Two-Shell Planet Carrier Cage for Turbomachine Satellite Assembly

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Solution Overview

Problem

The assembly of satellites in a turbomachine speed reducer's planet carrier can be challenging due to the need to cut the cage into multiple parts, and existing solutions result in cumbersome and heavy flanges that are difficult to implement effectively.

Innovation Solution

The planet carrier design features a cage with two shells, where the housings for mounting connecting elements are formed in both shells, allowing each shell to support forces and reduce the need for large flanges, enabling a more efficient and economical assembly process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the cage is dissociated into multiple parts to enable satellite assembly, then the assembly process becomes feasible, but the structure becomes cumbersome and heavy due to required flanges and fastening means

Engineering Contradiction:
Improvesatellite assembly feasibilityVSAvoidcage weight
Core Design Contradiction:
Ease of manufactureVSWeight of stationary object

Solution Approach 1:

The cage is divided into two separate shells that can be assembled independently. The satellites are assembled within the internal cavity formed by these two shells, allowing satellite installation without requiring the entire cage to be disassembled. This segmentation enables feasible satellite assembly while avoiding the need for heavy external flanges and fastening means that would otherwise be required to open the cage structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two cage shells are designed to form an internal cavity that contains and protects the satellites during assembly. The satellites are nested within this cavity formed by the two shells, allowing them to be installed in a controlled environment before the cage is fully closed. This nesting approach eliminates the need for cumbersome external fastening structures.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Strength

If large flanges and constrained fastening means are used to support 50% of the reducer load, then structural strength is sufficient, but the device complexity and weight increase significantly

Engineering Contradiction:
Improveload bearing capacityVSAvoidflange and fastening structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The load-bearing function is distributed to the two cage shells themselves rather than being concentrated in separate heavy flanges. Each shell is designed to support a portion of the reducer load (at least 50% collectively), eliminating the need for additional large flanges and complex fastening structures. The shells' inherent structural design provides the necessary strength while maintaining simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two cage shells serve multiple functions simultaneously: they form the containment cavity for satellite assembly, provide structural strength to bear at least 50% of the reducer load, and eliminate the need for separate flanges and fastening means. This multi-functionality reduces overall device complexity while maintaining required load-bearing capacity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4108900B1Planet carrier for a speed reducer of an aircraft turbine engine
Publication Date: 2023.08.23 SAFRAN TRANSMISSION SYST

AI summary

Planet carrier (213) for a turbomachine (1) speed reducer (210), said planet carrier (213) having a principal X-axis and comprising: - a cage carrier (222) having an annular row of axial fingers (282) around the X-axis, which carry first connecting elements, and - a cage (220) having at its periphery housings (280) and second connecting elements which are mounted in said housings (280) and which cooperate with the first connecting elements to form connections between the cage carrier (222) and the cage (220), which allow at least one degree of freedom, characterized in that the cage (220) comprises two shells (220a, 220b) which are axially fixed to each other and separated from each other by a plane (P1), said housings (280) being formed respectively in said shells (220a, 220b).