| 摘要 |
<p>A variable valve gear for an internal combustion engine, capable of changing the operating characteristics of an engine valve according to a change in the rotational frequency of the camshaft. A high-speed cam (60) having a high section which has a base circle section having the same radius as the base circle section of a low-speed cam (59) and has a greater amount of projection than a high section of the low-speed cam (59) is supported by a camshaft (43A), to which the low-speed cam (59) is secured, at a position adjacent to the low-speed cam (59). A cam follower member (46) is supported by an engine body (11) so as to be able to operate by following either the low-speed cam (59) or the high-speed cam (60). A centrifugal clutch (61A) for connecting, when the rotational frequency of the camshaft (43A) becomes higher than or equal to a predetermined rotational frequency, the high-speed cam (60) to the camshaft (43A) while matching the phase of the high-speed cam (60) to the phase of the low-speed cam (59) is provided between the camshaft (43A) and the high-speed cam (60). Thus, the operating characteristics of the engine valve can be changed using a simple and compact structure.</p> |
