Structural Bearing Fatigue Testing With Cam-Driven Radial Loading
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Solution Overview
Problem
Existing methods for structural fatigue life testing of bearings, particularly thin-walled bearings, result in material waste, high machining difficulties, performance inconsistencies, and increased production costs due to the use of a large, slender, thin-walled cylinder structure and integral flange, which are difficult to cut and machine, and require complex heat treatment.
Innovation Solution
A method using a load collar with a substantially annular structure, independently formed, applies a rotational dynamic strain pressure load to the bearing through elastic deformation, synchronized with a cam-induced radial expansion, and a holding mechanism provides rotation-resistant support to ensure accurate testing without preventing the application of the test load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large, slender, thin-walled cylinder structure with integral flange is used for the loading device, then the positioning support is sufficient, but the machining difficulty increases significantly and material waste occurs
Solution Approach 1:
The loading device is divided into separate components: the main body and the flange are no longer formed as one integral structure. This segmentation allows each part to be manufactured independently with optimized processes, reducing machining difficulty while maintaining positioning support functionality.
Solution Approach 2:
The flange is extracted as a separate component from the main body of the loading device. This extraction enables the main body to be manufactured with simpler processes suitable for thin-walled structures, while the flange can be manufactured separately and assembled, thereby reducing overall machining difficulty and material waste.
2Device complexity
If a slender, thin-walled cylinder structure is used for the loading device, then the device complexity is reduced, but the heat treatment process becomes difficult to ensure consistent material performance
Solution Approach 1:
By segmenting the loading device into separate components, each component can undergo heat treatment independently with optimized parameters. This avoids the difficulty of ensuring uniform heat treatment across a large, slender, thin-walled integral structure, thereby improving material performance consistency.
3Length of moving object
If the fixed end is positioned close to the open end, then the device length is reduced, but the free deformation of the open end is adversely affected
Solution Approach 1:
The segmentation of the loading device allows for optimized positioning of functional components. The fixed end and open end can be positioned at appropriate distances to ensure free deformation of the open end, while the overall device length is minimized through compact arrangement of segmented components.
4Reliability
If the entire loading device is discarded after the open end fails, then the testing function is maintained, but material waste increases significantly
Solution Approach 1:
The loading device is designed as a segmented structure where only the open end (loading collar) is subject to fatigue failure. The main body and flange, which provide positioning support, remain intact and can be reused. This segmentation enables partial replacement of the loading device, significantly reducing material waste while maintaining testing function.
Solution Approach 2:
Instead of discarding the entire loading device after open end failure, the invention allows recovery and reuse of the main body and flange components. Only the worn loading collar needs to be replaced, embodying the discarding and recovering principle to reduce material waste.
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
This approach simplifies machining, reduces costs, and allows for customized testing, making the structural fatigue life test of bearings economical and accurate, while enabling retrofitting of conventional test rigs with low modification difficulty and cost advantages.
Implementation Method 1
the loading device to deform synchronously with the expansion, thereby applying, together with the cam, a rotational dynamic strain pressure load, mainly in the radial direction in both inward and outward directions, to the bearing, based on the elasticity of the loading device itself
Data Source
AI summary
A method for conducting structural fatigue life testing of a bearing, in which a cam embedded in the bearing under test generates a rotational dynamic radial expansion and transmits the expansion through the bearing to a load collar compactly mounted on the periphery of the bearing, forcing the load collar to deform synchronously with the expansion, thereby applying, together with the cam, a rotational dynamic strain pressure load, mainly in the radial direction in both inward and outward directions, to the bearing, based on the elasticity of the load collar itself, as a test load for the structural fatigue life testing of the bearing. Based on the above method, the present invention also provides a holding mechanism that provides a rotation-resistant support for the load collar and a bearing rotation test rig capable of assembling the holding mechanism.