Nested Dual-Motor Drive Assembly for Compact Axial Packaging
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Solution Overview
Problem
Existing drive units for hybrid motor vehicles face challenges in optimizing space usage and cost-effectiveness, particularly in front-transverse arrangements where electric rotary machines and internal combustion engines are used as front drives, requiring a compact and efficient design.
Innovation Solution
The drive unit incorporates two electric rotary machines with one arranged radially and axially within the other, a separating clutch for torque transmission, and a central bearing system, allowing for coaxial rotation axes and a compact stator arrangement, which reduces axial installation space and enables efficient torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If two electric rotary machines are arranged side by side or coaxially in conventional configurations, then torque transmission capability is achieved, but axial space requirements increase
Solution Approach 1:
The first electric rotary machine is arranged radially and axially within a space radially delimited by the second electric rotary machine, creating a nested configuration where one motor is positioned inside the radial envelope of the other. This nesting approach allows both motors to share the same axial space while maintaining their individual torque transmission capabilities, thereby reducing the overall axial length of the drive unit without compromising power output.
Solution Approach 2:
The invention transitions from conventional side-by-side or simple coaxial arrangements to a three-dimensional nested configuration. By utilizing the radial dimension more effectively and positioning one motor within the radial envelope of the other, the design optimizes spatial utilization in all three dimensions (radial, axial, and tangential), achieving compact axial length while preserving dual motor functionality.
2Length of moving object
If electric rotary machines are arranged to minimize axial space, then space efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The separating clutch serves multiple functions: it enables independent operation of each electric rotary machine, allows for torque transmission from either or both motors to the second shaft, and provides flexibility for different operating modes (electric driving, hybrid operation, regenerative braking). This multi-functionality reduces the need for additional specialized components, thereby managing manufacturing complexity while achieving the compact nested arrangement.
Solution Approach 2:
The drive unit is segmented into functionally independent modules: the first electric rotary machine with its own control, the second electric rotary machine with its own control, the separating clutch for selective torque transmission, and the central bearing system. This modular segmentation allows each component to be manufactured and tested independently, then assembled into the compact nested configuration, thereby managing overall manufacturing complexity despite the space-optimized design.
3Adaptability or versatility
If a separating clutch is added for torque transmission control, then operational versatility improves, but device complexity increases
Solution Approach 1:
The separating clutch is integrated into the torque transmission path between the first electric rotary machine and the second shaft, merging the torque transmission functions of both motors through a single control mechanism. This integration allows the separating clutch to manage torque from either or both motors without requiring separate control systems for each torque path, thereby providing operational versatility while limiting the increase in device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration minimizes axial space requirements, allows for various operating modes including electric driving and hybrid operation, and provides a cost-effective solution by optimizing the use of space and components.
Implementation Method 1
a first electric rotary machine (10) and a second electric rotary machine (20)... wherein a rotor (11) of the first electric rotary machine (10) is connected in a rotationally fixed manner to a first shaft (40) and a rotor (21) of the second electric rotary machine (20) is connected in a rotationally fixed manner to a second shaft (41)
Implementation Method 2
a central bearing system, allowing for coaxial rotation axes
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a drive unit for the powertrain of an electrically drivable motor vehicle, in particular a hybrid motor vehicle, and to a drive assembly. The drive unit (1) comprises a first electric rotary machine (10) and a second electric rotary machine (20) as well as a first shaft (40) and a second shaft (41), wherein a rotor (11) of the first electric rotary machine (10) is rotationally fixed to the first shaft (40), and a rotor (21) of the second electric rotary machine (20) is rotationally fixed to the second shaft (41). The drive unit (1) additionally has a separating clutch (50). According to the invention, one of the two electric rotary machines (10, 20) is arranged at least partly radially and axially within an area radially delimited by the respective other electric rotary machine (10, 20). An optimal operation can be ensured in an inexpensive and particularly space-saving manner by virtue of the drive unit and the drive assembly according to the invention.