Kx is the frictional resistance of the idler rolls to rotation and the sliding resistance of the belt over the rolls.

Ky The rubber/idler imprint friction, the rolling resistance of the belt flexure as it moves over the idlers and the resistance of the load as it rides over the idlers. In other words how much the belt deflects into the rolls (rubber indentation). There is no equivalent in DIN 22101 for this.

The DIN equivalent of Kx is f which is a global friction factor of 0.01 to 0.04. ■

Yes. You can design according to both methods and compare their results. Too easy?

DIN is a national standard.

CEMA is an industry guide which also knows what it is doing although it is not a legally enforcible standard.

There is plenty of reading material on the subject and less indentation implies a trade off between lower power consumption and idler life, which latter the belt suppliers rarely emphasise. Indentation can vary with time etc. Idler replacement is a straight OPEX - CAPEX fight.

Idler pitch suitability is more important and so DIN would seem more accommodating until the sheer breadth, 0.01 - 0.04, of factor choice can leave design reviewers gasping. I suggest applying CEMA, accept the results and then use those results in a DIN design. Once a any factor is chosen an element of risk is accepted. That's a factor of designer life. ■

In addition to the information already provided by others, the following may be of interest:

http://static.wpe.au.syrahost.com/va...d.pdf?download

Regards,

Lyle ■