Resin Side Cover Oil Path for Electric Motor Cooling
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Solution Overview
Problem
Existing electric vehicle driving systems face efficiency degradation due to heat generation in electric motors, which is not effectively addressed by current cooling methods, leading to increased size, weight, and cost of transmission systems.
Innovation Solution
An electric vehicle driving system with a resin side cover that forms an oil path to supply a cooling lubricant to the heat-generating portions of the electric motor, including ejecting holes for pinpoint lubricant distribution, a radial oil feeding path, and a semicircular oil feeding path, which reduces the need for insulating members and allows for efficient cooling while suppressing radio noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water-cooling using a water jacket or oil-cooling using an oil pump is used to cool the electric motor, then the cooling effect is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines the side cover structure with the cooling lubricant supply function by forming an oil path directly within the side cover. This integration eliminates the need for separate cooling systems (water jacket or oil pump), reducing device complexity while maintaining effective cooling of the electric motor through the lubricant flow path.
Solution Approach 2:
The side cover is designed to serve multiple functions simultaneously: it provides mechanical protection for the electric motor, acts as a structural component of the casing, and functions as a cooling lubricant supply system through the integrated oil path. This multi-functionality reduces the number of separate components needed.
2Strength
If a metal side cover is used to cover the electric motor, then the structural strength is improved, but the insulating property deteriorates
Solution Approach 1:
The side cover is constructed using composite material technology, specifically incorporating resin material that provides both the necessary mechanical strength and electrical insulation properties. This composite structure eliminates the need for additional insulating members while maintaining both structural integrity and electrical isolation from the electric motor.
3Reliability
If the viscosity of the lubricant is increased at low temperature, then the lubrication property is improved, but the flow rate deteriorates
Solution Approach 1:
The patent controls the temperature parameter of the cooling lubricant by utilizing the heat generated from the electric motor during operation. As the motor operates, it heats the lubricant flowing through the oil path in the side cover, reducing the lubricant's viscosity and improving its flow rate while maintaining adequate lubrication properties.
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 system efficiently cools the electric motor, reduces the size and weight of the driving system, and simultaneously lubricates the transmission, enhancing cooling performance and reducing the number of components, thereby preventing efficiency degradation and radio noise interference.
Implementation Method 1
supplying a cooling lubricant to a heat generating portion of the electric motor
Implementation Method 2
the side cover forms an oil path that supplies a cooling lubricant to a heat generating portion of the electric motor
Data Source
AI summary
A side cover 82 which covers a side surface portion of an electric motor 7 is formed of a resin, and a lubricant is ejected from plural ejecting holes 95 of an oil path 90 formed in the side cover 82 to a stator 71 of the electric motor 7 so as to cool the stator.