Electric Drive Gearbox Housing With Annular Calming Zone
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Solution Overview
Problem
The rapid rotation of coolant, particularly gearbox oil, in a planetary gear system creates difficulties in optimal lubrication and oil extraction due to high-velocity flow past the oil drain, hindering efficient circulation and drainage.
Innovation Solution
An annular calming zone is introduced in the gearbox housing, connected via individual openings, to stabilize coolant flow, with alternating open and closed sections, ensuring smoother flow and improved oil extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant is circulated at high speed in a planetary gear system, then cooling efficiency is improved, but oil extraction becomes difficult due to high-velocity flow past the oil drain
Solution Approach 1:
The housing interior is segmented into a high-speed cooling zone and a separate annular calming zone. The calming zone is connected to the main interior via individual openings, creating distinct flow regions. This segmentation allows high-speed coolant circulation for cooling while providing a separate low-velocity zone for effective oil extraction through the oil drain.
Solution Approach 2:
The annular calming zone acts as an intermediary between the high-speed cooling zone and the oil drain. Coolant flows from the high-speed zone through individual openings into the calming zone, where velocity is reduced before reaching the oil drain. This intermediary zone enables both efficient cooling and effective oil extraction by mediating the transition from high to low velocity.
2Productivity
If the annular chamber is completely open to the gearbox interior, then coolant circulation is maximized, but flow stabilization is insufficient for optimal oil extraction
Solution Approach 1:
The annular chamber wall exhibits local quality variations with alternating open sections and closed sections. The open sections allow coolant inflow from the high-speed zone, while the closed sections provide flow stabilization and create low-velocity regions. This local differentiation enables both adequate coolant circulation and flow stabilization for optimal oil extraction.
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 annular calming zone enhances coolant flow management, facilitating efficient lubrication and drainage by stabilizing the coolant flow, thereby improving the lubrication and cooling process.
Implementation Method 1
Especially when the gearbox is a planetary gear system, the gearbox oil rotates rapidly on the inside of the housing. This rotation creates an annular oil sump around the inside of the gearbox housing.
Data Source
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Figure 3~3a
AI summary
The invention relates to an electric drive unit for a motor vehicle, said drive unit comprising: an electric drive (5); a gearbox (6) connected downstream of the electric drive (5) in the power flow direction and located in a gearbox housing (4); means for circulating coolant in the interior (7) of the gearbox housing (4); and a rotatably mounted input or output shaft (19, 18) of the gearbox (6); wherein the gearbox housing (4) is composed of a housing shell (11), which annularly surrounds a central axis (A), and an end wall (13), and wherein the end wall (13) extends radially outwards from an opening (17) for the input or the output shaft (19, 18) as far as a connecting region (14) in which the end wall (13) and the housing shell (11) are connected to one another. In order to improve the flow conditions using design measures, in particular in those areas of the gearbox housing in which the coolant is discharged or suctioned out of the gearbox housing during circulation of same, an annular chamber (33) is provided which extends in the circumferential direction along the connecting region (14) and which is connected to the interior (7) via individual openings (40).