电大液压与气动技术B试题答案小抄参考

《电大液压与气动技术B试题答案小抄参考》由会员分享，可在线阅读，更多相关《电大液压与气动技术B试题答案小抄参考（5页珍藏版）》请在装配图网上搜索。

1、专业好文档20092010学年第一学期液压与气动技术考试试卷（B）参考答案题 号一二三四五总 分得 分 (2) 液压执行元件：液压执行元件指液压缸或液压马达，是将液压能转换为机械能的装置，其作用是在压力油的推动下输出力和速度（或转矩和转速），以驱动工作机构； (3) 控制调节元件：它包括各种阀类元件，其作用是用来控制液压系统中油液流动方向、压力和流量，以保证液压执行元件和工作机构完成指定工作； (4) 辅助元件：辅助元件如油箱、油管、滤油器等，它们对保证液压系统正常工作有着重要的作用； (5) 工作介质：工作介质指传动液体，通常被称为液压油。在液压系统中，液压油液用来传递动力和信号，并且起到润

2、滑、冷却和防锈等作用。2、液压泵正常工作的基本条件是什么？液压泵在液压系统中的工作压力取决于什么？答：1液压泵必须具有一个或若干个可以周期性变化的密封空间，即液压泵是靠密封空间的容积变化来工作的。2油箱内液体的绝对压力必须等于或大于大气压力，这是液压泵能够吸入油液的外部条件。为保证液压泵正常吸油，油箱必须与大气相通，或采用密闭的充压油箱。3液压泵必须具有相应的配流装置。它保证密封空间由小变大时只与吸油管相通，密封空间由大变小时只与压油管相通。液压泵在液压系统中的工作压力取决于系统中阻止液体流动的阻力，一般指的是负载。3、外啮合齿轮泵的困油现象及解决措施。答：外啮合齿轮泵要平稳地工作，齿轮啮合的

3、重合度必须大于1，即有两对轮齿同时啮合的时候，因此，就有一部分油液困在两对轮齿所形成的封闭油腔之内。这个封闭容积先随齿轮转动逐渐减小，以后又逐渐增大。封闭容积减小会使被困油液受挤压而产生高压，并从缝隙中流出，导致油液发热，轴承等机件也受到附加的不平衡负载作用；封闭容积的增大又会造成局部真空，使溶于油液中的气体分离出来，产生气穴，这就是齿轮泵的困油现象。 解决措施：通常是在两端盖板上开两个卸荷槽（或与齿轮端面相接触的零件上开两个卸荷槽），使封闭容积减小时通过一边的卸荷槽与压油腔相通，封闭容积增大时通过另一边的卸荷槽与吸油腔相通。两卸荷槽的间距必须确保在任何时候都不使吸油腔和压油腔相通。一、填空题

4、（每题2分，共30分）1、液压传动就是指在密封容积内,利用液体的 压力 能来传递动力和运动的一种 传动方式 。2、液压油的粘度随液压油的温度和压力而变，当压力增大时，液压油粘度 增大 ；当液压油温度升高时，液压油的粘度 下降 。3、根据度量基准的不同，液体的压力分为 绝对压力 和 相对压力 两种，大多数表测得的压力是相对压力。4、液压泵按结构分 齿轮泵 、叶片泵、 柱塞泵 三种，它们是利用密封容积 的变化来进行工作的，所以称为容积泵。5、一般的外啮合齿轮泵的进油口 大 ，出油口 小 ，这主要是为了解决外啮合齿轮泵的径向力不平衡问题。6、常见的密封方法有 间隙 密封、活塞环密封、 密封圈 密封三

5、种。7、斜盘式轴向柱塞泵的缸体、柱塞、斜盘、配油盘中随输入轴一起转动的为 缸体 、 柱塞 。8、在结构上所有液压阀都是由 阀体 、 阀芯 和驱动阀芯动作的元部件等组成。9、所有的液压阀都是通过控制 阀体 和 阀芯 的相对运动而实现控制目的的。10、液压控制阀按其用途来分可分为 _方向阀_、压力阀、_流量阀_。11、调速阀是由_节流阀_和_定差式减压阀（差压式减压阀）_构成的一种组合阀。12、液压油的粘度的表示方法有_绝对粘度_、运动粘度和_相对粘度_。13、液压油的牌号是采用在 40 温度时的 运动 粘度的平均值来标号的。14、液压缸的结构主要包括 缸体组件 、 活塞组件 、密封装置、缓冲装置

6、、排气装置等五部分组成。15、根据改变流量方式的不同，液压系统的调速方法可以分为三种： 节流调速 、容积调速、 容积节流调速 。二、简答题（每题10分，共 30分）1、液压传动系统一般由几部分组成？各部分起什么作用？答：液压传动系统一般由五部分组成：动力元件、执行元件、控制调节元件、辅助元件、工作介质。(1) 动力元件：动力元件指液压泵，它是将原动机的机械能转换成为液压能的装置，其作用是为液压系统提供压力油，是液压系统的动力源；系 （部）年级专业班 级姓名考试课程20092010学年第一学期液压与气动技术考试试卷（B）参考答案三、分析题（10分）1、某液压系统，泵的排量q10m L/r，电机转

