起重机设计的总体方案Overall scheme of crane design

本次起重机设计的主要参数如下:

起重量20t,跨度15.5m，起升高度为11m起升速度8m/min小车运行速度v=40m/min大车运行速度V=90m/min大车运行传动方式为分别传动;桥架主梁型式,箱形梁.小车估计重量4t，起重机的重量16.0t .工作类型为中级。

根据上述参数确定的总体方案如下：

主梁的设计：

主梁跨度15.5m ,是由上、下盖板和两块垂直的腹板组成封闭箱形截面实体板梁连接，主梁横截面腹板的厚度为6mm,翼缘板的厚度为10mm，主梁上的走台的宽度取决于端梁的长度和大车运行机构的平面尺寸，主梁跨度中部高度取H=L/17 ，主梁和端梁采用搭接形式，主梁和端梁连接处的高度取H0=0.4-0.6H，腹板的稳定性由横向加劲板和，纵向加劲条或者角钢来维持，纵向加劲条的焊接采用连续点焊，主梁翼缘板和腹板的焊接采用贴角焊缝，主梁通常会产生下挠变形，但加工和装配时采用预制上拱。

小车的设计：

小车主要有起升机构、运行机构和小车架组成。

起升机构采用闭式传动方案，电动机轴与二级圆柱齿轮减速器的高速轴之间采用两个半齿联轴器和一中间浮动轴联系起来，减速器的低速轴鱼卷筒之间采用圆柱齿轮传动。

运行机构采用全部为闭式齿轮传动，小车的四个车轮固定在小车架的四周，车轮采用带有角形轴承箱的成组部件，电动机装在小车架的台面上，由于电动机轴和车轮轴不在同一个平面上，所以运行机构采用立式三级圆柱齿轮减速器，在减速器的输入轴与电动机轴之间以及减速器的两个输出轴端与车轮轴之间均采用带浮动轴的半齿联轴器的连接方式。

小车架的设计，采用粗略的计算方法，靠现有资料和经验来进行，采用钢板冲压成型的型钢来代替原来的焊接横梁。

端梁的设计：

端梁部分在起重机中有着重要的作用，它是承载平移运输的关键部件。端梁部分是由车轮组合端梁架组成，端梁部分主要有上盖板，腹板和下盖板组成；端梁是由两段通过连接板和角钢用高强螺栓连接而成。在端梁的内部设有加强筋，以保证端梁架受载后的稳定性。端梁的主要尺寸是依据主梁的跨度，大车的轮距和小车的轨距来确定的；大车的运行采用分别传动的方案。

在装配起重机的时候，先将端梁的一段与其中的一根主梁连接在一起，然后再将端梁的两段连接起来。

The main parameters of the crane design are as follows:

Weight of 20t, and span. L height 11m litre speed 8m / min car running speed v=40m/min cart running speed V=90m/min cart running transmission mode for transmission we; bridge girder type, box girder. The car is estimated weight 4T, the weight of the crane 16.0t. Type of work for intermediate.

The overall scheme identified according to the above parameters is as follows:

Design of main beam:

The span of 15.5m, is composed of an upper and a lower cover plate and two pieces of vertical web closed box section beam solid plate connection, the cross section of the plate thickness is 6mm, the flange thickness is 10mm, the main beam plane size go depending on the width of the end beam and the length of the crane traveling mechanism, the central span of girder the height of H=L/17, the main girder and end girder by lapping, height H0=0.4-0.6H girder and end girder connection, by transverse stiffened plate and the stability of web, longitudinal stiffeners or angle to maintain longitudinal stiffeners welded by continuous welding, flange and web girder welded by fillet weld, the girder will usually produce under the deflection, but the processing and assembly of prefabricated arch.

Design of car:

The car is mainly composed of lifting mechanism, operating mechanism and small frame.

Hoisting mechanism adopts a closed type transmission scheme, between the shaft of the motor is connected with two cylindrical gear reducer of the high-speed shaft by two and a half gear coupling and an intermediate floating shaft link, the reducer of the low speed shaft fish between the reel with cylindrical gear transmission.

Run organizations to adopt all closed type gear transmission, the car of the four wheels fixed around the small frame, wheels used with angular bearing box group member, a motor is arranged in the small frame on the table, due to the motor shaft and the wheel axis does not in the same plane, so the transport mechanism adopts vertical three-stage cylindrical gear reducer, the input shaft of the reducer shaft motor and reducer two output end of the shaft and wheel shaft and are used with floating shaft half gear shaft coupling connection.

The design of small frame, using rough calculation method, by the existing information and experience to carry out, using steel stamping forming steel to replace the original welding beam.

End beam design:

The end beam part plays an important role in the crane, which is the key component of the load shifting and transportation. End part of the beam is composed of wheel assembly end beam, end beam part is mainly on the cover, composed of web and bottom cover plate; end beam is formed by two segments through a connecting plate and angle steel with high strength bolt connection and. A reinforcing rib is arranged in the inner end of the beam to ensure the stability of the beam end by load. Main dimensions of the beam end is according to the span of the main girder, the cart track and car, the gauge to determine the; the cart running the transmission scheme, respectively.

When assembling the crane, the first section of the end beam is connected with one of the main beams, and the two section of the end beam is connected together.