Rolling Guide Diagnosis Using Load-Path Cycle Signal Sampling

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Solution Overview

Problem

The existing state diagnosis systems for rolling guide devices, which rely on sensors to detect physical quantities like sound, vibration, or acoustic emission, face challenges in processing signals due to the unique endless circulation path configuration of rolling elements, making it difficult to determine abnormalities effectively.

Innovation Solution

A state diagnosis system that includes a sensor to detect physical quantities, a signal processing unit to generate analysis data through root mean square processing, and a determination processing unit to compare the data with threshold values, ensuring the data collection time period aligns with the cycle at which rolling elements enter the load path, allowing for accurate recognition of the rolling guide device's state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor detects physical quantities (sound, vibration, acoustic emission) to diagnose the rolling guide device, then the ability to detect abnormalities is improved, but the signal processing becomes complex due to the endless circulation path configuration of rolling elements

Engineering Contradiction:
Improveabnormality detection accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the continuous signal into discrete measurement periods corresponding to each rolling element's passage through the load zone. By dividing the measurement into discrete segments aligned with rolling element cycles, the complex continuous signal becomes manageable discrete data points that can be compared against thresholds, reducing processing complexity while maintaining detection accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs periodic measurement at intervals corresponding to the passage of each rolling element through the load zone. This periodic sampling synchronizes with the natural cycle of the rolling elements, transforming the complex continuous signal into a series of periodic measurements that are easier to analyze and compare, thereby reducing signal processing complexity while preserving abnormality detection capability.

Inventive Principle:
Principle #19Periodic action

2Reliability

If continuous monitoring of the rolling guide device is implemented using sensors, then the reliability of operation is improved, but the difficulty of detecting and measuring the state accurately worsens due to signal variations from rolling elements entering and exiting the load path

Engineering Contradiction:
Improveoperation reliabilityVSAvoidstate detection difficulty
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent performs preliminary processing of the sensor signal by comparing each measurement against a predetermined threshold before making a diagnosis determination. This preliminary filtering action eliminates the need to process the entire complex continuous signal, reducing the measurement difficulty while maintaining reliable detection of abnormal states through simple threshold comparison.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If the data collection time period is set to capture the cycle of rolling elements entering the load path, then the measurement precision is improved, but the loss of time for diagnosis increases

Engineering Contradiction:
Improvestate recognition accuracyVSAvoiddiagnosis time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent collects signal data over a period that captures at least one complete cycle of rolling element passage through the load zone, which may be longer than the minimum necessary to detect an anomaly. This excessive collection period ensures that the complete state cycle is captured, improving measurement precision by ensuring all relevant signal variations are included, while the subsequent threshold comparison quickly determines the result, minimizing actual diagnosis time.

Inventive Principle:
Principle #16Partial or excessive action

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 approach enables appropriate recognition of the rolling surface and lubrication state of the rolling guide device, effectively determining normal operation or abnormalities, thus maintaining optimal performance and extending the device's lifespan.

Implementation Method 1

a sensor configured to detect a physical quantity exhibited when the moving member is moving along the track member

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

detect sound, vibration, or acoustic emission generated at the time of a rotational operation

Methodology Applied
Scientific EffectAcoustic emission: Acoustic Emission

Implementation Method 3

the output signal taken in from the sensor in the data collection time period T is subjected to root mean square processing to become analysis data

Methodology Applied
Scientific EffectRoot mean square processing:

Data Source

PatentEP3543673B1Condition diagnosing system for rolling guide device
Publication Date: 2021.08.18 THK CO LTD
  • EP3543673B1 patent drawingFigure 1~2
  • EP3543673B1 patent drawingFigure 3
  • EP3543673B1 patent drawingFigure 4(a)~5

AI summary

Provided is a state diagnosis system, which is applied to a rolling guide device in which a movihg member (2) including an endless circulation path (5) for rolling elements (6) is freely movable along a track member (1), and which is configured to appropriately recognize a state of a rolling surface of the track member (1). The state diagnosis system includes: a sensor (35) configured to detect a physical quantity exhibited when the moving member (2) is moving along the track member (1); a signal processing unit configured to process an output signal from the sensor to output analysis data; and a determination processing unit configured to compare the analysis data with threshold value data to determine whether or not the rolling guide device has an abnormality. Further, when a cycle at which each of the rolling elements (6), which moves back and forth in the endless circulation path (5), enters a load path (50) from a no-load path is represented by t, a data collection time period T, for which the signal processing unit takes in the output signal from the sensor (35), is set to satisfy T≥t.