JP2007275873A - Hexagonal cell honeycomb structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hexagonal cell honeycomb structure capable of realizing the enhancement of isostatic strength while the cleaning performance of an exhaust gas is maintained. <P>SOLUTION: The hexagonal cell honeycomb structure 1 possesses a large number of hexagonal cells 3 surrounded by hexagonal lattice shaped cell walls 2 and a cylindrical outer peripheral wall 4 covering an outer peripheral surface. The cell walls 2 has basic cell walls 21 and reinforced cell walls 22 stronger than the basic cell walls 21. The strength reinforcing range 5 including the reinforced cell walls 22 are arranged in an approximately straight line shape in the diameter direction cross section of the hexagonal cell honeycomb structure 1 and of which both the ends are brought into contact with the outer peripheral wall 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hexagonal cell honeycomb structure in which a large number of hexagonal cells surrounded by hexagonal lattice cell walls are provided.

  As a substrate for exhaust gas purification of automobiles, a honeycomb structure having a ceramic material having a high thermal shock resistance as a main component and having a cell wall provided in a lattice shape and a cylindrical outer wall covering the outer peripheral side surface The body is known. This honeycomb structure is used with a catalyst component supported on the surface of cell walls provided in a lattice shape.

  Some honeycomb structures have cell shapes such as a triangle, a quadrangle, and a hexagon. A honeycomb structure with a hexagonal cell shape (hereinafter referred to as a hexagonal cell honeycomb structure) is easier to carry a catalyst on a cell wall with a uniform thickness than one with a triangular or quadrangular cell shape. , Pressure loss can be reduced. Moreover, since an excessive amount of catalyst can be suppressed, the overall weight can be reduced. Therefore, in recent years, the hexagonal cell honeycomb structure has attracted attention from the viewpoint of exhaust gas purification performance.

  However, the hexagonal cell honeycomb structure having excellent exhaust gas purification performance has a problem that the isostatic strength is lower than those of other cell shapes. In particular, when used as a base material for exhaust gas purification of automobiles, if the isostatic strength is insufficient, there is a risk that defects such as chipping and cracking may occur due to vibration impact during press fitting (canning) to the exhaust pipe or when the vehicle is assembled. There is.

As a method for solving the above problem, there is a method for increasing the strength of a hexagonal cell honeycomb structure by increasing the thickness of a cell wall at a specific distance (range) with respect to the outer peripheral wall (see Patent Document 1). ).
However, the hexagonal cell honeycomb structure has a structure in which the pressure loss increases in the portion where the cell wall thickness is increased or the performance of warming up the catalyst supported on the cell wall early (catalyst early warming performance) decreases. There is a possibility that the exhaust gas purification performance of the whole body is lowered.

In addition to the above, as a method of improving the strength of the honeycomb structure, a method of changing the thickness of the cell wall and the outer peripheral wall, or setting a specific range (see Patent Documents 2 and 3), There is a method of setting the intersection radius of the cell walls and the curvature radius of the intersection of the cell wall and the outer peripheral wall within a specific range (see Patent Document 4). In addition, there are methods of variously changing the cell shape of the outer peripheral portion of the honeycomb structure or forming reinforcing ribs in the cells of the outer peripheral portion (see Patent Document 2). There is also a method of closing a specific range of cells with a plug material with respect to the outer peripheral wall (see Patent Document 5).
However, in any case, it cannot be said that the honeycomb structure is improved in strength, balance between strength and performance (for example, exhaust gas purification performance), and the like.

  Therefore, there is a need for a hexagonal cell honeycomb structure that can improve isostatic strength while maintaining excellent exhaust gas purification performance.

Japanese Patent Laid-Open No. 55-155741 JP-A-11-270334 Japanese Patent Laid-Open No. 11-277653 JP 2002-46117 A JP 2004-154768 A

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a hexagonal cell honeycomb structure capable of improving isostatic strength while maintaining exhaust gas purification performance.

The present invention is a hexagonal cell honeycomb structure having a large number of hexagonal cells surrounded by hexagonal lattice-like cell walls and a cylindrical outer peripheral wall covering the outer peripheral side surface.
The cell wall has a basic cell wall and a reinforced cell wall having higher strength than the basic cell wall,
The strength strengthening region including the strengthened cell walls is disposed substantially linearly in the radial cross section of the hexagonal cell honeycomb structure, and both ends thereof are in contact with the outer peripheral wall. It exists in a hexagonal cell honeycomb structure (claim 1).

