JP2014188400A - Honeycomb filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique relating to a honeycomb filter capable of collecting a large amount of particulate matter (PM) and suppressing the breakage of a partition wall.SOLUTION: In a honeycomb filter provided with a plurality of honeycomb segments 1 having a partition wall dividing and forming a plurality of first cells 11 and a plurality of second cells 15, the opening area of the first cells 11 is smaller than or equal to that of the second cells 15. In the honeycomb segment 1, a difference value Bbetween a distance Abeing a distance from a side surface 21 to a partition wall 9 at the far side of the second cells in an outer peripheral region 25 and a distance Abeing a distance from the side surface 21 to the partition wall 9 of the first cells at a far side is smaller than a difference value Bbetween the same distance Aand the same distance Ain a center region 27.

Description

  The present invention relates to a honeycomb filter. More specifically, the present invention relates to a honeycomb filter that can collect a large amount of ash and particulate matter (PM) and can suppress breakage of partition walls during canning.

  An exhaust gas discharged from an internal combustion engine such as a diesel engine or various combustion apparatuses contains a large amount of particulate matter mainly composed of soot. When this particulate matter is released into the atmosphere as it is, environmental pollution is caused. Therefore, an exhaust gas flow path from an internal combustion engine or the like is generally equipped with a filter for collecting the particulate matter. .

  As such an exhaust gas purifying filter, for example, a plug having a honeycomb structure portion having porous partition walls for defining cells and a plurality of plugging portions for sealing one end portion of the cells. A stop honeycomb structure can be mentioned.

  In this plugged honeycomb structure, by providing the plugging portion, a process in which the exhaust gas passes through the partition walls is incorporated in the exhaust gas passage process. In the process of exhaust gas passing through the partition walls, particulate matter contained in the exhaust gas is captured by the partition walls. Therefore, according to the plugged honeycomb structure, the particulate matter in the exhaust gas can be reduced.

  Furthermore, for plugged honeycomb structures, cells with a large cross-sectional area (large cross-sectional area cells) and cells with a small cross-sectional area (small cross-sectional area cells) are alternately arranged to collect a large amount of PM. There has been reported an improved plugged honeycomb structure that has been devised (for example, Patent Document 1). Further, in this improved plugged honeycomb structure, the end on the inflow side is opened and the end on the outflow side is sealed in the large cross section cell, and the end on the inflow side is sealed in the small cross section cell. Stop and open the end on the outflow side. Therefore, in the improved plugged honeycomb structure, exhaust gas is allowed to flow into the large cross-sectional area cell, and PM is collected by the partition wall surrounding the large cross-sectional area cell. The partition wall surrounding the large cross-sectional area cell has a larger surface area than the partition wall surrounding one cell in the conventional plugged honeycomb structure (plugged honeycomb structure composed of cells having the same cross-sectional area). . Therefore, in the improved plugged honeycomb structure, a large amount of PM can be collected, and an increase in pressure loss in a situation where PM is collected can be suppressed.

  Further, for the above-described improved plugged honeycomb structure, a technique has been proposed in which the structural strength is increased by a plugged honeycomb joined body in which a plurality of honeycomb segments are joined.

International Publication No. 2004/024294

  However, in each of the honeycomb segments in the above-mentioned plugged honeycomb joined body, the partition wall has a zigzag shape due to a special form in which the large cross-sectional area cells and the small cross-sectional area cells are alternately arranged. Therefore, when the plugged honeycomb joined body is stored in the can while being pressed (canned), when a force for crushing the plugged honeycomb joined body from the side is applied, the partition walls of the outer peripheral portion of each honeycomb segment Damage is likely to occur.

  In view of the above problems, an object of the present invention is to provide a technology related to a honeycomb filter that can collect a large amount of particulate matter (PM) and can suppress breakage of partition walls.

  The present invention is the following honeycomb filter.

[1] A plurality of honeycomb segments having partition walls that partition and form a plurality of cells serving as fluid flow paths extending from the inflow end surface to the outflow end surface, and predetermined cells among the plurality of cells formed in the honeycomb segment A plurality of plugging portions for sealing the opening on the inflow end face side of a certain first cell and the opening on the outflow end face side of the second cell which is a remaining cell among the plurality of cells; A bonding layer for bonding at least a part of the side surfaces of each of the honeycomb segments, wherein the honeycomb cells are alternately arranged with the first cells and the second cells, and the honeycomb segments are arranged from the side surfaces of the honeycomb segments. The outer peripheral region forming the cells arranged in the first to third rows and the central region forming the cells arranged in the fourth and subsequent rows from the side surface, and in the central region In the cross section perpendicular to the cell extending direction, the opening area of the first cell is smaller than the opening area of the second cell, and in the outer peripheral region, in the cross section perpendicular to the cell extending direction, The opening area of the first cell is equal to or smaller than the opening area of the second cell, and in the outer peripheral region, the side surface from the portion farthest from the side surface of the honeycomb segment among the partition walls defining the first cell. the distance to the distance a _1, and a distance to the side surface and the distance a ₂ from the farthest portion from the side surface of the honeycomb segments among the barrier ribs partitioning the second cell, in the central region, the first a distance a ₃ a distance to the side from the farthest portion from the side surface of the honeycomb segments among the barrier ribs partitioning the cell, Gu said second cell When the distance A ₄ the distance to the side from the farthest portion from the side surface of the honeycomb segments among the partition walls, the value of the difference between the distance A ₂ in the same row as counted from the side surface and the distance A ₁ A honeycomb filter in which B 2 _O is smaller than a difference value B _C between the distance A ₄ and the distance A ₃ in the same row from the side surface.

[2] The honeycomb filter according to [1] the value _{B O} is zero.

[3] The honeycomb filter according to [1] or [2], wherein the opening area of the first cell is equal to the opening area of the second cell in the outer peripheral region.

[4] The [1] to [3], wherein the opening area of the first cell and the opening area of the second cell in the outer peripheral region are equal to or less than the opening area of the first cell in the central structure portion. The honeycomb filter according to any one of the above.

