Axle

Information about Axle

Train wheels are affixed to a straight axle, such that both wheels rotate in unison.

An axle is a central shaft for a rotating wheel or gear. In some cases the axle may be fixed in position with a bearing or bushing sitting inside the hole in the wheel or gear to allow the wheel or gear to rotate around the axle. In other cases the wheel or gear may be fixed to the axle, with bearings or bushings provided at the mounting points where the axle is supported. Sometimes, especially on bicycles, the latter type is referred to as a spindle.

Vehicle axles

Axles are an integral structural component of a wheeled vehicle. The axles maintain the position of the wheels relative to each other and to the vehicle body. Since for most vehicles the wheels are the only part touching the ground, the axles must bear the weight of the vehicle plus any cargo, and also any acceleration forces between the vehicle and the ground. In addition to the structural purpose, axles may serve one or more of the following purposes depending on the design of the vehicle.

Drive
One or more axles may be an integral part of the drivetrain. A mechanical system (typically a motor) exerts a rotational force on the axle, which is transferred to the wheel(s) to accelerate the vehicle.
Braking
Conversely a vehicle may be slowed by applying force to brake the rotation of the axle. Consumer vehicles' brakes are part of the wheel assembly and therefore exert friction on the wheels directly, but engine braking may still be effected via the axle.
Steering
The front axle of most automobiles is a steering axle. The vehicle is maneuvered by controlling the direction of the front wheels' rotational axis relative to the body and rear wheels.

Structural features

0 Series Shinkansen Wheel

A straight axle is a single rigid shaft connecting a wheel on the left side of the vehicle to a wheel on the right side. The axis of rotation fixed by the axle is common to both wheels. Such a design can keep the wheel positions steady under heavy stress, and can therefore support heavy loads. Straight axles are used on trains, for the rear axles of commercial trucks, and on heavy duty off-road vehicles. The axle can be protected and further reinforced by enclosing the length of the axle in a housing.

In a split axle design, the wheel on each side is attached to a separate shaft. Modern passenger cars generally have split front and rear axles. This allows independent suspension of the left and right wheels, and therefore a smoother ride. It also permits the left and right wheels to rotate at different speeds as the automobile turns, improving traction and extending tire life.

A tandem axle is a group of two or more axles situated close together. Trucks designs will use such a configuration to provide a greater weight capacity than a single axle. Semi trailers usually have a tandem axle at the rear.

Drive axles

See also:

An axle that is driven by the engine is called a drive axle.

Modern front wheel drive cars typically combine the transmission and front axle into a single unit called a transaxle. The drive axle is a split axle with a differential and universal joints between the two half axles. Each half axle connects to the wheel by use of a constant velocity (CV) joint which allows the wheel assembly to move freely vertically as well as to pivot when making turns.

In rear wheel drive cars and trucks, the engine turns a driveshaft which transmits rotational force to a drive axle at the rear of the vehicle. The drive axle may be a live axle, but modern automobiles generally use a split axle with a differential.

Some simple vehicle designs, such as go-karts, may have a single drive wheel. The drive axle is a split axle with only one of the two shafts driven by the engine.

Dead axles/lazy axles

This dump truck has an airlift pusher axle, shown in the raised position.

A dead axle, also called lazy axle, is not part of the drivetrain but is instead free-rotating. The rear axle of a front-wheel drive car may be considered a dead axle. Many trucks and trailers use dead axles for strictly load-bearing purposes. A dead axle located immediately in front of a drive axle is called a pusher axle. A tag axle is a dead axle situated behind a drive axle.

Some dump trucks and trailers are configured with airlift axles, which may be mechanically raised or lowered. The axle is lowered to increase the weight capacity, or to distribute the weight of the cargo over more wheels, for example to cross a weight restricted bridge. When not needed, the axle is lifted off the ground, to save wear on the tires and axle and increase traction in the remaining wheels. Lifting an axle also makes the vehicle tighten turns better.

Several manufacturers offer computer-controlled airlift, so that the dead axles are automacally lowered when the main axle reaches its weight limit. The axles can still be lifted by the press of a button if needed.

Patents

U.S. Patent 772,571 , D. Balachowsky and P Caire, Driving Axle

This article is about rotation as a movement of a physical body. For other uses, see Rotation (disambiguation).

A rotation is a movement of an object in a circular motion.
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wheel is a circular device capable of rotating on its axis, facilitating movement or transportation or performing labour in machines. A wheel together with an axle overcomes friction by facilitating motion by rolling. Common examples are found in transport applications.
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A gear is a component within a transmission device that transmits rotational force to another gear or device. A gear is different from a pulley in that a gear is a round wheel which has linkages ("teeth" or "cogs") that mesh with other gear teeth, allowing force to be fully
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A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation.
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bushing is a cylindrical lining designed to reduce friction and wear, or constrict and restrain motion of mechanical parts.

