电大《汽车机械基础》期末复习题及参考答案【最新版.doc

电大汽车机械基础期末复习题及参考答案一、填空题1、力的三要素:力的大小、力的方向和力的作用点或作用线.2、力是物体间的相互作用，其效果是使物体的运动状态发生改变或物体发生变形。3、作力的多边形时，改变各分力作图的先后次序，将得到 不同 力的多边形，所求得的合力_相同_。4、力偶的三要素：力偶的大小、力偶的转向、力偶的作用平面。5、材料的强度是材料抵抗破坏的能力，材料的刚度是材料抵抗变形的能力，构件的稳定性是维持其原有平衡形式的能力6、杆件变形的基本形式有轴向拉伸和压缩、剪切与挤压、扭转、弯曲以及组合变形。7、液压传动中，常用的工作介质是 液压油 ，系统用它来传递能量。8、液压传动系统是由动力元件、执行元件、控制元件、辅助元件和工作介质五部分组成。9、油箱的作用为储油、散热、分离油液中的空气和沉淀污物等。10、运动副是两构件的直接接触组成的，能保持相对运动的连接，按两构件的接触形式的不同，运动副可分为低副和高副两大类。11、汽车中最常用的连接有 螺纹连接 、 键 、 花键 和销连接。12、带传动在汽车中的应用有两种，一是 V带 传动，另一种是 同步带 传动。13、一齿轮传动，主动轮齿数Z1=32，从动轮齿数Z2=80，则传动比i= 2.5 。若主动轮转速n1=1200r/min，则从动轮转速n2= 480r/min 。14、轴承按其工作的摩擦性质可分 滑动轴承 和 滚动轴承 两大类。15、在汽车中，离合器的作用是 接合 或 切断 变速器与驱动桥间的动力。二、选择题1、关于两物体间的相互作用，下面说法正确的是 （ C ）A、 马拉车不动，是因为马拉车的力小于车拉马的力。B、 马拉车前进，是因为马拉车的力大于车拉马的力。C、 马拉车不论动还是不动，马拉车的力的大小总等于车拉马的力的大小。D、 马拉车不动或匀速前进时，才有马拉车的力与车拉马的力大小相等。2. 关于作用力和反作用力, 下列说法正确的是（ B ）A、物体发生力的作用时，先有作用力，然后产生反作用力。B、作用力与反作用力大小相等、方向相反。C、作用力与反作用力的合力为零。D、作用力与反作用力是一对平衡力。3、放置在输送带上的物体，所受到的摩擦力与输送带运动方向的关系是（B ）A、相反 B、相同 C、垂直4、液压系统的动力原件是（ D ）A动力机 B液压阀 C 液压缸 D 液压泵5、液压传动的执行元件是（ C ） A.电动机 B .液压泵 C. 液压缸或液压马达 D . 液压阀6、关于溢流阀的描述正确的是（ B ）A常态下阀口是常开的 B阀芯随着系统的压力的变化而移动 C进出油口均有压力 D. 一般连接在液压缸的回油路上。7、卸载回路属于_回路 （ B ）A方向控制回路 B 压力控制回路 C 速度控制回路 8、液压系统中的压力能来自于（ D ）A压力控制阀 B液压缸 C液压马达 D液压泵9、增压回路的增压比等于（ C ）A、大、小两液压缸直径之比 B、大、小两液压缸直径之反比C、大、小两活塞有效作用面积之比 D、大、小两活塞有效作用面积之反比10、一对齿轮的传动比等于（B） A、主动齿轮的齿数从动齿轮的齿数B、从动齿轮的齿数主动齿轮的齿数 C、从动齿轮的齿数主动齿轮的齿数11、属于啮合传动类的带传动是（ D ）。 A平带传动 B. V带传动 C圆带传动 D同步带传动12、普通螺纹的公称直径是指（ A ）A、大径 B、小径 C、中径 D、顶径 E、底径13、以下是决定钢性能的主要元素是（ B ）。A、锰 B、碳 C、硫 D、硅14、以下几种号牌汽油，辛烷值最高的是（ C ）A、90号 B、93号 C、97号 D、95号15、汽车上的连杆瓦常用以下哪种材料制造。（ C ）A、纯铜 B、纯铝 C、青铜 D、灰铸铁三、判断题（ ）1、力是改变运动状态的原因，不是维持运动的原因。（ ）2、有力作用物体就运动，无力作用物体就静止。（ ）3、物体的平衡是物体相对地面处于静止状态。（ ）4、压力调定回路主要由溢流阀等组成。（ ）5、增压回路的增压比取决于大、小液压缸直径之比。（ ）6、强度是指金属抵抗变形和不受损坏的能力。（ ）7、疲劳断裂是指零件受到的外力超过其强度极限而发生的断裂。（ ）8、金属材料的硬度越大，其韧度也越高。（ ）9、铁碳合金是指只由铁和碳两种元素组成的合金。（ ）10、合金钢是指在碳钢的基础上特意加入一种或多种元素而形成的一类钢。（ ）11、汽车上燃烧用的汽油，其挥发性越高越好。（ ）12、平面连杆机构各构件的运动轨迹一定在同一平面或互相平行的平面内。（ ）13、在曲柄摇杆机构中，摇杆两极限位置的夹角称为极位夹角。（ ）14、铰链四杆机构中的最短杆就是曲柄。（ ）15、一切摩擦传动的传动比都不准确。（ ）16、两个相互配合的螺纹，其旋向相同。（ ）17、一般来说，齿轮传动的传动效率要比链传动的传动效率要高的多。（ ）18、蜗杆传动具有传动比大，承载能力大，传动效率高等特点。（ ）19、周转轮系中，中心轮与行星架的固定轴线必须在同一轴线上。（ ）20、大齿轮带动小齿轮转动是属于减速运动。四、名词解释1、啮合：齿轮副的一对齿轮的齿依次交替接触，从而实现一定规律地相对运动的过程和形态称为啮合2、齿轮传动比：主动齿轮与从动齿轮转速之比。3、曲柄：能做整周旋转的连架杆称为曲柄。4、约束：限制物体某些运动的条件称为约束。5、许用应力：构件材料在保证安全工作的条件下允许承受的最大应力。五、简答题1、齿轮传动有哪几种失效形式？答：齿轮传动常见的失效形式有：轮齿折断、齿面磨损、齿面点蚀、齿面胶合、塑性变形。2、改进轴的结构，避免应力集中的方法有哪5种？答：直径变化处用圆角过渡；用圆盘铣刀加工键槽或面铣刀加工键槽；轴上有花键时用渐开线花键；减小轮毂边缘处的刚度，增大配合处轴颈；轴上尽量不要开不必要的小孔，切口和凹槽；3、铰链四杆机构中，曲柄存在的条件是什么？答：连架杆与机架中必有一个杆是最短杆；最短杆和最长杆长度之和小于或等于其他两个杆长度之和。4、螺纹连接为什么要防松？常见的防松方法有哪些？答：螺纹在冲击、振动、变载荷作用下或温度变化很大时候，其自锁性不能防止螺母脱落，可能松动。常用的方法有：摩擦力，机械和利用附加材料防松。5、联轴器和离合器的功用是什么？两者有什么区别？答：联轴器主要用作轴与轴的联接，以传递转矩和运动的一种装置。离合器是机器在运转过程中主、从动部分在同一轴线上传递动力或运动时，具有结合或分离功能的装置。两者区别是在机器正常工作时是否能随意脱开。6、什么是齿面胶合？防止齿面胶合的方法有哪些？答：胶合是相啮合齿面的金属，在一定压力下直接接触发生粘着，同时随着齿面间的相对运动，使金属从齿面上撕落而引起的一种严重粘着磨损现象。