Machine Tool Vibration Sensor Layout for Abnormality Localization

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Solution Overview

Problem

Existing abnormality detection devices for machine tools face challenges in specifying the exact item whose machining accuracy is compromised due to abnormal vibrations, making it difficult to diagnose and address machining issues effectively.

Innovation Solution

An abnormality detection device equipped with multiple vibration sensors mounted at specific positions on a machine tool, which uses a determination portion to analyze vibration data and correlate sensor positions with machining accuracy issues, allowing for easy identification of affected items based on stored memory data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex calculation is used to diagnose machining condition from abnormal machining operation, then abnormality detection capability is improved, but ease of specifying predetermined item whose machining accuracy lowers deteriorates

Engineering Contradiction:
Improveabnormality detection capabilityVSAvoidease of specifying predetermined item
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent segments the vibration detection system into multiple vibration sensors positioned at specific locations (spindle, tool, workpiece). Each sensor independently detects vibrations, and the determination portion specifies the affected machining item based on which sensor detected the abnormality, eliminating complex calculations while maintaining diagnostic capability.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple vibration sensors are mounted at plurality of positions, then measurement precision of vibration source location is improved, but device complexity increases

Engineering Contradiction:
Improvevibration source location precisionVSAvoidsensor arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by placing vibration sensors at specific critical locations (spindle, tool, workpiece) where vibrations originate. Each position monitors specific machining aspects, enabling precise localization of vibration sources without requiring comprehensive coverage that would increase complexity.

Inventive Principle:
Principle #3Local quality

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

Enables precise specification of items with lowered machining accuracy, facilitating the determination of associated machining operation abnormalities and improving diagnostic efficiency.

Implementation Method 1

a plurality of vibration sensors mounted on a body of the machine tool at a plurality of positions

Methodology Applied
Scientific EffectVibration detection: Vibration

Data Source

PatentEP3670072B1Abnormality detection device and machine tool including abnormality detection device
Publication Date: 2023.05.10 CITIZEN WATCH CO LTD
  • EP3670072B1 patent drawingFigure 1
  • EP3670072B1 patent drawingFigure 2~3
  • EP3670072B1 patent drawingFigure 4

AI summary

In an abnormality detection device, in order to specify a vibration sensor that has detected abnormal vibration, and easily detect a predetermined item whose machining accuracy lowers as an operation condition of a machine tool based on a mounted position of the specified sensor, an abnormality detection device (10) of a machine tool (1) includes a plurality of vibration sensors (11 to 20) mounted on a body of the machine tool (1) at a plurality of positions; and a determination portion (32) that determines an operation condition of the machine tool based on vibration information detected by the vibration sensors (11 to 20). The abnormality detection device (10) detects abnormality of the machine tool (1) according to determination information of the determination portion (43). The determination portion (34) specifies a predetermined item whose machining accuracy lowers based on the mounted position of the vibration sensor (11 to 20) that has detected abnormal vibration.