Percussive Rock Drill Bit Flushing Grooves

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Solution Overview

Problem

Conventional percussive rock drill bits have inefficient flushing grooves that hinder axially rearward fluid flow and are prone to damage from rock contact, reducing drilling performance and penetration rate.

Innovation Solution

The design features radially outward and axially rearward flushing grooves with a convex flow path and recessed aperture edges to minimize friction and maintain fluid flow efficiency, preventing damage and enhancing the transport of rock debris.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional flushing grooves are used with straight transitions from front face to shank, then manufacturing is simpler, but fluid flow efficiency deteriorates due to ridges and sharp angled transitions that perturb flow

Engineering Contradiction:

Improvedrilling penetration rateVSAvoidgroove geometry complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The flushing grooves are designed with curved flow paths that eliminate sharp angles and ridges. The grooves feature smooth transitions with rounded corners and continuous curvature throughout their length from front face to shank, optimizing fluid flow without requiring complex manufacturing processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Productivity

If the axially forwardmost part of flushing fluid passageway is positioned at the front face for optimal flushing, then fluid delivery to rock face is maximized, but the passageway becomes damaged due to contact with rock

Engineering Contradiction:

Improvefluid delivery efficiencyVSAvoidpassageway durability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The flushing grooves are pre-positioned to emerge at the front face at an optimal location that delivers fluid efficiently to the rock face while maintaining sufficient distance from direct rock contact zones. The groove emergence points are strategically located to receive fluid before it contacts the rock, preventing damage to the passageway structure.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If flushing grooves have straight radial transitions, then manufacturing is easier, but fluid flow efficiency deteriorates due to sharp angled transitions

Engineering Contradiction:

Improvegroove fabrication simplicityVSAvoidaxially rearward flushing efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The grooves incorporate continuous curved transitions throughout their length, replacing all straight radial segments with smooth arcs. This ensures optimal fluid flow while maintaining manufacturability through standard machining operations that can produce continuous curved surfaces.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Ease of manufacture

If conventional groove orientations are used, then alignment is simpler, but axially rearward flushing efficiency deteriorates

Engineering Contradiction:

Improvegroove alignment simplicityVSAvoiddebris transport efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The flushing grooves are oriented at specific asymmetric angles relative to the bit axis, with each groove positioned and angled to optimize the axial rearward flow path. The grooves emerge at the front face at predetermined angles that maximize fluid velocity in the axial direction while maintaining straightforward alignment procedures.

Inventive Principle:

Principle #4Asymmetry

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 optimizes the axially rearward flushing of rock debris, increasing drilling penetration rate and reducing drilling time by ensuring unhindered fluid flow and protecting the fluid passageways from rock contact damage.

Implementation Method 1

a plurality of fluid passageways that extend from a central bore of the bit to emerge at flushing grooves at the front face

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

the fluid flow path length within the grooves (from the axially forwardmost region of the head to the radially outer perimeter of the head at the region of the shank) is devoid of ridges or sharp angled transitions that would otherwise perturb the fluid flow

Methodology Applied

Scientific EffectFluid flow optimization:

Implementation Method 3

the annular leading edge that defines the exit aperture (in the vicinity of the front face) of the flushing passageway is positioned at the trough region of each respective flushing groove such that this aperture edge is positioned axially rearward from the front face and is accordingly set back from the rock face during cutting to avoid frictional contact damage with the rock

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS10626680B2Percussive rock drill bit with flushing grooves

Publication Date: 2020.04.21 SANDVIK INTELLECTUAL PROPERTY AB

AI summary

A percussive rock drill bit has a head and a shank in which a plurality of flushing grooves extend radially outward and axially rearward from a front face. The flushing grooves are configured to optimize the axially rearward flow of rock particles and fines entrained in the flushing fluid. In particular, each groove is generally convex relative to a longitudinal axis of the drill bit and is declined continuously relative to the axis from a first groove end to a second groove end.