Shiftable Wheel End Reduction With Planetary Torque-Speed Switching
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Solution Overview
Problem
Current powertrain technologies in wheeled vehicles lack the ability to efficiently switch between torque and speed modes, limiting their adaptability and efficiency in transferring mechanical power from engines or motors to wheels.
Innovation Solution
A shiftable wheel end reduction system utilizing a planetary gear set with a first and second clutch mechanism, allowing the system to switch between a high-torque, low-speed mode and a low-torque, high-speed mode by adjusting the engagement of the outer ring gear with the axle body and gear carrier, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed wheel end reduction is used, then the structure is simple, but the adaptability to different torque and speed requirements is poor
Solution Approach 1:
The wheel end reduction employs a shiftable planetary gear set that can dynamically change its reduction ratio between different operating modes. The gear set includes a sun gear, planet gears, a gear carrier, and a ring gear, with clutch mechanisms enabling selective engagement to achieve different torque and speed characteristics at the wheel, thereby providing adaptability without requiring multiple fixed reduction units.
Solution Approach 2:
The single wheel end reduction unit is designed to perform multiple functions by incorporating a shiftable planetary gear set with different operating modes. This allows one component to replace what would traditionally require multiple fixed reduction units, providing both direct drive capability and reduced gear ratio capability within a single integrated assembly.
2Adaptability or versatility
If a shiftable wheel end reduction is used, then the operational flexibility is enhanced, but the device complexity increases
Solution Approach 1:
The shiftable planetary gear set enables dynamic adjustment of the reduction ratio by engaging different clutch mechanisms. The system can switch between operating modes with different reduction ratios based on real-time vehicle requirements, providing operational flexibility while keeping the mechanical structure relatively compact and integrated.
3Force
If torque is increased by a factor of 2 to 5 through gear reduction, then the wheel torque is enhanced, but the wheel speed is reduced
Solution Approach 1:
The planetary gear set provides different reduction ratios in different operating modes, allowing the system to select an appropriate balance between torque multiplication and speed reduction based on driving conditions. This dynamic adjustment capability resolves the fixed trade-off between torque and speed by enabling the system to optimize for either parameter as needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient power transfer by increasing torque by a factor of 2 to 5 in one mode and maintaining torque in another, enhancing the vehicle's operational flexibility and reducing component size and cost within the powertrain.
Implementation Method 1
The shiftable wheel end reduction may include a planetary gear set including an outer ring gear, a plurality of planet gears, a gear carrier, and a sun gear
Implementation Method 2
The gear carrier may be rotatably mounted on the axle body by a roller bearing
Data Source
AI summary
A shiftable wheel end reduction may be mechanically coupled to a driven axle shaft and to a driven wheel of a wheeled vehicle. The shiftable wheel end reduction may be switched between a first operating mode, in which torque carried by the driven axle shaft is increased and transferred to the driven wheel by the shiftable wheel end reduction, and a second operating mode, in which torque carried by the driven axle shaft is maintained and transferred to the driven wheel by the shiftable wheel end reduction.