  The hexagonal cell honeycomb structure of the present invention has a strength strengthening region including the strengthened cell wall having a strength higher than that of the basic cell. The strength-enhancing regions are arranged substantially linearly in the radial cross section of the hexagonal cell honeycomb structure and are formed so that both ends thereof are in contact with the outer peripheral wall. That is, the strength strengthening region constituted by the strengthened cell wall having high strength is formed so as to bridge between any two points on the outer peripheral wall. Therefore, when stress acts on the outer peripheral wall in the hexagonal cell honeycomb structure, the strength strengthening region serves as a beam with respect to the outer peripheral wall, and the acting stress can be dispersed and relaxed. . Therefore, the isostatic strength of the hexagonal cell honeycomb structure can be improved.

  Moreover, the said intensity | strength reinforcement area | region is arrange | positioned substantially linearly as mentioned above. That is, the hexagonal cell honeycomb structure is formed by forming the reinforcing cell wall only in a small and limited portion of a substantially straight shape, rather than forming the reinforcing cell wall having high strength in the whole or a specific large range. The isostatic strength is improved. Therefore, for example, when the strength of the reinforced cell wall is increased by increasing the thickness, even if an increase in pressure loss or a decrease in the early catalyst warm-up performance occurs in the strength-enhanced region, The effect on purification performance is very small. Therefore, the exhaust gas purification performance of the hexagonal cell honeycomb structure can be sufficiently maintained.

  Thus, the hexagonal cell honeycomb structure of the present invention can improve the isostatic strength while maintaining the exhaust gas purification performance by forming the above-described strength-enhancing region.

  In the present invention, the radial section of the hexagonal cell honeycomb structure is a section orthogonal to the axial direction of the hexagonal cell honeycomb structure.

Moreover, it is preferable that a plurality of the strength enhancement regions are provided.
In this case, the isostatic strength of the hexagonal cell honeycomb structure can be further improved.

Moreover, it is preferable that the said strength reinforcement | strengthening area | region is arrange | positioned point-symmetrically with respect to the center of the radial direction cross section of the said hexagonal cell honeycomb structure.
In this case, the isostatic strength of the hexagonal cell honeycomb structure can be improved effectively with a good overall balance.

Moreover, it is preferable that the said strength reinforcement area | region is arrange | positioned so that the center of the radial direction cross section of the said hexagonal cell honeycomb structure may be passed.
In this case, the isostatic strength of the hexagonal cell honeycomb structure can be sufficiently and reliably improved.

Further, it is preferable that the strength-enhancing region is arranged so that at least a part of the hexagonal cell honeycomb structure has a polygon inscribed in the outer peripheral wall in the radial cross section.
In this case, the strength strengthening region can exert an effect as a beam on the entire outer peripheral wall. Therefore, the isostatic strength of the hexagonal cell honeycomb structure can be sufficiently improved with a good balance as a whole.

The thickness of the strengthened cell wall in the strength strengthened region is preferably larger than the thickness of the basic cell wall.
In this case, the strength strengthening region including the strengthening cell wall can surely improve the strength as compared with the region where the basic cell wall exists.

The thickness of the reinforced cell wall is preferably 1.3 to 1.8 times the thickness of the basic cell wall.
When the thickness of the strengthened cell wall is less than 1.3 times the thickness of the basic cell wall, the strength of the strength strengthened region may not be sufficiently improved. On the other hand, when it exceeds 1.8 times, since the thickness of the strengthened cell wall becomes large, the pressure loss in the strength strengthened region may be increased. In addition, the catalyst warm-up performance may be reduced due to an increase in the weight of the reinforcing cell wall. And, there is a possibility that the exhaust gas purification performance of the whole hexagonal cell honeycomb structure is lowered due to these.

