ACTUATOR AND ELECTRIC TOOTHBRUSH UTILIZING SAME

• US 20110214239A1
• Filed: 11/10/2009
• Published: 09/08/2011
• Est. Priority Date: 11/14/2008
• Status: Active Grant

• Current Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Original Assignee: Mitsumi Electric Co., Ltd. (MinebeaMitsumi Inc.)
• Inventors: Sakaguchi, Kazutaka, Kagami, Masaharu, Takahashi, Yuki, Inamoto, Shigenori
• Granted Patent: US 8,587,162 B2
• Time in Patent Office: Days
• US Class Current: 15/22.1
• CPC Class Codes: A61C 17/32 reciprocating or oscillating
• CPC Class Codes: A61C 17/34 driven by electric motor
• CPC Class Codes: A61C 17/3418 Rotation around the axis of the toothbrush handle
• CPC Class Codes: H02K 33/16 with polarised armatures moving in alternate directions by reversal or energisation of a single coil system

Abstract

Disclosed is an actuator that realizes reciprocal rotational motion of an electric toothbrush, for example, without utilizing a drive transmission mechanism that is separate from the drive source. In the actuator, a fixed body (120) has a coil (128) that is disposed around a magnet (160) and faces the magnetic planes with different polarities within the magnet (160) at individual prescribed distances, and an outer yoke (150) that covers the outer periphery of the coil (128). The fixed body (120) rotatably supports a movable body (110), which holds the magnet (160), via a coil spring that is an elastic member (130) made from a wire. An alternating current supplying part (140) supplies an alternating current having roughly the same resonance frequency as that of the fixed body (120) to the coil (128) to cause the movable body (110) to vibrate in a reciprocal rotational motion. The coil spring that is the elastic member (130) uniformly disperses stress generated by the vibration.

Claims

1. An actuator having:

an outer yoke having inner wall planes that are placed a predetermined interval apart opposing each other;

a permanent magnet that is placed to oppose the opposing inner wall planes over an air gap and that has different magnetic pole planes that oppose the inner wall planes respectively; and

a coil that is placed in the air gap and surrounds the permanent magnet, the actuator comprising;

a fixed body that has one of the permanent magnent and the coil;

a movable body that has the other one of the permanent magnet and the coil and that has an output shaft that is perpendicular to both a direction in which the magnetic pole planes and the inner wall planes oppose each other and an axial direction of winding of the coil;

an alternating current supplying section that supplies an alternating current of approximately a same frequency as a resonance frequency of the movable body to the coil; and

a linear elastic member that has its one end fixed to the fixed body and the other end fixed to the movable body, and that supports the movable body on the fixed body to be able to rotate about an axis along the output shaft.

2. The actuator according to claim 1, wherein the elastic member is a coil spring.

3. The actuator according to claim 2, wherein the coil spring as the elastic member connects the fixed body and the movable body such that an axial center of a winding part substantially matches an axial center of the output shaft.

4. The actuator according to claim 1, wherein the elastic member is a wire-shaped spring that is placed in a direction to cross the output shaft.

5. The actuator according to claim 1, wherein:

the movable body comprises the outer yoke and the permanent magnet that is provided in the outer yoke via a non-magnetic body; and

the fixed body comprises the coil.

6. The actuator according to claim 1, wherein:

the movable body comprises the coil; and

the fixed body comprises the outer yoke and the permanent magnet that is provided in the outer yoke via a non-magnetic body.

7. The actuator according to claim 1, wherein the movable body is axially supported on the fixed body to be able to rotate about the output shaft.

8. An electric toothbrush comprising:

the actuator of claim 1; and

a toothbrush part that is coaxially coupled with the output shaft of the actuator, at a head of the toothbrush part a hair bundle part being provided to be perpendicular to an axial direction.