Honeycomb unit for exhaust emission control

A honeycomb unit for exhaust emission control, comprising:

• a metal outer tube;
• and
• a metal honeycomb structure pressed into and joined to the metal outer tube,
• the metal honeycomb structure including:
• a joining strip joined to the metal outer tube;
• a planar sheet;
• a corrugated sheet placed on the planar sheet, the corrugated sheet and the planar sheet being wound together, the corrugated sheet including an outer surface having crests and an inner surface having crests;
• first and second joining portions brazing the planar sheet and the corrugated sheet together;
• the first joining portion and the second joining portion being located proximate opposing ends of the metal honeycomb structure;
• the first joining portion including first joining sections formed of brazing materials applied to the crests of the outer surface of the corrugated sheet and second joining sections formed of brazing materials applied to the crests of the inner surface of the corrugated sheet;
• the second joining portion including first joining sections formed of brazing materials applied to the crests of the outer surface of the corrugated sheet and second joining sections formed of brazing materials applied to the crests of the inner surface of the corrugated sheet;
• the first joining sections of the first joining portion and the first joining sections of the second joining portion being offset from the second joining sections of the first joining portion and the second joining sections of the second joining portion in directions parallel to an axis of the metal honeycomb structure;
• the corrugated sheet being joined through the planar sheet to the joining strip;
• the joining strip overlapping the first joining sections of the second joining portion in a direction orthogonal to the axis of the metal honeycomb structure;
• the joining strip having a brazing length along the axis of the metal honeycomb structure;
• the first joining sections of the second joining portion each having a brazing length along the axis of the honeycomb structure;
• the brazing length of the joining strip being larger than the brazing length of each of the first joining sections of the second joining portion.