Magnet assembly

Abstract

The present invention provides a receiver comprising a housing, an armature, and a magnet assembly, where the armature and the magnet assembly are arranged in the housing. The magnet assembly comprises a magnet and a magnet shell. The magnet shell forms an inner space in which the magnet is provided, and where at least a part of the armature extends in the inner space. The magnet shell comprises at least two shell parts forming an inner surface encircling the inner space, where each of the shell parts comprises a first and a second end face. The first end face of a first shell part abuts one of the first and second end faces of an adjacent shell part, and the second end face of the first shell part abuts one of the first and second ends faces of an adjacent shell part.

Claims

1. A receiver comprising a housing, an armature, and a magnet assembly, the armature and the magnet assembly being arranged in the housing, the magnet assembly comprising a magnet and a magnet shell, the magnet shell forming an inner space in which the magnet is provided, wherein at least a part of the armature extends in the inner space, wherein the magnet shell comprises at least two shell parts forming an inner surface substantially encircling the inner space, and wherein the shell parts each comprises a first and a second end face, and the first end face of a first shell part abuts one of the first and second end faces of an adjacent shell part, the second end face of the first shell part abuts one of the first and second ends faces of an adjacent shell part.

2. A receiver according to claim 1, wherein each shell part further comprises an outer surface part and an inner surface part, the end faces forming an edge arranged in the transition between the outer surface part and the inner surface part, wherein each outer surface part forms part of the outer surface of the magnet shell and each inner surface part forms part of the inner surface encircling the inner space, when each end face of a shell part abuts an end face of an adjacent shell part.

3. A receiver according to claim 2, wherein the magnet comprises a first magnet portion and a second magnet portion, the first magnet portion and the second magnet portion being attached to different shell parts.

4. A magnet assembly for a receiver according to claim 2, the magnet assembly comprising a magnet and a magnet shell, the magnet shell forming an inner space in which the magnet is provided, wherein the magnet shell comprises at least two shell parts forming an inner surface substantially encircling the inner space, and wherein the shell parts each comprises a first and a second end face, and the first end face of a first shell part abuts one of the first and second end faces of an adjacent shell part, the second end face of the first shell part abuts one of the first and second ends faces of an adjacent shell part.

5. A receiver according to claim 1, further comprising an alignment structure for alignment of the at least two shell parts.

6. A receiver according to claim 5, wherein the alignment structure forms part of the magnet shell.

7. A receiver according to claim 6, wherein the alignment structure comprises an indentation formed at an end portion of at least one of the shell parts, the indentation forming a shape matching a shape of an end portion of another shell part.

8. A receiver according to claim 5, wherein the alignment structure comprises an indentation formed at an end portion of at least one of the shell parts, the indentation forming a shape matching a shape of an end portion of another shell part.

9. A receiver according to claim 5, wherein the alignment structure comprises a geometrical locking structure forming part of the shell parts.

10. A receiver according to claim 1, wherein the magnet comprises a first magnet portion and a second magnet portion, the first magnet portion and the second magnet portion being attached to different shell parts.

11. A receiver according to claim 1, wherein the shell parts have a thickness being a distance from the inner surface to an opposite outer surface, the thickness being non-uniform along the inner space.

12. A method of manufacturing a magnet assembly according to claim 1, the method comprising the step of; providing a magnet, providing at least two shell parts each comprising a first and a second end face, providing a housing, providing an armature, assembling the at least two shell parts to form a magnet shell having an inner space with an inner surface substantially encircling the inner space, so that the first end face of a first shell part abuts one of the first and second end faces of an adjacent shell part, and the second end face of the first shell part abuts one of the first and second end faces of an adjacent shell part, attaching the magnet to at least one of the shell parts, and arranging the magnet shell and the armature in the housing.

13. A method according to claim 12, wherein the step of attaching the magnet to at least one of the shell parts is carried out prior to assembling the shell parts to form a magnet shell.

14. A method according to claim 13, wherein the step of attaching the magnet comprises a step of attaching a first magnet portion to a first shell part and a step of attaching a second magnet portion to a second shell part.

15. A method according to claim 13, comprising a step of magnetizing the magnet prior to the step of assembling the magnet shell.

16. A method according to claim 13, wherein the magnet is attached to one of the shell parts prior to a step of releasing the shell part from a carrier material to which it is attached during manufacturing of the shell part.

