Hydraulic Flow Control for Efficient Construction Machines
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Summary
Problems
Existing energy recovery devices for construction machines, such as hydraulic excavators, face issues with controlling the flow rate of return hydraulic fluid, leading to potential drops in swing braking pressure and operability, due to inadequate control methods and responsiveness.
Innovation solutions
A construction machine equipped with a regeneration device, pressure detection, and a control unit that sets a target flow rate for the regenerative hydraulic motor based on detected pressure, ensuring the flow rate matches the relief flow rate of overload relief valves, and controls the generator/motor to maintain hydraulic pressure, thereby maintaining operability equivalent to conventional systems.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If the flow rate through the regenerative hydraulic motor is increased to improve energy regeneration efficiency, then the recovery flow rate increases, but the swing braking pressure drops and operability deteriorates
Why choose this principle:
The patent applies dynamics by making the regenerative hydraulic motor's flow rate adjustable and responsive to real-time pressure conditions. The control unit dynamically modifies the target flow rate based on detected pressure values, allowing the system to adapt between high-flow regeneration mode and pressure-maintenance mode, thus resolving the contradiction between regeneration efficiency and braking pressure stability
Principle concept:
If the flow rate through the regenerative hydraulic motor is increased to improve energy regeneration efficiency, then the recovery flow rate increases, but the swing braking pressure drops and operability deteriorates
Why choose this principle:
The patent implements feedback control by using a pressure detection device to continuously monitor hydraulic pressure and feeding this information back to the control unit. The control unit compares detected pressure against reference values and adjusts the regenerative hydraulic motor's flow rate accordingly, ensuring that regeneration efficiency is maximized only when pressure conditions permit, thereby maintaining swing braking pressure and operability
Application Domain
Data Source
AI summary:
A construction machine equipped with a regeneration device, pressure detection, and a control unit that sets a target flow rate for the regenerative hydraulic motor based on detected pressure, ensuring the flow rate matches the relief flow rate of overload relief valves, and controls the generator/motor to maintain hydraulic pressure, thereby maintaining operability equivalent to conventional systems.
Abstract
A controller sets a target flow rate of a regenerative hydraulic motor at zero or a low flow rate within an extent in which hydraulic pressure in a regeneration hydraulic line does not become negative pressure when a detected pressure PS detected by a pressure sensor is lower than a first set value previously set by overload relief valves, sets the target flow rate of the regenerative hydraulic motor at a value corresponding to the detected pressure when the detected pressure is higher than or equal to the first set value, and controls the revolution speed of a generator/motor in such a manner that a flow rate through the regenerative hydraulic motor equals the target flow rate. With such features, excellent operability equivalent to that in the conventional technology can be secured.