Switchable Clutch Rail Vehicle Drive Train Dynamics

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Solution Overview

Problem

Drive arrangements for rail vehicles with master-slave configurations face issues due to differing rail wheel diameters causing twisting moments, increased wear, and reduced driving comfort due to vibrations, necessitating heavier and more massive components.

Innovation Solution

Incorporating a switchable clutch controlled by an electronic control unit to selectively engage or disengage the power flow between the first and second wheel sets, allowing for operation with either one or both axles based on speed and load conditions, thereby reducing tension and vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a master-slave drive arrangement is used to drive both wheel set shafts, then drive power is distributed to both axles, but twisting moments arise due to different rail wheel diameters causing increased wear and vibrations

Engineering Contradiction:
Improvedrive power distributionVSAvoidtwisting moments and vibrations
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The clutch connection between the master and slave wheel set shafts is made switchable rather than permanent. The electronic control unit activates the clutch only when high drive power is required (e.g., during startup), allowing the system to dynamically transition between two-axle and one-axle drive modes. This resolves the contradiction by enabling power distribution to both axles only when necessary, while minimizing twisting moments and vibrations during normal operation.

Inventive Principle:
Principle #15Dynamics

2Power

If the switchable clutch is engaged to drive both wheel sets, then drive power is transmitted to both axles, but the components must be designed more massive to withstand the tensions

Engineering Contradiction:
Improvedrive power transmissionVSAvoidcomponent mass
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The clutch connection between the master and slave wheel set shafts is made switchable rather than permanent. The electronic control unit activates the clutch only when high drive power is required (e.g., during startup), allowing the system to dynamically transition between two-axle and one-axle drive modes. This resolves the contradiction by enabling power distribution to both axles only when necessary, while minimizing twisting moments and vibrations during normal operation.

Inventive Principle:
Principle #15Dynamics

3Power

If continuous two-axle drive is used, then high drive power is always available, but wear increases and service life decreases due to constant tensions in the drive train

Engineering Contradiction:
Improvedrive power availabilityVSAvoidservice life
Core Design Contradiction:
PowerVSDuration of action of stationary object

Solution Approach 1:

The clutch connection between the master and slave wheel set shafts is made switchable rather than permanent. The electronic control unit activates the clutch only when high drive power is required (e.g., during startup), allowing the system to dynamically transition between two-axle and one-axle drive modes. This resolves the contradiction by enabling power distribution to both axles only when necessary, while minimizing twisting moments and vibrations during normal operation.

Inventive Principle:
Principle #15Dynamics

4Duration of action of stationary object

If a switchable clutch is added to separate the power flow, then wear is reduced and service life is extended, but device complexity increases

Engineering Contradiction:
Improveservice lifeVSAvoidclutch control system
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The electronic control unit is given multiple functions: it controls the switchable clutch, monitors wheel slip conditions, and manages overall drive power distribution. By making the control unit multi-functional rather than adding a separate dedicated control system, the increase in device complexity is minimized while still achieving the benefit of reduced wear and extended service life through selective clutch engagement.

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

Data Source

PatentEP3461708B1Drive arrangement for a rail vehicle and drive train
Publication Date: 2020.01.08 ZF FRIEDRICHSHAFEN AG
  • EP3461708B1 patent drawingFigure 1
  • EP3461708B1 patent drawingFigure 2

AI summary

A drive arrangement for a rail vehicle is proposed, comprising a first axle gearbox (21) associated with a first axle shaft (22) and a second axle gearbox (23) associated with a second axle shaft (24). A drive torque is transmitted through the first axle gearbox (21) to drive both the first and second axle shafts (22, 24). A switchable clutch (25), controllable by an electronic control unit (27), is arranged in the power transmission path between the first axle gearbox (21) and the second axle gearbox (23). A corresponding drive train is also proposed.