帶式輸送器傳動裝置三維建模和運(yùn)動模擬【說明書+SOLIDWORKS】,說明書+SOLIDWORKS,帶式輸送器傳動裝置三維建模和運(yùn)動模擬【說明書+SOLIDWORKS】,輸送,傳動,裝置,三維,建模,以及,運(yùn)動,模擬,摹擬,說明書,仿單,solidworks 第 - 27 -頁 目 錄 設(shè)計任務(wù)書…………………………………………………2 第一部分 傳動裝置總體設(shè)計……………………………4 第二部分 V帶設(shè)計………………………………………6 第三部分 各齒輪的設(shè)計計算……………………………9 第四部分 軸的設(shè)計………………………………………13 第五部分 校核……………………………………………19 第六部分 主要尺寸及數(shù)據(jù)………………………………21 設(shè) 計 任 務(wù) 書 一、 課程設(shè)計題目： 設(shè)計帶式運(yùn)輸機(jī)傳動裝置（簡圖如下） F V 1 2 3 4 5 6 1—電動機(jī)；2—帶傳動；3—兩級圓柱齒輪減速器； 4—聯(lián)軸器；5—滾筒；6—輸送帶 工作條件： 連續(xù)單向運(yùn)轉(zhuǎn)，工作時有輕微振動，使用期限為10年，小批量生產(chǎn)，單班制工作（8小時/天）。運(yùn)輸速度允許誤差為。 二、 課程設(shè)計內(nèi)容 1）傳動裝置的總體設(shè)計。 2）傳動件及支承的設(shè)計計算。 3）減速器裝配圖及零件工作圖。 4）設(shè)計計算說明書編寫。 每個學(xué)生應(yīng)完成： 1） 部件裝配圖一張（A1）。 2） 零件工作圖兩張（A3） 3） 設(shè)計說明書一份（6000~8000字）。 本組設(shè)計數(shù)據(jù)： 第三組數(shù)據(jù)：運(yùn)輸機(jī)工作軸轉(zhuǎn)矩T/(N.m) 5900 。 運(yùn)輸機(jī)帶速V/(m/s) 0.45 。 卷筒直徑D/mm 335 。 已給方案：外傳動機(jī)構(gòu)為V帶傳動。 減速器為兩級圓柱齒輪減速器。 第一部分 傳動裝置總體設(shè)計 一、 傳動方案（已給定） 1） 外傳動為V帶傳動。 2） 減速器為兩級展開式圓柱齒輪減速器。 3） 方案簡圖如下： F V 1 2 3 4 5 6 二、該方案的優(yōu)缺點： 該工作機(jī)有輕微振動，由于V帶有緩沖吸振能力，采用V帶傳動能減小振動帶來的影響，并且該工作機(jī)屬于小功率、載荷變化不大，可以采用V帶這種簡單的結(jié)構(gòu)，并且價格便宜，標(biāo)準(zhǔn)化程度高，大幅降低了成本。減速器部分兩級展開式圓柱齒輪減速，這是兩級減速器中應(yīng)用最廣泛的一種。齒輪相對于軸承不對稱，要求軸具有較大的剛度。高速級齒輪常布置在遠(yuǎn)離扭矩輸入端的一邊，以減小因彎曲變形所引起的載荷沿齒寬分布不均現(xiàn)象。原動機(jī)部分為Y系列三相交流異步電動機(jī)。 總體來講，該傳動方案滿足工作機(jī)的性能要求，適應(yīng)工作條件、工作可靠，此外還結(jié)構(gòu)簡單、尺寸緊湊、成本低傳動效率高。 計 算 與 說 明 三、原動機(jī)選擇（Y系列三相交流異步電動機(jī)） 工作機(jī)所需功率： Pw = Fv/1000 =5900 * 0.45/1000 =2.655kw (見課設(shè)P9) 傳動裝置總效率：（見課設(shè)式2-4） （見課設(shè)表12-8） 電動機(jī)的輸出功率： （見課設(shè)式2-1） 取 選擇電動機(jī)為Y132M1-6型 （見課設(shè)表19-1） 技術(shù)數(shù)據(jù)：額定功率（） 4 滿載轉(zhuǎn)矩（） 960 額定轉(zhuǎn)矩（） 2.0 最大轉(zhuǎn)矩（） 2.0 Y132M1-6電動機(jī)的外型尺寸（mm）： （見課設(shè)表19-3） A：216 B：178 C：89 D：38 E：80 F：10 G：33 H：132 K：12 AB：280 AC：270 AD：210 HD：315 BB：238 L：235 四、傳動裝置總體傳動比的確定及各級傳動比的分配 1、 總傳動比： （見課設(shè)式2-6） n==60x1000x0.45/3.14x335＝25.67r/min 2、 各級傳動比分配： （見課設(shè)式2-7） 初定 第二部分 V帶設(shè)計 外傳動帶選為 普通V帶傳動 1、 確定計算功率： 1）、由表5-9查得工作情況系數(shù) 2）、由式5-23（機(jī)設(shè)） 2、選擇V帶型號 查圖5-12a(機(jī)設(shè))選A型V帶。 3.確定帶輪直徑 （1）、參考圖5-12a（機(jī)設(shè)）及表5-3（機(jī)設(shè)）選取小帶輪直徑 （電機(jī)中心高符合要求） （2）、驗算帶速 由式5-7（機(jī)設(shè)） （3）、從動帶輪直徑 查表5-4（機(jī)設(shè)） 取 （4）、傳動比 i 4.確定中心距和帶長 （1）、按式（5-23機(jī)設(shè)）初選中心距 取 （2）、按式(5-24機(jī)設(shè))求帶的計算基礎(chǔ)準(zhǔn)長度L0 　　　　　　 查圖.5-7(機(jī)設(shè))取帶的基準(zhǔn)長度Ld=2000mm (3)、按式(5-25機(jī)設(shè))計算中心距:a (4)、按式（5-26機(jī)設(shè)）確定中心距調(diào)整范圍 5.驗算小帶輪包角α1 由式(5-11機(jī)設(shè)) 6.確定V帶根數(shù)Z (1)、由表（5-7機(jī)設(shè)）查得dd1=112 n1=800r/min及n1=980r/min時，單根V帶的額定功率分呷為1.00Kw和1.18Kw，用線性插值法求n1=980r/min時的額定功率P0值。 (2)、由表（5-10機(jī)設(shè)）查得△P0=0.11Kw (3)、由表查得（5-12機(jī)設(shè)）查得包角系數(shù) (4)、由表(5-13機(jī)設(shè))查得長度系數(shù)KL=1.03 (5)、計算V帶根數(shù)Z，由式（5-28機(jī)設(shè)） 取Z=5根 7．計算單根V帶初拉力F0，由式（5-29）機(jī)設(shè)。 q由表5-5機(jī)設(shè)查得 8．計算對軸的壓力FQ，由式（5-30機(jī)設(shè)）得 9．確定帶輪的結(jié)構(gòu)尺寸，給制帶輪工作圖 小帶輪基準(zhǔn)直徑dd1=112mm采用實心式結(jié)構(gòu)。大帶輪基準(zhǔn)直徑dd2=280mm，采用孔板式結(jié)構(gòu)，基準(zhǔn)圖見零件工作圖。 第三部分 各齒輪的設(shè)計計算 一、高速級減速齒輪設(shè)計（直齒圓柱齒輪） 1.齒輪的材料，精度和齒數(shù)選擇，因傳遞功率不大，轉(zhuǎn)速不高，材料按表7-1選取，都采用45號鋼，鍛選項毛坯，大齒輪、正火處理，小齒輪調(diào)質(zhì)，均用軟齒面。齒輪精度用8級，輪齒表面精糙度為Ra1.6，軟齒面閉式傳動，失效形式為占蝕，考慮傳動平穩(wěn)性，齒數(shù)宜取多些，取Z1=34 則Z2=Z1i=34×2.62=89 2.設(shè)計計算。 （1）設(shè)計準(zhǔn)則，按齒面接觸疲勞強(qiáng)度計算，再按齒根彎曲疲勞強(qiáng)度校核。 （2）按齒面接觸疲勞強(qiáng)度設(shè)計，由式（7-9） T1=9.55×106×P/n=9.55×106×5.42/384=134794 N·mm 選取材料的接觸疲勞，極限應(yīng)力為 бHILim=580 бHILin=560 選取材料彎曲疲勞極陰應(yīng)力 бHILim=230 бHILin=210 應(yīng)力循環(huán)次數(shù)N由式（7-3）計算 N1=60n, at=60×(8×360×10)=6.64×109 N2= N1/u=6.64×109/2.62=2.53×109 由圖7-8查得接觸疲勞壽命系數(shù)；ZN1=1.1 ZN2=1.04 由圖7-9查得彎曲 ；YN1=1 YN2=1 由圖7-2查得接觸疲勞安全系數(shù)：SFmin=1.4 又YST=2.0 試選Kt=1.3 由式(7-1)(7-2)求許用接觸應(yīng)力和許用彎曲應(yīng)力 將有關(guān)值代入式(7-9)得 則V1=(πd1tn1/60×1000)=1.3m/s ( Z1 V1/100)=1.3×(34/100)m/s=0.44m/s 查圖7-10得Kv=1.05 由表7-3查和得K A=1.25.由表7-4查得Kβ=1.08.取Kα=1.05.