螺旋千斤顶说明书

精品精品可编辑可编辑精品可编辑螺旋千斤顶设计计算说明书院系工程技术学院专业年级机械设计制造及其自动化2009级2班设计者王刚指导教师杨玲成绩2011年11月28日精品精品可编辑可编辑精品可编辑螺旋千斤顶设计任务书学生姓名王刚专业年级机械设计制造及其自动化2009级设计题目：设计螺旋千斤顶SKIPIF1<0设计条件：1、最大起重量F=65kN；2、最大升距H=240mm。设计工作量：绘制出总装配图一张，标注有关尺寸，填写标题栏及零件明细表；编写设计计算说明书一份。指导教师签名：20年月日精品精品可编辑可编辑精品可编辑目录1螺杆的设计与计算··················································································································31.1螺杆螺纹类型选择····································································································31.2选取螺杆材料·············································································································31.3确定螺杆直径·············································································································31.4自锁验算······················································································································31.5结构································································································································41.6螺杆强度计算·············································································································精品精品可编辑可编辑精品可编辑41.7稳定性计算··················································································································51.7.1计算柔度·········································································································61.7.2计算稳定性····································································································62螺母设计与计算······················································································································62.1选取螺母材料·············································································································62.2确定螺母高度H¢及螺纹工作圈数u······································································62.2.1求螺母高度H¢································································································精品精品可编辑可编辑精品可编辑72.2.2螺纹工作圈数u·····························································································72.2.3螺母实际高度H¢····························································································72.3校核螺纹牙强度·········································································································72.4结构要求······················································································································83托杯的设计与计算··················································································································84手柄设计与计算······················································································································94.1手柄材料····················································································································精品精品可编辑可编辑精品可编辑104.2手柄长度Lp···············································································································104.3手柄直径dp···············································································································114.4结构·····························································································································115底座设计··································································································································12参考资料·····································································································································13螺旋千斤顶设计计算及说明结果精品精品可编辑可编辑精品可编辑1螺杆的设计与计算1.1螺杆螺纹类型的选择螺纹有矩形、梯形与锯齿形，常用的是梯形螺纹。梯形螺纹牙型为等腰梯形，牙形角α=30º，梯形螺纹的内外螺纹以锥面贴紧不易松动。故选梯形螺纹，它的基本牙形按GB/T5796.1—2005的规定。1.2选取螺杆材料螺杆材料常用Q235、Q275、40、45、55等。1.3确定螺杆直径按耐磨性条件确定螺杆中径d2。求出d2后，按标准选取相应公称直径d、螺距t及其它尺寸。有d2≥SKIPIF1<0根据国家规定SKIPIF1<0=1.2~3.5，取SKIPIF1<0=1.2（梯形螺纹）；h=0.5t；查教材表5-12，[p]取20Mpa。故，d2≥SKIPIF1<0=0.8SKIPIF1<0=41.5mm查机械设计课程设计手册，d取48mm，t=8mm，d1=39mm，d2=44mm1.4自锁验算自锁条件是≤v，式中：为螺纹中径处升角；v为当量摩擦角（当量摩擦角v=arctanv，但为保证自锁，螺纹中径处升角至少要比当量摩擦角小1°。查教材表5-12，f取0.09=SKIPIF1<0arctan(t/d2)=arctan[8/(3.14SKIPIF1<0)]=2.88°v=arctan（f/cosβ）=arctan[0.09/cos(30°/2)]=5.35°选梯形螺纹选40钢d=48mmt=8mmd1=39mmd2=44mm=2.88°v=5.35°<v-1°精品精品可编辑可编辑精品可编辑则=2.88°<v-1°=4.35°满足自锁条件1.5结构如下图（1-2）:螺杆上端用于支承托杯10并在其中插装手柄7，因此需要加大直径。手柄孔径dk的大小根据手柄直径dp决定，dk≥dp十0.5mm。为了便于切制螺纹，螺纹上端应设有退刀槽。退刀槽的直径d4应比螺杆小径d1约小0.2~0.5mm。退刀槽的宽度可取为1.5t。为了便于螺杆旋入螺母，螺杆下端应有倒角或制成稍小于d1的圆柱体。为了防止工作时螺杆从螺母中脱出，在螺杆下端必须安置钢制挡圈(GB/T891-1986)，挡圈用紧定螺钉(GB/T68-2000)固定在螺杆端部。其中：1.5t=12mmd4=38.5mmD13=(1.7~1.9)d=87mm(1.4~1.6)d=72mm0.25d=0.25×48mm=12mmd+(6~10)=48+8=56mm 1.6螺杆强度计算对受力较大的螺杆应根据第四强度理论校核螺杆的强度。强度计算方法参阅教材公式(5-47)，满足自锁条件1.5t=12mmd4=38.5mmD13=87mm(1.4~1.6)d=72mm0.25d=12mmd+(6~10)=56mm精品精品可编辑可编辑精品可编辑ca=SKIPIF1<0≤[]其中扭矩 =65×103×tan(2.88°+5.35°)×44/2N·mm=206830N·mm查机械设计课程设计手册，对40钢，SKIPIF1<0=335MPa由表5-13，[]=SKIPIF1<0=SKIPIF1<0=SKIPIF1<0=83.75MPad1=39mm，故，ca=SKIPIF1<0=62.50MPa≤[]=83.75MPa满足强度条件1.7稳定性计算细长的螺杆工作时受到较大的轴向压力可能失稳，为此应按稳定性条件验算螺杆的稳定性。SKIPIF1<0Fcr/F2.5~4螺杆的临界载荷Fcr与柔度λs有关，λs=l/i，为螺杆的长度系数，与螺杆的端部结构有关，l为举起重物后托杯底面到螺母中部的高度，可近似取l＝H+5t+(1.4~1.6)d，i为螺杆危险截面的惯性半径，若危险截面面积A=d12/4，则SKIPIF1<0(I为螺杆危险截面的轴惯性矩)当螺杆的柔度λs＜40时，可以不必进行稳定性校核。计算时应注意正确确定。