Multi-Row Gear Assembly With Material Joining for Tight Position Tolerance

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Solution Overview

Problem

Multi-row gears face challenges in meeting narrow shape and position tolerance criteria, and require complex production technologies, especially in aircraft engine planetary gear transmissions, where assembling and dismantling are difficult due to stringent geometric and positional requirements.

Innovation Solution

A method involving separate manufacturing of gear rims with integration through a material connection zone, allowing for precise positioning and alignment, using techniques like welding, soldering, or adhesive bonding, to form a two-row gear structure that meets tight tolerance criteria and allows for further processing to achieve optimal geometry and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multi-row gear rings are manufactured separately with tight form tolerances, then manufacturing flexibility and material selection are improved, but position tolerance criteria and centricity requirements become more difficult to meet

Engineering Contradiction:
Improvematerial selection flexibilityVSAvoidposition tolerance between gear rings
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The gear device is divided into multiple separately manufacturable gear rings that are subsequently joined together. Each gear ring can be manufactured independently with optimal material selection and form tolerances, while the segmentation enables separate production and assembly of complex multi-row gear structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A connection element is introduced as an intermediary component between the gear rings. This connection element serves as a mediator that facilitates precise positioning and alignment of the separately manufactured gear rings, enabling them to meet stringent position tolerance criteria through the intermediary's positioning features.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If gear components are assembled with complex position tolerance criteria, then mechanical operating behavior is improved, but manufacturing effort and design limitations increase considerably

Engineering Contradiction:
Improvemechanical operating behaviorVSAvoidmanufacturing effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Positioning features and alignment elements are incorporated into the design of the connection element before the actual assembly process. This preliminary design of positioning mechanisms ensures that when the gear rings are assembled, the required position tolerance criteria are automatically achieved, reducing the complexity of the assembly process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The connection element acts as an intermediary that pre-establishes the correct geometric relationships between gear rings. By designing this intermediary with integrated positioning features, the complex position tolerance requirements are built into the assembly structure itself, simplifying the manufacturing and assembly processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If gear teeth are designed for high strength requirements, then mechanical performance is improved, but machining of component areas outside tooth areas becomes difficult

Engineering Contradiction:
Improvegear tooth strengthVSAvoidmachinability of non-tooth areas
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The gear device is segmented into multiple gear rings that can be manufactured separately. This segmentation allows each gear ring to be optimized for its specific function - the tooth areas can be designed for high strength while the non-tooth areas can be designed for ease of machining and assembly, without compromising the overall structural integrity.

Inventive Principle:
Principle #1Segmentation

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

This approach enables the creation of gear devices with high positional accuracy and mechanical efficiency, reducing manufacturing complexities and enabling the use of various materials, including lightweight metals, while maintaining strength and operational performance.

Implementation Method 1

using techniques like welding, soldering, or adhesive bonding

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

using techniques like welding, soldering, or adhesive bonding

Methodology Applied
Scientific EffectSoldering: Soldering

Implementation Method 3

using techniques like welding, soldering, or adhesive bonding

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP4321776A1Multi-row gear wheel device and method and device for producing same
Publication Date: 2024.02.14 AREOSPACE TRASMISSION TECHNOLOGIES GMBH
  • EP4321776A1 patent drawingFigure 1
  • EP4321776A1 patent drawingFigure 2~3
  • EP4321776A1 patent drawingFigure 4

AI summary

The invention relates to a method and a device for manufacturing a gear assembly which, with respect to its toothing, is composed of several assembled component parts and comprises at least a first and a second gear ring, each manufactured separately as part of said component parts and, in particular, having helical teeth, wherein these two gear rings are arranged axially sequentially and thereby form a two-row gear structure. Furthermore, the invention also relates to a gear assembly with at least two rows, in particular helical teeth, which, in its assembled state, forms part of a planetary gear system, in particular a planetary gear system of an aircraft engine. The component parts are joined together by forming a material bond. The formation of this material bond is achieved in conjunction with a specific positioning of the component parts relative to one another.