| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact balance piston type relief valve also reduced in cost. SOLUTION: This balance piston type relief valve comprises a valve body 1 in which a piston hole 2 is formed. A primary pressure port A is allowed to communicate with one end of a hole 2, and a secondary pressure port B is allowed to communicate with the peripheral surface of the hole 2. A main piston 4 forming the main valve is stored in the hole 2, energized by a main spring 7, and made to abut on a valve seat 3 at one end of the hole 2 to cut out the port A from the port B. The piston comprises a pilot passage 11 having an orifice 10 allowing the port A to communicate with the main spring chamber 6 formed at the other end of hole 2, a first passage 12 communicating with the main spring chamber, and a second passage 13 communicating with the port B. A spool hole 8 opening to the port A is formed at the axis of the piston, and a pilot spool 14 forming the pilot valve is stored in the hole 8. The spool comprises a communication passage 18 allowing the passage 12 to communicate with the passage 13, energizes the spool in the port A direction by the pilot spring 19 to cut out the passage 12 from the passage 13. COPYRIGHT: (C)2005,JPO&NCIPI
|
