Chains and Belt Drives

Question 1

Difference between a belt drive and a chain drive

Answer 1

Belt drives are for high speed, low torque applications, while chain drives are for low speed, high torque applications.

Question 2

Purpose of belt and chain drives

Answer 2

Used to transmit power between parallel shafts.

Question 3

Characteristics of Flat Belts

Answer 3

Quieter than VeeBelts, higher efficiency, run in barrel-shaped pulleys to prevent slipping.

Question 4

Two main types of belts

Answer 4

VeeBelts and Flat Belts.

Question 5

Characteristics of VeeBelts

Answer 5

Common type, Vee shape enhances friction with pulley, lower efficiency due to heat generation.

Question 6

Toothed Belt Drives

Answer 6

Engage in pulley grooves to prevent slipping, ensuring constant speed ratios.

Question 7

Key points about Roller Chains

Answer 7

Made of steel, suitable for high torque, and achieve constant speed ratios with no slip.

Question 8

Comparison of Belt and Chain Drive in terms of lubrication

Answer 8

Chain drives need frequent lubrication, while belt drives do not require lubrication.

Question 9

Lifespan comparison between Belt and Chain Drives

Answer 9

Belt drives have a higher life expectancy (~60k mi) compared to chain drives (~30k mi).

Question 10

Power loss in Belt vs Chain Drives

Answer 10

Belt drives have higher power loss (~11%) compared to chain drives (~3%).

Question 11

Belt Geometry analysis - Angle of Contact for Small Pulley

Answer 11

Calculated using the formula involving the radius of pulleys and center distance.

Question 12

Belt Length Calculation

Answer 12

Depends on the diameters of the pulleys and the distance between them.

Question 13

Importance of Friction in Belt Drives

Answer 13

Required to transmit force between belt and pulley; essential to avoid belt slip.

Question 14

Centrifugal Force in Belt Drives

Answer 14

Acts to pull the belt from the pulley, affecting tension and slip.

Question 15

Pre-Tension in Belts

Answer 15

Belts are installed with an initial pre-tension to take out slack and maintain tension balance when rotating.

Question 16

Belt Drive Analysis - Centrifugal Force Effect

Answer 16

Requires compensation in the tension calculation to prevent slip.

Question 17

Additional Friction in Vee Belts

Answer 17

Vee belts provide additional frictional grip along the sides of the pulley.

Question 18

Equation for Belt Pre-Tension

Answer 18

Calculated based on the tensions on the tight and slack sides of the belt.

Question 19

Maximum Power Transmission in Belt Drives

Answer 19

Depends on the strength of the belt and the tension on the tight side.

Question 20

Key Summary Points for Belt and Chain Drives

Answer 20

Belt drives are suitable for high speed/low torque; chain drives for low speed/high torque. Calculations for both are similar.

Question 21

Linked Belts

Answer 21

• Small sections of vee belts joined by pins
• Used where shafts would have to be dismantled to
  fit continuous belt.