IP Library › Granted Patent US 6,879,068
Granted Patent B2
US 6,879,068 · App. 10/361,164 · Granted Apr 12, 2005

Power generator, timepiece and electronic device having the same, and cogging torque adjustment method for the same

Assignee: Seiko Epson Corporation
View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 6,879,068
App. No.
10/361,164
Granted
Apr 12, 2005
Kind
B2
Abstract

Protrusions ( 260 ) for adjusting the cogging torque of a rotor ( 21 ) are formed on a stator ( 22 ) in a small-size power generator ( 20 ). Since the protrusions ( 260 ) are formed on an inner periphery of a rotor accommodation hole ( 230 ) within an angular range of ±45° around a magnetic flux direction of a first magnetic circuit ( 100 ) having a smaller magnetic reluctance at a rotation center of the rotor ( 21 ), the cogging torque can be effectively reduced. Accordingly, even when the size of components such as an oscillating weight and a power spring is reduced for making a thin timepiece, rotation startability of the rotor can be improved, thus improving power generation efficiency of the small-size power generator.

Claims (46)

1. A power generator comprising:

a rotor having a permanent magnet rotated by a transmitted rotary drive force;

a stator having a rotor accommodation hole, the rotor being disposed in the accommodation hole;

a magnetic core, and a power-generating coil wound around the magnetic core, the magnetic core, atator and rotor constituting a first magnetic circuit, and a part of the stator around and adjacent to the rotor constituting a second magnetic circuit; and

further comprising a protrusion projecting toward the rotor formed on the inner periphery of the rotor accommodation hole of the stator within an angular range of ±45° around a magnetic flux direction of the first magnetic circuit at a rotation center of the rotor.

2. The power generator according to claim 1 , wherein the protrusion is formed within an angular range of ±10° around the magnetic flux direction of the first magnetic circuit at the rotation center of the rotor.

3. The power generator according to claim 2 , wherein the protrusion is formed in the magnetic flux direction of the first magnetic circuit at the rotation center of the rotor.

4. The power generator according to claim 1 , further comprising an oscillating weight, and a power-generating gear train that provides said transmitted rotary drive force to the rotor by transmitting a rotation of the oscillating weight.

5. A timepiece comprising:

a power generator comprising:

a rotor having a permanent magnet rotated by a transmitted rotary drive force;

a stator having a rotor accommodation hole, the rotor being disposed in the accommodation hole;

a magnetic core, and a power-generating coil wound around the magnetic core, the magnetic core, stator and rotor constituting a first magnetic circuit, and a part of the stator around and adjacent to the rotor constituting a second magnetic circuit; and

further comprising a protrusion projecting toward the rotor formed on the inner periphery of the rotor accommodation hole of the stator within an angular range of ±45° around a magnetic flux direction of the first magnetic circuit at a rotation center of the rotor;

a time display; and

a processor for actuating said time display by an electric energy generated by the power generator.

6. An electronic device comprising:

a power generator comprising:

a rotor having a permanent magnet rotated by a transmitted rotary drive force;

a stator having a rotor accommodation hole, the rotor being disposed in the accommodation hole;

a magnetic core, and a power-generating coil wound around the magnetic core, the magnetic core, stator and rotor constituting a first magnetic circuit, and a part of the stator around and adjacent to the rotor constituting a second magnetic circuit; and

further comprising a protrusion projecting toward the rotor formed on the inner periphery of the rotor accommodation hole of the stator within an angular range of ±45° around a magnetic flux direction of the first magnetic circuit at a rotation center of the rotor; and

a processor actuated by an electric energy generated by the power generator.

7. A power generator comprising:

a rotor having a permanent magnet rotated by a transmitted rotary drive force;

a stator having a rotor accommodation hole, the rotor being disposed in the accommodation hole;

a magnetic core, and a power-generating coil wound around the magnetic core, the magnetic core, stator and rotor constituting a first magnetic circuit, and a part of the stator around and adjacent to the rotor constituting a second magnetic circuit; and

further comprising a protrusion projecting toward the rotor formed on the inner periphery of the rotor accommodation hole of the stator within an angular range of ±45° around a magnetic flux direction of the second magnetic circuit at a rotation center of the rotor.

8. The power generator according to claim 7 , wherein the protrusion is formed within an angular range of ±10° around the magnetic flux direction of the second magnetic circuit at the rotation center of the rotor.

9. The power generator according to claim 8 , wherein the protrusion is formed in the magnetic flux direction of the second magnetic circuit at the rotation center of the rotor.

10. The power generator according to claim 7 , further comprising an oscillating weight, and a power-generating gear train that provides said transmitted rotary drive force to the rotor by transmitting a rotation of the oscillating weight.

11. A timepiece comprising:

a power generator comprising:

a rotor having a permanent magnet rotated by a transmitted rotary drive force;

a stator having a rotor accommodation hole, the rotor being disposed in the accommodation hole;

a magnetic core, and a power-generating coil wound around the magnetic core, the magnetic core, stator and rotor constituting a first magnetic circuit, and a part of the stator around and adjacent to the rotor constituting a second magnetic circuit; and

further comprising a protrusion projecting toward the rotor formed on the inner periphery of the rotor accommodation hole of the stator within an angular range of ±45° around a magnetic flux direction of the second magnetic circuit at a rotation center of the rotor;

a time display; and

a processor for actuating said time display by an electric energy generated by the power generator.

12. An electronic device comprising:

a power generator comprising:

a rotor having a permanent magnet rotated by a transmitted rotary drive force;

a stator having a rotor accommodation hole, the rotor being disposed in the accommodation hole;

a magnetic core, and a power-generating coil wound around the magnetic core, the magnetic core, stator and rotor constituting a first magnetic circuit, and a part of the stator around and adjacent to the rotor constituting a second magnetic circuit; and

further comprising a protrusion projecting toward the rotor formed on the inner periphery of the rotor accommodation hole of the stator within an angular range of ±45° around a magnetic flux direction of the second magnetic circuit at a rotation center of the rotor; and

a processor actuated by an electric energy generated by the power generator.

Priority Claims (2)
JP 2000-000925 · Jan 6, 2000 · national
JP 2000-314283 · Oct 13, 2000 · national
Continuity (2)
Division 0975497000 · Jan 5, 2001
Related Publication 20030127919A1 · Jul 10, 2003