# Wheel motor - international suppliers



## DougL (Sep 7, 2010)

It seems many on this forum are not too excited about wheel motors, or some think WM are not just ready yet. I have no idea.

As I was researching what seems to be the holy grail of EV the wheel motor, I came across these links.

http://www.alibaba.com/product-gs/235149755/Brushless_Dc_Electric_Car_Hub_Motor.html

http://www.alibaba.com/showroom/car-hub-motor.html

Any experience with international suppliers? Seems that there are a lot of various options and suppliers.

Doug


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## rillip3 (Jun 19, 2009)

No experience with the suppliers. The three major stumbling blocks to hub motors, as I see them:

1) lots of unsprung weight
2) having to control multiple motors with multiple controllers leads to a more complicated setup
3) no gearing means your motors are going to need a very specific torque band to get you to the speeds you want to go. I'd want to see a detailed torque band spec sheet before investing any money


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## DougL (Sep 7, 2010)

rillip3 said:


> No experience with the suppliers. The three major stumbling blocks to hub motors, as I see them:
> 
> 1) lots of unsprung weight
> 2) having to control multiple motors with multiple controllers leads to a more complicated setup
> 3) no gearing means your motors are going to need a very specific torque band to get you to the speeds you want to go. I'd want to see a detailed torque band spec sheet before investing any money




Thanks good input.

1. Weight, doesn't the batteries weight help towards unsprung weight issue?

2. What we are thinking is processor controlled, I come from a robotics background so that is not bad. But the cost for multiple controllers is an issue.

3. don't the motors have built in gearing in the wheels? What you say about torque spec is still true.


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## rillip3 (Jun 19, 2009)

DougL said:


> [/font][/color]
> 
> Thanks good input.
> 
> ...


I'm not sure what you mean about the weight. The batteries are going to way the same, whether the motor is being held up by the suspension or not. 

#2 sounds like it is surmountable for you, good for you on that one. I think the average DIYer would probably be out of their league on that.

The motors usually do have built in gearing, but even then, it's a specific gear. The last one I looked at was a fixed 5:1 I think, which gives you a pretty slow top speed. With a fixed gear, you're going to sacrifice acceleration or top speed, no matter what, but it would really depend on the motor specs as to whether the performance would be acceptable for a given vehicle.


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## Bowser330 (Jun 15, 2008)

rillip3 said:


> No experience with the suppliers. The three major stumbling blocks to hub motors, as I see them:
> 
> 1) lots of unsprung weight
> 2) having to control multiple motors with multiple controllers leads to a more complicated setup
> 3) no gearing means your motors are going to need a very specific torque band to get you to the speeds you want to go. I'd want to see a detailed torque band spec sheet before investing any money


1) Well you don't have to mount the wheel motor inside the wheel do you? Why not mount them next to each other back to back where the front differential would be on an AWD car...you can have half-shafts come from the motors and connect to the front wheels as normal AWD works

2)multiple motors may be able to share controllers, but maybe not, so it may be a bit more complicated in that respect, but less complicated when comes to transmission adapting and shift timing, clutch/ no clutch, Battery pack location, weight of transmission, etc... additionally they can all feed form a central battery source, so its different yes, more complicated than another DIY EV, I don't know 100%.

3) The link below lists the motors as having 380NM but that might mean 2x, since they are trying to sell 2 motors. Still if you were to build an AWD car, 760NM is enough torque..

http://www.alibaba.com/product-free/105699534/e_Car_10_15kw_Hub_Motor.html
http://www.evworld.co.nz/magnetronic-technology/

I emailed the company about the peak power output, hopefully its something like 30kw peak, 10kw cont....in which case with 4 motors AWD, 120kw 760NM, something doesn't seem right, I guess I will just wait for the response...

Keep in mind Ev-propulsion.com has a wheelmotor for a motorcycle available...they could be used on a light car experimentally....


