Internal Geneva Mechanism
AIM
Today I am going to create 3D model of internal Geneva mechanism by the help of geven 2D CAD drawing using solidworks. Then performing motion analysis by rotating driver wheel and making plot.
GENEVA MECHANISM
A mechanism that translates a continuous rotation into an intermittent rotary motion, using an intermittent gear where the driving wheel(the wheel which is directly connected to motor ) has a pin that reaches into a slot of the driven wheel (the wheel which is connected to driver wheel and rotating by the help of driving wheel) and thereby advances it by one step, and having a raised circular blocking disc that locks the driven wheel in position between steps.
CREATEING PART FOR INTERNAL GENEVA MECHANISM
First we are going to create PART 01 GENEVA DRIVEN WHEEL
1 chosing front plane and click on sketch
2 using circle tool create 3 circle of d1120mm,d520mm(make contraction geomatry),d120mm
3 taking slot tool and make dimension of 40mm on smaller circle (d120mm).
4 after that we we fillet R50mm on corner of slot and smaller circle.
5 Exist sketch and extrude to 40 mm as given shape. And save as Geneva driven wheel.
FRONT VIEW
RIGTH VIEW
TOP VIEW
Finally we ae going to create PART 02 DRIVING WHEEL
1 taking front plane and draw two cicle one of d420mm and other of d40mm at a distance of 160 mm from origin.
2 Exist skecth and extrude to 20mm for plane and 60mm for slot from base of plane
3 save the part as geneva driving wheel.
FRONT VIEW
RIGTH VIEW
TOP VIEW
ASSEMBLY OF GENEVA MECHANISM PART
for performing motion analysis we have to assemble these two part by apply constrain along the axis and plane
1 for driver wheel we have fixed his axis alone top and rigth plane of assembly.
2 then we mate driver wheel backface with fornt fornt plane of assembly.
3 for driven wheel axis we provide a distance of 226.72mm from driver wheel axis.
4 mate with backface of driven wheel with fornt face of driver wheel.
Performing motion analysis by rotating the driver wheel at 10rpm
in motion analysis option in solidworks
for perfoming motion analysis we have to do the fllowing step before
1 connect motor to the driver wheel @10rpm
2 make contact between driver and driven wheel solid and apply material steel(dry)
3 we aslo apply gravity
VIDEO
PLOT
contact force between driver and driven wheel as function of time without Precise contact
contact force between driver and driven wheel as function of time with Precise contact
after seeing both we found that plot 2 is much smother than the plot1.
excel sheet for contact force between driver and driven wheel as function of time with Precise contact
| Contact_geneva driving wheel-1_geneva driven wheel-1_4 | ||
| Reaction Force8 (newton) | ||
| Frame | Time | Ref. Coordinate System: |
| 1 | 0.000 | 3.6897E+03 |
| 2 | 0.040 | 2.8310E+02 |
| 3 | 0.040 | 2.8310E+02 |
| 4 | 0.080 | 1.2619E+00 |
| 5 | 0.120 | 2.1407E+01 |
| 6 | 0.129 | 1.7954E+01 |
| 7 | 0.160 | 1.6812E+01 |
| 8 | 0.200 | 1.5332E+01 |
| 9 | 0.240 | 1.3147E+01 |
| 10 | 0.280 | 1.1487E+01 |
| 11 | 0.320 | 1.0075E+01 |
| 12 | 0.360 | 8.8692E+00 |
| 13 | 0.400 | 7.8361E+00 |
| 14 | 0.440 | 6.9470E+00 |
| 15 | 0.480 | 6.1786E+00 |
| 16 | 0.520 | 5.5118E+00 |
| 17 | 0.560 | 4.9310E+00 |
| 18 | 0.600 | 4.4232E+00 |
| 19 | 0.640 | 3.9777E+00 |
| 20 | 0.680 | 3.5855E+00 |
| 21 | 0.720 | 3.2391E+00 |
| 22 | 0.760 | 2.9321E+00 |
| 23 | 0.800 | 2.6592E+00 |
| 24 | 0.840 | 2.4159E+00 |
| 25 | 0.880 | 2.1984E+00 |
