The present invention relates to superchargers for internal combustion engines and more particularly, to an improved, low cost and compact self-lubricating centrifugal supercharger employing a rotary driven oil slinger that avoids excessive lubrication disposition onto and around the shafts, gears and associated bearings and excessive lubrication build-up on the rapidly rotating gears that cause power losses and an undesirable rise in temperature of the lubrication oil.
The use of oil slingers as an economical means of lubricating intermeshing gears and associated bearings has been well known for many years. See, for example, Gear Handbook, published in 1962 by McGraw-Hill Book Company. A gear or disc is mounted on a rotating shaft, typically a drive shaft, so as to pass a lower portion of the gear or disc through an internal reservoir of lubrication oil. As the rotating gear or disc passes through the reservoir of lubrication oil, it lubricates the intermeshing gears and associated bearing assemblies by slinging a mist of oil from the reservoir onto the gears and bearings. Oil slingers have been used in a variety of high speed applications, including superchargers. See, for example, U.S. Pat. No. 1,974,974 (Puffer), U.S. Pat. No. 3,734,637 (Beck) and U.S. Pat. No. 4,090,588 (Willover). While such internal lubricating systems have several cost advantages over external systems, it has been found that during operation, these rapidly rotating oil slingers tend to throw an excessive volume of lubricating oil onto the gears and bearing assemblies inside the transmission case. Also, the rotating gears will collect lubricating oil on the perimeter of their toothed surfaces creating, in effect, rolling “doughnuts” of lubricant. Oil splashing onto the gears from the reservoir exacerbates the situation. The result of the entrained oil carried by the meshing gears in a supercharger is a significant power loss due to the shearing of the viscous lubricant film and resistance to rotation created by the large volume of lubricating oil engaging the mechanical components. Also, a significant rise in the temperature of the oil within the internal reservoir results which can ultimately lead to product failure. The supercharger of the present invention retains the simplified low cost solution for effecting lubrication of the gears and bearing assemblies provided by a rotating oil slinger, while effectively and efficiently controlling the volume and flow of lubricating oil so as to prevent the above-described power drain and associated temperature rise in the lubricating oil that was heretofore inherent in such lubricating systems.