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1、专业好文档内蒙古科技大学 2005/ 2006学年第二学期液压与气动技术 B卷试题课程号：0401360考试方式：闭卷考试使用专业、年级： 任课教师：乔文刚考试时间：2006年7月17日上午8：3010：30一、填空（每空1分，共48分）1、液压系统的联结形式（）、（）、（）。2、液压传动设备的基本组成包括（）、（）、（）、（）。3、液压系统的工作压力由（）决定，执行元件运动速度由（）决定。4、泵的理论流量与参数（）有关，而实际流量的影响参数为（）。5、齿轮泵的排量与参数（）有关，设计时选参数（）可使排量较大而结构尺寸又不增大。6、双作用叶片泵的叶片倾角方向采用（），而单作用叶片采用（），这样
2、主要为减少叶片与定子间的（）。7、定量泵包括（）,（），变量泵包括（）,（）。8、轴向柱塞泵的排量公式为（），从流量均性考虑应选用（）柱塞。9、柱塞缸运动速度与缸筒内径关系（）。差动油缸应采用（）类型的缸，可得差动速度为（），若使缸速进退相等，应得（）几何关系，当活塞杆直径变小时，则活塞运动速度将（）及作用力将（）。10、溢流阀的主要作用为（）、（）、（），在变量泵系统中，主溢流阀的作用是（）。11、采用出口节流调速系统，若负载减小，则节流阀前的压力就会（）。正常工作时，其中溢流阀起（）作用。12、调速阀是由（）阀和（）阀连接而成。三位换向阀中位机能常用的有（）、（）、（），其中（）可使泵卸荷
3、，（）可实现油缸的差动连接。13、单向调速阀 符号（） 二位二通常闭行程阀 符号（）电磁溢流阀 符号（）二、计算题（16分） 一液压马达排量q=80ml/r,负载扭矩为50N.m时，测得其机械效率为0.85，将此马达做泵使用，在工作压力为时，其机械损失扭矩与上述液压马达工况相同，求此时泵的机械效率。三、分析计算（18分）图示回路溢流阀的调整压力，减压阀的调整压力为，试分析下列情况，并说明减压阀阀口处于何工作状态（管路及单向阀压力损失不计）1、当泵压力时，夹紧缸夹紧后A、C点压力为多少？2、当泵工作压力由于工作缸快进，压力降到时（工件原先处于夹紧状）A、C点压力各为多少？3、夹紧缸夹紧工件前做空
4、载运动时，A、B、C三点压力各为多少？四、分析题（10分） 试画简图说明直动式溢流阀和先导式溢流阀的工作原理。这两种阀中的阻尼孔各起什么作用？如果阻尼孔堵塞，对二者的使用将各产生什么后果？五、（12分）液压缸A和B并联，要求缸A先动作，速度可调，且当A 活塞运动到终点后，缸B才动作，试问图示回路能否实现要的顺序动作？在不增加元件数量的情况下应如何改进？ 内蒙古科技大学 2005/ 2006学年第二学期液压与气动技术 B参考答案课程号：0401360考试方式：闭卷考试使用专业、年级： 任课教师：乔文刚考试时间：2006年7月17日上午8：3010：30一、填空题（每空1分，共48分）1、管式、板
5、式、集成块（叠加式）2、能源装置、执行装置、控制调节装置、辅助装置3、负载，流量4、n,q; n,q,（p）5、z,m,b; z小m大6、前倾，后倾，压力角7、齿轮泵、双作用叶片泵；但作用叶片泵、轴向柱塞泵8、；奇数、较多9、无关，单杆双作用，增大，减小10、定压，安全，卸荷（背压），安全11、增大，溢流定压12、节流阀，定差件压阀，串连，O,H,Y(P),H,M13、二、计算（16分）解：对马达：（3分） 得： （3分） 对泵：（4分） （3分） （3分） 三、分析计算（18分）1、（6分） 减压阀口处于微小开启状态2、（6分） 减压阀口全开3、（6分） 减压阀口为全开四、分析题（10分）答
6、：（5分） （1）（i）直动式溢流阀工作原理：利用阀芯下腔的液压力和上腔的弹簧力相平衡的原理。简图如下：(ii)先导式溢流阀工作原理：它有先导阀和主阀组成。当系统压力增大到使先导阀打开时，液流通过阻尼孔、先导阀流回油箱。由于阻尼孔的阻尼作用，使主阀右端的压力大于左端的压力，主阀在压差的作用下向左移动，打开阀口，实现溢流作用。（2分） （2）（i）直动式溢流阀阻尼孔作用：防止阀芯产生振动；通油 (ii)先导式溢流阀阻尼孔作用：油液流动时，产生压差使液压力与主阀芯的弹簧力相平衡进行工作。（3分） (3)（i）如果直动式溢流阀阻尼孔堵塞，则油不能流到阀芯底部，阀芯永远打不开，不能通油，油路相当于断路
7、。 （ii）如果先导式溢流阀阻尼孔堵塞，则不能形成压差，不能进行先导控制。五、（12分） 答：（2分） 不能实现顺序动作 （5分） 原因：缸A速度可调时（进油路节流调速），主溢流阀为开启，此时顺序阀必为开启，即缸A、B为同时动作 （5分）改进：（i）将节流阀改为旁路节流调速 （ii）或将顺序阀改为远控（即控制油K与节流阀和缸A之间油路接通）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
8、injury, while Slater has 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 Charnleys effort in their first pool match against England on the opening day.A
9、ussie winger Jarryd Hayne is the competitions 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 to
10、urnament high 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.Id give every award back in a heartbeat just to get across the line this weekend, said Williams.The (lack of) air up there Wa
11、tch mCayman Islands-based Webb, the head of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebrations and will attend Citys Premier League match at Chelsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC S
12、port.For me its about how he felt and I would like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedings against CSKAfor the racist behaviour of their fans duringCitys 2-1 win.Michel Platini, president of European footballs governing body, has also ordered
13、 an immediate investigation into the referees actions.CSKA said they were surprised and disappointed by Toures complaint. In a statement the Russian side added: We found no racist insults from fans of CSKA. Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as ea
14、rly 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 humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the t
15、roposphere) 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 of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the
16、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 resembling an Olympic diving platform.They blew it in 2008 when they got caught cold in the final and they will not make the
17、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 by Englands Josh Charnley in the opening game of the tournament.That could be classed as a weakness, a team under-cooked -
18、 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 - strong defence, especially on their own goal-line, completing sets and a good kick-chase. Theyve been great at all the unglamorous stuff
19、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 Thurston, Cooper Cronk, Cameron Smith and either Billy Slater or Greg Inglis at full-back they have a spine that is unmatched in rugby league. Th
20、ey 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.
