【链传动】知识点总结
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<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">今天整理的知识点是<strong style="color: blue;"><span style="color: black;">链传动</span></strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">链传动的知识点常常</span><strong style="color: blue;"><span style="color: black;">在<span style="color: black;">选取</span>题、填空题、简答题</span></strong><span style="color: black;"><span style="color: black;">显现</span></span></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">请<span style="color: black;">大众</span>认真复习</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">滚子链的<span style="color: black;">构成</span></strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">滚子链</span></strong><span style="color: black;">由内链板，外链板，销轴，套筒，和滚子<span style="color: black;">构成</span>。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">销轴与外链板套筒与内链板均用<strong style="color: blue;"><span style="color: black;">过盈<span style="color: black;">协同</span>连接</span></strong>，分别<span style="color: black;">叫作</span>为外链接；内链接。而销轴与套筒，滚子与套筒之间则为<strong style="color: blue;"><span style="color: black;">间隙<span style="color: black;">协同</span></span></strong>。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">滚子与套筒之间的间隙<span style="color: black;">协同</span>让轮齿在与滚子接触时滚子<span style="color: black;">出现</span>滚动，变滑动摩擦为滚动摩擦，减小链条磨损。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">滚子链是标准件，其<span style="color: black;">重点</span>参数是链的节距P</span></strong></span><span style="color: black;">，它<span style="color: black;">指的是</span>链条上相邻两滚子中心间的距离。截距P增大链的各部分尺寸相应增大，承载力<span style="color: black;">亦</span>相应<span style="color: black;">加强</span>，但重量<span style="color: black;">亦</span>随之增大。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">链的长度用链节数<span style="color: black;">暗示</span></span></strong><span style="color: black;">，为了使链条连成环形，正好是外链板与内链板相连接，</span><span style="color: black;"><span style="color: black;">因此</span>链接数最好为</span><strong style="color: blue;"><span style="color: black;">偶数</span></strong><span style="color: black;">。当链接数为偶数时，采用连接链节，其形状与外链节<span style="color: black;">同样</span>，只是链节<span style="color: black;">一边</span>的外链板与销轴为间隙<span style="color: black;">协同</span>，接头处的可用弹簧锁片或开口销等止锁件固定。当链接数为奇数时，可采用过渡链节，<span style="color: black;">因为</span>过渡链节的链板受力时有附加弯矩<span style="color: black;">功效</span>，<span style="color: black;">因此</span>强度仅为普通链接的80%<span style="color: black;">上下</span>。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">链传动的多边形效应</strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">将链轮的圆周速度v1=R1*w1，分解为沿链条前进方向的分速度v和垂直链条前进方向的分速度V</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">当链轮转动的时候，相位角β<span style="color: black;">出现</span>变化，沿链条前进方向的分速度V和垂直链条前进的方向的分速度都会随之<span style="color: black;">出现</span>变化。链条前进的速度v由小变大，再由大变小，每转过一个链节，链数v周期性变化一次，它使得传动不<span style="color: black;">安稳</span>，并产生周期性的震动，同理垂直于链条前进方向的分速度V的<span style="color: black;">体积</span>。先增大到0，又由0减小，呈周期性变化。显然</span><span style="color: black;">当主动轮匀速转动时，链速是变化的，<span style="color: black;">况且</span>每转过一个链节，链速就重复一次<span style="color: black;">以上</span>变化，这种链速V时快时慢，V忽上忽下的变化，<span style="color: black;">叫作</span>为</span><span style="color: black;"><strong style="color: blue;"><span style="color: black;">链传动的多边形效应</span></strong>。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">链传动瞬时传动比是常数的前提<span style="color: black;">要求</span>是：</span></strong><span style="color: black;">轮齿数相同，链紧边长恰好为链节距的整数倍时，<span style="color: black;">便是</span>R1=R2，β，γ始终相<span style="color: black;">同期</span>，<strong style="color: blue;"><span style="color: black;">瞬时传动比才是常数</span></strong><strong style="color: blue;"><span style="color: black;">，主动轮角速度始终等于从动轮角速度。</span></strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">链传动中的动载荷</strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">链传动中的动载荷</span></strong><span style="color: black;"><span style="color: black;">包含</span><strong style="color: blue;"><span style="color: black;"><span style="color: black;">外边</span>附加动载荷</span></strong>与<strong style="color: blue;"><span style="color: black;">内部附加动载荷。</span></strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;"><span style="color: black;">外边</span>附加动载荷</span></strong><span style="color: black;">是<span style="color: black;">因为</span>工作载荷和原动机的工作特性带来的振动冲击等<span style="color: black;">原因</span><span style="color: black;">导致</span>的附加载荷，这种动载荷在工作<span style="color: black;">状况</span>系数中加以<span style="color: black;">思虑</span>。