17. A method according to claim 12, comprising a step of magnetizing the magnet prior to the step of assembling the magnet shell.

18. A method according to claim 12, wherein the step of assembling the magnet shell comprises a step of gluing the shell parts together.

19. A method according to claim 12, wherein the magnet is attached to one of the shell parts prior to a step of releasing the shell part from a carrier material to which it is attached during manufacturing of the shell part.

20. A magnet assembly for a receiver according to claim 1, the magnet assembly comprising a magnet and a magnet shell, the magnet shell forming an inner space in which the magnet is provided, wherein the magnet shell comprises at least two shell parts forming an inner surface substantially encircling the inner space, and wherein the shell parts each comprises a first and a second end face, and the first end face of a first shell part abuts one of the first and second end faces of an adjacent shell part, the second end face of the first shell part abuts one of the first and second ends faces of an adjacent shell part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be further described with reference to the drawings, in which:

(2) FIGS. 1A-1B illustrate two different views of an embodiment of a magnet assembly and an armature,

(3) FIGS. 2A-2E illustrate different views of an embodiment of a magnet assembly, an armature, and a coil,

(4) FIGS. 3A-3Q illustrate different embodiments of a magnet assembly, and

(5) FIG. 4 illustrates a further alternative of an embodiment of a magnet assembly.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) It should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

(7) FIGS. 1A-1B illustrate two different views of an embodiment of a magnet assembly 1 and an armature 2 for a receiver having a housing 100 (shown in FIG. 1B). The magnet assembly 1 comprises a magnet 4A, 4B and a magnet shell 5. The magnet shell 5 forms an inner space 6 in which the magnet 4A, 4B is provided.

(8) The magnet shell 5 comprises in the illustrated embodiment two shell parts 5A, 5B forming a common inner surface 7 encircling the inner space 6.

(9) The magnet shell 5 may comprises a protecting layer (not shown) arranged on the outer surface of the magnet shell. The protecting layer, e.g. a copper layer, may be arranged to reduce electromagnetic radiation from the magnet assembly 1.

(10) The armature is U-shaped and a first leg 8 extends through the inner space 6 formed by the magnet shell 5. A second leg 9 of the U-shaped armature extends substantially parallel to the first leg 8.

(11) The receiver may further comprise a diaphragm (not shown) which is operationally attached to the armature 2, such that movement of the armature 2 is transferred to the diaphragm 10. The receiver may comprise a drive pin operatively attaching the diaphragm to the armature 2. Movement of the diaphragm will cause sound waves to be generated.

(12) FIGS. 2A-2D illustrate different views of an alternative embodiment of a magnet assembly 101, a T-shaped armature 102, and a coil 112. The magnet assembly 101 comprises a magnet 104 and two shell parts 105A, 105B forming a common inner surface 107 encircling an inner space 106.

(13) FIG. 2A illustrates the different elements unassembled. In FIG. 2B, the two shell parts 105A, 105B are assembled to form the common inner surface 107 encircling the inner space 106.

(14) The shell parts 105A, 105B may comprises a protecting layer (not shown) arranged on the outer surface of the magnet shell; i.e. a protective layer may be arranged on top of the upper shell part 105A and on the bottom of the lower shell part 105B. The protecting layer, e.g. a copper layer, may be arranged to reduce electromagnetic radiation from the magnet assembly 105.

(15) The protective layer 105A arranged at the upper shell part 105A is illustrated by the hatching in FIG. 2E. It should be understood, that the protective layer may be a primer, a nano-coating, a copper layer, or another shielding material.

(16) The shell parts 105A, 105B each comprises a first joining surface 113 and a second joining surface 114. When assembling the magnet shell 105, the first joining surface 113A of the first shell part 105A abut the first joining surface 113B of the second shell part 105B, and second joining surface 114A of the first shell part 105A abuts the second joining surface 114B of a second shell part 105B. The joining surfaces 113, 114 may as an example be brought together by pressing and deforming the material, such as metals, from which the shell parts 105A, 105B are made.

(17) In FIG. 2C, the coil 112 has been inserted into the inner space 106 formed by the two shell parts 105A, 105B.

(18) The T-shaped 102 armature comprises two elongated parts, each part extending from a first end to a second end. The lower elongated part is connected to the upper elongated part substantially at the middle of the upper elongated part.

