1、PLC模块控制回转工作台在三轴数控铣床铣削螺旋伞齿轮中的应用外文文献翻译中英文翻译外文翻译附录二Use of PLC module to control a rotary table to cut spiral bevel gear with three-axis CNC millingS. Mohsen Safavi & S. Saeed Mirian & Reza Abedinzadeh & Mehdi KarimianReceived: 25 November 2008 / Accepted: 23 November 2009 # Springer-Verlag London Limit
2、ed 2009Abstract CNC machining nowadays makes more use of Mechatronics increasingly. Combining numerical control with mechanic, electric, and data processing systems can lead to new methods of production. In recent years, the development of CNC has made it possible to perform nonlinear correction mot
3、ions for the cutting of spiral bevel gears. In this paper, we attempt to manufacture the spiral bevel gear using a three-axis CNC milling machine interfaced with an additional PLC module based on traditional discontinuous multi-cutting method accomplished by using a universal milling machine interfa
4、ced with an indexing work head. This research consists of (a) geometric modeling of the spiral bevel gear, (b) simulating the traditional and our new nontraditional method using a CAD/CAE system, (c) process planning for CNC machining and PLC Programming, (d) experimental cuts with a three-axis CNC
5、milling machine were made to discover the validity of the presented method. The results demonstrate that invented experimental cutting method of SBGs not only is less expensive than advanced CNC machining but also produces gears in a shorter time in comparison with the traditional cutting. Thereby,
6、it is an economical method in manufacturing of SBGs.Keywords：Gear manufacturing . Spiral bevel gear .CAD/CAM/CAE . CNC . PLC . AC motor . Inverter .Proximity sensors . Photoelectric sensors . Rotary encoder1 IntroductionGears are important and precision mechanisms for industrial machinery as a means
7、 for mechanical power or motion transmission between parallel, intersecting and nonintersecting cross-axis shafts. Although hidden from sight, gears are one of the most important mechanical elements in our civilization. They operate at almost unlimited speeds under a wide variety of conditions. The
8、machines and processes that have been developed for producing gears are among the most existing ingenious ones. Whether produced in large or small quantities, in cell, or job shop batches, the sequence of processes for gear manufacturing requires four sets of operations: 1. Blanking2. Gear cutting3.
9、 Heat treatment4. GrindingDepending on their type and application or required strength and resistance, gears are manufactured by casting, extruding, forging, powder metallurgy, plastic molding, gear rolling, and machining. Among these processes, machining is more frequently used for high-precise gea
10、rs. Among the various types of gears, the spiral bevel gears (SBG) are the most complex type and are used to transmit the rotational motion between angularly crossed shafts.SBGs have teeth curved longitudinally along the length of the teeth. The main advantage of these gears over the straight-toothe
11、d varieties lies in the fact that more teeth are in contact at the same time because of the curve-shaped contour of the teeth and so a smoother meshing action between the mating pair is ensured. The design and manufacturing of spiral bevel gears is still a hot topic of research that is vital for app
12、lication of such gears in helicopter transmissions, motorcycle gears, reducers, and in other branches of industry. As far as manufacturing is concerned, the gears are machined by a special type of machine tools, such as gear hobbing and shaping machines. Recently, special CNC-based gear manufacturin
13、g machine tools are used in industrial practice. This may be why literature on gear manufacturing is sparse in the open research domain. Recently, CNC-based gear manufacturing machine tools have been developed and increasingly used in industrial practice. However, their kinematic structure is still
14、inherently different from the industrial CNC milling machine, as the former is designed for a special type of cutter.Previous studies on gears have been mainly concerned with the design and analysis of gears. The geometric characteristics and design parameters of gears have been studied. Tsai and Ch
15、in presented a mathematical surface model for bevel gears (straight and SBGs) based on basic gearing kinematcis and involute geometry along the tangent planes. Later, this method was compared with another model based on exact spherical involute curves by Al-daccak et al. Shunmugan et al. presented a
16、 different model, and its accuracy (compared with the spiral bevel gear manufactured by special machine tools) was verified in terms of nominal deviation. For crown gears, a few results are available. Litvin and Kim suggested a generation method for an involute curve from a modified base circle for
