| 摘要 |
PURPOSE: A 3-stage pressure control valve is provided to make more precise control possible by controlling pressure in three stages. CONSTITUTION: A 3-stage pressure control valve contains: a sleeve(10) having a working fluid inflow passage and a drain passage; a poppet(20) inserted to the sleeve to open and close the working fluid inflow passage; a first elastic member(30) supporting the poppet elastically against the opening direction of the poppet; a pilot poppet(40) opened to drain working fluid to a hydraulic tank through the drain passage if high pressure over the preset pressure occurs in a pressure chamber of the sleeve; a first piston(50) slid in the poppet and contact with the pilot poppet by the initial pressure of working fluids discharged from the hydraulic pump; a second elastic member(60) supporting the first piston elastically; a third elastic member(70) supporting the pilot poppet elastically against the opening direction of the pilot poppet; a second piston(80) supporting the third elastic member elastically and tensing the third elastic member; a fourth elastic member(90) supporting the second piston; a first control plug(100) pressurizing the second piston to keep at the preset pressure; a third piston(110) installed in the first control plug; a fifth elastic member(120) supporting the third piston; and a second control plug(130) pressurizing the third piston to keep at the preset pressure.
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