Rail Vehicle Chassis Longitudinal Coupling for Unsprung Mass Reduction
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Solution Overview
Problem
Existing running gear systems for rail vehicles face limitations in mobility due to high inertia and unsprung masses, leading to increased wheel wear and noise, especially on curved tracks, and require high actuating forces for active wheel control.
Innovation Solution
The running gear design connects the drive motor/gear unit to the support structure via a coupling element primarily loaded in the chassis longitudinal axis, with separate force and torque transmission, and centrally positions cross-sectional areas in the coupling and clutch elements to reduce twisting torques and introduce longitudinal forces effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the drive motor is supported on the wheelset axle, then the drive motor can be connected to the wheelset, but the inertia and unsprung mass increase, resulting in high load on wheelsets and pronounced wheel wear
Solution Approach 1:
The patent divides the force transmission functions into separate components: the first suspension element handles vertical and lateral forces, while the first coupling element (longitudinal rod) handles only longitudinal forces. This segmentation allows the drive motor to be decoupled from the wheelset axle, reducing unsprung mass and wheel wear while maintaining all necessary force transmission capabilities.
2Device complexity
If the drive motor is supported on the wheelset axle, then the connection is simplified, but the inertia with respect to rotations about running gear vertical axis increases
Solution Approach 1:
The patent extracts the drive motor support from the wheelset axle, removing the source of rotational inertia. The longitudinal rod (first coupling element) is taken out as a separate component that transmits only longitudinal forces, allowing the wheelset to rotate about the vertical axis with minimal inertia resistance.
3Reliability
If active wheelset control system with wheelset positioning devices is used, then driving conditions can be stabilized, but high actuating forces are required to cause rotation of wheelsets
Solution Approach 1:
The patent creates a dynamic system where the wheelset can rotate freely about the vertical axis due to the decoupled mounting arrangement. This dynamic capability reduces the actuating force required for wheelset positioning devices to achieve the same rotational effect, while maintaining driving stability through active control.
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 enhances mobility, reduces mechanical loads and wear on the wheel sets, lowers driving noise, and minimizes actuating forces required for active wheel control, resulting in improved driving comfort and reduced wheel set resistance.
Implementation Method 1
the at least first drive motor-gearbox unit (8) is articulated to the at least one support structure (1) via a first suspension element (9) with elastic properties
Implementation Method 2
the at least first drive motor-gearbox unit (8) is connected to the at least one support structure (1) via a first coupling element (11) which can be loaded predominantly in the direction of a chassis longitudinal axis (12)
Implementation Method 3
at least one first primary spring (6) and a second primary spring (7) between the at least one support structure (1) and the at least one first wheelset (21)
Data Source
Figure 1
AI summary
The invention relates to a chassis for rail vehicles, having at least one support structure (1), at least one first primary spring (6) and a second primary spring (7), at least one first drive motor transmission unit (8), which is connected to the at least one support structure (1) via at least one first suspension element (9), at least one first wheelset (21) and at least one first clutch (19), which is connected to the at least one drive motor transmission unit (8) and to the at least first wheelset (21). To create advantageous construction conditions, the invention proposes that the at least first drive motor transmission unit (8) is connected to the at least one support structure (1) by means of a coupling element (11) that can be loaded primarily in the direction of a chassis longitudinal axis (12). This achieves an advantageous movability of the support structure (1) and the first wheelset (21) relative to each other.