Self-Piercing Press-In Element with Displacement Ridge

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Solution Overview

Problem

Self-piercing press-in elements, such as pierce nuts, face challenges in achieving reliable axial pull-out strength and anti-twist security while maintaining a compact size, often compromising on weight savings and installation space in lightweight metal components.

Innovation Solution

A self-piercing press-in element with a stamped collar featuring a conically inclined outer lateral surface and a circumferential displacement web that presses sheet metal material into an undercut, providing axial pull-out protection and anti-twist security through friction, without the need for additional form-fitting elements or deformation of the component's underside.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the press-fit element is made compact to reduce weight and save space, then weight reduction and space efficiency are improved, but axial pull-out strength and torsional rigidity deteriorate

Engineering Contradiction:
Improveweight of press-fit elementVSAvoidaxial pull-out strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The head support surface is segmented into two functional zones: an inner pressing area that contacts the die during installation, and an outer annular displacement area that engages the sheet metal component. This segmentation allows the compact structure to generate sufficient pressing force through the concentrated inner area while the outer area provides extended engagement for pull-out resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The displacement area extends radially outward from the pressing area, utilizing the radial dimension to increase the effective engagement area without increasing the axial height of the press-fit element. This allows the compact element to achieve sufficient surface area for friction-based pull-out resistance without compromising weight or space efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Weight of moving object

If the press-fit element is made compact to reduce weight and save space, then weight reduction and space efficiency are improved, but torsional rigidity deteriorates

Engineering Contradiction:
Improveweight of press-fit elementVSAvoidtorsional rigidity
Core Design Contradiction:
Weight of moving objectVSStability of the object's composition

Solution Approach 1:

The head support surface is segmented into a centralized pressing area and a surrounding displacement area. This segmentation creates a lever arm effect where the radial distance between the pressing area and displacement area provides mechanical advantage for resisting rotational forces, enhancing torsional rigidity without increasing overall element size.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By utilizing the radial dimension through the annular displacement area, the element achieves greater moment of inertia for resisting torsional loads. The radial extension provides leverage against rotational forces while maintaining compact axial dimensions, thus improving torsional rigidity without adding weight.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Strength

If conventional designs with additional form-fitting elements are used, then axial pull-out strength and anti-twist security are improved, but device complexity increases

Engineering Contradiction:
Improveaxial pull-out strengthVSAvoidstructural complexity of press-fit element
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The head support surface performs multiple functions: it provides bearing contact during installation through the pressing area, generates friction-based pull-out resistance through the displacement area, and creates lever arms for torsional resistance. This multi-functionality eliminates the need for separate form-fitting elements, reducing structural complexity while maintaining strength.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The displacement area automatically engages the sheet metal component during the pressing operation itself, using the installation process to create the friction-based locking mechanism. No additional forming steps or separate locking elements are required, simplifying the overall device design while achieving reliable pull-out and anti-twist security.

Inventive Principle:
Principle #25Self-service

4Strength

If material is displaced into undercut from top surface, then axial pull-out protection and anti-twist security are improved, but the component top surface is deformed

Engineering Contradiction:
Improveaxial pull-out protectionVSAvoidsmoothness of component surface
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The head support surface is divided into a pressing area that contacts the die and a displacement area that engages the component. This segmentation confines the material displacement action to the annular displacement area, preventing deformation of the central hole region and maintaining surface smoothness where it is most critical.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By utilizing the radial dimension through the annular displacement area, the element achieves material displacement and locking without requiring axial deformation of the component surface. The displacement occurs in the radial plane, preserving the axial smoothness of the component surface while still achieving pull-out protection.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 ensures a reliable press-fit connection with enhanced axial pull-out and anti-twist resistance, maintaining a compact size and smooth component underside, achieving high filling efficiency and sufficient strength even in small-sized elements.

Implementation Method 1

material from the top of the component is displaced and thus pressed into the undercut or recess by means of a forming process

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

The displacer ridge therefore generates additional, advantageous friction in the pressed-in state

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

This is achieved both through the circumferential friction of the displacer ridge and through the friction between the pressed-in material and the outer surface of the stamping collar

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3430277B1Self-piercing press-in element, press-in connection, and method for producing such a press-in connection
Publication Date: 2020.10.21 RICHARD BERGNER VERBINDUNGSTECHNIK GMBH & CO KG
  • EP3430277B1 patent drawingFigure 1~2
  • EP3430277B1 patent drawingFigure 3~5
  • EP3430277B1 patent drawingFigure 6

AI summary

The invention relates to a self-piercing press-in element, in particular a piercing nut (2), which has a heat part (6) having a head support (8) for placing on a component (22) and a piercing collar (10) having an end-side cutting edge (24). An undercut (26) is formed between the piercing collar (10) and the head support (8). A peripheral displacing ridge (16) is formed adjacent to the piercing collar (10) on the head support (8), which displacing ridge is adjoined in the radial direction (14) by a further outer region (18) of the head support (8), which outer region is set back from the displacing ridge (16) in the longitudinal direction (4). When the press-in connection is formed, material is pressed from the top side (28) of the component (22) into the undercut (26) by means of the displacing ridge (16). The bottom (34) of the component (22) is preferably not deformed. Fig.