Rotational Buffer Devices as Traction Links in Rail Running Gears

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Solution Overview

Problem

Modern low-floor rail vehicles face space constraints within the running gear, making it difficult to accommodate traction linkage elements effectively, leading to inefficient traction force transmission and increased stress on components.

Innovation Solution

Integrating rotational buffer devices with the ability to form a traction link between the running gear and the wagon body, allowing them to transmit a significant fraction of the total traction force, thereby reducing the need for additional traction linkage elements and optimizing space usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate traction linkage elements are used to transmit traction forces, then reliable traction force transmission is achieved, but the space requirements within the running gear increase significantly

Engineering Contradiction:
Improvetraction force transmissionVSAvoidspace within running gear
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the function of traction force transmission into the rotational buffer devices that are already present for damping rotational motions. By equipping these buffer devices with contact surfaces that can transmit longitudinal forces, the invention eliminates the need for separate traction linkage elements, thereby saving space within the running gear while maintaining reliable traction force transmission.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotational buffer devices are designed to perform multiple functions: damping rotational motions between the running gear and wagon body, and transmitting traction forces along the longitudinal direction. This multi-functionality reduces the overall component count and space requirements within the running gear assembly.

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

2Volume of moving object

If traction linkage elements are placed at less favorable locations due to space constraints, then space utilization is improved, but the stress on components increases due to longer force transmission paths

Engineering Contradiction:
Improvespace utilization in running gearVSAvoidstress on running gear components
Core Design Contradiction:
Volume of moving objectVSStress or pressure

Solution Approach 1:

By combining the traction force transmission function with the existing rotational buffer devices located at favorable positions, the invention avoids the need to place separate traction elements at less favorable locations. This maintains optimal stress distribution while utilizing the space-efficient multi-functional design.

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If the rotational buffer devices have a narrow gap for rotational deflection, then space efficiency is improved, but the traction force transmission onset is delayed

Engineering Contradiction:
Improvespace efficiency in running gearVSAvoiddelay in traction force transmission
Core Design Contradiction:
Volume of moving objectVSLoss of time

Solution Approach 1:

The invention combines the rotational buffer function with traction force transmission capability in a single integrated component. The contact surfaces are positioned and dimensioned such that the narrow gap required for rotational deflection does not significantly delay traction force transmission, as the same buffer structure that allows rotation also provides the traction link.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotational buffer devices are designed with dynamic characteristics that allow them to transition smoothly between rotational deflection and traction force transmission. The contact surfaces and damping elements are configured to engage effectively in both functions without significant delay or loss of performance.

Inventive Principle:
Principle #15Dynamics

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 configuration enhances space efficiency, maintains riding comfort by avoiding noticeable delays in traction force transmission, and reduces stress on components by distributing forces effectively within the running gear.

Implementation Method 1

The first rotational buffer device and the second rotational buffer device are adapted to damp a rotational motion between the running gear and the wagon body unit about a rotational axis parallel to the height direction

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2669136B1Rail vehicle unit
Publication Date: 2020.01.01 BOMBARDIER TRANSPORTATION GMBH
  • EP2669136B1 patent drawingFigure 1~2
  • EP2669136B1 patent drawingFigure 3~4
  • EP2669136B1 patent drawingFigure 5~6

AI summary

The present invention relates to a rail vehicle unit, comprising a running gear (102) and a wagon body unit (101.1) forming two contact partners and defining a longitudinal direction, a transverse direction and a height direction. The wagon body unit (101.1) is supported on the running gear (102) via a suspension device (106), a first rotational buffer device (115) and a second rotational buffer device (115) being associated to the running gear (102) and the wagon body unit (101.1). The first rotational buffer device (115) and the second rotational buffer device (115) are adapted to damp a rotational motion between the running gear (102) and the wagon body unit (101.1) about a rotational axis parallel to the height direction. The first rotational buffer device (115) and the second rotational buffer device (115) are configured to form a traction link between the running gear (102) and the wagon body unit (101.1), the traction link being configured to transmit at least a major fraction of a total traction force to be transmitted along the longitudinal direction between the running gear (102) and the wagon body unit (101.1).