Disc Spring Residual Stress Shaping at the Inner Circumference
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Solution Overview
Problem
Existing disc spring manufacturing methods apply compressive residual stress maximally at the depth position between the inner and outer circumferential surfaces, rather than on the inner circumferential surface where the highest tensile stress occurs, potentially limiting durability.
Innovation Solution
A method involving the relative rotation of a support body and spring body in sliding contact with a compressive axial force applied, focusing on applying compressive residual stress to the outer end portion of the inner circumferential surface, maximizing it there and decreasing towards the outer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a compressive residual stress is applied by rotating and moving a ball pressed against the inner circumferential surface, then the compressive residual stress is applied to the spring body, but the compressive residual stress is maximized at a depth position between the inner and outer circumferential surfaces rather than on the inner circumferential surface where the highest tensile stress occurs
Solution Approach 1:
The patent replaces the traditional ball-based mechanical system with a chain-based mechanical system. The chain wraps around the inner circumferential surface of the spring body, providing distributed contact along the circumferential direction. This substitution allows the compressive force to be applied more effectively across the inner circumferential surface, maximizing the compressive residual stress at the critical location where tensile stress occurs during operation.
Solution Approach 2:
The patent changes the geometric parameters of the spring body, specifically making the ratio of the inner radius to the outer radius 0.4 or less. This parameter change alters the stress distribution characteristics within the spring body, enabling the compressive residual stress applied through the chain mechanism to be maximized at the inner circumferential surface rather than at intermediate depth positions.
2Reliability
If the compressive residual stress is maximized at a depth position rather than on the inner circumferential surface, then the stress distribution is achieved, but the durability of the disc spring is difficult to improve
Solution Approach 1:
The patent applies compressive residual stress preliminarily to the inner circumferential surface before the spring body is put into service. By using the chain mechanism to wrap around and compress the inner circumferential surface during manufacturing, the patent creates a preliminary compressive stress state that counteracts the tensile stresses that will occur during operation. This preliminary anti-action directly improves durability by preventing stress concentration and fatigue at the critical inner circumferential surface.
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 ensures a disc spring with enhanced durability by maximizing compressive residual stress on the inner circumferential surface where the highest tensile stress occurs, reducing surface roughness and hardness variations, thereby improving resistance to stress concentration and abrasion.
Implementation Method 1
the support body and the spring body are brought into sliding contact with each other
Implementation Method 2
the spring body may be elastically deformed in the axial direction
Data Source
AI summary
A disc spring manufacturing method is a method for manufacturing a disc spring including a spring body formed into an annular shape and having an outer circumferential surface, an inner circumferential surface, an outer circumferential edge, and an inner circumferential edge, and includes applying a compressive residual stress to at least an outer end portion in the radial direction on the inner circumferential surface by relatively rotating a support body supporting at least the outer end portion in the radial direction on the inner circumferential surface and the spring body around a center axis line of the spring body while the support body and the spring body are brought into sliding contact with each other in a state in which a compressive force in an axial direction along the center axis line is applied to the spring body using the support body.