Abstract: A fluid controller (27) for use with a fluid pressure operated device (45) having an inlet (47) and an outlet (49) and defining a fluid leakage path therebetween. The controller (27) includes valving (61) defining a main fluid path and further defines a fluid bleed passage including a variable bleed orifice (AB), having a substantially zero flow area when the controller valving (61) is in its neutral position (N) and in the normal operating position (R), but beginning to open as the valving approaches its maximum displacement position (R-M).

Abstract: A fluid controller (27) for use with a fluid pressure operated device (45) having an inlet (47) and an outlet (49) and defining a fluid leakage path therebetween. The controller (27) includes valving (61) defining a main fluid path and further defines a fluid bleed passage including a variable bleed orifice (AB), having a substantially zero flow area when the controller valving (61) is in its neutral position (N) and in the normal operating position (R), but beginning to open as the valving approaches its maximum displacement position (R-M).

Abstract: A fluid controller (27) for use with a fluid pressure operated device (45) having an inlet (47) and an outlet (49) and defining a fluid leakage path therebetween. The controller (27) includes valving (61) defining a main fluid path and further defines a fluid bleed passage including a variable bleed orifice (AB), having a substantially zero flow area when the controller valving (61) is in its neutral position (N) and in the normal operating position (R), but beginning to open as the valving approaches its maximum displacement position (R-M).

Abstract: A fluid controller (17) to control flow to a steering cylinder (19) is modified to include a selector valve assembly (41,73) having two operating positions. In a first position (“R” in FIG. 1), the selector valve (73) permits fluid flow though the main fluid path (53) in the normal manner, as would be used when the vehicle is in a “roading” mode. In a second position (“W” in FIG. 1 and in FIG. 3), the selector valve (73) blocks flow through the fluid meter (43) which normally provides the follow-up movement (51) to the controller valving (31,33), and bypasses the fluid meter in a “working” mode. Thus, the normal flow rate can be achieved by merely rotating the steering wheel (27) an amount which corresponds to the desired deflection of the controller valving (31,33), without the need for the continuous rotation of the steering wheel, as required during normal steering.

Abstract: A fluid controller (15) of the type which controls the flow of fluid to an unequal area steering cylinder (25), wherein the controller is of the load reaction type. The controller (15) includes valving (27) which, when it is in neutral (FIGS. 1 and 5), defines a load reaction fluid path (LR) permitting fluid communication between the control fluid ports (21, and 23) through the fluid meter (29) in response to an external load imposed on the cylinder (25). In accordance with the invention, the valving (27) includes a fluid path (97,95,99,71,75) between the load reaction fluid path (LR) and the return port (19), when the valving is in neutral. When the rod end chamber (A) is contracting, fluid is drawn from the return port into the load reaction fluid path (LR), preventing cavitation, and when the head end chamber (B) is contracting, fluid flows from the load reaction fluid path (LR) to the return port (19), preventing pressure intensification.

Abstract: A controller (11) and a system for controlling the flow of fluid to a fluid pressure operated device (C) are disclosed. The controller is of the type including a rotatable spool valve (35) and a relatively rotatable sleeve valve (37). Relative rotation between the spool and sleeve define a main fluid path (MFP) and relative axial movement therebetween defines an auxiliary fluid path (AFP). An actuator (65) generates a mechanical output (71) in response to an electrical input signal (CS) to move the sleeve (37) between its neutral axial position (FIG. 6) and an axial operating position (FIG. 7). Axial movement of the sleeve is controlled by a joystick (J). The system includes various sensors (S,PS,G,P), which can sense a predetermined condition and generate an interrupt signal to interrupt or change the gain of the electrical input signal (CS).

Abstract: A torque-generating steering device is provided for use with a pump (19) having a pressure compensator (23) for varying the output of the pump. The device includes a gerotor displacement means (43) which provides a relatively high-torque output to an output shaft (29) in response to the flow of fluid through the gerotor. A spool valve (73) and sleeve valve (75) define a fluid path (119) from an inlet port (13) through the gerotor to an outlet port (15). The fluid path includes a main variable flow control orifice (121) in series flow between the inlet and the gerotor, the orifice having a zero flow area when the spool and sleeve are in their neutral position, and a maximum flow area when the spool and sleeve are in an operating position. The device defines a load-sensing port (115) communicating with the pressure compensator (23) and with the fluid path (119), downstream of the orifice (121).

Abstract: A fluid controller (15) is disclosed for controlling the flow of fluid to fluid pressure operated devices such as a vehicle steering cylinder (17). The controller is of the type including a valve spool (35) and a valve sleeve (37) in which the various ports, passages and fluid paths are non-symmetrical. Metered, pressurized fluid is communicated through axial slots (85) in the valve spool and is communicated through cylinder ports (73) for a right turn condition, or through cylinder ports (75) for a left turn condition. The right turn cylinder ports (73) are located further axially than are the left turn cylinder ports (75) from the end of the spool and sleeve which communicate with the return port. As a result, metered, pressurized fluid has a longer leakage path for a right turn than for a left turn.

Abstract: A fluid controller (15) is provided of the type for directing pressurized fluid from a source (13) to a steering cylinder (17). The controller includes a housing defining right and left turn ports (32 and 34) and corresponding annular grooves (32g and 34g). The controller valving includes a cylindrical sleeve (37) and a spool (35). Steering against the cylinder stops results in trapped pressurized fluid in one of the annular grooves (32g or 34g) after the valving returns to the neutral position. The sleeve (37) is provided with pressure balancing passages (93 and 97) which are positioned to communicate trapped pressurized fluid into pressure balancing areas (85 or 99, respectively). The pressurized fluid in the balancing areas is able to counteract the clamping force on the sleeve resulting from the trapped fluid in one of the annular grooves (32g or 34g), and thereby prevent a subsequent stiction condition when the vehicle operator attempts to begin the next steering maneuver.

Abstract: An improved fluid controller (17) is disclosed of the type for use in a load sensing hydrostatic steering system. The system includes a load sensing priority flow control valve (15) of the type which operates on a dynamic load signal. The controller includes a spool valve (95) and a sleeve valve (97) which cooperate to define a plurality of orifices including a main variable flow control orifice (71) and a variable orifice (75) through which fluid flows from the return side of a steering cylinder (19) to the return port (25) of the controller. A variable drain orifice (76) communicates between the main flow path, downstream of the main orifice (71) and the return port (25). As the controller valving moves from its neutral position toward an operating position, the orifice (75) begins to open at least as soon as the main orifice (71) and reaches a predetermined flow area before the main orifice (71) reaches that predetermined flow area.