JP4455909B2 - Honeycomb structure and manufacturing method thereof - Google Patents

Description

  The present invention relates to a honeycomb structure and a manufacturing method thereof. More specifically, the present invention relates to a honeycomb structure that is excellent in mechanical strength of an outer wall portion and in which molding defects such as warping and distortion of partition walls are effectively prevented, and a manufacturing method thereof.

  There is an increasing need to remove particulates and harmful substances in exhaust gas from internal combustion engines, boilers and the like from the exhaust gas in consideration of environmental impact. In particular, regulations regarding the removal of particulate matter emitted from diesel engines are in a direction to be strengthened both in Europe, the United States, and Japan, and a collection filter (hereinafter sometimes referred to as DPF) for removing particulate matter. A honeycomb filter using a honeycomb structure is used. A honeycomb filter using a honeycomb structure is also used for filtering liquid such as water and sewage.

  In general, such a honeycomb structure covers partition walls 64 (cell walls) having a honeycomb structure forming a large number of cells 63 and an outer periphery thereof, as shown in FIGS. 17 (a) and 17 (b). It is comprised from the outer wall 62 (outer peripheral skin layer). Fig. 17 (a) is a perspective view schematically showing a conventional honeycomb structure, and Fig. 17 (b) is a plan view schematically showing one end face of the honeycomb structure of Fig. 17 (a). is there. When the honeycomb structure 61 is used as a honeycomb filter, one opening of a predetermined cell and the other opening of the remaining cells are alternately sealed. As a result, when the fluid to be treated flows from one end face (one opening of a predetermined cell) of the honeycomb structure 61, the fluid to be treated passes through the porous partition wall 64 and is adjacent to the cell 63 ( The remaining cells) and flow out from the other end face (the other opening of the remaining cells). At that time, the partition wall 64 functions as a filter and captures particulate matter contained in the fluid to be treated. In order to compensate for such a decrease in the strength of the honeycomb structure 61, for example, although not shown, a cylinder that extends from one end face of the honeycomb structure to the other end face in the vicinity of the inner periphery of the outer skin layer. A technique for providing a circular reinforcing layer in a circular shape is disclosed (for example, see Patent Document 1).

  As a method for manufacturing such a conventional honeycomb structure, for example, a honeycomb formed body 82 is obtained by continuous extrusion using a honeycomb structure forming apparatus as shown in FIG. A method of firing the molded body 82 is used (see, for example, Patent Document 2). Here, FIG. 18 is a vertical sectional view schematically showing a honeycomb structure forming apparatus used in manufacturing a conventional honeycomb structure. The honeycomb structure forming apparatus 70 includes a base 74 having a back hole 73 for introducing a forming raw material and a slit 72 for extruding the introduced forming raw material, and a presser disposed on the downstream side (the slit 72 side) of the base 74. A plate 75 is provided.

In extrusion molding by the honeycomb structure forming apparatus 70, the forming raw material is extruded from the upstream side (back hole 73 side) of the die 74 to the downstream side (slit 72 side) through the die 74 by an extruder (not shown). . The forming raw material extruded from the slit 83 in the inner part, which is open on the downstream side, forms a honeycomb structure (cell structure portion) in which a plurality of cells are partitioned. On the other hand, the forming raw material extruded from the slit 84 in the outer portion of the base 74 is crushed by the action of the gap portion 77 and the direction of travel is changed from the direction of extrusion, and the press plate 75 is opened again. The advancing direction is changed to the extrusion direction, and an outer wall surrounding the cell is formed. In this way, a honeycomb formed body 82 is obtained, and the obtained honeycomb formed body 82 is fired to manufacture a honeycomb structure. The pressing jig 78 and the back pressing plate 79 are holders for fixing the base 74 and the pressing plate 75.
JP 11-268018 A JP 2002-283327 A

  However, when a honeycomb structure is manufactured by the above-described method, the partition walls constituting the honeycomb structure (cell structure portion) may be twisted or distorted in the cross section perpendicular to the axial direction of the honeycomb structure, and the forming accuracy may be increased. For example, there is a problem that the roundness of the molded body is deteriorated. The cell structure portion in which such warping or distortion has occurred is not preferable because the isostatic strength is lowered and the strength of the honeycomb structure is lowered. Further, for example, when the honeycomb structure is used as a DPF or the like, a portion where the filtration function does not work is generated, which is not preferable because the performance is lowered. In particular, when the honeycomb structure is used as a catalyst carrier or a filter, there is a demand to reduce the partition wall thickness for the purpose of reducing pressure loss and improving exhaust gas purification efficiency. As the thickness becomes thinner, the above-mentioned problem of warping and distortion becomes more prominent. In addition, the ceramic honeycomb structure disclosed in Patent Document 1 requires processing on the die itself for extrusion molding, and its manufacturing process is complicated and expensive, and the shape of one shape from one die is increased. There was a problem that only a honeycomb structure could be manufactured.

  Further, in order to prevent breakage during handling of the honeycomb structure, there is a demand to increase the thickness of the outer wall for the purpose of improving the mechanical strength of the outer wall (outer wall portion) covering the outer periphery of the cell structure portion. However, when the thickness of the outer wall is simply increased, the above-mentioned problem of warping and distortion becomes more prominent as the amount of molding raw material extruded as the outer wall during extrusion molding increases. Thus, there is a trade-off between preventing twisting and distortion of the partition walls that make up the cell structure and improving the mechanical strength by increasing the thickness of the outer wall. It was extremely difficult.

  The present invention has been made in view of such problems of the prior art, and has a honeycomb structure excellent in the mechanical strength of the outer wall portion and effectively prevented molding defects such as twisting and distortion of the partition walls and the like. A manufacturing method is provided.

  As a result of earnest research to solve the above-mentioned problems, the inventor has two or more hollow cylindrical shapes in which the outer wall portion disposed on the outer periphery of the cell structure portion is stacked in the radial direction of the cell structure portion. The inventors have found that the above object can be achieved by using an outer wall to complete the present invention. That is, according to the present invention, the following honeycomb structure and the manufacturing method thereof are provided.

  [1] A honeycomb structure including a cylindrical cell structure portion in which a plurality of cells serving as fluid flow paths are defined by porous partition walls, and an outer wall portion disposed on the outer periphery of the cell structure portion A honeycomb structure (hereinafter referred to as "first invention"), wherein the outer wall portion is composed of two or more hollow cylindrical outer walls laminated in the radial direction of the cell structure portion. Sometimes).

  [2] The honeycomb structure according to [1], wherein each of the outer walls constituting the outer wall portion is fired and integrated.

  [3] The outer wall portion is an inner layer outer wall that is the one outer wall disposed so as to cover the cell structure portion, and the other outer wall that is laminated on the outer peripheral surface of the inner layer outer wall. The honeycomb structure according to [1] or [2], which is configured by the outer layer outer wall described above.

  [4] The honeycomb structure according to [3], wherein a thickness of the inner layer outer wall constituting the outer wall portion is thinner than a thickness of the outer layer outer wall.

  [5] The honeycomb according to [3] or [4], wherein a thickness of the inner layer outer wall constituting the outer wall portion is 0.3 to 4 times a thickness of the partition wall constituting the cell structure portion. Structure.

  [6] The honeycomb structure according to any one of [1] to [5], wherein the cell structure portion and the outer wall portion are made of a material mainly composed of ceramics and / or metal.

  [7] The above [1] to [6], wherein at least one of the two or more outer walls constituting the outer wall portion is made of a material different from the material constituting the cell structure portion. ] The honeycomb structure according to any one of the above.

  [8] A predetermined opening of the cell at one end of the tubular cell structure and a remaining opening of the cell at the other end are sealed by a sealing member and used as a filter The honeycomb structure according to any one of [1] to [7].

  [9] The honeycomb structure according to any one of [1] to [8], wherein a catalyst is supported on a surface of the partition wall and / or a pore surface inside the partition wall constituting the cell structure portion.

