| 摘要 |
PROBLEM TO BE SOLVED: To prevent erosion by cavitation to a timer piston 16 and reduce tensile stress generated in an opening circumferential edge part 17a of a recess part 17 by driving reaction in displacement of a face cam. SOLUTION: The timer piston 16 is provided with a guide passage 20 guiding fuel to the recess part 17 and a discharge passage 21 discharging the fuel from the recess part 17 to the inside of the timer casing 15 and a fitting part of a sub piston 40 for inserting a slide pin 19 is formed with an annular groove 22 communicating the guide passage 20 with the discharge passage 21 and releasing the fuel from the recess part 17. When the driving reaction is applied to the sub piston 40 via the slide pin 19, the fuel in the recess part 17 releases to outside the recess part 17 via the annular groove 22 to suppress alternate generation of a negative pressure and a high pressure in the fuel in the recess part 17 so that the erosion caused by the cavitation to the timer piston 16 can be prevented.
|
