Bogie Friction Damper Structure to Prevent Wedge Jamming

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Solution Overview

Problem

Existing bogie suspension systems face issues with improper wedge function due to inadequate material selection, part shaping, and insufficient spring rigidity, leading to jamming and incorrect bogie placement, resulting in increased rolling resistance and damage.

Innovation Solution

A friction damper with a guide cylinder terminated by a C-shaped closing cap and a slidable friction element, featuring a disc spring or elastomer, allowing radial positioning of wheelsets and smooth regulation of spring tension, which reduces maintenance costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If friction wedges are applied between fifth wheel columns and base surfaces with triangular cross-section, then movement damping is achieved through friction resistance, but improper material selection and shaping may cause wedge jamming and incorrect bogie placement

Engineering Contradiction:
Improvedamping function reliabilityVSAvoidwedge movement smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the geometric parameters of the friction wedge from a traditional triangular cross-section to a trapezoidal cross-section with specific angle ranges (30-45 degrees for the inclined surface, 15-30 degrees for the counter-inclined surface). This parameter optimization ensures smooth wedge movement within the guide cylinder while maintaining effective friction damping, preventing jamming issues that occur with improper shaping.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a guide cylinder as an intermediary component that houses the friction wedge and provides guided movement. The guide cylinder with its specific internal geometry (including a C-shaped closing cap with flange) acts as a mediator between the wedge and surrounding structures, ensuring controlled motion and preventing lateral instability of supporting springs that could cause wedge jamming.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If springs with greater lateral rigidity are used to stabilize suspension, then bogie placement accuracy improves, but device complexity increases due to additional division plates and interconnections

Engineering Contradiction:
Improvebogie placement accuracyVSAvoidspring kit structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the spring support system by introducing division plates that split neighboring springs into separate groups. These division plates are interconnected to form a rigid structure that provides the necessary lateral stability for accurate bogie placement. The segmentation allows each spring group to function independently while collectively providing enhanced rigidity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple division plates into an interconnected rigid structure that acts as a unified stabilizing element. By merging the division plates and interconnecting them, the system achieves greater lateral rigidity without requiring completely separate support structures for each spring, thus managing complexity while improving placement accuracy.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If friction wedges with rollers and low-friction inserts are used, then wedge movement smoothness improves, but manufacturing complexity and maintenance requirements increase

Engineering Contradiction:
Improvewedge movement smoothnessVSAvoidwedge structure simplicity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent employs a simpler friction wedge design without complex roller mechanisms or multiple low-friction inserts. The wedge uses a straightforward trapezoidal geometry with friction surfaces that are easier to manufacture. While this approach may require more frequent replacement compared to highly sophisticated designs, it significantly reduces manufacturing complexity and initial cost, aligning with the principle of using simpler, more economical solutions.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The solution enhances bogie suspension by ensuring smooth movement and reducing maintenance costs through improved friction damping and stability, particularly in curved tracks.

Implementation Method 1

a disc spring or elastomer, allowing radial positioning of wheelsets and smooth regulation of spring tension

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a slidable friction element in the shape of a cylinder with a flange the diameter of which corresponds to the inner diameter of the guide cylinder

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4065447B1Friction damper, particularly in bogie suspension system
Publication Date: 2024.08.21 GREENBRIER POLAND SP ZOO
  • EP4065447B1 patent drawingFigure 1
  • EP4065447B1 patent drawingFigure 2

AI summary

The guide cylinder (9) is closed on one side by a cap (10) in the shape of a horizontal C that includes outer wall of the guide cylinder (9), with an inner flange on the opposite side, whereas the spring element (11) placed inside the guide cylinder (9) is adjacent to the slidable friction element (12) in the shape of a cylinder fitted with a flange the diameter of which corresponds to the inner diameter of the guide cylinder (9). The flange is located inside the guide cylinder (9), while the remaining part of the friction element (12) protrudes outside the guide cylinder (9). When the spring element (11) is most stretched, the flange of the friction element (12) rests on the flange (12) of the guide cylinder (9).