不銹鋼瓦(wa)楞形(xing)板(ban)是不銹鋼寬幅型(xing)鋼的一(yi)種，由(you)于其(qi)形(xing)狀如同頂上用瓦(wa)片鋪(pu)成的行列隆起部分(fen)，故稱(cheng)為(wei)在線亞洲日產一區二區:不銹鋼瓦楞(leng)形板(ban)，如圖5-37所(suo)示。

 人們過去(qu)常見的(de)(de)“瓦楞(leng)（形(xing)）板”大(da)都(dou)是用(yong)普通低碳鋼，也就是非(fei)合金(jin)(jin)鋼材(cai)料制成的(de)(de)（見圖5-38),還有用(yong)非(fei)金(jin)(jin)屬材(cai)料如(ru)石(shi)棉、塑料、紙板等制成的(de)(de)瓦楞(leng)形(xing)板。這些瓦楞(leng)形(xing)板主(zhu)要(yao)用(yong)于建筑領(ling)域的(de)(de)屋頂材(cai)料、外墻材(cai)料和(he)(he)各種包裝箱體的(de)(de)外形(xing)材(cai)料和(he)(he)產品包裝箱、盒等，之所以做成瓦楞(leng)形(xing)狀，主(zhu)要(yao)目的(de)(de)是增加(jia)結(jie)構剛(gang)度和(he)(he)穩(wen)定(ding)性。因此，其尺寸(cun)精(jing)度和(he)(he)表面質量要(yao)求及材(cai)質要(yao)求都(dou)不是很高。

 此處介紹(shao)的(de)(de)(de)(de)不銹(xiu)(xiu)鋼瓦(wa)(wa)(wa)(wa)楞(leng)(leng)形(xing)(xing)板(ban)(ban)與普(pu)通(tong)的(de)(de)(de)(de)“瓦(wa)(wa)(wa)(wa)楞(leng)(leng)（形(xing)(xing)）板(ban)(ban)”有著本質(zhi)(zhi)的(de)(de)(de)(de)不同，首先材料(liao)是不銹(xiu)(xiu)鋼，無疑要(yao)(yao)比(bi)普(pu)通(tong)的(de)(de)(de)(de)“瓦(wa)(wa)(wa)(wa)楞(leng)(leng)（形(xing)(xing)）板(ban)(ban)”具有更高的(de)(de)(de)(de)強度(du)、良好的(de)(de)(de)(de)耐腐蝕性(xing)(xing)能和極好的(de)(de)(de)(de)裝飾效果，另外(wai)在結(jie)構上也大不相(xiang)同。這些(xie)都賦予了不銹(xiu)(xiu)鋼瓦(wa)(wa)(wa)(wa)楞(leng)(leng)形(xing)(xing)板(ban)(ban)不僅(jin)具有普(pu)通(tong)“瓦(wa)(wa)(wa)(wa)楞(leng)(leng)形(xing)(xing)板(ban)(ban)”的(de)(de)(de)(de)各(ge)種(zhong)功能與作(zuo)用，而且具有普(pu)通(tong)“瓦(wa)(wa)(wa)(wa)楞(leng)(leng)（形(xing)(xing)）板(ban)(ban)”沒有的(de)(de)(de)(de)功能，即不銹(xiu)(xiu)鋼瓦(wa)(wa)(wa)(wa)楞(leng)(leng)形(xing)(xing)板(ban)(ban)可以作(zuo)為(wei)(wei)傳熱(re)元件(jian)使用。作(zuo)為(wei)(wei)傳熱(re)元件(jian)，對(dui)其各(ge)方面的(de)(de)(de)(de)要(yao)(yao)求(qiu)(qiu)就比(bi)普(pu)通(tong)“瓦(wa)(wa)(wa)(wa)楞(leng)(leng)（形(xing)(xing)）板(ban)(ban)”高得多，特(te)別是對(dui)瓦(wa)(wa)(wa)(wa)楞(leng)(leng)形(xing)(xing)板(ban)(ban)表觀(guan)(guan)的(de)(de)(de)(de)要(yao)(yao)求(qiu)(qiu)。對(dui)瓦(wa)(wa)(wa)(wa)楞(leng)(leng)形(xing)(xing)板(ban)(ban)表觀(guan)(guan)的(de)(de)(de)(de)要(yao)(yao)求(qiu)(qiu)主要(yao)(yao)體現在對(dui)外(wai)形(xing)(xing)尺寸和表面質(zhi)(zhi)量的(de)(de)(de)(de)要(yao)(yao)求(qiu)(qiu)上。因(yin)此，采用何種(zhong)方式、何種(zhong)工藝加工生產不銹(xiu)(xiu)鋼瓦(wa)(wa)(wa)(wa)楞(leng)(leng)形(xing)(xing)板(ban)(ban)就成為(wei)(wei)保證其外(wai)形(xing)(xing)尺寸和質(zhi)(zhi)量的(de)(de)(de)(de)關(guan)鍵。其他性(xing)(xing)能（機械性(xing)(xing)能、耐腐蝕性(xing)(xing)能和焊接性(xing)(xing)能）主要(yao)(yao)取決于所(suo)選(xuan)用的(de)(de)(de)(de)材料(liao)。

