Conical Segment Drill Bit for Easier Core Removal
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Solution Overview
Problem
Segmented drill bits face issues with drill core jamming, particularly for small diameters, due to fragments breaking off and getting stuck between the drill bit and core, making removal difficult.
Innovation Solution
The drill bit design features drilling segments with conical inner surfaces that taper towards the top, reducing contact surface area with the drill core, and varying inner distances to minimize contact, allowing only specific regions to engage with the core, thereby reducing jamming risks and simplifying core removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If drilling segments have a constant inner distance from the longitudinal axis (cylindrical inner surface), then the structure is simple and easy to manufacture, but the drill core is prone to jamming between the drill bit and core
Solution Approach 1:
The patent applies local quality by making the inner lateral surface of the drilling segments non-cylindrical, specifically conical or frustoconical, so that the inner distance from the longitudinal axis varies along the height of the segment. This creates zones of different contact characteristics: the smaller-diameter end reduces contact and prevents jamming, while the larger-diameter end provides sufficient support. This local variation in geometry resolves the contradiction between manufacturing simplicity and jamming prevention.
Solution Approach 2:
The patent changes the geometric parameter of the inner lateral surface from a constant radius (cylindrical) to a variable radius (conical or frustoconical). By changing the shape parameter from straight-sided to tapered, the inner distance from the longitudinal axis becomes a function of height rather than a constant, which reduces contact surface area and prevents core jamming while maintaining structural integrity.
2Strength
If drilling segments have a large contact surface with the drill core, then the support is good, but the drill core is prone to jamming and removal is difficult
Solution Approach 1:
The conical or frustoconical inner surface creates local quality variations where contact occurs primarily at the larger-diameter end of each segment, providing localized support points rather than continuous contact. This concentrated support is sufficient to hold the core while the reduced overall contact area prevents jamming and facilitates easy removal.
Solution Approach 2:
The patent uses conical or frustoconical surfaces (curved geometries) instead of cylindrical surfaces. The tapered curvature of the conical surface reduces the contact area between the drilling segments and the drill core, allowing the core to be supported at specific points while minimizing friction and preventing jamming, thus enabling easier core removal.
3Reliability
If the inner lateral surface is conical with varying inner distance, then the contact surface is reduced and jamming is prevented, but the manufacturing complexity increases
Solution Approach 1:
The patent changes the geometric parameter of the inner lateral surface from a constant radius to a variable radius that follows a conical or frustoconical profile. This parameter change effectively reduces the contact surface area between the drilling segments and the drill core, preventing jamming. While this increases manufacturing complexity compared to a simple cylinder, the conical shape remains a standard geometric form that can be manufactured using conventional machining or forming processes.
Data Source
AI summary
Drill bit (20) including a drilling shaft and a cutting portion having a first drilling segment (23-1) and a second drilling segment (23-2). The first drilling segment (23-1) has a first inner lateral surface (28-1) with a first inner distance (B1(φ), h)), and the second drilling segment (23-2) has a second inner lateral surface (28-2) with a second inner distance (B2(φ, h)) from the longitudinal axis (24) of the drilling shaft. The first inner lateral surface (28-1) is formed as a portion of a first inner cone (34-1) which tapers in the direction of a first upper side (32-1) opposite to the underside (31-1) of the first drilling segment (23-1).