Low-Speed Tire Uniformity Characterization Through Surface Geometry
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Solution Overview
Problem
Existing devices for characterizing tire uniformity are either expensive and difficult to implement or provide measurements that are hard to interpret, particularly when measuring dynamic loads at high speeds, as they combine various causes of defects.
Innovation Solution
A device and method for characterizing tire uniformity at low speeds using a rotary support with measuring members to detect internal and external surface geometry, converting thickness variations into mass variations based on predetermined density, and generating a mass distribution map to identify and address irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-speed uniformity devices are used to measure dynamic loads at high speed, then the measurements are representative of excitations to the vehicle, but the devices are particularly expensive and difficult to implement and the measurements are difficult to exploit
Solution Approach 1:
The invention changes the operating parameter from high speed to low speed (≤20 rpm), transforming the measurement conditions while maintaining the ability to detect uniformity defects. This parameter change simplifies the device requirements and makes measurements easier to exploit while still providing reliable data about tire defects that affect vehicle excitation.
Solution Approach 2:
The invention creates a simplified copy of the high-speed measurement capability by using low-speed rotation with geometric measurement. Instead of directly measuring dynamic loads at high speed, the system copies the essential information about uniformity defects through geometric measurements at low speed, which can then be used to predict high-speed behavior.
2Device complexity
If low-speed uniformity devices are used to detect defects, then the device is simpler, but the measurements do not make it possible to anticipate all of the dynamic loads at high speeds
Solution Approach 1:
The invention performs preliminary measurement of the tire's geometric characteristics at low speed before the tire is put into high-speed service. By measuring the internal and external surface geometry at low speed, the system captures the static uniformity defects that will later cause dynamic loads at high speed, enabling prediction and compensation.
Solution Approach 2:
The invention transitions from direct dynamic load measurement (force dimension) to geometric measurement (spatial dimension). By measuring the internal and external surface geometry separately and calculating thickness variations, the system accesses uniformity defect information through a different dimensional approach that avoids the complexity of high-speed dynamic measurement.
3Reliability
If high-speed measurements are taken, then dynamic effects are captured, but it is necessary to distinguish between multiple causes combining in the recorded loads
Solution Approach 1:
The invention extracts the geometric characteristics (internal and external surface geometry) as separate, identifiable parameters before they combine into complex dynamic loads. By measuring the tire geometry at low speed and calculating thickness variations, the system separates the various defect sources (mass distribution, geometric irregularities) into distinct measurable quantities that can be individually analyzed and traced to their causes.
Data Source
AI summary
A device (20) for characterizing a tire (10) in terms of uniformity comprises: a frame (22), a rotary support (24) mounted with the ability to rotate relative to the frame (22) and on which the tire (10) is placed and which is intended to be set in rotation at low speed, at least two geometric measuring members (28a, 28b) secured to the frame (22) and positioned respectively in such a way as to measure the internal geometry and the external geometry of the tire (10) simultaneously as the rotary support (24) rotates, a measuring member (29) for measuring the angular position of the rotary support (24) secured to the frame (22), and an electronic control unit (30) configured to retrieve the variations in the internal and external geometry of the tire for each angular position of the rotary support.