Disc Spring Inside Diameter Precision via Shot Peening Sequence
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Solution Overview
Problem
The production of disc springs faces challenges in achieving high precision and maintaining residual stress on the inside diameter portion, particularly at the tensile surface edge, due to roughness and deformation caused by shot peening after machining, which complicates controlling the inside diameter tolerance and affects durability and sliding performance.
Innovation Solution
A disc spring design with a chamfered portion at the inside diameter portion side edge of the tensile surface, where residual stress from shot peening is applied, followed by machining the inside diameter after shot peening, ensuring the chamfered portion remains and enhances durability and precision by minimizing surface roughness and allowing precise control of the inside diameter tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If shot peening is carried out after machining the inside diameter portion, then residual stress is applied to the disc spring, but roughness is formed on the inside diameter portion and the inside diameter portion is substantially deformed, making it difficult to control inside diameter tolerance
Solution Approach 1:
The patent applies preliminary action by performing shot peening on the entire blank before machining the inside diameter portion. This sequence ensures that residual stress is established in the material before the precision machining operation, preventing subsequent deformation of the inside diameter portion while maintaining the required tolerance. The chamfered portion is formed after shot peening to preserve the residual stress at critical locations.
2Manufacturing precision
If machining of the inside diameter portion is carried out after shot peening, then inside diameter precision can be improved, but the inside diameter portion side edge of the tensile surface in which residual stress is applied is easily removed, and residual stress does not remain
Solution Approach 1:
The patent applies local quality by creating a chamfered portion at the inside diameter portion side edge of the tensile surface after shot peening. This localized geometric feature preserves residual stress at the critical edge location where maximum stress occurs during elastic deformation. The chamfered portion is specifically positioned to maintain residual stress while allowing precision machining of the inside diameter surface, thus resolving the contradiction between precision and stress retention.
3Ease of operation
If the inside diameter portion has a bending surface to prevent inside diameter change during sliding, then sliding performance is improved, but the inside diameter portion side edge of the tensile surface loses residual stress due to machining
Solution Approach 1:
The patent applies local quality by forming a chamfered portion at the specific location of the inside diameter portion side edge of the tensile surface. This localized feature ensures that residual stress is preserved at the critical edge location where maximum stress occurs during elastic deformation, while the bending surface is maintained for optimal sliding performance. The chamfered portion acts as a stress-preserving zone that does not interfere with the overall sliding function.
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
This approach improves the precision of the inside diameter portion, maintains residual stress for enhanced durability, and ensures high-precision clearance with guide shafts, allowing smooth sliding and effective stress distribution during elastic deformation.
Implementation Method 1
residual stress generated by shot peening is applied to at least the tensile surface
Data Source
Figure 1~2D
Figure 3
AI summary
A disc spring and a production method therefor are provided in which an attempt is made to improve precision of an inside diameter portion, and in which residual stress can be applied to an inside diameter portion side edge of a tensile surface. Shot peening is carried out at at least a tensile surface 114A, after a chamfered portion 121A is formed at an inside diameter portion 112A side edge of a tensile surface 114A in a blank 100A. Residual stress is applied to the chamfered portion 121A of the inside diameter portion 112A side edge of the tensile surface 114A. The inside diameter portion 112A is machined after the shot peening. In this case, since at least an outside diameter portion side of the chamfered portion 121A remains, the remaining chamfered portion 121A constitutes the inside diameter portion 112A side edge of the tensile surface 114A after the machining. Therefore, the inside diameter portion 112 side edge of the tensile surface 114 in which the maximum stress can be generated in the disc spring 100 has residual stress.