Gear Lubricant Additive Tracking for Early Deterioration Diagnosis

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Solution Overview

Problem

Existing methods for predicting failure in mechanical apparatuses, such as industrial robots, are inaccurate as they rely on detecting abnormal wear through iron powder content in lubricating grease, failing to catch the trend of deterioration before abnormal wear occurs.

Innovation Solution

A deterioration diagnosis apparatus that stores the trend of additive consumption rate in lubricant and determines the period for the consumption rate to reach a threshold, using a linear approximation and functions of motor electric-current instruction values and grease temperature to predict the remaining service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If iron powder content in lubricating grease is measured to predict failure, then failure prediction capability is provided, but the prediction accuracy is insufficient because it only detects abnormal wear after it occurs

Engineering Contradiction:

Improvefailure prediction capabilityVSAvoidprediction accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

Instead of measuring iron powder content to detect abnormal wear after it occurs, the invention inverts the approach by measuring additive consumption rate to detect deterioration trends before abnormal wear occurs. This allows prediction of remaining service life by monitoring how quickly additives are consumed from the lubricant, providing earlier and more accurate failure prediction.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention changes the measurement parameter from iron powder content (which indicates abnormal wear after occurrence) to additive consumption rate (which indicates deterioration trend before abnormal wear). By using linear approximation of the consumption rate trend and relating it to service life, the system achieves more precise prediction of when failure will occur.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If vibration and electric current monitoring is used to detect abnormal conditions, then online monitoring capability is provided, but the monitoring is insufficient because abnormalities are detected only when parts are already near failure

Engineering Contradiction:

Improveonline monitoring capabilityVSAvoidtime for preventive maintenance

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The invention performs preliminary detection of deterioration trends by monitoring additive consumption rate before abnormal wear occurs. By establishing a baseline consumption rate and detecting deviations from this baseline, the system can schedule preventive maintenance in advance, rather than waiting for vibrations or current abnormalities that indicate near-failure conditions.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12365087B2Deterioration diagnosis apparatus for diagnosing deterioration in a mechanical apparatus, and deterioration diagnosis method for diagnosing deterioration in a mechanical apparatus

Publication Date: 2025.07.22 KAWASAKI JUKOGYO KK

AI summary

A deterioration diagnosis apparatus is for a mechanical apparatus including a power transmission mechanism that transmits power via a gear. The deterioration diagnosis apparatus includes: a storing unit that stores, in advance, a trend of change along with the operation of the mechanical apparatus, in consumption rate of an additive contained in lubricant used for the gear; and a determination unit that determines the period to be taken for the consumption rate of the additive to reach a predetermined value, based on the trend of change in the consumption rate of the additive.