Twist Drill Segmented Helical Web for Friction and Fatigue

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Solution Overview

Problem

Existing drilling tools suffer from reduced fatigue resistance due to stress peaks caused by additional profiling for helical groove sections, leading to premature failure and impaired drilling effectiveness.

Innovation Solution

The introduction of multiple groove sections on the outer surface of the helical web, arranged transversely or at a non-negligible angle to the main spiral groove, which reduces friction and thermal stress without compromising fatigue strength, and are designed to extend along imaginary spiral paths with a smaller pitch than the main helical groove, enhancing drilling dust removal and air exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If additional helical groove sections are added to increase drilling effectiveness, then drilling performance is improved, but stress peaks are formed that lead to premature failure

Engineering Contradiction:
Improvedrilling effectivenessVSAvoidfatigue resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent divides the continuous helical groove into multiple separate groove sections along the helical path. These segmented groove sections reduce stress concentration compared to a continuous groove while maintaining the dust removal function. The segmentation principle allows the groove to be discontinuous yet still effective in transporting drilling dust away from the cutting zone.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different groove configurations at different locations along the helical path. The groove sections are strategically positioned and sized to provide enhanced dust removal where needed while maintaining structural integrity in critical areas. This local variation in groove characteristics optimizes both drilling performance and fatigue resistance.

Inventive Principle:
Principle #3Local quality

2Productivity

If the outer surface of the helical web is profiled with additional grooves, then drilling dust removal is enhanced, but the strength of the drilling tool is significantly impaired

Engineering Contradiction:
Improvedrilling dust removal efficiencyVSAvoidtool strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The continuous outer surface profiling is segmented into discrete groove sections. This segmentation reduces the total material removed from the helical web while still providing effective dust removal pathways. The discontinuous groove sections maintain structural strength better than a continuous groove would.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of profiling the entire outer surface with continuous grooves, the patent applies grooves partially along the helical path. This partial action is sufficient to achieve effective dust removal without excessively weakening the tool structure. The groove sections are positioned to provide maximum benefit with minimum material removal.

Inventive Principle:
Principle #16Partial or excessive action

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 significantly increases drilling effectiveness by reducing friction and thermal stress while maintaining or improving fatigue resistance, allowing for efficient drilling with reduced energy input and improved dust removal.

Implementation Method 1

The multiple groove sections in the outer surface of the helical web, which are transverse to the main helical groove, cause a significant reduction in friction between the workpiece and the drilling tool

Methodology Applied
Scientific EffectFriction reduction through geometric modification: Friction

Implementation Method 2

the drilling tool is subjected to far less thermal stress

Methodology Applied
Scientific EffectThermal stress reduction: Thermal Radiation

Data Source

PatentEP2116321B1Boring tool, in particular twist drill
Publication Date: 2014.01.08 IRWIN IND TOOL CO
  • EP2116321B1 patent drawingFigure 1~2

AI summary

The tool i.e. twist drill (1) has a cutting part (11) between a tool sided attachment end (3) and a tool sided blade end (17). A head spiral slots (13, 15) extend along the cutting part and is defined by constant spiral inclination. Spiral pin outer surfaces (21, 23) cylindrically or conically extend along the head spiral slots. The head spiral slots are defined by the cutting part. Multiple groove sections (27) are formed in the spiral pin outer surfaces and extend perpendicular to a direction of the head spiral slots inclination.