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Unread 27-04-2004, 10:10
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Re: Four Wheel, all steering, non-omniwheel, ONE power/motor source drive

Quote:
Originally Posted by FizMan
I don't know; I see the venture of one power source (while complicated) could potentially be lighter than multiple ones. I mean; even if you have to build a monster gearbox, it'd still only have to be twice the size (maybe less if you're good at compaction) than having two smaller gear boxes. Have to mount 2 motors in a gearbox? Have a gear box X size. Have to mount 4 motors in a gearbox? Have a gear box 2X size. Am I right? So the weight evens out there.

But then you can have a single transmission for the whole thing; 1/2 the pneumatics, 1/2 the mounting, 1/2 the gearing.
With the centralized design you still have the weight of the motors. If you want to add more the a couple you have to have all the gearing to join them. If you want it to shift you can save some weight on only one but you would make up some of that on the amount of chain. Pneumatics don't weigh a lot past the first cylinder. Several of the gearshifting design use 3/4" cyclinder at a very short stroke which are very light.

What you are wanting to do is heavy by nature. With the right design and materials a centralized gearbox may be lighter. This is a tough one to call either way though. The xbox is a fairly good example of this but they said they weighed ninety pounds without shifting. And the only used to motors. More than this would require additional gearing and the gear shifting mechanism would have to be added. In this case you are looking at at around another 20+ pounds which will leave you with a 20 lb arm at most. Weight is a hard constraint to deal with. I think we would see a lot more drivetrains like you envision if we could weight 20 to 30 more pounds.