| 摘要 |
PURPOSE:To make possible the molding of a piston ring having a small joint by fitting a key having the width of the same size as the width of the free joint gap of the piston ring into the recesses provided to a die and core as well as upper and lower punches forming an alloy powder packing cavity. CONSTITUTION:The recesses 8, 7, 2, 4 are respectively formed to the die 6, core 5 and upper and lower punches 1, 3 of molding tools for the sintered alloy piston ring consisting of the combination of the die 6 and core 5 as well as upper and lower punches 1, 3 forming the alloy powder packing gap corresponding to the shape of the free state of the piston ring. The key 9 having the width of the same size as the size of the free joint gap of the piston ring is disposed to be fitted into said recesses. The inexpensive molding dies which withstand the long-period use without rupturing even after molding of the piston ring having the small joint and permits the easy positioning so as to meet the joint part are thus obtd.
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