Drill Head Grooves with Expanding Cross-Section
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Solution Overview
Problem
Drills with one-piece drilling heads made of hard materials face issues with flow resistance and secondary comminution during drilling, leading to inefficient removal of drillings and contamination, particularly in small diameters.
Innovation Solution
The through-grooves in the drilling head have a region-wise increase in cross-section towards the bottom surface, acting as a check valve to reduce flow resistance and prevent secondary comminution, achieved through refining with non-prismatic pressing tools or metal injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If through-grooves have constant cross-section over the entire axial extent, then manufacturing is simplified, but flow resistance increases and drillings removal efficiency deteriorates
Solution Approach 1:
The through-grooves have different cross-sectional dimensions at different axial positions. The cross-section increases from the free end surface toward the bottom surface, creating local variations in geometry. This allows the grooves to have smaller cross-sections near the free end (reducing flow resistance) and larger cross-sections near the bottom (improving drillings removal), thus resolving the contradiction between manufacturing simplicity and removal efficiency.
2Productivity
If drillings are not removed rapidly enough, then secondary comminution occurs producing fine drilling dust, but increasing removal speed may increase flow resistance
Solution Approach 1:
The cross-sectional dimensions of the through-grooves are varied along the axial direction. By increasing the cross-section toward the bottom surface while maintaining smaller sections near the free end, the design optimizes the balance between removal speed and flow resistance, preventing secondary comminution without creating excessive resistance.
3Productivity
If through-grooves are tilted relative to axial extent, then drillings removal is improved, but secondary comminution still occurs
Solution Approach 1:
Instead of tilting the through-grooves relative to the axial extent (as in prior art), the invention inverts the approach by keeping the grooves axially extending but varying their cross-sectional dimensions along the axial direction. This alternative approach achieves improved drillings removal while eliminating secondary comminution, proving that the conventional tilted design was not the only solution.
Data Source
AI summary
A drill, which is used in a hammer drill for drilling holes in stone, concrete and the like, includes a one-piece drilling head (10, 20, 30) formed of a hard material and provided, at its first end (5), with at least one main bit having a tip (4) and at least one cutting structure (3) integral to the one-piece drilling head (10; 20; 30), and at a second end (6) located opposite the first end (5), with a bottom surface (7) for the mounting the drilling head (10; 20; 30) on the drill stem (8), and having a plurality of axially extending through-grooves (11; 21; 31) for removing drillings produced during a drilling process and having a cross-section which increases, at least regionwise, in a direction toward the bottom surface (7) of the drilling head (10; 20; 30).