|
Re: Advantage to six wheel drive?
Quote:
-RC |
Re: Advantage to six wheel drive?
Quote:
So, I'll restate my thesis: Live-axle Mass = sprocket, hub(s), shaft, wheel, mounting screws Dead-axle Mass = sprocket, wheel, mounting screws BOTH approaches use at least two bearings... the Live-axle would have at least _two_ friction points at each end of the shaft... and the Dead-axle would also have _two_ friction points built into the center of the wheel from the two separate bearings residing in the center wheel hub-area... The mechanics of the Live-axle setup causes more friction/resistance at the bearings because of the angular pressures caused by the shaft pivoting inside the bearings as the pressures on the attached wheel (at far end of the shaft) change... times that resistance by six wheels... I KNOW these are _minute_ differences (or, are they?)... but, it's fun to think this through... HOW am I doing so far? Not bad for a former insurance-salesman, right? ;-) |
Re: Advantage to six wheel drive?
Quote:
For a dead axle system, your axle is held by two plates, often inches apart, and any tolerance issues will make that shaft crooked and lead to extra friction on whatever is driving it. The double bearing issue you mention for live axle has always been a nonissue for us, our bearing blocks are one piece for the bearings and use the same hole. The load from the cantilever is higher, that is true, but it's still well within the spec of the bearing. We slammed down HARD in 2010 and didn't have a single issue anywhere, and our drive was still nice and low friction at the end of the season. I'd argue that few teams had lower friction drivetrains than us. If anyone wants to see our live axle drivetrain, check out my uploads. Our previous 5 robots are there, all using variations of the same system. |
Re: Advantage to six wheel drive?
Terminology Help needed???
The discussion here live axle vs. dead axle yet both options still powered wheels? I am sure I am wrong but, to me the term dead axle, lead me to believe a non-powered wheel. A simple bolt (axle) through the frame rails, with a wheel. No sprocket, chain or belt. For example the rear wheels on a front drive car are a dead axle. So here in FIRST does live axle = wheel fixed to the axle (power to axle), axle rotates in frame bearings--and dead axle = axle fixed to frame, yet wheel is powered? I guess if that is true, live or dead axles could be, or not be, powered? Thanks Troy |
Re: Advantage to six wheel drive?
With a dead axle, the axle does not rotate. The wheel has bearings in it that ride on the shaft and the drive sprocket is attached to the wheel.
With a live axle, the axle and wheel are connected together. The axle rotates on bearings and the drive sprocket is attached to the axle. With the WCD setup, the wheel is cantilevered. It is very easy to maintain since you don't have to remove the drive sprocket and chain to remove the wheel. |
Re: Advantage to six wheel drive?
Quote:
In a live axle system, the wheel is attached to the axle, and whatever form of power transmission you have is attached to the axle. In a dead axle system, the wheel is attached directly to whatever is powering it, and the axle does not necessarily have to spin with the wheel. Examples of both would be: Live axle http://www.chiefdelphi.com/media/photos/36934 Dead axle (from our 2011 robot)  There is a sprocket bolted directly to the wheel on the other side, and the flat head shoulder bolt does not spin. |
| All times are GMT -5. The time now is 05:23. |
Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi