| 摘要 |
PROBLEM TO BE SOLVED: To attain lightening of weight and improvement of mechanical strength of a retainer for an opening/closing mechanism of intake/exhaust valve driven by an electromagnetic actuator used in an internal combustion engine for an automobile. SOLUTION: An electromagnetic actuator 4 is stored in a housing 8 mounted in an internal combustion engine main unit 19, a tip end part of a first stem 15 and a tip end part of a valve 9 are butt placed, a retainer 13 is provided in the valve 9, and a first return coil spring 2 is mounted, a second stem 14 is provided in a surface in an opposite side to a surface of an armature 3 provided with the first stem 15, additionally a retainer 13 is provided in the second stem 14, a second return coil spring 1 is mounted between this retainer 13 and the housing 8, at least one of each of these parts is formed of metal or its alloy and the like having specific gravity smaller than that of iron. A corner part 13d from a spring contact surface 13c of the retainer 13 to a boss side surface is formed as a circular arc surface, to relax concentration of stress. Curvature R of the circular arc surface is set to 1.0 mm or more.
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