Coned Disc Spring with Deformable Corner Projections

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Solution Overview

Problem

Coned disc springs fail to effectively inhibit high-frequency vibration transmission due to hysteresis generated by friction between the inner and outer peripheries and counter members, and height adjustment is impractical without altering load characteristics.

Innovation Solution

A spring design featuring a main body with projections at the inner and outer peripheries and elastically deformable corner portions that prevent sliding and friction, allowing for height adjustment without changing the inner and outer diameters, thus eliminating hysteresis in load characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the spring constant of the support portion is set small to lower natural frequency, then vibration transmission is inhibited, but deflection amount increases and the spring becomes large

Engineering Contradiction:
Improvevibration transmission inhibitionVSAvoidspring size
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The spring is divided into a main body portion and multiple projections at the periphery portions. This segmentation allows the main body to provide the necessary deflection for vibration inhibition while the projections prevent sliding, enabling a more compact design without sacrificing vibration isolation performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds projections at the periphery portions of the spring, utilizing the radial dimension to prevent sliding between the spring and counter members. This dimensional addition allows the spring to maintain small size while achieving both vibration inhibition and preventing hysteresis from friction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Force

If coned disc spring deforms to be almost flat by application of load, then load support capability is achieved, but friction generates between inner and outer periphery portions and counter members causing hysteresis

Engineering Contradiction:
Improveload support capabilityVSAvoidhysteresis
Core Design Contradiction:
ForceVSLoss of energy

Solution Approach 1:

The invention extracts the sliding prevention function from the main body of the spring by adding separate projections at the periphery portions. These projections specifically address the friction problem between the spring and counter members during deformation, eliminating hysteresis while maintaining load support capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The projections are strategically placed only at the periphery portions of the spring where contact with counter members occurs. This local modification prevents sliding and friction at the critical contact points without affecting the overall deformation characteristics and load support capability of the spring.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If upper and lower surfaces are ground for height adjustment, then height can be adjusted, but load characteristics greatly change and inner and outer diameters change causing bump

Engineering Contradiction:
Improveheight adjustmentVSAvoidload characteristics stability
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The projections are designed with predetermined dimensions and positions during manufacturing, establishing fixed reference points for the spring's inner and outer diameters. This preliminary dimensional establishment allows subsequent height adjustment through projection modification without affecting the critical diameter dimensions, preventing bump when installing the spring.

Inventive Principle:
Principle #10Preliminary action

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 spring effectively prevents hysteresis and allows for height adjustment without increasing the number of parts or altering the spring's dimensions, ensuring efficient vibration inhibition across varying frequencies.

Implementation Method 1

the corner portion is elastically deformable such that an angle of the corner portion changes depending on the pressing force

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the projection has an abutting portion which projects from the periphery portion of the main body portion to one member of the first member and the second member and abuts thereon

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2287490B1spring
Publication Date: 2018.07.11 NHK SPRING CO LTD
  • EP2287490B1 patent drawingFigure 1A~1B
  • EP2287490B1 patent drawingFigure 2A~2B
  • EP2287490B1 patent drawingFigure 3~5

AI summary

The first corner portion 13, which is formed at the boundary portion between the main body portion 10 and the first cylindrical portion 11 which are positioned to each other as shown in Figs. 2A and 2B, can elastically deform in application of load such that the angle α of the first corner portion 13 changes depending on the pressing force from the first member 101. In this case, the first corner portion 13 can move toward the outside of the inner periphery portion of the main body portion 10 (the left side in the Figure) while the angle α changes. The second corner portion 14, which is formed at the boundary portion between the main body portion 10 and the second cylindrical portion 12 which are positioned to each other as shown in Figs. 2A and 2B, has the same function as that of the first corner portion 13, and it can move toward the outside of the outer periphery portion of the main body portion 10 (the right side in the Figure) while the angle β changes depending on the pressing force from the second member 102 in the elastic deformation of the second corner portion 14. As a result, the spring can prevent generation of hysteresis in load characteristics without increasing the number of parts, and enables height adjustment of the spring.