Plate Spring Boundary Layer Compressive Stress
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Solution Overview
Problem
Plate springs and undulating springs face challenges in meeting service life requirements under static and dynamic loads, especially when subjected to high forces and limited installation spaces, leading to increased costs and space requirements due to the need for multiple arrangements to manage load cycles effectively.
Innovation Solution
A process that introduces internal compressive stress in the boundary layer of plate springs and undulating springs by rollingly compressing surface regions with a ball or roller, or treating them with shot peening while elastically deforming, to enhance load-bearing capacity and service life, with the compressive stress being maximized in deeper regions and the surface smoothed to prevent crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shot peening is used to generate internal compressive stress in the boundary layer, then the service life under dynamic load is improved, but the internal compressive stress is reduced or eliminated by tensile stresses under high load conditions
Solution Approach 1:
The patent applies preliminary action by performing surface compression (shot peening or rolling) before the spring is subjected to service loads. This creates internal compressive stress in advance that counteracts the tensile stresses that will occur during operation. The compressive stress is established in the boundary layer before loading, so it is ready to offset the harmful tensile stresses when the spring is in use, thereby improving service life even under high load conditions.
2Reliability
If multiple plate springs or undulating springs are used to reduce loads on individual springs, then the service life requirement is met, but the installation space and costs increase
Solution Approach 1:
The patent changes the stress state parameter in the boundary layer from tensile to compressive through surface compression treatment. This parameter change allows a single spring to withstand higher loads and more load cycles by preventing crack initiation and propagation. As a result, the system can use fewer springs (instead of multiple arrangements) while still meeting service life requirements, thereby reducing installation space and associated costs.
3Strength
If the spring is pressed flat to increase internal compressive stress, then the load-bearing capacity is improved, but the spring travel is reduced
Solution Approach 1:
The patent applies local quality by compressing only the surface regions (boundary layer) of the spring, not the entire spring structure. The surface compression is localized to create internal compressive stress where it is most needed (at the surface where cracks would initiate), while leaving the overall spring geometry and travel characteristics largely intact. This selective local treatment improves load-bearing capacity without significantly reducing spring travel.
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
Significantly increases the static and dynamic load-bearing capacity of plate springs and undulating springs, extending their service life and reducing the risk of crack formation, while minimizing the number of components needed and installation space required.
Implementation Method 1
surface regions which are subjected to tensile stresses when the spring is under load are provided with an internal compressive stress in the boundary layer by rollingly compressing these surface layers with a ball or a roller
Implementation Method 2
surface regions which are subjected to tensile stresses when the spring is under load are provided with an internal compressive stress in the boundary layer by treating these surface layers with shot peening while the spring is in its elastically deformed state
Implementation Method 3
An internal compressive stress in the boundary layer prevents the formation of stress and crack propagation from the surface, which leads to an increase in the fatigue strength of the component
Data Source
AI summary
A process for producing plate springs or undulating springs wherein surface regions which are subjected to tensile stresses when the spring is under load are provided with an internal compressive stress in the boundary layer, wherein said surface regions are rollingly compressed by a ball or roller or subjected to tensile stress and compressed by shot peening.