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{{Short description|Electric motor in the middle of a wheel}}
{{Use dmy dates|date=January 2012}}
{{Refimprove|date=August 2009}} {{Use dmy dates|date=April 2021}}
] ] with an aftermarket electric conversion hub motor kit]]
The '''wheel hub motor''' (also called '''wheel motor''', '''wheel hub drive''', '''hub motor''' or '''in-wheel motor''') is an ] that is incorporated into the hub of a wheel and drives it directly.


A '''wheel hub motor''', '''hub motor''', or '''in-wheel motor''' is a ] that is incorporated into the ] of the wheel. Wheel-hub motors are commonly found on ]s. Electric hub motors were well received in early ]s, but have not been commercially successful in modern production cars<ref>{{cite news |title=Wheel Motors to Drive Dutch Buses |url=https://www.technologyreview.com/2009/03/23/31935/wheel-motors-to-drive-dutch-buses/ |date=23 March 2009 |website=]}}</ref><ref name="highvoltage">{{cite news |url=https://www.economist.com/science-and-technology/2019/07/11/a-new-type-of-engine-for-electric-cars|title=A new type of engine for electric cars|date=2019-07-11|newspaper=The Economist|access-date=2019-08-31|issn=0013-0613}}</ref> because they negatively affect vehicle handling due to higher dynamic ]<ref name="AVEC10" /> and their placement makes them prone to damage.<ref name="highvoltage" />
==Uses in current and future vehicles==
* They are commonly found on ]s.<ref>http://www.electricrider.com/crystalyte/</ref>
* Wheel motors are applied in industry, e.g. driving wheels that are part of assembly lines.
* They have been little applied in cars, yet that is what they were invented for. (See ])
* Hub motors can also be found on buses.<ref>{{cite web |title=Wheel Motors to Drive Dutch Buses |url=http://www.technologyreview.com/energy/22328/ |date=23 March 2009 |accessdate=23 November 2009 |publisher=]}}</ref>


==Bicycles==
⚫ === Concept cars ===
{{Main|Electric bicycle}}
⚫ ]
Patents for electric bicycles with hub motors were granted as early as 1895.<ref>({{US Patent|552271}}</ref> Bicycle hub motors are simple, durable, and affordable compared to other designs, but less suitable for high speeds.<ref>{{cite web |url=https://www.nationalgeographic.com/environment/article/electric-bike-sustainable-transportation |title=Are electric bikes the future of green transportation? |first=Elaina |last=Zachos |date=June 16, 2023 |website=National Geographic}}</ref> Hub motors rose in popularity over other designs in the late 2000s and 2010s.<ref>{{cite web |url=https://www.cyclist.co.uk/in-depth/introduction-to-electric-bikes-everything-you-need-to-know |title=Introduction to electric bikes: Everything you need to know |date=April 18, 2017 |website=Cyclist |location=UK}}</ref>
Several ]s have been developed using in-wheel motors:
* ]'s Mini QED in 2006, and other cars using its ]
* ] ] concept model in 2005
* ] ] (bought by ]) eCorner concept in 2006<ref>{{cite web |title=SIEMENS VDO'S BY-WIRE TECHNOLOGY TURNS THE eCORNER |url=http://usa.vdo.com/press/releases/chassis-and-carbody/2006/SV_20061016_i.htm |date=16 October 2006 |publisher=] |accessdate=15 September 2009}} {{Dead link|date=October 2010|bot=H3llBot}}</ref><ref>{{cite web |title=Car motors will disappear – into the wheels |url=http://usa.vdo.com/press/pictures/chassis-carbody/sv-2000608-001e-005.htm |date=8 August 2006 |publisher=] |accessdate=15 September 2009}} {{Dead link|date=October 2010|bot=H3llBot}}</ref>
* ] WILL using the ] ] (which incorporates motorized ] as well) in 2008<ref>{{cite web |title=MICHELIN ACTIVE WHEEL Press Kit |url=http://www.michelin.com/corporate/document.DocumentRepositoryServlet?codeDocument=7735&codeRubrique=salonauto2008&codeRepository=MICHCORP&lang=EN |date=26 September 2008 |publisher=] |accessdate=15 September 2009}}</ref>
* The ] in 2007 "would use high-tech electric hub motors at all four wheels, delivering 644 horsepower to the ground from a lithium-ion battery pack. The hub motors would eliminate the need for transmission, axles and conventional brakes, opening up space beneath the floor for a giant battery pack."<ref>{{cite news| url=http://select.nytimes.com/preview/2007/09/23/automobiles/1154690129008.html | work=The New York Times | title=They're Electric, but Can They Be Fantastic? | first=Lawrence | last=Ulrich | date=23 September 2007}}</ref>
* The ] in 2009 incorporates rear in-wheel motors designed with ].<ref>{{cite web |url=http://www.greencarcongress.com/2009/09/hybrid4-bb1-20090915.html |title=Peugeot Shows Two HYbrid4 Concepts, New BB1 EV Concept at Frankfurt |date=15 September 2009 |publisher=] |accessdate=31 May 2010}}</ref>
* The Protean Ford F-150 All-Electric Pickup Truck by ] uses four in-wheel motors.<ref>{{cite web |url=http://news.pickuptrucks.com/2011/05/driven-protean-ford-f-150-all-electric-pickup-truck.html |title=Test drive of new in-wheel electric motored pickup truck |date=15 September 2009 |accessdate=31 May 2011}}</ref>