[5] only in the first row from the side, the honeycomb filter according to the said value B _O is zero [1].

[6] The honeycomb filter according to [1] or [5], wherein the opening area of the first cell is equal to the opening area of the second cell only in the first row from the side surface.

[7] The opening area of the first cell and the opening area of the second cell are not more than the opening area of the first cell in the central region only in the first row from the side surface. ], [5], The honeycomb filter according to any one of [6].

According to the honeycomb filter of the present invention, a large amount of particulate matter (PM) can be collected because the particulate matter is supplemented by the partition wall surrounding the second cell having an opening area larger than or equal to that of the first cell. It is. Further, according to the honeycomb filter of the present invention, the difference value B _O between the distance A ₂ and the distance A ₁ in the outer peripheral region of the honeycomb segment is greater than the difference value B _C between the distance A ₄ and the distance A ₃ in the central region. Is also small. As a result, in the honeycomb filter of the present invention, the wobbling width of the partition wall zigzag in the outer peripheral region of the honeycomb segment is reduced. As a result, according to the honeycomb filter of the present invention, it is possible to suppress partition wall breakage (particularly, partition wall buckling) even when force is applied to the honeycomb segment from the side.

It is a perspective view showing one embodiment of a honeycomb filter of the present invention. FIG. 2 is a perspective view of a honeycomb segment used in the honeycomb filter shown in FIG. 1. FIG. 3 is a schematic diagram showing a cross section of a part of the honeycomb segment shown in FIG. 2. It is the schematic diagram which expanded and showed a part of inflow end surface about the honeycomb segment which comprises one Embodiment of the honeycomb filter of this invention. It is the schematic diagram which expanded and showed a part of inflow end surface about the honeycomb segment which comprises other embodiment of the honeycomb filter of this invention. FIG. 6 is a schematic view showing an enlarged part of the inflow end surface of a honeycomb segment constituting still another embodiment of the honeycomb filter of the present invention. FIG. 6 is a schematic view showing an enlarged part of the inflow end surface of a honeycomb segment constituting still another embodiment of the honeycomb filter of the present invention. FIG. 6 is a schematic view showing an enlarged part of the inflow end surface of a honeycomb segment constituting still another embodiment of the honeycomb filter of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the present invention.

1. Honeycomb filter:
FIG. 1 is a perspective view of a honeycomb filter 50 according to an embodiment of the present invention as viewed from the inflow end face 3 side. As illustrated, the honeycomb filter 50 of the present embodiment includes a plurality of honeycomb segments 1. Furthermore, in the honeycomb filter 50 of the present embodiment, the side surfaces of the plurality of honeycomb segments 1 are bonded together via the bonding layer 23. In the honeycomb filter 50 of the present embodiment, the joined body in which the plurality of honeycomb segments 1 are joined has a cylindrical shape, and the outer peripheral wall 31 surrounds the outer circumference of the joined body.

  FIG. 2 is a perspective view of one honeycomb segment 1 used in the honeycomb filter 50 shown in FIG. FIG. 3 is a schematic diagram showing a cross section of a part of the honeycomb segment 1 shown in FIG. 2 [a cross section parallel to the cell extending direction Z (hereinafter simply referred to as “Z direction”)]. As shown in the figure, the honeycomb segment 1 used in the honeycomb filter 50 of the present embodiment has partition walls 9, and a honeycomb structure is formed by the partition walls 9. That is, in the honeycomb segment 1, the partition walls 9 define a plurality of cells 7 extending from the inflow end surface 3 to the outflow end surface 5. In the honeycomb segment 1, the outer periphery is surrounded by the side wall 33. In the honeycomb segment 1, in a cross section perpendicular to the Z direction, the side wall 33 is a quadrangular shape constituted by a pair of sides parallel to the X direction and a pair of sides parallel to the Y direction (direction perpendicular to the X direction and the Z direction). Presents a cross-sectional shape. In the honeycomb segment 1, flat surfaces are formed at both ends in the Z direction. That is, in the honeycomb segment 1, one of both ends in the Z direction is the inflow end surface 3 and the other is the outflow end surface 5.

  Further, as shown in FIG. 3, in the honeycomb segment 1, a plurality of cells 7 are composed of first cells 11 and second cells 15, and the first cells 11 and the second cells 15 are alternately arranged. Has been. Further, in the honeycomb segment 1, the first cell 11 has the opening on the inflow end face 3 side sealed by the plugging portion 19, while the second cell 15 has the opening on the outflow end face 5 side plugged. 19 is sealed.

  According to such an arrangement mode of the plugging portions 19, in the honeycomb segment 1, the gas G flows into the second cell 15 from the inflow end surface 3. Subsequently, since the end of the second cell 15 on the outflow end face 5 side is closed by the plugging portion 19, the gas G that has flowed into the second cell 15 is surrounded by the partition wall 9 surrounding the second cell 15. And flows to the adjacent first cell 11. At this time, the particulate matter (PM) contained in the gas G is captured by the partition walls 9. The gas G flowing into the first cell 11 is discharged from the opening on the outflow end face 5 side of the first cell 11.

  In particular, in the honeycomb segment 1, in the cross section perpendicular to the Z direction, the opening area of the first cell 11 is smaller than the opening area of the second cell 15 in the central region 27, and the opening area of the first cell 11 in the outer peripheral region 25 is the first. The opening area of the two cells 15 is equal to or smaller than that.

  Due to the characteristics related to the opening areas of the first cell 11 and the second cell 15 as described above, in the honeycomb segment 1, the partition wall 9 surrounding the second cell 15, in other words, the partition wall 9 responsible for capturing the particulate matter has a large surface area. Become. Therefore, according to the honeycomb segment 1, a large amount of PM can be collected, and pressure loss in a situation where PM is collected can be suppressed. As a result, when the honeycomb filter 50 of the present embodiment is used, since the plurality of honeycomb segments 1 are provided, a large amount of particulate matter contained in the gas G is collected, and the gas G is effectively collected. It can be purified.

