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随(sui)着智能(neng)家(jia)居的(de)(de)(de)兴(xing)起与发展,以自(zi)(zi)动感(gan)知(zhi)、智能(neng)控制(zhi)、自(zi)(zi)动执(zhi)行(xing)为特征(zheng)的(de)(de)(de)智能(neng)家(jia)电(dian)(dian)成(cheng)为行(xing)业发展的(de)(de)(de)趋势,而直(zhi)流电(dian)(dian)机(ji)作(zuo)为最重要的(de)(de)(de)自(zi)(zi)动控制(zhi)执(zhi)行(xing)器之一(yi),开(kai)始(shi)在智能(neng)家(jia)电(dian)(dian)和(he)(he)智能(neng)厨电(dian)(dian)中被广(guang)泛使(shi)用(yong)。然而,厨电(dian)(dian)中使(shi)用(yong)的(de)(de)(de)直(zhi)流电(dian)(dian)机(ji),长期工作(zuo)在高温、潮湿、多(duo)盐等腐(fu)蚀性(xing)物质的(de)(de)(de)环境(jing)中,再加上其频繁启停,直(zhi)流电(dian)(dian)机(ji)故障频发,成(cheng)为困扰智能(neng)家(jia)电(dian)(dian)生产厂商(shang)和(he)(he)用(yong)户(hu)的(de)(de)(de)一(yi)大(da)难题(ti)。直(zhi)流电(dian)(dian)机(ji)结构相对简单(dan),主要由磁瓦、换向器、电(dian)(dian)刷(shua)、绕组、刷(shua)架、轴承等零部件(jian)组成(cheng),各零部件(jian)常见失效模式。
电刷失效机理分析:
1、直流(liu)电(dian)(dian)机(ji)运转过(guo)程中,电(dian)(dian)刷在电(dian)(dian)流(liu)通过(guo)下不断摩(mo)擦磨(mo)(mo)(mo)损(sun),是典型的(de)载流(liu)摩(mo)擦磨(mo)(mo)(mo)损(sun)过(guo)程。由(you)于(yu)电(dian)(dian)场、电(dian)(dian)流(liu)及电(dian)(dian)弧等(deng)电(dian)(dian)因素介(jie)入到摩(mo)擦系统中,再加(jia)上湿(shi)热、盐(yan)雾对润滑、腐(fu)(fu)蚀等(deng)因素的(de)耦(ou)合,电(dian)(dian)刷的(de)腐(fu)(fu)蚀磨(mo)(mo)(mo)损(sun)存在粘着磨(mo)(mo)(mo)损(sun)、磨(mo)(mo)(mo)粒磨(mo)(mo)(mo)损(sun)、氧化磨(mo)(mo)(mo)损(sun)、腐(fu)(fu)蚀磨(mo)(mo)(mo)损(sun)、疲(pi)劳(lao)磨(mo)(mo)(mo)损(sun)、电(dian)(dian)弧烧蚀等(deng)多种不同机(ji)理(li)。
2、随着电(dian)(dian)(dian)(dian)刷(shua)(shua)与(yu)换(huan)(huan)(huan)向器运动(dong)摩擦(ca),摩擦(ca)副(fu)表面(mian)材料(liao)温度升高,材料(liao)微观区(qu)域表面(mian)发(fa)生塑(su)性(xing)变形,摩擦(ca)阻(zu)(zu)力增大,进(jin)而产生粘(zhan)着磨损(sun),并(bing)伴(ban)有(you)磨粒磨损(sun)。电(dian)(dian)(dian)(dian)刷(shua)(shua)与(yu)换(huan)(huan)(huan)向器之(zhi)间有(you)电(dian)(dian)(dian)(dian)流通过(guo),其(qi)接触(chu)表面(mian)除机械摩擦(ca)之(zhi)外,还由(you)接触(chu)电(dian)(dian)(dian)(dian)阻(zu)(zu)产生大量(liang)热量(liang),进(jin)一步加(jia)剧了电(dian)(dian)(dian)(dian)刷(shua)(shua)的粘(zhan)着磨损(sun)。再加(jia)上电(dian)(dian)(dian)(dian)刷(shua)(shua)在脱离(li)换(huan)(huan)(huan)向器瞬(shun)间会(hui)产生电(dian)(dian)(dian)(dian)弧,电(dian)(dian)(dian)(dian)弧侵蚀造成(cheng)电(dian)(dian)(dian)(dian)刷(shua)(shua)材料(liao)的融化、气(qi)化和喷(pen)溅(jian),既造成(cheng)材料(liao)的直接消(xiao)耗(hao),又使得(de)电(dian)(dian)(dian)(dian)刷(shua)(shua)换(huan)(huan)(huan)向器之(zhi)间接触(chu)电(dian)(dian)(dian)(dian)阻(zu)(zu)增大,生成(cheng)更多热量(liang)。
3、而在盐雾和湿热(re)环(huan)境条(tiao)件下,盐溶(rong)液粘附在电刷(shua)表面(mian)、形成电解(jie)质液膜(mo),电刷(shua)材料为(wei)金属铜(tong)合金,非常活(huo)泼,生成电化学(xue)反应,腐(fu)蚀效果明显。再加上(shang)换(huan)向器(qi)和电刷(shua)之(zhi)间的电场作用(yong),电化学(xue)反应速度更快,对电刷(shua)的腐(fu)蚀磨损作用(yong)更大。
4、由于(yu)载流(liu)摩擦磨(mo)损(sun)和电(dian)(dian)化学(xue)腐(fu)蚀的(de)耦合(he)作(zuo)用(yong),盐(yan)雾(wu)+潮热环境条件下的(de)直流(liu)电(dian)(dian)机电(dian)(dian)刷(shua)腐(fu)蚀磨(mo)损(sun)速(su)度远超单一(yi)(yi)机理下的(de)磨(mo)损(sun),并且该腐(fu)蚀磨(mo)损(sun)过程(cheng)是一(yi)(yi)个恶性循环过程(cheng),电(dian)(dian)刷(shua)磨(mo)损(sun)速(su)率越来越快,
5、有(you)刷(shua)直(zhi)(zhi)流电机(ji)(ji)具有(you)成本(ben)低、调速性能好、控制简(jian)单等几乎(hu)一切优点,唯(wei)一的缺点就是(shi)不耐用(yong),寿命(ming)相较其他类型电机(ji)(ji)较短。主要原因是(shi)由于(yu)有(you)刷(shua)直(zhi)(zhi)流电机(ji)(ji)的电刷(shua)与换(huan)(huan)向(xiang)器在换(huan)(huan)向(xiang)过程中不可避免发生剧烈(lie)腐蚀(shi)磨(mo)损,从而(er)限制直(zhi)(zhi)流电机(ji)(ji)寿命(ming)与使(shi)用(yong)次数。
为应(ying)对上述(shu)情况,无(wu)刷直流(liu)电(dian)(dian)(dian)(dian)机得到快速发展,通过电(dian)(dian)(dian)(dian)路(lu)控(kong)制取代(dai)电(dian)(dian)(dian)(dian)刷换向,可有效地将直流(liu)电(dian)(dian)(dian)(dian)机寿(shou)命(ming)提高(gao)十几倍以上,与有刷直流(liu)电(dian)(dian)(dian)(dian)机一(yi)起,广泛应(ying)用于自(zi)动(dong)控(kong)制、仪器仪表、医疗器械、家电(dian)(dian)(dian)(dian)、武器装备(bei)等各领域。