Rail Vehicle Bogie Stepladder Unsprung Mounting

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Solution Overview

Problem

Existing rail vehicle designs face challenges with reduced installation space and increased risk of structural gauge violations due to stepladders protruding into the running gear, leading to potential collisions and clearance profile exceedances.

Innovation Solution

Arranging the stepladder on the non-sprung level of the chassis, with options for external or internal bearings, and using elastic bearings for mechanical decoupling, allows for more space and reduced risk of collisions by keeping the stepladder aligned with the car body steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the stepladder is mounted on the car body, then access to the driver's cab is provided, but the available space for the stepladder is reduced and the risk of exceeding the clearance gauge increases

Engineering Contradiction:

Improveaccess to driver's cabVSAvoidavailable space for stepladder

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

Instead of mounting the stepladder on the car body (sprung plane), the patent inverts the approach by mounting it on the bogie frame (unsprung plane). This reversal of the mounting location provides more available space for the stepladder in the transverse direction while reducing lateral displacements and rotational movements that could cause clearance gauge violations.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of operation

If the stepladder is mounted on the car body, then access to the driver's cab is provided, but the risk of exceeding the prescribed clearance gauge increases due to lateral displacements and rotational movements

Engineering Contradiction:

Improveaccess to driver's cabVSAvoidclearance gauge compliance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent reverses the mounting approach from car body to bogie frame, which significantly reduces lateral displacements and rotational movements during operation. This inversion maintains clearance gauge compliance while still providing reliable access to the driver's cab.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs a dynamically adjustable stepladder that can extend and retract. During normal operation, the stepladder retracts to minimize clearance issues. When access is needed, it extends to provide the required stepping function. This dynamic behavior ensures both clearance gauge compliance and ease of access.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If the stepladder is mounted on the chassis frame, then access is provided, but installation space is reduced and the risk of exceeding the loading gauge increases

Engineering Contradiction:

Improveaccess to vehicleVSAvoidinstallation space for steps

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

Instead of mounting the stepladder on the chassis frame (sprung plane), the patent inverts the approach by mounting it on the bogie frame (unsprung plane). This provides significantly more installation space for the stepladder in the transverse direction while maintaining all access functions.

Inventive Principle:

Principle #13The other way round (Inversion)

4Area of stationary object

If a fixed stepladder is provided on the bogie, then installation space is increased, but the clear width may conflict with car body steps on straight tracks

Engineering Contradiction:

Improveinstallation space for stepladderVSAvoidcontinuous access on straight track

Core Design Contradiction:

Area of stationary objectVSEase of operation

Solution Approach 1:

The patent employs a dynamically adjustable stepladder that can extend and retract. During normal operation on straight tracks, the stepladder retracts to align with car body steps, ensuring continuous access. When needed, it extends to provide the required stepping function, thus maintaining both installation space benefits and ergonomic access.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The stepladder is designed to quickly extend and retract as needed, allowing it to skip between retracted and extended positions. This rapid transition capability ensures that the stepladder does not permanently obstruct the clear width on straight tracks while still providing access when required.

Inventive Principle:

Principle #21Skipping (Rushing through)

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 provides increased installation space, reduces the risk of structural gauge violations, and ensures ergonomic access by maintaining the stepladder's alignment with car body steps, eliminating the need for extendable or fold-out steps.

Implementation Method 1

At least a first elastic bearing and a second elastic bearing are arranged between the stepladder and the wheelset bearing 4, which result in a mechanical decoupling of the wheelset bearing 4 from the stepladder 3

Methodology Applied

Scientific EffectElastic bearing: Elasticity

Data Source

PatentEP3344510B1Bogie for a rail vehicle

Publication Date: 2019.12.25 SIEMENS MOBILITY AUSTRIA GMBH

Figure 1~2

AI summary

The invention relates to a bogie for a railway vehicle, comprising a primary suspension (6) with an unsprung plane, which has a wheel (7), a wheel set shaft (10) and a wheel set bearing (4) as well as at least one stepladder (3) for entry into a driver's cabin. In order to create advantageous design conditions, it is proposed that the stepladder (3) is arranged on the unsprung plane of the bogie.