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1、專業(yè)好文檔
內(nèi)蒙古科技大學(xué) 2005/ 2006學(xué)年第二學(xué)期
《液壓與氣動技術(shù)》 B卷試題
課程號:040136—0 考試方式:閉卷考試
使用專業(yè)、年級: 任課教師:喬文剛
考試時間:2006年7月17日上午8:30—10:30
一、填空(每空1分,共48分)
1、液壓系統(tǒng)的聯(lián)結(jié)形式()、()、()。
2、液壓傳動設(shè)備的基本組成包括()、()、()、()。
3、液壓系統(tǒng)的工作壓力由()決定,執(zhí)行元件運動速度由()決定。
4、泵的理論流量與參數(shù)()有關(guān),而實際流量的影響參數(shù)為()。
5、齒輪泵的排量與參數(shù)()有關(guān),設(shè)計時選參數(shù)()可
2、使排量較大而結(jié)構(gòu)尺寸又不增大。
6、雙作用葉片泵的葉片傾角方向采用(),而單作用葉片采用(),這樣主要為減少葉片與定子間的()。
7、定量泵包括(),(),變量泵包括(),()。
8、軸向柱塞泵的排量公式為(),從流量均性考慮應(yīng)選用()柱塞。
9、柱塞缸運動速度與缸筒內(nèi)徑關(guān)系()。差動油缸應(yīng)采用()類型的缸,可得差動速度為(),若使缸速進退相等,應(yīng)得()幾何關(guān)系,當活塞桿直徑變小時,則活塞運動速度將()及作用力將()。
10、溢流閥的主要作用為()、()、(),在變量泵系統(tǒng)中,主溢流閥的作用是()。
11、采用出口節(jié)流調(diào)速系統(tǒng),若負載減小,則節(jié)流閥前的壓力就會()。正常工作時,其中
3、溢流閥起()作用。
12、調(diào)速閥是由()閥和()閥連接而成。三位換向閥中位機能常用的有()、()、(),其中()可使泵卸荷,()可實現(xiàn)油缸的差動連接。
13、單向調(diào)速閥 符號()
二位二通常閉行程閥 符號()
電磁溢流閥 符號()
二、計算題(16分)
一液壓馬達排量q=80ml/r,負載扭矩為50N.m時,測得其機械效率為0.85,將此馬達做泵使用,在工作壓力為時,其機械損失扭矩與上述液壓馬達工況相同,求此時泵的機械效率。
三、分析計算(18分)
圖示回路溢流閥的調(diào)整壓力,減壓閥的調(diào)整
4、壓力為,試分析下列情況,并說明減壓閥閥口處于何工作狀態(tài)(管路及單向閥壓力損失不計)
1、當泵壓力時,夾緊缸夾緊后A、C點壓力為多少?
2、當泵工作壓力由于工作缸快進,壓力降到時(工件原先處于夾緊狀)A、C點壓力各為多少?
3、夾緊缸夾緊工件前做空載運動時,A、B、C三點壓力各為多少?
四、分析題(10分)
試畫簡圖說明直動式溢流閥和先導(dǎo)式溢流閥的工作原理。這兩種閥中的阻尼孔各起什么作用?如果阻尼孔堵塞,對二者的使用將各產(chǎn)生什么后果?
五、(12分)
液壓缸A和B并聯(lián),要求缸A先動作,速度可調(diào),且當A 活塞運動到終點后,缸B才動作,試問圖示回路能否實現(xiàn)要的順序動作?在不
5、增加元件數(shù)量的情況下應(yīng)如何改進?
內(nèi)蒙古科技大學(xué) 2005/ 2006學(xué)年第二學(xué)期
《液壓與氣動技術(shù)》 B參考答案
課程號:040136—0 考試方式:閉卷考試
使用專業(yè)、年級: 任課教師:喬文剛
考試時間:2006年7月17日上午8:30—10:30
一、填空題(每空1分,共48分)
1、管式、板式、集成塊(疊加式)
2、能源裝置、執(zhí)行裝置、控制調(diào)節(jié)裝置、輔助裝置
3、負載,流量
4、n,q; n,q,(p)
5、z,m,b; z小m大
6、前傾,后傾,壓力角
7、齒輪泵、雙作用葉片泵;但作用葉片泵、
6、軸向柱塞泵
8、;奇數(shù)、較多
9、無關(guān),單桿雙作用,,,增大,減小
10、定壓,安全,卸荷(背壓),安全
11、增大,溢流定壓
12、節(jié)流閥,定差件壓閥,串連,O,H,Y(P),H,M
13、
二、計算(16分)
解:對馬達:(3分) 得:
(3分)
對泵:(4分)
(3分)
(3分)
三、分析計算(18分)
1、(6分) 減壓閥口處于微小開啟狀態(tài)
2、(6分) 減壓閥口全開
3、(6分) 減壓閥口為全開
四、分析題(10分)
答:(5分) (1)(
7、i)直動式溢流閥工作原理:利用閥芯下腔的液壓力和上腔的彈簧力相平衡的原理。
簡圖如下:
(ii)先導(dǎo)式溢流閥工作原理:它有先導(dǎo)閥和主閥組成。當系統(tǒng)壓力增大到使先導(dǎo)閥打開時,液流通過阻尼孔、先導(dǎo)閥流回油箱。由于阻尼孔的阻尼作用,使主閥右端的壓力大于左端的壓力,主閥在壓差的作用下向左移動,打開閥口,實現(xiàn)溢流作用。
(2分) (2)(i)直動式溢流閥阻尼孔作用:防止閥芯產(chǎn)生振動;通油
(ii)先導(dǎo)式溢流閥阻尼孔作用:油液流動時,產(chǎn)生壓差使液壓力與主閥芯的彈簧力相平衡進行工作。
(3分) (3)(i)如果直動式溢流閥阻尼孔堵塞,則油不能流到閥芯底部,閥芯永遠打不開,不能
8、通油,油路相當于斷路。
(ii)如果先導(dǎo)式溢流閥阻尼孔堵塞,則不能形成壓差,不能進行先導(dǎo)控制。
五、(12分)
答:(2分) ①不能實現(xiàn)順序動作
(5分) ②原因:缸A速度可調(diào)時(進油路節(jié)流調(diào)速),主溢流閥為開啟,此時順序閥必為開啟,即缸A、B為同時動作
(5分)③改進:(i)將節(jié)流閥改為旁路節(jié)流調(diào)速
(ii)或?qū)㈨樞蜷y改為遠控(即控制油K與節(jié)流閥和缸A之間油路接通)
Winger Tuivasa-Sheck, who scored two tries in the Kiwis 20-18 semi-fi
9、nal win over England, has been passed fit after a lower-leg 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
10、in their first pool match against England on the opening day.
Aussie 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 attract
11、ed the most interest in the tournament so far.
The Kiwi - with a tournament 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 ac
12、ross the line this weekend," said Williams.The (lack of) air up there
Watch 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 t
13、o be at the match tomorrow and I have asked to meet Yaya Toure," he told BBC Sport.
"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-
14、1 win.
Michel Platini, president of European footballs governing body, has also ordered 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."
15、
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 humidity and limited cloud
16、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 of commercial airliners
17、 (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 resembling
18、 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 by
19、Englands 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 - strong defence
20、, especially on their own goal-line, completing sets and a good kick-chase. Theyve 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 Thurston, Cooper C
21、ronk, 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.