Planet Carrier Cheek Layout for Torsional Alignment Control
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Solution Overview
Problem
Conventional planetary carriers with two cheeks experience significant torsion under load, making it difficult to suppress relative rotation between the cheeks, which can lead to misalignment of the planetary axis due to varying torsional stiffness.
Innovation Solution
A planetary carrier design with differentiated 'inner' and 'outer' cheeks, where the inner cheek supports the drive-side planetary axle ends and is connected to the drive-side hub, and the outer cheek is connected to the webs, allowing for separate adjustment of torsional stiffness of the inner and outer load paths to ensure synchronized rotation of axle seats under load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the thickness of the sides or webs is increased to suppress torsion, then the torsional stiffness is improved, but the weight of the planet carrier increases
Solution Approach 1:
The planet carrier is divided into two separate cheeks (drive-side cheek and driven-side cheek) connected by webs, allowing independent optimization of each component's torsional characteristics. This segmentation enables the drive-side cheek to be designed with higher torsional stiffness while the driven-side cheek can be lighter, resolving the contradiction between overall stiffness and weight reduction.
Solution Approach 2:
Different regions of the planet carrier are given different thicknesses and structural characteristics. The drive-side cheek is designed with greater thickness and stiffness where torsional loads are highest, while the driven-side cheek and connecting webs are optimized for weight reduction. This local differentiation allows the structure to achieve necessary stiffness only where required, rather than uniformly increasing weight throughout.
2Manufacturing precision
If the planet carrier is designed with a single solid structure to maintain alignment, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The planet carrier is segmented into multiple components (cheeks and webs) that are assembled together. This segmentation reduces manufacturing complexity by allowing each component to be manufactured separately with standard tolerances, then assembled to achieve the required overall alignment precision, rather than requiring a single complex casting or forging operation.
Solution Approach 2:
The webs serve as intermediary elements connecting the drive-side and driven-side cheeks. These webs are designed with specific geometric features and connection details that facilitate precise alignment during assembly. The intermediary structure provides reference surfaces and mounting features that ensure accurate relative positioning of the cheeks, achieving manufacturing precision through the assembly process rather than requiring a monolithic structure.
Data Source
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AI summary
The invention relates to a planet carrier comprising a drive-side hub (1), a drive-side outer web (2a), a driven-side web (5), and at least one web (4) connecting the two said webs (2a, 5). The driven-side web (5) has at least one driven-side axle seat (6b) for each driven-side end of a planetary shaft. The planet carrier also has a drive-side inner web (8) which is arranged parallel to the drive-side outer web (2a) and has at least one drive-side axle seat (6a) for each drive-side end of a planetary shaft.