EP0061005A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Fluid control system
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1982-02-24
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Granted: —
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Expires: 2002-02-24
Abstract
Abstract A system for controlling fluid flow from a source (10) to a steering motor (25) and one or more auxiliary motors comprises a priority valve and a steering controller. The priority valve has a housing that includes an inlet port (46) connected to the source, a priority flow outlet port (48) an auxiliary flow outlet port, and a pilot port (52). A biasing spring urges the priority valve spool toward a priority position directing all flow from the inlet port to the priority port. The priority valve includes a pilot flow conduit directing a pilot flow of fluid through an orifice to the pilot port. Pressure upstream of the pilot flow orifice acts on the priority valve spool in opposition to the spring, and pressure downstream of the pilot flow orifice acts on the valve spool in addition to the spring. The steering controller has a load sense cavity communicating with a load sense port, and a neutral vent orifice which, when the steering controller is in neutral, communicates said load sense cavity with a return port for allowing a pilot flow of fluid from the pilot port of the priority valve to flow through said steering controller to the reservoir. Upon actuation from its neutral position, the steering controller substantially restricts flow through the neutral vent orifice to the reservoir before its main flow control orifice opens. As a result, pressure at the downstream side of the pilot flow orifice of the priority valve substantially increases before the main flow control orifice opens and assists the spring to quickly urge the priority valve spool to its priority position. When the main flow control orifice is open the load sense cavity of the controller is connected to the downstream side of the main flow control orifice so that pressures across the priority valve are varied with pressure variations across the main flow control orifice in accordance with operator demand and steering load.
Inventors
- 👤 Jim Lee Rau
- 👤 Ronald Lee Lahue
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 11:09
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/07; B62D5/09; B62D5/093; B62D5/097
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
313 words
Apparatus for directing fluid flow from a source to a steering circuit having a pilot flow control means, and to an auxiliary circuit, said apparatus comprising a housing (44) having an inlet (46) for connection with the source, a priority outlet (48) for connection with the steering circuit, an auxiliary outlet (50) for connection with the auxiliary circuit, and a pilot outlet (52) for connection with the pilot flow control means in the steering circuit, a valve element (190)-movable in a valve chamber and in part defining flow passages controlling flow between said inlet and said priority outlet and between said inlet and said auxiliary outlet, means (58) biasing said valve element to a priority position directing all fluid from said inlet to said priority outlet, said valve element being movable away from said priority position in response to a predetermined net fluid pressure force thereacross, said valve element (i) gradually restricting the flow passage between said inlet and said priority outlet, and (ii) establishing and gradually increasing the flow passage between said inlet and said auxiliary outlet as it moves away from its priority position, means (62) defining a pilot conduit branching from said priority outlet said pilot conduit communicating with said pilot outlet for directing a pilot flow of fluid to said pilot outlet, said pilot conduit including a pilot orifice means (0 3 ) for producing a pressure drop in the flow of pilot fluid from said priority outlet to said pilot outlet, the downstream side of said pilot orifice means communicating with one end of said valve element, and said priority outlet communicating with the other end of said valve, element, so that the fluid pressures at the ends of the valve element can move said valve element away from said priority position when they produce a net fluid pressure force which overcomes the force of said biasing means.
