Multi-speed hub drive wheel with star compound gear train
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Solution Overview
Problem
Current electric vehicle drive systems, such as the Protean drive, face challenges with shock resistance, efficiency, limited speed options, and reliance on expensive rare earth magnets, which restrict their durability, cost-effectiveness, and adaptability to various driving conditions.
Innovation Solution
A multi-speed hub drive wheel system utilizing a rugged switched reluctance motor with a star compound gear train and a reconfigurable inverter, providing four operating regimes and a compact shifting mechanism for efficient acceleration and drivability, while eliminating the need for rare earth magnets and enhancing thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-speed electric motor is used, then the device complexity is reduced, but the adaptability to various driving conditions deteriorates
Solution Approach 1:
The patent implements a dynamic multi-speed drive system where the electric motor can switch between different operating speeds (first speed and second speed) based on driving conditions. The clutch mechanism enables dynamic reconfiguration of the gear train, allowing the system to adapt its transmission ratio and motor speed according to whether the vehicle is accelerating, cruising, or decelerating, thus resolving the contradiction between simplicity and adaptability.
2Ease of manufacture
If a single-speed motor is used, then the manufacturing cost is reduced, but the efficiency under varying operating conditions deteriorates
Solution Approach 1:
The patent changes the operating parameters of the electric motor by implementing multiple speed modes. The motor operates at a first higher speed during acceleration to provide high power output, and switches to a second lower speed during cruising to improve energy efficiency. This parameter change allows the system to optimize energy consumption across different driving conditions while maintaining reasonable manufacturing costs through a modular clutch-based architecture.
3Adaptability or versatility
If a multi-speed gear train is added, then the adaptability to driving conditions is improved, but the device complexity increases
Solution Approach 1:
The patent segments the drive system into distinct functional modules: the electric motor, the clutch mechanism, and the gear train. This segmentation allows each component to perform its specific function independently, making the overall multi-speed system more manageable and maintainable. The clutch acts as a separate switching mechanism that can engage or disengage different gear paths without requiring complete system redesign, thus reducing the effective complexity of the multi-speed architecture.
4Loss of energy
If a clutch mechanism is added for speed switching, then the efficiency is improved, but the reliability deteriorates due to additional moving parts
Solution Approach 1:
The clutch mechanism is designed to be actuated by the vehicle's existing braking system, allowing the braking force to automatically engage the clutch for speed switching without requiring additional actuators or complex control systems. This self-service approach leverages existing system resources to operate the clutch, reducing the number of additional moving parts and potential failure points while maintaining the energy efficiency benefits of multi-speed operation.
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 achieves improved shock resistance, efficiency, and adaptability, enabling enhanced acceleration, safety, and flexibility, with reduced costs and increased durability, allowing for broader application in various vehicle types and conditions.
Implementation Method 1
A multi-speed hub drive wheel system utilizing a rugged switched reluctance motor
Data Source
AI summary
A multi-speed hub drive wheel is provided which includes a wheel equipped with a hub; a star compound gear train having first and second stages; a motor disposed in the hub which drives the wheel by way of the star compound gear train; and a clutch which switches the hub drive wheel between a first mode of operation in which the motor engages the first stage of the star compound gear train, and a second mode of operation in which the motor engages the second stage of the star compound gear train.