Multi-speed Transmission with Four Planetary Gear Sets
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Solution Overview
Problem
Current multiple speed transmissions face challenges in achieving improved efficiency, responsiveness, smoothness, reduced size, and weight, while maintaining cost-effectiveness, particularly in achieving a compact design with a sufficient number of gear ratios.
Innovation Solution
A transmission design incorporating four planetary gear sets and six torque transmitting devices, including clutches and brakes, which are selectively engaged to establish multiple forward and reverse speed ratios through specific interconnections between the gear sets, allowing for compact and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gear sets are used to achieve multiple speed ratios, then the number of gear ratios increases, but the size and weight of the transmission increase
Solution Approach 1:
The patent combines four planetary gear sets into a single integrated transmission system where gear sets are coupled through shared members and interconnecting members. This merging approach allows multiple speed ratios to be achieved while consolidating components, thereby reducing overall weight compared to separate gear sets.
Solution Approach 2:
The transmission system uses six torque transmitting devices that can be selectively engaged in various combinations to provide multiple forward speed ratios and reverse speed ratios. This multi-functionality allows a single transmission design to achieve diverse gear ratios without proportionally increasing weight, as the same physical components serve multiple operational purposes.
2Adaptability or versatility
If multiple planetary gear sets are used to achieve multiple speed ratios, then the number of gear ratios increases, but the physical size of the transmission increases
Solution Approach 1:
The planetary gear sets are arranged in a nested configuration where gear sets share common members and interconnecting members. The first planetary gear set couples to the second through shared members, and the third couples to the fourth similarly, creating a compact nested structure that minimizes overall transmission size while maintaining multiple speed ratios.
Solution Approach 2:
The patent arranges planetary gear sets in a multi-dimensional layout with interconnecting members that link gear sets across different spatial dimensions. This dimensional arrangement allows efficient space utilization, enabling multiple gear ratios to be achieved within a compact volume by optimizing the spatial relationship between components.
3Adaptability or versatility
If six torque transmitting devices are used to achieve nine or ten forward speed ratios, then the number of speed ratios increases, but the device complexity increases
Solution Approach 1:
The transmission system employs dynamic engagement and disengagement of six torque transmitting devices through combinations of at least three devices. This dynamic configuration allows the system to switch between different gear ratios by selectively activating specific device combinations, providing adaptability without requiring a permanently complex mechanical structure for each individual ratio.
Data Source
AI summary
A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes. The torque transmitting devices are each selectively engageable in combinations of at least three to establish a plurality of forward speed ratios and at least one reverse speed ratio between the input member and the output member.