Planetary Transmission Coupler Layout for Wide Speed Ratios
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Solution Overview
Problem
Existing multi-speed transmissions face challenges in achieving a wide range of forward and reverse speed ratios efficiently using conventional planetary gearsets and selective couplers.
Innovation Solution
A multi-speed transmission design incorporating multiple planetary gearsets and selective couplers, including interconnectors and a retarder, with a fluid control system to manage fluid in the retarder housing, allowing for a variety of speed ratios through engagement of different couplers and brakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and selective couplers are used to achieve a wide range of speed ratios, then the versatility and performance of the transmission are improved, but the device complexity and cost increase
Solution Approach 1:
The transmission system is divided into multiple independent planetary gearsets (first, second, third planetary gearsets) housed in separate housings. Each planetary gearset can be independently configured and connected through selective couplers, allowing the system to achieve multiple speed ratios by engaging different combinations of gearsets rather than requiring a single complex geartrain
Solution Approach 2:
Selective couplers are used to dynamically connect and disconnect different planetary gearsets based on the desired speed ratio. This allows the transmission to adapt its configuration in real-time, engaging only the necessary gearsets for each operating condition, thereby achieving versatility without permanently fixed complex connections
2Productivity
If multiple planetary gearsets and selective couplers are used to achieve a wide range of speed ratios, then the performance is enhanced, but the system becomes cumbersome
Solution Approach 1:
By segmenting the transmission into separate planetary gearset modules housed in individual housings, the system achieves high performance through multiple gear ratios while reducing overall complexity. Each module can be optimized independently and connected only when needed, eliminating the need for a single cumbersome integrated geartrain
Solution Approach 2:
The planetary gearsets are configured to serve multiple functions - each can provide different speed ratios when engaged with different selective couplers. This multi-functionality allows the system to achieve a wide range of speed ratios using the same physical components in different configurations, reducing the need for additional specialized components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enables a broader range of speed ratios with improved efficiency and flexibility, enhancing the performance of vehicles by adapting to various driving conditions.
Implementation Method 1
a retarder including a retarder housing, a rotor fixedly coupled to the second gearset component of the third planetary gearset, the first gearset component of the fourth planetary gearset, and the first gearset component of the fifth planetary gearset and positioned in the retarder housing, and a stator positioned in the retarder housing and fixedly coupled to the at least one stationary member
Data Source
AI summary
A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers is disclosed. The multi-speed transmission may include a retarder including a retarder housing, a rotor positioned in the retarder housing and fixedly coupled to a portion of the plurality of planetary gearsets, and a stator positioned in the retarder housing and fixedly coupled to at least one stationary member.