Sealing Element with Spacer for Brake Cylinder Noise Reduction

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Solution Overview

Problem

Rapid release of the brake in motor vehicle braking systems leads to rapid pressure drop in the brake cylinder's pressure chamber, causing flow noises and potential damage due to premature pressure balancing between the pressure chamber and the fluid reservoir, which existing sealing elements fail to adequately manage.

Innovation Solution

A sealing element with a non-sealing spacer element on its back, featuring a sealing ring that projects axially and is radially arranged within the spacer element, allowing for early overflow and reducing flow noises by ensuring pressure balancing occurs before the inner sealing lip loses its seal, and providing redundancy in case of outer sealing lip failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sealing element back is pressed onto the groove wall to create a permanent sealing area, then sealing reliability is improved, but rapid pressure balancing cannot occur causing flow noises and cavitation

Engineering Contradiction:

Improvesealing reliabilityVSAvoidflow noises and cavitation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The sealing element back is segmented into multiple functional regions: a non-sealing spacer element region that allows fluid passage, and a sealing ring region that provides sealing when needed. This segmentation enables the back to perform dual functions - allowing rapid pressure equalization while maintaining sealing capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the sealing element back have different sealing properties. The spacer element region has non-sealing local quality to enable fluid flow, while the sealing ring region has sealing local quality. This local differentiation allows the back to permit rapid pressure balancing in some areas while maintaining sealing in others.

Inventive Principle:

Principle #3Local quality

2Reliability

If the outer sealing lip is used for sealing the groove, then sealing function is achieved, but it may fail requiring redundancy

Engineering Contradiction:

Improvesealing functionVSAvoidsealing element structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The sealing ring on the sealing element back is positioned to make contact with the groove wall before the outer sealing lip in certain operating conditions. This preliminary action provides early sealing support and prevents lip failure, while the lip remains the primary sealing element under normal conditions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sealing ring acts as a backup sealing mechanism that engages beforehand when the outer sealing lip shows signs of failure or under extreme pressure conditions. This beforehand cushioning prevents complete sealing failure and provides a safety margin.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the spacer element prevents sticking during rapid piston reset, then operational reliability is improved, but it may cause premature pressure balancing

Engineering Contradiction:

Improveoperational reliabilityVSAvoidpressure balancing timing

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The spacer element's effect on pressure balancing is dynamic rather than static. During normal operation, it prevents sticking and maintains reliability. During rapid release, the system dynamics allow fluid to flow through the spacer region, enabling timely pressure equalization without causing harmful cavitation.

Inventive Principle:

Principle #15Dynamics

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 or eliminates flow noises and ensures continued sealing functionality by allowing early pressure balancing and maintaining the seal even when the outer sealing lip is compromised, thus preventing abrupt pressure drops and potential damage.

Implementation Method 1

a sealing ring (37) which is arranged radially within the spacer element (39), which projects beyond the sealing ring (37) in the axial direction

Methodology Applied

Scientific EffectSealing contact:

Implementation Method 2

on which at least one non-sealing spacer element (39) is provided... allowing for early overflow

Methodology Applied

Scientific EffectFluid flow through spacer:

Implementation Method 3

an inner sealing lip for contact with the pressure piston

Methodology Applied

Scientific EffectSealing contact:

Implementation Method 4

an outer sealing lip for contact with a floor of the ring-shaped groove

Methodology Applied

Scientific EffectSealing contact:

Implementation Method 5

the back section of the sealing element is pressed onto the side wall of the ring-shaped groove into which the sealing element is inserted

Methodology Applied

Scientific EffectPressure-induced sealing: Pressure Increase

Data Source

PatentUS7966813B2Sealing element for a brake cylinder of a vehicle braking system

Publication Date: 2011.06.28 ZF ACTIVE SAFETY GMBH

AI summary

A sealing element seals a pressure piston which is movably arranged in a housing of a brake cylinder. The sealing element may be inserted into a ring-shaped groove which is provided in the housing. The sealing element includes an outer sealing lip for contact with a floor of the ring-shaped groove, an inner sealing lip for contact with the pressure piston, and a sealing element back. At least one non-sealing spacer element is provided on the sealing element back.