Thread Forming Tap Geometry for Female Thread Diameter Control
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Solution Overview
Problem
Existing thread forming taps require precise dimension accuracy of the prepared hole to achieve targeted processing accuracy for female threads, which can be challenging and restrictive.
Innovation Solution
A thread forming tap with a male thread portion featuring alternately arranged protruding and adjustment portions, where the adjustment portions allow for the adjustment of the inside diameter of the female thread, enabling targeted processing accuracy without strict dimension accuracy of the prepared hole, and include second thread ridges and roots to prevent excessive deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the diameter of the prepared hole is adjusted with high degree of accuracy, then the inside diameter dimension of the female thread achieves targeted processing accuracy, but the manufacturing complexity and difficulty increase
Solution Approach 1:
The male thread portion is segmented into protruding portions and adjustment portions, where each protruding portion has thread ridges for forming the female thread, and each adjustment portion has a different radial distance to control the inside diameter. This segmentation allows the tap to simultaneously perform thread formation and diameter adjustment without requiring high precision in the prepared hole.
Solution Approach 2:
The invention changes the radial distance parameter from the axial center to the adjustment portion for each adjustment portion, creating a gradient structure where each adjustment portion has a progressively smaller radial distance. This parameter variation enables the tap to adjust the inside diameter of the female thread to different dimensions while maintaining thread formation functionality.
2Manufacturing precision
If the radial distance from axial center to adjustment portion is reduced, then the inside diameter of female thread is adjusted to smaller dimensions, but excessive deformation of the workpiece may occur
Solution Approach 1:
Different portions of the male thread are given different local qualities: the protruding portions have thread ridges for plastic deformation and thread formation, while the adjustment portions have optimized radial distances for diameter control. This local differentiation ensures that each portion performs its specific function without causing harmful excessive deformation.
Solution Approach 2:
The adjustment portions are designed with dynamic radial distances that can be optimized for different workpiece materials and thread requirements. The radial distance from the axial center to each adjustment portion can be adjusted to control the degree of plastic deformation, preventing excessive deformation while achieving the desired inside diameter.
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 tap efficiently forms female threads with accurate inside diameters, even with varying prepared hole dimensions, and prevents excessive deformation, ensuring stable and precise thread formation.
Implementation Method 1
forming a female thread by causing plastic deformation of a prepared hole of a workpiece
Implementation Method 2
a distance from an axial center to a section of the adjustment portion corresponding to the first root in the one lead is longer than a root diameter of the first root and shorter than a ridge diameter of the first thread ridge adjacent to the first root
Data Source
AI summary
An object is to provide a thread forming tap configured to obtain an inside diameter dimension of a female thread having a targeted processing accuracy more easily than in related art. A thread forming tap (1) is a cold forming tap for forming a female thread by causing plastic deformation of a prepared hole of a workpiece, and includes a male thread portion (3) that protrudes in a thread shape in a radial direction. The male thread portion includes at least one protruding portion (5), which includes a plurality of first thread ridges (51) arranged in an axial direction and that protrude in the radial direction and a first root (52) formed between the first thread ridges adjacent to each other in the axial direction, and at least one adjustment portion (6), which is arranged with the at least one protruding portion in one lead of the male thread portion. A distance from an axial center to a section of the adjustment portion corresponding to the first root in the one lead is longer than a root diameter of the first root and shorter than a ridge diameter of the first thread ridge adjacent to the first root.