Patent ID: 12250531

DETAILED DESCRIPTION

In the following, embodiments of the invention will be described in detail with reference to the accompanying drawings. It is to be understood that the following description of embodiments is not to be taken in a limiting sense. The scope of the invention is not intended to be limited by the embodiments described hereinafter or by the drawings, which are taken to be illustrative only.

The drawings are to be regarded as being schematic representations and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling.

Some examples of the present disclosure generally provide for a plurality of mechanical and electrical components. All references to the components and the functionality provided by each are not intended to be limited to encompassing only what is illustrated and described herein. While particular labels may be assigned to the various components disclosed, such labels are not intended to limit the scope of operation for the components. Such components may be combined with each other and/or separated in any manner based on the particular type of implementation that is desired.

FIG.1shows a sectional view of a loudspeaker100. The sectional view is taken along a longitudinal axis101of the loudspeaker100. Several of the below described components may have an axis of rotational symmetry, for example, cylindrical or tubular components, and the axis of rotational symmetry of such a component may be aligned to the longitudinal axis101.

The loudspeaker100comprises a magnet assembly110, a first diaphragm120, a second diaphragm130, and a basket140. The magnet assembly110, the first diaphragm120, the second diaphragm130, and at least parts of the basket140may each have a rotationally symmetrical shape with an axis of rotational symmetry aligned to the longitudinal axis101.

The first diaphragm120is arranged spaced apart from the second diaphragm130. The first diaphragm120has a dome shape with an apex of the dome shape directing in an upward direction along the longitudinal axis101inFIG.1. The second diaphragm130has a dome shape with an apex of the dome shape directing in a downward direction along the longitudinal axis101inFIG.1. The first and second diaphragms120,130may have essentially the same shape which may be rotationally symmetric with respect to the longitudinal axis101. The basket140is provided between the first diaphragm120and the second diaphragm130. The first diaphragm120may be coupled to the basket140via a surround122, and the second diaphragm130may be coupled to the basket140via a surround132. The surrounds122and132may be made of an elastic material, for example a rubber or plastics. The surrounds122and132enable a back-and-forth movement of the diaphragms120and130, respectively, in the direction of the longitudinal axis101.

The above-described shape of the first and second diaphragms120,130is an example and the first and second diaphragms120,130may have any other shape, for example a conical shape, a flat disk shape, a spherical shape, a dome shape, a horn shape, a funnel shape or a combination thereof. Each of the first and second diaphragms120,130may be made from one piece or assembled from several pieces, which are made of the same or different materials.

For example, the basket140in combination with the first and second diaphragms120,130and the surrounds122,132may form a closed enclosure such that the volume inside the loudspeaker100is essentially decoupled from a surrounding. In other examples, the volume inside the loudspeaker100may be coupled with surrounding volume, for example via openings in the basket140.

The magnet assembly110is mounted within the basket140. The magnet assembly110comprises a magnet111, a magnetic piece112and a spacer113. The magnet111, the magnetic piece112and the spacer113may each have a rotationally symmetrical shape with an axis of rotational symmetry aligned to the longitudinal axis101.

The spacer113is made of non-magnetic material, for example, a paramagnetic, diamagnetic, or antiferromagnetic material. For example, the spacer113may be made of plastics or a non-magnetic metal like aluminum.

The magnet111may comprise a permanent magnet comprising ferromagnetic materials, for example iron, nickel, cobalt and/or neodymium. Additionally, the magnet111may be provided at each end in the direction of longitudinal axis101with a corresponding pole piece, i.e., a first pole piece114at an upper end inFIG.1and a second pole piece115at a lower end inFIG.1. The magnet111may be a hollow cylindrical magnet, a so-called ring magnet with a first magnetic polarity at the upper end inFIG.1, for example a north pole N, and a second magnetic polarity at the lower end inFIG.1, for example a south pole S. The first and second pole pieces114,115may each have a washer shape with an axis of rotational symmetry aligned to the longitudinal axis101. The first and second pole pieces114and115may be made of a ferromagnetic material, for example iron, nickel or cobalt such that they guide the magnetic field from the magnet111and may be considered to extend the poles of the magnet111. Therefore, when the pole pieces114and115are present, in the following, the combination of magnet111and pole pieces114,115will be referred to as magnet111also.

