壳体设计规范.ppt

1、Introduction 介绍 Function Overview 功能概述 Gearbox Types 壳体类型 Design Guidelines 设计指南 Gears & Shafts, Bearings, Fasteners, Flanges, Flange Sealing, Ribs, Joints, Radii, Wall thickness, Corrosion, Surface treatment, NVH 齿轮、轴，轴承、紧固件、凸缘、凸缘密封、筋、过渡连接，倒圆角，壁厚，腐蚀，表面处理、噪音 Materials Options 材料选择 Material Weight 材料

2、重量 Suitable Casting Options 铸造类型 Sand Casting 砂型铸造 Gravity Die重力铸造,Die Casting压铸 Low Pressure低压 High Pressure高压 Casting Tolerance Comparison铸造公差比较 Material Comparison材料比较 Heat Treatment - Comparison热处理-比较 Material Machinability材料可加工性能 Typical Transmission case materials 传统变速箱壳体材料 Pro/E Casing Modell

3、ing Process Pro / E的建模过程 Typical Design Process典型的设计过程 Casing Design - Summary外壳设计 - 总结 Case Study Mg vs Aluminium 案例分析-镁合金与铝合金比较,The aim of this guide is to help the designer to make an informed choice when designing a transmission case or casings. The choices taken will depend on many factors such

4、 as:本指南的目的是帮助设计人员在设计变速箱外壳时，作出正确的选择。需要考虑的因素如下：,Time时间 Available time to design and or manufacture 设计和制造所用时间 Cost成本 Cost Targets (Of design, Materials,Manufacturing and Processes) 成本目标（设计，材料，制造） Number of units 组件数量 Small, medium of large volumes 小件，中件，大件 Function功能 Structural, Non structural, Loaded

5、vs Non- Loaded 结构性或者非结构性功能，承载或者非承载结构,Size尺寸 Overall size of transmission, Castability, Machinability, 变速器外形尺寸，铸造性能，机械加工性能 Complexity 复杂性 Influenced by Size and Function compromised by Castability / machinability 受尺寸、功能、铸造性能/可加工性的影响 Material材料 Iron, Aluminum or Magnesium Alloys 铁，铝合金或镁合金,Environment

6、环境 External Regime, package as well as recyclability of materials 外部政策，包装以及材料可回收性 Duty 工况 Life, Duty Cycle, Load regime, Torque and Power 路谱，负载，扭矩和动力 Weight重量 Target Vehicle weight, Transmission target weight see materials 目标车辆的重量，变速箱的目标重量-由变速箱材料决定 Vehicle Type车辆类型 Transverse, Longitudinal, FWD, RWD

7、, 2WD,4WD 横置，纵置，前轮驱动，后轮驱动，两轮驱动， 四轮驱动,To provide a suitable housing so that speed and torque can be transmitted from the input via shafts, gears or pulleys to the output. These speeds and torques can be 一个结构合理的壳体，可以使速度和扭矩从发动机经过输入轴，齿轮或滑套传到输出轴。使速度和扭矩达到如下变化： Continuous 连续 Stepped 阶梯 Constantly changing

8、不断变化的 Speeds and torques impart loads as a result of the gears, shaft and differentials. The housing react these loads and forces 齿轮，轴和差速器的速度和转矩最终以力的形式作用到壳体,Provide an Oil reservoir for cooling and lubrication 为变速箱冷却和润滑提供油路系统 In addition mount or support other sub systems such as为其他子系统提供安装支撑，如下： Dri

9、ve Clutches 驱动离合器 CSC Engine Starter Motors 发动机起动马达 Manual Shifter Systems 手动换档系统 Shift mechanisms, Rails & Forks, Cable Brackets 换挡机构、手柄、拨叉、拉线支架 Hydraulic Shifter Systems 液压换挡系统 Automated Manual Shift Mechanisms 自动换挡系统 Wet Clutches Powershift etc Pumps,Accumulators, Coolers, Filters etc 湿式离合器 - 动力换

10、档原件，如泵，蓄能器，冷却器，过滤器等 Park Brakes 驻车制动,Depending on the type of Loads and installation casings can be divided into two types: 根据载荷的不同，可将壳体分为两类： Non Structural the loads the casing sees are from the shafts and gears only with the casing hanging off the engine and the vehicle side member 非结构性壳体-齿轮和轴作用到壳

11、体上的作用力最后作用到发动机和车辆侧梁 private vehicles 乘用车 commercial vehicles 商用车 Structural 结构性壳体 Tractor chassis- Transaxles 牵引车底盘-驱动桥 The transmission case is an integral part of the chassis. 变速箱是底盘的一个组成部分 Motor-sport applications 赛车的应用 Transaxle designs Vehicle loads going through the casing such as Tractor Tran

