第一篇：機械類專業課程名稱中英文對照

機械制圖 Mechanical Drawing

可編程序控制技術 Controlling Technique for Programming

金工實習Metal Working Practice

畢業實習Graduation Practice理論力學 Theoretical Mechanics

材料力學 Material Mechanics

數字電子電路 Fundamental Digital Circuit

機械控制工程 Mechanical Control Engineering

可靠性工程 Reliability Engineering

機械工程測試技術 Measurement Techniques of Mechanic Engineering

計算機控制系統 Computer Control System

機器人技術基礎 Fundamentals of Robot Techniques

最優化技術 Techniques of Optimum

工程測試與信號處理 Engineering Testing & Signal Processing

金屬工藝及設計 Metal Technics & Design

機械工業企業管理 Mechanic Industrial Enterprise Management

機械零件課程設計 Course Design of Machinery Elements

投資經濟學 Investment Economics

現代企業管理 Modern Enterprise Administration

市場營銷學 Market Selling生產實習Production Practice

課程設計 Course Exercise

有限元法 FInite Element

金工實習Metalworking Practice

液壓傳動 Hydraulic Transmission微機原理及接口技術 Principle & Interface Technique of Micro-computer微機原理及接口技術 Principle & Interface Technique of Micro-computer

數控技術 Digit Control Technique活塞膨脹機 Piston Expander

活塞式制冷壓縮機 Piston Refrigerant Compreessor

活塞式壓縮機 Piston Compressor

活塞式壓縮機基礎設計 Basic Design of Piston Compressor

活塞壓縮機結構強度 Structural Intensity of Piston Compressor

活賽壓機氣流脈動 Gas Pulsation of Piston Pressor

貨幣銀行學 Currency Banking

基本電路理論 Basis Theory of Circuit

基礎寫作 Fundamental Course of Composition

機床電路 Machine Tool Circuit

機床電器 Machine Tool Electric Appliance

機床電氣控制 Electrical Control of Machinery Tools

機床動力學 Machine Tool Dynamics

機床設計 Machine Tool design

機床數字控制 Digital Control of Machine Tool

機床液壓傳動 Machinery Tool Hydraulic Transmission

機電傳動 Mechanical & Electrical Transmission

機電傳動控制 Mechanical & electrical Transmission Control

機電耦合系統 Mechanical & Electrical Combination System

機電系統計算機仿真 Computer Simulation of Mechanic/Electrical Systems

機電一體化 Mechanical & Electrical Integration

機構學 Structuring

機器人 Robot

機器人控制技術 Robot Control Technology

機械產品學 Mechanic Products

機械產品造型設計 Shape Design of Mechanical Products

機械工程控制基礎 Basic Mechanic Engineering Control

機械加工自動化 Automation in Mechanical Working

機械可靠性 Mechanical Reliability

機械零件 Mechanical Elements

機械零件設計 Course Exercise in Machinery Elements Design

機械零件設計基礎 Basis of Machinery Elements Design

機械設計 Mechanical Designing

機械設計基礎 Basis of Mechanical Designing

機械設計課程設計 Course Exercise in Mechanical Design

機械設計原理 Principle of Mechanical Designing

機械式信息傳輸機構 Mechanical Information Transmission Device

機械原理 Principle of Mechanics

機械原理和機械零件 Mechanism & Machinery

機械原理及機械設計 Mechanical Designing

機械原理及應用 Mechanical Principle & Mechanical Applications

機械原理課程設計 Course Exercise of Mechanical Principle

機械原理與機械零件 Mechanical Principle and Mechanical Elements

機械原理與機械設計 Mechanical Principle and Mechanical Design

機械噪聲控制 Control of Mechanical Noise

機械制造概論 Introduction to Mechanical Manufacture

機械制造工藝學 Technology of Mechanical Manufacture

機械制造基礎 Fundamental of Mechanical Manufacture

機械制造基礎(金屬工藝學)Fundamental Course of Mechanic Manufacturing(Meta

機械制造系統自動化 Automation of Mechanical Manufacture System

機械制造中計算機控制 Computer Control in Mechanical Manufacture

互換性與技術測量 Elementary Technology of Exchangeability Measurement焊接方法 Welding Method

焊接方法及設備 Welding Method & Equipment

焊接檢驗 Welding Testing

焊接結構 Welding Structure

焊接金相 Welding Fractography

焊接金相分析 Welding Fractography Analysis

焊接冶金 Welding Metallurgy

焊接原理 Fundamentals of Welding

焊接原理及工藝 Fundamentals of Welding & Technology

焊接自動化 Automation of Welding工程材料的力學性能測試 Mechanic Testing of Engineering Materials

工程材料及熱處理 Engineering Material and Heat Treatment

工程材料學 Engineering Materials

工程測量 Engineering Surveying

工程測試技術 Engineering Testing Technique

工程測試實驗 Experiment on Engineering Testing工程測試信息 Information of Engineering Testing工程動力學 Engineering Dynamics

