Structure Design And Simulation Study Of Elevator Speed Limiter

Elevator speed governor is an equipment to limit the moving speed of the elevator lift car. When the lift car exceeds the speed limit, the speed governor stops rotating quickly and brakes the lift car through steel wire ropes and safety pincers so as to fully guarantee the safety of passengers and cargoes. Aiming at the existing problems of the current speed limit of elevator, a speed limiter with simple structure was designed, which was used to middle speed elevator. Firstly, according to the working principle of two way speed limiter of the elevator, the design scheme was put forward. The structure of the elevator speed governor and size parameters of each part were then calculated, then the part drawing, assembly drawing were drawn with SolidWorks software, after that, we can make force analysis to main parts of the speed governor using SolidWorks Simulation. According to the results of the analysis and fitting relation among parts, we can modify size parameters, make optimum design to the structure parameters, then obtain the optimal design scheme. Then, we can make motion simulation analysis with SolidWorks Motion, and the results shows that the elevator lift car has the characteristics of simple structure and reliable performance, reaching the purpose that the volume of the elevator lift car is the most small on the premise of meeting the requirements of elevator limited speed. Finally, the process route is drawn up, and the process card is formed for ratchet. The specific research content and the problem were solved as follows:(1)By comparing the properties between pendulum type overspeed governor and centrifugal type overspeed governor, it is discovered that pendulum type overspeed governor is simple in structure, easy to manufacture and low cost in maintenance, so it is usually used for slow speed elevator. On contrary, the centrifugal type overspeed governor is rapid in response and high cost in maintenance, so it is usually used for medium or high speed elevator. Currently, the manufacture of the bidirectional overspeed governor also adopts the method of centrifugal type overspeed governor, which greatly increases the cost in manufacture and maintenance. Aiming at the above mentioned problem, the author proposes the solution of bidirectional overspeed governor based on pendulum type overspeed governor.(2)Through analyzing the structure of unidirectional overspeed governor and using the operational principle of pendulum type overspeed governor, the author has designed the part drawing and assembly drawing of bidirectional overspeed governor by using SolidWorks.(3)By using SolidWorks Simulation, the author has separately made static analysis among the sheave, pendulum and ratching of bidirectional overspeed governor which is specialized for elevator. After receiving the simulation results, the author has further optimized its structure for the purpose of achieving national standard safety factor.(4)The author also made kinematic analysis of the bidirectional overspeed governor by using SolidWorks Motion. Through repeatedly modifying the position and parameter of rate-limiting spring, the free length and elastic coefficient of rate-limiting has been determined.(5)Considering the property of ratcheting, the author has arranged the machining process route which includes the manufacture method of turning、milling、boring and drilling. As for those ratcheting with high ensure requirements, the IT is below 10 degree and the surface roughness is R_a=6.1.