12、saxle suspension hard points located on them. 驱动桥设计 - 车辆荷载通过变速箱壳体悬置部位传递到它们,Non Structural,Motor-sport Transaxle,Tractor Transaxle牵引车驱动桥,These are the main components for transferring speed and torque in a transmission 在变速箱结构中，这些是用于传递速度和扭矩主要组件。 As a result they impart the following type of loads on t

13、he casing 齿轮和轴从下面几个方面影响作用到壳体上的作用力： Separating Loads are effectively trying to push the each shaft and gear apart. 分离载荷（径向力）有效地将每个轴和齿轮推开。 Tangential Loads act normal to the base circle are a result of the gears reacting against each other. 垂直于基圆的切向力是齿轮之间相互作用的结果 Axial Loads act along the rotating axis

14、 of the gear and shaft. 轴向载荷沿齿轮和轴的轴向传递。 Helical gears over spur gears will result in having to consider axial load effects.The larger the helix angle the larger the load. Other gear forms that impart axial loads include bevel and hypoid gearing 斜齿轮与直齿轮相比，必须考虑轴向载荷的影响。螺旋角越大轴向载荷越大。锥齿轮和准双曲面齿轮也必须考虑轴线载荷的影

15、响,The bearings are the elements that actually interact with the casing. It is here that the gearing loads pass through the rolling elements into the casing. The size and type are very much dependant on the loads anticipated as well as the layout of the rotating parts within it. 轴承是直接与外壳相互作用的元件。齿轮力最终

16、通过轴承内部的旋转件传递到外壳。轴承尺寸和类型的选择依赖于受力大小以及内部旋转件的布局。 Deep Groove Ball - 深沟球轴承 Cylindrical Roller圆柱滚子轴承 Taper Roller圆锥滚子轴承 The seating / mounting of the bearings in the casings needs careful consideration 壳体轴承的安装需要进行充分的考虑 Bore 轴承孔 This will ensure that the bearing retains it shape when loaded 这将确保轴承在受力时形状保持不

17、变。,Needs to be manufactured to tight tolerances to ensure the bore is round and concentric to the shaft axis. 需要严格按照公差加工，以确保该孔的圆度并且于轴的轴线同心。 The amount of interference / clearance depends on the type of bearing and load 轴承与轴承孔之间的配合间隙取决于轴承类型和轴承力 Typical transmission applications the outer race is held

18、 in the casing with a interference fit. 传统的变速箱应用，轴承外圈与壳体采用过盈配合 For bearings that require some adjustment during build a transition fit can be employed. 一些需要调整的轴承，一般采用过度配合。 General recommendations 一般建议 Aluminum - 0.001mm of interference per mm of diameter. 铝合金壳-直径方向每毫米过盈量为0.001mm Magnesium - 0.0015mm

19、 of interference per mm of diameter. 镁合金壳-直径方向每毫米过盈量为0.0015mm,Abutment止口 This diameter should conform to bearing manufacturers recommendations. In addition the radii (or undercut) between the abutment and bore should be also as per bearing manufacturers recommendations else the bearing will not seat

20、 correctly and influence any preload values. 该直径应符合轴承制造商的建议。此外，轴承挡圈与轴承孔之间的倒圆角，应该也是按照轴承制造商建议，否则轴承将不能正确安装和影响轴承作用到壳体上力的分布。 Extraction 拆卸 Suitable consideration should be given to bearing (full or part such as outer race) extraction.This could take the form of slots in the abutment face to allow a pulli

21、ng tool. 适当考虑轴承（全部或部分，如外圈）的拆卸。可以采取在接触面增加槽的方式来允许拆卸工具将轴承拆除。 Bearing Cages轴承保持架 In the case of taper roller bearings provision for bearing cage clearance may be required 在使用圆锥滚子轴承的情况下， 可能需要考虑轴承保持架的间隙。,Lubrication 润滑 The bearing will require adequate oil flow to ensure correct operation as well as cooli

22、ng to extend the bearings life. 为提高轴承寿命，轴承将需要足够的润滑油，以确保正常的工作，以及冷却。 Suitable galleries or slots to allow the oil to enter the bearing need to be designed.设计时，需要设计合理的油槽或者油道，以保证润滑油能够对轴承进行润滑。 Too many or positioned in the wrong place relative to the separation loads can lead to a reduction in both the c

