Gearbox Retainer Axial Support for Planetary Carrier
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Solution Overview
Problem
Existing rotorcraft gearbox designs face challenges in supporting the planetary carrier in the axial direction without introducing additional bearings, which increases complexity, weight, and cost, and complicates assembly and maintenance, while designs with a unitary rotor mast and planetary carrier are difficult to manufacture, assemble, and maintain.
Innovation Solution
A retainer with a surface configured to support the planetary carrier is coupled to the rotor mast, using a threaded connection and contact surfaces to provide axial support, eliminating the need for dedicated carrier-support bearings and avoiding a unitary rotor mast with integral planetary carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carrier-support bearings are added to support the planetary carrier in the axial direction, then the planetary carrier is properly supported, but the device complexity, weight, and cost increase
Solution Approach 1:
The invention extracts the axial support function from the rotor mast itself and transfers it to a separate retainer component. The retainer is coupled to the rotor mast and provides the axial support surface for the planetary carrier, while the rotor mast focuses on torque transmission through its splines. This separation of functions reduces the complexity of the rotor mast design and allows each component to be optimized independently.
Solution Approach 2:
The retainer acts as an intermediary component between the rotor mast and the planetary carrier. It couples to the rotor mast and provides the axial support surface, mediating the interaction between these two components. This intermediary structure eliminates the need for carrier-support bearings while maintaining proper axial support.
2Reliability
If carrier-support bearings are added to support the planetary carrier, then axial support is provided, but weight increases
Solution Approach 1:
The invention removes the need for carrier-support bearings by extracting the axial support function and providing it through the retainer structure. This eliminates the weight of additional bearing components, keeping the gearbox lighter while maintaining proper axial support for the planetary carrier.
3Reliability
If a unitary rotor mast with integral planetary carrier is used, then axial support is provided, but manufacturing complexity and cost increase
Solution Approach 1:
The invention segments the rotor mast and planetary carrier into separate components, with the retainer providing the connection and axial support. This allows the rotor mast to be manufactured as a simpler component focused on torque transmission, while the planetary carrier is a separate assembly that can be manufactured and assembled independently. This segmentation greatly simplifies manufacturing compared to a unitary structure.
Solution Approach 2:
The retainer serves multiple functions: it couples the planetary carrier to the rotor mast and provides axial support. This multi-functional component eliminates the need for separate bearing assemblies and simplifies the overall structure, making manufacturing more economical while maintaining reliability.
4Reliability
If carrier-support bearings are added, then axial support is provided, but assembly and maintenance difficulty increase
Solution Approach 1:
By extracting the axial support function from the rotor mast and implementing it through the retainer, the invention simplifies assembly. The retainer can be installed as a single component that provides both coupling and axial support, eliminating the need to install and align separate carrier-support bearings, thereby reducing assembly complexity and maintenance requirements.
Data Source
AI summary
An apparatus and system for supporting a planetary carrier within an aircraft gearbox includes a retainer for engaging a rotor mast and for supporting the planetary carrier.