Hydraulic valve with pressure limiter
AssigneeParker-Hannifin Corporation
InventorGregory Coolidge
Life of this patent
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Abstract
An assembly of valve sections includes an inlet section, an outlet section, a working section, and a working section. The working section is a conventional pressure compensated working section. The working section includes a directional control valve, a pressure compensator valve, and a pressure limiter valve. The valves are of integral construction, such that each is an essential part to complete the other. The pressure compensator valve includes a pressure compensator spool movable between an opened position and a closed position in response to a pressure differential across the spool. The pressure limiter valve includes a pressure limiter spool that moves to an open position to change the pressure differential and close the pressure compensator valve when a selected limit pressure is reached.
Claims21
An integral pressure compensator valve and pressure limiter valve comprising:
- a fluid flow path;
- a pressure compensator valve and a pressure limiter valve disposed in said fluid flow path and dividing said fluid flow path into an upstream side and a downstream side;
- a pressure compensator spool carrying a pressure compensator valve surface, said pressure compensator valve surface being movable with said pressure compensator spool and defining a variable area fluid orifice in said fluid flow path;
- a pressure limiter spool carrying a pressure limiter valve surface, a pressure limiter passage, said pressure limiter valve surface being movable longitudinally with said pressure limiter spool to open and close said pressure limiter passage, and
- a housing for the fluid flow path, the pressure compensator valve and the pressure limiter valve, the housing having a first spool bore and the pressure compensator spool and the pressure limiter spool are disposed in the first spool bore,
- wherein the pressure compensator spool includes a second spool bore, and the pressure limiter spool is slidably disposed in the second spool bore and is carried by the pressure compensator spool.
A working section for a valve assembly comprising:
- a valve body having an inlet core, a spool gallery with a reduced fluid pressure that is less than the fluid pressure of the inlet core, and at least one work port;
- a spool extending through at least a portion of the valve body and being movable relative to the valve body for controlling fluid flow from the inlet core to the spool gallery;
- a compensator valve having a compensator spool separating the spool gallery and the at least one work port, the compensator valve being biased into a closed position and opening for regulating flow between the spool gallery and the at least one work port;
- and
- a pressure limiter for limiting the pressure provided to the work port to a predetermined value, the pressure limiter operable to move the compensator valve toward the closed position when the work port pressure meets or exceeds the predetermined value by connecting fluid passages to direct the reduced fluid pressure from the spool gallery to an opposite end of the compensator spool.
An integral pressure compensator valve and pressure limiter valve comprising:
- a fluid flow path;
- a pressure compensator valve and a pressure limiter valve disposed in said fluid flow path and dividing said fluid flow path into an upstream side and a downstream side;
- a pressure compensator spool carrying a pressure compensator valve surface, said pressure compensator valve surface being movable with said pressure compensator spool and defining a variable area fluid orifice in said fluid flow path;
- and
- a pressure limiter spool carrying a pressure limiter valve surface, a pressure limiter passage, said pressure limiter valve surface being movable with said pressure limiter spool to open and close said pressure limiter passage when a limit fluid pressure in the downstream side of the fluid flow path reaches a selected pressure level,
- said pressure compensator valve surface exposed to said upstream side to urge said pressure compensator spool toward an opened position to open said variable orifice,
- said pressure limiter passage establishes fluid pressure communication between the upstream side of said fluid flow path and at least one pressure compensator spool closing radial surface area for urging said pressure compensator spool closed when said limit fluid pressure reaches a selected pressure level.
Dependencies are inferred from the claim text.