  [10] The honeycomb structure according to [9], wherein the catalyst has a function of purifying automobile exhaust gas.

  [11] A molding raw material is extrusion-molded, and is disposed on the outer periphery of a cylindrical unfired cell structure portion in which a plurality of cells serving as fluid flow paths are partitioned by partition walls, and the unfired cell structure portion A honeycomb structure manufacturing method for obtaining a honeycomb formed body composed of an unfired outer wall and firing the obtained honeycomb formed body to obtain a honeycomb structure, wherein at least a predetermined forming raw material is The predetermined molding raw material introduced and introduced from the back hole of the plate-shaped base in which a back hole for introducing the molding raw material is formed on the surface and a slit communicating with the back hole is formed on the other surface Is extruded from the slit of the base to form the unfired cell structure, and the remaining forming raw material is extruded into two or more hollow cylinders on the outer periphery of the unfired cell structure. Diameter of firing cell structure A method for manufacturing a honeycomb structure (hereinafter, referred to as “second invention”) in which the unfired outer wall portion composed of two or more unfired outer walls laminated to each other is formed to obtain the honeycomb formed body. ).

  [12] The unfired outer wall portion is laminated on the unfired inner layer outer wall which is the unfired outer wall disposed so as to cover the unfired cell structure portion, and the outer peripheral surface of the unfired inner layer outer wall. The method for manufacturing a honeycomb structured body according to [11], including one or more unfired outer layer outer walls which are the other unfired outer walls.

  [13] At least one of the unfired outer walls of the two or more unfired outer walls is extruded using a forming raw material of a material different from the predetermined material for forming the unfired cell structure. The method for manufacturing a honeycomb structure according to [11] or [12].

  [14] Outer wall forming means is disposed on the other surface side of the die so as to form two or more concentric annular extrusion ports, and the remaining molding raw material is supplied from the two or more extrusion ports. The method for manufacturing a honeycomb structured body according to any one of [11] to [13], wherein the unfired outer wall portion is formed by extrusion.

[ 15 ] When forming the unfired outer layer outer wall , a gap between the forming raw material for forming the unfired outer layer outer wall and the forming raw material for forming the unfired inner layer outer wall, and / or two or more of the unfired outer layer outer walls. The honeycomb structure according to any one of [12] to [ 14 ], wherein a gap between the forming raw materials forming the outer wall of the fired outer layer is controlled.

[ 16 ] In the case where one unfired outer layer outer wall is extruded and formed on the outer periphery of the unfired inner layer outer wall, the outer wall portion forming means corresponds to the size of the inner periphery of the unfired outer layer outer wall. A plate-like member formed with one or more forming raw material passage holes through which an inner peripheral through hole and a part of the remaining forming raw material pass, and an outer peripheral outer periphery through hole corresponding to the outer periphery size of the unfired outer layer outer wall And the plate-like member and the presser plate are separated from each other by a predetermined gap in the extrusion direction of the forming raw material, and the outer layer inner peripheral through hole and the outer layer outer peripheral through The center of the hole is disposed on the other surface side of the base so that the center of the forming raw material is positioned on the same axis, and the gap between the base and the plate-shaped member; and It is formed by the gap between the plate member and the holding plate A method for manufacturing a honeycomb structure according to [14] or [15] from two of said extrusion port of concentric annular forming said unfired inner outer wall and said unfired layer outer wall extruded was.

[ 17 ] When extruding two or more unfired outer layer outer walls on the outer peripheral side of the unfired inner layer outer wall, the outer wall portion forming means corresponds to the size of the inner periphery of the unfired outer layer outer wall. Of the two or more plate-like members formed with one or more molding raw material passage holes through which the outer layer inner peripheral through hole and a part of the remaining molding raw material pass, and the outermost outer wall of the two or more unfired outer layers. An outer layer outer peripheral through-hole corresponding to the size of the outer periphery of the unfired outer layer outer wall on the outer periphery, and two or more of the plate-like members and the pressing plate are extruded from the forming raw material. The other surface of the die so that a center of the outer layer inner peripheral through hole and the outer layer outer peripheral through hole is located on the same axis in the extrusion direction of the forming raw material with a predetermined gap in the direction. The base and the plate-like member. A gap between adjacent plate-like members, and three or more concentric annular extrusion ports formed by a gap between the plate-like member and the pressing plate. The method for manufacturing a honeycomb structured body according to the above [14] or [15] , wherein the outer wall of the unfired outer layer is extruded and formed.

[ 18 ] The unfired outer layer outer wall constituting the unfired outer wall portion is extruded so as to be in contact with an outer peripheral surface of the unfired inner layer outer wall constituting the unfired outer wall portion at an angle of 30 to 90 °. The method for manufacturing a honeycomb structure according to any one of [12] to [ 17 ], wherein the honeycomb structure is formed.

[ 19 ] The plate-like member and the pressing plate can be detached from the base, and the plate-like member and / or the pressing plate can be replaced with another plate-like member having a different shape of the outer peripheral inner circumferential through hole and / or Alternatively, the honeycomb structure according to any one of [11] to [ 18 ], wherein the outer layer outer peripheral through hole may be replaced with another holding plate and the unfired outer wall portion having a different shape may be formed. Manufacturing method.

  The honeycomb structure of the present invention is excellent in the mechanical strength of the outer wall portion and effectively prevents molding defects such as twisting and distortion of the partition walls. In addition, the honeycomb structure manufacturing method of the present invention can manufacture such a honeycomb structure easily and at low cost.

  Hereinafter, embodiments of a honeycomb structure of the present invention and a manufacturing method thereof will be described in detail with reference to the drawings. However, the present invention is not construed as being limited thereto, and the scope of the present invention is not limited. Various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art without departing from the scope.

  FIG. 1 is a perspective view schematically showing one embodiment of a honeycomb structure of the present invention (first invention), and FIG. 2 schematically shows one end face of the honeycomb structure 1 shown in FIG. FIG. As shown in FIGS. 1 and 2, the honeycomb structure 1 of the present embodiment includes a cylindrical cell structure portion 2 in which a plurality of cells 6 serving as fluid flow paths are partitioned by porous partition walls 4. A honeycomb structure 1 having an outer wall 3 disposed on the outer periphery of the cell structure 2, the outer wall 3 having two hollow cylindrical layers stacked in the radial direction of the cell structure 2. The outer wall 5 is configured as described above. With this configuration, even when the thickness of the outer wall portion 3 is increased, molding defects such as twisting and distortion of the partition walls 4 constituting the cell structure portion 2 are effectively prevented, and molding accuracy is excellent. The honeycomb structure 1 can be obtained. Furthermore, it is possible to increase the thickness of the outer wall 3 while maintaining such high molding accuracy, and the mechanical strength of the outer wall 3 can be improved. 1 and 2, the outer wall 3 is shown as an example in which two hollow cylindrical outer walls 5 are laminated in the radial direction of the cell structure 2. For example, as shown in FIG. The outer wall 3 may be one in which three hollow cylindrical outer walls 5 are laminated in the radial direction of the cell structure 2, and although not shown, four or more hollow cylindrical outer walls are provided. May be laminated in the radial direction of the cell structure. The honeycomb structure 1 of the present embodiment can be suitably used as a filter for filtering liquid such as water and sewage, a filter for removing particulate matter discharged from a diesel engine, a catalyst carrier, and the like.

