Subject:
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Automatic Transmission
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 30 Nov 1999 21:50:29 GMT
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Viewed:
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573 times
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I have been working on building an automatic transmission for quite some
time but have yet to come up with satisfactory solutions. I am looking
for additional ideas to try. What I consider to be an automatic
transmission in this case is:
[Drive train defaults to a high speed / low torque gear ratio. When
resistance on the gear train causes the motor to stall, the drive shaft
transfers (slips or flips) to another gear train with a lower speed /
higher torque gear ratio. When the resistance is lowered, the drive
shaft reverts back to a higher speed / lower torque gear train.]
One experiment used a worm gear that slid along the drive shaft. The
worm gear first drives the high speed / low torque gear train. The worm
gear is kept from sliding forward by a collar in front of the worm gear
that slides freely on the drive shaft and is connected to rubber bands.
When the resistance to drive the first gear train is greater than the
resistance caused buy the rubber bands, the worm gear slides forward to
engage another gear train. This almost works but I can't keep the worm
gear from binding between the gear trains and causing a stall.
Any ideas or suggestions would be helpful.
Thanks,
Robert Eddings
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Message has 4 Replies:
 | | Re: Automatic Transmission
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| Robert, Some time ago I built something using the gearbox-thingies from the 8880 super car. My vehicle only had two speeds though. But two speeds is quite enough for an electric motor, which operates well over a much wider range of rpm's than an (...) (25 years ago, 30-Nov-99, to lugnet.robotics)
| | | Re: Automatic Transmission
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| From: "Robert Eddings" <webmake@bellsouth.net> (...) If you search both lugnet and rec.toys.lego (via (URL) you should find many discussions of this. As far as I can tell no one has come up with a satisfactory design which is purely mechanical and (...) (25 years ago, 30-Nov-99, to lugnet.robotics)
| | | Re: Automatic Transmission
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| (...) I haven't built a transmission this way, but I have built a number of sliding worm gear mechanisms. I've found that you have to leave enough room between the drive gears so that the worm gear is only in contact with one at a time. (This is (...) (25 years ago, 30-Nov-99, to lugnet.robotics)
| | | Re: Automatic Transmission
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| (...) I remember seeing a type of automatic transmission built many years ago, using Meccano (so something similar should be possible with Technic). It used a swinging 'bob weight' on an arm, driven by an eccentric, and had a second arm coming off (...) (25 years ago, 1-Dec-99, to lugnet.robotics)
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