Research On Performance Of Car Braking Device On C80 Railway Freight

The structure of the C80 aluminum alloy gondola is different from other trucks due to the structure of the bathtub under the vehicle.During the operation,problems such as poor relief,fast wheel tread wear,uneven brake shoe wear,and breakage of the brake beam column were found,which seriously affected operational safety.Through the combination of theoretical analysis,field test and simulation test,the attitude and stress state of each component of the brake device are analyzed and predicted,and an improvement plan is proposed.First,through analytical calculations,the main parameters such as braking efficiency and resistance mitigation of the C80 unit braking device are theoretically calculated,and the stress analysis of the main stressed parts of the braking device is performed.Then,the Recur Dyn multi-body dynamics simulation platform is used to create a virtual prototype of the braking device,and the simulation model is revised in conjunction with the field measurement data.Finally,the verified simulation model is used to predict and improve the performance of the braking device of the C80 unit of the empty and heavy vehicles under various working conditions.The main research content and results include:The maximum deviation between the simulation test results of the C80 unit braking device and the field test is less than 5%,and the braking and mitigation processes and conditions are consistent with the field test.The effectiveness of the C80 unit braking device simulation model based on the Recur Dyn environment is demonstrated.Provide a reliable simulation model for effectively predicting the performance of the C80 unit braking device.Theoretical analysis finds that the lever-biased brake device is likely to cause a large torque at the brake beam column,and the column may be damaged due to long-term action.After the optimization of lever weight reduction,the pressure of the lever weight on the brake beam column is reduced by more than 60%.After canceling the braking force,the residual brake shoe pressure is less than 50 N,which effectively improves the relief performance of the C80 unit brake device.In the braking state,the brake shoe of the C80 unit brake device is unevenly stressed,which is prone to abnormal wear.The lateral displacement of the brake beam tends to increase with the increase of the gap.There is a large residual brake shoe pressure in the minimum clearance condition,which alleviates poor performance.Taking measures to reduce the pin shaft by 1mm on site will help improve the braking device to alleviate the problem,but it will cause the empty brake braking efficiency to become lower due to the larger gap.It is recommended to adjust the relationship between the iron and the brake adjuster to adapt the problem of insufficient braking force due to the clearance change.When the brake is running in a curve,the brake shoe is subjected to severe stress and large fluctuations,and there is shock and vibration.As the turning radius gradually decreases,the residual pressure on the brake shoe will become larger.The brake beam has a phenomenon of reverse running toward the vehicle,and there is abnormal contact between the brake shoe and the wheel.As the speed increases,this phenomenon tends to intensify,and it is easy to cause abnormal wear of the wheels and uneven wear of the brake shoes.The analysis of the rigid-flexible dynamic stress shows that the contact stress on the side of the brake shoe close to the rim is greater.During the braking process of the 2nd brake shoe and the 3rd brake shoe,a large contact stress appears at the lower part of the brake shoe,which may easily cause the brake shoe to wear.The stress at the turning point of the crank arm is relatively high,and it is necessary to pay attention to whether there is a crack at this place.The brake lever and the bracket and its contact with the brake regulator,the vertical brake lever bend and its connection with the floor,the swimming(fixed)lever and the brake beam column and the middle tie rod have a large stress,on-site maintenance needs to focus on checking wear.The above research results provide a theoretical and technical reference for the upgrading of C80 and other railway freight cars,and provide a new technology for discovering the operating rules and performance improvement of railway freight car brakes and other mechanisms.