JP4975426B2 - Die for forming honeycomb structure - Google Patents

Description

  The present invention relates to a die for forming a honeycomb structure, and more particularly, to a die for forming a honeycomb structure having excellent formability and wear resistance of the honeycomb structure.

  As a method for manufacturing a ceramic honeycomb structure, conventionally, a die for forming a honeycomb structure in which a back hole for introducing a forming raw material (kneaded material) and a grid-like slit communicating with the back hole is formed. The method of using and extruding is widely used. This base usually has an introduction part formed by opening a plurality of back holes with a large area on one surface (introduction surface) side, and a honeycomb structure on the opposite surface (the other surface). A slit having a width corresponding to the partition wall thickness of the body is formed in a lattice shape or the like. And a back hole is normally provided corresponding to the position where slits, such as a grid | lattice shape, cross | intersect, and both are communicating inside a nozzle | cap | die. Therefore, the forming raw material such as the ceramic raw material introduced from the back hole moves from the back hole having a relatively large inner diameter to a narrow slit, and is extruded from the opening of the slit as a formed body of the honeycomb structure. .

As such a die for forming a honeycomb structure, for example, a plate-like member made of one kind of alloy such as a stainless alloy or a cemented carbide, or two different kinds of plate-like members are joined. A plate-like member is used (see, for example, Patent Documents 1 to 3).
JP 2000-326318 A JP 2003-285308 A Japanese Patent Laid-Open No. 10-315213

  However, the die for forming a honeycomb structure has irregularities on the introduction surface, and variations in the irregularities on the introduction surface result in variations in the fluidity of the clay, thereby causing the moldability, particularly the outer wall. There was a problem with the moldability of the. In addition, the uneven shape has changed due to wear, and there has also been a problem that the variation in fluidity has also changed.

  The present invention has been made in view of the above-described problems, and is characterized by providing a die for forming a honeycomb structure excellent in formability and wear resistance of the honeycomb structure during extrusion molding.

  In order to achieve the above object, the present invention provides the following die for forming a honeycomb structure.

[1] A plate having an introduction portion provided on one surface (surface on the introduction side) and having a plurality of back holes, and a molding portion provided on the other surface side and formed with slits communicating with the back holes. A plate-shaped die for forming a honeycomb structure, in which a forming raw material introduced from a back hole of the introduction part is formed into a honeycomb shape through a slit of the formation part, the back of the introduction part A back plate having a plurality of flow holes communicating with the holes is detachably disposed on the introduction side surface, and only the back plate has a diamond-like carbon film (DLC film) on the surface thereof. The DLC film is disposed at least on the surface of the back plate on which the forming raw material is introduced, and the flow hole of the back plate and the back hole of the introduction part have the same hole diameter, Distribution of plates A die for forming a honeycomb structure in which a hole and a back hole of the introduction portion are overlapped without being shifted.

[2] The honeycomb structure forming die according to [1], wherein the DLC film has a thickness of 0.01 to 10 μm.

[ 3 ] The die for forming a honeycomb structure according to [1] or [2] , wherein the plurality of flow holes formed in the back plate all have substantially the same hole diameter.

[ 4 ] The honeycomb structure forming die according to any one of [1] to [ 3 ], wherein the back plate is detachably disposed on the introduction portion by bolting or pin fitting.

  According to the honeycomb structure forming die of the present invention, the back plate in which the flow hole communicating with the back hole of the introduction portion is formed is detachably disposed on the introduction side surface, and the back plate is formed on the surface thereof. In addition, since it has a diamond-like carbon film (DLC film), it is possible to suppress variations in fluidity of the forming raw material due to the high smoothness of the DLC film disposed on the back plate. Further, the back plate can be used over a long period of time due to the high wear resistance of the DLC film. Furthermore, since the back plate is detachably disposed on the base body, one back plate can be used for a plurality of bases.

  Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the following embodiment and does not depart from the spirit of the present invention. Therefore, it should be understood that design changes, improvements, and the like can be made as appropriate based on ordinary knowledge of those skilled in the art.

