Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C21/00—Combinations of sliding-contact bearings with ball or roller bearings, for exclusively rotary movement
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2360/00—Engines or pumps
  • F16C2360/23—Gas turbine engines
  • F16C2360/24—Turbochargers

Definitions

• This invention relates to bearing systems for shafts that rotate at high speeds, and more particularly to bearing systems applicable to machines with shafts that rotate at high speed and are exposed at one end to high temperatures, such as turbochargers for internal combustion engines.
• bearing systems must have a long life and must not be subject to breakdown at relatively short intervals such as 500 hours. Since anti-friction bearings such as roller bearings and ball bearings are expensive and have too short an operating life for commercial use in automotive turbochargers, it has been conventional practice to provide sleeve bear ⁇ ings in such applications.
• the bearings of these patents also provided thrust-bearing surfaces as, for example, in U.S. Patent No. 3,390,926 and employed the increased frictional drag at the outer bushing surface to reduce the rota- tional speed of the bushing to a fraction of the rotat ⁇ ing shaft speed and passageways in the bearings them ⁇ selves to direct oil from the outer surface to the inner surfaces and thrust-bearing surfaces.
• U.S. Patent No. 4,370,106 suggests a bearing system for a turbocharger rotor, including an anti-fric ⁇ tion ball bearing at its compressor end and a sleeve bearing at its turbine end.
• This bearing system how ⁇ ever, includes a non-rotating sleeve that forms a non- rotating sleeve bearing at the turbine end of the rotor and an integral non-rotating, support for the outer race of the anti-friction ball bearing at the compressor end of the rotor.
• the sleeve and bearing system is pre ⁇ vented from rotating by a square or out-of-round portion at the compressor end that is mechanically engaged with the turbocharger housing.
• Lubricant is provided between the stationary sleeve and the supporting housing to provide resilience and damping for eccentric motion of the rotor due to its imbalance.
• the differential speed between the sleeve bearing and rotor is the full rotative speed of the rotor. Since the bearing losses are proportional to the square of the rotative speed, this system was a
• the bearing system of this invention provides a reliable, stable, shock- and vibration-resistant, highly efficient, simple, and economical bearing system that is insertable and, thus, permits inexpensive manufacture, maintenance, and repair of the machines in which it is used.
• This system introduces reliable, anti-friction rolling bearings into such applications and comprises basically an elongated outer race adapted to be rotat ⁇ able in its support and to provide an anti-friction rolling bearing and cooperate with a full-floating sleeve to carry the rotating shaft.
• the sleeve bearing may be located by the bearing system within machines such as turbochargers at the end of the machine exposed to high temperature, such as that of a gas passing through a turbine; and the rolling bearing may be located by the system at the cooler end of the machine, for example, adjacent a turbocharger compressor.
• the system may be adapted to be insertable into a stationary machine element and to support the shaft rotatably at two-spaced locations.
• the outer race of the system has preferably an elongated, cylindrical, outer bearing surface adapted to be carried rotatably on a film of lubricant at its interface with the stationary machine element.
• Such a preferable outer race and the full- floating sleeve bearing can include passageways to pro ⁇ vide a flow of lubrication to the interface between the sleeve bearing and the rotating shaft.
• the inner sur- face of the outer race can have an expanding diameter to provide a flow of lubricant from the sleeve bearing to the elements of the rolling bearing.
• the end of the system adjacent the rolling bearing may be provided with outwardly projecting sur- faces, generally transverse to the axis of rotation, to form thrust bearings that may thus be located adjacent the cooler end of a machine.
• lubricating fluid provided to the outer bearing surface of the outer race also lubri- cates one of the outwardly and traversely projecting thrust-bearing surfaces; and lubricating fluid provided to the inner surface of the sleeve bearing also lubri ⁇ cates the rolling elements of the anti-friction bearing and, upon leaving the anti-friction bearing, can lubri- cate the- other outwardly and- traversely projecting thrust-bearing surface.
• the bearing system is sized with regard to the stationary machine element into which it fits so that it may be easily inserted within the stationary machine element and over the rotating shaft and be free to move radially on films of lubrication in response to imbalance of the mass carried by the rotating shaft.
• Fig. 1 is a cross-sectional view taken along a plane through the axis of rotation of a bearing system of this invention
• OMPI Fig. 2 is a cross-sectional view taken along the plane through the axis of rotation of another em ⁇ bodiment of the bearing system of this invention.
