文献翻译用PLC模块控制3轴数控铣床制造加工螺旋锥齿轮.docx

1、文献翻译用PLC模块控制3轴数控铣床制造加工螺旋锥齿轮外文资料翻译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 .KarimianAbstractCNC machining nowadays makes more use of “Mechatronics” increasingly. Combining numerical control w

2、ith 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 motions for the cutting of spiral bevel gears. In this paper, we attempt to manufacture the spiral bevel gear using

3、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 interfaced with an indexing work head. This research consists of (a) geometric modeling of the spiral bevel gear, (b) si

4、mulating 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 milling machine were made to discover the validity of the presented method. The results demonstrate that invented

5、 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, it is an economical method in manufacturing of SBGs.Keywords: Gear manufacturing. Spiral bevel gear. CAD/CAM/CAE.

6、 CNC. PLC. AC motor. Inverter. Proximity sensors. Photoelectric sensors. Rotary encoder1 IntroductionGears are important and precision mechanisms for in dustrial machinery as a means for mechanical power or motion transmission between parallel, intersecting and nonintersecting cross-axis shafts. Alt

7、hough 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 machines and processes that have been developed for producing gears are among the most existing ingenious ones. Whethe

8、r produced in large or small quantities, in cell, or job shop batches, the sequence of processes for gear manufacturing requires four sets of operations 1:1. Blanking2. Gear cutting3. Heat treatment4. GrindingDepending on their type and application or required strength and resistance, gears are manu

9、factured by casting, extruding, forging, powder metallurgy, plastic molding, gear rolling, and machining. Among these processes, machining is more frequently used for high-precise gears 2. Among the various types of gears, the spiral bevel gears (SBG) are the most complex type and are used to transm

10、it 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-toothed varieties lies in the fact that more teeth are in contact at the same time because of the curve-shaped contour o

11、f the teeth and so a smoother meshing action between the mating pair is ensured 3. The design and manufacturing of spiral bevel gears is still a hot topic of research that is vita for application of such gears in helicopter transmissions, motorcycle gears, reducers, and in other branches of industry

12、. 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 manufacturing machine tools are used in industrial practice. This may be why literature on gear manufacturing is sparse in th

13、e 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 inherently different from the industrial CNC milling machine, as the former is designed for a special type of cut

14、ter.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 4-8. Tsai and Chin 4 presented a mathematical surface model for bevel gears (straight and SBGs) based on basic gearing kinema

15、tics and involutes geometry along the tangent planes. Later, this method was compared with another model based on exact spherical involutes curves by Al-Dacca et al 5. Shunmugan et al. 6, 7 presented a different model, and its accuracy (compared with the spiral bevel gear manufactured by special mac

16、hine tools) was verified in terms of nominal deviation.For crown gears, a few results are available. Litvin and Kim 8 suggested a generation method for an involute curve from a modified base circle for a spur gear. Umeyama 9 designed a standard profile at the pitch circle and a modified profile at t

17、he top/bottom face gear with a determination of the modification value for transmission error of helical gear. Tamura et al. 10, 11 studied a point contact model for a bevel gear using a flat surface tooth. These studies are concerned with the generation of the tooth profile for special gear machine

18、s, such as gear hobbing and shaping machines, which are specially designed for manufacturing gears. Suh et al. 12 investigated the possibility of a sculptured surface-machining method for the manufacture of spiral bevel gears and verified the possibility by presenting tool-path generation using a fo

19、ur-axis CNC milling machine interfaced with a rotary-tilt table. A model-based inspection method for the spiral bevel gears was also presented 13.In this paper, we attempt to present a new manufacturing procedure of SBGs by using a three-axis milling machine interfaced with a PLC module which operat

20、es 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 respects: (1) the conventional method requires a large investment for obtaining various k

21、inds 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-axis CNC milling machine; (3) this method is more economical than using the special mac

22、hine 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 have been engaged in calculating complicated mathematical equations and designing geom

23、etric 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 mechatronics tools and a three-axis CNC milling machine are being used simultaneously in manufacturing a special gear and

24、 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 required for defining the geometry. Figure 1 shows module, spiral angle, and number

25、 of teeth of gear. Table 1 summarizes these parameters including relationships among parameters for the gear which has been manufactured in our test. To calculate these parameters, we have used “drive component development software” called GearTrax.The design of spiral bevel gear requires high-accur

26、acy mathematical calculations, and the generation of such gear drives requires not only high-quality equipment and 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 d

27、esign (depending on geometric parameters of the gear drive and generating tools) to guarantee the required quality 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 gear

28、s having very high accuracy. Form milling is one of the most common machining processes used to manufacture any types of gears 14. 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 si

29、zes for each diametral pitch and will cut gears having the number of teeth indicated in standard tables.Gleason works 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 c

30、omplementary generating crown gears 15. The tooth surfaces of the generating crown gears are kinematically formed by the traces of the cutting edges of the tool blades as shown in Fig. 2.As it is shown in Eq. 1, velocity ratio of face hobbing process depends on tooth number of tool and generating ge

31、ar: （1）Where, and denote the angular velocities of the tool and generating gear; and 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 by Eqs. 2 and 3: where is the machine radial sett

32、ing.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 mating 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 (Fig. 3).To man