Linear device and electric device with linear motor

Patent metadata

Field	Value
Publication number	US-9806591-B2
Application number	US-201313939198-A
Country	US
Kind code	B2
Filing date	Jul 11, 2013
Priority date	Jul 13, 2012
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A linear motor is disclosed. The linear motor includes an armature mounted for driven linear oscillation substantially along a longitudinal direction; a secondary mass mounted for linear oscillation substantially along the longitudinal direction; and a coupling unit for coupling the armature and the secondary mass. The coupling unit includes at least two coupling spring assemblies and at least a coupling element, the coupling spring assemblies being arranged in planes perpendicular to the longitudinal direction and being spaced apart from each other, and the coupling element being fixedly connected with the coupling spring assemblies.

First claim

The invention claimed is:

1. An oral hygiene device with a resonant linear motor for providing a linear oscillatory movement along a longitudinal direction comprising:
a housing;
a stator comprising a coil core and a stator coil wound around the coil core, which stator is fixedly mounted at or with respect to the housing;
an armature comprising a permanent magnet arrangement, which armature is mounted for linear oscillatory movement along the longitudinal direction relative to the stator, wherein the permanent magnet arrangement is arranged asymmetrically with respect to the longitudinal axis and has a free end surface facing one side of the stator; and
a drive shaft coupled with the armature, the drive shaft centrically extending along a longitudinal axis parallel to the longitudinal direction;
wherein the armature has two opposite end sections that are disposed at the longitudinal axis and a central section carrying the permanent magnet arrangement, which central section is offset from the longitudinal axis,
wherein the resonant linear motor comprises a secondary mass mounted within the housing for linear oscillation along the longitudinal axis to reduce or cancel vibrations transferred from the armature to the housing, and a coupling unit for coupling the armature and the secondary mass, wherein the coupling unit comprises at least two spring assemblies and at least one coupling element, the spring assemblies being arranged in planes substantially perpendicular to the longitudinal direction and being spaced apart from one another, and the coupling element being fixedly connected to the spring assemblies.

2. The oral hygiene device according to claim 1 , wherein the stator has at least one stator leg having an end face arranged to face the free end surface of the permanent magnet arrangement.

3. The oral hygiene device according to claim 2 , wherein an air gap extends between the end surface of the stator leg and the end surface of the permanent magnet arrangement, which air gap is arranged close to the longitudinal axis, wherein a distance between a center line of the air gap and the longitudinal axis is below about 2.0 mm.

4. The oral hygiene device according to claim 3 , wherein the minimal height of the air gap measured between the end surface of the stator leg and the end surface of the permanent magnet arrangement in a direction perpendicular to the longitudinal direction is in a range of between about 0.1 mm and about 0.6 mm.

5. The oral hygiene device according to claim 1 , wherein the stator is arranged only opposite to the permanent magnet arrangement.

6. The oral hygiene device according to claim 1 , wherein the armature is mounted via first and second armature mounting spring assemblies, wherein each of the armature mounting spring assemblies comprises at least one flat leaf spring.

7. The oral hygiene device according to claim 6 , wherein the armature is only borne by the armature mounting spring assemblies.

8. The oral hygiene device according to claim 6 , wherein the first and the second armature mounting spring assemblies are each arranged to extend in a plane perpendicular to the longitudinal direction and the armature and the stator are shaped such that they essentially fit into an area defined by the first and second mounting spring assemblies when viewed along the longitudinal direction.

9. The oral hygiene device according to claim 1 , wherein the resonant linear motor further comprises a secondary mass unit mounted for linear oscillation along the longitudinal direction.

10. The oral hygiene device according to claim 1 , wherein at least one of the spring assemblies is fixedly connected to the armature and at least one other of the coupling spring assemblies is fixedly connected to the secondary mass.

11. The oral hygiene device according to claim 1 , wherein the secondary mass is approximately identical to a mass of the armature.

12. The oral hygiene device according to claim 11 , wherein the mass of the coupling element is at least a factor 10 lower than the mass of the armature or the secondary mass.

13. The oral hygiene device according to claim 1 , wherein the armature is borne by at least a first armature-mounting spring assembly and the secondary mass is borne by at least a second mass-mounting spring assembly, and wherein all spring assemblies have essentially identical shape and are mounted with a same orientation.

14. The oral hygiene device according to claim 1 , wherein each of the spring assemblies comprises a flat leaf spring having an inner fastening section, an outer fastening section, and a spring arm connecting the inner fastening section and the outer fastening section, wherein the flat leaf spring is made from a single sheet such that the inner fastening section, the spring arm, and the outer fastening section are integral with one another, wherein the spring arm spirals around a center of area of the inner fastening section and the flat leaf spring is oblate in its plane of extension such that a ratio between a width of the leaf spring and a height of the flat leaf spring has a value of at least about 1.33, the direction in which the height is measured being perpendicular to the direction in which the width is measured.

15. The oral hygiene device according to claim 14 , wherein the spring arm spirals around the center of area of the inner fastening section over an angular range of at least about 360 degree.

16. The oral hygiene device according to claim 14 , wherein the center of the inner fastening section is positioned asymmetrically with respect to a height of the spring and symmetrically with respect to a width of the spring.

Assignees

• Braun Gmbh

Inventors

• Schober Uwe
• Ziegler Frank
• Schaefer Robert

Classifications

• F16F1/18

  Leaf springs {(planar springs in general F16F1/027; "Belleville"-type springs with generally radial arms F16F1/324)} · CPC title

• H02K33/16 Primary

  with polarised armatures moving in alternate directions by reversal or energisation of a single coil system · CPC title

• A61C17/3436

  Rotation around the axis perpendicular to the plane defined by the bristle holder · CPC title

• H02K33/00 Primary

  Motors with reciprocating, oscillating or vibrating magnet, armature or coil system (arrangements for handling mechanical energy structurally associated with motors H02K7/00, e.g. H02K7/06) · CPC title

• A61C17/225

  Handles or details thereof · CPC title