Railroad Bogie Sliding Frame and Flexible Bolster Support

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Solution Overview

Problem

Conventional railroad car bogies face challenges in reducing lateral forces and wheel load fluctuations when navigating curved tracks, leading to increased risk of derailment due to excessive rotational resistance and restricted relative longitudinal movement between the bolster and frame bodies.

Innovation Solution

A bogie design featuring a first and second frame body with slidable longitudinal support, axle box suspensions, and a core receiver to support the bolster, allowing self-steering of wheelsets and flexible connection between the bolster and frame bodies to reduce rotational resistance and facilitate smooth relative movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the bolster is supported by a pair of right and left side bearings and center plates to connect the bolster and frame bodies, then the bolster is stably supported, but large rotational resistance is generated making it difficult for wheelsets to return to normal orientation

Engineering Contradiction:
Improvebolster support stabilityVSAvoidwheelset returnability to normal orientation
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The bolster support system is segmented into multiple independent support points (right side bearing, left side bearing, right center plate, left center plate) that can move relative to each other, allowing the bolster to rotate with reduced resistance while maintaining overall stability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support structure transitions from a rigid fixed connection to a dynamic system where the bolster can rotate relative to the frame bodies. The side bearings and center plates are positioned to allow rotational movement while providing stable support, enabling the wheelsets to naturally return to normal orientation after curving

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If the two frame bodies are rigidly connected to reduce structural complexity, then manufacturing is easier, but relative longitudinal movement is restricted preventing self-steering of wheelsets

Engineering Contradiction:
Improveframe body connection simplicityVSAvoidwheelset self-steering capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The connection between the two frame bodies is designed to be dynamically movable in the longitudinal direction while maintaining structural integrity. This allows the frame bodies to slide relative to each other, enabling the wheelsets to self-steer in response to track curvature while keeping the overall structure relatively simple

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connection structure allows change in the relative position parameter (longitudinal distance) between the two frame bodies. By permitting this parameter to vary dynamically, the system achieves self-steering capability without requiring complex active control mechanisms

Inventive Principle:
Principle #35Parameter changes

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 design effectively reduces lateral forces and wheel load fluctuations, ensuring stable wheel alignment and balanced loads across the track, thereby minimizing the risk of derailment, especially in transition curve sections.

Implementation Method 1

axle box suspensions configured to elastically support the respective axle boxes

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3492392B1Railroad car bogie, and railroad car provided with the bogie
Publication Date: 2021.01.20 NIPPON STEEL CORPORATION
  • EP3492392B1 patent drawingFigure 1
  • EP3492392B1 patent drawingFigure 2
  • EP3492392B1 patent drawingFigure 3A~3B

AI summary

A bogie includes: a first frame body (10) which includes a right side beam (11) and a first cross beam (12); a second frame body (20) which includes a left side beam (21) and a second cross beam (22); and a bolster (56). The first and second frame bodies (10, 20) support each other in a slidable manner in a longitudinal direction. A center portion of the bolster (56) is supported by a core receiver (30). The bolster (56) and the first cross beam (12) are supported in a flexible manner by a first connecting portion (52A) disposed on the right side of the core receiver (30), and the bolster (56) and the second cross beam (22) are supported in a flexible manner by a second connecting portion (52B) disposed on the left side of the core receiver (30). With such a configuration, fluctuation in lateral force and wheel load at a curved railroad track can be suppressed.