Replaceable Cutting Tool Fastening Structure for Low-Cost Circular Clamping
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Solution Overview
Problem
Existing head replaceable cutting tools face challenges in machining costs and shank deformation due to the need for multiple steps to create non-circular hole portions and the reduction in shank thickness when clearance portions are provided in the clamping surface.
Innovation Solution
A head replaceable cutting tool design featuring a circular hole portion with a fastening projection portion having radial inward clearance portions on its outer circumference, allowing for single-step drilling and maintaining sufficient material thickness to prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hole portion is shaped in a non-circular shape to form a clearance portion, then the clearance portion is formed for head attachment/detachment, but the machining steps increase and work time increases
Solution Approach 1:
Instead of forming the clearance portion by making the hole portion non-circular, the invention inverts the approach by keeping the hole portion circular and forming the clearance portion on the projection portion's outer circumference surface. This allows the hole to be drilled in a single step while the clearance is created on the easier-to-machine projection portion.
2Reliability
If the hole portion is shaped in a non-circular shape to form a clearance portion, then the clearance portion is formed for head attachment/detachment, but the machining cost increases
Solution Approach 1:
The invention transfers the clearance portion formation from the hole portion to the projection portion. This inversion allows the hole to be machined simply by drilling, while the clearance is formed on the projection portion which can be more easily machined, thereby reducing overall machining cost.
3Reliability
If the clearance portion is provided in the clamping surface of the shank, then the clearance portion is formed for head attachment/detachment, but the shank thickness is reduced causing deformation
Solution Approach 1:
The invention extracts the clearance portion from the shank's clamping surface and relocates it to the projection portion. This separation allows the shank to maintain its full thickness and strength for proper clamping, while the clearance function is achieved on the projection portion that does not bear the clamping load.
4Reliability
If the clearance portion is provided in the clamping surface of the shank, then the clearance portion is formed for head attachment/detachment, but the shank deforms under external pressure
Solution Approach 1:
The clearance portion is extracted from the shank and placed on the projection portion. This ensures the shank maintains its structural integrity and stability under external pressure, while the projection portion with the clearance portion handles the attachment/detachment function without compromising shank stability.
Data Source
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AI summary
A head replaceable cutting tool having a structure that can limit a machining cost when a clearance portion is formed in a portion at which a head is attached and detached, and also limit deformation of a shank is provided. The head replaceable cutting tool includes: a projection portion or a hole portion for attachment and detachment disposed in a head; a shank to which the head is attachable; a hole portion, to which the projection portion is removably attachable along a central axis, or a projection portion disposed in an end portion of the shank; a fastening member that presses the projection portion toward an inner circumference surface of the hole portion; and a fastened portion disposed in the shank to fasten the fastening member. The hole portion has a transverse cross-sectional shape that is a substantially circular shape having a curvature radius R1, and the projection portion has a transverse cross-sectional shape including a contact portion at which an outer circumference surface of the projection portion is in contact with the inner circumference surface of the hole portion and a clearance portion that is formed in a part of the outer circumference surface so as to deviate radially inward from a virtual circle corresponding to the inner circumference surface and does not come into contact with the inner circumference surface.