1. Topics Introduction Shaft Design Stresses and Loads on Shafts
Shaft Fits
Shaft Locking Devices
Exercise Questions
Note: Refer to Chapter 7 in the text.

2. Introduction
Shafts are used to transmit mechanical power such as the propeller shafts in vehicles.
Applications of shafts:
- To transmit power
- To extend other shafts
- To provide the rotary motion needed by other components such as in rollers and printing press machines.
Shafts are usually made of steel.
Some materials are used in making shafts:
- Cold Rolled Steel: most common due to its low cost
- Hardened Steel: heated rolled steel. Stronger than the cold rolled shaft.
- Stainless steel
Reference: Amatrol Mechanical Drives 1, LAP 3

3. Shaft Design Shafts may be designed with ‘turn downs’
These shafts have smaller diameters at the ends.
When shafts are turned down, a large shaft fillet is used to reduce stresses as possible.
Refer to figures 7-2 and 7-3 in the text (pp )

4. Loads and Stresses on Shafts
Shear Forces
Tensile Forces
Compressive Forces
Bending Moments
Torsions

5. Shaft Fits
Clearance fit: the mating parts have a clearance between them. Also known as slip, slide, or loose fit.
Transition fit: no clearance is present. It is also known as line-to-line fit. In this case pressing is required.
Interference fit: The shaft diameter is larger than the diameter of the hole of the component to be mounted. Some types of it are: press and shrink fits.
An Arbor Press is used to mount the components onto the shafts

6. Shaft Locking Devices Taper-Lock Bushings (see figure7-11 in text)
Quick Detachable (QD) Tapered Bushings
Split-Taper Bushing
Keyless/Compression Bushings
A Quick Detachable (QD) Tapered Bushing

7. Exercise Questions
What is the purpose of the propeller shaft in a car?
Transmitting mechanical power in the form of torque to the rear axle.
Name five types of loading and moments that shafts can be subjected to:
1) Compressive forces
2) Tensile forces
3) Shear forces
4) Bending moments
5) Torsion

8. What three types of shaft fits?
Clearance, line-to-line, and interference fits
Name three types of bushings that can be used to mount components on shafts?
1. Taper-Lock Bushuings
2. Quick Detachable Tapered Bushings
3. Split-Taper Bushings
4. Keyless/Compression Bushings
5. Describe how to mount a component on a shaft with a shrink fit?
The shaft may be freezed in liquid nitrogen to shrink, then the component is mounted on it.
6. What is a disadvantage of shrink fitting?
You are limited by time needed to mount the component on the shaft before the shaft retains its regular dimensions.