Dust Removal Duct Cross-Section and Rotation Alignment

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Solution Overview

Problem

The flow behavior of suction air in hand-held power tools is not optimal, particularly at the inlet opening of the dust removal connection, leading to suboptimal dust removal efficiency, especially in areas far from the inlet.

Innovation Solution

The dust removal duct is designed with a cross-section that increases in size further from the inlet opening, and the direction of tool rotation aligns with the air flow direction, enhancing suction power. Additionally, features like spiral ducts, air entrainment devices, and permeable seals improve airflow and dust extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the dust removal duct has a constant cross-section, then the structure is simple, but the suction effect is insufficient in areas far from the inlet opening

Engineering Contradiction:
Improvedust removal efficiencyVSAvoidduct structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The dust removal duct's cross-sectional area is varied along its length, increasing from the inlet opening toward the tool working area. This parameter change optimizes the suction effect by maintaining appropriate flow velocity while expanding the effective dust capture volume, thereby improving dust removal efficiency without requiring complex additional components

Inventive Principle:
Principle #35Parameter changes

2Power

If the tool rotation direction is opposite to the air flow direction, then the tool structure is simpler, but the suction power is reduced

Engineering Contradiction:
Improvesuction powerVSAvoidflow guidance structure
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The rotational direction of the tool is changed to match the air flow direction in the dust removal duct. This parameter change creates a synergistic effect where the tool rotation reinforces the suction flow, generating additional centrifugal force that enhances dust particle separation and improves overall suction power

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 configuration ensures optimal suction and dust removal efficiency across the tool space, including areas far from the inlet, by aligning flow directions and increasing cross-sectional area, resulting in improved dust extraction performance.

Implementation Method 1

the flow cross section is smaller at a greater distance from the inlet opening of the dust discharge connection... the flow cross section can increase in stages... the flow cross section increases essentially continuously

Methodology Applied
Scientific EffectFlow cross section increase:

Implementation Method 2

A direction of rotation of the tool for machining the work object and a direction of flow of the air in the dust removal duct advantageously correspond. The direction of rotation and the direction of flow run in the same direction, for example. As a result, a flow intensification or even flow generation is achieved.

Methodology Applied
Scientific EffectFlow intensification:

Implementation Method 3

The dust removal duct expediently runs spirally, i.e. it has a spiral shape. For example, the dust removal channel runs around a work spindle on which the tool is arranged.

Methodology Applied
Scientific EffectSpiral flow:

Data Source

PatentEP2163356B1Hand-held power tool with a covering cap and a dust removal connection
Publication Date: 2011.11.02 PROTOOL
  • EP2163356B1 patent drawingFigure 1a~1b
  • EP2163356B1 patent drawingFigure 2a~2c
  • EP2163356B1 patent drawingFigure 3a~3b

AI summary

The hand machine tool (10) has a tool holder rotary operated by a driving motor (13) for a machining side for abrasive or cutting work object machining with a tool and a cover plate (25) with a tool area for supporting the tool for partial covering of the tool. A dust removal channel is guided to an inlet of a dust removal connection. The dust removal channel is formed between the tool and a wall of the tool area.