(19) In FIG. 2D, the T-shaped armature 102 has been inserted into the inner space 106 formed by the two shell parts 105A, 105B so that the lower part extends through the inner space 106 whereby an end portion 102A extends on the opposite side of the inner space. A drive pin can be attached to the end portions 102A.

(20) The upper part of the T-shaped armature is supported at least partly by the shell part 105B, whereby at least a part of the upper part of the T-shaped armature 102 is arranged in contact with the shell part 105B as also illustrated in FIG. 2D.

(21) FIGS. 3A-3M illustrate different embodiments of a magnet assembly 201, 301, 401, 501, 601, 701, 801.

(22) In FIG. 3A, the magnet assembly 201 comprises a magnet 204 comprising two magnet portions 204A, 204B and two shell parts 205A, 205B forming a common inner surface 207 encircling an inner space 206.

(23) The shell parts 205A, 205B each comprises a first end face 213 and a second end face 214. The end faces 213, 214 abut each other in a joint 215 being parallel to the magnet portions 204A, 204B substantially centrally in a direction along the height of the magnet assembly 201.

(24) In the illustrated embodiment, the shell parts 205A, 205B are substantially identical, both being U-shaped.

(25) In FIG. 3B, the magnet assembly 301 comprises two magnet portions 304A, 304B and two shell parts 305A, 305B forming a common inner surface 307 encircling an inner space 306.

(26) In the illustrated embodiment, the shell parts 305A, 305B are of different shape, as the upper shell part 305A is a substantially flat element, whereas the lower shell part 305B is U-shaped.

(27) The shell parts 305A, 305B each comprises a first end face 313 and a second end face 314. The end faces 313, 314 abut each other in a joint 315 being parallel to the magnet portions 304A, 304B along the lower surface of the upper shell part 305A.

(28) In FIG. 3C, the magnet assembly 401 is similar to the embodiment of FIG. 3A. However, the end faces 413, 414 abut each other in a joint 415 being transverse to the magnet portions 404A, 404B substantially centrally in a direction along the height of the magnet assembly 401.

(29) By providing the end faces 413, 414 so that they extend transverse to the shell parts 405A, 405B, the area of the end faces is larger whereby the area of the joint 415 are larger than the area of the joint 215 of the embodiment illustrated in FIG. 3A.

(30) In FIG. 3D, the magnet assembly 501 comprises two magnet portions 504A, 504B and two shell parts 505A, 505B forming a common inner surface 507 encircling an inner space 506.

(31) In the illustrated embodiment, the shell parts 505A, 505B are substantially identical. The end faces 513, 514 are formed at a portion of the shell parts 505A, 505B extending toward the centre of the inner space 506.

(32) In FIG. 3E, the magnet assembly 601 is similar to the embodiments illustrated in FIGS. 3A and 3C. However, the end faces 613, 614 abut each other in a joint 615 substantially centrally in a direction along the height of the magnet assembly 601.

(33) The end faces 613, 614 are each provided with a plurality of teeth 616, 617 which form a geometrically locking structure keeping the two shell parts 605A, 605B in a fixed position relative to each other. The teeth 616 of the upper shell part 605A are inserted into spaces of the lower shell part 605B, whereas the teeth 617 of the lower shell part 605B are inserted into spaces of the upper shell part 605A.

(34) In FIG. 3F, the magnet assembly 701 is similar to the embodiments illustrated in FIGS. 3A, 3C, and 3E. However, the shell parts 705A, 705B which abut each other in a joint 715 substantially centrally in a direction along the height of the magnet assembly 701 each forms a step-shaped end portion 713, 714 thereby forming a geometrically locking structure which partly fixes the two shell parts 705A, 705B to each other.

(35) In FIG. 3G, the magnet assembly 801 comprises two magnet portions 804A, 804B and two shell parts 805A, 805B forming a common inner surface 807 encircling an inner space 806.

(36) In the illustrated embodiment, the shell parts 805A, 805B are substantially identical, both being U-shaped.

(37) However, instead of joining the shell parts 805A, 805B at the first and second end faces, the shell parts 805A, 805B are inserted into each other, so that one leg 818 of each of the U-shaped shell parts 805 is located in the inner space, and so that the other leg 819 is located outside the inner space 806. The overlapping areas along the legs 818, 819 increase the connection area of the two shell parts 805A, 805B.

