Segmented Bearing Retaining Cage for Axial Misalignment

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Solution Overview

Problem

Bearing units with retaining cages deform under high axial loads or misalignments, causing the tenons to lose their ability to hold balls, leading to unwanted disassembly.

Innovation Solution

A bearing unit with a retaining cage composed of movable sectors connected via dovetail joints, allowing axial movement to accommodate misalignments and loads while maintaining the cage's integrity, and an annular elastic element for sector positioning and return.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a continuous base frame retaining cage is used, then the cage provides structural rigidity to hold balls spaced apart, but the cage deforms under high axial loads or misalignments causing tenons to lose ball retention

Engineering Contradiction:

Improvestructural rigidityVSAvoidball retention

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The continuous base frame is divided into multiple modular sectors that can move independently relative to each other. Each sector contains tenons for ball retention, and the sectors are connected through engagement portions that allow axial movement while maintaining circumferential positioning. This segmentation enables the cage to accommodate deformation from axial loads and misalignments without losing ball retention capability.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If the retaining cage is made from a single continuous base frame, then manufacturing is simplified, but the cage cannot accommodate axial movement without deforming

Engineering Contradiction:

Improvecage manufacturingVSAvoidaxial movement accommodation

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The cage is manufactured as multiple separate sectors that are subsequently assembled together. Each sector can be independently manufactured with precise tenon and cavity features, then assembled into the complete cage. The engagement portions between sectors provide the necessary axial movement capability while maintaining overall cage integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The engagement portions between adjacent sectors are designed to allow axial movement of sectors relative to each other while preventing radial separation. This dynamic capability enables the cage to adapt to axial loads and misalignments during operation, with sectors moving independently to accommodate deformation without compromising ball retention.

Inventive Principle:

Principle #15Dynamics

3Stability of the object's composition

If the cage structure is made rigid to maintain ball positioning, then ball spacing is maintained, but the cage cannot withstand high axial loads without deformation

Engineering Contradiction:

Improveball spacingVSAvoidaxial load resistance

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

By dividing the cage into multiple rigid sectors connected through flexible engagement portions, each sector maintains its structural integrity and ball positioning stability, while the connection between sectors allows axial movement to absorb applied loads. This creates a hybrid structure combining local rigidity with global flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The engagement portions between sectors function as flexible elements that allow controlled axial movement. These portions are designed with specific geometric features that permit movement in the axial direction while maintaining constraint in radial directions, enabling the rigid sectors to move relative to each other under load without compromising ball retention.

Inventive Principle:

Principle #30Flexible shells and thin films

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

Prevents deformation and disassembly by allowing axial movement of individual sectors, maintaining ball retention under high loads and misalignments, and enabling sector replacement without altering the cage's assembly process or dimensions.

Implementation Method 1

an annular elastic element (60) extending inside the seat (53) of each movable sector (50)... said elastic element (60) being configured to store and release elastic energy to move said movable sectors (50) between engaged and disengaged positions

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20250012323A1Bearing unit with retaining cage

Publication Date: 2025.01.09 AB SKF SKF PATENT DEPARTMENT

AI summary

A bearing unit (30) has a central axis (X) of rotation and a retaining cage (40) for a plurality of rolling bodies (34) interposed between a radially outer ring (31) and a radially inner ring (33). The retaining cage (40) has a plurality of movable sectors (50) that are made of polymeric material, are identical to one another, and are arranged circumferentially adjacent to one another. Each movable sector (50) has at the ends a first engagement portion (51) and a second engagement portion (52) that are configured to define a dovetail joint between the first engagement portion (51) of a first movable sector (50′) and the second engagement portion (52) of a second movable sector (50″), circumferentially adjacent to the first movable sector (50′) to create a circumferential and radial constraint as well as a degree of axial freedom between the two movable sectors (50′, 50″).