JP2019130459A - Honeycomb structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a honeycomb structure capable of improving the strength of a structure while suppressing an increase in pressure loss. A honeycomb structure 1 has a base region 11 and an outer peripheral reinforcing region 12. The outer peripheral strengthening region 12 is a cell forming a direction perpendicular to the side L of the virtual regular hexagon H when the virtual regular hexagon H whose B axis is tilted by 30 degrees with respect to the center cell 20 is drawn coaxially with the center cell 20. It has a plurality of non-regular hexagonal flat cells 21 formed by using a pair of short cell walls 30 in which the length of the wall 3 is shorter than the length of the cell wall in the base region 11. The plurality of flat cells 21 are arranged side by side along the sides of the virtual regular hexagon H. The cell pitch of the flat cell 21 is equivalent to the cell pitch of the cell 2 in the base region 11, and the length h1 of the short cell wall 3 of each flat cell 21 arranged in the same row in the direction along the side L of the virtual regular hexagon H is different. It is considered to be equivalent. [Selection diagram] Fig. 1

Description

  The present invention relates to a honeycomb structure, and more particularly to a honeycomb structure having cells having a hexagonal cross section.

  Conventionally, in the field of vehicles such as automobiles, exhaust gas purification apparatuses are used to purify exhaust gas discharged from an internal combustion engine. The exhaust gas purification apparatus includes a ceramic honeycomb structure housed in an exhaust pipe and a catalyst component held in the honeycomb structure. A honeycomb structure usually includes a plurality of cells adjacent to each other, a plurality of cell walls that form a plurality of cells, and an outer peripheral wall that is provided on the outer periphery of the plurality of cell walls and holds the cell walls. Yes. The catalyst component is held on the cell wall surface.

  In the prior Patent Document 1, in a honeycomb structure having an elliptical outer peripheral wall, 30 ° <θ <45 °, where θ is an angle formed between the B axis and the C axis of a hexagonal cross section cell. A honeycomb structure having an isostatic strength of 4 MPa or more is described.

JP 2004-181458 A

  In recent years, exhaust gas purification devices are required to have early warm-up and low pressure loss due to stricter exhaust gas regulations and fuel efficiency regulations. Accordingly, in the honeycomb structure, the wall thickness of the cell wall has been reduced year by year. However, reducing the wall thickness reduces the structure strength of the honeycomb structure. Therefore, in the canning process in which the honeycomb structure holding the catalyst component is accommodated in the exhaust pipe, the honeycomb structure is likely to be broken by the compressive stress applied from the radial direction. In particular, a honeycomb structure having cells having a hexagonal cross section has a lower structure strength than a honeycomb structure having cells having a quadrangular cross section, and is easily broken by stress concentration during canning.

  On the other hand, in the above-described conventional honeycomb structure, in order to improve the structure strength, the regular hexagonal cells are not deformed as much as possible (by cell deformation until deformation in the range of 30 ° <θ <45 °). Try to secure strength). However, according to this technique, it is difficult to limit the regular hexagonal cells to partial deformation, and it is necessary to deform all the cells constituting the honeycomb structure. Therefore, in the conventional honeycomb structure, the pressure loss becomes large. Further, in the conventional honeycomb structure, the outer peripheral wall of the honeycomb structure has an elliptical shape, so that the pressure loss tends to increase from this point.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a honeycomb structure capable of improving the structure strength while suppressing an increase in pressure loss.

One aspect of the present invention is a plurality of cells (2) having a hexagonal cross section adjacent to each other, a plurality of cell walls (3) forming the plurality of cells, and the outer periphery of the plurality of cell walls. A honeycomb structure (1) having an outer peripheral wall (4) for holding a cell wall,
In a cross-sectional view perpendicular to the honeycomb central axis (10),
A base region having a regular hexagonal center cell (20) configured to include a plurality of regular hexagonal cells, the honeycomb central axis passing through the cell center;
A plurality of the non-regular hexagonal shaped cells, the outer peripheral reinforcing region (12) disposed on the outer periphery of the base region,
When the virtual regular hexagon (H) whose B-axis is inclined by 30 degrees with respect to the central cell is drawn coaxially with the central cell, the outer periphery reinforcing region is perpendicular to the side (L) of the virtual regular hexagon. A non-regular hexagonal flat cell (21) formed using a pair of short cell walls (30) in which the length of the cell wall constituting the cell is shorter than the length of the cell wall in the base region Have multiple
The plurality of flat cells are arranged side by side in a direction along the side of the virtual regular hexagon,
When viewed in the direction along the side of the virtual regular hexagon, the cell pitch of the flat cell is equivalent to the cell pitch of the cell in the base region,
In the honeycomb structure (1), the lengths of the short cell walls of the flat cells arranged in the same row in the direction along the side of the virtual regular hexagon are equal to each other.

  The honeycomb structure has the above-described configuration. In other words, unlike the conventional honeycomb structure, the above honeycomb structure is actively deformed in a certain direction using flat cells that satisfy the above configuration only in the outer periphery strengthening region where stress concentration is likely to occur during canning. The regular hexagonal cells in the base region are basically not deformed. Therefore, according to the honeycomb structure, an increase in pressure loss can be suppressed. Moreover, the structure strength of the honeycomb structure can be improved by arranging the flat cells having short cell walls having high buckling strength in the outer peripheral reinforcing region.

  In addition, the code | symbol in the parenthesis described in the means to solve a claim and a subject shows the correspondence with the specific means as described in embodiment mentioned later, and limits the technical scope of this invention. It is not a thing.