==Mechanism== ==Automotive==
⚫ ===History===
Hub motor electromagnetic fields are supplied to the stationary windings of the motor. The outer part of the motor follows, or tries to follow, those fields, turning the attached wheel. In a brushed motor, energy is transferred by brushes contacting the rotating shaft of the motor. Energy is transferred in a brushless motor electronically, eliminating physical contact between stationary and moving parts. Although ] technology is more expensive, most are more efficient and longer-lasting than brushed motor systems.
] with two front-wheel hub motors<ref name="Frankenberg1961" />]]
] "Mixte" racecar with four wheel-hub motors<ref name="Frankenberg1961" />]]


Several electric, combustion, and steam powered in-wheel motor designs were patented in the 1880s and 1890s.<ref>{{cite web |url=https://www.hemmings.com/stories/2014/02/12/ferdinand-porsche-joseph-ledwinka-and-the-invention-of-the-electric-hub-motor |title= Ferdinand Porsche, Joseph Ledwinka, and the invention of the electric hub motor |first=Daniel |last=Strohl |date=February 12, 2014 | website=Hemmings}}</ref> Among those who were awarded patents: Wellington Adams of St. Louis in 1884;<ref name="Adams1884">{{US Patent|300,827}}</ref> Edward Parkhurst of Woburn in 1890;<ref name="Parkhurst1890">{{US Patent|422,149}}</ref> Albert Parcelle later in 1890;<ref name="Parcelle">{{US Patent|433,180}}</ref> Charles Theryc in 1896, who cites no transmission losses thanks to an absence of classic transmission rods from engines to wheels;<ref>{{US Patent|572,036}}</ref> C F Goddard in 1896 who cites a piston hub motor for horseless carriages powered by expanding gas of some kind;<ref>{{US Patent|574,200}}</ref> and W C Smith in 1897 who cites an explosive gas expansion motor inside a wheel hub that utilized cams on a track in the hub to transmit power to the wheel.<ref>{{US Patent|593,248}}</ref>
Electric motors have their greatest torque at startup, making them ideal for vehicles as they need the most torque at startup too. The idea of "revving up" so common with internal combustion engines is unnecessary with electric motors. Their greatest torque occurs as the rotor first begins to turn, which is why electric motors do not require a transmission. A gear-down arrangement may be needed, but unlike in a transmission normally paired with a combustion engine, no shifting is needed for electric motors.{{Citation needed|date=March 2011}}


An electric wheel hub motor car was raced by ] in 1897 in ], Austria. He developed his first cars as electric cars with electric wheel hub motors that ran on batteries.<ref>{{cite web |url=https://www.biography.com/business-leaders/ferdinand-porsche |title=Ferdinand Porsche |date=April 5, 2021 |website=Biography.com}}</ref> A racecar by ] fitted with four wheel-hub motors debuted at the ] in Paris in 1900. Alongside it a commercial model was introduced, the Lohner–Porsche Chaise, with two front wheel-hub motors. It was well-received, and several models based on its design were produced by Lohner and other manufacturers until the 1920s.<ref name="WorldGuide1987">{{cite encyclopedia |url=https://archive.org/details/worldguidetoauto0000unse_p7u4/page/294/mode/2up?q=%22Lohner+Porsche%22 |page=294 |encyclopedia=The World Guide to Automobile Manufacturers |title=Lohner |year=1987 |publisher=]}}</ref><ref name="Frankenberg1961">{{cite book |title=Porsche – the Man and His Cars |page=58 |first=Richard |last=von Frankenberg |year=1961 |publisher=Robert Bentley}}</ref>
Wheel hub motors are increasingly common on electric bikes and electric scooters in some parts of the world, especially Asia.<ref>http://www.ebikes.ca/hubmotors.shtml</ref><ref>http://www.electricrider.com/crystalyte/motordimensions.htm</ref>


