Modular Drill Tip Clamping Structure for Lower Stress Concentration
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Solution Overview
Problem
Conventional drills with replaceable cutting tips face deformation and failure due to stress concentration in the retaining and drive structure, limiting their service life.
Innovation Solution
A rotary cutting tool design featuring a shank with a pocket for an interchangeable cutting tip, where the centering walls and torque transmission walls are oriented at specific angles to reduce stress and improve torque transmission, using a holding element and bump-off mechanism for secure clamping and easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional retaining and drive structure is used in drills, then the drill can perform cutting operations, but stress concentration occurs leading to deformation and failure
Solution Approach 1:
The pocket is segmented into multiple functional surfaces: centering wall portions for positioning, torque transmission walls for force transfer, and holding element for clamping. This segmentation distributes stresses to different dedicated surfaces rather than concentrating them in a single retaining structure.
Solution Approach 2:
Different wall portions are optimized for specific functions: centering walls provide precise positioning, torque transmission walls are oriented at specific angles (75-120 degrees) for optimal force distribution, and the holding element provides localized clamping. Each surface has tailored geometry to handle specific stress types.
2Adaptability or versatility
If cutting tips are made interchangeable for ease of replacement, then adaptability improves, but the retaining structure becomes more complex and prone to failure
Solution Approach 1:
The pocket structure serves multiple functions simultaneously: it centers the cutting tip, transmits torque, and provides clamping through the holding element. This multi-functional design eliminates the need for separate retaining mechanisms, simplifying the overall structure while enabling easy tip replacement.
Solution Approach 2:
The bump-off element enables self-release of the cutting tip by displacing the holding element from the clamped position. The interference fit and angled walls work together to automatically position and secure the tip without additional fastening operations.
3Reliability
If centering walls are oriented at specific angles for stress reduction, then durability improves, but manufacturing precision requirements increase
Solution Approach 1:
The wall orientations are defined by specific angle ranges (75-120 degrees for torque transmission walls relative to centering walls) that optimize stress distribution. These angular parameters are designed to accommodate reasonable manufacturing tolerances while achieving the stress reduction objective.
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 angled design reduces stress concentrations, enhancing the durability and service life of the drill by maintaining face-to-face contact and minimizing deformation during operation.
Implementation Method 1
the shank comprising a pocket which receives the interchangeable cutting tip via an interference fit
Data Source
AI summary
A rotary cutting tool with a shank and an interchangeable cutting tip, wherein the shank includes a pocket which receives the interchangeable cutting tip via an interference fit. The pocket includes two centering wall portions which, when viewed along a central longitudinal axis, are oriented at a first angle with respect to one another, the first angle being greater than zero. The interchangeable cutting tip is axially displaceable between: an initial position, assumed upon being received in the pocket of the shank; a clamped position, wherein the interchangeable cutting tip is fixedly held with respect to the shank; and a bump-off position, wherein the interchangeable cutting tip is not fixedly held. A holding element holds the interchangeable cutting tip in the clamped position, and a bump-off element displaces the interchangeable cutting tip between the clamped position and the bump-off position. Other variants and embodiments are broadly contemplated herein.