Elastic Sheet Wire Contact Curvature for Coil Spring Gap Exclusion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional vehicle suspension systems with rubber sheets between coil springs and spring bearings are prone to damage due to the entry of mud and sand, leading to potential coating chipping or breakage of the coil springs.

Innovation Solution

An elastic sheet with a circular arc seating portion, inclined sidewall portions, and collapsing margins is interposed between the coil spring and spring bearing, featuring a wire contact surface with a smaller radius of curvature than the coil spring wire, preventing gaps and ensuring tight contact to exclude mud and sand, and a recessed design to manage compressive loads and prevent excessive pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the coil spring is fitted into a semicircular spring groove formed at the upper surface of the rubber sheet, then the coil spring is supported by the rubber sheet, but a gap is formed between the coil spring and the spring groove when the coil spring recovers from compression, allowing mud and sand to enter

Engineering Contradiction:

Improvecoil spring supportVSAvoidgap formation preventing mud and sand entry

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The wire contact surface is formed with a curved surface having a radius of curvature smaller than the wire radius, creating a tighter fit that eliminates gaps between the coil spring and rubber sheet while maintaining support functionality

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The rubber sheet structure is differentiated into distinct functional regions: a seating portion for support, sidewall portions with wire contact surfaces for gap prevention, and inclined surfaces for mud/sand removal, with each region having optimized local properties

Inventive Principle:

Principle #3Local quality

2Reliability

If mud and sand enter the gap between the coil spring and rubber sheet, then the coil spring can be damaged through repeated compression and extension, but adding protective structures increases device complexity

Engineering Contradiction:

Improvecoil spring protection from damageVSAvoidrubber sheet structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple functions are integrated into a single rubber sheet component: support (seating portion), gap prevention (sidewall portions with wire contact surfaces), and contaminant removal (inclined surfaces), eliminating the need for separate protective structures

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rubber sheet itself is designed as a flexible protective structure that actively prevents contaminant entry through its deformable sidewall portions, using the material's inherent flexibility to achieve protection without rigid additional components

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If the radius of curvature of the wire contact surface is made smaller than the wire radius, then tight contact is achieved preventing gap formation, but manufacturing precision requirements increase

Engineering Contradiction:

Improvetight contact preventing gap formationVSAvoidradius of curvature control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The radius of curvature parameter of the wire contact surface is optimized to be smaller than the wire radius, creating a interference fit that generates radial pressure for tight contact, with the specific parameter relationship designed to balance effectiveness and manufacturability

Inventive Principle:

Principle #35Parameter changes

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 elastic sheet effectively prevents mud and sand from entering the gap between the coil spring and the spring bearing, thereby protecting the coil spring from damage and maintaining the integrity of the suspension system.

Implementation Method 1

an elastic sheet interposed between a coil spring that is provided in a suspension apparatus and that extends in an axial direction of the suspension apparatus and a spring bearing that supports the coil spring

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

an inclined surface that is inclined so as to approach the spring bearing as the inclined surface extends widthwise outward from the wire contact surface, and mud, sand, or the like attached to the elastic sheet slides down widthwise outward along the inclined surface

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS9499021B2Elastic sheet and suspension apparatus

Publication Date: 2016.11.22 ASTEMO LTD

AI summary

An elastic sheet includes: a seating portion by which the coil spring is supported and which has a circular arc shape in a view from the axial direction, one circumferential side of the seating portion being a side of entry of the coil spring; and a pair of sidewall portions extending from respective width-wise opposite ends of the seating portion toward the coil spring side, at least one of the sidewall portions has a wire contact surface that contacts a wire forming the coil spring and an inclined surface inclined so as to approach the spring bearing as the inclined surface extends widthwise outward from the wire contact surface, and a radius of curvature of the wire contact surface at least at a side closest to the inclined surface is smaller than a radius of the wire.