说明门机台车轮啃轨的原因及排除方法。
参考答案：
故障原因：（1）车轮水平偏斜；（2）轨道偏差过大；（3）车轮的跨度或对角线超差；（4）各台车制动器调整不同；（5）各台车传动齿轮间隙不同；行走轮直径磨损不一。
排除方法：（1）检查轨道、行走轮、台车与门腿连接铰点、行走传动齿轮、联轴节等状况，若偏差较大，则逐项维修；（2）调整制动器，检换胶圈；（3）可以通过调整车轮来解决啃轨。由于主动轮与一整套传动机构连接，所以调整工作量较大，为此尽量调整被动车轮。调整前，先用千斤顶将端梁顶起，使车轮悬空，然后松开紧固螺栓进行调整。
(2013·高考四川卷)“Look，it’s Baldy！”A boy shouted in my direction across the playground.Even though I was used to regular insults(侮辱) because of the___on my head，it was___horrible to hear.I sighed as I headed back to the class. When I was just 20 months old，I suffered serious____after a bowl full of hot oil fell on my head.I was____to hospital and had to stay there for weeks while the doctors____to save my life.“Holly’s very____to be alive，”they told Mum and Dad.“But she’ll be___with scars on her head，and of course her hair won’t grow there.” As a child，I cared much about my scars，so I____wore a scarf to cover them up when I left home.____I didn’t，people would call me horrible names like Baldy.Although my friends were always comforting me，they never____understood how it felt. Then through the hospital I was____to a children’s burns camp，where children like me can get any help.There，I____14yearold Stephanie，whose burns are a lot more serious than mine.But she is so____that she never lets anyone put her down.“You shouldn’t____what people say about what you look like because we’re not different from anyone else，Holly，”she____me.“And you don’t need to wear a scarf because you look great____it！” For the first time in my life I could speak to someone who’d been through something____.So weeks later，at my 13th birthday party，____by her bravery，I gave up my scarf and showed off my scars.It felt amazing not having to____away behind my scarf. Now，I am____of what I look like and much happier，because I have realized it is your personality(个性)that decides who you truly are.
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