則KH=KAKVKβKα=1.42 ,修正 M=d1/Z1=1.96mm 由表7-6取標(biāo)準(zhǔn)模數(shù)：m=2mm (3) 計算幾何尺寸 d1=mz1=2×34=68mm d2=mz2=2×89=178mm a=m(z1＋z2)/2=123mm b=φddt=1×68=68mm 取b2=65mm b1=b2+10=75 3.校核齒根彎曲疲勞強(qiáng)度 由圖7-18查得，YFS1=4.1，YFS2=4.0 取Yε=0.7 由式(7-12)校核大小齒輪的彎曲強(qiáng)度. 二、低速級減速齒輪設(shè)計（直齒圓柱齒輪） 1.齒輪的材料，精度和齒數(shù)選擇，因傳遞功率不大，轉(zhuǎn)速不高，材料按表7-1選取，都采用45號鋼，鍛選項毛坯，大齒輪、正火處理，小齒輪調(diào)質(zhì)，均用軟齒面。齒輪精度用8級，輪齒表面精糙度為Ra1.6，軟齒面閉式傳動，失效形式為占蝕，考慮傳動平穩(wěn)性，齒數(shù)宜取多些，取Z1=34 則Z2=Z1i=34×3.7=104 2.設(shè)計計算。 （1） 設(shè)計準(zhǔn)則，按齒面接觸疲勞強(qiáng)度計算，再按齒根彎曲疲勞強(qiáng)度校核。 （2）按齒面接觸疲勞強(qiáng)度設(shè)計，由式（7-9） T1=9.55×106×P/n=9.55×106×5.20/148=335540 N·mm 由圖（7-6）選取材料的接觸疲勞，極限應(yīng)力為 бHILim=580 бHILin=560 由圖 7-7選取材料彎曲疲勞極陰應(yīng)力 бHILim=230 бHILin=210 應(yīng)力循環(huán)次數(shù)N由式（7-3）計算 N1=60n at=60×148×(8×360×10)=2.55×109 N2= N1/u=2.55×109/3.07=8.33×108 由圖7-8查得接觸疲勞壽命系數(shù)；ZN1=1.1 ZN2=1.04 由圖7-9查得彎曲 ；YN1=1 YN2=1 由圖7-2查得接觸疲勞安全系數(shù)：SFmin=1.4 又YST=2.0 試選Kt=1.3 由式(7-1)(7-2)求許用接觸應(yīng)力和許用彎曲應(yīng)力 將有關(guān)值代入式(7-9)得 則V1=(πd1tn1/60×1000)=0.55m/s ( Z1 V1/100)=0.55×(34/100)m/s=0.19m/s 查圖7-10得Kv=1.05 由表7-3查和得K A=1.25.由表7-4查得Kβ=1.08.取Kα=1.05.則KH=KAKVKβKα=1.377 ,修正 M=d1/Z1=2.11mm 由表7-6取標(biāo)準(zhǔn)模數(shù)：m=2.5mm (3) 計算幾何尺寸 d1=mz1=2.5×34=85mm d2=mz2=2.5×104=260mm a=m(z1＋z2)/2=172.5mm b=φddt=1×85=85mm 取b2=85mm b1=b2+10=95 3.校核齒根彎曲疲勞強(qiáng)度 由圖7-18查得，YFS1=4.1，YFS2=4.0 取Yε=0.7 由式(7-12)校核大小齒輪的彎曲強(qiáng)度. 總結(jié)：高速級 z1=34 z2=89 m=2 低速級 z1=34 z2=104 m=2.5 第四部分 軸的設(shè)計 (一).軸的設(shè)計 Ⅰ.輸出軸上的功率、轉(zhuǎn)速和轉(zhuǎn)矩 由上可知，， Ⅱ.初步確定軸的最小直徑 材料為45鋼，正火處理。根據(jù)《機(jī)械設(shè)計》表11.3，取，于是 ， 由于鍵槽影響，故 輸出軸的最小直徑顯然是安裝聯(lián)軸器處軸的直徑。為了使所選的軸直徑與聯(lián)軸器的孔徑相適應(yīng)，故需同時選取聯(lián)軸器型號。 聯(lián)軸器的計算轉(zhuǎn)矩，查《機(jī)械設(shè)計》表10.1，取，則： 按照計算轉(zhuǎn)矩應(yīng)小于聯(lián)軸器公稱轉(zhuǎn)矩的條件，查《機(jī)械設(shè)計——課程設(shè)計手冊》P188頁，選用GY5型聯(lián)軸器，其公稱轉(zhuǎn)矩為 。半聯(lián)軸器的孔徑 ，故取，半聯(lián)軸器與軸配合的轂孔長度 圖4-1 軸 III.軸的結(jié)構(gòu)設(shè)計 (1).根據(jù)軸向定位的要求確定軸的各段直徑和長度 1).為了滿足半聯(lián)軸器的軸向定位要求，1-2段右端需制出一軸肩，故取2-3段的直徑；左端用軸端擋圈定位。半聯(lián)軸器與軸配合的轂孔長度，為了保證軸端擋圈只壓在半聯(lián)軸器上而不壓在軸的端面上，故1-2段的長度應(yīng)比略短一些，現(xiàn)取。 2).初步選擇滾動軸承。因軸承只受有徑向力的作用，故選用深溝球軸承。按照工作要求并根據(jù)，查《機(jī)械設(shè)計——課程設(shè)計手冊》P203頁表7.3.1選取深溝球軸承6208，其尺寸為，故。取, 3).取安裝齒輪處的軸端4-5的直徑。已知齒輪輪轂的跨度為48mm，為了使擋油環(huán)端面可靠地壓緊齒輪，此軸端應(yīng)略短于輪轂寬度，故取。齒輪的左端采用軸肩定位，軸肩高度，故取，則軸環(huán)處的直徑。軸環(huán)寬度，取。 4).軸承端蓋的總寬度為(由減速器及軸承端蓋的結(jié)構(gòu)設(shè)計而定)。根據(jù)軸承端蓋的裝拆及便于對軸承添加潤滑脂的要求，取端蓋的外端面與半聯(lián)軸器右端面間的距離，故。 5).取齒輪距箱體內(nèi)壁的距離，考慮到箱體的鑄造誤差，在確定滾動軸承位置時，應(yīng)距箱體內(nèi)壁一段距離，取，已知滾動軸承寬度，則 至此，已初步確定了軸的各段和長度。 (2).軸上零件的周向定位 齒輪、半聯(lián)軸器與軸的周向定位均采用平鍵連接。由《機(jī)械設(shè)計手冊》表6.2.2查得平鍵截面，鍵槽用鍵槽銑刀加工，長為，同時為了保證齒輪與軸配合有良好的對中性，故選擇齒輪輪轂與軸的配額為；同樣，半聯(lián)軸器與軸的連接，選用平鍵為，半聯(lián)軸器與軸的配合為。滾動軸承與軸的周向定位是由過度配合來保證的，此處選軸的直徑尺寸公差為。 (3).確定軸上圓角和倒角尺寸 參考《機(jī)械設(shè)計》表1-27，取軸端圓角。 Ⅴ.求軸上的載荷 首先根據(jù)軸的結(jié)構(gòu)圖做出軸的計算簡圖，作為簡支梁的軸的支撐跨距。根據(jù)軸的計算簡圖做出軸的彎矩圖和扭矩圖。 圖4-2 軸的彎矩和扭矩 其中， 這兩個數(shù)值在小齒輪設(shè)計時已獲得。 帶入已知量，得， 同理可得， 總彎矩 M= 扭矩 T= 從軸的結(jié)構(gòu)圖以及彎矩和扭矩圖中可以看出截面C是軸的危險截面?，F(xiàn)將計算處的截面C處的、及的值列于下表。 載荷 水平面H 垂直面V 支反力 彎矩 總彎矩 扭矩 Ⅵ.按彎扭合成應(yīng)力校核軸的強(qiáng)度 進(jìn)行校核時，通常只校核軸上承受最大彎矩和扭矩的截面（即危險截面C）的強(qiáng)度。根據(jù)上表數(shù)據(jù)，以及軸單向旋轉(zhuǎn)，扭轉(zhuǎn)切應(yīng)力為脈動循環(huán)變應(yīng)力，取，軸的計算應(yīng)力 其中，W為抗彎截面系數(shù)，對于齒輪軸 帶入數(shù)值可得， 前已選定軸的材料為45鋼，調(diào)質(zhì)處理，由《機(jī)械設(shè)計》表7-1查得 因此，故安全。 輸出軸采用相同的方法可以校核。 (二).齒輪軸的設(shè)計 Ⅰ.輸出軸上的功率、轉(zhuǎn)速和轉(zhuǎn)矩 由上可知，， Ⅱ.求作用在齒輪上的力 因已知小齒輪的分度圓直徑 而 Ⅲ.初步確定軸的最小直徑 材料為45鋼，正火處理。根據(jù)《機(jī)械設(shè)計》表11.3，取，于是，由于鍵槽的影響，故,輸出軸的最小直徑顯然是安裝聯(lián)軸器處軸的直徑。為了使所選的軸直徑與聯(lián)軸器的孔徑相適應(yīng)，故需同時選取聯(lián)軸器型號。 聯(lián)軸器的計算轉(zhuǎn)矩，查《機(jī)械設(shè)計》表10.1，取，則： 按照計算轉(zhuǎn)矩應(yīng)小于聯(lián)軸器公稱轉(zhuǎn)矩的條件，查《機(jī)械設(shè)計——課程設(shè)計手冊》P188頁，選用GY1型聯(lián)軸器，其公稱轉(zhuǎn)矩為。半聯(lián)軸器的孔徑 ，故取，半聯(lián)軸器與軸配合的轂孔長度 圖4-4 軸 Ⅳ.齒輪軸的結(jié)構(gòu)設(shè)計 (1).根據(jù)軸向定位的要求確定軸的各段直徑和長度 1). 為了滿足辦聯(lián)軸器的軸向定位要求，Ⅰ-Ⅱ段右端需制出一軸肩，故?、?Ⅲ段的直徑；左端用軸端擋圈定位。