Compact Five-Speed Planetary Transmission Design
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Solution Overview
Problem
Conventional planetary gear transmissions require a large installation footprint due to the need for multiple gear sets to achieve a wide range of speed ratios, often limiting the number of reverse speed ratios available.
Innovation Solution
A compact transmission system utilizing five planetary gear sets, four brakes, and two clutches to achieve five forward speeds and four reverse speeds, with specific brake and clutch configurations allowing selective actuation to optimize gear ratios and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gear sets are used to achieve a wide range of speed ratios, then the number of forward speeds increases, but the installation footprint increases
Solution Approach 1:
The patent merges five planetary gear sets into a single integrated transmission system where all gear sets share common components (input shaft, output shaft, carrier structures). This consolidation allows multiple speed ratios to be achieved within a compact footprint by selectively engaging different planetary sets through clutches and brakes, rather than requiring separate gear sets for each ratio.
Solution Approach 2:
The planetary gear sets are designed with multi-functionality where each set can serve multiple purposes: providing forward speeds, reverse speeds, and direct drive capabilities. The clutches and brakes are configured to selectively engage different planetary sets for different functions, maximizing the utility of each component and reducing the overall number of components needed.
2Adaptability or versatility
If more brakes and clutches are added to provide multiple reverse speeds, then the number of reverse speed ratios increases, but the device complexity increases
Solution Approach 1:
Each brake and clutch is designed to perform multiple functions across different operating modes. For example, the same clutch may be used to engage a planetary set for both forward and reverse operation, and the same brake may control different aspects of planetary set engagement. This multi-functionality reduces the total number of control components needed while still providing multiple reverse speed ratios.
Solution Approach 2:
The control system merges the functions of multiple brakes and clutches into a coordinated system where components work together to achieve multiple reverse speeds. Rather than having dedicated brakes and clutches for each reverse speed ratio, the system combines the control functions of fewer components to achieve the same result, reducing overall complexity.
Data Source
AI summary
A compact five-speed transmission planetary gear train includes a first, second, third, fourth and fifth planetary gear sets between an input and an output as well as first, second, third and fourth brakes and first and second clutches. The first, second, third and fourth brakes and first and second clutches are selectively actuatable to provide five different forward speeds and a plurality of different reverse speeds between the input and the output.