ZLY是(shi)(shi)硬齒(chi)面圓柱齒(chi)輪減(jian)速機(ji)，N是(shi)(shi)帶逆止器，125是(shi)(shi)中心距，20是(shi)(shi)速比，1是(shi)(shi)裝(zhuang)配形式。

減速機(ji)在原動機(ji)和工作機(ji)或執行機(ji)構(gou)之間起(qi)匹配轉速和傳遞轉矩的(de)作用(yong)，是一種相(xiang)對精密的(de)機(ji)械(xie)。

使用(yong)它的目(mu)的是降低轉速，增加(jia)轉矩(ju)。它的種(zhong)類(lei)繁多(duo)，型號各異，不同種(zhong)類(lei)有不同的用(yong)途。

減(jian)(jian)(jian)速器(qi)的種類繁多，按(an)照(zhao)傳(chuan)動類型可(ke)(ke)分(fen)為(wei)(wei)(wei)齒(chi)(chi)輪(lun)減(jian)(jian)(jian)速器(qi)、蝸桿(gan)減(jian)(jian)(jian)速器(qi)和行星齒(chi)(chi)輪(lun)減(jian)(jian)(jian)速器(qi)；按(an)照(zhao)傳(chuan)動級數不同可(ke)(ke)分(fen)為(wei)(wei)(wei)單級和多級減(jian)(jian)(jian)速器(qi)；按(an)照(zhao)齒(chi)(chi)輪(lun)形狀可(ke)(ke)分(fen)為(wei)(wei)(wei)圓(yuan)柱齒(chi)(chi)輪(lun)減(jian)(jian)(jian)速器(qi)、圓(yuan)錐(zhui)齒(chi)(chi)輪(lun)減(jian)(jian)(jian)速器(qi)和圓(yuan)錐(zhui)－圓(yuan)柱齒(chi)(chi)輪(lun)減(jian)(jian)(jian)速器(qi)；按(an)照(zhao)傳(chuan)動的布置形式又可(ke)(ke)分(fen)為(wei)(wei)(wei)展開式、分(fen)流式和同軸式減(jian)(jian)(jian)速器(qi)。