Method for manufacturing cylindrical honeycomb fired body

Patent metadata

Field	Value
Publication number	US-12420469-B2
Application number	US-202318167241-A
Country	US
Kind code	B2
Filing date	Feb 10, 2023
Priority date	Mar 31, 2022
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

A method for manufacturing a cylindrical honeycomb fired body including: preparing a cylindrical honeycomb formed body; obtaining a cylindrical honeycomb dried body by drying the cylindrical honeycomb formed body; calculating predetermined parameters (E AVE1 , E AVE2 , E AVE3 and E AVE4 ) from average values of distance between a center of gravity position O and an outer peripheral contour in a plurality of predetermined angle ranges; specifying a minimum value of the predetermined parameters; obtaining a cylindrical honeycomb fired body by placing the cylindrical honeycomb dried body on a shelf plate and firing it while passing it through a continuous firing furnace, such that the direction in which the cells of the cylindrical honeycomb dried body extend vertically, and a particular location on the outer peripheral side surface determined according to the minimum value is positioned at the front.

First claim

The invention claimed is:

1. A method for manufacturing a cylindrical honeycomb fired body, the cylindrical honeycomb fired body comprising an outer peripheral side surface, and partition walls disposed on an inner peripheral side of the outer peripheral side surface and partitioning a plurality of cells forming flow paths from a first end surface to a second end surface, the method comprising:
a step A of preparing a cylindrical honeycomb formed body by extrusion molding a green body comprising a ceramic raw material, a pore-forming material, a binder and a dispersion medium through a die defining an opening shape of the plurality of cells and an annular mask located downstream of the die and having an inner peripheral contour for defining an outer peripheral contour of the first end surface and the second end surface, such that a direction in which the cells extend is horizontal and a front side in a traveling direction of the extrusion molding is the first end surface, and a rear side is the second end surface, and then by cutting to a predetermined length;
a step B of obtaining a cylindrical honeycomb dried body by drying the cylindrical honeycomb formed body;
a step C of calculating:
( D 1AVE +D 4AVE +D 6AVE )−( D 2AVE +D 5AVE +D 8AVE )= E AVE1 ,

( D 3AVE +D 6AVE +D 8AVE )−( D 2AVE +D 4AVE +D 7AVE )= E AVE2 ,

( D 2AVE +D 5AVE +D 8AVE )−( D 1AVE +D 4AVE +D 6AVE )= E AVE3 , and

( D 2AVE +D 4AVE +D 7AVE )−( D 3AVE +D 6AVE +D 8AVE )= E AVE4 ,

in which, assuming that a cross-section perpendicular to the direction in which the cells of the cylindrical honeycomb dried body extend is observed from the front side in the traveling direction of the extrusion molding of the step A, and a location on the outer peripheral side surface located at a vertex during the extrusion molding in the step A is 0 rad, with a clockwise direction as a + direction, D 1AVE is defined as an average value of distance between a center of gravity position O and an outer peripheral contour of the cross-section in a central angle (rad) from −⅛π to +⅛π, D 2AVE is defined as an average value of distance between the center of gravity position O and the outer peripheral contour of the cross-section in a central angle (rad) from +⅛π to +⅜π, D 3AVE is defined as an average value of distance between the center of gravity position O and the outer peripheral contour of the cross-section in a central angle (rad) from +⅜π to +⅝π, D 4AVE is defined as an average value of distance between the center of gravity position O and the outer peripheral contour of the cross-section in a central angle (rad) from +⅝π to +⅞π, D 5AVE is defined as an average value of distance between the center of gravity position O and the outer peripheral contour of the cross-section in a central angle (rad) from +⅞π to +9/8π, D 6AVE is defined as an average value of distance between the center of gravity position O and the outer peripheral contour of the cross-section in a central angle (rad) from +9/8π to +11/8π, D 7AVE is defined as an average value of distance between the center of gravity position O and the outer peripheral contour of the cross-section in a central angle (rad) from +11/8π to +13/8π, and D 8AVE is defined as an average value of distance between the center of gravity position O and the outer peripheral contour of the cross-section in a central angle (rad) from +13/8π to +15/8π;
a step D of specifying a minimum value among E AVE1 , E AVE2 , E AVE3 , and E AVE4 calculated in the step C;
a step E of obtaining the cylindrical honeycomb fired body by placing the cylindrical honeycomb dried body on a shelf plate and firing the cylindrical honeycomb dried body while passing it through a continuous firing furnace, such that the direction in which the cells of the cylindrical honeycomb dried body extend is parallel to a vertical direction and:
when the minimum value is E AVE1 , a location on the outer peripheral side surface corresponding to 0 rad is positioned at the front side in the traveling direction of the extrusion molding,
when the minimum value is E AVE2 , a location on the outer peripheral side surface corresponding to 4/8 π rad is positioned at the front side in the traveling direction of the extrusion molding,
when the minimum value is E AVE3 , a location on the outer peripheral side surface corresponding to 8/8 π rad is positioned at the front side in the traveling direction of the extrusion molding, and
when the minimum value is E AVE4 , a location on the outer peripheral side surface corresponding to 12/8 π rad is positioned at the front side in the traveling direction of the extrusion molding.

