Damping Elements in Hammer Drill Sleeve Mounting

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Solution Overview

Problem

Existing motor-driven power tools with rotary hammer mode experience operational discomfort due to axial forces transmitted from the hammer mechanism to the drill sleeve and subsequently to the user, leading to vibration and reduced efficiency.

Innovation Solution

The drill sleeve is axially supported by flexible, elastically deformable damping elements on both sides, which absorb periodic axial forces and provide prestress in opposite directions, ensuring a play-free mounting and reduced vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the drill sleeve is rigidly mounted in the machine housing, then structural stability is maintained, but axial forces from the hammer mechanism cause vibration and operational discomfort

Engineering Contradiction:
Improveoperational smoothnessVSAvoidvibration
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A damping element is introduced as an intermediary component between the drill sleeve and the machine housing. This damping element absorbs and dissipates the periodic axial forces generated by the hammer mechanism, preventing direct transmission of vibrations to the user while maintaining the structural connection between components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mounting system transitions from a rigid connection to a flexible connection by changing the mechanical properties of the interface. The damping element provides elastic deformation that allows the drill sleeve to move slightly in response to axial forces, converting harmful vibrational energy into elastic potential energy and heat.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If damping elements are added to reduce axial forces, then vibration is reduced, but device complexity increases

Engineering Contradiction:
Improveoperational smoothnessVSAvoidstructure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The damping element is implemented as a flexible component that can be integrated into the existing mounting structure. This flexible element provides vibration damping while maintaining a relatively simple overall structure, avoiding the need for complex active control systems or multiple separate components.

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If the drill sleeve is held without axial play, then positioning precision is improved, but the ability to absorb axial forces is reduced

Engineering Contradiction:
Improvepositioning precisionVSAvoidforce transmission
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The damping element changes the mechanical parameters of the mounting interface by providing controlled elasticity. This allows the drill sleeve to maintain precise positioning while the elastic material absorbs axial forces through deformation, preventing force transmission to the user.

Inventive Principle:
Principle #35Parameter changes

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 enhances operational smoothness and efficiency by minimizing vibrations and compensating for production tolerances, resulting in higher single impact energy values and reduced power loss across all operating modes.

Implementation Method 1

flexible, elastically deformable damping element

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the drill sleeve vibrates to a much lesser extent than is the case with known hammer drills

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 3

the damping elements exert a prestress directed in opposite directions on the drill sleeve, so that it is held without axial play in relation to the machine housing

Methodology Applied
Scientific EffectPrestress: Stress Relaxation

Data Source

PatentEP2314420B1Motor driven tool device with hammer drill operation mode
Publication Date: 2012.05.09 METABOWERKE
  • EP2314420B1 patent drawingFigure 1
  • EP2314420B1 patent drawingFigure 2
  • EP2314420B1 patent drawingFigure 3

AI summary

The device has an output strand (6) comprising a boring sleeve (10) and a forge. The boring sleeve is radially supported in a rotatable manner around a longitudinal axis in relation to a machine housing (33). The boring sleeve is axially supported via a roller bearing arrangement for receiving of axial forces that are induced at a tool. The boring sleeve is held in the machine housing at both axial sides by axial acting soft and elastic deformable damping elements (34, 36), which are designed in a circular disk type. The damping elements are made of plastic material/polyurethane foam.