• Fig. 3 is a partial cross-sectional view of a bearing system of this invention adapted to use conven ⁇ tional rolling bearings.
• the bearing system of this invention 10 is adapted to support a high-speed, rotating shaft 20 within the stationary elements of a machine 30.
• the new bearing system comprises an outer race 12 adapted to be rotatable in its supporting sta ⁇ tionary machine element 32 and to cooperate with a full- floating sleeve bearing 14 at one end and a rolling bearing 16 at the other end.
• the machine 30, as shown in Fig. 1, may be, for example, a turbocharger for an internal combustion engine, including a turbine 34 at one end and a compressor 36 at the other end.
• the bearing system locates the sleeve bearing 14 adjacent the hot end of the machine, that is, adjacent the tur ⁇ bine 34, and locates the rolling bearing 16 adjacent the cooler end of the machine, that is, adjacent the compressor 36.
• the full-floating sleeve bearing 14 may be of a conventional type, commonly used in turbochargers.
• the roller bearing 16 comprises an inner race 16a and a plurality of rolling elements 16b interposed between shaft 20 and outer race 12.
• the outer race 12 can be machined on its interior surface to cooperate with the inner race 16a and a plurality of rolling elements 16b to provide an anti-friction bearing at the end opposite the sleeve bearing 14.
• the outer race 12 can carry a conventional rolling bearing as shown, for example, in Fig. 3.
• the outer race 12 includes an outer bearing surface 12a adapted to be rotatably carried within the inner bearing
• the outer surface of the outer race may also provide a thrust bearing.
• a thrust bearing may be provided by a pair of outwardly projecting surfaces 12c and 12d projecting transversely of the axis of rotation from the outer surface of the outer race 12.
• surfaces 12c and 12d are a pair of spaced and parallel surfaces that lie normal to the axis of rotation of the rotating system, but it is not necessary that the thrust- bearing surfaces lie normal to the axis of rotation or be parallel.
• the surface 12d may be formed by only that portion of the outer race lying next adja ⁇ cent the rolling elements 16b.
• the entire bearing system 10 is free to rotate in the stationary machine element 32.
• lubricating fluid such as oil
• Such lubricating fluid flows through the passageways 38 and 40 to the interface between the stationary machine element 32 and the outer race 12 of the bearing system.
• the lubricating film clearance between the outer race 12 and the stationary machine element 32 is on the order of about 0.0051 cm. to about .0102 cm.
• the sleeve bearing 14a includes a passageway 14b communicating with passageway 38 to provide a flow of lubrication to the inner bearing surface of the sleeve bearing 14.
• bearing system 10 may be inserted into the machine 30 with the compressor 36 removed, that is, with the end housing 42 and compressor
• the rotating shaft 20 is heated and, thus, must expand axially in response to thermal expan ⁇ sion of the material from which it is made.
• thrust-bearing sur ⁇ faces are provided adjacent the rolling bearing at the cooler end of the machine; the sleeve bearing 14 is located at the hotter end of the machine; and the shaft 20 is free to expand through the sleeve bearing in response to the heat to which it is exposed.
• the bearing system is also provided with thrust-bearings by surfaces 12c and 12d.
• the stationary machine element 32 may be provided with a end surface 32c mating the outwardly projecting bearing surface 12c at the outer surface of the outer race 12 of the bearing system.
• the machine end housing 42 may be provided with a bear- ing surface 42d mating the outwardly projecting, thrust- bearing surface 12d of the outer race 12 of the bearing system.
• lubricating fluid which is provided to the interface between the outer bearing surface 12a of the outer race and the inner bearing surface 32a of the stationary machine element through passageways 38 and 40, will flow between the thrust-bearing surface 12c and the corresponding surface of the stationary machine 32c to lubricate this thrust bearing.
• the bearing system of the invention also per ⁇ mits lubricating fluid to lubricate the sleeve bearing, the rolling bearing, and the other thrust-bearing surface.
• Lubricating fluid through passageway 38 in addition to lubricating the interface between the outer surface 12a of outer race and the inner bearing surface 32a of the stationary element, will flow to passage 14b of the sleeve bearing 14.
• the lubricating fluid will thus form a film of lubrication between the rotating shaft 20 and the sleeve 12a.
• a portion of the lubrica ⁇ tion for the sleeve bearing 12 will flow from the sleeve bearing in the direction of the rolling bearing 16.
• the lubricating fluid will be flung to and will flow over the inner surface 12b of the outer race 12 and provide a flow of lubrication to the rolling elements 16b of rolling bearing 16.
• the lubrication Upon escape from the rolling bearing 16, the lubrication will flow into the interface between thrust-bearing surface 12d and the corresponding bearing face 42d of machine element 42 and thereby lubricate the other thrust bearing.
