Linear oscillator

• US 6,873,067 B2
• Filed: 06/18/2001
• Issued: 03/29/2005
• Est. Priority Date: 09/29/2000
• Status: Expired due to Fees

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: Inoue, Hiroki, Yamada, Tomio, Hirata, Katsuhiro, Yabuuchi, Hidekazu, Arikawa, Yasushi, Ichii, Yoshitaka
• Primary Examiner(s): Tamai, Karl
• Assistant Examiner(s): Scheuermann, David W.
• Application Number:
  US09/881,693
• Publication Number:
  US 20020195884A1
• Time in Patent Office: 1,380 Days
• Field of Search: 335/262, 335/263, 335/223, 335/233, 335/235, 335/242, 335/267, 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 moving part reciprocating;

a case containing incorporating said moving part; and

an amplitude control spindle supported in said case to be movable,

wherein said moving part and said amplitude control spindle reciprocate at a resonance frequency of said linear oscillator or a frequency in a vicinity thereof;

an electromagnetic driving part housed in said case, for reciprocating said moving part; and

a spring member disposed at least between said case and said moving part, and between said case and said amplitude control spindle, for forming a spring oscillation system,

wherein a resonance frequency of said spring oscillation system is equal to a resonance frequency of said linear oscillator or a frequency in a vicinity thereof,

wherein said spring member includes;

a first spring disposed between a fixed part comprised of said case and said electromagnetic driving part and said moving part;

a second spring disposed between said moving part and said amplitude control spindle; and

a third spring disposed between said amplitude control spindle and said fixed part.

2. The linear oscillator according to claim 1, wherein said second spring is stronger in spring force than said first and third springs.

3. A linear oscillator comprising:

a moving part reciprocating;

a case containing incorporating said moving part; and

an amplitude control spindle supported in said case to be movable

wherein said moving part and said amplitude control spindle reciprocate at a resonance frequency of said linear oscillator or a frequency in a vicinity thereof;

an electromagnetic driving part housed in said case, for reciprocating said moving part; and

a spring member disposed at least between said case and said moving part, and between said case and said amplitude control spindle, for forming a spring oscillation system,

wherein a resonance frequency ef said spring oscillation system is equal to a resonance frequency of said linear oscillator or a frequency in a vicinity thereof;

wherein;

said spring member is formed of a leaf spring; and

mass of said amplitude control spindle and a connection element thereof is smaller than mass of said moving part and an element thereof.

4. A linear oscillator comprising:

a moving part reciprocating;

a case containing incorporating said moving part; and

an amplitude control spindle supported in said case to be movable,

wherein said moving part and said amplitude control spindle reciprocal, at a resonance frequency of said linear oscillator or a frequency in a vicinity thereof;

an electromagnetic driving part housed in said case, for reciprocating said moving part; and

a spring member disposed at least between said ease and said moving part, and between said case and said amplitude control spindle, for forming a spring oscillation system,

wherein a resonance frequency of said spring oscillation system is equal to a resonance frequency of said linear oscillator or a frequency in a vicinity thereof,

wherein said electromagnetic driving part includes a coil to thereby use a coil current, thus enabling controlling a reciprocating motion,

wherein said electromagnetic driving part includes;

a coil surrounding an outer periphery of said moving part;

second yokes each disposed at each of both ends of said coil;

a pair of permanent magnets which are each disposed on an end face of each of said second yokes and which are magnetized symmetrically with respect to a center of said coil; and

first yokes provided on sides of said permanent magnets opposite to said second yokes respectively.

5. The linear oscillator according to claim 4, wherein at least a portion of said case facing said electromagnetic driving part is made of a magnetic substance and a thickness of a magnetic substance facing said electromagnetic driving part is 7% or more of an outer diameter of said permanent magnets.

6. The linear oscillator according to claim 4, wherein magnetic flux increasing means is provided for increasing a quantity of magnetic flux running toward said moving part.

7. The linear oscillator according to claim 4, wherein said first yokes each have a triangular cross section having a side facing said case being a slope.

8. The linear oscillator according to claim 4, wherein said yokes or said moving part are provided with eddy current loss reducing means for reducing an eddy current loss.

9. The linear oscillator according to claim 8, wherein said moving part has a alit formed therein in an amplitude direction.

10. The linear oscillator according to claim 4, wherein said moving part has a large diameter portion at both ends thereof in a reciprocating direction thereof and a small diameter portion at a center thereof in such a configuration that a boundary between said large diameter portion and said small diameter portion may roughly agrees with an end face of said second yoke on a side of said coil and that both end faces of said moving part in a reciprocating direction roughly agree with end faces of said permanent magnets on sides of eaid first yokes.

11. The linear oscillator according to claim 4, wherein a gap between an outer peripheral surface of said moving part and an inner peripheral surface of said yokes is non-uniform in an revolutionary direction.