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1、Research on Open-die Cold Extrusion Technology of the Electromotor Shaft Shoulder Fillet Shuang-jie Zhang, Ying Gao, FumingZeng, lun Li College of Material Science and Engineering Hebei University of Science and Technology Shijiazhuang, Hebei, China shuangi- Abstract-Using open-die cold extrusion te

2、chnology instead of traditional cutting to form the electromotor shaft shoulder fillet is presented. In comparison with cutting methods used in industrial application, open-die cold extrusion has many advantages such as minimum material waste, high dimensional accuracy, reduction or complete elimina

3、tion of machining, good surface finish, better mechanical properties of products than those of the original material due to favorable grain flow. The analysis on the two forming for the electromotor shaft shoulder, including one-step approach and two-step approach, is carried out. Numerical simulati

4、on and experimental investigation on it is performed and the different application ranges of the two methods are achieved. Keywords-open-die cold extrusion; electromotor shaft shoulder; numerical simulation; experimenflll investigation; one-step approach; two-step approach component I. INTRODUCTION

5、Open-die cold extrusion is an advanced forming technology which can not only reduce the machining time and material waste but can also improve the properties of the productsl and is suitable for forming of low-carbon steel, low-carbon alloy structure steel and medium carbon steel in the appropriate

6、shape. It is primarily available for axial symmetry parts in the shape and easy to realize automated production. It is an advanced manufacturing process for electro motor shaft production in high efficiency and in a large batch. In this paper, using open-die cold extrusion technology instead of trad

7、itional cutting to form the electromotor shaft shoulder fillet was presented. II. DESCRIPTION OF OPEN-DIE COLD EXTRUSION FORMING Fig. 1 shows the motor shaft open-die cold extrusion diagram. Here DO, Df is outer diameter of the initial blank and extruded blank respectively, 2a is a die cone angle, R

8、I (R2), b is die transition comer and working zone length. Billet 2 is gradually passed through the die 3 by pressure P imposed on punch using extrusion equipment so that a certain size and cross-section shape of pieces is achieved 2. In this paper the deformation is measured in terms of changes in

9、outer diameter before and after deformation 3-5, that is (D -D ) 10= 0 J xlOO% Do J -.t-.J_I_ I I L_Dr J Figure I. Sketch of the electromotor by open-die cold extrusion III. Two METHODS OF OPEN-DIE COLD EXTRUSION FORMING FOR ELECTROMOTOR SHAFT (1) Open-die cold extrusion of electro motor shaft inclu

10、des diameter necking and shoulders comer extruding, which are achieved by two approaches as following 1) To perform direct extrusion of round rod billet using round comer die so that the two formings are implemented at the same time, which is known as one-step approach shown in Fig.2. 2) Extrusion o

11、f the two parts is divided into two steps, extruding billet into cone-shaped stepped shaft first and then extruding it into an electromotor shaft with rounded shoulder transition, known as two-step approach shown in Fig.3. The analysis on the performance of two methods is carried out respectively in

12、 this investigation. 978-1-4244-6349-7/10/$26.00 201 0 IEEE Vl-702 die Figure 2. Sketch of one-step extrusion Figure 3. Sketch of two-step extrusion A. Results of one-step formability simulation and experiment 1) Material properties and process parameters applied in simulation. The parameters applie

13、d in simulation are involved in material 45 steel, friction coefficient 0.08 between the billet and the die, friction coefficient 0.12 between the billet and the punch and extrusion temperature 200e 2) Results of simulation and experiment. A large number of numerical and experimental results show th

14、at one-step open-die cold extrusion process for electro motor shaft would be successful only on the condition of deformation with lO. Varying degrees of collapse phenomenon emerges under the combination of other technical parameters. Tab.l gives the value of 0 under different combinations of process

15、 parameters as well as in the same punch displacement (the local accumulating height of the top of deforming paragraph for the blank, mm). For other given parameters, the greater the deformation is, the smaller the fillet, the greater the value of 0 6. FigA and Fig.5 illustrate the numerical results

16、 and experimental results. It shows the die fillet of 10.Omm and two different deformation degrees of 3% and 5% in FigA. Deformation degree increses, metal flows into the die fillet difficultly and metal accumulation appears obviously as shown in FigA (b). From the Fig.5 it can be seen that metal ac

17、cumulates markedly while deformation degree is equal to 3% and 5% and die fillet radius is less than or equal to lOmm. According to the numerical and experimental results, it is found that one-step open-die cold extrusion process for motor shaft would be implemented successfully only in a small defo

18、rmation degree ( 3% ), while satisfied comer cannot be attained. Additional working procedure is required to remove or cut accumulated metals. Thus the scope for using this method is narrow, which could not be applied in a larger degree of deformation of the extrusion. TABLE I. l) UNDER THE COMBINAT

19、ION OF DIFFERENT PROCESS PARAMETERS(MM) 4.0 6.0 8.0 10.0 12.0 3% 1.42 0.38 0.2 0.04 0 5% 0.7 0.4 0.1 0.06 10% Upsetting 1.64 15% Upsetting Upsetting a) Figure 4. Numercal results: a) e =3% , Rb=IO.O; b) e =10%, Rb=IO.O Figure 5. Experimental results of electromotor shaft by one-stepextrusion: a) e =

20、3%, Rb=4.0; b) e =5%, Rb=4.0; c) e =3%, Rb=lO.O B. Results of two-step formability simulation and experiment The two-step extrusion process is shown in Fig.3. In the simulation, the formability of two-step extrusion could be analyzed quantitatively analysis by changing the deformation degree , semi-

21、angle of cone-angle die a and the forming comer of round die Rb. Fig.6 shows the simulation results of the necking extrusion. Necking results is good as deformation degree is equal to 15% or 20% and the angle is 10 . Fig.7 gives the deformation of simulation results of the fillet extrusion, which sh

22、ows the metal along the die fillet flow into die with a large resistance as the deformation degrees is 10%, the angle is 10 and the die Vl-703 2010 2nd International Conference on Computer Engineering and Technology Volume 1 fillet radius si 4mm. Metal accumulatation appears in the die fillet region

23、. When the fillet increases to 15mm the forming result is good due to the easy flow into the die. Fig.8 shows the experimental results. b) + Figure 6. Simulation results of two-stage extrusion process: a) E =IS%, a =100 ; b) E =20%, a =10 a) b) Figure 7. Simulation results of two-stage extrusion pro

24、cess: a) E =10%, a =100 , Rb=4; b) E =IO%,a =100 ,Rb=IS Figure 8. Experimentao results of electromotor by two-step extrusion process IV. CONCLUSIONS This work gives manufacturing methods for motor shaft. Two Conclusions are drawn from the above investigation. I) The utilization scope and limitation

25、of one-step open die cold extrusion technology for motor shaft is pointed out by simulation and experiment. It is demonstrated that the process is not suitable for motor shaft production under the condition of 3% and Rb I Omm. 2) Through numerical and experimental research methods, it is confirmed t

26、hat the two-step open-die cold extrusion technology for motor shaft is feasible. REFERENCES I Li Jun, Research on Open-die Cold Extrusion Formings Modeling and Its Technological Parameters Application, Tianjin University, 1997. (IN CHINESE) 2 Zeng Fuming, Research on Open-die Cold Extrusion Technique and Its Key-parameters of Electromotor Shaft, Hebei University of Science and Technol