  FIG. 1 is a cross-sectional view schematically showing an embodiment of a die for forming a honeycomb structure of the present invention, parallel to the direction in which the back hole extends (flow direction of the forming raw material). In FIG. 1, arrow A is the flow direction of the forming raw material. As shown in FIG. 1, the honeycomb structure forming die 1 of the present embodiment includes an introduction portion 3 provided on one surface (introduction-side surface 8) side and having a plurality of back holes 7, and the other surface side. The back plate 5 is provided with a plate-shaped base body 4 having a molding part 2 provided with a slit 6 that communicates with the back hole 7, and a flow hole 9 that communicates with the back hole 7 of the introduction part 3. However, the back plate 5 is a plate-shaped die for forming a honeycomb structure having a diamond-like carbon film (DLC film 11) on the surface thereof. According to the honeycomb structure forming die 1 of the present embodiment, the forming raw material introduced from the back hole 7 of the introduction part 3 through the flow hole 9 from the back plate introduction surface 8 is used as the slit of the formation part 2. 6 can be formed into a honeycomb shape. The obtained honeycomb structure includes partition walls formed so as to partition and form a plurality of cells extending in the axial direction, and may include an outer peripheral wall disposed so as to surround the entire partition walls. Here, the back plate introduction surface 8 is the surface of the back plate 5 that is not in contact with the base body 4. The slits 6 are preferably formed in a lattice shape on a surface perpendicular to the flow direction of the forming raw material, and the back holes 7 are preferably provided corresponding to the positions where the lattice-shaped slits 6 intersect. The slit 6 may be provided so as to extend from the molding portion 2 to a part of the introduction portion 3, and the back hole 7 may be formed in the introduction portion 3 so as to communicate with the slit 6. The hole 7 may be provided so as to extend from the introduction part 3 to a part of the molding part 2, and the slit 6 may be formed so as to communicate with the back hole 7. In FIG. 1, the base body 4 and the back plate 5 are shown separated from each other, but the base body 4 and the back plate 5 are used in contact with each other during use.

  Thus, since the back plate 5 having the DLC film 11 on the surface is disposed so as to be in contact with the introduction-side surface 8 of the introducing portion 3, due to the high smoothness of the DLC film disposed on the back plate, It is possible to suppress variations in fluidity of the forming raw material. Further, the back plate can be used over a long period of time due to the high wear resistance of the DLC film. Further, the DLC film only needs to be coated on the surface of the back plate 5, and it is not necessary to coat the base body 4. Therefore, the coating can be easily performed. Furthermore, since the back plate 5 is detachably disposed on the introduction-side surface 8 of the base body 4, one back plate can be used for a plurality of bases.

  FIG. 2 is a cross-sectional view parallel to the direction in which the back hole extends, schematically showing a state in which one embodiment of the die for forming a honeycomb structure of the present invention is fixed by a masking plate at a tip portion of an extruder. It is. In FIG. 2, the other parts of the extruder are omitted. In FIG. 2, the honeycomb structure forming die 1 is arranged such that the forming portion 2 faces the downstream side (the introduction portion 3 faces the upstream side), and the ring-shaped adjustment ring 22 positioned on the upstream side and the downstream side It is fixed by being sandwiched by a spacer 23 with a ring-shaped masking plate 21 located at the position. Here, the upstream side refers to the upstream side in the flow direction (extrusion direction) of the forming raw material, and the downstream side refers to the downstream side in the flow direction (extrusion direction) of the forming raw material.

  As shown in FIG. 2, when the forming raw material is flowed in the flow direction A and introduced into the honeycomb structure forming die 1, most of the forming raw material is directly introduced into the back hole 7 of the introduction portion 3, and the narrow slit 6 Then, it is extruded as a honeycomb structure formed body from the opening of the slit. A part of the forming raw material enters the gap between the honeycomb structure forming die 1 and the adjustment ring 22 as shown by the flow (a horizontal flow) A1 of the forming raw material, and the back hole 7 passes through the gap. And is pushed out from between the masking plate 21 and the molding portion 2. At this time, the forming raw material extruded from between the masking plate 21 and the forming portion 2 forms the outer peripheral wall of the honeycomb structure.