1. 不銹鋼瓦楞形(xing)板外形(xing)尺寸

 從圖(tu)5-37和(he)圖(tu)5-39可以(yi)看出不銹鋼瓦楞形(xing)(xing)(xing)板(ban)的外表形(xing)(xing)(xing)狀(zhuang)(zhuang)是(shi)有(you)規律(lv)、周期(qi)性(xing)變化的，而且彎曲深度較小、形(xing)(xing)(xing)狀(zhuang)(zhuang)單一，不僅有(you)橫(heng)向(xiang)波(bo)(bo)紋，而且還(huan)有(you)縱(zong)向(xiang)波(bo)(bo)紋。所以(yi)說，其形(xing)(xing)(xing)狀(zhuang)(zhuang)既簡單又復雜，簡單是(shi)指形(xing)(xing)(xing)狀(zhuang)(zhuang)單一，有(you)規律(lv)；復雜是(shi)指不僅有(you)橫(heng)向(xiang)波(bo)(bo)紋，而且還(huan)有(you)縱(zong)向(xiang)波(bo)(bo)紋。這就給不銹鋼瓦楞形(xing)(xing)(xing)板(ban)的成(cheng)型(xing)帶(dai)來不小的難度，在成(cheng)型(xing)工藝上必(bi)須采取相應的工藝措施和(he)手段，方能保(bao)證(zheng)獲得要求(qiu)的外形(xing)(xing)(xing)尺寸和(he)成(cheng)型(xing)質量。

 圖(tu)5-39是不(bu)銹鋼瓦楞形(xing)板的實物照片(pian)，從圖(tu)片(pian)可以看出(chu)，不(bu)銹鋼瓦楞形(xing)板的外(wai)表和形(xing)狀是非常(chang)美觀、漂亮的，具有較高(gao)的觀賞性(xing)，如同工(gong)藝品(pin)、裝(zhuang)飾品(pin)。

 圖5-39不銹鋼瓦楞形板A-A截面尺(chi)寸(cun)，見圖5-40,B-B截面尺(chi)寸(cun)，見圖5-41。

 不銹鋼瓦楞形板成品實物斷面圖片，見圖5-40(b)和圖5-41(b)。

 從圖5-40和圖5-41可以看出，不銹鋼瓦楞形板(ban)的斷面變(bian)化的規律(lv)是(shi)周(zhou)期(qi)性的，斷面形狀是(shi)關于縱(zong)向(xiang)中心線為對(dui)稱的型鋼，彎曲深度較淺，深度僅有(you)7mm。

 不銹鋼瓦楞形(xing)板外形(xing)尺寸精度(du)：截面最大邊長誤(wu)差≤0.3mm;圓角最大直徑：≤2.0mm;縱向(xiang)、橫向(xiang)彎曲(qu)度(du)：每米≤1mm; 扭(niu)轉：每米≤1°。

2. 瓦楞形板橫向(xiang)波紋的成(cheng)型(xing)

