Wikipedia

Drive shaft

Adrive shaft,driveshaft,driving shaft,tailshaft(Australian English),propeller shaft(prop shaft), orCardan shaft(afterGirolamo Cardano) is a component for transmitting mechanicalpower,torque,and rotation, usually used to connect other components of adrivetrainthat cannot be connected directly because of distance or the need to allow for relative movement between them.

Drive shaft withuniversal jointsat each end and asplinein the centre
3D animation of a Cardan shaft in a z-arrangement
Škoda422 rear axle, suspension and drive shaft on display at the Škoda Museum

As torque carriers, drive shafts are subject totorsionandshear stress,equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, while avoiding too much additional weight as that would in turn increase theirinertia.

To allow for variations in the alignment and distance between the driving and driven components, drive shafts frequently incorporate one or moreuniversal joints,jaw couplings,orrag joints,and sometimes asplined jointorprismatic joint.

History

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The termdriveshaftfirst appeared during the mid-19th century. In Stover's 1861 patent reissue for aplaning and matching machine,the term is used to refer to the belt-drivenshaftby which the machine is driven.[1]The term is not used in his original patent.[2]Another early use of the term occurs in the 1861 patent reissue for the Watkins and Bryson horse-drawnmowing machine.[3] Here, the term refers to the shaft transmitting power from the machine's wheels to the gear train that works the cutting mechanism.

In the 1890s, the term began to be used in a manner closer to the modern sense. In 1891, for example, Battles referred to the shaft between the transmission and drivingtrucksof hisClimax locomotiveas the drive shaft,[4]and Stillman referred to the shaft linking the crankshaft to the rear axle of hisshaft-driven bicycleas a drive shaft.[5]In 1899, Bukey used the term to describe the shaft transmitting power from the wheel to the driven machinery by auniversal jointin hisHorse-Power.[6]In the same year, Clark described his Marine Velocipede using the term to refer to the gear-driven shaft transmitting power through a universal joint to the propeller shaft.[7]Crompton used the term to refer to the shaft between the transmission of his steam-poweredMotor Vehicleof 1903 and the driven axle.[8]

The pioneering automobile industry company,Autocar,was the first to use a drive shaft in a gasoline-powered car.[9]Built in 1901, today this vehicle is in the collection of theSmithsonianInstitution.[10]

Automotive drive shaft

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Vehicles

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An automobile may use a longitudinal shaft to deliver power from an engine/transmission to the other end of the vehicle before it goes to the wheels. A pair of short drive shafts is commonly used to send power from a centraldifferential,transmission,ortransaxleto the wheels.

A truck two section propeller shaft

Front-engine, rear-wheel drive

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Main article:Front-engine, rear-wheel drive layout

Infront-engined, rear-wheel drivevehicles, a longer drive shaft is also required to send power the length of the vehicle. Two forms dominate: Thetorque tubewith a singleuniversal jointand the more commonHotchkiss drivewith two or more joints. This system became known asSystème Panhardafter the automobile companyPanhard et Levassorwhich patented it.

Most of these vehicles have aclutchandgearbox(or transmission) mounted directly on the engine, with a drive shaft leading to a final drive in the rear axle. When the vehicle is stationary, the drive shaft does not rotate. Some vehicles (generally sports cars, such as theChevrolet Corvette C5/C6/C7,Alfa Romeo AlfettaandPorsche 924/944/928), seeking improved weight balance between front and rear, use a rear-mountedtransaxle.In some non-Porsche models, this places the clutch and transmission at therearof the car and the drive shaft between them and the engine. In this case the drive shaft rotates continuously with the engine, even when the car is stationary and out of gear. However, the Porsche 924/944/928 models have the clutch mounted to the back of the engine in a bell housing and the drive shaft from the clutch output, located inside of a hollow protective torque tube, transfers power to the rear mounted transaxle (transmission + differential). Thus the Porsche driveshaft only rotates when the rear wheels are turning as the engine-mounted clutch can decouple engine crankshaft rotation from the driveshaft. So for Porsche, when the driver is using the clutch while briskly shifting up or down (manual transmission), the engine can rev freely with the driver's accelerator pedal input, since with the clutch disengaged, the engine and flywheel inertia is relatively low and is not burdened with the added rotational inertia of the driveshaft. The Porsche torque tube is solidly fastened to both the engine's bell housing and to the transaxle case, fi xing the length and alignment between the bell housing and the transaxle and greatly minimizing rear wheel drive reaction torque from twisting the transaxle in any plane.

