Tire Testing Machine Torque Cancellation for Rolling Resistance
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Solution Overview
Problem
Conventional tire testing machines measure rolling resistance with inaccuracies due to rotational friction torque from bearings, leading to differences between measured and actual rolling resistance, making precise measurement challenging.
Innovation Solution
A tire testing machine with a torque canceller that separately imparts a counteracting torque to the spindle shaft to cancel the rotational friction torque, using a motor and control unit to adjust the generated torque based on measured rotational friction torque, ensuring the spindle shaft operates in a state of freely rolling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the spindle shaft is rotatably supported through a bearing in the housing, then the spindle shaft can rotate to enable tire testing, but a rotational friction torque is generated in the spindle shaft by the bearing, causing measurement inaccuracy
Solution Approach 1:
The patent extracts and separates the harmful rotational friction torque from the measurement system. By providing a torque canceller that independently applies counter-torque to the spindle shaft, the harmful friction torque generated by the bearing is removed from the measurement chain, allowing accurate measurement of tire rolling resistance without the bearing friction interference
Solution Approach 2:
The torque canceller acts as an intermediary device between the bearing friction source and the measurement system. It introduces a compensating torque through the spindle shaft that mediates and cancels the harmful friction torque, enabling the measurement system to obtain accurate rolling resistance values despite the presence of bearing friction
2Measurement precision
If a theoretical correction method using a transformation matrix is applied to eliminate rotational friction torque impact, then the measurement value can be adjusted, but the tire is not in the original state of freely rolling and the correction is only theoretical, making high precision measurement difficult
Solution Approach 1:
The torque canceller enables the measurement system to self-correct for bearing friction torque in real-time during actual tire rolling. By continuously monitoring the friction torque and applying compensating torque through the spindle shaft, the system maintains the tire in its natural freely-rolling state while automatically eliminating measurement errors, achieving both high precision and practical applicability
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 approach allows for precise measurement of rolling resistance by eliminating the impact of rotational friction torque, thereby improving measurement accuracy and aligning the testing conditions with the actual state of freely rolling tires.
Implementation Method 1
using a motor and control unit to adjust the generated torque based on measured rotational friction torque
Implementation Method 2
a rotational friction torque is unavoidably generated in the spindle shaft by rotational friction of the bearing
Data Source
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AI summary
Provided is a tire testing machine capable of measuring a force generated in a tire with high precision. The tire testing machine includes a spindle shaft (20) for holding a tire (T), a housing (22) for rotatably supporting the spindle shaft (20) through a rolling bearing (25), a running device (10) having a surface rotated by rotational driving and imparting a rotational force to a tire contacting the surface, and a measurement device (4) which is provided in the housing (22) and measures a force and moment generated in the spindle shaft (20) when the tire (T) is running. Furthermore, the tire testing machine includes a torque canceller (5) for preventing the spindle shaft (20) from such an impact that rotational, friction torque (My1) generated by rotational friction, which is received by the spindle shaft (20) in the housing when the spindle shaft (20) rotates, is imparted onto the shaft (20). The torque canceller (5) is equipped with a motor (30) for the spindle shaft, which imparts a torque for cancelling the impact of the rotational friction torque (My1) to the spindle shaft (20).