Rail Vehicle Bogie Secondary Spring Positioning for Tight Curves
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Solution Overview
Problem
Existing rail vehicle bogies with cradles are complex in construction and struggle to maintain suspension comfort while allowing large turning angles greater than 6 degrees, which is necessary for tight curve radii in underground, tram, and light rail vehicles.
Innovation Solution
A bogie design that moves the secondary spring's position relative to the bogie frame, allowing it to change its local position along the bogie frame or car body, eliminating the need for a cradle and enabling larger turning angles by using a displaceable or rollable secondary spring with elastomer material and guides that influence its movement and restoring forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cradle is used to allow large turning angles, then the bogie can handle tight curves, but the construction becomes complex
Solution Approach 1:
The patent removes the cradle component from the bogie structure entirely. Instead of using a cradle to accommodate large turning angles, the invention uses a simplified configuration where the secondary spring is directly mounted to the bogie frame, allowing the bogie to achieve large turning angles without the complex cradle mechanism.
Solution Approach 2:
The secondary spring is designed with dynamic positioning capability, allowing it to change its local position on the bogie frame during operation. This dynamic adjustment enables the spring to maintain optimal suspension characteristics while accommodating large turning angles, replacing the need for a static cradle structure.
2Reliability
If a cradle with secondary springs is used, then suspension comfort is provided, but the construction becomes complex
Solution Approach 1:
The patent combines the functions of the cradle and secondary spring into a single integrated mounting arrangement. The secondary spring is directly mounted to the bogie frame, merging the suspension function with the frame connection, thereby eliminating the separate cradle structure while maintaining suspension comfort.
Solution Approach 2:
The secondary spring mounting structure serves multiple functions: it provides suspension comfort, accommodates large turning angles, and simplifies the overall bogie construction. This multi-functional design replaces the specialized cradle structure with a more versatile and simpler arrangement.
3Device complexity
If the secondary spring position is fixed on the bogie frame, then the structure is simple, but large turning angles cannot be accommodated
Solution Approach 1:
The secondary spring is designed with dynamic positioning capability, allowing it to change its local position on the bogie frame during operation. This dynamic adjustment enables the spring to maintain optimal suspension characteristics while accommodating large turning angles, replacing the need for a static cradle structure.
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
This design simplifies the bogie construction, reduces mass, and enhances interior space, while maintaining suspension comfort by allowing the secondary spring to absorb transverse movements and maintain its position during small turning angles, effectively handling larger turning angles without the need for a cradle.
Implementation Method 1
The secondary spring according to the invention is, as is usual for a spring, elastically deformable in order to achieve the spring action
Implementation Method 2
guides that influence its movement and restoring forces
Data Source
Figure 1
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Figure 3
AI summary
Bogie (1) for rail vehicle, comprising a bogie frame (2), at least one elastically deformable secondary spring (13, 14; 30, 31), characterized in that a local position of the secondary spring (13, 14; 30, 31) relative to the bogie frame (2) is changeable, and rail vehicle comprising such a bogie.