Multi-speed Transmission with Nested 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 provide ten or more speeds effectively.
Innovation Solution
The design incorporates multiple planetary gearsets and torque-transmitting mechanisms that are selectively engageable in various combinations to establish at least ten forward and one reverse speed ratio, allowing for efficient shifting and gear changes through a complex interconnection of planetary gearsets and torque-transmitting mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and torque-transmitting mechanisms are used to achieve ten or more speed ratios, then the number of available speed ratios increases, but the device complexity increases
Solution Approach 1:
The transmission system is divided into four distinct planetary gearsets (first, second, third, and fourth), each with sun gears, ring gears, and carrier members. This segmentation allows independent control and engagement of different gear elements through six separate torque-transmitting mechanisms, enabling the system to achieve ten or more forward speed ratios and reverse speed ratios by selectively engaging specific combinations of these mechanisms.
Solution Approach 2:
The planetary gearsets are configured with multiple interconnections where components serve multiple functions. For example, the carrier member of the first planetary gearset is interconnected with both the sun gear and ring gear of other planetary gearsets, allowing a single component to participate in multiple gear ratio configurations. This multi-functionality enables the compact architecture to achieve high adaptability with ten or more speed ratios.
2Volume of moving object
If four planetary gearsets with multiple interconnections are used, then the packaging efficiency improves, but the device complexity increases
Solution Approach 1:
The four planetary gearsets are arranged in a nested configuration where components of one gearset are positioned within or adjacent to components of other gearsets. The interconnecting members link corresponding elements (sun gears, ring gears, carrier members) across different planetary gearsets, creating a compact nested structure that reduces overall transmission packaging volume while maintaining the complexity of interconnections necessary for achieving multiple speed ratios.
3Speed
If six torque-transmitting mechanisms are selectively engaged in combinations, then the responsiveness to gear changes improves, but the device complexity increases
Solution Approach 1:
The six torque-transmitting mechanisms are designed to be selectively engaged and disengaged through a control system that dynamically switches between different combinations of mechanisms to achieve desired gear ratios. This dynamic engagement allows rapid gear changes and responsive shifting between ten or more forward speed ratios and reverse speed ratios, while the distributed architecture of six separate mechanisms provides redundancy and flexibility in the control strategy.
Data Source
AI summary
The present disclosure provides 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. Each of the plurality of planetary gearsets includes a sun gear, a ring gear, and a carrier member with pinion 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 ten forward speeds and one reverse speed are achieved by the selective engagement of the plurality of torque-transmitting mechanisms.