Would a small hub motor work with this ?

[Yoma]

Hi,

I just joined the forum so my apologises if I've meant to give a formal introduction.

Any way, I've been trying to explore sources for a possible idea I had to convert my mobility device, called a knee walker http://www.phc-online.com/Knee_Walker_p/neebop-785.htm ,  into low powered electrically assisted one that I could use ( I guess like a pedelec ) so that I had the option of freewheeling it , or using the motor to help on rougher terrain / hills.

The wheel itself roughly 7.5 " in diameter just so you an idea , but there is no axle I can see - rather the bolt that just holds the wheel in , which you can see in the pics below.

http://www.flickr.com/photos/28633046@N02/

Someone suggested I could adapt the 6" inch direct drive using plate / bracket.

If any one has any ideas or suggestions about that then , or any other way  I could possibly motorise this wee mobility aid ( I might be on it the rest of my life ) id really appreciate it.

thanks.

yoma

[Bikemad]

Hi Yoma andto the forum.

You certainly do have an unusual request, but unfortunately I'm not so sure that a simple solution exists.
Most of the smaller wheelmotors contain built in gears to increase the torque from the motor, including the 6" motor you have already mentioned:

I'm assuming these motors are intended primarily for wheelchair use and are probably designed to drive in either direction, and therefore would not have the ability to freewheel. Without some form of freewheel, it would be very difficult to use the walker manually without power.

However, GM do sell a mini geared brushless hub motor which does contain an internal freewheel device. Although it is designed to be built into a larger wheel, it might be possible to get a small diameter tyre to fit directly to this hub:
      
Looking at the 3D Solidworks drawings, I estimate this hub to have a flange diameter of approx 135mm, and the area between the flanges appears to be about 47mm wide and 114mm diameter.
It might just be possible to stretch a single 7x1 3/4" solid tyre, or even squeeze two 4 x 1" solid tyres side by side directly onto the hub, but that's just a wild guess.

Provided that a tyre (or tyres) can be made to fit the minihub, fitting the hub to the walker instead of the two rear wheels should be possible, but unfortunately it will not be straightforward, as some form of mechanical brake will still need to be fitted, along with a battery, speed controller, wiring and a throttle.

If you do not have the skills and facilities to fabricate the required fittings yourself, then you would obviously need to find someone who is both prepared and capable of doing the work for you, but it probably won't be cheap.

I hope you find this information useful, and I wish you luck with your conversion, and if you are able to to adapt it, I would love to see some pictures of the completed conversion.

Alan
 

[Yoma]

Hi Alan,

I just sent 2 email last night to golden motors ( both in the US / Asia where they sell the kits ) so I will see what happens .

I just assumed the the guy in the uk ( who also deals with Alien ) would be less likely to know as he doesnt sell the kits .

Im assuming there must be some size of wheel that fit on these minihub motors i.e. what size of wheel are they used for normally ?

If gm don't respond ( has anyone ever had a response / why bother having an email ?? )  then maybe there are other mini hub motors by other manufacturers who do.

Thanks any way , for all that helpful information .


yoma

[Bikemad]

Yoma,

I'm not sure what the smallest rim size is that can be fitted to the minihub, they are normally used for 20 to 28" wheels, but I would assume 16" should be possible, although 16" is still much too large for your intended use.

I suggest you email Vincent Ross (sales@davincimobility.co.uk) or if you're in the UK, give him a call on 01515 481999.
Da Vinci Mobility are GM dealers who specialise in custom built wheelchairs and they may be able to offer some useful advice or suggest a better solution for your particular needs.

Da Vinci Mobility
6-8 Carraway Road
Gillmoss industrial estate, Liverpool
L11 0EE
UNITED KINGDOM
Tel: +44 1515481999
Fax: +44 1515480333
www.davincimobility.co.uk

Let us know how you get on.

Alan
 

[Yoma]

Yoma,

I'm not sure what the smallest rim size is that can be fitted to the minihub, they are normally used for 20 to 28" wheels, but I would assume 16" should be possible, although 16" is still much too large for your intended use.

I suggest you email Vincent Ross (sales@davincimobility.co.uk) or if you're in the UK, give him a call on 01515 481999.
Da Vinci Mobility are GM dealers who specialise in custom built wheelchairs and they may be able to offer some useful advice or suggest a better solution for your particular needs.

Da Vinci Mobility
6-8 Carraway Road
Gillmoss industrial estate, Liverpool
L11 0EE
UNITED KINGDOM
Tel: +44 1515481999
Fax: +44 1515480333
www.davincimobility.co.uk

Let us know how you get on.

Alan
 

Hi,

I recollect that name form somewhere , no doubt while looking for solutions when stuck on my mobility scooter.

Perhaps, as you say, he can give me some other ideas , as Gm motors have not , and probably wont, reply .

thanks once again,

yoma

PS. Have you ever heard of the following company ?
http://www.elebike.com.tw/pro.htm

[Yoma]

Yoma,

I'm not sure what the smallest rim size is that can be fitted to the minihub, they are normally used for 20 to 28" wheels, but I would assume 16" should be possible, although 16" is still much too large for your intended use.

I suggest you email Vincent Ross (sales@davincimobility.co.uk) or if you're in the UK, give him a call on 01515 481999.
Da Vinci Mobility are GM dealers who specialise in custom built wheelchairs and they may be able to offer some useful advice or suggest a better solution for your particular needs.