A drive shaft connecting a rear differential to a rear wheel may be called a half-shaft. The name derives from the fact that two such shafts are required to form onerear axle.

Early automobiles often usedchain driveorbelt drivemechanisms rather than a drive shaft. Some used electrical generators and motors to transmit power to the wheels.

Front-wheel drive

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InBritish English,the termdrive shaftis restricted to a transverse shaft that transmits power to the wheels, especially the front wheels. The shaft connecting the gearbox to a rear differential is called a "propeller shaft", or "prop-shaft". A prop-shaft assembly consists of a propeller shaft, aslip jointand one or more universal joints. Where the engine and axles are separated from each other, as onfour-wheel driveandrear-wheel drivevehicles, it is the propeller shaft that serves to transmit the drive force generated by the engine to the axles.

Several different types of drive shaft are used in the automotive industry:

  • One-piece drive shaft
  • Two-piece drive shaft
  • Slip-in-tube drive shaft

The slip-in-tube drive shaft is a new type that improves crash safety. It can be compressed to absorb energy in the event of a crash, so is also known as a "collapsible drive shaft".

Four wheel and all-wheel drive

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These evolved from the front-engine rear-wheel drive layout. A new form of transmission called thetransfer casewas placed between transmission and final drives in both axles. This split the drive to the two axles and may also have included reduction gears, a dog clutch or differential. At least two drive shafts were used, one from the transfer case to each axle. In some larger vehicles, the transfer box was centrally mounted and was itself driven by a short drive shaft. In vehicles the size of aLand Rover,the drive shaft to the front axle is noticeably shorter and more steeply articulated than the rear shaft, making it a more difficult engineering problem to build a reliable drive shaft, and which may involve a more sophisticated form of universal joint.

Modern light cars withall-wheel drive(notablyAudior theFiat Panda) may use a system that more closely resembles a front-wheel drive layout. The transmission and final drive for the front axle are combined into one housing alongside the engine, and a single drive shaft runs the length of the car to the rear axle. This is a favoured design where the torque is biased to the front wheels to give car-like handling, or where the maker wishes to produce both four-wheel drive and front-wheel drive cars with many shared components.

Research and development

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The automotive industry also uses drive shafts at testing plants.

At anengine test stand,a drive shaft is used to transfer a certain speed or torque from theinternal combustion engineto adynamometer.

A "shaft guard" is used at a shaft connection to protect against contact with the drive shaft and for detection of a shaft failure.

At a transmission test stand a drive shaft connects the prime mover with the transmission.

Symptoms of a bad drive shaft

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An automotive drive shaft can typically last about 120,000 kilometres. However, if the vehicle experiencing any of the signs below, drivers should get it checked as soon as possible.[11]

  • Clicking or squeaking noise: Driver can either hear a clicking, squeaking, or grinding noises coming from underneath the vehicle when driving.
  • Clunking sounds: Driver can hear the noises especially when turning the vehicle, accelerating or even putting it into reverse.
  • Vibration: An early and common symptom of a failing drive shaft is an intense vibration coming from underneath the vehicle. Worn out couplings, u-joints, or bearings cause excessive drive shaft vibration.
  • Turning problems: Problems with turning the vehicle, both during slow and high-speed drives, is another significant sign of a bad drive shaft.

Cardan shaft park brakes

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A cardan shaft park brake works on the drive shaft rather than the wheels.[12]These brakes are commonly used on small trucks. This type of brake is prone to failure and has led to incidents where the truck has run away on a slope, leading to safety alerts being issued.[13]Heavy vehicles that have this type of park brake usually have a ratchet handle similar to a car'shand brake or parking brake,as opposed to anair brakebutton or lever.

Risk factors for drivers include parking on a steep slope when heavily loaded, not applying the brake with enough force, changing the load or load balance while parked on a slope, or parking where one side of the vehicle is able to slip. Usingchockson the wheels is one way of preventing the vehicle from moving on a slope.

Motorcycle drive shafts

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The exposed drive shaft on BMW's first motorcycle, theR32

Drive shafts have been used onmotorcyclessince before WW1, such as the BelgianFN motorcyclefrom 1903 and theStuart TurnerStellar motorcycle of 1912. As an alternative tochainandbeltdrives, drive shafts offer long-lived, clean, and relatively maintenance-free operation. A disadvantage of shaft drive on a motorcycle is thathelical gearing,spiral bevel gearingor similar is needed to turn the power 90° from the shaft to the rear wheel, losing some power in the process.

BMWhas produced shaft drive motorcycles since 1923; andMoto Guzzihave built shaft-driveV-twinssince the 1960s. The British company,Triumphand the major Japanese brands,Honda,Suzuki,KawasakiandYamaha,have produced shaft drive motorcycles.

Lambrettamotorscooters type A up to type LD are shaft-driven[14]the NSU Prima scooter is also shaft-driven[15]

Motorcycle engines positioned such that thecrankshaft is longitudinal and parallel to the frameare often used for shaft-driven motorcycles. This requires only one 90° turn in power transmission, rather than two. Bikes from Moto Guzzi and BMW, plus theTriumph Rocket IIIandHonda ST seriesall use this engine layout.

Motorcycles with shaft drive are subject toshaft effect,where the chassis climbs when power is applied. This effect, which is the opposite of that exhibited by chain-drive motorcycles, is counteracted with systems such as BMW'sParalever,Moto Guzzi'sCARCand Kawasaki'sTetra Lever.

Marine drive shafts

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The drive shaft of a freight ship,Cap San Diego

On a power-driven ship, the drive shaft, or propeller shaft, usually connects thepropelleroutside the vessel to the driving machinery inside, passing through at least one shaft seal orstuffing boxwhere it intersects thehull.The thrust, the axial force generated by the propeller, is transmitted to the vessel by thethrust blockor thrust bearing, which, in all but the smallest of boats, is incorporated in the main engine or gearbox. Shafts can be made of stainless steel[16]or composite[17]materials depending on what type of ship will install them.

The portion of the drive train which connects directly to the propeller is known as thetail shaft.[18]

Locomotive drive shafts

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The rear drive shaft, crankshaft and front drive shaft of aShay locomotive

TheShay,ClimaxandHeislerlocomotives, all introduced in the late 19th century, usedquill drivesto couple power from a centrally mounted multi-cylinder engine to each of thetruckssupporting the engine. On each of thesegeared steam locomotives,one end of each drive shaft was coupled to the driven truck through auniversal jointwhile the other end was powered by thecrankshaft,transmissionor another truck through a second universal joint. A quill drive also has the ability to slide lengthways, effectively varying its length. This is required to allow the bogies to rotate when passing a curve.

Cardan shafts are used in somediesel locomotives(mainly diesel-hydraulics, such asBritish Rail Class 52) and someelectric locomotives(e.g.British Rail Class 91). They are also widely used indiesel multiple units.

Drive shafts in bicycles

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Main article:shaft-driven bicycle
Ashaft-driven bicycle

The drive shaft has served as an alternative to a chain-drive inbicyclesfor the past century, never becoming very popular. Ashaft-driven bicycle(or "Acatène", from an early maker) has several advantages and disadvantages:

Advantages

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  • Drive system is less likely to become jammed.
  • The rider cannot become dirtied from chain grease or injured by "chain bite" when clothing or a body part catches between anunguarded chainand a sprocket.
  • Lower maintenance than a chain system when the drive shaft is enclosed in a tube.
  • More consistent performance. Dynamic Bicycles claims that a drive shaft bicycle can deliver 94% efficiency, whereas a chain-driven bike can deliver anywhere from 75 to 97% efficiency based on condition.

Disadvantages

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  • A drive shaft system weighs more than a chain system, usually 0.5–1 kg (1–2 lb) heavier.
  • Many of the advantages claimed by drive shaft's proponents can be achieved on a chain-driven bicycle, such ascovering the chain and sprockets.
  • Use of lightweightderailleurgears with a high number of ratios is impossible, althoughhub gearscan be used.
  • Wheel removal can be complicated in some designs (as it is for some chain-driven bicycles with hub gears).

PTO drive shafts

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Main article:Power take-off

Drive shafts are one method of transferring power from an engine andPTOto vehicle-mounted accessory equipment, such as anair compressor.Drive shafts are used when there is not enough space beside the engine for the additional accessory; the shaft bridges the gap between the engine PTO and the accessory, allowing the accessory to be mounted elsewhere on the vehicle.[19]

Drive shaft production

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Nowadays new possibilities exist for the production process of drive shafts. Thefilament windingproduction process is gaining popularity for the creation ofcompositedrive shafts. Several companies in the automotive industry are looking to adopt this knowledge for their high volume production process.[citation needed]

See also

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Wikimedia Commons has media related toDriveshafts.

References

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  1. ^Henry D. Stover, Improvement in Wood-Planing Machines,U.S. Patent Reissue 1,190,May 21, 1861.
  2. ^Henry D. Stover, Planing Machine,U.S. Patent 30,993,December 18, 1860, 1861.
  3. ^John DeLancy Watkins and Robert Bryson, Mowing Machines,U.S. Patent Reissue 1,904,July 23, 1861.
  4. ^Rush S. Battles, Locomotive,U.S. Patent 455,154,June 30, 1891.
  5. ^Walter Stillman, Bicycle,U.S. Patent 456,387,July 21, 1891.
  6. ^Dudley D. Bukey, Horse-Power,U.S. Patent 631,198,August 15, 1899.
  7. ^Charles Clark, Marine Velocipede, [U.S. Patent 637,547], November 21, 1899.
  8. ^Charles Crompton, Motor-VehicleU.S. Patent 718,097,January 1903
  9. ^"Autocar, 1901".
  10. ^"Autocar automobile".National Museum of American History. November 2, 2016.RetrievedNovember 19,2017.
  11. ^"Drive Shaft — The Definitive Guide 2021".Saiko.Malaysia.RetrievedSeptember 10,2021.
  12. ^"What is a cardan shaft brake and why do they fail".Driving Tests Resources.November 10, 2022.RetrievedNovember 14,2022.
  13. ^"Driveshaft parking brake failures in commercial and industrial vehicles".WorkSafe.RetrievedNovember 14,2022.
  14. ^"Lambretta Scooters Models".Cambridge Lambretta Workshop.UK.RetrievedAugust 26,2016.
  15. ^"NSU Prima sales brochures".NSU Prima.RetrievedAugust 26,2016.
  16. ^"BT Marine Propellers - Propeller shafts".btmarinepropellers.co.uk.RetrievedMarch 28,2021.
  17. ^"Composite Shafting".vulkan.RetrievedMarch 28,2021.
  18. ^"Wärtsilä Encyclopedia of Marine Technology".
  19. ^"What Is A PTO Driven Air Compressor?".VMAC.March 15, 2019.RetrievedMarch 25,2019.
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