Nested Planetary Gearing for Compact Axial Length
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Solution Overview
Problem
Conventional multistage planetary gearing devices are bulky and heavy due to the stringing together of multiple gear trains, resulting in a large overall length and unnecessary small stage increments, which wastes space and weight in motor vehicles.
Innovation Solution
A compact planetary gearing device is designed with three or more planetary gear trains, where the first gear train is constructed as a plus-type gear train, and the second and third gear trains are arranged to minimize axial length, using a selective connection of elements and torque transmission devices to achieve six forward gears and one reverse gear, with torque transmission devices strategically placed for efficient power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gear trains are strung together to achieve high transmission ratios, then the number of gear ratios increases, but the overall length and weight of the gearing device increase significantly
Solution Approach 1:
The patent applies nesting by placing the first planetary gear train inside the second planetary gear train, with the sun gear of the first train positioned within the ring gear of the second train. This nested configuration allows multiple gear trains to occupy the same axial space, achieving high transmission ratios without increasing overall length proportionally to the number of gear stages.
Solution Approach 2:
The patent transitions from a linear stringing arrangement (one-dimensional extension) to a nested concentric arrangement (utilizing radial and axial dimensions simultaneously). By organizing gear trains in concentric layers rather than sequential segments, the design achieves multiple transmission stages within a compact axial footprint.
2Adaptability or versatility
If multiple planetary gear trains are strung together to achieve high transmission ratios, then the number of gear ratios increases, but the weight of the gearing device increases
Solution Approach 1:
The nested configuration allows multiple gear trains to share common structural elements and mounting spaces, reducing the total material required compared to separate, stringed-together gear trains. The concentric arrangement enables more efficient use of materials by eliminating redundant support structures.
Solution Approach 2:
The patent merges multiple gear trains into a single integrated unit where components are combined and shared across different transmission stages. This consolidation reduces the total weight by eliminating duplicate elements and creating a unified structural framework that supports multiple gear ratios.
3Length of stationary object
If planetary gear trains are arranged to minimize axial length through nesting, then the overall length decreases, but the device complexity increases
Solution Approach 1:
The patent segments the gearing device into distinct functional modules (first planetary gear train, second planetary gear train, torque transmission devices) that can be independently designed and assembled. This modular segmentation manages complexity by organizing the nested structure into manageable units with clear functional boundaries.
Solution Approach 2:
The patent employs universal elements such as the common input shaft and output shaft that serve multiple gear trains simultaneously. The torque transmission devices are designed to universally control multiple planetary gear trains, reducing the number of separate control mechanisms needed and managing system complexity.
Data Source
AI summary
A planetary gearing device includes a gearing input shaft, a gearing output shaft, a gearing housing, and at least a first, second and third planetary gear train, each having a sun gear, a ring gear and at least one planet gear. The planetary gear trains are centrally arranged with respect to a gearing axis and can be mutually, particularly selectively, connected with torque transmission devices. The first planetary gear train are arranged radially within the second planetary gear train. An individual sectional plane orthogonal with respect to the gearing axis intersects the first and the second planetary gear train, the first and the third planetary gear train being axially spaced from one another along this gearing axis. The first planetary gear train has at least a second planet gear.