Spring Brake Cylinder External Bleeding Valve

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Solution Overview

Problem

Existing spring-loaded brake cylinders experience annoying whistling noises due to air flows during certain operating conditions, particularly when the service brake pressure is below certain threshold values, leading to air escaping from the spring chamber into the atmosphere.

Innovation Solution

A valve device is integrated into the release spindle between the spring chamber and the environment, which opens or blocks the flow connection based on the pressure in the spring chamber, allowing excess pressure to be reduced externally without noise, independent of the service brake chamber pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If air flows from the spring chamber into the service brake chamber through the vent valve, then the spring chamber is vented, but annoying whistling noises occur

Engineering Contradiction:
Improveventing functionVSAvoidwhistling noises
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention extracts the venting function from the internal path (spring chamber → service brake chamber → atmosphere) and creates a separate external path (spring chamber → release spindle → atmosphere). This separates the venting function from the noise-generating internal flow path, eliminating the whistling noises while maintaining venting capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The release spindle acts as an intermediary component that provides an alternative flow path for air from the spring chamber to the atmosphere. By introducing this intermediate structure, air can escape without passing through the sealing gap of the spring-loaded brake piston that causes the whistling noise.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the vent valve remains closed to prevent noise, then no whistling occurs, but excess pressure in the spring chamber cannot be released

Engineering Contradiction:
Improvewhistling noisesVSAvoidpressure release
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention segments the pressure release function into two independent paths: an internal path through the vent valve for controlled venting during normal operation, and an external path through the release spindle for excess pressure release. This segmentation allows both functions to operate independently without interfering with each other, preventing both noise and pressure buildup.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the pressure threshold parameter for the external venting path by using the spring force on the venting element to define when the external path opens. This creates a pressure-dependent control mechanism where the external path only activates when necessary (excess pressure), while the internal path handles normal venting operations.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If internal venting through the service brake chamber is used, then the structure is compact, but noise occurs during hill starts when service brake pressure is low

Engineering Contradiction:
Improveventing structureVSAvoidwhistling noises
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The release spindle is given multiple functions: it serves as both the release mechanism for the spring brake and as the venting path for the spring chamber. By making the release spindle multi-functional, the invention adds the noise-free venting capability without requiring a completely separate dedicated venting component, thus maintaining relative structural compactness.

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

This solution effectively reduces or eliminates disturbing noises by managing air flow externally, maintaining functionality even when starting on hills or slopes, and integrates a dual function for releasing the spring brake and venting the spring chamber with a reduced number of components.

Implementation Method 1

a valve device is formed in the release spindle which opens or blocks a flow connection between the spring chamber and the environment depending on the pressure prevailing in the spring chamber

Methodology Applied
Scientific EffectPressure-dependent valve operation: Valve

Implementation Method 2

a spring-loaded brake piston which is arranged in the spring-loaded brake cylinder and can be actuated by at least one storage spring

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 3

excess pressure to be reduced into the environment without a flow that causes the disturbing noises

Methodology Applied
Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentEP2376318B1Spring brake cylinder with external bleeding
Publication Date: 2012.09.26 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP2376318B1 patent drawingFigure 1
  • EP2376318B1 patent drawingFigure 2

AI summary

The invention relates to a spring brake cylinder (1) for vehicle brake systems, comprising a spring brake piston (8) that is located in a spring brake cylinder (4) and can be actuated by at least one accumulator spring (10), said piston separating a spring chamber (14) that houses the accumulator spring (10) from a spring brake chamber (12) of the spring brake cylinder (4) that can be aerated and bled, and comprising a release unit (64) for the manual release of the spring brake or a release actuated by a drive unit. The release unit (64) contains a release spindle (72) that co-operates with a spring brake piston rod (18) of the spring brake piston (8), is held in an opening (66) of the spring brake cylinder (4) and can be actuated from outside the spring brake cylinder (4). According to the invention, a flow connection (82) containing a valve unit (74) is provided in the release spindle (72), between the spring chamber (14) and the environment, said valve unit (74) opening and blocking the flow connection (82) depending on the pressure that prevails in the spring chamber (14).