MECHANICAL FUSE AND MANUFACTURING METHOD FOR THE FUSE

摘要

PROBLEM TO BE SOLVED: To provide an inexpensive mechanical fuse and a manufacturing method for the fuse enhanced in formability and capable of achieving high reliability of rupture resistance by having the fuse carry a high fatigue limit. SOLUTION: The mechanical fuse is made of a sintered ferrous alloy and comprises an inner ring section 2 fixed to one of power-transfer shafts, an outer ring section 3 fixed to another power-transfer shaft, and a plurality of arm sections 4 for connecting the inner ring section 2 and the outer ring section 3. These sections are molded into one body. Rupturing sections 6 being ruptured when overloaded torque is applied are formed at the arm sections 4. A phase of iron oxide is formed on the surface and the inner wall of a pore. The phase of iron oxide makes round the pore and slows down the sensitivity of notching. Thereby, fatigue strength and the ratio of a fatigue limit can be enhanced.