The date of receipt: 2 (1) 1 - 02 1 活塞 Piston piston as the engine combustion driving force into the core components of mechanical movement, directly affects the engine and even the entire power, transmission system performance indicators. As the fuel consumption, output power and rotational speed of the engine increase, the gas pressure and inertia force of the piston are getting larger and larger, and the load on the pin hole of the piston is also increasing, so that the pin as the supporting part in the conventional structure. The problem of cracks in the upper part of the inner surface of the hole becomes very important. Due to the alternating effect of high temperature and high pressure in the engine cylinder, the ordinary cylindrical pin holes are subjected to uneven load, which is affected by thermal deformation and mechanical deformation. The inner side stress of the pin hole is the largest, and the stress concentration is easy to occur, while the outer stress is the smallest. The piston pin is bent to concentrate the load toward the inside of the pin hole; the flexible structure of the piston also tends to redistribute the load in the direction of the pin hole; the gas pressure in the pin hole of the piston causes the maximum pressure position to move from the outside to the inside, and the increase in the operating temperature affects the piston pin. The contrast with the cross-sectional radius of the pin hole causes the load to concentrate toward the vertical plane. Therefore, by changing the geometry of the pin hole, the stress concentration inside the pin hole is reduced, the mechanical load and heat load of the pin seat are equalized, the bearing capacity of the pin seat is improved, and the service life of the piston is prolonged, which has considerable economic benefits and valuable. Technical value. With the advent of the digital age, a new topic, a new type of piston shaped pinhole CNC boring technology has emerged. At present, the shape of the pin hole of the piston mainly has the following types: elliptical type, inner bell mouth type, with unloading groove type, etc., and these non-cylindrical pin holes are generally referred to as "shaped pin holes". 2 Research status is restricted by super-finishing technology, numerical control technology and industrial automation technology. The research on piston shaped pin hole processing technology is still in its infancy. At present, there are mainly the following processing schemes: 2.1 Tractor-cutting method This scheme is based on the principle that the oblique section of the cylinder is an ellipse, and the processing of the ellipse is transformed into a circle, which is excellent in processing efficiency and precision. Representative of the United States B0HAI company, they use mechanical chute feed, processing accuracy of 0.005mm. But its fatal weakness is limited to processing standard ellipse, for more and more non-standard oval holes (such as inner bell mouth The processing of the pin hole) is powerless. 2.2 Mechanical profiling machine The profiling method is realized by the profiling of the profile to control the radial feed of the file. At present, many manufacturers at home and abroad have adopted this technology to process the special-shaped pin holes of pistons. For example, KS Company of Germany adopts mechanical profiling technology to process special-shaped pin holes with an accuracy of 0.005 mm. It has the disadvantages of low transmission accuracy and poor frequency response characteristics. 2.3 Numerical Control Deformation Mast Machining Numerical Control Deformation Mast processing is the use of piezoelectric ceramics or super-large magnetostrictive rod elements to expand and contract under the condition of voltage magnetic field change. The precise control of the displacement of the mast is realized by the computer accurately controlling the change of the electric field. . The principle is to groove the mast, and then place the piezoelectric ceramic or the giant magnetostrictive rod element in an appropriate position, so that the elongation of the mast is converted into the deflection angle of the mast. The method has the advantages of simple mechanical structure, high precision, easy digital control and high frequency response, and is a development direction of modern piston design, and can be adapted to the processing of various special-shaped pin holes. The new NC boring machine successfully developed by the Institute of Automation of Guangdong University of Technology adopts a new type of deformed mast mechanism and micro-drive technology powered by piezoelectric elements, which can efficiently boring piston shaped pin holes and meet the requirements of micron precision. Technical performance indicators Both reached the international leading level. 3 System scheme design As shown in the figure, taking the inner bell-type pin hole as an example, the scheme design demonstration of the new piston special-shaped pinhole CNC boring system is carried out. 0 is the taper of the inner bell-type piston pin hole, L is the taper hole length, and A is the stroke. In the design of the inner bell mouth type piston, the spindle speed of the machine tool is set to n spindle = 3000r/min, the lead of the ball screw is L lead = 5mm, and the taper of the inclined slider is 1:100 (see 4.2). The relevant content in the design of the micro feed device) is driven by a synchronous gear belt between the ball screw and the AC servo motor. At present, the piston L=boring feed used by the Santana sedan is taken as /=0.03~1.0mm/r, then the radial feed rate of the boring tool is: n=the factory slider=1.08 L lead, so the AC servo motor is required. The speed is: when the spindle speed reaches 3X103r/min, the AC servo motor used in the micro-feed device rotates at least once every minute, and the speed is within the speed range of the AC servo motor, so the AC servo motor can respond to the spindle rotation. The requirements can be used to cut out the required inner bell-type pin holes. During the boring process, if the trajectory of the boring tool tip can accurately pass through these mesh nodes, it can slash the ideal pin hole. The task of the CNC system is here, that is, let the boring tool move along the pre-programmed trajectory in the X direction. Sx=X(0i,Z) is pre-calculated according to the drawing requirements and stored in the memory of the control computer. The corresponding data is sent during the processing. The development of the micro-feed digital control system with a response frequency of not less than 18X103Hz is the key technology of the system design. 