Electric Drive Unit Venting Layout to Prevent Oil Inlet Blocking
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Solution Overview
Problem
Existing electric drive units with integrated transmission stages face challenges in venting due to oil spray from rotating parts, which can block inlet openings and hinder pressure equalization, leading to potential oil escape and uneven oil distribution.
Innovation Solution
The drive unit features inlet openings strategically positioned in the central area of the housing, radially inside the rotor shaft's outer periphery, and equipped with mechanical screens to prevent oil ingress, ensuring venting channels remain clear and effective, with additional features like offset positioning and labyrinthine designs to maintain venting independence from rotation direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inlet openings are positioned in outer areas of the housing for venting, then venting function is provided, but oil spray from rotating components blocks the inlet openings
Solution Approach 1:
The inlet opening is repositioned from the outer peripheral area to the central area of the housing, changing the spatial dimension of the opening location. This central positioning places the inlet opening outside the oil spray trajectory generated by rotating components, thereby preventing oil blocking while maintaining venting functionality.
Solution Approach 2:
A mechanical screen is introduced as an intermediary element between the oil spray source and the inlet opening. The screen acts as a barrier that allows air to pass through for venting while blocking oil droplets from reaching and blocking the inlet opening.
2Object-affected harmful factors
If inlet openings are positioned in central area to avoid oil spray, then oil blocking is prevented, but venting efficiency may be reduced
Solution Approach 1:
The mechanical screen serves as an intermediary that maintains air flow paths while blocking oil. It allows sufficient air permeability to maintain venting efficiency while preventing oil droplets from reaching the inlet opening, thus resolving the trade-off between blocking prevention and venting efficiency.
3Object-affected harmful factors
If mechanical screens are added to inlet openings to prevent oil ingress, then oil blocking is prevented, but device complexity increases
Solution Approach 1:
The mechanical screen is applied locally only at the inlet opening area where oil ingress is a problem, rather than throughout the entire housing. This localized application provides oil protection while minimizing the overall structural complexity and material usage.
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 venting and pressure equalization, preventing oil from blocking inlet openings and maintaining consistent pressure across oil chambers, even in inclined positions, thus enhancing the operational reliability and efficiency of the drive unit.
Implementation Method 1
equipped with mechanical screens to prevent oil ingress
Implementation Method 2
ensuring venting channels remain clear and effective, with additional features like offset positioning and labyrinthine designs to maintain venting independence from rotation direction
Data Source
AI summary
The present disclosure relates to a drive unit (1) with a housing (2) and an electric motor (3) arranged therein. A transmission (8) is coupled to the electric motor (3). At least one oil chamber (15) is arranged in the housing (2), the oil chamber(s) having an oil zone (21) and an air zone (22), where the air zone (22) is flow-connected by way of an inlet opening (36) to a venting channel (35) that leads to a vent (32) such that the inlet opening (36) is arranged in a central area (40) of the housing (2) of the drive unit (1).