Shafts: Definition, Types, And Application

What is a Shaft?

A shaft is defined as a rotating machine element, usually circular in cross-section, which is used to transmit power from one part to another, or from a machine that produces power to a machine that absorbs power.

Shaft form the important element of machines. They support rotating parts like gears and pulleys and are themselves supported by bearings resting in the rigid machine housing.

The shafts perform the function of transmitting power from one rotating member to another supported by it or connected to it. Thus, they are subjected to torque due to power transmission and bending moment due to the reactions of the members that are supported by them.

Shafts are to be distinguished from axles which also support rotating members but do not transmit power.

Shafts are always made to circular cross-sections and could be either solid or hollow. The shafts are classifieds as straight, cranked, flexible, or articulated. Straight shafts are the commonest to be used for power transmission.

Such shafts are commonly designed as stepped cylindrical bars, that is, they have various diameters along their length, although constant diameter shafts would be easy to produce. The stepped shafts correspond to the magnitude of stress which varies along the length.

Moreover, the uniform diameter shafts are not compatible with assembly, disassembly, and maintenance such shafts would complicate the fastening of the parts fitted to them, particularly the bearings, which have restricted against sliding in an axial direction.

While determining the form of the stepped shaft it is borne in mind that the diameter of each cross-section should be such that each part fitted onto the shaft has convenient access to its seat.

A shaft is defined as a rotating machine element, usually circular in cross section, which is used to transmit power from one part to another, or from a machine which produces power to a machine which absorbs power.

The Material Used for the Shafts

The material used for ordinary shafts is mild steel. When high strength is required, alloy steel such as nickel, nickel-chromium, or chromium-vanadium steel is used. Shafts are generally formed by hot rolling and finished to size by cold drawing or turning and grinding.

The material used for the shafts must have the following properties:

  • It should have high strength.
  • It should have good mechanization.
  • It should have a low-notch sensitivity factor.
  • It should have good heat treatment properties.
  • It should have high wear-resistant properties.

The materials used for regular shafts are carbon steel of grade 40 C8, 45 C8, 50 C4, and 50 C12.

Manufacturing of Shafts

Shafts are usually produced by hot rolling and are prepared for shape by cold drawing or turning and grinding. Cold rolled shafts are stronger than hot-rolled shafts, but with higher residual stresses.

Residual stress can cause deformation of the shafts when it is mechanized, especially when slots or keys are cut. Shafts of larger diameter are usually forged and are shaped into a lathe.

Types of Shaft

Shafts are mainly classified into two types:

  • Transmission shafts are used to transmit power between the source and the machine absorbing power. e.g., countershafts, line shafts, and all factory shafts.
  • Machine shafts are an integral part of the machine itself. e.g., crankshaft
  • Axle shafts are used in vehicles.
  • A spindle shaft is a rotating shaft with a fixture for holding a tool or a workpiece.

Related: 1. What is Crankshaft? 2. What is Axle in a Car?

The Standard size of shafts are:

The standard sizes of transmission shafts are:

  • 25 mm to 60 mm with 5 mm steps
  • 60 mm to 110 mm with 10 mm steps
  • 110 mm to 140 mm with 15 mm steps and
  • 140 mm to 500 mm with 20 mm steps
  • The standard length of the shafts is 5 m, 6 m, and 7 m.

The standard sizes of Machine shafts are:

  • Up to 25 mm steps of 0.5 mm

Advantages of Shafts:

  • The shaft system is less likely to jam.
  • Less maintenance than a chain system when a tube is attached to the drive shaft.
  • A hollow shaft is a low weight than a solid shaft for the same torque transmission.
  • In the hollow shaft, the internal shape is hollow so the materials required are less.
  • The shaft is more strong and it has a low failure chance.
  • High polar moment of inertia
  • High torsional strength

Disadvantages of Shafts:

  • The power loss due to loose coupling.
  • Shafts can vibrate during rotation.
  • Produced a constant noise
  • Maintenance and manufacturing costs were high.
  • The manufacturing process is difficult.
  • The downtime was longer due to mechanical problems.
  • The use of flexible couplings, such as a leaf spring coupling, can cause a loss of velocity between shafts.
  • Changing the speed was not so easy.
  • Oil dripping from overhead shafting.

FAQs.

1. What is a Shaft?

A shaft is a rotating machine element with a long handle of a spear or similar weapon, usually circular in cross-section, which is used to transmit power from one rotating member to another supported by it or connected to it.

