Thread Forming Tool Groove Geometry for Lower Torque and Wear

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Solution Overview

Problem

Thread forming tools for internal threads in metal workpieces experience severe stress, high wear, and temperature issues, leading to reduced performance and shorter service life, along with increased torque requirements.

Innovation Solution

The thread forming tool features thread grooves with a smaller angle configuration, allowing for sharper thread forming profiles that reduce wear and torque, and includes a distribution of first and second thread grooves for improved cooling and lubrication fluid transportation, enhancing machining performance and service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional thread grooves with equal angles are used, then the tool structure is simple and easy to manufacture, but the wear resistance is poor and torque requirements are high

Engineering Contradiction:
Improvewear resistanceVSAvoidthread groove angle configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by differentiating the flank angles of thread grooves along the thread forming portion. Specifically, the first thread groove has a smaller included angle (α) than the second thread groove, creating localized variations in geometry that reduce wear and torque requirements at critical areas while maintaining overall tool functionality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements asymmetry by using non-uniform flank angles for different thread grooves. The first thread groove has a smaller included angle compared to the second thread groove, breaking the symmetry of conventional thread forming tools and optimizing performance characteristics such as wear resistance and torque reduction.

Inventive Principle:
Principle #4Asymmetry

2Temperature

If conventional thread grooves are used, then the tool design is straightforward, but the cooling and lubrication fluid supply is insufficient

Engineering Contradiction:
Improvecooling and lubrication fluid supplyVSAvoidthread groove distribution
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating specific thread groove configurations that optimize fluid flow pathways. The varied flank angles and distributed arrangement of first and second thread grooves create localized channels that enhance cooling and lubrication fluid supply to high-temperature zones during thread forming operations.

Inventive Principle:
Principle #3Local quality

3Force

If thread forming profiles with larger angles are used, then the tool is more durable, but the torque needed to form threads increases

Engineering Contradiction:
Improvetorque requirementVSAvoidtool durability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent applies parameter changes by varying the included angles of different thread grooves. The first thread groove has a smaller included angle (α) compared to the second thread groove, creating an optimized parameter distribution that reduces the force required for thread forming while maintaining tool durability through the varied geometric configuration.

Inventive Principle:
Principle #35Parameter changes

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 solution results in reduced wear and torque requirements, improved machining efficiency, and extended tool life by optimizing the angle configuration and distribution of thread grooves for better fluid transportation, leading to enhanced thread forming capabilities.

Implementation Method 1

the thread forming profiles will be pressed into the surface of the workpiece, causing a re-shaping or deformation of the workpiece material so that a screw thread is formed

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

When using cooling and/or lubricating fluid, said first thread groove allows for advantageous transportation of such fluid closer to the thread forming ridges of associated thread forming profiles

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3300825B1A thread forming tool
Publication Date: 2021.07.07 WALTER AG
  • EP3300825B1 patent drawingFigure 1~2
  • EP3300825B1 patent drawingFigure 3~4
  • EP3300825B1 patent drawingFigure 5~6

AI summary

A thread forming tool (10) for forming an internal thread in a workpiece, the thread forming tool comprising a shank (1) and a thread forming portion (2), which are rotatable around a common axis (50), said axis extending in a longitudinal direction of the thread forming tool (10), the thread forming portion (2) having a plurality of radially protruding lobe portions (3) being circumferentially spaced-apart by relief portions (6), said lobe portions (3) having in the longitudinal direction a plurality of thread forming profiles, each thread forming profile having a radially outermost ridge (4), being connected to a first flank and a second flank, wherein a first flank of a first thread forming profile is connected to a second flank of an adjacent second thread forming profile via a thread groove (5), said lobe portions (3) having in the longitudinal direction a plurality of thread grooves (5). The flanks of at least one first thread groove encloses a first angle, which is smaller than a second angle enclosed by the flanks of at least one second thread groove.