Cutter Holder Thread Tolerance and Sealing Design
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Solution Overview
Problem
Conventional cutter holders experience poor connection and eccentricity due to machining accuracy issues in threaded connections, leading to reduced machining accuracy and balance problems during rapid spinning.
Innovation Solution
A cutter holder design featuring a conical recess, multiple threaded portions with specific abutting surfaces and sealing members, and a threaded connection that minimizes clearance between the external and internal trapezoidal threads, ensuring a firm connection and reducing eccentricity through interference fits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional threaded connection with standard tolerance classes (7H/7e) is used, then ease of manufacture is improved, but manufacturing precision deteriorates due to large gap between threads
Solution Approach 1:
The patent changes the tolerance parameters from conventional 7H/7e to tighter tolerances (6H/6e or 5H/5e), directly reducing the gap between external and internal threads from 0.461mm to less than 0.015mm, thereby improving connection precision without fundamentally changing the manufacturing process
Solution Approach 2:
The patent specifies predetermined tolerance values for the external and internal threads before assembly, ensuring that the gap between threads is controlled at less than 0.015mm in advance, which prevents eccentricity and poor connection before the assembly is put into operation
2Ease of operation
If larger clearance between threads is allowed, then ease of assembly is improved, but reliability deteriorates due to poor connection and eccentricity
Solution Approach 1:
The patent tightens the clearance parameter between the external thread (911) and internal thread (931) to less than 0.015mm, eliminating the conventional 0.461mm gap, which ensures firm connection and prevents eccentricity while maintaining assembly feasibility through precise machining specifications
3Ease of manufacture
If conventional thread tolerance is used, then manufacturing cost is reduced, but machining precision deteriorates due to vibration and poor balance during rapid spinning
Solution Approach 1:
The patent specifies tighter tolerance parameters (6H/6e or 5H/5e instead of 7H/7e) for the thread pitch diameter, reducing the gap between threads and eliminating vibration and balance problems during rapid spinning, thereby improving machining precision while controlling manufacturing cost through standardized precision grading
Data Source
AI summary
A cutter holder has a holder, a collet, and a nut. The holder has a first threaded portion having an external thread, a first abutting surface, a second abutting surface, at least one recess, and at least one sealing member. The at least one recess is recessed in the second abutting surface. The at least one sealing member is mounted in the at least one recess and partially protrudes from the second abutting surface. The nut has a second threaded portion having an internal thread, a third abutting surface, and a fourth abutting surface. The internal thread and the external thread are corresponding internal and external trapezoidal threads, respectively. The third abutting surface and the first abutting surface have a corresponding diameter with a clearance therebetween being less than 0.015 millimeter. The fourth abutting surface and the at least one sealing member are in an interference fit.