Epicyclic Gear Oil Supply via Stacked Pressure Drop Elements
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Solution Overview
Problem
Conventional planetary gear reducers in turbomachines face challenges in maintaining oil supply during failures, particularly in preventing seizing of plain bearings, due to difficulties in producing and controlling small diameter fluid channels and the risk of clogging by particles.
Innovation Solution
A device comprising a series of stacked elements with fluid passage channels, each with a pressure drop, and a secondary oil supply system in the planet carrier that utilizes centrifugal force to redirect oil flow through main and secondary channels, ensuring continuous oil supply and trapping particles to prevent clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a small diameter channel is used to limit the flow rate of oil, then the oil supply duration is extended, but the channel is liable to be blocked by particles contained in the oil circuit
Solution Approach 1:
The patent divides the single long narrow channel into multiple shorter parallel channels. This segmentation maintains the total flow resistance needed to extend oil supply duration while avoiding the particle blockage risk associated with long narrow channels. The multiple parallel paths ensure that if particles are present, they cannot block all channels simultaneously.
Solution Approach 2:
The patent introduces a centrifugal separator as an intermediary device between the oil reservoir and the lubrication channels. This separator removes particles from the oil before it enters the lubrication channels, preventing blockage while allowing the channels to maintain dimensions suitable for extended oil supply duration.
2Duration of action of moving object
If a strainer is placed at the entrance to the channel to limit the flow rate, then the oil supply duration is extended, but the strainer is at risk of clogging by particles
Solution Approach 1:
The patent replaces the strainer with a centrifugal separator that uses centrifugal force to remove particles. This intermediary device effectively separates particles from oil without creating a narrow passage that can clog, thereby extending oil supply duration while maintaining reliability.
Solution Approach 2:
The patent replaces the mechanical filtration system (strainer) with a centrifugal separation system. This substitution eliminates the clogging problem inherent in mechanical filters while achieving the same goal of limiting oil flow rate to extend supply duration.
3Duration of action of moving object
If accumulators are formed in the planet carrier to supply oil during breakdown, then the oil supply duration is extended, but the structure becomes difficult to produce and increases dimensions and mass
Solution Approach 1:
The patent makes the planet carrier serve multiple functions: it acts as both the rotating component that carries the lubrication channels and as the containment structure for the oil reservoir. This eliminates the need for separate accumulator structures, simplifying production and reducing overall dimensions and mass while maintaining extended oil supply capability.
Solution Approach 2:
The patent merges the oil reservoir and the lubrication channel system into a single integrated structure within the planet carrier. By combining these functions, the design avoids the complexity and additional mass that would result from separate accumulator components, while still providing extended oil supply during breakdown.
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 provides a reliable and efficient oil supply to prevent seizing of plain bearings during turbomachine operation failures, allowing sufficient time for auxiliary pump startup or shutdown while avoiding channel blockages by particles.
Implementation Method 1
a device forming a fluid circulation channel capable of generating a pressure drop
Implementation Method 2
a so-called low zone, spaced from the axis of rotation of the planet carrier, a so-called upper zone, close to the axis of rotation of the planet carrier
Data Source
AI summary
The invention relates to an epicyclic reduction gear, notably for a turbomachine, equipped with a device forming a fluid circulation passage (20a, 20b) able to generate a pressure drop, created by stacking at least two elements (22). Each element (22) comprises a passage (27) for carrying fluid able to generate a pressure drop and comprising an inlet (28) and an outlet (29). The outlet (29), or inlet (28), of the passage (27) of one of the elements (22) is, respectively, connected to the inlet (28), or to the outlet (29), of the passage (27) of the other element (22).