Variable Axle Geometry for Rail Vehicle Wear Reduction
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Solution Overview
Problem
Existing rail vehicle systems face challenges in minimizing wheel-rail contact forces, leading to profile wear and rolling contact fatigue, which can cause damage and require costly maintenance, as they often rely on complex transverse actuators to achieve optimal wear behavior.
Innovation Solution
A rail vehicle with variable axle geometry that allows for continuous and independent angular displacement of axles using actuators, eliminating the need for complex transverse actuators by adjusting horizontal angles to achieve optimal angular position and transverse displacement, thereby optimizing wear behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If complex transverse actuators are used to achieve optimal wear behavior, then wheel-rail contact forces are minimized, but device complexity increases
Solution Approach 1:
The patent extracts the transverse actuation function from the traditional lateral actuator and integrates it into the existing longitudinal actuator system. The longitudinal actuators that already exist for axle displacement are made to perform both longitudinal and transverse functions through coordinated control, eliminating the need for separate complex transverse actuators.
Solution Approach 2:
The existing longitudinal actuators are designed to perform multiple functions: both longitudinal displacement of axles and transverse displacement through coordinated asymmetric operation. This multi-functionality reduces the overall number of actuators and simplifies the device complexity while maintaining the capability to minimize wheel-rail contact forces.
2Manufacturing precision
If multiple actuators are used to achieve precise axle positioning, then angular position and transverse displacement are optimized, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple actuators into a reduced set. By coordinating the operation of longitudinal actuators on different axles, the system achieves both precise angular positioning and transverse displacement control that would traditionally require separate actuators, thereby reducing the total number of actuators needed.
Solution Approach 2:
The system uses dynamic coordination of actuator operations to achieve precise positioning. The longitudinal actuators are controlled in a coordinated manner where their asymmetric operation produces both angular and transverse effects, allowing precise axle positioning with fewer actuators through dynamic control strategies.
3Loss of energy
If traditional radial steering is used to reduce lateral forces, then frictional power is reduced, but rolling contact fatigue damage accumulates
Solution Approach 1:
The patent implements dynamic adjustment of axle angles and positions that goes beyond fixed radial steering. The system continuously adapts axle geometry to optimize both friction reduction and fatigue mitigation by controlling not only the radial position but also the angular orientation of axles, allowing the wheelset to negotiate curves in a manner that reduces both sliding friction and contact fatigue.
Solution Approach 2:
The system changes multiple geometric parameters simultaneously (axle angle, lateral displacement, longitudinal position) rather than relying on a single parameter adjustment. This multi-parameter control allows the system to optimize the wheel-rail contact conditions to reduce both frictional power loss and rolling contact fatigue damage by creating more favorable contact patterns during curve negotiation.
Data Source
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AI summary
The vehicle (S) has axles (A1) i.e. wheel sets, rotatably supported around a rotating point, and actuators (AKT1, AKT2) connected to sides of the axles, respectively, where ends of the actuators are connected with a frame of the vehicle. Horizontal angle positions (alpha1, alpha2) of the respective axles opposite to the frame are adjusted by modulation of lengths of the actuators during the operation of the vehicle, such that a preset transverse displacement and a preset shaft angle (dalpha) are achieved, where the displacement and the angle are determined by a model-based method.