Aircraft Reduction Gear Assembly Marking for Uniform Tooth Load
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Solution Overview
Problem
Existing mechanical gearboxes in aircraft turbomachines face challenges in ensuring precise alignment of teeth, leading to potential overload and uneven load distribution during operation, particularly in multi-stage coaxial gearboxes where non-alignment can result in cumbersome architectures or operational failures.
Innovation Solution
A method of manufacturing mechanical reduction gears involving assembly marking, where specific teeth on central and satellite gears are marked to ensure precise angular positioning, allowing for uniform load distribution and improved alignment through identical marking patterns on each gear, ensuring all satellite gears are identical and correctly positioned relative to the central pinion and external ring gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional assembly methods without marking are used, then assembly process is simpler and faster, but tooth alignment precision deteriorates leading to uneven load distribution
Solution Approach 1:
The patent applies preliminary action by marking specific teeth on the sun gear, planet gears, and ring gear before assembly. These markings serve as pre-established reference points that guide the assembly process, ensuring precise angular positioning of satellite gears relative to the central pinion without requiring complex alignment procedures during assembly.
Solution Approach 2:
The patent uses copying by creating identical marking patterns on multiple satellite gears. Each satellite gear receives the same angular positioning markings, allowing them to be assembled in interchangeable positions while maintaining consistent load distribution. The markings are copied across all satellite gears to ensure uniformity in their angular orientation.
2Reliability
If satellite gears are not precisely aligned, then assembly is easier, but load distribution becomes uneven causing overload on individual teeth
Solution Approach 1:
The marking of reference teeth on all gears before assembly allows workers to quickly identify correct angular positions without requiring complex measurement tools or adjustment procedures during assembly, maintaining ease of manufacture while ensuring reliable load distribution.
Solution Approach 2:
The patent uses visual markings (analogous to color changes) on the gear teeth to indicate correct angular positioning. These distinctive marks provide immediate visual feedback during assembly, allowing workers to achieve proper alignment through simple visual matching rather than complex measurement, thereby ensuring uniform load distribution while maintaining assembly simplicity.
3Reliability
If multiple-stage gearboxes are designed with proper alignment, then operational reliability improves, but design complexity increases
Solution Approach 1:
The patent applies preliminary action at the design stage by pre-calculating and pre-marking the angular positions of teeth that ensure proper alignment in multi-stage configurations. This allows complex multi-stage gearboxes to achieve reliable operation without requiring complex adjustment mechanisms, as the correct positioning is built into the component design itself through the marking system.
Data Source
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AI summary
Method of manufacturing a mechanical reducer (1) for an aircraft turbomachine comprising a central pinion (40), an outer ring (50), N planetary pinions (100, 200, 300), where N≥3, each planetary pinion comprising a first stage (110, 210, 310) meshing with the central pinion (40), and a second stage (120, 220, 320) meshing with the outer ring (50), the method comprising the assembly marking, in which N teeth of the central pinion (40) are marked, and N pairs of teeth (111) of the first stage of each planetary pinion are marked, the N planetary pinions each being marked identically, and the assembly of the mechanical reducer, such that the teeth of the marked pairs of teeth (111) of the first stage of each planetary pinion are arranged on either side of a marked tooth of the central pinion.