1、机械原理课程设计往复泵动力端运动机构设计和分析一、设计题目往复泵动力端运动机构设计和分析二、机构传动系统方案的确定1)功能要求:将原动机的高速旋转运动变为柱塞的低速往复运动2)工作原理:往复泵是利用工作腔容积的周期性变化来输送高压流体的,它通常由两部分组成。一部分直接输送液体,把机械能转换为液体的压力能的液力端,另一部分将原动机的能量传给液力端的动力端。动力端主要有曲柄、连杆、十字头等部件。如上图所示,在液缸中有柱塞杆和柱塞,液缸体上装有吸入阀和排出阀。液缸体中柱塞与阀之间的空间称为工作室,它通过吸入阀和排出阀分别与吸入管路和排出管相连。通常压裂泵的动力源为高速柴油机,动力由柴油机经过减速装置
2、传递到曲柄,当曲柄以角速度顺时针旋转时,柱塞从右极限位置开始向左运动,工作腔的容积增大,压力降低,液体在压力差的作用下克服吸入管路和吸入阀等的阻力损失进入液缸体中。当柱塞运动到左极限位置时,吸入液体过程停止,吸入阀关闭。曲柄继续旋转,柱塞开始向右运动,液缸体中的液体被挤压,液体压力急骤增加。在这一压力作用下,排出阀被打开,液缸体内液体在柱塞的作用下被排送到排出管路中去。当往复泵的曲轴以角速度不停旋转时,往复泵就实现连续吸入和排出液体的过程。往复泵的曲柄滑块机构一般采用对心式设计,在一些压力高或者由于结构的限制选定的长细比(R/L)值比较大的情况下,可以采用正偏置设计来改善十字头与导板间的正压力
3、和偏磨。柱塞行程s(mm)偏心距e(mm)最大压力角()柴油机转速(rpm)冲次N(冲/分)柱塞直径(mm)排出压力(MPa)十字头与导轨的摩擦系数f十字头质量(Kg)曲柄质量(Kg)连杆质量(Kg)2292452150012070450.13304070 3)原始数据和设计要求注:其它摩擦及其他构件质量均忽略不计;假定泵阀的滞后角为0;曲柄和连杆的质量与长度有关,本题假定为已知;吸入压力P2=0.01MPa。三、机构综合的方法和运算结果1)综合分析(1)齿轮传动的基本简图如上所示。 齿轮设计采用压力角为20的直齿圆柱齿轮,根据根切条件可知Zmax=17,且直齿圆柱齿轮的传动比一般在3-8。(
4、2)传动比的具体分配方案依题意有:n1=1500r/min,n4=120r/min i14=(-1)mZ2Z3Z4/Z1Z2Z3=Z4/Z1=n1/n4=1500/120=12.5因为传动比12.5大于8,所以应采取如图分级传动,取Z1=18,则Z4=300具体传动比分配如下: i12=Z2/Z1=5=n1/n2Z2=90,n2=300r/min齿轮2和3在同一轴上,则有:n3=n2=300r/min i34=Z4/Z3=5/2=n3/n4Z3=120综上所述:传动比的分配方案为,i12=5,i34=5/2(3)曲柄滑块机构的设计如图所示:点B运动到B1、B2位置是曲柄滑块机构运动的两极限位置
5、,当点B运动到B3位置(B3在A点正下方),压力角取最大值。由图中几何关系得: Sin52。=(e+R)/L (S+c)2+e2=L2整理得:L=(R+e)/ sin(52)L=(4S2R2-4S2e2- S4)/(16R2-4S2)1/22)主程序设计Private Sub picture1_Click()Picture1.ForeColor = RGB(255, 0, 0) Const Pi = 3.1415926Dim x!, y1!, y2!Picture1.Scale (-18, 18)-(18, -18)Picture1.Line (-14, 0)-(14, 0)Picture1.
6、Line (0, 14)-(0, -14)Picture1.CurrentX = 11.5: Picture1.CurrentY = -0.6: Picture1.Print X/dmPicture1.CurrentY = 14: Picture1.CurrentX = 0.6: Picture1.Print Y/dm2 For x = -8 To 8 Step 0.00005y1 = (x + 0.24) * (x + 0.24) / (Sin(52 * Pi / 180) * Sin(52 * Pi / 180)y2 = (4 * 2.29 * 2.29 * x * x - 4 * 2.2
7、9 *2.29 * 0.24 * 0.24 2.29 * 2.29 *2.29 * 2.29) / (16 * x * x - 4 *2.29 * 2.29) Picture1.PSet (x, y1) Picture1.PSet (x, y2) If Abs(y1 - y2) 0.0001 Then Picture1.Print Format(x, #0.#)Next xEnd Sub3)计算结果由程序运算结果可知: R=0.69303dm=69.3mm,从而L=(69.3+24)/sin( 52) =118.4mm四、运动分析的方法和计算结果1)运动分析由几何关系不难得出:c=(L-R)2
8、-e2)1/2=42.8mm, 1=2n则: 2=Rcos 1/Lcos(1)位置分析x=Rcos+Lcos+c由于Rsin+e=Lsin可知 所以 cos=1-(Rsin+e)2/L21/2也即有:x=Rcos+L1-(Rsin+e)2/L21/2+c又由 解之即有: (2)速度分析根据位置方程对时间求导可得:V=dx/dt=-R sin1-L sin2 =-R sin1- L sinR cos1/L cos =-R sin1-( R sin +e)R cos1/L)/1-(R sin +e)2/L21/2(3)加速度分析由题意可得:a=dv/dt=-R12cos-L(cos22+sin*)
9、又由于 =R1(-sincos1+ sincos2)/(Lcos2) =R1-sin1-(R sin+e)2/L21/21+(R sin+e)/L cos2/ L1-(R sin+e)2/L2即a=-R12cos-L(cos22+sinR1-sin1-(R sin+e)2/L21/21+(Rsin+e)/L cos2/ L1-(R sin+e)2/L2)3)往复泵的运动分析(1)位移图像分析Private Sub picture1_Click()Picture1.ForeColor = RGB(255, 0, 0) Dim x as double,y as double,n as double
10、,m as doublePicture1.ClsPicture1.Scale (-8, 4)-(8, -4) Picture1.Line (-8, 0)-(8, 0): Picture1.Line (0, 4)-(0,-4)Picture1.CurrentX = 6.2: Picture1.CurrentY = -0.2: Picture1.Print X/radPicture1.CurrentY= 4 :Picture1.CurrentX= 0.2: Picture1.Print Y/dmFor i=-7 to 7Picture1.Line (i, 0)-(i, 0.1)Picture1.C
11、urrentX = i - 0.2: Picture1.CurrentY = -0.1: Picture1.Print iPicture1.CurrentX = -0.1: Picture1.CurrentY = i-0.1: Picture1.Print iNext iFor x = 0 To 6.283 Step 0.0001y = 0.693* Cos(x) +1.184 * Sqr(1 - (0.693* Sin(x) + 0.24) * (0.693 * Sin(x) + 0.24)/ (1.184 * 1.184) + 0.428Picture1.PSet (x, y)Next x
12、End sub运行结果如图所示:(2)速度图像分析 Private Sub picture1_Click()Picture1.ForeColor = RGB(255, 0, 0) Dim x as double,y as double,n as double,m as double Picture1.Cls Picture1.Scale (-8, 15)-(8, -15) Picture1.Line (-8, 0)-(8, 0): Picture1.Line (0,15)-(0, -15) Picture1.CurrentX = 6.2: Picture1.CurrentY = 0.2: Pi
13、cture1.Print X/rad Picture1.CurrentX = 0.2: Picture1.CurrentY =15: Picture1.Print Y/dm/sFor i = -14 To 14 Picture1.Line (i, 0)-(i, 0.1) Picture1.CurrentX = i - 0.2: Picture1.CurrentY = -0.1: Picture1.Print iPicture1.CurrentX = - 0.1: Picture1.CurrentY =i -0.1: Picture1.Print iNext iFor x = 0 To 6.28