===Design===
==Comparison with conventional EV design in automobiles==
Hub motors may be implemented with ] or ].<ref>{{cite web |url=https://www.ebikeschool.com/geared-hub-motors-vs-gearless-hub-motors/ |title=Geared Hub Motors Vs Gearless Hub Motors |website=EbikeSchool.com |access-date=2023-06-24}}</ref> They rotate the wheel either through an ], ], or ] rotor design, with either brushed or ] commutator design.<ref>{{cite web |url=https://www.machinedesign.com/motors-drives/article/21833665/designing-inhub-brushless-motors |title=Designing In-Hub Brushless Motors |date=July 22, 2014 |first=Lowell |last=Christensen |website=Machine Design}}</ref>
Compared with the conventional ] design with one motor situated centrally driving two (sometimes four) wheels by axles, the wheel motor arrangement has certain advantages and disadvantages:


]
===Drive by wire===
Cars with electronic control of brakes and acceleration provide more opportunities for computerized vehicle dynamics such as:


Hub motors are attractive from a design standpoint because of their flexibility. They can be used for front-, rear-, or ]. They are compact and hence allow for more room for passengers, cargo, or other vehicle components. They allow for better weight distribution compared to a single motor, and they eliminate the need for many of the drive components in traditional vehicles like transmissions, differentials, and axles, which reduces wear and mechanical losses.<ref name="AVEC10" /><ref name="Mraz2010" /> High-voltage in-wheel motors must be robust against damage to their high-voltage cables and components.<ref name="highvoltage" />
* Active cruise control, where the vehicle can maintain a given distance from a vehicle ahead
* Collision avoidance, where the vehicle can automatically brake to avoid a collision
* Emergency brake assist, where the vehicle senses an emergency stop and applies maximum braking
* Active software differentials, where individual wheel speed is adjusted in response to other inputs
* Active brake bias, where individual wheel brake effort is adjusted in real time to maintain vehicle stability
* Brake steer, where individual wheel brake bias is adjusted to assist steering (similar to a tracked vehicle like a ])


⚫ ===Unsprung weight===
While some of these features have started to appear as options for some internal combustion engine vehicles, optional ABS brakes can add up to $2,000 dollars to the cost of a base model.<ref> http://www.openroad.com.au/motoring_roadsafety_priceofsafety.asp</ref>
One disadvantage of a wheel hub motor is that the weight of the motor is not supported by the suspension's ]s, adding to the vehicle's ] which adversely affects handling and ride quality. Despite this reduction in ride quality with electric hub motors, it is still better than the ride quality of equivalent combustion engine vehicles, but vehicle handling is still negatively affected due to higher dynamic ].<ref name="AVEC10">{{cite conference |last1=Vos |first1=R. |last2=Besselink |first2=I. J. M. |last3=Nijmeijer |first3=H. |title=Influence of in-wheel motors on the ride comfort of electric vehicles |conference =Proceedings of the 10th International Symposium on Advanced Vehicle Control (AVEC10) |date=22-26 August 2010 |location=Loughborough, United Kingdom |pages=835–840}}</ref> ] and ] found that most negative effects of added unsprung mass could be eliminated by adding suspension damping, and that the ability to utilize accurate torque vectoring actually improved car's handling so much that the net effect of the whole arrangement was positive.<ref>{{cite journal |last1=Whitehead |first1=Andrew |last2=Hilton |first2=Chris |title=In-Wheel Motors Roll Again |journal=IEEE Spectrum |issue=July 2018 |page=27 |quote=The Lotus engineers were able to eliminate much of the effect of the added unsprung mass by using slightly more suspension damping. What's more, they found that when that unsprung mass came from actual motors attached to the wheels, the ability to power each side of the car independently improved the car's handling substantially. We've now carried out similar studies on other vehicles. And in all cases, we've found that once the dampers are retuned and we add individual wheel control, the net effect on the vehicle's handling is for the better. So unsprung mass really isn't a showstopper after all.}}</ref>


Without being supported by the suspension's shock absorbers, in-wheel motors are themselves less shielded both from shocks and debris, reducing their durability. Some designs reduce unsprung weight by reducing the weight of the motor, for example by using a ] or ] coil windings. These weight-saving designs may have a negative effect on motor durability.<ref name="Mraz2010">{{cite web |url=https://www.machinedesign.com/markets/automotive/article/21831614/hub-motors-for-allelectric-vehicles-still-have-some-technological-challenges-to-overcome |title=Hub Motors for All-Electric Vehicles Still Have Some Technological Challenges to Overcome |date=August 10, 2010 |first=Stephen J. |last=Mraz |website=Machine Design}}</ref>
As wheel motors brake and accelerate a vehicle with a single solid state electric/electronic system many of the above features can be added as software upgrades rather than requiring additional systems/hardware be installed like with ABS etc. This should lead to cheaper active dynamic safety systems for wheel motor equipped road vehicles.