  Conventionally, the flow rate of the forming raw material introduced from the back hole into the slit varies depending on the location due to unevenness of the surface on which the forming raw material is introduced and the flowability of the forming raw material, and the partition wall of the resulting honeycomb structure In some cases, the thickness (rib thickness) does not become a desired constant thickness. In particular, when the flow rate of the lateral flow A1 is too large, the outer peripheral wall may be too thick, or the outer wall speed during molding may be too high. In such a case, by reducing the inner diameter of the adjustment ring 22 (ring-shaped inner diameter (diameter of the hole penetrating the central portion)) or the like, the flow rate of the lateral flow A1 is reduced, etc. It was necessary to control the wall thickness. However, for example, when the inner diameter of the adjustment ring 22 is reduced to reduce the supply amount of the forming raw material for forming the outer peripheral wall, the distance passing through the gap between the back plate introduction surface 10 and the adjustment ring 22. However, the outer wall thickness varies greatly and the speed variation sometimes increases. Moreover, since the supply amount of the forming raw material for forming the partition wall in the vicinity of the outer peripheral wall is also reduced, the thickness of the partition wall may be reduced. As described above, when the partition wall thickness is reduced, the strength of the honeycomb structure is lowered, a product buckling failure occurs at the time of molding, and the production efficiency may be lowered due to the modification of the operation conditions.

  When the honeycomb structure forming die 1 of the present embodiment is used, the surface on which the forming raw material is introduced becomes the back plate introduction surface 10. Therefore, the unevenness of the surface on which the conventional forming raw material is introduced due to the smoothness of the DLC film. Variation in the flow of the forming raw material is reduced, and the thicknesses of the outer peripheral wall and the partition wall can be easily controlled. It is preferable that the plurality of flow holes 9 formed in the back plate 5 have substantially the same hole diameter. The hole diameter of the flow hole 9 is preferably the same as the hole diameter of the corresponding back hole 7 formed in the introduction part 3. However, the hole diameter of the flow hole 9 corresponding to the position where the molding raw material for forming the outer peripheral wall is introduced may be reduced, so that the desired outer peripheral wall thickness and partition wall thickness can be obtained even in the case of a molding raw material having extremely good fluidity. A honeycomb structure having a thickness can be formed.

  The honeycomb structure forming die 1 of the present embodiment has a higher wear resistance than the wear resistance of the DLC film because the surface into which the forming raw material is introduced is the back plate introduction surface 10. For example, when the honeycomb structure forming die 1 of the present embodiment is arranged as shown in FIG. 2, the back plate introduction surface 10 is usually worn and cheap due to the flow A1 in the lateral direction during extrusion molding. Become. That is, a portion of the back plate introduction surface 10 that overlaps with the adjustment ring 22 tends to be greatly worn. If wear occurs in this portion, the gap between the back plate introduction surface 10 and the adjustment ring 22 becomes uneven and large, so that the flow rate of the lateral flow A1, that is, the outer peripheral wall of the honeycomb structure is increased. As a result, the amount of the forming raw material forming the material becomes uneven and large, and the honeycomb structure is deformed. However, the honeycomb structure forming die 1 of the present embodiment can suppress such wear due to the high wear resistance of the DLC film on the back plate introduction surface 10. If the conventional die for forming a honeycomb structure was used, it was necessary to replace the entire worn die or to rework the worn introduction surface into a flat shape by grinding or the like. Since the honeycomb structure forming die 1 of the embodiment only needs to replace the back plate 5, the state of the honeycomb structure forming die 1 can be satisfactorily maintained at a low cost.

  The back plate 5 constituting the honeycomb structure forming die 1 of the present embodiment is a plate-like member having a predetermined thickness, and has a plurality of flow holes 9 penetrating in the direction perpendicular to the surface. A diamond-like carbon film (DLC film 11) is disposed on the surface.

