| 摘要 |
PROBLEM TO BE SOLVED: To provide a tool socket that ensures fastening torque or loosening torque so as to reduce stress concentration generated in a square recess, thereby elongating life.SOLUTION: A tool socket 1 has an insertion hole 2 for inserting a polygonal head 31 of a polygonal bolt 3. The insertion hole 2 has the same number of inner wall surfaces 21 as the number of corner parts of the polygonal head 31. On each of the inner wall surfaces 21, one surface portion 23A adjacent to one side in a circumferential direction with respect to a square recess 22 formed between the inner wall surfaces 21 is located more outside in a radial direction than another surface portion 23B adjacent to another side in the circumferential direction with respect to the square recess 22. |