4 system design 4.1 control model ournalElectronicPublish computer through the industrial control computer to determine the boring process in the boring tool This set of piston shaped pin hole CNC boring system uses digital technology control, the industrial control computer sends out the control signal (pulse number), drive communication The servo motor runs to drive the ball screw to drive the bevel slider to slide back and forth on the linear guide rail, which causes the deformable section of the flexible joint to deform, so that the mast can be slightly displaced in the radial direction and the required piston can be processed. The purpose of the profile pin hole. The position detection signal generated by the sensor is sent back to the industrial control n-spindle. The micro-feed device designed by the micro-feed device discards the deformation of the piezoelectric element, the magnetostrictive rod, etc. after being controlled, thereby making the mast The basic idea of ​​micro-displacement along the radial direction of the pin hole is to design a new mechanical micro-feed device from the perspective of mechanical transmission, as shown. Micro-feeding device 1. Flexible joint 2 beveled slider 3. A beveled slide of the taper of the sleeve 100 slides back and forth on the linear guide to cause the flexible joint to deform, and the mast will deviate from the axial direction by a slight angle. Thereby a micro-displacement occurs in the radial direction of the piston pin bore. The slide rail of the linear guide rail is mounted on the inclined surface slider, the slider of the linear guide rail is mounted on the flexible joint, the fixed end of the flexible joint is fixed on the hollow spindle of the machine tool, the hollow spindle of the random bed rotates, and the mast is fixed in the flexible shaft The deformable end of the joint. The other end of the ramp slider is fixed to a sleeve by a rolling bearing, and the sleeve is fixed to the nut of the ball screw. The sleeve is fixed to the machine bed by a linear bearing and can only be fed back and forth with the rotation of the ball screw. In addition, a linear bearing can be installed in the middle of the inclined slider, the linear bearing is fixed on the hollow spindle of the machine tool, and the hollow spindle of the random bed rotates to increase the stability during the transmission process. 4.3 Software design and error analysis When boring the inner bell-type pin hole, it is a certain value, so only need to calculate the x (/) value (that is, the number of transmitted pulses required by the AC servo motor N) and store it in Control the memory of the computer. According to the pulse equivalent (such as 0.01) and the total length of the piston pin hole selected by the working platform (stepper motor or position detecting component), the number of required memory cells (not more than 64k) can be calculated to store the array x according to the stroke A. , taper hole length L (10mm), bevel slider taper, ball screw lead L lead and AC servo motor thread m (1 line, incremental encoder pulse: 25 (1) pulses per revolution), calculate AC servo The number of pulses required for the motor corresponding to the Z direction of Z = 0.01 mm N. = lead = 0. The number of pulses required per revolution of the AC servo motor N: If the feed of the boring is taken as /= 1.0mm/r is the working platform - one pulse equivalent time: the time required for the AC servo motor response: up to 3000r/min, so it can fully meet the feed of the AC servo motor in response to the working platform. 5 Conclusion The piston shaped pin hole can improve the stress distribution state and prolong the service life of the piston. Therefore, it has significant practical value for high-efficiency engines and has become the main direction of the development of the international piston industry. Furthermore, the system can also be used for the machining of other workpiece shaped holes and can be extended to the application field of super finishing control. In accelerating China's industrial automation process and enterprise technology transformation, the development and research of piston shaped pin hole boring CNC system has broad application prospects and far-reaching 71994-2014 ChinaAcademicournal object-oriented complex shape tool CNC integrated system to pass on, Jin Jianxin (Information School of Huazhong University of Science and Technology, Wuhan 430074, China). The composition and principle of the information model are described in detail. 1 In the traditional tool processing, the tool has to be drawn from the design to the manual before it can be machined. For the design of complex shape tools with complicated blade edges, the drawing work of the tool will be relatively large, and there is a lot of repetitive work. CAD/CAM-bodyization simplifies tool design and accelerates tool improvement. As shown. An important issue in CAD/CAM systems for complex shape tools is the information modeling of the system. To this end, the object-oriented method is used to explore the specific implementation of the complex shape tool CNC integrated system modeling. 2 Structural analysis of complex shape tool CAD/CAM system 2.1 Requirements of complex shape tool CAD/CAM system The engineering system has the following characteristics and requirements: The system covers a wide range. It involves computer graphics, tool design, real-time control systems, CAD, CAM, CAPP and more. If you want to implement CAD and CAM-organized organic systems, you need to have a unified model throughout the system. The system has a large capacity. The system must meet the processing of most tools in the tool industry. The entire CAD/CAM system must have a tool database to manage the various tools and support the operation of the entire system. The requirements of the system are changing. Tools are constantly being introduced, and how to design and process new tools on existing systems is a consideration. The system should be adapted to the needs of modern processing. Date of receipt: 2 (1) 0-12 - meaning. It is foreseeable that in the near future, a new type of piston machining automation production line based on computer numerical control, online detection and information feedback will be promising. (Finish) Hand Gloves,Medical And Food Gloves,Disposable Sterile Gloves,Disposable Transparent Gloves BIQIAO MEDICAL TECHNOLOGY(HENAN) CO.,LTD , https://www.medical-technology.net