机械专业论文中英文.doc

邵阳学院机械工程专业英语论文

Gearbox Noise —— Correlation with Transmission Error and Influence of Bearing Preload
变速箱噪声——相关的传输错误和轴承预压的影响

摘要
ABSTRACT
The five appended papers all deal with gearbox noise and vibration. The first paper presents a review of previously published literature on gearbox noise and vibration.
The second paper describes a test rig that was specially designed and built for noise testing of gears. Finite element analysis was used to predict the dynamic properties of the test rig, and experimental modal analysis of the gearbox housing was used to verify the theoretical predictions of natural frequencies.In the third paper, the influence of gear finishing method and gear deviations on gearbox noise is investigated in what is primarily an experimental study. Eleven test gear pairs were manufactured using three different finishing methods. Transmission error, which is considered to be an important excitation mechanism for gear noise, was measured as well as predicted. The test rig was used to measure gearbox noise and vibration for the different test gear pairs. The measured noise and vibration levels were compared with the predicted and measured transmission error. Most of the experimental results can be interpreted in terms of measured and predicted transmission error. However, it does not seem possible to identify one single parameter,such as measured peak-to-peak transmission error, that can be directly related to measured noise and vibration. The measurements also show that disassembly and reassembly of the gearbox with the same gear pair can change the levels of measured noise and vibration considerably.This finding indicates that other factors besides the gears affect gear noise.In the fourth paper, the influence of bearing endplay or preload on gearbox noise and vibration is investigated. Vibration measurements were carried out at torque levels of 140 Nm and 400Nm, with 0.15 mm and 0 mm bearing endplay, and with 0.15 mm bearing preload. The results show that the bearing endplay and preload influence the gearbox vibrations. With preloaded bearings, the vibrations increase at speeds over 2000 rpm and decrease at speeds below 2000 rpm, compared with bearings with endplay. Finite element simulations show the same tendencies as the measurements.The fifth paper describes how gearbox noise is reduced by optimizing the gear geometry for decreased transmission error. Robustness with respect to gear deviations and varying torque is considered in order to find a gear geometry giving low noise in an appropriate torque range despite deviations from the nominal geometry due to manufacturing tolerances. Static and dynamic transmission error, noise, and housing vibrations were measured. The correlation between dynamic transmission error, housing vibrations and noise was investigated in speed sweeps from 500 to 2500 rpm at constant torque. No correlation was found between dynamic transmission error and noise. Static loaded transmission error seems to be correlated with the ability of the gear pair to excite vibration in the gearbox dynamic system.
论文描述了该试验台是专门设计和建造噪音齿轮测试。有限元分析，用于预测试验台的动态特性和实验的变速箱壳体模态分析用于验证自然试验台。这第三个文件，齿轮精加工方法和变速箱齿轮的偏差影响的理论预测噪声主要是研究在什么的实验研究。十对被测试设备制造使用三种不同的整理方法。传输错误，这被认为是一个重要的激励机制齿轮噪音，测量以及预测。该试验台是用于测量变速箱噪音及不同的测试装置对振动。测得的噪音和振动水平进行比较，预测和实测的传输错误。实验结果大多可以解释和预测传输测量误差项。但是，它似乎并不能够确定一个单一的参数，如测得的峰 - 峰值传输错误，可直接与测得的噪声和振动。测量结果还显示，拆卸和使用相同的变速箱齿轮副重组可以改变测得噪声和振动.这个水平发现表明，除了其他因素的影响齿轮齿轮噪音。第四，轴承影响或变速箱噪音和振动预紧力进行了调查。振动测量均在140牛米和400nm的扭矩水平，用0.15毫米和0毫米轴承间隙，并用0.15 mm轴承预紧力。结果表明，轴承间隙和预紧力影响变速箱的振动。预装轴承，振动增加超过2000转和2000转的速度低于下降速度，相比与轴端间隙轴承。有限元模拟表现出同样的倾向作为测量值。第五本文介绍如何通过优化变速箱噪声为减少传输错误齿轮几何减少。关于齿轮偏差和不同扭矩的鲁棒性考虑，以便找到一个齿轮几何给予尽管从名义几何由于制造公差偏差范围内以适当的扭矩，噪音低。静态和动态的传输错误，噪声，振动测量和该。之间的动态传输错误，房屋振动和噪声的相关性研究了扫描速度从500到2500在恒转矩转速。没有相关关系的动态传递误差和噪声。静态加载的传输错误似乎与齿轮副的能力，激发动力系统中的齿轮箱振动相关。
Keywords: gear, gearbox, noise, vibration, transmission error, bearing preload.
