Composite Gear Web With Tuned Compliance for Tooth Load Distribution
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Solution Overview
Problem
Conventional gear tooth flank corrections require accurate machining techniques, limiting the use of cost-effective machine tools and are often specific to a particular use case, restricting the gear system's effectiveness in varying conditions.
Innovation Solution
A composite gear design featuring a metallic gear rim and a composite web with oriented fibers, providing variable compliance and reduced stiffness, allowing for cost-effective manufacturing without permanent alterations, and enhancing performance across different operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional gear tooth flank correction shaping is applied, then gear tooth contact pressure is reduced and strain in root radius is minimized, but accurate machining techniques are required which limit the use of cost-effective machine tools
Solution Approach 1:
The patent changes the material parameter from homogeneous metal to composite material with varying fiber orientations. The fiber orientation angles (0°, 45°, 90°, -45°) in different zones of the gear body allow tuning of mechanical properties to achieve optimal contact pressure distribution without requiring precision machining of tooth flanks.
Solution Approach 2:
The patent employs composite materials with strategically oriented fibers to replace conventional metal gears. The composite structure provides tailored stiffness and compliance in different directions, achieving the effect of tooth flank correction through material design rather than geometric shaping, thereby enabling use of cost-effective manufacturing processes.
2Reliability
If gear tooth flank correction shaping is applied, then performance is optimized for a particular use case, but the gear tooth form becomes permanently altered and cannot be adapted to other use cases
Solution Approach 1:
The patent introduces adaptability through variable fiber orientation patterns that can be configured for different operating conditions. The composite gear body can be designed with gradient fiber orientations or interchangeable composite inserts that allow the gear to adapt its mechanical characteristics based on loading conditions, speed, and torque requirements.
Solution Approach 2:
The patent applies different fiber orientations and material properties in specific zones of the gear body tailored to local stress conditions. This allows optimization for particular use cases while maintaining the ability to reconfigure or replace zones for different applications, providing localized adaptability without permanently altering the entire gear form.
3Ease of manufacture
If conventional metal gear design is used, then manufacturing is straightforward, but mass is higher and compliance is reduced
Solution Approach 1:
The patent replaces dense metal materials with composite materials that have lower density, directly reducing gear mass. The composite structure maintains sufficient strength and stiffness through strategic fiber orientation, achieving weight reduction without sacrificing mechanical performance.
Solution Approach 2:
The patent changes the material density parameter from high (metal) to low (composite), and adjusts fiber orientation parameters to maintain mechanical properties. This allows achieving lower mass while preserving the compliance and strength required for gear operation.
4Strength
If rigid gear tooth structure is used, then strength is high, but compliance is reduced leading to increased contact pressure
Solution Approach 1:
The patent applies different fiber orientations in different zones of the gear tooth structure. The root zone uses fibers oriented to provide high strength and stiffness, while the tooth flank zones use fibers oriented to provide appropriate compliance for load distribution. This local differentiation achieves both high strength and adequate compliance simultaneously.
Solution Approach 2:
The patent uses composite materials with anisotropic properties to achieve direction-dependent mechanical characteristics. The fiber reinforcement provides high strength in the load-bearing direction while the matrix material and fiber architecture provide compliance in directions that facilitate load distribution and stress relief.
Data Source
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AI summary
A composite gear (100) includes an annular metallic gear hub (102) including a bore (104) and defining a central axis (106) of the composite gear (100). The composite gear (100) includes a composite web (108) disposed circumferentially around the annular metallic gear hub (102) with respect to the central axis (106). The composite gear (10) includes a metallic gear rim (112) disposed circumferentially around the composite web (108) with respect to the central axis (106). The metallic gear rim (112) includes an annular portion (114) disposed adjacent to the composite web (108) and a plurality of gear teeth (116) angularly spaced apart from each other with respect to the central axis (106) and extending outwardly from the annular portion (114) distal to the composite web (108). The composite gear (100) includes an interface (118) disposed between the metallic gear rim (112) and composite web (108). The composite web (108) has a plurality of fibres (110) comprising a set of first fibres (110A) and a set of second fibres (110B) intersecting with the set of first fibres (110A) and inclined to the set of first fibres (110A) by an inclination angle (110C) from 30 degrees to 60 degrees, such that the set of first fibres (110A) and the set of second fibres (110B) together form a mesh (110D) or a woven fabric (110E).