Planetary Gear Load Balancing via Eccentric Positioning
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Solution Overview
Problem
Conventional planetary gear sets in aircraft transmissions, such as those in helicopters, often experience load share imbalance due to manufacturing and assembly variations, leading to uneven wear and reduced service life, as well as increased noise and inefficiency.
Innovation Solution
A planetary gear arrangement with an actuated positioning element and control module that dynamically adjusts the position of planetary gears relative to the sun gear rotation axis, using eccentric couplings and sensors to balance load share by measuring real-time parameters like force, acceleration, and noise, thereby optimizing the distribution of torque across the gears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional planetary gear sets are used with fixed planetary gear positions, then the structure is simple and easy to manufacture, but load share imbalance occurs due to manufacturing and assembly variations leading to uneven wear and reduced service life
Solution Approach 1:
The patent applies the dynamics principle by making the planetary gear positions adjustable rather than fixed. The planetary gears can be dynamically repositioned along the sun gear rotation axis using positioning elements, allowing the system to adapt to load conditions and balance load share among gears, thereby improving reliability and service life while accepting increased structural complexity
Solution Approach 2:
The patent changes the positional parameter of planetary gears relative to the sun gear rotation axis. By adjusting the position of planetary gears along the rotation axis, the load distribution among gears can be optimized, transforming a static parameter into a variable one to achieve better load sharing and extended service life
2Reliability
If planetary gears are positioned to balance load share, then wear is reduced and service life is extended, but the system requires positioning elements and control mechanisms increasing complexity
Solution Approach 1:
The patent applies preliminary action by pre-positioning the planetary gears at optimized locations along the sun gear rotation axis during assembly or before operation. The positioning elements are pre-configured to place gears at positions that balance load share, reducing wear and extending service life while managing manufacturing complexity through advance preparation
3Productivity
If fixed planetary gear positions are used, then manufacturing is easier, but load share imbalance causes increased noise and reduced efficiency
Solution Approach 1:
The patent applies feedback by using sensors to detect operational parameters such as noise levels, vibration, or load distribution, and using this information to adjust the positions of planetary gears along the sun gear rotation axis. This closed-loop control optimizes transmission efficiency and reduces noise by dynamically balancing load share, accepting the added complexity of positioning mechanisms and control systems
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 achieves balanced load sharing among planetary gears, reducing noise, extending the service life of the gear set, and improving the overall efficiency of the transmission system by ensuring each gear carries an equal share of the load, even under varying operational conditions.
Implementation Method 1
The positioning element can include an eccentric coupling defining a planetary gear rotation axis. The eccentric coupling can be a first eccentric component, and the positioning element can include a second eccentric coupling. The first eccentric coupling can be seated in the second eccentric coupling, and the second eccentric coupling can be seated in the planet carrier.
Data Source
AI summary
A planetary gear arrangement includes a planet carrier assembly defining a sun gear rotation axis for rotatably supporting a plurality of planetary gears about the sun gear rotation axis and a positioning element coupling a first of the planetary gears to the planet carrier. The planetary gear is movable between first and second positions for displacing a rotation axis of the first of the planetary gears relative to the sun gear rotation axis to change load share among the plurality of planetary gears.