Switch Drive Coupling Element Surface Roughness

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Solution Overview

Problem

The existing switch drive mechanisms experience variations in forces required for opening due to changes in vertical force and coefficient of friction over time, leading to potential corrosion and wear, which affects the reliability and maintenance intervals of the point drive.

Innovation Solution

The coupling element and adjusting slide have a machined surface with a roughness greater than or equal to 2 μm, avoiding polishing to maintain lubricant adhesion and prevent corrosion, with optional dry lubricant coating to ensure consistent tribological properties and extended maintenance intervals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the contact surface is polished to reduce friction, then friction is reduced, but lubricant adhesion is compromised leading to corrosion

Engineering Contradiction:
Improvefriction forceVSAvoidcorrosion resistance
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The contact surface is intentionally left with a specific roughness range (Ra 1.6-6.3 μm) rather than being polished smooth. This local surface quality characteristic provides both adequate friction reduction and sufficient lubricant retention capacity, resolving the contradiction between low friction and corrosion resistance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The surface roughness parameter is specifically controlled within the range of Ra 1.6-6.3 μm. This parameter change from fully polished (low Ra) to moderately rough (higher Ra) surface creates the optimal balance for both friction characteristics and lubricant adhesion, preventing corrosion while maintaining operational efficiency.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of stationary object

If the contact surface is made smooth to reduce wear, then wear is reduced, but lubricant cannot be retained leading to increased corrosion

Engineering Contradiction:
Improveservice lifeVSAvoidcorrosion
Core Design Contradiction:
Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The contact surface is intentionally left with a specific roughness range (Ra 1.6-6.3 μm) rather than being polished smooth. This local surface quality characteristic provides both adequate friction reduction and sufficient lubricant retention capacity, resolving the contradiction between low friction and corrosion resistance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The surface roughness parameter is specifically controlled within the range of Ra 1.6-6.3 μm. This parameter change from fully polished (low Ra) to moderately rough (higher Ra) surface creates the optimal balance for both friction characteristics and lubricant adhesion, preventing corrosion while maintaining operational efficiency.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the surface is polished to achieve high surface quality, then friction is reduced, but the depressions needed for lubricant absorption are eliminated

Engineering Contradiction:
Improvesurface qualityVSAvoidlubricant retention
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The contact surface is intentionally left with a specific roughness range (Ra 1.6-6.3 μm) rather than being polished smooth. This local surface quality characteristic provides both adequate friction reduction and sufficient lubricant retention capacity, resolving the contradiction between low friction and corrosion resistance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The surface roughness parameter is specifically controlled within the range of Ra 1.6-6.3 μm. This parameter change from fully polished (low Ra) to moderately rough (higher Ra) surface creates the optimal balance for both friction characteristics and lubricant adhesion, preventing corrosion while maintaining operational efficiency.

Inventive Principle:
Principle #35Parameter changes

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 consistent forces for opening the switch over time, prevents corrosion, and extends maintenance intervals by maintaining optimal lubrication and wear resistance, reducing operating costs and improving the reliability of the point drive.

Implementation Method 1

the coupling element and/or the adjusting slide has a surface in the region of a common contact surface which has the features of a machining process without polishing, i.e. is produced by machining without polishing

Methodology Applied
Scientific EffectLubricant adhesion: Adhesive

Implementation Method 2

The friction coefficient on the adjusting slide depends on many parameters, including the lubricant condition, the surface quality of the friction contact

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4360988A1Switch drive and coupling element for the same
Publication Date: 2024.05.01 SIEMENS MOBILITY GMBH
  • EP4360988A1 patent drawingFigure 1
  • EP4360988A1 patent drawingFigure 2
  • EP4360988A1 patent drawingFigure 3

AI summary

The invention relates to a switch drive (1) comprising an actuating module (SM) for setting a switch and a drive module (AM) for driving the actuating module (SM). The actuating module (SM) has an actuating slide (14) and a locking clutch (11) for transmitting an actuating force generated by the drive module (AM) to the actuating slide (14). A coupling element (KE) of the locking clutch (11) is in mechanical engagement with the actuating slide (14). The coupling element (KE) and/or the actuating slide (14) has a surface in the area of ​​a common contact surface that exhibits the characteristics of machining without polishing. The invention further comprises an actuating slide (14), a coupling element (KE), a method for manufacturing an actuating slide (14), a computer program, and a staging device.