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">内部附加动载荷，</span></strong><span style="color: black;">由下列<span style="color: black;">原因</span>产生：</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">1.链的转速越高，节距越大，链的加速度越大，则链传动的动载荷<span style="color: black;">亦</span>越大。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">2.链的横向速度v(垂直于链条前进方向运动速度)周期性变化，会产生链传动的横向振动，这种横向振动是链传动动载荷中很重要的一部分，<span style="color: black;">亦</span>是<span style="color: black;">导致</span>共振的<span style="color: black;">重点</span><span style="color: black;">原由</span>。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">3.当链条的铰链与轮齿<span style="color: black;">忽然</span>啮合时相当于链节铰链敲击轮齿，<span style="color: black;">她们</span>之间会产生冲击动载荷。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">4.链和链轮的制造误差，以及安装误差</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">5.<span style="color: black;">因为</span>链条的松弛在<span style="color: black;">起步</span>，制动，反转，<span style="color: black;">忽然</span>超载或卸载<span style="color: black;">状况</span>下<span style="color: black;">显现</span>的惯性冲击等。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">因为</span><span style="color: black;">以上</span><span style="color: black;">原由</span>产生的动载荷都将<span style="color: black;">增多</span>功率损耗，降低链传动的寿命，<span style="color: black;">导致</span>过大的噪声。<span style="color: black;">因此呢</span>在设计中，<span style="color: black;">恰当</span>的<span style="color: black;">选取</span>参数，应</span><strong style="color: blue;"><span style="color: black;"><span style="color: black;">运用</span>较小的链节距，较多的链轮齿数（齿数少的话，在包角不变时，<span style="color: black;">每一个</span>齿承担的载荷增大，降低寿命），多排链（多排链的承载能力，随排数的<span style="color: black;">增多</span>而增大，但限于链条的制造与装配精度，各排链承受的载荷<span style="color: black;">很难</span><span style="color: black;">掌控</span>均匀，故排数不宜<span style="color: black;">太多</span>）等<span style="color: black;">办法</span>，来</span></strong><span style="color: black;"><strong style="color: blue;"><span style="color: black;">降低链传动中的动载荷。</span></strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">滚子传动链的<span style="color: black;">重点</span>失效形式</strong></span></p><strong style="color: blue;"><span style="color: black;">1、</span>铰链磨损</strong>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">（低速轻载）（开式）</span></strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">铰链磨损<span style="color: black;">重点</span><span style="color: black;">显现</span>于低速轻载中。</span></strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">链节在进入和退出啮合时，销轴与套筒之间存在相对滑动，在<span style="color: black;">不可</span><span style="color: black;">保准</span>充分润滑的<span style="color: black;">要求</span>下，将<span style="color: black;">导致</span>铰链的过度磨损，<span style="color: black;">引起</span>链轮节圆增大，链与链轮的啮合点外移，<span style="color: black;">最后</span>产生跳齿或脱齿而使传动失效（大齿轮先<span style="color: black;">出现</span>跳齿），磨损<span style="color: black;">重点</span>表<span style="color: black;">此刻</span>外链节截距的变化上，内链接截距的变化很小，因而<span style="color: black;">实质</span>铰链节距的不均匀性增大，使传动更不<span style="color: black;">安稳</span>，它<strong style="color: blue;"><span style="color: black;">是开式链传动的<span style="color: black;">重点</span>失效形式之一</span></strong></span></p><strong style="color: blue;"><span style="color: black;">2、</span>链板的疲劳破坏</strong>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">内链板外链板均会<span style="color: black;">出现</span>，<span style="color: black;">因为</span><strong style="color: blue;"><span style="color: black;">链在运动过程中受的载荷<span style="color: black;">持续</span>变化</span></strong>，因而链板在变应力状态下工作经过<span style="color: black;">必定</span>的循环次数后，链板会产生疲劳断裂。</span></p><strong style="color: blue;"><span style="color: black;">3、</span>点蚀和多次冲击破坏</strong>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">工作中<span style="color: black;">因为</span>链条反复<span style="color: black;">起步</span>，制动，反转或重复受冲击载荷时承受<span style="color: black;">很强</span>的动载荷，经<span style="color: black;">太多</span>次冲击，滚子表面产生点蚀，且滚子，套筒和销轴之间会产生冲击断裂。</span></p><strong style="color: blue;"><span style="color: black;">4、</span>销轴与套筒的胶合</strong>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">（高速重载且润滑<span style="color: black;">欠好</span>）</span></strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">重点</span><span style="color: black;">出现</span>在高速重载且润滑<span style="color: black;">欠好</span>的<span style="color: black;">状况</span>下，<span style="color: black;">因为</span>套筒和销轴之间存在相对运动，在变载荷的<span style="color: black;">功效</span>下，润滑油膜难以形成，当转速过高时，套筒与销轴间产生的热量，<span style="color: black;">引起</span>套筒与销轴的胶合失效，胶合限制了链传动的极限转速</span></p><strong style="color: blue;"><span style="color: black;">5、</span>过载拉断</strong>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">（低速重载或短时剧烈过载）</span></strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">在低速重载的传动中，<span style="color: black;">或</span>链传动严重过载时，链元件被拉断。