Multi-stage Transmission with Shared Planetary Gear Elements
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Solution Overview
Problem
Existing multi-stage transmissions for vehicles increase the number of internal components and cost while aiming to improve fuel efficiency, making it essential to design a transmission structure that maximizes efficiency with a small number of components and a simple configuration.
Innovation Solution
The proposed multi-stage transmission employs a configuration of planetary gear sets and shifting elements that include an input shaft and an output shaft, with four planetary gear sets each having three rotation elements and seven shifting elements, allowing for a variable connection structure between the rotation elements to achieve a high number of shift stages with a reduced component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the number of shift stages is increased to improve fuel efficiency, then fuel efficiency is improved, but the number of internal components increases and structure becomes complex
Solution Approach 1:
The patent merges multiple planetary gear sets into a single integrated structure where sun gears, planet gears, and ring gears from different gear sets share common rotational elements. This allows multiple shift stages to be achieved without proportionally increasing the number of independent components, thereby improving fuel efficiency while controlling device complexity.
Solution Approach 2:
The patent designs planetary gear sets where rotation elements serve multiple functions across different gear sets. For example, the ring gear of one planetary gear set serves as the sun gear of another, allowing a single component to participate in multiple gear ratio formations, thus achieving more shift stages with fewer components.
2Use of energy by moving object
If the number of shift stages is increased to improve fuel efficiency, then fuel efficiency is improved, but the weight increases
Solution Approach 1:
The patent combines multiple planetary gear sets into a compact integrated structure where components are shared across gear sets. This merging reduces the total material required compared to separate gear sets, achieving multiple shift stages for improved fuel efficiency while minimizing weight increase.
Solution Approach 2:
The patent arranges planetary gear sets in a nested configuration where inner gear sets are positioned within or alongside outer gear sets. This nesting allows compact packaging of multiple gear stages, reducing overall transmission size and weight while maintaining the fuel efficiency benefits of multiple shift stages.
3Use of energy by moving object
If the number of shift stages is increased to improve fuel efficiency, then fuel efficiency is improved, but the cost increases
Solution Approach 1:
The patent merges multiple planetary gear sets into a unified structure with shared components, reducing the total part count compared to conventional multi-stage transmissions. This consolidation simplifies manufacturing processes and reduces assembly steps, thereby improving fuel efficiency through multiple shift stages while controlling production cost.
Solution Approach 2:
The patent designs rotation elements that serve multiple gear sets simultaneously, allowing a single component to fulfill multiple functional roles. This multi-functionality reduces the number of parts that need to be manufactured and assembled, achieving cost efficiency while providing the fuel efficiency benefits of multiple shift stages.
4Object-affected harmful factors
If the number of shift stages is increased to improve vehicle silence, then vehicle silence is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple planetary gear sets into an integrated structure that achieves multiple shift stages necessary for keeping the engine in low-RPM bands for silence. The merged structure reduces the number of independent component assemblies, thereby improving vehicle silence while minimizing the increase in structural complexity.
Data Source
AI summary
A multi-stage transmission for a vehicle, may include an input shaft and an output shaft; a first planetary gear set, a second planetary gear set, a third planetary gear set, and a fourth planetary gear set provided to transfer a torque between the input shaft and the output shaft and each including three rotation elements; and seven shifting elements connected to the rotation elements of the planetary gear sets.