提高齿面硬度和减低表面粗糙度；低速采用粘度大的润滑油；高速采用抗胶合添加剂的润滑油。7、轴上零件的周向定位和固定的目的是什么，常见的周向定位和固定的结构有哪些？答：轴上零件的周向定位和固定是为了传递扭矩，防止零件与轴产生相对转动。常见方法有：键，花键，销，紧定螺钉，过盈配合，非圆轴承。六、计算题1、已知某平带传动，主动轮直径1=80mm，转速n1=1450r/min，要求从动轮转速n2为290r/min。试求传动比i和从动轮直径2的大小。解：传动比：i=n1/n2=1450/290=5从动轮直径：D2=iD1=580=400mm2、如图，已知各齿轮齿数为Z1=10，Z2=18，Z3=30，Z4=20，输入转速n1=120转/分，齿轮Z1转向如图所示。求齿轮1和齿轮4的传动比i14，齿轮4的转速n4，并判断齿轮4的转向。解：传动比：i14=Z4Z2/Z3Z1=2018/3010=1.2 转速：n4=n1/i14=120/1.2=100r/min七、作图题1、请画出单向阀、溢流阀的职能符号：2、根据蜗杆的旋转方向，在图上画出蜗轮的回转方向。（蜗轮的选装方向为逆时针旋转）请您删除一下内容，O(_)O谢谢！2015年中央电大期末复习考试小抄大全，电大期末考试必备小抄，电大考试必过小抄Shanghais Suzhou Creek has witnessed much of the citys history. Zhou Wenting travels this storied body of water and finds its most fascinating spots. Some lucky cities can boast a great body of water, like London with the river Thames and Paris with the river Seine. Shanghai is privileged enough to have two great bodies of water: Huangpu River and Suzhou Creek.Huangpu River became famous when colonists established clusters of grand buildings on its banks on what became known as the bund. Today, the bund overlooks the breathtaking skyline of Lujiazui financial district. Shanghais other body of water, however, Suzhou Creek, has been somewhat overshadowed. Suzhou Creek links the inland cities of Jiangsu province with Shanghai. When the British colonists, who arrived in the city after it was opened as a commercial port in 1843 found they could reach Suzhou, Jiangsu province, via the creek, they named it Suzhou Creek. Thanks to its location, a large amount of cargo and travelers were transported via the creek before rail links were established. But after a century of being utilized as a waterway to transport goods and labor, the creek grew dark and smelly. Industrial factories were established along the banks. In the 1990s it became a key task of the city government to clean the creek. Suzhou Creek, which snakes 17 km from the iconic Waibaidu Bridge downtown to the outer ring road in west Shanghai, maps the changing periods of the citys history, including the imprints of the concessions, the beginning of industrialization and the improvement in peoples living conditions. Where the Bund began In-between the shopping street of East Nanjing Road and the Bund, are a cluster of streets that give me the illusion that I am no longer in modern Shanghai. The streets are narrow and old and criss-cross each other. Any old residential house may turn out to be a former office of the British, constructed in the 1880s. Pawnshops and hardware stores that are hard to find elsewhere, are plentiful here. This area, at the confluence of Huangpu River and Suzhou Creek, is called the Bund Origin. Countless tour buses stop at the site every day and visitors from around the world get off to see this place, the