Study On Automatic Adjustment Device For Fixed Torque Bolt

Thread connection is the most widely used connection mode in machinery industry, because it has a number of advantages:when tighten the screw it can produce large axial force; it can easily achieve self-locking; small size; it can be easily manufactured and maintain high accuracy; it can be mass-produced through standardization, thus, cost low and has interchangeable.In order to increase the rigidity, compactness and capacity of the thread connection, and prevent the bolt from sliding, which is affected by lateral loads, most of thread connection will be tightening in the assembly. Generally through tightening torque to control the preload of bolt, but this method produces large error, and can not be precise controlled. With the development of science and technology, the control requirements of bolt preload have become more and more sophisticated, which generated a lot of new bolts, fixed torque bolt is the one among them, it has the function of loose monitoring, and rated torque can be achieved precise control.This paper mainly designs a set of automatic adjustment device for fixed torque bolt, by which we fix the fixed torque bolt, accurately control the preload of bolt, and ensure the relative error is less than 5%. This paper mainly includes the following content:(1) Determine the scheme of each part of the automatic adjustment device for fixed torque bolt, including bolts stretching part, driving part and control part, and then set the overall scheme. (2) Calculation and type selecting for each part of the automatic adjustment device for fixed torque bolt, and determine the structure of each part and finally give overall structure. (3) Design the control and drive circuit diagram, Design the control and drive circuit diagram, and compile corresponding control procedures by the programming software which called STEP 7 Micro-WIN32. (4) Simulation analysis to each factor which affects the control precision of automatic adjustment device for fixed torque bolt, and adopt corresponding measures to make a relative error less than 5%.