| 摘要 |
PROBLEM TO BE SOLVED: To easily manufacture a latch plate which is formed as a gear having a tooth of high strength and precision and in which an arc-shaped groove is provided as a control member of a rotational range on its one surface by punching a square hole at the central part of a base stock with a high precise press, forming the arc-shaped groove on one surface of the base stock by forging and forming a tooth in the outer peripheral part of the base stock by cold forging. SOLUTION: First, a C type arc-shaped groove 12 is formed by executing groove pressing on one surface of a disk shaped base stock consisting of a material such as boron steel. Next, hole punching for forming a hexagonal hole 10 is applied to the central part using the arc shaped groove 12 as reference. Thereafter, a tooth is formed in the outer peripheral part by rough punching using the arc shaped groove 12 or the hexagonal hole 10 as reference. When the tooth is cold-forged and extruded, the tooth is formed by rough punching while guiding the base stock with an upper die 2, a knockout sleeve 4 and a hexagonal guide pin 3. Thereafter, the tooth is finished using the groove 12 and the hexagonal hole 10 (further the tooth itself) as reference. |
