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XI
本科毕业设计（论文）
桥式起重机设计
摘要：
建国以来，我国起重机械行业在产品设计、生产和科学研究方面取得了很大的成绩，积累了不少的经验，为了总结这些经验，提高生产效率，以适应国民经济日益发展的需要，制造行业中对桥式起重机的各方面的要求越来越高。
本设计要完成了桥式起重机主体结构部分的设计及主梁和端梁的校核计算。
采用正轨箱形梁桥架，正轨箱形梁桥架由两根主梁和端梁构成。
主梁外侧分别设有走台，并与端梁通过连接板焊接在一起形成刚性结构。
为了运输方便在端梁中间设有接头，通过连接板和角钢使用螺栓连接，这种结构运输方便、安装容易。
小车轨道固定于主梁的压板上，压板焊接在盖板的中央。
本设计正确选择了起重机桥架钢结构构造形式和构件截面，以保证其在使用过程中的强度、刚度和稳定性。
设计时，同时还注意了起重机的结构制造工艺性、省料、安装以及维修方便等问题，使大车运行和起升机构能够工作中得到更好的安全和使用性能保证。
关键词：
桥式起重机；大车运行机构；主梁
Bridge-typehoistcrane
Abstract:
sincethefoundingofnewChina,China'scraneindustryinproductdesign,productionandscientificresearchhasmadegreatachievement,accumulatedalotofexperience,inordertosumuptheseexperience,improveproductionefficiency,tomeetthegrowingneedsofthedevelopmentofnationaleconomy,manufacturingindustryofbridgecraneinthevariousaspectsofincreasinglyhighdemand.
thisdesigntocompletethebridgecranemainstructuredesignandcalculationofmaingirderandendgirder.Thetrackboxgirderbridge,trackboxgirderbridgeconsistsoftwomainbeamsandsidebeams.Mainbeamarerespectivelyarrangedoutsidetheplatform,andwiththeendbeamthroughaconnectingplateareweldedtogethertoformarigidstructure.Inordertoconvenienttransportationintheendbeamisarrangedinthemiddleofajoint,throughtheconnectionplateandtheanglesteelboltconnectionstructure,theconvenienttransportation,easyinstallation.Trolleyrailisfixedonthemainbeamoftheplaten,platenweldingintheflatcentral.
Thedesigncorrectselectionofcranesteelstructureformandcomponentsection,inordertoensureitsuseintheprocessofstrength,stiffnessandstability.Thedesign,butalsopayattentiontothecranestructuremanufacturingprocess,materialsaving,convenientinstallationandrepairwaitforaproblem,maketheengineoperationandthehoistmechanismcanworktogetbettersafetyandperformanceguarantee.
Keywords:
crane;cranetravelingmechanism;girder
目录
摘要···························································I
ABSTRACT····················································II
1．绪论·························································1
1.1桥式起重机的概述············································1
1.2桥式起重机的综述和原理·····································1
1.3起重机国内外发展情况········································2
1.3.1国外起重机制造业发展趋势································2
1.3.2国内起重机存在的问题····································3
1.4双梁桥式起重机研究的意义·································4
2．大车运行机构方案拟定及选择···································5
2.1大车运行机构的可供选择的几种常用方案·······················5
2.1.1低速集中驱动···········································5
2.1.2中速集中驱动···········································6
2.1.3高速集中驱动···········································6
2.1.4分别驱动···············································7
2.2大车运行机构的几种方案······································7
2.2.1低速集中驱动···········································7
2.2.2中速集中驱动···········································7
2.2.3高速集中驱动···········································8
2.2.4分别驱动···············································8
2.3大车运行机构方案的选择······································8
3.大车运行机构的设计···········································9
3.1运行阻力的计算·············································9
