Shielding Shell Lubrication Channels for EV Transmission Drag Loss
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Solution Overview
Problem
Existing electric vehicle drive trains face challenges in efficiently lubricating transmission components while minimizing drag losses and fluid foaming, which affects the overall efficiency of the transmission assembly.
Innovation Solution
A transmission assembly with a housing containing a spur gearing and differential gearing, featuring a shielding shell that uses fluid-conducting channels to passively supply lubrication to components and actively return excess fluid to a sump, reducing drag losses and foaming through a multi-stage fluid distribution system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a shielding shell surrounds the output gear and differential cage below the fluid level, then drag losses are reduced, but fluid supply to transmission components becomes insufficient
Solution Approach 1:
The shielding shell is segmented with multiple fluid-conducting channels that divide and direct fluid flow to specific transmission components. The channels are arranged in stages to ensure systematic fluid distribution to the output gear, differential cage, and bearing pins while maintaining the shielding function.
Solution Approach 2:
Fluid-conducting channels act as intermediaries between the shielding shell and transmission components. These channels passively transport fluid from the sump area through the shielding shell to the gear meshing areas and bearing pins, ensuring reliable fluid supply without compromising the drag reduction benefit of the shielding.
2Reliability
If fluid-conducting channels are added to the shielding shell, then lubrication is improved, but device complexity increases
Solution Approach 1:
The fluid-conducting channels are integrated directly into the shielding shell structure, merging the shielding function with the fluid distribution function. This eliminates the need for separate fluid delivery mechanisms and reduces overall system complexity while ensuring reliable lubrication.
Solution Approach 2:
The fluid-conducting channels utilize the natural rotation of the output gear and differential cage to passively pump and distribute fluid throughout the transmission components. The system serves itself by using the motion of its own components to drive fluid circulation without requiring external pumping mechanisms.
3Loss of energy
If the shielding shell is closed and fluid-tight, then drag losses are minimized, but fluid circulation to components is hindered
Solution Approach 1:
The closed shielding shell is segmented with strategically placed fluid-conducting channels that allow controlled fluid circulation. The channels are positioned to capture fluid during gear rotation and redirect it to lubrication points, maintaining the fluid-tight enclosure while enabling necessary fluid exchange.
Solution Approach 2:
The fluid-conducting channels are designed to dynamically respond to the rotational motion of the gear components. The channels utilize centrifugal force and pressure differentials generated during operation to actively circulate fluid throughout the transmission, transforming the static shielding structure into a dynamic fluid distribution system.
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 provides improved lubrication efficiency, reduces drag losses, and minimizes fluid foaming, thereby enhancing the performance and efficiency of the transmission assembly.
Implementation Method 1
conveyed by a rotation of the output gear from the shell to at least one area in the transmission assembly that requires the fluid
Data Source
AI summary
A transmission assembly for a motor vehicle includes a transmission housing, a spur gearing in the housing having an input gear and an output gear, which are connected to one another, a differential gearing in the housing, wherein the differential gearing has a differential cage connected to the output gear for conjoint rotation, and numerous compensating gears rotatably supported in the cage, a sump that defines a fluid level in the transmission housing when the installed transmission assembly is stationary, and a shielding shell in the transmission housing, which surrounds the output gear and the differential cage, at least below the fluid level, to shield them against the sump, wherein the shell has a first channel, wherein fluid in the shell can be conveyed from the shell along the first channel to at least one area in the transmission assembly.