Slew Drive Seizure Detection and Reverse Control for Paving Tracks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Paving machines equipped with slew drives often experience component failures due to over or under-driving, axial overload, and impact loading, leading to issues like bearing failure and lock-up, which affect the reliability and operational life of the machinery.
Innovation Solution
A paving machine system that includes a processor configured to engage and control slew drives using angle sensors and pressure transducers to detect seizures and adjust power supply, reversing the slew drive direction when a seizure is detected to prevent lock-up and reduce component failure, and periodically engaging the slew drive to maintain hydraulic pressure within safe limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a slew drive is used to provide rotational movement with greater range of motion, then the range of motion is improved, but the reliability deteriorates due to over/under driving, axial overload, and impact loading causing bearing failure and lock-up
Solution Approach 1:
The control system performs preliminary detection of seizure conditions by monitoring hydraulic pressure and angular position before actual lock-up occurs. When a seizure condition is detected, the system preemptively reverses the slew drive rotation to prevent complete lock-up and component failure, thereby maintaining reliability while preserving the advantageous range of motion of the slew drive configuration
Solution Approach 2:
The system implements continuous feedback monitoring through angle sensors and pressure transducers that track the rotational position and hydraulic pressure of the slew drive. This feedback loop enables real-time detection of abnormal conditions such as axial overload and impact loading, allowing the control system to adjust operation and prevent component failure while maintaining the full range of motion capability
2Measurement precision
If the slew drive operates continuously to maintain position, then the positioning accuracy is improved, but the reliability deteriorates due to prolonged exposure to axial overload and impact loading
Solution Approach 1:
Instead of continuous operation, the system uses periodic engagement of the slew drive combined with monitoring cycles. The drive operates intermittently to achieve positioning while the control system periodically checks for seizure conditions through pressure and angle monitoring. This periodic action pattern reduces cumulative exposure to axial overload and impact loading while maintaining adequate positioning accuracy through controlled engagement cycles
3Force
If the slew drive is designed with internal gearing for torque multiplication, then the output torque is improved, but the reliability deteriorates due to over/under driving causing lock-up
Solution Approach 1:
The control system uses feedback from pressure transducers and angle sensors to monitor the operational state of the internally geared slew drive. By detecting pressure anomalies and angular position deviations, the system identifies over/under driving conditions before they cause lock-up, allowing for corrective action that preserves the high output torque capability while preventing reliability issues
4Productivity
If the slew drive operates at high speed for productivity, then the productivity is improved, but the reliability deteriorates due to impact loading causing bearing and race failure
Solution Approach 1:
The control system performs preliminary detection of impact loading conditions by monitoring hydraulic pressure spikes and angular velocity changes during high-speed operation. When impact conditions are detected, the system preemptively reduces speed or reverses direction to prevent bearing and race failure, thereby maintaining high productivity through optimized speed management while protecting against component failure
Data Source
AI summary
A slew drive includes a bushing interfacing with a drive gear. The bushing resists a load from the drive gear. The bushing includes an aluminum bronze alloy with a high strength. A paving machine includes multiple of the slew drives. The slew drives control an angle of a pivot arm and steering of a track. A method of reducing component failure in the paving machine includes determining an angular position error of the slew drive of the track. If the angular position exceeds a tolerance, a rate-of-change of the angular position is found to determine whether the slew drive is rotating. Where the slew drive is not rotating, the slew drive is driven in a reverse direction to unseize the slew drive. A track drive and the slew drive of the pivot are controlled by a control loop. The slew drive may be dithered to steer a trailing pivot.