3.1.1摩擦阻力············································9
3.1.2坡道阻力············································11
3.1.3风阻力·············································11
3.2电动机的选择···············································12
3.2.1概述··················································123.2.2电动机静功率···········································13
3.2.3电动机初选···········································13
3.2.4电动机过载校验········································14
3.2.5电动机发热校验········································153.2.6起动时间与起动平均加速度校验···························15
3.2.7选择合适的电动机型号···································17
3.3减速器的选择··············································173.3.1概述··················································17
3.3.2总体设计···············································17
3.3.3确定传动比·············································18
3.3.4计算传动装置的传动参数·································183.3.5齿轮的设计·············································193.3.6齿轮的强度结构设计·····································193.3.7齿轮的几何尺寸计算······································213.3.8低速轴设计·············································21
3.3.9轴的结构设计···········································22
3.3.10轴上的载荷············································24
3.3.11校核轴承的寿命强度验算································24
3.3.12按弯矩合成应力校核轴的强度····························25
3.3.13减速器型号的选择······································25
3.4制动器的选择··············································26
3.4.1制动器概述·············································26
3.4.2制动器相关参数的计算···································26
3.4.3制动器型号的选择·······································28
3.5联轴器的选择··············································28
3.6运行打滑验算··············································29
4.主梁方案的拟定及选择·········································30
4.1主梁可供选择的几种方案····································30
4.1.1工字钢主梁············································30
4.1.2桁架主梁··············································30
4.1.3箱形主梁··············································31
4.2主梁方案分析··············································32
4.2.1工字钢主梁············································32
4.2.2桁架主梁··············································32
4.2.3箱形主梁··············································32
4.3主梁方案选择···············································33
5.主梁的设计及优化·············································33
5.1主梁设计要求简介··········································34
5.2主梁跨度的确定············································34
5.3主梁上钢轨的选择··········································35
5.4主梁的合理强度设计········································35
5.4.1梁的强度条件··········································35
5.4.2梁的合理截面形状······································37
5.4.3变截面梁与等强度梁····································38
5.4.4梁的合理受力·········································38
5.5主梁合理刚度设计··········································39
5.5.1梁的刚度条件··········································39
5.5.2梁的合理刚度设计·····································39
6.结论··························································42
