Split Inner Ring Mounting with Rolling Ring Preload Control

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Solution Overview

Problem

Existing methods for fastening split inner rings on shafts, such as in rack and pinion steering systems, face challenges in controlling and limiting bearing tension, leading to negative influences on running behavior like friction and feel.

Innovation Solution

A method involving a rolling ring that indirectly limits the axial movement of the inner ring through a compensating element, such as a spring, allowing for controlled preload adjustment without high pressing forces, replacing traditional screw connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a screw connection is used to fasten the split inner ring to the shaft, then the inner ring is securely fastened, but the preload becomes too high and difficult to control, causing negative effects on bearing running behavior

Engineering Contradiction:
Improvefastening securityVSAvoidpreload
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

A rolling ring is introduced as an intermediary element between the inner ring and the shaft. The rolling ring distributes the fastening forces over a larger area and provides a more favorable force transmission path, reducing the concentrated preload on the inner ring while maintaining secure fastening. The rolling contact mechanism allows for controlled force application during the mounting process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The traditional screw connection (threaded mechanical fastening) is replaced with a rolling ring mounting system that uses radial rolling forces to secure the inner ring. This substitution eliminates the need for axial screw threads and nut fastening, replacing them with a rolling contact mechanism that applies forces in a more controlled manner during the mounting process.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a screw connection is used to fasten the split inner ring, then the inner ring is secured, but the preload control becomes difficult and bearing running behavior deteriorates

Engineering Contradiction:
Improvefastening securityVSAvoidpreload control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The rolling ring serves as a mediator that provides controlled force application during mounting. The rolling contact mechanism inherently limits the maximum forces that can be applied, preventing excessive preload while ensuring adequate fastening security. This intermediate element acts as a force-limited coupling between the mounting tool and the inner ring.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mounting process parameters are changed from axial screw fastening to radial rolling forces. This parameter change allows for better control of the applied loads, as the rolling ring can only transmit forces through its rolling contact, providing natural limits on the maximum preload that can be applied to the inner ring.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If pressing forces are used to fasten the rolling ring, then the inner ring is secured, but the pressing forces required are too high

Engineering Contradiction:
Improvefastening securityVSAvoidpressing forces
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The rolling ring utilizes curved rolling surfaces that convert axial pressing forces into radial rolling forces. This curvature allows the rolling elements to roll along the tapered or curved surfaces of the rolling ring, mechanically advantageously distributing the applied forces and reducing the total pressing force required compared to direct axial pressing.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

Direct axial pressing is replaced with a rolling contact mechanism. The rolling elements transform the pressing motion into rolling motion, which provides mechanical advantage through the rolling contact geometry. This substitution reduces the required pressing forces by utilizing the rolling friction advantage over sliding friction and the mechanical leverage provided by the rolling ring's geometry.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method securely fastens the inner ring while maintaining a simple and cost-effective process, ensuring controlled preload and minimizing impairment to the bearing's function.

Implementation Method 1

rolling in a rolling ring (16) in such a way that the rolling ring (16) indirectly limits a movement of the inner ring (13) in an axially external direction on the shaft (10)

Methodology Applied
Scientific EffectRolling:

Implementation Method 2

This deforms the rolling ring in such a way that it indirectly limits movement in the axially outward direction of the inner ring via a compensating element

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 3

The compensating element is, in particular, a spring element, e.g., a wave spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4008919B1Method for mounting a split inner ring on a shaft
Publication Date: 2023.12.27 VOLKSWAGEN AG
  • EP4008919B1 patent drawingFigure 1
  • EP4008919B1 patent drawingFigure 2~3
  • EP4008919B1 patent drawingFigure 4~5

AI summary

A method for fastening a split inner ring (13) to a shaft (10) is proposed, comprising rolling in a rolling ring (16) such that the rolling ring directly or indirectly limits a movement of the inner ring in an axially outward direction (22).