| Nowdays the main transmission mode of drilling machine is mechanical drive and electric drive. Mechanical drive is usually achieved through the gearbox speed transmission which has high output torque and high transfer efficiency, but the structure of which is complicated and costly, big noise, not stepless speed. Electric drive works through inverter motor driving spindle movement. Although the output speed is stepless adjustment; the output torque is small, and it can only adapt to tiny holes machining. Hydraulic transmission has high output power, stepless adjustment of speed and transmission noise, etc. But there is not hydraulic transmission in the drill spindle rotational motion detection from information. Although there is hydraulic transmission in the feed motion, the drive performances have deficiencies. So it is necessary to design a hydraulic drilling machine.The paper mainly designs and studys full hydraulic drilling machine and introduces its types and characteristics. And it also analyses and studys the research status and development trends of the drilling machine. The solution of drilling machine for the main problems currently is proposed, the research direction and content is determined. And the drilling machine transmission mechanism and control system is designed; complete the design of the full hydraulic CNC drilling machine. Three-dimensional digital prototype was designed by Solid Edge three-dimensional mapping software.As vertical Drilling a design model, the spindle rotational motion and the feed motion scheme are designed and researched Based on the characteristics of vertical drilling machine.And also the spindle rotational motion mechanism, the feed movement mechanism and the lifting table mechanism are designed. The rotation of the spindle using the hydraulic motor is driven by a gear change spindle, which is a new attempt in the use of the hydraulic drive to the drill spindle drive. Feed motion is drived by using a combination of hydraulic whose structural design is innovation. After the design, calculation and component selection of the spindle rotational movement of the hydraulic control system, feed movement of the hydraulic control system, worktable elevating hydraulic control system is completed.Uses electro-hydraulic proportional valve as the control of the main valve. Spindle rotation speed control loop uses electro-hydraulic proportional valve, variable pump, variable motor to compositing Volume Throttling Speed. The spindle speed is controled by closed loop through the speed sensor which improved control accuracy. Through displacement sensors and PLC control unit, the feed speed and position of the spindle are controled by using the electro-hydraulic proportional valve to control the flow into the combination of hydraulic cylinders.The performance of the system is analysed after the system mathematical model of Servo Motor Speed-control and the valve controlled cylinder position-control are built. After determined the parameters of the control link, the system is simulated by computer. Through the integration of trial-and-error method to determine the optimal parameters for the PID, and improved the control performance of the system. |
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