===Weight savings=== ===Near-wheel motors===
] with four near-wheel motors<ref>{{cite news |url=https://www.autoblog.com/2011/01/10/mercedes-benz-sls-amg-e-cell-detroit-2011/ |title= Detroit 2011: Mercedes-Benz SLS AMG E-Cell is the color of electric hotness |date=January 10, 2011 |website=Autoblog}}</ref> which share the advantages of in-wheel motors while avoiding issues of unsprung weight and wear]]
Eliminating mechanical transmission inc. gearboxes, differentials, drive shafts and axles provides a significant weight and manufacturing cost saving, while also decreasing the environmental impact of the product.{{cn|date=October 2011}}


Similar to ''in''-wheel motors, electric vehicles can be designed with ''near''-wheel motors, sometimes called wheel-end motors. This design shares the same advantages as in-wheel motors while avoiding unsprung weight and wear issues, as the motors are near the wheels but inside the chassis, supported by the suspension. Near-wheel motors are less compact than in-wheel motors, but as of 2022 they are more reliable and more cost-effective,<ref>{{cite journal |title=Route Towards Road Freight Electrification in India: Examining Battery Electric Truck Powertrain and Energy Consumption |first1=Sreedhar |last1=Madichetty |first2=Avram John |last2=Neroth |first3=Sukumar |last3=Mishra |first4=B. Chitti |last4=Babu |journal=Chinese Journal of Electrical Engineering |volume=8 |issue=3 |date=September 2022 |pages=57–75 |doi=10.23919/CJEE.2022.000026|s2cid=252841869 |doi-access=free }}</ref> they avoid the risks associated with out-of-chassis high-voltage components,<ref name="highvoltage" /> and they simplify vehicle design and assembly.<ref name="detroitnews2023" />
⚫ ===Unsprung weight concerns===


] has developed 100&nbsp;kW and 150&nbsp;kW wheel-end motors through a project funded by the ] for the commercialization of clean-energy low-cost wheel-end motors. Costs were lowered by integrating the motor, inverter, and gear reduction into a single unit, and by avoiding ] elements.<ref>{{citation |url=https://www.energy.gov/eere/vehicles/articles/low-cost-high-performance-hre-free-3-1-electric-drive-unit |contribution=Low Cost, High-Performance, HRE-Free 3-In-1 Electric Drive Unit |first=David |last=Crecelius |date=June 22, 2021 |title=2021 DOE Vehicle Technologies Office Annual Merit Review about Electrification |publisher=]}}</ref> The 100&nbsp;kW 3-in-1 wheel-end drive unit has become commercially available in the ] vehicle product line.<ref name="detroitnews2023">{{cite news |url=https://www.detroitnews.com/story/business/autos/2023/01/26/american-axle-ev-plans-independence-innovation/69766807007/ |archive-url=https://web.archive.org/web/20230126052129/https://eu.detroitnews.com/story/business/autos/2023/01/26/american-axle-ev-plans-independence-innovation/69766807007/ |archive-date=January 26, 2023 |date=January 26, 2023 |title=American Axle plows ahead with independence, innovation |first=Breana |last=Noble |website=The Detroit News}}</ref>
The major disadvantage of Wheel hub motors are that the weight of the electric motors would increase the ], which adversely affects handling and ride (the wheels are more sluggish in responding to road conditions, especially fast motions over bumps, and transmit the bumps to the chassis instead of absorbing them). Most conventional electric motors include ferrous material composed of laminated ]. This ferrous material contributes most of the weight of electric motors. To minimize this weight several recent wheel motor designs have minimized the electrical steel content of the motor by utilizing a coreless design with ] coil windings to reduce eddy current losses. This significantly reduces wheel motor weight and therefore unsprung weight.{{cn|date=November 2011}}


