초록 ▼

A power steering system is disclosed which selectively controls the flow of fluid to a steering motor and an auxiliary device, and may have as its source of pressurized fluid either a fixed displacement pump, a variable displacement pump, or a load sensing pump. The system includes a steering contro

A power steering system is disclosed which selectively controls the flow of fluid to a steering motor and an auxiliary device, and may have as its source of pressurized fluid either a fixed displacement pump, a variable displacement pump, or a load sensing pump. The system includes a steering control valve disposed between the pump and the steering motor, and an externally pilot operated flow control valve, specifically, a priority valve, disposed between the pump and the steering control valve, such that the entire system flow enters the priority valve.

대표청구항 ▼

A fluid control system for selectively effecting actuation of a power steering motor to steer vehicle wheels and an auxiliary device, said system comprising: a. source of pressurized fluid; b. a steering control valve disposed in series flow relationship between said fluid source and the steering mo

A fluid control system for selectively effecting actuation of a power steering motor to steer vehicle wheels and an auxiliary device, said system comprising: a. source of pressurized fluid; b. a steering control valve disposed in series flow relationship between said fluid source and the steering motor, said steering control valve defining an inlet port and including valving movable selectively from a neutral position to right turn and left turn positions, a fluid meter including a metering element movable to measure the volume of fluid passing therethrough, and means coupling said metering member and said valving to impart follow-up movement thereto responsive to movement of said metering member; c. said steering control valve and said valving defining fluid passage means including a first variable orifice operable to establish a fluid flow rate through said passage means, a second orifice operable to establish a fluid flow direction through said fluid meter, and a third orifice disposed between said fluid meter and the steering motor; d. a flow control valve disposed in series flow relationship between said fluid source and said first variable orifice of said steering control valve, said fluid source comprising the sole source of pressurized fluid for actuation of the power steering motor and the auxiliary device, said flow control valve including an inlet port in fluid communication with said fluid source, a steering outlet port in fluid communication with said first variable orifice of said steering control valve, and an auxiliary outlet port in fluid communication with the auxiliary device; e. said flow control valve including valve means disposed to control fluid flow from said inlet port to said outlet ports, and means biasing said valve means toward a position permitting substantially all of the system flow to pass from said inlet port to said steering outlet port; f. meanns communicating a first pressure signal from immediately downstream of said first variable orifice to exert a biasing force on said valve means in the same direction as said biasing means; and g. means communicating a second pressure signal from immediately upstream of said first variable orifice to exert a biasing force on said valve means in opposition to that of said biasing means to maintain a generally constant pressure drop across said first variable orifice as said fluid flow rate varies between a minimum and a maximum.