Railcar Bogie with Segmented Cross Beam and Elastic Links
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Solution Overview
Problem
Existing bogies for railcars face challenges in maintaining traveling safety while achieving a low floor and weight reduction, as they often compromise on wheel load stability due to asymmetric side sill movement and complex configurations.
Innovation Solution
A bogie design featuring rotatable axles, a cross beam with a plate spring, and elastic links that allow for angular displacement of axles relative to the cross beam, enabling smooth steering and reduced lateral force, while maintaining a low floor and reducing weight through simple configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the left and right side sills are allowed to swing asymmetrically in the vertical direction to prevent wheel load decrease, then wheel load stability is improved, but lateral force from the track increases causing derailment risk
Solution Approach 1:
The bogie frame is segmented into a cross beam and two side sills that can move independently. The side sills are connected to the cross beam via bearings, allowing them to swing asymmetrically in the vertical direction to follow track irregularities, preventing wheel load decrease while the cross beam remains relatively stable to control lateral force
Solution Approach 2:
Bearings are introduced as intermediary components between the cross beam and side sills. These bearings enable the side sills to rotate about a rotation axis in the car width direction, allowing vertical movement to accommodate track irregularities without directly transmitting lateral forces to the wheelsets
2Reliability
If a complex bogie frame configuration is used to secure traveling safety, then traveling safety is improved, but weight reduction cannot be realized
Solution Approach 1:
The bogie frame is divided into functional segments: a cross beam for structural support and two side sills for wheelset support and movement. This segmentation allows each component to be optimized for its specific function, reducing overall complexity and weight while maintaining safety
Solution Approach 2:
The side sills are designed to be dynamically movable relative to the cross beam through bearings, allowing them to swing in the vertical direction. This dynamic capability enables the bogie to adapt to track irregularities, improving traveling safety without requiring a complex rigid structure
3Adaptability or versatility
If the side sills are supported by the cross beam to rotate about a rotation axis, then followability of wheels with respect to the track improves, but the configuration becomes complex
Solution Approach 1:
The bogie is segmented into a cross beam and side sills with bearings at specific locations. This segmentation creates a simple rotational mechanism where side sills can swing independently about a rotation axis, improving wheel followability without complex control systems
Solution Approach 2:
The side sills are designed with rotational freedom about an axis extending in the car width direction. This dynamic capability allows the wheels to naturally follow track irregularities through passive mechanical movement, achieving high adaptability with minimal structural complexity
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 bogie design effectively prevents wheel load decrease and lateral force, ensuring traveling safety and weight reduction while maintaining a low floor and smooth ride quality.
Implementation Method 1
a plate spring extending in a car longitudinal direction in a state where a first end portion of the plate spring is supported by the first axle box, and a second end portion of the plate spring is supported by the second axle box, the plate spring supporting the pressing member from below so as to be displaceable relative to the pressing member
Implementation Method 2
a first upper link extending in the car longitudinal direction to connect the cross beam and the first axle box and including a first end portion elastically coupled to the first axle box; a first lower link extending in the car longitudinal direction to connect the cross beam and the first axle box and including a first end portion elastically coupled to the first axle box
Data Source
AI summary
A bogie includes: a plate spring extending in a car longitudinal direction in a state where a first end portion of the plate spring is supported by the first axle box, and a second end portion of the plate spring is supported by the second axle box, the plate spring supporting the pressing member from below so as to be displaceable relative to the pressing member; a first upper link connected to the cross beam and the first axle box and including a first end portion elastically coupled to the first axle box; a first lower link connected to the cross beam and the first axle box and including a first end portion elastically coupled to the first axle box; a second upper link connected to the cross beam and the second axle box and including a first end portion elastically coupled to the second axle box; and a second lower link connected to the cross beam and the second axle box and including a first end portion elastically coupled to the second axle box, a coupling point where the first end portion of the first upper link and the first axle box are coupled to each other and a coupling point where the first end portion of the first lower link and the first axle box are coupled to each other being arranged on a first virtual straight line passing through a center of the first axle in a side view, a coupling point where the first end portion of the second upper link and the second axle box are coupled to each other and a coupling point where the first end portion of the second lower link and the second axle box are coupled to each other being arranged on a second virtual straight line passing through a center of the second axle in the side view.