Multi-Speed Transmission Using Segmented Planetary Gearsets
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Solution Overview
Problem
Current multiple speed transmissions face challenges in achieving a wide range of gear ratios with improved performance, cost efficiency, responsiveness, and packaging constraints, limiting their ability to effectively manage different speed requirements.
Innovation Solution
The design incorporates multiple planetary gearsets and torque-transmitting mechanisms that can be selectively engaged in various combinations to achieve at least eight forward and one reverse speed ratio, utilizing a combination of brakes and clutches to optimize gear shifting within a compact layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and torque-transmitting mechanisms are used to achieve a wide range of speed ratios, then the gear ratio range is improved, but the device complexity increases
Solution Approach 1:
The transmission system is divided into multiple planetary gearsets (first, second, third, and fourth planetary gearsets) with distinct functions. Each gearset handles specific gear ratio ranges, allowing the system to achieve a wide overall speed ratio range while managing complexity through functional segmentation. The gearsets are interconnected through a plurality of interconnecting members that selectively connect specific elements between gearsets.
Solution Approach 2:
The patent employs a nested arrangement where multiple planetary gearsets are interconnected in a compact configuration. The interconnecting members create a hierarchical structure where elements from different gearsets are linked, allowing the system to pack multiple gear reduction stages within a constrained space, achieving both wide ratio range and compact packaging.
2Adaptability or versatility
If five torque-transmitting mechanisms are selectively engaged in combinations to achieve eight forward and one reverse speed ratio, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
Each torque-transmitting mechanism is designed to perform multiple functions by being selectively engaged in different combinations. The same mechanism can contribute to different gear ratios depending on which other mechanisms are engaged, reducing the total number of mechanisms needed while achieving eight forward and one reverse speed ratio.
Solution Approach 2:
The system employs dynamic engagement and disengagement of torque-transmitting mechanisms to achieve different gear ratios. The selective combination of mechanisms allows the transmission to adapt its configuration in real-time, providing multiple speed ratios without requiring a fixed, complex mechanical structure for each ratio.
3Volume of moving object
If a compact layout is used to optimize packaging, then the volume is reduced, but the device complexity increases
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement to pack multiple planetary gearsets and interconnecting members in a compact volume. By arranging gearsets and connections in multiple dimensions rather than linear sequences, the system achieves compact packaging while maintaining the necessary mechanical clearances and connection paths.
Data Source
AI summary
A multiple speed transmission having an input member, an output member, a plurality of planetary gearsets, a plurality of interconnecting members and a plurality of torque-transmitting mechanisms. The plurality of planetary gear sets includes first, second and ring gears. The input member is continuously interconnected with at least one member of one of the plurality of planetary gear sets, and the output member is continuously interconnected with another member of one of the plurality of planetary gear sets. At least eight forward speeds and one reverse speed are achieved by the selective engagement of the five torque-transmitting mechanisms.