Brake pressure proportioning valve.

摘要

A brake pressure proportioning valve incorporates a failure sensitive feature whereby a secondary plunger (32) is subject to pressure at a secondary inlet port (15) and assists a primary plunger (17) to overcome the load of a biassing spring (31) when pressure at the outlet port (16) reaches a predetermined magnitude. The plungers then move to allow a metering valve ball (27) to seat and prevent pressure from a primary inlet port (14) reaching the outlet port (16) without reduction. If pressure at the secondary inlet port (15) fails, this predetermined magnitude increases. The valve is made compact by arranging the secondary plunger (32) between large and small diameter portions (18 and 21) of the primary plunger.