FIG. 3 is an explanatory diagram showing a simplified cross-sectional structure perpendicular to the honeycomb central axis of the honeycomb structure of the first embodiment. FIG. 2 schematically shows cells included in the honeycomb structure of Embodiment 1, wherein (a) is a flat cell included in the outer peripheral reinforcing region, (b) is a deformed cell that can be included in the outer peripheral reinforcing region, (c) ) Is a normal cell in the base region. It is explanatory drawing for demonstrating how to count the number of the reinforcement | strength row | line | columns in a periphery reinforcement area | region. It is explanatory drawing which showed the same row | line | column in an outer periphery reinforcement area | region. FIG. 6 is an explanatory diagram showing a simplified cross-sectional structure perpendicular to the honeycomb central axis of the honeycomb structure of the second embodiment. FIG. 6 is an explanatory view showing a part of the outer peripheral reinforcing region in the honeycomb structure of Embodiment 3 in a simplified manner. FIG. 6 is an explanatory diagram showing a simplified cross-sectional structure perpendicular to the honeycomb central axis of a honeycomb structure according to a fourth embodiment. 6 schematically shows cells included in the honeycomb structure of the fifth embodiment, in which (a) has a reinforcing portion included in the base region, and (b) has a reinforcing portion included in the outer peripheral reinforcing region. FIG. It is a flat cell. FIG. 10 is an explanatory diagram showing a simplified cross-sectional structure perpendicular to the honeycomb central axis of a honeycomb structure according to a sixth embodiment. FIG. 10 is an explanatory diagram schematically showing an enlarged portion A of FIG. 9 in order to explain the three-pronged unit. FIG. 3 is an explanatory diagram showing, in a simplified manner, a cross-sectional structure perpendicular to the honeycomb central axis of a honeycomb structure of a test body 1C in Experimental Example 1. It is explanatory drawing for demonstrating the evaluation method of the pressure loss in Experimental example 1. FIG.

(Embodiment 1)
The honeycomb structure of the first embodiment will be described with reference to FIGS. As illustrated in FIGS. 1 to 4, the honeycomb structure 1 of the present embodiment is made of ceramics (for example, cordierite or the like), and has a plurality of cells 2 each having a hexagonal cross section adjacent to each other, and a plurality of cells. 2, and a plurality of cell walls 3 that form 2, and an outer peripheral wall 4 that is provided on the outer periphery of the plurality of cell walls 3 to hold the cell wall 3. 1, 3, and 4, the cell wall 3 is represented by a line for convenience, and the wall thickness and the like of the cell wall 3 are omitted.

  In the present embodiment, the cell 2 includes a through hole extending along the honeycomb central axis 10 that is an axis passing through the center of the honeycomb structure 1. The cell 2 is a part that is a flow path through which the exhaust gas to be purified flows. The cross section referred to in the above hexagonal cross section means a cross section perpendicular to the honeycomb central axis 10. Further, the hexagonal shape referred to in the above-mentioned hexagonal cross section includes a regular hexagon, a non-regular hexagon, a hexagon with rounded corners, a hexagon that is distorted unintentionally in production, and the like. The plurality of cell walls 3 are connected and integrated with the adjacent cell walls 3. On the wall surface of the cell wall 3 on the cell 2 side, a catalyst component is supported when the honeycomb structure 1 is used. The outer peripheral wall 4 has a circular shape in a cross-sectional view perpendicular to the honeycomb central axis 10. A plurality of cell walls 3 arranged near the inner side surface of the outer peripheral wall 4 are connected to the inner side surface of the outer peripheral wall 4. Thus, the plurality of cell walls 3 are integrally held by the outer peripheral wall 4.

  As illustrated in FIG. 1, the honeycomb structure 1 includes a base region 11 and an outer peripheral reinforcing region 12 in a cross-sectional view perpendicular to the honeycomb central axis 10.

The base region 11 includes a plurality of regular hexagonal cells 2 and is a region having a regular hexagonal center cell 20 in which the honeycomb central axis 10 passes through the cell center. Specifically, in the base region 11, the cell walls 3 included in the base region 11 can have the same wall thickness. More specifically, when the average value of the wall thickness of each cell wall 3 constituting the central cell 20 and the six cells 2 surrounding the central cell 20 is t _ave , the cell walls included in the base region 11 The wall thickness t of 3 can be in the range of 0.97 × t _{ave to} 1.03 × t _ave . When the wall thickness of the cell wall 3 included in the base region 11 is within the above range, it can be said that the wall thickness is equivalent because it can be said to be within the error range with respect to t _ave .

  The outer periphery strengthening region 12 is configured to include a plurality of non-regular hexagonal cells 2 and is disposed on the outer periphery of the base region 11. Specifically, the outer peripheral reinforcement region 12 is integrally connected to the base region 11. FIG. 1 shows an example in which the outer periphery strengthening region 12 is configured to continuously cover the base region 11 in the circumferential direction.

  The outer periphery strengthening region 12 has a plurality of non-regular hexagonal flat cells 21. Hereinafter, the flat cell 21 will be described.

  As illustrated in FIG. 1, a virtual regular hexagon H whose B axis is inclined by 30 degrees with respect to the center cell 20 is drawn coaxially with the center cell 20. As shown in FIG. 2 (c), in a cross-sectional view perpendicular to the honeycomb central axis, a pair of opposing cell apexes of regular hexagonal cells 2 are connected, and the cells 2 are symmetrical about the axis. The axis that becomes the shape is the C axis. The axis perpendicular to the C axis and passing through the center of the cell 2 is the B axis. In FIG. 1, the virtual regular hexagon H is drawn so that each vertex exists inside the outer peripheral wall 4.