  In general, when a honeycomb structure is manufactured, a method of extruding a predetermined forming raw material to obtain a honeycomb formed body and firing the obtained honeycomb formed body is used. Due to the unfired outer wall that is extruded to the outer periphery of the structure, the unfired cell structure that has just been formed may be pushed inward and deformed or pulled in the extrusion direction. In the honeycomb structure 1 of the present embodiment, the outer wall portion 3 is composed of two or more outer walls 5 although there are cases where molding defects such as twisting and distortion occur in the unfired cell structure portion constituting the body. Thus, it is possible to disperse the stress applied to the unfired cell structure at the time of extrusion molding. Moreover, as compared with the ceramic honeycomb structure shown in Patent Document 1, the manufacturing process is simpler and the outer wall of the outer peripheral skin layer (outer wall portion) is easier to manufacture than the one provided with the reinforcing layer in the vicinity of the inner periphery. The mechanical strength of the part can be further improved.

  Further, in the case where a stress comparable to the stress applied to the unfired cell structure portion manufactured by the conventional manufacturing method is allowed, in the honeycomb structure 1 of the present embodiment, the thickness of the outer wall portion 3 is increased. The thickness can be increased, and the mechanical strength of the outer wall 3 can be improved while maintaining the forming accuracy of the honeycomb structure 1.

  In the honeycomb structure 1 of the present embodiment, although not particularly limited, it is preferable that the respective outer walls 5 constituting the outer wall portion 3 are fired and integrated. In this way, two or more outer walls 5 laminated in the radial direction of the cell structure 2 are substantially integrated, specifically, two or more outer walls 5 are laminated at the stage of extruding a molding material. However, by firing and integrating them, the mechanical strength of the outer wall portion 3 can be made comparable to that of an integrally molded product having the same thickness. Further, by extruding at least one outer wall 5 of the two or more outer walls 5 constituting the outer wall portion 3 using a molding raw material of a material different from the material for molding the cell structure portion 2. A homogeneous heterogeneous material can be added to the outer wall 5, and the outer wall 5 can have another function. For example, by extruding a silica-rich molding raw material different from the material for molding the cell structure portion 2 from different flow paths and molding at least one outer wall 5, the outer wall 5 is made water resistant, for example, When a liquid is used as the fluid passing through the cells 6, it is possible to effectively prevent the liquid from leaking from the outer peripheral side of the outer wall 5 to the outside of the honeycomb structure 1. Further, by controlling the thermal conductivity of the outer wall 5, it is possible to make it difficult to radiate heat. Furthermore, in the honeycomb structure 1 of the present embodiment, the orientation between the outer walls 5 can be given and the structure can be controlled by slightly changing the molding speed of the two or more outer walls 5 during the production. it can.

  Further, in the honeycomb structure 1 of the present embodiment, the outer wall portion 3 is an inner layer outer wall 8 that is one outer wall 5 disposed so as to cover the cell structure portion 2, and on the outer peripheral surface of the inner layer outer wall 8. It is preferable that it is comprised from the one or more outer-layer outer walls 9 which are the other outer walls 5 laminated | stacked on. As described above, the two or more outer walls 5 stacked in the radial direction of the cell structure portion 2 can be roughly divided into an inner layer outer wall 8 and an outer layer outer wall 9. The inner layer outer wall 8 is directly disposed on the outer periphery of the cell structure portion 2 and dominates a main portion of stress applied to the cell structure portion 2 applied during extrusion molding. Further, the outer layer outer wall 9 is laminated on the outer periphery of the inner layer outer wall 8, and the stress applied to the cell structure portion 2 by the inner layer outer wall 8 is relaxed at the time of extrusion molding.

  In the honeycomb structure 1 of the present embodiment, although not particularly limited, the thickness of the inner layer outer wall 8 constituting the outer wall portion 3 is the same as the thickness of the outer layer outer wall 9 or the thickness of the outer layer outer wall 9. It is also preferable that the thickness of the outer layer outer wall 9 is thinner. Specifically, for example, the thickness of the inner layer outer wall 8 is preferably 0.25 to 1 times the thickness of the outer layer outer wall 9, more preferably 0.3 to 1 times, It is especially preferable that it is -0.6 times. With this configuration, the thickness of the outer wall portion 3 can be easily finely adjusted by the outer layer outer wall 9.

  Further, in the honeycomb structure 1 of the present embodiment, although not particularly limited, the thickness of the inner layer outer wall 8 constituting the outer wall portion 3 is equal to the thickness of the partition wall 4 constituting the cell structure portion 2. It is preferably 0.3 to 4 times, more preferably 0.5 to 3 times, and particularly preferably 1 to 2 times. If the thickness of the inner layer outer wall 8 is less than 0.3 times the thickness of the partition wall 4, the inner layer outer wall 8 is too thin in order to obtain sufficient mechanical strength as the outer wall portion 3. There is a risk that the outer layer outer wall 9 disposed on the outer periphery may be deformed without being able to support the stress. When the thickness of the inner layer outer wall 8 exceeds four times the thickness of the partition wall 4, when the inner layer outer wall 8 is disposed on the outer periphery of the cell structure portion 2, the stress is applied to the cell structure portion 2 due to the stress. Or distortion may occur.

Moreover, although there is no restriction | limiting in particular also about the thickness of the partition 4, For example, it is preferable that it is 30-2000 micrometers, it is more preferable that it is 40-1000 micrometers, and it is especially preferable that it is 50-750 micrometers. Further, the cell density of the cell structure 2 is not particularly limited, but is, for example, 6 to 2000 cells / in ² (0.9 to 311 cells / cm ² ), preferably 50 to 1000 cells / in 2 (7. 8 to 155 cells / cm ² ).

  The cell structure part 2 and the outer wall part 3 are preferably made of a material mainly composed of ceramics and / or metal from the viewpoint of strength, heat resistance, durability, and the like. Examples of the ceramic include cordierite, mullite, alumina, spinel, silicon carbide, silicon nitride, aluminum nitride, zirconia, lithium aluminum silicate, and aluminum titanate. Examples of the metal include Fe-Cr-Al based metals and metals. Silicon etc. can be mentioned, It is preferable that at least 1 sort (s) chosen from these is made into a main component. Furthermore, from the viewpoint of high strength, high heat resistance, etc., it is preferably at least one selected from the group consisting of alumina, mullite, zirconia, silicon carbide and silicon nitride, from the viewpoint of thermal conductivity and heat resistance. Particularly suitable is silicon carbide or a silicon-silicon carbide composite material. Moreover, adsorption materials, such as activated carbon, silica gel, and zeolite, can also be mentioned as suitable materials. Here, the “main component” means that 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more of the cell structure part 2 and the outer wall part 3 is constituted.

  In addition, as shown in FIG. 4, the honeycomb structure 1 of the present embodiment has an opening of a predetermined cell 6 a at one end of the cell structure 2 and an opening of the remaining cell 6 b at the other end. The portion may be sealed with the sealing member 7 and used as a filter. When used as a filter in this way, for example, the exhaust gas containing particulate matter that has flowed in from the end face on one end side of the honeycomb structure 1 passes through the partition wall 4 and the end face on the other end side. However, the porous partition 4 serves as a filter when passing through the partition 4 and can collect particulate matter.

  The sealing member 7 described above may be made of the same material as that of the partition walls 4 constituting the cell structure 2 or may be different, but the functions required for the partition walls 4 and the sealing member 7 are different. Therefore, it is preferable to select a material according to each required function.

  Further, the catalyst may be supported on the surface of the partition wall 4 and / or the pore surface inside the partition wall 4 constituting the cell structure portion 2. For example, when the honeycomb structure 1 is used as a DPF, the pressure loss increases as the collected particulate matter gradually accumulates on the partition walls 4, so that the engine is burdened and fuel consumption and drivability are reduced. Therefore, the particulate matter is periodically burned and removed by a heating means such as a heater to regenerate the filter function. In order to promote combustion during the regeneration, a catalyst is supported on the honeycomb structure 1.

  Further, the catalyst described above preferably has a function of purifying automobile exhaust gas. For example, a metal having catalytic ability, specifically, a noble metal-based perovskite type such as noble metal-based Pt, Pd, Rh, etc. A catalyst etc. can be mentioned as a suitable example.

