Multi-speed Transmission Using Planetary Gear Sets
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Solution Overview
Problem
Conventional multi-speed transmissions are not cost-effective or compact enough to meet the demands of lighter and more compact vehicle designs, necessitating a new configuration that achieves multiple gear ratios efficiently.
Innovation Solution
A multi-speed transmission design incorporating multiple planetary gear sets and selectively engageable torque-transmitting mechanisms, which interconnect various gear members to establish at least eight forward and one reverse speed ratio, utilizing a combination of sun gears, carrier members, and ring gears with interconnecting members and torque-transmitting mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional friction clutches and planetary gear arrangements are used to achieve multiple gear ratios, then the transmission can provide multiple speed ratios, but the transmission size and weight increase, making it not compact enough for lighter and more compact vehicle designs
Solution Approach 1:
The patent combines multiple planetary gear sets (first, second, third planetary gear sets with sun gears, carrier members, and ring gears) into a single integrated transmission assembly, where gear members are shared across multiple gear ratios. This merging approach allows achieving multiple speed ratios without proportionally increasing transmission size, as the same physical components serve multiple gear ratio functions through selective engagement of torque-transmitting mechanisms.
Solution Approach 2:
The transmission design makes gear members universal by having them participate in multiple gear ratio configurations. For example, the sun gear, carrier member, and ring gear of each planetary gear set can be interconnected through different torque-transmitting mechanisms to achieve different forward and reverse speed ratios, allowing each component to serve multiple functions across different operating conditions.
2Adaptability or versatility
If conventional friction clutches and planetary gear arrangements are used to achieve multiple gear ratios, then the transmission can provide multiple speed ratios, but the manufacturing cost increases, making it not cost-effective
Solution Approach 1:
The patent merges multiple planetary gear sets into a compact assembly where components are shared across different gear ratio pathways. This reduces the total number of discrete components needed compared to using separate gear trains for each ratio, thereby lowering manufacturing complexity and cost while still achieving multiple forward and reverse speed ratios through selective engagement of torque-transmitting mechanisms.
Solution Approach 2:
By designing gear members to be universal and multi-functional, the patent reduces the overall component count. Each planetary gear set's sun gear, carrier member, and ring gear can be engaged with different torque-transmitting mechanisms to produce multiple gear ratios, eliminating the need for dedicated components for each ratio and thus reducing manufacturing costs.
3Adaptability or versatility
If multiple planetary gear sets and torque-transmitting mechanisms are used to achieve at least eight forward and one reverse speed ratio, then the gear ratio versatility improves, but the device complexity increases
Solution Approach 1:
The patent segments the transmission into three distinct planetary gear sets, each with its own sun gear, carrier member, and ring gear. This segmentation allows independent control and engagement of each gear set through separate torque-transmitting mechanisms, making it easier to manage complexity by dividing the overall system into modular, controllable units that can be engaged in different combinations to achieve the desired speed ratios.
Solution Approach 2:
The transmission employs selectively engageable torque-transmitting mechanisms that can dynamically connect or disconnect different gear members (sun gears, carrier members, ring gears) of the planetary gear sets. This dynamic engagement capability allows the system to adapt its internal configuration based on the required gear ratio, achieving high versatility (eight forward and one reverse speed ratio) while managing complexity through controlled, on-demand reconfiguration rather than fixed complex linkages.
Data Source
AI summary
A transmission is disclosed having an input member, an output member, a plurality of planetary gear sets, a plurality of interconnecting members and a plurality of torque-transmitting mechanisms. The plurality of planetary gear sets has first, second and third members. The input member is continuously interconnected with a member of the planetary gear sets. The output member is continuously interconnected with another member of the planetary gear sets. At least eight forward speeds and one reverse speed are produced by the selective engagement of the five torque-transmitting mechanisms.