| 摘要 |
PURPOSE:To make the auxiliary piston return in position previous to the seating of a valve by a method wherein the pressure of a highly pressurized air pressing the auxiliary piston of a hydraulic shock absorbing part communicated with a hydraulic operating line which opens or closes an exhaust valve is made to overcome a valve spring pressure. CONSTITUTION:A cylinder chamber 29 of a hydraulic shock absorbing part is opened to a hydraulic communicating pipe 13 which opens and closes an exhaust valve via a communicating passage 27. An auxiliary piston 30 is fitted into a cylinder chamber 29, a high pressure air chamber 33 is formed at the back of the auxiliary piston 30. The high pressure air chamber 33 is continuously supplied with a high pressure air having the pressure stronger than that of a valve spring of the exhaust valve. In such a manner, the auxiliary piston 30 returns in position previous to the seating of the exhaust valve, accordingly, the exhaust valve gradually seats without collision. |