⚫ ===Concept cars===
Another method used is to replace the cast iron friction brake assembly with a wheel motor assembly of similar weight. This results in no net gain in unsprung weight and a car capable of braking up to 1G.<ref>http://www.youtube.com/watch?v=i1uTR-8KarE</ref> A good example of this is the Michelin ] motor as fitted to the ] Will that results in an unsprung weight of 35&nbsp;kg on the front axle which compares favorably to a small car such as a Renault Clio that has 38&nbsp;kg of unsprung weight on its front axle.<ref>http://www.causecast.org/news_items/7667-michelin-unveils-active-wheel-in-affordable-electric-car</ref>
An early modern ] utilizing electric hub motors was the IZA, presented in at the ] conference in 1997, built with four {{cvt|25|kW|hp|0}} motors.<ref>{{cite thesis |url=https://www.diva-portal.org/smash/get/diva2:503940/FULLTEXT01.pdf |title=Wheel Corner Modules: Technology and Concept Analysis |first=Johan |last=Hag |publisher=] |year=2011 |page=8}}</ref>


Other concept cars presented at auto shows include: ], 2005;<ref name=RSC>{{cite journal |title=Sustainable transportation based on electric vehicle concepts: a brief overview |url=http://www.rsc.org/Publishing/Journals/EE/article.asp?doi=c001674h|last1=Eberle|first1=Ulrich|first2=Rittmar|last2=von Helmolt |publisher=]| journal=Energy & Environmental Science |date=2010-05-14| volume=3 | issue=6 | page=689 | doi=10.1039/C001674H | access-date=2010-06-08}}</ref> ], 2005;<ref>{{cite news |url=https://www.nbcnews.com/id/wbna7816102 |title=Mitsubishi unveils electric car for 2010 |website=NBC News |date=May 11, 2005}}</ref> ] Mini QED, 2006;<ref>{{cite news |url=https://www.wired.com/2006/10/lets-motor-motor-motor-motor/ |title=Let's Motor, Motor, Motor, Motor |first=Michael |last=Spinelli |date=October 1, 2006 |website=]}}</ref> ] concept, 2005;<ref>{{cite web |title=Honda Worldwide - Tokyo 2005 |url=http://world.honda.com/Tokyo2005/fcx/index02.html |archive-url=https://web.archive.org/web/20060501144651/http://world.honda.com/Tokyo2005/fcx/index02.html |archive-date=May 1, 2006 |access-date=September 22, 2023 |website=Honda.com}}</ref> ], 2006;<ref>{{cite news |url=https://www.motor1.com/news/227536/concept-we-forgot-citroen-c-metisse/ |title=2006 Citroën C-Métisse: Concept We Forgot |first=Adrian |last=Padeanu |date=January 17, 2018 |website=]}}</ref> ] Ford F-150, 2008;<ref>{{cite news |url=http://news.pickuptrucks.com/2011/05/driven-protean-ford-f-150-all-electric-pickup-truck.html |title=Driven: Protean Ford F-150 All-Electric Pickup Truck |date=May 12, 2017 |first=Ben |last=Wojdyla |website=PickupTrucks.com}}</ref> ] WILL using the Michelin ] suspension, 2008;<ref>{{cite news |url=https://www.autoblog.com/2008/10/09/paris-2008-heuliez-michelin-and-orange-wrap-a-revolution-in-a/ |title= Paris 2008: Heuliez, Michelin and Orange wrap a revolution in a plain package |first=Domenick |last=Yoney |date=October 9, 2008 |website=Autoblog}}</ref> ], 2009;<ref>{{cite web |url=http://www.greencarcongress.com/2009/09/hybrid4-bb1-20090915.html |title=Peugeot Shows Two HYbrid4 Concepts, New BB1 EV Concept at Frankfurt |date=15 September 2009 |website=Green Car Congress |access-date=31 May 2010}}</ref> ], shown in 2012, a folding ] with a maximum speed of {{convert|50|km/h|abbr=on|0}}<ref name=WeirdUK>{{cite magazine|title=Hiriko electric city car folds up to save space|url=https://www.wired.co.uk/news/archive/2012-01/26/hiriko-city-car|magazine=Wired UK|access-date=1 February 2012|date=26 January 2012}}</ref><ref name=Hiriko>{{cite web|title=The Folding Electric Car|url=http://english.kompas.com/read/2012/01/30/13002021/The.Folding.Electric.Car|publisher=Kompas.com|first=Jimmy |last=Hitipeuw|date=30 January 2012|access-date=16 July 2012|url-status=dead|archive-url=https://web.archive.org/web/20120202112627/http://english.kompas.com/read/2012/01/30/13002021/The.Folding.Electric.Car|archive-date=2 February 2012}}</ref> with a motor, steering actuators, suspension, and brake integrated into each wheel, controlled with a ] system;<ref>{{cite news|url=http://www.gizmag.com/hiriko-folding-electric-car/21506/|title=Hiriko - the fold-up electric two-seater set for 2013|first=James |last=Holloway|work=Gizmag|date=20 February 2012 |access-date=26 July 2012}}</ref> FlatFormer, a concept 6x6 autonomous truck chassis, shown in 2019;<ref name="Flatformer2019">{{cite news |title=REE Partnership With Hino Shows More On In-Wheel Motor Tech |url=https://insideevs.com/news/377977/ree-hino-in-wheel-motor/ |date=October 23, 2019 |first=Gustavo |last=Henrique Ruffo |website=InsideEVs}}</ref> various vehicles by Indigo Technologies since 2019;<ref name="highvoltage" /> and an ] in 2022.<ref>{{citation |url=https://newatlas.com/automotive/aptera-gamma-prototype-solar-electric-vehicle/ |title=Aptera Gamma prototype SEV makes public debut in San Diego |first=Paul |last=Ridden |date=September 12, 2022 |website=NewsAtlas}}</ref>
⚫ ==History==
* Wellington Adams of St. Louis first conceived of building an electric motor directly in the vehicle wheel, though it was attached via complicated gearing. The Adams patent is US # 300,827 in 1884.
* Albert Parcelle of Boston, MA developed the first fully incorporated Wheel hub motor in his "Electro-Motor Traction Wheel" and patented it in patent US # 433,180 in 1890.
* The motor was incorporated into the wheel without gearing and addressed torque considerations through the use of a new high torque, low rpm motor invented by Edward Parkhurst of Woburn, MA in patent # 422,149 in 1890 (and mismentioned in Parcelle's patent as #320,699).
* An early Wheel hub electric motor was invented by Frenchman Charles Theryc and patented in 1896 as US patent 572,036 entitled Wheel with Electric Motor hub for Vehicles. In the patent he explained all advantages including no transmission losses because of the absence of classic transmission rods from engines to wheels.
* Not all wheel hub motors were electric. C F Goddard in 1896 invented a piston hub motor for horseless carriages patented in US # 574,200. He envisioned it powered by expanding gas of some kind. His offcenter flexible bent spoke designs later appeared in the Apollo moon rovers' wheels in 1960s.
* In patent # 593,248 W C Smith in 1897 developed another explosive gas expansion motor inside a wheel hub that utilized cams on a track in the hub to transmit power to the wheel.