关键词：齿轮，变速箱，噪声，振动，传输错误，轴承预紧力。
1 INTRODUCTION
1 引言
1.1 Background
Noise is increasingly considered an environmental issue. This belief is reflected in demands for lower noise levels in many areas of society, including the working environment. Employees spend a lot of time in this environment and noise can lead not only to hearing impairment but also to decreased ability to concentrate, resulting in decreased productivity and an increased risk of accidents. Quality, too, has become increasingly important. The quality of a product can be defined as its ability to fulfill customers’ demands. These demands often change over time, and the best competitors in the market will set the standard.Noise concerns are also expressed in relation to construction machinery such as wheel loaders and articulated haulers. The gearbox is sometimes the dominant source of noise in these machines.Even if the gear noise is not the loudest source, its pure high frequency tone is easily distinguished from other noise sources and is often perceived as unpleasant. The noise creates an impression of poor quality. In order not to be heard, gear noise must be at least 15 dB lower than other noise sources, such as engine noise.
1.1背景
噪音是越来越认为是环境问题。这种信念体现在许多领域中的社会，包括工作环境，降低噪音水平的要求。在这种环境下员工花了很多时间和噪声不仅会导致听力损伤，而且要集中能力下降，生产力下降和事故造成的风险增加。质量也变得越来越重要。一个产品的质量可以被定义为有能力满足客户的需求。这些要求往往随时间而改变，而在市场上最好的竞争对手将设置标准。噪音问题也涉及到工程机械的轮式装载机和铰接式这样表示。变速箱是有时在这些机械中。甚至噪音的主要来源，如果齿轮噪音并不是最响亮的来源，它的纯高频音很容易区别于其他噪声源，通常为不愉快的感觉。噪音创建了一个质量差的印象。为了不被听到，齿轮噪声必须至少15分贝外，其他噪声源，例如发动机噪音低
1.2 Gear noise
This dissertation deals with the kind of gearbox noise that is generated by gears under load.This noise is often referred to as “gear whine” and consists mainly of pure tones at high frequencies corresponding to the gear mesh frequency and multiples thereof, which are known as harmonics. A tone with the same frequency as the gear mesh frequency is designated the gear mesh harmonic, a tone with a frequency twice the gear mesh frequency is designated the second harmonic, and so on. The term “gear mesh harmonics” refers to all multiples of the gear mesh frequency.Transmission error (TE) is considered an important excitation mechanism for gear whine. Welbourn [1] defines transmission error as “the difference between the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate.” Transmission error may be expressed as angular displacement or as linear displacement at the pitch point. Transmission error is caused by deflections, geometric errors, and geometric modifications.In addition to gear whine, other possible noise-generating mechanisms in gearboxes include gear rattle from gears running against each other without load, and noise generated by bearings.In the case of automatic gearboxes, noise can also be generated by internal oil pumps and by clutches. None of these mechanisms are dealt with in this work, and from now on “gear noise” or “gearbox noise” refers to “gear whine”. MackAldener [2] describes the noise generation process from a gearbox as consisting of three parts: excitation, transmission, and radiation. The origin of the noise is the gear mesh, in which vibrations are created (excitation), mainly due to transmission error. The vibrations are transmitted via the gears, shafts, and bearings to the housing (transmission). The housing vibrates, creating pressure variations in the surrounding air that are perceived as noise (radiation).Gear noise can be affected by changing any one of these three mechanisms. This dissertation deals mainly with excitation, but transmission is also discussed in the section of the literature survey concerning dynamic models, and in the modal analysis of the test gearbox in Paper B. Transmission of vibrations is also investigated in Paper D, which deals with the influence of bearing endplay or preload on gearbox noise. Differences in bearing preload influence a bearing’s dynamic properties like stiffness and damping. These properties also affect the vibration of the gearbox housing.