半聯(lián)軸器與軸配合的轂孔長度，為了保證軸端擋圈只壓在半聯(lián)軸器上而不壓在軸的端面上，故Ⅰ-Ⅱ段的長度應(yīng)比略短一些，現(xiàn)取。 2).初步選擇滾動軸承。因軸承只受徑向力的作用，故選用深溝球軸承。按照工作要求并根據(jù)，查機(jī)械設(shè)計手冊表6-1選取深溝球軸承6205，其尺寸為，故，暫取。 3).根據(jù)軸承的定位要求取， 。為了保證輸入軸和Ⅱ軸齒輪相對位置，參考輸出軸尺寸，暫取。 4).軸承端蓋的總寬度為(由減速器及軸承端蓋的結(jié)構(gòu)設(shè)計而定)。根據(jù)軸承端蓋的裝拆及便于對軸承添加潤滑脂的要求，取端蓋的外端面與半聯(lián)軸器右端面間的距離，故。 5).由小齒輪尺寸可知，齒輪處的直徑，。至此，已初步確定了軸的各段和長度。 (2).軸上零件的周向定位 半聯(lián)軸器與軸的周向定位均采用平鍵連接。按由《機(jī)械設(shè)計設(shè)計手冊》表4-1查得平鍵截面，鍵槽用鍵槽銑刀加工，長為。同時為了保證半聯(lián)軸器與軸配合有良好的對中性，故選擇半聯(lián)軸器與軸的配額為；滾動軸承與軸的周向定位是由過渡配合來保證的，此處選軸的直徑尺寸公差為。 (3).確定軸上圓角和倒角尺寸 參考《機(jī)械設(shè)計手冊》表1-27，取軸端圓角。 Ⅴ.求軸上的載荷 首先根據(jù)軸的結(jié)構(gòu)圖做出軸的計算簡圖。作為簡支梁的軸的支撐跨距。根據(jù)軸的計算簡圖做出軸的彎矩圖和扭矩圖。 其中， 這兩個數(shù)值在小齒輪設(shè)計時已獲得。 帶入已知量，得， 同理可得， 總彎矩 M= 扭矩 T= 從軸的結(jié)構(gòu)圖以及彎矩和扭矩圖中可以看出截面C是軸的危險截面?，F(xiàn)將計算處的截面C處的、及的值列于下表。 載荷 水平面H 垂直面V 支反力 彎矩 總彎矩 扭矩 Ⅵ.按彎扭合成應(yīng)力校核軸的強(qiáng)度 進(jìn)行校核時，通常只校核軸上承受最大彎矩和扭矩的截面（即危險截面C）的強(qiáng)度。根據(jù)上表數(shù)據(jù)，以及軸單向旋轉(zhuǎn)，扭轉(zhuǎn)切應(yīng)力為脈動循環(huán)變應(yīng)力，取，軸的計算應(yīng)力 其中，W為抗彎截面系數(shù)，對于齒輪軸 帶入數(shù)值可得， 前已選定軸的材料為45鋼，調(diào)質(zhì)處理，由《機(jī)械設(shè)計》表7-1查得 因此，故安全。 輸出軸采用相同的方法可以校核。 聯(lián)軸器的選擇 聯(lián)軸器選擇為TL8型彈性聯(lián)軸器 GB4323-84 減速器的潤滑 1.齒輪的潤滑 因齒輪的圓周速度<12 m/s，所以才用浸油潤滑的潤滑方式。 高速齒輪浸入油里約0.7個齒高，但不小于10mm，低速級齒輪浸入油高度約為1個齒高（不小于10mm），1/6齒輪。 2．滾動軸承的潤滑 因潤滑油中的傳動零件（齒輪）的圓周速度V≥1.5～2m/s所以采用飛濺潤滑， 第五部分 主要尺寸及數(shù)據(jù) 減速器的箱體采用鑄造（HT200）制成，采用剖分式結(jié)構(gòu)為了保證齒輪佳合質(zhì)量，大端蓋分機(jī)體采用配合。 （1） 機(jī)體有足夠的剛度 在機(jī)體為加肋，外輪廓為長方形，增強(qiáng)了軸承座剛度 2. 考慮到機(jī)體內(nèi)零件的潤滑，密封散熱。 因其傳動件速度小于12m/s，故采用侵油潤油，同時為了避免油攪得沉渣濺起，齒頂?shù)接统氐酌娴木嚯xH大于40mm;為保證機(jī)蓋與機(jī)座連接處密封，聯(lián)接凸緣應(yīng)有足夠的寬度，聯(lián)接表面應(yīng)精創(chuàng)，其表面粗糙度為6.3。 3. 機(jī)體結(jié)構(gòu)有良好的工藝性. 鑄件壁厚為12mm，圓角半徑為R=6。機(jī)體外型簡單，拔模方便. 4. 對附件設(shè)計 A 視孔蓋和窺視孔 在機(jī)蓋頂部開有窺視孔，能看到 傳動零件齒合區(qū)的位置，并有足夠的空間，以便于能伸入進(jìn)行操作，窺視孔有蓋板，機(jī)體上開窺視孔與凸緣一塊，有便于機(jī)械加工出支承蓋板的表面并用墊片加強(qiáng)密封，蓋板用鑄鐵制成，用M8緊固 B 油螺塞： 放油孔位于油池最底處，并安排在減速器不與其他部件靠近的一側(cè)，以便放油，放油孔用螺塞堵住，因此油孔處的機(jī)體外壁應(yīng)凸起一塊，由機(jī)械加工成螺塞頭部的支承面，并加封油圈加以密封。 C 油標(biāo)： 油標(biāo)位在便于觀察減速器油面及油面穩(wěn)定之處; 油尺安置的部位不能太低，以防油進(jìn)入油尺座孔而溢出. D 通氣孔： 由于減速器運(yùn)轉(zhuǎn)時，機(jī)體內(nèi)溫度升高，氣壓增大，為便于排氣，在機(jī)蓋頂部的窺視孔改上安裝通氣器，以便達(dá)到體內(nèi)為壓力平衡. E 位銷： 為保證剖分式機(jī)體的軸承座孔的加工及裝配精度，在機(jī)體聯(lián)結(jié)凸緣的長度方向各安裝一圓錐定位銷，以提高定位精度. F 吊鉤： 在機(jī)蓋上直接鑄出吊鉤和吊環(huán)，用以起吊或搬運(yùn)較重的物體. 減速器機(jī)體結(jié)構(gòu)尺寸如下： 表5-3 箱體參數(shù)統(tǒng)計表 名稱 符號 計算公式 結(jié)果 箱座壁厚 13 箱蓋壁厚 8 箱蓋凸緣厚度 14 箱座凸緣厚度 13 箱座底凸緣厚度 27 地腳螺釘直徑 M22 地腳螺釘數(shù)目 查手冊 6 軸承旁聯(lián)接螺栓直徑 M14 機(jī)蓋與機(jī)座聯(lián)接螺栓直徑 =（0.5~0.6） M10 軸承端蓋螺釘直徑 =（0.4~0.5） M8 視孔蓋螺釘直徑 =（0.3~0.4） M6 定位銷直徑 =（0.7~0.8） 6 ，，至外機(jī)壁距離 查《機(jī)械設(shè)計課程設(shè)計指導(dǎo)書》表11-2 26 24 22 ，至凸緣邊緣距離 查《機(jī)械設(shè)計課程設(shè)計指導(dǎo)書》表11-2 25 15 外機(jī)壁至軸承座端面距離 =++（8~12） 56 大齒輪頂圓與內(nèi)機(jī)壁距離 >1.2 18 齒輪端面與內(nèi)機(jī)壁距離 > 16 機(jī)座肋厚 、m1 .6 軸承端蓋外徑 +（5~5.5） 110 70 參考文獻(xiàn)： 《機(jī)械設(shè)計》徐錦康 主編 機(jī)械工業(yè)出版社 《機(jī)械設(shè)計課程設(shè)計》陸玉 何在洲 佟延偉 主編 第3版 機(jī)械工業(yè)出版社 《機(jī)械設(shè)計手冊》 - 27 - CHINESE JOURNAL OF MECHANICAL ENGINEER【NG Vo122，No5，2009 671 DOI：103901CJME200905671，available online at www cjmeneteom；wwwcjmenetcornca Design System of the Twostep Gear Reducer on Casebased Reasoning JI Aimin ， 一，HUANG Quansheng ，XU Huanmin ，and CHEN Zhengming。 1 College ofMechanical and Electrical Engineering,Hohai University,Changzhou 213022，China 2 StateKeyLab ofCAD&CG,Zhiang University,Hangzhou 310058,China 3 College ofComputer and Information Engineering,Hohai University,Changzhou 213022，China Received November 1 8，2008；revised May 22，2009；accepted August 10 ，2009；published electronically August 14，2009 Abstract：The design of the two-step gear reducer is a tedious and time-consuming process For the purpose of improving me efficiencv and intelligence of design process，casebased reasoning(CBR)technology was applied to the design of the twostep gear reducen Firstly, the current design method for the twostep gear reducer was