Configurable Planetary Gearbox for Low Noise Work Vehicle Reduction
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Solution Overview
Problem
Existing gearbox reductions in work vehicles, when paired with e-machines, result in high noise levels due to transmission errors, and lack design flexibility and cost-effectiveness, particularly in providing low noise and long operational lifespan.
Innovation Solution
A high contact ratio, configurable gearbox reduction using a planetary gear train with specific tooth count relationships between the ring gear, sun gear, and planet gears, ensuring at least two teeth of each gear contact in all positions, reducing transmission errors and allowing modular design for various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional gearbox reductions are used with e-machines, then speed reduction is achieved, but noise levels increase due to transmission errors
Solution Approach 1:
The patent applies parameter changes by carefully selecting the tooth counts of ring gear (Tring), sun gear (Tsun), and planet gears (Tplanet) to achieve a high contact ratio. This ensures that at least two teeth of each gear are in contact at all times, which smooths power transmission and reduces transmission errors that cause noise. The mathematical relationships between tooth counts (Tring + Tsun divisible by different numbers from set {3,4,5}) create optimized gear meshing conditions that minimize vibration and noise while maintaining speed reduction functionality.
2Ease of manufacture
If standard gearbox designs are used, then manufacturing is straightforward, but design flexibility and cost-effectiveness are limited
Solution Approach 1:
The patent achieves universality through the configurable planetary gear train design where the mathematical relationships between tooth counts enable the same basic gearbox structure to accommodate multiple gear ratios and applications. The planet-carrier assembly can be configured with different numbers of planet gears (3, 4, or 5) while maintaining compatibility with the ring and sun gears, allowing a single gearbox housing design to serve multiple speed reduction requirements across different work vehicle applications.
Solution Approach 2:
The patent applies segmentation by making the planet-carrier assembly a separate, interchangeable component that can be easily swapped between different gearbox units. This modular approach allows manufacturers to produce standardized gearbox housings and gear sets, then configure different planet-carrier assemblies to meet specific application requirements, improving both manufacturing efficiency and design flexibility.
3Speed
If conventional gear ratios are used, then speed reduction is achieved, but component lifespan is reduced due to structural stress
Solution Approach 1:
The patent optimizes component lifespan through parameter changes in the gear tooth configuration. The high contact ratio achieved by the specific tooth count relationships ensures that load is distributed across at least two teeth simultaneously, reducing stress concentration on individual teeth. This load distribution minimizes fatigue and wear, extending the operational life of the gearbox components while maintaining the required speed reduction ratio for work vehicle applications.
Data Source
AI summary
A work vehicle reduction drive assembly includes a drive having a drive shaft mechanically linked to a movable work component through a planetary gear train is. The planetary gear train includes a ring gear having a tooth count of Tring, a sun gear having a tooth count of Tsun, and a planet-carrier assembly including a plurality of planet gears each having a tooth count of Tplanet. Tring, Tsun, and Tplanet are selected such that each planet gear in the plurality of planet gears contacts at least two teeth of the sun gear and at least two teeth of the ring gear in all rotational positions of the planetary gear train. The sum of Tring and Tsun yields a positive integer when divided by a first number from a set {3, 4, 5} and when divided by a second number from the set {3, 4, 5}.