Raleigh SC30 converted to an electric bicycle with an aftermarket electric conversion hub motor kit
A wheel hub motor, also known as a hub motor or in-wheel motor, is a type of motor that is built into the hub of a wheel. These motors are often used in electric bicycles. While they were initially popular in early electric cars, they haven't been widely successful in modern production cars because it affects weight distribution of the car and increases unsprung weight .
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Bicycles
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Patents for electric bicycles with hub motors were granted as early as 1895.[3] Bicycle hub motors are simple, durable, and affordable compared to other designs, but less suitable for high speeds.[4] Hub motors rose in popularity over other designs in the late 2000s and 2010s.[5]
Automotive
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History
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1900 Lohner–Porsche "Mixte" racecar with four wheel-hub motors[6]Several electric, combustion, and steam powered in-wheel motor designs were patented in the 1880s and 1890s.[7] Among those who were awarded patents: Wellington Adams of St. Louis in 1884;[8] Edward Parkhurst of Woburn in 1890;[9] Albert Parcelle later in 1890;[10] Charles Theryc in 1896, who cites no transmission losses thanks to an absence of classic transmission rods from engines to wheels;[11] C F Goddard in 1896 who cites a piston hub motor for horseless carriages powered by expanding gas of some kind;[12] 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.[13]
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.[14] 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.[15][6]
Design
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Hub motors may be implemented with direct-drive or planetary gears.[16] They rotate the wheel either through an axial, inrunner, or outrunner rotor design, with either brushed or brushless commutator design.[17]
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.[18][19] High-voltage in-wheel motors must be robust against damage to their high-voltage cables and components.[2]
Unsprung weight
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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.[18] 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.[20]
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.[19]
Near-wheel motors
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2011 Mercedes-Benz SLS AMG E-Cell prototype with four near-wheel motors[21] which share the advantages of in-wheel motors while avoiding issues of unsprung weight and wearSimilar 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,[22] they avoid the risks associated with out-of-chassis high-voltage components,[2] and they simplify vehicle design and assembly. American Axle has developed 100 kW wheel-end motors which will debut in the REE Automotive commercial vehicle product line.[23]
Concept cars
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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.[24]
Other concept cars presented at auto shows include: Chevrolet Sequel, 2005;[25] Mitsubishi MIEV, 2005;[26] Hi-Pa Drive Mini QED, 2006;[27] Honda FCX concept, 2005;[28] Citroën C-Métisse, 2006;[29] Protean Electric Ford F-150, 2008;[30] Heuliez WILL using the Michelin Active Wheel suspension, 2008;[31] Peugeot BB1, 2009;[32] Hiriko Fold, shown in 2012, a folding urban car with a maximum speed of 50 km/h (31 mph)[33][34] with a motor, steering actuators, suspension, and brake integrated into each wheel, controlled with a drive-by-wire system;[35] FlatFormer, a concept 6x6 autonomous truck chassis, shown in 2019;[36] and various vehicles by Indigo Technologies since 2019.[2]
Concept cars that were announced without publicly presenting a physical model include: Siemens VDO eCorner concept, 2006;[37] and ZAP-X, 2007.[38]
Mini QED electric vehicle
Production vehicles
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Production vehicles with in-wheel motors include:
Planned production vehicles include:
See also
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References
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An e-bike is made up of three basic components: an electric motor, a battery, and a display. The motor is powered by the battery, and the display allows you to control how much power you desire. It's crucial to understand the many sorts of drive systems in order to determine which one is ideal for you.
Front motors, mid motors, and rear-hub motors are the three types of motors available for e-bikes. You should be aware that neither type of motor is superior to the other, but that they each offer distinct benefits based on your requirements.
In this in-depth guide, we’ll break down what each of these motors are and their unique pros and cons. We’ll also help you decide which motor is right for you.
Front e-Bike Motors
The motor is located in the center of the front wheel on front motor e-bikes. In front motor e-bikes, wiring and battery installation are relatively simple. The motor on a front motor e-bike usually propels the rider forward. In comparison to rear-motor e-bikes, the installation and configuration of front-motor e-bikes are quite simple. This is owing to the fact that most front-wheel motorcycles do not have a gear system. Front hub motors aid in the distribution of total load between the front and back wheels. The front wheel bears the front weight, while the back half is adjusted by human weight. The front motor system is also separated from the rest of the bike's components. This distinct location allows for easy servicing without interfering with the motor.
Pros of Front e-Bike Motors
Most old bikes may be retrofitted with new front hub motors, which are very light and straightforward to install.
Hub motors love to spin, so they're perfect for combining with gears. When using a hub motor, you don't have to push if you don't want to, hence these motors tend to provide more assistance than mid drive motors.
Hub motors are less expensive than mid-drive motors since they can be mounted on a standard bicycle frame.
Depending on the model and vendor, front hub motors are simple to replace or repair.
Front hub motors work well with hub gears, derailleurs, and belt-driven motorcycles.
Adult tricycles can readily accommodate front hub motors.
The drive chain on front hub motors does not require as much maintenance as it does on rear hub motors.
Because you don't have to change the gears when retrofitting with a front hub, and it's a relatively simple conversion, the cost of installation is usually lower. It's also simple to reverse the conversion if you want to switch bikes.
