Ball Joint Housing with Local Thickening for Lower Stress
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Solution Overview
Problem
Current ball joints in gas turbine engines face limitations due to material constraints from manufacturing processes, leading to increased weight and stress concentrations, compromising system dynamic performance and requiring non-optimized thicknesses to support loads.
Innovation Solution
A ball joint configuration with local thickening in the housing, featuring reinforcement rings and ribbed patterns, which reduces stress levels, increases axial stiffness, and optimizes load distribution by allowing controlled rotation and flexure within predetermined angles while maintaining water tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If current ball joint configuration with quasi-constant thickness is used, then weight is increased, but structural strength is compromised requiring larger thicknesses
Solution Approach 1:
The patent applies local quality by implementing variable thickness distribution in the ball joint housing, with localized thickening at the pole regions (first and second poles) where stresses are highest, while maintaining thinner sections in less critical areas. This non-uniform thickness distribution optimizes structural strength at critical locations without unnecessarily increasing overall weight, directly resolving the contradiction between strength and weight.
2Ease of manufacture
If forming process is used for manufacturing ball joint components, then manufacturing ease is improved, but material selection is limited and tolerances are compromised
Solution Approach 1:
The patent employs parameter changes by transitioning from conventional forming processes to additive manufacturing (3D printing), which enables superior dimensional tolerances and broader material selection. This manufacturing method change allows precise control over complex geometries including the variable thickness profiles and internal reinforcement structures, achieving both manufacturing feasibility and high precision simultaneously.
3Strength
If large thicknesses are used to support loads, then structural strength is improved, but weight increases and stress concentrators are required
Solution Approach 1:
The patent applies segmentation by dividing the housing into distinct functional zones with different thickness characteristics: thickened pole regions for load bearing, thinner equatorial regions for weight reduction, and strategically placed reinforcement elements. This segmented approach allows each region to be optimized for its specific function, achieving overall load bearing capacity without requiring uniform large thickness throughout the entire structure.
Solution Approach 2:
The patent utilizes composite materials by combining different material properties in the ball joint construction, particularly in the thickened pole regions and reinforcement elements. The additive manufacturing process enables integration of materials with optimized mechanical properties that provide high strength-to-weight ratio, allowing the structure to bear loads efficiently without excessive weight or the need for stress concentrators.
Data Source
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Figure 3~3A
AI summary
The present invention relates to a ball joint 10 for connecting together two tubular portions (1, 2) of a duct assembly in a gas turbine engine and allows angular movement between these two tubular portions. More particularly, the invention relates to an improved configuration of ball joint provided with local thickening (6, 7) at corresponding overlapping inner and outer shrouds of a housing of the ball joint that significantly improves the mechanical properties of the ball joint. A bellow 3 is arranged inside the housing with limited flexure capacity.