Shafts

Question 1

What are the primary objectives in studying shafts?

Answer 1

Understanding shaft loading in operation, methods to join two shafts, and ways to attach elements like gears or pulleys to a shaft.

Question 2

How are shafts primarily used in machinery?

Answer 2

They are used for transmitting power through a machine and are often connected together via gears, belts, or chains.

Question 3

What are the common methods of connecting shafts?

Answer 3

Shaft connections can be made using chain drives, gear drives, or belt drives.

Question 4

Describe a plain shaft in shaft design.

Answer 4

A plain shaft is designed with a shoulder to prevent axial movement.

Question 5

What are typical reactions at bearings in shaft loading?

Answer 5

Shafts experience torque reactions at bearings due to driven elements like propellers or helical gears.

Question 6

What is the function of shaft couplings?

Answer 6

haft couplings are used to join separate shafts together and can compensate for misalignment while absorbing shock and vibration.

Question 7

What is the role of axial movement in shaft joining?

Answer 7

Axial movement is a consideration in shaft misalignment, especially due to thermal expansion.

Question 8

What are the two main ways to join shafts?

Answer 8

The two ways are rigid couplings and flexible couplings.

Question 8

What are the two types of shaft misalignment?

Answer 8

Parallel misalignment (shaft axes offset) and angular misalignment (shaft axes rotated).

Question 9

Describe rigid couplings in shaft joining.

Answer 9

Rigid couplings join two shafts as if they were one, requiring good alignment, and are used in high speed and load applications.

Question 10

What are the characteristics of flexible couplings?

Answer 10

Flexible couplings join shafts while allowing for some misalignment. They come in two types: kinematic flexibility (rigid components) and resilient flexibility (flexible components).

Question 11

What are the typical elements connected to shafts?

Answer 11

Common elements include pulleys, gears, propellers, and flywheels.

Question 12

What are the two ways to make connections to shafts?

Answer 12

Connections can be made through positive drive connections and friction drive connections.

Question 13

Describe positive drive connections for shafts.

Answer 13

These include using pins (cylindrical, taper, roll) and keys (plain, taper, gib head, woodruff) which provide rotational restraint and, in some cases, axial restraint.

Question 14

What are splines in the context of shaft connections?

Answer 14

Splines are axial ribs machined onto a shaft, offering a stronger alternative to keys, with the load shared over all ribs.

Question 15

Explain friction drive connections in shafts.

Answer 15

These connections transmit torque via friction between the hub and shaft, often involving clamping, interference fit, or tapered fit.

Question 16

What determines the maximum torque in a friction drive connection?

Answer 16

The maximum torque is influenced by the coefficient of friction between shaft and hub, clamping pressure, and the shaft-hub interface area.

Question 17

Summarize the key points about shafts from the lecture.

Answer 17

Shafts are dynamically loaded and prone to fatigue failure, can be joined together using rigid or flexible couplings, and have elements connected through positive or friction drive connections.

Question 17

How does a Trantorque bush work?

Answer 17

This proprietary device offers advantages like no requirement for accurate machining, no stress concentration, easy dismantling, and axial restraint.

Question 18

Describe the types of tapered connections in friction drive.

Answer 18

Types include clamped connections, interference fit connections, and tapered surface connections.