Compressed Air Control Valve Radial Sealing Ring Design

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Solution Overview

Problem

Control valves in compressed air systems of vehicles have an unfavorably large axial overall height due to their sliding guidance via a central guide sleeve or journal, and the sealing of pressure chambers by a single outer circumference sealing ring is weak, leading to increased dimensions and potential leakage.

Innovation Solution

A radial sealing ring with an axial width matching the control piston's thickness, featuring radially inclined sealing lips and distributed guide bodies around the circumference to reduce axial height and enhance sealing, eliminating the need for a central guide sleeve or shortening its length, and incorporating a fastening groove and venting spaces for improved sealing and air discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a central guide sleeve or journal is used for sliding guidance of the control piston, then the control piston can be guided axially, but the axial overall height of the control valve becomes unfavorably large

Engineering Contradiction:
Improveaxial guidance of control pistonVSAvoidaxial overall height of control valve
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The sealing ring is segmented into multiple functional elements: two sealing lips for sealing purposes and multiple guide bodies distributed around the circumference for guidance. This segmentation allows the sealing and guidance functions to be distributed, eliminating the need for a single large central guide sleeve and thereby reducing the axial height of the control valve.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of providing guidance through a central element extending axially (one-dimensional approach), the guide bodies are distributed around the circumference in a radial arrangement (two-dimensional approach). This dimensional change allows guidance to be achieved without increasing the axial height, as the guide bodies engage with the cylinder wall radially rather than axially.

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

2Device complexity

If only one sealing ring arranged on the outer circumference of the control piston is used, then the structure is simple, but the sealing of the pressure chambers is relatively weak

Engineering Contradiction:
Improvesealing structureVSAvoidsealing of pressure chambers
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The sealing ring is segmented into two radially inclined sealing lips that contact the inner wall of the cylinder at different axial positions. This segmentation creates multiple sealing lines, significantly improving the sealing reliability of the pressure chambers while maintaining a relatively simple overall structure compared to using multiple separate sealing rings.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing lips are designed with radial inclination to match the contact surface on the cylinder wall, creating optimal local sealing contact. This local geometric adaptation enhances the sealing effect at the critical sealing interface without requiring complex sealing structures throughout the entire assembly.

Inventive Principle:
Principle #3Local quality

3Reliability

If guide bodies are added to the sealing ring for radial guidance, then axial height is reduced and sealing is improved, but the sealing ring structure becomes more complex

Engineering Contradiction:
ImprovesealingVSAvoidsealing ring structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The guide bodies and sealing ring are merged into a single integrated component. The guide bodies are formed as integral parts of the sealing ring, combining the sealing function and the guidance function in one element. This merging reduces the total number of parts and assembly steps, offsetting the increased complexity of the sealing ring structure itself while achieving the desired reduction in axial height and improvement in sealing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sealing ring is designed to perform multiple functions simultaneously: sealing the pressure chambers through the sealing lips and providing radial guidance through the guide bodies. This multi-functionality eliminates the need for separate guidance components, reducing the overall device complexity despite the enhanced sealing ring structure.

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 results in a more compact control valve with improved sealing of pressure chambers, preventing piston tilt and leakage, and allowing for efficient axial guidance and air venting, thus enhancing the overall performance and reliability of the control valve.

Implementation Method 1

the control piston, sealed by at least one sealing ring arranged on the outer circumference of the control piston

Methodology Applied
Scientific EffectSealing:

Implementation Method 2

between the two sealing lips on the sealing ring a plurality of guide bodies arranged distributed around the circumference are formed

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3556620B1Control valve for a compressed air system
Publication Date: 2020.09.16 ZF CV SYST EURO BV
  • EP3556620B1 patent drawingFigure 1
  • EP3556620B1 patent drawingFigure 2
  • EP3556620B1 patent drawingFigure 3

AI summary

The invention relates to a control valve (3) of a compressed air system of a vehicle, with at least one control piston (22) which is axially movable in a housing-fixed cylinder (25), wherein two pressure chambers (32, 34) are separated from each other by means of the control piston (22), sealed by means of at least one sealing ring (37) arranged on the outer circumference of the control piston (22).To improve the radial guidance of the control piston (22) and the sealing of the pressure chambers (32, 34) separated by the control piston (22), it is provided that the sealing ring (37) is designed as a radial sealing ring with an axial width largely corresponding to the axial thickness of the control piston (22), that the sealing ring (37) has a radially obliquely outwardly directed sealing lip (39, 40) at each of its two axial edges, bearing against the inner wall (38) of the cylinder (25), and that several circumferentially distributed guide bodies (50) are formed between the two sealing lips (39, 40) on the sealing ring (37).