Planet Carrier Pivot Curvature for Misalignment Load Distribution
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Solution Overview
Problem
Existing planet carrier designs with sliding pivot connections in turbomachines experience misalignment issues, leading to concentrated contact pressure and stress concentrations at the ends of pivots, which can cause poor distribution of forces and potential structural damage.
Innovation Solution
The planet carrier design incorporates pivots with convex, rounded external surfaces or orifices with matching convex internal surfaces, allowing the contact pressure to be distributed away from the ends, reducing misalignment-induced stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sliding pivot connections with cylindrical surfaces are used in planet carrier designs, then the structure is simple and easy to manufacture, but misalignment occurs leading to concentrated contact pressure and stress concentrations at the ends of pivots
Solution Approach 1:
The patent applies curvature by replacing the cylindrical pivot surface with a convex rounded surface. The external surface of the pivot or the internal surface of the orifice has a convex shape in axial section, which allows contact pressure to be distributed along the curved surface rather than concentrated at the ends. This curved geometry maintains manufacturing feasibility while eliminating the misalignment-induced stress concentration problem.
2Strength
If rigid connections between carrier frame and carrier frame holder are used, then structural strength is improved, but flexibility to accommodate misalignment is lost
Solution Approach 1:
The patent implements a dynamic solution by allowing the pivot to slide within the orifice along the radial direction. This sliding capability provides flexibility to accommodate misalignment while maintaining structural strength through the rigid pivot-orifice connection. The dynamic adjustment enables the system to adapt to varying alignment conditions without sacrificing overall structural integrity.
Data Source
AI summary
A planet carrier for a reduction gear of a turbomachine includes a carrier frame having at its periphery axial housings distributed about the axis, a carrier frame holder with axial fingers distributed about the axis and engaged in the axial housings, and connecting elements connecting the fingers to walls of said housings. Each of the connecting elements has a pivot extending in a radial direction relative to the axis, and being borne by one of the members and having an external surface which in axial section has a convex shape and which collaborates with a cylindrical internal surface of an orifice of the other of these members.