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## DougL (Sep 7, 2010)

rillip3 said:


> I'm not sure what you mean about the weight. The batteries are going to way the same, whether the motor is being held up by the suspension or not.
> 
> #2 sounds like it is surmountable for you, good for you on that one. I think the average DIYer would probably be out of their league on that.
> 
> The motors usually do have built in gearing, but even then, it's a specific gear. The last one I looked at was a fixed 5:1 I think, which gives you a pretty slow top speed. With a fixed gear, you're going to sacrifice acceleration or top speed, no matter what, but it would really depend on the motor specs as to whether the performance would be acceptable for a given vehicle.


What I meant, the batteries weigh a lot thus account a lot to help offset unsprung weight issue. But hey I am not a ME I am an EE programmer.

I too have concerns about being one speed. The ME guys were not as much, we will see. 

My neighbor approached me knowing my work in robotics about making an ATV with wheel motors. He invests in companies and knows how to make money (unlike me). I said I would explore what it would take and put together an engineering team to look at it. It is fun just exploring and we may put together a proto type with him funding it, if nothing else it will be a learning experience.

BTW one year we built a robot with omni wheels, these wheels will drive you forward but also will slip sideways. The robot had four independent wheels and motors each being at 45 degrees to each other. This thing could drive sideways any direction and rotate as you drove forward etc. The math in the controls systems was a challenge. It was beautiful to watch.


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## DougL (Sep 7, 2010)

Bowser330 said:


> 1) Well you don't have to mount the wheel motor inside the wheel do you? Why not mount them next to each other back to back where the front differential would be on an AWD car...you can have half-shafts come from the motors and connect to the front wheels as normal AWD works
> 
> 2)multiple motors may be able to share controllers, but maybe not, so it may be a bit more complicated in that respect, but less complicated when comes to transmission adapting and shift timing, clutch/ no clutch, Battery pack location, weight of transmission, etc... additionally they can all feed form a central battery source, so its different yes, more complicated than another DIY EV, I don't know 100%.
> 
> ...


 Thanks this was helpful, let me know what you find out.

Doug


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## DougL (Sep 7, 2010)

Bowser330 said:


> 1)
> Keep in mind Ev-propulsion.com has a wheelmotor for a motorcycle available...they could be used on a light car experimentally....


I forgot to comment on this. I have seen EV-propulsion, they have been added to options.

Doug


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## major (Apr 4, 2008)

Bowser330 said:


> 1) Well you don't have to mount the wheel motor inside the wheel do you?


I think so; otherwise it is not a wheelmotor. It becomes a motor coupled to the wheel.


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## DougL (Sep 7, 2010)

major said:


> I think so; otherwise it is not a wheelmotor. It becomes a motor coupled to the wheel.


Actually this is one of the options but decreases what we might want to do. Having motor outside wheel does give some advantages.

Doug


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## major (Apr 4, 2008)

DougL said:


> Actually this is one of the options but decreases what we might want to do. Having motor outside wheel does give some advantages.


Yeah, all EVs (road capable 4 wheelers) have the motors outside the wheels. That's why they're not wheelmotors. What's your point?


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## Bowser330 (Jun 15, 2008)

major said:


> Yeah, all EVs (road capable 4 wheelers) have the motors outside the wheels. That's why they're not wheelmotors. What's your point?


Not ALL EVs..... Doesn't the BMW Mini EV use wheel motors? it is plenty road capable and does have 4 wheels.


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## Bowser330 (Jun 15, 2008)

major said:


> I think so; otherwise it is not a wheelmotor. It becomes a motor coupled to the wheel.


What I meant about not having to use the wheel motor inside the wheel is that you benefit from reducing un-spring weight that way while not requiring any gear reduction because the wheel motor is designed to operate at a direct drive rpm range...So I guess I should have said a "motor with a wheel motor rpm range" But thanks for pointing that super important point out.


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## major (Apr 4, 2008)

Bowser330 said:


> Not ALL EVs..... Doesn't the BMW Mini EV use wheel motors?


I don't think so. Last I heard, they used ACP systems.


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## major (Apr 4, 2008)

Bowser330 said:


> But thanks for pointing that super important point out.


