Hybrid Construction Machine Swing Mode Switching
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Solution Overview
Problem
Hybrid construction machines using both hydraulic and electric motors for swing structures face issues such as hunting, operational strangeness, overheating, increased size or cost of electric motors, and insufficient torque during electric motor failures or low energy states, leading to safety concerns and operational inefficiencies.
Innovation Solution
A hybrid construction machine with a control system that switches between hydraulic/electric hybrid swing mode and hydraulic-alone swing mode, allowing normal braking torque to be maintained using the hydraulic motor when the electric motor fails or energy is insufficient, ensuring continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an electric motor is used to drive the swing structure, then energy efficiency is improved through regeneration of kinetic energy, but reliability deteriorates due to hunting, overheating, and failure risks
Solution Approach 1:
The system dynamically changes the swing mode parameter between hydraulic/electric hybrid mode and hydraulic-alone mode based on the electric motor's operational state. When parameters such as temperature, vibration, or current exceed thresholds indicating potential failure, the system switches to hydraulic-alone mode to maintain reliability while preserving energy efficiency benefits during normal operation.
2Power
If an electric motor with high output torque is used, then power is improved to match hydraulic motor performance, but device complexity and cost increase due to larger motor size
Solution Approach 1:
The system dynamically adjusts the displacement of the hydraulic pump based on operational requirements. During high-power需求的 swing operations, the pump displacement is increased to provide sufficient torque. During normal or low-power operations, the pump displacement is reduced, allowing the use of a smaller electric motor while maintaining overall system power capability.
3Loss of energy
If the electric motor is the primary drive, then energy efficiency is improved, but ease of operation deteriorates due to different characteristics from conventional hydraulic motors
Solution Approach 1:
The system maintains universality by supporting both hydraulic/electric hybrid swing mode and hydraulic-alone swing mode. This allows the system to operate in electric motor mode for energy efficiency during normal conditions, while seamlessly switching to conventional hydraulic mode when operators need familiar characteristics or during high-power需求的 operations, making the system adaptable to different operational preferences.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables satisfactory operations even when the electric motor is unable to output torque, providing normal swing torque and immediate startup capabilities by switching to hydraulic-alone mode, enhancing safety and energy efficiency.
Implementation Method 1
In deceleration (braking), the electric motor regenerates the kinetic energy of the swing structure into electric energy
Implementation Method 2
drives hydraulic actuators (hydraulic motor, hydraulic cylinder, etc.) using hydraulic pressure generated by a hydraulic pump
Data Source
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AI summary
Provided is a hybrid construction machine (construction machine using an electric motor for driving a swing structure) capable of performing satisfactory operations even when trouble disabling the electric motor from outputting torque has occurred for some reason. The hybrid construction machine is equipped with both a hydraulic motor 27 and an electric motor 25 for the driving of the swing structure and a controller 80 for switching between a hydraulic/electric hybrid swing mode (using both the hydraulic motor and the electric motor) and a hydraulic-alone swing mode (using only the hydraulic motor). The switching is executed while achieving satisfactory operability and performance in each mode. Normally, an energy saving operation is performed in the hydraulic/electric hybrid swing mode. When the electric amount of an electricity storage device has gone out of a prescribed range or an abnormality has occurred in an electric system (e.g., failure of an inverter), the swing mode is switched to the hydraulic-alone swing mode so that driving with normal braking torque is possible by the hydraulic motor alone.