Planetary Multi-Speed Transmission With Selective Torque Paths
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Solution Overview
Problem
Current multiple speed transmissions face challenges in achieving a high number of gear ratios with improved performance, cost efficiency, responsiveness, and packaging, particularly in military tracked vehicles requiring high ratio coverage and low transmission losses across varying speeds.
Innovation Solution
The design incorporates multiple planetary gearsets and torque-transmitting mechanisms that can be selectively engaged in various combinations to achieve at least ten forward and one reverse speed ratio, allowing for adaptable packaging on single or parallel axes, utilizing a combination of planetary gearsets and torque-transmitting mechanisms to optimize gear shifting and transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple planetary gearsets and torque-transmitting mechanisms are used to achieve high number of gear ratios, then the number of speed ratios is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple planetary gearsets (first, second, third, and fourth planetary gearsets) with multiple torque-transmitting mechanisms into a single integrated transmission system. This merging approach allows the system to achieve at least ten forward speed ratios and one reverse speed ratio through coordinated operation of the combined components, rather than using separate transmission systems for different ratios.
Solution Approach 2:
The torque-transmitting mechanisms are designed to perform multiple functions by selectively interconnecting different members of the planetary gearsets. The same mechanisms can engage different gearset members to achieve various speed ratios, making the transmission system multi-functional and capable of adapting to different operating conditions without requiring separate dedicated mechanisms for each ratio.
2Adaptability or versatility
If multiple torque-transmitting mechanisms are selectively engaged to achieve multiple speed ratios, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The transmission system employs dynamically selectable torque-transmitting mechanisms that can be engaged or disengaged based on the required speed ratio. This dynamic configuration allows the system to adapt to different operating conditions (low speed/high torque vs. high speed/low torque) by selectively activating the appropriate mechanisms, rather than maintaining a fixed complex structure for all conditions.
Solution Approach 2:
The transmission system is segmented into multiple independent planetary gearsets (first, second, third, fourth) that can operate semi-independently. Each gearset can be engaged or disengaged through the torque-transmitting mechanisms, allowing the system to segment the overall transmission function into manageable modules that can be selectively activated based on performance requirements.
3Force
If planetary gearsets are used to achieve high ratio coverage, then the tractive effort at lower speeds is improved, but the transmission losses at higher speeds increase
Solution Approach 1:
The system changes operational parameters by selecting different planetary gearsets and torque-transmitting mechanisms based on the required speed ratio. At lower speeds, the system engages mechanisms that provide higher torque multiplication for maximum tractive effort. At higher speeds, it switches to mechanisms with lower inherent losses, thereby adapting the transmission characteristics to minimize energy losses across the operating range.
Solution Approach 2:
The transmission system dynamically switches between different gear pathways using the selectively engageable torque-transmitting mechanisms. This dynamic switching allows the system to optimize for tractive effort when high force is needed (lower speeds) and minimize transmission losses when high speed operation is required, rather than being locked into a single gear configuration.
Data Source
AI summary
A multiple speed transmission includes an input member, an output member, first, second, third and fourth planetary gearsets each having first, second and third members, and a plurality of interconnecting members each connected between at least one of the first, second, third, and fourth planetary gearsets and at least another of the first, second, third, and fourth planetary gearsets. The transmission includes a plurality of torque-transmitting mechanisms between the input and output members, wherein the torque transmitting mechanisms are selectively engageable in combinations of at least four to establish at least ten forward speed ratios between the input member and the output member.