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Hollow Shaft: Characteristics, Advantages, and Disadvantages
By BYJU'S Exam Prep
Updated on: September 25th, 2023
In all their specialized varieties and designs, Shafts are among the most fundamental mechanical engineering components. Their capacity to conduct torque and support rotating elements makes them indispensable in almost any sort of machine. A shaft resembles an elongated rod or bar in appearance and is manufactured in a variety of sizes. The material used to make it is first and foremost chosen to suit the intended use and the demands it must meet in usage. Different types of structural steel meet fundamental requirements such as material strength, hardenability, and ductility.
Furthermore, hardened and tempered or case-hardening steels are commonly utilized in applications where the shaft must bear high loads and meet additional requirements. The Hollow shaft is an alternate construction with the same qualities as the standard type in structure and function. However, unlike a conventional solid shaft, the fact that it is hollow confers a number of advantages that make this form of shaft a popular and common component of many sorts of machines.
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What is Hollow Shaft?
The hollow drive shaft connected to electric motors or right-angle gear drives to accommodate the solid shaft of the pump is known as a hollow shaft. The hollow shaft allows for impeller adjustment within the bowl assembly and the installation of a non-reverse ratchet in the motor or gear drive.
The rigidity of a hollow shaft is greater than that of a solid shaft of the same weight. Hollow shafts and concepts related to them are seen in the GATE exam. The material at the center of the hollow shaft is removed and dispersed out at a great radius. As a result, hollow shafts are stronger than solid shafts of the same weight.
Characteristics and Benefits of Hollow Shaft
The fundamental benefit of the hollow shaft’s distinctive construction is its huge weight savings, which is useful not only for engineering but also for functional ones. Another advantage of the hollow is that it saves space because operating resources, media, or even mechanical elements such as axles and shafts can be accommodated in it or use the workspace as a channel. The design of shafts that are hollow is a bit complex. Furthermore, hollow shafts have a relatively high resonance frequency.
The hollow shaft is an important component of the hollow shaft motor, utilized in electrically powered vehicles like trains. Hollow shafts can also be used to build jigs and fixtures and automatic machines.
Difference between the Hollow Shaft and Solid Shaft
Suppose a hollow and a solid shaft are the same weight. In that case, the hollow shaft includes the same amount of material at the ends. The solid shaft distributes the material uniformly throughout the shaft, leaving little material at the ends. These differences can be used in the MSQ based questions in the GATE ME question paper. Resistance to bending and resistance to torsion distinguishes them from one another. Following are the difference between a hollow and solid shaft in extensive detail.
- Because the material at the center of the hollow shaft is removed and spread at a vast radius, hollow shafts are stronger than solid shafts of the same weight.
- The rigidity of a hollow shaft is greater than that of a solid shaft of the same weight.
- The hollow shaft is stronger than the solid shaft of the same weight.
- The hollow shaft has a greater natural frequency than a solid shaft of the same weight.
- A hollow shaft is more expensive than a solid shaft.
- The diameter of a hollow shaft is greater than that of a solid shaft, requiring more space.
- Hollow shafts have a higher polar moment of inertia than solid shafts, allowing them to transmit greater torque.
- Although hollow shafts do not convey more power, their power-to-weight ratio is greater than that of solid shafts.
- When subjected to bending, solid shafts are stronger than hollow shafts.
Advantages of Hollow Shaft
Hollow shafts are significantly lighter than solid shafts and can transmit the same torque as solid shafts of equal diameters. Furthermore, hollow shafts require less energy to accelerate and decelerate. As a result, hollow shafts have a lot of potential in the automotive industry for power transmission. Following are the advantages of hollow shafts over solid shafts.
- It is lighter than a solid shaft of the same diameter.
- The rotational inertia is low.
- Less expensive.
- Due to the low weight, there is a high tolerance to rotational unbalance.
- Because of their low specific mass, hollow shafts are also resistant to high temperatures.
Disadvantage of Hollow Shaft
Hollow shafts have less torsional rigidity than solid shafts, making them more prone to torsion and torque non-transmission. Following are the disadvantages of hollow shafts over solid shafts.
- Less tolerant of excessive torque.
- Bending prone, especially when subjected to lateral tension.
- Such as a boat propeller shaft.
- It is tolerant of mild imbalance, but this increases as rotational speed exceed the critical limit.
Differences between a Shaft and an Axle
Although the terms shaft and axle are frequently used interchangeably in daily English, they have distinct features in the context of machinery pieces, notably in terms of functionality. Axles, unlike shafts, do not transmit torque but rather support rotating or oscillating elements. The primary function of any axle is to serve as a bearing for rotating mechanical components. They are often installed in the machine frame and are frequently subjected to high-stress levels due to cross forces and bending moments.
