Integrated Electric Drive System with Inverter-Motor Cooling
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Solution Overview
Problem
Conventional electric vehicle drive systems occupy large space due to separate housings of electric motors, inverters, and transmission devices, leading to increased assembly complexity and maintenance challenges, along with inadequate cooling due to non-uniform coolant channels.
Innovation Solution
A compact, high-integrated electric drive system where the electric motor, inverter, and transmission device are integrated with a cooling passage and fins to enhance cooling efficiency, allowing coolant to flow over the entire length of the motor's housing and improve space utilization by positioning the inverter between the output shaft and motor housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the electric motor, inverter and transmission device are designed as independent units with separate housings, then each component can be manufactured and maintained independently, but the overall system occupies large space and assembly complexity increases
Solution Approach 1:
The patent merges the electric motor, inverter and transmission device into a single integrated housing structure. The inverter is positioned within the space between the output shaft and motor housing, eliminating the need for separate housings and reducing overall system volume while maintaining independent manufacturability of sub-components
2Volume of moving object
If the electric motor, inverter and transmission device are integrated into a compact unit, then space occupation is reduced and assembly is simplified, but the cooling effectiveness may be compromised due to limited space for coolant channels
Solution Approach 1:
The patent utilizes the radial dimension by positioning the inverter between the output shaft and motor housing, and implements coolant channels that flow along the longitudinal axis of the motor housing. This three-dimensional arrangement of coolant flow paths ensures adequate cooling surface area and flow length despite the compact integrated structure
3Ease of manufacture
If separate electrical cables and bus-bars are used to connect the electric motor and inverter, then electrical connections are simple to implement, but assembly difficulty increases and maintenance becomes more complex
Solution Approach 1:
The patent integrates the electrical connections between the electric motor and inverter within the same housing structure. The inverter is positioned adjacent to the motor with direct mounting, eliminating the need for external electrical cables and bus-bars, thereby simplifying both assembly and maintenance operations
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 reduces space occupation, simplifies assembly, and enhances cooling efficiency by ensuring reliable cooling of both the electric motor and inverter, improving the overall performance and maintenance of the electric vehicle drive system.
Implementation Method 1
a cooling passage is provided in the housing of the electric motor such that the electric motor can be cooled down
Implementation Method 2
the housing of the inverter is in contact with the main shell such that an interface is defined between the main shell and the housing of the inverter, and the coolant flowing through the cooling passage is able to contact the interface
Data Source
AI summary
An electric drive system (100) used in an electric vehicle or a hybrid electric vehicle to drive the vehicle's wheels to rotate. The electric drive system (100) includes an electric motor (300). The electric motor (300) includes a housing in which a stator and a rotor are received. A transmission device (400) is operatively coupled to the electric motor (300); and an output shaft (500) is operatively coupled to the transmission device (400). The output shaft (500) extends from the transmission device (400) and is substantially parallel to the rotor's axis of the electric motor (300). The electric drive system (100) also includes an inverter (200) secured over the housing of the electric motor (300) such that the inverter is located between the output shaft (500) and the housing of the electric motor (300).