| 摘要 |
PROBLEM TO BE SOLVED: To impart the so-called nonlinear load characteristic of suddenly increasing a load in response to an increase in load displacement in a process of opening-closing a valve, by also improving a characteristic of easily causing a bounce and a jump, possessed by a conventional single coil structure, to a degree of being not inferior to the newest double coil structure, as a valve spring of a poppet valve. SOLUTION: The fixed part side of the valve spring is wound in a relatively large diameter, and the movable part side is wound in a relatively small diameter, and that the fixed part side and the movable part side are wound in a substantially conical shape of becoming a small diameter on the movable part side, is treated as the most important characteristic, and since a pitch circle diameter of the valve spring is reduced toward the movable part side from the fixed side, a spring constant on the fixed side is reduced, and that of the movable part side is increased. That is, a nonlinear spring characteristic of heightening the spring constant to the movable part side from the fixed side is provided. COPYRIGHT: (C)2009,JPO&INPIT
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