Power Shift Transmission Summation Unit for Wider Gear Ratio Spread
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power shift transmissions in agricultural machines require a high gear ratio spread with low mass inertia, necessitating multiple gears and components, which increases complexity, cost, and maintenance efforts.
Innovation Solution
A shift group design featuring individually shiftable transmission units with a 2:1 ratio in the second power path, combining planetary stages and branching couplings to reduce components and enhance gear configuration, allowing for a smaller number of gears and couplings while maintaining a high gear ratio spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of gears is increased to cover a high gear ratio spread, then the gear ratio spread is improved, but the device complexity increases
Solution Approach 1:
The patent combines two power paths (first power path with one transmission unit and second power path with two transmission units) within a single shift group to achieve multiple gear ratios. By merging the outputs of transmission units 50, 70, and 80 through the summation unit 40, the system achieves 5 forward gears and 2 reverse gears using only 3 transmission units, thereby reducing overall device complexity while maintaining high gear ratio spread
Solution Approach 2:
The summation unit 40 serves multiple functions: it combines power from different transmission units, enables both forward and reverse gear operation, and allows for variable gear ratios by selectively engaging different transmission units. This multi-functional component reduces the need for separate mechanisms for each function, thereby reducing device complexity while maintaining versatility
2Device complexity
If the number of transmission units is reduced, then the device complexity is reduced, but the number of achievable gears is limited
Solution Approach 1:
The patent employs dynamic engagement and disengagement of transmission units through individually controllable couplings (branching coupling 45 and transmission couplings 55, 65, 75, 85). By dynamically selecting which transmission units are active and how they are combined in the power paths, the system achieves 5 forward gears and 2 reverse gears using only 3 transmission units, thereby maximizing the number of achievable gears while minimizing device complexity
3Adaptability or versatility
If more components are used to achieve smooth transitions, then the gear ratio spread is improved, but the maintenance effort increases
Solution Approach 1:
The patent segments the transmission system into three independently controllable transmission units (50, 70, 80) with individually shiftable couplings. This segmentation allows for simplified maintenance and repair of individual units without affecting the entire system, reducing maintenance effort while enabling smooth transitions through selective engagement of different unit combinations
Data Source
AI summary
A shift group for a power shift transmission includes a summation unit having a planetary stage and a branching coupling assigned to the planetary stage. The summation unit is designed such that a mechanical power is transmitted from a first shaft to a second shaft. A first power path and a second power path are provided. In a first shifting state, the power is transmitted via the first or the second power path, and in a second shifting state, the power is transmitted via both the first and the second power paths. The shift group also includes individually shiftable transmission units each comprising a different transmission ratio, where a first transmission unit is disposed in the first power path and a second and a third transmission unit are disposed in the second power path.