Simulation Study On The Performance Of Hoist Mechanism Of Electric Mining Shovel

Cable shovels are widely used in large-scale surface mining operations due to their longevity, high productivity and high break-out forces. With the rapid development of the economy, the market demand of the cable shovel is in the substantial growth at home and abroad, and the demand for larger sizes of bucket to increase sharply. In order to develop larger cable shovels, empirical method can not fully meet the design requirements, therefore, application of modern design method for large mining excavator simulation has become very necessary.In this paper, the virtual prototype models have been created to simulate the performance of hoist mechanism of the Taiyuan Heavy Industry WK-55 shovel by integrating UG NX and MSC ADAMS, and the models of hoist wire ropes and suspension wire ropes are created, which are composed of a lot of discrete rigid cylinders and flexible connections. With the virtual prototype, dynamic simulation and analysis are carried out. This study includes the following five parts:1. Kinematic analysis of the hoist mechanismStruggle to make the most efficient loading and the least digging resistance of the bucket, the paper had analyzed the ideal trajectory of the bucket's tooth tip, and obtained the ideal bucket's digging trajectory curve, namely logarithmic spiral. Then make the kinematic analysis and calculation on the push and hoist mechanism respectively to get the corresponding kinematic parameters to ensure that the bucket can dig in the ideal trajectory.Meanwhile, the kinematic parameters of rotation mechanism were determined according to the performance parameters of the physical prototype.2. Create the simulation model of the hoist mechanismThe geometric models of the working implement's main components were created by the UG NX software, and then the model was imported into the ADAMS/View through the data exchange format that both ADAMS and UG NX support. Then, the simulation models of the wire ropes are created as a lot of discrete rigid cylinders and flexible connections in ADAMS by the macro commands. Meanwhile, simplify the rotating platform, and determine the mass and the center of mass. Last, add the pair constraint to the model, besides, write kinematic parameters of the hoist,push and rotating mechanism in the form of STEP function, and determine the drive of the corresponding mechanism.3. Determine the external loads of the working implementThe paper had made analysis of the working device that withstand the external load conditions, and calculated hoist force hoist torque, push force, rotary torque, digging resistance, materials gravity and other external loads respectively, next, added the load to the corresponding components according to performance character of the physical prototype. So the virtual prototype model of the mining excavator had been created.4. Dynamic simulation and analysisDo the dynamic simulation of the working device's virtual prototype model in accordance with the various typical operating conditions, with the Simulation results, the actual digging trajectory of bucket was got, by comparing the ideal digging trajectory, the accuracy of the simulation model was verified. From the simulation results, we knew that the installation error of the reel and the rotary acceleration had the direct influence on the axial force of the reel; when there was a gap in the reel and the end block, the extreme axial force of the reel had a more substantial increase. In addition, from the simulation results, we concluded that whether the installation location was accurate or not, both installation error and eccentricity effect of the material within the bucket had little influence on the axial force of the reel. The simulation results had obtained the extreme axial force of the reel under various working conditions, the results show that when the reel tend to the right of mining excavators and the reel was not blocked tightly, the axial force of the reel would be 4 times more than the normal extreme value, and multiple contact-impact between the reel and the block would occur.5. The finite element analysis of hoisting mechanismUsing finite element method, the reel and the reel shaft ware analyzed, and the contact analysis of the reel and the reel shaft was carried out too. With the FE model, the distribution graphs of the von mises stress and the displacement vector sum of the reel and the shaft are obtained. Verified that the maximum equivalent stresses of the reel and the shaft are lower than the strength limit of the material, and the parts meet the required strength.The paper had made kinematics analysis of mining excavator's working device, and the dynamics simulation model of the hoist mechanism was created by integrating UG NX and MSC ADAMS. In addition, the paper had analyzed and calculated the external load of the working device respectively, and made the dynamic simulation respectively under different conditions such as normal conditions, material eccentric, reel's installation error, increasing the rotation speed, digging bucket encountering the obstacles and so on, reflecting the actual characteristics of the hoist mechanism accurately, and the kinetic parameters of the hoist mechanism are obtained. The paper have a positive effect on forecasting performance of the hoist mechanism, shortening the product's developing cycle, reducing product's developing costs, at the same time, the paper also have reference value on optimal design and retrofit design of the hoist mechanism.