WEAR OF COATED AND UNCOATED PRIMARY CLUTCH SHEAVES IN A CVT
In research conducted at Brigham Young University, four coatings were tested for their ability to increase the wear life of primary clutch sheaves made of A390 die-cast aluminum used in continuously variable transmissions (CVT). The coatings tested were: hard chrome, electroless nickel metal, hard coat anodizing and composite ceramic coating. A wear test stand was developed to duplicate wear found on CVTs currently in use. The wear was evaluated using four methods. The test first method characterized the shift delay properties of the worn CVTs while running on the wear test stand. As the CVT was run on the wear test stand a delay in shifting would develop during the unloading cycles. The second method used an ATV and chassis dynamometer to evaluate the change in performance with wear. The third method used a profilometer to evaluate the amount of material lost, through wear.