DUAL AXIAL MAGNETIC FLUX INDUCTION SPEAKER

Abstract

The present invention relates to the operating principle of a loudspeaker (20) with an induction motor (10). The motor (10) has two magnets (1a and 1b) positioned on either side of a central core (2). The magnets (1a and 1b) thus create two magnetic fields (9a and 9b) doubling the magnetic field detected in the movable armature (4). The magnetic field coupled to the electrical field generated by a fixed coil (5) creates a force in the armature (4), which is linked to diaphragm (7) producing the sound. Thus, by increasing the magnetic field, and therefore the force generated in the armature (4), the performances of the loudspeaker (20) are likewise enhanced.

Claims

1. An induction motor device comprising a fixed coil, a mobile armature within a magnetic space, a central core, wherein it comprises at least two magnetic sources disposed axially on either side of the central core.

2. The induction motor device as claimed in claim 1, wherein the magnetic sources are opposing, thus creating two distinct magnetic fields.

3. The induction motor device as claimed in claim 1, wherein at least one of the magnetic sources comprises one or more bipolar permanent ring magnets.

4. The induction motor device as claimed in claim 1, wherein at least one of the magnetic sources comprises one or more disk-shaped bipolar permanent magnets.

5. The induction motor device as claimed in claim 1, wherein at least one of the magnetic sources comprises one or more bipolar permanent magnets taking the form of ring sections.

6. A loudspeaker comprising at least one device as claimed in claim 1.

7. The loudspeaker as claimed in claim 1, said loudspeaker comprising at least one diaphragm linked to the armature and caused to move by the armature.

8. The loudspeaker as claimed in claim 6, said loudspeaker comprising a salad bowl to which the diaphragm is fixed and a housing fixing the induction motor device to the salad bowl.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention and its advantages will become apparent in the description hereinbelow, with reference to the appended drawings, in which:

[0027] FIG. 1 shows a cross-sectional perspective view of the motor of the loudspeaker comprising the dual axial magnetic flux induction system according to one embodiment of the invention,

[0028] FIG. 2 shows a cross-sectional view of the loudspeaker comprising the motor with the dual axial magnetic induction system according to one embodiment of the invention,

[0029] FIG. 3 shows a cross-sectional perspective view of the loudspeaker comprising the motor with the dual axial magnetic induction system according to one embodiment of the invention,

[0030] FIG. 4 shows an exploded view of the loudspeaker, showing all of the components of the motor and of the loudspeaker according to one embodiment of the invention,

[0031] FIG. 5 shows a cross-sectional view of the motor with a dual axial magnetic induction system, and a representation of the magnetic fields modeled by arrows according to one embodiment of the invention,

[0032] FIG. 6a shows a ring-shaped magnet according to one embodiment of the invention,

[0033] FIG. 6b shows a magnet in the form of ring sections according to one embodiment of the invention,

[0034] FIG. 6c shows a disk-shaped magnet according to one embodiment of the invention,

[0035] FIG. 7a shows a cross-sectional perspective view of the loudspeaker comprising the induction motor composed of ring magnets according to one embodiment of the invention,

[0036] FIG. 7b shows a cross-sectional perspective view of the loudspeaker comprising the induction motor composed of magnets in the form of ring sections according to one embodiment of the invention,

[0037] FIG. 7c shows a cross-sectional and perspective view of the loudspeaker comprising the induction motor composed of disk-shaped magnets according to one embodiment of the invention.

DETAILED DESCRIPTION OF NON-LIMITING EMBODIMENTS OF THE INVENTION

[0038] With reference to the figures, the induction motor 10 of the loudspeaker 20 comprises a core 2, a bowl 3b and a base plate 3a, all three formed from a magnetically conducting material, preferably steel or another equivalent material; a fixed coil 5 installed inside of said bowl 3b and supplied with an AC current; two permanent magnets 1a, 1b, made of a highly magnetic material, preferably neodymium, an upper magnet 1a having a north face 11a and a south face 11b, and a lower magnet 1b having a north face 12a and a south face 12b.