Yeah, funny how all in-wheel motors eventually become out-of-wheel motors. Speaking of road capable 4 wheelers. See it time and time again.


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## JRP3 (Mar 7, 2008)

Bowser330 said:


> Not ALL EVs..... Doesn't the BMW Mini EV use wheel motors? it is plenty road capable and does have 4 wheels.


I believe you are thinking of the old PML Flightlink prototype, which never lived up to their hype by the way.
Enertrac has a nice wheel motor for use in motorcycles so it was designed to take the abuse of that application.
http://www.enertrac.net/
Four of them might work in a small car, I know they are using two of them as inboard, (not in wheel), motors for a Miata I believe.




I did see a prototype, Michelin maybe, that actually used a gear reduction unit with an in wheel motor system. However that takes a way some of the simplicity of a direct drive in wheel motor and you may as well use an inboard mounting and save the unsprung weight.


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## Bowser330 (Jun 15, 2008)

JRP3 said:


> I believe you are thinking of the old PML Flightlink prototype, which never lived up to their hype by the way.
> Enertrac has a nice wheel motor for use in motorcycles so it was designed to take the abuse of that application.
> http://www.enertrac.net/
> Four of them might work in a small car, I know they are using two of them as inboard, (not in wheel), motors for a Miata I believe.
> ...


But it did exist prototype or not, it was a fully functioning ev with four wheels using wheel motors.


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## PhaseShift (Oct 12, 2009)

DougL said:


> What I meant, the batteries weigh a lot thus account a lot to help offset unsprung weight issue. But hey I am not a ME I am an EE programmer.


 
Unfortunately, it just does not work out that easily. If your unsprung weight is high, you have to work it out via suspension design and this has practical limits, particularly when you consider the reality of driving on, well, all types of roads from rough to smooth and in all types of conditions, surface friction coefficients etc...

Just step away from the physical mass of the motor and wheel assembly for a moment, but don't forget that putting the mass of the wheel moor out there means beefing up the control arms / strut rods and of course the carrier / spindle assembly if on the front or an IRS setup. All that aside, you are very likely going to end up with an unconventional suspension design; one that either relies on very high spring rates or perhaps a complete change of the chassis that may or may not work well with your battery pack. 

You can go torsion bars, but your chassis has to be designed to resist the flex induced by the fixed end of the bar. You can use a transverse spring assembly (al-a Corvette) which can be very nice, but you are going to be facing some big issues in getting the spring loading to work well with the unsprung load plus you will have to figure out how to get all of that shoehorned into a chassis where you pretty well need a lot of flat space to put a battery pack. 
Maybe you can put the spring / damper set above the load. That would work if you are doing it in a really tall vehicle where your spring fixed end is high enough to give you adequate jounce travel and avoid coil bind- and don't forget, your spring wire diameter is going to be pretty big due to the high rate required by the high unsprung mass, so your coil height in bind is therefore longer and all of this gets even taller. 

If you are driving only on dry pavement that is really smooth, then you probably will not worry so much about unsprung weight until you look at another factor which is the gyroscopic force that you will have in the armature and housing. You are going to feel that as counter input in the steering system, so that too has to be engineered out. Perhaps a mix of high scrub radius and a very heavily restricted feedback loop or some tuning of the spool valves in the steering servo can would help, but it is not going to be easy to overcome it completely. This is particularly true if you want to sell it to the masses who are accustomed to driving a very mature design in their mass produced car / truck / SUV. 

I am not saying this cannot be done. I am saying it is nowhere near as easy as just overloading the sprung weight in hopes that a change in sprung / unsprung ratio will fix the problem. I am sure that with enough time, funding and tools, this can be overcome or at least brought under control to a safe and suitable level. 

If I were challenged to do it, I would look at trying it on a pickup truck or van first. The heavy live rear axle setup and big 'ole diff setup in the center- those are pretty heavy and maybe if you are really savvy, you could work in hub motors on a beam axle setup that would give you RWD. All that work and expense and headache to get you to a point where you are probably not as good as a cheap LSD and a single motor without all the control issues. 

