| There will be lots of work of maintenance and construction in the railway fields because of wide area and intense railroads. As a result, large machinery has become popular. Tamper, the core equipment of tamping vehicle, is good at completing the work. The stones, which are excited by the squeeze and compaction device, flow in compact sequence under the bed ballast. Finally, fast trains have a good performance. At present, there are three main kinds of tampers on market from USA, Switzerland, Austria. Forced mechanical vibration technology is applied on these products which will reduce the life of tamping ends. So innovative design of tamper has an significance along with the development of tamper in China.A new type of tamper is proposed in the paper based on present products in the world. When product works, vibration and squeeze motion are separate. The vibration is realized by exciter used in the tamper. The operation principle of new tamper is studied at first. The three-dimension model and kinetic simulation are finished along with finite element analysis. A new type of rotary valve with high speed and minute-displacement double-rod cylinder are proposed. The dynamic properties are studied with the use of MATLAB/Simulink. The analysis of flow field of cylinder is finished by computation fluid dynamic software. At last, test rig design and plan of experiment are carried out.The studies are included as follows,In chapter 1, the research background, structure and characteristics of three main kinds of tamping device are formulated, as well as the current development state of tamping device. Then here come researches on the excitation technology applied on tamper. Finally the significance and research content of this subject are discussed.In chapter 2, a new type of tamping device is proposed and operation principle is formulated. The three-dimension model and kinetic simulation are finished with the use of CAX, which helps to study the relation between structural and performance parameters. As a result, the design of electrohydraulic exciter is determined. The statics, modal and non-linearity analyses are carried out.In chapter 3, a new type of electrohydraulic exciter is proposed based on the tamper. Operation principle is formulated. The designs of rotary valve and cylinder are carried out. The rotation of valve is realized by stepper motor. The compact between piston and wall is removed by the application of the auto-limitation structure of cylinder.In Chapter 4, the simulation model of electrohydraulic exciter is established with use of MATLAB/Simulink after the simplification. The relations between frequency of valve, conducting width of valve port, the number of ports of cylinder and dynamic characteristics of exciter are studied respectively, which do help to improve the design of valve and cylinder.In chapter 5, the flow field of cylinder with high frequency is studied with the use of Fluent. The pressure and velocity fields of different working positions and cross sections are studied. The study of cavitation erosion, air cavity and spiral vortex in the flow field of cylinder which bring in the noise and energy-loss is finished.In chapter 6, in order to verify the performance of electrohydraulic exciter as well as the relation between structural parameter and property, the design and machine of test rig are being carried out. The test rig is laid on the test platform of hydraulic part in SKL of ZJU. The mechanic part, hydraulic system, load model system, measurement and data acquisition system are designed. The product choosing is finished. At last, the experiment plan is determined.In Chapter 7, conclusions are given and new views are put forward in the future. |
PDF Full Text Request