The magnetic piece112may be made of ferromagnetic material, for example iron, nickel or cobalt, and may have a hollow cylindrical shape with an axis of rotational symmetry aligned to the longitudinal axis101. As shown inFIG.1, an outer diameter of the magnetic piece112may be smaller than an inner diameter of the magnet111. The spacer113couples the magnet111with the magnetic piece112such that at least at the upper and lower ends of the magnet111(including the pole pieces114,115) a gap150exists between the magnet111and the magnetic piece112. The gap150may have a width in the radial direction of a few millimeters, for example in a range of 1 to 5 millimeters. The non-magnetic spacer may be arranged at a center of the gap150in a direction of the longitudinal axis101. The spacer113defines the width of the gap150and assures a fixed arrangement of the magnet111with respect to the magnetic piece112. A length of the magnet111and the magnetic piece112in the direction of the longitudinal axis101may be essentially the same and defines a length of the gap150in the direction of the longitudinal axis101. The length of the gap150may be in the range of a few millimeters to a few centimeters, for example in a range of 10 to 50 millimeters. It is to be noticed that the gap150may be partly filled with the spacer113. However, in particular the end sections of the gap150, i.e., the upper end and the lower end in the direction of the longitudinal axis101, may not be occupied by the spacer113.

Due to the ferromagnetic properties of the magnetic piece112, a magnetic field generated by the magnet111is guided in radial direction through the gap150and the magnetic piece112. In detail, a magnetic field170(for example B-field) may propagate from the north pole N at the upper end of the magnet111(if present, via the first pole piece114) in a radial direction to the upper end of the magnetic piece114which guides the magnetic field170in the downward direction within the magnetic piece114to the lower end of the magnetic piece114, where it propagates in a radial direction to the south pole S at the lower end of the magnet111(if present, via the second pole piece115).

Near an outer circumference of the first diaphragm120a first voice coil121is provided which extends into the gap150at the upper end of the magnet assembly110. The first voice coil121comprises a tubular carrier123on which a plurality of coil windings124are arranged. The carrier123may be made of a non-magnetic material, for example paper, aluminum or plastics, like polyimide, for example, Kapton. An inner diameter of the carrier123is larger than an outer diameter of the magnetic piece112. An outer diameter of the coil windings124is smaller than an inner diameter of the magnet111. The voice coil121is movable in the direction of the longitudinal axis101in the up and down directions inFIG.1.

Likewise, near an outer circumference of the second diaphragm130, a second voice coil131is provided which extends into the gap150at the lower end of the magnet assembly110. The second voice coil131comprises a tubular carrier133on which a plurality of coil windings134are arranged. The carrier133may be made of non-magnetic material. An inner diameter of the carrier133is larger than an outer diameter of the magnetic piece112. An outer diameter of the coil windings134is smaller than an inner diameter of the magnet111. The voice coil131is movable in the direction of the longitudinal axis101in the up and down directions inFIG.1.

As a result, the first and second diaphragms120and130can be deflected independently by energizing the first and second voice coils124and134. However, only a single magnet assembly110is needed which provides a gap150with magnetic fields in which both voice coils124and134may be operated.

For example, in operation of the loudspeaker100, the diaphragms120,130may be controlled such that they are moving in opposite directions. However, this is only an example and the diaphragms120,130may be controlled independent from each other such that a movement of the first diaphragm120is controlled independent from the movement of the second diaphragm130.

