Vibrator for bone-conduction hearing
The vibrator system is for generating bone conduction vibrations. A magnet ( 8 a ) provides a static magnetic flux (Φ 1 ) that follows a first path. A bobbin ( 4 a ) is disposed at a center a vibrator ( 2 ). A housing ( 10 ) encloses the bobbin and has a coil surrounding a center of the bobbin. The coil is powered by an alternating current for providing an alternating dynamic magnetic flux (Φ 2 ) following the first path through a magnetic circuit. The housing has an upper end ( 116 ). The upper end and the bobbin have a first gap ( 14 a ) formed therebetween. The housing has a lower end ( 118 ) opposite the upper end. The lower end and the bobbin have a second gap ( 14 b ) formed therebetween. The magnet is positioned so that the static magnetic flux (Φ 1 ) is passing through the first and second gaps in a direction substantially parallel with an axial direction (A) of the vibrator. Suspension means ( 16 a, 16 b ) are provided for suspending the bobbin in a center of the housing.
1. A vibrator system for generating bone conduction vibrations, comprising:
a housing having a magnet in a wall thereof and a vibrator disposed therein, the magnet providing a static magnetic flux (Φ 1 ) following a first path;
a bobbin being centered in the vibrator;
the housing enclosing the bobbin, the housing having a coil wound around a center portions of the bobbin, the coil being powered by an alternating current for providing an alternating dynamic magnetic flux (Φ 2 ) substantially following the first path through a magnetic circuit;
the housing having an upper end, the upper end and the bobbin having a first gap formed therebetween;
the housing having a lower end opposite the upper end, the lower end and the bobbin having a second gap formed therebetween;
the static magnetic flux (Φ 1 ) is passing through the first and second gaps in a direction substantially parallel with an axial direction (A) of the vibrator; the static magnetic flux (Φ 1 ) is not passing through any other gaps than the first and second gaps; and
suspension means for suspending the bobbin in a centered position inside the housing.
2. The vibrator system according to claim 1 , wherein the bobbin is substantially symmetrical in relation to an axial central plane of the vibrator.
3. The vibrator system according to claim 1 , wherein the coil is secured to the bobbin.
4. The vibrator system according to claim 1 , wherein the magnet is placed in the housing in an axial central plane of the vibrator.
5. The vibrator system according to claim 1 , wherein the housing has a mid-section that has a circumference that is greater than a circumference of distal ends and the magnet is attached to the mid-section.
6. The vibrator system according to claim 1 , wherein the bobbin is suspended in the vibrator housing with a suspension cushion.
7. The vibrator system according to claim 1 , wherein the dynamic magnetic flux (Φ 2 ) is switchable to flow in a first direction and a second opposite direction.
8. The vibrator system according to claim 7 , wherein the first direction is the same as a magnetic flow direction of the static magnetic flux (Φ 1 ).
9. The vibrator system according to claim 7 , wherein the second direction is opposite a magnetic flow direction of the static magnetic flux (Φ 1 ).
10. The vibrator system according to claim 1 , wherein the bobbin is suspended in a suspension spring positioned outside the housing.