Preloaded Helical Planetary Gear Assembly for Backlash Reduction
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Solution Overview
Problem
Planetary gears experience backlash issues when wheels change rotational direction, leading to uneven motion profiles and unwanted wear due to the lack of consistent contact between gearings.
Innovation Solution
The implementation of a planetary gear design featuring preloaded double planets with helical gearings, where force exerting elements ensure continuous contact between the gearings, minimizing backlash by applying preload in both rotational directions, and using an even number of double planets for balanced force distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If helical gearings are used in planetary wheels, then smooth operation and reduced noise are achieved, but backlash occurs when rotational direction changes causing uneven motion profiles and wear
Solution Approach 1:
The patent applies preliminary action by preloading the double planet wheels against the hollow wheels using force exerting elements (springs) before operation begins. This preliminary force ensures that the gear flanks are already in contact and maintaining contact during direction changes, preventing backlash from occurring in the first place rather than correcting it after it occurs.
Solution Approach 2:
The patent changes the force parameter by introducing spring elements that continuously apply a preload force to the gearings. This parameter change ensures that the contact force between gear flanks remains non-zero during direction changes, transforming the gear contact from intermittent to continuous and eliminating backlash.
2Reliability
If force exerting elements are added to eliminate backlash, then contact between gearings is maintained, but device complexity increases
Solution Approach 1:
The patent merges the force exerting element (spring) directly into the double planet wheel assembly, combining the preload function with the existing structural components. This integration approach minimizes additional complexity by utilizing the available space and structural elements within the planetary gear mechanism rather than adding completely separate components.
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 design effectively reduces backlash and improves stability by maintaining contact between gearings during operation, preventing uneven motion profiles and wear, while allowing for efficient movement transfer between input and output wheels.
Implementation Method 1
a first force exerting element is provided. The first force exerting element exerts a first force in the first direction so that the first side faces of the helical gearings of the first wheel of the first double planet are in contact with the second side faces of the helical gearings of the first hollow wheel
Data Source
AI summary
A planetary gear is disclosed that provides at least a first hollow wheel with a helical gearing and a second hollow wheel with a helical gearing are adapted to rotate in a first rotational direction and a second opposite rotational direction, and a first double planet having a first wheel with a helical gearing meshing with the helical gearing of the first hollow wheel and having a second wheel with a helical gearing meshing with the helical gearing of the second hollow wheel. The disclosed configuration minimizes backlash between the helical gearings.