郑州大学机械设计基础第三版课后作业答案

郑州大学机械设计基础第三版课后作业答案（通用3篇）

篇1：郑州大学机械设计基础第三版课后作业答案

本文只解答了简答题部分，计算题部分因需作图和一些公式，书写较慢，故省略，请见谅！

5-1什么叫主轴回转误差？它包括哪些方面?

（1）主轴回转误差——在主轴运转的情况下，轴心线位置的变动量叫主轴回转误差。

（2）包括：1纯轴向窜动△x。2纯径向移动△r。3纯角度摆动△Y

5-2在卧式镗床上采用工件送进方式加工直径200mm的通孔时，若刀杆与送进方向…

35-4什么是误差复映？误差复映系数的大小与那些因素有关？

毛坯的误差部分或全部复映到工件上的现象为误差复映。

误差复映系数E=△I/△毛=C/K系统，K系统越大，E就越小，毛坯误差复映到工件上的部分就越小。5-8中间深度较两端浅是因为机床刚度有限，工件变形在中间严重造成。比调整深度小时因为刀架刚度有限，加工时刀架变形收缩。

5-13原因：垫圈、螺母压紧过大，夹紧后使工件在轴线上变形膨胀，加工完成后，卸下夹紧力，工件变形消失，故导致加工不精确，产生壁厚不均匀的误差。

5-15（1）服从偏态分布的误差：有随机误差和突出变值误差的系统服从偏态误差。如端面圆跳动，径向圆跳动等。（2）服从正态分布的误差：大批大量生产，工件的尺寸误差是由很多相互独立的随机误差综合作用的结果，且没有一个随机误差是起决定作用的。如调整好的机床加工好的一批零件。

5-19工艺系统不稳定。

5-20为什么机器零件一般都是从表面层开始破坏？

零件表面和表面层经过常规机械加工或特种加工后总是存在一定程度是微观不平度、冷作硬化、残余应力以及金相组织变化等问题，零件在高应力、高速度、高温等条件下工作时，由于表面作用着最大的应力并直接受外界介质的腐蚀，表面层的任何缺陷都可能引起应力集中，应力腐蚀等现象，从而机器零件一般是从表面层开始破坏。

5-21试述表面粗糙度，表面物理机械性能对机器使用性能的影响。

（1）表面粗糙度对机器使用性能的影响：a对耐磨性，一般表面粗糙度越大，耐磨性越差，但表面粗糙度太小耐磨性也差；b对疲劳强度，表面粗糙度越小，使疲劳强度升高；c对配合质量：表面粗糙度太大，影响配合稳定性；d对抗腐蚀性，表面粗糙度越小，抗腐蚀性越好。

（2）表面层物理机械性能对机器使用性能的影响：a金相组织变化使耐磨性改变；b残余压应力可以提高零件的疲劳强度，而残余拉应力会降低疲劳强度；c在应力状态下会有应力腐蚀；d残余应力会降低零件精度。

5-22为什么在切削加工中一般都会产生冷作硬化现象？

机械加工过程中，因切削力作用产生的塑性变形，使晶格扭曲，畸变，晶粒间产生剪切滑移，晶粒被拉长和纤维化，甚至破碎，这些都会使表面金属的硬度和强度提高，故切削加工中易产生冷作硬化现象。5-23什么是回火烧伤？什么是淬火烧伤？什么是退火烧伤？为什么切削加工中易产生烧伤？

（1）回火烧伤是指对淬火钢，磨削区温度超过马氏体转变温度，工件表面原来的马氏体组织将转变为回火屈氏体索氏体等与回火组织相近的组织，使表面层硬度低于磨削前的硬度。（2）淬火烧伤：磨削区温度超过了相变温度，再冷却液的急冷作用，表层金属发生二次淬火，使表面层金属出现二次淬火马氏体组织，其硬度比原来的回火马氏体的高，在它的下层，因冷却较慢，出现了比原来的回火马氏体硬度低的回火组织。（3）退火烧伤：磨削区温度超过了相变温度，而磨削区域又无冷却液进入，表层金属将产生退火组织，表层硬度将急剧下降。（4）磨削加工易产生烧伤——因为磨削加工的特点：1磨削过程复杂，单位磨削力大，切深抗力较大，磨削速度高，磨削温度高。2因气流问题，切血液不能充分冷却工件。

