apemax Posted January 10, 2011 Posted January 10, 2011 (edited) I'm currently building a Power Functions vehicle (not sure what it's going to be yet) but when i drive it forwards or backwards it sort of jumps forwards, like it's stutering or something. i've tried everything that i can think of but nothing seems to be working. does anyone have any idea's? the input axle is the yellow one and the output axle is the red one. Edited January 10, 2011 by apemax Quote
TechnicJuan Posted January 10, 2011 Posted January 10, 2011 Since you're not using a differential box, I would suggest using something like THIS because more than likely you have a bevel gear slipping. Quote
freakwave Posted January 10, 2011 Posted January 10, 2011 Since you're not using a differential box, I would suggest using something like THIS because more than likely you have a bevel gear slipping. I see that you are using a PF-XL for the drive. If you are using the on/off remote this will indeed be quite jerky and produce also a lot of stress in the involved parts and slipping of these bevel-gears as the motor is quite really strong. As a remote I would recommend to use the 8879 remote With it you can more or less smoothly accelarate/decelerate. I had the same issue with my snowgroomer and it took me more than one season of snow to make it properly snow-worthy to really do grooming and not be there for just going straight fW Quote
Zerobricks Posted January 10, 2011 Posted January 10, 2011 Bad, bad gearing.... You should have 1:1 gearing from Xl motor to the U joint and the final gear ratio should be on axle. This way you wont damage the u joint and the suspesnion wont make the truck tilt. Quote
apemax Posted January 10, 2011 Author Posted January 10, 2011 Since you're not using a differential box, I would suggest using something like THIS because more than likely you have a bevel gear slipping. I never noticed the bevel gears slipping. there wasn't any clicking like when gears are slipping. I was using Knob Wheels before but i replaced them with bevel gears to see if that made any diffrence but they didn't. thanks. I see that you are using a PF-XL for the drive. If you are using the on/off remote this will indeed be quite jerky and produce also a lot of stress in the involved parts and slipping of these bevel-gears as the motor is quite really strong. As a remote I would recommend to use the 8879 remote With it you can more or less smoothly accelarate/decelerate. I had the same issue with my snowgroomer and it took me more than one season of snow to make it properly snow-worthy to really do grooming and not be there for just going straight fW Like i said i never noticed the bevel gears slipping. yeah i'll probably get one of those at some point. thanks. Bad, bad gearing.... You should have 1:1 gearing from Xl motor to the U joint and the final gear ratio should be on axle. This way you wont damage the u joint and the suspesnion wont make the truck tilt. ahh... i'll put the gears after the U joint then. Quote
allanp Posted January 10, 2011 Posted January 10, 2011 Zblj is right. Putting the gearing in the axle will also put less strain on the drive shaft. Too much tourque will cause it to twist and store energy. When the drive shaft springs back (releasing the stored energy) you get that jerky movement. I still say they should remove the gearing down from the motors! Quote
eMHa Posted January 10, 2011 Posted January 10, 2011 Additionally what allanp said, I would say a long axle can twist a lot. The longer a axle, the more twist. In some situation the force of the twist will turn the axle. So you get this "jumping". My advise is to put the motor as near as possible to the wheels, with sorter axles. I also recommend watching the "Trial truck tip" from Zblj, like http://www.eurobricks.com/forum/index.php?showtopic=45639&view=findpost&p=797980 they are very good Quote
apemax Posted January 11, 2011 Author Posted January 11, 2011 Ok so i put all the gearing down after the U joint and changed the bevel gears back to the knob gears but it still does it. The motor is still in the same place but with 3 16T gears going from the motor to the drive shaft. I'll try it this way with bevel gears and see if that makes any difference. Additionally what allanp said, I would say a long axle can twist a lot. The longer a axle, the more twist. In some situation the force of the twist will turn the axle. So you get this "jumping". My advise is to put the motor as near as possible to the wheels, with sorter axles. I also recommend watching the "Trial truck tip" from Zblj, like http://www.eurobricks.com/forum/index.php?showtopic=45639&view=findpost&p=797980 they are very good Ok i'll watch that when i get time. thanks. Quote
rgbrown Posted January 12, 2011 Posted January 12, 2011 Ok so i put all the gearing down after the U joint and changed the bevel gears back to the knob gears but it still does it. The motor is still in the same place but with 3 16T gears going from the motor to the drive shaft. I'll try it this way with bevel gears and see if that makes any difference. Does everything spin freely when you disconnect the motor? Quote
apemax Posted January 12, 2011 Author Posted January 12, 2011 (edited) Does everything spin freely when you disconnect the motor? Yeah everything spins freely. I put a M motor on there just to see what it did and it didn't do it as bad but still did it a bit. I'll take away some of the gearing down to see if that makes any difference. any more idea's? Edited January 12, 2011 by apemax Quote
DLuders Posted January 12, 2011 Posted January 12, 2011 @ Apemax: Could you post new pictures of your new gear configurations? The original pictures do not show the current situation, so it's hard to diagnose the current problem with words alone.... Quote
rgbrown Posted January 12, 2011 Posted January 12, 2011 (edited) @ Apemax: Could you post new pictures of your new gear configurations? The original pictures do not show the current situation, so it's hard to diagnose the current problem with words alone.... Agree, and a video would be even better if you could Edited January 12, 2011 by rgbrown Quote
apemax Posted January 13, 2011 Author Posted January 13, 2011 (edited) Ok here's some pictures of it how it is now. I might be able to get a video of it. The red axle is the input one and the yellow is the output axle. then it connects to the U joint and to the other gears in the other pictures. Edit: ok here's a video of it. Edited January 14, 2011 by apemax Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.