Hydraulic System Recovering Swing Kinetic and Boom Potential Energy

摘要

Swing kinetic and boom potential energy may be recovered in a machine having a movable work tool, a swing motor for rotating the work tool, a hydraulic cylinder for raising and lowering the work tool, a pump selectively connected to the swing motor and the hydraulic cylinder, and a power source outputting power to drive the pump. The machine may further include a first accumulator, a swing charge valve having a charge set pressure, and a boom charge valve. The swing charge valve selectively fluidly connect the swing motor to the first accumulator, and open to fluidly connect the swing motor to the first accumulator when a swing motor fluid pressure is greater than a charge set pressure of the swing charge valve. The boom charge valve may selectively fluidly connect a head-end chamber of the hydraulic cylinder to the first accumulator when the work tool is lowered.

主权项

1. A machine, comprising:
a work tool movable through a range of motion; a swing motor configured to swing the work tool about a vertical axis; a hydraulic cylinder having a head-end chamber and being configured to raise and lower the work tool; a pump selectively fluidly connected to the swing motor and to the hydraulic cylinder to provide pressurized fluid to cause the swing motor to swing the work tool and to cause the hydraulic cylinder to raise and lower the work tool; a power source operatively connected to the pump to output power to drive the pump; a first accumulator; a swing charge valve having a normally closed position, an open position, and a charge set pressure, the swing charge valve being positioned to selectively fluidly connect the swing motor to the first accumulator, wherein the swing charge valve moves from the normally closed position to the open position and fluidly connects the swing motor to the first accumulator when a swing motor fluid pressure communicated to the swing charge valve from the swing motor is greater than the charge set pressure; and a boom charge valve having a normally closed position and an open position, the boom charge valve being positioned to selectively fluidly connect the head-end chamber of the hydraulic cylinder to the first accumulator.