  In the outer periphery strengthening region 12, the flat cell 21 is configured such that the length of the cell wall 3 constituting the direction perpendicular to the side L of the virtual regular hexagon H is the base region 11 as illustrated in FIGS. Are formed using a pair of short cell walls 30 that are shorter than the length of the cell wall 3 in FIG. This will be described more specifically.

  As illustrated in FIG. 1, six first virtual straight lines V1 each connecting the honeycomb central axis 10 and each vertex of the virtual regular hexagon H are drawn as auxiliary lines. Then, the description will be given mainly focusing on the 1/6 portion of the honeycomb structure 1 between the adjacent first virtual straight lines V1. As shown in FIGS. 1 and 2, the length of the cell wall 3 constituting the direction perpendicular to the side L of the virtual regular hexagon H in the outer periphery strengthening region 12 is h1. In the base region 11, the length of the cell wall 3 constituting the direction perpendicular to the side L of the virtual regular hexagon H is h. At this time, h1 and h satisfy the relationship of h1 <h. That is, as illustrated in FIGS. 1 and 2C, the cell 2 in the base region 10 includes a pair of cell walls 3 having a length h that forms a direction perpendicular to the side L of the virtual regular hexagon H, It consists of four cell walls 3 of length h. On the other hand, the flat cell 30 in the outer periphery reinforcement area | region 12 is the short cell wall 30 as a pair of cell wall 3 whose length is h1, and the four cell walls 3 from which the short cell wall 30 differs in length. It is configured. In addition, a pair of short cell wall 30 is arrange | positioned so that it may oppose. As described above, the flat cell 30 in the outer periphery strengthening region 12 is distorted in the direction perpendicular to the side L of the virtual regular hexagon H by shortening the cell wall 3 constituting the direction perpendicular to the side L of the virtual regular hexagon H. It has a non-regular hexagonal shape.

  In the outer periphery strengthening region 12, the plurality of flat cells 21 are arranged side by side in the direction along the side L of the virtual regular hexagon H as shown in FIGS. 1 and 4. Whether or not the outer peripheral reinforcement region 12 is configured from the region up to any number of rows counting from the outer peripheral wall 4 side, that is, the number of reinforcement columns in the outer peripheral reinforcement region 12 is obtained as follows. be able to.

  In addition to the six first virtual straight lines V1 described above, FIG. 1 further shows six second virtual straight lines connecting the honeycomb central axis 10 and the midpoints between the vertices of the virtual regular hexagon H, respectively. V2 is drawn. Here, the direction of a certain second virtual straight line V2 is defined as the 0 degree direction (in FIG. 1, the second virtual straight line V2 located at the 12 o'clock position is defined as the 0 degree direction). At this time, the directions of the second virtual straight lines V2 at the positions of 60 degrees, 120 degrees, 180 degrees, 240 degrees, and 300 degrees clockwise from there are respectively the 60 degree direction, 120 degree direction, 180 degree direction, The direction is 240 degrees and 300 degrees. The direction of each first virtual straight line V1 located at 30 degrees, 90 degrees, 150 degrees, 210 degrees, 270 degrees, and 330 degrees clockwise from the second virtual line V2 in the 0 degree direction is 30 degrees, respectively. Direction, 90 degree direction, 150 degree direction, 210 degree direction, 270 degree direction, and 330 degree direction.

  As shown in FIG. 3, the short cell walls 30 parallel to the respective second imaginary straight lines in the direction of 60 ° × n (where n = 0, 1, 2, 3, 4, 5) in the outer peripheral strengthening region 12. In addition, the first, second,... Then, the short cell wall 30 does not appear inside the honeycomb from the mth from the outer peripheral wall 4. That is, the flat cell 21 does not appear inside the honeycomb from the mth from the outer peripheral wall 4. At this time, the outer periphery strengthening area | region 12 is comprised from the area | region to the m-th line counted from the outer peripheral wall 4 side. In other words, in this case, the number of reinforcement rows by the flat cells 21 in the outer peripheral reinforcement region 12 is m rows. And between adjacent 1st virtual straight lines V1, several flat cells 21 are arrange | positioned along with the direction along the edge | side L of the virtual regular hexagon H about each of each reinforcement row | line | column. Note that, in each flat cell 21 constituting the final reinforcement row counted from the outer peripheral wall 4 side, a regular hexagon formed by connecting the cell apex portions 31 closest to the honeycomb center side is formed by the outer peripheral reinforcement region 12 and the base region 10. And the boundary. In the present embodiment, the above-described virtual regular hexagon H is matched with the size forming the boundary between the outer periphery strengthening region 12 and the base region 10. For this reason, the virtual regular hexagon H forms a boundary between the outer periphery strengthening region 12 and the base region 10.

