Planetary EV Drivetrain with Claw Couplings for Seamless Mode Shifts
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Solution Overview
Problem
Existing electric drive trains for motor vehicles face challenges in achieving efficient power transmission and drivability, particularly in switching between operating modes without traction interruption.
Innovation Solution
An electric drive train design incorporating a planetary gearbox with unsymmetrical transmission stages and form-fitting switching elements, such as a claw coupling, allows for power shift capability, enabling seamless transitions between driving modes while minimizing energy loss and maintaining traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional switching elements are used in electric drive trains, then mode transitions can be achieved, but traction interruption occurs during switching
Solution Approach 1:
The patent introduces a planetary gearbox as an intermediary mechanism between the electric motor and the driving wheels. The planetary gearbox with multiple shafts (first through fifth shafts) and gear elements enables torque to be transmitted through alternative paths during mode transitions, preventing traction interruption. The unsymmetrical transmission stages allow seamless switching between operating modes while maintaining continuous torque delivery to the wheels.
Solution Approach 2:
The patent employs dynamic switching elements (claw couplings) that can change their coupling state during operation. The first and second claw couplings enable the system to dynamically reconfigure torque transmission paths by engaging or disengaging connections between different shafts and the common planetary carrier, allowing smooth mode transitions without losing traction.
2Loss of energy
If power transmission efficiency is improved through direct coupling, then energy loss is reduced, but switching between operating modes becomes difficult
Solution Approach 1:
The patent segments the power transmission system into multiple independent shafts (first through fifth shafts) and gear elements within the planetary gearbox. This segmentation allows the system to maintain efficient direct coupling for power transmission while enabling selective engagement of different transmission paths for mode switching. The modular structure with multiple shafts permits energy-efficient operation in each mode while providing flexibility for transitions.
Solution Approach 2:
The planetary gearbox serves multiple functions simultaneously: it transmits torque efficiently through direct coupling in each operating mode, enables switching between different operating modes, and provides mechanical advantage through the planetary gear mechanism. The common planetary carrier and multiple shafts allow the single gearbox structure to fulfill both efficiency and adaptability requirements.
3Adaptability or versatility
If complex switching mechanisms are introduced to enable mode transitions, then operating mode versatility is improved, but device complexity increases
Solution Approach 1:
The patent merges the switching mechanism directly into the planetary gearbox structure itself, rather than adding separate switching components. The claw couplings are integrated with the shafts and planetary carrier, allowing mode transitions to be achieved through the gearbox's inherent mechanical structure. This integration reduces overall device complexity while maintaining multi-mode capability.
Solution Approach 2:
The planetary gearbox structure serves its own switching function through the arrangement of its shafts and gear elements. The unsymmetrical transmission stages and the configuration of the common planetary carrier with multiple shafts enable the gearbox to automatically facilitate mode transitions through its mechanical design, reducing the need for external complex switching mechanisms.
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 design achieves particularly good driving dynamics and comfort by allowing mode transitions without traction interruption, with low energy loss and efficient torque distribution across vehicle wheels.
Implementation Method 1
The planetary gearbox has a first shaft, a second shaft, a third shaft, a fourth shaft, and a fifth shaft... The planetary gearbox has at least or exactly six gear elements... a first of the gear elements is a first sun gear, for example, a second of the gear elements is a first planetary carrier
Data Source
AI summary
An electric drive train for a motor vehicle having first and second electric engines and a planetary gearbox which has a first shaft, a second shaft, a third shaft, a fourth shaft and a fifth shaft, and first and second vehicle wheels. With regard to a torque flow originating from the electric engines running to the vehicle wheels, the electric engines are arranged upstream of the planetary gearbox, which is arranged upstream of the vehicle wheels in the torque flow. A first switching element is provided to couple the second rotor to the first shaft.