# Mechatronics Questions and Answers – Mechanical Actuating Systems – Bearings

This set of Mechatronics Multiple Choice Questions & Answers (MCQs) focuses on “Mechanical Actuating Systems – Bearings”.

1. Who patented the first ball bearing?
a) Grueblerowen
b) Vitaly Abalakov
c) Philip Vaughan
d) Robert Abalakov

Explanation: Philip Vaughan patented the first ball bearing. He was an iron master and welsh inventor who designed the first ball bearing in the year 1794 at Carmarthen. His design was the first modern design that depicted the balls running along the groove in axle assembly.

2. What is the principle behind the working of magnetic bearing?
a) Maxwell’s second law
b) Electromagnetic suspension
c) Lenz law
d) Flemings Right hand thumb rule

Explanation: The principle behind the working of magnetic bearing is Electromagnetic suspension. It is based on the electromagnetic induction of eddy current in rotating conductor. It has no physical moving part inside it and is able to achieve very high speeds.

3. Which bearing is also called as thrust bearing?
b) Axial bearing
c) Tangential bearing
d) Snail drop bearing

Explanation: Axial bearing is also called as thrust bearing. These bearings are often designed to resist the force in the same direction as of the shaft. And these loads are called as axial loads or thrust loads.

4. Which type of bearing can achieve highest speed?
a) Ball bearing
b) Roller bearing
c) Magnetic bearing
d) Tapered roller bearings

Explanation: Magnetic bearing can achieve highest speed. These bearings can revolve at very high speed of around 50,000 to 60,000 rpm (revolution per minute) without getting damaged. It is so because it has no moving part inside it. It works on the principle of electromagnetic suspension. Normal ball or roller bearing cannot achieve this speed without getting damaged.

5. Radial ball bearing is also called as roller bearing.
a) True
b) False

Explanation: Roller bearing and radial ball bearings are not same. They are two different types of bearing that have different inbuilt mechanism. Ball bearings use metallic balls between the inner and outer races whereas roller bearings use cylindrical rods between the races.
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6. Slot fill type ball bearings have higher load bearing capacity than Conrad type ball bearing.
a) True
b) False

Explanation: Slot fill type ball bearings have higher load bearing capacity than Conrad type ball bearing. It is so because notches are present on the inner and outer surfaces of outer and inner race respectively. This facilitates more balls more ball to fit in the same amount of space which increases the load bearing capacity.

7. Which type of bearing has axial length at least 4 times the length of the diameter?
a) Tapered roller bearing
b) Needle roller bearing
c) Thrust ball bearing
d) Thrust roller bearing

Explanation: Needle roller bearing has axial length at least 4 times the length of the diameter. These bearings have extremely small diameters. The rollers or the cylindrical rods used in it resemble a needle which is why it is known as needle roller bearing.

8. Which type of bearing has a frustum shape assembly?
a) Tapered roller bearing
b) Needle roller bearing
c) Thrust ball bearing
d) Thrust roller bearing

Explanation: Tapered roller bearing has a frustum shape assembly. It is often termed as cup and cone assembly. Its shape resembles the shape of a frustum. These bearings can bear high axial and radial loads but provides moderate revolution speed.

9. Who invented Conrad style ball bearing?
a) Grueblerowen
c) Philip Vaughan

Explanation: Robert Conrad invented Conrad style ball bearing. These bearings are named after the inventor. These bearing are most familiar and most common type ball bearing used in most of the day to day appliances. They can withstand both radial and axial loads.

10. Which type of bearing has a frustum of a cone shaped roller inside it?
a) Tapered roller bearing
b) Needle roller bearing
c) Thrust ball bearing
d) Thrust roller bearing

Explanation: Tapered roller bearing has a frustum of a cone shaped roller inside it. These rollers are also referred as taper rollers. These bearings can bear high axial and radial loads but provides moderate revolution speed.

11. Single row deep groove ball bearing can bear more radial load than double row deep groove ball bearing.
a) True
b) False

Explanation: Single row deep groove ball bearing cannot bear more radial load than double row deep groove ball bearing. Double row bearing can bear more radial load as well as axial load than single row bearing. Single row deep groove bearing can provide higher speed than double row ball bearing as it experiences lesser frictional force.

12. Ball bearing is preferred over roller bearings when the bearing has to bear huge load.
a) True
b) False

Explanation: Ball bearing is not preferred over roller bearing when the bearing has to bear huge load. Rather roller bearings are preferred for these kinds of application. It is so because roller bearings have larger area of contact than ball bearings which helps in easy distribution of load throughout the bearing.

13. Ball bearings provide higher rotational speed than roller bearing of same size.
a) True
b) False

Explanation: Ball bearings provide higher rotational speed than roller bearing of same size. It is so because Ball bearings have lesser area of contact than roller bearings. Therefore it experiences lesser frictional force than roller bearings which helps ball bearings to achieve higher speed.

14. When was the first ball bearing patented?
a) 1792
b) 1794
c) 1892
d) 1894

Explanation: The first ball bearing was patented in the year 1794. Philip Vaughan was the first who was awarded with the first patent of modern ball bearing. He was an iron master and welsh inventor whose design depicted the balls running along the groove in axle assembly.

15. Which type of bearing has no moving parts inside it?
a) Ball bearing
b) Roller bearing
c) Magnetic bearing
d) Tapered roller bearings

Explanation: Magnetic bearing has no moving parts inside it. These bearings can revolve at very high speed of around 50,000 to 60,000 rpm (revolution per minute) without getting damaged. Normal ball or roller bearing cannot achieve this speed without getting damaged.

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