1、 軸(zhou)承(cheng)疲(pi)勞(lao)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)的(de)(de)(de)(de)(de)基本概念 一(yi)(yi)般意義的(de)(de)(de)(de)(de)軸(zhou)承(cheng)疲(pi)勞(lao)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)是(shi)指一(yi)(yi)定技術狀態下(結構、工(gong)藝狀態、配合、安(an)裝、游(you)隙和潤滑(hua)狀態等)的(de)(de)(de)(de)(de)滾動軸(zhou)承(cheng),在(zai)(zai)主機(ji)的(de)(de)(de)(de)(de)實(shi)際(ji)使(shi)用(yong)(yong)(yong)狀態下運轉(zhuan)(zhuan),直(zhi)至滾動表面發生疲(pi)勞(lao)而不能滿足主機(ji)要求時(shi)的(de)(de)(de)(de)(de)軸(zhou)承(cheng)內、外圈(軸(zhou)、座圈)相對旋轉(zhuan)(zhuan)次數(shu)(shu)的(de)(de)(de)(de)(de)總(zong)值(zhi)――總(zong)轉(zhuan)(zhuan)數(shu)(shu)。當軸(zhou)承(cheng)轉(zhuan)(zhuan)更(geng)大(da)致恒定或(huo)(huo)為已知,疲(pi)勞(lao)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)可用(yong)(yong)(yong)與總(zong)轉(zhuan)(zhuan)數(shu)(shu)相應的(de)(de)(de)(de)(de)運轉(zhuan)(zhuan)總(zong)小時(shi)數(shu)(shu)來(lai)(lai)表示(shi),此外,還應注意: 1、 影響軸(zhou)承(cheng)疲(pi)勞(lao)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)的(de)(de)(de)(de)(de)因(yin)(yin)素(su)非(fei)常多,無法全(quan)部加以估計(ji)或(huo)(huo)通過標(biao)準試驗條(tiao)件(jian)而加以消(xiao)除(chu),這造成(cheng)軸(zhou)承(cheng)實(shi)際(ji)疲(pi)勞(lao)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)有(you)很大(da)的(de)(de)(de)(de)(de)離散(san)性,因(yin)(yin)此軸(zhou)承(cheng)疲(pi)勞(lao)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)的(de)(de)(de)(de)(de)表達(da)參數(shu)(shu)為額定壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)L10,在(zai)(zai)ISO推薦標(biao)準R281中(zhong)對L10的(de)(de)(de)(de)(de)涵義明(ming)確規定如(ru)下: “數(shu)(shu)量上足夠(gou)多的(de)(de)(de)(de)(de)相同的(de)(de)(de)(de)(de)一(yi)(yi)批(pi)軸(zhou)承(cheng),其額定壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)L10用(yong)(yong)(yong)轉(zhuan)(zhuan)數(shu)(shu)(或(huo)(huo)在(zai)(zai)轉(zhuan)(zhuan)速(su)不變時(shi)用(yong)(yong)(yong)小時(shi)數(shu)(shu)來(lai)(lai)表示(shi),該(gai)批(pi)軸(zhou)承(cheng)中(zhong)有(you)90%在(zai)(zai)疲(pi)勞(lao)剝落發生前能達(da)到或(huo)(huo)超過此轉(zhuan)(zhuan)數(shu)(shu)(或(huo)(huo)小時(shi)數(shu)(shu))”。迄今為止,世界各國都(dou)遵(zun)從上述規定。 在(zai)(zai)美國等一(yi)(yi)些國家中(zhong),還用(yong)(yong)(yong)用(yong)(yong)(yong)中(zhong)值(zhi)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)的(de)(de)(de)(de)(de)概念。中(zhong)值(zhi)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)LM是(shi)指一(yi)(yi)批(pi)相同軸(zhou)承(cheng)的(de)(de)(de)(de)(de)中(zhong)值(zhi)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming),即指其中(zhong)50%的(de)(de)(de)(de)(de)軸(zhou)承(cheng)在(zai)(zai)疲(pi)勞(lao)剝落前能夠(gou)達(da)到或(huo)(huo)超過總(zong)轉(zhuan)(zhuan)數(shu)(shu),或(huo)(huo)在(zai)(zai)一(yi)(yi)定轉(zhuan)(zhuan)速(su)下的(de)(de)(de)(de)(de)工(gong)作不時(shi)數(shu)(shu),中(zhong)值(zhi)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)LM不是(shi)一(yi)(yi)批(pi)軸(zhou)承(cheng)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)的(de)(de)(de)(de)(de)算術平均(jun)值(zhi)。一(yi)(yi)般中(zhong)值(zhi)壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)LM是(shi)額定壽(shou)(shou)(shou)(shou)(shou)命(ming)(ming)(ming)(ming)的(de)(de)(de)(de)(de)5倍左右。
