Full-Floating Bearing Groove Geometry for Wear and Whirl Noise
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Solution Overview
Problem
The circumferential groove on the outer peripheral surface of full-floating bearings in turbochargers reduces the surface area, making them more prone to wear and increasing the likelihood of whirl noise, which is difficult to address with existing designs.
Innovation Solution
A bearing design with chamfered portions at both ends and an outer peripheral groove with a specific width and depth ratio, along with an inner peripheral groove, is implemented to balance surface area reduction and noise suppression, optimizing the groove dimensions to reduce wear and whirl noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a circumferential groove is formed in the outer peripheral surface of the full-floating bearing to suppress whirl noise, then whirl noise is reduced, but the surface area of the outer peripheral surface is reduced, making the bearing more liable to wear
Solution Approach 1:
The invention changes the geometric parameters of the circumferential groove by specifying precise relationships between groove width, chamfer width, and bearing width (where the groove width minus chamfer width divided by bearing width is 0.1 or more but less than 0.5). This parameter optimization allows the groove to effectively suppress whirl noise while minimizing the reduction of load-bearing surface area, thereby resolving the contradiction between noise suppression and wear resistance
Solution Approach 2:
The invention applies different structural features to different regions of the bearing: chamfered portions are formed at both ends of the outer peripheral surface to reduce stress concentration and prevent groove end wear, while the circumferential groove in the middle region suppresses whirl noise. This localized differentiation allows each region to perform its specific function optimally without compromising overall bearing reliability
2Object-generated harmful factors
If the groove width is increased to improve noise suppression effect, then whirl noise is reduced, but the net width of the bearing is reduced, increasing wear
Solution Approach 1:
The invention establishes specific parameter relationships where the groove width is controlled relative to the bearing width and chamfer width, ensuring that the ratio (groove width - chamfer width) / bearing width falls within 0.1 to 0.5. This parameter optimization balances the groove's noise suppression capability with the preservation of sufficient load-bearing net width, preventing excessive wear while maintaining effective whirl noise reduction
Data Source
AI summary
A full-floating bearing includes: an outer peripheral groove having a groove width larger than a value of 0.69, which is a value obtained by subtracting a chamfer width as a width of a chamfered portions in a center axis direction and the groove width as a width of the groove in the center axis direction from a total width being a width of a main body in the center axis direction and dividing a net width by a total width.