Segmented Thread-Forming Tool for Blind Holes
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Solution Overview
Problem
Existing methods for producing threads in workpieces, particularly internal threads, often require starting cones or lead areas that result in incomplete thread turns and longer tool lengths, which complicates the process, especially in blind holes and reduces efficiency.
Innovation Solution
The method involves creating grooves around the thread axis and using a thread-forming tool with thread-cutting or thread-forming areas that rotate and axially feed to generate threads without a starting cone, allowing for complete thread turns over a greater length and enabling quicker tool insertion, rotation, and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a starting cone or lead area is used in conventional threading tools, then the tool can engage the workpiece gradually, but the thread length is reduced and incomplete thread turns occur
Solution Approach 1:
The threading tool is divided into multiple thread generation areas arranged axially, with each area responsible for generating a portion of the thread. This segmentation allows the thread to be formed in discrete sections along the axial direction, eliminating the need for a continuous starting cone while maintaining complete thread turns throughout the threaded portion.
Solution Approach 2:
The invention transitions from conventional radial thread generation (single point contact) to axial thread generation by arranging multiple thread generation areas along the axial direction. This dimensional change allows simultaneous thread formation at multiple axial positions, eliminating the length penalty associated with starting cones.
2Manufacturing precision
If conventional threading tools are used, then the threading process is continuous, but the tool length increases and positioning precision decreases
Solution Approach 1:
The tool is segmented into distinct thread generation areas separated by non-threaded sections. This segmentation reduces the overall tool length required for thread formation and enables precise axial positioning of each thread generation area, improving manufacturing precision while reducing tool dimensions.
Solution Approach 2:
The thread generation areas are pre-positioned at specific axial locations on the tool, allowing for precise axial positioning during the threading operation. This preliminary arrangement of functional elements enables accurate thread placement without requiring long tool overhangs.
3Productivity
If multiple revolutions are required for threading, then complete thread formation is achieved, but the production time increases
Solution Approach 1:
By dividing the thread generation function into multiple axial segments, the threading process can achieve complete thread formation in fewer revolutions. Each thread generation area contributes to thread formation simultaneously during rotation, reducing the total number of revolutions required and increasing productivity.
Solution Approach 2:
The multiple thread generation areas enable continuous thread formation along the axial direction during a single rotation cycle, eliminating idle time between thread sections and reducing the total threading cycle time while maintaining complete thread formation.
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
This method eliminates the need for starting cones, reduces tool length, and significantly shortens the time required to produce threads, allowing for precise axial positioning and efficient thread creation, even in blind holes, with fewer revolutions and faster tool movement.
Implementation Method 1
Machining thread production is based on material removal of the material of the workpiece in the area of the thread
Implementation Method 2
The pressure lugs of the cold-forming tap are permanently in engagement with the workpiece on the core hole wall and press the thread through plastic deformation into the core hole wall
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The method for producing a thread in a workpiece comprises the following method steps: a) producing a wall of the workpiece, said wall having a number n of grooves greater than or equal to 1 and running round a thread axis, b) introducing in each case one thread-producing region (32, 34) of a thread-producing tool (3) into each of the grooves, c) producing a thread (36) in each subregion (23, 25), adjoining the groove(s), of the wall of the workpiece by rotating the thread-producing tool (3) about the thread axis (M), wherein, following rotation, each thread-producing region projects into the same groove again or into another groove in the wall, d) moving each thread-producing region (32, 34) of the thread-producing tool out of the associated groove (24, 22) in the direction along the groove.