As further shown inFIG.1, an elastic element160may be provided between the first diaphragm120and the second diaphragm130. A first end of the elastic element160is coupled to a center, for example the apex, of the first diaphragm120. A second end of the elastic element160is coupled to a center, for example the apex, of the second diaphragm130. Optionally, a first fixation pad161may be arranged between the first end of the elastic element160and the first diaphragm120, and a second fixation pad162may be arranged between the second end of the elastic element160and the second diaphragm130. As shown inFIG.1, the elastic element160may comprise a spring element, made for example of metal or plastics. Although not shown, the elastic element160may comprise a plurality of springs or may comprise a cylindrical or bellows-shaped hollow element of elastic material, for example rubber or foam.

As described above, some of the components of the loudspeaker100may have a rotational symmetry with respect to longitudinal axis101. Therefore, components on the right-hand side inFIG.1are shown in symmetry to components on the left-hand side ofFIG.1. For further clarification,FIG.2shows a sectional view along sectional plane A-A andFIGS.3and4show sectional views of various examples along sectional plane B-B.

FIG.2shows a sectional view along sectional plane A-A ofFIG.1. The sectional plane A-A extends perpendicular to the longitudinal axis101. As shown, the basket140encloses the washer-shaped upper pole piece114. Although, the basket140in the illustrated example completely encloses the pole piece114, this is only an example, and the basket may have cutouts or may comprise of a plurality of parts coupled to the pole pieces114,115and the magnet111, for example by gluing or press fitting. Furthermore, the basket140may comprise support structures, for example connecting straps, for mounting the loudspeaker100at an installation space, for example in a door, dashboard, ceiling, seat or headrest of a vehicle. The upper pole piece114has an inner opening in which the magnetic piece112is arranged with a gap150between an inner circumference of the upper pole piece114and an out circumference of the magnetic piece112. The first voice coil121comprising the carrier123and the coil windings124is at least partly arranged in the gap150. A gap between an outer circumference of the coil windings124and an inner circumference of the pole piece114is provided such that the voice coil121does not contact the pole piece114when moving up and down along the direction of the longitudinal axis101. Within the inner circumference of the voice coil121, the magnetic piece112is arranged spaced apart from the inner circumference of the voice coil121such that the voice coil121does not contact the magnetic piece112when moving up and down along the direction of the longitudinal axis101. The magnetic piece112may have a hollow cylindrical shape such that the cross section is a ring as shown inFIG.2.

FIG.3shows a sectional view along sectional plane B-B ofFIG.1. The sectional plane B-B extends perpendicular to the longitudinal axis101essentially in the center of the length of the magnet assembly110. In particular, plane B-B extends through the spacer113. As shown inFIG.3and described above in connection withFIG.2, the basket140encloses the washer-shaped pole pieces114,115and the magnet111. The magnet111may be glued or press fitted to the basket140. The magnet111is a ring magnet, i.e., the magnet111has hollow cylindrical shape. At an inner circumferential surface of the magnet111the spacer113is mounted, for example, by gluing or press fitting. At an inner circumference surface of the spacer113, the magnetic piece112is mounted, for example, by gluing or press fitting. It is to be noticed, that inFIGS.2and3the elastic element160is not shown for reasons of clarity.

FIG.4shows a sectional view along sectional plane B-B ofFIG.1of another example of implementing the spacer113. In the example ofFIG.4, the spacer113has cutouts thus forming an inner ring113a,an out ring113band a plurality of spokes-like elements113c.The inner ring113ais in contact with the magnetic piece112. The outer ring is in contact with the magnet111or the pole pieces114,115. The spoke-like elements113cconnect the inner ring113aand the outer ring113b.In the example shown inFIG.4, the inner ring113ais connected via twelve spoke-like elements113cto the outer ring113b.However, this is an example only, and the spacer113may have any other structure which allows a fixed arrangement of the magnetic piece112with respect to the magnet111and/or the pole pieces114,115.

