Multi-Speed Range Transmission with Reduced Clutch Changes
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Solution Overview
Problem
Current powershift transmissions in off-highway vehicles face challenges with increased complexity and reduced efficiency due to the need for a large number of speeds, requiring multiple clutch changes and large gear ratio differences, which affect shiftability and operator comfort.
Innovation Solution
A transmission system with an input section and a range section, where the range section maintains at least two clutches in an engaged state while transitioning a maximum of one clutch during sequential shifts, providing multiple speed ranges with reduced clutch changes and smaller gear ratio changes, enhancing shiftability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large number of speeds are required to accommodate increased power and speed range, then the speed range capability is improved, but the device complexity increases due to multiple clutch changes and large gear ratio differences
Solution Approach 1:
The transmission is divided into an input section and a range section, each with dedicated clutches. The input section clutches handle input speed selection while the range section clutches handle range transitions. This segmentation allows independent optimization of each section's clutching strategy, reducing overall complexity despite providing many speeds.
Solution Approach 2:
The patent implements dynamic clutch control where at least two range clutches remain engaged during sequential shifts, and maximum one clutch transition occurs. This dynamic approach adapts the clutch engagement strategy based on the shift sequence, maintaining smooth operation while reducing complexity compared to traditional multi-clutch swapping methods.
2Adaptability or versatility
If multiple clutch changes are implemented to provide large number of speeds, then the speed range is improved, but the shiftability deteriorates due to operator comfort issues
Solution Approach 1:
The system dynamically maintains at least two range clutches in the engaged state during sequential shifts, limiting transitions to maximum one clutch change. This dynamic clutch management strategy ensures smooth, comfortable shifts while providing access to multiple speeds, directly addressing the shiftability problem.
3Adaptability or versatility
If traditional powershift transmission design is used to provide multiple speeds, then the speed capability is improved, but the efficiency deteriorates due to large gear ratio differences
Solution Approach 1:
By segmenting the transmission into input and range sections with dedicated clutch systems, the patent enables optimized gear ratio progression within each section. This segmentation allows for smaller, more efficient gear ratio steps while maintaining the overall speed capability, reducing energy loss during transitions.
Data Source
AI summary
A transmission system configured to transfer power from a power source to a load is provided. The transmission system includes an input section coupled to the power source and a range section coupled to the load. The input section includes a plurality of input clutches configured to selectively transition between engaged and disengaged states to provide one or more input speeds. The range section includes a plurality of range clutches configured to be selectively transition between engaged and disengaged states to provide one or more speed ranges. When the range section is commanded to sequentially shift between two of the one or more speed ranges, the range section is configured to maintain at least two of the plurality of range clutches in the engaged state and transition a maximum of one of the plurality of range clutches from the disengaged state to the engaged state.