Research On Key Technologies Of Direct-Drive Servo NC Turret Tool Post

NC turret tool post, as the key part of NC lathe, its performance has directly influenced machining efficiency and accuracy.With the development of servo-motor and its drive-technology, the turret driven by servo-motor comes true. By taking the place of the pre-indexing device and transmitter devices, Servo-motor greatly enhances the performance of the turret tool post by simplifying the structure, improving the reliability of the turret and shortening the time of tool exchanging. The bad performance of servo-motor at low speed impedes the development of the servo turret, so we must use multi-stage gear reducer to obtain enough torque. Direct-drive means the equipments are directly driven by the motor, which reduces the middle transmission devices and realizes the zero transmission. Direct-Drive-Motor is a new product of high-technology with smaller moment of inertia and better response, compared with conventional servo motor, it can output high torque at low speed and directly drive the low speed equipment, which has a high application value. In order to simplify the turret’s structure and improve the overall performance, we apply the technology to NC turret to develop a kind of high performance direct-drive servo NC turret. The main contents are as follows:Firstly, study the situation of the CNC turret tool post, study the structure of some CNC turret tool post at home and abroad, analyze the characteristic、applications、advantages and disadvantages of various structure, analyze the characteristics of direct-drive servomotor and the feasibility to drive the turret.Secondly, learn from the structure of CNC turret tool post at home and abroad, according to the direct-drive servomotor’s own structure and characteristics, design a horizontal CNC turret tool post, including detent mechanism, control devices, sealing device etc.The third, design the loosen and locking mechanisms of direct-drive CNC turret tool post, mainly design the hydraulic cylinder and calculate the parameters relevant with the hydraulic system of direct-drive CNC turret tool post, calculate the clamp force, chose suitable motorized spindle type. The fourth, study indexing techniques of direct-drive CNC turret tool post, study tool identification methods and tool selection approach of CNC turret tool post and analyze the two-way inversion and nearby tool-changing theory, workout the tool-changing flowchart.Study the control theory of the AC motor and optimize the parameters.The fifth, establish a direct-drive CNC turret tool post3D model with PRO/E, then import it into ADAMS, observe the direct-drive CNC turret toolpost movement process, detecte motion curves of moving parts. In dynamics simulation, imitate the actual cutting process stress, measure the axial force of terminal gear disk in order to test and verify the clamp force.