  In this specification, “the opening area of the first cell 11” means a cross-sectional area of the first cell 11 in a cross section perpendicular to the Z direction. Further, in this specification, “the opening area of the second cell 15” means a cross-sectional area of the second cell 15 in a cross section perpendicular to the Z direction.

  In the present specification, the “center region 27” means a region that forms the cells 7 arranged in the fourth and subsequent rows from the side surface 21 (the outer surface of the side wall 33) of the honeycomb segment 1. In the present specification, the “outer peripheral region 25” means a region that forms the cells 7 arranged in the first to third rows from the side surface 21 of the honeycomb segment 1.

FIG. 4 is a schematic view showing an enlarged part of the inflow end face 3 of the honeycomb segment 1a constituting one embodiment of the honeycomb filter of the present invention. The part shown in FIG. 4 corresponds to the part of the frame α in FIG. First, prior to the description of the honeycomb segment 1a, terms are defined with reference to FIG. In the outer peripheral region 25, the distance from the portion farthest from the side surface 21 to the side surface 21 in the partition wall 9 that partitions the first cell 11 is a distance A ₁ . In the outer peripheral region 25, the distance to the side surface 21 a distance A ₂ from the farthest portion from the side surface 21 of the partition wall 9 which partitions the second cell 15. In the central region 27, the distance A ₃ a distance to the side surface 21 from the farthest portion from the side surface 21 of the partition wall 9 which partitions the first cell 11. In the central region 27, the distance to the side surface 21 a distance A ₄ from the farthest portion from the side surface 21 of the partition wall 9 which partitions the second cell 15.

In the honeycomb segment 1a, the difference value B _O between the distance A ₂ and the distance A ₁ from the side surface 21 to the same row is smaller than the difference value B _C between the distance A ₄ and the distance A ₃ from the side surface 21 to the same row. . Therefore, in the honeycomb segment 1a, although the partition wall 9 extending in the X direction or the Y direction in the outer peripheral region 25 may be wavyly zigzag, the swing width is small. The partition wall 9 extending in the X direction or the Y direction in the outer peripheral region 25 is between the cell 7 in the first column and the cell 7 in the second column, and between the cell 7 in the second column and the third column. It is a partition wall 9 that separates between the cells 7 and between the cells 7 in the third column and the cells 7 in the fourth column. Therefore, even when a force to crush the honeycomb segment 1a from the side is applied, the partition wall 9 existing in the outer peripheral region 25 is unlikely to buckle, and consequently the partition wall 9 in the outer peripheral region 25 is damaged. It becomes possible to suppress. Referring to FIG. 4, in the honeycomb segment 1a, for example, the bending of the partition walls 9 at the intersection portion 35 where the first cells 11 and the second cells 15 intersect with each other becomes gentle. Therefore, according to the honeycomb segment 1a, even when compressive stress along the Y direction is generated in the partition wall 9, the partition wall 9 is prevented from being bent and damaged in the X direction.

In the honeycomb segment 1a, the cells 7 are arranged along the direction in which the side wall 33 extends, specifically, along the X direction and the Y direction, and the cross-sectional shape of the first cell 11 is an octagon, The cross-sectional shape is a quadrangle. “The cross-sectional shape of the first cell 11 is an octagon” means an octagon composed of four long sides extending in the X direction and the Y direction and a short side interposed between the long sides. is there. “The cross-sectional shape of the second cell 15 is a quadrilateral” means a quadrilateral composed of four sides extending in the X direction and the Y direction. In the honeycomb segments 1a, the distance A ₁ and the distance A ₃ is the cross section perpendicular to the Z direction, of the partition wall 9 which partitions the first cell 11, corresponding to the long side of the side away from the side surface 21 parallel to the Y-direction This is the distance from the part to be performed to the side surface 21. Further, in the honeycomb segments 1a, the distance A ₂ and the distance A _4, in the cross section perpendicular to the Z direction, of the partition wall 9 which partitions the second cell 15, on the far side of the side from the side 21 parallel to the Y-direction This is the distance from the corresponding part to the side surface 21.

FIG. 5 is a schematic view showing an enlarged part of the inflow end face 3 of a honeycomb segment 1b constituting another embodiment of the honeycomb filter of the present invention. The portion shown in FIG. 5 corresponds to the portion of the frame α in FIG. In the honeycomb segment 1b, the value B _O is smaller than the value B _C , and the distance A ₁ and the distance A ₂ in the same row from the side surface 21 are equal (in other words, the value B _O is zero). As described above, when the value B _O is smaller than the value B _C and the value B _O is zero, in the honeycomb segment 1b, the partition wall 9 extending in the X direction or the Y direction extends linearly in the outer peripheral region 25. As a result, even when a force to crush the honeycomb segment 1b from the side is applied, the partition wall 9 existing in the outer peripheral region 25 is less likely to buckle. Therefore, according to the honeycomb segment 1b, breakage of the partition wall 9 in the outer peripheral region 25 can be more reliably suppressed.

  Furthermore, as shown in FIG. 5, in the honeycomb segment 1 b, the opening area of the first cell 11 is equal to the opening area of the second cell 15 in the outer peripheral region 25. In the honeycomb segment 1b, the first cells 11 and the second cells 15 are alternately arranged along the X direction and the Y direction. Further, in the honeycomb segment 1b, the cross-sectional shapes of the first cell 11 and the second cell 15 are quadrangular in the outer peripheral region 25. Therefore, in the honeycomb segment 1b, in the outer peripheral region 25, the partition walls 9 extending in the direction from the side surface toward the center also extend linearly. As a result, in the honeycomb segment 1b, buckling is more unlikely to occur in the partition walls 9 existing in the outer peripheral region 25, and as a result, breakage of the partition walls 9 in the outer peripheral region 25 can be more reliably suppressed.