23、asing and bearing stiffness. 油道或油槽布置不合理会产生相应的分离力，从而降低壳体和轴承的刚度,Two similar approaches to directing oil to bearings (Also up the shaft center drilling) 两种相似的润滑轴承的方法（轴中心钻孔也可以）, Fasteners in this case refers to mounting of casings halves or covers using threaded bolts and screws 用于连接变速箱壳体的紧固件包括螺栓和螺钉。 Th

24、e fasteners ensure when properly loaded that the joint face integrity is not impeded and therefore maintain the transmissions oil carrying capacity. 当变速箱传递扭矩时，连接螺栓确保壳体连接面不分离，从而保证连接面的密封性能。 To do this a suitable number of fasteners correctly spaced and sized having the correct torque applied will ensu

25、re this.,为了满足以上要求，必须正确的布置紧固件的数量，选择合适大小的紧固件以及预紧扭矩。 However a few rules should be employed to help. For tapping and drill depths refer the existing Ricardo Guidelines. 可以根据一些简单规则来选择紧固件。根据现有的里卡多手册来确定攻丝和钻孔的深度。 Spacing between bolts will determine the contact patch between the two casing halves around th

26、e flange ensuring a good seal. as a rule of thumb should be no greater than 8 x Bolt 螺栓间的间隔将决定两壳体接触面间的密封性能。作为一个经验法则，螺栓间距不大于8*螺栓直径。,Source Ricardo Fastener Guidelines Extract Only,螺纹孔尺寸-粗牙,Clearances for tightening the fastener should be considered. Typical methods include 必须考虑紧固件工具的安装空间。典型的安装方法包括： s

27、panners, open, and ring 呆扳手、梅花扳手 power operated tools with socket driving tools. 使用套头的电动工具 Bolt patterns with a high number bolts as well as being built in high volumes will use the latter therefore full consideration should be given to these tools and there preferred clearances. 将来，会出现很多在体积大的结构上装配很

28、多螺栓的情况，因此必须考虑在这种情况下，安装工具所需的安装间隙。,对于六角头紧固件安装间距要求,Source Ricardo Fastener Guidelines,1.5 2 x D,Not Recommended 不建议,Al 1 x D Mg - 1.125xD,Al-1xD Mg 1.125xD,D,Flange Joints 凸缘连接 Flange joint stiffness will ensure the fasteners will do their job correctly 凸缘连接处刚度将确保紧固件正确地完成他们的工作 Mg Specific 镁合金的特别要求 Allo

29、w for the lower modulus compressive property.允许较低的抗压模量属性 Use large fillets可以使用大倒角 Avoid tapping breaking through boss 通过凸台避免攻丝破坏 Smooth transition of form 过度形式平稳 Make flanges 50% Cast Iron Bolt Patterns Compared to Cast Iron 与铸铁相比螺栓的要求 Smaller Bolts小螺栓 Half the spacing间距减,Different Arrangements for

30、improving flange stiffness without adding more material 在不增加材料的前提下，提高凸缘强度的不同方法,Pull Direction拔模方向,6mm Min Land width for sealant 为了密封，宽度最小为6mm,O Ring arrangement O型密封圈结构 Good sealing solution low volume only 降低结构体积的同时提高密封性 Motorsport typical application赛车的典型应用,Caution O Ring can expand and extrude 注

31、意-O型密封圈可能被挤压变形 To Overcome this Some applications use a trapezoid shaped groove 为了克服这种情况，使用梯形沟槽, Ricardo plc 2006,Cast 45 x 2 or Radius Chamfer Ensures beading of Silicon sealant沿半径方向45倒角确保硅密封胶密封良好 Prevents contamination of gearbox 防止污染变速箱,Not Recommended 不推荐,Joint of unequal section 变截面过渡连接,连接端面与主体

32、的筋一般在过渡处有过渡角,Unprotected Aluminium & magnesium is more resistant to atmosphere than mild stee 没有采取保护措施的情况下，铝和镁比低碳钢更不容易生锈 Corrosion resistance decreases slightly as wall thickness increases 随着壁厚的增加，壳体耐腐蚀性略有降低 Galvanic corrosion between dissimilar materials e.g steel and magnesium 考虑异性材料间的电偶腐蚀，例如钢铁和镁

33、Good design can reduce the effects 好的设计能够减少以下影响 Ensuring adequate drainage 确保合理的排水 Washer/spacer to prevent direct contact between dissimilar materials 在异性材料之间增加垫片/间隙，防止的直接接触 Bolt head design 螺栓头设计 Good casting design to prevent dust and water accumulation 好的壳体设计能够防止灰尘和水分积聚 Use of surface treatments

