Rolling Bearing Lubricant Loop Circuit to Prevent Stagnation
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Solution Overview
Problem
Conventional bearings in gas generators and turbomachines require external lubrication systems, which degrade engine performance, increase costs, and lead to lubricant stagnation in dead zones, making recirculation unreliable.
Innovation Solution
A self-lubricated bearing with a loop circuit for forced lubricant recirculation, where rolling elements create a pump effect by rolling over orifices, eliminating the need for external pumping systems and utilizing centrifugal force to prevent lubricant stagnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external lubrication system with pump and distribution circuit is used, then reliable lubrication is achieved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The invention extracts and eliminates the external lubrication system (pump, distribution circuit, valves, solenoids) from the bearing system. Instead, the lubrication function is integrated directly into the bearing structure itself through internal channels and recirculation paths, thereby reducing device complexity while maintaining lubrication reliability
Solution Approach 2:
The bearing becomes self-lubricating through an internal recirculation system where lubricant is distributed via centrifugal force and gravity, then recaptured and reused through internal channels. This eliminates the need for external pumping systems and complex control components, achieving both simplicity and reliability
2Reliability
If an external pumping system is used for lubricant recirculation, then lubricant recirculation is achieved, but mass and manufacturing cost increase
Solution Approach 1:
The invention replaces the mechanical pumping system with a passive recirculation mechanism utilizing centrifugal force generated by bearing rotation and gravity. Lubricant is thrown outward by centrifugal force, then recaptured and returned through internal channels without requiring any additional moving parts or power consumption, thereby eliminating the mass of external pumping equipment
Solution Approach 2:
The bearing system performs its own lubricant recirculation using the rotational energy already present in the system. The centrifugal force generated by normal operation is sufficient to distribute and recirculate lubricant through internal channels, eliminating the need for separate pumping systems and reducing overall mass
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
Reduces the number of components, operational and manufacturing costs, and mass, while ensuring reliable lubricant recirculation and preventing lubricant stagnation, enhancing engine performance and reliability.
Implementation Method 1
This configuration offers the advantage of generating lubricant recirculation through a pumping effect. This pumping effect is achieved because the circuit opens directly onto at least one of the bearing raceways. The rolling elements move over the circuit outlets, forcing the lubricant present on the raceway to be injected into the inlet(s).
Implementation Method 2
The invention makes it possible to take advantage of centrifugal force, which in prior art self-lubricating bearings tends to throw lubricant towards dead zones on the non-rotating outer part of the bearing, where the lubricant remains trapped and stagnates. The centrifugal force is all the greater as the rotational speed of the inner part of the bearing increases.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Rolling-element bearing for a turbomachine of an aircraft, comprising an inner ring (3) defining a first raceway (112), and an outer ring (4) defining a second raceway (124), characterized in that the bearing has at least one loop circuit (21, 22) for forced recirculation of lubricant, this loop circuit comprising a first recirculation circuit (21) comprising at least one lubricant inlet (1200) located on the second raceway (124), and connected by at least one duct (120, 166) created in the outer ring (4) to at least one lubricant outlet (1661) which discharges into a second recirculation circuit (22) of the loop circuit (21, 22), this second recirculation circuit (22) comprising at least one duct (152, 1134, 1136; 1135, 1136) created in the inner ring (3).