  FIG. 6 is a schematic view showing an enlarged part of the inflow end surface 3 of a honeycomb segment 1c constituting another embodiment of the honeycomb filter of the present invention. The portion shown in FIG. 6 corresponds to the portion of the frame α in FIG. In the honeycomb segment 1 c, the opening area of the first cell 11 and the opening area of the second cell 15 in the outer peripheral region 25 are equal to or smaller than the opening area of the first cell 11 in the central region 27. In the honeycomb segment 1c, the cell density is the same in both the central region 27 and the outer peripheral region 25, and the cells 7 (first cell 11 and second cell 15) are straight along the X direction and the Y direction. Are lined up. In such a configuration, when the opening area of the first cell 11 and the opening area of the second cell 15 in the outer peripheral region 25 are equal to or smaller than the opening area of the first cell 11 in the central region 27, the thickness of the partition wall 9 in the outer peripheral region 25. This is larger than the central region 27. Therefore, even when a force to crush the honeycomb segment 1c from the side is applied, the partition wall 9 existing in the outer peripheral region 25 is less likely to buckle. That is, according to the honeycomb segment 1c, it is possible to more reliably suppress the breakage of the partition walls 9 in the outer peripheral region 25.

FIG. 7 is a schematic view showing an enlarged part of the inflow end face 3 of a honeycomb segment 1d constituting still another embodiment of the honeycomb filter of the present invention. The portion shown in FIG. 7 corresponds to the portion of the frame α in FIG. In the honeycomb segment 1d, smaller than the value _{B O} value _{B C,} and the distance _{A 1} and the distance _{A 2} only at the first row from the side 21 is equal (in other words, the value _{B O} is zero). Thus, since the value B _O is smaller than the value B _C and the value B _O is zero only in the first column from the side surface 21, the honeycomb segment 1d has the cells 7 and the second column in the first column. A partition wall 9 separating the cell 7 extends linearly. As a result, even when a force to crush the honeycomb segment 1d from the side is applied, the partition wall 9 existing in the outer peripheral region 25 is less likely to be buckled. It is possible to more reliably suppress the breakage.

  In addition, in the honeycomb segment 1d, the opening areas of the second cells 15 in the second row and the third row from the side surface 21 are larger than the opening areas of the second cells 15 in the first row from the side surface 21. Therefore, according to the honeycomb segment 1d, as compared with the above-described honeycomb segment 1b, a large amount of particulate matter is collected by the partition walls 9 surrounding the second cells 15 in the second row and the third row, but the pressure loss is reduced. It is possible to suppress the increase.

  Further, in the honeycomb segment 1d, the opening area of the first cell 11 is equal to the opening area of the second cell only in the first row from the side surface 21. Furthermore, in the honeycomb segment 1d, the cross-sectional shapes of the first cells 11 and the second cells 15 are quadrangular only in the first row from the side surface 21. In the honeycomb segment 1d, since the opening area of the first cell 11 is equal to the opening area of the second cell only in the first row from the side surface 21, buckling in the partition wall 9 in the outermost peripheral portion where damage is most likely to occur is further increased. It becomes possible to suppress it reliably.

  FIG. 8 is a schematic view showing an enlarged part of the inflow end surface 3 of a honeycomb segment 1e constituting another embodiment of the honeycomb filter of the present invention. The part shown in FIG. 8 corresponds to the part of the frame α in FIG. In the honeycomb segment 1 e, the opening area of the first cell 11 and the opening area of the second cell 15 are not more than the opening area of the first cell 11 in the central region 27 only in the first row from the side surface 21. In the honeycomb segment 1e, the cell density is the same in both the central region 27 and the outer peripheral region 25, and the cells 7 (first cell 11 and second cell 15) are straight along the X direction and the Y direction. Are lined up. In such a configuration, when the opening area of the first cell 11 and the opening area of the second cell 15 are not more than the opening area of the first cell 11 in the central region 27 only in the first column from the side surface 21, The thickness of the partition wall 9 surrounding the first row of cells 7 is larger than that of other portions. Therefore, even when a force to crush the honeycomb segment 1e from the side is applied, the partition wall 9 existing in the outer peripheral region 25 is less likely to buckle. That is, according to the honeycomb segment 1e, it is possible to more reliably suppress the breakage of the partition walls 9 in the outer peripheral region 25.

  In addition, in the honeycomb segment 1e, the opening areas of the second cells 15 in the second row and the third row from the side surface 21 are larger than the opening areas of the second cells 15 in the first row from the side surface 21. Therefore, according to the honeycomb segment 1e, as compared with the above-described honeycomb segment 1c, a large amount of particulate matter is collected by the partition walls 9 surrounding the second cells 15 in the second row and the third row, but the pressure loss is reduced. It is possible to suppress the increase.

  In the honeycomb segment 1, the shape of the first cell 11 and the second cell 15 may be such that the opening area of the first cell 11 is smaller than the opening area of the second cell 15. For example, the shapes of the first cell 11 and the second cell 15 can be polygonal shapes such as a triangle, a quadrangle, a hexagon, and an octagon, respectively. In particular, it is preferable that the shape of the second cell 15 is an octagon and the shape of the first cell 11 is a quadrangle (see FIG. 4). In this case, it is more preferable that the length of “four sides adjacent to the first cell 11 across the partition wall 9” of the second cell 15 is the same as the width of the first cell 11 (see FIG. 4). In this way, the mechanical strength of the honeycomb segment 1 can be improved.

  The thickness of the partition walls 9 constituting the honeycomb segment 1 in a cross section perpendicular to the Z direction (hereinafter simply referred to as “thickness of the partition walls 9”) is basically uniform at least in the central region 27. And “Basically uniform” means that the thickness of the partition wall 9 is uniform except when the thickness of the partition wall 9 is slightly different due to deformation during molding or the like. For example, when the slit of the die (die) for extruding the honeycomb segment 1 is manufactured by slicer processing, the partition wall 9 having the uniform thickness is realized.

