安(an)全性。汽(qi)車(che)(che)起重機(ji)的(de)(de)安(an)全裝(zhuang)置是(shi)的(de)(de)，一個(ge)好的(de)(de)產品也是(shi)一個(ge)安(an)全性zui好的(de)(de)產品。汽(qi)車(che)(che)起重機(ji)安(an)全裝(zhuang)置主要有(you)起重力矩限(xian)制器(qi)、防過(guo)卷裝(zhuang)置（高度(du)限(xian)位(wei)器(qi)）、防過(guo)放裝(zhuang)置、吊鉤(gou)防脫鉤(gou)裝(zhuang)置、雙向液(ye)壓(ya)(ya)鎖、平衡閥(fa)及液(ye)壓(ya)(ya)溢(yi)流閥(fa)等，用戶在(zai)選擇時必須對車(che)(che)型的(de)(de)安(an)全性進行充分的(de)(de)了解。

關鍵(jian)件配(pei)(pei)置(zhi)(zhi)。主(zhu)要部件的(de)好壞(huai)關系(xi)到整車的(de)性能，它是汽車起(qi)重機良好運行(xing)的(de)基礎。在(zai)選(xuan)購汽車起(qi)重機時要對同(tong)(tong)類(lei)型汽車起(qi)重機進行(xing)比(bi)較quan面的(de)調查(cha)、多方(fang)比(bi)較，同(tong)(tong)一噸位也存在(zai)不(bu)(bu)(bu)同(tong)(tong)類(lei)型的(de)產品，齒輪(lun)泵廠家(jia)，要比(bi)較各型號產品的(de)優勢(shi)和(he)劣勢(shi)，做(zuo)到胸(xiong)有成竹。另外同(tong)(tong)類(lei)型汽車起(qi)重機有不(bu)(bu)(bu)同(tong)(tong)的(de)配(pei)(pei)置(zhi)(zhi)，用(yong)戶可根(gen)據需(xu)要選(xuan)用(yong)不(bu)(bu)(bu)同(tong)(tong)的(de)配(pei)(pei)置(zhi)(zhi)，山東齒輪(lun)泵，當然在(zai)選(xuan)用(yong)不(bu)(bu)(bu)同(tong)(tong)配(pei)(pei)置(zhi)(zhi)時，價(jia)格也不(bu)(bu)(bu)盡相同(tong)(tong)，用(yong)戶應根(gen)據自己的(de)需(xu)要進行(xing)配(pei)(pei)置(zhi)(zhi)，追求(qiu)zui好的(de)價(jia)格性能比(bi)。

一、起重機的供電特點

交(jiao)流起(qi)重(zhong)機(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)由公共的(de)(de)(de)交(jiao)流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)網供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，由于(yu)起(qi)重(zhong)機(ji)(ji)(ji)的(de)(de)(de)工作是經(jing)常(chang)(chang)移(yi)(yi)動(dong)的(de)(de)(de)，因此其與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)之(zhi)間不能(neng)采(cai)用固定連接方式，對于(yu)小(xiao)型起(qi)重(zhong)機(ji)(ji)(ji)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式采(cai)用軟電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，隨著(zhu)大車或小(xiao)車的(de)(de)(de)移(yi)(yi)動(dong)，供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜隨之(zhi)伸展和疊卷。對于(yu)一(yi)般(ban)橋式起(qi)重(zhong)機(ji)(ji)(ji)常(chang)(chang)用滑(hua)線和電(dian)(dian)(dian)(dian)(dian)(dian)(dian)刷供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。三相交(jiao)流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)接到(dao)沿車間長度方向架設的(de)(de)(de)三根主滑(hua)線上，再通過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)刷引到(dao)起(qi)重(zhong)機(ji)(ji)(ji)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)氣(qi)設備(bei)上，首入(ru)駕駛室中的(de)(de)(de)保護盤上的(de)(de)(de)總電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)開(kai)關，然后(hou)再向起(qi)重(zhong)機(ji)(ji)(ji)各電(dian)(dian)(dian)(dian)(dian)(dian)(dian)氣(qi)設備(bei)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。對于(yu)小(xiao)車及其上的(de)(de)(de)提升機(ji)(ji)(ji)構(gou)等電(dian)(dian)(dian)(dian)(dian)(dian)(dian)氣(qi)設備(bei)，則經(jing)位于(yu)橋架另一(yi)側的(de)(de)(de)輔(fu)助滑(hua)線來供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。

滑線(xian)通(tong)常用角(jiao)鋼、圓鋼、V形鋼軌來制成。當電(dian)(dian)流(liu)(liu)值很大或(huo)(huo)滑線(xian)太長時(shi)，為減少滑線(xian)電(dian)(dian)壓降，常將(jiang)角(jiao)鋼與鋁排逐斷(duan)并聯，以減少電(dian)(dian)阻值。在交(jiao)流(liu)(liu)系統中，圓鋼滑線(xian)因(yin)趨膚效(xiao)應的(de)影響，只適用于短(duan)線(xian)路或(huo)(huo)小電(dian)(dian)流(liu)(liu)的(de)供電(dian)(dian)線(xian)路。

