VARIABLE VALVE TIMING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a variable valve timing device capable of improving efficiency and output of an engine by adjusting opening/closing timing of an intake valve and an exhaust valve.SOLUTION: A variable valve timing device includes: an actuator housing for providing a fixed space inside; an upper plunger internally provided in an upper part of the actuator housing so as to be elevated/lowered; a lower plunger internally provided in a lower part of the actuator housing so as to elevate/lower the upper plunger; an oil chamber provided so as to circulate or intercept oil between an upper side and a lower side of a head portion of the upper plunger, according to the elevating/lowering action of the upper plunger; and a communication channel portion for communicating an upper end portion and a lower end portion of the oil chamber according to the elevating/lowering action of the lower plunger, and adjusting a communication flow rate of the oil so as to control the elevating/lowering speed of the upper plunger.