  The thickness of the partition wall 9 is preferably 64 to 508 μm, more preferably 89 to 483 μm, and particularly preferably 110 to 381 μm. By setting the thickness of the partition wall 9 within the above range, the strength of the honeycomb segment 1 can be maintained, and an increase in the initial pressure loss can be further suppressed. If it is thinner than 64 μm, the strength of the honeycomb segment 1 may be lowered. If it is thicker than 508 μm, the initial pressure loss of the honeycomb segment 1 may increase. The thickness of the partition wall 9 is the thickness of the partition wall 9 in the portion that partitions the first cell 11 and the second cell 15.

  The porosity of the partition walls 9 is preferably 35 to 70%, more preferably 40 to 70%, and particularly preferably 40 to 68%. By setting the porosity of the partition walls 9 within the above range, the strength of the honeycomb segment 1 can be maintained, and an increase in the initial pressure loss can be further suppressed. When the porosity is smaller than 35%, the initial pressure loss of the honeycomb segment 1 may be increased. If the porosity is higher than 70%, the strength of the honeycomb segment 1 may be lowered. The porosity is a value measured by a mercury porosimeter.

  The average pore diameter of the partition walls 9 is preferably 7 to 30 μm, more preferably 8 to 27 μm, and particularly preferably 9 to 25 μm. By setting the average pore diameter of the partition walls 9 within the above range, the strength of the honeycomb segment 1 can be maintained, and an increase in the initial pressure loss can be further suppressed. When the average pore diameter is smaller than 7 μm, the initial pressure loss of the honeycomb segment 1 may be increased. When the average pore diameter is larger than 30 μm, the collection performance of ash and particulate matter may be lowered. The average pore diameter is a value measured with a mercury porosimeter.

Cell density of the honeycomb segment 1 is not particularly limited, preferably from 15 to 62 pieces / cm ^2, more preferably from 31 to 56 pieces / cm ^2. When the cell density is in the above range, the pressure loss can be kept low while maintaining the strength of the honeycomb segment 1. If the cell density is less than 15 cells / cm ² , the strength of the honeycomb segment 1 is lowered, so that there is a possibility of destruction during canning. If the cell density is larger than 62 cells / cm ² , the initial pressure loss becomes too high, and the engine output may be reduced or the fuel consumption may be deteriorated. In this specification, “cell density” means the number of cells 7 per unit area (per 1 cm ² ) in a cross section perpendicular to the Z direction.

  The material of the partition walls 9 is preferably ceramic, and is excellent in strength and heat resistance, so that cordierite, silicon carbide, silicon-silicon carbide based composite material, mullite, alumina, aluminum titanate, silicon nitride, and silicon carbide cordier. More preferred is at least one selected from the group consisting of light composite materials.

  Examples of the material of the plugging portion 19 include the same material as that of the partition wall 9, and the same material as that of the partition wall 9 is preferably used.

  The honeycomb segment 1 preferably has a length L in the Z direction of 50 to 381 mm, more preferably 70 to 330 mm, and particularly preferably 100 to 305 mm. By setting it as the said range, the collection volume according to PM discharge | emission amount from various engines is securable in the range of the limited space.

  The honeycomb segment 1 preferably has a width W (width in the X direction and Y direction) in a cross section perpendicular to the Z direction of 25 to 50 mm, more preferably 30 to 45 mm, and 33 to 43 mm. Particularly preferred. By setting it as the said range, the collection volume according to PM discharge | emission amount from various engines is securable in the range of the limited space.

  The honeycomb segment 1 preferably has a length L / width W value of 1.0 to 12.0, more preferably 1.3 to 8.5, and 1.3 to 7.3. It is particularly preferred that By setting it as the said range, a ring crack can be suppressed.

  The bonding layer 23 is made of a bonding material for bonding and integrating the plurality of honeycomb segments 1.

  The actual thickness of the bonding layer 23 is appropriately determined depending on the shape of the honeycomb segment 1 and the arrangement of the plurality of honeycomb segments 1.

  The bonding layer 23 is preferably disposed from the inflow end surface 3 to the outflow end surface 5 of the honeycomb segment 1.

  Although there is no restriction | limiting in particular about the material of the joining layer 23, For example, the material etc. which couple | bonded ceramic particles, such as a silicon carbide, an alumina, and silicon nitride, by colloidal silica and colloidal alumina can be mentioned as a suitable example. By using such a material, the thermal stress generated in the honeycomb filter 50 can be satisfactorily reduced. Further, by using such a material, the bonding layer 23 also serves as a buffer material when a load is applied to the honeycomb filter 50.

Further, the bonding layer 23 preferably has a thermal expansion coefficient of 2.0 × 10 ⁻⁶ / K or more and 4.0 × 10 ⁻⁶ / K or less. The Young's modulus of the bonding layer 23 is preferably 0.01 GPa or less. The thermal expansion coefficient is the thermal expansion coefficient of the bonding layer 23 from 40 ° C. to 800 ° C.

  The number of honeycomb segments 1 constituting the honeycomb filter 50 is not particularly limited. For example, the honeycomb filter 50 shown in FIG. 1 has a cylindrical appearance, and has 16 honeycomb segments 1. In the honeycomb filter 50, the four honeycomb segments 1 are complete segments, and the complete segments are arranged in a 2 × 2 array in a cross section orthogonal to the Z direction. Further, twelve honeycomb segments 1 located on the outer periphery of the four complete segments (the outer periphery in the cross section orthogonal to the Z direction) are incomplete segments. The shape of the incomplete segment has a shape (for example, an arc portion) corresponding to the outer peripheral shape of the honeycomb filter 50 in a part of the cross-sectional shape orthogonal to the Z direction.

  For example, with respect to the honeycomb filter 50 having a cylindrical appearance shown in FIG. 1, first, 16 complete segments are arranged in 4 × 4 and joined to form a joined honeycomb segment assembly. Make it. Next, the outer periphery of the joined honeycomb segment assembly is ground so as to have a circular cross-sectional shape, and the outer periphery is coated with a coating material (material of the outer peripheral wall 31). At this time, the partially segmented honeycomb segment 1 becomes an incomplete segment.

