| 摘要 |
<p>PROBLEM TO BE SOLVED: To ensure a smooth changeover motion by installing a changeover rod, being shiftable in the axial direction, corresponding to each cylinder, and pushing each of selector pins dividedly set up, in a camshaft and energizing this changeover rod in the lower speed direction at all times, while switching the changeover rod at each cylinder successively when a valve is inoperative. SOLUTION: A selector valve 32 is controlled by a control unit 40, and in time of high speed, it feeds two hydraulic chambers 20 and 21 with oil from an oil supply pipe 35, and a changeover rod 13 is shifted to the high speed side against a spring 26. If so, each selector pin 14 is shifted to the high speed side by dint of a cam part 13a, and thereby each of keys 11 and high speed cams 10 is advanced in the longitudinal direction, performing a changeover to these high speed cams 10. When the selector valve 32 is switch to the low speed side and a supply of oil is stopped in time of low speed, each hydraulic pressure in both these hydraulic chambers 20 and 21 goes down so that the changeover rod 13 is shifted to the low speed side by dint of the spring 26. If so, each selector pin 14 is shifted to the low speed side as well by each cam part 13a, whereby the keys 11 and the high speed cams 10 are retreated in the longitudinal direction, performing a changeover to each low speed cam 9.</p> |
