Converting a hubmotor to a middrivemotor

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.

bØb
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Re: Converting a hubmotor to a middrivemotor

Post by bØb » Wed Dec 19, 2012 9:11 pm

OK. Under the hub (that is probably part of the sun gear) is that the outer race of a ball bearing I see in the picture? If so, I think the axle may push out of the stator holder from the opposite side.

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Re: Converting a hubmotor to a middrivemotor

Post by StudEbiker » Wed Dec 19, 2012 9:28 pm

I'm not quite getting what you're seeing. I don't see any outer races. There is a small gap between the ID of the sun gear and the OD of the axle, but I don't see anything that looks like it's part of a bearing. Obviously since the sun gear is spinning there's a bearing in there somewhere though. Here is a better picture.

008.JPG
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Re: Converting a hubmotor to a middrivemotor

Post by bØb » Wed Dec 19, 2012 10:42 pm

There has to be a bearing with it's outer race attached to the hub you pulled the stator off of. The hub and the sun gear are probably made from the same piece. The inner race of the bearing is on the axle. The stator carrier (aluminum piece with holes in it) is keyed and pressed onto the axle. If you press the axle from the side that you can see the key (the opposite side in your last picture) and support the stator carrier on the side shown in your last picture, it should come out of the stator carrier and have the bearing and hub still on the axle. There is also the possibility that the bearing inner race is around a tube attached to the hub and sun gear and the outer race is supported by the stator carrier. If it is you would press from the side in you picture and the axle would come out, leaving the sun gear, hub and stator carrier together. This is the best I can deduce from the pictures thus far. I only have experience disassembling a MAC. I think the motor crossbreak is using is more like yours than a MAC. After proof reading this I think the second method might be the best to try first if you don't get any information from crossbreak. You may be able to move the axle with a soft face mallet,just be sure to support only the stator carrier.

I think it is worth a try to press the rotor back on the hub. Just get it straight and use Red Locktite on it. I would help if you could put it in a Lathe or between V-blocks to track it straight.

The picture that fecther posted tonight with the note about the circlip is of my MAC motor. The bearing is between the sun gear built on the hollow tube and the stator carrier. You take the clip off and the only thing holding the stator is the magnets. The sungear/hub/tube is a slip fit to the bearing inner race. If you connected the wires , controller, battery and held the motor up by the hollow shaft, you could run it in your hand. This is why I think a MAC may be easier to convert than some others.

In a few days I am going to try to start a topic about MAC motor conversions and try to leave this thread to deal with bafang or similar motors. It is becoming confusing to follow :roll: bØb
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BTW I'm also disappointed in the "Myans Calendar" just "Sloppy Workmanship"

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Re: Converting a hubmotor to a middrivemotor

Post by StudEbiker » Wed Dec 19, 2012 10:51 pm

Okay bob, I got the axle out. From by hitting the axle from the end opposite the sun. Thanks. :) Should the bearing on the sun gear feel completely smooth? This one has noticeable drag and rough spots.

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Re: Converting a hubmotor to a middrivemotor

Post by bØb » Wed Dec 19, 2012 10:59 pm

It should turn smooth. What kind of bearing is it?

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Re: Converting a hubmotor to a middrivemotor

Post by StudEbiker » Thu Dec 20, 2012 1:45 am

It looks like a sealed bearing.

011.JPG
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Re: Converting a hubmotor to a middrivemotor

Post by crossbreak » Thu Dec 20, 2012 4:53 am

hey StudEbiker,

hope your magnets took no damage :? Maybe the pics on page 8 shows the problem? Also this page here: http://www.ebikessf.com/disassembled-bmc-motor

Maybe one should not separate rotor and axle on a BMC when doing the conversion. I ask myself how ebikessf did. I have a guess, look at the pic below. This does not seem to be as simple as I thought.

Just for our interest: Now that you got the axle out already, can you pull off the bearing and hub? There can not be any hidden snap rings anymore I guess.

My bafangs seem to be different from both BMC and MAC :? if I remove the two outer snap rings, there is just the magnet force which holds the rotor on the axle. But you can not push out the axle if the sun gear and the rotor are not pulled off first, since there is a hidden snap ring between sungear and rotor. The sungear can be simply pulled off by hand.

All the best!
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Re: Converting a hubmotor to a middrivemotor

Post by StudEbiker » Thu Dec 20, 2012 11:42 am

I think the magnets are fine.

Yeah, it was that exact picture on ebikessf that I couldn't quite figure out what they were doing. I guess you have to support the stator through the openings in the rotor somehow and then pound out the axle from the side opposite the sun gear. So yeah, the rotor and axle will not separate on a conversion of an Ezee motor.

There is another snap ring on the back side of the hub that you can see in my last picture. I'm not sure what would happen if I take it out. I have just placed an order with ebikes.ca so I may contact them about getting another bearing for the hub as it seems like this one is not turning as smoothly as it should be and maybe I can find out from them about how to remove the hub from the axle, but as far as this type of conversion goes on an Ezee motor, removing the hub is not something you should normally need to do.