1.2齿轮噪音
随着变速箱噪声是一种由下负载。这种噪音齿轮生成此论文交易是通常被称为“齿轮哀鸣”，并包括在高频率所对应的齿轮啮合频率和倍数，这是已知的纯色调为主为谐波。一个与齿轮啮合频率相同的频率音调被指定为谐波齿轮啮合，一个频率音调的两倍齿轮啮合频率被指定为二次谐波，依此类推。术语“谐波齿轮啮合”指的是齿轮啮合频率。变速箱错误（TE）的倍数被认为是重要的激励机制齿轮哀鸣。Welbourn [1]定义为“之间的输出齿轮的实际位置和地位，将占据如果齿轮传动是完美结合的差异。”传输错误传输错误可能表现为角位移或在球场上点线位移。传输错误是由变形，几何误差和几何变动。除了齿轮嗲引起的，其他可能产生噪声的机制，包括在变速箱齿轮嘎嘎从对对方的情况下运行负荷齿轮，噪音轴承的情况下产生的自动变速箱，噪音也可以由内部生成的油泵和离合器。这些机制没有得到处理，在此工作，并从“齿​​轮噪音”或“齿轮箱噪音”现在是指“齿轮哀鸣”。奥尔登 描述了从以三部分组成的变速箱噪音的产生过程：激发，传播和辐射。噪声的来源是齿轮啮合，其中振动产生（激励），主要是由于传输错误。的振动传输通过齿轮，轴和轴承的该（传输）。该震动，创造了周围的空气都作为噪声（辐射）感知压力的变化。齿轮噪音可以通过改变任何这三种机制之一的影响。本论文主要涉及激励，但传输也是在文献关于动态模型统计调查组讨论，并在文件中B.振动模态分析传输测试变速箱也是，这与交易调查影响轴承的轴端间隙或变速箱噪音预紧力。轴承预紧力影响的差异像轴承刚度和阻尼的动态特性。这些属性也影响了变速箱外壳的振动。
1.3 Objective
The objective of this dissertation is to contribute to knowledge about gearbox noise. The following specific areas will be the focus of this study:
1. The influence of gear finishing method and gear modifications and errors on noise and vibration from a gearbox.
2. The correlation between gear deviations, predicted transmission error, measured transmission error, and gearbox noise.
3. The influence of bearing preload on gearbox noise.
4. Optimization of gear geometry for low transmission error, taking into consideration robustness with respect to torque and manufacturing tolerances.
1.3目标
本论文的目的是帮助有关变速箱噪声的知识以下具体领域将是本研究的重点：
1.齿轮的加工方法和齿轮噪音和修改，并从变速箱振动误差的影响。
2.齿轮之间的偏差的相关性，预测传输错误，传输测量误差和变速箱噪音。
3.对变速箱的噪声影响轴承预紧力。
4.齿轮低传输错误几何优化，同时考虑到稳健性方面的扭矩和制造公差。
2 AN INDUSTRIAL APPLICATION − TRANSMISSION NOISE REDUCTION
2 工业应用 - 传输降噪
2.1 Introduction
This section briefly describes the activities involved in reducing gear noise from a wheel loader transmission. The aim is to show how the optimization of the gear geometry described in Paper E is used in an industrial application. The author was project manager for the “noise work team” and performed the gear optimization.
One of the requirements when developing a new automatic power transmission for a wheel loader was improving the transmission gear noise. The existing power transmission was known to be noisy. When driving at high speed in fourth gear, a high frequency gear-whine could be heard. Thus there were now demands for improved sound quality. The transmission is a typical wheel loader power transmission, consisting of a torque converter, a gearbox with four forward speeds and four reverse speeds, and a dropbox partly integrated with the gearbox.The dropbox is a chain of four gears transferring the powerto the output shaft. The gears are engaged by wet multi-disc clutches actuated by the transmission hydraulic and control system.