工程概論 Introduction to Engineering

工程概預算 Project Budget

工程經濟學 Engineering Economics

工程靜力學 Engineering Statics

工程力學 Engineering Mechanics

工程熱力學 Engineering Thermodynamics

工程項目評估 Engineering Project Evaluation

工程優化方法 Engineering Optimizational Method工程運動學 Engineering Kinematics

工程造價管理 Engineering Cost Management

工程制圖 Graphing of Engineering電機學 Electrical Motor電機學及控制電機 Electrical Machinery Control & Technology

第二篇：機械名稱中英文對照

一、除大塊機Eliminates the bulk machine

二、齒型篩分除雜物機The screening and eliminates the sundry goods machine

三、振動煤箅Vibration Coal Grate

四、滾軸篩Roller Screen

五、滾筒篩Trommel Screen

六、振動概率篩Vibration Probability Screen

七、減振平臺Antivibration Platform

八、布料器Distributing Device

九、皮帶機頭部伸縮裝置Conveyer Belt Telescopiform Device

十、膠帶給料機Belt Feeder

十一、往復式給料機Reciprocating Feeder

十二、振動給煤機Vibrator Feeder

十三、葉輪給煤機Coal Impeller Feeder

十四、埋刮板輸送機Buried Scraper Conveyer

十五、螺旋輸送機Screw Conveyer

十六、板式喂料機Apron Feeder

十七、緩沖彈簧板式大塊輸送機Buffer Spring Apron Bulk Converyor

十八、斗式提升機Chain-Bucket Elevator

十九、TD75、DTⅡ型帶式輸送機Type TD75/DTII Belt Conveyer

二十、電動三通3-Through-Chute With Electric Drive Gate 二

十一、重力式煤溝擋板Gravity Type Coal Ditch Baffle

二十二、物料穩流器Material Constant Staticizer

二十三、犁式卸料器、刮水器Plough Type Tripper/Wiper 二

十四、棧橋沖洗器Flusher

二十五、噴霧除塵系統Exhaust System 二

十六、緩沖鎖氣器Buffer Air Lock 二

十七、緩沖滾筒Snub Pulley二十八、二十九、三

十、緩沖平臺Buffer Platform 膠帶防撕裂保護裝置Belt Protective Device 鏈斗卸車機Bucket-Chain Unloader

第三篇：機械專業英語文章中英文對照

英語原文

NUMERICAL CONTROL

Numerical control(N/C)is a form of programmable automation in which the processing equipment is controlled by means of numbers, letters, and other symbols, The numbers, letters, and symbols are coded in an appropriate format to define a program of instructions for a particular work part or job.When the job changes, the program of instructions is changed.The capability to change the program is what makes N/C suitable for low-and medium-volume production.It is much easier to write programs than to make major alterations of the processing equipment.There are two basic types of numerically controlled machine tools：point—to—point and continuous—path(also called contouring).Point—to—point machines use unsynchronized motors, with the result that the position of the machining head Can be assured only upon completion of a movement, or while only one motor is running.Machines of this type are principally used for straight—line cuts or for drilling or boring.The N/C system consists of the following components：data input, the tape reader with the control unit, feedback devices, and the metal—cutting machine tool or other type of N/C equipment.Data input, also called “man—to—control link”, may be provided to the machine tool manually, or entirely by automatic means.Manual methods when used as the sole source of input data are restricted to a relatively small number of inputs.Examples of manually operated devices are keyboard dials, pushbuttons, switches, or thumbwheel selectors.These are located on a console near the machine.Dials ale analog devices usually connected to a syn-chro-type resolver or potentiometer.In most cases, pushbuttons, switches, and other similar types of selectors are digital input devices.Manual input requires that the operator set the controls for each operation.It is a slow and tedious process and is seldom justified except in elementary machining applications or in special cases.In practically all cases, information is automatically supplied to the control unit and the machine tool by cards, punched tapes, or by magnetic tape.Eight—channel punched paper tape is the most commonly used form of data input for conventional N/C systems.The coded instructions on the tape consist of sections of punched holes called blocks.Each block represents a machine function, a machining operation, or a combination of the two.The entire N/C program on a tape is made up of an accumulation of these successive data blocks.Programs resulting in long tapes all wound on reels like motion-picture film.Programs on relatively short tapes may be continuously repeated by joining the two ends of the tape to form a loop.Once installed, the tape is used again and again without further handling.In this case, the operator simply loads and1

