PILOT-TYPE RELIEF VALVE

摘要

PURPOSE:To suppress the imbalance of pressures at the both edges of a main spool due to the tapered surface by forming a variable throttle part in which the throttle area is varied according to the displacement of the main spool. CONSTITUTION:A pressure port 34 is opened onto a valve opening 33 at the position separated in the axial direction from an exhaust port 35. The both chambers of a main spool 36 communicate each other through an orifice 37. When the differential pressure between before and behined the orifice 37 overwhelms the springy force of a spring 39, the main spool 36 moves in slidable ways to open the tapered surface 33b. Therefore, a variable throttle part 40 in which the throttle area is increased by the tapered surface 33b and the main spool 36 as the displacement of the main spool 36 increases is formed.