Hi Bill, Yes, we have used various man lifts for over a decade that utilize the hub motor design. Of course, their to speed is about 3-5 mph! This negates the unsprung weight issue, and the torque to size is pretty handy.
-Tom On Tue, Dec 24, 2013 at 1:38 PM, Bill Dube <[email protected]> wrote: > The supposed space savings is very much in the mind of the executive that > funds a hub wheel endeavor. It turns out not to really save much space, > unfortunately. > > The gear losses are about 7%, give or take, when you use a gear reduction > to centrally mount a small high-speed electric motor. When you use a gear > box, the motor/gearbox combination becomes much smaller and cheaper than > the direct drive hub motor. This is because the torque of the motor is > directly proportional to the size and the cost. Speed (rpm) has little > influence on the cost of a motor. A gearbox thus greatly reduces the cost > and makes the motor/gearbox combination smaller, so there really, in the > end, is not much space saving. > > The trouble is, one cannot completely solve all of the innate problems of > an in-wheel motor in a highway capable vehicle. At least not economically > for most of the problems and for the other problems perhaps not at all. > This is what every major car manufacturer has independently confirmed. > > The very first attempt was by Porshe in the late 1800's. > http://press.porsche.com/news/release.php?id=642 > It was not really highway capable, however, as its top speed was 22 mph. > > I could go on and on. (I have done so before. Look it up in the archives.) > Hub motor vehicle prototypes die the "death of a thousand cuts". It is not > just one problem, but many subtile, very serious, issues. Each takes its > toll to eventually kill the production vehicle. > > I should note that for low speed vehicles and for racing vehicles, hub > motors and individual wheel motors can sometimes make a lot of sense. Often > for these specific applications, the problems fade away and the advantages > can win out. > > Bill D. > > > > At 09:55 AM 12/24/2013, you wrote: > >> Let's say one could solve the problems of an in-wheel motor. Then, how >> much >> advantage would it have over using some sort of transxle and mounting the >> motor the chassis a little inwards from the wheel area. >> >> The only advantages I can think of are: >> - slightly less space used since the motor would be almost completely in >> the >> wheel well area, >> - ever so slightly less weight and resistive loss (no transaxle). >> >> Peri >> >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On >> Behalf >> Of Bill Dube >> Sent: 24 December, 2013 7:44 AM >> To: Electric Vehicle Discussion List >> Subject: Re: [EVDL] VW Bora will have Protean in-wheel motors >> >> I agree. Every car manufacturer has boldly announced in-wheel motors, >> built a prototype, and then made an embarrassing retraction. >> >> Sounds like a terrific idea, then they build one and learn for >> themselves the insurmountable safety issues of highway driving >> (uncommanded asymmetric torque, unacceptable unsprung weight, etc.), >> then as quietly as possible they bury all the prototypes and pretend it >> never happened. >> >> I wish they would publish a book or report on the bad experience, but I >> guess it is just too embarrassing. >> >> Bill Dube' >> >> On 12/23/2013 9:28 PM, Al wrote: >> > Sigh, in-wheel motors, again, when will they learn. >> > >> > ----- Original Message ----- From: "brucedp5" <[email protected]> >> > To: <[email protected]> >> > Sent: Monday, December 23, 2013 8:11 AM >> > Subject: [EVDL] EVLN: VW Bora will have Protean in-wheel motors >> > >> > >> > _______________________________________________ >> > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> > http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> > For EV drag racing discussion, please use NEDRA >> > (http://groups.yahoo.com/group/NEDRA) >> > >> > >> >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA >> (http://groups.yahoo.com/group/NEDRA) >> >> >> >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/ >> group/NEDRA) >> > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/ > group/NEDRA) > > -- Remember, it is not that the glass is half empty, in reality, the glass is merely twice the size that it needs to be! -TNT'82 -------------- next part -------------- An HTML attachment was scrubbed... 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