Drive Assembly Clutch Synchronization for Imperceptible Shifting
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Solution Overview
Problem
In towing vehicles with power-shift transmissions, the overlapping control of clutches leads to torque direction reversals during shifting, making the shifting process less comfortable and perceptible.
Innovation Solution
A method for operating a drive assembly that involves identifying a target torque progression, recognizing a slip point, adjusting the relative rotational speed of clutches to match, and synchronizing them to ensure seamless torque transfer, using a main drive element to control the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If overlapping control of two clutches is used for gear shifting, then gear shifting capability is improved, but torque control difficulty increases and shifting comfort deteriorates
Solution Approach 1:
The control unit continuously monitors the actual torque progression during shifting and compares it with the target torque progression. Based on this feedback, the control unit dynamically adjusts the clutch control parameters to ensure the actual torque follows the desired target curve, thereby resolving the torque control difficulty while maintaining gear shifting capability
Solution Approach 2:
The system pre-calculates and stores target torque progressions for different operating conditions before shifting occurs. By having the target torque curve ready in advance, the control system can immediately guide the clutch transition process, improving both torque control precision and shifting comfort
2Adaptability or versatility
If overlapping control of two clutches is used for gear shifting, then gear shifting capability is improved, but shifting perceptibility increases (comfort deteriorates)
Solution Approach 1:
The control unit uses feedback from actual torque measurements to continuously adjust clutch control, ensuring the torque progression remains smooth and follows the pre-calculated target curve. This feedback mechanism suppresses torque fluctuations and reversals that would otherwise be perceptible to the operator, making shifts imperceptible while maintaining shifting capability
Solution Approach 2:
The system dynamically changes clutch control parameters (such as torque capacity and engagement timing) during the shifting process to maintain a smooth torque progression. By adjusting these parameters in real-time based on the target torque curve, the system eliminates perceptible torque reversals while completing the gear shift
3Productivity
If torque direction reversals occur during clutch switching, then gear shifting is completed, but shifting comfort and smoothness deteriorate
Solution Approach 1:
The system pre-calculates target torque progressions that specifically prevent torque direction reversals during clutch transition. By having the optimal torque curve determined in advance, the clutch control can follow this smooth path, completing the gear shift without causing perceptible torque fluctuations or reversals that would reduce shifting comfort
Solution Approach 2:
The control unit continuously compares actual torque with the target torque progression and adjusts clutch control to eliminate any tendency toward torque direction reversals. This real-time feedback ensures the torque progression remains monotonic and smooth, completing the shift while maintaining high comfort levels
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 a structurally simpler, more compact, and imperceptible shifting procedure by accurately controlling torque transfer between clutches, enhancing shifting comfort and efficiency.
Implementation Method 1
The first and second clutch can be friction clutches
Data Source
AI summary
The disclosure relates to a method for operating a drive assembly or a work machine. The drive assembly comprises a main drive element, a first and second clutches, and a traction drive. The method comprises the following steps: identifying a target torque progression of the drive assembly, and identifying a slip point at the first clutch, and setting and/or adjusting the direction of the relative rotational speed of the first and second clutch. The rotational speed of the main drive element is set and/or adjusted until the direction of the relative rotational speed of the first and second clutches is the same, and transmitting the torque from the first clutch to the second clutch. The torque of the drive assembly follows the target torque progression, and synchronizing the second clutch. The disclosure further relates to a drive assembly and to a work machine.