Belts 1 Flashcards
Main advantage of belt drives?
Belt will act as a clutch and slip or fail before the equipment does.
Also cost less than chain drives
What are the three main types of belts?
V or wedge belt
Flat belt
Toothed / synchronous / timing
What is the component being turned by the belt refers to as?
Pulley
The v style belt uses what type of pulley?
Sheave
The toothed style belt uses what type of pulley?
Sprocket
The flat style belt uses what style pulley?
Drum style pulley.
Advantages of belt drives over close coupled, roller chain, and gear drives?
They are relatively economical to install and maintain
They are simple to design
They are easy to install
No lubrication is required
Wide variety of applications
Can adjust for any speed requirements
V belt drives are quiet and operate smoothly
Pulleys are less expensive then comparable chain sprockets
Long sheave / pull life
Belts act as a clutch to prevent machine failure
Advantage of flat belts?
They have flexibility and can go around corners
Disadvantage of flat belts?
Relies on high tension to keep belt in contact with pulley and high friction to keep it from slipping
Why must pulleys be crowned and often have flanges?
To keep belt centered and keep it from walking off.
Will smaller or larger sheave wear out faster?
Smaller
Is the slack side or tight side opposite of rotation?
Slack side
What are the two construction categories of v belts?
Envelope and raw edge
How do you know it’s envelope style v belt?
Tensile cord is not showing. And is protected from from elements. (Used outside)
How to you know it’s raw edge style v belt?
Tensile cord is showing. Not protected
How do you know if a belt is sitting right in sheave.
Belt sits just above flush
What are the parts of the v belt (bottom to top)
1) cushion rubber (bottom)
2) tensile cord ( adds strength )
3) insulation rubber (protects cord)
4) backing fabric (top)
What do cogs on a v belt do for us?
Impart more flexibility when used with small diameter pulleys.
Load range of classic v belts?
Less than 1 to 500 HP
Classic v belts contribute to what?
Higher overhung bearing loads and are less efficient to narrow v belt systems
T of F v belts have a high tolerance for poor operating conditions and unusual drive conditions l.
True
Advantage of narrow v belts over classic v belts?
More support, transmits more power, slips less, more support to the center of the belt, greater contact surface with sheave
What is a Fractional horsepower v belt designed for?
Operate drives of less than 1 horsepower
The L in belt identification stands for what?
Fractional horsepower v belt
Are fractional horsepower belts and classic v belts interchangeable?
Yes but not recommended
Advantage of banded belts?
Has backing material across several single belts used to protect belts from whipping or turning over in the sheave. Roll over tendency is vertically eliminated
V ribbed belts are what?
A flat belt with corrugated ridges running longitudinally around the inside surface of the belt.
This makes it easier to keep on pully or easier to steer
Timing belts or synchronous belts are what?
Belts that resemble flat belts with evenly spaced raised teeth that are perpendicular to the long axis of the belt.
Timing belts rely on what to transmit torque?
Positive engagement of belt teeth with complimentary teeth of sprocket
B90
5/8 “ top width
Classic v belt
90 “ inside length
5v500
5= 5/8” top width
V= wedge or narrow v belt
50=50”
0= outside length
6vx350
3/4” top width
Wedge or narrow v belt
X = cogged
35” outside length
2LX500
1/4” top width
L= fractional horse power
Cogged
50” outside length
4/5VX500
4 bands
5/8”
Wedge or narrow
50 outside length
X in belt identification stands for
Belt is Cogged
V in belt identification stands for?
Wedge v belt
If letter is before number in belt identification it means what?
Classic v belt and inside length
A = 1/2”
B= 5/8”
C= 7/8”
D= 1 1/4”
