外文翻譯---計算機控制插齒刀加工橢圓齒輪齒形

1、英文部分Computerized tooth profile generation of elliptical gears manufactured by shaper cuttersBiing-Wen BairDepartment of Mechanical Engineering, National Lien Ho Institute of Technology,AbstractThis work simulates an elli

2、ptical gear drive, the axis of rotation of which is coincident with its geometric center, manufactured by shaper cutters. The mathematical model of an elliptical gear is developed based on the theory of gearing and gear

3、generation mechanisms. In addition, the tooth undercutting of the gear is also investigated based on the developed mathematical model of the elliptical gear, its unit normal vectors and a numerical method. A geometric re

4、lationship is developed and applied to prevent the occurrence of pointed teeth on elliptical gears. Further, this study also develops computer simulation programs to generate the tooth profile of elliptical gears without

5、 tooth undercutting and pointed teeth. Comparison of the angular velocity variations of the elliptical gear drives is also made. The results show that the developed elliptical gear drive can be utilized as an oil pump wi

6、th a larger pumping volume and less angular velocity variation. © 2002 Elsevier Science B.V. All rights reserved.Keywords: Elliptical gears; Undercutting; Pointed teeth1. IntroductionAn elliptical gear drive, the ro

7、tation center of which coincides with one of its foci, is kinematically equivalent to the crossed link, and can be used to produce irregular rotations. In addition, it is well known for providing excellent characteristic

8、s such as accurate transmission, compact size, and ease of dynamic balance. Hence, elliptical gear drives have been applied successfully in various types of automatic machinery, quick-return mechanisms, packaging machine

9、s, and printing presses [1]. This type of gearing can also be used to develop non-circular gears, which belong to high-order elliptical pitch curves. Second- order elliptical gear drives, the rotation center of which coi

10、ncides with one of its foci, can find use in the design of instruments such as pumps and flow meters [1]. However, this type of gear set has two speed changes for each revolution, these two-cycle variations inducing a wa

11、ve fluctuation that is so rotation axis is one of its foci, is one in which the driving elliptical gear performs n revolutions for one revolution of the driven non- circular gear. A second-order elliptical gear (type 2)

12、 is defined as n = 2. Under the same eccentricity and major axis, the size of the type 1 elliptical gears is smaller than that of the type 2. Further, if the type 1 elliptical gear set is applied to oil pumps, the wave f

13、luctuation of the pumping oil is smaller and smoother than that of the other type. The elliptical gear tooth profile is usually produced by a hob- bing or shaping machine with a hob cutter or shaper cutter. This study si

14、mulates the manufacture of elliptical gears via a shaper cutter on a shaping machine. It is known that if a spur gear is produced by a shaper, the profile of the shaper cutter should be the same as that of the mating spu

15、r gear. Therefore, the mathematical model of a shaper cutter is the same as that of a spur gear, which can be derived from the generation mechanism with a rack cutter. According to the theory of gearing, the mathematica

16、l models of elliptical gear tooth profiles, which rotate about their geometric center (type 1), are developed based on the proposed generation mechanism with shaper cutters. Due to the complex characteristics of t

17、his type of elliptical gear, undercutting and pointed teeth may exist on its tooth profile. The tooth undercutting of this type of elliptical gear is affected by its pressure angle, number of teeth, module, and major axi

18、s. The strength of the gear tooth root can be increased by applying a positive-shifted modification for the cutter during the gear generation. However, an over-positive-shifted modification may result in the appear- ance

19、 of pointed teeth. Pointed teeth are generated when the right- and left-side involute tooth profiles intersect on or below the addendum circle of the gear. Further, the pointed teeth are usually generated on the two majo

20、r axis of an elliptical gear. If a profile index is defined to prevent pointed teeth generation on the two major axis of an elliptical gear, then no other pointed tooth will be generated for all elliptical gear pr

21、ofiles. Thus, the computer program developed here can calculate and provide proper design parameters for the designed elliptical gears to avoid tooth undercutting and pointed teeth.2. Mathematical model of the elliptical

22、 gear surfacesShaper cutters are used to generate elliptical gears, and the profiles of shaper cutters are the same as those of spur gears. Hence, the mathematical model of the shaper cutter is the same as that of the sp