Diamond-like carbon (DLC) is a carbon having SP ³ bonds between carbon atoms similar to natural diamond and SP ² bonds between carbon atoms similar to graphite, and partially having a bond with hydrogen. It is a substance with an amorphous structure as the main component. DLC is excellent in high hardness, low wear, low friction and surface smoothness.

  The thickness of the DLC film 11 is preferably 0.01 to 10 μm, more preferably 0.1 to 5 μm, and particularly preferably 1 to 3 μm. If it is thinner than 0.01 μm, it may be difficult to exhibit smoothness and wear resistance. If it is thicker than 10 μm, DLC will be used wastefully.

DLC film 11 that are disposed on the surface side (the back plate introduction surface 10) of the forming material of at least the back plate 5 is introduced. It is good preferable disposed on the entire back plate introduction surface 10. As a result, the effect of suppressing the variation in fluidity of the molding raw material due to the high smoothness of the DLC film and the effect of enabling the long-term use of the back plate due to the high wear resistance of the DLC film are more effective. Can be obtained.

  The thickness of the back plate 5 is preferably 0.5 to 5 mm, and more preferably 1 to 3 mm. If it is thinner than 0.5 mm, the back plate 5 may be deformed or cracked during extrusion molding. If it is thicker than 5 mm, the honeycomb structure forming die may be too thick. Pressure loss may increase during molding.

  The outer peripheral shape and the size of the back plate 5 are not particularly limited, but it is preferable that the outer peripheral shape and the size of the base body 4 be the same. For example, as shown in FIG. 3, a circular shape is preferable. Here, FIG. 3 is a plan view schematically showing a back plate constituting one embodiment of the die for forming a honeycomb structure of the present invention.

  The material of the back plate 5 is not particularly limited, but it is preferable to use stainless steel, tool steel, cemented carbide or the like.

  It is preferable that all of the plurality of flow holes 9 formed in the back plate 5 have substantially the same hole diameter. Here, “substantially the same hole diameter” means that the hole diameters of the plurality of flow holes are in a range of ± 10% with respect to the average value. The term “hole diameter” refers to the longest diameter in the cross-sectional shape of the flow hole parallel to the surface of the back plate. For example, it is a diameter in the case of a circle, a major axis in the case of an ellipse, and a diagonal line (the longest) in the case of a polygon such as a square or rectangle. Moreover, it is preferable that the flow hole 9 is formed with the same hole diameter as the corresponding back hole 7 of the introduction part 3.

  A region (arrangement region) in which the plurality of flow holes 9 formed in the back plate 5 are arranged is not particularly limited, and can be appropriately determined according to the back hole 7 of the introduction portion 3. For example, it is preferable that the arrangement area of the flow holes 9 is a circular area as shown in FIG. 3 or a polygonal area such as a quadrangle.

  The base body 4 constituting the honeycomb structure forming base 1 of the present embodiment may be one in which the forming portion 2 and the introduction portion 3 are integrally formed, or the forming portion 2 and the introduction portion 3. May be formed from different members, and these two types of members (or two members of the same type) may be bonded together using a binder. Moreover, it is preferable that the back plate 5 is detachably disposed on the introduction portion 3 by bolting, pin fitting, or the like. When performing bolt fastening, as shown in FIG. 3, it is preferable to form the hole 31 for letting a bolt pass to the outer edge part of the back plate 5. FIG.

  The base body 4 is plate-shaped, but the outer peripheral shape thereof is not particularly limited, and can be appropriately determined according to the shape of the tip of the extrusion machine to be mounted. For example, a circle, an ellipse, a quadrangle, etc. can be mentioned. This outer peripheral shape is the outer peripheral shape of the molding part 2, the introduction part 3 and the back plate 5.

  The size of the base body 4 is not particularly limited, and can be appropriately determined according to the size of the honeycomb structure to be formed. For example, in the case of a disk shape, those having a diameter of 150 to 600 mm and a thickness of 10 to 100 mm can be suitably used.