FIG.5shows a further loudspeaker100. Compared to the loudspeaker100shown inFIG.1, in the loudspeaker100ofFIG.5the magnet assembly110is modified such that the magnet111is arranged inside the magnetic piece112. However, the functionality of the loudspeaker100ofFIG.5is essentially the same as the functionality of the loudspeaker100ofFIG.1. The magnetic fields in the gap150for the first and second voice coils121and131are generated by a single magnet assembly110, for example, a single ring magnet111in connection with the magnetic piece112. The spacer113keeps the magnet111in position with respect to the magnetic piece112.

FIG.6illustrates a loudspeaker100which essentially corresponds to the loudspeaker100ofFIG.1. In contrast toFIG.1, the optional first and second fixation pads161and162are not present in the loudspeaker100ofFIG.6. Instead, the first end of the elastic element160is directly coupled to the center, for example, the apex, of the first diaphragm120, and the second end of the elastic element160is directly coupled to the center, for example, the apex, of the second diaphragm130, for example by gluing.

FIG.7illustrates a further loudspeaker100. Compared to the loudspeaker100shown inFIG.1, the loudspeaker100ofFIG.7comprises a support element164arranged within the magnetic piece112at a central position with respect to the longitudinal axis101. For example, the support element164may have a disk shape. An outer diameter of the support element164may be essentially the same as an inner diameter of the magnetic piece112. In other examples, the support element164may have a bar shape extending along an inner diameter of the magnetic piece112. The support element164may be fixed within the magnetic piece112by press fitting or gluing.

Instead of the elastic element160of loudspeaker100shown inFIG.1, the loudspeaker100ofFIG.7may be provided with a first elastic element160abetween the first diaphragm120and the support element164, and with a second elastic element160bbetween the second diaphragm130and the support element164. A first end of the first elastic element160ais coupled to a center, for example the apex, of the first diaphragm120. A second end of the first elastic element160ais coupled to one side of the support element164. A first end of the second elastic element160bis coupled to a center, for example the apex, of the second diaphragm130. A second end of the second elastic element160bis coupled to another side of the support element164. Optionally, a first fixation pad161may be arranged between the first end of the first elastic element160aand the first diaphragm120, and a second fixation pad162may be arranged between the first end of the second elastic element160band the second diaphragm130. As shown inFIG.7, the first and second elastic elements160a,160bmay each comprise a spring element, made for example of metal or plastics. Although not shown, the first and second elastic elements160a,160bmay each comprise a plurality of springs or may comprise a cylindrical or bellows-shaped hollow element of elastic material, for example rubber or foam. The use of the two separate elastic elements160a,160bmay utilize controlling the diaphragms120,130independent from each other, e.g., deflection of diaphragm120does not influence deflection of diaphragm130.

FIG.8illustrates a loudspeaker100. Like the loudspeaker100of FIG:7, the loudspeaker ofFIG.8comprises two elastic elements160cand160d.However, loudspeaker100ofFIG.8does not comprise the support element164. The loudspeaker100ofFIG.8comprises the first elastic element160cand the second elastic element160darranged along the longitudinal axis101and at least partially within the magnetic piece112. A first end of the first elastic element160cis coupled to a center, for example, the apex, of the first diaphragm120. A second end of the first elastic element160ais coupled to the magnetic piece112. For example, the first elastic element160cmay comprise a spring. A spring wire at the second end of the first elastic element160cmay be formed as shown inFIG.8to contact the magnetic piece112, for example at an upper base of the magnetic piece112. A first end of the second elastic element160dis coupled to a center, for example the apex, of the second diaphragm130. A second end of the second elastic element160dis coupled to the magnetic piece112. For example, the second elastic element160dmay comprise a spring. A spring wire at the second end of the second elastic element160dmay be formed as shown inFIG.8to contact the magnetic piece112, for example at a lower base of the magnetic piece112. The spring wires may be fixed to the magnetic piece112by gluing, welding or soldering.