  The shape of the honeycomb structure 1 of the present embodiment is not particularly limited. For example, the cross-sectional shape of the honeycomb structure 1 may be a circle, an ellipse, a racetrack shape, a quadrangle, etc. Can be determined. Moreover, there is no restriction | limiting in particular in the cross-sectional shape of the cell 6, It is preferable that they are a triangle, a square, and a hexagon.

  Next, an embodiment of a method for manufacturing a honeycomb structure of the present invention (second invention) will be described. The method for manufacturing a honeycomb structure of the present embodiment can be realized using, for example, a honeycomb structure forming apparatus 21 as shown in FIG. The honeycomb structure forming apparatus 21 is for extruding a plate-shaped die 22 having a back hole 24 and a slit 25 and an outer wall portion 3 (see FIG. 1) of the honeycomb structure 1 (see FIG. 1). The outer wall portion forming means 23 is provided. The method for manufacturing a honeycomb structure of the present embodiment includes a cylindrical unfired cell structure portion 12 in which a plurality of cells 6 serving as fluid flow paths are formed by extruding a forming raw material 26, and unfired. A honeycomb formed body 11 composed of an unfired outer wall portion 13 disposed on the outer periphery of the cell structure portion 12 is obtained, and the obtained honeycomb formed body 11 is fired to obtain the honeycomb structure 1 (see FIG. 1). A method for manufacturing a honeycomb structure, wherein a back hole 24 for introducing a predetermined forming raw material 26 into one surface and a forming raw material is formed on one surface, and a slit 25 communicating with the back hole 24 is formed on the other surface. Introduced from the back hole 24 of the plate-shaped base 22, the introduced forming raw material 26 is extruded from the slit 25 of the base 22 to form the unfired cell structure 12, and the remaining forming raw material 26 b On the outer periphery of the structural part 12 The honeycomb molded body 11 is obtained by extruding into two or more hollow cylinders and forming the unfired outer wall portion 13 composed of two or more unfired outer walls 15 laminated in the radial direction of the unfired cell structure portion 12. This is a method for manufacturing a honeycomb structure. By configuring in this way, as shown in FIG. 1, the honeycomb structure 1 constituted by two or more hollow cylindrical outer walls 5 in which the outer wall 3 is laminated in the radial direction of the cell structure 2, It can be manufactured easily and at low cost.

  As shown in FIG. 5, in the method for manufacturing a honeycomb structure of the present embodiment, one unfired one in which the formed unfired outer wall portion 13 is disposed so as to cover the unfired cell structure portion 12. The outer wall 15 is composed of an unfired inner layer outer wall 18 and one or more unfired outer layer outer walls 19 which are other unfired outer walls 15 stacked on the outer peripheral surface of the unfired inner layer outer wall 18. It is preferable.

  Further, in the method for manufacturing a honeycomb structure of the present embodiment, the outer wall forming means 23 described above is disposed on the other surface (surface on the slit 25 side) side of the die 22 to provide two or more concentric annular shapes. It is preferable to form the unfired outer wall portion 13 formed of the two or more unfired outer walls 15 by forming the extrusion ports 27 and extruding the remaining forming raw material 26 b from the two or more extrusion ports 27.

  Specifically, for example, when one unfired outer layer outer wall 19 is extruded and formed on the outer periphery of the unfired inner layer outer wall 18, the outer wall portion forming means 23 has an unfired outer layer outer wall as shown in FIG. One or more forming raw material passage holes 31 through which a part of the remaining forming raw material 26b for forming the outer layer inner peripheral through hole 30 and the unfired outer layer outer wall 19 corresponding to the inner peripheral size of 19 pass are formed. As shown in FIG. 5, the plate-shaped member 28 has a pressing plate 29 in which an outer layer outer peripheral through-hole 32 corresponding to the size of the outer periphery of the unfired outer layer outer wall 19 is formed. In the state where the plate-like member 28 and the pressing plate 29 are separated from each other by a predetermined gap 33 in the extrusion direction of the molding raw material 26, the center of the outer layer inner peripheral through hole 30 and the outer layer outer peripheral through hole 32 is the extrusion of the molding raw material 26. Other than the base 22 so as to be located coaxially in the direction. Is provided on the surface of the base plate, that is, on the surface where the slit 25 is formed, and is formed by a gap 33 a between the base 22 and the plate-like member 28 and a gap 33 b between the plate-like member 28 and the holding plate 29. It is preferable that the unfired inner layer outer wall 18 and the unfired outer layer outer wall 19 are extruded and molded from the two concentric annular extrusion ports 27 formed.

  With this configuration, the forming raw material 26b that has passed through the gap 33a between the die 22 and the plate-like member 28 is passed through the outer circumference of the outer layer on the outer circumference of the unfired cell structure 12 extruded from the slit 25 of the die 22. Extruded from the hole 30 to form the unfired inner layer outer wall 18, and the forming raw material 26 b that has passed through the gap 33 b between the plate-like member 28 and the pressing plate 29 is extruded onto the outer periphery of the unfired inner layer outer wall 18. The outer wall 19 can be easily formed. In the gap 33a between the base 22 and the plate-like member 28 and the gap 33b between the plate-like member 28 and the holding plate 29, a spacer 34 having a predetermined thickness is provided to form the above-described gaps 33a and 33b. It is preferable to do.

  As the base 22 shown in FIG. 5, a base conventionally used for manufacturing a honeycomb structure can be used as it is. Therefore, by arranging the outer wall forming means 23 described above in a conventionally known base, FIG. Can be configured, and the honeycomb structure manufacturing method of the present embodiment can be performed using the honeycomb structure forming apparatus 21. Further, the outer wall portion forming means 23 shown in FIG. 5 can be replaced with various types of bases, so that the number of bases 22 can be reduced, and the honeycomb structure can be manufactured at low cost. Can be manufactured.

  FIG. 5 shows an example in which the surface of the base 22 on which the slit 25 is formed is flat. For example, as shown in FIG. 8, the inner portion for extruding the unfired cell structure portion 12. May be a base 22 protruding in a tapered shape. The taper angle at which the inner portion of the base 22 protrudes is preferably 0 to 90 °. In FIG. 8, the same components as those shown in FIG. 5 are denoted by the same reference numerals, and description thereof is omitted.

  The size of the outer-layer inner peripheral through-hole 30 formed in the plate-shaped member 28 may be a size corresponding to the size of the outer periphery of the unfired inner-layer outer wall 18 when the number of the plate-shaped members 28 is one. Specifically, it is preferable that the size of the outer layer outer peripheral through-hole 32 is 1 to 50 mm larger than the size of the inner periphery of the unfired outer layer outer wall 19 or the size of the outer periphery of the unfired inner layer outer wall 18.

  FIG. 5 shows an example in which the inner peripheral surface forming the outer-layer inner peripheral through-hole 30 of the plate-like member 28 is parallel to the extrusion direction of the molding raw material 26. For example, the extrusion direction of the molding raw material 26 is shown. It may be formed in a taper shape with respect to 0 to 60 °. That is, it is preferable that the angle A formed by the surface of the plate-like member 28 on the side facing the base 22 and the inner peripheral surface forming the outer-layer inner peripheral through hole 30 is 90 to 150 °. Further, the above-described corner A may have a curvature, and the corner A may be chamfered with a predetermined length. When the corner A has a curvature, the radius of curvature is preferably 1 mm or less, and when the corner A is chamfered, the length of the C surface is preferably 0.05 to 1 mm.

