Pressure modulating selector valve
AssigneeCaterpillar Tractor Co.
InventorHugh C. Morris
Life of this patent
Estimating the term…
Abstract
A selector valve selectively communicates pressurized fluid from an inlet to an outlet and is adapted to be connected to a clutch of a transmission. The selector valve comprises a spool normally blocking communication between the inlet and outlet, a selector piston responsive to a control signal for movement towards the spool and a load piston reciprocally mounted in the selector piston and adapted to be moved thereby to control movements of the spool. A modulating orifice is interconnected between the outlet and the load piston to control movements of the spool for modulating fluid pressure in the outlet to a predetermined level.
Claims16
A pressure modulating selector valve having an inlet, an outlet and a drain and comprising
- first means within said valve for movement in a first direction between a closed position blocking communication of fluid from said inlet to said outlet to an open position communicating fluid from said inlet to said outlet, said first means providing communication between said outlet and drain in the closed position and preventing communication between said outlet and drain in an open position,
- second means responsive to a fluid pressure pilot control signal for movement in said first direction towards said first means to a limit stop position,
- third means responsive to movement of said second means in said first direction for moving said first means to its open position through an interposed means to communicate said inlet with said outlet and closing said drain, and
- modulating means interconnected between said outlet and said third means for controlling gradual further movement of said first means through its open position in response to movement of said third means to modulate the increase of fluid pressure in said outlet to a predetermined level.
A pressure modulating selector valve having an inlet and an outlet and comprising
- valve means for sequential movement in a first direction from a first position blocking communication between said inlet and said outlet, to a second position partially communicating said inlet with said outlet, and to a third position for fully communicating said inlet with said outlet, and
- control means for sequentially moving said valve means from its first position to its second position and for then gradually modulating movement of said valve means from its second position to its third position, said control means comprising selector piston means for moving in said first direction towards said valve means in response to a control signal to a limit stop position, load piston means for moving said valve means through an interposing means from its first position to its second position and towards said third position in response to movement of said selector piston means, and modulating means interconnected between said outlet and said load piston for controlling gradual movement of said load piston means and simultaneous gradual movement of said valve means from its second position to its third position in response to fluid pressure in said outlet.
Dependencies are inferred from the claim text.