Backlash-Free Planetary Transmission via Roller Rolling Mesh
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Solution Overview
Problem
Existing planetary transmission devices face challenges in eliminating backlash, reducing transmission noise, and improving efficiency due to sliding friction between gear teeth, leading to mechanical vibration, noise, and reduced accuracy and reliability.
Innovation Solution
A backlash-free planetary transmission device is designed with a dual-gear arrangement featuring bevel gears and rollers that allow for pure rolling mesh, eliminating sliding friction and enabling zero transmission error and backlash, with a manufacturing process that includes rolling bearings and elastic collars for stability and ease of assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a double-disc conical cycloid wheel planetary transmission device is used to eliminate backlash, then transmission accuracy is improved, but sliding friction between teeth increases causing higher energy consumption and reduced efficiency
Solution Approach 1:
The patent replaces the traditional cycloid wheel teeth meshing mechanism with a roller-based mechanism. Instead of tooth-to-tooth contact that causes sliding friction, the invention uses rollers that rotate on their axes to achieve pure rolling contact. This substitution eliminates the sliding friction component while maintaining the backlash-free transmission accuracy, thereby reducing energy consumption and improving transmission efficiency.
Solution Approach 2:
The patent changes the fundamental contact parameter between mating elements from sliding contact to rolling contact. By introducing rollers with rotating capability, the contact mode parameter is transformed, which eliminates sliding friction while preserving the precise positioning and backlash-free characteristics of the original cycloid mechanism.
2Device complexity
If traditional gear pair transmission is adopted, then the structure is simple, but meshing backlash cannot be eliminated reducing transmission precision
Solution Approach 1:
The patent segments the traditional single gear pair into a dual-gear system with rollers. Each roller is treated as an independent element that can rotate on its axis, dividing the contact function into multiple rolling contact points. This segmentation enables backlash-free transmission while maintaining relative structural simplicity through modular roller components.
3Manufacturing precision
If backlash elimination mechanisms are implemented, then transmission accuracy improves, but the mechanism becomes more complex increasing manufacturing difficulty
Solution Approach 1:
The rollers in the patent are designed to rotate on their own axes, providing self-adjusting capability. This self-service feature automatically compensates for any manufacturing tolerances or wear, maintaining transmission accuracy without requiring complex adjustment mechanisms or high-precision manufacturing processes for the entire system.
4Manufacturing precision
If sliding friction is present between teeth, then backlash can be eliminated, but wearing between components increases reducing service life
Solution Approach 1:
The patent substitutes the sliding friction mechanism with a rolling friction mechanism by introducing rotatable rollers. This replacement eliminates the wear-causing sliding contact while preserving the backlash-free transmission characteristic, thereby significantly extending the service life of the transmission components.
Solution Approach 2:
The patent converts the harmful sliding friction into beneficial rolling friction. By allowing rollers to rotate, the originally harmful sliding contact is transformed into rolling contact, which generates less wear and heat, thereby extending component life while maintaining the backlash elimination benefit.
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 achieves high accuracy, low noise, and extended service life by eliminating backlash and jamming, while reducing wear and enhancing transmission efficiency through pure rolling mesh and balanced axial forces.
Implementation Method 1
The pin teeth of both the fixed pin gear and the power output pin gear include a roller that can rotate around its own axis. The outer surface of the roller is a teeth surface. The profiles of teeth of the two outer gears of the dual outer gear are respectively enveloped by profiles of the fixed pin gear and the power output pin gear meshed therewith.
Implementation Method 2
The outer ring of the power output shaft rotatably fits with the housing via a rolling bearing I.
Implementation Method 3
The dual conical outer gear is positioned around the outer ring of the eccentric sleeve with a rolling bearing II and rotatably fits therewith.
Implementation Method 4
The power output shaft is positioned around the outer ring of the power input shaft with a rolling bearing III and rotatably fits therewith.
Implementation Method 5
An outer collar slot on the housing is embedded with an outer elastic collar on the outer side of the bearing outer ring of the rolling bearing I. An inner collar slot on an outer ring is embedded with an inner elastic collar on the outer side of the bearing inner ring of the rolling bearing I.
Data Source
AI summary
A backlash-free planetary transmission device includes an outer ring of an eccentric sleeve rotatably fitted with a dual outer gear. One outer gear of the dual outer gear is meshed with a fixed pin gear with small teeth number difference, and the other outer gear is meshed with a power output pin gear with small teeth number difference. Each of the fixed pin gear and power output pin gear includes a roller. Profiles of teeth of the outer gears are respectively enveloped by profiles of the fixed pin gear and power output pin gear meshed therewith. The outer gears and rollers are in rolling mesh, to avoid sliding friction between meshed gear teeth. The dual outer gear contacts with the fixed pin gear and power output pin gear, with zero transmission error and zero backlash. The transmission device has high accuracy, low noise, high transmission efficiency, and long service life.