Hybrid Drive Gearbox Layout for Compact Multi-Gear Torque Transfer
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Solution Overview
Problem
Existing hybrid drive systems face challenges in achieving a compact design and efficient operation, particularly in terms of installation space, drivability, and energy efficiency.
Innovation Solution
The hybrid drive system integrates an electric motor with a rotor coupled to the input shaft of a gearbox, bypassing the planetary gear, and incorporates a multi-gear configuration with shift elements to optimize torque transmission and reduce installation space, weight, and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electric motor is integrated with the planetary gear unit in a conventional hybrid drive system, then the installation space is reduced, but the structural complexity and difficulty of torque transmission increase
Solution Approach 1:
The hybrid drive system separates the electric motor from the planetary gear unit, allowing the electric motor to be coupled to the input shaft independently. This segmentation simplifies the torque transmission path and reduces structural complexity while maintaining compact installation through independent positioning of components.
Solution Approach 2:
The input shaft serves multiple functions: it transmits torque from the internal combustion engine and simultaneously serves as the coupling point for the electric motor. This multi-functionality reduces the need for additional transmission paths and simplifies the overall structure.
2Ease of operation
If a multi-gear configuration is added to improve drivability, then the drivability and energy efficiency are enhanced, but the device complexity and installation space increase
Solution Approach 1:
The cylindrical gear unit and planetary gear unit are merged into a single integrated gearbox structure. The cylindrical gears provide multiple gear ratios for improved drivability, while the planetary gear unit handles torque multiplication, combining both functions in one compact unit to avoid the complexity of separate gear systems.
Solution Approach 2:
The patent utilizes axial positioning of different gear units along the input shaft to create a compact multi-gear configuration. By arranging gears in the axial dimension rather than requiring radial expansion, the system achieves multiple gear ratios without significantly increasing the overall footprint.
3Loss of energy
If the electric motor is coupled to bypass the planetary gear, then the torque transmission efficiency is improved, but the adaptability to different operating conditions is reduced
Solution Approach 1:
The system dynamically switches between different torque transmission paths based on operating conditions. The electric motor can couple directly to the input shaft for efficient torque transmission during steady-state operation, while the planetary gear unit remains available for high-torque situations, providing adaptability through dynamic engagement/disengagement of different transmission paths.
Data Source
AI summary
A hybrid drive system for a motor vehicle includes an internal combustion engine having a crankshaft, an electric motor having a rotor, and a gearbox having a cylindrical gear unit with an input shaft coupled or coupleable to the crankshaft for conjoint rotation and an output shaft arranged parallel to the input shaft. The gearbox includes a planetary gear with a first element, a second element, and a third element. The system also includes a differential gearing. The rotor of the electric motor is coupled to the input shaft in such a way that torques provided by the electric motor via the rotor can be introduced into the gearbox via the input shaft. The input shaft is connected to the first element for conjoint rotation. The second element is connected to a first fixed gear for conjoint rotation.