Research On The Elevator Of Roller Opposite Force Type Brake Testers

Automobile braking performance is one of the main characteristics of the vehicle,which is one of the security vehicles and mechanized inspection project and directlyrelated to traffic safety. With the development and improvement of road quality andthe high way and the increasing of vehicle speed, the vehicle braking performancerequirements are also rising. Currently anti-force roller brake tester is widely used inmotor vehicle testing agency for testing vehicle braking performance.At present, China has made some progress in the area researching brakeperformance, and test technology is being maturely. But until now, what is still widelyused is the fixed roller wheelbases, the fixed cylinder diameters and the fixedinstallation height of Roller Opposite Force Type Brake Testers. When doing thevehicle brake performance test, we find that some parts of the wheel state is difficultto keep in a horizontal state because of the difference of the wheels diameters, whichlead to its axle load relative levels of status changes. There are two situations aboutthe changes. It is greater or less than the level of axle load state for two-axle vehicle.Finally it will directly affect the brake performance evaluation results. When testingthe multi-axis vehicle, due to the non-tested vehicle wheels being on the ground andthe connecting relationship and interaction of the connectors between the wheel axles,prone to be tested wheel sidelined trend so that the tested wheel cannot be pressedcompletely on the cylinder and the attached weight is reducing. Even if some vehicleshave a good brake performance, the maximum brake performance will be reducedbecause of the reduction of attached weight, which result in the stage floor axleweight measured by the ratio of (brake rate) difficult to compliance and the wheel cannot accurately detect the braking capacity. Adjust the height of the brake tester duringinstallation, but in any case it cannot make different vehicles’ wheels keep in ahorizontal plane.To solve these problems, this paper has done some analyses on the requiredconditions and its testing process, and adds a elevating device in the original rolleropposite force type brake testers so that the platform can be elevated freely under thesystem control, and achieve the purpose to test accurately. So this paper mainlystudies the following aspects:1. Do some theoretical analyses respectively for the two-axis and multi-axisvehicle axles on the brake performance aspects. Through building mathematicalmodels, analyze the factors that affect vehicle axle load distribution, the relations ofthe axle load size and its relative height when doing two-axle vehicles’ and multi-axisvehicles’ tests on the roller opposite force type brake testers. Analyze the reasons ofthe change that the tested axis load shaft is relative to the ground axle load for the two-axle and multi-axis vehicles, and explore the solution that can ensure axle loadtest shaft and its axle load on the ground is equal during the test, which determined tolay the groundwork for solutions.2. On the basis of multi-axis and the axis gantry mounted brake performancetesting mechanism analysis, analyze the lifting height of Anti-force Rolling BrakeTesting Platform, and then determine the carriage lifting height range. According tolift height, design two lifting program which are vertical lift height and along rampslift. Comparatively analyze the synchronization from lifting, stationary lifting process,the cost after lifting stability and lifting apparatus aspect. By comparing theadvantages and disadvantages of the two programs, determine the final program.3. According to the scheme this article selected, design the lift device specifically.Include the mechanical design and hydraulic system design. The mechanical designincludes a lifting device frame design, the sliding track structure, hydraulic cylinderand lifting machinery support structure design. In the design of the hydraulic system,determine the composition and related parameters of the hydraulic system, select thehydraulic cylinder to meet the requirements and describe the working principle ofhydraulic systems and control theory. To ensure the strength of the lift device meetsthe design requirements, respectively, simulate the stress, displacement, and strainwhich also can verify the reliability of the design of the device.4. Design the computer control system, including hardware and the softwaresystem, to realize the intelligent control of the Roller Opposite Force Type BrakeTesters. In the Hardware designs, determine the system control process and draw thesystem control schematics, and select the models of some relative hardware. And thedesign of system software contains about six modules and some control system’s flowcharts of the control process. To ensure the brake tester can be free lift under thesystem control and detect the vehicle braking performance accurately, the paperachieve a reaction drum brake control station lift.