Railcar Bogie Plate Spring Steering via Asymmetric Axle Box
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing railcar bogies are heavy and costly due to numerous welded portions, and while some propose steering devices, they complicate the structure and do not effectively improve curved line traveling performance.
Innovation Solution
A railcar bogie design that omits side sills, featuring a cross beam with wheels and axles aligned in the railcar width direction, using elastic members and plate springs with inclined supporting surfaces to increase the wheelbase on the inside rail for improved steering and stability during curved travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If side sills are included in the bogie frame with welded connections, then the structural strength and stability are improved, but the manufacturing cost increases and the weight becomes heavy
Solution Approach 1:
The patent removes the side sills from the traditional bogie frame structure, extracting the problematic welded connections while maintaining structural integrity through alternative design. The cross beam and axle boxes form the frame without requiring side sills, eliminating numerous welded joints and reducing manufacturing complexity and cost.
Solution Approach 2:
The bogie frame is segmented into distinct functional components: the cross beam for structural support and the axle boxes for wheel mounting, connected through rigid fixtures rather than continuous welding. This segmentation allows each component to be manufactured separately and assembled with fewer connections, reducing both weight and manufacturing cost.
2Reliability
If a steering device with link mechanism is added to improve curved line traveling performance, then the traveling stability is improved, but the structure becomes complex
Solution Approach 1:
The patent implements steering functionality through dynamic geometric changes rather than complex mechanical linkages. The asymmetric positioning of axle boxes relative to the cross beam creates different wheelbase lengths for curved travel, allowing the bogie to steer naturally through geometry rather than active mechanical steering devices.
Solution Approach 2:
The bogie structure itself provides the steering function through its asymmetric configuration. The cross beam and axle box arrangement automatically creates the necessary wheelbase differential for curved line travel, eliminating the need for separate steering mechanisms and their associated complexity.
3Reliability
If the wheelbase is increased on the inside rail side for steering, then the curved line traveling performance is improved, but the bogie structure becomes more complex
Solution Approach 1:
The patent employs asymmetric positioning of the axle boxes relative to the cross beam, placing them at different longitudinal positions. This creates different wheelbase lengths when the railcar travels on curved lines, with the inside rail having a shorter effective wheelbase and the outside rail having a longer wheelbase, enabling natural steering without additional 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 design results in a lightweight bogie with a simple configuration that enhances curved line traveling performance by increasing the wheelbase on the inside rail, improving steering and stability while maintaining a cost-effective manufacturing process.
Implementation Method 1
both the plate spring portion and the supporting surface are movable relative to one another
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A railcar bogie (100) according to the present invention includes: a cross beam (31) configured to support a carbody (101) of a railcar; wheels (10) arranged at both railcar width direction sides of the bogie to be lined up in a railcar longitudinal direction at each of the sides; a pair of front and rear axles (11) respectively arranged at a front side and rear side in the railcar longitudinal direction so as to sandwich the cross beam (31) and extend in a railcar width direction, each of the axles (11) connecting the wheels (10) located at a left side and right side in the railcar width direction; bearings (12) arranged at both railcar width direction sides of each of the axles (11) and configured to rotatably support the axle (11); axle box portions (20) coupled to the cross beam (31) via elastic members and each configured to store the bearing (12); and plate spring portions (40) extending in the railcar longitudinal direction so as to respectively support both railcar width direction end portions of the cross beam (31), both railcar longitudinal direction end portions of each of the plate spring portions being respectively supported by the axle box portions (20). Each of the axle box portions (20) includes a supporting surface (26) that supports the plate spring portion (40) such that the plate spring portion (20) is relatively movable and that is inclined toward a longitudinal direction middle portion of the plate spring portion.