Slew Bearing Maintenance Access Without Crane Downtime
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Solution Overview
Problem
Large slew bearings require frequent inspection and maintenance, which leads to significant downtime as they need to be dismantled, disrupting the operation of supported structures like cranes and vessels.
Innovation Solution
The slew bearing design incorporates moveable and stationary rings with entry ports that allow for maintenance without rotating the bearing, enabling axial load rollers to be accessed and replaced without disassembly, using actuators to move the rings between operational and maintenance positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the slew bearing is dismantled for inspection and maintenance, then the bearing can be serviced, but the structure supported by the bearing becomes non-operational causing downtime
Solution Approach 1:
The slew bearing is divided into a stationary bearing ring and a moveable bearing ring that can be independently positioned. The moveable bearing ring can be moved between an operational position (engaged with axial load rollers) and a maintenance position (disengaged from rollers), allowing segmentation of the maintenance operation from the overall bearing system.
Solution Approach 2:
The moveable bearing ring is made dynamically positionable relative to the stationary bearing ring through actuators. This dynamic positioning capability allows the bearing to switch between operational and maintenance states without complete disassembly, enabling on-demand access to internal components while maintaining structural functionality.
2Ease of repair
If the moveable bearing ring is rotated to access axial load rollers, then rollers can be inspected, but the structure must be rotated causing operational disruption
Solution Approach 1:
The bearing ring is segmented into moveable and stationary portions, allowing the moveable portion to be independently positioned without rotating the entire bearing assembly. This segmentation enables access to axial load rollers through linear movement rather than rotational movement of the supported structure.
Solution Approach 2:
Instead of accessing axial load rollers through rotation in the horizontal plane, the invention enables access through vertical movement of the moveable bearing ring. This dimensional change from rotational access to vertical displacement access allows maintenance without rotating the supported structure.
3Device complexity
If actuators are made compact for the bearing design, then the overall bearing size is reduced, but the actuators must move the bearing ring over limited distance
Solution Approach 1:
The actuators perform only the partial action needed to move the moveable bearing ring between two discrete positions (operational and maintenance) rather than providing continuous rotational movement. This partial action approach allows for compact actuator design while achieving the necessary functionality.
Solution Approach 2:
The system uses dynamic positioning with actuators that provide controlled movement over limited distances between defined positions. This dynamic approach with limited stroke actuators achieves compact design while maintaining the ability to access bearing components for maintenance.
Data Source
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AI summary
The invention relates to a slew bearing comprising a stationary bearing ring to be fixed to a base, a moveable bearing ring to be fixed to a moveable object, wherein the stationary bearing ring and the moveable bearing ring are configured to enable rotation of the moveable bearing ring relative to the stationary bearing ring about a rotation axis. A main axial bearing and an auxiliary bearing are provided between the stationary bearing ring and the moveable bearing ring, wherein the moveable bearing ring comprises one or more main portions and one or more auxiliary portions, which one or more main portions are moveable relative to the one or more auxiliary portions between an operational position, in which the main axial bearing transfers the axial loads between moveable bearing ring and stationary bearing ring, and a raised maintenance position, in which the auxiliary axial bearing transfers the axial loads between moveable bearing ring and stationary bearing ring and the main bearing is allowed to be inspected and/or maintained so that the slew bearing during inspection and/or maintenance is still operational.