Self-Adjusting Air Spring System for Cab Oscillation Damping

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Solution Overview

Problem

Current air spring systems are ineffective in minimizing repeated oscillations during off-road travel, fail to maintain comfort and proper ride height, and do not adequately address cab roll during turns, especially due to limitations in damping and sensing mechanisms.

Innovation Solution

A self-adjusting, self-damping air spring system with a primary and secondary air spring configuration, where the secondary air spring provides opposition forces to the primary air spring, and a valve system that dynamically adjusts pressure between the two air springs to maintain desired spacing and dampen oscillations, using a rigid connection and valve mechanism to manage air flow and pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single air spring is used with a level sensor, then the system is simple in structure, but it cannot effectively dampen oscillations during off-road travel

Engineering Contradiction:
Improveoscillation damping effectivenessVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The single air spring is divided into two separate air springs (first and second air springs). Each air spring can independently respond to oscillations, providing better damping effectiveness while maintaining relative system simplicity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two air springs are connected by a rigid connection that allows them to work together as a unified system. The rigid connection transfers forces between the air springs, enabling them to provide combined oscillation damping while maintaining structural integrity

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If shock absorbers are added to prior art air springs, then oscillation damping is improved, but the system complexity increases and damping is only effective under certain conditions

Engineering Contradiction:
Improveoscillation dampingVSAvoidsystem components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The damping function is merged with the air spring system itself rather than being a separate shock absorber component. The interaction between the two air springs and rigid connection provides inherent damping without requiring additional shock absorber components

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system provides dynamic damping that adapts to different operating conditions. The damping force automatically adjusts based on the oscillation frequency and amplitude, making it effective across a wider range of road conditions compared to fixed damping characteristics

Inventive Principle:
Principle #15Dynamics

3Reliability

If a center-mounted level sensor is used, then the sensing mechanism is simple, but it cannot detect cab roll during turns

Engineering Contradiction:
Improvecab roll detectionVSAvoidsensing mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The single center-mounted sensor is replaced with multiple sensors positioned at different locations (including corner-mounted level sensors). This segmentation allows each sensor to detect local conditions, including cab roll during turns, while providing comprehensive coverage

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensing capability is extended from only vertical height detection to include rotational detection. Corner-mounted sensors can detect changes in cab orientation and roll by measuring height differences at different corners, adding a rotational dimension to the sensing capability

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

The system effectively reduces oscillations and maintains ride height across varying road conditions, providing improved comfort and stability by dynamically adjusting pressure and stiffness in response to changes in vehicle load and movement, thereby reducing the impact of resonance and cab roll.

Implementation Method 1

a second air spring in fluid communication with the first air spring, where the second air spring is capable of providing an opposition force in response to a force acting on the first air spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a valve system that dynamically adjusts pressure between the two air springs to maintain desired spacing and dampen oscillations

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP2935931B1Self-adjusting, self-damping air spring system and method of damping oscillation
Publication Date: 2018.08.22 VOLVO GROUP NORTH AMERICA LLC
  • EP2935931B1 patent drawingFigure 1
  • EP2935931B1 patent drawingFigure 2
  • EP2935931B1 patent drawingFigure 3

AI summary

A self-adjusting, self-damping air spring having a first air spring disposed between a cab and a frame of a vehicle and a second air spring in fluid communication with the first air spring. The second air spring positioned relative to the first to provide an opposition force in response to a change in height of the first air spring. This change in height corresponds to a change in displacement between the cab and the frame. The opposition force provided by the second air spring acting to dampen the changes in displacement.