Oil-shear Drive Systems
Hydrodynamic forces in oil-lubricated bearings produce unwanted friction (drag) which causes some loss of efficiency. However, the principle has been put to use in the development of types of mechanical power drive in which torque is transmitted by the shear of an oil film between two surfaces. There are two main types of drive that use oil-shear. (1) Based on shear of an oil film between two flat surfaces (plates or discs); this type can be used for drive engagement/release (ie a clutch), for braking effect, or for a combined clutch/brake system. (2) Continuously variable drives in which an oil film is sheared to provide friction between rolling interfaces (eg rollers between flat or contoured surfaces). These types have been developed in various forms: the general principles and characteristics of each are discussed further in this chapter.
KeywordsOutput Shaft Friction Disc Power Shaft Variable Speed Drive Clutch Disc
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