Grinding method of honeycomb structure

A grinding method of a honeycomb structure which subjects an outer peripheral portion of a joined honeycomb segment assembly to grind processing by use of a disc-like grind processing member,

• the grind processing member including a disc-like disc portion and a ring-like grinding wheel portion disposed on an outer periphery of the disc portion,
• wherein in a state where a central axis of the grind processing member is parallel to a central axis of the joined honeycomb segment assembly, the outer peripheral portion of the joined honeycomb segment assembly is ground by the grinding wheel portion of the grind processing member, while rotating the joined honeycomb segment assembly around the central axis and rotating the grind processing member around the central axis, to prepare the honeycomb structure including a columnar honeycomb base material and a ring-like bulge portion,
• the grinding wheel portion of the grind processing member has an outer peripheral surface formed in parallel with the central axis, a first grinding wheel tapered surface formed at one end in a central axis direction in such a tapered manner as to decrease an outer diameter of a tip, and a second grinding wheel tapered surface formed at the other end in the central axis direction in such a tapered manner as to decrease the outer diameter of the tip, and
• the joined honeycomb segment assembly is an assembly to be ground which is formed by joining side surfaces of a plurality of ceramic honeycomb segments to one another,
• the grinding method of the honeycomb structure having:
• a first ground region forming step where the grinding wheel portion of the grind processing member grinds a part of the outer peripheral portion of the joined honeycomb segment assembly having a first end as one end and a second end as the other end, on the side of the first end, to form a first ground region of the honeycomb base material and a first tapered portion of the ring-like bulge portion;
• a second ground region forming step where the grinding wheel portion of the grind processing member grinds a part of a non-ground region of the outer peripheral portion of the joined honeycomb segment assembly as a region which is not ground, on the side of the second end, to form a second ground region of the honeycomb base material and a second tapered portion of the ring-like bulge portion;
• and
• a center ground surface forming step, which is performed after the first and second ground region forming steps are completed, where the grinding wheel portion of the grind processing member grinds a remaining non-ground region of the outer peripheral portion of the joined honeycomb segment assembly as a region which is left non-ground, to form a center ground surface of the ring-like bulge portion,
• wherein in the first ground region forming step, the grind processing member is set to a grinding position for the first ground region before contacting the joined honeycomb segment assembly, then the first ground region is formed by grinding of the grind processing member moving only in parallel to the central axis of the joined honeycomb segment assembly from the first end toward the second end of the joined honeycomb segment assembly such that the outer peripheral surface of the grinding wheel portion forms the first ground region, and the first grinding wheel tapered surface of the grinding wheel portion forms the first tapered portion which tapers toward the first end, between the non-ground region which is not ground on the second end side and the first ground region,
• in the second ground region forming step, the grind processing member is set to a grinding position for the second ground region before contacting the joined honeycomb segment assembly, then the second ground region is formed by grinding of the grind processing member moving only in parallel to the central axis of the joined honeycomb segment assembly from the second end toward the first end of the joined honeycomb segment assembly such that the outer peripheral surface of the grinding wheel portion forms the second ground region, and the second grinding wheel tapered surface of the grinding wheel portion forms the second tapered portion which tapers toward the second end, between the remaining non-ground region which is not ground left non-ground and the second ground region, and then
• in the center ground surface forming step, the grind processing member is set to a grinding position for the center ground surface before contacting the joined honeycomb segment assembly, then the center ground surface is formed by grinding of the grind processing member moving only in parallel to the central axis of the joined honeycomb segment assembly from one of the first end and the second end toward the other of the first end and the second end of the joined honeycomb segment assembly such that the center ground surface formed in the center ground surface forming step is the surface which comes in contact with a first tapered surface which is the tapered surface of the first tapered portion and a second tapered surface which is the tapered surface of the second tapered portion,
• the honeycomb base material of the honeycomb structure is formed by joining the side surfaces of the plurality of ceramic honeycomb segments to one another, and
• the ring-like bulge portion of the honeycomb structure surrounds an outer periphery of the honeycomb base material, protrudes from the outer periphery of the honeycomb base material toward the outside in a flange manner, and has the first tapered surface, the second tapered surface and the center ground surface.