Belt Drives Flashcards
What is another name for Belt Drives?
Friction Drives
How do Belt Drives transmit power?
By means of belt pressed tightly onto a pulley.
The amount of power that a belt drive can transmit is directly related to the _________.
The grip of the belt on the pulley.
What does the grip of a belt depend on?
- Area of contact
- Material of the belt and pulley
- Tension in the belt
Are crowned Pulleys convex or concave?
Convex
When a pulley is grooved it is called a _____.
Sheave
What are 4 common belt materials used in the industry?
Cotton
Leather
Rubber
Nylon/ other synthetic materials
What does the material determine about the belts friction?
Determines the coefficient of friction
What is Installed Tension?
Tension of the belt when the drive is not running.
What is Effective Tension?
The tension needed on the belt to transmit power without slipping.
When should you retension a new belt?
12 - 24 hours after running
What is deflection with belts.
The allowable change in belt depth due to pressure applied.
How do you calculate deflection in belts?
Where must this delfection be placed or tested?
- For every inch from the centre of one pulley to the centre of the other pulley 1/64” must be given for deflection.
- Halfway between the two centres of the pulleys
How should pulleys look for efficient operation?
Smooth and Rather dull. Not shinny!
What will slippage do to belts?
Polish them and lose grip.
What is Creep?
When a belt slows down on the unloaded side and speeds up on the tight side. Due to elasticity.
What is another name for a belt that is Open Ended?
Reel Stock
What loads and speeds are Fabric Belts used with?
Moderate
What kind of belting is this?
Compass Belting
Compass belting is a single row of _______.
Cords
Flat cord belts have what covering them?
For what reason?
- Fabric
- To protect against wear
Where are Flat Cord Belts used, relating to loads, speeds and shock applications.
Heavy duty areas for high speed, shock load applications
Which has higher capacity and lower stretch: Steel Cable or Cord Flat Belts?
Steel Cable
What are the three layers of Synthetic Belts?
Top Cover, Drive Member Pulley Side.
What are the three main methods of joining Flat Belts?
Chemical, Vulcanized, Mechanical
What is the strongest method of joining Flat Belt ends?
Vulcanized
Chemical Splices use what ingredient?
Adhesives
Name three types of Mechanical Flat-Belt Fasteners.
Wire Lacing
Steel Hinges
Plate Fasteners
What is Vulcanizing?
When you take sliced belt and heat and pressurize them to bond together.
What is the most common method of driving loads between short range pulleys or sheaves?
V-belts drives
What is the main advantage of v-belts?
The simple wedge action of the belt against both sides of the sheave groove.
What is the power transmission efficiency of v-belts?
As high as 93%
Can v-belts handle handle shock loads?
Yes, they can handle shock loads.
What are these?
Label these.
Common V-Belt constructions
What is this?
Where is it used?
What can you not do with these belts?
- Multi Layer cord construction with two bands.
- Long, heavy duty drives.
- Reverse bend them. They can only bend in one direction.
What is this?
Grommet-style V-Belts
How do Straight and Concave V-Belts grip sheaves?
What is this?
Reel-stock V-Belts
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