Also, a note about shopping Alibaba.com - note that most of the vendors are not manufacturers, but trading companies. The one highlighted on that search is really into the metal door business. I have lived here in China for more than 10 years and elsewhere in Southeast Asia for several prior to that. My experience is, find the right supplier, not the supplier you can find right now. 

Phase


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## JRP3 (Mar 7, 2008)

Bowser330 said:


> But it did exist prototype or not, it was a fully functioning ev with four wheels using wheel motors.


Just because it moved around doesn't mean it was a fully functioning EV. If it couldn't handle the demands of normal daily use then I don't consider it fully functioning.


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## DougL (Sep 7, 2010)

PhaseShift said:


> I have lived here in China for more than 10 years and elsewhere in Southeast Asia for several prior to that. My experience is, find the right supplier, not the supplier you can find right now.
> 
> Phase


 Thanks a lot of good input.

Doug


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## Bowser330 (Jun 15, 2008)

JRP3 said:


> Just because it moved around doesn't mean it was a fully functioning EV. If it couldn't handle the demands of normal daily use then I don't consider it fully functioning.




http://electric-vehicles-cars-bikes.blogspot.com/2010/05/volvo-recharge-wheel-motor-test-drive.html

There are you happy now, a Wheel Motor EV thats going around a race track, fully functioning enough for you?


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## JRP3 (Mar 7, 2008)

Better, but still, are they robust enough to handle sustained driving, up hills, in rain, snow, salt, potholes, etc? A few seconds of video cruising around a smooth dry track doesn't cut it. For all we know in the next minute they may have started smoking. Notice the comment:


> All previous demonstration videos featuring vehicles powered by PML wheel motors, including the Volvo ReCharge and Ford F-150 and Lightning GT, have been at low speeds suggesting that the cars are either fitted with only one operational wheel motor and/or they are a long way short of their extravagant torque claims.


 Exactly what I've been saying. I'm not saying it's impossible to do, just that we have yet to see it happen under real world conditions and that there are good reasons for that.


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## Bowser330 (Jun 15, 2008)

JRP3 said:


> Better, but still, are they robust enough to handle sustained driving, up hills, in rain, snow, salt, potholes, etc? A few seconds of video cruising around a smooth dry track doesn't cut it. For all we know in the next minute they may have started smoking. Notice the comment:
> Exactly what I've been saying. I'm not saying it's impossible to do, just that we have yet to see it happen under real world conditions and that there are good reasons for that.


"All previous" meaning this latest video shows more than before right ??

A lot of the same type of doubts existed when tesla was making their original claims. And that's fine, I know that I for one am All for the Advancement and diversity of ev technology. It will take time to prove All the naysayers wrong.. There are still some stubborn fools who still doubt the tesla roadster. So it is what it is for now and it will be what it will be in the future.


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## JRP3 (Mar 7, 2008)

Bowser330 said:


> "All previous" meaning this latest video shows more than before right ??


Sure, but as I've pointed out, not much more. I'm sure I could cobble up something that makes a few passes around a track and then falls apart after 10 minutes in real world usage. I'm not saying they don't have something, or that a good wheel motor can't or won't be built, just that we have yet to see it. Because of what a wheel motor has to deal with it will also likely be a more expensive solution to a traditional motor with gear reduction setup and will have limited applications. A very good application of a wheel motor is Mark's motorcycle wheel motor. Bikes are much lighter than cars and have very limited room for batteries so a wheel motor has some real advantages that offset the drawbacks.


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## Bowser330 (Jun 15, 2008)

JRP3 said:


> Sure, but as I've pointed out, not much more. I'm sure I could cobble up something that makes a few passes around a track and then falls apart after 10 minutes in real world usage. I'm not saying they don't have something, or that a good wheel motor can't or won't be built, just that we have yet to see it. Because of what a wheel motor has to deal with it will also likely be a more expensive solution to a traditional motor with gear reduction setup and will have limited applications. A very good application of a wheel motor is Mark's motorcycle wheel motor. Bikes are much lighter than cars and have very limited room for batteries so a wheel motor has some real advantages that offset the drawbacks.