Concept cars that were announced without publicly presenting a physical model include: ] ] eCorner concept, 2006;<ref>{{cite news |url=https://www.autoblog.com/2006/08/10/siemens-vdo-announces-ecorner-motor-in-hub-concept/ |title=Siemens VDO announces eCorner motor-in-hub concept |first=Eric |last=Bryant |date=August 10, 2006 |website=Autoblog}}</ref> and ], 2007.<ref>{{cite news| url=https://www.nytimes.com/2007/09/23/automobiles/23AUTO.html | website=The New York Times | title=They're Electric, but Can They Be Fantastic? | first=Lawrence | last=Ulrich | date=23 September 2007}}</ref>
The electric wheel hub motor was raced by ] in 1897 in ], Austria. Porsche's first engineering training was electrical, not internal combustion based. As a result he developed his first cars as electric cars with electric wheel hub motors that ran on batteries. The ], fitted with one wheel motor in each of the front wheels, appeared at the ] in Paris in 1900 and created a sensation in the young automobile world. In the following years, 300 Lohne Porsches were made and sold to wealthy buyers.<ref>http://www.porsche.com/usa/aboutporsche/porschehistory/milestones/</ref>


{{Gallery
] had hub motors.]]
|width=200 | height=200
|align=center
⚫ |File:PMLMini QED-wheel.jpg|Mini QED electric vehicle
|File:MZKT open day 2019 p06.jpg|] truck. Each wheel has its own electric motor
|File:Hiriko 1.jpg|] with in-wheel motor, steering actuators, suspension, and braking, controlled by a drive-by-wire system
}}