analyzed and the princiFlle of CBR was described Secondly,according to the characteristics of the reducer,three key technologies of CBR were studied and the corresponding methods were provided ，which are as follows：(a)an objectoriented knowledge representation method,(b)a retrieval method combining the nearest neighbor with the induction indexing，and(c)a case adaptation algorithm combining the revision based on rule with artificial revisionAlsofor the purpose of improving the credibility of case retrieval，a new method for determining the weights of characteristics and a similarity formula were presented，which is a combinatorial weighting method with the analytic hierarchy process(AHP)and roughness set theory Lastly,according to the above analytic results，a design system of the two-step gear reducer on CBR was developed by VC+ UG and Access 2003A new method for the design of the twostep gear reducer is provided in this studyIf the foregoing developed system is applied to design the two-step gear reduceg design efficiency is improved，which enables the designer to release from the tedious design process of the gear reducer so as to put more efforts on innovative designThe study result fully reflects the feasibility and validity of CBR technology in the process of the design of the mechanical parts Key words：twostep gear reducecasebased reasoning(CBR)，weights of characteristics，similarity 1 Introduction The traditional design method of the twostep gear reducer is a timeconsuming processEven now CAD is used in its design processrestriction of the traditional design method is not eliminated up to nowFor the sake of changing this kind of situation，many people have done research on the design method of reducer，mainly including the parametric design of reducer and expert system(ES)These two kinds of memods have respective shortcomings：for parametric design，every parts relation need to be fully considered，because a parameters change carl cause a change of a reducers other parameters or structure，which requires designer to acquaint with a reducer and be able to use a design software including the function of the parametric designFurthermore knowledge acquirement is very difficult in reducers ESbecause some expert knowledge js very difficult to express with rules Casebased reasoning(CBR、can improve these two kinds Corresponding authorEmail：iamustcedu This project is supported by National Hitech Research and Development Program of China(863 Program， Grant No 2008AA04Z115)，Science and Technology Program of the Ministry of Construction of China(Grant No2008一K821，Jiangsu ProvinciaI NatI1ra1 Science Foundation of China(Grant NoBK2007042)，and Open Fund of State Key Lab of CAD&CGZhejiang University,China(Grant No A0914、 of shortcomingsA new case is finished on the base of an existed case in CBRso the new case can be achieved by modilying some parts or directly making use of the existed case，and case acquirement is easier than rule acquirement， because the primary knowledge js cases in CBRL JIn f-act case usually provides more information than rule or model_jJ_Many researchers have done a lot of work for applications Of CBR in engineering SUN et alL斗J developed an intelligent fixture design system on CBR KW0NGet al_)Jintroduced a approach to determine proper injection moulding parameters by developed CBR systemLIUet al proposed a retrieval algorithm integrated with the clustering technique to locate the similar cases in the casebase and gave a casebase to illustrate the feasibility of the CBR system in the mechanical design PETERL developed an automated knowledgebased system on CBR for intelligent support of the preprocessing stage of engineering analysis in the contact mechanics domainX10NGet al provided an applied and creative conceptua1 design method based on