Beveloid Planetary Gear with Spring Backlash Compensation
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Solution Overview
Problem
Existing planetary gears are not sufficiently precise, have limited gear ratio, and suffer from backlashes, making them unsuitable for applications requiring accurate torque transmission and compactness in robotic mechanical arms.
Innovation Solution
A compact planetary gear design featuring a fixed annular gear, planet carrier with beveloid teeth, and a backlash adjustment system, which includes a spring mechanism to ensure precise angular position transfer and minimize axial backlashes, while maintaining stiffness and reducing weight and assembly costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional planetary gears with bevel gears are used, then torque transmission is achieved, but precision and gear ratio are limited due to backlashes between gears
Solution Approach 1:
The planetary gear is divided into multiple independent planet gears (typically 3-4) that can be individually adjusted. Each planet gear has its own adjustment mechanism allowing separate backlash compensation, which enables high precision angular position transfer without requiring a completely complex monolithic structure
Solution Approach 2:
The patent employs adjustable and adaptable planet gear positions through mechanisms such as adjustable planet gear carriers or individual planet gear positioning. This dynamic adjustment capability allows the system to compensate for manufacturing tolerances and maintain precision while managing structural complexity
2Reliability
If bevel gears with spring axial thrust system are used to limit backlashes, then gear contact is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The adjustment mechanisms for multiple planet gears are merged into a single integrated system. A unified adjustment mechanism simultaneously controls the positioning of all planet gears, ensuring consistent gear contact stability while dramatically simplifying the manufacturing and assembly process compared to individual adjustment mechanisms for each gear
Solution Approach 2:
The spring axial thrust system is designed to automatically maintain optimal gear contact through self-adjusting mechanisms. The springs provide continuous axial force that compensates for wear and tolerance variations without requiring external adjustment, thereby improving reliability while maintaining ease of manufacture
3Measurement precision
If precision planetary gears are designed for robotic arms, then positioning accuracy improves, but weight and dimensions may increase
Solution Approach 1:
The planetary gear components utilize composite material structures, such as hollow planet gears or gears with optimized material distribution. This allows maintaining high positioning accuracy through precise tooth geometry while reducing the overall weight of the moving gear components for use in robotic arms
Solution Approach 2:
The patent employs optimized gear geometry in multiple dimensions, such as tapered planet gears or non-uniform tooth distribution. This dimensional optimization enables achieving high positioning accuracy through improved angular resolution while keeping the overall gear dimensions and weight minimized for robotic applications
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 achieves high precision, compactness, and reduced backlashes, enabling quick accelerations and high positioning accuracy with competitive performance compared to traditional planetary gears.
Implementation Method 1
an axial thrust system with a spring, which keeps the teeth of the bevel gears in contact with one another
Data Source
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AI summary
A precision planetary gear comprising: a pinion (I; 2; 102); a movable annular gear (IV; 25); a fixed annular gear (III; 9); one or more planet gears (II; 19; 219); wherein each planet gear (II; 19; 219) simultaneously meshes with the pinion (I; 2; 102), the fixed annular gear (III; 9) and the movable annular gear (IV; 25); the pinion (I; 2; 102) comprising a gear with a beveloid toothing; each planet gear (II; 19; 219) comprising a gear with a beveloid toothing; wherein a beveloid toothing has a correction (x), which linearly varies along the longitudinal direction of the tooth (Z); wherein each tooth (Z) of the beveloid toothing has a thickness (s) and a height (h) which increase moving from the apex (V) of said beveloid gear along the longitudinal direction of the tooth (Z ).