Asymmetric Drill Head Design for Bore Dust Discharge
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Solution Overview
Problem
Existing rock drill heads with multiple cutting edges experience high friction and heat generation, leading to increased wear and reduced drill power due to inefficient bore dust discharge, which impairs hole quality and drill feed rate.
Innovation Solution
A hard metal drill head design with two main bore dust discharge sectors greater than 120° and an asymmetrical configuration to improve bore dust discharge, reducing friction and heat while maintaining hole quality and increasing drill power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple cutting edges are arranged closely together to improve material removal efficiency, then the removal area coverage is improved, but friction and heat generation increase enormously
Solution Approach 1:
The drill head is segmented into exactly two main cutting edges instead of three or more, creating distinct separation between cutting zones. This segmentation reduces the number of cutting edges from three to two, thereby reducing friction and heat generation while maintaining effective material removal through the optimized arrangement of these two edges.
2Productivity
If cutting edges are narrowly arranged to increase removal area coverage, then material removal efficiency improves, but bore dust discharge space is reduced
Solution Approach 1:
The two main cutting edges are arranged asymmetrically with unequal angular spacing around the drill axis. The first main cutting edge spans a first angular interval, and the second main cutting edge spans a second angular interval, where these intervals are not equal. This asymmetric arrangement creates unequal discharge spaces between the cutting edges, optimizing both material removal and bore dust discharge pathways.
3Manufacturing precision
If three main cutting edges are used to improve hole quality through support, then hole quality improves, but bore dust discharge time increases due to small spaces between edges
Solution Approach 1:
One main cutting edge is extracted from the traditional three-cutting-edge configuration, leaving exactly two main cutting edges. This extraction eliminates the congestion of three closely-spaced cutting edges, creating sufficient discharge space between the two remaining edges for efficient bore dust removal, while the two edges maintain adequate support for hole quality.
4Productivity
If cutting edges pass through the same radial portions multiple times, then material removal coverage is improved, but impact energy is absorbed by compressed bore dust in recesses
Solution Approach 1:
The asymmetric angular spacing of the two main cutting edges creates a dynamic pattern where each cutting edge encounters different radial portions of the borehole at different rotational positions. This dynamic arrangement prevents both cutting edges from simultaneously penetrating the same pre-existing recesses, reducing bore dust compression and maintaining drill feed rate and impact energy efficiency.
Data Source
AI summary
A drill head is provided with three main cutting edges each having a straight direction of extension with a predominant radial direction component. The directions of extension limit two adjacent main bore dust discharge sectors, each spanning a main sector angle. Three drill head cutting legs each forming a main cutting edge where the three main cutting edges have different lengths along their directions of extension. Concentric ring shaped removal areas overlap at least partially such that a triple removal area coverage is provided in an outer ring zone and a double removal area coverage is provided in an inner ring zone.