Caterpillar Inc.

Michael L Knussman

Patrick Opdenbosch

Jeremy Todd Peterson

Joshua Dierking

Jeffrey Lee Kuehn

Brad Allen Edler

Arlyn P Wilcox

Jiao Zhang

Dayao Chen

Michael Todd Verkuilen

Hans P Dietz

William J Spivey

David R Meinhold

David J Lomax

Brad L Holsapple

William C Evans

Stephen T Tady

Cory Lynn Fisher

William Edward Frank

Glen P Running

A hydraulic system is disclosed. The hydraulic system may include a fluid source and an actuator having a first passage and a second passage. The hydraulic system may further include a pump having a first port connected to the first passage, a second port connected to the second passage, and a third port connected to the fluid source. The first and second passages may be connected to each other via the first and second ports, and the first passage and the low-pressure fluid source may be connected to each other via the first and third ports. They hydraulic system may further include a charge circuit fluidly connected to the first and second passages, and at least one damping control valve configured to selectively allow fluid from the pump to pass into the charge circuit to dampen pressure oscillations between the actuator and the pump.

Hydraulic system having regeneration and hybrid start

A hydraulic control system for a machine is provided. The hydraulic control system includes a fluid reservoir, a pump motor and an accumulator. The pump motor is configured to provide pressurized fluid and to receive fluid to provide a power output. The hydraulic control system further includes a hydraulic actuator having a first and a second chamber, a first valve, a regenerative valve, and a controller. The controller is in communication with the first valve and the regenerative valve to selectively actuate the regenerative valve to allow flow of a first portion of the fluid from the first chamber to the second chamber. The controller is further configured to selectively actuate the first valve to allow flow of a second portion of the fluid from the first chamber through the pump motor to provide the power output to a shaft of a power source.

System and method for hydraulic energy recovery

A method for storing and reusing hydraulic energy in a machine is disclosed. The method includes transferring the hydraulic energy from an actuator to an upstream side of a motor pump via a first valve, during a normal mode. The method includes directing excess hydraulic energy from a downstream side of the motor pump to an accumulator by opening an accumulator valve and closing a bypass valve, during an energy saving mode. The method includes retrieving stored hydraulic energy from the accumulator to the upstream side of the motor pump by opening the accumulator valve, during an energy discharging mode.

Method and system for storing and reusing hydraulic energy

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.

Closed-loop hydraulic system having energy recovery

A hydraulic system is disclosed that has first and second passages connecting a pump to an actuator in closed-loop manner, and first and second load-holding valves within the first and second passages. The hydraulic system may also have a regeneration valve connected to the first and second passages between the actuator and the first and second load-holding valves to selectively connect the first and second passages. The hydraulic system may further have a controller configured to cause a control valve to simultaneous move the first and second load-holding valves toward flow-blocking positions when pump displacement is about zero. The controller may also be configured to selectively cause the regeneration valve to connect the first and second passages when pump displacement is non-zero, and to cause only one of the first and second load-holding valves to move to its flow-blocking position when the regeneration valve connects the first and second passages.

Closed-loop hydraulic system having regeneration configuration

A machine is disclosed. The machine can include a frame and ground engaging propulsion elements coupled with the frame. A hydraulically actuated implement system can be coupled with the frame, and can include a linkage configured to couple with an implement, a hydraulic actuator coupled with the linkage and the frame, and a ride control and downforce control circuit configured to implement a ride control mode and a downforce control mode. The ride control mode can be configured to maintain a pressure of hydraulic fluid in the hydraulic actuator at a ride control pressure, and the downforce control mode can be configured to maintain the pressure of hydraulic fluid in the hydraulic actuator at a downforce control pressure to oppose the weight of the linkage and the implement such that the implement engages a substrate with a predetermined down force pressure which is proportionate to the downforce control pressure.

Machine having hydraulically actuated implement system with combined ride control and downforce control system

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.

Meterless hydraulic system having restricted primary makeup

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.

Hydraulic system

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. The displacement control valve may also include a movable cage portion that is movable to selectively restrict fluid flow through only the first and second displacement actuator passages.

Meterless hydraulic system having displacement control valve

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.

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.

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.

Meterless hydraulic system having load-holding bypass

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.

Axial piston device having rotary displacement control

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

Hydraulic system providing down force on a work implement

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.

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East Peoria, IL, United States of America

Michael L Knussman