Passive Lubrication for Electric Vehicle Gear Drives

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Solution Overview

Problem

Existing lubrication systems in electric and hybrid-electric vehicles rely on power-consuming electric pumps to distribute oil to gear reduction systems, which consume significant power resources from batteries or electric power sources.

Innovation Solution

A passive lubrication system that utilizes a mechanical oil network, oil sump region, oil paddle, and oil diverter within the gear drive system to distribute oil without the need for electric pumps, leveraging the rotational motion of the planetary gear system to circulate oil through an oil network defined within a fixed annular region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electric pumps are used to distribute oil to gear reduction systems, then reliable lubrication is achieved, but power consumption increases significantly

Engineering Contradiction:

Improvelubrication reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The lubrication system uses the rotational motion of the planetary gear system itself to drive the oil paddle and circulate oil through the network, eliminating the need for external electric pumps. The system serves its own lubrication needs through its operational motion.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The electric pump (electromechanical system) is replaced with a passive mechanical oil circulation mechanism driven by the planetary gear rotation. The oil paddle and diverter use purely mechanical means to redirect oil flow without electrical components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If electric pumps and power consuming mechanisms are used for oil distribution, then adequate lubrication is provided, but device complexity increases

Engineering Contradiction:

Improvelubrication adequacyVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electric pump and associated power-consuming mechanisms are extracted and removed from the lubrication system. Only the essential passive components (oil paddle, diverter, and network) that leverage existing system motion are retained.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The planetary gear system serves dual functions: power transmission and oil circulation driving. The rotation required for gear operation also drives the oil paddle, combining lubrication function with the existing motion without requiring separate dedicated components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Use of energy by moving object

If passive lubrication without electric pumps is implemented, then power consumption is reduced, but oil distribution control becomes more challenging

Engineering Contradiction:

Improvepower consumptionVSAvoidoil distribution control

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The oil diverter acts as an intermediary component that passively redirects oil flow from the sump region to the network using the existing rotational motion and fluid dynamics, without requiring active control mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The oil distribution system uses dynamic motion of the rotating planetary gear to drive the oil paddle, which continuously circulates oil throughout the network. The system adapts to operational conditions through its inherent mechanical dynamics rather than static control.

Inventive Principle:

Principle #15Dynamics

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 solution reduces power consumption by eliminating the need for electric pumps, enhancing efficiency and robustness of the lubrication system, and simplifying the design of electric drive systems.

Implementation Method 1

The oil paddle may be operatively coupled with the planetary gear system, configured to rotate with a component of the planetary gear system, and during rotation, configured to course oil, from the oil sump region

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

it is greatly important that oil is distributed to components for lubrication during operation

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentUS10378642B2Passive lubrication system for concentric gear drive for an electric vehicle

Publication Date: 2019.08.13 BORGWARNER INC

AI summary

A passive lubrication system, for a gear drive system of a drive system, for powering an electric vehicle, includes an oil network, an oil sump region, an oil paddle, and an oil diverter. The oil network is defined by and disposed within, at least, a fixed annular region of the gear drive system and a planetary gear system. The oil sump region is configured to provide oil for distribution about the oil network. The oil paddle is operatively coupled with the planetary gear system, configured to rotate with a component of the planetary gear system, and during rotation, configured to course oil, from the oil sump region. The oil diverter is positioned concentric with the oil paddle and radially outward of the oil paddle and configured to receive oil from an oil source, upon rotation of the oil paddle, and direct the received oil to the oil network.