  The thickness (length in the flow direction of the forming raw material) of the forming portion 2 constituting the base body 4 is not particularly limited, but is 1 to 7 mm from the viewpoint of the formability of the honeycomb structure. Is preferred.

  Examples of the material of the molded part 2 include stainless steel, tool steel, and cemented carbide.

  The slits 6 formed in the molding part 2 are preferably formed in a lattice shape, and the shape of the lattice is preferably a square, a hexagon, other polygons, or the like. The width of the slit 6 and the interval between adjacent slits 6 are not particularly limited, and can be appropriately determined according to the partition wall thickness and cell size of the honeycomb structure to be formed. For example, the width of the slit is preferably about 0.05 to 0.4 mm, and the interval between adjacent slits is preferably about 0.6 to 2.5 mm.

  The shape of the arrangement region of the slit 6 on the surface of the molding part 2 is not particularly limited, and can be appropriately determined according to the shape of the honeycomb structure to be molded. For example, a circle, an ellipse, a rectangle, a hexagon, other polygons, and the like can be given.

  In addition, the thickness of the introduction portion 3 constituting the honeycomb structure forming die 1 of the present embodiment is not particularly limited, but is preferably 10 to 100 mm from the viewpoint of strength and pressure loss.

  Examples of the material of the introduction part 3 include stainless steel, tool steel, and cemented carbide.

  The shape of the cross section of the back hole 7 formed in the introduction portion 3 parallel to the introduction-side surface 8 is not particularly limited, and can be appropriately determined depending on the ease of processing, the ease of flow of the forming raw material, and the like. . For example, a polygon such as a circle, an ellipse, or a quadrangle can be used.

  Further, the arrangement position of the back hole 7 is not particularly limited, but it is preferably formed so as to communicate with the crossing position of the slit 6 formed in a lattice shape, and the center of the back hole 7 is arranged at the crossing position of the slit 6. More preferably, it is made to be. The hole diameter of the back hole 7 (the diameter of the cross section parallel to the introduction surface 8) and the distance between the adjacent back holes 7 are not particularly limited, and can be determined as appropriate depending on the width of the slit 6 and the formation position. For example, when the cross-sectional shape of the back hole is circular, the hole diameter is preferably about 0.50 to 2.50 mm. Moreover, the shape of the arrangement area of the back hole 7 formed in the introduction part 3 is not particularly limited, but is preferably the same shape as the arrangement area of the slit 6.

  Next, the manufacturing method of one embodiment of the die for forming a honeycomb structure of the present invention will be described. First, a back hole for introducing a forming raw material for forming the honeycomb structure is formed on one surface 10 of the plate-like member having two surfaces, and the back surface communicates with the other surface of the die base. A slit forming die base is obtained by forming a slit. Next, a wear-resistant surface layer is formed on at least a part of the portion where the back hole and the slit are formed on the obtained slit-forming die base by a process including electroless plating to obtain a die for forming a honeycomb structure. .

  The shape and size of the slit and the back hole are preferably the same as the shape and size of the slit and the back hole in one embodiment of the honeycomb structure forming die of the present invention.

  Further, the outer edge portion of the base body on the molding part side may be recessed by grinding or the like. In this case, the shape of the honeycomb structure forming die becomes a shape in which the outer edge portion is thinned by grinding or the like of the outer edge portion of the forming portion. Thus, as shown in FIG. 2, when the die for forming a honeycomb structure is attached to the extrusion molding machine, the masking plate 21 can be fitted into the recessed portion (thinned portion), so that the attachment is stable. It becomes possible to do.

  The back plate first forms a back hole having the same position and size (hole diameter) as the back hole formed in the introduction portion in the plate-like third member. The thickness, outer peripheral shape, and the like of the third member are preferably the same as those of the back plate in the embodiment of the honeycomb structure forming die of the present invention. The back hole can be formed by laser processing, drilling, electrolytic processing, or the like.

