Research on the Friction Loss of a Loading Brake Tester with Adjusted Shaft Distance

A friction loss model for a loading brake tester with adjusted shaft distance was constructed to correct the test results of the braking rate of the loading shaft, which could largely improve the accuracy of automobile braking performance tests. Specifically, the influence of tire pressure, vehicle axle load, placement angle, and vehicle speed on the friction loss was tested and analyzed on the tester. The friction loss model for the tester was constructed based on the first defined relative slip and placement angle, which was validated through actual tests on four types of vehicles. The results showed that the maximum relative error between the simulation and the measured values is 2.2%, indicating the friction loss model is valid and can provide a basis for correcting the braking force of automobile brakes. Meanwhile, the maximum braking force increased from 3982 N to 4772 N, increased by 19.8%, when the placement angle was raised from 36.9° to 47.0°, demonstrating the effectiveness of constructing a friction loss model and enhancing the accuracy of the loading brake tester with adjusted shaft distance test results. Accordingly, in order to improve the detection accuracy of the self-developed tester, the friction loss model is essential for correcting the friction loss caused by the change in the placement angle, and then the braking rate of the vehicle should be determined according to the relevant regulations stipulated in China, EU, USA, Japan, and other countries or regions, which can accurately reflect the performance of the vehicle’s braking system.