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Showing results for tags 'limited slip diff'.
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Here's a creation I put together in a couple of evenings after Wall-E to enter in a trial contest at a LUG meeting: The contest had a few rules: - Use the 62.4 Lego tires (which do look a little small for the height on this model) - Make it 17-20 studs wide - Use 1 IR reciever - Use 1 or 2 motors for drive - 1 motor for steering Everything else was pretty much free game. It features quite a load of "stolen" ideas: - Zblj's little portal hubs (thanks for that nice idea, though I should brace them more since they can get seperated a little under force as I found out at the trial) - Snipe's limited slip diffs with rubber bands (though obviously more people used this idea, I am not sure who used it "first", I only know I saw Snipe's post first. Either way: thanks) - TLG's 9398 steering setup (which I only made a little smaller) While I know diffs aren't a good idea on trial trucks, I refused to have no diffs in my model. So I looked at other options, came across something called "torsen diffs" but I couldn't fit them in a 20 stud wide vehicle with portal hubs (21 is the best I got). Then I came across this idea for a sort of limited slip diff, which worked pretty well at the trial. You can also see the steering axle has some free play (and 2 bevel gears) so the steering would still work when the suspension is at an angle. On a rare occassion, under force the bevel gears would skip on the gear rack since on the other end are 2 universal joints, so bracing isn't the best at it could be. Also given the fact that due to the suspension the steering axle's range of motion isn't even fully utilized I could have probably braced it in the given space, but I didn't find out until the trial that this actually needed some better bracing Trying to keep the weight low and balanced I learned that a battery loaded AAA battery box is about equal in weight to a XL motor and servo motor. So having the 2 motors on one side and the battery box on the other seemed like a good idea.The XL motor ended up with a gear reduction of 1:7. Which means it certainly isn't the fastest, but it runs up a steep hill until it would simply fall on his back before gears would grind. Gears did grind however at the trial, but that was partially due to lack of skill from the driver and especailly one very annoying (yet awesome, because it proved to be the most challenging) obstacle After I had a functional chassis, I pretty much slammed a body on top of that with a little interior. I didn't have much time left before the meeting to make it really fancy. In hindsight I would have probably made it a little bit lower and cover more of the chassis, but I still think it turned out all right The guy who organized the trial at the meeting said we had to keep a space open on the model for a 2x4 tile. He made these nice 2x4 tiles with a custom print. Of course you would like a video, but at home I don't have much obstacles suited for "trial". However at the meeting, the guy who organized it made a video, but he hasn't released it yet. I hope to see it soon so I can link it here -
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I turned my simple 90° indexer into a light slip clutch and to me it seemed very suitable for application in a limited slip differential. I replaced the angle element with square mid-section with a 2L axle connector so it has 8 preferred positions (45° steps) instead of the 4 in the 90° indexer. I played a little with it and even in a small light-weight push-along car you can sense the straight-line-stability and the clutch actually starts slipping when pushing the car through turns. The white silicon band can be replaced with a red one wrapped around the limiters (2L liftarms) twice to make the clutch tighter. I think this approach gives a very realistic effect, or at least an effect that is realisticly proportional to Lego vehicles, also motorized vehicles. But you will have to find out that for yourself. EDIT: As has been pointed out below this does not really qualify as LSD. The friction clutch is always engaged and for it to be a LSD the clutch should only be engaged when one of the output axles slips. LXF-file here. -
i started a moc of a crawler trial type truck with a lsd (limited slip differential) which receives power from the motor through bevel gears that keep skipping and getting destroyed any help or suggestions would be appreciated i used an old style diff next to a clutch gear so the drive axle has some resistance only problem is the 16 tooth bevels won't mesh correctlly. -
Hello everybody! I'm a newbie here, but Lego Technic was a part of my live many years ago. Recently it turns that that we meet again and I'm ready to discover or invent something new for me. About several months ago I got the well-known 9398 Crawler - amazing flagman model with a lot of pro and cons (I believe that many spears and axes were broken, so I'll skip the long list). The main disadvantage is differentials (also known as diffs) that makes the off-road or crawling ability so close to zero. A common recommendation is to get rid of them by replacing by the knobs. It works, but I faced another issue then: now it can't go on a flat surfaces. Really, now the rear axle tries to pull the vehicle ignoring the forward one and broke the axels or suspension. As solution I remembered the limited slip differential based on the 20-tooth clutch gears: add the one more axle between the left and right wheels that has one (or two if necessary) clutch gear. It allows to have some difference between the wheels rotation angle, but in the same time provides some friction that prevents the free rotation. I remember that I saw it at somebody's MOC, so I will add the credits a bit later. Let me don't bush around and provide the my receipt (sorry for the quality, it was a phone): 1. The additional axle. 9L axle with two 20t gears, normal one and clutch, and connectors. Plus 2L beam to reinforce the connection (you'll see it later). 2. Place where to mount it. You'll need to remove the 11L beam from the steering arms add this assembly. 3. Mounted. 4. Now let's move the 2L red beam to lock the connection. 5. The result! Completely mounted and covered by two 3x5 Bent beams (instead of two 3L beams at the original model). As summary, I have to say that now it works fine everywhere (limited only by Crawler's design) and requires a minor changes for the original model. That's all so far, hope that it still actual since the model is relatively old.