機(jī)械設(shè)計(jì)課程設(shè)計(jì)-在線瀏覽
2024-08-06 07:59本頁面
【正文】 （4）壓力角a = 20176。①試選載荷系數(shù)KHt = 。④由圖查取區(qū)域系數(shù)ZH = 。⑥計(jì)算接觸疲勞強(qiáng)度用重合度系數(shù)Zε 。/(22+21)] = 176。/(87+21)] = 176。tan20176。tan20176。計(jì)算應(yīng)力循環(huán)次數(shù)：小齒輪應(yīng)力循環(huán)次數(shù)：N1 = 60nkth = 6048011030028 = 109大齒輪應(yīng)力循環(huán)次數(shù)：N2 = 60nkth = N1/u = 109/ = 108查取接觸疲勞壽命系數(shù):KHN1 = 、KHN2 = 。②根據(jù)v = m/s、8級(jí)精度，由圖108查得動(dòng)載系數(shù)KV = 。④由表104用插值法查得8級(jí)精度、小齒輪相對(duì)支承非對(duì)稱布置時(shí)，KHb = 。（1）計(jì)算分度圓直徑d1 = z1m = 223 = 66 mmd2 = z2m = 833 = 249 mm（2）計(jì)算中心距a = (d1+d2)/2 = (66+249)/2 = mm（3）計(jì)算齒輪寬度b = φdd1 = 166 = 66 mm（1）齒根彎曲疲勞強(qiáng)度條件sF = ≤ [sF]1）確定公式中各參數(shù)值①計(jì)算彎曲疲勞強(qiáng)度用重合度系數(shù)YeYe = ++②由齒數(shù)，查圖得齒形系數(shù)和應(yīng)力修正系數(shù)YFa1 = YFa2 = YSa1 = YSa2 = ③計(jì)算實(shí)際載荷系數(shù)KF由表103查得齒間載荷分配系數(shù)KFa = 根據(jù)表104用插值法查得KHb = ，結(jié)合b/h = = 則載荷系數(shù)為KF = KAKvKFaKFb = 1 = ④計(jì)算齒根彎曲疲勞許用應(yīng)力[sF]查得小齒輪和大齒輪的彎曲疲勞極限分別為sFlim1 = 500 MPa、sFlim2 = 380 MPa。 齒數(shù)z1 = 2z2 = 87，模數(shù)m = 3 mm，壓力角a = 20176。代號(hào)名稱計(jì)算公式高速級(jí)小齒輪高速級(jí)大齒輪模數(shù)m3mm3mm齒數(shù)z2283齒寬b71mm66mm分度圓直徑d66mm249mm齒頂高系數(shù)ha頂隙系數(shù)c齒頂高h(yuǎn)amha3mm3mm齒根高h(yuǎn)fm(ha+c)全齒高h(yuǎn)ha+hf齒頂圓直徑dad+2ha72mm251mm齒根圓直徑dfd2hf（4輪的設(shè)計(jì)）、材料及齒數(shù)（1）選擇小齒輪材料為40Cr（調(diào)質(zhì)），齒面硬度280HBS，大齒輪材料為45鋼（調(diào)質(zhì)），齒面硬度為240HBS。（3）選小齒輪齒數(shù)z3 = 23，大齒輪齒數(shù)z4 = 23= ，取z4= 67。（1）由式試算小齒輪分度圓直徑，即1）確定公式中的各參數(shù)值。②計(jì)算小齒輪傳遞的轉(zhuǎn)矩T2 = 382N/m③選取齒寬系數(shù)φd = 1。⑤查表得材料的彈性影響系數(shù)ZE = MPa1/2。端面壓力角：aa1 = arccos[z3cosa/(z3+2ha*)] = arccos[23cos20176。aa2 = arccos[z4cosa/(z4+2ha*)] = arccos[67cos20176。端面重合度：ea = [z3(tanaa1tana)+z4(tanaa2tana)]/2π = [23(176。)+70(176。)]/2π = 重合度系數(shù)：Ze = = = ⑦計(jì)算接觸疲勞許用應(yīng)力[sH]查得小齒輪和大齒輪的接觸疲勞極限分別為sHlim1 = 600 MPa、sHlim2 = 550 MPa。取失效概率為1%,安全系數(shù)S=1,得:[sH]1 = = = 546 MPa[sH]2 = = = MPa取[sH]1和[sH]2中的較小者作為該齒輪副的接觸疲勞許用應(yīng)力，即[sH] = [sH]2 = MPa2）試算小齒輪分度圓直徑 = = （2）調(diào)整小齒輪分度圓直徑1）計(jì)算實(shí)際載荷系數(shù)前的數(shù)據(jù)準(zhǔn)備①圓周速度vv = = = m/s②齒寬bb = =1 = 2）計(jì)算實(shí)際載荷系數(shù)KH①由表查得使用系數(shù)KA = 1。