Abstract: An anti-saturation valve assembly (51) for use in a hydraulic system having priority (17) and auxiliary (25) load circuits, the priority circuit providing a priority load signal (19). The anti-saturation valve assembly includes a pressure sensor portion (61) which senses a decrease between pump pressure (23) and the priority load signal (19), and generates a force on a pressure reducing portion (63) to reduce, correspondingly, a pilot pressure (59): The reduced pilot pressure to a pilot valve (35) results in reduced flow to a pilot-operated main control valve (27) in the auxiliary load circuit (25), thus providing anti-saturation protection for the circuit, without throttling a main flow path and wasting substantial hydraulic power.

Abstract: A solenoid assembly (23) includes a coil assembly (65) having at least one coil winding (73) and an electronic circuit assembly (67), which is in electrical communication with the coil assembly (65). The electronic circuit assembly (67) has a printed circuit board (79) and at least one electronic component (81), which is surface mounted on the printed circuit board (79). A coating material (85) coats all of the plurality of external surfaces of the surface-mounted electronic component (81). A casing (87) over-molds an outer longitudinal surface (77) of the coil assembly (65) and all of a plurality of external surfaces of the electronic circuit assembly (67).

Abstract: A rotary fluid pressure device (11) includes a plate assembly (17) having a plate member (71) and at least one cover plate (105), which defines a mounting surface (107) adapted for sealing engagement with an exterior surface (77) of the plate member (71), or at least one control valve assembly (105), which defines a mounting surface (117) adapted for sealing engagement with the exterior surface (77). The cover plate assembly (105), when mounted to the exterior surface (77), provides fluid communication between openings (95, 97) of upstream and downstream fluid passages (91, 93), thereby providing single-speed functionality. The control valve assembly (115), when mounted to the exterior surface (77), provides selective fluid communication between the openings (95, 97) of upstream and downstream fluid passages (91, 93), thereby providing multi-speed functionality.

Abstract: A cap for a fluid coupling is provided that includes a stem member adapted for insertion into the fluid coupling and a cover member connected to the stem member. The cover member includes an internal cavity sized to receive the fluid coupling such that the fluid coupling is positioned between the stem member and the cover member. The internal cavity is defined by a wall having at least one of a longitudinally extending groove and a longitudinally extending protrusion.

Abstract: A fitting is provided that includes a receptacle having an inner wall forming a female member. The inner wall includes a shoulder and a land. A male member is received in the female member with a gap therebetween. The male member includes an outwardly opening groove. An O-ring is seated between the outwardly opening groove in the male member and the shoulder and the land of the receptacle to prevent removal of the male member from the receptacle. The outwardly opening groove, the shoulder and the land are configured such that compression of the O-ring is sufficient to prevent removal of the male member from the female member.

Abstract: A rotary fluid pressure device (11) has a stationary valve member (17), a rotatable valve member (51), and a valve seating mechanism (73). The valve seating mechanism (73) defines an outer balance ring member (75) having a valve-confronting surface (79) in engagement with an opposite surface (81) of the rotatable valve member (51) and an inner balance ring member (77) having a valve-confronting surface (111) in engagement with the opposite surface (81) of the rotatable valve member (51), with the outer balance ring member (75) and the inner balance ring member (77) being structurally independent from the other. The outer balance ring member (75) and the inner balance ring member (77) define a balance ring passage (71) which provides continuous fluid communication between a fluid inlet (53) or a fluid outlet (53) and the valve passages (61) in the rotatable valve member (51).

Abstract: A method for estimating actuator position includes the steps of receiving fluid pressure data signals from a plurality of fluid pressure sensors (31), receiving spool position signals from at least one spool position sensor (33), and receiving actuator position data signals from at least one actuator position sensor (35). Corrected flow rates to and from an actuator (21) are determined with each corrected flow rate being based on fluid pressure data signals, the spool position signals, and an error-correction factor, wherein the error-correction factor is a function of the fluid pressure data signals and the spool position signals. An estimated actuator position is determined wherein the estimated position includes a kinematic component and a dynamic component. Adaptive gain factors are applied to calibrate the estimated actuator position to the actuator position data signals from the actuator position sensor.