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">滚子链传动的<span style="color: black;">重点</span>参数<span style="color: black;">选取</span></strong></span></p><strong style="color: blue;"><span style="color: black;">1、</span>链轮齿数</strong>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">小链轮齿数不宜<span style="color: black;">太多</span>或过少。</span></strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">当小链轮齿数太少时</span></strong><span style="color: black;">，运动速度的不均匀性和动载荷会很大，链节在进入和退出啮合时相对转角增大，销轴与套筒的磨损<span style="color: black;">增多</span>，链与链轮的冲击能量，链的拉力都相应的<span style="color: black;">加强</span>。因而传动的功率损耗<span style="color: black;">亦</span>随之<span style="color: black;">加强</span>。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;"><span style="color: black;">然则</span>小链轮齿数<span style="color: black;">亦</span><span style="color: black;">不可</span>太多</span></strong><span style="color: black;">，在速比不变的<span style="color: black;">要求</span>下，小链轮齿数<span style="color: black;">太多</span>时，大链轮的齿数<span style="color: black;">亦</span>随之<span style="color: black;">增加</span>，传动的尺寸和重量<span style="color: black;">亦</span>随之增大，<span style="color: black;">况且</span>齿数<span style="color: black;">太多</span>时，<span style="color: black;">因为</span>链的磨损使链节距增大，<span style="color: black;">更易</span>在大链轮上<span style="color: black;">出现</span>跳齿或脱链的现象。</span><span style="color: black;"><span style="color: black;">因为</span>链节数常取偶数，<span style="color: black;">因此</span>链轮指数<span style="color: black;">一般</span>应取为奇数，以使磨损均匀。</span></p><strong style="color: blue;"><span style="color: black;">2、</span>确定链接距和排数</strong>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">在<span style="color: black;">保准</span>链传动有足够的承载能力的<span style="color: black;">状况</span>下，为了减小震动冲击和噪声设计时，应<strong style="color: blue;"><span style="color: black;"><span style="color: black;">尽可能</span><span style="color: black;">选择</span>小的链节距。</span></strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">在<strong style="color: blue;"><span style="color: black;">高速重载</span></strong>时宜用小排距，小节距，多排链；</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">低速重载</span></strong></span><span style="color: black;">时，应用大节距，排数较少的链。</span></p><strong style="color: blue;"><span style="color: black;">3、</span>确定中心距和链节数</strong>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">中心距的<span style="color: black;">体积</span>对传动有很大的影响。中心距小时链节数少，链速一<span style="color: black;">按时</span>，单位时间内每一链节的应力变化次数和屈伸次数<span style="color: black;">增加</span>。<span style="color: black;">因此呢</span>链的疲劳和磨损<span style="color: black;">增多</span>。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">中心距大时</span></strong><span style="color: black;">链接节<span style="color: black;">增加</span>，吸震能力高，<span style="color: black;">运用</span>寿命长，</span><strong style="color: blue;"><span style="color: black;">但中心距太大时</span></strong><span style="color: black;">，又会<span style="color: black;">出现</span>链松边的颤抖现象，使运动的<span style="color: black;">安稳</span>性降低。</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">链传动的张紧</strong></span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">链传动张紧的目的，<span style="color: black;">重点</span>是为了避免链的垂度过大，啮合时链条上下颤抖，<span style="color: black;">同期</span><span style="color: black;">亦</span>可<span style="color: black;">增多</span>啮合包角，<span style="color: black;">一般</span>用的<strong style="color: blue;"><span style="color: black;">张紧<span style="color: black;">办法</span></span></strong>有：</span></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">1.靠<span style="color: black;">调节</span>中心距<span style="color: black;">掌控</span>张紧程度</span></strong></p>
<p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">2.附加张紧<span style="color: black;">安装</span>。</span></strong><span style="color: black;"><span style="color: black;">其中</span>心距不可调时可安装张紧轮，张紧轮<span style="color: black;">通常</span>压在松边靠近小轮外侧处。张紧轮<span style="color: black;">能够</span>是链轮，<span style="color: black;">亦</span><span style="color: black;">能够</span>是无齿的滚轮，其<span style="color: black;">体积</span>应与小链轮接近。</span></p>
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