Ceramic Bearing Ball Geometry to Reduce Polishing Chipping

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Solution Overview

Problem

Ceramic bearing balls are prone to chipping during machining due to their brittle nature, especially at the corners of the band-shaped portions, which are prone to impact and cause damage to both the material and the machining tools.

Innovation Solution

The ceramic bearing ball material features a band-shaped portion with a width of 0.5-4.0 mm and rounded shoulders with a radius of curvature of 0.02 mm or more, and a concave outer periphery with a radius of curvature of 5-30 mm, designed to minimize contact points during polishing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If press molding is used to manufacture ceramic bearing balls, then the manufacturing efficiency is improved, but the corners of the band-shaped portion are prone to chipping due to impact

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidchipping resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention applies curvature to the corners of the band-shaped portion by forming an R section with a radius of curvature of 0.02 mm or more. This rounded geometry eliminates sharp corners that are prone to chipping during machining and usage, while maintaining the overall spherical shape and band-shaped structure necessary for bearing ball functionality.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Ease of manufacture

If the band-shaped portion has sharp corners, then the machining process is simpler, but the ceramic material is prone to chipping during polishing

Engineering Contradiction:

Improvemachining simplicityVSAvoidchipping during polishing

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The corners of the band-shaped portion are rounded with an R section having a radius of curvature of 0.02 mm or more. This curvature transformation eliminates the sharp corners that cause chipping during polishing while maintaining ease of manufacture through the molding process.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Strength

If the outer periphery is convex, then the structural strength is improved, but the polishing tools experience excessive wear and damage

Engineering Contradiction:

Improvestructural strengthVSAvoidpolishing tool lifespan

Core Design Contradiction:

StrengthVSDuration of action of stationary object

Solution Approach 1:

The invention inverts the conventional convex outer periphery design by making it concave. This inversion reduces the contact area and impact force between the ceramic ball and polishing tools, thereby extending tool lifespan while maintaining sufficient structural strength through the concave geometry.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP4269022B1Ceramic ball material, ceramic ball manufacturing method using same, and ceramic ball

Publication Date: 2025.07.30 NITERRA MATERIALS CO LTD

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AI summary

A ceramic ball material according to the present embodiment includes a spherical portion, and a band-shaped portion formed over a circumference of a surface of the spherical portion. The band-shaped portion has a width in a range of 0.5 mm or more and 4.0 mm or less, both shoulders of which are provided with an R section having a radius of curvature of 0.02 mm or more. Any one of aluminum oxide, silicon nitride, boron nitride, and zirconium oxide is used as the ceramic.