2. Manufacturing method of honeycomb filter:
Next, a method for manufacturing the honeycomb filter of the present embodiment will be described. First, a kneaded material for preparing a honeycomb segment is prepared, and this kneaded material is formed to prepare a formed body of a plurality of honeycomb segments (forming step). The obtained honeycomb segment formed body is preferably dried to obtain a dried honeycomb segment body.

  Next, the obtained honeycomb segment formed body (or the dried honeycomb segment dried body if necessary) is fired to prepare a honeycomb segment (honeycomb segment manufacturing step).

  Next, the openings of predetermined cells (first cells) on the inflow end face of each of the obtained honeycomb segments and the openings of the remaining cells (second cells) on the outflow end face are plugged. A stop part is formed (plugging process).

  Next, the obtained honeycomb segments are joined with a joining material to produce a joined honeycomb segment (honeycomb filter) (honeycomb segment joining step). That is, a honeycomb segment bonded body (honeycomb filter) in which a plurality of honeycomb segments are arranged adjacent to each other so that the side surfaces thereof face each other and the opposite side surfaces are bonded to each other by the bonding material is manufactured. The number of honeycomb segments to be joined is preferably a number according to the size of the honeycomb filter to be manufactured. The bonding material plays a role of buffering (absorbing) the volume change when the honeycomb segments are thermally expanded and contracted, and also functions of bonding the honeycomb segments. This bonding material becomes a bonding layer in the honeycomb filter of the present embodiment.

  Moreover, after forming a joined body, it is preferable to cut the outer peripheral part of a joined body into a desired shape. When manufacturing the honeycomb filter of the present embodiment, the honeycomb segment located at the outermost periphery is cut so that the shape in the cross section perpendicular to the axial direction is a circle, an ellipse, a racetrack shape, It is preferable to cut the outer peripheral portion of the joined body.

  In this way, the honeycomb filter of the present embodiment can be manufactured. Hereinafter, each manufacturing process will be described in more detail.

2-1. Molding process:
First, in the forming step, a ceramic forming raw material containing a ceramic raw material is formed to form a honeycomb formed body in which a plurality of cells serving as fluid flow paths are formed.

  Ceramic raw materials contained in ceramic forming raw materials include silicon carbide (SiC), silicon-silicon carbide based composite materials, silicon nitride, cordierite forming raw materials, cordierite, mullite, alumina, titania, silicon carbide, aluminum titanate, etc. Can be mentioned. And at least one selected from the group consisting of silicon carbide (SiC), silicon-silicon carbide based composite material, cordierite forming raw material, cordierite, mullite, alumina, titania, silicon carbide, and aluminum titanate. Is preferred. The “silicon-silicon carbide based composite material” is formed using silicon carbide (SiC) as an aggregate and silicon (Si) as a binder. "Cordierite raw material" is a ceramic raw material blended to have a chemical composition that falls within the range of 42 to 56% by mass of silica, 30 to 45% by mass of alumina, and 12 to 16% by mass of magnesia. It is fired to become cordierite.

  The ceramic forming raw material is preferably prepared by mixing the ceramic raw material with a dispersion medium, an organic binder, an inorganic binder, a pore former, a surfactant and the like. The composition ratio of each raw material is not particularly limited, and is preferably a composition ratio in accordance with the structure and material of the honeycomb structure part to be manufactured.

  When forming the ceramic forming raw material, it is preferable to first knead the forming raw material to form a kneaded material, and the obtained kneaded material is formed into a honeycomb shape. 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. A method for forming a kneaded clay to form a honeycomb formed body is not particularly limited, and a conventionally known forming method such as extrusion molding or injection molding can be used. For example, a method of forming a honeycomb formed body by extrusion molding using a die having a desired cell shape, partition wall thickness, and cell density can be cited as a suitable example. As the material of the die, a cemented carbide which does not easily wear is preferable.

  Further, after the above forming, the obtained honeycomb formed body may be dried. The drying method is not particularly limited, and examples thereof include hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying and the like. Among them, dielectric drying, microwave drying or It is preferable to perform hot air drying alone or in combination.

2-2. Honeycomb segment manufacturing process:
Next, the obtained honeycomb formed body is fired to obtain a honeycomb segment. The honeycomb formed body may be fired after disposing the plugging portions on the honeycomb formed body.

  Further, before firing (main firing) the honeycomb formed body, it is preferable to calcine the honeycomb formed body. The calcination is performed for degreasing, and the method thereof is not particularly limited as long as the organic matter (organic binder, dispersion medium, pore former, etc.) therein can be removed. In general, the combustion temperature of the organic binder is about 100 to 300 ° C., and the combustion temperature of the pore former is about 200 to 800 ° C. Therefore, the calcining conditions are about 200 to 1000 ° C. in an oxidizing atmosphere, 3 to It is preferable to heat for about 100 hours.

  Firing of the honeycomb formed body (main firing) is performed in order to sinter and densify the forming raw material constituting the calcined formed body to ensure a predetermined strength. Since the firing conditions (temperature, time, atmosphere) vary depending on the type of molding raw material, appropriate conditions may be selected according to the type. For example, when a cordierite forming raw material is used, the firing temperature is preferably 1410 to 1440 ° C. In addition, the firing time is preferably 4 to 6 hours as a keep time at the maximum temperature.

  When the honeycomb structure portion is composed of a plurality of honeycomb segments, a plurality of honeycomb formed bodies or fired honeycomb formed bodies are bonded together with a bonding material in a state where they are arranged adjacent to each other so that their side faces face each other. To do. A conventionally known bonding material can be used as the bonding material.

2-3. Plugging process:
Next, a plugging material is filled into the end portion on the inflow end face side of the first cell of the honeycomb segment and the end portion on the outflow end face side of the remaining second cell to form a plugging portion.

