Vehicle Axle Coolant Return Layout for Cornering Reliability
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Solution Overview
Problem
In electrically operated two-track vehicles, the coolant supply system for the drive device of the vehicle axle faces challenges in reliably circulating coolant during various driving conditions, particularly due to coolant shifting away from the suction point under centrifugal force.
Innovation Solution
The coolant supply system incorporates a stator housing sump with suction points on both axially opposite sides, ensuring reliable coolant suction and circulation across different driving conditions. This design includes a flow connection to the transmission sump, allowing coolant from the stator housing sump to be directed into the transmission sump during cornering, thereby ensuring continuous coolant return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a central suction point is used in the stator housing sump, then the structure is simple, but reliable coolant return is impaired under centrifugal force during dynamic driving conditions
Solution Approach 1:
The single central suction point is segmented into multiple suction points distributed at different locations in the stator housing sump. This segmentation ensures that at least one suction point remains effective regardless of coolant distribution caused by centrifugal force during acceleration, curving, or downhill driving, thereby resolving the contradiction between reliability and structural simplicity.
2Reliability
If the coolant tank capacity is increased to accommodate coolant displacement, then coolant circulation reliability improves, but the vehicle axle structure becomes more complex and larger
Solution Approach 1:
Multiple suction points are preliminarily positioned in the stator housing sump to anticipate and accommodate coolant displacement under centrifugal force before it occurs. This preliminary arrangement of suction points eliminates the need to increase coolant tank capacity, maintaining compact vehicle axle dimensions while ensuring reliable coolant return under all driving conditions.
3Reliability
If additional suction points are added to the stator housing sump, then coolant return reliability under centrifugal force improves, but the sump structure becomes more complex
Solution Approach 1:
Suction points are strategically positioned at specific locations within the stator housing sump based on local coolant accumulation patterns under different driving conditions. This localized placement of suction points provides targeted coolant extraction where needed most, achieving reliable coolant return with minimal additional structural complexity compared to a single central suction point.
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 ensures reliable coolant circulation and return to the coolant tank across various driving conditions, including cornering, by utilizing dual suction points and a flow connection to the transmission sump, thereby maintaining efficient operation of the electric machine.
Implementation Method 1
at which the collected coolant can be sucked off by the return pump
Implementation Method 2
the coolant collected in the stator housing sump can shift away from the sump suction point due to centrifugal force
Data Source
AI summary
A coolant supply system for a drive device of an electrically operated vehicle axle of a two-track vehicle with an electric machine. The coolant supply system has an electric machine hydraulic circuit in which a coolant tank, the interior of a cylindrical stator housing and a stator housing sump are integrated, in which the coolant draining from the stator housing collects, which can be returned from there to the coolant tank by at least one return pump. The stator housing sump has a suction point on each of its axially opposite axial sides, from which the coolant can be sucked off by the return pump.