Danfoss A/s

Roger D Lowman

Chad Anthony Larish

Stephen Smith

Sam Newbauer

A load sense hydraulic system includes pressure sensors that provide feedback to an electronic controller to monitor a pressure margin between a pump supply pressure and an actuator meter-in load pressure. Pre-collapse and collapse of the pressure margin (the collapse indicating a deadhead or stall condition of the actuator), can be tracked by the electronic controller to establish a normal operating pressure margin. The established normal operating pressure margin can be assessed by the controller against a current, actual pressure margin based on feedback from the pressure sensors. A pre-determined threshold variation by the actual pressure margin from the normal operating pressure margin provides an indication of deadhead or stall condition to the controller. The controller may then responsively make modifications to the load sense hydraulic system to remedy the deadhead/stall condition.

Actuator deadhead/stall detection in a load sense hydraulic system

A hydraulic system can include a hydraulic actuator including a piston rod slidably disposed within a housing having a base-side port and a rod-side port, a hydraulic pump, a hydraulic reservoir, an accumulator, a first control valve operable to selectively control flow from the pump to the base-side port and from the base-side port to the reservoir, a second control valve operable to selectively control flow from the pump to the rod-side port and from the rod-side port to the reservoir, a third control valve operable to selectively allow flow between the base-side port and the accumulator, and a controller for operating the hydraulic system and including a ride control mode in which damping is provided to the hydraulic actuator by operation of the first, second, and third control valves.

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Simpsonville, SC, United States of America

Roger D Lowman