Journal Sleeve Weight Reduction via Local Quality and Dimensionality
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Solution Overview
Problem
Conventional hydrodynamic fluid film journal bearings have thick cylindrical journal sleeves that add significant weight, which is a critical design concern, especially in aerospace applications, and can cause damage to O-rings during assembly.
Innovation Solution
A journal sleeve with reduced wall thickness in specific regions, featuring a grooved design with frusto-conical tapered portions and chamfered regions to minimize weight and prevent O-ring damage, along with O-ring lands for engagement, allowing for a tailored profile that maintains structural integrity and facilitates smooth assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the journal sleeve wall thickness is increased to provide stiffness, then the structural integrity is improved, but the weight of the bearing increases significantly
Solution Approach 1:
The journal sleeve employs varying wall thickness along its length, with thicker sections at the ends and a reduced thickness in the middle section. This local quality variation provides sufficient structural integrity at the ends while reducing overall weight, resolving the contradiction between strength and weight.
Solution Approach 2:
The invention transitions from a uniform cylindrical geometry to a more complex three-dimensional profile with varying wall thickness. This dimensional change allows the sleeve to maintain strength where needed while reducing material usage and weight in less critical areas.
2Weight of stationary object
If the journal sleeve wall thickness is reduced to decrease weight, then the bearing weight is reduced, but the structural integrity and stiffness deteriorate
Solution Approach 1:
The journal sleeve employs varying wall thickness along its length, with thicker sections at the ends and a reduced thickness in the middle section. This local quality variation provides sufficient structural integrity at the ends while reducing overall weight, resolving the contradiction between strength and weight.
3Ease of manufacture
If the journal sleeve has a uniform cylindrical shape, then the manufacturing is simplified, but the weight is excessive and O-rings may be damaged during assembly
Solution Approach 1:
The journal sleeve employs varying wall thickness along its length, with thicker sections at the ends and a reduced thickness in the middle section. This local quality variation provides sufficient structural integrity at the ends while reducing overall weight, resolving the contradiction between strength and weight.
Solution Approach 2:
The chamfered regions with tapered portions provide curved transition surfaces that guide O-rings during assembly, preventing damage while maintaining manufacturing feasibility. This geometric modification balances manufacturing ease with assembly safety and weight reduction.
4Weight of stationary object
If the journal sleeve wall thickness is reduced with grooves and tapered portions, then the weight is reduced and assembly is facilitated, but the manufacturing complexity increases
Solution Approach 1:
The journal sleeve is segmented into distinct regions with different wall thicknesses - thicker end sections and a thinner middle section separated by grooves. This segmentation allows weight reduction in critical areas while maintaining structural integrity, balancing complexity and performance.
Solution Approach 2:
The chamfered regions with tapered portions provide curved transition surfaces that guide O-rings during assembly, preventing damage while maintaining manufacturing feasibility. This geometric modification balances manufacturing ease with assembly safety and weight reduction.
Data Source
Figure 1
Figure 2
AI summary
A hydrodynamic fluid film journal bearing system (10) includes a journal sleeve (12) and one or more hydrodynamic fluid film foils positioned at least partially within the journal sleeve. The journal sleeve defines an inner diameter surface, an outer diameter surface (14), a wall thickness between the inner and outer diameter surfaces, and opposite first (18) and second (20) ends. The wall thickness of the journal sleeve is reduced at a first region located between the first and second ends, and a chamfered region (66) is formed on the outer diameter surface of the journal sleeve between a first o-ring land (62) and the first end (18) of the journal sleeve (12).