starting point of the concessions in the city. It all started in 1872, when the former British Consulate General was constructed and the Bund began its transformation into an the financial street of the East. Now the site of the former consulate is called “No 1 Waitanyuan”, which translates to “the Bund Origin”, to honor its beginnings. The entire complex of this historical site comprises of five buildings, the former British Consulate General, the official residence of the consul, the former Union Church, the church apartments and the former Shanghai Rowing Club. The size of the courtyard is equivalent to that of four standard soccer fields. The building of the former consulate is a two-storey masonry building on an H-shaped plan in typical English renaissancestyle. The building is designed with a five-arch verandah on the ground floor with a raised terrace facing the garden, while the facade features an entry portico beneath a colonnaded loggia. It has been turned into a caf where dinner and afternoonteaare available. Visitors can choose to sit indoors or outdoors to enjoy the magnificent gardens with nearly 30 ancient trees.Yuanmingyuan Road behind the complex is also a historical site. The road has been revamped as a pedestrian shopping street and high-end brands have seized the best spots. Altogether, 14 old buildings, including those used for offices and residences constructed during 1920s and 1930s, remain. Today, it is a popular location for commercialfashionphoto shoots. New Tianan Church, or Union Church, stands at the intersection of Yuanmingyuan Road and Suzhou Creek. The church, designed in the style of the English countryside, has a capacity of 500 people. It was very popular during the concession period but was converted into factory offices after 1949. The church we see today is a replica, the original burned down in 2007. There used to be an outdoor swimming pool, the first of its kind in Shanghai, beside the church but has been filled-in and is now a small garden. Bridge of romance There is perhaps no other place thats more representative of Shanghai than this bridge, which appears in quite a lot ofmovies about the city. Dozens of couples visit every day to pose for their pre-wedding photos on the bridge where Suzhou Creek begins and interconnects with Huangpu River. This is Waibaidu Bridge, or the Garden Bridge. The soon-to-be-wed couples pose in splendid attire on the bridge, leaning against the railing or sitting on the wooden floor. Some even risk walking into the middle of the road to get the perfect shot.Colorful lights illuminate the bridge throughout the night, making it a picturesque place for pre-wedding portraits and lovers to meet. Constructed in 1873 and designed by a British company, the 106-meter-long bridge was the