Drill Head Ridge Layout for Small-Diameter Tool Balance
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Solution Overview
Problem
Existing drills face instability and balance issues as the outer diameter decreases, leading to a decrease in the fitting force between the recesses and protrusions, affecting the stability and tool balance.
Innovation Solution
The drill head design includes a first attachment surface with symmetric helical flutes and ridges that maintain stability and balance by supporting the holder at three points, with specific angle configurations and asymmetric ridge arrangements to distribute stress evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the outer diameter of the drill decreases, then the drill can be used for smaller holes and more precise work, but the fitting force between the recesses and protrusions decreases leading to instability
Solution Approach 1:
The patent applies asymmetry by providing three ridges on the drill head that are asymmetrically arranged relative to the central axis, rather than symmetrically. Specifically, the first ridge is positioned at a different angular position than the second and third ridges. This asymmetric configuration creates an uneven distribution of contact points with the holder, generating a balancing moment that counteracts centrifugal forces during rotation, thereby maintaining tool balance and stability even when the outer diameter is reduced.
2Volume of moving object
If the outer diameter of the drill decreases, then the drill can be used for smaller holes, but the tool balance deteriorates due to uneven mass distribution
Solution Approach 1:
The patent introduces asymmetry in the ridge arrangement to deliberately create a mass distribution that balances centrifugal forces. The three ridges are positioned at specific angular intervals that are not equal, with the first ridge at a different position than the second and third ridges. This asymmetric mass distribution generates a counterbalancing moment that offsets the uneven centrifugal forces generated during rotation, maintaining tool balance even in small-diameter drills.
3Reliability
If the number of ridges is increased to improve support stability, then the fitting force increases, but the device complexity increases
Solution Approach 1:
The patent applies local quality by concentrating the support function at three specific localized ridges rather than distributing it uniformly across the entire attachment surface. Each ridge is strategically positioned to provide localized contact points with corresponding grooves in the holder, creating sufficient support and fitting force with minimal structural elements. This localized approach achieves stable support without requiring a high number of ridges, thereby avoiding increased device complexity.
Data Source
AI summary
A drill head includes a first attachment surface attached to a holder, a head tip surface opposite to the first attachment surface in an axial direction along the central axis, and a head outer peripheral surface continuous with the first attachment surface and the head tip surface. The head outer peripheral surface is provided with a first flute and a second flute extending helically about the central axis from the head tip surface to reach the first attachment surface. The first flute and the second flute are symmetric with respect to the central axis. Each of the first flute and the second flute has a first end and a second end that face each other with a space between them in a circumferential direction along a circumference centered on the central axis.