In the electrical field bushings are circular plastic ring fittings that slide or screw onto conduit or connectors to provide protection to the
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racing bicycle is built using lightweight, shaped aluminium tubing and carbon fiber stays and forks. It sports a drop handlebar and thin tires and wheels for efficiency and aerodynamics.
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Spindle may refer to:

In technology

A spindle, also called cakebox, is the a type of optical disc packaging, the plastic container in which bulk blank CDs and DVDs are often sold
A spindle is the axis on which the platters of a computer hard disk spin.

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Vehicles are non-living means of transport. They are most often man-made (e.g. bicycles, cars, motorcycles, trains, ships, and aircraft), although some other means of transport which are not made by man can also be called vehicles; examples include icebergs and floating tree trunks.
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Cargo is a term used to denote goods or produce being transported generally for commercial gain, usually on a ship, plane, train, van or truck. Nowadays containers are used in most intermodal long-haul cargo transport.

Cargo represents a concern to U.S. national security.
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For the album by .38 Special, see .

In a vehicle, the term drivetrain or powertrain refers to the group of components that generate power and deliver it to the road surface, water, or air.
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For the album by .38 Special, see .

electric motor converts electrical energy into mechanical energy. The reverse process, that of converting mechanical energy into electrical energy, is accomplished by a generator or dynamo.
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brake is a device for slowing or stopping the motion of a machine or vehicle, or alternatively a device to restrain it from starting to move again. The kinetic energy lost by the moving part is usually translated to heat by friction.
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Engine braking is the act of using the energy-requiring compression stroke of the internal combustion engine to dissipate energy and slow down a vehicle. Compression braking is a common legal term for the same mechanism.
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Steering is the term applied to the collection of components, linkages, etc. which will allow for a vessel (ship, boat) or vehicle (car) to follow the desired course. An exception is the case of rail transport by which rail tracks combined together with railroad switches provide
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automobile (from Greek auto, self and Latin mobile moving, a vehicle that moves itself rather than being moved by another vehicle or animal) or motor car (usually shortened to just car) is a wheeled passenger vehicle that carries its own motor.
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train is a series of rail vehicles that move along guides to transport freight or passengers from one place to another. The guideway (permanent way) usually consists of conventional rail tracks, but might also be monorail or maglev.
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truck is a vehicle usually used for transporting bulk goods, materials, or equipment. The word "truck" comes from the Greek "trochos", meaning "wheel". In America, the big wheels of wagons were called trucks.
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Off Roading is a term for driving a specialized vehicle on unpaved roads, such as sand, gravel, riverbeds, mud, snow, rocks and other natural terrain.

Off-road vehicle

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Independent suspension is a broad term for any automobile suspension system that allows each wheel on the same axle to move vertically (i.e. reacting to a bump in the road) independently of each other.
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semi-trailer is a trailer without a front axle. A large proportion of its weight is supported either by a road tractor or by a detachable front axle assembly known as a dolly. A semi-trailer is normally equipped with legs which can be lowered to support it when it is uncoupled.
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Front-wheel drive is a form of engine/transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in
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range of input/output ratios in addition to its infinite number of possible ratios; this qualification for the IVT implies that its range of ratios includes a zero output/input ratio that can be continuously approached from a defined 'higher' ratio.
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A transaxle, in the automotive field, is a component that combines the functionality of the transmission, the differential and the drive axle into one integrated assembly.
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differential is a device, usually consisting of gears, that allows each of the driving wheels to rotate at different speeds, while supplying equal torque to each of them.

Purpose

A vehicle's wheels rotate at different speeds, especially when turning corners.
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A universal joint, U joint, Cardan joint, Hardy-Spicer joint, or Hooke's joint is a joint in a rigid rod that allows the rod to 'bend' in any direction.
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Constant Velocity Joints (aka homokinetic or CV joints) allow a rotating shaft to transmit power through a variable angle, at constant rotational speed, without an appreciable increase in friction or play.
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Layouts: FF, FMR, FR, MF, RMR, RR, F4, M4, R4
Engine positioning: Front-engine, Mid-engine, Rear-engine
Drive: Front-wheel drive, Rear-wheel drive, Four-wheel drive, Six-wheel drive
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A live axle is a type of beam axle suspension system that uses the driveshafts that transmit power to the wheels to connect the wheels laterally so that they move together as a unit.
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Kart racing or karting is a variant of open-wheeler motor sport with simple, small four-wheeled vehicles called karts, go-karts, or gearbox/shifter karts depending on the design. They are usually raced on scaled-down circuits.
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