Rail Vehicle Drive Train Overload Clutch Torque Protection

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Solution Overview

Problem

Existing drive train systems in rail vehicles face issues with limited accuracy and reliability of sensor systems, leading to potential derailments due to blockages and reaction torques, which can cause damage and safety risks, and previous solutions like gear couplings introduce reaction torques into the transmission even after shearing, continuing to disrupt the drive train.

Innovation Solution

A powertrain with an overload clutch integrated into the large wheel of the driving wheel set, which couples the wheel set shaft torque-proofly and releases when a specified switching torque is exceeded, decoupling the drive train to prevent further damage and allow the unaffected wheels to continue operating, thus preventing blockages from affecting the entire drive train.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensor systems are used to detect blockages and overheating, then early detection of failures is improved, but reliability and accuracy deteriorate due to limited sensor accuracy and error rates leading to false messages

Engineering Contradiction:
Improvedetection accuracyVSAvoidsystem reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The overload clutch acts as a mechanical intermediary between the drive unit and the driven components. It provides a purely mechanical solution that does not depend on sensor accuracy or electronic control systems. The clutch mechanically senses overload conditions through torque transmission and automatically disengages when the switching torque is exceeded, eliminating reliance on potentially faulty sensor systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If gear coupling with predetermined breaking point is used to protect against large reaction torques, then protection against torque overload is improved, but harmful reaction torques continue to affect the transmission after shearing occurs

Engineering Contradiction:
Improvetorque protectionVSAvoidreaction torque impact
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The drive train is segmented into independent sections by the overload clutch. When the clutch disengages, it creates a mechanical separation between the drive unit and the driven components (wheel set shaft, large wheel, pinion). This segmentation prevents reaction torques from propagating through the entire system, isolating the overload condition to only the affected section while protecting other components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The overload clutch serves as a mechanical intermediary that interrupts torque transmission. Unlike a gear coupling that merely breaks teeth while maintaining connection, the overload clutch completely disengages the torque path when overloaded, acting as a mechanical fuse that opens the circuit and prevents harmful reaction torques from affecting the transmission and other drive train components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If drive is switched off immediately upon sensor detection, then safety is improved, but productivity deteriorates due to forced interruptions and reduced vehicle availability

Engineering Contradiction:
ImprovesafetyVSAvoidvehicle availability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The overload clutch provides dynamic protection that adapts to actual operating conditions. It remains engaged during normal operation, allowing full power transmission and maintaining productivity. Only when the switching torque is exceeded does it disengage, providing safety precisely when needed. This dynamic response avoids unnecessary shutdowns caused by false sensor messages while ensuring safety during actual overloads.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The overload clutch is a passive, self-acting device that automatically responds to overload conditions without requiring sensor input or electronic control. It protects the drive train through pure mechanical action, eliminating the need for complex sensor systems and control algorithms that can generate false alarms and lead to unnecessary shutdowns.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2805863B1Drive train of a rail vehicle and method for detecting an overload in a drive train
Publication Date: 2019.11.13 BOMBARDIER TRANSPORTATION GMBH
  • EP2805863B1 patent drawingFigure 1
  • EP2805863B1 patent drawingFigure 2
  • EP2805863B1 patent drawingFigure 3

AI summary

A drive train for a rail vehicle is proposed, comprising a wheelset axle (8) and a large gear (2, 3, 4) for transmitting torque from a drive unit (5, 6, 7) to the wheelset axle (1). An overload clutch (3) with a predetermined switching torque (3) is rotationally fixed to the wheelset axle (8) and couples the large gear (2, 3, 4) rotationally fixed to the wheelset axle (1). When the switching torque is exceeded, the overload clutch (3) releases the large gear from the wheelset axle (8).