  In addition, the surface of the plate-like member 28 facing the pressing plate 29 in the vicinity of the outer layer inner peripheral through-hole 30 is a part of the passage and the extrusion port 27 for extruding the unfired outer layer outer wall 19. The surface may be inclined so that the unfired outer layer outer wall 19 is in close contact with the outer peripheral surface of the unfired inner layer outer wall 18 while appropriately pressing the unfired inner layer outer wall 18. Specifically, the angle B formed by the surface facing the pressing plate 29 in the vicinity of the outer layer inner peripheral through-hole 30 of the plate-like member 28 and the inner peripheral surface forming the outer layer inner peripheral through-hole 30 is 30. It is preferable to be configured to be ~ 90 °. By configuring in this manner, the unfired outer layer outer wall 19 is 30 to 90 with respect to the outer peripheral surface of the unfired inner layer outer wall 18 from the extrusion port 27 formed in the gap 33b between the plate-like member 28 and the pressing plate 29. It becomes possible to extrude and form so as to contact at an angle of °, and the adhesion between the unfired inner layer outer wall 18 and the unfired outer layer outer wall 19 can be improved. Further, the corner B described above may have a curvature, and the corner B may be chamfered with a predetermined length. When the corner B has a curvature, the radius of curvature is preferably 0.1 to 5 mm, and when chamfering is performed, the length of the C surface is preferably 0.1 to 5 mm.

  With respect to one or more forming raw material passage holes 31 formed in the plate-like member 28, a part of the remaining forming raw material 26b for forming the unfired outer layer outer wall 19 passes from the base 22 side to the holding plate 29 side. As long as it becomes a passage for the purpose, there is no particular limitation on the shape and the like, but for example, when manufacturing a honeycomb structure used for a DPF for automobiles, the forming raw material passage hole 31 is, About 1-1000 pieces are preferably formed on the outer side of the outer peripheral inner circumferential through-hole 30, and the size of the opening diameter of the forming raw material passage hole 31 is preferably 0.5 to 10 mm. Further, when there are two or more forming raw material passage holes 31, it is preferably formed in a state of being arranged radially or in a lattice shape outside the inner peripheral through hole 30 of the outer layer.

  The thickness of the plate member 28 is not particularly limited, but is preferably 0.1 mm or more. By comprising in this way, the shaping | molding precision of the unbaking outer wall part 13 can be improved.

  The gap 33a between the plate-like member 28 and the base 22 serves as a passage through which the forming raw material 26b for forming the unfired inner layer outer wall 18 passes, so that a necessary and sufficient amount of the forming raw material 26 is supplied and the unfired cell structure portion It is preferable to form at intervals that can be extruded according to the molding speed of 12. Specifically, the gap 33a between the plate-like member 28 and the base 22 is preferably 1 to 4 times the thickness of the unfired inner layer outer wall 18 to be molded. In order to form such a gap 33 a, it is preferable to adjust the gap 33 a by arranging the spacer 34 having the above-described thickness between the plate-like member 28 and the base 22. Such a spacer 34 can be prevented from flowing out of the forming raw material 16 from the outside of the plate member 28 by forming an annular shape so as to surround the outside of the plate member 28.

  The pressing plate 29 constituting the outer wall portion forming means 23 is formed with an outer layer outer peripheral through hole 32 corresponding to the outer peripheral size of the unfired outer layer outer wall 19. The specific size of the outer layer outer peripheral through hole 32 varies depending on the size of the outer layer outer wall to be molded. For example, the outer layer outer peripheral through hole 32 may be formed larger by about 0.5 to 50 mm than the outer layer inner peripheral through hole 30. preferable.

  The vicinity of the outer layer outer peripheral through-hole 32 of the presser plate 29 is in the form along the shape of the corner B formed by the surface of the plate-shaped member 28 and the inner peripheral surface forming the outer layer inner peripheral through-hole 30 described above. It is preferable that the interval, that is, the width of the extrusion port 27 for extruding the unfired outer layer outer wall 19 is about 0.05 to 5 mm. In addition, as shown in FIG. 5, when the outer layer outer peripheral through-hole 32 is configured to become wider in the extrusion direction, the stress applied to the honeycomb formed body 11 is released, and the forming accuracy is improved. Can do. Although not shown, the outer layer outer peripheral through hole may be configured to become narrower in the extrusion direction. In this case, the adhesion of each outer wall constituting the outer wall portion is improved. Can do.

  As shown in FIG. 5, the gap 33b between the plate-like member 28 and the pressing plate 29 serves as a passage through which the molding raw material 26 for molding the unfired outer layer outer wall 19 passes. It is preferably formed so as to be able to match the forming speed of the unfired inner layer outer wall 18 that is supplied and extruded at the same time. Specifically, it is preferably 0.025 to 1 mm. By changing the angle B formed by the gap 33b between the plate-like member 28 and the pressing plate 29, and the surface of the plate-like member 28 and the inner peripheral surface forming the outer-layer inner peripheral through hole 30, the above-mentioned The width of the extrusion port 27 through which the fired outer layer outer wall 19 is extruded can be changed.

  Further, as shown in FIGS. 9A and 9B, the presser plate 29 has an annular groove 35 formed on the surface side facing the plate-like member 28 (see FIG. 5). Also good. Since the forming raw material 26 (see FIG. 5) can be stored in the groove portion 35, the amount of the forming raw material 26 (see FIG. 5) extruded from the inner peripheral through hole 30 can be increased. A stable amount of extrusion can be achieved. Further, as shown in FIGS. 10A and 10B, an annular groove 35 is formed on the surface side facing the plate-like member 28 (see FIG. 5), and a molding raw material 26 to be extruded (see FIG. 10). 5 may be provided with a screw 36 for adjusting the amount. By comprising in this way, not only the quantity of the shaping | molding raw material 26 extruded from the outer peripheral inner periphery through-hole 30 can be increased but the quantity of the shaping | molding raw material 26 extruded can be adjusted. Further, in the method for manufacturing a honeycomb structured body of the present embodiment, as shown in FIG. 11, the forming raw material 26 may be introduced from the outer peripheral side of the pressing plate 29 to form the unfired outer layer outer wall 19. In this case, as shown in FIGS. 12A and 12B, an annular first groove portion 37 is formed on the surface side facing the plate-like member 28 (see FIG. 5), and The second groove 38 may be formed radially from the first groove 37 toward the outer peripheral side. With this configuration, it is possible to introduce a sufficient amount of the forming raw material 26 from the second groove portion 38, and to store the introduced forming raw material 26 in the first groove portion 37. It is possible to further increase the amount of the forming raw material 26 extruded from 30. In FIG. 11, the same components as those shown in FIG. 5 are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 5, the size of the outer periphery of the base 22 is substantially the same as the size of the outer periphery of the plate-like member 28 and the pressing plate 29 constituting the outer wall portion forming means 23. For example, as shown in FIG. In addition, on the outer peripheral side of the base 22, without forming the slit 25, the back hole 24 can be penetrated from one surface of the base 22 to the other surface, and the forming raw material 26 b can be directly introduced from the back hole 24. You may be able to do it. Further, as shown in FIG. 14, the size of the outer periphery of the base 22 is made smaller than the sizes of the outer periphery of the plate-like member 28 and the holding plate 29, and corresponds to the outer circumference of the plate-like member 28 and the holding plate 29. The cylindrical outer frame 55 is disposed so that the forming raw material 26b can be directly introduced into the gap 33b between the plate-like member 28 and the pressing plate 29 by passing through the outside of the base 22. Good. By comprising in this way, the introduction amount of the shaping | molding raw material 26b which comprises the unbaking outer wall part 13 can be increased.

  In the method for manufacturing a honeycomb structure according to the present embodiment, at least one of the two or more unfired outer walls 15 is different from a predetermined material for forming the unfired cell structure portion 12. Extrusion molding may be performed using molding raw materials of various types. For example, a silica-rich molding raw material is used as at least a part of the molding raw material 26b for molding two or more unfired outer walls 15 and extruded from a different flow path from the other molding raw materials 127. At least one unfired outer wall 5 is formed. With this configuration, when the outer wall 5 (see FIG. 1) is water-resistant and a liquid is used as a fluid that passes through the cell 6 (see FIG. 1), the liquid is transferred to the outer wall 5 (see FIG. 1). ) To the outside of the honeycomb structure 1 (see FIG. 1) can be effectively prevented.