Da Vinci Mobility
6-8 Carraway Road
Gillmoss industrial estate, Liverpool
L11 0EE
UNITED KINGDOM
Tel: +44 1515481999
Fax: +44 1515480333
www.davincimobility.co.uk

Let us know how you get on.

Alan
 

Dave ,

I took some measurements and the bore on my current wheels are smaller than I thought ( 7mm ) as opposed to the 8 at greentyres .

What I was going to ask then , was whether you think something like  a hub ring would be ok to offset this difference if I was to use the mini hub motor i.e. because from what I see of videos of it , it seems to wobble a lot .

Im not sure about the bearings either in this wheel i.e. whether thier hybrid plain shield etc etc which Im guessing will be important too If I do stick a motor on there .

thanks

yoma

[Yoma]

Do you mind me asking what sort of bore size this fits ?

I cant see any reference anywhere and cant seem to get working version of edrawing to see, and of course Gm wont reply 

thanks

yoma

[GM Canada]

Do you mind me asking what sort of bore size this fits ?

I cant see any reference anywhere and cant seem to get working version of edrawing to see, and of course Gm wont reply 

thanks

yoma

What measurments are you looking for. I have rimmed mini motors in various sizes here and can measure what you like. By bore size do you mean the axle thickness?

Sorry I'm not technical person, but I like to help if I can.

Gary

[Yoma]

Do you mind me asking what sort of bore size this fits ?

I cant see any reference anywhere and cant seem to get working version of edrawing to see, and of course Gm wont reply 

thanks

yoma

What measurments are you looking for. I have rimmed mini motors in various sizes here and can measure what you like. By bore size do you mean the axle thickness?

Sorry I'm not technical person, but I like to help if I can.

Gary

Hey Gary,

Yes,  I mean axle thickness or diameter ( basically how wide the centeral hole of the wheel / hub is )

You can see my bearing if you go below
 http://www.mcmaster.com/#ball-and-roller-bearings/=9i3dx1

and do a search for part no 5972K286   

the inside diameter or bore is 10 mm   
outside diamteter is 22
and the width 6 mm

I basically need to know then if the diameter of the axel for the mini hun motor will fit 10 mm

but anything else too like the length of the axle would be useful too.

thanks

yoma

[GM Canada]

Hi Yoma

I am away visiting relatives for a few days. I will try to get back to you by monday with those measurments.

Gary

[Yoma]

Hi Yoma

I am away visiting relatives for a few days. I will try to get back to you by monday with those measurments.

Gary

Thank Gary,

Just whenever you get the chance .

yoma

[Bikemad]

Yes,  I mean axle thickness or diameter ( basically how wide the centeral hole of the wheel / hub is )

I basically need to know then if the diameter of the axel for the mini hun motor will fit 10 mm

but anything else too like the length of the axle would be useful too.

Yoma, the minimotors do not have a bolt going through a hole in the centre like your existing wheels, instead they have a fixed axle which must be securely attached at each end to transmit the torque from the motor (see the attachments below for more details of the front minimotor).

The axles on these motors have a 14mm thread with 10mm flats machined into it.

Alan
 

[Yoma]

Yes,  i mean axle thickness or diameter ( basically how wide the centeral hole of the wheel / hub is )

I basically need to know then if the diameter of the axel for the mini hun motor will fit 10 mm

but anything else too like the length of the axle would be useful too.

Yoma, the minimotors do not have a bolt going through a hole in the centre like your existing wheels, instead they have a fixed axle which must be securely attached at each end to transmit the torque from the motor (see the attachments below for more details of the front minimotor).

The axles on these motors have a 14mm thread with 10mm flats machined into it.

Alan
 

Alan,

What about just screwing the whole hub motor in with the axel then , or is this just a stupid / bad idea ?


yoma

[Bikemad]

Only attaching the motor by just one end of the axle would not be a good idea as it would exert considerable bending forces upon the hollow end of the axle where the wires pass through. I would definitely not recommend mounting it like that, as it is just asking for trouble.

Alan
 

[Yoma]

Only attaching the motor by just one end of the axle would not be a good idea as it would exert considerable bending forces upon the hollow end of the axle where the wires pass through. I would definitely not recommend mounting it like that, as it is just asking for trouble.

Alan
 

What about having another hun on the other side , and possibly finding an option that would lessen the power output then ?

I asked about the Bafang Fun motor and got told similiar sort of negtive things, which makes sense but the problem is there is no axle thread that runs from each side - unless I could create one smaller than the the 10mm to pass through the fitting thats enclose in there ( perhaps not a good idea either) or just cut open the area with pipe cutter .

The problem with that idea is the rear had no space in the middle thank to the 2 crossbars that meet
i.e. im lucky if theres eve an inch there .

The front has maybe 3- 3.5 " at glance of clearance - but somehow that would not look right / perhaps draw attention to myself which would not be good i.e. I want this to look a legit mobility device not some crazy mod .

I think there are some other knee walkers thats have clearance at that back / middle where I could stick a motor , though I would still need to somehow cut in there and possibly removed that screw fitting ( not sure the technical name ) thats bit like one of those screw- in light bulbs .

Its pity there wasnt cheaper , less powered option to just fit on the wheels , as Bafang and Gm certainly don't offer it.