Power Transmission Device Floating Seals Oil Filtration

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Solution Overview

Problem

The existing power transmission devices require frequent oil replacement in the speed-reducer housing chamber to extend the lifetime of the wheel bearing, leading to complicated maintenance.

Innovation Solution

A power transmission device with a circulation passage for oil that includes an oil filter, connected to the lubrication space including the brake chamber and wheel bearings, and floating seals to prevent wear powder from mixing into the wheel bearing lubrication space, minimizing mechanical loss and extending the wheel bearing's lifetime without frequent oil replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the speed-reducer housing chamber and wheel bearing space are communicated to lubricate the wheel bearing using oil, then the wheel bearing can be lubricated, but wear powder generated by gear meshing mixes into the oil and shortens the wheel bearing lifetime

Engineering Contradiction:

Improvewheel bearing lifetimeVSAvoidwear powder contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the housing into separate chambers: a speed-reducer housing chamber for gears and a wheel bearing space for bearings. Floating seals create partitions between these chambers, preventing wear powder from the gear chamber from contaminating the bearing space while allowing independent oil circulation in each chamber.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts the harmful element (wear powder) from the lubrication system by isolating the gear chamber from the bearing space using floating seals. This separation removes the source of contamination from the wheel bearing lubrication environment.

Inventive Principle:

Principle #2Taking out (Extraction)

2Object-affected harmful factors

If floating seals are disposed between the brake chamber and wheel bearing space to divide the two spaces, then the wheel bearing is protected from brake dust, but the wheel bearing cannot be lubricated by oil from the speed-reducer housing chamber

Engineering Contradiction:

Improvebrake dust contaminationVSAvoidwheel bearing lubrication

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The floating seals act as intermediaries that selectively permit or block fluid passage. They separate the brake chamber from the wheel bearing space to prevent brake dust contamination while simultaneously allowing oil circulation from the speed-reducer housing chamber to reach the wheel bearing through controlled pathways.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If oil circulation is blocked between the speed-reducer housing chamber and wheel bearing space to prevent wear powder mixing, then the wheel bearing lifetime is extended, but the wheel bearing cannot be lubricated by oil from the speed-reducer housing chamber

Engineering Contradiction:

Improvewheel bearing lifetimeVSAvoidlubrication efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent segments the oil circulation system into independent loops: one for the speed-reducer housing chamber and another for the wheel bearing space. Floating seals create the segmentation barrier, while separate circulation passages allow each chamber to maintain its own oil circulation, ensuring both protection from wear powder and adequate lubrication.

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

The solution ensures constant purification and lubrication of the wheel bearings, preventing wear powder contamination and reducing maintenance complexity, thereby extending the wheel bearing's lifetime and minimizing mechanical loss in the gear speed reducer.

Implementation Method 1

a circulation passage for oil that includes an oil filter is connected to the lubrication space

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Implementation Method 2

floating seals are disposed between a lubrication space, including the brake chamber and the pair of wheel bearings, and the speed-reducer housing chamber

Methodology Applied

Scientific EffectPhysical barrier separation: Physical Containment

Implementation Method 3

a circulation passage for oil that includes an oil filter is connected to the lubrication space

Methodology Applied

Scientific EffectFluid circulation: Convection

Data Source

PatentUS10099550B2Power Transmission Device

Publication Date: 2018.10.16 KOMATSU LTD

AI summary

A power transmission device includes: an axle housing having a central hole where a drive shaft is penetrated; a wheel hub disposed in an outer portion of the axle housing via wheel bearings; a speed-reducer housing chamber provided in the wheel hub to cover an opening end portion of the axle housing; a gear speed reducer, formed inside the speed-reducer housing chamber, to decelerate a rotation of the drive shaft and transmit the rotation to the wheel hub; and a wet-type brake mechanism housed in a brake chamber formed between the axle housing and the wheel hub, and actuated such that braking is applied to a rotation of the wheel hub relative to the axle housing. Further, floating seals are disposed between a lubrication space and the speed-reducer housing chamber, and a circulation passage for oil that includes an oil filter is connected to the lubrication space.