In the method for manufacturing a honeycomb structured body of the present embodiment, it is preferable to control the orientation of the unfired outer layer outer wall 19 when the unfired outer layer outer wall 19 is formed, and to form the unfired outer layer outer wall 19. it is also preferable to control the gap between the forming material together and forming a gap between the forming raw material for molding the raw material and the green lining the outer wall 18, and / or two or more unsintered outer exterior wall 19. As a specific method, there can be mentioned a method of controlling the orientation and the respective gaps by varying the extrusion speed of the molding material.

  Further, in the method for manufacturing a honeycomb structured body of the present embodiment, the plate-like member 28 and the pressing plate 29 to be used can be detached from the base 22, and the plate-like member 28 and / or the pressing plate 29 are placed inside the outer layer. Replace with another plate-like member (not shown) having a different shape of the peripheral through-hole 30 and / or another pressing plate (not shown) having a different shape of the outer-layer outer peripheral through-hole 32, and a non-fired outer wall portion having a different shape 13 can be molded. Thus, since the plate-like member 28 and / or the pressing plate 29 can be exchanged, honeycomb structures of various sizes can be easily manufactured. In addition, since the unfired outer wall portion 13 does not flow into the unfired cell structure portion 12, the honeycomb structure can be favorably maintained.

  Further, in the method for manufacturing a honeycomb structure according to the present embodiment, for example, two or more unfired green bodies are formed on the outer peripheral side of the unfired inner layer outer wall 18 using a honeycomb structure forming apparatus 41 as shown in FIG. The outer layer outer wall 19 may be extruded. Specifically, in the case where two or more unfired outer layer outer walls 19 are extruded on the outer peripheral side of the unfired inner layer outer wall 18, the outer wall portion forming means 43 has the size of the inner periphery of the unfired outer layer outer wall 19. Two or more plate-like members formed with one or more forming raw material passage holes 51 through which a part of the remaining forming raw material 26b for forming the corresponding outer layer inner peripheral through hole 50 and the unfired outer layer outer wall 19 pass. 48 and a pressing plate 49 in which an outer layer outer peripheral through hole 52 corresponding to the outer peripheral size of the outermost unfired outer layer outer wall 19a among the two or more unfired outer layer outer walls 19 is formed. The plate-shaped member 48 and the pressing plate 49 are separated from each other by a predetermined gap 53 in the extrusion direction of the forming raw material 26, and the center of the outer layer inner peripheral through hole 50 and the outer layer outer peripheral through hole 52 is the center of the forming raw material 26. The base 22 is positioned so as to be coaxial with the extrusion direction. The slit 25 is disposed on the other surface side, and the gap 53a between the base 22 and the plate member 48, the gap 53c between adjacent plate members, and the plate member 48 and the pressing plate. Preferably, the unfired inner layer outer wall 18 and the two or more unfired outer layer outer walls 19 are extruded and molded from three or more concentric annular extrusion ports 47 formed by the gaps 53b with respect to 49. 13 to 15, the same components as those shown in FIG. 5 are denoted by the same reference numerals and description thereof is omitted.

  With such a configuration, the forming raw material 26 introduced from the back hole 44 is extruded from the slit to form the unfired cell structure portion 12, and at the same time, on the outer periphery of the formed unfired cell structure portion 12 Three or more unfired outer walls can be extruded and laminated from one or more extrusion ports 47. In the honeycomb structure forming apparatus 41 shown in FIG. 15, the outer wall forming means 43 has two or more plate-like members 48, and each plate-like member 48 has an inner periphery of the unfired outer layer outer wall 19. The outer layer inner peripheral through-hole 50 corresponding to the size is formed, and corresponds to the inner peripheral size of the unfired outer wall portion 13 to be disposed on the inner side on the slit side surface of the base 22. 5 is substantially the same as the honeycomb structure forming apparatus 21 shown in FIG. 5 except that the outer layer inner peripheral through-holes 50 are arranged in order from the plate-like member 48 with a predetermined gap 53 therebetween. It can be set as this structure. In the honeycomb structure forming apparatus 41 shown in FIG. 15, the plate member 48 does not have to be inclined in the vicinity of the outer peripheral inner circumferential through hole 50, and each plate member 48 has a flat plate shape. It is preferable.

  As shown in FIG. 5, a honeycomb structure forming apparatus 21 used in the method for manufacturing a honeycomb structure of the present embodiment includes a plate-shaped die 22 having a back hole 24 and a slit 25, and outer wall forming. In addition to the means 23, an extruder (not shown) having a piston and a cylinder for extruding the forming raw material 26 from the back hole 24 side of the die 22 and a backing plate (not shown). ) Etc. may be provided. By using such a honeycomb structure forming apparatus 21, the honeycomb structure 1 as shown in FIG. 1 can be continuously extruded and the honeycomb structure 1 can be manufactured with high efficiency. .

  In the method for manufacturing a honeycomb structured body of the present embodiment, the step of firing the honeycomb formed body performed after obtaining the honeycomb formed body by the above-described method is performed by the conventional method for manufacturing a honeycomb structured body. A known firing method can be preferably used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to a following example.

Example 1
It is composed of a cylindrical cell structure part in which a plurality of cells serving as fluid flow paths are defined by a porous partition wall, and two or more hollow cylindrical outer walls stacked in the radial direction of the cell structure part A honeycomb structure (Example 1) having an outer wall portion is formed using a honeycomb structure forming apparatus 21 as shown in FIG. 5 using ceramics mainly composed of alumina, kaolin, and talc as a forming raw material. 100 were manufactured.

  The outer wall portion of the honeycomb structure of the present example is an inner layer outer wall that is one outer wall disposed so as to cover the cell structure portion, and an outer layer outer wall that is another outer wall laminated on the outer peripheral surface of the inner layer outer wall. The inner layer outer wall has a thickness of 0.1 mm, and the outer layer outer wall has a thickness of 0.3 mm.

  The 100 honeycomb structures were inspected for cell shape defects, and the number of honeycomb structures that passed the inspection was measured. As a method for inspecting the defective shape of the cell, a cross section of the honeycomb structure cut with a camera is photographed, and a deviation amount of the cell with respect to a normal lattice structure (honeycomb structure) is determined by image processing. As the inspection standard, for each cell, when the deviation from the grid reference is less than 0.1 mm, it is indicated as ◯, and when the deviation from the grid reference is 0.1 to 0.2 mm, it is indicated as Δ. When the deviation | shift amount from a reference | standard exceeds 0.2 mm, it was set as x.

  Further, the isostatic strength of each honeycomb structure was measured. In addition, regarding the measured value, the maximum value was set to 10 MPa every 0 MPa to 1 MPa. As a method for measuring the isostatic strength, the strength was evaluated when the honeycomb structure was compressed under hydrostatic pressure and the cell was damaged based on JASO standard M505-87. FIG. 16 is a graph showing the relationship between the isostatic strength of the honeycomb structure of the present example and the number of breaks at the time of measuring the isostatic strength at each outer wall thickness. The horizontal axis represents the isostatic strength (MPa) of the honeycomb structure, and the vertical axis represents the number of breakage (pieces) at the time of isostatic strength measurement. The number of breakage at the time of isostatic strength measurement indicates the number of cells in which breakage of the cell is confirmed from the cross section of the honeycomb structure.

(Comparative Examples 1 and 2)
A honeycomb structure comprising a cylindrical cell structure portion in which a plurality of cells serving as fluid flow paths are defined by porous partition walls, and a single outer wall portion disposed on the outer periphery of the cell structure portion ( One hundred comparative examples 1 and 2) were produced. As the forming raw material, ceramic was used as in the honeycomb structure of Example 1, the thickness of the outer wall of the honeycomb structure of Comparative Example 1 was 0.1 mm, and the thickness of the outer wall of the honeycomb structure of Comparative Example 2 was 0.3 mm.

