E-Drive Rotor Shaft Baffle for Low-Pressure Cooling Flow
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Solution Overview
Problem
E-axles require effective rotor cooling without adding significant costs, components, or complexity, while managing fluid flow to avoid pressure drops and interaction with high-speed rotating parts.
Innovation Solution
Incorporation of baffles and tapered surfaces in the fluid flow path to redirect cooling fluid away from rotating components, using sloped connector rings to minimize pressure drops and shield fluid from high-speed rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If active rotor cooling is implemented, then heat dissipation performance is improved, but device complexity and cost increase
Solution Approach 1:
The baffle is integrated into the housing structure, merging the fluid redirection function with the existing housing component. This eliminates the need for separate cooling components while achieving effective rotor cooling through the fluid flow path configured within the housing and rotor shaft assembly
Solution Approach 2:
The rotor shaft itself serves as a cooling channel by defining a hollow interior space that conducts cooling fluid. The housing structure also serves dual purposes by incorporating passages and baffles that guide fluid flow without requiring additional dedicated cooling components
2Temperature
If cooling fluid is directed through the rotor shaft hollow, then cooling efficiency is improved, but pressure drops occur due to interaction with rotating parts
Solution Approach 1:
The baffle acts as an intermediary element that redirects cooling fluid away from rotating components. It mediates between the fluid flow path and the rotor shaft/output shaft, preventing direct interaction that would cause pressure drops while maintaining effective cooling through the rotor shaft hollow
3Ease of operation
If multiple baffles are added to redirect fluid flow, then fluid flow control is improved, but device complexity increases
Solution Approach 1:
The housing structure performs multiple functions: it provides structural support, defines fluid flow passages, and incorporates baffles for flow redirection. This multi-functionality achieves precise fluid flow control without adding numerous separate components, as the housing serves as an integrated platform for all these functions
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
Efficient rotor cooling is achieved with reduced pressure loss and component count, protecting fluid from rotating parts and optimizing space utilization.
Implementation Method 1
The baffle is arranged to redirect fluid flowing along the fluid flow path away from a portion of at least one of the rotor shaft and the output shaft
Implementation Method 2
a portion of the inner surface tapers radially outboard as the portion of the inner surface extends axially away from the axial end of the rotor shaft
Data Source
AI summary
An electric drive unit includes an electric motor having a rotor shaft that defines a hollow that is accessible via an opening defined at an axial end of the rotor shaft. The hollow defines a portion of a fluid flow path. The electric drive unit also includes an output shaft that extends into the hollow through the opening. The electric drive unit further includes a baffle that extends into the hollow through the opening. The baffle is arranged to redirect fluid flowing along the fluid flow path away from a portion of at least one of the rotor shaft and the output shaft.