Tire Tester Universal Joint Load Measurement
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Solution Overview
Problem
Existing tire testers face difficulties in accurately measuring loads due to the simultaneous action of lateral force, rolling resistance, and pressing load on the piston rod, which complicates the measurement of individual forces.
Innovation Solution
A tire tester design that includes a rotary mechanism with a universal joint support shaft, allowing for independent measurement of lateral force and rolling resistance by positioning the shafts to minimize mechanical losses and errors, enabling accurate load component measurement in predetermined directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If three load cells are used to measure lateral force, rolling resistance, and pressing load simultaneously, then all three forces can be measured at the same time, but the measurement accuracy deteriorates due to mutual interference between the forces
Solution Approach 1:
The measurement function is segmented into two independent parts: a universal joint mechanism that mechanically separates the measurement of lateral force and rolling resistance, and a separate pressing load measurement system. This segmentation eliminates mutual interference between force measurements while maintaining efficient simultaneous operation.
Solution Approach 2:
The universal joint acts as an intermediary mechanism between the tire and the measurement systems. It mediates the transmission of lateral force and rolling resistance to their respective sensors while preventing cross-contamination of force components, thereby improving measurement accuracy without sacrificing measurement efficiency.
2Measurement precision
If load sensors are attached to the hub for measurement, then direct load measurement is achieved, but the device complexity and difficulty of application to various tire types increases
Solution Approach 1:
The load measurement function is extracted from the tire hub and relocated to the tire support mechanism. By removing the need for hub-mounted sensors and placing measurement points on the support structure instead, the system achieves accurate load measurement while significantly reducing device complexity and improving adaptability to different tire types.
Solution Approach 2:
The tire support mechanism is designed with universal functionality to accommodate various tire types without requiring hub modifications. The measurement system leverages the support mechanism's structural properties to measure loads universally across different tire configurations, enhancing both simplicity and adaptability.
3Device complexity
If the piston rod directly supports the tire for rotation, then the structure is simplified, but the ability to accurately measure individual load components deteriorates due to simultaneous force action
Solution Approach 1:
The support structure is segmented into functional components: the piston rod maintains its simple role of supporting tire rotation, while the universal joint and measurement mechanism segments handle the complex task of separating and measuring individual load components. This segmentation preserves structural simplicity while achieving precise measurement.
Solution Approach 2:
The universal joint serves as an intermediary between the simple piston rod support and the measurement system. It allows the piston rod to remain structurally simple while enabling accurate decomposition and measurement of load components through the joint's mechanical properties.
Data Source
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AI summary
To measure components of a load acting on a tire in a predetermined direction with accuracy, a tire tester 1 includes a rotary member 102, a measurement mechanism 250, and an actuator configured to advance and retreat the measurement mechanism 250 with respect to the rotary member 102. The measurement mechanism 250 includes an axle 253, a main frame 251 connected with the actuator, a subframe 252, and a measurement unit 255. The axle 253 extends in an X direction and supports a tire T to be rotatable. The subframe 252 supports the axle 253 and is attached to the main frame 251 such that the subframe 252 is rotatable around a shaft 254b extending along a Y direction. The measurement unit 255 is provided between the main frame 251 and the subframe 252.