In general, the elastic elements may provide guidance in the direction of the longitudinal axis101. For example, the elastic elements may inhibit or reduce a deflection of the corresponding diaphragm120,130in the lateral direction, i.e., in a radial direction perpendicular to the longitudinal axis101. The elastic elements enable deflection in the direction of the longitudinal axis101and provide a restoring force to the rest position for the corresponding diaphragm120,130.

FIG.9shows a further loudspeaker100with a magnet assembly110in which the magnet111is arranged inside the magnetic piece112. The functionality of the loudspeaker100ofFIG.9is essentially the same as the functionality of the loudspeaker100ofFIG.1. The magnetic fields in the gap150for the first and second voice coils121and131are generated by a single magnet assembly110, for example, a single disk magnet111in connection with disk shaped pole pieces114,115and the magnetic piece112. The spacer113keeps the magnet111in position with respect to the magnetic piece112. A washer shaped support ring167is provided between the basket140and the magnetic piece112to keep the magnetic piece112in position with respect to the basket140. Elastic elements160i,160j,160kand160mare provided between the support ring167and the first and second diaphragms120,130. For example, elastic element160imay be coupled between an upper side of the support ring167and the first diaphragm120. At a diametric opposite position, the elastic element160kmay be coupled between the upper side of the support ring167and the first diaphragm120. Likewise, elastic element160jmay be coupled between a lower side of the support ring167and the second diaphragm130, and, at a diametric opposite position, the elastic element160mmay be coupled between the lower side of the support ring167and the second diaphragm130. More than two elastic elements may be provided at each side of the support ring167, for example three, four, six, eight or any other number. The elastic elements may be provided within an annular space delimited by the magnetic piece112and the basket140. At each side of the support ring167, the elastic elements160may be arranged at a uniform distance from each other in the circumferential direction, i.e. evenly distributed in the circumferential direction.

In other examples, only one elastic element may be provided at each side of the support ring167, or one elastic element may be provided extending from the first diaphragm120to the second diaphragm130. The elastic element may comprise for example a spring with an inner diameter larger than an outer diameter of the magnetic piece112, or the elastic element may comprise for example a tubular element or a bellows-shaped hollow element made of rubber or foam with an inner diameter larger than an outer diameter of the magnetic piece112. The elastic element may surround the magnetic piece112in a circumferential direction of the magnetic piece112. The elastic element may be arranged within the annular space between the magnetic piece112and the basket140and may contact the first and/or second diaphragms120,130near an outer edge of the first and second diaphragms120,130, respectively. An axis of rotational symmetry of the elastic element may be aligned to the longitudinal axis101.

FIG.10shows a further loudspeaker100with a disk-shaped magnet111in connection with first and second disk shaped pole pieces114,115as loudspeaker100shown inFIG.9. The loudspeaker100ofFIG.10comprises a first elastic element160nbetween the first diaphragm120and the first pole piece114and a second elastic element160pbetween the second diaphragm130and to the second pole piece115. A first end of the first elastic element160nis coupled to the first diaphragm120. A second end of the first elastic element160nis coupled to the first pole piece114. A first end of the second elastic element160pis coupled to the second diaphragm130. A second end of the second elastic element160pis coupled to the second pole piece115. Optionally, a first fixation pad may be arranged between the first end of the first elastic element160nand the first diaphragm120, and a second fixation pad may be arranged between the first end of the second elastic element160pand the second diaphragm130. As shown inFIG.10, the first and second elastic elements160n,160pmay each comprise a spring element, made for example of metal or plastics. Although not shown, the first and second elastic elements160n,160pmay each comprise a plurality of springs or may comprise a cylindrical or bellows-shaped hollow element of elastic material, for example rubber or foam. The use of the two separate elastic elements160n,160pmay utilize controlling the diaphragms120,130independent from each other, e.g., deflection of diaphragm120does not influence deflection of diaphragm130.