Self-Cutting Thread Insert Conical Groove Design

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Solution Overview

Problem

The production of self-tapping threaded inserts is costly and time-consuming due to complex cutting geometries, which often damage the internal thread and require additional cleaning to remove chips, increasing tool wear and reducing throughput.

Innovation Solution

A threaded insert with a concave cutting groove defined by the intersection of a conical body, featuring a cutting angle greater than the angle of inclination, which penetrates deeply into the base body without interrupting the internal thread, allowing for effective chip removal and easy production, and a method using a rotating saw blade to create cutting grooves without touching the internal wall.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex cutting geometries are used to achieve good cutting results, then cutting performance is improved, but production cost increases and manufacturing complexity increases

Engineering Contradiction:
Improvecutting performanceVSAvoidcutting groove geometry
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cutting groove is designed with a conical shape instead of complex geometries. The conical body with its smooth curved surfaces simplifies manufacturing while maintaining effective cutting performance. The conical geometry naturally guides chip removal and provides adequate cutting edges without requiring complex contours.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If cutting grooves are formed by through holes or slot-like incisions, then cutting edges are created, but the internal thread is weakened and chips enter the interior

Engineering Contradiction:
Improvecutting edge formationVSAvoidinternal thread strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The cutting groove is localized to the conical area at the first end face, leaving the internal thread in the cylindrical area intact and strong. The conical body confines the cutting groove to specific regions where cutting edges are needed, while the internal thread remains undisturbed in the cylindrical portion, maintaining its full strength.

Inventive Principle:
Principle #3Local quality

3Reliability

If conventional cutting grooves are used, then cutting edges are formed, but chip removal is insufficient and additional cleaning is required

Engineering Contradiction:
Improvecutting edge formationVSAvoidchip removal efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The conical shape of the cutting groove creates a self-cleaning effect where chips are naturally guided outward along the conical surfaces. The curved conical geometry prevents chip accumulation and facilitates automatic chip ejection during installation, eliminating the need for additional cleaning operations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Productivity

If the cutting groove penetrates deeply into the base body, then chip removal is improved, but the internal thread may be damaged

Engineering Contradiction:
Improvechip removalVSAvoidinternal thread integrity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The conical body confines the cutting groove penetration to the conical area, ensuring that even deep penetration for effective chip removal does not compromise the internal thread located in the cylindrical area. The geometric separation between the conical cutting zone and cylindrical thread zone protects thread integrity while maximizing chip removal capability.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3232070B1Self-cutting thread insert and method for its production
Publication Date: 2019.02.20 FAIRCHILD FASTENERS EURO
  • EP3232070B1 patent drawingFigure 1~6
  • EP3232070B1 patent drawingFigure 7~8

AI summary

The invention relates to a self-tapping threaded insert with a sleeve-like base body (1) and to a method for manufacturing a threaded insert. The base body (1) extends along a longitudinal axis (I) from a first end face (2) to a second end face (3) and has an outer diameter that decreases in a conical region (7). A through-opening (4) with a closed inner wall is provided in the base body (1). Furthermore, the base body (1) has an internal thread (6) and an external thread (7). In the conical region (7) of the external thread (5), at least one cutting groove (8) is provided, which is defined by a recess in the base body (1), the shape of which is essentially defined by the intersection of the base body (1) with a conical body having a conical base surface (11), a conical lateral surface (12), and an axis of symmetry (II).The intersection point of the axis of symmetry (II) with the cone base surface (11) lies either in the plane defined by the first end face (2) or is offset away from the second end face (3). An angle of intersection (α) can be greater than an angle of inclination (β) of the axis of symmetry (II).