[雙語翻譯]齒輪設(shè)計(jì)外文翻譯--用模擬和經(jīng)驗(yàn)數(shù)據(jù)設(shè)計(jì)滾齒工藝（英文）

1、Available online at www.sciencedirect.com2212-8271 © 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Se

2、lection and peer-review under responsibility of the International Scientific Committee of “9th CIRP ICME Conference” doi: 10.1016/j.procir.2015.06.059 Procedia CIRP 33 ( 2015 ) 484 – 489 ScienceDirect9th CIRP Conf

3、erence on Intelligent Computation in Manufacturing Engineering - CIRP ICME '14 Design of Gear Hobbing Processes Using Simulations and Empirical Data C. Brechera, M. Brumma, M. Krömera* aLaboratory for Machine To

4、ols and Production Engineering, Steinbachstraße 19, 52074 Aachen, Germany * Corresponding author. Tel.: +49-241-80-28295; fax: +49-241-80-22293. E-mail address: m.kroemer@wzl.rwth-aachen.de Abstract Gear Hobbing is

5、 one of the most productive manufacturing processes for pre-machining cylindrical gears. The process design as well as the tool selection is often based on experience or is limited to an iterative procedure. Existing me

6、thods for process and tool design are limited regarding the size of the gears and the process parameters. The objective presented in this paper is to support the process design by suggesting process parameters. To achie

7、ve this goal, a simulation for continuous gear hobbing was developed. By calculating planar intersections of transverse sections of both gear and tool, the generated chip geometries are determined. Due to the general a

8、pproach of positioning tool and workpiece in the program, all continuous processes with defined cutting edges can be simulated. The generated chip geometries are analyzed and characteristic values for each position of t

9、he tool are defined. Beside the chip geometries, other parameters such as working areas and the length of axis movements are calculated too. Since the simulation process is time-consuming, it is not possible to calculat

10、e each hobbing process for different designs. Also, the simulation program cannot be implemented into the machine control due to the needed computing capacity. Thus, a large amount of hobbing processes with varying gea

11、r geometries as well as different tools with the corresponding profiles are calculated in advance. By the use of regression analysis, the results of these variations are transferred to approximation formulas afterwards,

12、 which are easy to calculate and to implement into other software products. To support the tool and process design, existing hobbing processes will be simulated with the help of the developed manufacturing simulation a

13、nd the results will be stored in a database. By comparing the results of the approximation formulas with the values in the database, it is possible to evaluate a given process. © 2014 The Authors. Published by Else

14、vier B.V. Peer-review under responsibility of the International Scientific Committee of “9th CIRP ICME Conference“. Keywords: Machining; Gear; Hobbing; Process; Design; Expert System; Simulation 1. Introduction For desi

15、gning gear hobbing processes, certain values are necessary that can be compared and determined unambiguously. An established value for hobbing is the maximum chip thickness. Determining the chip thickness can b

16、e conducted according to different methods and formulas. A common and industrially as well as scientifically established way is the approximation formula for the maximum chip thickness according to HOFFMEISTER [18]. T

17、he approximation formula represents a simplified calculation that is based on empirical studies up to the module of mn = 4 mm. Investigations have shown that for gears of larger modules, the results according to HOFF

18、MEISTER deviate from the actual chip thickness and underrate them [10]. To define a reliable process design of large module gears, a dependable method for calculating the maximally occurring chip thickness in a proces

19、s is necessary. For this purpose, a new formula for calculating the maximum chip thickness up to modules of mn = 30 mm will be created. In order to achieve this objective, a variation model will be set up. This allows

20、 determining approximation functions for different characteristic values by means of results of a penetration calculation and a regression analysis. With the help of this method, subsequently a function for calcu

21、lating the maximum chip thickness for gear hobbing can be developed. 2. State of the Art For turning or milling processes with defined cutting edges, the process design and the cutting parameters are most likely speci

22、fied based on empirical knowledge, structured in © 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Sele

23、ction and peer-review under responsibility of the International Scientific Committee of “9th CIRP ICME Conference”486 C. Brecher et al. / Procedia CIRP 33 ( 2015 ) 484 – 489 as well as the tool data and its prof

24、ile geometry. With the given axial feed, a penetration calculation is executed and the undeformed chip geometries occurring in the hobbing process are determined. Afterwards, these geometries are analyzed and charact

