| 摘要 |
PURPOSE:To facilitate machining of a valve retainer and to ensure mounting of a valve head to the valve retainer, by a method wherein the valve retainer is formed into a cylinder body having an inner wall part for securing by the use of a plate body, and the inner wall part is secured to the valve retainer. CONSTITUTION:A valve stem 4 has an umbrella part 4b at its lower part seated to a valve seat 3 and a head 4a at its upper part located to the open end of a recess part 1a of a cylinder head 1. In which case, the head 4a is engaged with a valve retainer 5, formed into a cylinder body having an inner wall part 5b for securing, to spot-weld the two parts 4a and 5b. Thereby, the retainer 5 is formed such that, after a cylinder part 51 with a bottom, is press-drawn to a circular blank of a steel plate and is drawn to form a hole 52 in the bottom part, burring processing is made through utilization of the hole 52 to form the inner wall part 5b. Thereafter, redrawing press processing is applied to form an outer wall part 53. |
