Rail Brake Actuator Position Locking for Power-Loss Braking

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Solution Overview

Problem

Current rail vehicle braking systems, particularly pneumatically regulated brakes, suffer from slow and imprecise regulation, risk of malfunctions due to leakages, and inability to ensure consistent braking force, especially when the electric power supply is interrupted.

Innovation Solution

A brake system incorporating a brake actuator, gear assembly, self-locking mechanism, stepper motor, and position sensor that allows precise positioning and locking of brake components, ensuring consistent braking force even without power supply, using a backup power unit for continued operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pneumatically regulated brakes are used, then braking force can be applied, but regulation is slow and imprecise

Engineering Contradiction:
Improvebraking force regulation precisionVSAvoidbraking force regulation speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces the pneumatic regulation system with an electrically controlled system. The brake actuator receives electric control signals and converts them to mechanical braking force through a drive mechanism, eliminating the slow and imprecise pneumatic regulation in favor of fast and accurate electric control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If the same brake units are used for service braking and emergency braking, then device complexity is reduced, but reliability decreases due to inability to verify braking position

Engineering Contradiction:
Improvebrake system structureVSAvoidbraking force verification
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a position sensor that detects the position of the pressing member and provides feedback signals to the control unit. This feedback mechanism allows the system to verify whether the braking force has been correctly applied, significantly improving reliability while maintaining reasonable device complexity.

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If electric power supply is interrupted, then energy consumption is reduced, but braking force cannot be maintained

Engineering Contradiction:
Improveelectric power consumptionVSAvoidbraking force maintenance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements a self-locking mechanism that automatically engages when electric power is interrupted or reduced. This mechanism uses a spring-loaded locking structure with a release element that normally holds the pressing member in the engaged position. When power fails, the spring force automatically overcomes the holding force and maintains the braking action, providing beforehand cushioning against power failure.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If a self-locking mechanism is added to maintain braking force without power, then reliability improves, but device complexity increases

Engineering Contradiction:
Improvebraking force maintenance without powerVSAvoidbrake system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the self-locking mechanism with the existing brake actuator structure. The release element is integrated into the drive mechanism, and the locking function is combined with the pressing member assembly. This integration approach maintains reliability improvement while minimizing the increase in device complexity by sharing components and structural elements.

Inventive Principle:
Principle #5Merging (Combining)

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 system provides highly accurate and reliable braking, with immediate malfunction detection and secure locking of brake components, ensuring safety and efficiency in various braking conditions.

Implementation Method 1

The self-locking mechanism is configured to automatically lock the first and second pressing members if a supply of electric power to the brake unit fails

Methodology Applied
Scientific EffectSelf-locking mechanism: Ratchet

Implementation Method 2

The position sensor is configured to produce a position signal indicating an angular position of a power transmission shaft of the stepper motor

Methodology Applied
Scientific EffectPosition sensing:

Implementation Method 3

the stepper motor is configured to act on the gear assembly so as to cause the first and second pressing members to move towards or away from the rotatable member and attain a specified position interrelationship

Methodology Applied
Scientific EffectStepper motor conversion: Linear Motor

Implementation Method 4

The gear assembly is arranged to operate mechanically on the first and second pressing members

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 5

the brake unit is configured to receive the electric brake-force signal, and in response thereto cause the first and second pressing members to apply a braking force to the rotatable member

Methodology Applied
Scientific EffectFriction braking: Friction

Data Source

PatentEP4223612B1Brake system for a rail vehicle
Publication Date: 2024.07.24 DELLNER BRAKES AB
  • EP4223612B1 patent drawingFigure 1~2
  • EP4223612B1 patent drawingFigure 3~8
  • EP4223612B1 patent drawingFigure 4a~4b

AI summary

A rail vehicle (100) has a brake system containing a brake actuator (120) and a brake unit (200). The brake actuator (120) receives a brake command (cmdp) and produces a resulting electric brake-force signal (BF). The brake unit (200) contains first and second pressing members (211) and a rotatable member (110) being mechanically linked to at least one wheel (105) of the rail vehicle (100). When receiving the electric brake-force signal (BF), the brake unit (200) causes the first and second pressing members (211) to apply a braking force to the rotatable member (110). A gear assembly (220) in the brake unit (200) operates mechanically on the first and second pressing members (211). A stepper motor (230), in turn, acts on the gear assembly (120) in response to the electric brake-force signal (BF), thus causing the first and second pressing members (211) to move towards or away from the rotatable member (110) and attain a specified position interrelationship. Based on a position signal (P) indicating an angular position of the stepper motor's (230) power transmission shaft, the brake unit (200) determines if the specified position interrelationship has been attained; and if so, it stops producing the electric brake-force signal (BF) to allow a self-locking mechanism to lock the first and second pressing members (211).