Hydraulic hybrid swing drive system for excavators
First Claim
1. A hybrid swing drive system of a hydraulic machine comprising:
- an over center variable displacement hydraulic swing pump/motor operable by a prime mover and configured to be stroked over center to act as a motor;
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/motor to the swing motor, the swing control valve assembly having a first position fluidly connecting the swing pump/motor to a first side of the swing motor and a second position fluidly connecting the swing pump/motor 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;
wherein, in an operating mode, the controller is configured to direct flow from the hydraulic swing motor to the hydraulic swing pump/motor;
wherein, in a second operating mode, the controller is configured to direct flow from the hydraulic swing motor to the accumulator;
wherein, in a third operating mode, the controller is configured to direct flow from the accumulator to the hydraulic swing motor;
wherein, in a fourth operating mode, the controller is configured to direct flow from the accumulator to the hydraulic swing pump/motor in a first direction through the hydraulic swing pump/motor and the swing pump/motor is stroked over center to act as a motor; and
wherein, in a fifth operating mode, the controller is configured to direct flow from the hydraulic swing pump/motor to the accumulator in a second direction through the hydraulic swing pump/motor that is opposite that of the first direction, and the swing pump/motor is stroked to act as a pump to charge the accumulator.
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Accused Products
Abstract
A hybrid swing drive system (1) of a hydraulic construction machine includes a variable displacement hydraulic swing pump (3) operable by a prime mover (2); a hydraulic swing motor (16) for performing a swing function of the machine; an accumulator (10); a controller (244); a swing control valve assembly (15) 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 (12) 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.
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Citations
23 Claims
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1. A hybrid swing drive system of a hydraulic machine comprising:
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an over center variable displacement hydraulic swing pump/motor operable by a prime mover and configured to be stroked over center to act as a motor; 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/motor to the swing motor, the swing control valve assembly having a first position fluidly connecting the swing pump/motor to a first side of the swing motor and a second position fluidly connecting the swing pump/motor 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; wherein, in an operating mode, the controller is configured to direct flow from the hydraulic swing motor to the hydraulic swing pump/motor; wherein, in a second operating mode, the controller is configured to direct flow from the hydraulic swing motor to the accumulator; wherein, in a third operating mode, the controller is configured to direct flow from the accumulator to the hydraulic swing motor; wherein, in a fourth operating mode, the controller is configured to direct flow from the accumulator to the hydraulic swing pump/motor in a first direction through the hydraulic swing pump/motor and the swing pump/motor is stroked over center to act as a motor; and wherein, in a fifth operating mode, the controller is configured to direct flow from the hydraulic swing pump/motor to the accumulator in a second direction through the hydraulic swing pump/motor that is opposite that of the first direction, and the swing pump/motor is stroked to act as a pump to charge the accumulator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A hybrid swing drive system of a hydraulic machine comprising:
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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; wherein the controller is configured to close the accumulator control valve, meter flow through a dump valve, and engage the swing pump for use as a motor.
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Specification