外文翻译-对塑料齿轮僵硬的数据分析.doc

1、Journal of Shanghai Jiao tong University (Science) ,Vo l. E210,No. 3, 2005, 303 306Article ID: 100721172 (2005) 0320303204Numerical Analysis of Plastic Gear StiffnessXIE W en2bo13 (谢文博) , I IJ IM A Kiichiroh1( 饭岛喜一郎) , LU Hao2( 陆皓)(1. School of Materials Sci.& Eng. , Shanghai Jiao tong Univ. , Shang

2、hai 200030, China;2. Fuji Xerox Co. L td. , Japan)Abstract: This paper established practical 3D gear models to study the stiffness influencing factors of a loaded gear by finite element method, such as friction parameters, material properties, and gear structures. The research shows that, in elastic

3、 deformation, gear stiffness increases when sliding friction ability of contact pair decreases ;mean while, the gear structure, especially asymmetric design in gears shaft direct ion will also decrease gear stiffness.Key words: plastic gear; stiffness; structure; friction; numerical analysisDocument

4、 code: AIntroductionGear stiffness is one of the key influencing factors on gear transmission performance. For years, overseas and native scholars carried out lots of researches on gear stiffness. Especially, in recent years, with the development of numerical method and computer techno logy, gear st

5、iffness research and prediction can be performed by numerical simulation. Up to now , the research of gear stiffness is almost about the gear meshing. The research about gear structure is relatively limited, and in most cases models were 2-D. Meanwhile, current researches mostly focus on metal gear;

6、 how ever the plastic gear which is low cost and is frequently used in light transmission process ( such as laser printer or copy machine) is seldom studied. Therefore, about plastic gear, in order to direct gear design without trial manufacture, it is necessary to establish model and predict gear s

7、tiffness of various structures. So, this paper performed finite element analysis about this point, and then verified simulation results by experiment. The tooth deform action of plastic gear includes elastic and plastic parts. The plastic deformation is small, which help s tooth contact accuracy and

8、 too thrunningin 1 . So this paper does not discuss plastic deformation, only discusses the stiffness and it s influencing factors which are based on the tooth contact deformation and tooth torsional deformation 2 .1:Simulation and Experimental ConditionsA series of gears are studied by FEM. Figure

9、1 shows the layout of gears, namely standard gear, symmetry gear and offset gear. Symmetry gear and offset gear both have two kinds of thickness, which are“thickness 2”and“thickness 4”.Gear is fixed by jigs on to shaft. A pressure of 5 kN is applied to jigs, thus gear can not rotate freely due to th

10、e friction force between gear body and jigs. A driving force of 10 50 N is applied to tooth through a hitter. The contact point between tooth and hitter is on pitch circle ( r= 33. 5 mm ). Because we only wanted to study the tooth contact deformation and tooth torsional deformation, for Simplificati

11、on, we used single tooth trapeium gear, rather than the usual involute gear.The material of gears is polyacetals. Other part s ( such as shaft, jigs, hitter) were made of steel SU S304. Because the deformation of SU S304 is much smaller than polyacetals, it is flexible rigid contact. In simulation,

12、we can define SUS304 parts as rigid bodies. When rotating angle is small, by knowing the relation of “load rotation angle”, we are able to calculate gear stiffness 3 .Meanwhile, in simulation, the movement and boundaries of rigid bodies can be simply controlled by a pilot node ( rigid node). In this

13、 paper, regarding material properties, the influences of Friction Coefficient (M U ) , Static Dynamic Friction Ratio (R ) , and YoungsModulu s (E ) on gear stiffness were discussed; regarding structure, the influence of various gear shapes on gear stiffness was discussed. Especially, because of the

14、unavoidable manufacture defects by machining, there are defect s at the tooth root, as showing, Fig.2. In simulation ,the same defects were also considered. Fig. 1Model layouts(a) Standard, (b) Symmetry 2, (c) Symmetry 4, (d) Offset 2,(e) Offset 4, (f) Trapezium tooth and Hitter2:Equation of Stiffne

15、ss CalculationIn experiment, because the practical shaft is no t absolute rigid body, when hitter is driving gear at the tooth with an angle , shaft will also rotate with an angle . If the radius of pitch circle is r, thenHere, U Y means the node displace mention pitch circle. So, the experiment sti

16、ffness can be calculated asInsimulation, because shaft is considered as an absolute rigid body, the simulation stiffness can be calculated as3 :The Gear Stiffness Influencing Factors3. 1 Friction ParametersIt is surface contact between gear body and jigs, and the same between too thand hitter. The friction status of these con tact pair has sign if I cant influence on gear stiffness. The friction status can be described