Single-Row Bearing With Alternate Load Path for Extreme Loads
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Solution Overview
Problem
Wind turbines face premature bearing failures due to extreme loads, which are costly and difficult to repair, especially since traditional bearings require factory replacement or labor-intensive on-site repair, and existing double or triple row bearings are expensive.
Innovation Solution
A single row bearing design with an alternate load path that engages during extreme loads, featuring shoulders or additional load-carrying elements that divert load directly from the outer to the inner race, reducing stress on rolling elements and allowing for lower cost and weight while maintaining reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional single row bearings are used in wind turbines, then the bearing design is simple and cost-effective, but the bearing fails prematurely under extreme loads
Solution Approach 1:
The bearing structure dynamically switches between two load paths based on load conditions: during normal operation, loads are transmitted through the rolling elements (balls/rollers) for low-friction operation; during extreme loads, the alternate load path engages where loads are transmitted directly between inner and outer raceways through contact at the raceway surfaces, bypassing the rolling elements. This dynamic adaptation allows the bearing to maintain reliability under varying load conditions without requiring a permanently complex structure.
Solution Approach 2:
The bearing is segmented into two distinct load transmission paths: the primary load path through rolling elements and the alternate load path through direct raceway contact. This segmentation allows each path to be optimized for its specific function - rolling elements for normal loads and direct contact for extreme loads - resolving the contradiction between simplicity and reliability.
2Reliability
If double or triple row bearings are used to handle extreme loads, then bearing reliability under extreme loads improves, but the bearing cost increases significantly
Solution Approach 1:
Instead of using complex multi-row bearings permanently, the invention uses a single row bearing with a dynamic alternate load path that only engages during extreme loads. The bearing transitions from a simple single-row design during normal operation to an effective multi-row configuration during extreme loads, achieving high reliability without the permanent cost and manufacturing complexity of actual multi-row bearings.
3Reliability
If bearings are replaced at the factory, then bearing replacement reliability is ensured, but turbine downtime and repair costs increase
Solution Approach 1:
The bearing design incorporates an alternate load path that acts as a protective mechanism against extreme loads before they cause failure. By providing this backup load path in advance, the bearing can withstand extreme conditions without premature failure, ensuring that when replacement is eventually needed, it can be done as a planned maintenance activity rather than an emergency repair, reducing downtime and allowing for proper preparation.
4Ease of manufacture
If bearing size and weight are reduced for cost and weight savings, then manufacturing cost and turbine weight decrease, but bearing load capacity is compromised
Solution Approach 1:
The bearing uses a dynamic load path switching mechanism that allows a smaller, lighter single-row bearing to handle both normal and extreme loads. During normal operation, the bearing operates as a lightweight single-row design. During extreme loads, the alternate load path engages, effectively providing the load capacity of a much larger multi-row bearing without the weight and cost penalty, thus resolving the contradiction between size/weight reduction and load capacity maintenance.
Data Source
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AI summary
A bearing (500) is provided having a first race (505), a second race (515) and one or more rolling elements (510). The bearing includes an alternate load path (530) for extreme loads, and the alternate load path is formed between the first race (505) and the second race (515). At least a portion of the extreme loads is diverted away from the rolling elements (510).