Non-Circular Journal Pin for Epicyclic Gearbox Lubrication
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Solution Overview
Problem
Epicyclical gearboxes face issues with lubrication in journal bearings due to inadequate hydrodynamic oil flow, leading to wear and tear, especially under high pressure conditions, where the lubrication 'wedge' fails to form, causing direct contact between the journal pin and bearing body.
Innovation Solution
A non-circular shaped journal pin is designed to mimic the shape of the journal bearing body, particularly at high pressure points, allowing for free flow of lubricating fluid and maintaining lubrication even under deformation, thus preventing direct contact and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional circular journal pin is used in the journal bearing, then the structure is simple and easy to manufacture, but under high pressure the lubrication wedge fails to form causing direct contact and wear between the journal pin and bearing body
Solution Approach 1:
The journal pin is designed with an asymmetric non-circular cross-section that mimics the deformed shape of the journal bearing body under high pressure. This asymmetric geometry creates a wedge-shaped lubrication chamber that maintains effective lubrication by preventing direct contact between the journal pin and bearing body, even under high pressure conditions where conventional circular pins fail.
Solution Approach 2:
The journal pin geometry is changed from a conventional circular cross-section to a non-circular cross-section with specific dimensional parameters that match the deformed bearing body shape. This parameter change transforms the lubrication mechanism by creating a wedge effect that maintains fluid film lubrication under high pressure, preventing metal-to-metal contact and reducing wear.
2Force
If the journal bearing operates under high pressure conditions, then power transmission capability is improved, but the lubrication wedge collapses causing direct contact and increased wear
Solution Approach 1:
The non-circular asymmetric cross-section of the journal pin is specifically designed to match the deformed shape of the bearing body under high pressure. This asymmetric geometry creates a wedge-shaped clearance that maintains lubrication film stability even under high load conditions, preventing the collapse of the lubrication wedge that occurs with conventional circular pins.
Solution Approach 2:
The journal pin geometry is designed to dynamically adapt to the high pressure conditions by maintaining a wedge-shaped lubrication chamber that prevents direct contact. The non-circular cross-section creates a dynamic lubrication regime where the wedge effect continuously maintains film separation between the journal pin and bearing body, ensuring reliable lubrication under varying load conditions.
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 ensures continuous lubrication within the bearing, reducing wear and tear, and maintaining the integrity of gearbox components by facilitating hydrodynamic oil flow, even at high pressure points.
Implementation Method 1
A lack of hydrodynamic lubricating fluid flow between the body of each of the bearing and the associated journal pin may result in a lack of lubrication within the bearing and planet gear that may result in direct contact between the journal pin and the journal bearing body
Data Source
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AI summary
A journal bearing for use in an epicyclical gearbox including a non-circular shaped journal pin and a journal bearing body into which the non-circular shaped journal pin is disposed. The non-circular shaped journal pin configured to mimic the shape of the non-cylindrical shaped journal bearing body at least at a high pressure point exerted upon the non-cylindrical shaped journal bearing body during a high pressure event, thereby permitting a free flow of a lubricating fluid there between the non-circular shaped journal pin and the journal bearing body during the high pressure event. An epicyclical gearbox including the journal bearing and method of facilitating a hydrodynamic oil flow in the planet gear journal bearing.