Railway Switch Drive Torque Limiting Replaces Mechanical Coupling

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Solution Overview

Problem

Conventional switch drive systems for railway switches are structurally complex, costly, and require frequent maintenance due to mechanical wear, necessitating multiple variants and extensive assembly adjustments.

Innovation Solution

A switch drive device with a motor controller that adjusts and limits the torque of a drive motor electrically, eliminating the need for mechanical actuating force couplings, and incorporating a brushless DC motor and ball screw drive for simplified design and maintenance-free operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical actuating force coupling is used to limit control force, then switch blade damage is prevented, but device complexity and weight increase

Engineering Contradiction:
Improveswitch blade protectionVSAvoidmechanical actuating force coupling
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical actuating force coupling with an electrical control system. The motor controller electrically limits the maximum torque of the drive motor, thereby controlling the actuating force without requiring mechanical coupling components. This substitution eliminates the mechanical complexity while maintaining the protective function against switch blade damage.

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

Solution Approach 2:

The patent changes the control parameter from mechanical force coupling to electrical torque limitation. By parameterizing the motor controller to electrically limit the maximum torque, the system achieves actuating force control through electrical parameters rather than mechanical components, reducing device complexity while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple variants of point drive systems are manufactured for different applications, then adaptability is improved, but manufacturing costs and spare parts inventory increase

Engineering Contradiction:
Improveapplication-specific configurationVSAvoidnumber of variants
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent creates a universal point drive system platform where the motor controller can be parameterized through software for different applications. Instead of manufacturing multiple hardware variants, a single hardware design serves multiple purposes by allowing flexible electrical parameter configuration, thereby reducing manufacturing complexity and spare parts inventory while maintaining adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent enables different applications to be accommodated by changing electrical parameters in the motor controller rather than manufacturing different hardware variants. Through software parameterization of torque limits, speeds, and control characteristics, a single physical system adapts to various railway switch applications, significantly reducing the number of variants needed.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If mechanical actuating force coupling components are used, then actuating force limitation is achieved, but assembly adjustment time and commissioning costs increase

Engineering Contradiction:
Improveactuating force controlVSAvoidassembly adjustment and commissioning
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces mechanical actuating force coupling with electrical torque control. The motor controller is pre-configured with parameterized torque limits that automatically enforce actuating force control without requiring mechanical adjustment during assembly. This eliminates time-consuming mechanical adjustments and reduces commissioning costs.

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

Solution Approach 2:

The patent performs the actuating force control configuration in advance through motor controller parameterization during manufacturing, rather than requiring adjustment during field assembly. The electrical parameters are pre-set to provide appropriate torque limits for different applications, eliminating the need for time-consuming on-site mechanical adjustments.

Inventive Principle:
Principle #10Preliminary action

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 structural complexity, lowers production and maintenance costs, enhances reliability, and allows for quick commissioning and parameterization, enabling a single variant to serve various applications with improved diagnostic and operational efficiency.

Implementation Method 1

at least one drive motor connected to the adjusting slide, which is designed to move the adjusting slide

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

incorporating a brushless DC motor and ball screw drive for simplified design and maintenance-free operation

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP4617141A1Switch drive device and method for switching a railway switch
Publication Date: 2025.09.17 SIEMENS MOBILITY GMBH
  • EP4617141A1 patent drawingFigure 1
  • EP4617141A1 patent drawingFigure 2
  • EP4617141A1 patent drawingFigure 3

AI summary

The invention relates to a switch drive device (2) for switching a railway switch (1), comprising at least one adjusting slide (5) for connection to at least one movable part of the railway switch (1), such as a switch tongue (4), and comprising at least one drive motor (7) connected to the adjusting slide (5) and designed to move the adjusting slide (5). In order to optimize the switch drive device (2), the invention provides that the switch drive device (2) comprises at least one motor controller (8) connected to the drive motor (7) and controlling the drive motor (7), by means of which a maximum torque of the drive motor (7) and thus a maximum actuating force of the adjusting slide (5) can be adjusted. The invention also relates to a method for switching a railway switch.