When viewed in the direction along the side L of the virtual regular hexagon H in the outer periphery strengthened region 12, the cell pitch p <b> 1 of the flat cell 21 is as shown in FIGS. 2A, 2 </ b> C, and 4. It is equivalent to the cell pitch p of the cell 2 (p1≈p). The cell pitch p of the cell 2 in the base region 11 can be calculated as follows. A cell pitch is determined for each cell constituting the center cell 20 and the six cells 2 surrounding the center cell 20. The obtained average value p _{ave of} each cell pitch is set as the cell pitch p of the cell 2 in the base region 11. On the other hand, the cell pitch p1 of the flat cell 21 is determined for each flat cell 21 arranged in the final reinforcement row. The obtained average value p1 _{ave of} each cell pitch is set as the cell pitch p1 of the flat cell 21 in the outer periphery strengthening region 12. When the cell pitch p1 of the flat cell 21 is within the range of 0.97 × p to 1.03 × p, it can be said that it is within the error range with respect to the cell pitch p of the cell 2 in the base region 11, and p and p1 Can be said to be equivalent.

In the outer periphery strengthening region 12, the lengths h1 of the short cell walls 30 of the flat cells 21 arranged in the same row in the direction along the side L of the virtual regular hexagon H are equal to each other. Here, when the average value of the lengths h1 of the short cell walls 30 of the flat cells 21 in the same row is h1 _ave , the length h1 of the short cell walls 30 of the flat cells 21 in the same row is 0. When it is in the range of 97 × h1 _{ave to} 1.03 × h1 _ave , it can be said that it is an error range with respect to h1 _ave , and therefore it can be said that the dimensions are equivalent to each other. In confirming that the relationship of h1 <h described above is satisfied, an average value of the lengths of the short cell walls 30 of the respective flat cells 21 in the final reinforcement row is applied to h1, and h is applied. The average value of the lengths of the cell walls 3 facing the same direction as h1 to be compared in each cell constituting the center cell 20 and the six cells 2 surrounding the center cell 20 may be applied.

Specifically, the wall thickness of the cell wall 3 in the outer peripheral reinforcing region 12 may be such that all the cell walls 3 in the outer peripheral reinforcing region 12 have the same wall thickness, or cell walls 3 having different wall thicknesses. It can also be configured to include The present embodiment is an example in which all the cell walls 3 in the outer periphery strengthening region 12 have the same wall thickness. When the average value of the wall thicknesses of all the cell walls 3 in the outer peripheral strengthening region 12 is t1 _ave , the wall thickness t1 of the cell walls 3 is in the range of 0.97 × t1 _{ave to} 1.03 × t1 _ave. Since it can be said that it is within the error range with respect to t1 _ave , it can be said that the dimensions are equivalent to each other. The present embodiment is an example in which the wall thickness of the cell wall 3 in the outer peripheral reinforcing region 12 is not thicker than the wall thickness of the cell wall 3 in the base region 12. That is, this embodiment can be said to be an example in which the outer periphery strengthening region 12 is mainly strengthened by the shape of the flat cell 21.

  In the honeycomb structure 1, the outer peripheral reinforcing region 12 is preferably composed of a region up to at least a fourth row counted from the outer peripheral wall 4 side. That is, it is preferable that the outer periphery reinforcement area | region 12 has the flat cell 21 to any row | line | column which is at least the 4th row | line or more counting from the outer peripheral wall 4 side. This is because the stress generated during canning takes a high value in the region from the outer peripheral wall 4 to the fourth row portion. Therefore, according to the above configuration, it is possible to improve the strength of the structure with the minimum necessary configuration. In addition, in FIG. 1, the example in which the outer periphery reinforcement area | region 12 is comprised from the area | region to the 4th row counting from the outer peripheral wall 4 side is shown.

  In the honeycomb structure 1, the outer peripheral reinforcing region 12 is preferably composed of a region up to any one row within the 20th row at most from the outer peripheral wall 4 side. Even if the outer peripheral reinforcing region 12 is configured from a region larger than the 20th row, a great improvement in the strength of the honeycomb structure 1 cannot be expected. Further, the number of cells of the honeycomb structure 1 increases toward the outer peripheral portion. Therefore, when the amount of the flat cells 21 in the outer peripheral portion increases, the pressure loss of the honeycomb structure 1 tends to increase. Therefore, by adopting the above-described configuration, the honeycomb structure 1 that can easily improve the structure strength while suppressing an increase in pressure loss can be obtained.

  From the standpoint of ensuring the above effect, the outer periphery strengthening region 12 is more preferably composed of a region up to any one of the 12th row at most from the outer peripheral wall 4 side. it can.

In addition, the cell density in the honeycomb structure 1 can be set to, for example, 46.5 cells / cm ^{2 to} 155 cells / cm ² (300 cpsi to 1000 cpsi).

  In the honeycomb structure 1, the outer periphery reinforcing region 12 can include a deformed cell 22 in addition to the flat cell 21 described above, as shown in FIG. 2 (b) and FIG. 1. In the outer periphery strengthening region 12, the deformed cell 22 is generated in the first virtual straight line V <b> 1 direction that can be generated by using the flat cell 21 in which the regular hexagonal cell 2 in the base region 11 is distorted in one direction as the outer periphery strengthening region 12. It absorbs the cell deformation of the portion of the outer periphery strengthening region 12 and has a role of arranging a plurality of flat cells 21 well in the same row direction. In addition, the deformed cell 22 also has a role of continuously connecting the same columns of the flat cells 21 along two adjacent sides L of the virtual hexagon H. Specifically, the deformation cell 22 is a virtual regular hexagon extending from each vertex of the virtual regular hexagon H on six first virtual straight lines V1 respectively connecting the honeycomb central axis 10 and each vertex of the virtual regular hexagon H. Using the first cell wall 341 constituting a direction perpendicular to one of the two sides L of the square H and the second cell wall 342 constituting a direction perpendicular to the other of the two sides L Is formed. Hereinafter, the deformation cell 22 will be described.

