Bearing Ring Grinding Profile for Wind Turbine Hard Zones
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Solution Overview
Problem
Wind turbine bearings suffer from accelerated fatigue damage due to 'local hard zones' caused by uneven loading, which limits their lifetime despite being manufactured to high precision using conventional machining techniques.
Innovation Solution
A method of identifying and removing material from local hard zones on the bearing ring surface through non-uniform grinding, reducing their area and extending the bearing's lifetime by 10%-30% by distributing roller and raceway loading more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional uniform grinding is applied to the bearing ring surface, then manufacturing precision is improved, but local hard zones are formed causing accelerated fatigue damage
Solution Approach 1:
The patent applies local quality by varying the grinding depth across different zones of the bearing ring. Specifically, the raceway surface is ground to different depths in different angular positions: deeper grinding in zones that will experience higher loads (to create material removal that compensates for plastic deformation) and shallower grinding in other zones. This creates a non-uniform surface profile that compensates for the non-uniform loading pattern, eliminating local hard zones while maintaining overall manufacturing precision.
2Reliability
If material is removed to reduce local hard zones, then bearing lifetime is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by calculating and planning the non-uniform grinding depths before the actual machining process. The method involves: (1) determining the loading pattern and identifying zones that will experience high loads, (2) calculating the required material removal depth for each zone based on elastic-plastic deformation theory, and (3) programming the grinding machine to execute this pre-calculated profile. This preliminary planning simplifies the actual machining process by converting a complex adaptive control problem into a straightforward execution of pre-determined parameters.
Solution Approach 2:
The patent replaces complex real-time mechanical measurement and adjustment systems with a calculation-based approach. Instead of using sensors and feedback control during grinding to detect and compensate for local hard zones, the method uses finite element analysis and elastic-plastic deformation calculations to predetermined the grinding profile. This substitution of mechanical feedback systems with computational methods reduces manufacturing complexity while achieving the same reliability improvement.
3Object-affected harmful factors
If bearing ring thickness is reduced in local hard zones, then fatigue damage is reduced, but structural strength may be compromised
Solution Approach 1:
The patent applies parameter changes by modifying the material removal depth parameter as a function of angular position around the bearing ring. The grinding depth is not uniform but varies continuously or in discrete steps according to the loading pattern. Specifically, the method calculates optimal grinding depths for different zones based on the expected load distribution, removing enough material in high-load zones to eliminate plastic deformation and local hard zones, while maintaining sufficient material thickness elsewhere to preserve overall structural strength.
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
The method effectively eliminates or reduces local hard zones, leading to a significant extension of the bearing's lifetime by ensuring even loading distribution and reducing fatigue damage, thereby enhancing the operational lifespan of wind turbine bearings.
Implementation Method 1
The surface that is being machined in this finishing step may be referred to simply as the 'machining surface' or 'grinding surface'... it may be assumed that a final finishing step involves grinding a surface of the bearing ring
Data Source
AI summary
Provided is a method of machining a bearing ring of a wind turbine bearing, the method including the steps of identifying a number of local hard zones on a surface of the bearing ring and removing material from the surface such that a bearing ring thickness in local hard zone is less than a bearing ring thickness outside a local hard zone. A machining assembly, a wind turbine bearing and a wind turbine is also provided.