Replaceable Head Cutting Tool Asymmetric Concave Design
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Solution Overview
Problem
Existing replaceable head cutting tools face issues with damage due to brittleness of the hard material used in the cutting head body and breakage of the punch during press-fitting, as the concave portion design either increases the risk of cracking or excessive deformation leading to punch breakage.
Innovation Solution
A replaceable head cutting tool design featuring a cylindrical coupling member with a concave portion having inclined first and second wall surfaces, where the first inclination angle is 45° or less and the second inclination angle is 45° or more, allowing for increased plastic deformation and reduced punch breakage risk while maintaining engagement strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the depth of the concave portion is increased to increase engagement strength, then the engagement strength between cutting head body and coupling member is improved, but cracks are generated from the bottom of the concave portion in the cutting head body due to its brittleness
Solution Approach 1:
The concave portion employs asymmetric wall surface inclinations where the first wall surface has a first inclination angle and the second wall surface has a second inclination angle that is smaller than the first. This asymmetric design creates different stress distribution patterns on each side, preventing stress concentration at the bottom of the concave portion while maintaining sufficient engagement strength between the cutting head body and coupling member.
2Strength
If the concave portion has a semi-oval cross-section with lengthened arc to increase plastic deformation, then the engagement strength is improved, but the punch breaks due to excessive load during press-fitting
Solution Approach 1:
The asymmetric inclination angles of the first and second wall surfaces create an optimized deformation path during press-fitting. The smaller second inclination angle reduces resistance to plastic deformation, allowing the coupling member to deform more easily into the concave portion without requiring excessive punch force, thereby preventing punch breakage while achieving sufficient engagement.
Solution Approach 2:
By optimizing the inclination angles of the wall surfaces as geometric parameters, the design controls the amount and distribution of plastic deformation during press-fitting. The specific parameter relationship (second inclination angle < first inclination angle) ensures adequate deformation for engagement while keeping deformation forces within safe limits for the punch.
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 enhances the strength of engagement between the tool body and coupling member, prevents damage to the tool body, and reduces the likelihood of punch breakage during press-fitting, ensuring reliable coupling and extraction resistance.
Implementation Method 1
the mounting unit is plastically deformed so as to increase in diameter
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A replaceable head cutting tool increases the strength of engagement between a tool body and a coupling member without causing damage to the tool body or the punch. A cylindrical mounting unit 21 of the coupling member 2, which is made of a metal material having hardness lower than the hardness of the tool body 1, is inserted into a mounting hole 16 that includes a concave portion 17 formed on the inner surface of the tool body 1 made of a hard material. The mounting unit 21 is plastically deformed so as to increase in diameter, and the outer peripheral surface of the mounting unit 21 comes into close contact with the inner peripheral surface of the mounting hole 16 and is engaged with the concave portion 17, so that the tool body 1 and the coupling member 2 are joined to each other. The concave portion 17 includes a first wall surface 17a that is inclined toward the outer peripheral side as the first wall surface moves in an insertion direction F of the mounting unit 21, and a second wall surface 17b that is opposite of the first wall surface 17a and is inclined toward the inner peripheral side as the second wall surface moves in the insertion direction F. A first inclination angle α, which is formed between the first wall surface 17a and a plane S perpendicular to a center line of the mounting hole 16 at a position where the first wall surface 17a intersects with the inner peripheral surface of the mounting hole 16, is smaller than a second inclination angle β, which is formed between the second wall surface 17b and the plane S at a position where the second wall surface 17b intersects with the inner peripheral surface of the mounting hole 16.