Research On Screw Thread Tightening Torque Control Technology

Screw thread connection is a very important connected mode in the joint task of Aero-engine's parts and components,and its quality directly affects the assembly quality and overall operation performance of the engine.Screw thread automatic tightening equipment is a device which integrates screw thread tightening technology and automatic control technology to realize screw thread's automatic connection.And it has some advantages about reliable connection,adaptability to complex connection assembly process and high working efficiency.Therefore,it has great application prospects in screw thread assembly of aero-engine.Due to the limitation of narrow space of engine chamber,poor screw thread connection technology and high precision of tightening torque control,the high stability and high precision tightening torque control of Screw thread automatic tightening equipment become the main difficulties;moreover,high precision tightening torque control of screw thread automatic tightening equipment can reduce the dispersion of pre-tightening force,and ensures the connecting quality of the engine.Therefore,it has a great engineering significance to study the torque control of screw thread automatic tightening equipment.This paper is aiming at the tightening torque control of aero-engine's screw thread automatic tightening equipment,establishes the relationship model between tightening torque and tightening angle in the process of screw thread connection,designs the mechanical structure of screw thread automatic tightening equipment,studies the control effect of fuzzy-PID control method on the accuracy of screw thread automatic tightening equipment's tightening torque control,and completes the experimental verification and analysis of tightening torque control through experimental system.The main research work of this paper is as follows:(1)Introduces the background and significance of this research,analyses the status and development trend about the screw thread automatic tightening equipment,and introduces the main research content and chapter arrangement of this paper.(2)Based on the analysis of screw thread connection process and pre-tightening force,the relationship model between tightening torque and tightening angle is established,and determines the target tightening torque and tightening angle in each stage of screw thread connection process,which lays a theoretical foundation for tightening moment control.(3)Based on the analysis of technical requirements and engineering process,designs the mechanical structure of screw thread automatic tightening equipment,the tightening mechanism,which is the main structure of screw thread automatic tightening equipment,is described in detail,and analyze the static characteristics of its main loaded parts.(4)Aiming at the problem of tightening torque control of screw thread automatic tightening equipment,designs the speed running curve of tightening mechanism in the process of screw thread connection,the dynamic control model of motor and driving mechanism of tightening mechanism is established,and study the tightening torque control based on fuzzy-PID control method and analyze the feasibility of this control method through simulation analysis.The results show that the tightening mechanism based on fuzzy-PID control has the advantages about fast response speed and high control accuracy of tightening torque.(5)Set up the experimental system and carry out the experimental analysis of the tightening torque control of the screw thread automatic tightening equipment,collects the tightening torque data of the tightening mechanism under different speed responses,analyses the data and proves that the fuzzy-PID control strategy can meet the control requirements of the accuracy of the tightening mechanism;At the same time,analyses the necessity of tightening speed curve planning of the tightening mechanism in the process of screw thread connection...