| 摘要 |
PURPOSE:To damp the impact of intake and exhaust valves and a piston, by limiting the discharge of oil from hydraulic chambers so that the speeds of the piston and the valves just before the termination of the piston are restrained. CONSTITUTION:An intake or exhaust valve 27 is opened and closed in association with the movement of a piston 23 disposed in a cylinder 21. A hydraulic selecting means 45 in response to a solenoid valve 44 controls hydraulic pressure fed to first and second hydraulic chambers 24, 25 defined in the cylinder 21 by the piston 23. Passages 31, 30 are closed by the piston 23 just before the terminations of valve opening and closing movements, respectively, so that oil from the hydraulic chambers 25, 24 is discharged through damper passages 37, 33 which limit the flow rate of oil to a lower value. Accordingly, the moving speed of the piston 23 decreases so that impact upon the termination of its movement is damped. |