I think it is good that we are getting quite a few different types of motors in this one thread with the same goal in mind. And I like what you have done on page one showing a synopsis of what's been done "so far" as each of these motors seem to have slightly different designs, I think it's good to have them all in one place for anyone that is thinking about doing this in the future.

I am still very excited about this type of conversion and I appreciate your work developing this new type of drive! :D

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Re: Converting a hubmotor to a middrivemotor

Post by bØb » Thu Dec 20, 2012 11:45 am

StudEbiker wrote:It looks like a sealed bearing.

011.JPG


StudEbiker,

Sorry I missed this post last night. I checked several times for a new post and then retired to bed.

At this point, can you remove the key from the shaft, smooth any burrs and push the shaft from the bearing (left to right in .011.jpg)?
Has that snap ring in 001.jpg been rubbing on something?
Does the bearing feel dry when you rotate it? Heat from the stator could cook the lube out of the bearing. Especially if the motor had been overheated.
This is the "Achilles Heel" of geared hub motors: getting the heat out of the stator. I'm sure that not news to anyone though :|

bØb
I'm not building an Electric Bicycle because I want to save the World. I just don't like to pedal!
BTW I'm also disappointed in the "Myans Calendar" just "Sloppy Workmanship"

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Re: Converting a hubmotor to a middrivemotor

Post by StudEbiker » Thu Dec 20, 2012 11:57 am

bØb wrote:
StudEbiker,

Sorry I missed this post last night. I checked several times for a new post and then retired to bed.

At this point, can you remove the key from the shaft, smooth any burrs and push the shaft from the bearing (left to right in .011.jpg)?
Has that snap ring in 001.jpg been rubbing on something?
Does the bearing feel dry when you rotate it? Heat from the stator could cook the lube out of the bearing. Especially if the motor had been overheated.
This is the "Achilles Heel" of geared hub motors: getting the heat out of the stator. I'm sure that not news to anyone though :|

bØb


Not a problem. I had to go to work last night for awhile so I couldn't respond until pretty late.

Yeah, the bearing feels pretty dry. The previous owner said he was running this around 1k watts, so that's definitely a possibility.

I don't think it has been rubbing on anything, but I see what you are talking about. One thing is, I think when I was trying to pull the rotor off, I think this hub may have moved a little. When I got the rotor off, I could see that one end of the ring was out of it's groove. I tried pushing the hub back on the axle a little and that seemed to smooth out the bearing a little, but it still doesn't feel good. I have just sent an e-mail to ebikes.ca about getting a replacement.

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Re: Converting a hubmotor to a middrivemotor

Post by bØb » Thu Dec 20, 2012 12:31 pm

I do have to say that a MAC appears to be a lot easier to disassemble and convert. I can disassemble a MAC with A #2 Phillips screwdriver, a pair of snap ring pliers, a pair of end nippers to remove keys from axle (you could use a blade screwdriver and a hammer though), a pair of diagonal cutters to cut the wires and a small soft faced hammer. Though a vise is handy to hold things, I could hold it in my lap :lol: There is nothing hard or tricky about a MAC and they show a lot of thought in design and assembly. I AM IMPRESSED! I DON'T WORK FOR THEM! And I got mine "the old fashioned way", I paid real money for it!

bØb
I'm not building an Electric Bicycle because I want to save the World. I just don't like to pedal!
BTW I'm also disappointed in the "Myans Calendar" just "Sloppy Workmanship"

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Re: Converting a hubmotor to a middrivemotor

Post by StudEbiker » Thu Dec 20, 2012 3:44 pm

bØb wrote:I do have to say that a MAC appears to be a lot easier to disassemble and convert. I can disassemble a MAC with A #2 Phillips screwdriver, a pair of snap ring pliers, a pair of end nippers to remove keys from axle (you could use a blade screwdriver and a hammer though), a pair of diagonal cutters to cut the wires and a small soft faced hammer. Though a vise is handy to hold things, I could hold it in my lap :lol: There is nothing hard or tricky about a MAC and they show a lot of thought in design and assembly. I AM IMPRESSED! I DON'T WORK FOR THEM! And I got mine "the old fashioned way", I paid real money for it!

bØb


Well, now that I know how the Ezee comes apart, those are the same tools you need to take this motor down as well. There's was no need to take the planets off which was the only thing you need the puller for. I think the Ezee is almost exactly the same as a MAC/BMC.

