One example provides a ride on air injection machine including one or more steerable wheels, a compressed air system providing compressed air, one or more air inject tines to inject compressed air from the compressed air system into the grounds, and a steering system. The steering system includes a steering wheel, a cylinder coupled to the steerable wheels, the cylinder including opposing internal chambers and being moveable to steer the steerable wheels and a control valve assembly to direct compressed air from the compressed air system to the internal chambers and to bleed compressed air from the internal chambers based on a position of the steering wheel to move the cylinder steer the steerable wheels.

An autonomous steering control unit for a hydraulic steering control system has a pilot selector valve, primary and secondary electro-hydraulic (EH) steering valves, and an output selector valve. In a primary autonomous steering mode, the primary EH steering valve operates to output pilot fluid from the pilot selector valve through the output selector valve to the steering control system to control steering of a work machine while the pilot selector valve and the output selector valve isolate the secondary EH steering valve from the steering control system. In a secondary autonomous steering mode, the secondary EH steering valve operates to output pilot fluid through the output selector valve to the steering control system while the primary EH steering valve is isolated from the steering control system. In alternative embodiments, a load sense selector valve alternately connects an dynamic load sense line to the operative steering valve.

An autonomous steering control unit for a hydraulic steering control system has a pilot selector valve, primary and secondary electro-hydraulic (EH) steering valves, and an output selector valve. In a primary autonomous steering mode, the primary EH steering valve operates to output pilot fluid from the pilot selector valve through the output selector valve to the steering control system to control steering of a work machine while the pilot selector valve and the output selector valve isolate the secondary EH steering valve from the steering control system. In a secondary autonomous steering mode, the secondary EH steering valve operates to output pilot fluid through the output selector valve to the steering control system while the primary EH steering valve is isolated from the steering control system. In alternative embodiments, a load sense selector valve alternately connects an dynamic load sense line to the operative steering valve.

A pneumatic steering system includes a cylinder movable in relation to a through rod, steering tie rods coupled to the cylinder, a control valve that controls motion of the cylinder in relation to the through rod, a spring-biased pivoting actuator operably coupled to a steering linkage and to a control input of the control valve. The actuator is pivotally mounted to a structure attached to the cylinder. The control valve is attached to that structure. The steering linkage is an articulated assembly that transforms rotation of the steering column into pivoting movement of the actuator.

A fluid controller (1), in particular as part of a hydraulic steering unit, is described said controller (1) comprising a housing (2) having a supply port arrangement, a sleeve (4) arranged rotatably in a bore of the housing (2), a spool (3) arranged rotatably in the sleeve (4), and a measuring motor, wherein the measuring motor comprises a plurality of working chambers, each working chamber being connected to the bore, wherein the sleeve (4) comprises a commutation geometry (7) having a first partition and controlling together with a housing geometry (5) of the housing (2) a flow of hydraulic fluid into and out of the working chambers and the spool (3) comprises a spool geometry (14) controlling together with a valve geometry (10, 11) of the sleeve (4) a flow of hydraulic fluid between the supply port arrangement and the commutation geometry. Such a fluid controller should have a stable control behavior. To this end the valve geometry (10,11) comprises a second partition different from the first partition.

A fluid controller (1), in particular as part of a hydraulic steering unit, is described said controller (1) comprising a housing (2) having a supply port arrangement, a sleeve (4) arranged rotatably in a bore of the housing (2), a spool (3) arranged rotatably in the sleeve (4), and a measuring motor, wherein the measuring motor comprises a plurality of working chambers, each working chamber being connected to the bore, wherein the sleeve (4) comprises a commutation geometry (7) having a first partition and controlling together with a housing geometry (5) of the housing (2) a flow of hydraulic fluid into and out of the working chambers and the spool (3) comprises a spool geometry (14) controlling together with a valve geometry (10, 11) of the sleeve (4) a flow of hydraulic fluid between the supply port arrangement and the commutation geometry. Such a fluid controller should have a stable control behavior. To this end the valve geometry (10,11) comprises a second partition different from the first partition.

The invention relates to a hydraulic steering unit (1) including a housing (3), a spool, a sleeve (12) arranged between spool and housing (3), and a measuring motor (14) having a number of working chambers (15), wherein a first commutation geometry (18) and a second commutation geometry (19) are arranged between the sleeve (12) and the housing (3), wherein the commutation geometries (18, 19) are connected to the working chambers (15) of the measuring motor (14) and the housing includes a first direction port (4), a second direction port (5), a pressure port (6), and a return port (7). The object is to have a good steering behavior. To this end one of the commutation geometries (18) is directly connected to the first direction port (4).

The invention relates to a hydraulic steering unit (1) including a housing (3), a spool, a sleeve (12) arranged between spool and housing (3), and a measuring motor (14) having a number of working chambers (15), wherein a first commutation geometry (18) and a second commutation geometry (19) are arranged between the sleeve (12) and the housing (3), wherein the commutation geometries (18, 19) are connected to the working chambers (15) of the measuring motor (14) and the housing includes a first direction port (4), a second direction port (5), a pressure port (6), and a return port (7). The object is to have a good steering behavior. To this end one of the commutation geometries (18) is directly connected to the first direction port (4).

A fluid controller (1), in particular as part of a hydraulic steering unit, is described, said controller (1) comprising a housing (2) having a supply port arrangement, a sleeve (4) arranged rotatably in a bore of the housing (2), a spool (3) arranged rotatably in the sleeve (4), and a measuring motor, wherein the measuring motor comprises a plurality of working chambers, each working chamber being connected to the bore, wherein the sleeve (4) comprises a commutation geometry (7) having a number of pairs of commutation grooves (12, 13) and controlling together with a housing geometry (5) of the housing (2) a flow of hydraulic fluid into and out of the working chambers and the spool (3) comprises a spool geometry controlling together with a valve geometry of the sleeve (4) a flow of hydraulic fluid between the supply port arrangement and the commutation geometry. Such a fluid controller should have a stable control behaviour. To this end at least one of the commutation grooves (12, 13) comprise a closed bottom and at least one of the commutation grooves (12, 13) comprise a throughgoing opening (10, 11) forming part of the valve geometry.

A fluid controller (1), in particular as part of a hydraulic steering unit, is described, said controller (1) comprising a housing (2) having a supply port arrangement, a sleeve (4) arranged rotatably in a bore of the housing (2), a spool (3) arranged rotatably in the sleeve (4), and a measuring motor, wherein the measuring motor comprises a plurality of working chambers, each working chamber being connected to the bore, wherein the sleeve (4) comprises a commutation geometry (7) having a number of pairs of commutation grooves (12, 13) and controlling together with a housing geometry (5) of the housing (2) a flow of hydraulic fluid into and out of the working chambers and the spool (3) comprises a spool geometry controlling together with a valve geometry of the sleeve (4) a flow of hydraulic fluid between the supply port arrangement and the commutation geometry. Such a fluid controller should have a stable control behaviour. To this end at least one of the commutation grooves (12, 13) comprise a closed bottom and at least one of the commutation grooves (12, 13) comprise a throughgoing opening (10, 11) forming part of the valve geometry.