Bone conduction device including a balanced electromagnetic actuator having radial and axial air gaps

Patent metadata

Field	Value
Publication number	US-10178484-B2
Application number	US-201615262786-A
Country	US
Kind code	B2
Filing date	Sep 12, 2016
Priority date	Mar 16, 2011
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A bone conduction device configured to couple to an abutment of an anchor system anchored to a recipient's skull. The bone conduction device includes a vibrating electromagnetic actuator configured to vibrate in response to sound signals received by the bone conduction device, and a coupling apparatus configured to attach the bone conduction device to the abutment so as to impart to the recipient's skull vibrations generated by the vibrating electromagnetic actuator. The vibrating electromagnetic actuator includes a bobbin assembly and a counterweight assembly. Two axial air gaps are located between the bobbin assembly and the counterweight assembly and two radial air gaps are located between the bobbin assembly and the counterweight assembly. No substantial amount of the dynamic magnetic flux passes through the radial air gaps.

First claim

What is claimed is:

1. A method of imparting vibrational energy, comprising: moving a first assembly relative to a second assembly in an oscillatory manner via interaction of a dynamic magnetic flux and a static magnetic flux; and directing a substantial amount of the dynamic magnetic flux to flow outside of a first air gap having a span that is constant with the movement of the first assembly relative to the second assembly, wherein the first assembly is supported by a spring that is connected to the second assembly and is a separate component from the first assembly and the second assembly.

2. The method of claim 1 , wherein: the first assembly includes a bobbin and a coil, the bobbin having a core, wherein the coil is wrapped around the core of the bobbin; the second assembly includes at least one permanent magnet; and the method further comprises: maintaining the span of the first air gap at a constant length during the oscillatory movement of the first assembly relative to the second assembly, thereby preventing magnetic saturation in the core of the bobbin.

3. A method of claim 2 , further comprising: receiving sound signals; converting the received sound signals into electrical signals; and moving the first assembly relative to the second assembly based on the electrical signals.

4. The method of claim 3 , further comprising: imparting vibrations to a skull of a recipient as a result of the movement of the first assembly relative to the second assembly.

5. The method of claim 1 , further comprising: directing the dynamic magnetic flux and the static magnetic flux through a second air gap having a span that is varying with the movement of the first assembly relative to the second assembly; and directing the static magnetic flux through the first air gap having the span that is constant with the movement of the first assembly relative to a second assembly.

6. The method of claim 1 , further comprising: directing the static magnetic flux through the first air gap having the span that is constant with the movement of the first assembly relative to a second assembly, wherein collective distance of the spans of all axial air gaps through which the static magnetic flux and the dynamic magnetic flux flow are substantially no more than a maximum distance of the generated relative movement of the second assembly to the first assembly.

7. The method of claim 1 , wherein: the action of moving the first assembly relative to the second assembly in an oscillatory manner results in a bone conduction hearing percept; and at least most of the first assembly and the second assembly are located above a skull surface when evoking a hearing percept.

8. The method of claim 1 , further comprising: capturing a sound; transducing the captured sound into an electrical signal; and generating the dynamic magnetic flux based on the electrical signal at a location outside of a skull.

9. The method of claim 1 , wherein: the first assembly is symmetrical at least about a plane that lies on and is parallel to a longitudinal axis of the first assembly.

10. The method of claim 1 , wherein: the second assembly is symmetrical at least about a plane that lies on and is parallel to a longitudinal axis of the second assembly.

11. The method of claim 1 , wherein: the second assembly includes a bobbin and a coil, the bobbin having a core, wherein the coil is wrapped around the core of the bobbin; the first assembly includes at least one permanent magnet spaced away from the first air gap, wherein the bobbin is at least substantially fixed in space while the first assembly moves relative to the second assembly.

12. The method of claim 1 , wherein the first air gap is a radial air gap that is located between the first assembly and the second assembly, and wherein during operation of the electromagnetic actuator the static magnetic flux flows through the radial air gap, and wherein no substantial amount of the dynamic magnetic flux flows through the radial air gap.

13. The method of claim 1 , wherein: the span that is constant is located at a top of the first and second assemblies relative to a bottom of the first and second assemblies; the span that is constant is established by respective parallel surfaces of the first and second assemblies; and the action of moving the first assembly relative to the second assembly results in the first assembly moving in a direction from the top to the bottom in a manner that at least one of the surfaces is fully shadowed by the other of the surface during the full range of downward movement.

14. The method of claim 1 , wherein: the span that is constant is established by respective parallel surfaces of the first and second assemblies that are respectively bounded by other respective surfaces that extend away from the respective surfaces of the parallel surfaces.

15. The method of claim 1 , wherein: at least one of the first assembly or the second assembly includes a permanent magnet that generates the static magnetic flux; and the permanent magnet does not establish a surface of the first air gap.

16. The method of claim 1 , wherein: surfaces of the first air gap are established by soft iron bodies.

17. The method of claim 1 , wherein: surfaces of the first air gap are established by a bobbin apparatus and a yoke.

18. The method of claim 1 , further comprising: directing the static magnetic flux through the first air gap having the span that is constant with the movement of the first assembly relative to a second assembly, wherein the first assembly and the second assembly comprise an actuator, and a cross-section of the actuator lying on a plane that is parallel to and lying on a longitudinal axis of the actuator has, on one side of the longitudinal axis, only two axial air gaps and only two radial air gaps.

19. A method of imparting vibrational energy, comprising: moving a first assembly relative to a second assembly in an oscillatory manner via interaction of a dynamic magnetic flux and a static magnetic flux; and directing a substantial amount of the dynamic magnetic flux to flow outside of a first air gap having a span that is constant with the movement of the first assembly relative to the second assembly, wherein the span that is constant is located at a bottom of the first and second assemblies relative to a top of the first and second assemblies; the span that is constant is established by respective parallel surfaces of the first and second assemblies; and the action of moving the first assembly relative to the second assembly results in the first assembly moving in a direction from the top to the bottom in a manner that at least one of the surfaces is fully shadowed by the other of the surface during the full range of downward movement.

20. The method of claim 19 , wherein: the first assembly is supported by a spring that is connected to the second assembly, and is a separate component from the first assembly and the second assembly.

21. The method of claim 19 , wherein: the span that is constant is established by respective parallel surfaces of the first and second assemblies that are respectively bounded by other respective surfaces that extend away from the respective surfaces of the parallel surfaces.

22. The method of claim 19 , wherein: the action of moving the first assembly relative to the second assembly in an oscillatory manner results in a bone conduction hearing percept; and most of the first assembly and the second assembly are located above a skull surface when evoking a hearing

Assignees

• Cochlear Ltd

Inventors

• Asnes Kristian

Classifications

• H04R25/606 Primary

  acting directly on the eardrum, the ossicles or the skull, e.g. mastoid, tooth, maxillary or mandibular bone, or mechanically stimulating the cochlea, e.g. at the oval window · CPC title

• H04R2460/13

  Hearing devices using bone conduction transducers · CPC title

• H04R9/066

  using the principle of inertia · CPC title

• H04R9/027

  Air gaps using a magnetic fluid · CPC title

• H04R2209/022

  Aspects regarding the stray flux internal or external to the magnetic circuit, e.g. shielding, shape of magnetic circuit, flux compensation coils · CPC title