  When filling the honeycomb segment with the plugging material, for example, the end portion on the inflow end face side is first filled with the plugging material, and then the end portion on the outflow end face side is filled with the plugging material. Examples of the method of filling the end portion with the plugging material include a method having the following masking process and press-fitting process. The masking step is a step of attaching a sheet to one end surface (for example, the inflow end surface) of the honeycomb segment, and forming a hole at a position overlapping with the “cell in which the plugging portion is to be formed” in the sheet. In the press-fitting process, “the end of the honeycomb structure portion on the side where the sheet is attached” is press-fitted into a container in which the plugging material is stored, and the plugging material is pressed into the cells of the honeycomb segment. It is a process. When the plugging material is pressed into the cells of the honeycomb segment, the plugging material passes through the holes formed in the sheet and is filled only in the cells communicating with the holes formed in the sheet.

  Next, the plugging material filled in the honeycomb segment is dried to form a plugged portion to obtain a plugged honeycomb segment. The plugging material may be dried after filling both ends of the honeycomb segment, or after the plugging material filled in one end of the honeycomb segment is dried, the other The plugging material may be filled in one end of the plug, and then the plugging material filled in the other end may be dried. Furthermore, the plugging material may be fired for the purpose of more reliably fixing. Further, the plugging material may be filled in the honeycomb formed body before drying or the dried honeycomb formed body, and the plugging material may be fired together with the honeycomb formed body before drying or the honeycomb formed body after drying.

2-4. Honeycomb segment joining process:
Next, the obtained honeycomb segments are bonded with a bonding material, and a plurality of honeycomb segments are arranged adjacent to each other so that the side surfaces face each other, and the opposite side surfaces are bonded by a bonding layer. A bonded honeycomb segment assembly is produced.

  The honeycomb segments are preferably bonded using a bonding material. 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.

  A bonding material for bonding the side surfaces of the honeycomb segments becomes a bonding layer in the manufactured honeycomb filter.

  After bonding a plurality of honeycomb segments with a bonding material, it is preferable to cut the outer peripheral portion of the obtained bonded honeycomb segment assembly into a desired shape. In addition, it is preferable to manufacture the honeycomb filter by bonding the honeycomb segments and cutting the outer peripheral portion of the joined body of the honeycomb segments and then disposing the outer peripheral coating material on the outer peripheral portion. This outer peripheral coating material becomes the outer peripheral wall of the honeycomb filter. By providing such an outer peripheral wall, there is an advantage that the roundness of the honeycomb filter is improved.

  With such a configuration, the honeycomb filter of the present embodiment can be manufactured. However, the manufacturing method of the honeycomb filter of the present embodiment is not limited to the manufacturing method described above.

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

Example 1
As a ceramic raw material, a mixture of silicon carbide (SiC) powder and metal silicon (Si) powder in a mass ratio of 80:20 was used. Then, hydroxypropylmethylcellulose as a binder and a water-absorbing resin as a pore former were added thereto, and water was added to prepare a molding raw material. The obtained forming raw material was kneaded using a kneader to obtain clay.

  Next, the obtained kneaded material was molded using a vacuum extrusion molding machine to produce a plurality of honeycomb segment molded bodies in which a plurality of cells were partitioned by partition walls.

  Next, the obtained honeycomb segment formed body was dried by high-frequency dielectric heating, and then dried at 120 ° C. for 2 hours using a hot air dryer. In addition, at the time of drying, it arrange | positioned so that the outflow end surface of the molded object of a honeycomb segment might face vertically downward, and it dried.

  A plugged portion was formed on the dried honeycomb segment formed body. First, a mask was applied to the opening of the cell on the inflow end face side of the honeycomb segment formed body. At this time, cells whose openings were completely covered with a mask and cells whose openings were not completely covered with a mask were alternately arranged. Then, the end of the honeycomb segment formed body on which the mask was applied was immersed in a plugging slurry (plugging material), and the openings of the cells not provided with the mask were filled with the plugging slurry. . Then, the plugged portions were formed in the same manner for the remaining cells on the outflow end surface of the formed honeycomb segment body after drying (that is, the cells where the plugged portions were not formed on the inflow end surface).

  Then, the honeycomb segment formed body in which the plugged portions were formed was degreased and fired to obtain a honeycomb segment in which the plugged portions were arranged in the openings of the cells. The degreasing conditions were 550 ° C. for 3 hours. The firing conditions were 1450 ° C. and 2 hours in an argon atmosphere. At the time of firing, firing was performed by arranging the outflow end surface of the honeycomb segment formed body vertically downward.

The obtained honeycomb segment had a partition wall thickness of 317.5 μm in the center region and a cell density of 46.5 cells / cm ² . The honeycomb segment had a quadrangular prism shape (41.5 mm × 41.5 mm square cross-sectional shape). In the second and subsequent columns from the side, the cross-sectional shape of the first cell is a square, and the cross-sectional shape of the second cell is an octagon (between the long side and the long side of the four sides extending in the X direction and the Y direction). It was an octagon surrounded by an intervening short side) (see FIG. 4). The ratio of the opening area of the second cell to the opening area of the first cell in the central region was 1.7. Further, regarding the honeycomb segment of Example 1, the ratio of the opening area of the second cell and the opening area of the first cell in the outer peripheral region (of the “processing cell range”) (opening area of the second cell / opening of the first cell) (Area ratio) ”,“ value B _C ”,“ value B _O ”,“ value of the difference between the distance A ₁ and the distance A ₂ among the cell columns from the side surface to the third column is shown in Table 1. Table 1 shows the number of columns to be B 2 _O (processing cell range).

  Sixteen honeycomb segments described above were produced. Then, the 16 honeycomb segments were arranged in a 4 × 4 array, joined with a joining material, and the joining material was dried to obtain a joined body of honeycomb segments. The dried bonding material becomes a bonding layer. When the bonding material was applied to the side surface of the honeycomb segment, the thickness of the bonding layer was set to 1.0 mm.

