Nested Electric Drive Assembly With Shared Stator Cooling
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Solution Overview
Problem
Existing drive units for hybrid motor vehicles face challenges in optimizing cooling and space efficiency due to the axial arrangement of electric rotary machines, which complicates cooling and increases installation space requirements.
Innovation Solution
A drive unit design featuring radially nested electric rotary machines with a coolant supply system that distributes coolant between the stators, allowing for efficient cooling and reduced axial space usage, along with a separating clutch for torque transmission and various operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electric rotary machines are arranged axially side by side, then cooling can be provided through separate outlets, but the axial length and installation space increase
Solution Approach 1:
The first electric rotary machine is arranged radially inside the second electric rotary machine, with the rotor of the first machine positioned within the stator of the second machine. This nested configuration allows both machines to share the same axial space, dramatically reducing the overall axial length of the drive unit while maintaining the ability to cool both machines through the single central coolant supply device
Solution Approach 2:
The first coolant outlet is designed to serve dual purposes: it provides cooling for both the first electric rotary machine (through its own cooling channels) and the second electric rotary machine (by directing coolant to the second stator). This multi-functional outlet eliminates the need for separate cooling systems for each machine, reducing structural complexity while maintaining effective cooling of both machines in the compact radial arrangement
2Length of moving object
If electric rotary machines are arranged radially nested, then axial space is reduced, but cooling system complexity increases
Solution Approach 1:
The first coolant outlet is designed to serve dual purposes: it provides cooling for both the first electric rotary machine (through its own cooling channels) and the second electric rotary machine (by directing coolant to the second stator). This multi-functional outlet eliminates the need for separate cooling systems for each machine, reducing structural complexity while maintaining effective cooling of both machines in the compact radial arrangement
Solution Approach 2:
The cooling systems of both electric rotary machines are merged into a single integrated coolant supply device with shared coolant channels. The first and second coolant channels are combined in the housing, allowing a single coolant supply to serve both machines simultaneously, thereby simplifying the overall cooling system structure despite the radial nesting configuration
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
The solution enables optimal cooling and efficient operation of the drive unit in a compact, space-saving design, supporting various driving modes and reducing installation space requirements while maintaining efficient cooling of both stators and rotors.
Implementation Method 1
a first flow system for realizing a flow of a first fluid for at least partially cooling at least one electric rotary machine
Implementation Method 2
heat is transferable from the first flow system to the second flow system via a heat exchanger
Data Source
AI summary
A drive unit has a first electric rotary machine and a second electric rotary machine as well as a first shaft and a second shaft. The first electric rotary machine is arranged at least partly radially and axially within an area radially delimited by the second electric rotary machine, and the stator of the first electric rotary machine and the stator of the second electric rotary machine are mechanically fixed to each other. The drive unit comprises a coolant supply device which is arranged adjacently to the stators in the axial direction and by means of which coolant can be supplied axially between and/or into the stators.