A pillar shaped honeycomb structure including pillar shaped honeycomb segments joined together via joining material layers, wherein each of the pillar shaped honeycomb segment includes: an outer peripheral wall; and a porous partition wall disposed on an inner side of the outer peripheral wall, the partition wall defining a plurality of cells, each of the cells extending from one end face to other end face to form a flow path, and wherein a metal member is embedded in each of the joining material layer.

A joining material used for joining side surfaces of a plurality of silicon carbide-based honeycomb segments to each other to produce a silicon carbide-based honeycomb structure. The joining material contains from 0.1 to 50% by mass of processed powder generated in the production of the silicon carbide-based honeycomb segments and/or the silicon carbide-based honeycomb structure. The joining material has an average particle diameter D50 of from 0.5 to 60 μm.

A honeycomb structure includes a plurality of prismatic columnar shaped honeycomb segments; a bonding layer bonding side faces of the honeycomb segments; and a circumferential wall disposed to surround a honeycomb segment bonded body having the honeycomb segments arranged in a grid pattern and bonded with the bonding layer, wherein the honeycomb segments has a porous partition wall disposed to surround a plurality of cells, the cells in other than outermost circumference have a hexagonal shape in a section orthogonal to the cell extending direction, the honeycomb segments include first and second honeycomb segment, the second honeycomb segment is different from the first in at least one of: a shape in the section; a size; and an arrangement direction of the cells and an extended line of one diagonal line imaginarily depicted in the cells in the first honeycomb segment and that in the second are configured to be orthogonal.

Disclosed is an air filter and a method of manufacture for an air filter which is much more cost effective and provides greater operational effectiveness than state-of-the-art air filters. The air filter includes an outer metallic shell which may be used to attach the filter in line to ducting of a heating, ventilation, and air conditioning (HVAC) system. The filter may further include a filter unit made of activated carbon material. The filter unit may have one or more sections and may have a honeycomb cross section.

A particulate filter 23 is configured by being provided with, arranged side by side, a plurality of honeycomb-shaped segments 29, 30, 31 having a plurality of cells 32. The density of cells in the segments 30, 31 disposed in the outer circumference part is set to be lower than the density of cells in the segments 29 disposed in the center part. In addition, the segments 30, 31 disposed in the outer circumference part are configured so that the density of the cells 32 becomes lower as the area of the end face becomes smaller.

A particulate filter 23 is configured by being provided with, arranged side by side, a plurality of honeycomb-shaped segments 29, 30, 31 having a plurality of cells 32. The density of cells in the segments 30, 31 disposed in the outer circumference part is set to be lower than the density of cells in the segments 29 disposed in the center part. In addition, the segments 30, 31 disposed in the outer circumference part are configured so that the density of the cells 32 becomes lower as the area of the end face becomes smaller.

A manufacturing method of a honeycomb structure including: a formed body forming step of extruding a forming raw material, to form a plurality of quadrangular prismatic columnar honeycomb formed bodies; a firing step of firing the honeycomb formed bodies, to form a plurality of quadrangular prismatic-columnar quadrangular segments; a triangular segment forming step to form a triangular prismatic-columnar triangular segment; a bonded body forming step to form a honeycomb bonded body; and a circumference grinding step to manufacture the honeycomb structure, wherein the bonded body forming step further includes: a pressurizing step of pressurizing the triangular segment from a circumferential direction of the temporary assembly toward a central direction thereof, by use of a pressurizing jig comprising a pressurizer.

A honeycomb filter includes a plugged honeycomb structure body which has cell rows arranged along one direction, in a cross section of the honeycomb structure body and including a first cell row constituted of at least one of an inflow cell and an outflow cell, and a through-cell, and a second cell row including no through-cells. A width P1 (mm) of the first cell row, a width P2 (mm) of the second cell row and a curvature radius R (μm) of a curved shape of corner portions of a polygonal shape of each cell satisfy a relation of Equation (1) below: Equation (1): 0.4 (R/1000)/((P1+P2)/2) 100 20.

A honeycomb structure includes honeycomb segments, bonding layers and a circumferential wall. The bonding layers include bottomed-hollow voids which extend toward an internal side in an axial direction from an end face of the honeycomb structure and which are formed at at least one of intersections, and a ratio of a depth of each void in the axial direction to a length of each honeycomb segment in the axial direction is 5% or more.

A honeycomb filter includes a plugged honeycomb structure body which has cell rows arranged along one direction in a cross section of the honeycomb structure body and including a first cell row in which at least the inflow cells are included and in which in the cross section perpendicular to the extending direction of the cells, a through channel area SA occupied by the inflow cells is larger than a through channel area SB occupied by the outflow cells, and a second cell row in which at least the outflow cells are included. A width P1 (mm) of the first cell row, a width P2 (mm) of the second cell row and a curvature radius R (μm) of a curved shape of corner portions of a polygonal shape of each cell satisfy a relation of Equation (1) below: Equation (1): 0.4≤(R/1000)/((P1+P2)/2)×100≤20.