致谢························································43
参考文献·························································44
西南科技大学本科生毕业论文
1绪论
1.1桥式起重机的概述
桥式起重机是横架于车间、仓库和料场上空进行物料吊运的起重设备。
由于它的两端坐落在高大的水泥柱或者金属支架上，形状似桥，所以又称“天车”或者“行车”。
桥式起重机的桥架沿铺设在两侧高架上的轨道纵向运行，起重小车沿铺设在桥架上的轨道横向运行，构成一矩形的工作范围，就可以充分利用桥架下面的空间吊运物料，不受地面设备的阻碍。
它是使用范围最广、数量最多的起重机械。
1.2桥式起重机的综述和原理
桥式起重机可分为普通桥式起重机、简易梁桥式起重机和冶金专用桥式起重机三种。
普通桥式起重机一般由起重小车、桥架运行机构、桥架金属结构组成。
起重小车又由起升机构、小车运行机构和小车架三部分组成。
起升机构包括电动机、制动器、减速器、卷筒和滑轮组。
电动机通过减速器，带动卷筒转动，使钢丝绳绕上卷筒或从卷筒放下，以升降重物。
小车架是支托和安装起升机构和小车运行机构等部件的机架，通常为焊接结构。
起重机运行机构的驱动方式可分为两大类：
一类为集中驱动，即用一台电动机带动长传动轴驱动两边的主动车轮；另一类为分别驱动、即两边的主动车轮各用一台电动机驱动。
中、小型桥式起重机较多采用制动器、减速器和电动机组合成一体的“三合一”驱动方式，大起重量的普通桥式起重机为便于安装和调整，驱动装置常采用万向联轴器。
起重机运行机构一般只用四个主动和从动车轮，如果起重量很大，常用增加车轮的办法来降低轮压。
当车轮超过四个时，必须采用铰接均衡车架装置，使起重机的载荷均匀地分布在各车轮上。
桥架的金属结构由主梁和端梁组成，分为单主梁桥架和双梁桥架两类。
单主梁桥架由单根主梁和位于跨度两边的端梁组成，双梁桥架由两根主梁和端梁组成。
主梁与端梁刚性连接，端梁两端装有车轮，用以支承桥架在高架上运行。
主梁上焊有轨道，供起重小车运行。
桥架主梁的结构类型较多比较典型的有箱形结构、四桁架结构和空腹桁架结构。
箱形结构又可分为正轨箱形双梁、偏轨箱形双梁、偏轨箱形单主梁等几种。
正轨箱形双梁是广泛采用的一种基本形式，主梁由上、下翼缘板和两侧的垂直腹板组成，小车钢轨布置在上翼缘板的中心线上，它的结构简单，制造方便，适于成批生产，但自重较大。
偏轨箱形双梁和偏轨箱形单主梁的截面都是由上、下翼缘板和不等厚的主副腹板组成，小车钢轨布置在主腹板上方，箱体内的短加劲板可以省去，其中偏轨箱形单主梁是由一根宽翼缘箱形主梁代替两根主梁，自重较小，但制造较复杂。
四桁架式结构由四片平面桁架组合成封闭型空间结构，在上水平桁架表面一般铺有走台板，自重轻，刚度大，但与其他结构相比，外形尺寸大，制造较复杂，疲劳强度较低，已较少生产。
空腹桁架结构类似偏轨箱形主梁，由四片钢板组成一封闭结构，除主腹板为实腹工字形梁外，其余三片钢板上按照设计要求切割成许多窗口，形成一个无斜杆的空腹桁架，在上、下水平桁架表面铺有走台板，起重机运行机构及电气设备装在桥架内部，自重较轻，整体刚度大，这在中国是较为广泛采用的一种型式。
普通桥式起重机主要采用电力驱动，一般是在司机室内操纵，也有远距离控制的。
起重量可达五百吨，跨度可达60米。
1.3起重机国内外发展情况
1.3.1国外起重机制造业的发展趋势
近年来，随着电子计算机的广泛应用，许多国外起重机制造商从应用计算机辅助设计系统（CAD），提高到应用计算机进行起重机的模块化设计。
根据市场调查预测的统计数字和积5累的资料、图表、图线规律，在严密的科学理论指导下，拟定起重机结构、机构、部件等多层次的标准化、模块化单元。
起重机采用模块单元化设计，不仅是一种设计方法的改革，而且将影响整个起重机行业的技术、生产和管理水平，老产品的更新换代、新产品的研制速度都将大大加快。
对起重机的改进，只需针对几个需要修改的模块；设计新的起重机只需选用不同的模块重新进行组合；提高了通用化程度，可使单件小批量的产品改换成相对批量的模块生产。
亦能以较少的模块形式，组合成不同功能和不同规格的起重机，满足市场的需求，增加竞争能力。
1.3.2国内起重机存在的问题
起重机制造厂家要按用户的要求承担特殊的设计，即包括起重机的所有部件和起升高度、所必须移动物料的距离等，在厂房建好前，就必须将厂房建筑蓝图或厂房的主要尺寸提供给起重机制造厂家，设计者按用户的要求，设计起重机的外形及确定其主要参数，用户确认后，才开始设计制造。
从这个过程，国内起重机制造厂与国外工业发达国家有很多相似之处。
但目前国内起重机行业存在的问题已严重阻碍着自身的发展。
（1）设计手段不完善、工艺水平较低
长期以来，利用图板手工设计制图，需要较长的设计周期。
虽然CAD技术在国内起重机行业得到广泛的作用，但应用水平却参差不齐，关键问题是由于“设计”上的差异。
国内一些应用水平较高的部门已真正做到了计算机辅助设计，而还有相当一部分用户仍停留在传统型CAD应用系统上，对一些重大非标准起重机产品设计，设计是在设计人员的头脑中完成，再利用计算机实现几何信息的处理，把CAD技术作为一种绘图、描图的工具。
对于起重机CAD的二次开发，如起重机方案设计和起重机械零部件辅助工艺规程设计还未完善。
起重机方案图设计，只是把预先设计外形尺寸及主要参数输入到计算机内，显示并打印出所需起重机的总图，计算机不能对主要受力点的应力进行分析，不能进行设计计算和标准部件的选择。
一些起重机厂家，对成系列、成批量的通用起重机产品（如5～50t双梁桥式起重机），为了降低成本，简化生产管理，通用化设计也只能做到对车轮组、滑轮组、卷筒组和联轴器的通用化设计，对于运行机构、小车架，仍只能按不同起重量设计，桥架端梁则按不同起重量，不同小车轨距多款设计，对桥式起重机的设计不能使整机与机构、机构与部件、部件与零件之间的参数匹配。
国内企业，普遍缺乏生产技术，工艺水平较低，一些起重机生产企业的工装设备、装配及检测手段比较落后，油漆及焊接工艺不过关，严重影响了起重机的质量。
（2）专业化协作水平较低
我国专业化协作目前只做到20%，80%仍靠企业自己设计、制造。
一台起重机中只有电动机、减速器、制动器及一些电气元件可外购，其它铆焊件、机加工件、台主梁、车轮组、端梁、小车架仍靠企业自行设计，这样需花费大量的时间，影响了起重机的生产周期。
（3）交货期长
由于设计及工艺原因，我们制作的非标准起重机交货期为4～6个月，是国外企业的2倍左右。
这远远不能适应市场经济竞争的要求，使企业失掉了不少机遇。
1.4双梁桥式起重机研究的意义
随着现代工业的迅速发展，电子计算机的广泛应用，系统工程、优化工程、创造性工程、人机工程等现代化理论的发展，大大加快了现代工业的发展进程，使社会生产力又跃上了一个新水平。
当今世界工业生产，由于市场竞争的需要，生产方式由单一品种的大批量向着多品种的变批量方向发展。
30年代以来，物料搬运技术仅指的是各类起重运输设备，而90年代的物料搬运系统逐渐增加了许多自动化内容，包括自动识别、自动导向、自动计数、自动称重等。
为了使生产和流动能够紧密配合，构成更
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