Power transmission belt
View Patent ↗A power transmission belt comprising a polyester tensile cord having a heat shrinkage at 100° C. of less than 1% and/or a heat shrinkage at 150° C. of less than about 1.5% and/or a dimensional stability index of less than about 6%. The belt has a heat shrinkage after 24 hours at 100° C. of less than 1%. The polyester may be that sold under the trade name A360 or A363 by Performance Fibers, Inc. or equivalent polyethylene terephthalate. The tensile cord is particularly suited for use in V-belts for variable speed drives.
1. A power transmission belt comprising a tensile cord comprising polyester; the cord characterized by at least one of a heat shrinkage at 100° C. of less than 1%, a heat shrinkage at 150° C. of less than about 1.5%, and a Dimensional Stability Index of less than about 6%; and the belt characterized by a heat shrinkage after 24 hours at 100° C. of less than 1%; with said Index calculated as the sum of percent elongation at 4.5 g/d tensile load and percent heat shrinkage in air at 177° C.
2. The belt of claim 1 wherein the polyester comprises polyethylene terephthalate yarn characterized by a tensile strength of about 7 g/d, a heat shrinkage in air at 177° C. of about 2%, a percent elongation at 4.5 g/d tensile load of about 3%, and a Dimensional Stability Index of less than about 6%.
3. The belt of claim 2 selected from the group consisting of a V-belt, a synchronous belt, and a multi-v-ribbed belt.
4. The belt of claim 3 in the form of a V-belt and adapted for use in a variable-speed belt drive.
5. A variable speed belt drive comprising a sheave and a belt; the belt comprising a tensile cord of polyester; the cord characterized by at least one of a heat shrinkage at 100° C. of less than 1%, a heat shrinkage at 150° C. of less than about 1.5%, and a Dimensional Stability Index of less than about 6%; and the belt characterized by a heat shrinkage after 24 hours at 100° C. of less than 1%; with said Index calculated as the sum of percent elongation at 4.5 g/d tensile load and percent heat shrinkage in air at 177° C.
6. The drive of claim 5 wherein the polyester comprises polyethylene terephthalate yarn characterized by a tensile strength of about 7 g/d, a heat shrinkage in air at 177° C. of about 2%, a percent elongation at 4.5 g/d tensile load of about 3%, and a Dimensional Stability Index of less than about 6%.
7. The drive of claim 6 wherein said belt is a V-belt and said sheave is adjustable.