Drill Support Edge Linear Contact Friction Reduction
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Solution Overview
Problem
Drills experience high friction and thermal load due to guide and support chamfers, leading to early wear and reduced true-running accuracy during drilling.
Innovation Solution
A drill design with a guide chamfer adjacent to the leading flute and a support chamfer in the rearward region, featuring a continuous clearance with a reduced radius and a linear support edge that punctually contacts the drill hole wall, minimizing friction and thermal load by reducing the support surface area and angular extent of the support chamfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If guide chamfer and support chamfer are formed on the rear surface, then true-running accuracy is improved, but friction and thermal load increase leading to early wear
Solution Approach 1:
The invention extracts the support function from the traditional support chamfer by creating a support edge that forms only a linear contact point with the drill hole wall. This removes the harmful friction and thermal load associated with traditional support chamfers while maintaining the necessary support function for true-running accuracy
Solution Approach 2:
The invention applies local quality by creating a support edge with specific geometric characteristics (linear contact, punctual contact point) in a specific location on the rear surface. This localized design ensures support where needed while minimizing contact area to reduce friction and thermal load
2Stability of the object's composition
If support chamfer extends over several angular degrees, then support stability is improved, but contact area increases leading to higher friction and thermal load
Solution Approach 1:
The invention applies partial action by providing support through a minimal contact point rather than extended contact. The support edge extends over a small angular range (less than 1°, preferably 0.1° to 0.5°), which is sufficient for maintaining true-running accuracy while minimizing friction and thermal load
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
The design ensures high true-running accuracy and reduced thermal load by minimizing friction, allowing for elastic deformation of the drill hole wall and preventing groove formation, while maintaining dimensional stability and accuracy.
Implementation Method 1
the support chamfer comprises only a support edge as the radially outermost region so that a merely linear contact to the drill hole wall occurs during operation. This design is based on the consideration that a linear contact is sufficient for the support in order to ensure the desired high true-running accuracy
Implementation Method 2
As a result of the small support surface compared to traditional support chamfers, the pressing force per unit of area is increased, whereby an at least minor elastic penetration of the support edge into the drill hole wall can occur. This means that an elastic deformation of the drill hole inner wall can occur as a result of the support edge
Data Source
AI summary
The drill comprises a base body, which extends in the axial direction along an axis of rotation and rotates about the axis of rotation in a direction of rotation during operation. Into the base body are incorporated flutes and between consecutive flutes is formed a rear surface, which extends, in relation to the direction of rotation, from a leading flute to a trailing flute. On the rear surface in the region of the leading flute, a guide chamfer and a support chamfer spaced apart from it in the direction opposite the direction of rotation are formed, wherein the support chamfer, as radially outermost region, forms a support edge for a merely linear support.