Belt Length Calculation 1

[ionelz]

Could someone please explain the relation between "Pulley diameter over balls" and Belt ?
How can a calculate the Outside Belt length ?

01. I have a Gate Micro V Belt, belt thickness is aprox 5.15 mm
02. Pulley Groove angle is 37 deg and Ball dia is 2.5
03. DOB is 62

...I know we need another pulley for belt

But, my question is, how to correlate radius of Pulley DOB with Belt

Is the center of Pulley ball coincident with Belt ball ? (2.5 mm ball in belt groove)
What is the relation then to Backside of belt ?

 

[racookpe1978]

DO NOT GUESS! Do NOT "wrap a tape" nor measure the old belt - it has stretched.

See, for example, this calculator from a manufacturer:

http://www.durabelt.com/beltlengthcalculator.php

 

[ionelz]

Could someone answer this ?
What is the relation between Radius of center gauge ball in pulley groove and center of gauge ball in belt groove ? (a section cut thru belt wrapped around pulley)
Are these radius equal ?
The center ball tie together the pulley and belt ?

 

[tbuelna]

Measurement over pins/balls is just a convenient way to check the diameter of the v-groove space of your pulley. The same technique is used to inspect the diameter of external spaces of gear teeth, spline teeth, and screw threads. The pulley groove diameter is defined by the distance over two specific sized gage pins/balls resting against the pulley groove surfaces and diametrically opposed to each other. The angle between the pulley groove surfaces must also be considered with the over pins measurement when establishing the size of the groove. There is an older SAE standard for inch size V-belt and pulley dimensions using gage pins/balls, and it provides a relationship between the pulley and belt diameters. I don't have a copy of the spec, but there is a table in Machinery's Handbook.

 

[ionelz]

ok, than how to calculate belt length ?
how to correlate, how to "jump" from pulley to belt ?
I do not have a section of pulley-belt togheher
a pulley is usually defined by DOB (diameter over ball), ex : DOB=100, ribs angle 37, pitch ribs=3.56
Belt V is : angle 40, pitch=3.56, thick 5 mm

 

[ionelz]

supplier say : belt effective length is ...belt outside length is ....
so I need to correlate effective/outside in belt with pulley
what effective in belt correspond in pulley ?

 

[3DDave]

http://www.gates.com/~/media/Files/.../Manuals/Light Power and Precision Manual.pdf