Helical Gear Oil Level Control via Partitioned Chamber

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Solution Overview

Problem

Existing gear units in vehicles face challenges in stabilizing oil levels within the housing, leading to inconsistent lubrication and increased rotational resistance during vehicle operation, as high oil levels increase resistance while low levels result in unstable oil supply.

Innovation Solution

A gear unit design featuring a housing with a partition that creates two oil chambers, where a helical gear with angled teeth allows oil to flow from a higher oil chamber to a lower one during vehicle operation, adjusting the oil level based on operational state to minimize rotational resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the oil level in the housing is increased to ensure adequate lubrication, then lubrication stability is improved, but rotational resistance increases

Engineering Contradiction:

Improvelubrication stabilityVSAvoidrotational resistance

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The housing is divided into two separate oil chambers (first oil chamber and second oil chamber) by a partition, allowing independent oil level control in each chamber. This segmentation enables the system to maintain different oil levels in different regions, resolving the contradiction between adequate lubrication and reduced rotational resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The oil levels in the two chambers are made dynamic rather than static. During vehicle running, the oil level in the first oil chamber is maintained higher than in the second oil chamber through controlled oil flow. This dynamic oil level adjustment allows the system to adapt to operational conditions, providing stable lubrication where needed while minimizing rotational resistance in other areas.

Inventive Principle:

Principle #15Dynamics

2Loss of energy

If the oil level is decreased to reduce rotational resistance, then energy loss is reduced, but lubrication becomes unstable

Engineering Contradiction:

Improverotational resistanceVSAvoidlubrication stability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

By segmenting the single oil chamber into two separate chambers, the system can maintain low overall oil levels to reduce rotational resistance while ensuring adequate oil levels in specific areas (first oil chamber) where lubrication stability is critical. Each chamber can be optimized for its specific function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different oil levels are maintained in different locations within the housing. The first oil chamber maintains a higher oil level to ensure stable lubrication for specific components, while the second oil chamber maintains a lower level to minimize rotational resistance. This local differentiation of oil quality/level resolves the contradiction between energy efficiency and lubrication reliability.

Inventive Principle:

Principle #3Local quality

3Device complexity

If a single oil chamber is used, then device complexity is reduced, but oil level control precision is insufficient

Engineering Contradiction:

Improvechamber structureVSAvoidoil level control

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The partition dividing the housing into two oil chambers is a relatively simple structural element that can be manufactured and assembled with standard precision. This segmentation provides precise oil level control capability without requiring complex control systems, pumps, or sensors. The simplicity of the partition structure means that device complexity increases only minimally while gaining significant oil level control precision.

Inventive Principle:

Principle #1Segmentation

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 effectively varies oil levels to ensure smooth operation by reducing rotational resistance during vehicle use and maintaining adequate lubrication, thereby enhancing durability and reducing power loss.

Implementation Method 1

When the helical gear rotates in conjunction with the running of the vehicle, the oil flows from the second oil chamber into the first oil chamber

Methodology Applied

Scientific EffectHelical gear fluid drawing effect:

Data Source

PatentUS11466769B2Gear unit

Publication Date: 2022.10.11 SUBARU CORP

AI summary

A gear unit to be mounted in a vehicle includes a housing for storing oil, a partition disposed inside the housing, and a helical gear. The partition defines first and second oil chambers and has a through-hole allowing the first oil chamber to communicate with the second oil chamber. The helical gear disposed inside the first oil chamber rotates during running of the vehicle and has an angled tooth that draws inner and addendum circles defining a virtual circumferential plane. The through-hole coincides with a portion of the virtual circumferential plane in a direction parallel to a central axis of the helical gear. When the helical gear rotates in conjunction with the running of the vehicle, the oil flows from the second oil chamber into the first oil chamber so that an oil level of the first oil chamber becomes higher than that of the second oil chamber.