[0039] Said induction motor 10 may be equipped with various shapes of magnets, such as ring magnets 1a and 1b shown in FIGS. 6a and 7a, magnets taking the form of ring sections such as the upper magnets in the form of ring sections 1c and the lower magnets in the form of ring sections 1d shown in FIGS. 6b and 7b, or else magnets in the form of disks such as the upper magnet in the form of a disk 1e and the lower magnet in the form of a disk 1f shown in FIGS. 6c and 7c. These examples are non-limiting but illustrative and other equivalent shapes are possible.

[0040] Said magnets are installed so as to have their said north faces, respectively 11a and 12a, in contact with said core 2, said south face of the upper magnet 11b in contact with said bowl 3b and said south face of the lower magnet 12b in contact with said base plate 3a, in such a manner as to form between said core 2, said upper magnet 1a, said lower magnet 1b, said bowl 3b, said base plate 3a and said fixed coil 5, a magnetic air space 6. Within said magnetic air space 6 an armature 4 is installed composed of a conductive material, preferably aluminum, and connected to a loudspeaker diaphragm 7. The attachment system for connecting the diaphragm 7 to the armature 4 may for example comprise tabs 21 of the armature 4 which are fixed to studs 22 of the diaphragm. Other equivalent means of attachment are possible, for example the bonding of the armature 4 to the diaphragm 7, an additional coupling element, clip-mounting, etc.

[0041] The assembly of said loudspeaker 20 illustrated in FIG. 2 comprises said induction motor 10, said diaphragm 7 fixed to the salad bowl 8a, and a loudspeaker housing 8b used to fix said motor 10 with said salad bowl 8a.

[0042] Said magnets 1a and 1b may also be installed in an opposing manner, with respectively said south faces 11b and 12b in contact with said core 2, without the principle of operation of said induction motor 10 being altered, in an equivalent construction.

[0043] Said ring magnets 1a and 1b may be replaced by magnets taking the form of ring sections 1c and 1d or in the form of a disk 1e and 1f such as illustrated in the present application.

[0044] With reference to FIG. 5, said upper magnets 1a and lower magnets 1b are positioned such that their poles in contact with said core 2 are the same. Said upper and lower magnets 1a and 1b create two distinct magnetic fields: an upper magnetic field 9a and a lower magnetic field 9b. Said upper magnetic field 9a, generated by said upper magnet 1a, firstly passes through said core 2, then said magnetic air space 6 from the inside to the outside and then interacts with said armature 4. It subsequently returns to said south face 11b of said upper magnet 1a through said fixed coil 5 and said bowl 3b. Said lower magnetic field 9b, generated by said lower magnet 1b, firstly passes through said core 2, then said magnetic air space 6, from the inside to the outside. It also interacts with said armature 4 then returns to said south face 12b of said lower magnet 1b via said fixed coil 5, said bowl 3b and said base plate 3a. Thus, within said magnetic air space 6, and notably in said armature 4, said magnetic fields 9a and 9b have the same direction and the same sense, which represents double the magnetic intensity with respect to a conventional induction system with a single radial magnetic flux.

[0045] Said magnetic fields 9a and 9b, coupled to the electric field generated by said fixed coil 5, create a force in said armature 4. This force drives the movement of said armature 4, linked to said diaphragm 7 for example by the means 21, 22 described hereinabove.

[0046] Thus, by increasing the intensity of the magnetic field experienced by said armature 4, the force applied to said armature 4 is increased and hence the performance characteristics of said loudspeaker 20 are enhanced.

[0047] The embodiments are described by way of illustrative examples and must not be considered as limiting. Other embodiments may call upon means equivalent to those described for example. The embodiments may also be combined together depending on the circumstances, or means used in one embodiment may be used in another embodiment.