Hybrid Transmission Compact Design via Nested Planetary Gears
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hybrid vehicle transmissions face challenges in achieving a compact design with efficient gearing and low component loads while supporting various operating modes, including purely electric driving and tractive force support, due to complex arrangements of planetary gear sets and shift elements.
Innovation Solution
A transmission design featuring two planetary gear sets, multiple shift elements, and an electric machine connected to a second input shaft, allowing for selective actuation of power paths and gear shifts through clutches or brakes, with a compact layout and efficient gearing, enabling various operating modes by synchronizing rotational speeds and torques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gear sets and shift elements are arranged to support various operating modes, then the transmission can achieve diverse functions including purely electric driving and tractive force support, but the device complexity and component loads increase
Solution Approach 1:
The transmission system employs two planetary gear sets (first and second planetary gear sets) with multiple shift elements (first, second, third, and fourth shift elements) that can be selectively actuated to achieve different power paths and gear ratios. The electric machine can be connected to the second input shaft, enabling purely electric driving mode. The same transmission structure also supports hybrid driving modes with tractive force support from the prime mover, demonstrating multi-functionality across various operating conditions without requiring separate dedicated mechanisms for each mode.
2Volume of moving object
If a compact design is pursued with efficient gearing, then the transmission size is reduced, but the arrangement of planetary gear sets and shift elements becomes more constrained
Solution Approach 1:
The transmission system utilizes a nested arrangement where the first and second planetary gear sets are coaxially aligned and positioned in close proximity, with the electric machine integrated into the same space. The multiple input shafts and shift elements are arranged to share common mounting interfaces and spatial zones, creating a compact nested structure that minimizes the overall transmission volume while accommodating all necessary components for diverse operating modes.
Data Source
AI summary
A transmission (G) for a motor vehicle includes an electric machine (EM1), a first input shaft (GW1), a second input shaft (GW2), an output shaft (GWA), at least two planetary gear sets (P1, P2), and at least four shift elements (A, B, C, D). Different gears are selectable by selectively actuating the at least four shift elements (A, B, C, D). In interaction with the electric machine (EM1), different operating modes are implementable. A drive train for a motor vehicle that includes such a transmission (G) and to a method for operating same are also provided.