Each of the hexagonal cells has six inner corners formed by the cell walls, and the three inner corners surrounding the intersections where only the reinforcing cell walls meet have a substantially arc shape. It is preferable that an R corner portion is provided (claim 8).
That is, when looking at the hexagonal cell formed by being surrounded by the reinforced cell walls, among the six inner corners, only the reinforced cell walls are formed at intersections. It is preferable that there are four inner corners, and the R corners are provided in the four inner corners.
In this case, the strength of the reinforced cell wall can be improved. As a result, the strength-enhancing region formed by connecting the strengthened cell walls can sufficiently and reliably improve the strength as compared with the region where the basic cell walls exist.

Furthermore, it is preferable that the R corners are also provided in the three inner corners surrounding the intersections where the strengthening cell walls and the basic cell walls meet (Claim 9).
That is, when looking at the hexagonal cell formed by being surrounded by the reinforced cell wall, among the six inner corners, the intersection where the reinforced cell wall and the basic cell wall meet. There are two inner corners formed in the part, the two inner corners are also provided with the R corners, and all six inner corners are provided with the R corners. preferable.
In this case, the strength of the reinforced cell wall can be further improved. Thereby, the intensity | strength of the said intensity | strength reinforcement area | region can be improved further.

Moreover, it is preferable that the curvature radius of the said R corner part is 0.15-0.4 mm (Claim 10). The radius of curvature of the R corner is more preferably 0.2 to 0.35 mm (claim 11).
If the radius of curvature of the R corner is less than 0.15 mm, the strength of the reinforced cell wall may not be sufficiently improved. Therefore, there is a possibility that the strength of the strength strengthened region cannot be sufficiently improved. On the other hand, when it exceeds 0.4 mm, the thickness of the cell wall at the R-corner portion increases, so that the pressure loss in the strength strengthening region may increase. In addition, the catalyst warm-up performance may be reduced due to an increase in the weight of the reinforcing cell wall. And, there is a possibility that the exhaust gas purification performance of the whole hexagonal cell honeycomb structure is lowered due to these. Therefore, more preferably, the radius of curvature of the R corner is 0.2 to 0.35 mm.

Moreover, it is preferable that the maximum width of the said strength reinforcement | strengthening area | region is 1-5 mm (Claim 12).
When the maximum width of the strength strengthening region is less than 1 mm, the strength strengthening region may not be able to sufficiently exhibit the effect as a beam on the outer peripheral wall. Therefore, the isostatic strength of the hexagonal cell honeycomb structure may not be sufficiently improved. On the other hand, when the thickness exceeds 5 mm, for example, when the strength of the reinforced cell wall is improved by increasing the thickness, an increase in pressure loss or a decrease in the catalyst early warming performance occurs in the portion, and the hexagonal cell honeycomb There is a possibility that the exhaust gas purification performance of the entire structure may be deteriorated.
The maximum width of the strength strengthened region is the maximum width of the region including the strengthened cell walls in the radial cross section of the hexagonal cell honeycomb structure.

Moreover, it is preferable that the thickness of the said outer peripheral wall is 0.2-0.6 mm.
When the thickness of the outer peripheral wall is less than 0.2 mm, the strength of the outer peripheral wall itself cannot be sufficiently secured, and the isostatic strength of the hexagonal cell honeycomb structure may be lowered, or the product may be conveyed. There is a risk of chipping. On the other hand, if it exceeds 0.6 mm, the temperature difference between the inside and outside of the outer peripheral wall becomes large, and the thermal shock resistance may be reduced.

The basic cell wall preferably has a thickness of 50 to 125 μm.
When the thickness of the basic cell wall is less than 50 μm, the strength of the basic cell wall itself cannot be sufficiently secured, and the isostatic strength of the hexagonal cell honeycomb structure may be lowered. On the other hand, when it exceeds 125 μm, the pressure loss of the hexagonal cell honeycomb structure may increase. In addition, the catalyst early warming performance may be reduced due to the increase in the weight of the basic cell wall. And, there is a possibility that the exhaust gas purification performance of the whole hexagonal cell honeycomb structure is lowered due to these.

