Design Of A Railway Hump Car Retarder And Analysis Of The Noise Mechanism

The car retarder is an elementary railway equipment, which is applied to controlcar speed by friction braking and help cars to fit together automatically and safely inrailway hump yard. With the development of railway heavy haulage, in our country,the Ministry of Railways issued a new industry standard which demands that carretarder should be suitable for heavy haul cars with25t axle load and improve theclearance limit for upper part of the retarder. The old car retarder is generallydesigned to meet the transportation demand for cars with21t axle load. The principalquestion of the old equipment in use is the fracture problem of brake caliber. Thenoise of the car retarder has affected physical and psychological health of railwayworkers and residents nearby. As a result, on condition of safety for braking to lightcars, a new retarder should be designed to meet the transportation demand for heavyhaul cars with25t axle load. At the same time, the mechanism of the retarder’s noiseshould be analyzed in order to explore some effective and applicable noise reductionmeasures.The specific content of this paper is listed as follows:1. It is focused on why light cars brake hop during braking of floating rail loadpressure car retarders. Then some corresponding solutions have been proposed.2. According to the new railway standard, this paper has designed T.JK1-D50type car retarder. The method of theoretical calculation has been used to determinethe braking ability of the new equipment, and checked the rationality of theparameters to mitigate light cars’ braking hop. Then it has analyzed the influence ofparameter variations on the noise of the car retarder and figured up its driving airpressure. At last the strength of brake calipers has been checked by finite elementmethod.3. Through experiment test on the friction coefficient between braking rail andthe wheel of cars, the correctness of theoretical calculations has been verified. A25taxle load fatigue test has been performed on main stress parts of T.JK1-D50type carretarder. Good effect has been obtained in2million times test of no-damage so thatthe structure strength and service life of the equipment has been proved. Being putinto use, the new retarders have met railway transportation requirements and reachedthe design object.4. This study has designed a kind of test unit of labyrinth constrained damping layers. Then the noise reduction effects of constrained damping layers and T.JK1-D50type car retarder have been measured separately. The new retarder’s noise has reduced8dB(A). After the frequency and position of the noise were surveyed with an acousticcamera, the result has indicated that the braked wheels are the main noise sources.The braking rails of constrained damping layers have not reduced the incentive to thewheels. Therefore the noise reduction effect wasn’t so obvious. On the base of theexperiment, combing the general research progress of friction-induced noise, it hasanalyzed and confirmed that the mechanism of the retarder’s noise is self-excitedvibration of the wheel-based system. At last the direction of research on the noisereduction of car retarders has been pointed out.