So you're thinking more that the environmental factors and overall use within a moving, dynamic part of the car is a lot to overcome, I can agree with that.

What about the operating rpm range and the efficiencies...you brought up a miata that looks to be using two motorcycle wheelmotors internally mounted..seems like thats sort of a best of both application of that type of motor, no transmission needed and less factors that the motors will have to deal with.

Ive seen a few videos of Mark's wheel motor in the motorcycle and it looked like it had a pretty good pick-up and go...but the torque to move a car is another story, as previously mentioned....


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## JRP3 (Mar 7, 2008)

Right, internal mounting takes away some of the physical stresses on the motor but direct connection to the wheel leaves you with lower RPM, higher amp draw, and possible cooling issues. If the motor can run within design parameters then those issues are less of a problem. You save some efficiency by not having any gear losses and the extra weight of a differential or gearbox but you lose some efficiency with higher current at low RPM's. I'm not sure how the numbers would actually play out.


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## major (Apr 4, 2008)

JRP3 said:


> Right, internal mounting ......


Then it is no longer a wheel motor. 



> The *wheel hub motor* (also called *wheel motor*, *wheel hub drive*, *hub motor* or *in-wheel motor*) is an electric motor that is incorporated into a hub of a wheel and drives it directly.


From http://en.wikipedia.org/wiki/Wheel_hub_motor 

Also, it was invented in 1884. That is 126 years ago. And how many are on the road today (road capable 4 wheelers)? Zero. Tell you anything?

The wheel motor is a product everyone wants, but doesn't exist. 

And once you remotely locate the motor from the wheel, it is the same old same old as we have all been doing. Yeah, you can choose where to mount the motor, choose the ratio between the motor and wheel, and choose to use a single motor or multiple motors, or even choose to use variable ratios (shifting transmission). But it is not a wheel motor any longer.

Regards,

major


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## Automcdonough (Sep 1, 2010)

The added controller complexity is offset by the awesome gain in proportional traction control and torque steering. 4 motors would be awesome.

The traditional hub motors I've seen that look like drum brakes seem like they are only going half-way. High torque is about leverage, better to use the wheel itself as the rotor to get maximum diameter/leverage of the fields. It would have a big ring for a stator that is hollow to leave room for traditional mechanical brakes. This also is adding a lot less metal/weight the solid core approach.. but this opens the door to some other disadvantages like having to unhook wires just to pop the wheel off and rotate the tires. water/dust proofing might be difficult for either type. Also I don't think the windings and magnetics are up to the vibration/stresses that a wheel sees when you fly over some potholes or railroad tracks. There's only so much you can do to protect things, and even tires+wheels get messed up from this stuff.

I've changed enough bent wheels and worn wheel bearings to avoid either on that principle alone. Half those kids that change tires are also not ones I'd want bouncing my motor around on that machine. 
What I had envisioned was the half-shafts disappearing behind a rubber/plastic shield that would keep the motors dry even when driving through 2ft of water, and isolated from the disc brake's heat. There's really no reason to avoid halfshafts, all of that unsprung weight is offloaded to the body where it because just normal weight. No flexing power wires, etc.


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## JRP3 (Mar 7, 2008)

Automcdonough said:


> The added controller complexity is offset by the awesome gain in proportional traction control and torque steering. 4 motors would be awesome.


Can't think of the last time I needed any of that, I seem to be able to steer quite easily. Sure it might be fun to have but it's not worth the added cost and complexity.
railroad tracks. There's only so much you can do to protect things, and even tires+wheels get messed up from this stuff.


> There's really no reason to avoid halfshafts, all of that unsprung weight is offloaded to the body where it because just normal weight. No flexing power wires, etc.


And that's not a wheel motor.


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## Automcdonough (Sep 1, 2010)

JRP3 said:


> Can't think of the last time I needed any of that, I seem to be able to steer quite easily. Sure it might be fun to have but it's not worth the added cost and complexity.


because this lets you dump the power steering


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## JRP3 (Mar 7, 2008)

My Fiero doesn't use power steering


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