Offset Recess Bearing Hub for Reciprocating Compressor
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Solution Overview
Problem
Conventional radial bearing arrangements for reciprocating refrigeration compressors experience significant viscous friction losses, which complicate and increase the cost of grinding processes due to unbalanced crankshafts and shape errors, while existing solutions either require complex operations or fail to maximize reduction in axial extension of radial bearing regions.
Innovation Solution
A bearing arrangement with a bearing hub and crankshaft featuring circumferential recesses that are axially offset, allowing for reduced axial extensions of radial bearing regions while maintaining adequate support for the crankshaft, enabling efficient surface finishing operations and minimizing viscous friction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the axial extension of radial bearing regions is reduced to minimize viscous friction losses, then energy efficiency is improved, but the crankshaft becomes unbalanced causing shape errors and complicating grinding processes
Solution Approach 1:
The bearing hub is segmented into multiple bearing portions (first, second, and third) separated by circumferential recesses. This segmentation allows the radial bearing regions to be divided into distinct zones, enabling reduced axial extension in each region while maintaining proper lubrication pockets and hydrodynamic support. The segmentation resolves the contradiction by creating discrete bearing zones that minimize friction without compromising crankshaft balance or manufacturing precision.
Solution Approach 2:
Different regions of the bearing hub are given different properties through the circumferential recesses that create varying axial extensions. The first bearing portion has different characteristics than the second and third portions, with each optimized for its specific loading and lubrication requirements. This local differentiation allows minimal axial extension in critical areas while maintaining adequate support where needed, resolving the contradiction between energy efficiency and manufacturing precision.
2Loss of energy
If circumferential recesses are provided in the bearing hub to reduce viscous friction, then mechanical losses are reduced, but the device complexity increases
Solution Approach 1:
The bearing hub is divided into multiple bearing portions by circumferential recesses, creating a segmented structure that reduces viscous friction in each zone. While this segmentation increases structural complexity, it enables significant reductions in mechanical losses by eliminating continuous radial bearing surfaces that generate high friction. The complexity is justified by the substantial energy efficiency improvements.
Solution Approach 2:
The circumferential recesses change the geometric parameters of the bearing hub, creating variations in axial extension across different regions. This parameter modification allows the bearing hub to adapt its geometry to minimize viscous friction losses while maintaining functional requirements. The parameter changes resolve the contradiction by optimizing the balance between structural complexity and energy efficiency.
3Power
If the axial extension of radial bearing regions is minimized, then power dissipation is reduced, but adequate support for the crankshaft is compromised
Solution Approach 1:
The radial bearing regions are segmented into multiple portions with circumferential recesses creating distinct zones. Each segment provides localized support while the cumulative effect of multiple segments maintains adequate overall crankshaft support. This segmentation allows minimal axial extension in each region, reducing power dissipation while preserving reliability through distributed support zones.
Solution Approach 2:
The circumferential recesses act as intermediaries between bearing portions, creating lubrication pockets that facilitate hydrodynamic support. These intermediary regions enable the bearing hub to maintain adequate crankshaft support with reduced axial extension by utilizing fluid film lubrication in the recess zones, resolving the contradiction between power dissipation and reliability.
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 proposed arrangement achieves reduced viscous dissipation and maintains reliable surface finishing capabilities, with radial bearing regions dimensioned to minimize mechanical losses while ensuring sufficient axial extensions for effective bearing and grinding operations.
Implementation Method 1
presenting smaller viscous friction losses in relation to the known bearing arrangements
Implementation Method 2
the regions of the end portions 30a, 30b of the bearing hub 30, which regions effectively have the function of radially bearing the crankshaft 40
Data Source
AI summary
The arrangement of the present invention is applied to a compressor which comprises a bearing hub housing a crankshaft and presenting at least a first and a second bearing portion, spaced apart by a circumferential recess. The crankshaft presents at least a first and a second support portion, spaced apart by a circumferential recess, which is offset from the circumferential recess of the bearing hub. At least one of the bearing portions and support portions has an axial extension superior to that required for radially bearing the crankshaft, the first and second bearing portions defining, with the first and second support portions, respectively, a first and a second radial bearing regions having the axial extensions required for a radial bearing for the crankshaft, presenting lower loss by viscous friction.