Example 1
A hexagonal cell honeycomb structure according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 to 4, the hexagonal cell honeycomb structure 1 of this example includes a large number of hexagonal cells 3 surrounded by a hexagonal lattice-like cell wall 2 and a cylindrical outer peripheral wall covering the outer peripheral side surface. 4.
The cell wall 2 includes a basic cell wall 21 and a reinforced cell wall 22 having higher strength than the basic cell wall 21, and the strength-enhanced region 5 including the reinforced cell wall 22 is a radial section of the hexagonal cell honeycomb structure 1. Are arranged in a substantially straight line, and both ends thereof are in contact with the outer peripheral wall 4.
This will be described in detail below.

  As shown in FIG. 1, the hexagonal cell honeycomb structure 1 of this example is used as a substrate for exhaust gas purification of automobiles. The hexagonal cell honeycomb structure 1 is made of a ceramic material mainly composed of cordierite, and has dimensions of an outer diameter of 103 mm and a length of 130 mm.

  Further, as shown in the figure, the hexagonal cell honeycomb structure 1 has an outer peripheral side surface covered with a cylindrical outer peripheral wall 4. Further, the inside of the outer peripheral wall 4 is constituted by cell walls 2 arranged in a hexagonal lattice shape and a large number of hexagonal cells 3 partitioned by the cell walls 2. The outer peripheral wall 4 has a thickness of 0.4 mm.

  Further, as shown in FIG. 2, the cell wall 2 includes a basic cell wall 21 and a reinforced cell wall 22. The reinforced cell wall 22 is thicker and stronger than the basic cell wall 21. In addition, the thickness a of the basic cell wall 21 of this example is 90 μm, and the thickness b of the reinforced cell wall 22 is 117 μm. Therefore, the thickness of the reinforcing cell wall 22 is 1.3 times the thickness of the basic cell wall 21. The cell pitch c is 1.11 mm.

  Further, as shown in the figure, the hexagonal cell honeycomb structure 1 has a strength strengthening region 5 including a strengthened cell wall 22 in the radial cross section. The strength strengthening region 5 including the strengthening cell wall 22 has higher strength than the region where the basic cell wall 21 exists. The maximum width A of the strength strengthening region 5 of this example is 1.42 mm. The radial cross section of the hexagonal cell honeycomb structure 1 is a cross section orthogonal to the axial direction. The maximum width A of the strength strengthening region 5 is the maximum width of the region including the strengthening cell wall 22.

  As shown in FIGS. 3 and 4, the hexagonal cell honeycomb structure 1 as a whole is provided with a plurality of strength strengthening regions 5, each of which is arranged substantially linearly. Further, both ends of the strength enhancing region 5 are in contact with the outer peripheral wall 4. That is, the strength enhancement region 5 is provided so as to bridge between any two points on the outer peripheral wall 4.

Further, as shown in the figure, the plurality of strength enhancing regions 5 are arranged so as to exhibit a polygon inscribed in the outer peripheral wall 4 in the radial cross section. That is, the strength strengthening region 5 of this example is arranged so as to exhibit a hexagonal shape inscribed in the outer peripheral wall 4. Further, the strength enhancement region 5 is provided point-symmetrically with respect to the center 11 of the radial cross section.
FIG. 4 illustrates only the outer peripheral wall 4 and the strength strengthening region 5 in order to clarify the arrangement shape of the strength strengthening region 5 in the radial cross section of the hexagonal cell honeycomb structure 1.

Next, a method for manufacturing the hexagonal cell honeycomb structure 1 of this example will be briefly described.
In manufacturing the hexagonal cell honeycomb structure 1, the manufacturing process itself can adopt the same process as the conventional one. That is, the cordierite raw material constituting the hexagonal cell honeycomb structure 1 is extruded into a honeycomb shape as a formed body, cut into a predetermined length, and the formed body is dried and fired. As described above, the hexagonal cell honeycomb structure 1 is obtained.

  Here, as a characteristic of the hexagonal cell honeycomb structure 1 of the present example, a slit groove having a shape corresponding to the arrangement shape of the basic cell wall 21 and the reinforced cell wall 22 is provided as the mold during the extrusion molding. In addition, an extrusion mold (not shown) is used. The slit groove can be formed by a method such as electric discharge machining or laser machining.

Next, isostatic strength was measured in order to evaluate the strength characteristics of the hexagonal cell honeycomb structure 1 (sample E1) of this example.
For comparison, a comparative hexagonal cell honeycomb structure (sample C1) in which all the cell walls 2 are configured by the basic cell walls 21 without forming the strength strengthening region 5 including the reinforcing cell walls 22 is prepared. Was evaluated.