(38) FIG. 3H, the magnet assembly 901 comprises two magnet portions 904A, 904B and two shell parts 905A, 905B forming a common inner surface 907 encircling an inner space 906. At one side, the magnet shell 905 is assembled by inserting one leg 918 of the U-shaped shell part 905B in the inner space, and by locating one leg 919 of the U-shaped shell part 905A outside the inner space 906. At the other side, the magnet shell 905 is assembled at the end faces 913A which extend away from the inner space 906.

(39) FIGS. 3I and 3J illustrate two similar embodiments of a magnet assembly 1001, 1101 each comprising two L-shaped shell parts 1005A, 1005B, 1105A, 1105B. The embodiment 1101 illustrated in FIG. 3I comprises two L-shaped shell part 1005A, 1005B of same size, whereas one of the L-shaped shell parts 1105A in FIG. 3J is larger than the other L-shaped shell part 1105B. By provided the L-shaped shell parts 1105A, 1105B of different size, the shape may assist when assembling the shell parts since they are at least partly self-assigning.

(40) In FIG. 3K, the magnet assembly 1201 is similar to the embodiment illustrated in FIG. 3G. However, the thickness of the legs 1218, 1219 are approximately only half the thickness of the legs 818, 819 thereby reducing the total thickness of the magnet shell 1205 in the overlap between the legs 1218, 1219.

(41) In FIG. 3L, the magnet assembly 1301 is similar to the embodiment illustrated in FIG. 3H. However, the thickness of the legs 1318, 1319 are approximately only half the thickness of the legs 918, 919 thereby reducing the total thickness of the magnet shell 1305 in the overlap between the legs 1318, 1319 at the right side of the magnet shell 1305.

(42) In FIG. 3M, the magnet assembly 1401 is similar to the embodiment illustrated in FIG. 3I. However, at one of the end parts the thickness of the shell parts 1405A, 1405B is reduced to approximately half the thickness of the remaining shell part. The reduced thickness will facilitate alignment of the two shell parts 1405A, 1405B as the other end part will fit into the indentation provided by the reduced thickness.

(43) In FIG. 3N, the magnet assembly 1501 is similar to the embodiment illustrated in FIG. 3J. However, at one end part the thickness of the shell part 1505A is reduced to approximately half the thickness of the remaining shell part. The reduced thickness will facilitate alignment of the two shell parts 1505A, 1505B as one end part of the shell part 1505B will fit into the indentation provided by the reduced thickness of the shell part 1505A.

(44) In FIG. 3O, the magnet assembly 1601 is similar to the embodiment illustrated in FIG. 3A. However, the end faces 1613, 1614 abut each other in joints 1615, 1615 at different heights of the magnet assembly 601, since the legs 1618, 1619 are of different length. When assembled as illustrated in FIG. 3O, the assembled magnet assembly 1601 is identical to the magnet assembly illustrated in FIG. 3A.

(45) However, if the lower a shell part 1605B is rotated 180 degrees as indicated by the arrow A, the two long legs 1619 will join each other, while the two short legs 1618 will join each other. This will change the effective distance between the magnet portions 1604A, 1604B and thereby the magnet characteristics of the magnet assembly.

(46) In FIG. 3P, the magnet assembly 1701 is similar to the embodiment illustrated in FIG. 3A. However, the end faces 1713, 1714 abut each other in a joint 1715 being arranged substantially centrally along the width of the magnet portions 1704A, 1704B; i.e. a vertically split magnet shell. Since the magnet portions 1704A, 1704B overlap the joints 1715, the required tolerances with regard to the assembling of the shell parts can be lowered.

(47) In FIG. 3Q, the magnet assembly 1801 is similar to the embodiment illustrated in FIG. 3B. The shell parts 1805A, 1805B are of different shape, as the left shell part 1805A is a substantially flat element, whereas the right shell part 1805B is U-shaped. The left shell part 1805A may form part of the armature thereby providing the ability of a smaller receiver. Preferably the armature may be U-shaped.

(48) The end faces 1813, 1814 abut each other in a joint 1815 being perpendicular to the magnet portions 1804A, 1804B along the inner surface of the left shell part 1805A.

(49) FIG. 4 illustrates a further alternative of an embodiment of a magnet assembly 1901, in which the magnet shell comprises three shell parts 1905A, 1905B, 1905C. The upper shell part 1905A and the lower shell part 1905B being joined by an intermediate shell part 1905C.

(50) A magnet portion 1904A, 1904B is attached to each of the upper and lower shell part 1905A, 1905B.