 不(bu)銹鋼瓦楞形(xing)(xing)板(ban)輥(gun)(gun)(gun)式(shi)冷彎成(cheng)(cheng)(cheng)(cheng)型(xing)(xing)時，首先將不(bu)銹鋼冷軋平(ping)板(ban)預彎曲鐓(dui)壓成(cheng)(cheng)(cheng)(cheng)弧(hu)(hu)形(xing)(xing)波(bo)紋，如圖5-42所示的(de)第(di)一(yi)架(jia)成(cheng)(cheng)(cheng)(cheng)型(xing)(xing)輥(gun)(gun)(gun)孔形(xing)(xing)的(de)形(xing)(xing)狀。輥(gun)(gun)(gun)形(xing)(xing)的(de)形(xing)(xing)狀為(wei)(wei)，向(xiang)(xiang)下(xia)彎曲的(de)弧(hu)(hu)形(xing)(xing)直徑(jing)為(wei)(wei)Φ=265mm,向(xiang)(xiang)上彎曲的(de)弧(hu)(hu)形(xing)(xing)直徑(jing)為(wei)(wei)Φ=164mm,帶鋼進入并通過如此(ci)輥(gun)(gun)(gun)型(xing)(xing)是(shi)毫不(bu)困(kun)難的(de)，一(yi)個(ge)波(bo)長（周期）為(wei)(wei)83.40mm,弧(hu)(hu)深(shen)度（垂(chui)直位移）為(wei)(wei)4.12mm,這(zhe)個(ge)成(cheng)(cheng)(cheng)(cheng)型(xing)(xing)形(xing)(xing)狀無論是(shi)在變(bian)形(xing)(xing)寬(kuan)度上，還是(shi)變(bian)形(xing)(xing)深(shen)度上都是(shi)可行的(de)和符(fu)合要求的(de)。一(yi)個(ge)波(bo)長（周期）橫向(xiang)(xiang)位移（減(jian)寬(kuan)量）為(wei)(wei)0.60mm,相對減(jian)寬(kuan)率（橫向(xiang)(xiang)位移）為(wei)(wei)0.71%,見圖5-42,如此(ci)的(de)位移（減(jian)寬(kuan)量）不(bu)會對鐓(dui)壓成(cheng)(cheng)(cheng)(cheng)型(xing)(xing)造(zao)成(cheng)(cheng)(cheng)(cheng)困(kun)難和產生成(cheng)(cheng)(cheng)(cheng)型(xing)(xing)缺陷(xian)，這(zhe)些都為(wei)(wei)第(di)二架(jia)成(cheng)(cheng)(cheng)(cheng)型(xing)(xing)輥(gun)(gun)(gun)再鐓(dui)壓創造(zao)了條(tiao)件。

 第(di)(di)二架(jia)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)輥(gun)在第(di)(di)一(yi)(yi)架(jia)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)輥(gun)的(de)(de)(de)鐓壓(ya)(ya)基礎(chu)上(shang)，再(zai)次鐓壓(ya)(ya)，使其達到如圖5-42所(suo)(suo)示的(de)(de)(de)孔(kong)形(xing)形(xing)狀(zhuang)(zhuang)，弧(hu)度(du)直徑分(fen)別(bie)為Φ=133mm和(he)p=82mm,一(yi)(yi)個(ge)(ge)波(bo)長（周期(qi)）為81.70mm、弧(hu)深度(du)為8.18mm,這就是(shi)說寬(kuan)度(du)和(he)深度(du)更(geng)接(jie)近于(yu)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)品形(xing)狀(zhuang)(zhuang)，而(er)相(xiang)對(dui)減(jian)(jian)寬(kuan)量（水(shui)(shui)平(ping)位(wei)移）僅(jin)為1.42mm,相(xiang)對(dui)減(jian)(jian)寬(kuan)率（水(shui)(shui)平(ping)方(fang)向）為1.7%,要比第(di)(di)一(yi)(yi)道次大了(le)許(xu)多，這是(shi)符合開(kai)始(shi)小一(yi)(yi)些、中間大一(yi)(yi)些的(de)(de)(de)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)規律要求的(de)(de)(de)，見第(di)(di)三架(jia)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)輥(gun)在第(di)(di)二架(jia)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)輥(gun)的(de)(de)(de)鐓壓(ya)(ya)基礎(chu)上(shang)，再(zai)鐓壓(ya)(ya)，使其達到如圖5-42所(suo)(suo)示的(de)(de)(de)孔(kong)形(xing)形(xing)狀(zhuang)(zhuang)，這時將已(yi)(yi)經成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)的(de)(de)(de)弧(hu)形(xing)瓦(wa)楞形(xing)鐓壓(ya)(ya)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)梯形(xing)狀(zhuang)(zhuang)瓦(wa)楞形(xing)，而(er)一(yi)(yi)個(ge)(ge)波(bo)長（周期(qi)）為80mm,相(xiang)對(dui)減(jian)(jian)寬(kuan)量（水(shui)(shui)平(ping)位(wei)移）僅(jin)為2.28mm,一(yi)(yi)個(ge)(ge)波(bo)長（周期(qi)）相(xiang)對(dui)減(jian)(jian)寬(kuan)率（水(shui)(shui)平(ping)方(fang)向）為2.79%.通過(guo)鐓壓(ya)(ya)使弧(hu)深由8.18mm減(jian)(jian)小為7.00mm,這樣(yang)可使梯形(xing)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)更(geng)加精(jing)確(que)到位(wei)，為最后(hou)沖壓(ya)(ya)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)達到成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)品形(xing)狀(zhuang)(zhuang)及尺寸奠定良好的(de)(de)(de)基礎(chu)，此時，橫向鐓壓(ya)(ya)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)已(yi)(yi)全部(bu)完(wan)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)，隨后(hou)將采用沖壓(ya)(ya)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)輥(gun)在已(yi)(yi)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)橫向波(bo)紋上(shang)完(wan)成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)最終成(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)(xing)(xing)。

