Eccentric Spring Adjuster for Front Fork Damping Control

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Solution Overview

Problem

Conventional front forks lack adjusters for independently adjusting damping forces during extension and compression while maintaining vehicle height adjustment functionality.

Innovation Solution

The front fork is designed with a spring adjuster mounted eccentrically on the cap, featuring screw portions that protrude into the fork main body and a plate that changes the support positions of the suspension spring, allowing for independent adjustment of damping forces through first and second adjusters without obstructing the cap's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple adjusters are mounted on the cap for adjusting damping forces during extension and compression, then the adaptability of the front fork is improved, but the device complexity increases due to the additional components and their arrangement

Engineering Contradiction:
Improvedamping force adjustment capabilityVSAvoidadjuster arrangement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spring adjuster is positioned eccentrically relative to the cap's central axis, creating an asymmetric arrangement. This asymmetric positioning allows the plate to rotate and change the suspension spring support position while providing clearance for multiple adjusters to be mounted on the cap without interfering with each other's operation

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The adjustment functions are segmented into separate adjusters: a spring adjuster for vehicle height adjustment and separate first/second adjusters for extension and compression damping forces. Each adjuster is independently mounted on the cap, allowing independent adjustment of each parameter without affecting the others

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the spring adjuster is positioned eccentrically to allow plate rotation for vehicle height adjustment, then the ease of operation is improved, but the device complexity increases due to the non-standard mounting position

Engineering Contradiction:
Improvevehicle height adjustmentVSAvoidmounting position complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The spring adjuster is deliberately positioned eccentrically (off-center) on the cap rather than at the central axis. This asymmetric positioning creates the necessary clearance for the plate to rotate freely when the spring adjuster is operated, enabling vehicle height adjustment without interfering with other components

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The spring adjuster operates in a different spatial dimension (radial/rotational movement of the plate) compared to the axial movement of other adjusters. This dimensional separation allows the plate to rotate and change the suspension spring support position in the circumferential direction without conflicting with the axial adjustment operations of other adjusters

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

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 configuration enables precise adjustment of damping forces during both extension and compression, maintaining vehicle height adjustment capabilities without interfering with the adjusters, thus enhancing the fork's damping characteristics and operational flexibility.

Implementation Method 1

a screw portion (35) disposed in an outer periphery of the spring adjuster body (31) and protruded into the fork main body (1)

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

a suspension spring (S) housed in the fork main body (1), configured to bias the fork main body (1) in a direction of extension

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

a damper cartridge (D) housed in the fork main body (1) so as to change damping forces generated by the damper cartridge (D)

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP3287661B1Front fork
Publication Date: 2020.04.29 KYB MOTORCYCLE SUSPENSION CO LTD
  • EP3287661B1 patent drawingFigure 1
  • EP3287661B1 patent drawingFigure 2
  • EP3287661B1 patent drawingFigure 3

AI summary

Provided is a front fork provided with a plurality of adjusters, while including a spring adjuster. In order to achieve the above object, in a front fork F according to the means for solving the problem of the present invention, a spring adjuster A is rotatably mounted on a position eccentric to a center O of a cap 4 as viewed in an axial direction and includes a screw portion 35 disposed in an outer periphery protruded into a fork main body 1, and a plate P in which the screw portion 35 of the spring adjuster A is screwed to change support positions of a suspension spring S is brought into contact with a case (tubular member) 14a at two points on both sides in a circumferential direction of the normal of the case 14a that passes a mounting center of the spring adjuster A. Accordingly, while being prevented from rotating, the plate P can be downsized and can be disposed so as not to interfere with first and second adjusters 5, 6.