CBR that embodies the indus仃ial design knowledgeThe system developed abbreviates the conceptual design process，help designers， and provides a base for the following development of productHowever the works described above paid attention to the theoretical research on CBR superior to the combination of CBR technology with mechanical product 672 JI Aimin，et al：Design System ofthe Twostep Gear Reducer on C ase -ba sed Rea soning So，taken the twostep gear reducer as example，the whole process of mechanical parts on CBR will be discussed 2 Key Technologies in CBR The CBR is a kind of similar or analogical methOd When a CBR system solves a new problem，it retrieves one or more cases from the antecedent cases that are the most similar to the new problem，and modifies the cases to sarisfy the new situation The flowchart of the CBR is shown in Fig1According to the flowchart of the CBR， the development of the product design system on CBR needs to solve some problem，including case description， case retrieval，case modification，case study and case base maintenance where case description，case retrieval and case modification are called three key technologies Fig1Flowchart of CBR Case description is the action that cases are coded to data structure accepted by computer with some conventional signsCase can be described by some methods including flame，object，predicate，semantic network and rules，etc， among which，frame and object are most commonly used Case retrieval is a process finding out one interrelated case or more similar cases by characteristic index and similarity JRef91 divides case retrievalinto three parts： characteristic identificationpreliminary matchand best selectionThe paper divides case retrieval into four parts： key characteristics extraction，characteristic identification preliminary match，and best selectionDataset of data mining often includes many characteristic attributesand some attributes are irrelevant to data miningThose irrelevant attributes influence efficiency of data mining Removing those irrelevant attributes can improve efficiency of data mining and make the result of data mining easier to understandThe purpose of key characteristics extraction is to select key characteristics to establish valid index from the case baseThe Durpose of characteristic identification is to select keY characteristics of new caseCharacteristic identificatiOn can be often made reference to key characteristic extractionBecause it includes a plentiful characteristic attributesthe key characteristic extraction of the twostep gear reducer is more importantThese typical methods of case retrieval include nearest neighbor， induction indexing， knowledgeguided，neural indexing on knowledge and template retrievalit0J Case modification is the process modifying the best- match case to meet the new design requirements，andthe most used methods include artificial modification， knowledgeintensive modification and knowledge-lacking modificationIt】 3 Design of the Twostep Gear Reducer on CBR 31 Case base building 3i1 Case&scription The paper USeS a case representation model of object- oriented layer 一 which provides an uniform object oriented data model to the upper so,ware，namely， provides all kinds of objectoriented concept，data structure， maintenance operation and flexible expansion，and provides a relation model of shielding concrete database to bottom，and establishes a transparent object conversion mechanism by mapping principle and carries on reasonable and valid managementMapping principle of object model is a relation of the conversion between a upper obiect oriented data model and a bottom relation model of databaseThe relation among object model layer，database， and other fimction module is shown in Fig2 user lnterface l Knowledge study and Knowledge reasoning and I mle ma ng mcFdu1e explaining module - 。 