Modular Transmission Layout for Compact EV Powertrain Packaging

The transmission unit employs a nested arrangement where the first, second, and third transmission shafts are coaxially aligned, with gear wheels nested on these shafts. The first gear wheel is nested on the first transmission shaft, the second and third gear wheels are nested on the second transmission shaft, and the fourth and fifth gear wheels are nested on the third transmission shaft. This nesting approach minimizes the radial footprint while maintaining the necessary functional extensions, enabling the transmission unit to fit compact spaces while preserving connectivity to propulsion units and other components.

The patent transitions from a traditional multi-directional gear arrangement to a primarily axial configuration. By aligning the transmission shafts coaxially and arranging gear wheels along the axial direction rather than radially, the design achieves compactness in the radial dimension while extending appropriately in the axial dimension. This dimensional reorganization allows the transmission unit to maintain sufficient extension for component connections while reducing overall volume occupation.

The two gear rows in the transmission unit are designed with universal applicability to serve multiple functions and configurations. The first gear row (comprising first, second, and fifth gear wheels) and the second gear row (comprising third and fourth gear wheels) can be selectively engaged through the coupling device to provide different transmission ratios. This multi-functional design enables the same two gear rows to satisfy various end user requirements including different power take-offs, retarder connections, and auxiliary connections, eliminating the need for additional gear rows while maintaining versatility.

The transmission unit incorporates a coupling device that enables dynamic selection between different gear wheel engagements. The coupling device can selectively couple the fifth gear wheel to the third transmission shaft and the fourth gear wheel to the third transmission shaft, allowing the system to adapt its transmission characteristics based on operational requirements. This dynamic engagement capability ensures that only two gear rows are needed to provide multiple transmission ratios and configurations, reducing device complexity while maintaining the ability to meet diverse end user needs.

The transmission unit is designed as a universal component that can function in both central drive and electric axle configurations. The coaxial arrangement of the first, second, and third transmission shafts, combined with the selective coupling capability of the coupling device, creates a platform that can be adapted to different vehicle architectures. The same basic transmission unit structure serves multiple functions: it can connect to propeller shafts in central drive configurations or directly to wheel axles in electric axle configurations, eliminating the need for configuration-specific designs and reducing overall system complexity.

The transmission unit is segmented into modular components: the first transmission shaft with its gear wheel, the second transmission shaft with its gear wheels, the third transmission shaft with its gear wheels, and the coupling device. This segmentation allows the transmission unit to be configured for different applications by selectively engaging or disengaging specific components. The modular segmented design enables the same transmission unit to be adapted to both central drive and electric axle configurations without increasing inherent design complexity, as the segmentation provides natural adaptation points for different connection requirements.