2. The method for manufacturing the cylindrical honeycomb fired body according to claim 1 , wherein the step B comprises placing the honeycomb formed body in a dryer such that the direction in which the cells extend is the vertical direction, and drying the honeycomb formed body while passing it through the dryer such that the location on the outer peripheral side surface located at the vertex during the extrusion molding in the step A is positioned at the front side in the traveling direction of the extrusion molding.

3. The method for manufacturing the cylindrical honeycomb fired body according to claim 1 , comprising determining whether or not the minimum value specified in the step D satisfies a predetermined criterion, and performing the step E only when the minimum value satisfies the predetermined criterion.

4. The method for manufacturing the cylindrical honeycomb fired body according to claim 3 , comprising determining whether or not the minimum value specified in the step D satisfies the predetermined criterion, and when the minimum value does not satisfy the predetermined criterion, performing a step F instead of the step E, the step F comprising preparing an annular mask with a modified inner peripheral contour according to the minimum value, such that a minimum value among E AVE1 , E AVE2 , E AVE3 , and E AVE4 of a next cylindrical honeycomb dried body to be prepared can satisfy the criterion; and the method further comprising thereafter repeating the steps A to D again provided that the modified annular mask is used.

5. The method for manufacturing the cylindrical honeycomb fired body according to claim 3 , wherein the predetermined criterion is that the minimum value is in the range of −0.3 mm to −0.1 mm.

6. The method for manufacturing the cylindrical honeycomb fired body according to claim 1 , wherein for calculating E AVE1 , E AVE2 , E AVE3 , and E AVE4 , the step C comprises in sequence:
placing the cylindrical honeycomb dried body on a rotary stage with the first end surface or the second end surface facing upward; and
continuously measuring distance using a displacement gauge between an arbitrary point on the outer peripheral side surface of the cylindrical honeycomb dried body and the displacement gauge while rotating the rotary stage for one revolution.

7. A method for manufacturing a cylindrical honeycomb fired body, the cylindrical honeycomb fired body comprising an outer peripheral side surface, and partition walls disposed on an inner peripheral side of the outer peripheral side surface and partitioning a plurality of cells forming flow paths from a first end surface to a second end surface, the method comprising:
a step A of preparing a cylindrical honeycomb formed body by extrusion molding a green body comprising a ceramic raw material, a pore-forming material, a binder and a dispersion medium through a die defining an opening shape of the plurality of cells and an annular mask located downstream of the die and having an inner peripheral contour for defining an outer peripheral contour of the f

Assignees

• Ngk Insulators Ltd

Inventors

• Yamazaki Yasunori
• Kageyama Kazuya
• Hayakawa Yusuke

Classifications

• B29C48/92 Primary

  Measuring, controlling or regulating · CPC title

• B29C2948/92666

  Distortion, shrinkage, dilatation, swell or warpage · CPC title

• B29L2031/608

  Honeycomb structures · CPC title

• B29D99/0089

  Producing honeycomb structures (consisting of porous ceramic ware C04B38/0006) · CPC title

• B28B11/007

  Using a mask for plugging · CPC title