first-ever major bridge in Shanghai. In 1856, the first large wooden bridge, Wells Bridge, was built over Suzhou Creek but the bridge toll led to complaints from citizens. So 17 years later, another wooden bridge, which did not require tolls, was built. People called it Waibaidu, which means “going across for free”. The bridge was renovated as a steel truss structure in 1907. Because nearly 40 bridges have now been built over Suzhou Creek, the bridge is no longer a traffic artery but is more of an observation deck for tourists. It is a tradition in Shanghai for a grandmother to walk across a bridge with their grandchild when he or she reaches one month. This represents that the newborn has overcome all the twists and turns and its journey will be safe and smooth throughout his or her life. Waibaidu Bridge is always the best option because its the icon of Shanghai. The picture of my daughter when she was a baby held by her grandmother was also taken here. Its like a family tradition, says Wang Xuefen, a Shanghai native who has a newborn grandson. Changning Riverside There is a 5-km stretch of waterfront by Suzhou Creek in Changning district on Changning Road from the intersection of Hami Road to Jiangsu Road. It has become a popular place to take a walk and sunbathe on the lawn. There is an overpass at the intersection of Changning Road and Gubei Road for people to enjoy the view of the creek and a 3-km plastic runway on both sides of Changning Road, which attracts people of all ages, Chinese and expat. Jogging on the two sides gives a different feeling because the north side is next to the creek, and the south side is adjacent to the residential highrises, which is like jogging in the jungle, says Xiao Xu, a 27-year-old woman who lives nearby. The riverside used to be completely different. Dozens of textile mills, chemical plants and machine manufacturing factories were set up along the creek in the 1920s. They brought industrialization but also pollution. From the 1930s the creek could no longer be used as a source for tap water, and no living fish or shrimp could be found. Suzhou Creek in my memory is dark and smelly. I used to go to the riverbank to watch the sewage disposal running out from the chemical plants when I was a little girl. We didnt know it was pollution. We thought it was a red waterfall, says Huang Qi, a 57-year-old Shanghai resident. So the residential houses along the creek were unpopular, and only migrants with low incomes would live in that area, she says. However, things have changed. The plants were closed and turned into riverside parks and the apartments in the new highrises, especially those facing the creek, are much sought after. East China University of Political Science and Law This is the famous former Saint Johns