Torque Sensor in Power Tool Handle for Vibration Isolation

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Solution Overview

Problem

Existing power tools with torque sensors installed on the transmission mechanism suffer from issues such as broken wires, contact failures, and reduced accuracy due to vibration and deformation, affecting torque detection reliability and precision.

Innovation Solution

The torque sensor is positioned in the handle of the power tool housing, perpendicular to the power device, avoiding rotation and vibration, and utilizing a strain gauge to detect torque through deformation of a torque post fixed to the bushing, ensuring accurate torque detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the torque sensor is installed on the transmission mechanism, then the torque sensor can detect torque during operation, but the sensor rotates with the power device causing broken wires, contact failures, and reduced reliability

Engineering Contradiction:
Improvetorque detection reliabilityVSAvoidrotation-induced wire breakage and contact failure
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The torque sensor is extracted from the rotating transmission mechanism and relocated to the stationary handle portion of the power tool. This separation removes the sensor from the harmful rotating environment, eliminating wire breakage and contact failure issues while preserving torque detection capability through the torque post that transmits torque from the rotating bushing to the stationary sensor.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If the torque sensor is installed on the transmission mechanism, then torque detection is enabled, but vibration and deformation of the transmission mechanism reduce measurement accuracy

Engineering Contradiction:
Improvetorque detection accuracyVSAvoidvibration and deformation of transmission mechanism
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The torque sensor is removed from the vibrating transmission mechanism and positioned in the stationary handle. The torque post acts as a transmission element that conveys torque from the rotating bushing through the stationary platform, isolating the sensor from vibration and deformation while maintaining accurate torque measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The torque post serves as an intermediary element between the rotating bushing and the stationary torque sensor. It transmits torque forces from the rotating component to the sensor while being supported by the stationary platform, thereby isolating the sensor from vibration and deformation effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the torque sensor is positioned in the handle perpendicular to the power device, then the sensor is isolated from vibration and rotation, but the structural configuration becomes more complex

Engineering Contradiction:
Improvesensor isolation from vibration and rotationVSAvoidtorque post and platform structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The torque post and platform structure serve multiple functions: they provide structural support for the handle, transmit torque forces from the rotating bushing to the sensor, and isolate the sensor from vibration and rotation. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in structural complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration prevents issues like broken wires and contact failures, enhances assembly convenience, and provides accurate torque values by isolating the sensor from power body vibrations, thus improving detection reliability.

Implementation Method 1

utilizing a strain gauge to detect torque through deformation of a torque post fixed to the bushing

Methodology Applied
Scientific EffectStrain gauge deformation detection: Piezoresistive Effect

Data Source

PatentEP4353418B1Torque sensing arrangement of power tool
Publication Date: 2026.03.18 MATATAKITOYO TOOL
  • EP4353418B1 patent drawingFigure 1
  • EP4353418B1 patent drawingFigure 2
  • EP4353418B1 patent drawingFigure 3

AI summary

A power tool includes a housing (10), a power device (20), a bearing set (30), a torque post (40) and a torque sensor (50). The housing (10) includes a main body (11) and a handle (12) perpendicularly connected to one side of the main body (11). The power device (20) is disposed in the main body (11) and includes a power body (21) and a bushing (22) adapted to sheathe the power body (21). The bearing set (30) is arranged between the bushing (22) and the housing (10). The power body (21) may rotate relative to the housing (10). The torque post (40) is disposed in the handle (12) and abuts against the bushing (22). The torque post (40) is arranged perpendicularly to the power body (21). The torque sensor (50) is disposed on the torque post (40).