Pantograph Contact Strip Pivot Layout for Even Wear Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current collectors for electrically or hybrid-electrically driven vehicles experience uneven wear of contact strips due to forces acting during operation, particularly when the contact wire is inclined, leading to increased current density and risk of plasma flashes.

Innovation Solution

The current collector design features an asymmetrically positioned axis of rotation for the contact strip, which generates a counter-torque to balance the tilting moment caused by frictional forces, maintaining the contact surface parallel to the wire and distributing wear evenly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the contact strip is pressed against the contact wire with a contact force, then electrical energy transmission is enabled, but uneven wear of the contact strip occurs due to the tilting moment caused by frictional forces

Engineering Contradiction:
Improveelectrical energy transmissionVSAvoidcontact strip wear
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies asymmetry by positioning the rotation axis of the contact strip not at the center of the contact surface, but at an offset position. This asymmetric positioning creates a counter-torque that balances the tilting moment caused by frictional forces during sliding contact, thereby preventing uneven wear while maintaining reliable electrical energy transmission from the overhead line system to the vehicle-mounted traction drive

Inventive Principle:
Principle #4Asymmetry

2Reliability

If the contact strip maintains linear contact with the contact wire, then electrical sliding contact is formed, but increased current density and plasma flashes occur due to point-like contact from uneven wear

Engineering Contradiction:
Improveelectrical sliding contactVSAvoidcurrent density and plasma flashes
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The asymmetric positioning of the rotation axis relative to the contact strip prevents the development of uneven wear patterns. By creating a counter-torque that balances the friction-induced tilting moment, the contact surface maintains its intended linear contact geometry with the contact wire, ensuring uniform current distribution and preventing harmful plasma flashes

Inventive Principle:
Principle #4Asymmetry

3Device complexity

If the rotation axis is positioned centrally below the contact strips, then the support frame structure is simplified, but the contact strip experiences unbalanced tilting moment leading to uneven wear

Engineering Contradiction:
Improvesupport frame structureVSAvoidcontact strip wear
Core Design Contradiction:
Device complexityVSLoss of substance

Solution Approach 1:

The patent deliberately introduces asymmetry in the rotation axis positioning to counterbalance the tilting moment caused by frictional forces. This asymmetric design, while slightly increasing structural complexity, is necessary to prevent uneven wear of the contact strip and maintain consistent electrical contact performance throughout the contact strip's service life

Inventive Principle:
Principle #4Asymmetry

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 design significantly reduces wear on the contact strip by minimizing the total torque, ensuring consistent contact surface alignment with the wire and extending the lifespan of the contact strip.

Implementation Method 1

a frictional force acting counter to the direction of travel of the vehicle, which, due to the at least one rotation axis of the joint arrangement arranged below the contact surface, imparts a tilting moment on the contact strip

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4477450A1Current collector for an electric or hybrid electric vehicle and vehicle equipped with same
Publication Date: 2024.12.18 SIEMENS MOBILITY GMBH
  • EP4477450A1 patent drawingFigure 1~2
  • EP4477450A1 patent drawingFigure 3~4
  • EP4477450A1 patent drawingFigure 5

AI summary

The invention relates to a current collector (1) for a vehicle for supplying traction energy during travel from a contact wire (2) of an overhead line system installed along the route. It comprises at least one contact strip (3) extending parallel to a transverse direction (Y) of the vehicle and an erectable support frame (6) with a base joint for supporting the support frame (6) on the vehicle and with a joint arrangement (7) having at least one axis of rotation (D) extending parallel to the transverse direction (Y) of the vehicle for rotatably mounting the at least one contact strip (3) on the support frame (6). A lifting device serves to erect the support frame (6) and to generate a contact force (FK) with which the at least one contact strip (3) can be pressed against the contact wire (2) to form an electrical sliding contact.According to the invention, the at least one axis of rotation (D) is arranged relative to the at least one contact strip (3) such that a tilting moment (MK) imposed on the at least one contact strip (3) by a frictional force (FR) in the contact contact with the contact wire (2) can be compensated by an opposing counter-moment (MG) imposed on the at least one contact strip (3) by the contact force (FK). This reduces the wear of the pantograph (1).