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jhq,
Interesting design.
Weve been trying the DeWalt 24V motor/gearbox as a servo to control the position of the tail on Terrorhurtz. Thought I might just share some of the observations weve made so far.
see pics at
http://news.terrorhurtz.com/tailservo/http://news.terrorhurtz.com/tailservo/
The weak point of these gearboxes, as you probably know, is the plastic ring gear of the second stage of the gearbox. The first big hit that the tail took and it disintegrated, as expected.
Dustin provide a replacement, which we havent tried yet, but note that the teeth of this replacement part are just watercut - by no means a nicely machined involute spur gear.
In retrospect I probably wouldnt have bothered with the Dustin high-temp brush housing - it does not locate the brushes very well and in the sort of application we are using the motors, I dont think the brushes should get all that hot.
The plastic gearbox housing has oddly shaped ridges on it (for moulding purposes) and would be quite tricky to make a matching mount for, so we cut the front edge of the gearbox back, to expose 12mm of the final ring gear. This has nice regular splines on it for which it is rather easier to make a matching mount.
Interesting idea in your first drawing of driving the rear arms of the flipper. I think this could work quite well, especially if you dropped the rearmost pivot point right down, below the level of the pivot on the chassis. This would get over the inherant poor initial mechanical advantage when driving the front arms and also eliminate the danger of the rear links going over-centre.
good building
John Reid
http://www.teamhurtz.comhttp://www.teamhurtz.com
(Message edited by terrorhurtz on November 18, 2005)
jhq,
Interesting design.
Weve been trying the DeWalt 24V motor/gearbox as a servo to control the position of the tail on Terrorhurtz. Thought I might just share some of the observations weve made so far.
see pics at
http://news.terrorhurtz.com/tailservo/http://news.terrorhurtz.com/tailservo/
The weak point of these gearboxes, as you probably know, is the plastic ring gear of the second stage of the gearbox. The first big hit that the tail took and it disintegrated, as expected.
Dustin provide a replacement, which we havent tried yet, but note that the teeth of this replacement part are just watercut - by no means a nicely machined involute spur gear.
In retrospect I probably wouldnt have bothered with the Dustin high-temp brush housing - it does not locate the brushes very well and in the sort of application we are using the motors, I dont think the brushes should get all that hot.
The plastic gearbox housing has oddly shaped ridges on it (for moulding purposes) and would be quite tricky to make a matching mount for, so we cut the front edge of the gearbox back, to expose 12mm of the final ring gear. This has nice regular splines on it for which it is rather easier to make a matching mount.
Interesting idea in your first drawing of driving the rear arms of the flipper. I think this could work quite well, especially if you dropped the rearmost pivot point right down, below the level of the pivot on the chassis. This would get over the inherant poor initial mechanical advantage when driving the front arms and also eliminate the danger of the rear links going over-centre.
good building
John Reid
http://www.teamhurtz.comhttp://www.teamhurtz.com
(Message edited by terrorhurtz on November 18, 2005)
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