  For the honeycomb structures of Comparative Examples 1 and 2, the cell shape inspection and isostatic strength measurement were performed in the same manner as in Example 1. The results are shown in the graph shown in FIG.

  In the graph shown in FIG. 16, the more the distribution of the graph is on the right, the higher the isostatic strength, and the honeycomb structure of the present example has higher isostatic strength than Comparative Examples 1 and 2. Is shown. In particular, the thickness of the outer wall portion of the honeycomb structure of Example 1 (the total thickness of the inner layer outer wall and the outer layer outer wall) is the same as the thickness of the outer layer portion of the honeycomb structure of Comparative Example 2. It can be seen that the isostatic strength is improved by using two or more outer walls (inner layer outer wall and outer layer outer wall).

(Examples 2 to 4)
A cylindrical cell structure part in which a plurality of cells serving as fluid flow paths are defined by a porous partition wall, and two or more hollow cylindrical outer walls (inner layer outer wall and Honeycomb structures (Examples 2 to 4) provided with an outer wall portion composed of an outer layer outer wall) were manufactured using ceramics as a forming raw material. The honeycomb structure of Example 2 has an inner layer outer wall thickness of 0.1 m and the outer layer outer wall thickness of 0.1 mm. The honeycomb structure of Example 3 has an inner layer outer wall thickness of 0.1 mm. The thickness of the outer layer outer wall is 0.2 mm, and the honeycomb structure of Example 4 has the inner layer outer wall thickness of 0.1 mm and the outer layer outer wall thickness of 0.5 mm.

  In the honeycomb structures of Examples 2 to 4, cell shape defects were inspected by the same method as in Example 1. The results are shown in Table 1. In addition, the outer wall shape was also inspected for defects. As a method for inspecting the shape of the outer wall, the outer wall was visually checked for appearance defects such as turning, wrinkles, and cuts. The inspection standard is ○ when the appearance defect is not confirmed, △ when several defects are confirmed, and × when there are many cuts and wrinkles with no uniform outer wall. It was. The results are shown in Table 1.

(Comparative Examples 3-5)
A honeycomb structure comprising a cylindrical cell structure portion in which a plurality of cells serving as fluid flow paths are defined by porous partition walls, and a single outer wall portion disposed on the outer periphery of the cell structure portion ( Comparative Examples 3 to 5) were produced. As the forming raw material, ceramic was used as in the honeycomb structure of Example 1, the thickness of the outer wall of the honeycomb structure of Comparative Example 3 was 0.1 mm, and the thickness of the outer wall of the honeycomb structure of Comparative Example 4 was The thickness of the outer wall of the honeycomb structure of Comparative Example 5 was set to 0.3 mm.

  With respect to the honeycomb structures of Comparative Examples 3 to 5, the cell shape defect inspection and the outer wall shape defect inspection were performed in the same manner as in Example 2. The results are shown in Table 1.

  As shown in Table 1, in the honeycomb structures of Examples 2 to 4, even when the thickness of the outer wall portion (the sum of the thickness of the inner layer outer wall and the thickness of the outer layer outer wall) is increased, cell forming defects are caused. It is difficult to see that the isostatic strength is excellent. In addition, the honeycomb structure of Comparative Example 3 showed good results in both the cell molding defect and the outer wall shape defect inspection, but as can be seen from the graph shown in FIG. Since the thickness was thin, the isostatic strength was low, and it was easily damaged.

  The honeycomb structure of the present invention has excellent mechanical strength of the outer wall portion, and molding defects such as twisting and distortion of the partition walls are effectively prevented. For example, a collection filter for removing particulate matter It can also be suitably used as a catalyst carrier. In addition, the honeycomb structure manufacturing method of the present invention can manufacture such a honeycomb structure easily and at low cost.

1 is a perspective view schematically showing one embodiment of a honeycomb structure of the present invention (first invention). Fig. 2 is a plan view schematically showing one end face of the honeycomb structure shown in Fig. 1. Fig. 5 is a plan view schematically showing one end face in another embodiment of the honeycomb structure of the present invention (first invention). It is a perspective view which shows typically the honeycomb structure by which the opening part of the cell was sealed with the sealing member. It is sectional drawing which shows an example of the honeycomb structure shaping | molding apparatus used for the manufacturing method of the honeycomb structure of this invention (2nd invention). FIG. 6 is a plan view showing a plate member used in the honeycomb structure forming apparatus shown in FIG. 5. Fig. 6 is a plan view showing a pressing plate used in the honeycomb structure forming apparatus shown in Fig. 5. FIG. 6 is a cross-sectional view showing another example of a honeycomb structure forming apparatus used in the method for manufacturing a honeycomb structure of the present invention (second invention). FIG. 9 (a) is a plan view schematically showing an example of a pressing plate used in the honeycomb structure forming apparatus shown in FIG. 5, and FIG. 9 (b) is a pressing plate shown in FIG. 9 (a). It is sectional drawing cut | disconnected by DD line. Fig. 10 (a) is a plan view schematically showing another example of the pressing plate used in the honeycomb structure forming apparatus shown in Fig. 5, and Fig. 10 (b) is shown in Fig. 10 (a). It is sectional drawing which cut | disconnected the pressing plate with the EE line | wire. It is sectional drawing which shows typically the method of introduce | transducing a shaping | molding raw material into the outer wall part shaping | molding means in the manufacturing method of the honeycomb structure of this invention (2nd invention). Fig. 12 (a) is a plan view schematically showing another example of a pressing plate used in the honeycomb structure forming apparatus shown in Fig. 5, and Fig. 12 (b) is shown in Fig. 12 (a). It is sectional drawing which cut | disconnected the pressing plate by the FF line. FIG. 6 is a cross-sectional view showing another example of a honeycomb structure forming apparatus used in the method for manufacturing a honeycomb structure of the present invention (second invention). FIG. 6 is a cross-sectional view showing another example of a honeycomb structure forming apparatus used in the method for manufacturing a honeycomb structure of the present invention (second invention). FIG. 6 is a cross-sectional view showing another example of a honeycomb structure forming apparatus used in the method for manufacturing a honeycomb structure of the present invention (second invention). It is a graph which shows the relationship between the isostatic strength of a honeycomb structure in a present Example, and the number of breakage at the time of isostatic strength measurement in the thickness of each outer wall. Fig. 17 (a) is a perspective view schematically showing a conventional honeycomb structure, and Fig. 17 (b) is a plan view schematically showing one end face of the honeycomb structure of Fig. 17 (a). is there. FIG. 5 is a vertical sectional view schematically showing a honeycomb structure forming apparatus used when manufacturing a conventional honeycomb structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Honeycomb structure, 2 ... Cell structure part, 3 ... Outer wall part, 4 ... Partition wall, 5 ... Outer wall, 6, 6a, 6b ... Cell, 7 ... Sealing member, 8 ... Inner layer outer wall, 9 ... Outer layer outer wall, 11 DESCRIPTION OF SYMBOLS ... Honeycomb forming body, 12 ... Unsintered cell structure part, 13 ... Unsintered outer wall part, 15 ... Unsintered outer wall, 18 ... Unsintered inner layer outer wall, 19 ... Unsintered outer layer outer wall, 19a ... Unsintered outer layer outer wall, DESCRIPTION OF SYMBOLS 21 ... Honeycomb structure shaping | molding apparatus, 22 ... Base, 23 ... Outer wall part shaping | molding means, 24 ... Back hole, 25 ... Slit, 26, 26a, 26b ... Molding raw material, 27 ... Extrusion port, 28 ... Plate-shaped member, 29 ... Presser plate, 30 ... outer layer inner peripheral through hole, 31 ... molding raw material passage hole, 32 ... outer layer outer peripheral through hole, 33, 33a, 33b ... gap, 34 ... spacer, 35 ... groove, 36 ... screw, 37 ... first Groove part, 38 ... second groove part, 41 ... honeycomb structure forming apparatus, 43 Outer wall portion forming means, 47: extrusion port, 48: plate-like member, 49: pressing plate, 50 ... outer layer inner peripheral through hole, 51 ... molding raw material passage hole, 52 ... outer layer outer peripheral through hole, 53, 53a, 53b, 53c ... Gap, 55 ... Outer frame, 61 ... Honeycomb structure, 62 ... Outer wall, 63 ... Cell, 64 ... Partition wall, 70 ... Honeycomb structure forming apparatus, 72, 83, 84 ... Slit, 73 ... Back hole, 74 ... Base 75 ... Presser plate, 77 ... Gap, 78 ... Presser member, 79 ... Back presser plate, 82 ... Honeycomb molded body, 126,127 ... Forming raw material, A, B ... Square.

