Spring-Loaded Deep Rolling Tool With Load Cell

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Solution Overview

Problem

Existing deep rolling tools are expensive, complex, and inefficient for processing complex geometries and thin walls, with limited adaptability to widely available machine tools, and lack precise control over contact stress, which can lead to material damage or inadequate property improvement.

Innovation Solution

A spring-loaded deep rolling tool assembly with a rotatable roller disk and load cell for precise force measurement and application, allowing customizable contact stress and integration with robotic arms for complex geometry access, enabling efficient processing of nonplanar surfaces with real-time load monitoring and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a ball bearing is used in known LPB tools for complex geometries, then precision is improved, but production time is increased and cost is increased

Engineering Contradiction:
ImproveprecisionVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces expensive, precision ball bearings with a simpler, more economical roller element that can be easily replaced. The roller has a larger surface area that can be worn or damaged, but the overall tool cost is reduced and replacement is simpler, improving productivity without sacrificing necessary precision for the application.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses a roller with a curved or cylindrical working surface instead of a spherical ball bearing. This curvature provides sufficient contact area for precision work while allowing for easier manufacturing, lower cost, and faster replacement, thus resolving the contradiction between precision and production time.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Manufacturing precision

If a ball bearing is used in known LPB tools, then precision is improved, but cost is increased

Engineering Contradiction:
ImproveprecisionVSAvoidcost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent substitutes expensive ball bearings with a simpler roller element that is cheaper to manufacture and replace. The roller's design allows for adequate precision at a lower cost, making the tool more economically viable for production applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent extracts the essential function of the ball bearing (providing a rolling contact surface) while removing the complex, expensive components. The simplified roller design retains the necessary precision function at a fraction of the cost.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stress or pressure

If hydraulic pressure is constantly adjusted, then contact stress control is improved, but device complexity is increased

Engineering Contradiction:
Improvecontact stress controlVSAvoiddevice complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The patent employs a spring-loaded mechanism that automatically adjusts and maintains constant contact stress between the roller and workpiece without requiring external hydraulic pressure adjustment. The spring force self-regulates the contact pressure, eliminating the need for complex hydraulic control systems while maintaining precise stress control.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the hydraulic pressure control system with a mechanical spring-loaded system. This substitution simplifies the device by eliminating hydraulic components and their associated control mechanisms, while still achieving the desired contact stress control through elastic spring force.

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

4Strength

If contact stress is increased to improve material properties, then material improvement is improved, but material damage is increased

Engineering Contradiction:
Improvematerial improvementVSAvoidmaterial damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates a load cell that provides real-time feedback on the contact force applied to the workpiece. This feedback mechanism allows the system to monitor and control the contact stress, ensuring it remains within the optimal range to improve material properties without causing damage. The load cell data can be used to adjust the spring pre-load or rolling parameters to maintain safe stress levels.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses the load cell measurements to dynamically adjust processing parameters such as rolling speed, number of passes, or spring pre-load force. By changing these parameters based on real-time force feedback, the system optimizes material improvement while preventing excessive contact stress that would cause damage.

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 enables efficient induction of residual compressive stresses in complex geometries with precise control over contact stress, enhancing material properties and production efficiency while reducing material damage and production costs.

Implementation Method 1

a spring-loaded shaft assembly disposed along a first axis

Methodology Applied
Scientific EffectSpring loading: Spring

Implementation Method 2

A load cell is disposed along the first axis between a proximal end of the shaft and the roller disk, and is adapted to measure a downward force applied along the shaft assembly

Methodology Applied
Scientific EffectForce measurement: Force

Implementation Method 3

deep rolling process, which can induce high compressive stresses up to 1.5 mm depth from the surface of a material through localized plastic deformation

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3338950A1Deep rolling tool and method
Publication Date: 2018.06.27 RTX CORP
  • EP3338950A1 patent drawingFigure 1
  • EP3338950A1 patent drawingFigure 2
  • EP3338950A1 patent drawingFigure 3

AI summary

An embodiment of a tool assembly (31) includes a hub (22) connected to a distal end of a spring-loaded shaft assembly disposed along a first axis (24). An upper hub portion (36A) is adjacent to the distal end of the spring-loaded shaft assembly aligned with the first axis (24), and a lower hub portion (36B) extends along a second axis (34), forming a nonzero angle relative to the first axis (24). A roller disk (20) is joined to the lower portion (36B) of the hub (22), and is rotatable about the second axis (34) parallel to the second portion (36B) of the hub (22). A load cell (60) is disposed along the first axis (24) between a proximal end of the shaft and the roller disk, and is adapted to measure a downward force applied along the shaft assembly.