34、 on Transmission Casings 表面处理工艺被用在变速箱壳体设计中 None for automotive Underbonnet applications Also the case for magnesium applications 镁合金变速箱使用该工艺 Painting civil aircraft 喷漆-民用飞机 Hard anodising military aircraft 硬质阳极氧化- 军用飞机 Keronite,GOOD DESIGN 好的设计,BAD DESIGN 不好的设计,Electrolyte Accumulation 电解质积累,Effecti

35、ve Drainage 有效的排水,Example : Steel Washer & Mg Casing,Example : Use a Hard anodised aluminium washer with Mg Casings 在镁合金壳体上使用硬质阳极氧化铝垫圈,Painting Civil Aviation 喷漆-民航 Recommended minimum protection 推荐最低保护措施 Preceded by a chromate conversion coating to act as a key for the paint 由铬酸盐转化为涂层这个过程是喷漆 工艺的关键

36、Hard anodise Military Aviation硬质阳极氧化- 军用航空 Forms thick abrasion resistant coating 表面形成厚的耐磨涂料 Inherent porosity requiring sealing to form a duplex film 形成双面膜提高固有孔隙的密封性 Keronite Produces a hard ceramic layer preliminary for magnesium 在镁的表面产生一层坚硬的陶瓷层 Increases abrasive wear resistance - 增加耐磨性 Provides

37、corrosion protection- 提供防腐蚀保护 Reduces fatigue strength of treated alloy less than hard anodising 降低合金处理时的疲劳强度 -比硬阳极氧化低,Transmission noise 变速箱噪音 Result of Transmission Errors 变速箱设计错误所致 Shaft Stiffness 轴刚度 Gear Micro Geometry 齿轮微观几何 Housing Flex 壳体柔性 Poor Housing design Can Magnify these errors 壳体的错误设

38、计可以放大这些错误 Large flat areas on casings can flex壳体上大面积平面区域增大壳体柔性 Change the frequency of these panels by 通过一下方式改变平面固有频率 Ribs 筋 Step 阶梯特征,Stepped surface,Cast Iron Gray灰铸铁 Advantages优点 Cheapest Castable material价格便宜 Good Castability良好的铸造性能 Strength强度 Very Large Castings possible可铸造超大型铸件 Thermal Expansi

39、on similar to steel热膨胀性跟钢类似 Disadvantages缺点 Weight重量 Machinability of Hard outer skin外表面的可加工能力 Aluminium Alloy 铝合金 Advantages over Iron 相比铸铁的优势 Many Casting Techniques available铸造工艺多样性 Sand砂型铸造,Gravity Die重力铸造 Low Pressure Die低压铸造 High Pressure Die高压铸造 Heat Treatable to improve properties通过热处理来提高毛坯性

40、能 High resistance to shock loading高耐冲击性能 Machinability加工性能 Good Corrosion resistance 良好的耐腐蚀性 Disadvantages Over Iron- 相对于铸铁的缺点 Thermal expansion needs to be accounted for when supporting gears and shaft需要考虑热膨胀对齿轮和轴孔的影响 Magnesium Alloy 镁合金 Advantages Over Aluminium 相对于铝合金的优点 Strength to Weight Ratio强

41、度重量比 Machinablity V Good 加工性能良好 Damping Ability阻尼能力, Excellent Die Casting Properties 卓越的压铸性能 Thin Wall sections Possible 壁可以更薄 Extended Die Life 模具寿命更长 Faster Material Flow材料流动性能更好 Higher Pressures possible压力可以更高 Disadvantages Over Aluminium- 相对于铝合金的缺点 Low elastic modulus弹性模量低 High notch sensitivit

42、y缺口敏感性高 Low hardness硬度低 Corrosion hazard potential 潜在的腐蚀危险 Recycle ability回收能力,Materials-Why Weight 材料-重量因素, Why Weight is an issue in transmission casings 为什么在变速箱壳体设计时需考虑重量因素 Cost 成本 Reduced weight is reduced material cost 降低重量就是在降低成本 To reduce overall vehicle weight 降低整车重量 Improvements in vehicle

43、performance提高整车如下性能 Acceleration加速性能 Emissions排放 Fuel consumption燃油经济性, Improvements in safety提高安全性能 Braking effort制动性能 Crash energy碰撞能量,获得同样载荷时体积质量对比,Suitable Casting ProcessSand Casting 铸造工艺砂型铸造, Sand Casting砂型铸造 The pouring of molten metal into a Sand Mould熔融金属的浇注到一个砂型 Advantages优点 Low Equipment

