A drive shaft
, or propeller shaft is a shaft that transmits the power from the machinery inside the vessel to the external propeller. It passes through a number of seals and bearings, to avoid water entering and damaging the driving machinery. It is also subject to a large amount of shear stress, the equivalent of the difference between the applied torque and the load, and thus requires considerable strength to prevent failure.
Most cars and other vehicles use a drive shaft to transfer engine power to the wheels. In front wheel drive cars the driveshafts are between the transmission and each of the front wheels, while in rear wheel drive or four-wheel-drive cars they run the length of the car between the differential up front and the back wheels.
The main function of the drive shaft is to carry engine torque to the wheels, while compensating for all variations in angle or length resulting from manoeuvring and deflection for perfect synchronisation between joints. To achieve this they are often constructed as a hollow steel tube with yokes welded on to take the wheels, gears and pulleys. They can be reinforced by one or more rings and are often fitted with universal joints, jaw couplings, rag joints, splined joints and sometimes prismatic joints, in order to withstand the high amounts of shear stress they encounter.
Drive shafts are used in many applications, not just in cars, but also in locomotives, marine vessels, aircraft and a range of other equipment that uses a mechanical drive. The shafts are normally made from stainless steel, although aluminium and bronze can be used if desired for lighter weight or corrosion resistance.
In early automobiles it was common to use belt mechanisms to carry the power from the engine to the wheels, but this would have been very difficult to do while steering the vehicle, and road surfaces are not perfectly smooth! Drive shafts were therefore developed, and they remain an integral part of the modern automotive system.
When a driveshaft fails, it can cause your car to shake underneath you. This can be caused by a variety of reasons, such as a worn out u-joint or coupler. If left unchecked, the problem can spread to other components of the drivetrain and may even cause a breakdown of the entire car.
The best way to ensure that your drive shaft is in good condition is to have it regularly inspected by an auto repair professional. This will help to prevent issues from arising, and it will allow you to be aware of when a problem occurs so that you can get it checked or repaired as quickly as possible. Putting off a repairs to the drive shaft can cause damage to other components of your car, such as the clutch, so it is important to have them done as soon as you notice any signs of wear or tear.