The friction traction and radial composite stress of each ring of traditional friction roll have a huge difference. In order to solve the problem the paper has a conclusion through mechanical analysis and experimental verification, that the radial integrated stress of each ring is the same when the friction traction is same. Each groove of multi-groove friction roll is designed with different section according to the results of mechanical analysis, and then the different groove has different equivalent friction coefficient. As a friction reel with 2-slot, which equivalent friction coefficient of one groove is 0.6, another one is 0.2. Such 2-slot friction reel can provide the traction force as well as the traditional 4-slot friction do, so that the volume can be reduced by one half. The difference of each groove of 2-slot friction reel is less than 5%, which is less than 1% of the difference of traditional friction reel. So this friction reel with various section grooves is a good way of winch lightweight design for its force balance and light weight.
