BALANCED POSITIONAL VALVE SPINDLE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust valve including a brake mechanism for decelerating and stopping a valve spindle in a last stage of a valve opening process, simple in structure, and high in cost efficiency in manufacturing.SOLUTION: A valve spindle of an exchange valve for a large two-stroke crosshead type uniflow diesel engine includes an actuator section 10' forming a valve actuator. The actuator section 10' includes an upper portion 14 accommodated within a central bore forming an upper part of a spindle bore. At least an elongated slit 19 is formed in a lower end of the upper portion 14. A valve operating chamber with variable volume for opening the exhaust valve is connected to a pressurized hydraulic fluid source via a hydraulic fluid passageway. The slit 19 gradually decreases a flow of the pressurized hydraulic fluid from the pressurized hydraulic fluid source to the variable-displacement-valve actuation chamber as the upper portion 14 passes through an intermediate portion of the central bore.