2、 額定壽(shou)(shou)命(ming)(ming)(ming)的(de)(de)(de)(de)(de)概念只適用(yong)(yong)于數(shu)量足(zu)(zu)夠(gou)的(de)(de)(de)(de)(de)一批軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng),而(er)不(bu)適用(yong)(yong)于個(ge)別軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)。 例如有40套6204軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)按(an)(an)(an)其(qi)(qi)使(shi)用(yong)(yong)條算(suan)(suan)(suan)得(de)其(qi)(qi)額定壽(shou)(shou)命(ming)(ming)(ming)為(wei)(wei)1000h而(er)不(bu)致發(fa)(fa)生疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)破壞,其(qi)(qi)余(yu)的(de)(de)(de)(de)(de)4套則(ze)可(ke)能不(bu)到1000h即出現疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)失效的(de)(de)(de)(de)(de)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng),額定疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)的(de)(de)(de)(de)(de)意(yi)義(yi)就代(dai)表這批軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)在(zai)正常發(fa)(fa)揮(hui)其(qi)(qi)材料潛力時(shi)可(ke)期望(wang)的(de)(de)(de)(de)(de)壽(shou)(shou)命(ming)(ming)(ming)。因此在(zai)大(da)(da)多(duo)數(shu)情況(kuang)(kuang)下(xia),用(yong)(yong)戶(hu)在(zai)選擇軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)時(shi)仍(reng)先作疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)計(ji)(ji)(ji)(ji)(ji)算(suan)(suan)(suan),再根據(ju)實(shi)際(ji)失效類別進(jin)行校核,例如磨(mo)損壽(shou)(shou)命(ming)(ming)(ming)校核,取(qu)(qu)計(ji)(ji)(ji)(ji)(ji)算(suan)(suan)(suan)結果中(zhong)的(de)(de)(de)(de)(de)較(jiao)小值為(wei)(wei)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)計(ji)(ji)(ji)(ji)(ji)算(suan)(suan)(suan)壽(shou)(shou)命(ming)(ming)(ming)。 二、 軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)的(de)(de)(de)(de)(de)估(gu)(gu)計(ji)(ji)(ji)(ji)(ji)方(fang)(fang)(fang)法(fa)(fa) 軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)的(de)(de)(de)(de)(de)估(gu)(gu)計(ji)(ji)(ji)(ji)(ji)方(fang)(fang)(fang)法(fa)(fa)有計(ji)(ji)(ji)(ji)(ji)算(suan)(suan)(suan)方(fang)(fang)(fang)法(fa)(fa)和(he)(he)試(shi)(shi)驗(yan)(yan)(yan)湛支兩種(zhong)。 按(an)(an)(an)規(gui)定公式(shi)和(he)(he)計(ji)(ji)(ji)(ji)(ji)算(suan)(suan)(suan)規(gui)則(ze)計(ji)(ji)(ji)(ji)(ji)算(suan)(suan)(suan)出來的(de)(de)(de)(de)(de)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)作為(wei)(wei)計(ji)(ji)(ji)(ji)(ji)算(suan)(suan)(suan)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming),所(suo)算(suan)(suan)(suan)出總轉(zhuan)數(shu)值規(gui)定為(wei)(wei)內圈(quan)或軸(zhou)(zhou)(zhou)(zhou)圈(quan)轉(zhuan)動(dong)(此時(shi)外圈(quan)或座圈(quan)為(wei)(wei)固定)時(shi)的(de)(de)(de)(de)(de)總轉(zhuan)數(shu)值。 