| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a piston type pressure reduction valve reduced in capacity of a back pressure chamber to a minimum requirement, and excellent in responsiveness and secondary pressure stability with respect to transitional change in primary pressure, flow rate and others. <P>SOLUTION: A piston type pressure reduction valve comprises: a piston 20 sliding in a housing 2 in an axial direction and having a sheet part 21 for closing a valve seat port 10 of a primary port 3; a primary pressure chamber 6 and a secondary pressure chamber 8 partitioned by the piston 20; a valve chamber 7 formed so as to communicate with the primary pressure chamber 6 and the secondary pressure chamber 8; and a rod 12 fitted into the piston 20 from a side of the secondary pressure chamber. The piston 20 has a fitting hole 30 into which the rod 12 is fitted and a communication hole 32 formed so as to communicate the fitting hole 30 with the primary pressure chamber 6. The fitting hole 30 has a concave seal groove 36 formed in a portion facing the fitted rod 12, and a back pressure chamber 31 formed in the piston 20 by sealing between the rod 12 and the piston 20 by using a seal member 37 provided in the seal groove 36. <P>COPYRIGHT: (C)2013,JPO&INPIT |
