Rail Brake Cylinder Locking System for Power Loss Reduction

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Solution Overview

Problem

Existing brake systems for rail vehicles face challenges in maintaining a high braking force without external energy, particularly when parked and needing to be towed, as they suffer from power loss due to play in the locking device, limiting the gear wheel diameter and tooth pitch optimization.

Innovation Solution

A brake cylinder with a locking device featuring multiple blocking elements and a non-self-locking thread mechanism, allowing for mechanical engagement and release of the service brake, utilizing a threaded nut with pawls that can be actuated by both the control piston and emergency release plunger, reducing power loss and maintaining locking force without external energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the gear diameter is increased and tooth pitch is decreased to reduce gear slippage and power loss, then power loss is reduced, but the gear diameter is limited by available space and tooth pitch is limited by load-bearing capacity

Engineering Contradiction:
Improvepower lossVSAvoidavailable space
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The locking device is divided into multiple locking elements (at least two) that are distributed around the circumference of the threaded nut. This segmentation allows the system to achieve better locking performance without increasing the overall gear diameter, as each locking element handles a portion of the load rather than requiring a single large-gear design.

Inventive Principle:
Principle #1Segmentation

2Loss of energy

If a single locking element is used, then the device complexity is low, but power loss occurs due to play in the mechanism and gear rotation back before being locked

Engineering Contradiction:
Improvepower lossVSAvoidnumber of locking elements
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The locking device is divided into multiple locking elements (at least two) that are distributed around the circumference of the threaded nut. This segmentation allows the system to achieve better locking performance without increasing the overall gear diameter, as each locking element handles a portion of the load rather than requiring a single large-gear design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses more locking elements than the minimum single element, providing excessive locking action to eliminate play and prevent gear rotation back. This ensures that the braking force is maintained without energy loss, with each locking element providing redundant security and eliminating the backlash problems that would occur with a single locking element.

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If the gear diameter is increased to reduce tooth pitch and minimize slippage, then locking precision is improved, but the available space for the brake cylinder is exceeded

Engineering Contradiction:
Improvelocking precisionVSAvoidbrake cylinder volume
Core Design Contradiction:
Manufacturing precisionVSVolume of stationary object

Solution Approach 1:

The locking device is divided into multiple locking elements (at least two) that are distributed around the circumference of the threaded nut. This segmentation allows the system to achieve better locking performance without increasing the overall gear diameter, as each locking element handles a portion of the load rather than requiring a single large-gear design.

Inventive Principle:
Principle #1Segmentation

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 effectively reduces power loss and maintains the required locking force, ensuring the vehicle remains secured against rolling away, even without a pneumatic pressure supply, while optimizing component design for compactness and efficient operation.

Implementation Method 1

the piston tube is designed with a non-self-locking thread which engages with a threaded nut rotatably mounted in the housing

Methodology Applied
Scientific EffectThread mechanism: Screw

Implementation Method 2

the at least two pawls, by engaging with the teeth of the threaded nut, block its rotation about the piston axis, wherein the at least two pawls are each pressed into engagement with the teeth of the threaded nut by means of a spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3849862B1Brake cylinder with a locking system for mechanically locking the brake force
Publication Date: 2023.04.26 KNORR BREMSE SYST FUR SCHIENENFAHRZEUGE GMBH
  • EP3849862B1 patent drawingFigure 1
  • EP3849862B1 patent drawingFigure 2
  • EP3849862B1 patent drawingFigure 3

AI summary

The invention relates to a brake cylinder (1) comprising a locking device (10) for mechanical brake force locking, in particular for rail vehicles, and comprising a service brake piston (2) which can be axially moved inside a housing (1) and which can be moved by applying a pressure medium thereto and which is coupled to a piston tube (5), said piston tube (5) being provided with a non-self-locking thread (9) which is engaged with a threaded nut (7) which is rotatably mounted in the housing (1), and the locking device (10) cooperating with toothing (8) of the threaded nut (7). The brake cylinder is designed such that the locking device (10) comprises at least two locking elements (11, 12, 20), a control piston (13), and an emergency release tappet (14).