Textured Deep Rolling Tool for Contact Stress and Surface Bonding

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Solution Overview

Problem

Existing deep rolling tools are expensive, complex, and inefficient, particularly for processing complex geometries, and lack effective methods to control contact stress and prevent surface damage during the deep rolling process.

Innovation Solution

A system comprising a roller tool with a textured roller and a dynamic force controller, integrated with a robotic arm, to apply controlled compressive stresses and imprint surface textures, ensuring consistent contact stress and preventing collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a ball bearing is used in hydraulic burnishing tools for complex geometries, then processing precision is improved, but device complexity and cost increase, and productivity decreases

Engineering Contradiction:
Improveprocessing precisionVSAvoidproduction time and throughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The roller tool is segmented into a roller body with circumferential grooves that create discrete texture patterns on the workpiece surface. This segmentation allows the roller to process larger surface areas simultaneously compared to a ball bearing, improving productivity while maintaining precision through the controlled groove geometry

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The roller tool copies the groove pattern from the roller surface to the workpiece surface, creating a replicated texture that improves coating bonding and tribological properties. This copying mechanism eliminates the need for complex hydraulic control systems while achieving consistent surface treatment results

Inventive Principle:
Principle #26Copying

2Strength

If hydraulic pressure is increased to improve contact stress control, then material property improvement is enhanced, but device complexity and maintenance requirements increase

Engineering Contradiction:
Improvecompressive residual stressVSAvoidhydraulic pressure control system
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The hydraulic pressure control system is replaced with a mechanically actuated roller tool that applies contact stress through direct mechanical force. The roller is driven by a motor and applies controlled pressure through its weight and mechanical actuation, eliminating complex hydraulic systems while maintaining effective contact stress for inducing compressive residual stresses

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

Solution Approach 2:

The roller tool is designed to self-regulate contact stress through its mechanical design, including the roller pressure control system that automatically maintains appropriate contact force without requiring external hydraulic pressure control. The roller naturally adapts to the workpiece surface geometry while maintaining consistent contact stress

Inventive Principle:
Principle #25Self-service

3Duration of action of stationary object

If contact stress is increased to improve material properties, then fatigue life is enhanced, but surface damage risk increases

Engineering Contradiction:
Improvefatigue lifeVSAvoidsurface damage
Core Design Contradiction:
Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The contact stress parameters are optimized by controlling roller pressure, speed, and groove geometry to achieve the desired compressive residual stress depth and magnitude. By carefully selecting groove depth, width, and spacing, the system induces beneficial compressive stresses at controlled depths without creating excessive surface stresses that would cause damage

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The roller tool design incorporates pressure control mechanisms that prevent excessive contact stress before it can cause surface damage. The mechanical design includes features that limit maximum contact pressure and distribute loads evenly, cushioning against potential surface damage while ensuring sufficient stress induction for fatigue life improvement

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If a textured roller is used to imprint surface texture, then coating bonding and tribological properties are improved, but manufacturing complexity increases

Engineering Contradiction:
Improvecoating bondingVSAvoidroller manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The roller grooves are pre-formed during roller manufacturing using conventional machining processes such as milling or grinding. This preliminary creation of the texture pattern allows the roller to immediately impart the desired surface texture during operation without requiring complex real-time texture generation systems

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The roller surface is designed with localized groove features at specific locations and orientations to create the desired texture pattern on the workpiece. By concentrating the texturing function in the roller groove geometry rather than requiring complex roller construction, the manufacturing process is simplified while achieving the local surface quality needed for coating bonding

Inventive Principle:
Principle #3Local quality

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 system enhances fatigue life and coating bonding by inducing residual compressive stresses while maintaining a smooth surface finish, improving production efficiency and reducing defects.

Implementation Method 1

The Deep Rolling process uses a roller to roll the surface under controlled load & speed. The rolling pressure induces a deep layer of compressive residual stress.

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

A textured roller to imprint a predetermined texture on surfaces intended to be deep rolled

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

This can improve coating bonding or tribological properties

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4628256A1Robotic deep rolling tool design for surface texturing to control friction and coating bonding
Publication Date: 2025.10.08 RTX CORP
  • EP4628256A1 patent drawingFigure 1
  • EP4628256A1 patent drawingFigure 2
  • EP4628256A1 patent drawingFigure 3

AI summary

A system for deep rolling a workpiece including a roller tool comprising an adaptor plate proximate an adapter end; an arm attached to the adaptor plate, the arm comprising an adapter end proximate the adaptor plate, the arm comprising a roller end opposite the adapter end, the arm comprising a midspan portion between the adapter end and the roller end; and a roller disk joined to the roller end, the roller disk including a surface feature configured to contact the workpiece and imprint a surface texture on a workpiece surface.