2.1简介
本节简要介绍了减少从轮式装载机传动齿轮噪音所涉及的活动。其目的是展示如何在文件中所述的齿轮结构优化在工业应用。作者是项目经理“噪音工作队”，并进行了齿轮的优化。在发展的要求为轮式装载机新的自动输电之一就是提高传动齿轮的噪音。现有的电力传输被称为是嘈杂。当在四档高速驾驶，高频齿轮嗲可闻。因此，现在有改善音质的要求。传输是一种典型的轮式装载机动力传输，扭矩转换器，带有四个前进速度和四速变速箱扭转，部分与变速箱。升降梭箱升降梭箱是一个集成了四个转移功率到输出轴齿轮链组成。所从事的齿轮由湿式多盘由液压传动和控制系统驱动离合器。此液压系统油是由内部提供的石油由输入轴驱动泵。
2.2 Gear noise target for the new transmission
Experience has shown that the high frequency gear noise should be at least 15 dB below other noise sources such as the engine in order not to be perceived as disturbing or unpleasant.Measurements showed that if the gear noise could be decreased by 10 dB, this criterion should be satisfied with some margin. Frequency analysis of the noise measured in the driver's cab showed that the dominant noise from the transmission originated from the dropbox gears. The goal for transmission noise was thus formulated as follows: “The gear noise (sound pressure level) from the dropbox gears in the transmission should be decreased by 10 dB compared to the existing transmission in order not to be perceived as unpleasant. It was assumed that it would be necessary to make changes to both the gears and the transmission housing in order to decrease the gear noise sound pressure level by 10 dB.
2.2齿轮传动噪声的新目标
经验表明，高频齿轮噪音至少应为15分贝以下，如发动机等噪声源分贝，以免被视为干扰或不愉快的。测量值表明，如果齿轮噪音可降低10分贝，这个标准应该满足于一定的余量。频率在驾驶室测量的噪声分析表明，从传输主要的噪音从投寄箱齿轮起源。对传输噪声的目标是这样表述为如下：“齿轮噪音在传输的升降梭箱齿轮（声压级）应10分贝下降相比，以现有的传输不被视为不愉快的感觉。”位置在投寄箱齿轮。有人认为有必要使这两个齿轮和变速器壳体的变化，以减少齿轮噪音10分贝的声压水平。
2.3 Noise and vibration measurements
In order to establish a reference for the new transmission, noise and vibration were measured for the existing transmission. The transmission is driven by the same type of diesel engine used in a wheel loader. The engine and transmission are attached to the stand using the same rubber mounts that are used in a wheel loader in order to make the installation as similar as possible to the installation in a wheel loader. The output shaft is braked using an electrical brake.

2.3噪声和振动测量
为了建立一个新的传输参考，噪音和振动测量的现有传输。传输是由相同的柴油发动机在轮式装载机的类型。发动机和变速器连接到使用相同的立场是在一个橡胶轮式装载机使用，以使安装尽可能类似的安装在轮式装载机坐骑。输出轴制动采用电气制动。
2.4 Optimization of gears
Noise-optimized dropbox gears were designed by choosing macro- and microgeometries giving lower transmission error than the original (reference) gears. The gear geometry was chosen to yield a low transmission error for the relevant torque range, while also taking into consideration variations in the microgeometry due to manufacturing tolerances. The optimization of one gear pair is described in more detail in Paper E.Transmission error is considered an important excitation mechanism for gear whine. Welbourn [1] defines it as “the difference between the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate.” In this project the aim was to reduce the maximum predicted transmission error amplitude at gear mesh frequency (first harmonic of gear mesh frequency) to less than 50% of the value for the reference gear pair. The first harmonic of transmission error is the amplitude of the part of the total transmission error that varies with a frequency equal to the gear mesh frequency. A torque range of
100 to 500 Nm was chosen because this is the torque interval in which the gear pair generates noise in its design application. According to Welbourn [1], a 50% reduction in transmission error can be expected to reduce gearbox noise by 6 dB (sound pressure level, SPL). Transmission error was calculated using the LDP software (Load Distribution Program) developed at the Gear Laboratory at Ohio State University [3].The “optimization” was not strictly mathematical. The design was optimized by calculating the transmission error for different geometries, and then choosing a geometry that seemed to be a good compromise, considering not only the transmission error, but also factors such asstrength, losses, weight, cost, axial forces on bearings, and manufacturing.
When choosing microgeometric modifications and tolerances, it is important to take manufacturing options and cost into consideration. The goal was to use the same finishing method for the optimized gears as for the reference gears, namely grinding using a KAPP VAS 531 and CBN-coated grinding wheels.For a specific torque and gear macrogeometry, it is possible to define a gear microgeometry that minimizes