Electric Tool Torque Calibration Using an Inspection Device
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Solution Overview
Problem
The reliability of tightening torque values measured by electric tools is not adequately improved in existing systems, as they lack effective methods for accurate calibration and condition monitoring.
Innovation Solution
An electric tool system that includes a tightening unit, a sensor to measure torque, and an inspection device with a measuring unit, along with an association processor to associate and calibrate the torque values, ensuring accurate measurement and adjustment of the tightening torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is used to measure tightening torque in the electric tool, then torque measurement capability is provided, but measurement precision and reliability are insufficient without external calibration
Solution Approach 1:
An inspection device is introduced as an intermediary calibration tool that applies known tightening forces to the electric tool. This external reference device enables the sensor to be calibrated against accurate reference values, thereby improving measurement precision and reliability without modifying the sensor itself.
Solution Approach 2:
The system changes the operational parameters of the sensor by applying multiple different tightening forces (first tightening force, second tightening force, etc.) during calibration. By measuring the sensor output across multiple parameter points and establishing a calibration curve, the system improves measurement accuracy across the entire operating range.
2Measurement precision
If an inspection device with measuring unit is added to measure tightening force, then calibration capability is improved, but device complexity increases
Solution Approach 1:
The inspection device is designed to integrate multiple functions: it serves as both a calibration device and a measurement device. The measuring unit that measures tightening force is also used to provide calibration data, merging reference measurement and calibration functions into a single device to reduce overall system complexity.
Solution Approach 2:
The electric tool performs self-calibration by using its own sensor to measure the tightening forces applied by the inspection device. The tool's controller automatically processes the calibration data and adjusts its measurement parameters, enabling self-service calibration without requiring external calibration equipment or manual intervention.
3Measurement precision
If multiple tightening forces are applied during calibration, then calibration accuracy is improved, but measurement time and productivity are reduced
Solution Approach 1:
The system applies multiple tightening forces in advance during the calibration process to establish a comprehensive calibration curve before actual measurement operations begin. This preliminary multi-point calibration ensures high accuracy across the entire measurement range, preventing the need for repeated calibrations during use.
Solution Approach 2:
The calibration process is designed to be universal across different operating conditions. By calibrating at multiple tightening force levels, a single calibration procedure establishes measurement accuracy for the entire operating range of the tool, making the calibration process universally applicable rather than requiring separate calibrations for different torque levels.
Data Source
AI summary
An electric tool system includes an electric tool and an inspection device. The electric tool includes: a tightening unit configured to tighten a workpiece onto an attaching target by driving force of a drive source; and a sensor configured to measure a tightening torque provided by the tightening unit. The inspection device includes a measuring unit configured to measure tightening force applied from the tightening unit. The electric tool system further includes an association processor configured to associate a first torque measured value with a second torque measured value. The first torque measured value corresponds to a measurement result by the sensor. The second torque measured value corresponds to a measurement result by the measuring unit.