Patent ID: 6173728
Filing Date: 2001-01-16
Classification: B62D,Y10T

Abstract:
Apparatus for use with a primary pump, an auxiliary pump, and a steering control valve, said apparatus comprising:a switching valve including a longitudinally movable valve spool and a spring biasing said spool to a neutral position, said switching valve being configured to direct hydraulic fluid from the primary pump to the control valve when said spool is in a primary position and to direct hydraulic fluid from the auxiliary pump to the control valve when said spool is in an auxiliary position;said spool being movable against a bias of said spring from said neutral position to said primary position under the influence of a hydraulic fluid pressure differential between opposite ends of said spool;said switching valve defining a flow path for directing hydraulic fluid from the primary pump to an end of said spool when said spool is in said neutral position, said flow path extending axially over a flat portion of an outer surface of said spool.