Anti-backlash Planetary Gearing for Fiber Optic Rotary Joints
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Solution Overview
Problem
Precision planetary gear systems in multi-channel fiber optical rotary joints face issues with motion loss, noise, and vibration due to backlash between gears, and existing anti-backlash solutions are either bulky, complex, or costly.
Innovation Solution
A compact anti-backlash apparatus for planetary gear trains using a spring-loaded elastomeric annular ring to eliminate backlash between gear teeth, with a 2:1 gear ratio design that includes a spherical feature on planet gear housing and elastomeric sleeves for load balancing, allowing for precise kinematic transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spring bias apparatus is used to eliminate backlash, then kinematic transmission accuracy is improved, but device complexity and required space increase
Solution Approach 1:
The patent combines the anti-backlash function with the planet gear structure by integrating spring-loaded elastomeric annular rings directly into the planet gear assembly. The elastomeric rings are positioned between the planet gear teeth and the sun gear, merging the backlash elimination mechanism with the gear transmission components themselves, thereby reducing overall device complexity while maintaining high kinematic transmission accuracy.
Solution Approach 2:
The patent uses simple spring-loaded elastomeric annular rings instead of complex hydraulic or electric adjustment mechanisms. These elastomeric components are inexpensive, easy to manufacture, and can be easily replaced if needed, providing a cost-effective solution for eliminating backlash without requiring sophisticated anti-backlash apparatus.
2Manufacturing precision
If hydraulic piston system is used to maintain clearance filling positioning, then backlash is eliminated, but device complexity and cost increase significantly
Solution Approach 1:
The patent replaces complex hydraulic piston systems with a purely mechanical spring-loaded elastomeric ring mechanism. The springs provide continuous contact force between the elastomeric rings and gear teeth, maintaining clearance-filled positioning through simple mechanical means rather than requiring hydraulic actuators, control systems, or expensive adjustment mechanisms.
Solution Approach 2:
The spring-loaded elastomeric annular rings automatically maintain clearance filling positioning through their inherent elastic properties. The springs continuously apply force to keep the elastomeric rings pressed against the gear teeth, providing self-regulating backlash elimination without requiring external control systems, hydraulic pressure, or manual adjustment mechanisms.
3Manufacturing precision
If large diameter twin gear is used for spring bias assembly, then backlash elimination is achieved, but overall gear system size increases
Solution Approach 1:
The patent nests the elastomeric annular rings within the planet gear structure, positioning them in the space between the planet gear teeth and the sun gear. This nested arrangement allows the anti-backlash mechanism to be integrated within the existing gear geometry rather than requiring larger external gears, maintaining compact overall system size while achieving effective backlash elimination.
Solution Approach 2:
The patent addresses backlash in the radial dimension by using elastomeric rings that deform radially to fill clearances, rather than increasing gear diameter in the tangential dimension. The spring-loaded elastomeric rings compress radially to eliminate backlash, allowing compact gear dimensions while achieving precision anti-backlash performance.
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 solution provides low-profile, high-accuracy kinematic transmission with reduced noise and vibration, enhancing the performance of multi-channel fiber optic rotary joints by eliminating backlash and maintaining precision.
Implementation Method 1
spring-loaded elastomeric annular ring to eliminate backlash between gear teeth
Implementation Method 2
elastomeric sleeves for load balancing
Data Source
AI summary
The invention includes a precision planetary gear system which requires 2:1 gear ratio. The planetary gear system consists of three, or more planet gear assemblies. By adding a local degree of freedom, the planet gear assembly could be tilted relative to the carrier by a spring-loaded annular ring through a spherical feature thus force the three, or more planet gear assemblies symmetrically mesh into the sun gear and internal gear. A couple of elastomeric sleeves are introduced into the connection between the planet housing and the carrier so as to balance the load evenly among the three planet assemblies and to reduce the speed fluctuation of transmitted motion as well as the noise and vibration.