NON-CONTACT POWER TRANSMISSION APPARATUS

• US 20130175876A1
• Filed: 09/14/2011
• Published: 07/11/2013
• Est. Priority Date: 09/16/2010
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kiyota, Atsushi
• Granted Patent: US 9,093,216 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/366 made of ferromagnetic material
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters

Abstract

Provided is a non-contact power transmission apparatus that can be made thinner without any drop in power transmission efficiency.

The non-contact power transmission apparatus includes: primary coil (2) generating a magnetic flux (Φ1); secondary coil (4) disposed facing primary coil (2) to receive power in a non-contact manner from primary coil (2) by electromagnetic induction; magnetic-substance layer (5) that covers a side opposite the side of secondary coil (4) facing primary coil (2) so that the magnetic flux (Φ1) can pass; magnet portion (7) disposed to be able to switch two magnetic poles and configured to generate a magnetic flux (Φ2) that is larger than the difference between the maximum value of the first magnetic flux (Φ1) and the saturated magnetic flux of magnetic-substance layer (5) and that passes through magnetic-substance layer (5) in a direction in which magnetic-substance layer (5) spreads; and magnetic pole switching unit (8) that detects the direction of the first magnetic flux (Φ1), and switches the magnetic pole of magnet portion (7) to generate a magnetic flux (Φ2) in a direction opposite the direction of the first magnetic flux (Φ1).

Claims

1. A non-contact power transmission apparatus comprising:

a primary coil generating a magnetic flux;

a secondary coil disposed facing the primary coil to receive power in a non-contact manner from the primary coil by electromagnetic induction so that a magnetic flux of the primary coil can pass through the coil;

a magnetic-substance layer disposed to cover a side opposite a side of the secondary coil facing the primary coil so that the magnetic flux of the primary coil that passed through the secondary coil can pass;

a magnet portion disposed to be able to switch two magnetic poles and configured to generate a magnetic flux that is larger than a difference between the maximum value of the first magnetic flux generated at the primary coil and the saturated magnetic flux of the magnetic-substance layer and that passes through the magnetic-substance layer in a direction in which the magnetic-substance layer spreads; and

a magnetic pole switching unit that detects a direction of the first magnetic flux generated at the primary coil, and switches a magnetic pole of the magnet portion to generate a magnetic flux in a direction opposite the direction of the magnetic flux.

2. The non-contact power transmission apparatus according to claim 1, wherein:

the magnetic pole switching unit includes an electromagnet to switch the magnetic pole of the magnet portion by applying a magnetic force to the magnet portion;

the magnet portion is made of a resin material containing a powdered magnet; and

the resin material has enough viscosity to keep the magnet in a static state when no magnetic force is received from the magnetic pole switching unit, and rotate the magnet when a magnetic force is received from the magnetic pole switching unit.

3. The non-contact power transmission apparatus according to claim 2, wherein the magnetic pole switching unit includes a magnetic flux direction detection coil that detects the direction of the magnetic flux generated at the primary coil by electromagnetic induction.

4. The non-contact power transmission apparatus according to claim 1, further comprising a magnetic flux generation coil generating a magnetic flux toward the magnetic flux direction detection coil,

wherein the magnetic flux direction detection coil and the magnetic flux generation coil are arranged in positions not to be affected by the magnetic fluxes generated by the magnet portion and the electromagnet.