Hybrid Transmission Layout With Parallel Superposition Gear Unit
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Solution Overview
Problem
Existing hybrid transmission devices for motor vehicles are not compact enough, leading to inefficient use of installation space between the internal combustion engine, electric machines, superposition gear unit, and differential.
Innovation Solution
A hybrid transmission device with a compact design, featuring a superposition gear unit arranged axially parallel to the transmission input shafts, a gear reduction stage with a countershaft, and multiple shift elements for implementing electrodynamic driving-off and hybridized drive modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional hybrid transmission layout is used, then the installation space between components is insufficient, but redesigning the layout increases complexity
Solution Approach 1:
The superposition gear unit is arranged axially parallel to the transmission input shafts rather than coaxially, utilizing a different spatial dimension. This axial parallel arrangement optimizes the use of installation space between the internal combustion engine, electric machines, and differential while maintaining a manageable structural complexity through standardized planetary gear components.
2Adaptability or versatility
If multiple shift elements are added to enable electrodynamic driving-off and hybridized drive modes, then drive mode flexibility is improved, but device complexity increases
Solution Approach 1:
The shift elements are designed to serve multiple functions: they not only enable electrodynamic driving-off mode and hybridized drive mode, but also control gear ratio changes and manage power flow distribution between the internal combustion engine and electric machines. This multi-functionality achieves comprehensive drive mode flexibility while minimizing the number of shift elements required.
3Volume of moving object
If the superposition gear unit is integrated coaxially with the output shaft, then compactness is improved, but accessibility for maintenance and assembly becomes difficult
Solution Approach 1:
The transmission is segmented into distinct functional modules: the superposition gear unit with planetary gears, the gear reduction stage with countershaft, and the differential assembly. This modular segmentation maintains compact overall volume while improving assembly accessibility, as each module can be independently manufactured, assembled, and maintained without requiring complete disassembly of the entire transmission.
Data Source
AI summary
A hybrid transmission device (1) includes a first transmission input shaft (2), a second transmission input shaft (4), a superposition gear unit (6) arranged axially parallel to the first transmission input shaft (2) and to the second transmission input shaft (4) and configured for connecting an electric machine (5). The superposition gear unit (6) includes a first planetary gear set (P1) with a sun gear (P11), a ring gear (P12), and a planet carrier (P13) with planet gears (P14) rotatably arranged thereon. A gear reduction stage (7) includes a first spur gear pair (ST1) and a second spur gear pair (ST2) for connecting the superposition gear unit (6) to a differential (8). At least a first shift element (A), a second shift element (B), and a third shift element (C) are configured for implementing an electrodynamic driving-off process and a purely electric or hybridized drive of the motor vehicle.