Rotor-Transmission Spline Lubrication Using Centrifugal Oil Flow
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Solution Overview
Problem
Existing drive units for vehicles face challenges in efficiently lubricating and cooling the interlocking toothing between the electric machine's rotor shaft and the transmission's transmission shaft, leading to potential wear and increased operational temperatures.
Innovation Solution
The drive unit incorporates an interlocking toothing between the rotor shaft and the transmission shaft, with a lubricant channel in the transmission shaft that feeds into the rotor shaft's inner space, and strategically placed openings on the rotor shaft's end side to facilitate lubricant distribution via centrifugal force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate lubrication system is used for the interlocking toothing, then lubrication effectiveness is improved, but device complexity and installation space increase
Solution Approach 1:
The patent combines the lubrication system with the rotor shaft by forming a lubricant channel directly in the rotor shaft that feeds into the interlocking toothing. This integration eliminates the need for separate lubrication components and systems, thereby maintaining reliable lubrication while reducing device complexity and installation space.
Solution Approach 2:
The rotor shaft is designed to serve multiple functions: it supports the rotor, transmits torque, and simultaneously acts as a lubricant delivery system through the integrated lubricant channel. This multi-functionality reduces the number of separate components needed, addressing both lubrication effectiveness and system complexity.
2Reliability
If a separate lubrication system is used for the interlocking toothing, then lubrication effectiveness is improved, but weight increases
Solution Approach 1:
By merging the lubricant channel into the rotor shaft structure itself, the patent eliminates the need for separate lubrication components, hoses, and reservoirs that would add weight. The integrated design maintains effective lubrication delivery while minimizing the overall system weight.
3Volume of moving object
If lubricant is guided through existing components, then installation space is reduced, but manufacturing complexity increases
Solution Approach 1:
The lubricant channel is formed directly in the rotor shaft as an integrated feature, allowing lubricant to be guided through existing components without requiring additional separate lubrication pathways. This integration minimizes installation space while the channel can be manufactured using standard machining processes.
4Productivity
If centrifugal force is used to guide lubricant to the interlocking toothing, then lubrication efficiency is improved, but the system requires rotational motion
Solution Approach 1:
The system uses the rotational motion already inherent in the operation of the interlocking toothing to generate centrifugal force that guides the lubricant to where it is needed. The rotation of the rotor shaft itself provides the driving force for lubrication, eliminating the need for separate pumping mechanisms and improving lubrication efficiency while maintaining operational flexibility.
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 design enhances lubrication and cooling of the interlocking toothing, allowing for further lubrication and cooling of transmission components, thereby reducing wear, minimizing weight, and achieving a more compact and cost-effective installation.
Implementation Method 1
When the rotor shaft or transmission shaft is rotating, the lubricant is guided radially outward to the interlocking toothing by centrifugal force
Data Source
AI summary
The invention relates to a drive unit (10) for a vehicle, comprising an electric machine (12) having a rotor shaft (14) and a transmission (16) having a transmission shaft (18). According to the invention, the rotor shaft (14) and the transmission shaft (18) are interlocking and coupled by means of an interlocking toothing (44), wherein a lubricant channel (46) is formed in the transmission shaft (18), which feeds into an inner space (48) of the rotor shaft (14) at the end facing the rotor shaft (14) in order to provide lubricant for the interlocking toothing (44), wherein the rotor shaft (14) has an end side (50) at the axial end facing the transmission shaft (18), on which end side one or more openings (52) are formed, extending from an inner circumference (54) of the rotor shaft (14) bordering the inner space (48) to the outer circumference (56) thereof, such that the lubricant channel (46) is fluidically connected to the openings (52) via the inner space (48) and the interlocking toothing (44).