Modular Electric Axle Layout With Multi-Ratio Transmission
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Solution Overview
Problem
Existing electric drive units and transmissions face compatibility issues with certain vehicle platforms and exhibit inefficiencies due to fixed gear ratios and motor configurations.
Innovation Solution
An electric axle design featuring a transmission with an input shaft having mechanical interfaces on both sides, allowing for coaxial arrangement of electric machines and a differential, enabling modular design and flexible operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If motors are positioned fore and aft of the axle shaft in Schneider's drive unit, then the drive unit can be configured with a single speed transmission, but the drive unit exhibits inefficiencies during certain operating conditions due to the inability to alter transmission gear ratio and is incompatible with certain vehicle platforms
Solution Approach 1:
The input shaft is divided into two separate mechanical attachment interfaces positioned at opposite ends, allowing independent coupling of electric machines or other components. This segmentation enables flexible configuration options including single motor, dual motor, or alternative component arrangements, thereby increasing adaptability to different vehicle platforms while maintaining manufacturing simplicity.
2Device complexity
If Schneider's single speed drive unit is used, then the structure is simplified, but the drive unit exhibits inefficiencies during certain operating conditions due to the unit's inability to alter the transmission's gear ratio
Solution Approach 1:
The transmission system incorporates a clutch mechanism that enables dynamic shifting between at least two gear ratios, allowing the system to adapt its transmission characteristics based on operating conditions. This dynamic capability improves operational efficiency across different driving scenarios while maintaining a relatively simple overall structure through the use of a single clutch-based shifting mechanism.
3Ease of manufacture
If motors are arranged in series as in Karlsson's drive unit, then the drive unit can be configured with series arrangement, but the architecture constrains the modalities in which the drive unit can be operated
Solution Approach 1:
The input shaft is designed with two mechanical attachment interfaces that can accommodate various component configurations. The system supports multiple operational modalities including: (1) single electric machine operation, (2) dual electric machine operation in series, (3) dual electric machine operation in parallel, or (4) alternative component arrangements. This universal interface design enables the same basic structure to fulfill multiple functional requirements without constraining operational flexibility.
4Device complexity
If the transmission uses a fixed gear ratio, then the structure is simplified, but the drive unit exhibits inefficiencies during certain operating conditions
Solution Approach 1:
The transmission incorporates a clutch mechanism that enables dynamic selection between at least two different gear ratios based on operating conditions. This allows the transmission to optimize efficiency by selecting the appropriate gear ratio for different speed and load conditions, reducing energy losses while maintaining a relatively simple overall transmission structure through the use of a single clutch-based shifting system.
Data Source
AI summary
Systems and methods for an electric axle. In one example, the electric axle includes an electric machine removably coupled to a first side of an input shaft via a first mechanical attachment interface and a differential rotationally coupled to a transmission. The transmission includes the input shaft that includes a second mechanical interface on a second side that is opposite the first side and a clutch mounted on an intermediate shaft or the input shaft and configured to shift the transmission between at least two gear ratios.