行星(xing)減速機中行(xing)(xing)星(xing)齒(chi)(chi)輪(lun)傳動(dong)(dong)與普通齒(chi)(chi)輪(lun)傳動(dong)(dong)相(xiang)比(bi)，具有(you)許多獨(du)特優(you)點(dian)。最(zui)顯(xian)著的(de)特點(dian)是在(zai)(zai)傳遞動(dong)(dong)力時可以(yi)進(jin)行(xing)(xing)功率分流(liu)，并且輸入(ru)軸和(he)輸出軸處(chu)在(zai)(zai)同(tong)一水平線上。所以(yi)行(xing)(xing)星(xing)齒(chi)(chi)輪(lun)傳動(dong)(dong)結構現已被廣泛(fan)應用于各(ge)種機械(xie)傳動(dong)(dong)系統(tong)中的(de)減速(su)(su)機、增速(su)(su)器和(he)變速(su)(su)裝置(zhi)。

簡單的行星齒輪傳動結構都由兩排或三排以上行星齒輪機構組成，包括一個太陽輪、若干個行星齒輪和一個齒輪圈，其中行星齒輪由行星架的固定軸支承，允許行星輪在支承軸上轉動。行星齒輪和相鄰的太陽輪、齒圈總是處于常嚙合狀態，所以斜齒輪減(jian)速機(ji)相(xiang)比(bi)之(zhi)下有更高(gao)的平穩性。

行(xing)(xing)(xing)星(xing)齒輪(lun)(lun)(lun)傳(chuan)(chuan)動(dong)(dong)結構中(zhong)，位(wei)(wei)于(yu)(yu)行(xing)(xing)(xing)星(xing)齒輪(lun)(lun)(lun)機(ji)構中(zhong)心(xin)的(de)(de)是太陽(yang)輪(lun)(lun)(lun)，太陽(yang)輪(lun)(lun)(lun)和(he)行(xing)(xing)(xing)星(xing)輪(lun)(lun)(lun)常嚙(nie)合(he)，兩(liang)個外(wai)齒輪(lun)(lun)(lun)嚙(nie)合(he)旋轉方(fang)向相反。正如太陽(yang)位(wei)(wei)于(yu)(yu)太陽(yang)系的(de)(de)中(zhong)心(xin)一(yi)樣，太陽(yang)輪(lun)(lun)(lun)也因其位(wei)(wei)置而得名。在整個行(xing)(xing)(xing)星(xing)齒輪(lun)(lun)(lun)傳(chuan)(chuan)動(dong)(dong)結構中(zhong)，如行(xing)(xing)(xing)星(xing)輪(lun)(lun)(lun)的(de)(de)自轉存(cun)在，而行(xing)(xing)(xing)星(xing)架(jia)則固定(ding)不動(dong)(dong)，這種方(fang)式(shi)類似平(ping)行(xing)(xing)(xing)軸式(shi)的(de)(de)傳(chuan)(chuan)動(dong)(dong)稱(cheng)為(wei)定(ding)軸傳(chuan)(chuan)動(dong)(dong)。齒圈是內齒輪(lun)(lun)(lun)，它和(he)行(xing)(xing)(xing)星(xing)輪(lun)(lun)(lun)常嚙(nie)合(he)，是內齒和(he)外(wai)齒輪(lun)(lun)(lun)嚙(nie)合(he)，兩(liang)者間旋轉方(fang)向相同。行(xing)(xing)(xing)星(xing)齒輪(lun)(lun)(lun)的(de)(de)個數取決于(yu)(yu)變速器的(de)(de)設(she)計負荷，通常有三(san)個或四個，個數愈多(duo)承擔負荷愈大。