Aircraft Propeller Slip Ring Relocation for Wear Reduction
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Solution Overview
Problem
The existing propeller systems for aircraft experience high wear and maintenance needs due to the size of slip rings and exposure to contaminants like sand and dust, which affects the efficient transfer of electrical power to deicing components.
Innovation Solution
The slip ring assembly is relocated to the aft side of the gearbox, allowing for smaller diameter slip rings and reduced rotational speed, along with a wire transfer tube that isolates lead wires from oil flow, minimizing wear and protecting against contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slip rings are mounted forward of the gearbox in the brush block environment, then electrical power can be transferred to rotating components, but high wear occurs due to contaminants like sand and dust
Solution Approach 1:
The slip ring assembly is extracted from the contaminated brush block environment forward of the gearbox and relocated to a clean environment aft of the gearbox. This separation removes the slip rings from the harmful contaminant zone while maintaining their electrical power transfer function through the wire transfer tube mechanism.
Solution Approach 2:
A wire transfer tube is introduced as an intermediary component to bridge the rotational power transfer between the clean aft environment and the rotating propeller components. The wire transfer tube rotates with the propeller shaft while its lead wires remain stationary in the clean environment, mediating the power transfer without exposing slip rings to contaminants.
2Reliability
If standard sized slip rings are used in the brush block, then electrical power can be transferred to deicing components, but excessive maintenance is required due to brush wear
Solution Approach 1:
The slip ring assembly is extracted from the high-maintenance brush block environment and relocated to the clean aft environment. This eliminates the continuous contact and friction between carbon brushes and slip rings that occurred in the brush block, thereby reducing wear and maintenance requirements.
Solution Approach 2:
The traditional mechanical brush-slip ring contact system is replaced with an electrical wire transfer system. The wire transfer tube with stationary lead wires eliminates the need for sliding mechanical contact, substituting a wear-free electrical connection mechanism for the high-wear mechanical system.
3Power
If slip rings are placed in the brush block environment, then power can be transferred to rotating components, but the size of slip rings increases wear and maintenance needs
Solution Approach 1:
The power transfer system transitions from a radial slip ring contact geometry to a linear wire transfer tube geometry. The lead wires extend axially along the rotation axis rather than radially from the slip ring face, changing the dimensional arrangement to eliminate wear while maintaining power transfer capability.
Data Source
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AI summary
A propeller system (10) for an aircraft includes a propeller assembly rotatable about a central axis (28) and a reduction gearbox (16) operably connected to the propeller assembly via a propeller shaft (18). An electrical power transfer system is positioned such that the gearbox (16) is located axially between the electrical power transfer system and the propeller assembly. The electrical power transfer system includes a slip ring assembly (40) secured to an oil transfer tube (24) extending to the propeller assembly and a brush block (34) interactive with the slip ring assembly (40) to transfer electrical power to a plurality of lead wires (50) extending from the slip ring assembly (40) to the propeller assembly. The brush block (34) is positioned such that brush block tips (46) of the brush block (34) extend toward the slip ring assembly (40) in a substantially radial direction relative to the central axis (18) of the propeller assembly.