unloads the parts.Punched tapes ale prepared on type writers with special tape—punching attachments or in tape punching units connected directly to a computer system.Tape production is rarely error-free.Errors may be initially caused by the part programmer, in card punching or compilation, or as a result of physical damage to the tape during handling, etc.Several trial runs are often necessary to remove all errors and produce an acceptable working tape.While the data on the tape is fed automatically, the actual programming steps ale done manually.Before the coded tape may be prepared, the programmer, often working with a planner or a process engineer, must select the appropriate N/C machine tool, determine the kind of material to be machined, calculate the speeds and feeds, and decide upon the type of tooling needed.The dimensions on the part print are closely examined to determine a suitable zero reference point from which to start the program.A program manuscript is then written which gives coded numerical instructions describing the sequence of operations that the machine tool is required to follow to cut the part to the drawing specifications.The control unit receives and stores all coded data until a complete block of information has been accumulated.It then interprets the coded instruction and directs the machine tool through the required motions.The function of the control unit may be better understood by comparing it to the action of a dial telephone, where, as each digit is dialed, it is stored.When the entire number has been dialed, the equipment becomes activated and the call is completed.Silicon photo diodes, located in the tape reader head on the control unit, detect light as it passes through the holes in the moving tape.The light beams are converted to electrical energy, which is amplified to further strengthen the signal.The signals are then sent to registers in the control unit, where actuation signals are relayed to the machine tool drives.Some photoelectric devices are capable of reading at rates up to 1000 characters per second.High reading rates are necessary to maintain continuous machine—tool motion；otherwise dwell marks may be generated by the cutter on the part during contouring operations.The reading device must be capable of reading data blocks at a rate faster than the control system can process the data.A feedback device is a safeguard used on some N/C installations to constantly compensate for errors between the commanded position and the actual location of the moving slides of the machine tool.An N/C machine equipped with this kind of a direct feedback checking device has what is known as a closed-loop system.Positioning control is accomplished by a sensor which, during the actual operation, records the position of the slides and relays this information back to the control unit.Signals thus received ale compared to input signals on the tape, and any discrepancy between them is automatically rectified.In an alternative system, called an open—loop system, the machine is positioned solely by stepping motor drives in response to commands by a controllers.There is one basic type of NC motions.Point-to-point or Positional Control In point-to-point control the machine tool elements(tools, table, etc.)are moved to programmed locations and the machining operations performed

after the motions are completed.The path or speed of movement between locations is unimportant;only the coordinates of the end points of the motions are accurately controlled.This type of control is suitable for drill presses and some boring machines, where drilling, tapping, or boring operations must be performed at various locations on the work piece.Straight-Line or Linear Control Straight-Line control systems are able to move the cutting tool parallel to one of the major axes of the machine tool at a controlled rate suitable for machining.It is normally only possible to move in one direction at a time, so angular cuts on the work piece are not possible, consequently, for milling machines, only rectangular configurations can be machined or for lathes only surfaces parallel or perpendicular to the spindle axis can be machined.This type of controlled motion is often referred to as linear control or a half-axis of control.Machines with this form of control are also capable of point-to-point control.The original N/C used the closed—loop system.Of the two systems, closed and open loop, closed loop is more accurate and, as a consequence, is generally more expensive.Initially, open—loop systems were used almost entirely for light-duty applications because of inherent power limitations previously associated with conventional electric stepping motors.Recent advances in the development of electro hydraulic stepping motors have led to increasingly heavier machine load applications.中文譯文

數控技術

數控是可編程自動化技術的一種形式,通過數字、字母和其他符號來控制加工設備。數字、字母和符號用適當的格式編碼為一個特定工件定義指令程序。當工件改變時,指令程序就改變。這種改變程序的能力使數控適合于中、小批量生產,寫一段新程序遠比對加工設備做大的改動容易得多。

數控機床有兩種基本形式：點位控制和連續控制(也稱為輪廓控制)。點位控制機床采用異步電動機,因此,主軸的定位只能通過完成一個運動或一個電動機的轉動來實現。這種機床主要用于直線切削或鉆孔、鏜孔等場合。