Edit: I just tapped the hub on a little further onto the shaft and now it's turning smooth again. Now to just get the rotor back on the hub and I should be all good again. :D

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Re: Converting a hubmotor to a middrivemotor

Post by bØb » Thu Dec 20, 2012 4:33 pm

StudEbiker,

I'm glad it looks like your hub has survived. I know it can be disappointing to break something trying to make it better :(

bØb
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BTW I'm also disappointed in the "Myans Calendar" just "Sloppy Workmanship"

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Re: Converting a hubmotor to a middrivemotor

Post by mr.electric » Thu Dec 20, 2012 4:37 pm

I made a custom Mac /bmc puller after wasting a few hours gluing a magnet back down on my first bmc disassembly and repair. I have used it numerous times now.
ImageUploadedByTapatalk1356039089.109383.jpg
ImageUploadedByTapatalk1356039089.109383.jpg (100.65 KiB) Viewed 1148 times

It is made from a cheap steering wheel puller. The ends have been reshaped on a grinder.
ImageUploadedByTapatalk1356039361.694285.jpg
ImageUploadedByTapatalk1356039361.694285.jpg (110.57 KiB) Viewed 1148 times

Fits in the holes in the stator like so.
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Re: Converting a hubmotor to a middrivemotor

Post by mr.electric » Thu Dec 20, 2012 11:02 pm

ImageUploadedByTapatalk1356062450.944418.jpg
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Getting ready to spin this motor with a wheel connected.
-Fat Sand Bike with 9c and 29ah pack

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Re: Converting a hubmotor to a middrivemotor

Post by StudEbiker » Thu Dec 20, 2012 11:45 pm

Wow, that looks great. 8)

Do you have that FW adapter attached to the axle yet, or is it just on there for the picture?

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Re: Converting a hubmotor to a middrivemotor

Post by mr.electric » Fri Dec 21, 2012 9:15 am

The freewheel adapter is all set up for the rear wheel. I changed it a bit since the pic and installed a plate sprocket instead of a freewheel for the motor to wheel drive in order to get a perfect chainline.
-Fat Sand Bike with 9c and 29ah pack

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Re: Converting a hubmotor to a middrivemotor

Post by bØb » Fri Dec 21, 2012 10:19 am

That is one slick looking mount :D

How about a wide shot of the frame you have it in :shock:

bØb
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Re: Converting a hubmotor to a middrivemotor

Post by crossbreak » Fri Dec 21, 2012 1:02 pm

Hey mr.electric,
looks like a tough mount. Where did you get the frame, is it self made? Which bat voltage, turn count of your MAC and gear ratio to the cranks do you use?

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Re: Converting a hubmotor to a middrivemotor

Post by fechter » Fri Dec 21, 2012 1:11 pm

Looks great!
Are you using the freewheel threads on the motor housing to hold it on to the bracket?
Is there something holding the other side?

If the motor is running but you're not pedaling, is the freewheel ratchet sound going to be annoying?
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Re: Converting a hubmotor to a middrivemotor

Post by mr.electric » Fri Dec 21, 2012 3:51 pm

ImageUploadedByTapatalk1356122616.625713.jpg
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I bought the frame from Green Machine here on ES. It has tabs to mount a battery box in the middle of the frame and comes with the box. I also like the long chainstays for the purpose of mid mounting the motor. Green Machine also sold me the bracket which is really nice. It is adjustable , strong and light. The entire frameset wheels and motor bracket came in one box. I still have to finish assembly. More pics to come during the weekend.
Fechter,
I can buy a "double freewheel " but I will test the bike with the jack shaft configuration first. The cranks will be switched but that should be ok. I wonder if the pedals will unscrew themselves being flopped to the opposite side? I could just tighten the hell out of them and call it a day.
I will probably run a derailleur in the back and a 9 speed with a rapid fire type lever.
Last edited by mr.electric on Fri Dec 21, 2012 6:09 pm, edited 1 time in total.
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Re: Converting a hubmotor to a middrivemotor

Post by spinningmagnets » Fri Dec 21, 2012 4:58 pm

IMHO that is the best place for a non-hub motor. It can be configured to drive the BB, or it can power the right side or the left side of the rear wheel.

Many builders who start traveling fairly fast have mentioned that a short bike with high power has a tendency to wheelie. Its fun a few times, but after a while it seems many begin expressing a desire to use a frame that is a little longer. If you want to stretch a frame "just a little", then making space between the seat-tube and the rear wheel gets my vote. Plus, it still leaves the frame triangle for the battery pack, if that appeals to you...

edit: here's a pic from July 2010 with a 10-inch diameter pan to show how it was possible:

Image
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Re: Converting a hubmotor to a middrivemotor

Post by Green Machine » Fri Dec 21, 2012 5:01 pm

Here is the same frame set that mr electric is building with a hub motor in the wheel to give you guys an idea what the frame should look like when built up.

The bottom plate behind the seat tube was designed to withstand the torque of a mid drive.

I guess we shall see soon. :)
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Re: Converting a hubmotor to a middrivemotor

Post by teklektik » Fri Dec 21, 2012 5:41 pm

mr.electric wrote:I bought the frame from Extreme Green.

Pretty neat frame. I can't seem to locate a site for them - you you have a link or are they local only?
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