Air Spring Plunger Ventilation for Vacuum Prevention

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Solution Overview

Problem

In commercial vehicles, air springs face issues when the vehicle is raised, leading to a drop in pressure within the air bellows, potential vacuum formation, and uneven rolling of the air sleeve upon landing, which can cause damage.

Innovation Solution

An air spring with a plunger that includes ventilation openings and a non-return valve, ensuring the air bellows' pressure remains above ambient pressure by connecting the bellows' interior with the plunger's interior, preventing collapse and ensuring smooth operation without external pressurization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the vehicle is raised for loading, then the axle is lifted off the ground, but the air bellows is stretched and pressure drops causing vacuum formation

Engineering Contradiction:
Improvevehicle loading capabilityVSAvoidair bellows pressure stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The ventilation opening is pre-positioned in the plunger casing body at a location that becomes exposed when the air spring is extended. This preliminary positioning ensures that as soon as the air bellows stretches during vehicle lifting, the ventilation opening automatically exposes and allows air intake, preventing vacuum formation before it can cause damage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The plunger casing body acts as an intermediary element that houses the ventilation opening. When the air spring extends, the plunger moves relative to the air bellows, causing the ventilation opening to expose and mediate the connection between the air bellows interior and the external environment, allowing pressure equalization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the air bellows is vented to prevent vacuum, then negative pressure is prevented, but the air bellows may collapse without proper support

Engineering Contradiction:
Improveair bellows pressure controlVSAvoidair bellows structural integrity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The air spring system is self-regulating through the strategically positioned ventilation opening. When the air bellows collapses or extends excessively, the opening automatically exposes to allow air intake, and when the air spring returns to its normal position, the opening becomes covered again. This self-service mechanism maintains pressure without requiring external control systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The ventilation opening is positioned at a specific location on the plunger casing body where it only exposes under extreme extension conditions. This local positioning ensures that ventilation occurs only where and when needed, preventing vacuum formation during normal operation while maintaining structural integrity during collapse.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the vehicle is lowered after loading, then the axle touches the ground, but uneven rolling of the air sleeve can damage the air bellows

Engineering Contradiction:
Improvevehicle grounding capabilityVSAvoidair bellows damage from uneven rolling
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The ventilation opening is pre-positioned to expose before the air spring fully extends during the lowering process. This preliminary exposure ensures that air can enter the bellows in advance, maintaining positive pressure that supports the bellows structure and prevents collapse or uneven rolling when the vehicle touches the ground.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The ventilation opening provides preliminary anti-action by allowing air intake before the harmful collapse or uneven rolling can occur. This preemptive pressure equalization counteracts the tendency of the air bellows to collapse under its own weight when the vehicle is lowered, preventing damage before it happens.

Inventive Principle:
Principle #9Preliminary anti-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 solution provides reliable ventilation and prevents damage to the air bellows by maintaining pressure, ensuring even rolling and operational reliability when the vehicle is raised and lowered.

Implementation Method 1

a non-return valve, through which the interior of the bellows can be connected, in particular fluidically connected or brought into fluid communication, with the interior of the plunger

Methodology Applied
Scientific EffectNon-return valve mechanism: Valve

Implementation Method 2

ensuring the air bellows' pressure remains above ambient pressure by connecting the bellows' interior with the plunger's interior

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

the plunger has at least one ventilation opening, which is arranged in the jacket body of the plunger and via which the interior of the plunger can be fluidically connected or brought into fluid communication with the environment

Methodology Applied
Scientific EffectFluid communication:

Implementation Method 4

the air bellows is fastened to an upper connection area of ​​the plunger and can roll over a lateral surface of the plunger during a compression movement

Methodology Applied
Scientific EffectRolling motion:

Data Source

PatentEP2846061B1Air spring and plunger for air spring
Publication Date: 2017.09.13 SAF HOLLAND GMBH
  • EP2846061B1 patent drawingFigure 1
  • EP2846061B1 patent drawingFigure 2a~2g
  • EP2846061B1 patent drawingFigure 3~4

AI summary

An air spring for a vehicle, in particular for a commercial vehicle, comprising an air bellows (20) with a bellows interior (23) that can be filled with compressed air, and a plunger (40) which is coupled to the air bellows (20) and has a jacket body (46) that forms a rolling surface for the air bellows (20). The plunger (40) is designed as a hollow body and has a piston interior (43). A valve (70) is provided for venting the bellows interior (23), through which the bellows interior (23) can be fluidically connected to the piston interior (43). The plunger (40) has at least one vent opening (80) which is arranged in the jacket body (46) of the plunger (40) and through which the piston interior (43) can be fluidically connected to the environment.