Motor Unit Oil Cooling via Partitioned Chamber Dynamics

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Solution Overview

Problem

Existing motor units require a large amount of oil to maintain the oil level, leading to increased weight and energy consumption for cooling, as the oil level in the motor case does not change effectively.

Innovation Solution

A motor unit design with a partitioned housing space that allows oil to be transferred from a lower region in the motor chamber to a gear chamber, utilizing a partition opening to increase the oil transfer and reduce the oil level in the motor chamber, thereby optimizing oil usage and reducing weight and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the oil level in the motor case is maintained at a constant level, then the motor can be adequately cooled and lubricated, but a large amount of oil is required, increasing weight and energy consumption for cooling

Engineering Contradiction:

Improvecooling and lubrication effectivenessVSAvoidweight of oil

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The partition opening enables dynamic oil level adjustment in the motor case. As oil is consumed or temperature changes, the oil level automatically adjusts through the partition opening, maintaining adequate cooling and lubrication without requiring a large fixed oil volume. The oil level in the motor case can rise or fall relative to the gear case, optimizing oil usage while ensuring reliable operation.

Inventive Principle:

Principle #15Dynamics

2Reliability

If a large amount of oil is used to maintain constant oil level, then adequate lubrication is ensured, but energy consumption for cooling increases

Engineering Contradiction:

Improvelubrication effectivenessVSAvoidenergy consumption for cooling

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The partition opening creates a dynamic oil level system that adjusts oil volume based on actual operational needs. When the motor generates more heat, the oil level naturally rises to provide better cooling. When heat generation is lower, the oil level decreases, reducing the amount of oil that needs to be cooled and thus lowering energy consumption while maintaining adequate lubrication.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system allows oil level parameter to change dynamically between the motor case and gear case. The partition opening enables the oil level in the motor case to vary relative to the gear case, optimizing the balance between lubrication effectiveness and cooling energy requirements based on operational conditions.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If the oil level in the motor case does not change, then stable lubrication is maintained, but the amount of oil required increases weight

Engineering Contradiction:

Improveoil level stabilityVSAvoidweight of oil

Core Design Contradiction:

Stability of the object's compositionVSWeight of stationary object

Solution Approach 1:

The partition opening enables dynamic oil level adjustment between the motor case and gear case. The oil level in the motor case can rise or fall relative to the gear case based on operational conditions, allowing the system to maintain stable lubrication at the oil outlet while using less total oil, thereby reducing weight.

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 design reduces the amount of oil needed, minimizing weight and energy consumption while maintaining effective lubrication and cooling for the motor and gear components.

Implementation Method 1

A bottom portion of the motor chamber is higher than a bottom portion of the gear chamber. A vertically lower region of the partition includes a partition opening to bring the gear chamber and the motor chamber into communication with each other.

Methodology Applied

Scientific EffectGravity: Gravitation

Implementation Method 2

an oil passage to lead the oil from the vertically lower region of the housing space to be fed to the motor

Methodology Applied

Scientific EffectFluid flow through passage:

Implementation Method 3

The partition opening is structured such that a rise in a liquid surface of the oil in the vertically lower region of the motor chamber causes an increase in an amount of transfer of the oil from the motor chamber to the gear chamber through the partition opening.

Methodology Applied

Scientific EffectHydraulic communication:

Data Source

PatentUS11616419B2Motor unit with oil cooling passage

Publication Date: 2023.03.28 NIDEC CORP(JP)

AI summary

A motor unit includes a motor including a rotor and a stator, a gear connected to the rotor, a housing including a housing space to house the motor and the gear, oil in a vertically lower region of the housing space, and an oil passage to lead the oil from the vertically lower region of the housing space to be fed to the motor. The housing space includes a motor chamber to house the motor; and a gear chamber to house the gear. The housing includes a partition to divide the motor chamber and the gear chamber. A bottom portion of the motor chamber is higher than a bottom portion of the gear chamber. A portion of the oil fed to the motor is in a vertically lower region of the motor chamber. A vertically lower region of the partition includes a partition opening to bring the gear chamber and the motor chamber into communication with each other. The partition opening is structured such that a rise in a liquid surface of the oil in the vertically lower region of the motor chamber causes an increase in an amount of transfer of the oil from the motor chamber to the gear chamber through the partition opening.