Abstract: A hydraulic system includes a first pump, a first actuator fluidly connected to the first pump via a first closed-loop circuit, a second pump, and a second actuator fluidly connected to the second pump via a second closed-loop circuit. The system also includes a third pump, a third actuator fluidly connected to the third pump via a third closed-loop circuit, a fourth pump, and a fourth actuator fluidly connected to the fourth pump via a fourth closed-loop circuit. The system further includes a first combining valve configured to combine fluid from the first and second circuits, a second combining valve configured to combine fluid from the second and third circuits, and a third combining valve configured to combine fluid from the third and fourth circuits. The system also includes a fourth combining valve configured to combine fluid from the first and fourth circuits.

Abstract: A method of controlling a hydraulic system includes providing fluid to a first actuator with a first pump via a first closed-loop circuit of a machine, and providing fluid to a second actuator with a second pump via a second closed-loop circuit of the machine. The method also includes providing fluid to a third actuator with a third pump via a third closed-loop circuit of the machine, and providing fluid to a fourth actuator with a fourth pump via a fourth closed-loop circuit of the machine. The method further includes forming a combined flow of fluid including fluid from the first circuit and fluid from at least one of the second, third, and fourth circuits, and directing the combined flow to the first actuator while providing fluid to the actuator of the at least one of the second, third, and fourth circuits.

Abstract: A hydraulic system includes a variable displacement first pump, a first linear actuator fluidly connected to the first pump via a first closed-loop circuit, a variable displacement second pump, and second and third linear actuators fluidly connected to the second pump in parallel via a second closed-loop circuit. The system also includes a variable displacement third pump, a fourth linear actuator fluidly connected to the third pump via a third closed-loop circuit, a variable displacement fourth pump, and a first rotary actuator fluidly connected to the fourth pump via a fourth closed-loop circuit. The system further includes a second rotary actuator fluidly connected to the second pump in parallel with the second and third linear actuators. The system also includes a third rotary actuator fluidly connected to the third pump in parallel with the fourth linear actuator.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump, and a hydraulic actuator having a first chamber and a second chamber. The hydraulic system may also have a first pump passage fluidly communicating the pump with the first chamber, a second pump passage connected to the pump, and a regeneration valve. The regeneration valve may be movable from a first position at which the second pump passage is connected to the second chamber and the second chamber is isolated from the first chamber, to a second position at which the second pump passage is blocked and the second chamber is connected to the first chamber.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump with variable-displacement, a first linear actuator, and a second linear actuator coupled to the first linear actuator to operate in tandem. The first and second linear actuators may be connected to the pump in closed-loop manner, and each of the first and second linear actuators may have a first chamber and a second chamber separated by a piston. The hydraulic system may also have an accumulator in fluid communication with the second chamber of only the second linear actuator.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a primary pump, a hydraulic actuator, and first and second passages fluidly connecting the primary pump to the hydraulic actuator in a closed-loop manner. The hydraulic system may also have a charge circuit, a makeup valve movable to selectively allow charge fluid from the charge circuit to enter the first or second passages, and at least one restricted pilot passage configured to direct pilot fluid to the makeup valve to move the makeup valve and allow the charge fluid into the first and second passages.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump, a tank, a displacement actuator having first and second chambers, a regeneration valve, and a load-holding valve. The hydraulic system may also have a displacement control valve including a valve element, and a stationary cage portion at least partially forming a high-pressure passage fluidly connecting the pump and valve element, a low-pressure passage fluidly connecting the valve element and tank, a first displacement actuator passage fluidly connecting the valve element and first chamber, a second displacement actuator passage fluidly connecting the valve element and second chamber, a load-holding control passage fluidly connecting the valve element and load-holding valve, and a regeneration control passage fluidly connecting the valve element and regeneration valve.

Abstract: A hydraulic system is disclosed. The hydraulic system may have a pump, a hydraulic actuator, and first and second passages fluidly connecting the pump to the hydraulic actuator in a closed-loop. The hydraulic system may also have a control valve, and a load-holding valve configured to selectively lock movement of the hydraulic actuator. The load-holding valve may include a valve block at least partially defining a pump passage, an actuator passage, a control passage, a restricted passage connecting the actuator passage and the control passage, and a bypass passage connecting the actuator passage and the control passage. The load-holding valve may also include a valve element movable between a first position at which flow between the pump and the hydraulic actuator is blocked, and a second position at which fluid is allowed to flow between the pump and the hydraulic actuator, the valve element being spring-biased toward the first position.

Abstract: An axial piston device for use with a hydraulic system is disclosed. The axial piston device may have a body defining at least one bore and having a central axis, a pump piston disposed within the at least one bore to at least partially define a pumping chamber, and a tiltable plate biased into engagement with the pump piston. The axial piston device may also have an actuator configured to selective tilt the plate relative to the central axis of the body to thereby vary a displacement of the pump piston within the at least one bore. The actuator may have a control piston operatively connected to move the tiltable plate, a rotary motor, and a valve driven by the rotary motor to control fluid communication between the control piston and a source of pressurized fluid to move the control piston.

Abstract: An axial piston device for use with a hydraulic system is disclosed. The axial piston device may have a body defining at least one bore and having a central axis, a pump piston disposed within the at least one bore to at least partially define a pumping chamber, and a tiltable plate biased into engagement with the pump piston. The axial piston device may also have an actuator configured to selective tilt the plate relative to the central axis of the body to thereby vary a displacement of the pump piston within the at least one bore. The actuator may have a control piston operatively connected to move the tiltable plate, a rotary motor, and a valve driven by the rotary motor to control fluid communication between the control piston and a source of pressurized fluid to move the control piston.

Abstract: A hydraulic system (20) for controlling the seed/fertilizer supply system (10) and the down pressure on a plurality of individual row units (12). A secondary supply arrangement (60) interconnects a first control circuit (26) of supply system (10) with a second control circuit (28), when the row units (12) are in a float mode, to provide pressurized fluid for the down force on the row units (12) during operation.

Abstract: A track belt tensioning management system is provided for actively adjusting the tension on a track belt in response to the difference in linear output speed between a drive wheel and the track belt. This is accomplished by sensing the speeds of the drive wheel and the track belt and delivering the sensed signals to a controller which processes the signals and determines the difference in their respective linear output speeds. If the difference varies from a predetermined value, the controller directs appropriate signals to a hydraulic valve arrangement which controllably directs pressurized fluid to and from a hydraulic actuator arrangement to adjust the tension between the drive wheel and the track belt. The subject arrangement maintains sufficient frictional force between the drive wheel and the belt to control the slip therebetween as required while at the same time limiting the forces in order to reduce premature failures and/or wear on the track belt and other associated components.

Abstract: A rotary control valve includes a directional control valve having a rotatable valve element for controlling the direction of fluid flow from an input passage to a pair of control ports and from the control ports to a drain passage. A pressure regulating valve is connected to a source of pilot pressure and has a valve spool for controlling the regulated pressure level of pilot fluid in the input passage. A cam is connected to the valve element for unitary rotation therewith. A spring and a plunger are disposed between the valve spool and the cam so that the valve spool is mechanically moved in a rectilinear direction by the cam in either direction from a neutral position to increase the level of the regulated pressure in the input passage proportional to the degree of rotation of the rotatable valve element.