Turbocharger drive and planet bearing therefor

• US 5,567,056 A
• Filed: 09/29/1994
• Issued: 10/22/1996
• Est. Priority Date: 09/29/1994
• Status: Expired due to Term

• Current Assignee: Electro-Motive Diesel Incorporated (Caterpillar Incorporated)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Blase, James L., McCreary, Charles H.
• Primary Examiner(s): Hannon, Thomas R.
• Application Number:
  US08/315,205
• Time in Patent Office: 754 Days
• Field of Search: 384/286, 384/289-291, 384/313, 384/322, 384/372, 384/373, 384/380, 384/114, 384/115, 384/118, 384/120
• US Class Current: 384/286
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02B 39/06 the engine torque being divided by a differential gear for driving a pump and the engine output shaft
• CPC Class Codes: F16C 2360/24 Turbochargers in general F02C6/12
• CPC Class Codes: F16C 2361/61 Toothed gear systems, e.g. support of pinion shafts in general F16H57/02
• CPC Class Codes: F16C 33/1055 from radial inside, e.g. via a passage through the shaft and/or inner sleeve
• CPC Class Codes: F16H 2057/085 Bearings for orbital gears
• CPC Class Codes: F16H 57/0404 Lubricant filters
• CPC Class Codes: F16H 57/0479 Gears or bearings on planet carriers
• CPC Class Codes: F16H 57/0482 Gearings with gears having orbital motion
• CPC Class Codes: F16H 57/082 Planet carriers

Abstract

A planet bearing and gear assembly for the carrier of a speed increasing planetary gear train for driving a diesel engine turbocharger or the like includes an enlarged diameter gear bore and associated bearing outer diameter for lightening the gear and increasing the bearing area to at least 50 percent and preferably more than 65 percent greater than those of the bearing inner wall and the outer diameter of an associated support pin. Self-cleaning of unfiltered dirt particles in the engine lubricating oil is provided by dirt expulsion passages formed by flats at the edges of an oil supply groove in the planet bearing while operation with entrained dirt particles capable of passing through the engine lubricating oil filters is improved by increased oil film thickness resulting from reduced bearing loads due to reduction of mass of the planet gears and increased bearing surface. Circumferential oil grooves in the inner surface help cool the bearing prior to delivery to an oil supply groove which is configured with a flat floor toward one end adjacent oil supply holes and an arcuate floor on the other end to improve manufacturing accuracy and convenience.

Claims

1. A planet bearing for rotatably supporting a planet gear in an engine turbocharger drive, said bearing including an annular ring having an outer bearing surface coaxial with a cylindrical inner wall and opposite first and second ends, an oil supply groove recessed below the bearing surface and bounded axially by shoulders adjacent the ends, oil supply means through the bearing from the inner wall to the supply groove, and the improvement comprising:

passage means in at least one of said shoulders connecting said oil supply groove with an adjacent one of said ends and defining a path for expulsion of dirt-carrying oil from the bearing lubrication oil supply,

wherein said passage means are provided in both of said shoulders, and

wherein said passage means comprise flats formed along otherwise convex peripheries of said shoulders to effectively increase local clearance between the shoulders and an associated planet gear.

2. A bearing as in claim 1 wherein said oil supply means comprise supply holes.

3. A bearing as in claim 2 wherein said oil supply means further comprise annular grooves along the inner wall and communicating with said supply holes.

4. A bearing as in claim 3 wherein there are at least three of said annular grooves spaced axially along the inner wall and communicating with at least three of said supply holes.

5. A planet bearing for rotatably supporting a planet gear in an engine turbocharger drive, said bearing including an annular ring having an outer bearing surface coaxial with a cylindrical inner wall and opposite first and second ends, an oil supply groove recessed below the bearing surface and bounded axially by shoulders adjacent the ends, oil supply means through the bearing from the inner wall to the supply groove, and the improvement comprising:

passage means in at least one of said shoulders connecting said oil supply groove with an adjacent one of said ends and defining a path for expulsion of dirt-carrying oil from the bearing lubrication oil supply, and

wherein said oil supply groove has a floor with a flat portion at one end adjoining an arcuate portion at an opposite end.

6. A bearing as in claim 5 wherein said oil supply means comprise supply holes opening into said supply groove near said one end.

7. A turbocharger planetary drive train having an engine driven planet carrier rotatable at a high speed, a ring gear fixed during a drive mode, a sun gear drivably connected with a turbocharger compressor and a plurality of planet gears rotatably carried by the planet carrier and engaging the sun and ring gears for driving the compressor at an elevated speed greater than that of the planet carrier,

wherein the planet carrier includes axially spaced end walls extending radially outward from a rotational axis of the carrier with means in the walls receiving a plurality of removable pins in angularly spaced locations between said walls, said planet gears being rotatably supported on the pins by bearings that are fixedly mounted on the pins within and engaging internal bores of the planet gears for rotation of the planet gears on the pin carried bearings, and the improvement wherein:

the planet gears are made light by sizing their internal bores at least 50 percent larger in diameter than the diameters of their respective supporting pins,

whereby the specific loading and wear on the planet gear bearings is minimized by the relatively low centrifugal forces of the light planet gears on their bearings and the high load carrying area of the bearings,

wherein each said bearing includes an annular ring of bearing material having a cylindrical outer surface coaxial with a cylindrical inner wall and opposite first and second ends, the outer surface being received within and engaging the internal bore of the associated gear and the inner wall receiving the associated pin to support the bearing and gear on the carrier, an oil supply groove recessed below the outer surface and bounded axially by shoulders adjacent the ends, an oil supply hole through the bearing from the inner wall to the supply groove and passage means in at least one of said shoulders connecting said oil supply groove with an adjacent one of said ends and defining a path for expulsion of dirt-carrying oil from the bearing lubrication oil supply,

wherein said passage means comprise flats formed along otherwise convex peripheries of said shoulders to effectively increase local clearance between the shoulders and an associated planet gear,

wherein said oil supply groove has a floor with a flat portion at one end adjoining an arcuate portion at an opposite end, and

wherein there are at least three of said annular grooves spaced axially along the inner wall and communicating with at least three of said supply holes.