Linear oscillator

• US 6,958,553 B2
• Filed: 07/03/2003
• Issued: 10/25/2005
• Est. Priority Date: 09/29/2000
• Status: Expired due to Fees

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Works Ltd (Panasonic Holdings Corporation)
• Inventors: Inoue, Hiroki, Yamada, Tomio, Hirata, Katsuhiro, Yabuuchi, Hidekazu, Arikawa, Yasushi, Ichii, Yoshitaka
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): Scheuermann, David W.
• Application Number:
  US10/611,905
• Publication Number:
  US 20040130221A1
• Time in Patent Office: 845 Days
• Field of Search: 335/262, 335/263, 335/223, 335/233, 335/235, 335/242, 310/12, 310/15, 310/17, 310/20, 310/23, 310/180, 310/181
• US Class Current: 310/15
• CPC Class Codes: A61C 17/34 driven by electric motor
• CPC Class Codes: A61C 17/3445 Translation along the axis of the toothbrush handle
• CPC Class Codes: B26B 19/282 Motors without a rotating central drive shaft, e.g. linear motors
• CPC Class Codes: H02K 33/16 with polarised armatures moving in alternate directions by reversal or energisation of a single coil system

Abstract

A linear oscillator includes a reciprocating moving part, a case to contain the moving part, and an amplitude control spindle moveably supported in the case. The moving part and the amplitude control spindle reciprocate at a frequency approximately equal to the resonance frequency of the linear oscillator.

Claims

1. A linear oscillator, comprising:

a reciprocatable moving part;

a case containing the moving part;

an amplitude control spindle moveably supported in the case;

an electromagnetic driving part housed in the case for reciprocating the moving part, wherein the electromagnetic driving part comprises;

at least one permanent magnet, and

at least one coil surrounding the moving part; and

a spring member disposed at least between the case and the moving part and between the case and the amplitude control spindle to form a spring oscillation system,

wherein the moving part and the amplitude control spindle reciprocate at or near to a resonance frequency of the linear oscillator.

2. The linear oscillator according to claim 1, wherein:

the spring member includes a coil spring, and

a mass of the amplitude control spindle including a first connecting element is larger than a mass of the moving part and a second connection element.

3. The linear oscillator according to claim 1, wherein the moving part and the amplitude control spindle reciprocate at approximately the resonance frequency in respectively opposite phases.

4. The linear oscillator according to claim 1, further comprising means for preventing rocking of the amplitude control spindle.

5. The linear oscillator according to claim 1, wherein the at least one coil is configured to be fed with a current to control the moving part and the amplitude control spindle when reciprocating.

6. The linear oscillator according to claim 5, wherein the coil is fixed to the case.

7. The linear oscillator according to claim 5, further comprising at least one yoke, wherein the at least one yoke is located between the coil and the at least one permanent magnet.

8. The linear oscillator according to claim 7, further comprising an air gap between the at least one permanent magnet and the case and between the at least one yoke and the case.

9. The linear oscillator according to claim 7, wherein at least one of said at least one yoke and said moving part is provided with means for reducing eddy current loss.

10. The linear oscillator according to claim 1, further comprising a shaft connected as a connection element to at least one of the moving part or the amplitude control spindle to output motion generated when the moving part and the amplitude control spindle reciprocate.

11. The linear oscillator according to claim 10, wherein the shaft is fixed to the amplitude control spindle.

12. The linear oscillator according to claim 10, wherein the shaft is fixed to the moving part and the amplitude control spindle surrounds partially or entirely the shaft.

13. The linear oscillator according to claim 12, wherein the moving part is located in an upper portion of the case, and the amplitude control spindle is located in a lower portion of the case, and the shaft traverses the case in the upper portion of the case and in the lower portion of the case.

14. The linear oscillator according to claim 10, wherein the shaft comprises a nonmagnetic substance.

15. The linear oscillator according to claim 14, wherein only a portion of the moving part passing through the shaft comprises a magnetic substance.

16. The linear oscillator according to claim 10, further comprising means for restricting an axial revolution of the shaft.

17. The linear oscillator according to claim 16, wherein the means for restricting includes the spring member.