7、速n1200rpm，泵的输出压力p=5Mpa 泵容积效率v0.92，总效率0.84，求： 1）泵的理论流量； 2）泵的实际流量； 3）泵的输出功率； 4）驱动电机功率。1）泵的理论流量 qt=v.n.10-3=10×1200×10-312 L/min 2) 泵的实际流量 q qt .v12×0.9211.04 L/min 3) 泵的输出功率4）驱动电机功率四、应用题（10分） 1、说明处理一般液压故障的步骤。（10分）答：首先到现场观察故障现象，了解故障产生原因，故障产生前后设备运转状况，查清故障是在什么条件下产生的，并摸清与故障有关的其他因素以及故障的特点等。1

8、初步分析判断。分析判断时首先应注意到外界因素对系统的影响，在查明确实不是外界原因引起故障的情况下，再集中注意力在系统内部查找原因。其次是，分析判断时，一定要把机械、电气、液压3个方面联系在一起考虑，不能单纯只考虑液压系统；要分清故障是偶然发生的还是必然发生的。2列出可能的故障原因表。根据了解、询问、核实、检查所得到的资料列出可能的故障原因表。3仔细检查。根据所列故障原因表，先选择经简单检查核实或修理即可使设备恢复正常工作状态的项目，即采取先易后难的原则，排出检查顺序，以便在最短的时间内完成检查工作。4找出结论。根据检查结果确定故障部位。5验证结论。在实际工作中往往没有适当的试验装置来进行验证，

9、这时只好以更换泵、马达、阀等元件总成来作为排除故障的有效手段。对故障处理完毕后，应认真地进行定性、定量分析总结，从而提高处理故障的能力，防止以后同类故障的再次发生。令六、综合题（20分）下图为双泵供油快速运动回路原理图和液压缸动作循环图。1、指出各元件的名称；2、写出液压缸在静止、快进、工进和快退时油流过程。答：1-油箱，2-过滤器，3-双联泵，4-卸荷阀（外控外泄式顺序阀），5-三位四通电磁换向阀，6-单杆活塞式液压缸，7-溢流阀，8和9-单向阀。一、液压缸在静止时油流过程：1 23（左）41 3（右）971二、液压缸在快进时油流过程：1.进油：1 23（左）8 5（左）6无杆腔 3（右）9

10、2.回油：6有杆腔5（左）1三、液压缸在工进时油流过程：1.进油：1 23（左）41 3（右）95（左）6无杆腔2.回油：6有杆腔5（左）1四、液压缸在快退时油流过程：1.进油：1 23（左）8 5（右）6有杆腔 3（右）92.回油：6无杆腔5（右）1系 （部）年级专业班 级姓名考试课程Winger Tuivasa-Sheck, who scored two tries in the Kiwis' 20-18 semi-final win over England, has been passed fit after a lower-leg injury, while Slater h

11、as been named at full-back but is still recovering from a knee injury aggravated against USA.Both sides boast 100% records heading into the encounter but Australia have not conceded a try since Josh Charnley's effort in their first pool match against England on the opening day.Aussie winger Jarr

12、yd Hayne is the competition's top try scorer with nine, closely followed by Tuivasa-Sheck with eight.But it is recently named Rugby League International Federation player of the year Sonny Bill Williams who has attracted the most interest in the tournament so far.The Kiwi - with a tournament hig

13、h 17 offloads - has the chance of becoming the first player to win the World Cup in both rugby league and rugby union after triumphing with the All Blacks in 2011."I'd give every award back in a heartbeat just to get across the line this weekend," said Williams.The (lack of) air up the

14、re Watch mCayman Islands-based Webb, the head of Fifa's anti-racism taskforce, is in London for the Football Association's 150th anniversary celebrations and will attend City's Premier League match at Chelsea on Sunday."I am going to be at the match tomorrow and I have asked to meet

15、 Yaya Toure," he told BBC Sport."For me it's about how he felt and I would like to speak to him first to find out what his experience was."Uefa has opened disciplinary proceedings against CSKA for the "racist behaviour of their fans" during City's 2-1

16、win.Michel Platini, president of European football's governing body, has also ordered an immediate investigation into the referee's actions.CSKA said they were "surprised and disappointed" by Toure's complaint. In a statement the Russian side added: "We found no racist ins

17、ults from fans of CSKA." Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunda.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humid

18、ity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude o

19、f commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will slowly step out onto something re

20、sembling an Olympic diving platform.They blew it in 2008 when they got caught cold in the final and they will not make the same mistake against the Kiwis in Manchester.Five years ago they cruised through to the final and so far history has repeated itself here - the last try they conceded was scored

21、 by England's Josh Charnley in the opening game of the tournament.That could be classed as a weakness, a team under-cooked - but I have been impressed by the Kangaroos' focus in their games since then.They have been concentrating on the sort of stuff that wins you tough, even contests - stro

22、ng defence, especially on their own goal-line, completing sets and a good kick-chase. They've been great at all the unglamorous stuff that often goes unnoticed in the stands but not by your team-mates.It is as though their entire tournament has been preparation for the final.In Johnathan Thursto

23、n, Cooper Cronk, Cameron Smith and either Billy Slater or Greg Inglis at full-back they have a spine that is unmatched in rugby league. They have played in so many high-pressure games - a priceless asset going into Saturday.The Kiwis are a lot less experienced but winning a dramatic match like their semi-final against England will do wonders for their confidence.They defeated Australia in the Four Nations final in 2010 and the last World Cup, and know they can rise to the big occasion.5