Drill Insert With Staggered Cutting Edges
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Solution Overview
Problem
Existing drills face challenges in efficiently transmitting torque force due to strong shearing forces, leading to weakened cross-sections and reduced drilling efficiency, particularly when dealing with hard materials like concrete.
Innovation Solution
The drill design features cutting edges with varying heights and angles, where the difference in insert heights is at least 15% of the total height, and at least two cutting edges have main chip surfaces with decreasing clearance angles, ensuring better power transmission and material penetration, while maintaining structural integrity and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If cutting edges are positioned at the same level, then the structure is simpler, but power transmission is weakened due to strong shearing forces
Solution Approach 1:
The patent transitions from a two-dimensional arrangement (all cutting edges at the same level) to a three-dimensional arrangement (cutting edges at different heights). By positioning cutting edges at multiple levels along the drill axis, the invention creates staggered cutting paths that reduce simultaneous engagement, thereby reducing shearing forces and improving power transmission while maintaining structural integrity.
2Productivity
If all cutting edges engage the material simultaneously, then drilling speed increases, but shearing forces become too strong
Solution Approach 1:
The patent segments the cutting action by dividing the four cutting edges into different height levels. This segmentation ensures that not all cutting edges engage the material simultaneously during drilling, thereby reducing the peak shearing forces while maintaining continuous cutting action and drilling productivity.
3Ease of manufacture
If clearance angle is constant along the cutting edge, then manufacturing is easier, but wear resistance decreases at outer areas
Solution Approach 1:
The patent applies local quality by varying the clearance angle along the length of the cutting edge. The clearance angle is smaller near the tip area and larger at the outer areas. This local variation optimizes wear resistance at different positions: the smaller angle at the tip provides better cutting action, while the larger angle at the outer areas reduces friction and wear, extending tool life.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances drilling speed, stability, and wear resistance, allowing for deeper penetration and longer service life, with reduced vibration and risk of polygonal boreholes, while maintaining even wear across cutting edges for improved cost-effectiveness.
Implementation Method 1
a drill (2) with a multiple cutting insert (10), in particular for percussion drilling, with four main cutting edges (12, 14, 16, 18), two of which are located on first (20) and second (22) insert bodies (20, 22) which intersect, wherein the first and second insert bodies (20, 22) have different heights, specifically plate heights T1 and T2
Implementation Method 2
each principal clearance angle decreases with increasing distance from the drill bit. Due to the main clearance angle decreasing with increasing distance from the drill bit, the main cutting edges are secured against wear or breakage
Implementation Method 3
An even higher strength of the multi-cutting insert is given when the angle α is between 20° and 40°. This has the advantage that an even larger material area is formed integrally in the case of the intersecting plate bodies
Data Source
Figure 1a~1b
Figure 2~4
AI summary
The borer has a front end with slots in a boring direction for the admission of a multi-cutting plate. The multi-cutting plate has four cuttings, where the cuttings are arranged in crossing disk bodies (20, 22). The disk bodies have different disk heights (T1, T2) and depths. Two neighboring cuttings form an angle (b1) from 10 to 90 degrees. The four cuttings are provided on four different levels.