Automatic Transmission Model
por emmett
Archivos imprimibles (21)
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stlgears.stl
2.1 Mo · 143 045 descargas
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stlplanets.stl
2.4 Mo · 141 105 descargas
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stlstand.stl
135 Ko · 139 880 descargas
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stlshaft.stl
689 Ko · 139 565 descargas
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stlcrank.stl
128 Ko · 139 127 descargas
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stlpins.stl
94 Ko · 139 300 descargas
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stlhandle.stl
87 Ko · 138 920 descargas
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stlcarrier.stl
721 Ko · 139 042 descargas
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stlanulus.stl
4.2 Mo · 138 766 descargas
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stlsun.stl
1.7 Mo · 138 627 descargas
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stlidler.stl
603 Ko · 138 155 descargas
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stlplanet1.stl
794 Ko · 138 022 descargas
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stlplanet2.stl
1.2 Mo · 137 973 descargas
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stlback.stl
121 Ko · 137 696 descargas
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stlfront.stl
119 Ko · 137 589 descargas
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stlbrace.stl
102 Ko · 137 579 descargas
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stlpin1.stl
117 Ko · 137 370 descargas
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stlpin2.stl
119 Ko · 137 262 descargas
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stlpin3.stl
111 Ko · 137 350 descargas
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stlback_loose.stl
127 Ko · 137 214 descargas
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stlfront_loose.stl
125 Ko · 137 061 descargas
Descripción
Have you ever wondered how an automatic transmission works? I did, so I looked it up and then designed this desktop model. It has six forward speeds and one reverse. Real automatic transmissions have a hydraulic or electrical system that engages different clutches and brakes to shift gears depending on the driving situation. With this model you control those simplified brakes and clutches yourself.
The clutch is actuated by sliding the drive shaft through to different positions (which each have two gear markings), while three separate brakes each also have two gear markings. You select a gear by engaging the brake and clutch position associated with your desired gear. See demonstration video: http://www.youtube.com/watch?v=-FyC3dn3HJY
I tried to design the gear ratios to be fairly close to what some real cars use, and this is the result, where the input is the crank and the output is the annulus:
1st gear: 1 : 4.29
2nd gear: 1 : 2.5, 71% increase
3rd gear: 1 : 1.67, 50% increase
4th gear: 1 : 1.3, 28% increase
5th gear: 1 : 1, 30% increase
6th gear: 1 : 0.8, 25% increase
Reverse: 1 : -3.93
The OpenSCAD file is included and is highly parametric in case you'd like to play with different gear ratios. If you select a different number of teeth, it will print out the resulting gear ratios at the beginning of the output. I also used Matlab to investigate more thoroughly how the gear sizes affected the various ratios. I used transmission.m as an aid in optimizing the ratios to be somewhat evenly spaced.
This was all printed in PLA at 120 mm/s on a Replicator 1 with Sailfish firmware, default layer height (0.27mm). Everything came out perfectly on the first print. I swear, complex models don't have to be difficult, and who needs glue when you can print snap-fits?