數控系統由下列組件組成：數據輸入裝置,帶控制單元的磁帶閱讀機,反饋裝置和切削機床或其他形式的數控設備。

數據輸人裝置,也稱“人機聯系裝置”,可用人工或全自動方法向機床提供數據。人工方法作為輸人數據唯一方法時,只限于少量輸入。人工輸入裝置有鍵盤,撥號盤,按鈕,開關或撥輪選擇開關,這些都位于機床附近的一個控制臺上。撥號盤通常連到一個同步解析器或電位計的模擬裝置上。在大多數情況下,按鈕、開關和其他類似的旋鈕是數據輸入元件。人工輸入需要操作者控制每個操作,這是一個既慢又單調的過程,除了簡單加工場合或特殊情況,已很少使用。

幾乎所有情況下,信息都是通過卡片、穿孔紙帶或磁帶自動提供給控制單元。在傳統的數控系統中,八信道穿孔紙帶是最常用的數據輸入形式,紙帶上的編碼指令由一系列稱為程序塊的穿孔組成。每一個程序塊代表一種加工功能、一種操作或兩者的組合。紙帶上的整個數控程序由這些連續數據單元連接而成。帶有程序的長帶子像電影膠片一樣繞在盤子上,相對較短的帶子上的程序可通過將紙帶兩端連接形成一個循環而連續不斷地重復使用。帶子一旦安裝好,就可反復使用而無需進一步處理。此時,操作者只是簡單地上、下工件。穿孔紙帶是在帶有特制穿孔附件的打字機或直接連到計算機上的紙帶穿孔裝置上做成的。紙帶制造很少不出錯,錯誤可能由編程、卡片穿孔或編碼、紙帶穿孔時的物理損害等形成。通常,必須要試走幾次來排除錯誤,才能得到一個可用的工作紙帶。

雖然紙帶上的數據是自動進給的,但實際編程卻是手工完成的,在編碼紙帶做好前,編程者經常要和一個計劃人員或工藝工程師一起工作,選擇合適的數控機床,決定加工材料,計算切削速度和進給速度,決定所需刀具類型,仔細閱讀零件圖上尺寸,定下合適的程序開始的零參考點,然后寫出程序清單,其上記載有描述加工順序的編碼數控指令,機床按順序加工工件到圖樣要求。

控制單元接受和儲存編碼數據,直至形成一個完整的信息程序塊,然后解釋數控指令,并引導機床得到所需運動。

為更好理解控制單元的作用,可將它與撥號電話進行比較,即每撥一個數字,就儲存一個,當整個數字撥好后,電話就被激活,也就完成了呼叫。

裝在控制單元里的紙帶閱讀機,通過其內的硅光二極管,檢測到穿過移動紙帶上的孔漏

過的光線,將光束轉變成電能,并通過放大來進一步加強信號,然后將信號送到控制單元里的寄存器,由它將動作信號傳到機床驅動裝置。

有些光電裝置能以高達每秒1000個字節的速度閱讀,這對保持機床連續動作是必須的,否則,在輪廓加工時,刀具可能在工件上產生劃痕。閱讀裝置必須要能以比控制系統處理數據更快的速度來閱讀數據程序塊。

反饋裝置是用在一些數控設備上的安全裝置,它可連續補償控制位置與機床運動滑臺的實際位置之間的誤差。裝有這種直接反饋檢查裝置的數控機床有一個閉環系統裝置。位置控制通過傳感器實現,在實際工作時,記錄下滑臺的位置,并將這些信息送回控制單元。接受到的信號與紙帶輸入的信號相比較,它們之間的任何偏差都可得到糾正。

在另一個稱為開環的系統中,機床僅由響應控制器命令的步進電動機驅動定位,工件的精度幾乎完全取決于絲杠的精度和機床結構的剛度。有幾個理由可以說明步進電機是一個自動化申請的非常有用的驅動裝置。對于一件事物,它被不連續直流電壓脈沖驅使,是來自數傳計算機和其他的自動化的非常方便的輸出控制系統。當多數是索引或其他的自動化申請所必備者的時候,步進電機對運行一個精確的有角進步也是理想的。因為控制系統不需要監聽就提供特定的輸出指令而且期待系統適當地反應的公開-環操作造成一個回應環,步進電機是理想的。一些工業的機械手使用高抬腿運步的馬乘汽車駕駛員,而且步進電機是有用的在數字受約束的工作母機中。這些申請的大部分是公開-環 ,但是雇用回應環檢測受到驅策的成份位置是可能的。環的一個分析者把真實的位置與需要的位置作比較,而且不同是考慮過的錯誤。那然后駕駛員能發行對步進電機的電脈沖,直到錯誤被減少對準零位。在這個系統中,沒有信息反饋到控制單元的自矯正過程。出現誤動作時,控制單元繼續發出電脈沖。比如,一臺數控銑床的工作臺突然過載,阻力矩超過電機轉矩時,將沒有響應信號送回到控制器。因為,步進電機對載荷變化不敏感,所以許多數控系統設計允許電機停轉。然而,盡管有可能損壞機床結構或機械傳動系統,也有使用帶有特高轉矩步進電機的其他系統,此時,電動機有足夠能力來應付系統中任何偶然事故。