  Isostatic strength is measured by placing aluminum plates on both end faces of the hexagonal cell honeycomb structure, wrapping the outer periphery with a rubber tube, sealing the end of the tube with tape, and using as a measurement sample. And this sample was put in the hydraulic container, water was introduce | transduced and the pressure was increased and the pressure at the time of destruction was made into isostatic strength.

  The measurement result of isostatic strength is shown in FIG. As is known from FIG. 5, the isostatic strength of the sample C1 which is the conventional product is about 1 MPa, whereas the isostatic strength of the sample E1 which is the product of the present invention is about 3.5 MPa. That is, the product of the present invention has an isostatic strength of about 3 times that of the conventional product.

Next, based on the above results, the effect of the hexagonal cell honeycomb structure 1 (sample E1) of this example will be described.
The hexagonal cell honeycomb structure 1 of the present example is thicker than the basic cell wall 21, and a plurality of strength strengthening regions 5 constituted by the strengthened cell walls 22 having a high strength are formed between any two points on the outer peripheral wall 4. It is formed to bridge. Therefore, when stress acts on the outer peripheral wall 4 in the hexagonal cell honeycomb structure 1, the strength strengthening region 5 serves as a beam with respect to the outer peripheral wall 4, and the acting stress can be dispersed and relaxed. . Therefore, the hexagonal cell honeycomb structure 1 of the present example has a higher isostatic strength than the conventional one.

  Moreover, the intensity | strength reinforcement area | region 5 is arrange | positioned substantially linearly. That is, the hexagonal cell honeycomb structure 1 is not formed by forming the reinforced cell wall 22 only in a small and limited portion of a substantially straight line, instead of forming the reinforced cell wall 22 having high strength in the whole or in a specific large range. The isostatic strength is improved. Therefore, even if an increase in pressure loss or a decrease in early catalyst warm-up performance occurs in the strength enhancement region 5, the influence on the exhaust gas purification performance of the entire hexagonal honeycomb structure 1 is very small. Therefore, the exhaust gas purification performance of the hexagonal cell honeycomb structure 1 can be sufficiently maintained.

Further, in this example, the strength enhancement region 5 is arranged point-symmetrically with respect to the center 11 of the radial cross section. Therefore, the isostatic strength of the hexagonal cell honeycomb structure 1 can be improved effectively with a good balance as a whole.
Further, the strength enhancing region 5 is arranged so as to exhibit a polygon inscribed in the outer peripheral wall 4 in the radial cross section. Therefore, the strength strengthening region 5 can exhibit an effect as a beam with respect to the entire outer peripheral wall 4. Therefore, the isostatic strength of the hexagonal cell honeycomb structure 1 can be improved sufficiently with a good overall balance.

  Thus, the hexagonal cell honeycomb structure 1 of this example can improve the isostatic strength while maintaining the exhaust gas purification performance.

(Example 2)
This example is an example in which the configuration of the reinforcing cell walls 22 is changed in the hexagonal cell honeycomb structure 1 of the first embodiment. This will be described with reference to FIG.

In this example, as shown in FIG. 6, each hexagonal cell 3 has six inner corners 23 formed by the cell wall 2. In addition, the three inner corners 23 surrounding each intersection of the reinforcement intersections 241 where only the reinforcement cell walls 22 merge are provided with R-shaped R corners 231 having a substantially arc shape.
That is, when attention is paid to one hexagonal cell 3 formed surrounded by the reinforcing cell walls 22, among the six inner corner portions 23, the reinforcing intersections 241 where only the reinforcing cell walls 22 merge are formed. There are four inner corners 23, and the four inner corners 23 are provided with R corners 231. Further, when paying attention to one reinforced intersection 241, as described above, the three inner corners 23 of the three adjacent cells 3 surround the intersection, but the R corners 231 are formed in all the three inner corners 23. Is provided.
In addition, the thickness a of the basic cell wall 21 of this example is 90 μm, and the thickness b of the reinforced cell wall 22 is 117 μm. Further, the radius of curvature of the R corner portion 231 is 0.25 mm.
Other configurations are the same as those in the first embodiment.

