Open-Center Slewing Bearing With Solid Lubricant Sealing

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Solution Overview

Problem

Large slewing bearings face issues with premature wear and lubrication challenges due to high forces, bending moments, and torsion, leading to leakage and maintenance problems, especially in center-free designs where conventional lubrication methods are ineffective.

Innovation Solution

The use of a solid lubricant with a polymer matrix that fills the bearing gap, releasing lubricant under load and reabsorbing it when pressure decreases, combined with longitudinal groove-like lubricant pockets in the raceways and a solid lubricant filling the bearing gap, providing continuous lubrication and sealing without the need for conventional lubricant supply systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional lubrication systems with lubricant supply and sealing systems are used, then lubrication can be maintained, but the system becomes complex and prone to leakage and maintenance issues

Engineering Contradiction:
Improvelubrication reliabilityVSAvoidsealing system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex sealing system and lubricant supply system from the bearing structure. Instead of using conventional seals and lubricant delivery mechanisms, the invention uses a solid lubricant composition that is directly applied to the raceway surfaces, removing the need for separate sealing and supply systems while maintaining reliable lubrication.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The solid lubricant composition performs multiple functions simultaneously: it provides lubrication, seals the bearing gap, and prevents contaminant ingress. This multi-functional approach replaces the need for separate sealing systems and lubricant supply systems, simplifying the overall device while improving reliability.

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

2Reliability

If high lubricant pressure is used to ensure lubricant reaches all bearing areas, then lubrication coverage improves, but leakage increases

Engineering Contradiction:
Improvelubrication coverageVSAvoidlubricant leakage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the physical state of the lubricant from liquid to solid, and modifies the delivery mechanism from pressure-driven injection to load-driven release. The solid lubricant composition is contained in pockets and released under load through contact between rolling elements and the raceway, eliminating the need for high pressure and preventing leakage while ensuring complete lubrication coverage.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the bearing operates at low speeds or remains stationary, then the application requirements are met, but uniform lubrication becomes difficult

Engineering Contradiction:
Improveoperating condition adaptabilityVSAvoidlubrication uniformity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a dynamic lubrication mechanism where the solid lubricant is released based on load conditions rather than requiring continuous motion or high speed operation. The lubricant pockets are activated when rolling elements contact the raceway under load, ensuring uniform lubrication distribution regardless of operating speed or stationary periods.

Inventive Principle:
Principle #15Dynamics

4Reliability

If sealing systems are used to prevent lubricant leakage, then lubricant retention improves, but dirt ingress prevention is compromised and maintenance requirements increase

Engineering Contradiction:
Improvelubricant retentionVSAvoiddirt ingress
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The solid lubricant composition serves as both the lubricant and the sealing medium. By filling the bearing gap with this composition, the system simultaneously retains lubricant and prevents dirt ingress, eliminating the need for separate sealing systems and reducing maintenance requirements.

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

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

This solution maintains effective lubrication and sealing, reducing maintenance and leakage issues, as the solid lubricant is self-sustaining and prevents dirt ingress, ensuring the bearing remains operational under high loads and low speeds.

Implementation Method 1

a solid lubricant comprising a polymer matrix and a lubricant embedded within it, wherein the bearing gap is completely filled with the solid lubricant

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

the solid lubricant is compressible and/or deformable and/or expandable, so that when the solid lubricant is compressed by pressure applied to it via the rolling elements and/or raceways

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

the bearing gap is completely filled with the solid lubricant... to prevent dirt such as dust or other harmful media from entering the bearing gap from the outside

Methodology Applied
Scientific EffectPhysical Containment: Physical Containment

Data Source

PatentEP3759367B1Large rolling bearing
Publication Date: 2023.11.15 LIEBHERR COMPONENTS BIBERACH GMBH
  • EP3759367B1 patent drawingFigure 1
  • EP3759367B1 patent drawingFigure 2
  • EP3759367B1 patent drawingFigure 3

AI summary

The invention relates to a large rolling bearing, more particularly an open-center large rolling bearing, comprising two concentric running rings, between which a plurality of rolling elements is provided in a bearing gap, which rolling elements roll on at least two raceways. More particularly, the bearing gap between the running rings and/or between at least one running ring and the rolling elements is at least partially filled with a solid lubricant, which comprises a polymer matrix and a lubricant embedded therein.