44、Cost- 设备成本低 Largest Size of Castings possible- 可铸造尺寸较大铸件 Suited to Complex Shapes and Cores- 适用于形状复杂的件 Very Low gas porosity possible-气密性好 Versatile- 多功能,Suitable Casting ProcessSand Casting 铸造工艺砂型铸造, Disadvantages缺点 Wall Thickness limitations- 壁厚有一定限制 Poor Linear Tolerance 4mm/m- 铸造公差难以保证，4毫米/米 Rou

45、gh Surface Finish 6.5-12.5 microns-表面粗糙，粗糙度为6.5-12.5微米 Coarser Grain Size than permanent Mould castings- 表面颗粒比金属型铸造大,Suitable Casting ProcessGravity Die Casting铸造工艺重力铸造, Gravity Die Casting重力铸造 The pouring of molten metal into a Permanent mould under gravity or low pressure在重力或低压的作用下将熔融金属的压入金属性模具中 A

46、dvantages优点 Low Cost than Die casting- 比压铸成本低 Higher Casting Rate than Sand- 比砂铸铸造效率高 Finer grain size 更高的表面质量 High Quality Castings -铸件质量更好 Less finishing & polishing required - 表面抛光要求低,Suitable Casting ProcessGravity Die Casting铸造工艺重力铸造, Disadvantages缺点 Wall Thickness limitations depending on Mate

47、rial 壁厚受材料限制 Linear Tolerance 3mm/m- 铸造公差为3毫米/米 Surface Finish 4-10 microns- 表面粗糙度为4-10微米 Limited complexity- 壳体结构不能太复杂,Suitable Casting ProcessGravity Die Casting铸造工艺重力铸造, Low Pressure Die Casting低压铸造 A Repetitive casting process by injecting molten metal under low pressure into a metal die. The ga

48、s pressure holds the metal in the die until it solidifies 在低压作用下将熔融金属注入到金属模中。压力一直保持至金属凝固。 Advantages优点 30 castings an hour possible 一小时可铸造30件 Thin walls thickness possible 2-3mm 壁厚可做到2-3毫米,Suitable Casting ProcessGravity Die Casting铸造工艺重力铸造, Best Linear Tolerances 2.5mm/m尺寸公差达2.5mm/m Best Surface fi

49、nish e.g. 3microns最佳表面粗糙度可达到3微米 High Yields 90-98% as runners andrisers excluded 成品率可达到90-98 Reduced fettling and trimming减少模具修补与保养 Pore-free castings obtainable铸件致密性更好，内部无缩松 Directional solidification of castings advantageous有利于铸件的定向凝固,Suitable Casting ProcessGravity Die Casting铸造工艺重力铸造, Riser tube

50、 draws metal from below the dross layer avoiding inclusion entrapment 金属液经压力管从下压入模具，避免浮杂夹杂在铸件内部 Sand cores may be used. Complex casting shapes are possible通过砂芯的使用，可以铸造形状复杂的铸件 Die costs are low, cast iron or steel dies are used 模具成本低，模具材料可采用铸铁或钢 Can fully heat treat castings铸件可进行热处理,Suitable Casting

51、ProcessGravity Die Casting铸造工艺重力铸造, Disadvantages缺点 Size of castings limited by machine size铸件的尺寸受压铸机尺寸限制 Sound thick sections are difficult to cast尺寸厚的部位难以成型 Surface finish between that of gravity die and high pressure表面粗糙度介于重力铸造和高压铸造之间 Wall thickness not as thin as high pressure but better than gr

52、avity die壁厚不是压力越高壁厚越薄，但比重力铸造会好一些,Suitable Casting ProcessGravity Die Casting铸造工艺重力铸造, High Pressure Die Casting 高压铸造 A Repetitive casting process by injecting molten metal under pressure eg 1000psi into a metal die 通过高压例如1000PSI将熔融金属压入到金属模具中。 Advantages优点 200 castings an hour possible一个小时可铸造200件 Thi

53、n walls thickness possible 1-2.5mm壁厚可达到1-2.5mm Best Linear Tolerances 2mm/m最佳表面粗糙度可达到1.5microns,Suitable Casting ProcessGravity Die Casting铸造工艺重力铸造, Very fine surface grain size非常精细的表面晶粒尺寸 High strength in the as cast condition铸态强度高 Tolerances and repeatable properties obtained 公差精度高和模具寿命高 Castings may be quenched铸件可淬火,Suitable Casting ProcessGravity Die Casting铸造工艺重力铸造, Disadvantages缺点 Size of castings limited by machine size铸件的尺寸受压铸机尺寸限制 Sound thick sections are difficult to cast尺寸厚的部位难以成型 Castings may suffer from porosity铸件可