Non-axisymmetric Deep Rolling Tool for Complex Geometries
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Solution Overview
Problem
Existing deep rolling tools are expensive, complex, and inefficient for processing complex geometries and thin walls, with difficulties in controlling contact stress and maintaining production throughput, especially when used with conventional machine tools.
Innovation Solution
A robotic assembly with a non-axisymmetric deep rolling tool featuring a spring-loaded shaft assembly, a hub with angled axes, and a rotatable roller disk with a variable profile, coupled with a load cell for real-time force monitoring and closed-loop feedback control, allowing precise application of compressive stresses on nonplanar surfaces.
Engineering Contradictions & Design Principles
Engineering 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
Solution Approach 1:
The patent replaces expensive, precision ball bearings with a simpler, more economical roller element that can be easily replaced. The roller is designed as a straightforward cylindrical or conical element rather than a precision ball bearing, reducing cost while maintaining adequate function for the application.
Solution Approach 2:
The patent uses a roller element with a curved surface (cylindrical or conical geometry) instead of a spherical ball bearing. This curvature provides the necessary contact geometry for inducing compressive stresses while allowing for larger contact area and faster processing compared to ball bearings.
2Manufacturing precision
If a ball bearing is used in known LPB tools, then precision is improved, but cost is increased
Solution Approach 1:
The patent replaces expensive, precision ball bearings with a simpler, more economical roller element that can be easily replaced. The roller is designed as a straightforward cylindrical or conical element rather than a precision ball bearing, reducing cost while maintaining adequate function for the application.
3Stress or pressure
If hydraulic pressure is constantly adjusted to maintain contact stress, then contact stress control is improved, but device complexity is increased
Solution Approach 1:
The patent employs a spring-loaded mechanism that automatically maintains contact stress between the roller and workpiece. The spring force self-adjusts to compensate for variations in workpiece geometry and roller position, eliminating the need for complex hydraulic pressure control systems while maintaining adequate contact stress.
4Manufacturing precision
If a small surface area ball bearing is used, then precision is improved, but productivity is decreased
Solution Approach 1:
The patent uses a roller element with a curved surface (cylindrical or conical geometry) instead of a spherical ball bearing. This curvature provides the necessary contact geometry for inducing compressive stresses while allowing for larger contact area and faster processing compared to ball bearings.
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
Enables efficient induction of residual compressive stresses on complex geometries with improved production efficiency and precision, reducing fatigue and corrosion damage, while being adaptable to various machine tools and robotic systems.
Implementation Method 1
a spring-loaded shaft assembly disposed along a first axis
Implementation Method 2
localized plastic deformation to prevent corrosion pits, foreign object damage, crack initiation
Data Source
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AI summary
An embodiment of a tool assembly (31) includes a robotic assembly (100), a tool mount, and a non-axisymmetric deep rolling tool. The robotic assembly (100) includes a plurality of linear arms (102) connected in series between a base end (104) and a working end (106). Adjacent ones of the plurality of arms (102) are connected via a corresponding plurality of multi-axis joints (110) such that the working end (106) is articulated by movement of one or more of the plurality of arms (102) relative to one or more of the plurality of multi-axis joints (110). The tool mount is connected to one of the linear arms (102) or one of the multi-axis joints (110) at the working end of the robotic assembly (100). The non-axisymmetric deep rolling tool is connected to the tool mount, and includes a spring-loaded shaft assembly disposed along a first axis (24). A hub (22) has an upper hub portion (36A) adjacent to the distal end of the spring-loaded shaft assembly aligned with the first axis (24), and a lower hub portion (36B) extending 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).