| 摘要 |
<p>PURPOSE:To make a smooth changeover possible, by providing a separately a shift cam mechanism and shifter forks selecting valve system cams, and conducting the cam changeover by moving a cam block at the time when the perimeter edge portion of the valve system cams is not located at the top portion side part territory of a valve. CONSTITUTION:A cam block 2 made up of low speed and high speed cams 3,4 provided in parallel integrally, is put with a spline on a cam shaft 1. A cam projection for shifting, 5 which is of a circular arc and which projects in an inclining shape on the lift portion 4a side of the high speed cam 4, is formed on the side end surface of the high speed cam side of the cam block 2. Also, guide shafts 6,20 are provided at the upper and lower parts of the cam shaft 1 in parallel with th shaft 1, and a slide block 7 having an arm portion 9 provided with a finger portion 8 which is freely engaged with the cam projection 5, is put idlingly on the guide shaft 6, and a shift cam mechanism 100 is made. Also, a shifter block 21 having shifter forks 22a,22b is put idlingly on the guide shaft 20, and respective blocks 7,21 are driven by means of a common motor 11.</p> |
