Patent ID: 8156630

Claim:
A method for joining a first member and a second member, wherein the method comprises the steps of inserting the first member made of a tubular member having a hollow portion into an insertion hole provided in the second member, disposing a split die circumferentially split into multiple segments in the hollow portion of the first member, and then moving each of the segments of the split die radially outward of the first member to execute an expansion work of an insertion portion of the first member inserted in the insertion hole and both portions of the first member axially adjacent to the insertion portion to join the first member and the second member, characterized in that, the first member is a tubular member polygonal in cross-section, the insertion hole of the second member is formed into a cross-sectional shape corresponding to a cross-sectional shape of the first member, the split die is split at each position corresponding to each flat wall portion of the first member, and each segment of the split die disposed in the hollow portion of the first member is moved radially outward of the first member toward each corner portion of the first member to execute the expansion work.