Method and system to reduce to wear on a bearing

• US 10,428,826 B2
• Filed: 11/29/2012
• Issued: 10/01/2019
• Est. Priority Date: 12/01/2011
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Stein, Matthias, Steidten, Thomas
• Primary Examiner(s): Lettman, Bryan M
• Assistant Examiner(s): Solak, Timothy P
• Application Number:
  US13/688,343
• Publication Number:
  US 20130142671A1
• Time in Patent Office: 2,497 Days
• Field of Search: 417278, 417293, 417409, 417368, 417411, 41742312, 384100
• CPC Class Codes: F01D 25/16 Arrangement of bearings; Supporting or mounting bearings in casings bearings per se F16C
• CPC Class Codes: F01D 25/22 using working-fluid or other gaseous fluid as lubricant
• CPC Class Codes: F02C 6/12 Turbochargers, i.e. plants for augmenting mechanical power output of internal-combustion piston engines by increase of charge pressure
• CPC Class Codes: F04D 13/12 Combinations of two or more pumps combinations with priming pumps or booster pumps to counteract vapour-lock F04D9/04
• CPC Class Codes: F04D 25/062 Details of the bearings
• CPC Class Codes: F04D 25/16 Combinations of two or more pumps ; Producing two or more separate gas flows
• CPC Class Codes: F04D 29/0413 hydrostatic; hydrodynamic thrust bearings
• CPC Class Codes: F04D 29/043 Shafts
• CPC Class Codes: F04D 29/047 hydrostatic; hydrodynamic
• CPC Class Codes: F04D 29/0513 hydrostatic; hydrodynamic thrust bearings
• CPC Class Codes: F04D 29/056 Bearings
• CPC Class Codes: F04D 29/057 hydrostatic; hydrodynamic

Abstract

A motor vehicle system device having a drive assembly, to which a charging device is assigned, has a compressor having at least one compressor runner supported using at least one bearing, the bearing having a stationary first bearing part and a second bearing part that is operatively connected to the compressor runner. An overpressure source is connected to the bearing, using which an overpressure is able to be produced in a bearing gap that is present between the first bearing part and the second bearing part. The overpressure source is the compressor and/or a part of a tandem pump, which besides the overpressure also makes available low air pressure for a user of the motor vehicle system device. The invention also relates to a method for operating a motor vehicle system device.

Claims

1. A motor vehicle system device, comprising:

a drive assembly for a charging device;

a compressor having at least one compressor runner supported using at least two bearings, each of the bearings having a stationary first bearing part situated in a stationary manner and a second bearing part operatively connected to the compressor runner in a torsionally rigid manner; and

a tandem pump including a low air pressure source and an overpressure source;

wherein an overpressure is produced by the overpressure source and provided to the at least two bearings via a bearing gap between the first bearing part and the second bearing part of each of the bearings, wherein the compressor having an outlet in communication with the bearing gap,

wherein the charging device includes an exhaust gas turbocharger device having the compressor and a turbine, wherein exhaust gas of the drive assembly is suppliable to the turbine via a turbine inlet, wherein the exhaust gas flows out of the turbine from a turbine outlet of the drive assembly, wherein there is an operative connection between the compressor and the turbine via a shaft so that the compressor is drive-able using the turbine, wherein the shaft is situated in a rump housing, wherein the rump housing is situated between the compressor and the turbine, so that heating up of fluid supplied to the compressor by heat of the exhaust gas supplied to the turbine is at least reduced, wherein the rump housing accommodates an electrical drive device that is operatively connected or operatively connectable to the shaft, so that the drive of the compressor is not exclusively provided via the turbine,

wherein the at least two bearings includes an axial bearing and a radial bearing,

wherein the axial bearing and the radial bearing are situated in the rump housing, which is used to support the shaft, the radial bearing being configured to take up forces only in a radial direction, and the axial bearing is configured to prevent the shaft from shifting in an axial direction,

wherein the overpressure in the bearing gaps is such that there is only fluid friction between the bearing parts,

wherein the bearings are fluid-dynamic bearings, so that overpressure takes place automatically upon achieving or exceeding a minimum rotational speed by a rotational speed of the shaft, and wherein the second bearing part is a fluid-dynamic bearing and the first bearing part is a fluid-static bearing,

wherein if the rotational speed of the shaft is less than the minimum rotational speed, the overpressure is provided by the overpressure source,

wherein a cross sectional reducing device or a cross sectional adjustment device is provided between the overpressure source for providing the overpressure and the axial bearing and the radial bearing for setting the overpressure produced in the bearing gap of each of the axial bearing and the radial bearing, and

wherein the second bearing part of the axial bearing is a radial projection extending outwardly from the shaft in the radial direction, and which cooperates with the first bearing part of the axial bearing for providing axial fixing of the shaft.

