Mechanical

Question 1

Reasons to reduce friction

Answer 1

Improve mechanical efficiency

Reduce wear on components

Reduce costs

Question 2

How to reduce friction

Answer 2

Lubricant

Roller bearings

Bush

Thrust bearing - high axial load

Journal - to support axle/shaft

Question 3

Drive Systems

Transmit mechanical power from one place to another

Answer 3

Simple gear - cheap/ lower than etc

Compound gear + less space
- more expensive

Worm + wheel
+ large torque
+ reduces speed
+ accurate

Worm + nut
+ rotational->linear

Rack + pinion
+rotational -> linear
+ accurate

Question 4

Why should we use gear systems?

Answer 4

+ transmit torque

• expensive to manufacturer
• take up space
• mechanical losses

Question 5

Belt/ chain ( simple way to move objects)

Answer 5

Flat
+low costs
+ allows slippage
- lower power transmission

Vee
+ higher power transmission
- more expensive

Question 6

Reason why we use belt/ chain

Answer 6

+ lower cost
+ less space
- less power

Question 7

How to calculate mechanical power

Answer 7

P=f x v
P= 2 pie n T

F - force

V - velocity

Power = 2 pie rotational speed ( sec ) torque

N= rpm divided by 60

Question 8

Couplings ads and dis ads

Answer 8

+ allows shafts to be disengaged during operation
+ can skip preventing damage

• expensive components and require maintenance
• takes up large amount of space