SOUND GENERATOR

• US 20190313192A1
• Filed: 06/21/2019
• Published: 10/10/2019
• Est. Priority Date: 01/26/2017
• Status: Active Grant

• Current Assignee: DENSO Electronics Corporation (DENSO Corporation)
• Original Assignee: Anden Company Limited (DENSO Corporation)
• Inventors: MIYATA, Susumu, HAYAKAWA, Koshiro
• Granted Patent: US 11,051,110 B2
• Time in Patent Office: Days
• CPC Class Codes: B60Q 5/00 Arrangement or adaptation of acoustic signal devices
• CPC Class Codes: H04R 1/00 Details of transducers, loudspeakers or microphones
• CPC Class Codes: H04R 1/02 Casings; Cabinets ; Supports therefor; Mountings therein H04R1/28 takes precedence ; attachments for microphones H04R1/08; mounting of transducers in earpieces H04R1/1075
• CPC Class Codes: H04R 1/023 Screens for loudspeakers
• CPC Class Codes: H04R 2400/11 Aspects regarding the frame of loudspeaker transducers
• CPC Class Codes: H04R 7/12 Non-planar diaphragms or cones
• CPC Class Codes: H04R 7/18 at the periphery
• CPC Class Codes: H04R 9/025 Magnetic circuit
• CPC Class Codes: H04R 9/04 Construction, mounting, or centering of coil
• CPC Class Codes: H04R 9/06 Loudspeakers

Abstract

A sound generator that generates sound by vibrating a diaphragm includes: a housing including a first space opened to the atmosphere by a sound emission hole and a second space separated from the first space by the diaphragm; and a shield plate disposed in the first space to face the diaphragm while being separated from the diaphragm. When the diaphragm is displaced toward the first space by a pressure difference between the first space and the second space, the diaphragm comes in contact with the shield plate to limit deformation of the diaphragm.

Claims

1. A sound generator that generates sound by vibrating a diaphragm, comprising:

a housing including a first space opened to an outside air through a sound emission hole and a second space separated from the first space by the diaphragm; and

a shield plate disposed in the first space to face the diaphragm while being separated from the diaphragm, wherein

when the diaphragm is displaced toward the first space by a pressure difference between the first space and the second space, the diaphragm comes in contact with the shield plate to limit deformation of the diaphragm.

2. The sound generator according to claim 1, wherein the shield plate has a shape corresponding to the diaphragm.

3. The sound generator according to claim 2, wherein

the diaphragm includes an inner peripheral portion convex toward the first space, and an outer peripheral portion inclined from an outer edge of the inner peripheral portion toward the first space, and

the shield plate includes an inner peripheral portion convex away from the diaphragm, and an outer peripheral portion inclined from an outer edge of the inner peripheral portion away from the diaphragm.

4. The sound generator according to claim 2, wherein

the diaphragm includes an inner peripheral portion convex toward the second space, and an outer peripheral portion inclined from an outer edge of the inner peripheral portion toward the first space, and

the shield plate includes an inner peripheral portion convex away from the diaphragm, and an outer peripheral portion inclined from an outer edge of the inner peripheral portion away from the diaphragm.

5. The sound generator according to claim 3, wherein

the outer peripheral portion of the diaphragm comes in contact with the outer peripheral portion of the shield plate to limit the deformation of the diaphragm.

6. The sound generator according to claim 3, wherein

the outer edge of the inner peripheral portion of the diaphragm comes in contact with the outer edge of the inner peripheral portion of the shield plate to limit the deformation of the diaphragm, and

when the deformation of the diaphragm is limited by the shield plate, a clearance is provided between the inner peripheral portion of the diaphragm and the inner peripheral portion of the shield plate.

7. The sound generator according to claim 3, wherein

the diaphragm includes an upright portion extending upright from the outer edge of the inner peripheral portion toward the second space, and

when the deformation of the diaphragm is limited by the shield plate, the diaphragm comes in contact with the shield plate at a portion where the upright portion is formed.

8. The sound generator according to claim 3, wherein

the outer edge of the inner peripheral portion of the shield plate has the same shape as the outer edge of the inner peripheral portion of the diaphragm.

9. The sound generator according to claim 8, wherein

the outer edge of the inner peripheral portion of the diaphragm has a circular shape, and

the outer edge of the inner peripheral portion of the shield plate has a circular shape equal in diameter to the outer edge of the inner peripheral portion of the diaphragm.

10. The sound generator according to claim 1, wherein a distance between the diaphragm and a contact surface of the shield plate which comes in contact with the diaphragm is set within a range between 1 mm and 6 mm.

11. The sound generator according to claim 1, further comprising a drive unit that vibrates the diaphragm, wherein

a distance between the diaphragm and a contact surface of the shield plate in contact with the diaphragm is greater than an amount of displacement of the diaphragm when the diaphragm is vibrated by the drive unit.

12. The sound generator according to claim 11, wherein the drive unit comprises:

a core portion of the diaphragm having a cylindrical shape projected toward the second space;

a voice coil that is wound around the core portion; and

a magnetic circuit unit in which a cylindrical space is defined coaxial with the core portion, to displace the core portion inside the cylindrical space by applying a magnetic field to the voice coil, wherein

the amount of displacement of the diaphragm, when the diaphragm is vibrated by the drive unit, is defined within a range to maintain the core portion to be located in the cylindrical space.

13. The sound generator according to claim 12, wherein the magnetic circuit unit comprises:

a magnet having one surface and the other surface;

a first magnetic portion connected to the one surface of the magnet; and

a second magnetic portion having

a bottom portion connected to the other surface of the magnet, and

a cylindrical portion projecting in the axial direction from an outer peripheral portion of the bottom portion, wherein

the cylindrical space is provided between the magnet and the first magnetic portion, and the cylindrical portion.

14. The sound generator according to claim 12, further comprising

a frame that secures the diaphragm, wherein

when the deformation of the diaphragm is limited by a contact between the shield plate and the diaphragm, an end portion of the core portion connected to the diaphragm is closer to an original position of the end portion than a portion of the diaphragm secured to the frame in the axial direction of the core portion.

15. The sound generator according to claim 1, wherein

when the pressure difference between the first space and the second space is reduced in a state where the deformation of the diaphragm is limited by the contact between the diaphragm and the shield plate, the diaphragm returns to an original shape or position by an own restoring force of the diaphragm.

16. The sound generator according to claim 12, wherein

when the deformation of the diaphragm is limited by the contact between the diaphragm and the shield plate, the core portion is located out of the cylindrical space, and

when the pressure difference between the first space and the second space is reduced in a state where the deformation of the diaphragm is limited by the contact between the diaphragm and the shield plate, the diaphragm returns to an original shape or position of the diaphragm by an own restoring force of the diaphragm, and the core portion returns to be located in the cylindrical space by return of the diaphragm to the original shape or position.