二、電路構成

10t交流橋(qiao)式(shi)起重機電(dian)氣控(kong)(kong)制(zhi)的(de)全電(dian)路(lu)如圖8－10所示。10t橋(qiao)式(shi)起重機只有(you)一(yi)(yi)個(ge)吊(diao)鉤，但大車(che)采用分別(bie)驅動(dong)(dong)(dong)(dong)，所以共用了(le)四臺(tai)(tai)繞線(xian)轉子異步(bu)電(dian)動(dong)(dong)(dong)(dong)機拖(tuo)動(dong)(dong)(dong)(dong)。起重電(dian)動(dong)(dong)(dong)(dong)機M1、小車(che)驅動(dong)(dong)(dong)(dong)電(dian)動(dong)(dong)(dong)(dong)機M2、大車(che)驅動(dong)(dong)(dong)(dong)電(dian)動(dong)(dong)(dong)(dong)機M3和M4；分別(bie)由三只凸輪控(kong)(kong)制(zhi)器(qi)控(kong)(kong)制(zhi)：QM1控(kong)(kong)制(zhi)M1、QM2控(kong)(kong)制(zhi)M2、QM3同步(bu)控(kong)(kong)制(zhi)M3與(yu)M4；R1～R4分別(bie)為四臺(tai)(tai)電(dian)動(dong)(dong)(dong)(dong)機轉子電(dian)路(lu)串入的(de)調速電(dian)阻器(qi)；YB1～YB4則分別(bie)為四臺(tai)(tai)電(dian)動(dong)(dong)(dong)(dong)機的(de)制(zhi)動(dong)(dong)(dong)(dong)電(dian)磁鐵。三相電(dian)源由QS1引入，并由接觸器(qi)KM控(kong)(kong)制(zhi)。過(guo)流繼(ji)電(dian)器(qi)KI0～KI4提供過(guo)電(dian)流保(bao)護(hu)，其中(zhong)KI1～KI4為雙(shuang)線(xian)圈(quan)式(shi)，分別(bie)保(bao)護(hu)M1、M2、M3與(yu)M4；KI0為單線(xian)圈(quan)式(shi)，單獨串聯在主電(dian)路(lu)的(de)一(yi)(yi)相電(dian)源線(xian)中(zhong)，作(zuo)總電(dian)路(lu)的(de)過(guo)電(dian)流保(bao)護(hu)。

該(gai)電(dian)路的控制(zhi)原理(li)已在分(fen)析(xi)圖2-6時介紹(shao)過，不同(tong)的是凸輪控制(zhi)器QM3共(gong)有17對觸點，比QM1、QM2多(duo)了五對觸點，用于控制(zhi)另一臺(tai)(tai)電(dian)動機的轉子電(dian)路，因此可以同(tong)步控制(zhi)兩臺(tai)(tai)繞(rao)線轉子異步電(dian)動機。下面主要介紹(shao)該(gai)電(dian)路的保護電(dian)路部分(fen)。

一、小吊車液壓系統發熱的原因

1、油箱(xiang)容積太小，散熱面積不夠，未(wei)安(an)裝油冷卻(que)裝置(zhi)，或雖有冷卻(que)裝置(zhi)但其容量(liang)過小。

2、按快進速(su)度(du)選擇油泵容量(liang)的定量(liang)泵供油系統，在(zai)工(gong)作時會有大部(bu)分多余的liu量(liang)在(zai)高壓下從溢liu閥溢回而(er)發熱(re)。

3、系統中卸(xie)(xie)荷(he)回路(lu)出現故(gu)障或因未設置卸(xie)(xie)荷(he)回路(lu)，齒輪泵(beng)(beng)價格，停止(zhi)工作時油泵(beng)(beng)不能卸(xie)(xie)荷(he)，齒輪泵(beng)(beng)銷售(shou)，泵(beng)(beng)的全部流量在高(gao)壓下溢liu，產生(sheng)溢liu損失而發熱，導致油液(ye)發熱。

4、小(xiao)吊車系統管(guan)路過(guo)細(xi)過(guo)長，彎(wan)曲過(guo)多(duo)，局(ju)部壓力損(sun)失和沿程壓力損(sun)失大。

5、小吊(diao)車(che)元(yuan)件精(jing)度不夠及裝(zhuang)配質量差，相對運動間的機械(xie)摩擦損失大(da)。

6、配合件(jian)的配合間(jian)隙太小，或使用(yong)磨損后導(dao)致間(jian)隙過大，內、外(wai)泄(xie)漏(lou)量大，造成容積(ji)損失(shi)大，如泵的容積(ji)效率降低，發熱快。

7、液壓系統工作壓力調(diao)整得(de)比實際(ji)需要(yao)高(gao)。有時(shi)是因(yin)密封過(guo)緊，或因(yin)密封件損壞、泄(xie)漏增大(da)而不(bu)得(de)不(bu)調(diao)高(gao)壓力才能工作。

8、氣候(hou)及作(zuo)業(ye)環境溫度高(gao)，致使油溫升高(gao)。

9、選擇(ze)小吊(diao)車(che)油液的(de)粘度不當，粘度大粘性阻(zu)力大，粘度太(tai)小則泄漏增大，兩種情況均能造(zao)成油液發熱。