2. The motor vehicle system device according to claim 1, wherein the drive assembly is a fuel cell assembly having at least one fuel cell and at least one electric machine fed with electric power by the fuel cell.

3. The motor vehicle system device according to claim 1, wherein the tandem pump is driven electrically.

4. The motor vehicle system device according to claim 1, wherein at least one of the axial bearing and the radial bearing is configured as an aerodynamic or aerostatic sliding bearing.

5. The motor vehicle system device according to claim 1, wherein the low air pressure source provides low air pressure to a brake booster.

6. The motor vehicle system device of claim 1, wherein the overpressure is produced by the overpressure source and the compressor.

7. The motor vehicle system device of claim 1, wherein the source for providing the overpressure is the tandem pump.

8. The motor vehicle system device of claim 1, wherein the source for providing the overpressure is the compressor.

9. A method for reducing wear of at least two bearings of a motor vehicle device having a drive assembly for a charging device, the method comprising:

producing an overpressure using at least part of a tandem pump, the tandem pump including a low air pressure source and an overpressure source;

wherein the overpressure is provided in a bearing gap between a stationary first bearing part situated in a stationary manner and a second bearing part of each of the at least two bearings, the at least two bearings being operatively connected, in a torsionally rigid manner, to a compressor runner of a compressor via the second bearing part and supporting the compressor runner, wherein the compressor having an outlet in communication with the bearing gap,

wherein the charging device includes an exhaust gas turbocharger device having the compressor and a turbine, wherein exhaust gas of the drive assembly is suppliable to the turbine via a turbine inlet, wherein the exhaust gas flows out of the turbine from a turbine outlet of the drive assembly, wherein there is an operative connection between the compressor and the turbine via a shaft so that the compressor is drive-able using the turbine, wherein the shaft is situated in a rump housing, wherein the rump housing is situated between the compressor and the turbine, so that heating up of fluid supplied to the compressor by heat of the exhaust gas supplied to the turbine is at least reduced, wherein the rump housing accommodates an electrical drive device that is operatively connected or operatively connectable to the shaft, so that the drive of the compressor is not exclusively provided via the turbine,

wherein the at least two bearings includes an axial bearing and a radial bearing,

wherein the axial bearing and the radial bearing are situated in a rump housing, which is used to support the shaft, the radial bearing being configured to take up forces only in a radial direction, and the axial bearing is configured to prevent the shaft from shifting in an axial direction,

wherein the overpressure in the bearing gaps is such that there is only fluid friction between the bearing parts,

wherein the bearings are fluid-dynamic bearings, so that overpressure takes place automatically upon achieving or exceeding a minimum rotational speed by a rotational speed of the shaft, and wherein the second bearing part is a fluid-dynamic bearing and the first bearing part is a fluid-static bearing,

wherein a cross sectional reducing device or a cross sectional adjustment device is provided between the overpressure source for providing the overpressure and the axial bearing and the radial bearing for setting the overpressure produced in the bearing gap of each of the axial bearing and the radial bearing, and

wherein the second bearing part of the axial bearing is a radial projection extending outwardly from the shaft in the radial direction, and which cooperates with the first bearing part of the axial bearing for providing axial fixing of the shaft.

10. The method according to claim 9, further comprising:

prior to producing the overpressure, determining that a rotational speed of the compressor runner is less than a threshold minimum rotational speed;

wherein the overpressure between the bearing parts of each of the axial bearing and the radial bearing is produced responsive to the determination.

11. The method of claim 9, further comprising:

making available low air pressure via the low air pressure source of the tandem pump.