Planetary Gear Shaft Structure for Carrier Deformation Compensation
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Solution Overview
Problem
Existing planetary gears in turbomachines face issues with deformation of the planet carrier leading to misalignment of planet wheels, resulting in performance deterioration and premature wear of teeth, which is compounded by the complexity and cost of using additional shims to prevent misalignment.
Innovation Solution
A planetary gear design featuring an annular space between radially inner and outer cylindrical parts allows controlled deformation of the shaft flange to compensate for planet carrier deformations, maintaining gear performance and preventing tooth wear without the need for additional shims.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high torque is transmitted through the planetary gear, then power transmission capability is improved, but the planet carrier deforms causing satellite misalignment and gear performance deterioration
Solution Approach 1:
The shaft is divided into two independent cylindrical parts (first radially inner cylindrical part and second radially outer cylindrical part) that can deform independently. This segmentation allows each part to accommodate deformation without causing misalignment of the satellite, thereby maintaining gear performance under high torque conditions.
Solution Approach 2:
The patent introduces an annular space between the two cylindrical parts of the shaft, allowing controlled deformation through parameter changes in the shaft's structural configuration. This enables the shaft to absorb deformation from planet carrier flexion without transmitting misalignment to the satellite gears, resolving the contradiction between power transmission and gear reliability.
2Reliability
If shims are placed between the satellites to prevent misalignment, then gear performance is maintained, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent eliminates the need for additional shims by incorporating the deformation compensation function directly into the shaft's dual cylindrical part structure. The annular space between the two cylindrical parts provides the necessary compliance without requiring separate shim components, thereby reducing device complexity while maintaining gear performance.
Solution Approach 2:
The shaft's own structure (with its two cylindrical parts and annular space) provides the deformation compensation function that would otherwise require external shims. The shaft serves itself by accommodating planet carrier deformation internally, eliminating the need for additional alignment components and simplifying the overall device structure.
3Stability of the object's composition
If the planet carrier is made more rigid to prevent deformation, then alignment stability is improved, but the ability to absorb torque-induced stress decreases
Solution Approach 1:
The patent introduces controlled flexibility into the shaft through the annular space between its two cylindrical parts. This dynamic structure allows the shaft to deform in response to planet carrier flexion under torque, absorbing stress while maintaining satellite alignment through the coordinated deformation of the two cylindrical parts, thus achieving both adaptability and stability.
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
The design effectively transmits high torque while maintaining gear performance and preventing premature wear of teeth, reducing complexity and cost by allowing controlled deformation of the planet carrier and shafts.
Implementation Method 1
Such a structure allows controlled deformation of the shaft, at the level of the flange, of the cylindrical parts or of the connection zone, so as to compensate for the deformations of the planet carrier
Data Source
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AI summary
The invention relates to a planetary gear train (1) comprising a first planetary gear (2), a second planetary gear (3), planetary gears (4) engaging with the first planetary gear (2) and with the second planetary gear (3), each planetary gear (4) being mounted for pivoting about a shaft (5), a planetary gear carrier (6) supporting each shaft (5), characterised in that each shaft (5) extends along an axis (B) and comprises a radially internal cylindrical portion (18) which is mounted on the planetary gear carrier (6), a radially external cylindrical portion (19) about which the planetary gear (4) is mounted for pivoting and an end plate (20) which extends radially from the radially external cylindrical portion (19), the radially external periphery of the end plate (20) being mounted on the planetary gear carrier (6), the radially external cylindrical portion (19) and the radially internal cylindrical portion (18) being connected to each other by a connection zone (24) which extends radially.