17、a spur gear. Umeyama designed a standard profile at the pitch circle and a modified profile at the top/bottom face gear with a determination of the modification value for transmission error of helical gear. Tamura et al. studied a point contact model for a bevel gear using a flat surface tooth. Thes
18、e studies are concerned with the generation of the tooth profile for special gear machines, such as gear hobbing and shaping machines, which are specially designed for manufacturing gears. Suh et al. investigated the possibility of a sculptured surface-machining method for the manufacture of spiral
19、bevel gears and verified the possibility by presenting tool-path generation using a four-axis CNC milling machine interfaced with a rotary-tilt table. A model-based inspection method for the spiral bevel gears was also presented. In this paper, we attempt to present a new manufacturing procedure of
20、SBGs by using a three-axis milling machine interfaced with a PLC module which operates as an indexing table. In terms of production rate, it is obvious that this method will be lower than that of the special machine tool. Other than production rate, this method is advantageous in the following respe
21、cts: (1) the conventional method requires a large investment for obtaining various kinds of special machinery and cutters dedicated to a very limited class of gears in terms of gear type, size, and geometry; (2) by this method, various types of gears can be manufactured with the industrial three-axi
22、s CNC milling machine; (3) this method is more economical than using the special machine tool. One of the main points which separate our work from previous ones is developing an automatic computer model in order to simulate the process entirely and obtain machining parameter. All previous studies ha
23、ve been engaged in calculating complicated mathematical equations and designing geometric models. In view of the above, special attention is given to experimental tests rather than presenting geometrical or mathematical model of SBGs. This is the first time that mechatronic tools and a three-axis CN
24、C milling machine are being used simultaneously in manufacturing a special gear and even a mechanical element.2 Geometric specifications of the spiral bevel gearsMost of the time, the geometric parameters of a gear are provided with an engineering drawing. Some parameters (principal parameters) are
25、required for defining the geometry. To calculate these parameters, we have used “drive component development software” called GearTrax. The design of spiral bevel gear requires high-accuracy mathematical calculations, and the generation of such gear drives requires not only high-quality equipment an
26、d tools for manufacturing of such gear drives but also the development of the proper machine-tool settings. Such settings are not standardized but have to be determined for each case of design (depending on geometric parameters of the gear drive and generating tools) to guarantee the required qualit
27、y of the gear drives.3 Manufacturing the SBGAs it was discussed in the introduction, by machining, all types of gears can be made in all sizes, and machining is still unsurpassed for gears having very high accuracy. Form milling is one of the most common machining processes used to manufacture any t
28、ypes of gears. The cutter has the same form as the space between adjacent teeth. Standard cutters usually are employed in form-cutting gears. In the USA, these cutters come in eight sizes for each diametral pitch and will cut gears having the number of teeth indicated in standard tables. Gleason wor
29、ks used the face hobbing process that is based on the generalized concept of bevel gear generation in which the mating gear and pinion can be considered respectively, generated by the complementary generating crown gears. As it is shown in Eq. 1, velocity ratio of face hobbing process depends on too
30、th number of tool and generating gear: （1）where, wt and wc denote the angular velocities of the tool and generating gear; Nt and Nc denote the number of the blade groups and the tooth number of the generating gear. The radii of the rolling circles of the generating gear and the tool are determined b
31、y Eqs. 2 and 3: （2） （3）where s is the machine radial setting.The generating crown gear can be considered as a special case of a bevel gear with 90 pitch angle. Therefore, a generic term “generating gear” is used. The concept of complementary generating crown gear is considered when the generated mat
32、ing tooth surfaces of the pinion and the gear are conjugate. In practice, in order to introduce mismatch of the mating tooth surfaces, the generating gears for the pinion and the gear may not be complementarily identical. The rotation of the generating gear is represented by the rotation of the cradle on a hypoid gear generator. To manufacture the SBGs with the three-axis CNC milling machine, we first test the process by developing a CAD/CAM system composed of geometric modeling and graphic simulation modules. The commercial software Sol
