Bellows Retaining Ring Segmented Shoulder for Disc Brake Pressure Relief

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Solution Overview

Problem

The existing arrangement of bellows on disc brake guide rails creates an airtight system that leads to air accumulation and pressure buildup, causing damage and overheating issues when the brake caliper moves, especially during brake pad changes, due to the inability of air to escape effectively.

Innovation Solution

The contact shoulder of the retaining ring is partially cut out to allow the sealing ring to lift off the groove when pressure builds up, enabling air to escape and preventing overpressure, with the geometry of the recesses determining the limit pressure for pressure reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sealing ring is pressed firmly into the groove to create an airtight system, then the protective function against dirt and moisture is improved, but air accumulation and pressure buildup occur when the brake caliper moves

Engineering Contradiction:
Improveprotective functionVSAvoidinternal pressure
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The contact shoulder is designed with differentiated local properties: most of it provides support to maintain sealing, while specific regions are cut out to allow controlled lifting. This creates zones with different functions - sealing zones and pressure relief zones - resolving the contradiction between maintaining airtightness and preventing pressure buildup.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sealing ring's position is made dynamic rather than fixed. When internal pressure increases, the sealing ring can lift off the groove bottom through the cut-out regions, allowing air to escape. When pressure normalizes, it returns to the sealed position. This dynamic adjustment resolves the contradiction between maintaining sealing and relieving pressure.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the bellows is compressed quickly during brake pad changes, then the brake maintenance efficiency is improved, but damage to the bellows occurs due to immediate pressure buildup

Engineering Contradiction:
Improvebrake maintenance efficiencyVSAvoidbellows durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The cut-out regions are pre-designed into the contact shoulder structure, creating ready-made pressure relief pathways before any compression occurs. When rapid compression happens during brake pad changes, air can immediately escape through these pre-prepared channels, preventing the pressure buildup that would damage the bellows and maintaining both productivity and reliability.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the sealing ring is fully supported on the contact shoulder, then the sealing reliability is improved, but the bellows cannot equalize pressure with the environment

Engineering Contradiction:
Improvesealing reliabilityVSAvoidpressure equalization capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The contact shoulder is designed with differentiated local properties: most of it provides support to maintain sealing, while specific regions are cut out to allow controlled lifting. This creates zones with different functions - sealing zones and pressure relief zones - resolving the contradiction between maintaining airtightness and preventing pressure buildup.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sealing ring's position is made dynamic rather than fixed. When internal pressure increases, the sealing ring can lift off the groove bottom through the cut-out regions, allowing air to escape. When pressure normalizes, it returns to the sealed position. This dynamic adjustment resolves the contradiction between maintaining sealing and relieving pressure.

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

This solution ensures immediate pressure equalization between the bellows' interior and the environment, preventing damage and overheating, while maintaining the bellows' protective function and reducing production and assembly costs.

Implementation Method 1

the sealing ring can be lifted off the bottom of the groove of the guide bar when there is an overpressure in the interior of the bellows

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2276944B1Arrangement of a bellow on a guide mandrel of a disc brake
Publication Date: 2011.11.23 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP2276944B1 patent drawingFigure 1~2
  • EP2276944B1 patent drawingFigure 3

AI summary

The invention relates to an arrangement of a bellows (2) on a guide mandrel (1) of a disc brake, particularly of a commercial vehicle, wherein an end of the bellows (2) comprising a sealing ring (3), particularly a quadring lies in a circumferential groove (4) of the guide mandrel (1), and is thereby pressed into the groove (4) by a retaining ring (5) placed thereon, designed so that an air passage can form in the contact area of the sealing ring (3) at the base of the groove (4), reducing the volume enclosed by the bellows (2) and the guide mandrel (1). To this end, the contact shoulder (6) formed on the retaining ring (5) is circumferentially interrupted in segments.