Ball Surface Compression Using Smooth Contact Pressing

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Solution Overview

Problem

Current methods for imparting compressive stress to spherical balls, such as tumbling and peening, are noisy and difficult to control, leading to uneven stress distribution and potential damage to the surface finish, necessitating reworking.

Innovation Solution

An apparatus with a smooth, flat surface and a drive system that moves a harder surface in contact with the balls to apply compressive force uniformly across their surfaces, allowing for controlled stress distribution without noise and surface damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If tumbling operation is used to impart compressive stress to balls, then compressive stress is distributed across the ball surface, but the operation produces excessive noise and makes it difficult to achieve uniform stress distribution

Engineering Contradiction:
Improvecompressive stress distributionVSAvoidnoise
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the traditional tumbling mechanical system with a controlled pressing system using a press plate and spherical indentors. Instead of relying on random ball-to-ball impacts in a rotating drum, the invention applies controlled compressive forces through mechanical pressing, significantly reducing noise while maintaining effective stress imparting to the ball surfaces

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces spherical indentors as intermediary elements between the press plate and the balls. These indentors concentrate and distribute the compressive force uniformly across multiple ball surfaces, achieving uniform stress distribution without the chaotic motion and noise characteristic of tumbling operations

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stress or pressure

If peening operation is used to accelerate balls for impact, then compressive stress is imparted to ball surfaces, but the operation is very noisy and provides limited control over surface hardness and stress profile

Engineering Contradiction:
Improvecompressive stressVSAvoidcontrol over surface hardness and stress profile
Core Design Contradiction:
Stress or pressureVSEase of operation

Solution Approach 1:

The patent replaces the high-velocity impact mechanism of peening with a controlled compression system. Instead of accelerating balls to high speeds for impact, the invention uses a press plate with spherical indentors to apply controlled compressive forces directly to the ball surfaces, enabling precise control over stress profile and surface hardness while eliminating the excessive noise of peening operations

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables control over stress parameters by varying the pressing force, contact time, and indinator geometry. This allows precise adjustment of surface hardness and stress profile characteristics, providing the ease of operation and control that was limited in traditional peening methods

Inventive Principle:
Principle #35Parameter changes

3Stress or pressure

If tumbling or peening operations are used to impart compressive stress, then stress is distributed across ball surfaces, but the surface finish is damaged requiring reworking

Engineering Contradiction:
Improvecompressive stress distributionVSAvoidsurface finish quality
Core Design Contradiction:
Stress or pressureVSManufacturing precision

Solution Approach 1:

The patent replaces the high-impact mechanical systems of tumbling and peening with a controlled compression system using smooth spherical indentors. This substitution applies stress through gradual compression rather than sudden impacts, imparting compressive stress to ball surfaces while preserving surface finish quality and eliminating the need for reworking

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 apparatus effectively imparts compressive residual stress uniformly across the surface of spherical balls, reducing noise and providing greater control over the stress profile, independent of ball mass, resulting in a more efficient and quieter process.

Implementation Method 1

imparting compressive residual stress to at least a surface portion of a first plurality of balls

Methodology Applied
Scientific EffectCompressive stress: Compression

Implementation Method 2

move the first body relative to the second body at a substantially fixed distance from the second body or to move the second body relative to the first body at a substantially fixed distance from the first body

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP3162494B1Apparatus for producing compressive residual stress in balls
Publication Date: 2022.08.03 AB SKF SKF PATENT DEPARTMENT
  • EP3162494B1 patent drawingFigure 1~3
  • EP3162494B1 patent drawingFigure 4~6
  • EP3162494B1 patent drawingFigure 5

AI summary

An apparatus (10) for imparting compressive residual stress to at least a surface portion of a first plurality of balls (16) includes a first body (12) having a first surface (14), the first surface including a smooth contact portion, the smooth contact portion being substantially flat or convex and having a surface hardness greater than or equal to the initial surface hardness of the balls (16). The apparatus also includes a second body (20) having a second surface (22), the first surface overlying the second surface, and at least one drive (24) operably connected to the first body (12) or to the second body (20) and configured to move one of the first and second bodies relative to the other body at a substantially fixed distance, the at least one drive also being configured to move the first body toward the second body with a force or to move the second body toward the first body with the force.