# US 2013/0278116 A1 · Brushless dc motor

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- Number: US 2013/0278116 A1
- Document ID: US20130278116A1
- Status: Published application
- Kind: A1
- Application number: 13/532,529
- Filed: 2012-06-25
- Published: 2013-10-24
- Earliest claimed: 2012-04-18
- Assignees: Samsung Electro-Mechanics Co., Ltd.
- Inventors: Jin Sun Min; Young Sun Yoo
- Web page: https://patentgrep.com/patent/US20130278116A1

## CPC

- H02K 5/1675: {radially supporting the rotary shaft at only one end of the rotor (H02K5/1677 takes precedence)}
- F16C 17/107: {with at least one surface for radial load and at least one surface for axial load}
- G11B 19/2009: {Turntables, hubs and motors for disk drives; Mounting of motors in the drive (means for clamping of disk to turntable G11B17/022 and subgroups)}
- F16C 2370/12: Hard disk drives or the like
- 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
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

Disclosed herein is a brushless DC motor that ensures stable driving of a shaft that rotates in a hollow of a bearing by using a bearing with a flat bottom surface and a tapered top. A contact height between an inner peripheral surface of the bearing and an outer peripheral surface of the shaft is larger than a contact height between an outer peripheral surface of the bearing and an inner peripheral surface of a bearing holder.

## Claims

### Claim 1

A brushless DC motor, comprising:
a shaft;
a bearing having a hollow cylindrical shape to rotatably support the shaft and including a taper on the top thereof;
a bearing holder having the hollow cylindrical shape to support the bearing;
a base fixing the bearing holder;
a rotor including a hub and a magnet; and
a stator including a core and a plurality of coils wound on the core and fixed to an outer peripheral surface of the bearing holder.

### Claim 2 (depends on 1)

The brushless DC motor as set forth in claim 1, wherein the taper is inclined downwardly outward from the center of the bearing.

### Claim 3 (depends on 1)

The brushless DC motor as set forth in claim 1, wherein the height of an inner peripheral surface of the bearing is larger than that of an outer peripheral surface of the bearing.

### Claim 4 (depends on 1)

The brushless DC motor as set forth in claim 1, wherein the bottom surface of the bearing is flat.

### Claim 5 (depends on 1)

The brushless DC motor as set forth in claim 1, wherein a slope surface is formed on the top of an inner peripheral surface of the bearing holder.

### Claim 6 (depends on 1)

The brushless DC motor as set forth in claim 1, wherein the taper of the bearing is placed below the slope surface of the bearing holder.

### Claim 7 (depends on 1)

The brushless DC motor as set forth in claim 1, wherein the top of the bearing is stepped along an outer surface thereof.

### Claim 8 (depends on 3)

The brushless DC motor as set forth in claim 3, wherein the height of the inner peripheral surface of the bearing is 1.1 times larger than that of the outer peripheral surface of the bearing.

### Claim 9

A brushless DC motor, comprising:
a shaft;
a bearing having a hollow cylindrical shape to rotatably support the shaft and including a taper on the top thereof;
a bearing holder having the hollow cylindrical shape to support the bearing;
a base fixing the bearing holder;
a rotor including a magnet and a hub with a step portion on the bottom surface thereof; and
a stator including a core and a plurality of coils wound on the core and fixed to an outer peripheral surface of the bearing holder.

### Claim 10 (depends on 9)

The brushless DC motor as set forth in claim 9, wherein the step portion is placed opposite to the top of the bearing.

### Claim 11 (depends on 9)

The brushless DC motor as set forth in claim 9, wherein the step portion has a ring shape, which is formed on the bottom surface of the hub.

### Claim 12 (depends on 9)

The brushless DC motor as set forth in claim 9, wherein the taper is inclined downwardly outward from the center of the bearing.

### Claim 13 (depends on 9)

The brushless DC motor as set forth in claim 9, wherein the height of an inner peripheral surface of the bearing is larger than that of an outer peripheral surface of the bearing.

### Claim 14 (depends on 9)

The brushless DC motor as set forth in claim 9, wherein the bottom surface of the bearing is flat.

### Claim 15 (depends on 9)

The brushless DC motor as set forth in claim 9, wherein a slope surface is formed on the top of an inner peripheral surface of the bearing holder.

### Claim 16 (depends on 9)

The brushless DC motor as set forth in claim 9, wherein the top of the bearing is stepped along an outer surface thereof.

### Claim 17 (depends on 13)

The brushless DC motor as set forth in claim 13, wherein the height of the inner peripheral surface of the bearing is 1.1 times larger than that of the outer peripheral surface of the bearing.