Abstract: A manually actuated cartridge valve assembly (15) has a main body (31), a valve assembly (33), and an end assembly (35). Disposed within an internal cavity (107) of the end assembly (35) is a rotary member (109) that rotates about an axis (115) when a handle (29) is manually actuated. The axis (115) is substantially perpendicular to the axis (73) of the spool valve (49). The rotary member (109) has at least one axial end (117) that extends through the outer surface of the end assembly (35) and attaches to the handle (29). The movement of the handle (29) defines a plane of movement (147), which is selectively rotatable about the axis (73) to a desired orientation (149). A locking member (99) is selectively operably associated with the end assembly (35) to restrict rotation of the plane of movement (147).

Abstract: A fluid controller (15a) in a multiple-input hydrostatic power steering system includes a check valve assembly (101), having a first fluid passage (111), defining a check valve seat (105) and a check valve (103) operably associated therewith, in fluid communication with a second fluid passage (109), with the second fluid passage (109) being in fluid communication with a return port (25a). In the left (L) and right (R) operating positions, return flow can flow from the interior region (114) of the valve (27), through the first fluid passage (111), past the check valve (103), and through the second fluid passage (109) to the return port (25a). In the neutral position (N), pressurized fluid can flow from an inlet port (19a) to the return port (25a), with the check valve (103) preventing fluid from flowing through the first fluid passage (111) and into the interior region (114) of the valve (27).

Abstract: A hydraulic drive system (11) of the type including a hydrostatic pump-motor unit (35) having a pumping mode in which the unit pressurizes, from its port (A), a high pressure accumulator (41), and a motoring mode, in which the unit is driven by pressurized fluid from the high pressure accumulator. The system also includes a low pressure accumulator (39) in communication with the opposite port (B) of the pump-motor unit (35), and a filter circuit (107) disposed therebetween. The filter circuit (107) defines an unrestricted first flow path from the low pressure accumulator to the port (B) when the unit is in the pumping mode, and a second flow path from the port (B) to the low pressure accumulator when the unit is in the motoring mode. The second flow path comprises one path portion (125) through a filter shut-off valve (121) and a filter (127) in series, and in parallel therewith, another path portion through a controlled flow restriction (135).

Abstract: A rotary fluid pressure device defining a fluid inlet (17), an output shaft (37), and a housing (41,43) defining a brake chamber (61), a piston member (63,65) being disposed therein and biased toward an engaged position by a spring (69). Braking means (57,59) is associated with the piston and the output shaft, such that movement of the piston to the engaged position results in braking of said output shaft. The housing defines a fluid pressure port (73) in communication with the fluid inlet, and the piston defines a large pressure release chamber (71) in fluid communication with said fluid pressure port. The piston defines a small pressure release chamber (89) also in fluid communication with the fluid pressure port. A valve means (75,81) is operable, when fluid pressure in the large release chamber reaches a predetermined pressure, to communicate the large to a source of low pressure fluid.

Abstract: An HST propel system includes first and second pumps having displacements variable in response to movement of first (31) and second (33) control shafts, respectively; and a linkage arrangement for moving the control shafts in unison in response to movement of an operator input (37). The linkage arrangement comprises a crank arm (35) rotatable about its axis in response to movement of the input device, first (41) and second (51) input arms fixed relative to the crank arm, and first (45) and second (55) elongated control rods pivotally connected to the input arms. The system includes a swivel connector (43) cooperating with its input arm to define a swivel axis (S.A.1), fixed relative to the axis of the crank arm, and a swivel connector (53) cooperating with its input arm to define a swivel axis (S.A.2), moveable relative to the axis of the crank arm for straight tracking adjustment.

Abstract: A relief valve assembly (27) for use with first (15) and second (21) conduits, one communicating high pressure. The assembly comprises a housing (29,33) defining first (45) and second (47) ports, and a poppet seat (49). A poppet member (43) and the housing define a spring chamber (55), and a spring (39) is disposed to bias the poppet member toward the seat. The poppet member defines a shuttle cavity (51), a shuttle passage (53) communicating from the cavity to the spring chamber, and the poppet defining a seat (57), and a fluid passage (61P) communicating with the first port, and a seat (59), and a second fluid passage (63) communicating with the second port. A shuttle valve assembly (71,73,75) is provided, whereby the fluid pressure in whichever of the ports is at lower pressure is communicated to the spring chamber and adds to the force of the biasing spring.