Rolling Bearing Raceway Correction for Uneven Load Sectors

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Solution Overview

Problem

Rolling bearings in large or highly loaded structures, such as cranes, experience premature wear due to twisting and angular misalignment of raceways under axial, radial, and tilting loads, especially when subjected to uneven load distribution and inhomogeneous adjacent structures, leading to edge wear and reduced load-bearing capacity.

Innovation Solution

The raceway correction is varied across the circumference of the race rings, with different adjustments in angular sectors to match expected loads, combining angular and shape corrections to ensure even load distribution and contact between rolling elements and raceways, and optionally incorporating rolling element and connection surface corrections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a constant raceway correction is applied across the entire circumference, then the rolling elements can fit snugly against the raceways under uniform load, but the load distribution becomes uneven when subjected to bending moments and tilting forces, causing edge wear

Engineering Contradiction:
Improvecontact quality between rolling elements and racewaysVSAvoidedge wear and uneven load distribution
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different raceway corrections in different angular sectors rather than a uniform correction across the entire circumference. Specifically, a first angular sector has a raceway correction with a first correction angle, while a second angular sector has a different correction angle. This local differentiation allows each sector to be optimized for its specific load conditions, preventing edge wear while maintaining good contact quality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The raceway is divided into multiple angular sectors, each with its own correction parameters. This segmentation allows the bearing to handle non-uniform load distributions caused by bending moments and tilting forces, as each sector can be independently optimized for the load conditions it experiences.

Inventive Principle:
Principle #1Segmentation

2Strength

If wide rollers are used to increase contact area and reduce surface pressure, then the load-bearing capacity increases, but the bearing becomes critically sensitive to raceway misalignment, causing edge loading

Engineering Contradiction:
Improveload-bearing capacityVSAvoidsensitivity to misalignment
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

By applying different correction angles in different angular sectors, the patent allows wide rollers to maintain full-face contact in each sector despite raceway misalignment. The local optimization compensates for the misalignment effects, enabling the use of wide rollers for increased load capacity without the critical sensitivity to misalignment.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the bearing rings are made smaller to fit space constraints, then the bearing can be installed in centerless applications, but the area moments of inertia of the races are limited, reducing stiffness

Engineering Contradiction:
Improveinstallability in centerless applicationsVSAvoidstiffness
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent compensates for the reduced stiffness of smaller bearing rings by optimizing the raceway geometry locally in different sectors. The varied corrections allow the smaller rings to better accommodate load-induced deformations, effectively maintaining performance despite reduced dimensions.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3956577B1Rolling bearing and material transfer- or construction machine having such a rolling bearing
Publication Date: 2025.09.10 LIEBHERR COMPONENTS BIBERACH GMBH
  • EP3956577B1 patent drawingFigure 1
  • EP3956577B1 patent drawingFigure 2
  • EP3956577B1 patent drawingFigure 3

AI summary

The present invention relates to a rolling bearing having two bearing rings which are concentric with one another, are supported on one another rotatably with respect to each other by means of at least one row of rolling elements and have bearing races for the rolling elements of the at least one row of rolling elements. The invention further relates to a material transfer- or construction machine, such as a crane or cable excavator, having such a rolling bearing. The invention proposes providing different bearing race corrections in different angular sectors of the bearing rings and/or providing the bearing race correction only in a fraction of the circumference of the bearing rings.