Patent ID: 7749458

Claim:
A honeycomb structure comprising: two or more honeycomb segments, each having a large number of through channels that are partitioned by walls and penetrate in axial directions, said walls of said through channels having a filtering function, said structure being constructed so that one end is clogged for predetermined through channels, and the other end is clogged for the remaining through channels, wherein a corner portion of a cross-sectional shape of at least one of said honeycomb segments in a cross-section perpendicular to said through channels of said honeycomb structure has a rounded shape with a radius of curvature of 0.3 mm or larger; and one or more joint layers joining said two or more honeycomb segments to each other; wherein a ratio of a cross-sectional area of the joint layers to a cross-sectional area of the walls in a cross-section of the honeycomb structure perpendicular to the through channels of the honeycomb structure is higher in a central portion of the honeycomb structure than in an outer peripheral portion of the honeycomb structure; wherein said honeycomb segments and said joint layers comprise materials wherein a material strength of said joint layers is lower than a material strength of said honeycomb segments; wherein a portion having an area of at least 30% of the surface area of said honeycomb segment in contact with said joint layer has an average surface roughness Ra exceeding 0.4 micron; wherein a ratio of a total heat capacity of all said joint layers in said honeycomb structure to a total heat capacity of all said honeycomb segments constituting said honeycomb structure is 30% or lower; wherein a ratio of a sum of the cross-sectional areas of said joint layers to a sum of the cross-sectional areas of said walls in a cross-section of said honeycomb structure perpendicular to said through channels of said honeycomb structure is 50% or lower; and wherein a ratio of a total cross-sectional area of said joint layers to a cross-sectional area of said honeycomb structure in a cross-section perpendicular to said through channels of said honeycomb structure is 17% or lower.