Piston Valve U-Ring Sealing for Pneumatic Brake Systems

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Solution Overview

Problem

Piston valves in pneumatic brake systems have limited functionality and high production costs due to the need for external components and precise manufacturing, which increases the load on sealing elements and reduces their lifespan.

Innovation Solution

Incorporating an insert within the housing that fixes the switching piston and positions the sealing element between the insert and housing, allowing the piston valve to function as a check valve and reducing the need for external non-return valves, while using statically acting seals to compensate for manufacturing deviations and hiding connections behind the insert for larger flow cross-sections with smaller dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the sealing element is arranged directly between the housing and the switching piston, then the structure is simple, but the U-ring is subjected to excessive load during switching, reducing its service life

Engineering Contradiction:
Improvestructure simplicityVSAvoidsealing element service life
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The housing is segmented into two parts: the outer housing and an inner insert. The sealing element is positioned between these two segments, allowing it to remain stationary relative to the housing while the switching piston moves against the insert. This segmentation resolves the contradiction by maintaining structural simplicity while reducing the load on the sealing element during switching operations.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the piston valve has basic switching functionality only, then the device complexity is low, but additional functions require external components, increasing overall system costs

Engineering Contradiction:
Improvedevice simplicityVSAvoidproduction costs
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The piston valve is merged with a check valve function by positioning the sealing element to perform both switching and non-return valve functions. This combination eliminates the need for separate external check valves, reducing overall system component count and production costs while maintaining device simplicity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sealing element is designed with multi-functionality, serving as both a switching seal and a check valve component. This universal design allows a single component to fulfill multiple functions, reducing the need for additional external components and lowering overall production costs.

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

3Volume of moving object

If the housing contains all connections and flow paths, then the structural dimensions are large, but the flow cross sections are limited for the given size

Engineering Contradiction:
Improvepiston valve dimensionsVSAvoidflow cross section
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The insert is nested within the housing, creating a compact layered structure. Connections are routed through the insert and housing walls, allowing large flow cross sections to be achieved within small structural dimensions. This nesting arrangement resolves the contradiction by maximizing space utilization.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 design enhances the service life of the sealing element by reducing excessive load and lowers production costs by eliminating the need for external check valves and allowing for more precise manufacturing of the insert and switching piston, while maintaining efficient compressed air path management.

Implementation Method 1

a sealing element (24) that forms a connection seals between the at least two connections (20, 22) in at least one second switching position of the switching piston (18), the sealing element being designed as a U-ring with a flexible sealing lip (26) that works as a non-return valve

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2393698B1Piston valve, especially for a pneumatic brake system in a vehicle
Publication Date: 2015.07.08 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP2393698B1 patent drawingFigure 1
  • EP2393698B1 patent drawingFigure 2
  • EP2393698B1 patent drawingFigure 3

AI summary

A piston valve (10), especially for a pneumatic brake system in a vehicle, is disclosed. Said piston valve (10) comprises a switching piston (18) which can be moved in an axial direction (16) within a zone (12) of a housing (14), at least two connections (20, 22) which are coupled to each other in a first switched position of the switching piston (18), and a sealing element (24) which seals a junction (38) between the at least two connections (20, 22) in at least one second switched position of the switching piston (18). According to the invention, the sealing element (24) is designed as a U-ring that has a flexible sealing lip (26) which acts as a check valve between the at least two connections (20, 22).