Epicyclic Gearset Retaining Link for Planet Gear Interference Control
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Solution Overview
Problem
Conventional epicyclic gear trains are prone to malfunction due to damage in satellite wheels, leading to erratic deformation of the planet carrier and potential interference between planet gears, which can cause the gear train to fail and reduce service life.
Innovation Solution
An epicyclic gear train design featuring a retaining link that connects crankpins, allowing restricted movement and maintaining a predefined distance between them, which helps to absorb deformation and prevent interference, thereby enhancing the gear train's tolerance to damage and extending its service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If crankpins are rigidly fixed to the support, then the structure is simple and strong, but the planet carrier deforms erratically when a satellite wheel is damaged, causing interference between planet gears
Solution Approach 1:
The crankpin is designed with rotational freedom about its extension axis, transforming the rigid fixed connection into a dynamic joint that can adapt to deformation. This allows the crankpin to rotate relative to the support when a satellite wheel is damaged, preventing erratic deformation of the planet carrier and interference between planet gears, while maintaining structural strength during normal operation.
2Reliability
If crankpins are allowed free movement, then tolerance to damage increases, but the gear train malfunctions due to excessive deformation
Solution Approach 1:
The crankpin is constrained to rotate only about its extension axis rather than having free movement in all directions. This controlled rotational freedom allows the crankpin to accommodate satellite wheel damage by rotating to relieve stress, while the rotation is limited to a specific degree of freedom that maintains gear alignment and prevents excessive deformation of the planet carrier.
3Reliability
If a retaining link is added to connect crankpins, then tolerance to damage and service life are extended, but the device complexity increases
Solution Approach 1:
The retaining link is designed as a simple connector that joins multiple crankpins together, distributing the function of damage tolerance across multiple segments. Each crankpin remains an independent unit with rotational freedom, while the retaining link provides collective support. This segmentation allows the system to tolerate damage in individual satellite wheels without requiring complex redesign of the entire planet carrier structure.
Solution Approach 2:
The retaining link merges multiple crankpins into a connected assembly, creating a unified structure that shares deformation loads. When one satellite wheel is damaged, the retaining link distributes the stress across multiple crankpins, preventing localized failure and extending the service life of the gear train without requiring complex individual components.
Data Source
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AI summary
The present invention relates to an epicyclic gear train comprising several toothed planet wheels (30) which are carried by the same planet carrier (40), the planet carrier (40) comprising a support (45) and several crankpins (41) carried by said support (45), each crankpin (41) comprising a fixing section (42) which moves away from said support (45) to a distal end (43) in a direction (800), each planet wheel (30) being arranged around said fixing section (42) and having a degree of freedom in rotation about an extension axis (AX) of said fixing section (42). A retaining link (55) is carried by said crankpins (41) and connects the crankpins (41), each satellite wheel (30) being arranged in an area (95) between the support (45) and the retaining link (55), each crankpin (41) having a restricted freedom of movement relative to the retaining link (55).