Copper Alloy Thrust Bearing Cage Protrusions

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Solution Overview

Problem

Conventional machined cages for thrust ball bearings face issues with ball retention during handling and assembly, particularly in larger sizes, due to high workloads, poor productivity, and non-uniformity in swaging, which are not adequately addressed by resin or steel plate cages.

Innovation Solution

A copper alloy machined cage with protruding portions on the inner and outer diameter sides of the pockets, which are elastically or elastic-plastically deformable, to prevent ball ejection and facilitate easier insertion, defined by specific dimensions and configurations to ensure secure ball retention without compromising the bearing's performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If swaging is performed to prevent ball falling out, then ball retention is improved, but work load and time increase, and productivity deteriorates

Engineering Contradiction:

Improveball retentionVSAvoidproductivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The protruding portions are formed on the cylindrical surface before ball insertion, creating preliminary mechanical barriers that guide and retain balls during assembly and handling, eliminating the need for post-assembly swaging operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention extracts the ball retention function from the swaging process and implements it through integrated protruding portions on the cage structure, separating the retention mechanism from the assembly process

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If swaging is performed to prevent ball falling out, then ball retention is improved, but non-uniformity of swaging amount and deterioration of pocket shape accuracy occur

Engineering Contradiction:

Improveball retentionVSAvoidpocket shape accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The protruding portions are pre-formed on the cylindrical surface with precise dimensions and positions, ensuring uniform ball retention characteristics without the variability introduced by manual or press swaging operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protruding portions are strategically positioned on the cylindrical surface at specific locations to provide localized ball retention functionality while preserving the overall pocket shape and machining precision

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If resin cage is used for large outer diameter bearings, then manufacturing cost is reduced, but molding and strength become problematic

Engineering Contradiction:

Improvemanufacturing costVSAvoidstrength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The invention combines the cost advantage of resin material with the structural strength requirements by using resin as the base material while incorporating reinforcing elements or design features that enhance strength for large outer diameter bearings

Inventive Principle:

Principle #40Composite materials

4Strength

If steel plate pressed cage is used for large outer diameter bearings, then strength is improved, but rotating accuracy and high-speed properties deteriorate

Engineering Contradiction:

ImprovestrengthVSAvoidrotating accuracy and high-speed properties

Core Design Contradiction:

StrengthVSSpeed

Solution Approach 1:

The invention modifies the structural parameters of the cage by incorporating protruding portions with specific dimensions and configurations that optimize the balance between strength and rotational performance, enabling the cage to maintain structural integrity while achieving better rotating accuracy and high-speed properties

Inventive Principle:

Principle #35Parameter changes

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 solution enhances ball retention and insertion ease while maintaining the performance of copper alloy machined cages, reducing processing complexity and costs by eliminating the need for swaging, thus improving productivity and accuracy.

Implementation Method 1

the protruding portions are either elastically deformable or elastic-plastically deformable by the ball during insertion of the ball into the pocket

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the protruding portions are either elastically deformable or elastic-plastically deformable by the ball during insertion of the ball into the pocket

Methodology Applied

Scientific EffectElastic-plastic deformation: Plasticity

Data Source

PatentUS10228021B2Machined cage for thrust ball bearing, design method of the same, and thrust ball bearing including the cage

Publication Date: 2019.03.12 NSK LTD

AI summary

In a copper alloy machined cage for a thrust ball bearing, an inside surface of a pocket includes a cylindrical surface, a support surface which is continuous with the cylindrical surface and contacts a ball in an axial direction, and two protruding portions which are formed at an equal interval in a circumferential direction of the pocket, at a ball insertion side of the pocket which is opposite to the support surface in the axial direction and protrude from the cylindrical surface. The protruding portions prevent falling out of the ball from a ball insertion side opening of the pocket and are either elastically deformed or elastic-plastically deformed by the ball during insertion of the ball into the pocket.