  Next, a DLC film is formed on one surface of the back plate (back plate introduction surface). At this time, even if a film containing at least one of Cr, Ti, Si, and C is plated or coated on the surface of the back plate, there is no problem in the DLC film formation. The film thickness of the DLC film is preferably set to a preferable film thickness of the DLC film in the embodiment of the honeycomb structure forming die of the present invention. As a film formation method, a plasma CVD method or a sputtering method can be used. In the plasma CVD method, chemical reactions such as decomposition and bonding of source gases are caused in a low-pressure environment by using plasma energy generated in a vacuum vessel using high-frequency power, direct-current power, direct-current pulse power, or the like. This is a method of forming a thin film on the third member heated to 100 to 200 ° C. Sputtering uses an electric field in a vacuum vessel to ionize an inert gas such as argon in a low-pressure environment, accelerates the ionized ions, and bombards the target material. The thin film is formed by depositing on the third member. At this time, sputtering may be performed while mixing a gas such as hydrogen or an alkyl compound. In the plasma CVD method, an alkyl compound or the like can be used as a source gas. In the sputtering method, carbon or the like can be used as a target material.

  Next, the die for forming a honeycomb structure of the present embodiment can be obtained by attaching the back plate to the introduction portion side of the obtained die main body by screwing and detachably attaching the pins. At this time, as shown in FIG. 1, it is preferable to mount the back plate 5 so that the back hole 7 formed in the back plate 5 and the back hole 7 formed in the introduction portion 3 are in the same position. Further, the surface of the back plate 5 on which the DLC film 11 is disposed (back plate introduction surface 10) faces the side where the forming raw material is introduced, and the surface where the DLC film 11 is not disposed faces the introduction portion 3 side. In this manner, the back plate 5 is attached to the base body.

  The die for forming a honeycomb structure of the present invention can be used for extrusion molding of a ceramic honeycomb structure, and according to the present invention, even if the surface (introduction surface) on the raw material introduction side is worn during extrusion molding, In addition, the worn portion can be replaced, and the shape of the formed honeycomb structure can be maintained well.

1 is a cross-sectional view parallel to the direction in which a back hole extends, schematically showing an embodiment of a die for forming a honeycomb structure of the present invention. 1 is a cross-sectional view parallel to the direction in which a back hole extends, schematically showing a state in which one embodiment of a die for forming a honeycomb structure of the present invention is fixed by a masking plate at a tip portion of an extruder. FIG. 2 is a plan view schematically showing a back plate constituting one embodiment of a die for forming a honeycomb structure of the present invention.

1: honeycomb structure forming die, 2: forming part, 3: introducing part, 4: die body, 5: back plate, 6: slit, 7: back hole, 8: introduction side surface, 9: flow hole, 10: Back plate introduction surface, 11: DLC film, 21: Masking plate, 22: Adjustment ring, 23: Spacer, 31: Hole for passing bolt, A: Flow direction of forming raw material, A1: Flow in lateral direction.

Claims (4)

A plate-shaped base having an introduction portion provided on one surface (surface on the introduction side) and having a plurality of back holes, and a molding portion provided on the other surface side and formed with a slit communicating with the back hole. A plate-shaped honeycomb structure forming die that includes a main body and forms a forming raw material introduced from a back hole of the introduction portion into a honeycomb shape through a slit of the formation portion,
A back plate formed with a plurality of flow holes communicating with the back hole of the introduction part is detachably disposed on the introduction side surface,
Only the back plate has a diamond-like carbon film (DLC film) on its surface,
The DLC film is disposed on at least a surface of the back plate on which a forming raw material is introduced;
The flow hole of the back plate and the back hole of the introduction part have the same hole diameter,
A die for forming a honeycomb structure in which the flow hole of the back plate and the back hole of the introduction portion overlap with each other without deviation.   The die for forming a honeycomb structure according to claim 1, wherein the DLC film has a thickness of 0.01 to 10 µm. The die for forming a honeycomb structure according to claim 1 or 2 , wherein all of the plurality of flow holes formed in the back plate have substantially the same hole diameter. The die for forming a honeycomb structure according to any one of claims 1 to 3 , wherein the back plate is detachably disposed on the introduction portion by bolting or pin fitting.

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