Description ofobjectoriented concept and its Object，oriented valid maintenance and flexible expansion model Controlling visiting and operation to underlying database by mapping principle J f Underlying 廠) database Fig2Objectoriented module representation The twostep gear reducer is a complicated assemblyfor the sake of convenience of case representation，the twostep gear reducer is divided into five component classes and two part classesThe five component classes are made of high speed gear group，low speed gear group，high speed shaft and bearing，middle shaft and bearing and low speed shaft and bearing，and the two part classes are made of the cover and the housingThese component classes can be broken up part classesFinally，every part class is mapped to its table in the underlying relation databaseTherefore，the objectoriented knowledge model on the twostep gear reducer is given in Fig3 CHINESE JOURNAL OF MECHANICAL ENGINEERING 673 oujectm。ddlayer f Thetw。一step gear reducer I l f + + + l High speed I 1 Low speed 曲speed shaft Middle shaft Low speed sham f geargroup f f geargroup and bearhag andbearhag andbearing 1 ! !J V ! ! + + 、 J s嘞edi Bearing shaft 薯 攀： ： Low ：R摹： ： l l L 二 p =卜； ：；， - t V I lTable gear1l Table gear2l Tablehigh shaft l Tablemidshaft l Tablebear2 lTabkbear3ITablexzuof Tablexgaif under1v_m9 rda nn dtahA P f Table bear2 Table CBRf l Tablelow shaft f Fig3Objectoriented knowledge model on the twostep gear reducer 312 Casebasebuilding According to the case representation model of the twostep gear reducer in Fig3，characteristic attribute values of the twostep gear reducers and their components are mapped to the underlying database，thus the case base is builtIn the underlying databaseeach table includes a “case numberfieldThe relation is established by“case numberbetween the tables mapped by every part and by the reducerFig4 shows the storage mode of case base of the twostep gear reducers in the database software of AccessDue to the limited spacethe paper doesnt list successively the partsstorage mode in Access Fig4Storage mode of the twostep gear reducers case base in the database software ofAccess 32 Case retrieval The Paper applies a retrieval method Of the combination of the nearest neighbor and the induction indexing，because the design of the two-step gear reducer is an experience process with a long history,twostep gear reducer includes many casesSoit is better to use the induction indexing to have a rOBgh retrieval。and use the nearest neighbor to have a fine retrieva1Fig5 shows me detailed retrieval process Fig5Flowchart of case retrieval process Now the paper describes the child process and method to case retrieval of the design system of the two-step gear reduceronCBRinturn 321 Kevcharacteristicextraction The characteristics of original case base are pre- processed before the key characteristic extraction (1)Preprocessing of dataThe discrete normalization processing of the quantitative parameters are transformed into the qualitative parameters by equal-frequency- intervals The principle of equalfrequency-intervals is to divide original interval into N small intervals(N is a discrete number given by user)，while each small interval has the almost same number of dataThe first and last intervals are expanded in the paper：the upper limit of the first interval is changed to zero，and the lower limit of the last interval changed to infinity，which ensures that a attribute value of a new case has a corresponding small interval with itbecause CBR is a process of uninterrupted study(the amount of case will uninterruptedly increase1， and avoid that small interval is divided again whenever a new case is added and retrieval of new case is not made beyond the attribute value of original case baseN intervals are identified with 0，1，2，n-1The qualitative characteristic attributes are assigned to0，1 1 by an increasing or decreasing orderFor example，precision grade of reducerhas three options for user to select in the 一 磊 一一一一一一 一一 一 一。