Vehicle Electric Motor Cooling With Stator-Casing Grooves
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Solution Overview
Problem
Existing electric motors for motor vehicles face challenges in cooling, reducing weight and dimensions, increasing torque and power density, minimizing component count, and facilitating installation while minimizing alterations to the rotor and stator.
Innovation Solution
An electric motor design featuring a tubular stator with a coaxially housed rotor, a cooling circuit with a heat transfer fluid, and a stator mounted through interference onto a casing, utilizing grooves and appendages for angular timing and fluid tightness, reducing the need for additional parts and facilitating installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling circuit is added to the electric motor, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The cooling circuit is merged with the existing stator structure by integrating cooling channels directly into the stator body. The stator serves dual functions: generating magnetic fields through its windings and dissipating heat through its integrated cooling channels, eliminating the need for separate cooling components and reducing overall device complexity.
Solution Approach 2:
The stator is designed with multi-functionality, serving both as the electromagnetic component that generates the rotating magnetic field and as the thermal management component with integrated cooling channels. This universal design allows a single component to perform multiple functions, improving cooling efficiency without proportionally increasing device complexity.
2Weight of moving object
If the number of components is reduced, then weight and dimensions are reduced, but manufacturing complexity increases
Solution Approach 1:
Multiple components are merged into integrated assemblies. The stator incorporates both the winding structure and cooling channels as a single integrated component. The rotor combines the shaft, permanent magnets, and balancing elements into a unified rotating assembly. This merging reduces the total number of parts and overall weight while the modular integrated design facilitates manufacturing.
Solution Approach 2:
The motor is divided into distinct modular segments (stator assembly, rotor assembly, housing) that can be manufactured separately and then assembled. This segmentation allows each module to be optimized for its specific manufacturing process while reducing the complexity of manufacturing the entire motor as a single complex component.
3Manufacturing precision
If interference mounting is used for the stator, then assembly precision is improved, but manufacturing complexity increases
Solution Approach 1:
The stator is pre-assembled with its cooling channels and windings integrated before being mounted onto the motor housing. The rotor is pre-balanced and pre-assembled with its permanent magnets before installation. These preliminary actions ensure precise positioning and proper alignment are achieved during the pre-assembly stage, facilitating the subsequent interference mounting process and reducing on-site adjustment requirements.
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 design achieves reduced weight and dimensions, increased torque and power density, and efficient cooling without altering the rotor and stator significantly, while ensuring fluid tightness and safety from electrical components.
Implementation Method 1
a cooling circuit 50 through which a heat transfer fluid can flow and thermally coupled to the stator 3 to remove heat from it
Implementation Method 2
a cooling circuit 50 through which a heat transfer fluid can flow
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An electric motor (2) for a motor vehicle (1) is described, comprising a stator (3) which is fixed relative to an axis (A); a rotor (4) which can rotate around an axis (A) relative to the stator (3); a casing (30) housing the rotor (4) and the stator (3); a cooling circuit (50) through which a heat transfer fluid can flow and which is thermally coupled at least to the stator (3) to remove heat from it; the stator (3) is forced, through interference, onto the casing (30); the cooling circuit (50) comprising, in turn, an inlet mouth (51) defined by the casing (30) and crossed by the heat transfer fluid having a first temperature; and an outlet mouth (52) defined by the casing (30) and crossed by the heat transfer fluid having a second temperature higher than the first temperature; the cooling circuit (30) comprises, proceeding from the inlet mouth (51) towards the outlet mouth (52), a first branch (55) going through the stator (3); a second branch (56) defined by at least one groove (65) delimited, radially to the axis (A), between the stator (3) and the casing (30).