Meandering Retaining Disc Edges for Low-Chip Axial Assembly

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Solution Overview

Problem

Existing retaining disks for axially securing components in cylindrical cavities or on shafts often suffer from sharp edges that can lead to chip formation and reduced functionality, requiring high assembly effort and potentially resulting in crack formation and failure due to notch effects.

Innovation Solution

A retaining disk design featuring a meandering outer and inner edge, with wave-like troughs and crests that eliminate sharp edges, providing a secure supporting effect with reduced push-in force and increased rigidity, allowing for reliable assembly and improved functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the retaining disk has straight outer and inner edges, then the assembly process is simple, but sharp edges form chips that reduce functionality and require laborious removal

Engineering Contradiction:
Improveassembly simplicityVSAvoidchip formation
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies curvature by designing the outer and inner edges of the retaining disk to meander between the outer and inner circles, creating wave-like contours instead of straight edges. This curvature eliminates sharp edges that would otherwise form chips during assembly, while the meandering path maintains manufacturing simplicity and structural integrity

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If the retaining disk uses a meandering edge design, then chip formation is reduced and reliability is improved, but the structural complexity increases

Engineering Contradiction:
Improvechip formation resistanceVSAvoidedge geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The meandering edge geometry creates a wave-like pattern that eliminates sharp corners while maintaining a relatively simple overall structure. The curvature is achieved through a controlled meandering path between two circles, which reduces chip formation without requiring complex multi-component designs

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent combines the outer edge and inner edge into a single meandering contour that alternates between the outer and inner circles. This unified meandering design simultaneously provides chip-free edges and structural rigidity, avoiding the need for separate components

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the retaining disk has a meandering edge design, then assembly effort is reduced, but the push-in force required during assembly increases

Engineering Contradiction:
Improveassembly effortVSAvoidpush-in force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The meandering edge design with its wave-like contours reduces assembly effort by eliminating sharp edges that would otherwise require high forces to push through. The curved path allows for more gradual deformation and insertion, distributing the assembly force more evenly

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Strength

If the retaining disk uses conventional straight edges, then the structure is rigid, but the sharp edges create notch effects that lead to crack formation

Engineering Contradiction:
Improvestructural rigidityVSAvoidcrack formation resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The meandering edge design replaces sharp straight edges with curved contours that meander between the outer and inner circles. This curvature eliminates stress concentration points that would otherwise lead to crack formation, while the wave-like structure maintains structural rigidity through its distributed geometry

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 meandering edge design ensures a secure hold without sharp edges, reducing chip formation and assembly effort, while maintaining sufficient rigidity and elasticity for effective axial fixation, thus enhancing the reliability and longevity of the retaining disk.

Implementation Method 1

The outer diameter of the retaining disc in the relaxed state, which corresponds to the diameter of said outer circle, is oversized compared to the free inner diameter of the cylinder opening of the cavity, so that the retaining disc is radially elastically tensioned when it is inserted coaxially

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

Due to the fact that the retaining edge, in this case the outer edge, is arranged inclined against the direction of insertion on the retaining disc relative to the longitudinal axis, i.e. at an angle, a barb-like arrangement is formed, so that an axial supporting force acting on the retaining element counter to the direction of insertion ensures that the holding edge is pressed even more strongly in the radial direction against the inner wall

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP3601817B1Retaining disc
Publication Date: 2023.07.05 THYSSENKRUPP PRESTA AG
  • EP3601817B1 patent drawingFigure 1~3
  • EP3601817B1 patent drawingFigure 4~6
  • EP3601817B1 patent drawingFigure 7~9

AI summary

The invention relates to a retaining disc (7, 8) for axially securing a component in a cylindrical cavity or on a cylindrical shaft. The retaining disc (7, 8) has a protruding retaining portion (71, 81) with an end face (750, 850), and the end face (750, 850) is delimited by an outer edge (75, 85) and an inner edge (78, 88). The outer edge (75, 85) is inscribed in an outer circle (AK) with a first center (M1), and an inner circle (IK) with a second center (M2) is inscribed within the inner edge (78, 88). The first center (M1) and the second center (M2) lie on an axis (A), and the retaining portion (71, 81) is inclined towards the axis (A) at least in the region of the end face (750, 850). The aim of the invention is to allow a reliable assembly with improved functionality. According to the invention, this is achieved in that the outer edge (75, 85) and/or the inner edge (78, 88) meanders between the outer circle (AK) and the inner circle (IK) so as to project onto a projection plane (P1, P2) which is orthogonal or parallel to the axis (A).