Railway Vehicle Movable Covers for Bogie Drag Reduction

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Solution Overview

Problem

Existing railway vehicles face challenges in reducing aerodynamic drag and energy consumption due to air flowing into cavities around bogies, which are necessary for turning on curved tracks, and require easy maintenance of these covers.

Innovation Solution

A railway vehicle with movable cover devices that include movable covers, accommodation parts, and drive devices to control the covers, which reduce air flow into bogie spaces while allowing easy maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If covers are fixed to bogies to suppress air flow into cavities, then aerodynamic drag is reduced, but bogie maintenance becomes difficult

Engineering Contradiction:
Improveaerodynamic dragVSAvoidbogie maintenance
Core Design Contradiction:
Loss of energyVSEase of repair

Solution Approach 1:

The cover is designed to be movable rather than fixed, allowing it to dynamically change position between a closed state during operation to reduce aerodynamic drag and an open state during maintenance to allow easy access to the bogie. The movable cover is guided by guide rails and can be positioned at multiple locations along the longitudinal direction of the vehicle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cover structure is divided into separate functional components: the movable cover itself, the guide rails that constrain its movement, and the drive device that positions it. This segmentation allows the cover to be independently controlled and moved without affecting the bogie structure, facilitating maintenance while maintaining aerodynamic performance during operation.

Inventive Principle:
Principle #1Segmentation

2Ease of repair

If covers are removed to facilitate bogie maintenance, then maintenance becomes easy, but aerodynamic drag increases

Engineering Contradiction:
Improvebogie maintenanceVSAvoidaerodynamic drag
Core Design Contradiction:
Ease of repairVSLoss of energy

Solution Approach 1:

The cover transitions from a static removed state to a dynamic movable state, allowing it to be positioned as needed. During maintenance, the cover can be moved to an open position that facilitates access to the bogie, while during operation it moves to a closed position that reduces aerodynamic drag, thus resolving the contradiction between maintenance ease and energy efficiency.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If mesh covers are used to cover cavity openings, then air flow into cavities is suppressed, but the structure becomes more complex

Engineering Contradiction:
Improveair flow suppressionVSAvoidcover structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The cover utilizes a thin, flexible plate structure that can be moved along guide rails rather than using complex mesh structures. This thin-film approach effectively suppresses air flow into the cavities while maintaining a simpler overall structure compared to mesh covers, as the cover can be positioned to completely block the cavity openings when closed.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP4169798B1Railway vehicle and control method for movable cover of railway vehicle
Publication Date: 2025.10.01 HITACHI LTD
  • EP4169798B1 patent drawingFigure 1
  • EP4169798B1 patent drawingFigure 2
  • EP4169798B1 patent drawingFigure 3

AI summary

An object is to provide a railway vehicle which can promote energy saving by suppressing air flows into space portions around bogies of a running railway vehicle and can make bogie maintenance easy. An underfloor portion (54) is provided with a space portion (58) to accommodate a bogie (52). The space portion (58) is formed in space partitioned by an end-portion closing plate (6) rising in the height direction from an end part on the bogie side of each underside closing plate (7) which is provided downward of an underframe (55) to be approximately in parallel with the underframe (55) and the underside of the underframe (55). Each movable cover device (10A) includes a movable cover (11a) which covers the underside of the space portion (58) at least partly from a lower end part of an end-portion closing plate (6), an accommodation part (15a) to accommodate the movable cover (11a), and drive devices (13) to drive the movable cover (11a).