Pneumatic Spring Preload Adjuster for Low-Wear Shock Threads

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Solution Overview

Problem

Existing spring damper devices for motorcycles face challenges with high actuation forces and wear on threads due to the need for strong preload adjustments, which also increases the risk of contamination and component damage.

Innovation Solution

A pneumatically actuated adjusting device that eliminates the need for a separate piston by using a housing with a pressure wall to apply compressive force to the spring device, allowing the adjusting nut to be easily rotated without spring force, and incorporates sealing devices to prevent contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the adjusting nut is moved axially to change spring preload, then the spring behavior can be influenced, but high actuating forces are required and high stress occurs on the threads

Engineering Contradiction:
Improvespring behavior adjustmentVSAvoidactuating force
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The patent replaces the direct mechanical thread engagement system with a pneumatic actuation system. A pneumatic cylinder generates axial force on the adjusting nut through gas pressure, substituting the manual mechanical turning operation. This eliminates the need for high actuating forces on the threads while maintaining spring preload adjustment capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a pneumatic actuation mechanism where compressed gas acts on a piston connected to the adjusting nut. The pneumatic pressure provides the necessary axial force to move the adjusting nut along the tubular body's external thread, enabling spring preload adjustment without direct manual intervention and reducing thread stress.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Adaptability or versatility

If high pressure forces are applied to adjust the spring, then the spring preload can be changed, but wear on the threads increases and contamination risk rises

Engineering Contradiction:
Improvespring preload adjustmentVSAvoidthread durability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the high-stress mechanical thread engagement system with a pneumatic actuation system. The pneumatic cylinder provides the necessary adjustment force through gas pressure acting on a piston, eliminating direct high-force mechanical contact between the adjusting nut and tubular body threads, thereby reducing wear and contamination risk.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a pneumatic piston as an intermediary between the gas pressure source and the adjusting nut. This intermediary transfers the adjustment force without requiring direct high-force thread engagement, reducing wear on the threads and minimizing contamination risk in the threaded connection area.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a separate piston with sealing devices is used to apply pressure, then the spring can be pre-tensioned, but the number of components increases and manufacturing costs rise

Engineering Contradiction:
Improvespring pre-tensioning capabilityVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the piston function with the adjusting nut into a single integrated component. The adjusting nut itself serves as the pressure-receiving element with an internal cavity that accepts the pneumatic actuator, eliminating the need for a separate piston component and its associated sealing devices, thereby reducing component count and manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The adjusting nut is designed to serve multiple functions: it provides the threaded connection for axial adjustment, houses the pneumatic actuator cavity, and transmits the pneumatic force to compress the spring. This multi-functionality eliminates the need for separate piston and sealing components, reducing device complexity while maintaining pre-tensioning capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution reduces manufacturing costs, minimizes wear, and ensures reliable operation by eliminating the need for a separate piston and sealing devices, while maintaining secure force transmission and preventing contamination, thus enhancing the durability and usability of the spring damper device.

Implementation Method 1

the pressure chamber (8) can be acted upon by gas pressure

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Implementation Method 2

a spring device (5) which can be acted upon by a pressure force in an axial direction

Methodology Applied
Scientific EffectElastic potential energy: Spring

Data Source

PatentEP3766711B1Pneumatically actuated adjusting device for loading a spring device of a spring shock absorber device having a tubular body
Publication Date: 2024.08.21 KTM AG
  • EP3766711B1 patent drawingFigure 1
  • EP3766711B1 patent drawingFigure 2
  • EP3766711B1 patent drawingFigure 3

AI summary

A pneumatically actuated adjusting device (1) is provided for actuating a spring assembly (5) of a spring damper assembly (3) having a tubular body (2), with a tubular housing (4) which is designed to enclose the tubular body (2) and has a passage (6) through a circumferential wall of the housing (4), and the adjusting device (1) has an adjusting nut (9) with an internal thread (10) which can be screwed into an external thread (11) of a tubular body (2, 37) of the spring damper assembly (3), wherein the housing (4) is designed to be detachably attached to the adjusting nut (9) and has an internal recess (7) for forming a pressure chamber (8) which is in fluid communication with the passage (6) and the internal recess (7) forms a pressure wall (24),whose fluid action causes a force acting on the housing (4) in the axial longitudinal direction and the housing (4) has a bearing surface (54) designed for spring force application by the spring device.