  As shown in FIG. 1, when a regular hexagonal apex that forms a boundary between the base region 11 and the outer peripheral reinforcement region 12 exists inside the outer peripheral wall 4 (within the honeycomb diameter of the honeycomb structure 1), the deformation cell 22 Appears on each of the six first virtual straight lines V1. FIG. 1 shows an example in which two deformed cells 22 having different sizes and shapes are arranged side by side on each first virtual straight line V1. Of the two deformation cells 22, the deformation cell 22 on the base region 11 side has a hexagonal shape (non-regular hexagonal shape). Of the two deformation cells 22, the deformation cell 22 on the outer peripheral wall 4 side has a pentagonal shape (non-regular pentagonal shape).

  As shown in FIGS. 1 and 2B, in the deformed cell 22, the length h2 of the first cell wall 341 and the second cell wall 342 of the deformed cell 22 is perpendicular to each side L of the virtual regular hexagon H. The length is shorter than the length h of the cell wall 3 of the base region 11 constituting a certain direction (h2 <h). Further, the length h2 of the first cell wall 341 and the second cell wall 342 of the deformed cell 22 is the length of the short cell wall 30 of the flat cells 21 arranged in the same row in the direction along the side L of the virtual regular hexagon H. It is equivalent to h1 (h1≈h2 when viewed in the same column). Here, as h1, an average value of the lengths of the short cell walls 30 of the flat cells 21 in the same row is used. Further, as h2, in the direction of 30 degrees × n (where n = 1, 3, 5, 7, 9, 11), the first cell wall 341 of each deformation cell 22 in the same row as the flat cell 21 and An average value of the lengths of the second cell walls 342 is used. Then, h1 and h2 are compared, and when h2 is within the range of 0.97 × h1 to 1.03 × h1, it can be said that it is within the error range with respect to h1, and therefore is equivalent to each other. Can do.

  When the outer peripheral reinforcing region 12 of the honeycomb structure 1 has the deformed cells 22, it is possible to spread flat cells 21 with increased buckling strength from the outer peripheral wall 4 to the inner peripheral portion. Further, the deformed cells 22 continuously connect the rows of the flat cells 21 along the two adjacent sides L of the virtual hexagon H described above. Therefore, in the above case, the structure strength of the honeycomb structure 1 can be ensured.

  The honeycomb structure 1 has the above configuration. That is, the honeycomb structure 1 is different from the conventional honeycomb structure in that the cells 2 are positively fixed by using the flat cells 21 satisfying the above configuration only in the outer peripheral strengthening region 12 where stress concentration is likely to occur during canning. The regular hexagonal cells 2 in the base region 11 are basically not deformed. Therefore, according to the honeycomb structure 1, an increase in pressure loss can be suppressed. Moreover, the structure strength of the honeycomb structure 1 can be improved by arranging the flat cells 21 having the short cell walls 30 having a high buckling strength in the outer peripheral reinforcing region 12.

(Embodiment 2)
The honeycomb structure of the second embodiment will be described with reference to FIG. Of the reference numerals used in the second and subsequent embodiments, the same reference numerals as those used in the above-described embodiments represent the same components as those in the above-described embodiments unless otherwise indicated.

  As shown in FIG. 5, that is, when a regular hexagon forming the boundary between the base region 11 and the outer periphery reinforcing region 12 is drawn, the vertex of the hexagon is outside the outer peripheral wall 4 (outside the honeycomb diameter of the honeycomb structure 1). ). In FIG. 5, the virtual regular hexagon H is drawn as a regular hexagon that forms a boundary between the base region 11 and the outer periphery reinforcing region 12. In this case, among the cells 2 in the base region 11, the cell 2 that is located on the outermost side in the honeycomb radial direction along the first virtual straight line V <b> 1 is connected to the outer peripheral wall 4. That is, unlike the honeycomb structure 1 of the first embodiment, the deformed cells 22 do not appear on the first virtual straight line V1 in the honeycomb structure 1 of the present embodiment. And the outer periphery reinforcement | strengthening area | region 12 has covered the outer periphery of the base area | region discontinuously in the circumferential direction. Other configurations are the same as those of the first embodiment.

  Even in the case of such a configuration, the same operational effects as those of the first embodiment can be basically obtained. However, in the honeycomb structure 1 of the first embodiment, the outer peripheral reinforcing region 12 can be configured by arranging the flat cells 21 further inside.

(Embodiment 3)
The honeycomb structure of Embodiment 3 will be described with reference to FIG.

  As shown in FIG. 6, in the honeycomb structure 1 of the present embodiment, the lengths of the short cell walls 30 in the plurality of flat cells 21 in the outer peripheral reinforcement region 12 are shorter as they are closer to the outer peripheral wall 4.

  The stress generated during canning increases as the outer wall 4 is approached. In the case of having the above configuration, the buckling stress of the short cell wall 30 increases as the flat cell 21 is located closer to the outer peripheral wall 4. Therefore, according to the above configuration, the honeycomb structure 1 capable of effectively improving the structure strength can be obtained.

  For example, the length of the short cell wall 30 in the flat cell 21 is configured to gradually decrease toward the outer peripheral wall 4 or configured to decrease stepwise toward the outer peripheral wall 4. Can be.

  Other configurations and operational effects are the same as those of the first embodiment.

(Embodiment 4)
The honeycomb structure of Embodiment 4 will be described with reference to FIG.

