Hybrid Swing Drive Torque Allocation for Construction Machines
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Solution Overview
Problem
Conventional construction machines using both hydraulic and electric motors for swing bodies face issues with torque matching the manipulation of the swing control lever, leading to operational discomfort and inefficiencies due to constant torque allocation by the electric motor, and potential failures in energy regeneration.
Innovation Solution
A hybrid-type construction machine employing a composite swing mode using both swing hydraulic and electric motors, and an independent hydraulic motor mode, with a configuration that adjusts torque allocation based on the swing control lever's position, ensuring energy-saving operations and maintaining basic performance even if the electric motor fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an electric motor is used to drive the swing body, then energy regeneration efficiency is improved, but operational comfort and control performance deteriorate due to hunting and time delay
Solution Approach 1:
The invention divides the swing body driving system into two separate motors: a swing electric motor for energy-efficient driving and regeneration, and a swing hydraulic motor for providing supplemental torque during high-load operations. This segmentation allows each motor to operate in its optimal performance range, maintaining operational comfort while achieving energy savings
Solution Approach 2:
The invention combines the swing electric motor and swing hydraulic motor into a hybrid drive system where both motors work together to drive the swing body. The electric motor handles normal operations with energy regeneration, while the hydraulic motor provides additional torque during ditching and high-load conditions, merging the advantages of both motor types
2Loss of energy
If an electric motor is used to drive the swing body, then energy utilization efficiency is improved, but device complexity and cost increase due to motor oversizing
Solution Approach 1:
The invention segments the torque delivery function between two motors of different sizes and characteristics. The swing electric motor is sized for efficient energy regeneration during normal operations, while the swing hydraulic motor provides supplemental power during peak demand, eliminating the need for one oversized motor
Solution Approach 2:
The invention changes the system configuration from a single motor to a dual-motor system with different operational parameters. The electric motor operates at optimal efficiency points for regeneration, while the hydraulic motor activates based on torque demand thresholds, optimizing overall system performance without oversizing
3Device complexity
If torque allocation between hydraulic motor and electric motor is constant, then system simplicity is maintained, but torque matching with swing control lever manipulation deteriorates
Solution Approach 1:
The invention implements dynamic torque allocation where the controller continuously adjusts the torque distribution between the swing electric motor and swing hydraulic motor based on the swing control lever position and operational conditions. This dynamic adjustment ensures optimal torque matching across the full range of operations while maintaining reasonable system complexity
4Ease of operation
If electric motor continuously outputs torque during non-rotation, then operational capability is maintained, but motor and inverter overheating occurs
Solution Approach 1:
The invention combines the swing electric motor with a swing hydraulic motor that can provide continuous torque output during non-rotation conditions. The hydraulic motor handles operations like ditching where continuous torque is needed, while the electric motor handles rotational movements, dividing the thermal load and preventing overheating
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
This configuration provides high operability and energy efficiency by ensuring the desired torque is matched to the swing control lever's manipulation, reducing operator discomfort and maintaining machine performance despite potential electric motor issues.
Implementation Method 1
a swing electric motor connected to the swing hydraulic motor and driven by electric power that an electricity storage device supplies
Implementation Method 2
a swing hydraulic motor driven by an oil pressure that a hydraulic pump generates when driven by an engine
Implementation Method 3
since the swing body having the heavy inertial load causes the electric motor to function as an electric power generator, output energy from the electric motor can be regenerated as electrical energy
Data Source
AI summary
Disclosed is a hybrid-type construction machine equipped with a swing hydraulic motor 27 and a swing electric motor 25 in combination to save energy, the construction machine ensuring high operability of a swing body 20 and providing high energy efficiency. In accordance with the amount of manipulation of a swing control lever 72, the construction machine changes a rate of a torque of the swing electric motor 25 with respect to that of the swing hydraulic motor 27. The construction machine also controls a relief pressure and the torque of the swing electric motor 25 in accordance with the amount of manipulation of a swing control lever 72, a pressure of the swing hydraulic motor 27, and a rotating speed of the swing electric motor 25.