Planetary Transmission Layout for More Gear Ratios
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current multi-speed transmissions face limitations in achieving a sufficient number of forward and reverse speed ratios using planetary gearsets and selective couplers, as they often require complex configurations and may not efficiently provide the desired range of gear ratios.
Innovation Solution
The use of multiple planetary gearsets and selective couplers, including clutches and brakes, allows for the interconnection of components to achieve at least nine forward speed ratios and one reverse speed ratio by varying the engagement of selective couplers, enabling flexible torque transmission and gear ratio adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and selective couplers are used to achieve more forward and reverse speed ratios, then the transmission capability and adaptability are improved, but the device complexity increases
Solution Approach 1:
The transmission system is divided into multiple independent planetary gearsets (first, second, third, and fourth planetary gearsets) that can be selectively engaged through individual selective couplers. Each planetary gearset can provide specific gear ratios, and by segmenting the transmission into these modular units, the system achieves multiple forward and reverse speed ratios without requiring a completely complex redesign of the entire transmission system.
Solution Approach 2:
The selective couplers serve multiple functions: they can engage different planetary gearsets, provide forward gear ratios, provide reverse gear ratios, and enable smooth transitions between different transmission modes. This multi-functionality allows the transmission system to achieve high adaptability with a relatively compact and manageable structure, as each coupler handles multiple transmission tasks rather than requiring dedicated components for each function.
2Adaptability or versatility
If selective couplers are used to provide multiple forward and reverse speed ratios, then the adaptability to different operational conditions is improved, but the device complexity increases
Solution Approach 1:
The selective couplers enable dynamic engagement and disengagement of different planetary gearsets based on operational requirements. The transmission system can adaptively switch between different gear ratios and transmission modes (forward, reverse, neutral) by dynamically controlling which selective couplers are engaged, allowing the system to optimize performance for different driving conditions without requiring a fixed complex structure.
3Productivity
If multiple planetary gearsets are interconnected to achieve a wide range of gear ratios, then the productivity and efficiency are improved, but the device complexity increases
Solution Approach 1:
Multiple planetary gearsets are merged into a single integrated transmission system where the gearsets are interconnected through selective couplers and interconnectors. This merging allows the system to achieve a wide range of gear ratios by combining the rotational outputs of different planetary gearsets, improving productivity and efficiency by enabling smooth power transmission across multiple speed ratios without requiring separate transmission systems for each gear ratio.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multi-speed transmission (300) including a plurality of planetary gearsets (308, 310, 312, 314) and a plurality of selective couplers (362, 364, 366, 368, 370, 372) is disclosed. The plurality of planetary gearsets (308, 310, 312, 314) includes a first planetary gearset (308), a second planetary gearset (310), a third planetary gearset (312), and a fourth planetary gearset (314). The plurality of selective couplers (362, 364, 366, 368, 370, 372) includes six selective couplers which may include four clutches (366, 368, 370, 372) and two brakes (362, 364).