Claim 2
Dependent Claim
313 words
Apparatus for directing fluid flow from a source to a steering circuit having a pilot flow control means, and to an auxiliary circuit, said apparatus comprising a housing (44) having an inlet (46) for connection with the source, a priority outlet (48) for connection with the steering circuit, an auxiliary outlet (50) for connection with the auxiliary circuit, and a pilot outlet (52) for connection with the pilot flow control means in the steering circuit, a valve element (190)-movable in a valve chamber and in part defining flow passages controlling flow between said inlet and said priority outlet and between said inlet and said auxiliary outlet, means (58) biasing said valve element to a priority position directing all fluid from said inlet to said priority outlet, said valve element being movable away from said priority position in response to a predetermined net fluid pressure force thereacross, said valve element (i) gradually restricting the flow passage between said inlet and said priority outlet, and (ii) establishing and gradually increasing the flow passage between said inlet and said auxiliary outlet as it moves away from its priority position, means (62) defining a pilot conduit branching from said priority outlet said pilot conduit communicating with said pilot outlet for directing a pilot flow of fluid to said pilot outlet, said pilot conduit including a pilot orifice means (0 3 ) for producing a pressure drop in the flow of pilot fluid from said priority outlet to said pilot outlet, the downstream side of said pilot orifice means communicating with one end of said valve element, and said priority outlet communicating with the other end of said valve, element, so that the fluid pressures at the ends of the valve element can move said valve element away from said priority position when they produce a net fluid pressure force which overcomes the force of said biasing means.
Claim 3
Dependent Claim
320 words
Apparatus as set forth in claim 1 further comprising a controller including a housing having an inlet port (34), a pair of working ports (36, 38) connected to a steering motor (25), a return port (40) connected to a reservoir (42), and a load sense port (56), said controller including directional control valve means (28) and a positive displacement follow-up metering unit (30) connected with said directional control valve means, said directional control valve means being biased to a neutral position and being movable away from said neutral position by operation of an input shaft (70) said directional control valve means defining a main flow control orifice means (0 5 ) which communicates said inlet port (34) with said metering unit (30) after a predetermined amount of movement of said directional control valve means away from said neutral position, said main flow control orifice varying in size as a function of the rate of operation of the input shaft and the load on the steering motor, said pilot conduit further including conduit means communicating said pilot outlet with said load sense port for directing a pilot flow of fluid to said load sense port of said controller, said controller having pilot flow control means including pilot flow orifice means (0 1 ) for directing the pilot flow of fluid from said load sense port through said controller and to the reservoir when said directional control valve means is in said neutral position, said directional control valve means restricting the pilot flow through said controller to the reservoir as the directional control valve means moves away from said neutral position and before said main flow control orifice establishes flow from said inlet port to said metering unit, for increasing the pressure in said pilot conduit means as said controller moves away from neutral, and producing a pressure force on said valve element for moving said valve element toward its priority position.
Claim 4
Dependent Claim
65 words
Apparatus as set forth in claim 2 including a fluid pressure cavity (64) communicating with said one end of said valve element and a biasing spring (58) disposed in said fluid pressure cavity and biasing said valve element toward its priority position, said pilot conduit directing the pilot flow of fluid through said fluid pressure cavity and to the load sense port of the controller.
Claim 5
Dependent Claim
50 words
Apparatus as defined in claim 3 wherein said pilot orifice means includes a first orifice (0 3 ) between the priority outlet and the fluid pressure cavity (64), and a second orifice (0 4 ) between the fluid pressure cavity (64) and the load sense port (56) of the controller.
Claim 6
Dependent Claim
121 words
Apparatus as set forth in any of claims 2 to 4 where said controller has a load sense cavity (68) communicated with said load sense port, said pilot flow orifice means (0 1 ) communicating said load sense cavity with said return port when said directional control valve means is in said neutral position, for directing the pilot fluid through said controller to the reservoir when the directional control valve means is in the neutral position, said directional control valve means substantially restricting flow through said pilot flow orifice means (0 1 ) to the reservoir before the main flow control orifice opens, to provide a substantial increase in pressure in the pilot conduit before the main flow control orifice opens.
Claim 7
Dependent Claim
84 words
Apparatus as set forth in claim 5 wherein said directional control valve means also communicates one side of said main flow control orifice (0 5 ) with said load sense port (56) when said main flow control orifice is directing flow from said inlet port to said metering unit, so that when said main flow control orifice is directing flow to said metering unit pressure changes due to changes in flow through said main flow control orifice affect the pressure in said pilot conduit.
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