Longitudinal Motor Bogie for Low-Floor Rail Vehicles
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Solution Overview
Problem
Existing railway vehicle bogie designs for low-floor vehicles face challenges in reducing bulk, unsprung masses, and complexity, which hinder the achievement of a wide corridor and high-speed travel while maintaining a small footprint.
Innovation Solution
A motorized bogie with an internal chassis, featuring a suspended motor and semi-suspended reduction gear, where the motor is fixed to the chassis and the reduction gear is oscillating on the axle, connected by a mechanical coupling, minimizing unsprung masses and bulk, and allowing for a low-floor configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the motor is placed in the central space of the chassis to reduce transverse bulk, then the bogie width is reduced, but the space available for seating at the bogie is limited
Solution Approach 1:
The motor is positioned in the longitudinal direction within the central space rather than occupying transverse space, allowing the bogie width to remain sufficient for seating while achieving compact transverse dimensions. The motor shaft is oriented longitudinally to drive the axle through the wheelset center, utilizing the longitudinal dimension to resolve the space conflict.
2Weight of moving object
If the hollow shaft drive is used to reduce unsprung mass, then unsprung mass is decreased, but the bogie's overall size in the direction of travel increases
Solution Approach 1:
The motor is extracted from the traditional transverse mounting position and relocated to the longitudinal central space, eliminating the need for hollow shafts and intermediate gears. The motor shaft directly drives the axle through the wheelset center, removing unnecessary transmission components and reducing bogie length while maintaining low unsprung mass.
3Ease of manufacture
If the semi-suspended motor drive system is used to simplify implementation, then ease of manufacture is improved, but unsprung mass increases which limits vehicle speed
Solution Approach 1:
The motor is mounted longitudinally in the central space with its shaft oriented along the longitudinal axis, directly driving the axle through the wheelset center. This dimensional reconfiguration eliminates the need for oscillating motors and complex suspension integrations, achieving both manufacturing simplicity and low unsprung mass by removing unnecessary intermediate components.
Data Source
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AI summary
Motor bogie (1) of a railway vehicle comprising two mounted axles (4) each comprising a pair of wheels (2), at least one motor (25) fixed to the chassis (6) and extending between the wheels (2) of the mounted axle and driving the rotation of said mounted axle (4) by means of a coupling and a reduction gear, one of the axle boxes housing the reduction gear of the motor (25), the motor (25) being free to rotate about a motor axis (M), characterized in that the axis (M) of the motor (25) is located at an altitude (h) lower than an altitude (H) of the axis (E) of the mounted axle (4), the altitude being taken along a vertical axis (Z) perpendicular to the longitudinal axis and to the axle axis (E) from a horizontal plane (P) perpendicular to the vertical axis (Z) and tangent to the wheel (2) in the lower part of the bogie (1).