Thin-Section Scanner Bearing Damping for Vibration and Noise
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Solution Overview
Problem
Thin section bearings in gantry assemblies for machines like luggage security scanners and CT scanners experience significant vibration and noise due to their large diameter and minimal radial thickness, which conventional bearings cannot effectively mitigate.
Innovation Solution
The implementation of a thin section bearing assembly with an outer and inner ring, each with a high diameter-to-thickness ratio, and a plurality of rolling elements, along with elastomeric annular dampers between the rings and the housing/rotor, which are designed to absorb bending moments and reduce vibrations by varying compression based on applied angles, thereby increasing fatigue life and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If thin section bearings with large diameter and minimal radial thickness are used in gantry assemblies, then the bearing size and rotational capability are improved, but vibration and noise levels increase significantly
Solution Approach 1:
The patent changes the physical parameters of the bearing system by introducing elastomeric dampers with specific durometer hardness (40-90 Shore A) and dimensional ratios. The damper radial thickness is set to 0.01 to 0.05 times the bearing outer ring radial thickness, and the axial width is set to 0.5 to 2.0 times the bearing outer ring axial width, optimizing the damping effect while maintaining rotational capability
Solution Approach 2:
The elastomeric annular damper acts as an intermediary element positioned between the bearing outer ring and the housing, and between the bearing inner ring and the rotor. This mediator absorbs and dissipates vibration energy through elastic deformation, reducing the transmission of harmful vibrations and noise while allowing the bearing to maintain its rotational function
2Object-generated harmful factors
If elastomeric dampers are added to reduce vibration, then vibration and noise are reduced, but the device complexity increases
Solution Approach 1:
The patent employs flexible elastomeric annular dampers in the form of thin-walled structures with specific geometric ratios. The damper radial thickness is designed as 0.01 to 0.05 times the bearing outer ring radial thickness, creating a thin-film flexible structure that provides effective vibration damping while adding minimal structural complexity and maintaining a compact design
3Object-generated harmful factors
If the damper compression varies significantly under bending moments, then vibration damping is improved, but the damper fatigue life decreases
Solution Approach 1:
The elastomeric annular damper is segmented into multiple circumferential sections that are positioned around the bearing ring. This segmentation allows each section to independently deform and recover under bending moments, distributing the mechanical stress more evenly across all sections. The segmented structure enables effective vibration damping through localized compression while preventing any single section from experiencing excessive cumulative damage, thereby extending the overall damper fatigue life
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 solution effectively reduces vibrations and noise in gantry assemblies by optimizing the elastomeric dampers' design to support radial loads and rotate at high speeds, enhancing the bearing's fatigue life and operational stability.
Implementation Method 1
at least one elastomeric annular damper disposed between the outer ring and the housing and/or between the inner ring and the rotor
Implementation Method 2
The at least one elastomeric annular damper has a first section and a second section spaced axially apart from the first section. As such, a compression of the first section is greater than a compression of the second section when a bending moment is applied to the bearing assembly
Data Source
AI summary
A thin section bearing assembly is for a gantry assembly and includes inner and outer rings each having inner and outer circumferential surfaces and rolling elements grooves and are each sized such that a ratio of the inside diameter to radial thickness is at least thirty (30). A plurality of rolling elements, preferably balls, are disposed between the outer ring groove and the inner ring groove. At least one elastomeric annular damper is disposed between the outer ring and the housing and/or between the inner ring and the rotor and has first and second axially spaced sections. As such, the first section is compressed more than the second section under bending moments in a first angular direction and the second section is compressed more than the first section under moments in a second angular direction. The one or more annular dampers each have a thickness calculated to optimize vibration reduction.