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1、外文资料翻译学生姓名： 崔华星 专业班级： 07级机制04班 指导教师： 杨庆山 河北工程大学机电学院年 月Reduction of noise of loaded and unloaded misaligned gear drives AbstractTransmission errors are considered as the main source of vibration and noise of gear drives. The impact of two main functions of transmission errors on noise is investigated
2、: (i) a linear one, caused by errors of alignment, and (ii) a predesigned parabolic function of transmission errors, applied for reduction of noise. It is shown that a linear function of transmission errors is accompanied with edge contact, and then inside the cycle of meshing, the meshing becomes a
3、 mixed one: (i) as surface-to-surface tangency, and (ii) surface-to-curve meshing when edge contact starts. Application of a predesigned parabolic function of transmission errors enables to absorb the linear functions of transmission errors caused by errors of alignment, reduce noise, and avoid edge
4、 contact. The influence of the load on the function of transmission errors is investigated. Elastic deformations of teeth enable to reduce the maximal transmission errors in loaded gear drives. Computerized simulation of meshing and contact is developed for loaded and unloaded gear drives. Numerical
5、 examples for illustration of the developed theory are provided. Keywords: Gear drives; Transmission errors; Tooth contact analysis (TCA); Finite element analysis; Reduction of noise Article Outline1. Introduction 2. Modification of tooth surfaces 2.1. Helical gear drives 2.2. Spiral bevel gears 2.3
6、. Worm gear drives with cylindrical worm3. Types of meshing and basic functions of transmission errors 4. Transmission errors of a loaded gear drive 4.1. Preliminary considerations 4.2. Application of finite element analysis for determination of function of transmission errors of a loaded gear drive
7、5. Numerical examples 6. Comparison of the power of noise for two functions of transmission errors 6.1. Conceptual consideration of applied approach 6.2. Interpolation by a piecewise linear function7. Conclusion Acknowledgements References1. IntroductionSimulation of meshing of gear drives performed
8、 by application of tooth contact analysis (TCA) and test of gear drives have confirmed that transmission errors are the main source of vibrations of the gear box and such vibrations cause the noise of gear drive 1, 2, 4, 5, 6, 7, 10 and 11. The shape of functions of transmission errors depends on th
9、e type of errors of alignment and on the way of modification of gear tooth surfaces performed for improvement of the drive (see Section 2). The reduction of noise proposed by the authors is achieved as follows: (1) The bearing contact of tooth surfaces is localized.(2) A parabolic function of transm
10、ission errors is provided. This allows to absorb linear functions of transmission errors caused by misalignment 7.(3) One of the pair of mating surfaces is modified by double-crowning (see Section 2). This allows usually to avoid edge contact (see Section 5).The authors have compared the results of
11、application of TCA for loaded and unloaded gear drives. It is shown that transmission errors of a loaded gear drive are reduced. The developed approach is illustrated with numerical examples (see Section 5). 2. Modification of tooth surfacesReduction of noise of a gear drive requires modification of
12、 one of the pair of contacting surfaces. The surface modification is illustrated for three types of gear drives: helical gears, spiral bevel gears, and worm gear drives. 2.1. Helical gear drivesProfile crowning of helical gears may be illustrated considering that the mating surfaces are generated by
13、 two rack-cutters with mismatched profiles 5 and 7. Profile crowning allows to localize the bearing contact. Double-crowning in comparison with profile crowning allows to: (i) avoid edge contact (caused by errors of crossing angle and different helix angles of mating gears), and (ii) provide a parab
14、olic function of transmission errors. Double-crowning is performed by plunging of the disk that generates the pinion (see details in Chapter 15 of Ref. 7).2.2. Spiral bevel gearsLocalization of contact of generated spiral bevel gears is provided by application of two mismatched head-cutters p and g
15、used for generation of the pinion and the gear, respectively 7. Two head-cutters p and g have a common line C of generating tooth surfaces (in the case when profile crowning is provided). In the case of double-crowning, the mismatched generating surfaces p and g of the head-cutters have only a commo
16、n single point of tangency, but not a line of tangency. Double-crowning of a generated gear may be achieved by tilting of one of the pair of generating head-cutters, or by proper installment of one of the head-cutters. It is very popular for the modern technology that during the generation of one of the mating gears, us
