Electro-hydraulic drive system for a work machine
First Claim
1. An electro-hydraulic drive system for a work machine which drives a structure body by controlling a flow rate of a hydraulic fluid by a control valve, comprising:
- a supply device which includes a hydraulic pump driven by a driving power source, and a first electric motor, and supplies the hydraulic fluid;
a drive device which includes a hydraulic motor rotated by the hydraulic fluid supplied from the supply device, and a second electric motor, and drives the structure body; and
a controller which decides an operating state of the first electric motor and an operating state of the second electric motor, based on a load of the supply device and a load of the drive device;
wherein the first electric motor has a first generator function of converting driving power transmitted from the driving power source into electric energy, and a drive unit function of assisting driving of the hydraulic pump by utilizing the electric energy,wherein the second electric motor has a second generator function of converting inertia energy into the electric energy during deceleration of the hydraulic motor and a drive unit function of assisting driving of the hydraulic motor by utilizing the electric energy; and
wherein the controller performs control to operate each of the first electric motor and the second electric motor as a generator or a drive unit based on a state of charge in a charging unit which stores electric power generated by the first and second generator functions, the load of the supply device, and the load of the drive device.
1 Assignment
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Accused Products
Abstract
An electro-hydraulic drive system for a work machine which drives an upper rotary body by controlling a flow rate of a hydraulic fluid by a control valve, includes an electro-hydraulic pump including a hydraulic pump driven by an engine, and a first electric motor, and an electro-hydraulic motor including a hydraulic motor rotated by the hydraulic oil supplied from the electro-hydraulic pump, and a second electric motor, and a controller which determines an operating state of the first electric motor and an operating state of the second electric motor based on a load of the electro-hydraulic pump and a load of the electro-hydraulic motor, and is able to perform an efficient operation by using a hydraulic pressure (fluid pressure) and electric power.
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Citations
7 Claims
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1. An electro-hydraulic drive system for a work machine which drives a structure body by controlling a flow rate of a hydraulic fluid by a control valve, comprising:
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a supply device which includes a hydraulic pump driven by a driving power source, and a first electric motor, and supplies the hydraulic fluid; a drive device which includes a hydraulic motor rotated by the hydraulic fluid supplied from the supply device, and a second electric motor, and drives the structure body; and a controller which decides an operating state of the first electric motor and an operating state of the second electric motor, based on a load of the supply device and a load of the drive device; wherein the first electric motor has a first generator function of converting driving power transmitted from the driving power source into electric energy, and a drive unit function of assisting driving of the hydraulic pump by utilizing the electric energy, wherein the second electric motor has a second generator function of converting inertia energy into the electric energy during deceleration of the hydraulic motor and a drive unit function of assisting driving of the hydraulic motor by utilizing the electric energy; and wherein the controller performs control to operate each of the first electric motor and the second electric motor as a generator or a drive unit based on a state of charge in a charging unit which stores electric power generated by the first and second generator functions, the load of the supply device, and the load of the drive device. - View Dependent Claims (3, 4, 6, 7)
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2. An electro-hydraulic drive system for a work machine which drives a structure body by controlling a flow rate of a hydraulic fluid by a control valve, comprising:
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a supply device which includes a hydraulic pump driven by the driving power source, and a first electric motor, and supplies the hydraulic fluid; a drive device which includes a hydraulic motor rotated by the hydraulic fluid supplied from the supply device, and a second electric motor, and drives the structure body; and a controller which decides an operating state of the first electric motor and an operating state of the second electric motor, based on a load of the supply device and a load of the drive device; wherein the drive device is configured such that the hydraulic motor and the second electric motor are integral with each other; wherein the second electric motor includes a rotor connected to a rotary shaft of the hydraulic motor and a stator disposed on an outer periphery of the rotor; and wherein the rotor is disposed to surround an outer periphery of a casing of the hydraulic motor such that the rotor is spaced apart a predetermined gap from the outer periphery of the casing; and wherein a bearing for supporting the rotor on the casing and a seal member for sealing the gap between the rotor and the casing are disposed between the rotor and the casing. - View Dependent Claims (5)
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Specification