最初的數控系統采用開環系統。在開、閉環兩種系統中,閉環更精確,一般說來更昂貴。起初,因為原先傳統的步進電動機的功率限制,開環系統幾乎全部用于輕加工場合,最近出現的電液步進電動機已越來越多地用于較重的加工領域。

第四篇：機械專業英語詞匯中英文對照

機床 machine tool

金屬工藝學 technology of metals刀具 cutter摩擦 friction聯結 link

傳動 drive/transmission軸 shaft彈性 elasticity

頻率特性 frequency characteristic誤差 error響應 response定位 allocation機床夾具 jig動力學 dynamic運動學 kinematic靜力學 static

分析力學 analyse mechanics拉伸 pulling壓縮 hitting剪切 shear扭轉 twist

彎曲應力 bending stress

強度 intensity

三相交流電 three-phase AC磁路 magnetic circles變壓器 transformer

異步電動機 asynchronous motor幾何形狀 geometrical精度 precision正弦形的 sinusoid交流電路 AC circuit

機械加工余量 machining allowance變形力 deforming force變形 deformation應力 stress硬度 rigidity熱處理 heat treatment退火 anneal正火 normalizing脫碳 decarburization滲碳 carburization電路 circuit

半導體元件 semiconductor element反饋 feedback

發生器 generator

直流電源 DC electrical source門電路 gate circuit邏輯代數 logic algebra

外圓磨削 external grinding內圓磨削 internal grinding平面磨削 plane grinding變速箱 gearbox離合器 clutch絞孔 fraising絞刀 reamer

螺紋加工 thread processing螺釘 screw銑削 mill

銑刀 milling cutter功率 power工件 workpiece

齒輪加工 gear mechining齒輪 gear

主運動 main movement

主運動方向 direction of main movement進給方向 direction of feed

進給運動 feed movement

合成進給運動 resultant movement of feed合成切削運動 resultant movement of cutting

合成切削運動方向 direction of resultant

movement of cutting切削深度 cutting depth前刀面 rake face刀尖 nose of tool前角 rake angle后角 clearance angle龍門刨削 planing主軸 spindle主軸箱 headstock卡盤 chuck

加工中心 machining center車刀 lathe tool車床 lathe鉆削 鏜削 bore車削 turning磨床 grinder基準 benchmark鉗工 locksmith

鍛 forge壓模 stamping焊 weld

拉床 broaching machine拉孔 broaching裝配 assembling鑄造 found

流體動力學 fluid dynamics流體力學 fluid mechanics加工 machining

液壓 hydraulic pressure切線 tangent

機電一體化 mechanotronics mechanical-electrical integration

氣壓 air pressure pneumatic pressure

穩定性 stability

介質 medium

液壓驅動泵 fluid clutch

液壓泵 hydraulic pump

閥門 valve

失效 invalidation

強度 intensity

載荷 load

應力 stress

安全系數 safty factor可靠性 reliability螺紋 thread螺旋 helix鍵 spline銷 pin

滾動軸承 rolling bearing滑動軸承 sliding bearing彈簧 spring

制動器 arrester brake十字結聯軸節 crosshead聯軸器 coupling鏈 chain

皮帶 strap

精加工 finish machining

粗加工 rough machining

變速箱體 gearbox casing

腐蝕 rust

氧化 oxidation

磨損 wear

耐用度 durability

隨機信號 random signal離散信號 discrete signal超聲傳感器 ultrasonic sensor

第五篇：機械專業論文中英文對照

Gearbox Noise?Correlation with Transmission Error and Influence of Bearing Preload

