直齒輪是指輪緣上有齒輪持續嚙合通報活動和能源的機器元件。齒輪在傳動中的操縱很早就呈現了。19世紀末，展成切齒法的道理及操縱此道理切齒的公用機床與刀具的接踵呈現，跟著出產的成長，齒輪運行的安穩性遭到正視。

變(bian)位(wei)系(xi)(xi)數(shu)是(shi)草(cao)案齒(chi)(chi)(chi)變(bian)大的身分。傘(san)齒(chi)(chi)(chi)變(bian)位(wei)系(xi)(xi)數(shu)被界說為(wei)變(bian)位(wei)系(xi)(xi)數(shu)制輪(lun)齒(chi)(chi)(chi)的1個基石運作，是(shi)稿(gao)酬廣泛粗來(lai)從而身旁輪(lun)齒(chi)(chi)(chi)的規模的數(shu)。總體目標(biao)是(shi)正(zheng)規起(qi)來(lai)化傘(san)齒(chi)(chi)(chi)數(shu)控(kong)刀，減少掙錢。直齒(chi)(chi)(chi)、斜齒(chi)(chi)(chi)和錐(zhui)體齒(chi)(chi)(chi)傘(san)齒(chi)(chi)(chi)的變(bian)位(wei)系(xi)(xi)數(shu)皆可參閱正(zheng)規起(qi)來(lai)變(bian)位(wei)系(xi)(xi)數(shu)系(xi)(xi)列的表。

跟著(zhu)我制造業發展(zhan)因素經常(chang)進步英(ying)語(yu)，設計的多(duo)(duo)量量盛產齒軸良多(duo)(duo)都進行(xing)料框(kuang)的變位(wei)系(xi)數，使其意味被虛化(hua)。

即使傘(san)齒(chi)(chi)(chi)(chi)(chi)的(de)(de)齒(chi)(chi)(chi)(chi)(chi)數(shu)不可避免，系(xi)(xi)(xi)(xi)數(shu)越愈大(da)輪的(de)(de)徑(jing)向規格(ge)尺寸也(ye)越大(da)。系(xi)(xi)(xi)(xi)數(shu)系(xi)(xi)(xi)(xi)列作(zuo)品(pin)正(zheng)確了(le)是通(tong)過工(gong)作(zuo)指導(dao)思想、定制(zhi)和(he)查檢等(deng)中(zhong)請設定的(de)(de)。對應具非(fei)直齒(chi)(chi)(chi)(chi)(chi)的(de)(de)傘(san)齒(chi)(chi)(chi)(chi)(chi)，系(xi)(xi)(xi)(xi)數(shu)有(you)法向系(xi)(xi)(xi)(xi)數(shu)mn、橫(heng)截系(xi)(xi)(xi)(xi)數(shu)ms與軸徑(jing)系(xi)(xi)(xi)(xi)數(shu)mx的(de)(de)分，我(wo)們都(dou)因每個人(ren)的(de)(de)齒(chi)(chi)(chi)(chi)(chi)距(ju)(法向齒(chi)(chi)(chi)(chi)(chi)距(ju)、橫(heng)截齒(chi)(chi)(chi)(chi)(chi)距(ju)與軸徑(jing)齒(chi)(chi)(chi)(chi)(chi)距(ju))與圓上(shang)率的(de)(de)比率，也(ye)都(dou)以(yi)mm毫米為標段。對錐傘(san)齒(chi)(chi)(chi)(chi)(chi)，系(xi)(xi)(xi)(xi)數(shu)有(you)個端系(xi)(xi)(xi)(xi)數(shu)me、豎直系(xi)(xi)(xi)(xi)數(shu)mm和(he)小端系(xi)(xi)(xi)(xi)數(shu)m1之分。對加(jia)工(gong)件，則有(you)卡死的(de)(de)加(jia)工(gong)件系(xi)(xi)(xi)(xi)數(shu)等(deng)。正(zheng)確了(le)系(xi)(xi)(xi)(xi)數(shu)的(de)(de)支配很廣(guang)。在公制(zhi)的(de)(de)傘(san)齒(chi)(chi)(chi)(chi)(chi)傳(chuan)(chuan)送(song)(song)、蝸桿傳(chuan)(chuan)送(song)(song)、云(yun)同步齒(chi)(chi)(chi)(chi)(chi)形帶傳(chuan)(chuan)送(song)(song)和(he)棘輪、傘(san)齒(chi)(chi)(chi)(chi)(chi)連(lian)軸器、花鍵等(deng)機(ji)床(chuang)中(zhong)，正(zheng)確了(le)系(xi)(xi)(xi)(xi)數(shu)全都(dou)是某(mou)項最根據的(de)(de)叁數(shu)。它對以(yi)上(shang)所(suo)述(shu)機(ji)床(chuang)的(de)(de)工(gong)作(zuo)指導(dao)思想、定制(zhi)、修理等(deng)都(dou)起(qi)著根據叁數(shu)的(de)(de)影響(xiang)(見圓柱體傘(san)齒(chi)(chi)(chi)(chi)(chi)傳(chuan)(chuan)送(song)(song)、蝸桿傳(chuan)(chuan)送(song)(song)等(deng))。