东大机械设计基础I复习题答案
机械设计基础I复习题答案二、计算题计算图示机构的自由度，指出存在的复合铰链、局部自由度或虚约束判断该机构是否具有确定的运动，说明理由。 file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image002.gif解：E（F）为虚约束，D和B处存在局部自由度file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image004.giffile:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image006.gif该机构具有确定的运动，主动构件数与自由度数相等。 三、计算题图示轮系中，已知file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image008.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image010.gif，齿轮1的转速file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image012.gif，求file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image014.gif及行星架的转速file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image016.gif 时齿轮3的转速file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image018.gif。file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image020.gif解：该轮系为一差动轮系。 （1）根据同心条件，轮1和轮2的中心距应等于轮3和轮2的中心距，对于标准齿轮，相啮合的齿轮模数相等，故 file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image022.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image024.gif，则有 file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image026.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image028.gif （2）当file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image016.gif时，即行星架H固定，该轮系成为定轴轮系，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image030.gif,file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image032.gif 齿轮3的转向与齿轮1的转向相反。 四、计算题 图示为单个普通螺栓连接，当螺栓的预紧力为file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image034.gif时，试写出被连接件所能承受的横向力file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image036.gif的表达式，并说明式中各符号的意义。file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image038.jpg 解：根据不滑移条件，可知file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image040.gif 所以，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image042.gif，式中，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image034.gif为预紧力，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image045.gif为接合面间的摩擦系数，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image047.gif摩擦接合面数，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image049.gif螺栓个数，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image051.gif可靠性系数，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image036.gif横向外载荷。题中，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image054.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image056.gif，故 file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image058.gif 五、计算题图示为轴系由一对30208滚动轴承支承。已知：轴向外载荷file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image060.gif，径向载荷分别为file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image062.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image064.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image066.gif。冲击载荷系数file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image068.gif，工作温度为100℃。轴承数据为file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image070.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image072.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image074.gif，派生轴向力file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image076.gif。file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image078.gif时，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image080.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image082.gif；file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image084.gif时，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image086.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image074.gif。试求该轴承寿命L10h。file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image089.gif解:（1）计算派生轴向力file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image091.gif、file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image093.giffile:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image095.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image097.gif（2）计算轴向载荷file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image099.gif、file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image101.giffile:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image103.gif，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image105.gif（3）计算当量动载荷file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image107.gif、file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image109.gif file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image111.gif， file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image113.giffile:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image115.gif （4）计算轴承寿命file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image117.gif file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image119.gif，故按照轴承1计算，file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image121.giffile:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image123.gif 六、分析题图示为蜗杆——斜齿圆柱齿轮传动，蜗杆主动，右旋，转向如图。为使Ⅱ、Ⅲ轴上的轴向力方向相反。试求：（1）蜗轮的螺旋线方向；（2）齿轮3、4的螺旋线方向；（3）蜗轮2、齿轮3的受力分析。file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image125.gif file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image127.gif
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