MAGNETIC SPRING SYSTEM FOR USE IN A RESONANT MOTOR

• US 20100306934A1
• Filed: 11/18/2008
• Published: 12/09/2010
• Est. Priority Date: 12/19/2007
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Headstrom, Patrick
• Granted Patent: US 8,970,072 B2
• Time in Patent Office: Days
• US Class Current: 15/22.2
• CPC Class Codes: A61C 17/221 Control arrangements therefor
• CPC Class Codes: A61C 17/3445 Translation along the axis of the toothbrush handle
• CPC Class Codes: F16F 6/005 using permanent magnets only
• CPC Class Codes: H02K 33/06 with polarised armatures
• CPC Class Codes: H02K 33/16 with polarised armatures moving in alternate directions by reversal or energisation of a single coil system

Abstract

A magnetic spring arrangement for a resonant motor, comprising: a housing (12), magnets (14, 16) fixed in position at opposing ends (13, 15) of the housing, a magnet (18) positioned within the housing for movement toward and away from the fixed magnets in a reciprocal oscillating motion with a driving action produced by a stator coil (24) and an AC drive signal (26), wherein an applicator member (32) is attachable to the moving magnet for corresponding movement of a workpiece portion (34) of the applicator member.

Claims

1. A resonant linear motor, using a magnetic spring system, comprising:

a housing (12);

two permanent magnets (14, 16) fixedly positioned at opposing ends (13, 15) of the housing; and

at least one permanent magnet (18) positioned in the housing for movement toward and away from each end magnet in a reciprocal oscillating motion, wherein the polarities of the moving magnet oppose the polarities of the fixed magnets, wherein a workpiece assembly (32) is attachable to the moving magnet, and extends out through one of the fixed magnets, for linear movement thereof, in response to a driving action for the motor.

2. The motor of claim 1, wherein the linear motor includes a drive assembly which comprises a coil (24) wrapped around the exterior of the housing and an AC drive signal source (26) connected to the coil.

3. The motor of claim 2, wherein the frequency of the AC signal is approximately the same as the resonant frequency of the spring mass portion of the motor.

4. The motor of claim 1, including a linear bearing (22) between the moving magnet and the housing.

5. The motor of claim 1, wherein one of the fixed magnets is a ring magnet (29) through which the workpiece assembly extends.

6. The motor of claim 5, wherein the workpiece assembly includes a brushhead (34) for cleaning of teeth.

7. The motor of claim 1, including a second magnet (44) positioned within the housing for reciprocal, oscillating movement therein along with the first moving magnet (42), wherein the first and second moving magnets have opposing polarities, such that, in operation of the motor, vibration otherwise produced by movement of the moving magnets is substantially cancelled.

8. A resonant motor using a magnetic spring system for oscillating rotational action, comprising:

a housing;

a center element (50, 66, 84, 122) mounted for rotation about a central axis, the center element having magnets (52, 54, 68, 70;

88, 90;

118, 120) positioned on opposing PORTIONS thereof with opposing polarities facing outwardly therefrom, wherein the center element has a workpiece assembly extending therefrom for rotational action of the workpiece;

fixed magnets (58, 60;

76-79;

96, 98;

112, 114) positioned adjacent an outer surface of the center element; and

a drive assembly with an AC drive signal for driving the center element, wherein the polarities and the position of the fixed magnets are such relative to the polarities of the magnets on the center element, that there is a magnetic interaction between the fixed magnets and the mounted magnets, resulting in an oscillation of the center element, the motor characterized by the absence of mechanical springs.

9. The motor of claim 8, wherein the workpiece is a brushhead for cleaning teeth.

10. The motor of claim 8, wherein the magnetic interaction is attraction.

11. The motor of claim 8, wherein the magnetic interaction is repulsion.

12. The motor of claim 8, wherein the fixed magnets and the mounted magnets are positioned in a radial relationship.

13. The motor of claim 8, wherein the fixed magnets and the mounted magnets are positioned in an axial relationship.

14. The motor of claim 12, wherein the center element (84) is threaded over at least a portion of its length, with an exterior fixed nut (102) which engages the center element threads so as to permit a full rotation of the center element against the repulsion of the fixed magnets relative to the mounted magnets.

15. The motor of claim 8, wherein the center element includes a first plate (116) at one end thereof, with magnets (118, 120) on opposing portions thereof, and wherein fixed magnets (112, 114) are mounted on opposing portions of an adjacent second plate (110) which is fixedly mounted to the housing, wherein the magnets on the first plate are positioned such that the polarities thereof are (1) the same as or (2) opposite from the polarities of the magnets on the second plate.