1.7.1计算柔度T=206830N·mmSKIPIF1<0=335Mpa[]=83.75MPaca=62.50MPaca＜[]满足强度条件精品精品可编辑可编辑精品可编辑（1）计算螺杆危险截面的轴惯性矩I和iI=SKIPIF1<0=SKIPIF1<0=113560mm4SKIPIF1<0=SKIPIF1<0=9.75mm（2）求起重物后托杯底面到螺母中部的高度ll＝H+5t+(1.4~1.6)d=240+5×8+1.5×48=352mm(3)计算柔度查教材表5-14，μ取2(一端固定，一端自由)查教材公式5-51，E=2.06×105MPaλs=l/i=SKIPIF1<0=72.240，所以需要进行稳定性校核。1.7.2计算稳定性（1）计算临界载荷FcrSKIPIF1<0Fcr=SKIPIF1<0=465850N(2)稳定性计算SKIPIF1<0SKIPIF1<0=7.13.5~5满足稳定性条件。2螺母设计与计算2.1选取螺母材料螺母材料一般可选用青铜，对于尺寸较大的螺母可采用钢或铸铁制造，其内孔浇注青铜或巴氏合金。2.2确定螺母高度H及螺纹工作圈数uI=113560mm4i=9.75mml=352mmλs=72.2Fcr=465850NSKIPIF1<0=7.13.5~5满足稳定性条件选铸锡青铜ZCuSn10P1精品精品可编辑可编辑精品可编辑螺母高度H=φd2，螺纹工作圈数SKIPIF1<0，考虑退刀槽的影响，实际螺纹圈数u=u+1.5(u应圆整)。考虑到螺纹圈数u越多，载荷分布越不均，故u不宜大于10，否则应改选螺母材料或加大d。螺母高度由下式计算：H=ut。2.2.1初求螺母高度HH=φd2=1.2×44=52.8mm2.2.2螺纹工作圈数uSKIPIF1<0=SKIPIF1<0=6.6<10，符合要求u=u+1.5=6.6+1.5=8.1u应圆整,u取82.2.3螺母实际高度HH=ut=8×8=64mm2.3校核螺纹牙强度一般螺母的材料强度低于螺杆，故只校核螺母螺纹牙的强度。螺母的其它尺寸见图1―3。必要时还应对螺母外径D3进行强度验算。查教材公式5-48,5-49，螺纹牙的剪切强度和弯曲强度条件分别为：SKIPIF1<0；SKIPIF1<0式中：b为螺纹牙根部的厚度，对于梯形螺纹，b=0.65t;SKIPIF1<0为弯曲力臂，SKIPIF1<0=（D-D2）/2;查机械设计课程设计手册表3-8，D=d+1=49mm,D2=44mm查表5-13，SKIPIF1<0取30Mpa,SKIPIF1<0取40MpaH=48mmu=6.6u=8精品精品可编辑可编辑精品可编辑故，SKIPIF1<0SKIPIF1<0=SKIPIF1<0=10.15MPa<30MpaSKIPIF1<0SKIPIF1<0=SKIPIF1<0=29.28Mpa<40Mpa满足强度条件2.4结构要求螺母压入底座上的孔内，圆柱接触面问的配合常采用SKIPIF1<0或SKIPIF1<0等配合。为了安装简便，需在螺母下端（图1―3）和底座孔上端（图1―7）做出倒角。为了更可靠地防止螺母转动，还应装置紧定螺钉（图1―1），紧定螺钉直径常根据举重量选取，一般为6～12mm。螺母的相关尺寸计算D=d+1=49mmD3=(1.6~1.8)D=1.7×49mm=83mmD4=(1.3~1.4)D3=1.4×83mm=117mmH′=64mma=H′/3=64/3=21.3mm3托杯的设计与计算SKIPIF1<010.15MpaSKIPIF1<029.28Mpa满足强度条件D=49mmD3=83mmD4=117mma=21.3mm精品精品可编辑可编辑精品可编辑托杯用来承托重物，可用铸钢铸成，也可用Q235钢模锻制成，其结构尺寸见图1―4。为了使其与重物接触良好和防止与重物之间出现相对滑动，在托杯上表面制有切口的沟纹。为了防止托杯从螺杆端部脱落，在螺杆上端应装有挡板。当螺杆转动时，托杯和重物都不作相对转动。因此在起重时，托杯底部与螺杆和接触面间有相对滑动，为了避免过快磨损，一方面需要润滑，另一方面还需要验算接触面间的压力强度。SKIPIF1<0≤[p]（式1-1）式中：[p]——许用压强，应取托杯与螺杆材料[p]的小者。[p]取20Mpa图中δ取10mm，尺寸计算：D10=(2.4~2.5)d=2.5SKIPIF1<048=120mmD11=(0.6~0.7）d=0.65SKIPIF1<048=31.2mm圆整为32mmD13=(1.7~1.9)d=1.8SKIPIF1<048=86.4mm圆整为87mmD12=D13-(2~4)=87-3=84mm故SKIPIF1<0≤[SKIPIF1<0]=SKIPIF1<0=13.72Mpa<20Mpa4手柄设计与计算δ=10mmD10=120mmD11=32mmD13=87mmD12=84mmSKIPIF1<0=13.72MPa<[SKIPIF1<0]满足压力强度条件选Q235精品精品可编辑可编辑精品可编辑4.1手柄材料常用Q235和Q215。4.2手柄长度Lp板动手柄的力矩：SKIPIF1<0K·Lp=T1+T2则SKIPIF1<0（式1-2）式中：K——加于手柄上一个工人的臂力，间歇工作时，约为150～250N，工作时间较长时为100～150N。T1——螺旋副间的摩擦阻力矩，=65×103×tan(2.88°+5.35°)×SKIPIF1<0=206830N·mmT2——托杯与轴端支承面的摩擦力矩，T2=(D12+D11)fF/4。(查机械设计课程设计手册表1-10，对于钢-钢的摩擦因数f=0.1)=(84+32)×0.1×65SKIPIF1<0/4=188500N·mm则SKIPIF1<0(K取200)=SKIPIF1<0=1976.5mm手柄计算长度Lp是螺杆中心到人手施力点的距离，考虑螺杆头部尺寸及工人握手距离，手柄实际长度还应加上SKIPIF1<0+（50～150）mm。手柄实际长度不应超过千斤顶，使用时可在手柄上另加套管。T1=206830N·mmT2=188500N·mSKIPIF1<0=1976.5mmSKIPIF1<0=2120mm精品精品可编辑可编辑精品