Bogie Trailing Arm Axis Arrangement for Low Floor Height
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Jakobs bogies in rail vehicles face challenges in achieving low floor heights due to the need for accommodating wheel sets, drive motors, and braking devices, which results in a large overall height and increased installation space requirements, especially in the vertical direction.
Innovation Solution
The arrangement of the axes of rotation of the bearings is optimized to reduce the overall height, allowing for a more compact connection between the bogie and car body, with a trailing arm design that minimizes vertical space requirements and allows for lower force application points, reducing erecting moments and enabling a more compact and resilient design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bogie accommodates wheel sets, drive motors, and braking devices, then the bogie can perform its function, but the overall height increases
Solution Approach 1:
The patent repositions the trailing arm connection point on the bogie frame from a higher position to a lower position, utilizing the vertical dimension more efficiently. This dimensional repositioning allows the trailing arm to connect at a point that reduces the overall height requirement while still accommodating all necessary bogie components (wheel sets, drive motors, braking devices) in the available space.
2Strength
If the trailing arm is made more resilient to handle greater vertical loads, then the load capacity increases, but the installation space requirement increases
Solution Approach 1:
The patent applies local quality by making the trailing arm resilient specifically in the vertical direction where load capacity is needed, while maintaining a compact profile in the horizontal direction. The trailing arm is designed with localized reinforcement and appropriate material properties to handle vertical loads effectively without requiring increased horizontal dimensions, thus minimizing installation space requirements.
3Ease of operation
If the floor of the car body is lowered to achieve low-floor vehicle, then passenger accessibility improves, but the space for accommodating bogie components becomes insufficient
Solution Approach 1:
The patent resolves this contradiction by optimizing the vertical positioning of the trailing arm connection point on the bogie frame. By connecting the trailing arm at a lower position on the bogie, the design creates additional vertical clearance above the bogie components, which can be utilized to lower the car body floor while still accommodating all necessary bogie components in the available space.
4Stability of the object's composition
If the force application points of the trailing arm are arranged lower on the car body and bogie, then the erecting moments are reduced, but the structural design becomes more complex
Solution Approach 1:
The patent applies inversion by reversing the conventional approach: instead of positioning the trailing arm connection point high on the bogie frame and accepting larger erecting moments, the design connects the trailing arm at a lower position on the bogie. This inverted positioning naturally reduces the lever arm and consequently the erecting moments, improving operational behavior while the structural complexity is managed through straightforward structural adaptations.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The bogie linkage has two railcar bodies (27,28) whose ends rests on the articulated bogie. A flexible coupling is provided for articulated connection of the railcar bodies. The longitudinal link (13) interconnects one of the railcar bodies (28) and a bogie frame. One of the axis of rotation (29) of the supports (15,19) extends in vertical direction extends.