  As shown in FIG. 7, in the honeycomb structure 1 of the present embodiment, the wall thickness of the cell wall 3 in the outer peripheral reinforcement region 12 is thicker than the wall thickness of the cell wall 3 in the base region 11.

  According to this configuration, the buckling stress per column length of one cell wall 3 constituting the hexagonal cell 2 is larger in the outer peripheral strengthening region 12 than in the base region 11. Therefore, the honeycomb structure 1 of the present embodiment is advantageous in improving the structure strength as compared with the honeycomb structure 1 of the first embodiment, which is an example in which the wall thickness of the cell wall 3 in the outer peripheral reinforcing region 12 is not increased. It is.

Whether or not the wall thickness t1 of the cell wall 3 in the outer peripheral strengthening region 12 is thicker than the wall thickness t of the cell wall 3 in the base region 11 is determined by setting the wall thickness t1 of the cell wall 3 in the outer peripheral strengthening region 12 as follows. This can be confirmed by comparing with the average value t _ave described in the first embodiment.

  Other configurations and operational effects are the same as those of the first embodiment.

(Embodiment 5)
The honeycomb structure of Embodiment 5 will be described with reference to FIG.

  As shown in FIG. 8, in the honeycomb structure 1 of the present embodiment, each of the base region 11 region and the outer peripheral reinforcing region 12 has a reinforcing portion 32 having a corner R surface portion 321 at the cell apex portion 31. Yes. The size of the corner R surface portion 321 in the outer periphery strengthening region 12 is larger than the size of the corner R surface portion 321 in the base region 11.

  According to this configuration, the outer peripheral reinforcing region 12 has a shorter column length of the cell wall 3 between the corner R surface portions 321 than the base region 11. Therefore, in the outer peripheral strengthening region 12, the buckling stress per column length of one cell wall 3 constituting the hexagonal cell 2 is larger than that in the base region 11. Therefore, the honeycomb structure 1 of the present embodiment is advantageous in improving the structure strength as compared with the honeycomb structure 1 of the first embodiment which is an example that does not include the reinforcing portion 32.

  The reinforcing portion 32 described above may be formed on all the cell apex portions 31 of the base region 11 and the outer periphery reinforcing region 12, or even if there is a cell apex portion 31 where the reinforcing portion 32 is not formed in part. Good. The reinforcing portion 32 is a portion where the cell apex portion 31 where the cell walls 3 are connected to each other is thickened. That is, a portion of the cell apex portion 31 that protrudes to the inside of the cell 2 from the extension line 300 that extends the flat surface portion of each cell wall 3 is the reinforcing portion 32. Specifically, the corner R surface portion 321 of the reinforcing portion 32 has a curved surface portion that protrudes toward the cell apex portion 31 on the surface.

The dimension of the corner R surface portion 321 in the base region 11 can be calculated as follows. With respect to each cell vertex portion 31 constituting the center cell 20 and the six cells 2 surrounding the center cell 20, each corner R surface portion 321 formed on each cell vertex portion 31 (either cell 2 outside or cell 2 inside) The radius of the inscribed circle when the inscribed circle in contact with (including FIG. 8) is drawn is obtained (FIG. 8A). The average value r _ave of the radius of the inscribed circle is set as the dimension r of the corner R surface portion 321 in the base region 11. On the other hand, as shown in FIG. 8B, the dimension of the corner R surface portion 321 in the outer periphery strengthening region 12 is the radius r1 of the inscribed circle when an inscribed circle in contact with the corner R surface portion 321 is drawn. Whether or not the size of the corner R surface portion 321 in the outer peripheral strengthening region 12 is larger than the size of the corner R surface portion 321 in the base region 11 depends on the average r1 of the corner R surface portion 321 in the outer peripheral strengthening region 12 described above. This can be confirmed by comparing with the value r _ave .

  Other configurations and operational effects are the same as those of the first embodiment.

(Embodiment 6)
A honeycomb structure of Embodiment 6 will be described with reference to FIGS. 9 and 10.

  As shown in FIG. 9, in the honeycomb structure 1 of the present embodiment, the outer periphery reinforcing region 12 is viewed in a direction along the side L of the virtual regular hexagon H in a cross-sectional view perpendicular to the honeycomb central axis 10. The area of the three-pronged unit 33 including the three cell walls 3 extending radially from the cell apex portion 31 that is jumped one by one along the cell wall 3 is made equal between the adjacent three-pronged units 33. Reinforced structure is included. 9 indicate the positions of the clay supply holes of the mold (not shown) used in manufacturing the honeycomb structure 1 (FIGS. 1, 4, 5, and 7 described above are also included). The same). In addition, the raw material for the cell walls 3 of the honeycomb structure 1 prepared in a clay shape is supplied to the clay supply holes.

  When the cell wall 3 is thickened or the dimension of the corner R surface portion 321 is increased in the outer peripheral reinforcing region 12, the sectional area of the mold slit used when the honeycomb structure 1 is formed increases. As a result, the supply amount of the raw material necessary for forming the cell wall 3 of the outer periphery strengthening region 12 increases, the molding speed becomes slow, and the cell 2 is easily distorted. On the other hand, according to the said structure, the reinforcement structure by which the area was made equivalent between the adjacent three-pronged units 33 is included. Therefore, according to the above configuration, it is easy to reduce the strain in the outer peripheral reinforcing region 12 at the time of forming the honeycomb structure 1, and it is easy to improve the structure strength.

