![20210921 Individual wheel drive - conceptual block diagram](https://upload.wikimedia.org/wikipedia/commons/6/64/20210921_Individual_wheel_drive_-_conceptual_block_diagram.svg)
Individual-wheel drive or IWD is a wheeled
vehicle
A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), wa ...
with a
drivetrain
A drivetrain (also frequently spelled as drive train or sometimes drive-train) is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the drivetrain is the components o ...
that allows all
wheel
A wheel is a circular component that is intended to rotate on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machines. Wheels, in conjunction wi ...
s to receive
torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...
from several motors independent of each other. The term was coined to identify those electric vehicles whereby each wheel is driven by its own individual electric motor.
These vehicles inherently have a range of characteristics built-in that are more commonly attributed to
four-wheel drive
Four-wheel drive, also called 4×4 ("four by four") or 4WD, refers to a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case ...
vehicles or vehicles with extensive control systems. These characteristics can be:
*
Four-wheel drive
Four-wheel drive, also called 4×4 ("four by four") or 4WD, refers to a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case ...
, i.e. the distribution of available power to all the wheels of a four-wheeled vehicle.
*
Anti-lock braking system
An anti-lock braking system (ABS) is a safety anti-skid braking system used on aircraft and on land vehicles, such as cars, motorcycles, trucks, and buses. ABS operates by preventing the wheels from locking up during braking, thereby maintaini ...
* Anti-skid
Other features
* If one motor fails, the other motors are powerful enough to drive the vehicle to the nearest repair shop.
* Low maintenance.
* Easy replacement of motors.
* No
central gear box.
* No mechanical
differentials or
lockers.
* No long and heavy
drive shafts.
* On the spot, tank/wheelchair-like turning.
* On the fly switching between
FWD,
RWD and
AWD drive configurations.
The motors that are used in these vehicles are commonly
wheel hub 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 the hub of a wheel and drives it directly.
History
* First wheel motor concept: Wellington Adams of ...
s, since no transmission components are then required. Alternative layouts with inboard motors and drive shafts are also possible.
Hydraulic Wheel Drive
Hydraulic wheel drives share many of the same features as an electric wheel drive. They also lack the need for a central gear box, mechanical differentials, drive shafts, and provide on the fly switching between FWD, RWD, and AWD. Hydraulic individual wheel drives are standard in various machines, such as Zero Turn mowers, Multi One lifts / front end loaders, and forklifts. Hydraulic drives are primarily found in machines that serve uses which benefit from the ability to turn on a dime and move between forward and reverse modes without shifting gears, such as lawn mowers and loading equipment.
Although one may be conflicted in considering such systems as a direct drive system, being that a motorized pump must drive the hydraulic system from a position other than the wheel hub. Nonetheless the drive is provided directly from the hydraulic rotary motor found in or adjacent to the wheel hub.
See also
*
Direct-drive mechanism
A direct-drive mechanism is a mechanism design where the force or torque from a prime mover is transmitted directly to the effector device (such as the drive wheels of a vehicle) without involving any intermediate couplings such as a gear train or ...
References
{{Reflist
Car layouts