|Jon Lawes||09/07/2018 18:45:53|
100 forum posts
Coming along nicely!
|Ron Laden||11/07/2018 14:22:30|
|178 forum posts|
Good News/Bad News
The good news: The drive is all fitted and works very well. I was aiming for 632 rpm at the wheel for a top speed of 6 mph. On the bench the max rpm is 825 but unloaded of course so hopefully about right when loaded.
The bad news: Although the drive works well enough it is noisy and too noisy for my liking. I appreciate that I am standing directly over it and it is in the confines of a small workshop. Maybe loaded outside on a track it wouldnt be so bad or so noticeable. I am wondering if the motor mounting plate is too light, its currently 3mm steel . In hindsight (which is a wonderful thing) I am wondering if it would have been better in 6mm steel or 6mm alu. Plus the central axle bearing is an oilite, would that have been better as a ballrace.
I think I have 3 options: 1) live with it and see how it is on the track, though I am a bit reluctant to do that. 2) Un-press one of the wheels (each axle) and produce a heavier duty version of the motor plate, though this is only based on my assumption that a HD version would improve things. 3) Try and figure a way of adding something or a mod which would reduce the noise.
Will have to give it some thought, though I am pleased with the working of the drive.
|Neil Wyatt||11/07/2018 16:33:54|
13606 forum posts
You may be able to reduce the noise by adjusting the gear clearance.
|2942 forum posts|
Don't panic, I think your test is worst case. The motors are running flat out (unloaded) with nothing to contain the racket . Also your bench could be acting as a sounding board - try putting a bit of carpet underneath the chassis. In any case probably considerably quieter outdoors at service speeds with the motors shielded by bodywork.
Looks like the motor plate bears on the rods. If so may be worth putting some sort of cushion between the rods and motor plates to discourage sound conducting into the frame.
I like the design and build.
|Ron Laden||11/07/2018 21:13:57|
|178 forum posts|
Hi Neil, I ran a folded piece of paper between the gears then slackened and re-tightened the fixing screws and it did help a bit, thanks for that.
Hi Dave, I sat the chassis on a sheet of polystyrene and it did take away some of the noise. There is a 0.5mm gap between the end of the motor plates and the tie bars but I think you are correct in the noise been generated by the motor plates. If I hold onto the plates whilst running the noise does reduce a bit plus the sound changes. Also I think the plates are as you suggest conducting the sound into the frame, if I press each axle box the sound reduces a bit.
Tomorrow I am going to run the drive for a couple of hours just to see if things bed in and if that makes any difference. I will run it outside on the garden table so I can see how it sounds outdoors without me standing over it.
|Jeff Dayman||12/07/2018 12:35:12|
|1201 forum posts|
Hi Ron, You may find that ground level track may absorb quite a lot of noise into the rails, ties/sleepers, and the ballast. However, raised track may amplify noise, as will any hard tabletop. I'm not saying not to implement some of the noise reduction measures others have suggested, that is definitely advisable to do, I'm just suggesting the noise may not be as much of an issue when the engine is running on a track. As you said, the gears may get quieter as they "bed in" but be prepared to adjust the clearance again as the "bedding in" progresses - the gap will get slightly larger as the gears wear. I'd suggest using a few drops of oil on the gears during the "bedding in".
Just asking - are your gears and pinions from the same manufacturer, and are they the same module or DP (that is, are the teeth the same geometry, and intended to run together)? For ideal mesh, the gears and pinions should be same module or DP.
3955 forum posts
is the large gear metal or plastic? I think the commercial ones are usually plastic which will be a little quieter if that is the source of the noise. On the track there will be a lot of other noise from the carriage wheels.
|Ron Laden||12/07/2018 13:53:38|
|178 forum posts|
Thanks, yes the gears are from the same supplier Bearing Boys Ltd (excellent service). Both the pinion and the spur are MOD1 so the mesh should be good. The pinion is steel and the large spur is plastic and I have given them a light coat of lithium based grease. I dont know what the norm is for setting up gears but I used a thin piece of paper which measured 0.004" and placed that between the gears when securing the motor screws. I just wanted to make certain that I didnt have the gears too heavily meshed. The track I will be running on is a raised one so it will be interesting to find how it sounds.
The large gear is plastic and as I mentioned to Jeff I have lightly greased the gears with lithium grease but that sounds as if it is not a good idea if there is a lot of muck that could be picked up. The track I will be running on is raised, I,m guessing that it is probably a bit cleaner than ground level but I dont know. I can make a cover to shield the motors but allow a small gap to allow them some airflow.
|Ron Laden||12/07/2018 19:41:36|
|178 forum posts|
I set the chassis up on the garden table and ran it for a couple of hours this afternoon to bed things in. It certainly didnt seem as noisy outside of the shed out in the open. I also thought it a bit quieter after the couple of hours running but that could have been wishful thinking on my part...lol.
I am going to carry on with it as is and see how it turns out when loaded and running on a track. When I say its noisy, its not horrendous, its just a bit more "clunky sounding" than I expected yet the drive train run smoothly enough.
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