  Specifically, the area of the three-pronged unit 33 described above is an area of a portion surrounded by a thick line as illustrated in FIG. That is, the total cross-sectional area of the three cell walls 3 (including the reinforcing portions 32) that are supplied by the clay supply holes at the time of forming the honeycomb is the area of the portion surrounded by the thick line in FIG. Further, as illustrated in FIG. 10, the boundary between the adjacent trifurcated units 33 is defined by drawing the center line M of the cell wall 3 and dividing the intersection of the adjacent trifurcated units 33 into three.

  When the areas of adjacent three-pronged units 33 are compared, the area of one three-pronged unit 33 is in the range of 0.97 to 1.03 times the area of the other three-pronged unit 33. Since it can be said that it is within a range of errors, it can be said that the areas are equal to each other.

  Other configurations can be the same as those in the fourth embodiment or the fifth embodiment. Other effects are the same as those of the fourth or fifth embodiment.

<Experimental example 1>
As shown in Tables 1 and 2, it has a plurality of cells having a hexagonal cross section, a test body 1C composed of a honeycomb structure whose outer periphery is not reinforced, and a plurality of cells having a hexagonal cross section. Specimens 1 to 15 composed of a honeycomb structure whose outer periphery was reinforced were produced by extrusion molding using a mold. Note that the manufactured honeycomb structure has a cylindrical outer peripheral wall, and each has a honeycomb diameter: 117 mm in diameter, a honeycomb substrate length: 100 mm, and an outer peripheral wall thickness: 0.35 mm.

  Here, as shown in FIG. 11, the test body 1 </ b> C has a cell structure in which regular hexagonal cells 2 are spread from the honeycomb central axis 10 to the outer peripheral wall 4 without the outer peripheral reinforcing region 12. . This test body 1C is an example of a conventional honeycomb structure. On the other hand, the test bodies 1 to 4, 9, and 10 are examples in which the outer peripheral reinforcing region 12 according to FIG. 5 is included and the flat cell 21 is included, but the deformation cell 22 is not included. Moreover, the test bodies 5-8 and 11-15 are the examples which have the outer periphery reinforcement | strengthening area | region 12 according to FIG. 1, and have both the flat cell 21 and the deformation | transformation cell 22. FIG.

  And about each test body, the isostatic strength (the average value of n = 20, below abbreviate | omitted) and the pressure loss were measured.

The pressure loss was measured as follows. As schematically shown in FIG. 12, the piping part 91, the accommodating part 92 in which the honeycomb structure 1 is accommodated, and the enlarged diameter part 93 that connects the piping part 91 and the accommodating part 92 are provided. An evaluation converter 9 was prepared. The diameter φ1 of the piping part 91 was 50.5 mm. The diameter φ2 of the accommodating portion 92 was 123 mm. The length l1 of the enlarged diameter portion 93 was 55 mm. The distance l2 between the one end surface of the honeycomb structure 1 and the enlarged diameter portion 93 on the one end surface side was 5 mm. The distance l3 between the other end face of the honeycomb structure 1 and the enlarged diameter portion 93 on the other end face side was set to 10 mm. The gas flow rate of the exhaust gas flowing through the honeycomb structure 1 was 7 m ³ / min, and the gas temperature was 600 degrees. A 4.6 L V8 engine was used as an engine for generating exhaust gas.

  As shown in Tables 1 and 2, in the test bodies 1 to 4, 9, and 10, h1 <h, p1≈p, and h1 of the flat cells in the same row of the outer peripheral strengthening region are equivalent. In the test bodies 5 to 8 and 11 to 15, h1 <h, h2 <h, p1≈p, and h1 of the flat cell and h2 of the deformed cell in the same row of the outer periphery strengthening region are equivalent. Therefore, the test bodies 1 to 15 are all designed to improve the strength of the structure while suppressing an increase in pressure loss as compared with the test body 1C as a comparative example that does not have the outer periphery strengthening region. confirmed. In addition, the exhaust pipe part 91 connected to a catalytic converter is circular. Therefore, even after the exhaust gas flow spreads at the enlarged diameter portion 93, the exhaust gas flow has a circular shape and flows into the honeycomb structure. The pressure loss when flowing into the honeycomb structure becomes smaller when the cross-sectional area of the honeycomb structure effective for inflow is larger because the flow rate of gas flowing per cell is smaller. On the other hand, if the outer shape of the honeycomb structure is elliptical, the inflow gas is circular and the exhaust gas inflow portion is limited on the short axis side, so that the effective cross-sectional area of the honeycomb structure is reduced. . Therefore, the pressure loss is increased. That is, in the elliptical honeycomb structure, there is a portion on the long axis side where exhaust gas inflow does not occur and is wasted.

  Moreover, when the test bodies 1-15 are compared, the following can be understood. When the test bodies 1 to 4 are compared, it can be seen that the isostatic strength is increased by shortening the length h1 of the short cell wall in the flat cell and increasing the flatness of the flat cell.

  When comparing the test bodies 1 to 4, 9, 10 and the test bodies 5, 7, 11, and 12, the deformed cells are introduced by introducing deformed cells and increasing the number of reinforcing cells by the flat cells in the outer peripheral reinforcing region. It can be seen that a higher isostatic strength can be obtained compared to the case where no is introduced.

  By comparing the test specimens 5, 7, 11, 12 and the test specimens 8, 13, by configuring the length of the short cell wall in the flat cell to be shorter as it approaches the outer peripheral wall in the outer peripheral reinforcement region, It can be seen that isostatic strength can be easily improved while suppressing an increase in pressure loss.