一。一 一。一 一。一一 等 螢 一一 674 JI Aimin，et al：Design System ofthe Twostep Gear Reducer on Casebased Reasoning original case base：the class of 7the class of 8 and the class of 9The classes of 7，8，9 are expressed with 1，05，0， respectively according to the above-mentioned method The attribute value of the Boolean attribute is easy to ascertaim the same is 1the other is 0 f21 Key characteristic selectionThese clearly irrelevant characteristies are not directly considered in the data miningHowever many characteristics are difficult to identify their significance in the data miningThese characteristics are selected by the valid strategyThe paper uses decision仃ee to select key characteristics by the size of information gainDecision index tree is established by key characteristiesThe algorithm on the information gain of decision attributes may be referred to Ref1 2 The key characteristic selection on the twostep gear reducer is shown aS followsThe original case base is given inTable 1 Table 1Original case base Firstly，the clearly irrelevant characteristics to data mining are directly eliminatedThe other characteristics by the discrete normalization processing are changed into qualitative attributes， and then selected by the abovementioned algorithm of information gainSecondly the attribute of transmission power is divided into three smal1 intervals according to the abovementioned equalfrequencyintervals：(0，1 0)，1 0，20and(2o，o。) The qualitative numerical ranges are represented respectively with 0，1，2The attribute of transmission ratio 1ifespan and transmission efficiency are respectively divided into several corresponding small intervals (transmission ratio：(0，15)and(15，。)；lifespan：(0，350 ooo)，(350 000，420 ooo)and(420 000，。)：transmission efficiency：(0，094)and(094，1)Each interval numerical range is represented with 0，1， in turnThe attribute of the layout of gear drives is divided into two typesThe developed configuration is represented with 0，and the reverted configuration is represented with 1The result of discrete processing is obtained in Table 2 Table 2Result of discrete processing The at仃ibute of arrangement forrn is viewed as identification attributeand the other attributes are viewed as decision at仃ibuteThe case base is divided into two classes f =21 according to identification attributeThe first class is comprised of six cases whose arrangement forrn is expanding form(rl=6)，and the second arrangement is comprised of other cases whose arrangement form is coaxial form(r2 4、According to the algorithm of information gain，it is easy to acquire the information gains of all attributes as follows：GP：029，6 012，G，=029， G 001；where，Gpis the gain oftransmission power，Gi is the gain of transmission ratio，GL b is the gain of lifespan， G”iS the gain of transmission emciencyThus the attribute of transmission powertransmission ratio and lifespan can be selected as key characteristics from the value of all characteristic attributes 322 Preliminary match The preliminary match is the process that a group of cases interrelated to the current design case are selected from the case baseThe process is realized by index tree built by al1 key characteristics and decision information gain calculationThe index tree is built up as shown in Fig6The preliminary match of case is fulfilled based on theindextree 0 Fig6Index tree of key characteristics 3 23 Best selection The best selection is the process which the best case is selected from the cases acquired by the preliminary match CHINESE JOURNAL 0F MECHANICAL ENGINEER【NG 675 The best case is selected