# US 8,569,918 B2 · Bearing assembly

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- Number: US 8,569,918 B2
- Document ID: US8569918B2
- Status: Granted
- Kind: B2
- Application number: 13/245,359
- Filed: 2011-09-26
- Published: 2012-01-19
- Granted: 2013-10-29
- Earliest claimed: 2009-03-26
- Assignees: ABB AB
- Applicants: Peter Isberg; Per-Olof Lindberg
- Inventors: Peter Isberg; Per-Olof Lindberg
- Web page: https://patentgrep.com/patent/US8569918B2

## CPC

- H02K 5/1672: {radially supporting the rotary shaft at both ends of the rotor (H02K5/1677 takes precedence)}
- F16C 19/522: {related to load on the bearing, e.g. bearings with load sensors or means to protect the bearing against overload}
- F16C 21/00: Combinations of sliding-contact bearings with ball or roller bearings, for exclusively rotary movement (F16C17/24, F16C19/52 take precedence)
- F16C 33/80: Labyrinth sealings {(F16C33/761 takes precedence)}
- F16C 39/02: using mechanical means
- F16J 15/164: {the sealing action depending on movements; pressure difference, temperature or presence of leaking fluid}
- H02K 5/124: Sealing of shafts
- H02K 5/1732: {radially supporting the rotary shaft at both ends of the rotor (H02K5/1737 takes precedence)}
- F16C 2326/10: Railway vehicles
- F16C 2380/26: Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators
- H02K 7/083: {radially supporting the rotary shaft at both ends of the rotor (H02K7/086, H02K7/09 take precedence)}
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS

## Abstract

A bearing assembly for an electrical motor, including a shaft, a housing, and a main bearing between the shaft and the housing, the shaft being surrounded by a rigid sleeve for functioning as an auxiliary bearing in case of a breakdown of the main bearing and as a grease sealing under normal operation.

## Claims

### Claim 1

A bearing assembly for an electrical motor, the bearing assembly comprising:
a shaft, a housing, and a main bearing between the shaft and the housing,
a rigid sleeve surrounding the shaft and being configured to function as an auxiliary bearing in case of a breakdown of the main bearing, and
a clearance between the sleeve and the shaft, the clearance being smaller than an air-gap between a stator and a rotor of the motor,
wherein the sleeve has a portion of a conical inner surface facing the shaft and having an increasing diameter towards the main bearing, the sleeve together with a centrifugal effect of the rotating shaft providing a pumping action that directs grease from a region of the conical inner surface towards the main bearing.

### Claim 2 (depends on 1)

The bearing assembly of claim 1, wherein the clearance between the sleeve and the shaft is at most 0.6 mm.

### Claim 3 (depends on 1)

The bearing assembly of claim 1, wherein the width of the sleeve portion functioning as the auxiliary bearing is at least 10 mm.

### Claim 4 (depends on 1)

The bearing assembly of claim 1, wherein the clearance between the sleeve and the shaft functions as a grease sealing under normal operation conditions.

### Claim 5 (depends on 1)

The bearing assembly of claim 1, wherein the sleeve is an integral part of the housing.

### Claim 6 (depends on 1)

The bearing assembly of claim 1, wherein the housing includes a motor end shield and wherein the sleeve is a part of the motor end shield.

### Claim 7 (depends on 1)

The bearing assembly of claim 1, wherein the sleeve is positioned between the main bearing and the interior of the housing.

### Claim 8 (depends on 1)

The bearing assembly of claim 1, wherein the material of the sleeve contains a lubricating agent.

### Claim 9 (depends on 8)

The bearing assembly of claim 8, wherein the lubricating agent is graphite.

### Claim 10

An electrical motor comprising a bearing assembly comprising:
a shaft, a housing, and a main bearing between the shaft and the housing,
a rigid sleeve surrounding the shaft and being configured to function as an auxiliary bearing in case of a breakdown of the main bearing, and
a clearance between the sleeve and the shaft, the clearance being smaller than an air-gap between a stator and a rotor of the motor,
wherein the sleeve has a portion of a conical inner surface facing the shaft and having an increasing diameter towards the main bearing, the sleeve together with a centrifugal effect of the rotating shaft providing a pumping action that directs grease from a region of the conical inner surface towards the main bearing.

### Claim 11 (depends on 10)

The electrical motor according to claim 10, wherein the electrical motor is a traction motor.