14、3 Step 0.0001 n = (0.693 * Sin(x) + 0.24) /1.184 m = 0.693 * Cos(x) * 9.425 / (1.184* Sqr(1 - n * n) y = (-0.693) * Sin(x) * 9.425 1.184 * n * m Picture1.PSet (x, y)Next xEnd sub运行结果如图所示:(3)加速度图像分析Private Sub picture1_Click()Picture1.ForeColor = RGB(255, 0, 0) Dim x as double,y as double,n as double
15、,m as double Picture1.Cls Picture1.Scale (-8, 20)-(8, -20) Picture1.Line (-8, 0)-(8, 0): Picture1.Line (0, 20)-(0, -20) Picture1.CurrentX = 6.2: Picture1.CurrentY = 0.2: Picture1.Print X/rad Picture1.CurrentX = 0.2: Picture1.CurrentY =20: Picture1.Print Y /m/s2For i = -20 To 20 Picture1.Line (i, 0)-
16、(i, 0.1) Picture1.CurrentX = i - 0.2: Picture1.CurrentY = -0.1: Picture1.Print iPicture1.CurrentX = - 0.1: Picture1.CurrentY = i-0.1: Picture1.Print iNext iFor x = 0 To 6.283 Step 0.0001 n = (0.0693 * Sin(x) + 0.024) / 0.1184 m = 0.0693 * Cos(x) * 9.425 / (0.1184 * Sqr(1 - n * n) w = 0.0693* 9.425 *
17、 (-Sin(x) * Sqr(1 - n * n) * 9.425 + n * Cos(x) * m) / (0.1184* (1 - n * n) y = (-0.0693) * 9.425 * 9.425 * Cos(x) 0.1184 * (Sqr(1 - n * n) * m * m + n * w)Picture1.PSet (x, y)Next xEnd Sub运行结果如图所示:4)数据表格根据原始数据和所学参数,应用excel的计算功能可得往复泵的各个工作参数,如下表所示:。S mmV mm/sa mm/s2。 rad/s0228.0421-135.2025-9993.1197
18、8.13965.63346.569315220.4632-407.9960-9453.20421.71255.6979-7.352430205.6686-649.1253-7698.39581.71255.4996-22.868545185.0184-823.5475-4635.6752-16.6664.9546-40.376860160.8764-894.5296-284.0427-27.93633.9146-59.495075136.5566-833.65344619.4471-36.29642.2296-76.851390115.6950-653.15367879.1592-38.544
19、31.1358-84.4498105100.6842-428.14217806.0352-35.3453-2.2296-76.85112091.5763-236.76485871.9515-29.2911-3.9145-59.495213587.0134-100.15024070.1898-22.3286-4.9546-40.377015085.6374-4.02752964.0545-15.3150-5.4996-22.868716586.585869.89902439.2056-15.3109-5.6979-7.352618089.4420135.20192318.8045-1.9021-
20、5.63346.569119594.1059201.40132489.47584.4984-5.335519.2524210100.7044275.48872873.740010.6832-4.796930.7853225109.5274362.06883364.185016.5252-3.990840.9153240120.9392461.36383738.326321.7305-2.895549.0509255135.2032565.11033609.036925.8143-1.532154.4005270152.1911653.15152549.265828.1914-2.270656.
