Drill Bit Arcuate Cutting Edge Geometry for Friction Reduction

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Solution Overview

Problem

Conventional rock drilling tools lack comprehensive optimization in terms of destruction capacity, friction, and material consumption, leading to reduced resilience and service life despite increased material usage.

Innovation Solution

The drilling tool features cutting edges with an arcuate course that inhibits radial movement of drill cuttings, enhancing their entrainment and removal through discharge grooves, reducing friction losses, and a cutting body geometry that increases material volume in high-load areas and reduces it in low-load areas, ensuring improved resilience and service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If drill cuttings are allowed to move radially outward, then material removal is simplified, but friction losses increase and service life decreases

Engineering Contradiction:
Improvefriction lossesVSAvoidcutting edge geometry
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The cutting edge is designed with an arcuate course instead of a straight line, creating a curved geometry that actively manages drill cuttings. The arcuate shape with radius larger than the nominal radius of the cutting body guides cuttings along a curved path, preventing radial escape and reducing friction between cuttings and borehole wall.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The cutting edge features a concave section with specific geometric properties (arcuate course) localized at the critical region where cuttings are generated and managed. This localized geometric modification creates a sickle-shaped profile that specifically addresses the friction problem without redesigning the entire cutting body.

Inventive Principle:
Principle #3Local quality

2Reliability

If cutting body volume is increased to improve resilience, then load capacity increases, but material consumption increases

Engineering Contradiction:
Improveservice lifeVSAvoidhard metal volume
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The cutting body is designed with non-uniform thickness, having maximum thickness at the cutting edge and decreasing thickness toward the rear. This localized material distribution places material strategically where it is most needed for resilience and load bearing, rather than uniformly throughout the entire cutting body.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cutting edge geometry extends into the longitudinal dimension with an arcuate course that projects forward in the direction of rotation. This creates a three-dimensional sickle-shaped profile that increases effective cutting edge volume and resilience without proportionally increasing overall material consumption.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Loss of energy

If arcuate section radius is increased to improve cuttings entrainment, then friction losses reduce, but excessive cuttings retention occurs

Engineering Contradiction:
Improvefriction lossesVSAvoidmaterial removal rate
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The arcuate section uses a specific radius parameter that is larger than the nominal radius of the cutting body, creating an optimized geometric parameter for cuttings management. This parameter change balances the competing requirements of cuttings retention for friction reduction versus timely discharge for productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2481505B1Drill bit, in particular for drilling and/or cutting device
Publication Date: 2014.06.18 ROBERT BOSCH GMBH
  • EP2481505B1 patent drawingFigure 1a~1b
  • EP2481505B1 patent drawingFigure 2
  • EP2481505B1 patent drawingFigure 3

AI summary

The tool (1) has a cutting body (6) designed as a solid carbide head and radially projecting over a drill head (5). The cutting body has two blades with blade edges. The blades extend radially outward from a blade tip. The blade edges of the cutting body exhibit sections between the blade tip and lateral surfaces that connect side surfaces. The sections are provided with a curved profile that brakes a radially outward directed movement of drill cuttings. The sections are viewed in a direction of a longitudinal axis (L1) of the tool.