| 摘要 |
A replaceable head cutting tool increases the strength of engagement between a tool body and a coupling member without causing damage to the tool body or the punch. A cylindrical mounting unit 21 of the coupling member 2, which is made of a metal material having hardness lower than the hardness of the tool body 1, is inserted into a mounting hole 16 that includes a concave portion 17 formed on the inner surface of the tool body 1 made of a hard material. The mounting unit 21 is plastically deformed so as to increase in diameter, and the outer peripheral surface of the mounting unit 21 comes into close contact with the inner peripheral surface of the mounting hole 16 and is engaged with the concave portion 17, so that the tool body 1 and the coupling member 2 are joined to each other. The concave portion 17 includes a first wall surface 17a that is inclined toward the outer peripheral side as the first wall surface moves in an insertion direction F of the mounting unit 21, and a second wall surface 17b that is opposite of the first wall surface 17a and is inclined toward the inner peripheral side as the second wall surface moves in the insertion direction F. A first inclination angle ±, which is formed between the first wall surface 17a and a plane S perpendicular to a center line of the mounting hole 16 at a position where the first wall surface 17a intersects with the inner peripheral surface of the mounting hole 16, is smaller than a second inclination angle ², which is formed between the second wall surface 17b and the plane S at a position where the second wall surface 17b intersects with the inner peripheral surface of the mounting hole 16. |
