
A honeycomb structure was manufactured in the same manner as in Reference Example 1 except that the conditions of the honeycomb segments and the joints were changed as shown in Table 1. In the same manner as in the case of Reference Example 1, evaluation of “outer periphery irregularities”, “exhaust gas leakage” and “pressure loss” was performed by the above method. The results are shown in Table 1.

From Table 1, it can be seen that the honeycomb structures of Examples 1 to 8 and Reference Examples 1 to 5 have small irregularities on the outer periphery, no leakage of exhaust gas, and small pressure loss. It can be seen that the honeycomb structures of Comparative Examples 1, 2, 5 and 6 have exhaust gas leakage because of the small arcs at the corners of the honeycomb segments. Further, in the honeycomb structure of Comparative Example 3, it is found that the exhaust gas leaks because the corners of the honeycomb segment are “C chamfer: 0.2”. Further, it can be seen that the honeycomb structures of Comparative Examples 4 and 7 have large pressure loss because the corners of all the honeycomb segments are in a large arc shape.

  The honeycomb structure of the present invention can be suitably used as a carrier for a catalyst device or a filter used for environmental measures or recovery of specific materials in various fields such as chemistry, electric power, and steel. .

1: cell, 2: partition wall, 3: outer peripheral wall, 4: honeycomb segment, 5: side surface, 6: plugging portion, 7, 7r, 7R: corner portion (corner portion of honeycomb segment), 11: inlet of fluid Side end face, 12: end face on the fluid outlet side, 13: junction, 21: apex, 22: corner position (corner position of honeycomb structure), 31: cushion material, 32: can body, 100, 101 , 102: honeycomb structure, L: length of one side of honeycomb segment, P: cell pitch, T: thickness of partition wall, W: width of cell.

Claims (3)

A porous partition wall for partitioning a plurality of cells serving as fluid flow paths and an outer peripheral wall located at the outermost periphery; an opening portion of a predetermined cell on an end surface on the fluid inlet side; and A plurality of rectangular pillar-shaped honeycomb segments having plugged portions at the openings of the remaining cells on the end face,
The plurality of honeycomb segments have a cell density of 15.5 to 62.0 cells / cm ² , and the outer peripheral wall is a quadrangle having arc-shaped corners in a cross section orthogonal to the cell extending direction. Yes,
The plurality of honeycomb segments are arranged adjacent to each other so that the side surfaces thereof are opposed to each other, and the opposing side surfaces are joined by a joint portion,
In the cross section orthogonal to the cell extending direction, the overall shape is a quadrangle, and among the corners of the honeycomb segment arranged at the four corners of the overall shape, the corners forming the vertices in the overall shape are 2 cell pitches Is formed in a circular arc shape having a radius equal to or greater than the length of one side of the honeycomb segment,
In a cross section orthogonal to the cell extending direction, all the corners of the honeycomb segment excluding the honeycomb segments arranged at the four corners are in an arc shape having a radius of 1 cell pitch or more and less than 3 cell pitch lengths. Formed,
In the cross section orthogonal to the cell extending direction, the radius of the arc-shaped corner portion forming the apex in the overall shape is all the arc-shaped corner portions of the honeycomb segment excluding the honeycomb segments arranged at the four corners. Honeycomb structure larger than the radius .   The honeycomb structure according to claim 1, wherein all of the honeycomb segments excluding the honeycomb segments arranged at the four corners of the plurality of honeycomb segments have the same shape.   The honeycomb structure according to claim 1, wherein all of the plurality of honeycomb segments have the same shape.

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