| 26 | 0.920 | 2.0033E+00 |
| 27 | 0.960 | 1.8279E+00 |
| 28 | 1.000 | 1.6697E+00 |
| 29 | 1.040 | 1.5266E+00 |
| 30 | 1.080 | 1.3969E+00 |
| 31 | 1.120 | 1.2790E+00 |
| 32 | 1.160 | 1.1715E+00 |
| 33 | 1.200 | 1.0732E+00 |
| 34 | 1.240 | 9.8314E-01 |
| 35 | 1.280 | 9.0038E-01 |
| 36 | 1.320 | 8.2411E-01 |
| 37 | 1.360 | 7.5363E-01 |
| 38 | 1.400 | 6.8831E-01 |
| 39 | 1.440 | 6.2760E-01 |
| 40 | 1.480 | 5.7100E-01 |
| 41 | 1.520 | 6.3669E-01 |
| 42 | 1.560 | 4.2515E-01 |
| 43 | 1.600 | 3.8876E-01 |
| 44 | 1.640 | 3.8410E-01 |
| 45 | 1.680 | 3.3431E-01 |
| 46 | 1.720 | 2.9615E-01 |
| 47 | 1.760 | 2.5776E-01 |
| 48 | 1.800 | 2.2140E-01 |
| 49 | 1.840 | 1.8630E-01 |
| 50 | 1.880 | 1.5241E-01 |
| 51 | 1.920 | 1.1953E-01 |
| 52 | 1.960 | 8.7542E-02 |
| 53 | 2.000 | 5.6406E-02 |
| 54 | 2.040 | 2.6530E-02 |
| 55 | 2.080 | 8.9988E-04 |
| 56 | 2.120 | 4.6661E-02 |
| 57 | 2.160 | 6.9381E-02 |
| 58 | 2.200 | 9.3231E-02 |
| 59 | 2.240 | 1.2889E-01 |
| 60 | 2.280 | 1.5801E-01 |
| 61 | 2.320 | 1.9153E-01 |
| 62 | 2.360 | 2.1775E-01 |
| 63 | 2.400 | 2.5062E-01 |
| 64 | 2.440 | 2.8285E-01 |
| 65 | 2.480 | 3.1720E-01 |
| 66 | 2.520 | 3.5274E-01 |
| 67 | 2.560 | 3.8979E-01 |
| 68 | 2.600 | 4.2850E-01 |
| 69 | 2.640 | 4.6912E-01 |
| 70 | 2.680 | 5.1185E-01 |
| 71 | 2.720 | 5.5697E-01 |
| 72 | 2.760 | 6.0475E-01 |
| 73 | 2.800 | 6.5549E-01 |
| 74 | 2.840 | 7.0953E-01 |
| 75 | 2.880 | 7.6725E-01 |
| 76 | 2.920 | 8.2904E-01 |
| 77 | 2.960 | 8.9538E-01 |
| 78 | 3.000 | 9.6678E-01 |
| 79 | 3.040 | 1.0438E+00 |
| 80 | 3.080 | 1.1271E+00 |
| 81 | 3.120 | 1.2174E+00 |
| 82 | 3.160 | 1.3155E+00 |
| 83 | 3.200 | 1.4223E+00 |
| 84 | 3.240 | 1.5389E+00 |
| 85 | 3.280 | 1.6664E+00 |
| 86 | 3.320 | 1.8063E+00 |
| 87 | 3.360 | 1.9601E+00 |
| 88 | 3.400 | 2.1294E+00 |
| 89 | 3.440 | 2.3165E+00 |
| 90 | 3.480 | 2.5236E+00 |
| 91 | 3.520 | 2.7534E+00 |
| 92 | 3.560 | 3.0090E+00 |
| 93 | 3.600 | 3.2942E+00 |
| 94 | 3.640 | 3.6132E+00 |
| 95 | 3.680 | 3.9710E+00 |
| 96 | 3.720 | 4.3733E+00 |
| 97 | 3.760 | 4.8272E+00 |
| 98 | 3.800 | 5.3407E+00 |
| 99 | 3.840 | 5.9234E+00 |
| 100 | 3.880 | 6.5870E+00 |
| 101 | 3.920 | 7.3450E+00 |
| 102 | 3.960 | 8.2140E+00 |
| 103 | 4.000 | 9.2138E+00 |
| 104 | 4.040 | 1.0368E+01 |
| 105 | 4.080 | 1.1707E+01 |
| 106 | 4.120 | 1.3264E+01 |
| 107 | 4.160 | 1.5085E+01 |
| 108 | 4.200 | 1.7221E+01 |
| 109 | 4.240 | 1.9740E+01 |
| 110 | 4.280 | 2.2722E+01 |
| 111 | 4.320 | 2.6270E+01 |
| 112 | 4.360 | 3.0509E+01 |
| 113 | 4.400 | 3.5599E+01 |
| 114 | 4.440 | 4.1736E+01 |
| 115 | 4.480 | 1.4039E-15 |
| 116 | 4.490 | 1.4183E-15 |
| 117 | 4.520 | 1.4615E-15 |
| 118 | 4.560 | 1.5191E-15 |
| 119 | 4.600 | 1.5767E-15 |
| 120 | 4.640 | 1.6343E-15 |
| 121 | 4.680 | 1.6919E-15 |
| 122 | 4.720 | 1.7495E-15 |
| 123 | 4.760 | 1.8071E-15 |
| 124 | 4.800 | 1.8647E-15 |
| 125 | 4.840 | 1.9222E-15 |
| 126 | 4.880 | 1.9798E-15 |
| 127 | 4.920 | 2.0374E-15 |
| 128 | 4.960 | 2.0950E-15 |
| 129 | 5.000 | 2.1526E-15 |
image for precise contact selection
Plot of Angular Displacement of the driven wheel
here we can see the angular displacement of driven wheel in 5 sec @10rpm. and also we see that the displacement vs time plot slop is nearly constant which means our driven wheel is well connected to our driver wheel
plot of the driver wheel's angular velocity @20rpm
here we can see the plot of angular velocity of driver wheel which seem to preety much constant. obviously because driver wheel conected to motot which is rotating with a constant velocity of 20rpm