Rotary Load Cell Layout for Direct Tangential Force Measurement
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Solution Overview
Problem
Current tire uniformity machines face challenges in accurately measuring tangential forces due to indirect evaluation methods and require multiple load cells, leading to complexity and size issues, which complicates the measurement of rolling resistance and tractive force variation.
Innovation Solution
A rotating body load measuring device with a load cell capable of directly measuring forces in the main load direction, central axis direction, and tangential direction, ensuring accurate and compact evaluation by aligning the main load direction with the maximum load measurement direction and using a symmetrical structure to suppress moment generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple load cells are used to measure forces in different directions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple measurement functions into a single load cell by strategically orienting its principal sensitivity axes. The load cell is configured with two principal sensitivity axes at right angles, where one axis measures the vertical load component and the other measures the horizontal load component, eliminating the need for separate load cells for each direction.
Solution Approach 2:
The single load cell performs multiple measurement functions simultaneously. It measures both vertical and horizontal force components on the rotating body, and through phase-sensitive detection, it can distinguish between static loads and dynamic load variations, providing comprehensive measurement capabilities that would otherwise require multiple specialized sensors.
2Device complexity
If a single load cell is used to measure multiple force components, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The load cell is designed with anisotropic sensitivity characteristics, where different directions have optimized sensitivity for specific measurement purposes. The vertical axis has high sensitivity for static load measurement, while the horizontal axis has high sensitivity for detecting tangential force variations. This directional specialization maintains high measurement precision for each force component despite using a single sensor.
Solution Approach 2:
The system employs phase-sensitive detection that analyzes the phase relationship between the applied load and the load cell output signal. By detecting the phase difference, the system can distinguish between vertical and horizontal force components and separate static loads from dynamic variations, maintaining measurement precision through signal processing feedback.
3Measurement precision
If load drum is moved in front-back direction to measure rolling resistance, then rolling resistance evaluation is achieved, but measurement time increases
Solution Approach 1:
The system continuously measures load components during the rotation of the tire without interrupting the rotational motion. The load cell continuously detects force variations as the tire rotates, and the phase-sensitive detection system continuously processes the signals to extract rolling resistance information, eliminating the need for time-consuming back-and-forth movements of a load drum.
Solution Approach 2:
The patent replaces the mechanical measurement method (moving load drum back and forth) with an electrical/electronic measurement method. Instead of physically moving a load drum to apply and remove loads, the system uses a stationary load cell with phase-sensitive detection to electronically extract rolling resistance information from the continuous rotation signal, dramatically reducing measurement time.
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
Enables accurate measurement of forces in all three directions with a single load cell, simplifying the device configuration and enhancing the evaluation of rolling resistance and tractive force variation without increasing size or complexity.
Implementation Method 1
a load cell that measures a load acting on the load wheel or the tire
Data Source
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AI summary
A rotating body load measuring device (100) according to the present invention detects a force acting on a rotating body (30) that is formed in a columnar shape and rotates around a central axis (L60) of a shaft body (60) protruding from a center of an end face, in a state where a main load is applied to the rotating body (30) in a main load direction (P) that is one direction in a radial direction, and includes a load cell (70) having a measurement center (C70) and capable of measuring forces acting in at least three directions with the measurement center (C70) as a reference, in which the load cell (70) is disposed such that the measurement center (C70) and the central axis (L60) overlap when viewed in the main load direction (P), and is connected to the shaft body (60).