5-24试述机械加工中表面层产生残余应力的原因。

表面层产生残余应力的原因：1切削时在加工表面金属层内有塑性变形发生，使金属层的比体积增大。由于塑性变形只在表层金属中产生，而表层金属比体积增大，体积膨胀，不可避免地要受到与它相连的里层金属的阻止，因此就在表面金属层产生残余压应力，而在里层金属中产生残余拉应力。（3）不同的金相组

织有不同的密度，亦有不同的比体积，从而金相组织变化后产生残余应力。

5-25试述机械加工中产生自激振动的条件。并用以解释再生型颤振、耦合型颤振的激振原理。

（1）机械加工产生自激振动的条件：E吸收>E消耗。（2）再生型颤振——由于切削厚度变化效应而引起的自激振动。（3）耦合型颤振——多自由度系统，在切削过程中因偶然干扰使刀架系统产生一定角频率的振动。

5-26 a）强烈振动原因——工艺系统刚度差。

b）升高刀具位置和改变工件转向，削弱自激振动。

c)采用两力加工，平衡切削力，提高工艺系统刚度。

d）增大事迹工作前角，使切削刚度下降，从而减小振动。

篇2：郑州大学机械设计基础第三版课后作业答案

UNIT1 1A

P15

4.1.elected，2.minimum，3.distinct，4.responsibility，5.pursue, 6.exploit，7.restrict，8.equip，9.granted，10.awarded

5.1.at large，2.on the basis of，3.in support of，4.apply for，5.is aiming at

1任何年满18岁的人都有资格投票(vote)。(be eligible to)Anyone over the age of 18 is eligible to vote.2.每学期开学前，这些奖学金的申请表格就会由学校发给每一个学生。(apply for, scholarship)A form to apply for these scholarships is sent by the university to each student before the start of each semester.3.遵照医生的建议，我决定戒烟。(on the advice of)On the advice of my doctor, I decided to give up smoking.4.公园位于县城的正中央。(be located in)The park is located right in the center of town.5.这所大学提供了我们所需的所有材料和设备。(facilities)The university provides all the materials and facilities we desire.1B

p21 13.1.challenge，2.had transformed，3.engage，4.occurred，5.urged, 6.cancel，7.prejudice，8.foundation，9.beliefs，10.constructive

14.1.rests with，2.in recognition of，3.in fact，4.provides for，5.keep...up

1.他内心深处知道，他们永远也不会再见了。(in one’s heart)He knew in his heart that they would never meet again.2.他们同意出版他的第一本书后，他终于感到自己快要成功了。(on the road to)He finally felt that he was on the road to success after they agreed to publish his first book.3.他停下来喝了一口(a sip of)水，然后继续讲话。(resume)He stopped to take a sip of water and then resumed speaking.4.这个大项目使我们忙得今年都无法安排一次度假了。(engage;so much that)The big project engages us so much that we can’t manage to take a holiday this year.5.氧气(oxygen)是气体中最重要的一种，正如水是液体中最重要的一种一样。(just as)Just as water is the most important of liquids, oxygen is the most important of gases.UNIT2

2A

p37

4.1.version，2.publications，3.click，4.spotted，5.refugees, 6.entries，7.financial，8.full-time，9.detailed，10.annual

