IP Library Granted Patent US 8,338,999
Granted Patent B2
US 8,338,999 · App. 12/174,165 · Granted Dec 25, 2012

Brushless motor

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Quick Facts
Patent No.
US 8,338,999
App. No.
12/174,165
Granted
Dec 25, 2012
Kind
B2
Abstract

The brushless motor includes a stator having a electromagnetic coil and a position sensor; an axis fixed to the stator; and a rotor having a permanent magnet. The rotor rotates around the axis. The rotor is linked to a driven member that is driven by the brushless motor.

Claims (30)

1. A brushless motor driving a driven member, comprising:

a round-disk shaped stator having a plurality of phase-A coils and a plurality of phase-B coils;

an axis fixed to the stator;

a rotor rotating around the axis and linked to the driven member, the rotor having a first round-disk shaped rotor and a second rotor connected to the first rotor, the first rotor and the second rotor sandwiching the stator therebetween, the first rotor being positioned on one side of the stator and including first magnets, the second rotor being positioned on another side of the stator and including second magnets;

a wiring coupled to the brushless motor, the wiring being provided through an inside of a part of the axis; and

a magnetic yoke made of a ferromagnetic body, the magnetic yoke being disposed on outside faces of the first and second magnets;

wherein the phase-A coils and the phase-B coils are positioned at locations phase-shifted by π/2 from each other;

wherein the phase-A coils and the phase-B coils have no magnetic core;

the number of the first magnets is equal to the number of the phase-A coils;

the number of the second magnets is equal to the number of the phase-B coils;

the first magnets are each positioned at a constant magnetic pole pitch, with adjacent magnets being magnetized in opposite directions;

the second magnets are each positioned at a constant magnetic pole pitch, with adjacent magnets being magnetized in opposite directions;

the first magnets and the second magnets are positioned with their magnetic poles which face towards the stator having mutually different polarity;

the magnetic pole pitch of the first magnets and the second magnets is equal to a coil pitch of the phase-A coils and the phase-B coils;

a magnetic field of the first and second magnets is directed perpendicularly through the stator; and

AC drive signals are delivered to the phase-A coils and the phase-B coils.

2. The brushless motor according to claim 1 , further comprising,

a regenerating circuit that regenerates power from the phase-A coils and the phase-B coils.

3. The brushless motor according to claim 1 , wherein

the phase-A coils and the phase-B coils are coated with resin.

4. A device, comprising:

the brushless motor according to claim 1 ; and

the driven member that is driven by the brushless motor.

5. The device according to claim 4 , wherein

the device is a movable body.

6. The movable body according to claim 5 , wherein

the movable body is a railway vehicle.

7. The brushless motor according to claim 1 , wherein

the rotor enwraps the round-disk shaped stator, and

the first magnets and the second magnets are provided at an inside of the rotor.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 14, 2016
From: SEIKO EPSON CORPORATION
To: GODO KAISHA IP BRIDGE 1
Reel/Frame 040030/0262 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 16, 2008
From: TAKEUCHI, KESATOSHI; NAKAMURA, KAZUYOSHI; SUGIMOTO, MAMORU
To: C/O SEIKO EPSON CORPORATION
Reel/Frame 021245/0819 →