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.Keywords: gear, gearbox, noise, vibration, transmission error, bearing preload.ACKNOWLEDGEMENTS This work was carried out at Volvo Construction Equipment in Eskilstuna and at the Department of Machine Design at the Royal Institute of Technology(KTH)in Stockholm.The work was initiated by Professor Jack Samuelsson(Volvo and KTH), Professor S?ren Andersson(KTH), and Dr.Lars Br?the(Volvo).The financial support of the Swedish Foundation for Strategic Research and the Swedish Agency for Innovation Systems – VINNOVA – is gratefully acknowledged.Volvo Construction Equipment is acknowledged for giving me the opportunity to devote time to this work.Professor S?ren Andersson is gratefully acknowledged for excellent guidance and encouragement.I also wish to express my appreciation to my colleagues at the Department of Machine Design, and especially to Dr.Ulf Sellgren for performing simulations and contributing to the writing of Paper D, and Dr.Stefan Bj?rklund for performing surface finish measurements.The contributions to Paper C by Dr.Mikael

P?rssinen are highly appreciated.All contributionsto this work by colleagues at Volvo are gratefully appreciated.1 INTRODUCTION 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.1.2 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.1.3 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.2 AN INDUSTRIAL APPLICATION ? TRANSMISSION NOISE REDUCTION 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.2.2 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.2.3 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.2.4 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 transmission error.For example, at no load, if there are no pitch errors and no other geometrical deviations, the shape of the gear teeth should be true involute, without modifications like tip relief or involute crowning.For a specific torque, the geometry of the gear should be designed in such a way that it compensates for the differences in deflection related to stiffness variations in the gear mesh.However, even if it is possible to define the optimal gear microgeometry, it may not be possible to manufacture it, given the limitations of gear machining.Consideration must also be given to how to specify the gear geometry in drawings and how to measure the gear in an inspection machine.In many applications there is also a torque range over which the transmission error should be minimized.Given that manufacturing tolerances are inevitable, and that a demand for smaller tolerances leads to higher manufacturing costs, it is important that gears be robust.In other words, the important characteristics, in this case transmission error, must not vary much when the torque is varied or when the microgeometry of the gear teeth varies due to manufacturing tolerances.LDP [3] was used to calculate the transmission error for the reference and optimized gear pair at different torque levels.The robustness function in LDP was used to analyze the sensitivity to deviations due to manufacturing tolerances.The “min, max, level” method involves assigning three levels to each parameter.2.5 Optimization of transmission housing Finite element analysis was used to optimize the transmission housing.The optimization was not performed in a strictly mathematical way, but was done by calculating the vibration of the housing for different geometries and then choosing a geometry that seemed to be a good compromise.Vibration was not the sole consideration, also weight, cost, available space, and casting were considered.A simplified shell element model was used for the optimization to decrease computational time.This model was checked against a more detailed solid element model of the housing to ensure that the simplification had not changed the dynamic properties too much.Experimental modal analysis was also used to find the natural frequencies of the real transmission housing and to ensure that the model did not deviate too much from the real housing.Gears shafts and bearings were modeled as point masses and beams.The model was excited at the bearing positions by applying forces in the frequency range from 1000 to 3000 Hz.The force amplitude was chosen as 10% of the static load from the gears.This choice could be justified because only relative differences are of interest, not absolute values.The finite element analysis was performed by Torbj?rn Johansen at Volvo Technology.The author’s contribution was the evaluation of the results of different housing geometries.A number of measuring points were chosen in areas with high vibration velocities.At each measuring point the vibration response due to the excitation was evaluated as a power spectral density(PSD)graph.The goal of the housing redesign was to decrease the vibrations at all measuring points in the frequency range 1000 to 3000 Hz.2.6 Results of the noise measurements The noise and vibration measurements described in section 2.3 were performed after optimizing the gears and transmission housing.The total sound power level decreased by 4 dB.2.7 Discussion and conclusions It seems to be possible to decrease the gear noise from a transmission by