2. What are the types of Shafts?

Types of shafts:

  • Transmission shafts are used to transmit power between the source and the machine absorbing power. e.g., countershafts, line shafts, and all factory shafts.
  • Machine shafts are an integral part of the machine itself. e.g., crankshaft
  • Axle shafts are used in vehicles.
  • A spindle shaft is a rotating shaft with a fixture for holding tool or workpiece.

What is the definition of Shaft?

A shaft is defined as a rotating machine element, usually circular in cross-section, which is used to transmit power from one part to another, or from a machine that produces power to a machine that absorbs power.

What is a purpose of the mechanical shaft?

The term shaft usually refers to a component of a circular cross-section that rotates and transmits power from a driving device, such as a motor or engine, through a machine. Shafts can carry gears, pulleys, and sprockets to transmit rotary motion and power via mating gears, belts, and chains.

Why shafts are made circular?

Generally, for power transmission, circular shafts are used because there is uniform stress distribution along any radius of the shaft. Plane sections of shaft remain plane after the application of twisting moment, as a result, there is no distortion in the sections of shafts, and change in volume of the shaft is zero.

What type of steel is used for shafts?

The material used for ordinary shafts is carbon steel of grades 40 C 8, 45 C 8, 50 C 4, and 50 C 12. Shafts are generally manufactured by hot rolling and finished to size by cold drawing or turning and grinding.

What are transmission shafts?

The transmission shafts are a rotating machine part, generally of circular cross-section. That conveys power or motion from one part to another. In other words, it transmits power from the part which produces it to the one which absorbs. The transmission shaft is one of the crucial parts of all the rotating machinery.

How do shafts work?

The driveshaft is a spinning tube that transmits power from the engine to the back of the vehicle at the differential. It does this by transmitting the spinning power from front to back. The deliverance of torque from the transmission to differential then transmits torque to the wheels so the vehicle can move.

What are types of transmission shaft?

Types of Transmission Shafts

  • Input Shaft. The automobile’s engine crankshaft turns and creates power.
  • Counter Shaft. The counter shaft lies parallel to the main shaft and is driven by the input shaft through a pinion gear.
  • Output Shaft.
  • Other Configurations.

How shaft is manufactured?

The most common process used to manufacture shafts is via CNC turning. Using this technique, workers or automated processes affix or clamp bars of materials to chucks and rotate them. While rotating, specialized tools use cutting and other subtractive processes to create and shape the end product.

What are examples of shafts?

The definition of a shaft is a long, narrow handle or a long narrow part of something, a sudden bolt of light or a sudden flash of some feeling. The long narrow handle of a golf club is an example of a shaft. A long narrow mine shaft or a vertical elevator shaft are both examples of a shaft.

Can shafts be non-circular?

For non-circular shafts under torsion, the plane cross-sections perpendicular to the shaft axis do not remain plane after twisting, and deformation takes place in the axial direction which is called warping.

What is the maximum length of the shaft for mechanical use?

The standard lengths of the shafts are 5 m, 6 m and 7 m. Usually, 1m to 5m is used.

Can a shaft be rectangular?

A shaft was excavated to an oblong shape. The shape lends itself to equipping concurrently with sinking; it provides a convenient in-line hoisting arrangement and can easily be divided into separate compartments.

What shaft type should I use?

Which flex rating you use will depend on the type of swing you have. For example, beginners and those with less powerful swings tend to use a shaft with greater flexibility to propel the ball more. On the other hand, if a player has a high and powerful swing speed, they will require a stiffer shaft with less flex.

What is the hardest metal to machine?

In terms of tensile strength, tungsten is the strongest out of any natural metal (142,000 psi).

How many shafts are there in a car?

On a typical four-wheel drive or all-wheel drive vehicle, there are two driveshafts. There is the same driveshaft that is on a rear-wheel-drive car but there is also an additional front driveshaft that is connected to the front differential and the transfer case by u-joints.

How many propeller shafts are in a small car?

Small cars and short vans and trucks incorporate a single propeller shaft with a slip-joint at the front end without having any undesired vibration. Vehicles with longer wheelbase require a longer propeller shaft, which has a tendency to sag and to whirl under certain operating conditions.

How many shafts does a transmission have?

In terms of construction, manual transmissions contain two shafts; a primary shaft that is split into two parts/sections that can rotate independently of each other, and a secondary shaft that is made up of a series of fixed gears of various diameters.

Does shaft work negative?

Thus, the sign of shaft work is always negative, work being done on the system by the surroundings. Shaft work can hardly be done indefinitely slowly; consequently, it always produces entropy within the system, because it relies on friction or viscosity within the system for its transfer.

How is shaft power calculated?

The shaft power is calculated by dividing the hydraulic power by the pump efficiency.

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