• an axial passageway may be formed from passageway 40 of the stationary element to and through that portion of the outer race 12 lying between surfaces 12c and 12d. After the oil has left the bearing system, it will flow outwardly of the machine; for example, through the oil drain openings in the machine in a manner known.
• the bearing system of this invention may be used in machines in which the rotating shaft does not experience substantial thermal expansion and may provide anti-friction bearings at each end of the bearing system, as shown in Fig. 2.
• the bearing system 100 is provided with anti- friction bearings 110 and 120 at each end.
• Differences between the bearing systems of Fig. 1 and Fig. 2 include: (a) the substitution of rolling bearing 110, its inner race 112 and spacer 114 for sleeve bearing 14, (b) the lubricating passageway 132 formed in stationary machine element 130, and (c) " the position of the passageway for lubrication 116 formed in the outer race 118.
• the bearing system of the invention is free to move radially in response to unbalanced conditions of the mass carried by the rotat ⁇ ing shaft. Satisfactory stability is obtained if the outer race of the bearing system is allowed to rotate at about one-half the speed of the shaft, but it is preferable that the outer race rotate more slowly as the stability is enhanced at lesser fractions of the speed of the rotating shaft.
• the rotational speed of the outer race 12 is possible to limit the rotational speed of the outer race 12 to a range of from about one-third to about one-tenth of the rotating shaft's speed due to the fric- tional drag imposed by the elongated cylindrical bearing surfaces such as 12a and the thrust-bearing surfaces 12c and 12d of the preferred bearing system.
• Such rota ⁇ tion of the outer race lowers the relative speed between the rolling elements of the rolling bearing and the outer race, substantially enhancing the bearing life of the rolling bearing and substantially reducing the fric- tional losses associated with both the rolling bearing. It is believed the optimum ratio between the speed of the outer race and the speed of the rotational shaft is somewhat less than 0.1.
• sleeve bearing 14 will rotate at speeds in the range of 0.4 to 0.5 times the speed of rotating shaft 20, thus substantially reducing the bearing losses and improving the life of the bearing system.
• the outer surface 12a of the outer race 12 is preferably an elongated cylindrical bearing surface.
• Such a surface provides substantial frictional drag with respect to stationary machine element 32 and thus substantially reduces the relative speeds of rotation between the outer race 12 and the rolling elements 16b and between the rolling elements 16b and their inner race 16a.
• such a preferred embodiment provides substantial spac ⁇ ing between the sleeve bearing 14 and the rolling bear ⁇ ings 16 and permits a simple, insertable bearing system for the shaft 20.
• a bearing system of this invention pro ⁇ vides a stable bearing system. The bearing system is free to move radially in response to imbalance in the rotating mass.
• the bearing system reduces the relative speeds of rotation between the shaft and the bearing system and between the bearing system and the stationary machine element, thereby eliminating the problems of oil whirl and improving the running life of the bearing system.
• Thrust loads may be taken at the cooler end of the machine while the shaft is free to expand in response to its exposure to heat through the sleeve bearing at the hot end of the machine.
• the oil films cushion the rotating shaft against shock and vibration, provide adequate lubrica ⁇ tion, carry away friction-generated heat from the bear ⁇ ing surfaces, and also tend to carry away heat carried down the shaft from the hot end of the machine.
• the bearing system may be easily manufactured at low cost and provide a total bearing system that may be inserted easily into a machine, thus providing inexpensive manu ⁇ facture, repair, and maintenance of the machine.
• the outer race of the bearing system may be manufactured from steel and adapted to rotate within stationary machine elements of either cast aluminum or cast iron. While I have shown and described a preferred embodiment of the invention, other embodiments may be devised without departing from the spirit and scope of the following claims.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Support Of The Bearing (AREA)
• Rolling Contact Bearings (AREA)
• Supercharger (AREA)
• Sliding-Contact Bearings (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=23920727

Family Applications (1)

Country Status (7)

Families Citing this family (4)

Citations (3)

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• 1984
  • 1984-04-05 EP EP19840901651 patent/EP0138984A4/de not_active Withdrawn
  • 1984-04-05 WO PCT/US1984/000439 patent/WO1984004141A1/en not_active Application Discontinuation
  • 1984-04-05 GB GB08427974A patent/GB2148412B/en not_active Expired
  • 1984-04-05 BR BR8406592A patent/BR8406592A/pt unknown
  • 1984-04-05 DE DE19843490178 patent/DE3490178T1/de not_active Withdrawn
  • 1984-04-05 JP JP50163384A patent/JPS60501019A/ja active Pending
  • 1984-12-10 SE SE8406270A patent/SE8406270D0/xx unknown

Patent Citations (3)

Non-Patent Citations (1)

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