Rail Drive System Speed Synchronization for Clutch Protection
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Solution Overview
Problem
In rail vehicles with electric drive systems and manual transmissions, speed differences between wheelsets due to production tolerances and wear cause mechanical stresses and issues during gear shifting, particularly with positive-locking clutches, leading to potential mechanical damage and synchronization challenges.
Innovation Solution
A drive system with a common AC converter feeding multiple electric drive machines, each with a manual gearbox, incorporates a partial load shifting element to synchronize input and output speeds at positive-locking clutches, using a service brake as a partial load shifting element to compensate for speed differences and facilitate smooth gear shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common AC converter feeds multiple electric drive machines to reduce cost, then device complexity is reduced, but speed differences between wheelsets cause mechanical stresses and shifting problems
Solution Approach 1:
The control device performs preliminary speed synchronization before the shifting operation. The AC converter adjusts the rotational speeds of the drive trains so that the input speed and output speed at the positive-locking clutch are synchronized within a predetermined speed difference range before the clutch is engaged, preventing mechanical damage during shifting.
Solution Approach 2:
The control device continuously monitors the rotational speeds of the drive trains and dynamically adjusts the AC converter output to maintain speed synchronization. This feedback mechanism ensures that speed differences remain within acceptable limits during both normal operation and shifting transitions.
2Reliability
If positive-locking clutches are used in manual transmissions for reliable gear engagement, then shifting reliability is improved, but speed synchronization issues cause mechanical damage to clutch teeth and shifting claws
Solution Approach 1:
The system performs preliminary speed synchronization before engaging the positive-locking clutch. The control device ensures that the input speed and output speed are matched within a predetermined range before the clutch teeth engage, preventing the mechanical damage that would otherwise occur due to speed differences.
Solution Approach 2:
The control device applies preliminary anti-action by actively compensating for speed differences before they can cause damage. The AC converter adjusts motor speeds to prevent the harmful speed mismatch from occurring in the first place, rather than merely mitigating its effects after damage begins.
3Ease of manufacture
If wheel diameter differences due to production tolerances and wear are accepted, then manufacturing cost is reduced, but speed differences arise between drive trains
Solution Approach 1:
The control device dynamically changes the operational parameters of the electric drive machines to compensate for wheel diameter differences. By adjusting motor speeds and torques, the system maintains synchronized output speeds from different drive trains despite variations in wheel dimensions caused by manufacturing tolerances or wear.
Solution Approach 2:
The system transitions from a static speed specification approach to a dynamic speed control approach. The AC converter continuously adjusts the speed commands to individual drive machines based on real-time feedback, allowing the system to adapt to changing wheel conditions while maintaining overall synchronization.
Data Source
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AI summary
The invention relates to a drive system of a rail vehicle comprising several drive trains, each having an electric drive engine and a transmission with at least one positively engaging shifting clutch for producing several transmission ratios. The electric drive machines are fed via a common alternating current converter. At least one drive train of the drive system comprises a partial load shift element for synchronizing an input speed of rotation with an output speed of rotation on the positively engaging shifting clutch. The invention also relates to a method for controlling a corresponding shifting operation.