Epicyclic Gear Train With Eccentric Planet Connectors for Backlash Elimination
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Solution Overview
Problem
Existing epicyclic gear trains face challenges in further reducing backlash, particularly due to wear over time, which affects precision in applications like industrial robots and solar power systems.
Innovation Solution
The epicyclic gear train incorporates rotatingly pre-tensioned planetary connectors with bearings, utilizing a central gear or individual springs to apply outward pressure on the planetary axis, allowing radial adjustment and compensation for ring gear variations, thereby eliminating backlash and ensuring precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If planetary connectors are made adjustable to reduce backlash, then positioning precision is improved, but device complexity increases
Solution Approach 1:
The planetary connectors are made dynamically adjustable through an eccentric connection mechanism. The connector can rotate around an axis offset from the planetary axis, allowing the distance between the central axis and planetary axis to be altered by turning the connector. This dynamic adjustment capability enables continuous optimization of meshing clearance to eliminate backlash while maintaining positioning precision.
Solution Approach 2:
A central gear acts as an intermediary element to simultaneously control multiple planetary connectors. The central gear meshes with control gears on each planetary connector, providing a unified mechanism to adjust all planetary axes radially. This intermediary structure simplifies the overall control system while achieving precise positioning across all planetary gears.
2Reliability
If planetary connectors are pre-tensioned to eliminate backlash, then reliability is improved, but device complexity increases
Solution Approach 1:
The planetary connectors are pre-tensioned using springs that apply a pressing force in the direction away from the central axis. This preliminary action ensures that the planetary gears maintain optimal meshing contact with ring gears from the outset, eliminating backlash before operation begins. The pre-tensioning force compensates for wear and variations during operation, ensuring continuous reliability.
Solution Approach 2:
The spring-based pre-tensioning mechanism is self-regulating and automatically compensates for wear and variations in the gear train. As components wear or conditions change, the spring maintains appropriate contact pressure without requiring external adjustment or intervention, providing continuous reliability through self-service operation.
3Measurement precision
If planetary axes are moved radially to compensate for variations, then positioning precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
Instead of requiring extremely precise static manufacturing, the system uses dynamic adjustment through rotatable planetary connectors with eccentric connections. This allows radial movement of planetary axes during operation to compensate for manufacturing variations and wear, reducing the stringency of initial manufacturing precision requirements while maintaining high positioning precision.
Solution Approach 2:
The system changes the operational parameters of the planetary gear train by allowing radial displacement of planetary axes. This parameter change enables compensation for manufacturing variations and wear, transforming a static precision problem into a dynamically adjustable system that maintains precision despite manufacturing tolerances.
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
This solution effectively reduces backlash and maintains precision over time by pre-tensioning the planetary connectors, ensuring accurate positioning and high gear ratios, even under varying conditions such as wear and temperature changes.
Implementation Method 1
The planetary connector of each planetary gear may comprise a spring, individually pre-tensioning the planetary connector
Implementation Method 2
Each planetary gear is attached to the planetary holder by means of a set of bearings
Data Source
Figure 1~2
Figure 3~4d
Figure 5~6
AI summary
The present disclosure relates to an epicyclic gear train comprising a driving pinion (3), driving a plurality of planetary gears (7). Each planetary gear is attached to a planetary holder and meshes with at least one ring gear. Thereby the ring gear or the planetary holder is made to rotate about a central axis (21) of the epicyclic gear train. The planetary gears (7) are attached to the planetary holder, each via at least one planetary connector (17) which is rotatable around an axis (24) offset from the planetary axis (23), such that turning said at least one planetary connector alters the distance between the central axis (21) and the planetary axis (23) by means of an excentric connection. The planetary connectors are rotatingly pre-tensioned to apply a pressure on the planetary axis (23) away from the central axis (21), and said at least one planetary connector is attached to the planetary holder by means of a bearing (27).