按(an)(an)(an)照我國規(gui)定的(de)(de)(de)(de)(de)標準(zhun)試(shi)(shi)驗(yan)(yan)(yan)方(fang)(fang)(fang)法(fa)(fa)(ZQ 12-94)滾(gun)動(dong)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)試(shi)(shi)驗(yan)(yan)(yan)規(gui)程(cheng)),在(zai)使(shi)用(yong)(yong)性(xing)能上(shang)(shang)能滿足(zu)(zu)為(wei)(wei)一方(fang)(fang)(fang)法(fa)(fa)所(suo)規(gui)定各項要(yao)求的(de)(de)(de)(de)(de)試(shi)(shi)驗(yan)(yan)(yan)機,對(dui)一批軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)進(jin)行抽樣疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)試(shi)(shi)驗(yan)(yan)(yan),從試(shi)(shi)驗(yan)(yan)(yan)數(shu)據(ju)處理中(zhong)得(de)到的(de)(de)(de)(de)(de)實(shi)際(ji)試(shi)(shi)驗(yan)(yan)(yan)壽(shou)(shou)命(ming)(ming)(ming),即為(wei)(wei)被試(shi)(shi)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)所(suo)代(dai)表的(de)(de)(de)(de)(de)該批軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)的(de)(de)(de)(de)(de)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)試(shi)(shi)驗(yan)(yan)(yan)壽(shou)(shou)命(ming)(ming)(ming)。 滾(gun)動(dong)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)試(shi)(shi)驗(yan)(yan)(yan)裨上(shang)(shang)是(shi)充(chong)分(fen)的(de)(de)(de)(de)(de)潤滑最大(da)(da)限(xian)度地抑制滾(gun)動(dong)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)的(de)(de)(de)(de)(de)磨(mo)損因素,采用(yong)(yong)強化(hua)的(de)(de)(de)(de)(de)負荷與轉(zhuan)速以(yi)突出軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)因素的(de)(de)(de)(de)(de)一種(zhong)強化(hua)的(de)(de)(de)(de)(de)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)試(shi)(shi)驗(yan)(yan)(yan)方(fang)(fang)(fang)法(fa)(fa)。 軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)的(de)(de)(de)(de)(de)計(ji)(ji)(ji)(ji)(ji)算(suan)(suan)(suan)法(fa)(fa)和(he)(he)疲(pi)(pi)(pi)(pi)勞(lao)(lao)(lao)(lao)(lao)壽(shou)(shou)命(ming)(ming)(ming)試(shi)(shi)驗(yan)(yan)(yan)是(shi)相(xiang)輔相(xiang)成的(de)(de)(de)(de)(de),二者所(suo)得(de)的(de)(de)(de)(de)(de)結果有足(zu)(zu)夠(gou)的(de)(de)(de)(de)(de)對(dui)應性(xing)。 事實(shi)上(shang)(shang),如對(dui)每一個(ge)特定的(de)(de)(de)(de)(de)使(shi)用(yong)(yong)場合,都(dou)抽取(qu)(qu)足(zu)(zu)夠(gou)數(shu)量的(de)(de)(de)(de)(de)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)進(jin)行壽(shou)(shou)命(ming)(ming)(ming)試(shi)(shi)驗(yan)(yan)(yan),以(yi)驗(yan)(yan)(yan)證所(suo)選軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)是(shi)否合適,這在(zai)經濟上(shang)(shang)、時(shi)間上(shang)(shang)和(he)(he)勞(lao)(lao)(lao)(lao)(lao)動(dong)量上(shang)(shang)都(dou)是(shi)十分(fen)浩大(da)(da)的(de)(de)(de)(de)(de),所(suo)以(yi)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)壽(shou)(shou)命(ming)(ming)(ming)的(de)(de)(de)(de)(de)試(shi)(shi)驗(yan)(yan)(yan)方(fang)(fang)(fang)法(fa)(fa)只是(shi)在(zai)十分(fen)必(bi)要(yao)或重要(yao)的(de)(de)(de)(de)(de)情況(kuang)(kuang)下(xia)才(cai)使(shi)用(yong)(yong),在(zai)絕大(da)(da)多(duo)數(shu)情況(kuang)(kuang)下(xia),采用(yong)(yong)標準(zhun)的(de)(de)(de)(de)(de)壽(shou)(shou)命(ming)(ming)(ming)計(ji)(ji)(ji)(ji)(ji)算(suan)(suan)(suan)方(fang)(fang)(fang)法(fa)(fa)來估(gu)(gu)計(ji)(ji)(ji)(ji)(ji)軸(zhou)(zhou)(zhou)(zhou)承(cheng)(cheng)(cheng)的(de)(de)(de)(de)(de)使(shi)用(yong)(yong)壽(shou)(shou)命(ming)(ming)(ming),有著足(zu)(zu)夠(gou)程(cheng)度的(de)(de)(de)(de)(de)可(ke)依(yi)賴性(xing)。