In this case, the strength of the reinforced cell wall 22 can be improved by providing the R corner portions 231 at the three inner corner portions 23 that surround the reinforcing intersections 241. Therefore, the strength strengthening region 5 configured by connecting the strengthening cell walls 22 can sufficiently and reliably improve the strength as compared with the region where the basic cell walls 21 exist.
The other functions and effects are the same as those of the first embodiment.

(Example 3)
This example is an example in which the strength of the reinforced cell walls 22 and the strength strengthening region 5 is further improved in the hexagonal cell honeycomb structure 1 of the second embodiment. This will be described with reference to FIG.
In this example, as shown in FIG. 7, in addition to the three inner corners 23 surrounding each intersection of the reinforcing intersections 241 where only the reinforcing cell walls 22 meet, boundary intersections where the reinforcing cell walls 22 and the basic cell walls 21 merge. R corners 231 are also formed in the three inner corners 23 surrounding each intersection of 242.
That is, when attention is paid to one hexagonal cell 3 formed surrounded by the reinforcing cell walls 22, among the six inner corner portions 23, the reinforcing intersections 241 where only the reinforcing cell walls 22 merge are formed. Furthermore, there are two inner corners 23 formed at the boundary intersection 242 where the reinforced cell wall 22 and the basic cell wall 21 merge. The inner corner portion 23 is also provided with an R corner portion 231. That is, the R corner portion 231 is provided in all six inner corner portions 23.
Other configurations are the same as those of the second embodiment.

In this case, in addition to the three inner corner portions 23 surrounding each strengthening intersection 241, the R corner portions 231 are also provided in the three inner corner portions 23 surrounding each boundary intersection 242, thereby increasing the strength of the strengthening cell wall 22. Further improvement can be achieved. Therefore, the strength strengthening region 5 configured by connecting the strengthening cell walls 22 can further improve the strength as compared with the region where the basic cell walls 21 exist.
The other effects are the same as those of the second embodiment.

Example 4
This example is an example in which the arrangement shape of the strength strengthening region 5 is changed in the hexagonal cell honeycomb structure 1 of the first embodiment. This will be described with reference to FIGS.

8 and 9 are examples in which the strength-enhancing region 5 is disposed so as to pass through the center 11 of the radial cross section of the hexagonal cell honeycomb structure 1. The two strength enhancement regions 5 are arranged so as to be orthogonal at the center 11.
In addition, in FIG. 10, the strength-enhancing region 5 is arranged so as to exhibit two triangles inscribed in the outer peripheral wall 4. The two triangles are arranged with the inclination shifted by 180 ° with the center 11 of the radial cross section as the axis.

Further, in FIG. 11, the strength strengthening region 5 is arranged so as to exhibit two hexagons inscribed in the outer peripheral wall 4. The two hexagons are arranged with an inclination of 30 ° about the center 11 of the radial section.
Moreover, in FIG. 12, the intensity | strength reinforcement area | region 5 is arrange | positioned so that a square grid | lattice form may be exhibited. A part of the strength enhancing region 5 is arranged so as to exhibit a quadrilateral inscribed in the outer peripheral wall 4.
In addition, the intensity | strength reinforcement area | region 5 of this example is provided point-symmetrically with respect to the center 11 of radial direction cross section.

In any case, the strength strengthening region 5 serves as a beam with respect to the outer peripheral wall 4 and can sufficiently exhibit the effect of improving the isostatic strength of the hexagonal cell honeycomb structure 1.
The other functions and effects are the same as those of the first embodiment.

  In addition, the hexagonal cell honeycomb structure 1 of the present example shows an example of the arrangement shape of the strength strengthening region 5. Therefore, the hexagonal cell honeycomb structure of the present invention is not limited to these, and various arrangement shapes can be adopted.

