Hydraulic pressure reducing control valve

摘要

A hydraulic pressure control valve includes a spool which has a first end having a first cross-sectional area. The opposite end of the spool has a reduced cross-sectional area. Modulated pressure is provided to a chamber at the first end of the spool and when it increases beyond the force of a biasing spring, an inlet port is connected to an outlet port. Feedback pressure acts on the differential area between a full cross-sectional area of the spool and a reduced area portion of the spool located within the outlet port. The feedback force on the spool is in proportion to the changing control force. A sleeve is provided at the end of the valve adjacent the reduced area portion of the spool, such portion and sleeve cooperating to provide a sliding seal. The outlet port will be coupled to tank whenever the modulated pressure falls below the combination of the spring force and the feedback pressure.