Modular Electrically Variable Transmission Design
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Solution Overview
Problem
Conventional multi-mode electrically variable transmissions (EVTs) for hybrid vehicles are not optimized to share core components, limiting their cost-effective use in both front wheel drive and rear wheel drive applications and requiring redesign for different configurations, thus lacking in maximizing the capability of the main electric motor and providing shift-free input-output split.
Innovation Solution
A modular electrically variable transmission design featuring two sun-shared modules that can be coupled in coaxial or axially offset configurations, allowing for sharing of main planetary gear components and enabling cost and manufacturing synergies, with an optional input brake for electric-only mode and brake-free hill holding capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional multi-mode EVTs are designed for specific applications (FWD or RWD), then the transmission can be optimized for that specific purpose, but the device complexity and manufacturing cost increase due to requiring separate designs for different configurations
Solution Approach 1:
The patent implements a universal EVT core design that can be configured for both front wheel drive and rear wheel drive applications through modular assembly variations. The core EVT components remain identical across applications, while only the coupling configuration changes to accommodate different drive types, eliminating the need for separate redesigns and reducing manufacturing complexity.
2Productivity
If the EVT core is integrated without modular components, then the transmission can provide continuous variable ratios, but the manufacturing cost and complexity increase due to lack of component sharing
Solution Approach 1:
The patent segments the EVT into modular components including the EVT core, MSR subassembly, and coupling mechanisms. These modular segments can be manufactured independently using standardized processes and then assembled in different configurations, reducing manufacturing cost while preserving the continuous variable transmission capability of the integrated EVT core.
3Power
If the main electric motor capability is maximized in conventional EVTs, then the electric motor can provide higher power output, but the transmission requires additional components that increase device complexity
Solution Approach 1:
The patent merges the EVT core with the MSR (motor speed reducer) subassembly into an integrated modular unit. This combination allows the main electric motor to operate at optimal speeds while the integrated MSR provides necessary speed reduction, maximizing electric motor capability without requiring separate, additional components that would increase overall device complexity.
Data Source
Figure 1
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Figure 3~3A
AI summary
A modular electrically variable transmission includes a sun-shared module (60) and a sun and ring-shared module (70) assembled to form a two-module electrically variable transmission (10) having a shiftable motor speed reducer subassembly (50) and an electrically variable transmission subassembly (40). The sun-shared module (60) includes a first motor-generator (54), an input (80), and primary and secondary planetary gear sets each having respective primary and secondary ring gears (96, 110), carriers (88, 102) and associated pinion gears (92, 106). The pinion gears (92, 106) are in meshing engagement with a single first shared sun gear (84) non-rotatably coupled to the first motor-generator (54). The sun and ring-shared module (70) includes a second motor-generator (44), input (174), shared sun gear (120) and shared ring gear (124), and primary and second secondary planetary gear sets. The secondary planetary gear set includes a secondary carrier (142) supporting outer and inner pinion gears. The second shared sun gear (120) is non-rotatably coupled to the second motor-generator (44).