FIG. 3 is an explanatory view showing a configuration of a hexagonal cell honeycomb structure in Example 1. Explanatory drawing which shows the basic cell wall and reinforcement | strengthening cell wall in Example 1. FIG. FIG. 3 is an explanatory view showing a part of a radial cross section of a hexagonal cell honeycomb structure in Example 1. Explanatory drawing which shows the arrangement | positioning shape of the intensity | strength reinforcement area | region in Example 1. FIG. FIG. 3 is an explanatory diagram showing measurement results of isostatic strength in Example 1. Explanatory drawing which shows the basic cell wall and reinforcement | strengthening cell wall in Example 2. FIG. Explanatory drawing which shows the basic cell wall and reinforcement | strengthening cell wall in Example 3. FIG. Explanatory drawing which is a part of radial direction cross section of the hexagonal cell honeycomb structure in Example 4, and shows the example of arrangement | positioning shape of an intensity | strength reinforcement area | region. Explanatory drawing which shows the example of arrangement | positioning shape of the intensity | strength reinforcement area | region in Example 4. FIG. Explanatory drawing which shows the example of arrangement | positioning shape of the intensity | strength reinforcement area | region in Example 4. FIG. Explanatory drawing which shows the example of arrangement | positioning shape of the intensity | strength reinforcement area | region in Example 4. FIG. Explanatory drawing which shows the example of arrangement | positioning shape of the intensity | strength reinforcement area | region in Example 4. FIG.

Explanation of symbols

1 hexagonal cell honeycomb structure 2 cell wall 21 basic cell wall 22 reinforced cell wall 3 cell 4 outer peripheral wall 5 strength strengthening region

Claims (14)

In a hexagonal cell honeycomb structure having a large number of hexagonal cells surrounded by hexagonal lattice-like cell walls and a cylindrical outer peripheral wall covering the outer peripheral side surface,
The cell wall has a basic cell wall and a reinforced cell wall having higher strength than the basic cell wall,
The strength strengthening region including the strengthened cell walls is disposed substantially linearly in the radial cross section of the hexagonal cell honeycomb structure, and both ends thereof are in contact with the outer peripheral wall. Hexagonal cell honeycomb structure.   2. The hexagonal cell honeycomb structure according to claim 1, wherein a plurality of the strength-enhancing regions are provided.   3. The hexagonal cell honeycomb structure according to claim 1, wherein the strength-enhancing region is arranged point-symmetrically with respect to a center of a radial cross section of the hexagonal cell honeycomb structure.   The hexagonal cell honeycomb structure according to any one of claims 1 to 3, wherein the strength-enhancing region is disposed so as to pass through a center of a radial section of the hexagonal cell honeycomb structure.   In any 1 paragraph of Claims 1-4, the above-mentioned strength strengthening field is arranged so that at least one part may present the polygon which inscribed in the above-mentioned peripheral wall in the section of the diameter direction of the above-mentioned hexagonal cell honeycomb structure. A hexagonal cell honeycomb structure characterized by that.   The hexagonal cell honeycomb structure according to any one of claims 1 to 5, wherein a thickness of the reinforcing cell wall in the strength strengthening region is larger than a thickness of the basic cell wall.   7. The hexagonal cell honeycomb structure according to claim 6, wherein the thickness of the reinforced cell wall is 1.3 to 1.8 times the thickness of the basic cell wall.   The hexagonal cell according to any one of claims 1 to 7, wherein each of the hexagonal cells has six inner corners formed by the cell walls, and each of the three cells surrounding each intersection portion where only the reinforcing cell walls meet. The hexagonal cell honeycomb structure according to claim 1, wherein an R corner portion having a substantially arc shape is provided in the inner corner portion.   The hexagonal cell honeycomb according to claim 8, wherein the R corner portion is also provided in three inner corner portions surrounding each intersection portion where the reinforcing cell wall and the basic cell wall meet. Structure.   The hexagonal cell honeycomb structure according to claim 8 or 9, wherein a radius of curvature of the R corner is 0.15 to 0.4 mm.   The hexagonal cell honeycomb structure according to claim 8 or 9, wherein a radius of curvature of the R corner is 0.2 to 0.35 mm.   The hexagonal cell honeycomb structure according to any one of claims 1 to 11, wherein a maximum width of the strength-enhancing region is 1 to 5 mm.   The hexagonal cell honeycomb structure according to any one of claims 1 to 12, wherein the outer peripheral wall has a thickness of 0.2 to 0.6 mm.   The hexagonal cell honeycomb structure according to any one of claims 1 to 13, wherein the basic cell wall has a thickness of 50 to 125 µm.

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