Integrated Gearbox in Electric Motor Rotor
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Solution Overview
Problem
Existing electric vehicle systems with integrated gearboxes, motors, and power inverters face complexity due to differing thermal characteristics, leading to increased cooling system complexity and cost.
Innovation Solution
Integrating a planetary gear set and differential within the rotor of an electric motor to simplify the cooling and lubrication systems, sharing coolant and lubrication between the gearbox and motor, thereby reducing weight and volume while enhancing cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the gearbox, power electronics, and electric motor are integrated into a single unit, then weight and volume are reduced, but thermal management complexity increases due to different operating temperatures
Solution Approach 1:
The patent divides the integrated drive unit into two separate cooling zones: a first cooling zone for the gearbox and a second cooling zone for the power electronics. This segmentation allows each component to be cooled independently at its optimal temperature, reducing thermal management complexity while maintaining the weight and volume benefits of integration.
Solution Approach 2:
The patent applies different cooling characteristics to different parts of the integrated drive unit. The gearbox operates at higher temperatures (up to 100°C) while the power electronics operate at lower temperatures (40°C to 50°C). By providing localized cooling zones with appropriate temperature control for each component, the system achieves efficient thermal management without excessive complexity.
2Device complexity
If multiple distinct components are used for gearbox, power electronics, and electric motor, then thermal management is simpler for each component, but overall system weight and volume increase
Solution Approach 1:
The patent merges the gearbox, power electronics, and electric motor into a single integrated drive unit with a common housing. This consolidation reduces overall system weight and volume while incorporating a unified cooling system with separate cooling zones that manages the thermal requirements of each component independently.
Solution Approach 2:
The common housing serves multiple functions: it encloses the gearbox, power electronics, and electric motor, and also provides the cooling structure with integrated cooling zones. This multi-functional design reduces the need for separate cooling systems for each component, thereby reducing overall system weight and volume.
3Power
If the gearbox operates at high temperatures up to 100°C, then gearbox performance is improved, but the power electronics must be thermally isolated to maintain lower operating temperatures of 40°C to 50°C
Solution Approach 1:
The cooling system is segmented into distinct cooling zones: a first cooling zone for the gearbox that allows high-temperature operation (up to 100°C) and a second cooling zone for the power electronics that maintains lower temperatures (40°C to 50°C). This segmentation provides thermal isolation without requiring complex active cooling barriers.
Solution Approach 2:
The patent extracts the thermal management requirements of different components into separate cooling zones within the common housing. By taking out the thermal isolation requirement and implementing it through separate cooling zones rather than complex thermal barriers, the system achieves both high gearbox temperature performance and power electronics temperature control.
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
This configuration results in a compact, cost-effective propulsion system with simplified cooling and lubrication, reducing packaging space and operational complexity.
Implementation Method 1
a cooling system may be included, the cooling system comprising a pump and a heat exchanger coupled to one another via a first fluidic channel
Implementation Method 2
a lubrication system may be included, the lubrication system comprising a reservoir and a pump coupled to one another via a second fluidic channel
Implementation Method 3
A first planetary gear set may be included, the first planetary gear set comprising a first sun gear, a first planet gear, a first carrier, and a first ring gear
Data Source
AI summary
Methods and systems are provided for integrating a gearbox into an electric motor. In one example, a system may include enclosing a gearbox containing a planetary gear set and a differential within an envelope of a rotor of the electric motor.