 圖(tu)5-42是各架次成型輥(gun)輥(gun)形(xing)尺寸圖(tu)。

 第三(san)架成型輥(gun)輥(gun)形圖(tu)(tu)和(he)孔形圖(tu)(tu)，見(jian)圖(tu)(tu)5-43.第三(san)架成型輥(gun)應(ying)是(shi)(shi)由多片(pian)輥(gun)片(pian)疊加(jia)組合(he)而成的(de)(de)(de)組合(he)輥(gun)，輥(gun)片(pian)的(de)(de)(de)水平(ping)段(duan)和(he)圓(yuan)弧段(duan)采取與板(ban)材(cai)接(jie)觸的(de)(de)(de)方(fang)式，而傾斜(xie)(xie)段(duan)則(ze)采取與板(ban)材(cai)不接(jie)觸的(de)(de)(de)方(fang)式，為的(de)(de)(de)是(shi)(shi)減少成型表面的(de)(de)(de)擦劃傷，此外，如此結構也將(jiang)便于成型輥(gun)的(de)(de)(de)加(jia)工和(he)隨后的(de)(de)(de)使用與維護(hu)等。上(shang)、下輥(gun)斜(xie)(xie)角采取圓(yuan)弧過渡，一般情況下，圓(yuan)弧的(de)(de)(de)直徑應(ying)大于板(ban)厚(hou)，所以圖(tu)(tu)5-43所示的(de)(de)(de)第三(san)架上(shang)、下輥(gun)斜(xie)(xie)角的(de)(de)(de)圓(yuan)弧過渡直徑為2.0mm,見(jian)圖(tu)(tu)5-43局部放大圖(tu)(tu)。

3. 縱向波紋的成(cheng)型

 縱(zong)向波(bo)(bo)(bo)紋(wen)(wen)的(de)成(cheng)(cheng)型(xing)(xing)(xing)是(shi)(shi)在(zai)橫向波(bo)(bo)(bo)紋(wen)(wen)成(cheng)(cheng)型(xing)(xing)(xing)之后的(de)橫向波(bo)(bo)(bo)紋(wen)(wen)上(shang)(shang)成(cheng)(cheng)型(xing)(xing)(xing)的(de)。所以在(zai)已成(cheng)(cheng)型(xing)(xing)(xing)的(de)波(bo)(bo)(bo)紋(wen)(wen)上(shang)(shang)再成(cheng)(cheng)型(xing)(xing)(xing)縱(zong)向波(bo)(bo)(bo)紋(wen)(wen)是(shi)(shi)有難度的(de)。其難度主要表現為，可能破壞已成(cheng)(cheng)型(xing)(xing)(xing)的(de)橫向波(bo)(bo)(bo)紋(wen)(wen)，而(er)且縱(zong)向波(bo)(bo)(bo)紋(wen)(wen)也成(cheng)(cheng)型(xing)(xing)(xing)不好。選用(yong)何種方(fang)式成(cheng)(cheng)型(xing)(xing)(xing)就成(cheng)(cheng)為縱(zong)向波(bo)(bo)(bo)紋(wen)(wen)成(cheng)(cheng)型(xing)(xing)(xing)的(de)關鍵(jian)。

