| 摘要 |
A simplified intake/exhaust valve assembly for an internal combustion engine which has a change-over operation of operative and inoperative state of the intake/exhaust valve is provided. The intake/exhaust valve assembly comprises a reciprocating valve having a valve stem and a valve head placed at a position at which an inlet/exhaust port opens into a power cylinder of the engine, to open and close the inlet/exhaust port in accordance with an axial movement thereof, a camshaft driven by a crankshaft of the engine, having a cam surface formed on the circumferential surface thereof, a cam follower having a first end associated with an end of the valve stem, a second end which forms a supporting point thereof, and a bearing surface contactable with the cam surface of the cam shaft, the cam follower being adapted to translate a rotation of the camshaft into the axial movement of the reciprocating valve so as to open and close the inlet/exhaust port in accordance with the rotation of the camshaft when the cam follower is made operative, and a support means comprising, a piston plunger having a head portion for supporting the second end of the cam follower, a cylindrical member for slidably receiving the piston plunger and having a hydraulic pressure chamber formed therein, and a retainer member for slidably receiving the cylindrical member, the cylindrical member being axially slidable in the retainer member between predetermined first and second positions in which the cam follower is made operative and inoperative respectively.
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