  Next, the outer periphery of the joined body of honeycomb segments was ground so that the overall shape thereof was a cylindrical shape. Thereafter, a ceramic material was applied to the outer periphery of the bonded honeycomb segment assembly to form an outer peripheral wall, thereby obtaining a honeycomb filter. The shape of the cross section perpendicular to the Z direction of the honeycomb filter was a circle having a diameter of 165.0 mm. The length of the honeycomb filter in the Z direction was 140.5 mm.

(Examples 2 to 6)
The honeycomb filters of Examples 2 to 6 were manufactured in the same manner as Example 1 except that the conditions were changed as shown in Table 1.

(Comparative Example 1)
The value B _C and the value B _O are both 0.17 mm, the cross-sectional shape of the first cell is square, the cross-sectional shape of the second cell is octagonal (the long sides of the four sides extending in the X direction and the Y direction are (An octagon surrounded by a short side interposed therebetween) (see FIG. 4), the ratio of the opening area of the second cell to the opening area of the first cell in the entire region (opening area of the second cell / opening of the first cell) A honeycomb filter was obtained by the same method as in Example 1 except that the area ratio was 1.7 and the value _BC and the value _BO were made equal.

  The honeycomb filters of Examples 1 to 6 and Comparative Example 1 were evaluated for [isostatic strength] and [pressure loss]. The evaluation method for each evaluation is shown below.

[Isostatic strength]
The measurement of isostatic strength was performed based on the isostatic fracture strength test prescribed | regulated by M505-87 of the automobile standard (JASO standard) by the Japan Society for Automotive Engineers. The isostatic fracture strength test is a test in which a honeycomb filter is placed in a rubber cylindrical container, covered with a rubber plate, and isotropically compressed in water. In other words, the isostatic fracture strength test is a test that simulates the compression load applied when the honeycomb filter is gripped on the outer peripheral surface of the can body. The isostatic strength measured by this isostatic fracture strength test is indicated by a pressure value (MPa) when the honeycomb filter breaks. For Examples 1 to 6, Table 1 shows the increase / decrease (%) (for example, + 10% in the case of 110%) when the isostatic strength of the honeycomb filter of Comparative Example 1 is used as the reference (100%).

[Measurement of pressure loss (kPa)]:
For the pressure loss, the pressure loss when air was supplied was measured. In measuring the pressure loss, first, the manufactured honeycomb filter was stored in a storage can to obtain an exhaust gas purification system. Next, air was supplied to the exhaust gas purification system at a predetermined flow rate. The pressure loss in this case was measured.

Regarding the pressure loss of Examples 1 to 6, increase / decrease (%) (for example, 110%) when the pressure loss of Comparative Example 1 when the air flow rate is “10 Nm ³ / min” is used as the reference (100%) In the case of + 10%), the results are shown in Table 1.

[Discussion]
Compared with the honeycomb filter of Comparative Example 1, the honeycomb filters of Examples 1 to 6 had an increased isostatic strength and were able to suppress an increase in pressure loss to 16% or less.

  The present invention can be used as a filter for purifying exhaust gas discharged from an internal combustion engine such as a diesel engine or various combustion apparatuses.

1, 1a to 1e: honeycomb segment, 3: inflow end surface, 5: outflow end surface, 7: cell, 9: partition wall, 11: first cell, 13: opening of (first cell), 15: second cell, 17: (second cell) opening, 19: plugging portion, 21: side surface, 23: bonding layer, 25: outer peripheral region, 27: central region, 31: outer peripheral wall, 33: side wall, 35: intersection portion 50: Honeycomb filter.

Claims (7)

A plurality of honeycomb segments having partition walls that define a plurality of cells that serve as fluid flow paths extending from the inflow end surface to the outflow end surface;
The opening on the inflow end face side of the first cell that is a predetermined cell among the plurality of cells formed in the honeycomb segment and the outflow end face of the second cell that is the remaining cell among the plurality of cells. A plurality of plugged portions for sealing the opening on the side;
A bonding layer for bonding at least a part of the side surfaces of the plurality of honeycomb segments,
In the honeycomb segment, the first cell and the second cell are alternately arranged, and the outer peripheral region and the side surface forming the cells arranged in the first to third rows from the side surface of the honeycomb segment. And a central region forming the cells arranged in the fourth and subsequent columns,
In the central region, in the cross section perpendicular to the cell extending direction, the opening area of the first cell is smaller than the opening area of the second cell,
In the outer peripheral region, in the cross section perpendicular to the cell extending direction, the opening area of the first cell is equal to or smaller than the opening area of the second cell,
In the peripheral region, wherein among the partition walls where the distance from the farthest part to the side from the side surface of the honeycomb segment of the first cell to partition the partition wall and the distance A _1, partitioning the second cell the distance from the farthest portion from the side face of the honeycomb segment to the side and the distance a _2, in the central region, the side from the farthest portion from the side surface of the honeycomb segments among the barrier ribs partitioning the first cell when the distance to the distance a _3, the distance to the side surface and the distance a ₄ from the farthest portion from the side surface of the honeycomb segments among the barrier ribs partitioning the second cell, the same row as counted from the side the difference between the distance a ₂ values B _O of the difference between the distance a ₁ is, and the distance a ₄ and the distance a ₃ in the same row as counted from the side in Small honeycomb filter than the value _{B C.} The honeycomb filter according to claim 1 wherein the value B _O is zero.   The honeycomb filter according to claim 1 or 2, wherein, in the outer peripheral region, the opening area of the first cell is equal to the opening area of the second cell.   The opening area of the first cell and the opening area of the second cell in the outer peripheral region are equal to or less than the opening area of the first cell in the central region. Honeycomb filter. In only the first column from the side, the honeycomb filter according to claim 1 wherein the value B _O is zero.   The honeycomb filter according to claim 1 or 5, wherein the opening area of the first cell is equal to the opening area of the second cell only in the first row from the side surface.   The opening area of the first cell and the opening area of the second cell are not more than the opening area of the first cell in the central region only in the first row from the side surface. The honeycomb filter according to any one of 6.

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