 沖壓(ya)(ya)(ya)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)輥(gun)(gun)(gun)(gun)就是在(zai)(zai)一(yi)對成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)輥(gun)(gun)(gun)(gun)上，按(an)工藝和(he)(he)產品的(de)(de)(de)要求，在(zai)(zai)要面(mian)上間隙分(fen)布著凸起和(he)(he)凹陷(xian)的(de)(de)(de)部(bu)分(fen)，用(yong)于壓(ya)(ya)(ya)制(zhi)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)瓦(wa)(wa)楞形(xing)(xing)板(ban)(ban)(ban)(ban)的(de)(de)(de)縱向(xiang)波(bo)(bo)(bo)紋(wen)(wen)(wen)(wen)，同時又不能(neng)損壞已成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)的(de)(de)(de)橫(heng)向(xiang)梯形(xing)(xing)波(bo)(bo)(bo)紋(wen)(wen)(wen)(wen)，縱向(xiang)波(bo)(bo)(bo)紋(wen)(wen)(wen)(wen)尺(chi)寸圖及實物圖片，見圖5-40和(he)(he)圖5-41。之所以將沖壓(ya)(ya)(ya)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)輥(gun)(gun)(gun)(gun)置(zhi)于橫(heng)向(xiang)波(bo)(bo)(bo)紋(wen)(wen)(wen)(wen)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)輥(gun)(gun)(gun)(gun)后(hou)、平整輥(gun)(gun)(gun)(gun)前，是為了保(bao)證(zheng)瓦(wa)(wa)楞形(xing)(xing)板(ban)(ban)(ban)(ban)的(de)(de)(de)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)過程的(de)(de)(de)穩(wen)定和(he)(he)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)質量。可以想象，在(zai)(zai)沒有(you)(you)橫(heng)向(xiang)波(bo)(bo)(bo)紋(wen)(wen)(wen)(wen)的(de)(de)(de)平板(ban)(ban)(ban)(ban)帶材上沖壓(ya)(ya)(ya)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)凸起和(he)(he)凹陷(xian)型(xing)材，由(you)于自由(you)度大沒有(you)(you)約束力，沖壓(ya)(ya)(ya)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)會造成(cheng)(cheng)(cheng)(cheng)(cheng)坯料(liao)局部(bu)收縮，產生皺(zhou)折及其他缺陷(xian)，影響成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)質量和(he)(he)成(cheng)(cheng)(cheng)(cheng)(cheng)品的(de)(de)(de)尺(chi)寸。另外，瓦(wa)(wa)楞形(xing)(xing)板(ban)(ban)(ban)(ban)型(xing)鋼(gang)截面(mian)受材料(liao)內部(bu)殘余應(ying)力作(zuo)用(yong)，很容易(yi)產生扭(niu)轉(zhuan)，這也會影響成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)過程的(de)(de)(de)穩(wen)定性。但在(zai)(zai)瓦(wa)(wa)楞形(xing)(xing)板(ban)(ban)(ban)(ban)橫(heng)向(xiang)波(bo)(bo)(bo)紋(wen)(wen)(wen)(wen)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)輥(gun)(gun)(gun)(gun)后(hou)、平整輥(gun)(gun)(gun)(gun)前，再用(yong)沖壓(ya)(ya)(ya)輥(gun)(gun)(gun)(gun)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)其縱向(xiang)波(bo)(bo)(bo)紋(wen)(wen)(wen)(wen)，此時，已成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)的(de)(de)(de)橫(heng)向(xiang)波(bo)(bo)(bo)紋(wen)(wen)(wen)(wen)使瓦(wa)(wa)楞形(xing)(xing)板(ban)(ban)(ban)(ban)的(de)(de)(de)剛(gang)度增大，同時又受到(dao)(dao)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)輥(gun)(gun)(gun)(gun)和(he)(he)平整輥(gun)(gun)(gun)(gun)的(de)(de)(de)約束，其自由(you)度就減小。以上這些都可以有(you)(you)效(xiao)地防止(zhi)局部(bu)收縮和(he)(he)型(xing)鋼(gang)的(de)(de)(de)扭(niu)轉(zhuan)，從而(er)對保(bao)證(zheng)瓦(wa)(wa)楞形(xing)(xing)板(ban)(ban)(ban)(ban)的(de)(de)(de)成(cheng)(cheng)(cheng)(cheng)(cheng)型(xing)及質量起到(dao)(dao)有(you)(you)效(xiao)的(de)(de)(de)保(bao)障作(zuo)用(yong)。瓦(wa)(wa)楞形(xing)(xing)板(ban)(ban)(ban)(ban)橫(heng)向(xiang)波(bo)(bo)(bo)紋(wen)(wen)(wen)(wen)沖壓(ya)(ya)(ya)輥(gun)(gun)(gun)(gun)的(de)(de)(de)示(shi)意圖，見圖5-44。

 沖壓(ya)成(cheng)型輥(gun)也應做成(cheng)組合(he)式(shi)輥(gun)子，即(ji)由(you)多輥(gun)片疊(die)加(jia)組合(he)而(er)成(cheng)。這種形式(shi)的輥(gun)子便(bian)于(yu)加(jia)工和維護，調整使用(yong)方便(bian)。