by the nearest neighbor，so it is indispensable for calculating the weight of the kev characteristics and cases similarity f 1、Weight of characteristic The weight of characteristic is used to evaluate significance of characteristicIt can influence the accuracy of reasoning resultAccording to the source of original informationthe method of determining the weight of characteristic is divided into two classes：the subjective method and the objective methodThe information of the subjective method comes from experts，and the information of the oNective is from statistical original dataThe representative approaches of the twoclass method are the analytic hierarchy process(AHP) and roughness set theoryt12J AHP is a kind of decision method that the decision problem is divided into some hierarchies including target，rule，project，etc，and qualitative analysis and quantitative analysis are conductedLet af，be importance degree of the characteristic f compared with the characteristic jThe weight(Dli of characteristic f acquired bv AHP can be calculated by the following formula： 1 i=1，2，z (1) Roughness set theory is a kind of data reasoning method in view of knowledge classification，which mainly applies to analysis of the dependence between reduction of knowledge and characteristic attribute，and solves the problem about the weight of characteristic attribute of similarity measureIt iudges the importance of all characteristic by existent information according to specific classifyingRelevant formulas of the weight calculation are given as foUows： ，D)= fW i曲t ofthe characteristic i acquired by roughness set theory The paper applies a method of combination of AHP and roughness set theory in order to compensate the defect of the two methodsThe combined method is assembled according to the linear superposition principle，The material combined forin is shown in Eq(5)： q=ao)1 +(1一 ) 2f， (5) where fWeight ofcharacteristic acquired by AHP， fweight of characteristic acquired by roughness set theory， Coefficient According to the combined method，the three weights of key characteristics of the reducer is respectively obtained， such as the attribute of transmission power，co1=052；the attribute of transmission ratio，co2=028；the attribute of ljfe-span，w3=O20(suppose a=05) f2、Similarity The characteristic values of the twostep gear reducer are comprised of quantitative parameters and qualitative parametersThe paper uses Eqs(6)and(7)to calculate the similari16J of quantitative characteristic， and the similarity of qualitative and Boolean characteristic have two conditions：0(different)or 1(same)So the paper presents a new algorithm of case similarity，which is expressed as follows Relative distance： , ；。 hv, -vok1 ； Characteristics similarit-y： (6) =1-d(Vf一 )=1-d ； (7) (2) Similarity between two cases SGF(a，C，D)=r(C，J)一r(C一 ，D)， (3) SGF(C一f)，D) 羔SGF(C一i)，D) ( 一， ) I=l i=1，2， ， (4) where r(c，D)-Dependence degree between attribute set C andD， fPOS(G f mber of elements in the union set， I Number ofthe object set， SGF(a，c，D)-Importance ofattribute a attribute setD， a SGF(C-i，D)-Importance degree ofthe characteristic i， k coiSDn sim(n，k)=旦 一 i=1 (8) Where Re1atiVe distance of the ith attribute of case ,and case屯 f-Characteristic value of the ith attribute of case ， -Characteristic value of the ith attribute of casek， -Similarity of the ith attribute of case and case k， sim(nk)-Similarity between the case，z and the case l一” 、 可 口 兀 ，。 676 JI Aimin，et al：Design System ofthe Twostep Gear Reducer Oil Casebased Reasoning 劬一Weight of the ith characteristic， ，2_Number of the characteristic Suppose to design the two-step gear reducer whose design conditions are shown in Table 3，and retrieve two cases which are obtained in Table 4 Table 3Design conditions Table 4Two retrieyed cases The weights of