Molding die, hollow ceramic monolithic support and method of manufacturing the same, and catalytic converter system

A method of manufacturing a hollow ceramic monolithic support, which comprises manufacturing a hollow ceramic monolithic support that has a hollow space in an inner periphery skin portion thereof, by extrusion molding a ceramic material using a molding die comprising a die that has an introduction hole section provided with introduction holes through which the material is introduced and a slit section having slits that communicate with the introduction holes for forming the material into honeycomb shape, an outer periphery guide ring that has an outer periphery erected portion extending from the outer peripheral end of said slit section along the extruding direction and an outer periphery protruding portion protruding from said outer periphery erected portion inward while being separated from the slit by a gap provided therebetween, and an inner periphery guide ring that has an inner periphery erected portion extending from the center of said slit section along the extruding direction and an inner periphery protruding portion protruding from said inner periphery erected portion outward while being separated from said slit section by a gap provided therebetween;

• wherein the outer periphery skin portion is formed from the ceramic material that passes through the gap between said outer periphery protruding portion and said slit section of said outer periphery guide ring, the inner periphery skin portion is formed from the ceramic material that passes through the gap between said inner periphery protruding portion and said slit section of said inner periphery guide ring, and the main body of the honeycomb structure surrounded by said inner periphery skin portion and said outer periphery skin portion is formed from the ceramic material that is extruded through said slit section, thereby to make the hollow ceramic monolithic support that has the hollow portion in the inner periphery skin portion.

A hollow ceramic monolithic support comprising:

• a main body that has a multitude of cells surrounded by ribs of honeycomb structure;
• a hollow space formed to penetrate said main body at the central portion thereof in the longitudinal direction;
• an outer periphery skin portion that covers the outer peripheral surface of said main body;
• and
• an inner periphery skin portion that covers the inner peripheral surface of said main body,
• wherein said ribs located in a layer in a range from one to 10 cells from said inner periphery skin portion are made to form a high strength portion that has higher strength than the other portion of ribs located outside thereof.