decreasing the static loaded transmission error and/or optimizing the housing.In the present study, it is impossible to say how much of the decrease is due to the gear optimization and how much to the housing optimization.Answering this question would have required at least one more noise measurement, but time and cost issues precluded this.It would also have been interesting to perform the noise measurements on a number of transmissions, both before and after optimizing the gears and housing, in order to determine the scatter of the noise of the transmissions.Even though the goal of decreasing the gear noise by 10 dB was not reached, the goal of reducing the gear noise in the wheel loader cab to 15 dB below the overall noise was achieved.Thus the noise optimization was successful.3 SUMMARY OF APPENDED PAPERS 3.1 Paper A: Gear Noise and Vibration – A Literature Survey This paper presents an overview of the literature on gear noise and vibration.It is divided into three sections dealing with transmission error, dynamic models, and noise and vibration measurement.Transmission error is an important excitation mechanism for gear noise and vibration.It is defined as “the difference between the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate” [1].The literature survey revealed that while most authors agree that transmission error is an important excitation mechanism for gear noise and vibration, it is not the only one.Other possible time-varying noise excitation mechanisms include friction and bending moment.Noise produced by these mechanisms may be of the same order of magnitude as that produced by transmission error, at least in the case of gears with low transmission error [4].The second section of the paper deals with dynamic modeling of gearboxes.Dynamic models are often used to predict gear-induced vibrations and investigate the effect of changes to the gears, shafts, bearings, and housing.The literature survey revealed that dynamic models of a system consisting of gears, shafts, bearings, and gearbox casing can be useful in understanding and predicting the dynamic behavior of a gearbox.For

relatively simple gear systems, lumped parameter dynamic models with springs, masses, and viscous damping can be used.For more complex models that include such elements as the gearbox housing, finite element modeling is often used.The third section of the paper deals with noise and vibration measurement and signal analysis, which are used when experimentally investigating gear noise.The survey shows that these are useful tools in experimental investigation of gear noise because gears create noise at specific frequencies related to the number of teeth and the rotational speed of the gear.3.2 Paper B: Gear Test Rig for Noise and Vibration Testing of Cylindrical Gears Paper B describes a test rig for noise testing of gears.The rig is of the recirculating power type and consists of two identical gearboxes, connected to each other with two universal joint shafts.Torque is applied by tilting one of the gearboxes around one of its axles.This tilting is made possible by bearings between the gearbox and the supporting brackets.A hydraulic cylinder creates the tilting force.Finite element analysis was used to predict the natural frequencies and mode shapes for individual components and for the complete gearbox.Experimental modal analysis was carried out on the gearbox housing, and the results showed that the FE predictions agree with the measured frequencies(error less than 10%).The FE model of the complete gearbox was also used in a harmonic response analysis.A sinusoidal force was applied in the gear mesh and the corresponding vibration amplitude at a point on the gearbox housing was predicted.3.3 Paper C: A Study of Gear Noise and Vibration Paper C reports on an experimental investigation of the influence of gear finishing methods and gear deviations on gearbox noise and vibration.Test gears were manufactured using three different finishing methods and with different gear tooth modifications and deviations.Table3.3.1 gives an overview of the test gear pairs.The surface finishes and geometries of the gear tooth flanks were measured.Transmission error was measured using a single flank gear tester.LDP software from Ohio State University was used for transmission error computations.The test rig described in Paper B was used to measure gearbox noise and vibration for the different test gear pairs.The measurements showed that disassembly and reassembly of the gearbox with the same gear pair might change the levels of measured noise and vibration.The rebuild variation was sometimes of the same order of magnitude as the differences between different tested gear pairs, indicating that other factors besides the gears affect gear noise.In a study of the influence of gear design on noise, Oswald et al.[5] reported rebuild variations of the same order of magnitude.Different gear finishing methods produce different surface finishes and structures, as well as different geometries and deviations of the gear tooth flanks, all of which influence the transmission error and thus the noise level from a gearbox.Most of the experimental results can be explained in terms of measured and computed transmission error.The relationship between predicted peak-to-peak transmission error and measured noise at a torque level of 500 Nm is shown in Figure 3.3.1.There appears to be a strong correlation between computed transmission error and noise for all cases except gear pair K.However, this correlation breaks down in Figure 3.3.2, which shows the relationship between predicted peak to peak transmission error and measured noise at a torque level of 140 Nm.The final conclusion is that it may not be possible to identify a single parameter, such as peak-to-peak transmission error, that can be directly related to measured noise and vibration.3.4 Paper D: Gearbox Noise and Vibration ?Influence of Bearing Preload The influence of bearing endplay or preload on gearbox noise and vibrations is investigated in Paper D.Measurements were carried out on a test gearbox consisting of a helical gear pair, shafts, tapered roller bearings, and a housing.Vibration measurements were carried out at torque levels of 140 Nm and 400 Nm with 0.15 mm and 0 mm bearing endplay and with 0.15 mm bearing preload.The results shows that the bearing endplay or preload influence gearbox vibrations.Compared with bearings