5.1.set up，2.came across，3.referred...to ，4.check out，5.learnt of / learned of

1.警察们正忙着填写关于这场事故的各种表格。(fill out)The policemen are busy filling out forms about the accident.2.我想在还车之前把油箱(fuel tank)加满。(fill up)I want to fill up the fuel tank before returning the car.3.如果你要投诉，最好遵循正确的程序。(follow the procedure)If you want to make a complaint, you’d better follow the correct procedure.4.要不是约翰帮忙，我们绝不会这么快就完成实验。(without)We couldn’t have finished the experiment so soon without John’s help.5.暴风雨之后，岸边的人们焦急地搜索湖面以期发现小船的踪迹。(scan for)After the storm, the people on the shore anxiously scanned the lake for any sign of the boat 那时他刚刚被提升为公司副总裁不久，所以他并没有期待六个月内还会有升职。

2B p43 13.1.stressed，2.distinguished，3.invest，4.matured，5.covered，6.soured，7.concept，8.balance，9.discount，10.discipline

14.1.paid off，2.make ends meet，3.To this day，4.picked up，5.thanks to 1.没有身份证(ID card)我不能放任何人进来，但对你来说是例外(exception)。(in one’s case)I’m not supposed to let anyone in without an ID card, but I’ll make an exception in your case.2.他已经从失败中汲取教训，不会犯同样的错误。(learn a lesson from)He has learned his lesson from the failure and won’t repeat the mistake.3.我对你的能力很有信心，相信你一定能成功。(have faith in)I have great faith in your ability — I’m sure you’ll succeed.4.即使下着雨，我们还是继续比赛。(even though)Even though it was raining, we still went on with our match.5.我醒过来时，发现自己躺在医院的床上。(find oneself doing)I woke up to find myself lying on a hospital bed.UNIT3 3A p59 4.1.attractive 2.fascination 3.statement 4.despite 5.items 6.define 7.image 8.concerned

9.belongings 10.necessities

5.1.step back 2.identify with 3.dressing up 4.turned to/looked to 5.feed off

1.我们需要通过减少道路上的车辆以降低燃料消耗。(consumption)We need to cut down on our fuel consumption by having fewer cars on the road.2.电费上涨增加了我们的负担。(add to)The rise in power costs has added to our burden.3.你应该自己判断行事，别总是跟在你哥哥的后面。(follow the lead)You should judge by yourself, and not always follow your brother’s lead.4.那种发型今年很流行，但是我想明年就会过时。(in fashion)That hairstyle is in fashion this year, but I am afraid it will be out of fashion next year.5.在追求真理的过程中，我们注定(fate to)要遭受失败的痛苦。(in one’s quest for)We are fated to suffer from many failures in our quest for truth.3B p65 13.1.economic 2.estimated 3.measurable 4.inspired 5.maximize 6.motivate 7.created 8.distribute 9.concerning 10.abuse

14.1.by name 2.identify(her)with 3.participate in 4.speak for 5.take(firm)action

1.我发现量入为出地过日子越来越难了。(increasingly)I find it increasingly difficult to live within my income.2.现代政治家们都试图以电视讲话来影响普通百姓。(reach out)Modern politicians try to reach out to ordinary people in their TV speeches.3.应该帮助学生对人生采取积极的态度。(adopt)Pupils should be helped to adopt a positive attitude to life.4.希望全班同学参加这些讨论。(participate in)Everyone in the class is expected to participate in these discussions.5.如果你犯了罪就必须受到惩罚。(crime)If you commit a crime you must expect to be punished.UNIT4 4A p79 4.1.signal 2.crash 3.distress 4.grace 5.exploded 6.collision 7.lowered 8.beamed 9.scatter 10.destruction

5.1.combed through 2.in any case 3.ended in 4.bound for 5.on board

1.她在公共汽车站一直等到末班车进站。(come in)She waited at the bus stop until the last bus came in.2.如果我们能帮得上忙，尽管和我们联系。(contact)If there is any way we can be of assistance, please do not hesitate to contact us.3.他需要多少船务人员才能使他的游艇(yacht)航行？(crew)How many crew does he need to sail his yacht? 4.虽然她的新书没有上一本好，但是我还是喜欢它。(not quite as)I enjoyed her new book though it’s not quite as good as her last one.5.我从未遇到过如此善良的人。(never before)Never before have I met such a kind person.4B p85 13.1.wandering 2.unloading 3.crushed 4.slightest 5.appreciation 6.giant 7.steer 8.knelt 9.leaped 10.slammed