21、2747285171.0755696.6818422.511328.43471.532051.1834300190.2390669.9291-2417.583126.56372.895449.0511315207.5322561.6296-5341.607323.07373.990740.9156330220.7354377.6670-7788.654718.62094.796930.7856345227.9832136.6996-9402.905513.63775.335519.2528360228.0421-135.1972-9993.119013.63775.63346.5695五、对课
22、程设计进行总结做了两周的课程设计,有很多的心得体会,既有关于往复泵设计分析方面的,更多的是关于在设计过程中所体会的收获与成长。拿到题目时的第一感觉是不知所措的,感觉无从下手,致使一直放到快交时还有很多没做完,加上复习和各种上机作业,简直有点手忙脚乱,后来没办法只好静下心来慢慢做,我通过自己的努力,在反复的尝试和修改中,终于把整个计算和主要程序编写完成了,实现了预定的功能,以前的vb语言没学扎实,致使常常不能得心应手,一开始的程序这块儿就令我有些迷茫。后来经过几天几夜的努力,终于有了点头绪,然后又在同学的帮助下,找到了一些参考书,在各种资源的支持下我掌握了程序设计的各种方法,了解了往复泵的更多细
23、节,也理解了在编译过程中常常出现的问题和解决的方法。两个多星期后我的程序终于完成了。在机房调试虽然出现了一些问题,但都解决了。最后,我发现自己对编程竟然也有了一点兴趣,想暑假回家以后自己去买一些东西来做,再补一补c语言。六、主要参考文献往复泵设计编写组.往复泵设计M.北京:机械工业出版社,1987.朱修传.往复泵总体设计中主要参数的确定J.煤矿机械.2007.28(4):29-31.贾光政,王宣银.液压驱动往复泵的设计特点J.液压与气动.2002(2):44-46.七、附件(计算程序等).1)曲柄滑块机构的设计Private Sub picture1_Click()Picture1.ForeC
24、olor = RGB(255, 0, 0) Const Pi = 3.1415926Dim x!, y1!, y2!Picture1.Scale (-18, 18)-(18, -18)Picture1.Line (-14, 0)-(14, 0)Picture1.Line (0, 14)-(0, -14)Picture1.CurrentX = 11.5: Picture1.CurrentY = -0.6: Picture1.Print X/dmPicture1.CurrentY = 14: Picture1.CurrentX = 0.6: Picture1.Print Y/dm2 For x =
25、 -8 To 8 Step 0.00005y1 = (x + 0.24) * (x + 0.24) / (Sin(52 * Pi / 180) * Sin(52 * Pi / 180)y2 = (4 * 2.29 * 2.29 * x * x - 4 * 2.29 *2.29 * 0.24 * 0.24 2.29 * 2.29 *2.29 * 2.29) / (16 * x * x - 4 *2.29 * 2.29) Picture1.PSet (x, y1) Picture1.PSet (x, y2) If Abs(y1 - y2) 0.0001 Then Picture1.Print Fo
26、rmat(x, #0.#)Next xEnd Sub2)往复泵的运动分析(1)位移图像分析Private Sub picture1_Click()Picture1.ForeColor = RGB(255, 0, 0) Dim x as double,y as double,n as double,m as doublePicture1.ClsPicture1.Scale (-8, 4)-(8, -4) Picture1.Line (-8, 0)-(8, 0): Picture1.Line (0, 4)-(0,-4)Picture1.CurrentX = 6.2: Picture1.Curren
27、tY = -0.2: Picture1.Print X/radPicture1.CurrentY= 4 :Picture1.CurrentX= 0.2: Picture1.Print Y/dmFor i=-7 to 7Picture1.Line (i, 0)-(i, 0.1)Picture1.CurrentX = i - 0.2: Picture1.CurrentY = -0.1: Picture1.Print iPicture1.CurrentX = -0.1: Picture1.CurrentY = i-0.1: Picture1.Print iNext iFor x = 0 To 6.2
28、83 Step 0.0001y = 0.693* Cos(x) +1.184 * Sqr(1 - (0.693* Sin(x) + 0.24) * (0.693 * Sin(x) + 0.24)/ (1.184 * 1.184) + 0.428Picture1.PSet (x, y)Next xEnd sub(2)速度图像分析Private Sub picture1_Click()Picture1.ForeColor = RGB(255, 0, 0) Dim x as double,y as double,n as double,m as doublePicture1.ClsPicture1.
29、Scale (-8, 15)-(8, -15)Picture1.Line (-8, 0)-(8, 0): Picture1.Line (0,15)-(0, -15)Picture1.CurrentX = 6.2: Picture1.CurrentY = 0.2: Picture1.Print X/radPicture1.CurrentX = 0.2: Picture1.CurrentY =15: Picture1.Print Y/dm/sFor i = -14 To 14Picture1.Line (i, 0)-(i, 0.1)Picture1.CurrentX = i - 0.2: Picture1.CurrentY = -0.1: Picture1.Print iPicture1.CurrentX = - 0.1: Picture1.CurrentY =i -0.1: Picture1.Print iNext iFor x = 0 To 6.283 Step 0.0001
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