with endplay, preloaded bearings show an increase in vibrations at speeds over 2000 rpm and a decrease at speeds below 2000 rpm.Figure 3.4.1 is a typical result showing the influence of bearing preload on gearbox housing vibration.After the first measurement, the gearbox was not disassembled or removed from the test rig.Only the bearing preload/endplay was changed from 0 mm endplay/preload to 0.15 mm preload.Therefore the differences between the two measurements are solely due to different bearing preload.FE simulations performed by Sellgren and ?kerblom [6] show the same trend as the measurements here.For the test gearbox, it seems that bearing preload, compared with endplay, decreased the vibrations at speeds below 2000 rpm and increased vibrations at speeds over 2000 rpm, at least at a torque level of 140 Nm.3.5 Paper E: Gear Geometry for Reduced and Robust Transmission Error and Gearbox Noise In Paper E, gearbox noise is reduced by optimization of gear geometry for decreased transmission error.The optimization was not performed strictly mathematically.It was done 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 other important characteristics.Robustness with respect to gear deviations and varying torque was considered in order to find gear geometry with low transmission error in the appropriate torque range despite deviations from the nominal geometry due to manufacturing tolerances.Static and dynamic transmission error as well as noise and housing vibrations were measured.The correlation between dynamic transmission error, housing vibrations, and noise was investigated in a speed sweep from 500 to 2500 rpm at constant torque.No correlation was found between dynamic transmission error and noise.4 DISCUSSION AND CONCLUSIONS Static loaded transmission error seems to be strongly correlated to gearbox noise.Dynamic transmission error does not seem to be correlated to gearbox noise in speed

sweeps in these investigations.Henriksson [7] found a correlation between dynamic transmission error and gearbox noise when testing a truck gearbox at constant speed and different torque levels.The different test conditions, speed sweep versus constant speed, and the different complexity(a simple test gearbox versus a complete truck gearbox)may explain the different results regarding correlation between dynamic transmission error and gearbox noise.Bearing preload influences gearbox noise, but it is not possible to make any general statement as to whether preload is better than endplay.The answer depends on the frequency and other components in the complex dynamic system of gears, shafts, bearings, and housing.To minimize noise, the gearbox housing should be as rigid as possible.This was proposed by Rook [8], and his views are supported by the results relating to the optimization of a transmission housing described in section 2.5.Finite element analysis is a useful tool for optimizing gearbox housings.5 FUTURE RESEARCH It would be interesting to investigate the correlation between dynamic transmission error and gearbox noise for a complete wheel loader transmission.One challenge would be to measure transmission error as close as possible to the gears and to avoid resonances in the connection between gear and encoder.The dropbox gears in a typical wheel loader transmission are probably the gears that are most easily accessible for measurement using optical encoders.See Figure 5.1.1 for possible encoder positions.Modeling the transmission in more detail could be another challenge for future work.One approach could be to use a model of gears, shafts, and bearings using the transmission error as the excitation.This could be a finite element model or a multibody system model.The output from this model would be the forces at the bearing positions.The forces could be used to excite a finite element model of the housing.The housing model could be used to predict noise radiation, and/or vibration at the attachment points for the gearbox.This approach would give absolute values, not just relative levels.REFERENCES [1] Welbourn D.B., “Fundamental Knowledge of Gear Noise ??A Survey”, Proc.Noise & Vib.of Eng.and Trans., I Mech E., Cranfield, UK, July 1979, pp 9–14.[2] MackAldener M., “Tooth Interior Fatigue Fracture & Robustness of Gears”, Royal Institute of Technology, Doctoral Thesis, ISSN 1400-1179, Stockholm, 2001.[3] Ohio State University, LDP Load Distribution Program, Version 2.2.0, http://www.tmdps.cn/ , 2007.[4] Borner J., and Houser D.R., “Friction and Bending Moments as Gear Noise Excitations”,SAE Technical Paper 961816.[5] Oswald F.B.et al., “Influence of Gear Design on Gearbox Radiated Noise”, Gear Technology, pp 10–15, 1998.[6] Sellgren U., and ?kerblom M., “A Model-Based Design Study of Gearbox Induced Noise”, International Design Conference – Design 2004, May 18-21, Dubrovnik, 2004.[7] Henriksson M., “Analysis of Dynamic Transmission Error and Noise from a Two-stage Gearbox”, Licentiate Thesis, TRITA-AVE-2005:34 / ISSN-1651-7660, Stockholm, 2005.[8] Rook T., “Vibratory Power Flow Through Joints and Bearings with Application to Structural Elements and Gearboxes”, Doctoral Thesis, Ohio State University, 1995.