Belt Auction

why flat belts are more efficient than V-belts ?

flat belt has an efficiency of about 98% while the efficiency of a V-belt ranges from about 70% to 96%. Why? and i would be grateful if you can give me a link to read or download this article "Efficiency of Synchronous Belts and V-Belts," Proc. Nat. Conf. Power Transmission, vol.5, Illinois Institute of Technology, Chicago, Nov. 7-9, 1978, pp 265-271. and a link to download this paper : T. C. Firbank, Mechanics of the Flat Belt Drive, ASME paper no. 72-PTG-21. thanks in advance.

Public Comments

1. Maybe this is a case of over-think; but simply put, a flat belt has less frictional contact area? Probably way to simplistic for you needs.
2. They are more efficient because they produce less heat. The pulley on a V belt is cut slightly smaller than the V belt itself, so as any point on the V belt enters the pulley and depending on the load, the V is pulled down into the groove in the pulley. This takes a significant amount of energy to wedge that belt down into the pulley. The trade off is the larger the load the more the V belt sinks into the pulley so that it gets a better grip. But the energy it takes to continuously wedge that V into the pulley and then 180 degrees later, to unwedge the pulley, generates quite a bit of heat. Put your hand on a pulley after it has been running for a while and you will feel it is hard enough to burn you (so touch carefully) The flat belts on the other hand only have to lie over the pulleys and don't waste energy being wedged into the metal grooves. The flat belt relies on a belt tensioner to keep a frictional pressure between the pulley and the belt itself.
3. Go through the source link where you can have a ample information.