===Production vehicles===
Eventually the growth in power of the gasoline engine overtook the power of the electric wheel hub motors and this made up for any losses through a transmission. As a result autos moved to gas engines with transmissions, but they were never as efficient as electric wheel hub motors.
Production vehicles with in-wheel motors include:
* ] Chaise, Mixte, and others. Several models based on this design were produced by Lohner and other manufacturers in the early 1900s.<ref name="WorldGuide1987" /><ref name="Frankenberg1961" />
* ], briefly produced in 2022 before its manufacturer filed for bankruptcy.<ref name=AutoExpress>{{cite news |title=Lightyear unveils long-range solar-electric car |url=https://www.autoexpress.co.uk/car-news/107239/lightyear-unveils-long-range-solar-electric-car |first=Luke |last=Wilkinson|work=Auto Express |location=UK |access-date=26 June 2019 |date=25 June 2019}}</ref><ref>{{cite news |title=Lightyear 0 Production On Hold As Company Focuses On Affordable Model |url=https://insideevs.com/news/632703/lightyear-0-production-on-hold/ |website=InsideEVs |language=en}}</ref>
* ], briefly produced in 2022 before its manufacturer filed for bankruptcy.<ref>{{cite news |url=https://www.caranddriver.com/news/a44359321/lordstown-files-for-bankruptcy-report/ |title=Lordstown Files for Bankruptcy, Endurance Pickup Assets up for Sale |first=Caleb |last=Miller |date=June 27, 2023 |website=]}}</ref>


Planned production vehicles include:
⚫ == See also ==

* ] plans producing by 2025 a vehicle with in-wheel motors developed by DeepDrive.<ref>{{citation |url=https://www.autoevolution.com/news/crazy-bmw-coupe-prototype-with-neue-klasse-dna-and-wheel-hub-motors-emerges-from-the-void-236549.html |title=Crazy BMW Coupe Prototype With Neue Klasse DNA and Wheel Hub Motors Emerges From the Void |date=July 5, 2024 |first=Cristian |last=Agatie |website=AutoEvolution}}</ref>

⚫ ==See also==
* ] * ]
* ]
* ]
* ]
* ] * ]


==References== ==References==
{{reflist|colwidth=30em}} {{Reflist|30em}}


==External links== ==External links==
{{Commons category-inline|In-wheel motors}} {{Commons category|In-wheel motors}}
*, presented in May 2005, is fitted with wheel motors at the rear.
*A Proposal to adapt


{{DEFAULTSORT:Wheel Hub Motor}} {{DEFAULTSORT:Wheel Hub Motor}}
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Latest revision as of 23:35, 21 December 2024

Electric motor in the middle of a wheel

Raleigh SC30 converted to an electric bicycle with an aftermarket electric conversion hub motor kit

A wheel hub motor, hub motor, or in-wheel motor is a motor that is incorporated into the hub of the wheel. Wheel-hub motors are commonly found on electric bicycles. Electric hub motors were well received in early electric cars, but have not been commercially successful in modern production cars because they negatively affect vehicle handling due to higher dynamic wheel load and their placement makes them prone to damage.

Bicycles

Main article: Electric bicycle

Patents for electric bicycles with hub motors were granted as early as 1895. Bicycle hub motors are simple, durable, and affordable compared to other designs, but less suitable for high speeds. Hub motors rose in popularity over other designs in the late 2000s and 2010s.

Automotive

History

1900 Lohner-Porsche "Chaise" battery electric vehicle with two front-wheel hub motors
1900 Lohner–Porsche "Mixte" racecar with four wheel-hub motors

Several electric, combustion, and steam powered in-wheel motor designs were patented in the 1880s and 1890s. Among those who were awarded patents: Wellington Adams of St. Louis in 1884; Edward Parkhurst of Woburn in 1890; Albert Parcelle later in 1890; Charles Theryc in 1896, who cites no transmission losses thanks to an absence of classic transmission rods from engines to wheels; C F Goddard in 1896 who cites a piston hub motor for horseless carriages powered by expanding gas of some kind; and W C Smith in 1897 who cites an explosive gas expansion motor inside a wheel hub that utilized cams on a track in the hub to transmit power to the wheel.

An electric wheel hub motor car was raced by Ferdinand Porsche in 1897 in Vienna, Austria. He developed his first cars as electric cars with electric wheel hub motors that ran on batteries. A racecar by Lohner–Porsche fitted with four wheel-hub motors debuted at the World Exhibition in Paris in 1900. Alongside it a commercial model was introduced, the Lohner–Porsche Chaise, with two front wheel-hub motors. It was well-received, and several models based on its design were produced by Lohner and other manufacturers until the 1920s.

Design

Hub motors may be implemented with direct-drive or planetary gears. They rotate the wheel either through an axial, inrunner, or outrunner rotor design, with either brushed or brushless commutator design.

