Subject:
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Re: Any Ideas= 8448 and 4 wheel steering?
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Newsgroups:
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lugnet.technic
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Date:
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Wed, 10 Jan 2001 20:18:22 GMT
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Viewed:
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658 times
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In lugnet.technic, blessing wrote:
> I've been thinking about this for about a week and can't come up with
> anything.
> I even looked at the 8880 instructions but I couldn't figure out how to make
> the conversion. Does anyone have any ideas?
Hmm. I'm not a Technic-head, and I haven't actually sat down and played
with the ABS to know how well this would work, but here goes an idea...
In order to look right (and work well, I think), the pivot for the rear
wheels need to be as close to the wheels as possible. So the steering
needs to be mounted on the suspension, not the other way around.[1]
The powerdrive on the 8448 has an outer universal joint on each rear wheel,
to facilitate the suspension. Would it be possible to leverage[2] these
u-joints to allow rear-wheel steering?
Imagine an L-shaped steering arm that rotates horizontally. The point of
rotation is the center of the L. The steering arm is located so the point
of rotation is located directly beneath the existing u-joint, and the axis
of rotation is vertical.
One leg of the steering arm is in line with the outer axle, to which is it
attached (in a manner that allows the axle to rotate, of course).
The steering arm's other leg has a towball pin on the end, so that it can
be attached to the typical steering link (which is attached to the typical
gear rack, etc.).
The main problem[3] with this idea is that the distance from the wheel to
the center of the u-joint will cause the wheel to move noticeably when it
is turned (it will swing around, instead of rotating on it's centerpoint).
It seems like the only way to avoid this problem would be to put a collar
over the one half of the u-joint itself. Too bad I don't know of any LEGO
parts that can accomplish that feat...
Oh, heck. Here's a quick'n'dirty image that hopefully will illustrate what
I'm trying to explain.
<http://www.brickshelf.com/cgi-bin/gallery.cgi?i=26839>
The yellow and black is the L-shaped steering arm. The clear white is the
u-joint and axle. The clear black is the steering link. The steering arm
would rotate around the green axis. The wheel & tire would mount on the
end of the clear white axle.
And yes, I realize the yellow bits don't line up.
--
Steve
1) That's probably an obvious point for many people, but I don't redesign
suspension & steering very often -- I just drive my motorized 8448 around
the floor.
2) You decide if the pun is intended or not.
3) I'm sure there are other problems, I just haven't thought too much about
them.
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Message has 2 Replies:
 | | Re: Any Ideas= 8448 and 4 wheel steering?
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| (...) The problem with using u-joints is that as the angle increases, the output becomes more "jumpy" relative to the input. This is why real cars (and the 8880) use CV joints. With suspension, it's OK, because you can use two u-joints to cancel (...) (23 years ago, 10-Jan-01, to lugnet.technic)
| | | Re: Any Ideas= 8448 and 4 wheel steering?
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| Thank You Steve! it actualy makes sence,I am going to go try this. Gary Steve Bliss <steve.bliss@home.com> wrote in message news:0tap5t49a8ukgha...4ax.com... (...) make (...) wheel, (...) what (...) about (...) (23 years ago, 11-Jan-01, to lugnet.technic)
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Message is in Reply To:
| | Any Ideas= 8448 and 4 wheel steering?
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| Hi, I've been thinking about this for about a week and can't come up with anything. I even looked at the 8880 instructions but I couldn't figure out how to make the conversion. Does anyone have any ideas? Any Help Apreciated! Thanks! Gary (23 years ago, 10-Jan-01, to lugnet.technic)
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