Transverse And Longitudinal Modal Analysis And Experimental Study Of High-speed Elevator

The height and number of high-rise and super high-rise buildings are constantly updated,which forces the speed of the elevator to increase day by day.With the increase of the demand for the speed of the elevator,the requirements for the comfort of the elevator are also higher and higher.While the speed of the elevator is speeding up,the vibration problem is becoming more and more serious.The vibration of high-speed elevator in the operation process is mainly divided into vertical direction and horizontal direction.The vertical vibration is mainly caused by the unbalanced rotation of the traction machine,and its traction system is impacted by external dynamic load,which directly affects the operation safety of the elevator;the horizontal vibration of high-speed elevator mainly comes from the manufacturing error of its guidance system.When the high-speed elevator is running,if the mechanical vibration peak value exceeds the maximum bearing amplitude of parts,it will affect the accuracy of precision instruments,damage parts,shorten the service life of the machine,and then affect the normal operation of the elevator,causing huge safety problems.At the same time,the elevator horizontal vibration will directly affect the comfort of passengers in the elevator.Severe horizontal vibration will cause passengers to feel pressure in their ears when taking the elevator,and mechanical noise will cause adverse physiological reactions such as dizziness,dizziness and palpitation.Therefore,in order to explore the vibration characteristics of high-speed elevator in the longitudinal and transverse directions,this thesis mainly studies the following contents:(1)Aiming at the longitudinal vibration caused by the time-varying characteristics of the high-speed elevator lifting system and the horizontal vibration caused by the error of the guiding system,the structure of the high-speed elevator lifting system is summarized firstly.On this basis,the traction system of the high-speed elevator is simplified as a mass spring damping system.Considering the elevator travel problem,based on the energy method and the concentrated mass method,a high-speed elevator model considering the equivalent stiffness of the traction rope is established Furthermore,the structure and function of the guidance system are introduced.Aiming at the horizontal vibration of the car system caused by the guidance system excitation,the dynamic model of the high-speed elevator car rail system is established,and on this basis,the Lagrange energy method is used to establish the dynamic equation of the horizontal vibration of the car system under the influence of the rail excitation The analysis of longitudinal vibration characteristics lays the foundation.(2)Based on the vertical vibration model of the lifting system established in the second chapter,Laplace transform is used to transform it into frequency domain for analysis;secondly,the natural frequencies of each order of the high-speed elevator lifting system are analyzed,and the influences of the vibration damping rubber of the traction machine,the connecting spring of the car top wheel and the car frame,the vibration damping rubber of the car frame and the spring stiffness of the traction rope head on the natural frequencies of each order of the elevator are explored respectively It is proved that the spring stiffness of the traction rope head has the greatest influence on the vertical vibration of the elevator system,which can provide theoretical guidance for the vertical vibration reduction of the elevator.(3)Based on the lateral vibration dynamic model of the coupling between the guide rail excitation and the car,the influence of the structural parameters of the system on the natural vibration characteristics of the elevator car is explored,so as to guide the vibration reduction design and product development of the elevator.Firstly,considering the first four natural frequencies which have great influence on the transverse vibration of the car,the influence of different car load changes and elevator parts parameters on the natural characteristics of the elevator is explored.Furthermore,the acceleration time-frequency response of the lateral vibration of the elevator excited by the guide rail and the vibration energy distribution of the first four natural characteristics of the elevator are analyzed.Finally,the change of car load mainly affects the first natural frequency,the stiffness of guide shoe mainly affects the first and second natural frequencies,and the stiffness of damping pad mainly affects the third and fourth natural frequencies.This study can provide a theoretical basis for the vibration reduction design and optimization of high-speed elevator.(4)Taking the 4m/s high-speed elevator structure parameters of the cooperative company(Shandong Fuji Control Elevator Co.,Ltd)as the input parameters of the elevator transverse and longitudinal dynamic model in Chapter 2,the acceleration time-frequency numerical simulation of the elevator system is carried out.Then,with the help of the existing 120 m high-speed elevator test tower of the cooperative company,a 4m/s high-speed elevator transverse and longitudinal vibration test platform was built and applied DT-4A elevator acceleration tester measures the vibration acceleration at the center of the car floor;finally,the measured elevator acceleration data is analyzed in time-frequency domain,and compared with the typical numerical characteristics of acceleration after numerical simulation,which verifies the correctness of the model established in this thesis and the feasibility of the research method.