Sensorized Cutting Tool Shaft for Strain and Acceleration Sensing

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Solution Overview

Problem

Current cutting tools lack the capability to obtain detailed and useful data during machining, limiting the accuracy and efficiency of state assessment.

Innovation Solution

A cutting tool design featuring a shaft with a sensor device that includes multiple sensors arranged on a 4n-sided polygon region, allowing for the detection of strain and acceleration, with a wireless communication unit to transmit data, enhancing data acquisition and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple sensors are arranged on the shaft to detect physical quantities, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The shaft is segmented into multiple measurement regions with sensors arranged at different positions (first, second, third, and fourth regions). Each region has sensors oriented at specific angles (0°, 45°, 90°, 135°) to detect strain in different directions. This segmentation allows comprehensive measurement of complex stress states while organizing the sensor system in a structured manner that manages complexity through systematic spatial distribution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from single-point measurement to multi-dimensional measurement by arranging sensors in multiple regions around the shaft's circumference at different angular positions. This spatial dimensionality enables detection of strain in multiple directions simultaneously, capturing the full complexity of stress states during machining operations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If sensor device surrounds the shaft to detect strain and acceleration, then reliability of state assessment is improved, but manufacturing precision requirements increase

Engineering Contradiction:
ImprovereliabilityVSAvoidmanufacturing precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs asymmetric sensor arrangement where sensors are positioned at specific non-uniform intervals around the shaft (first region at 0°, second region at 45°, third region at 90°, fourth region at 135°). This asymmetric configuration optimizes the detection of complex stress states that occur during machining, allowing reliable state assessment while accommodating practical manufacturing tolerances through strategic sensor placement rather than requiring uniform precision throughout.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces a processing unit that acts as an intermediary between the multiple sensors and the final state assessment. This processing unit receives signals from all sensor regions, performs integrated analysis of the combined data, and generates the overall state assessment. The intermediary processing unit consolidates information from multiple precision-critical components, reducing the impact of individual manufacturing variations on overall system reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 cutting tool effectively obtains more useful data, improving the assessment of its state during machining by accurately measuring strain and acceleration, thereby enhancing machining precision and efficiency.

Implementation Method 1

a sensor module including a plurality of first sensors configured to detect a first physical quantity of the shaft

Methodology Applied
Scientific EffectStrain detection: Piezoresistive Effect

Implementation Method 2

a sensor module including a plurality of first sensors configured to detect a first physical quantity of the shaft

Methodology Applied
Scientific EffectAcceleration detection: Accelerometer

Data Source

PatentEP4260977B1Cutting tool
Publication Date: 2025.01.01 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP4260977B1 patent drawingFigure 1
  • EP4260977B1 patent drawingFigure 2
  • EP4260977B1 patent drawingFigure 3

AI summary

A cutting tool includes a shaft extending along a rotation axis and having a first end portion and a second end portion, and a sensor device disposed in such a manner as to surround a portion of the shaft in a longitudinal direction of the shaft. The cutting tool is configured to cut a workpiece by rotating around the rotation axis of the shaft. The sensor device includes a sensor module including a plurality of first sensors configured to detect a first physical quantity of the shaft, a substrate electrically connected to the first sensors, and a wireless communication unit electrically connected to the substrate and configured to transmit a signal including information of the first physical quantity detected by the first sensors to outside and a housing accommodating the sensor module. A region of the shaft surrounded by the sensor device includes a first region having a shape of a 4n-sided polygon when viewed from a direction in which the rotation axis extends. The n is a natural number of two or more. When viewed from the direction in which the rotation axis extends, the plurality of first sensors are arranged on at least two of outer peripheral surfaces of the first region, each of the outer peripheral surfaces of the first region corresponding to one of sides of the 4n-sided polygon, perpendicular lines of the at least two outer peripheral surfaces passing through the rotation axis and intersecting each other at 90 degrees.