③齒輪的圓周力Ft3 = 2T2/d1t = 21000382/= NKAFt3/b = 1 100 N/mm查表得齒間載荷分配系數(shù)KHa = 。由此，得到實(shí)際載荷系數(shù)KH = KAKVKHaKHb = 1 = 3）可得按實(shí)際載荷系數(shù)算的的分度圓直徑d3 = = = mm及相應(yīng)的齒輪模數(shù)mn = d3/z3 = 模數(shù)取為標(biāo)準(zhǔn)值m = 4 mm。（1）齒根彎曲疲勞強(qiáng)度條件sF = ≤ [σF]1）確定公式中各參數(shù)值①計(jì)算彎曲疲勞強(qiáng)度用重合度系數(shù)YeYe = ++②由齒數(shù)，查圖得齒形系數(shù)和應(yīng)力修正系數(shù)YFa1 = YFa2 = YSa1 = YSa2 = ③計(jì)算實(shí)際載荷系數(shù)KF由表查得齒間載荷分配系數(shù)aKFa = 根據(jù)KHb = ，結(jié)合b/h = = = 則載荷系數(shù)為KF = KAKvKFaKFb= 1 = ④計(jì)算齒根彎曲疲勞許用應(yīng)力[σF]查得小齒輪和大齒輪的彎曲疲勞極限分別為sFlim1 = 620 MPa、sFlim2 = 620 MPa。 齒數(shù)z1 = 2z2 = 67，模數(shù)m = 4 mm，壓力角a = 20176。代號(hào)名稱計(jì)算公式低速級(jí)小齒輪低速級(jí)大齒輪模數(shù)m4mm4mm齒數(shù)z2367齒寬b97mm92mm分度圓直徑d92mm268mm齒頂高系數(shù)ha頂隙系數(shù)c齒頂高h(yuǎn)amha4mm4mm齒根高h(yuǎn)fm(ha+c)5mm5mm全齒高h(yuǎn)ha+hf9mm9mm齒頂圓直徑dad+2ha100mm276mm齒根圓直徑dfd2hf82mm258mm 輸入軸的設(shè)計(jì)、轉(zhuǎn)速n1和轉(zhuǎn)矩T1P1 = KW n1 = 480r/min T1 = 已知高速級(jí)小齒輪的分度圓直徑為:d1 = 66 mm 則:Ft = = = NFr = Fttana = tan20176。選取軸的材料為45鋼，調(diào)質(zhì)處理，根據(jù)表，取A0 = 112，得：dmin = A0 = 112 = 輸入軸的最小直徑是安裝大帶輪處的軸徑，由于安裝鍵將軸徑增大5%，故選取:d12 = 26mm 1）為了滿足大帶輪的軸向定位要求，III軸段右端需制出一軸肩，故取II=III段的直徑d23 = 30 mm；左端用軸端擋圈定位，按軸端直徑取擋圈直徑D = 35 mm。 2）初步選擇滾動(dòng)軸承。參照工作要求并根據(jù)d23 = 30 mm，由軸承產(chǎn)品目錄中選擇深溝球軸承6207，其尺寸為dDT = 357217 mm，故d34 = d78 = 35 mm，取擋油環(huán)的寬度為15，則l34 = l78 = 17+15 = 32 mm。由手冊(cè)上查得6207型軸承的定位軸肩高度h = mm，因此，取d45 = d67 = 42 mm。所以l56 = B = 71 mm，d56 = d1 = 66 mm 4）根據(jù)軸承端蓋便于裝拆，保證軸承端蓋的外端面與大帶輪右端面有一定距離，取l23 = 50 mm?？紤]箱體的鑄造誤差，在確定滾動(dòng)軸承位置時(shí)，應(yīng)距箱體內(nèi)壁一段距離s，取s = 8 mm，已知低速小齒輪的寬度b3 = 97 mm，則l45 = b3+c+Δ+s15 = 97+12+16+815 = 118 mml67 = Δ+s15 = 9 mm至此，已初步確定了軸的各段直徑和長(zhǎng)度。截面C處的合成彎矩：M1 = = 313819 NmmM2 = = 154253 Nmm作合成彎矩圖（圖f）。5）按彎扭組合強(qiáng)度條件校核軸的強(qiáng)度： 通常只校核軸上承受最大彎矩和轉(zhuǎn)矩的截面（即危險(xiǎn)截面C）的強(qiáng)度。根據(jù)公式（144），取a = ，
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