25、eristic values such as the maximum and average chip thickness hcu,max and hcu,av, the specific chip volume V? and the maximum and average cutting length lmax and lav are calculated. The values are then displayed along

26、 the unrolled cutting edge as well as maximum and average values for the whole process. Besides these values, SPARTAPRO is capable of calculating the cutting forces of the hobbing process and the profitability. Becau

27、se HOFFMEISTER only used gears with a module mn < 4 mm, it is questionable to use the approximation formula and transferring it to large gears up to module mn = 30 mm. Thus, a comparison of the maximum chip thickne

28、ss according to HOFFMEISTER and SPARTAPRO was conducted [8]. As it is shown in Fig. 3, the results of these two methods differ widely with increasing modules. The simulation results are constantly higher than the resu

29、lts by HOFFMEISTER and at some parts the difference of the calculated and simulated chip thickness is 55%. This shows that the approximation formula according to HOFFMEISTER underestimates the tool load for large mod

30、ule gears and therefore is not the best option to use in a process design. © WZL Fig. 3. Comparison of approximate formula and simulation according to different modules [8] 3. Research objective The state of the a

31、rt shows the need for an approximation formula for the maximum chip thickness in gear hobbing which can be used for large module gears. So far, the process parameters for industrial application of the gear hobbing pr

32、ocess are chosen based on experience. By developing formulas for calculating the chip thicknesses, it is possible to create a database for tool and workpiece materials with the corresponding process parameters to supp

33、ort the process and tool design. The objective of this paper is to illustrate a method determining approximation formulas for characteristic values. This method will be afterwards used to generate an approximation fo

34、rmula for the maximum chip thickness. 4. Designing a Variant Calculation The chip formation in gear hobbing processes depends on a large amount of influencing factors. Fig. 4 shows these influences categorized into wo

35、rkpiece, the tool and the process. The highlighted geometrical influences can be considered in the described penetration calculation SPARTAPRO. The bold factors in Fig. 4 influence the chip thicknesses in the ho

36、bbing process directly and are subsequently discussed in detail. © WZL Fig. 4. Factors influencing the chip formation For analyzing the maxima for different characteristic values, the gear width is often of little

37、 interest. This is because in the run-in and the overrun of the tool chip thicknesses, cutting lengths and other values increase respectively decrease. In the full-cut section of the workpiece, the characteristic val

38、ues are nearly constant and have the highest values. To examine the influence of the pressure angle, preliminary investigations on the profile addendum and the generating addendum modification were preformed in advan

39、ce. While the cutting depth was kept constant, in each simulation the profile angle was varied between αn = 10°, αn = 20° and αn = 30°. It shows that this modification has no effect on the resulting max

40、imum chip thickness. Furthermore, the addendum of the tool profile was also changed in three steps. This change leads to a varying tooth width of the gear, but also has no effect on the maximum chip thickness. Becaus

41、e the generating addendum modification factor also changes by varying the addendum height, this factor has no effect on the maximum chip thickness as well. 5. Developing of Functions describing Characteristic Values

42、 After gear width, pressure angle and the addendum modification could be excluded, as they have no effect on the chip thickness, the parameters listed in Table 1. are varied throughout the specified range. For each p

43、arameter up to seven incremental steps are used. Furthermore, the process is simulated for climb as well as conventional cutting. A design of experiments (DOE) method is used to reduce the number of Workpiece: Module

44、mn: 1 - 30 mm Number of teeth z2: 35 Pressure angle α2: 20°Helix angle β2: 0°Diameter da2: (z2 + 2)?mnTool: Basic rack acc. DIN 3972 IV Diameter da0: (1.2?mn + 3.5)?niNumber of threads z0: 1, right Number of ga

45、ps ni: 10Process: Axial feed fa: 2.0 mm Plunging depth T: haP0 + mnC limb processModule mn [mm]max. Chip thickness hcu,max [mm]00.51.0S PAR TAproHoffmeister5 10 15 20 25 30Influence of the module on the chip thicknessChi

46、p formationGeometrical InfluenceToolTool radius ra0Number of gaps ni0Number of threads z0Lead angle ?0Protuberance PrP0Tip radius σa0Pressure angle αP0G ap angle ?N C learance angle α R ake angle ?Manufacturing tolerance

47、sTypeMaterialProcessFeed faPlunging depth TCutting process ? C limb / conventional cutting? Identical / opposite lead orientation of part and toolS hift strategy sH C utting velocity vcMachine / settingC ooling agentE