Honda FCX Concept 2005 in-wheel motor with high-voltage wires in orange. Running high voltage outside the chassis can be avoided by using near-wheel motors, which have similar advantages to in-wheel motors.

Hub motors are attractive from a design standpoint because of their flexibility. They can be used for front-, rear-, or individual-wheel drive. They are compact and hence allow for more room for passengers, cargo, or other vehicle components. They allow for better weight distribution compared to a single motor, and they eliminate the need for many of the drive components in traditional vehicles like transmissions, differentials, and axles, which reduces wear and mechanical losses. High-voltage in-wheel motors must be robust against damage to their high-voltage cables and components.

Unsprung weight

One disadvantage of a wheel hub motor is that the weight of the motor is not supported by the suspension's shock absorbers, adding to the vehicle's unsprung weight which adversely affects handling and ride quality. Despite this reduction in ride quality with electric hub motors, it is still better than the ride quality of equivalent combustion engine vehicles, but vehicle handling is still negatively affected due to higher dynamic wheel load. Protean Electric and Lotus found that most negative effects of added unsprung mass could be eliminated by adding suspension damping, and that the ability to utilize accurate torque vectoring actually improved car's handling so much that the net effect of the whole arrangement was positive.

Without being supported by the suspension's shock absorbers, in-wheel motors are themselves less shielded both from shocks and debris, reducing their durability. Some designs reduce unsprung weight by reducing the weight of the motor, for example by using a coreless design or Litz wire coil windings. These weight-saving designs may have a negative effect on motor durability.

Near-wheel motors

2011 Mercedes-Benz SLS AMG E-Cell prototype with four near-wheel motors which share the advantages of in-wheel motors while avoiding issues of unsprung weight and wear

Similar to in-wheel motors, electric vehicles can be designed with near-wheel motors, sometimes called wheel-end motors. This design shares the same advantages as in-wheel motors while avoiding unsprung weight and wear issues, as the motors are near the wheels but inside the chassis, supported by the suspension. Near-wheel motors are less compact than in-wheel motors, but as of 2022 they are more reliable and more cost-effective, they avoid the risks associated with out-of-chassis high-voltage components, and they simplify vehicle design and assembly.

American Axle has developed 100 kW and 150 kW wheel-end motors through a project funded by the United States Department of Energy for the commercialization of clean-energy low-cost wheel-end motors. Costs were lowered by integrating the motor, inverter, and gear reduction into a single unit, and by avoiding heavy rare earth elements. The 100 kW 3-in-1 wheel-end drive unit has become commercially available in the REE Automotive vehicle product line.

Concept cars

An early modern concept car utilizing electric hub motors was the IZA, presented in at the IEEE conference in 1997, built with four 25 kW (34 hp) motors.

Other concept cars presented at auto shows include: Chevrolet Sequel, 2005; Mitsubishi MIEV, 2005; Hi-Pa Drive Mini QED, 2006; Honda FCX concept, 2005; Citroën C-Métisse, 2006; Protean Electric Ford F-150, 2008; Heuliez WILL using the Michelin Active Wheel suspension, 2008; Peugeot BB1, 2009; Hiriko Fold, shown in 2012, a folding urban car with a maximum speed of 50 km/h (31 mph) with a motor, steering actuators, suspension, and brake integrated into each wheel, controlled with a drive-by-wire system; FlatFormer, a concept 6x6 autonomous truck chassis, shown in 2019; various vehicles by Indigo Technologies since 2019; and an Aptera Motors prototype in 2022.

Concept cars that were announced without publicly presenting a physical model include: Siemens VDO eCorner concept, 2006; and ZAP-X, 2007.

  • Mini QED electric vehicle Mini QED electric vehicle
  • MAZ-7907 truck. Each wheel has its own electric motor MAZ-7907 truck. Each wheel has its own electric motor
  • Hiriko Fold with in-wheel motor, steering actuators, suspension, and braking, controlled by a drive-by-wire system Hiriko Fold with in-wheel motor, steering actuators, suspension, and braking, controlled by a drive-by-wire system

Production vehicles

Production vehicles with in-wheel motors include:

  • Lohner–Porsche Chaise, Mixte, and others. Several models based on this design were produced by Lohner and other manufacturers in the early 1900s.
  • Lightyear 0, briefly produced in 2022 before its manufacturer filed for bankruptcy.
  • Lordstown Endurance, briefly produced in 2022 before its manufacturer filed for bankruptcy.

Planned production vehicles include:

  • BMW plans producing by 2025 a vehicle with in-wheel motors developed by DeepDrive.

See also

References

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