Friction-Welded Connection Element With Convex Tip to Prevent Chips

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Solution Overview

Problem

Existing friction welding technologies face challenges in reducing processing time and material waste, such as increased axial force and metal chip generation, while achieving strong connections between components.

Innovation Solution

A connecting element with a shank end face featuring a convex, blunt shape and surface structures like elevations and depressions, which increases friction during welding, reducing material waste and processing time by preventing chip formation and enhancing heat generation for a stronger bond.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a convex projection with cutting edge or annular edge is used on the shaft end face, then penetration of the joining element into the component is facilitated, but metal chips are generated during friction welding

Engineering Contradiction:
Improvepenetration capabilityVSAvoidmetal chip generation
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent applies curvature by replacing sharp cutting edges with a rounded convex projection having a radius R1. This spherical curvature allows the joining element to penetrate the component through rolling contact rather than cutting, thereby facilitating penetration while preventing metal chip generation. The rounded shape distributes contact forces and avoids stress concentration that would otherwise cause material removal.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent converts the potentially harmful cutting action into a beneficial rolling friction action. By designing the convex projection with a rounded shape instead of a sharp edge, the friction that would normally cause chip generation is transformed into the primary mechanism for penetration and heat generation. The frictional heat directly contributes to the friction welding process while the rolling motion enables penetration without material removal.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Manufacturing precision

If a thread-like non-circular profile is used to guide displaced material, then material flow is controlled, but processing time increases due to higher axial force requirements

Engineering Contradiction:
Improvematerial flow controlVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the geometric parameters of the shaft end face by introducing specific curvature radii (R1 for the convex projection, R2 for the concave region) and dimensional relationships (L1, L2, D1, D2). These parameter optimizations allow material flow to be controlled through the friction and pressure distribution created by the rounded geometry, rather than requiring complex thread-like profiles. The optimized parameters enable efficient material displacement with reduced axial force requirements.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a convex projection with sharp edges is used for penetration, then joining element insertion is easier, but joint strength is insufficient due to material waste

Engineering Contradiction:
Improveinsertion easeVSAvoidjoint strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies curvature by replacing sharp cutting edges with a rounded convex projection having a radius R1. This spherical curvature allows the joining element to penetrate the component through rolling contact rather than cutting, thereby facilitating penetration while preventing metal chip generation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent converts the potentially harmful cutting action into a beneficial rolling friction action. By designing the convex projection with a rounded shape instead of a sharp edge, the friction that would normally cause chip generation is transformed into the primary mechanism for penetration and heat generation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 a more efficient friction welding process with reduced material waste and increased connection strength, as the convex shape and surface features enhance friction, heat input, and bonding efficiency without generating flying chips.

Implementation Method 1

The connecting element (10) is rotated about a longitudinal axis (10.1) of the connecting element (10) in order to permanently join at least two components (12.1, 12.2) to one another by friction welding

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The shaft end face (10.21) has a convex envelope (10.22) with an obtuse slope and includes elevations (10.23) and depressions (10.24) that increase friction during welding

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3717172B1Connection element for connecting at least two components in a non-releasable manner, and composite assembly
Publication Date: 2023.06.14 ARNOLD UMFORMTECHN
  • EP3717172B1 patent drawingFigure 1~2
  • EP3717172B1 patent drawingFigure 3
  • EP3717172B1 patent drawingFigure 4~7

AI summary

The invention relates to a connection element (10) for connecting at least two components (12.1, 12.2) in a non-releasable manner by means of friction welding while rotating the connection element (10) about a longitudinal axis (10.1) of the connection element (10). The connection element (10) comprises: - a shaft (10.2 - 10.4) which is formed along the longitudinal axis (10.1) and comprises a shaft end (10.2) at a free end of the shaft (10.2 - 10.4) for penetrating at least one component (12.1), and - a head (10.5), which is connected to the shaft (10.2 - 10.4), for transmitting a torque about the longitudinal axis (10.1) from a rotary tool to the shaft (10.2 - 10.4), wherein the shaft end (10.2) has a shaft end face (10.21) which has a convex envelope (10.22) that progresses in a blunt manner.