Hybrid Axle Drive Torque Vectoring Planetary Gearset
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Solution Overview
Problem
Existing hybrid axle drives lack efficient torque vectoring capability, which is essential for optimizing power distribution between wheels during cornering and varying traction conditions, leading to suboptimal vehicle performance and energy efficiency.
Innovation Solution
The integration of torque vectoring gearing, comprising a stepped planetary gearset with friction elements, allows for selective power transmission between the electric machine and half-shafts, enabling dynamic adjustment of torque distribution based on speed differences between half-shafts to enhance power flow and reduce energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional differential is used to distribute power to wheels, then the structure is simple and reliable, but torque vectoring capability is lacking, resulting in suboptimal vehicle performance during cornering and varying traction conditions
Solution Approach 1:
The patent combines the final drive gearing and torque vectoring gearing into a single integrated planetary gearset structure. The planetary gears simultaneously perform both final drive reduction and torque vectoring functions, eliminating the need for separate differentials and torque vectoring mechanisms. This merging approach adds torque vectoring capability while minimizing structural complexity increase.
Solution Approach 2:
The planetary gearset is designed to perform multiple functions: it provides final drive reduction, acts as a differential allowing speed differences between wheels, and enables active torque vectoring through friction element engagement. This multi-functionality allows a single component to replace what would traditionally require multiple separate systems.
2Ease of operation
If friction elements are engaged to transmit power through torque vectoring gearing, then precise torque distribution is achieved, but power dissipation increases due to friction
Solution Approach 1:
The friction elements are designed to be selectively engaged and disengaged based on real-time operating conditions such as wheel speed differences and traction requirements. The system dynamically adjusts torque vectoring activation, engaging friction elements only when torque redistribution is needed rather than continuously, thereby minimizing energy loss while maintaining control capability.
3Manufacturing precision
If multiple friction elements are used in the torque vectoring gearing, then torque distribution precision is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The planetary gearset is designed with nested components where friction elements are integrated within the existing gear structure rather than added as separate external components. The multi-plate brakes are positioned within the planetary gear assembly, utilizing the same spatial envelope and mounting structures, which reduces manufacturing complexity despite the presence of multiple friction elements.
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
This solution enables precise control of torque distribution between wheels, improving vehicle stability and efficiency during turns by minimizing power dissipation through selective engagement of friction elements, thereby enhancing overall vehicle performance and energy management.
Implementation Method 1
The torque vectoring gearing transmits power from the rotor to the first half-shaft in response to application of a first friction element while the first half-shaft is rotating faster than the differential input.
Data Source
AI summary
An electric axle drive utilizes an electric motor to propel both half-shafts via final drive gearing and a differential. Torque vectoring gearing alters the torque distribution by transmitting power from one of the half shafts to the motor or from the motor to the half-shaft in response to engagement of brakes. Both the final drive gearing and the torque vectoring gearing are implemented using stepped planetary gear sets. The final drive gearing and differential are located on one end of the electric motor. The torque vectoring gearing is located on the opposite end of the electric motor.