T-Shaped Tool Tapered Thread Joint for Rigid Carbide Shanks
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Solution Overview
Problem
Existing T-shaped tools face challenges in securely attaching the cutting head to the shank due to the low tensile strength of cemented carbide, leading to rigidity issues and difficulties in maintaining machining accuracy and efficiency.
Innovation Solution
The T-shaped tool employs tapered external and internal threads for the shank and tool body connection, allowing for a high fastening torque without axial tensile load on the shank, thereby utilizing cemented carbide for enhanced rigidity and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cemented carbide is used for the shank to achieve high rigidity, then machining accuracy improves, but the low tensile strength of cemented carbide makes thread connection difficult
Solution Approach 1:
The patent changes the stress parameter from tensile to compressive through inverted thread configuration. This allows cemented carbide shanks to be used because the material excels in compressive strength. The left-handed thread on the shank combined with right-handed thread on the cutting head creates a compressive preload that the cemented carbide can withstand, enabling high rigidity and machining accuracy.
2Reliability
If the shank is tensioned by the fixation screw, then the cutting head is secured to the shank, but the thread lacks rigidity due to continuous tensile load
Solution Approach 1:
The patent inverts the thread configuration to reverse the loading direction. The left-handed shank thread with right-handed cutting head thread creates compressive force that pushes the cutting head against the shank, eliminating continuous tensile load. This inversion stabilizes the thread structure and prevents loosening while maintaining high connection reliability.
Solution Approach 2:
The inverted thread configuration creates a preliminary compressive action that prevents thread loosening before it can occur. The compressive preload generated by the inverted threads acts in opposition to any loosening forces, maintaining thread rigidity and connection stability throughout operation.
Data Source
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AI summary
Provided is a T-shaped tool (10) configured by fastening a head (30) having cutting blades (36, 38) to a cylindrical shank (20), wherein the shank (20) is made of cemented carbide and has a tapered male thread (24) formed at a tip end portion thereof, the tapered male thread (24) becoming smaller in diameter toward the tip end, and the head (30) is made of steel and has a tapered female thread (50) formed therein, the tapered female thread (50) coming into engagement with the tapered male thread (24).