MECHANISMS QUESTIONS AND
VERIFIED ANSWERS|100%
CORRECT|GRADE A+
Power transmission
What can change?
What stays constant? - ANSWER Components transfer power in a system.
Can change speed and torque
Energy input = energy output
Equation relating power, torque and angular speed - ANSWER P = tw
Gears allow..... - ANSWER transfer of rotational motion between two shafts
Advantages of using gears - ANSWER - Uniform motion
- High speed
- Precise timing
- High efficiency
- Compact design
3 most common power transmission elements - ANSWER 1. Gears
2. Power screws
3. Flexible drives
Gears have constant _________________________ - ANSWER Angular velocity ratio
Two gears must have the same ________________ and ________________ - ANSWER Tooth size and
tooth shape
, What describes tooth size - ANSWER Module or diameter pitch
What describes tooth shape - ANSWER Pressure angle
Equations describing gear ratio "e" - ANSWER Ratio of input to output...
# teeth
gear diameter
torque
and angular speed
When there's more that 2 gears, gear ratio is called _______________ __________ - ANSWER Train
value
Spur gears - ANSWER Most common and easy to manufacture, often inexpensive
Helical gears - ANSWER like spur gears but with angled teeth, more expensive
Provide smoother, quieter operation
Angled teeth result in torque creating an axial force
Rack and pinion - ANSWER A rotating gear that meshes with a bar that has gear teeth along its length.
Changes rotating motion into linear motion.
Bevel gears are a _______ shape and.... - ANSWER Helical gear
2 gears are perpendicular to each other
aka miter gears
Worm gears - ANSWER Non-intersecting perpendicular axes
Often ineffective due to slippage