Patent ID: 7553148

Claim:
A production apparatus for bending a multi-channel tube having an outer tube and a partition partitioning an interior of the outer tube into two or more channel holes, the production apparatus comprising: a bending mold configured to bend the multi-channel tube in a bend radius; a pressure mold configured to press the multi-channel tube toward the bending mold; a chuck portion configured to hold and draw the multi-channel tube along the bending mold; and a plurality of mandrels respectively inserted into the channel holes, each of the mandrels including: a mandrel body configured to support inner surfaces of each channel hole; and a support device rotatably and movably supporting the mandrel body, wherein each of the mandrel bodies comprises a proximal portion having a cross sectional shape fitting with a cross sectional shape of the channel hole and including a curved surface portion and a flat surface portion, a relief bevel continuing with a distal end of the curved surface portion and being configured to avoid interference with the inner surfaces of the channel holes and a buckling prevention surface continuing with a distal end of the flat surface portion and being configured to contact the partition so as to prevent buckling deformation of the partition, and wherein the flat surface portion includes relief flanks formed by being diagonally and obliquely cut off from both sides of a proximal end of the flat surface portion and configured to avoid interference with the partition even when the partition is twisted.