Pitch Diameter for V-Belt Pulleys

http://www.google.co.uk/search?sourceid=navclient-menuext&ie=UTF-8&q=Pitch+Diameter

http://motion-controls.globalspec.com/Specifications/Motion_Controls/Power_Transmission_Mechanical/Round_Belt_Pulleys

The OD is the physical size of the pulley.

The Pitch diameter is the diameter where the side of the V belt will effectively grip. and it is used to calculate the speed ratio of the drive. The belt actually don't run on the thin side of the belt.

Yes it depends on the size. The pulley is made for a specific belt. If the belt is too small the belt will most probably run on the thin side, If too big it may not fit or will be sticking out on top.

I cannot remember the detail but you could google the manufacturer as indicated on the belt or pulley

Same in theory as for thread. It is as Hendrik described. The diameter at which engagement occurs.

cr3

PITCH DIAMETER

On a straight thread, the pitch diameter is the diameter of the imaginary co-axial cylinder...the surface of which would pass through the thread profiles at such points as to make the width of the groove equal to one-half of the basic pitch. On a perfect thread this occurs at the point where the widths of the thread and groove are equal. On a taper thread, the pitch diameter at a given position on the thread axis is the diameter of the pitch cone at that position.

dear ladies & gentelmen

i want to now what is pitch diameter in v-belt