14.1.as good as new 2.in the nick of time/in time 3.at play 4.head for/make for 5.put away

1.公共汽车放慢速度并停下，让那位乘客上车。(slow down)The bus slowed down and stopped to allow the passenger to get on board.2.许多车子都驶过去了，可是没有一辆愿意让我们搭便车。(roll by)Many vehicles rolled by, but no one offered us a ride.3.请勿践踏草地。(get off)Please get off the grass.4.他按妻子的吩咐，一下班就去了市场。(make one’s way)He made his way to the marketplace right after work, as his wife had asked him to do.5.值得庆幸的是，史蒂夫(Steve)从自行车上摔下来时没有摔断骨头。(luckily)Luckily, Steve didn’t break any bones when he fell off his bike..UNIT5 5A

p99 4.1.was sinking 2.specialty 3.purely 4.discourage 5.unlikely 6.dynamics 7.actually 8.reasonably 9.have perceived 10.extended

5.1.took a deep interest in;2.fell into;3.sign up;4.try(it)out;5.dropped out of

1.我们得把感情放在一边，从专业的(professional)角度来对待这件事。(from a...standpoint)We have to put aside our emotions and take it from a professional standpoint.2.这部戏非常精彩，我很快就沉浸于激动人心的剧情之中。(lose oneself in)The play was so wonderful that I soon lost myself in the excitement of it.3.她没有什么爱好 —— 除非你把看电视也算是一种爱好。(unless)She hasn’t got any hobbies — unless you call watching TV a hobby.4.他说他是直接从市长本人那里得到这个信息的。(first-hand)He said that he had got the information first-hand from the Mayor himself.5.既然你不能回答这个问题，我们最好问问别人。(since)Since you can’t answer the question, perhaps we’d better ask someone else

5B p105 13.1.bound 2.sustain 3.obstacle 4.restored 5.approval 6.shift 7.emphasize 8.undergo 9.invincible 10.appearance

14.1.set out 2.at a time 3.in...shape 4.stopped short 5.turned to

1.由于公共汽车司机突然刹车(brake)，旅客们都不由自主地向前摔倒。(pitch forward)All the passengers pitched forward because the bus driver braked sharply.2.这个协议将冲破对自由贸易设置的障碍。(break through;obstacle)This agreement will break through the obstacles to free trade.3.我刚放下叫出租车的电话，车就来了。(soon after)The taxi arrived soon after I rang for it.4.在过去不管我什么时候到家，我父母总会等我。(no matter)My parents always waited up for me no matter what time I got home.5.由于没有一方愿意让步，两个公司之间的对话完全破裂了。(break down)Talks between the two countries completely broke down, because neither of them wanted to give in.UNIT6 6A p119 4.1.clapped 2.defend 3.quit 4.perfection 5.interview 6.survey 7.exclusive 8.storage

9.observed 10.cover

5.1.count...out 2.be unaware of 3.stopped in his tracks 4.At times 5.turn...around

1.那件工作很难做，不过我想试试看。(have a shot)It’s a difficult job, but I’d like to have a shot.2.这是一本关于商务实践而非理论的书。(as opposed to)This is a book about business practice as opposed to theory.3.社会活动从未耽误她的学习。(in the way)Social activities never get in the way of her studies.4.直到1911年人们才发现第一种维生素(vitamin)。(It is not until...that)It was not until 1911 that the first of the vitamins was identified.5.很明显，自然灾害是造成这个国家经济危机的原因。(crisis)Natural disasters have obviously contributed to the country’s economic crisis

6B p125 13.1.deprived 2.healthful 3.combine 4.determined 5.lifestyle 6.balance 7.approach 8.solutions 9.miserable 10.deserves

14.1.out of reach 2.in tune with 3.set your mind to 4.come off 5.trail and error

篇3：郑州大学机械设计基础第三版课后作业答案

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