Parker-hannifin Corporation

Patrick Stegemann

Hao Zhang

Raymond E Collett

James Howland

Jarmo Antero Harsia

Jeff Cullman

Nick White

A hybrid swing drive system () of a hydraulic construction machine includes a variable displacement hydraulic swing pump () operable by a prime mover (); a hydraulic swing motor () for performing a swing function of the machine; an accumulator (); a controller (); a swing control valve assembly () disposed in a first hydraulic path extending from the swing pump to the swing motor, the swing control valve assembly having a first position fluidly connecting the swing pump to a first side of the swing motor and a second position fluidly connecting the swing pump to a second side of the swing motor; and an accumulator control valve () having an open position fluidly connecting the accumulator to the first hydraulic path at an accumulator control valve connection point and a closed position fluidly isolating the accumulator from the first hydraulic path.

Hydraulic hybrid swing drive system for excavators

A load sense open center hydraulic system provides efficiency and operator feedback and includes one or more constant flow-open center valves (); respective one or more parallel power cores () operatively coupled to the one or more constant flow-open center valves; a variable capacity pump () directly fluidly connected to the one or more parallel power cores; and a pressure compensated flow control fluidly connected between the variable capacity pump and the one or more constant flow-open center valves. The one or more constant flow-open center valves are not fluidly coupled to a fixed capacity pump.

Variable load sense open center hybrid system

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Arlington Heights, IL, United States of America

Patrick Stegemann