  Comparing the test bodies 1-5, 7, 8 and the test bodies 9-13, the wall thickness of the cell wall in the outer peripheral reinforcement region is made thicker than the wall thickness of the cell wall in the base region. It can be seen that a higher isostatic strength can be obtained by a synergistic effect with the effect of the introduction.

  When the test bodies 3 and 4 and the test bodies 14 and 15 are compared, the size of the corner R surface portion in the outer peripheral reinforcing region is larger than the size of the corner R surface portion in the base region. It can be seen that a higher isostatic strength can be obtained by the synergistic effect.

  When the test body 5 and the test body 6 are compared, when viewed in a direction along the side of the virtual regular hexagon in a cross-sectional view perpendicular to the central axis of the honeycomb, from the cell apex portion that is jumped one by one along the cell wall The area of the three-pronged unit including three cell walls extending radially is equal in the area of the three-pronged unit between the adjacent three-pronged units. The average isostatic strength and the minimum isostatic strength were higher than those of the sample 6 made different. Note that the maximum isostatic strength of Sample 5 and Sample 6 did not change significantly. This is because, when the cross-sectional areas of the trifurcated units are different, many molding defects such as cell warping occurred during extrusion molding of the honeycomb structure.

  The present invention is not limited to the above-described embodiments and experimental examples, and various modifications can be made without departing from the scope of the invention. Moreover, each structure shown by each embodiment and each experiment example can be combined arbitrarily, respectively.

DESCRIPTION OF SYMBOLS 1 Honeycomb structure 10 Honeycomb center axis | shaft 11 Base area | region 12 Outer periphery reinforcement | strengthening area | region 2 Cell 20 Central cell 21 Flat cell 3 Cell wall 30 Short cell wall 4 Outer peripheral wall p Cell pitch p1 of flat cell Cell pitch h The length h1 of the cell wall constituting the direction perpendicular to the side of the virtual regular hexagon In the outer periphery strengthening region, the length H of the short cell wall constituting the direction perpendicular to the side of the virtual regular hexagon H The virtual regular hexagon L The virtual regular hexagon Neighborhood

Claims (7)

A plurality of cells (2) having a hexagonal cross section adjacent to each other, a plurality of cell walls (3) forming the plurality of cells, and an outer peripheral wall provided on the outer periphery of the plurality of cell walls to hold the cell walls (4) and a honeycomb structure (1) comprising:
In a cross-sectional view perpendicular to the honeycomb central axis (10),
A base region having a regular hexagonal center cell (20) configured to include a plurality of regular hexagonal cells, the honeycomb central axis passing through the cell center;
A plurality of the non-regular hexagonal shaped cells, the outer peripheral reinforcing region (12) disposed on the outer periphery of the base region,
When the virtual regular hexagon (H) whose B-axis is inclined by 30 degrees with respect to the central cell is drawn coaxially with the central cell, the outer periphery reinforcing region is perpendicular to the side (L) of the virtual regular hexagon. A non-regular hexagonal flat cell (21) formed using a pair of short cell walls (30) in which the length of the cell wall constituting the cell is shorter than the length of the cell wall in the base region Have multiple
The plurality of flat cells are arranged side by side in a direction along the side of the virtual regular hexagon,
When viewed in the direction along the side of the virtual regular hexagon, the cell pitch of the flat cell is equivalent to the cell pitch of the cell in the base region,
A honeycomb structure (1) in which the lengths of the short cell walls of the flat cells arranged in the same row in the direction along the side of the virtual regular hexagon are equal to each other. The outer peripheral reinforcing region is formed of the virtual regular hexagons extending from the vertices of the virtual regular hexagons on the six first virtual straight lines (V1) respectively connecting the honeycomb central axis and the vertices of the virtual regular hexagons. A deformed cell (22) formed using a first cell wall (341) constituting a direction perpendicular to one of the two sides and a second cell wall (342) constituting a direction perpendicular to the other side. )
The lengths of the first cell wall and the second cell wall of the deformed cell are made shorter than the length of the cell wall in the base region that forms a direction perpendicular to each side of the virtual regular hexagon. And
The length of the first cell wall and the second cell wall of the deformed cell is equal to the length of the short cell wall of the flat cell arranged in the same row in the direction along the side of the virtual regular hexagon. The honeycomb structure according to claim 1.   The honeycomb structure according to claim 1 or 2, wherein a length of the short cell wall in each of the flat cells is shorter as it is closer to the outer peripheral wall.   The honeycomb structure according to any one of claims 1 to 3, wherein the outer peripheral reinforcing region is configured by a region up to any row in at least the fourth row counting from the outer peripheral wall side.   The honeycomb structure according to any one of claims 1 to 4, wherein a wall thickness of the cell wall in the outer peripheral reinforcing region is thicker than a wall thickness of the cell wall in the base region. Each of the base region and the outer periphery reinforcing region has a reinforcing portion (32) having a corner R surface portion (321) at a cell apex portion (31),
The honeycomb structure according to any one of claims 1 to 5, wherein a size of the corner R surface portion in the outer peripheral reinforcing region is larger than a size of the corner R surface portion in the base region. When the outer periphery strengthened region is viewed in a direction along the side of the virtual regular hexagon in a cross-sectional view perpendicular to the honeycomb central axis,
The area of the three-pronged unit (33) configured to include the three cell walls extending radially from the cell apex portion (31) that is jumped one by one along the cell wall is between the adjacent three-pronged units. The honeycomb structure according to any one of claims 1 to 6, wherein the honeycomb structure includes a reinforced structure that is equivalent to each other.