Claims (19)

A honeycomb structure including a cylindrical cell structure portion in which a plurality of cells serving as fluid flow paths are defined by porous partition walls, and an outer wall portion disposed on the outer periphery of the cell structure portion. And
A honeycomb structure in which the outer wall portion is composed of two or more hollow cylindrical outer walls laminated in the radial direction of the cell structure portion.   The honeycomb structure according to claim 1, wherein each of the outer walls constituting the outer wall portion is integrally fired.   The outer wall portion is an inner layer outer wall that is one outer wall disposed so as to cover the cell structure portion, and one or more outer layers that are other outer walls stacked on the outer peripheral surface of the inner layer outer wall. The honeycomb structure according to claim 1 or 2, comprising an outer wall.   The honeycomb structure according to claim 3, wherein a thickness of the inner layer outer wall constituting the outer wall portion is thinner than a thickness of the outer layer outer wall.   The honeycomb structure according to claim 3 or 4, wherein a thickness of the inner layer outer wall constituting the outer wall portion is 0.3 to 4 times a thickness of the partition wall constituting the cell structure portion.   The honeycomb structure according to any one of claims 1 to 5, wherein the cell structure part and the outer wall part are made of a material mainly composed of ceramics and / or metal.   The at least one said outer wall of the said 2 or more said outer walls which comprise the said outer wall part was comprised in the kind of material different from the material which comprises the said cell structure part in any one of Claims 1-6. Honeycomb structure.   A predetermined opening of the cell at one end of the tubular cell structure and a remaining opening of the cell at the other end are sealed by a sealing member and used as a filter. Item 8. The honeycomb structure according to any one of Items 1 to 7.   The honeycomb structure according to any one of claims 1 to 8, wherein a catalyst is supported on a surface of the partition wall and / or a pore surface inside the partition wall constituting the cell structure portion.   The honeycomb structure according to claim 9, wherein the catalyst has a function of purifying automobile exhaust gas. A cylindrical unfired cell structure part formed by extruding a forming raw material and partitioning a plurality of cells serving as fluid flow paths by partition walls, and an unfired outer wall disposed on the outer periphery of the unfired cell structure part A honeycomb structure manufacturing method for obtaining a honeycomb formed body comprising a portion and firing the obtained honeycomb formed body to obtain a honeycomb structure,
At least a predetermined forming raw material is introduced from the back hole of the plate-shaped die in which a back hole for introducing the forming raw material is formed on one surface and a slit communicating with the back hole is formed on the other surface And extruding the introduced predetermined forming raw material from the slit of the die to form the unfired cell structure part, and the remaining forming raw material to two or more on the outer periphery of the unfired cell structure part A honeycomb structure obtained by extruding into a hollow cylindrical shape and forming the unfired outer wall portion composed of two or more unfired outer walls laminated in the radial direction of the unfired cell structure portion to obtain the honeycomb formed body Manufacturing method.   The unfired outer wall portion is laminated on the unfired inner layer outer wall which is the unfired outer wall disposed so as to cover the unfired cell structure portion, and the outer peripheral surface of the unfired inner layer outer wall. The method for manufacturing a honeycomb structured body according to claim 11, comprising one or more unfired outer layer outer walls which are the unfired outer walls.   The at least one unfired outer wall of the two or more unfired outer walls is extruded using a forming raw material of a material different from the predetermined material for forming the unfired cell structure. Or the manufacturing method of the honeycomb structure of 12.   On the other surface side of the die, outer wall forming means is disposed so as to form two or more concentric annular extrusion ports, and the remaining molding raw material is extruded from two or more of the extrusion ports, The method for manufacturing a honeycomb structured body according to any one of claims 11 to 13, wherein the green outer wall portion is formed. When forming the unfired outer layer outer wall , a gap between the forming raw material for forming the unfired outer layer outer wall and the forming raw material for forming the unfired inner layer outer wall, and / or two or more unfired outer layer outer walls The method for manufacturing a honeycomb structure according to any one of claims 12 to 14 , wherein a gap between the forming raw materials for forming the material is controlled. On the outer periphery of the unfired inner layer outer wall, when one of the unfired outer layer outer walls is extruded and molded,
The outer wall forming means is formed with an outer layer inner peripheral through hole corresponding to the inner peripheral size of the unfired outer layer outer wall and one or more molding raw material passage holes through which a part of the remaining molding raw material passes. A plate-shaped member and a pressing plate in which an outer layer outer peripheral through-hole corresponding to the size of the outer periphery of the unfired outer layer outer wall is formed, and the plate-shaped member and the pressing plate are in the extrusion direction of the forming raw material And the other surface side of the die so that the center of the outer layer inner peripheral through hole and the outer layer outer peripheral through hole are located on the same axis in the extrusion direction of the forming raw material. It is arranged in the
The unfired inner layer outer wall and the unfired outer layer outer wall are extruded from two concentric annular extrusion ports formed by a gap between the base and the plate-like member and a gap between the plate-like member and the pressing plate. The method for manufacturing a honeycomb structure according to claim 14 or 15 , wherein the honeycomb structure is formed by molding. In the case of extruding two or more unfired outer layer outer walls on the outer peripheral side of the unfired inner layer outer wall,
The outer wall forming means is formed with an outer layer inner peripheral through hole corresponding to the inner peripheral size of the unfired outer layer outer wall and one or more molding raw material passage holes through which a part of the remaining molding raw material passes. Two or more plate-shaped members, and a pressing plate in which an outer layer outer peripheral through-hole corresponding to the outer peripheral size of the outermost outer wall of the non-fired outer layer is formed among the two or more unfired outer layer outer walls. The two or more plate-like members and the pressing plate are separated from each other by a predetermined gap in the extrusion direction of the forming raw material, and the center of the outer layer inner peripheral through hole and the outer layer outer peripheral through hole is the center. It is disposed on the other surface side of the base so as to be positioned on the same axis in the extrusion direction of the forming raw material,
From the three or more concentric annular extrusion ports formed by the gap between the base and the plate member, the gap between the adjacent plate members, and the gap between the plate member and the pressing plate The method for manufacturing a honeycomb structured body according to claim 14 or 15 , wherein a fired inner layer outer wall and two or more of the unfired outer layer outer walls are formed by extrusion. The unfired outer layer outer wall constituting the unfired outer wall portion is extruded and molded so as to be in contact with an outer peripheral surface of the unfired inner layer outer wall constituting the unfired outer wall portion at an angle of 30 to 90 °. Item 18. A method for manufacturing a honeycomb structure according to any one of Items 12 to 17 . The plate-like member and the presser plate are removable from the base, and the plate-like member and / or the presser plate is replaced with another plate-like member and / or the outer layer having a different shape of the outer peripheral inner peripheral through hole. 19. The method for manufacturing a honeycomb structured body according to any one of claims 11 to 18 , wherein the unfired outer wall portion having a different shape can be formed by exchanging with another pressing plate having a different shape of the outer peripheral through hole.

Images