Active Torsional Vibration Damping in Hand-Held Power Tools

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Solution Overview

Problem

Hand-held processing devices, such as power-driven tools, often cause significant vibration that leads to user discomfort, particularly in the wrist, due to inadequate damping mechanisms, which affects the overall comfort and efficiency of operation.

Innovation Solution

The integration of an electrically controllable vibration damping device within the hand-held processing device, which automatically adjusts to dampen or avoid vibration excitation during operation, utilizing a drive motor system and a shaft capable of torsional vibration, thereby reducing user strain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a hand-held processing device is operated without adequate vibration damping, then the device structure remains simple and energy consumption is low, but user comfort deteriorates due to significant vibration and wrist strain

Engineering Contradiction:
Improveuser comfortVSAvoiddamping mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces passive mechanical damping elements with an active electromechanical vibration damping device that uses a motor system to generate counter-vibrations. This substitution transforms the damping approach from static mechanical structures to dynamic electromechanical systems, enabling active control of vibrations to improve user comfort.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The vibration damping device dynamically adjusts its operation based on real-time vibration detection. The system continuously monitors vibration levels and actively modifies damping forces to counteract detected vibrations, transforming the damping mechanism from a static passive element to a dynamic active system that adapts to changing operating conditions.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If an active vibration damping device is integrated into the hand-held processing device, then user comfort improves through reduced vibration, but energy consumption increases due to the additional motor system

Engineering Contradiction:
Improveuser comfortVSAvoidenergy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The system incorporates vibration detection sensors that continuously monitor vibration levels and feed this information back to the control system. The control system processes this feedback and adjusts the damping device's motor output accordingly, creating a closed-loop control system that optimizes energy consumption by applying damping forces only when and where vibrations are detected.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The damping device dynamically changes its operational parameters including motor power output, vibration frequency, and damping force intensity based on real-time detection of vibration conditions. This parameter adaptation allows the system to consume minimal energy during low-vibration operations while providing full damping capability when needed.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If passive damping elements are used in the hand-held processing device, then the device structure remains simple, but vibration reduction effectiveness is insufficient leading to user discomfort

Engineering Contradiction:
Improvevibration reduction effectivenessVSAvoiddamping device structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces passive mechanical damping elements with an active electromechanical vibration damping device that uses a motor system to generate counter-vibrations. This substitution transforms the damping approach from static mechanical structures to dynamic electromechanical systems, enabling active control of vibrations to improve user comfort.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The vibration damping system is self-regulating through its feedback mechanism. The detection sensors automatically identify vibration patterns and the control system autonomously adjusts damping forces without requiring external intervention or complex mechanical pre-adjustment mechanisms, simplifying the overall device structure while maintaining high effectiveness.

Inventive Principle:
Principle #25Self-service

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 solution significantly enhances user comfort by minimizing vibration-induced strain, allowing for more efficient and comfortable operation of hand-held processing devices, especially in tools like brush cutters and edge cutters, by actively damping or avoiding vibration excitation.

Implementation Method 1

a vibration damping device (6), in particular electrically controllable, in particular electrically, in particular electronically, having at least one actuator (10), in particular electric, in particular electronically controllable, which is designed or configured at least for the, in particular indirect and/or direct, damping and/or, in particular, even for the, in particular indirect and/or direct, reduction, in particular prevention, of the excitation, in particular non-excitation, of at least one vibration

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

a drive motor system (4), in particular electrically controllable, in particular electrically, in particular electronically, which is designed or configured for the drive, in particular rotary or rotational movement, of the shaft (3)

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP3942916B1Method for operating a hand-held processing device and hand-held processing device
Publication Date: 2024.09.04 ANDREAS STIHL AG & CO KG
  • EP3942916B1 patent drawingFigure 1
  • EP3942916B1 patent drawingFigure 2
  • EP3942916B1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a hand-held machining device (1), wherein the machining device (1) comprises: - a movable machining tool assembly (2), - a shaft (3), wherein the shaft (3) is configured for moving the machining tool assembly (2), - a drive motor system (4), wherein the drive motor system (4) is configured for driving the shaft (3), - wherein the machining tool assembly (2), the shaft (3) and the drive motor system (4) at least partially form at least a part of a torsional vibration-capable system (5), and - a controllable vibration damping device (6), wherein the vibration damping device (6) is configured at least for damping and/or reducing the excitation of at least one vibration (RS) of the torsional vibration-capable system (5) and/or is excitable by the torsional vibration-capable system (5).- wherein the method comprises the steps of: a) operating the drive motor system (4) to drive the shaft (3) to move the machining tool assembly (2), and b) controlling the vibration damping device (6) during operation such that the vibration (RS) is at least damped and/or excitation of the vibration (RS) is reduced.