Universal Wheel Gear Drive for Low Unsprung Mass and Stable Torque
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Solution Overview
Problem
In-wheel motor driving systems face issues with shortened motor lifespan, reduced driving comfort due to increased unsprung mass, and inefficiencies in power transfer, particularly during hill climbing and acceleration.
Innovation Solution
A universal wheel driving system featuring a sun gear, ring gear, gear train, and suspension mechanism that decelerates input power speed and increases torque, separates the power source from the wheel to mitigate harsh shocks and vibrations, reduces unsprung mass, and allows vertical wheel movement without a constant velocity joint, optimizing space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the power source is mounted inside the wheel (in-wheel motor system), then the space between wheels is utilized, but the motor lifespan is shortened due to harsh shocks and vibrations
Solution Approach 1:
The system divides the power source from the wheel assembly, mounting the motor in the vehicle body while transmitting power through a gear train to the wheel. This segmentation isolates the power source from harsh wheel conditions while maintaining compact space utilization.
Solution Approach 2:
A gear train acts as an intermediary mechanism between the power source and the wheel, enabling power transmission while physically separating the motor from the wheel's harsh environment. This intermediary protects the power source while achieving the desired power delivery.
2Power
If the power source is mounted inside the wheel, then direct power delivery is achieved, but the unsprung mass increases reducing driving comfort
Solution Approach 1:
The system segments the power source from the unsprung wheel mass, mounting the motor in the vehicle body. This reduces unsprung mass while maintaining effective power delivery through the gear train mechanism.
3Power
If a constant velocity joint is used to transfer power during vertical wheel movements, then power transfer is maintained, but the device complexity increases
Solution Approach 1:
Instead of allowing the wheel to move relative to the power source through complex joints, the system inverts the approach by allowing the gear train and carrier to move vertically with the wheel while the power source remains stationary. This simplifies the power transfer mechanism.
Solution Approach 2:
The gear train serves multiple functions: it transmits power from the sun gear to the ring gear while simultaneously accommodating vertical movements of the wheel. This multi-functionality eliminates the need for separate constant velocity joints.
4Adaptability or versatility
If the gear train allows relative motion between sun gear and ring gear rotation shafts, then vertical wheel movements are accommodated, but the manufacturing precision requirements increase
Solution Approach 1:
The system employs dynamic elements including a movable carrier and suspension portion that allow the gear train to adapt to vertical wheel movements. This dynamic design accommodates movement while maintaining manageable manufacturing precision requirements through controlled degrees of freedom.
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
The system enhances hill climbing and acceleration performance, extends power source lifespan, improves driving comfort, and ensures stable power transfer during vertical wheel movements, while minimizing space between wheels.
Implementation Method 1
a gear train engaged to the sun gear and the ring gear and configured to transfer the power between the sun gear and the ring gear while allowing relative motion between the rotation shafts of the sun gear and the ring gear
Implementation Method 2
a suspension portion provided to support the carrier against the sun gear so that the ring gear and the carrier move up and down with respect to the vehicle body
Data Source
AI summary
A universal wheel driving system includes a sun gear provided to receive power from a power source mounted in a vehicle body, a ring gear to which a wheel is concentrically connected, a gear train engaged to the sun gear and the ring gear and configured to transfer the power between the sun gear and the ring gear while allowing relative motion between the rotation shafts of the sun gear and the ring gear, a carrier supporting a final pinion of the gear train and gear-meshing with the ring gear so that a position of the rotation shaft of the final pinion remains unchanged with respect to a position of the rotation shaft of the ring gear, and a suspension portion provided to support the carrier against the sun gear so that the ring gear and the carrier move up and down with respect to the vehicle body.