Cons of Front e-Bike Motors
One of the disadvantages of front-motor bikes is that they have lower-capacity motors, such as 250 W or 350 W. It's because, unlike rear-hub motor e-bikes, the bike's front fork lacks a structural base. As a result, your options for motor capacity become limited.
At low speeds, front motor e-bikes have a traction problem. This is related to the front motor versions' weight distribution.
Some vintage front motors are heavy, affecting the bike's weighting.
On dirt roads, front hubs lack grip, causing the wheel to spin upon start-up, especially when traveling uphill.
Because certain lighter hub motors offer less torque at low speeds, they should not be utilized for hauling, riding on mud, or doing a lot of uphill riding.
Changing a tire isn't as simple. It will require the use of a spanner.
Front brake pads are showing a little more wear.
Because they are not as efficient as mid-drive motorcycles, they require more battery power.
Mid e-Bike Motors
A mid-drive motor is situated close to the center of the e-bike, as the name implies, and this is its initial advantage over a rear-hub motor. Because of the motor's center location, the weight is evenly distributed between the front and back wheels. The handling and riding characteristics feel much more "natural" and balanced than with a rear-hub motor. Nothing, for example, drags down the rear wheel during jumps or when going over steps. Because the motor is located underneath the bottom bracket, it is also known as a bottom bracket motor. A specific frame is required for the mid-drive motor, which accommodates the complete motor block.
Pros of Mid e-Bike Motors
Its placement near the crank ensures proper weight distribution and a low center of gravity, which improves the bike's handling.
The mid-drive motor adjusts to changing riding conditions fast. The sensor system on the mid-drive motor, which is placed exactly at the crank, is the cause for this. The mid-drive motor responds quickly if the rider pushes harder on the pedals.
A mid-drive motor offers a wide range of gear options, including derailleur and hub gears, or internally geared hub and a belt.
Cons of Mid e-Bike Motors
Because the power is distributed by the drivetrain, there are more moving parts.
If your chain or belt fails, the bike loses motor assistance.
They’re more expensive.
Rear-Hub e-Bike Motors
The rear-hub motor is mounted on the bike's rear wheel. Its forces are also active there. The bike has a dynamic riding feel to it, as if it's being pushed from behind. Derailleurs with three chainrings are used on the rear-hub motor, allowing for a wide range of gear ratios. Rear-hub drives are most commonly employed in flat to mildly undulating and hilly terrain. That's when the rear-hub motor reaches its full capability and produces powerful thrust — enough to move heavy weights. On the other hand, e-mountain bikes and rear-hub motors are unlikely to become buddies. These motors overheat or don't provide enough support, especially on long steep climbs. The bike's off-road ability is also hampered by the rear-hub motor's hefty weight.
Pros of Rear-Hub e-Bike Motors
When climbing hills or traveling on the flats, mid-drive motors can be inconvenient. They necessitate more careful gear shifting.
Because of the greater power systems, the motor's life may be shortened. It may necessitate more frequent motor accessory replacements than on comparable models.
The cost of a mid-motor e-bike is usually more than the cost of the other two options since mid-motors are more complicated to construct than front-motor and rear-motor systems.
The motor supplies power and can recoup, i.e. collect energy to recharge the battery, when cycling downhill in its most efficient mode.
The rear-hub motor, in contrast to the mid-drive motor, relieves stress on the chain, resulting in reduced wear.
The majority of rear-hub motors are extremely quiet.
Cons of Rear-Hub e-Bike Motors
At high speeds, bikes with large rear motors may be prone to "popping wheelies." This isn't always enjoyable, and it can be harmful at times. When you accelerate from a red light or climb a slope, for example.
For persons who are heavier, a rear-motor is not the best option because of the weight on the rear wheel. This can cause premature rear wheel failure.
The motor is the most difficult part of the rear motor system to service or replace.
The option of rear disk brakes will be unavailable on rear motor e-bikes.
The rear wheels have a heavier load.
They can produce more noise when riding.
When compared to the mid-motor, they are less mechanically efficient.
Which Motor Type is Right for Me?
Despite their many advantages, e-bikes can also cause confusion and ownership anxiety due to the high technology curve that propels these bikes forward. As with all things electric, the logic is that delaying your purchase will allow you to take advantage of the most recent technology.
In actuality, each motor type, whether front or rear hub, or mid-drive, has benefits and drawbacks. It all depends on how you want to utilize your bike, the type of bike you have, and your riding style. Most e-bikers have seen folks riding about on entirely inappropriate and extremely costly e-mountain bikes because that's what they've been told is best to buy, even if they're only riding a few miles to work each day. People commute small distances on bikes that cost $6,500 when a perfectly suitable bike may be had for less than half that price. The correct engine for your e-bike depends on your budget, level of comfort, and intended use.
The greatest e-bike motors will strike a balance between power and weight in order to provide optimum pedal assistance without weighting down and slowing down the bike. Of course, e-bike motors are built into the bike and aren't currently a component that can be swapped out or upgraded, so knowing what you're getting into when shopping for the best electric bikes is essential. Hopefully, this tutorial will serve as a useful resource!