EV Drive Unit Locking Mechanism for Incline Parking Stability
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Solution Overview
Problem
Electric vehicles equipped with electric motors and torque converters face the challenge of preventing unintended movement when parked on inclines, as existing systems lack effective mechanisms to lock the drivetrain in a state that prevents rotation.
Innovation Solution
A drive unit configuration that includes an electric motor, torque converter, power transmission unit, first and second shafts, and switching mechanisms, allowing the system to switch between forward drive, neutral, and locking states to prevent torque transmission and rotation when parked, utilizing a control unit to adjust motor characteristics for high-speed or low-speed modes and incorporating a clutch for torque interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a torque converter is provided to amplify torque from the electric motor, then the driving performance is improved, but the vehicle may move unintentionally when parked on inclines
Solution Approach 1:
A switching mechanism is introduced as an intermediary component between the torque converter and the drive wheels. This switching mechanism includes a locking state that can prevent torque transmission to the drive wheels, thereby stopping the vehicle when parked on inclines while maintaining the torque amplification capability of the torque converter during normal operation
2Reliability
If a switching mechanism is added to prevent vehicle movement when parked, then the vehicle stability is improved, but the device complexity increases
Solution Approach 1:
The switching mechanism is designed to perform multiple functions: it can switch between a forward drive state for normal operation, a neutral state for torque interruption, and a locking state for preventing vehicle movement when parked. By consolidating these functions into a single mechanism, the increase in device complexity is minimized while achieving reliable vehicle stability control
3Speed
If the first forward drive gear train has a smaller reduction ratio for high-speed operation, then the speed performance is improved, but the torque output at low speed is reduced
Solution Approach 1:
The system employs two different forward drive gear trains with different reduction ratios that can be dynamically selected based on operating conditions. The first forward drive gear train with a smaller reduction ratio is used for high-speed operation to maintain speed performance, while the second forward drive gear train with a larger reduction ratio is used for low-speed operation to maximize torque output. The switching mechanism enables dynamic transition between these gear trains
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
Effectively prevents the vehicle from moving while parked by ensuring the drivetrain is locked in a state that prevents rotation, enhancing safety and security by maintaining vehicle stability on slopes.
Implementation Method 1
a torque converter configured to amplify torque in a first rotation direction output from the electric motor
Data Source
AI summary
A drive unit includes an electric motor, a torque converter, a power transmission unit, a first shaft, a second shaft, and a first switching mechanism. The torque converter amplifies torque from the electric motor in a first rotation direction. The power transmission unit includes first and second forward drive gear trains. The first shaft transmits torque from the electric motor to the torque converter. The second shaft transmits torque from the torque converter to the second forward drive gear train. The first switching mechanism transmits torque from the first shaft to the first forward drive gear train in a first forward drive state. The first switching mechanism does not transmit torque from the first shaft to the first forward drive gear train in a first neutral state. The first switching mechanism is configured not to allow the first forward drive gear train to rotate in a locking state.