Rail Vehicle Wheel Force Measurement via Bogie Frame Strain Gauges
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Solution Overview
Problem
Existing rail vehicle measurement technologies for wheel contact forces are expensive, complex, and require frequent maintenance due to strain gauge damage from movement, and they are not designed for continuous monitoring across all wheel axles.
Innovation Solution
Applying strain gauges to motionless elements of the bogie frame, such as the DG frame, which is protected from spring movements and stone chipping, and using resistance, piezoelectric, or inductive gauges to measure wheel contact forces, with an evaluation unit converting signals into actionable data for safety and maintenance optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauges are mounted on moving parts (shackles) to measure wheel contact forces, then measurement capability is achieved, but the strain gauges are damaged by continuous movement causing kinking or plastic deformation in cables
Solution Approach 1:
The patent introduces an intermediary element (the bogie frame) that remains stationary while still enabling measurement of wheel contact forces. The strain gauges are mounted on the bogie frame rather than on moving shackles, acting as a stable intermediary that transfers the measurement function from moving parts to stationary structure.
Solution Approach 2:
Instead of mounting strain gauges on moving parts (traditional approach), the patent inverts the approach by mounting them on stationary parts (bogie frame). This reversal of the mounting location eliminates the movement-related damage while preserving measurement capability through alternative measurement points.
2Measurement precision
If extensive measurement equipment is installed on selected wheelsets to achieve precise wheel contact force measurements, then measurement accuracy is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent makes the bogie frame serve multiple functions: it acts as both the structural support for the wheelset and the mounting platform for strain gauge measurement. This multi-functionality eliminates the need for separate, complex measurement equipment on each wheelset, reducing overall device complexity while maintaining measurement precision.
Solution Approach 2:
The patent merges the measurement function with the existing bogie frame structure. Instead of adding separate measurement equipment to each wheelset, the strain gauges are integrated into the bogie frame, combining the structural and measurement functions into a single system.
3Measurement precision
If strain gauges are positioned close to wheel axles to capture accurate measurements, then measurement sensitivity is improved, but vulnerability to stone impacts and damage from spring movements increases
Solution Approach 1:
The patent transitions the measurement location from the horizontal plane near the wheel axles to the vertical dimension of the bogie frame structure. By positioning strain gauges on the bogie frame at a different spatial dimension, the system maintains measurement sensitivity while avoiding the harmful environment near the wheels.
Solution Approach 2:
The bogie frame serves as an intermediary structure that transmits wheel contact force information to the strain gauges without exposing them to direct damage from stones and spring movements. The frame mediates between the measurement requirement and the protection requirement.
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 solution provides a robust, low-maintenance, and cost-effective means to continuously monitor wheel contact forces, reducing maintenance needs and enabling early detection of wheel damage and derailment risks, while allowing remote monitoring and optimized maintenance.
Implementation Method 1
The measuring principle is based on strain measurements using strain gauges mounted directly on the wheels of the wheelsets
Implementation Method 2
Applying strain gauges to motionless elements of the bogie frame, such as the DG frame, which is protected from spring movements and stone chipping, and using resistance, piezoelectric, or inductive gauges to measure wheel contact forces
Implementation Method 3
Applying strain gauges to motionless elements of the bogie frame, such as the DG frame, which is protected from spring movements and stone chipping, and using resistance, piezoelectric, or inductive gauges to measure wheel contact forces
Data Source
Figure 1~2
AI summary
A device (16) for measuring wheel vertical forces (Q1Q8) of a wagon (17), the wagon (17) comprising an underframe (18) and at least two bogies (19) with bogie frames (27). The at least two bogies (19) are coupled to the underframe (18) and each have at least two axles which are mounted via a spring system and have wheels (21). The device (16) comprises at least four strain meters (22a-d, 22e-h) per bogie (19) and one evaluation unit (23) per wagon (17), said evaluation unit being coupled to the strain meters (22a-d). The strain meters (22a-d) are applied to the bogie frames (27), which remain immobile during a spring movement of the axle.