Nokia Technology Gmbh

Harman Audio Electronic Systems Gmbh

Manfred Aigner

Stefan Geisenberger

Gerhard Krump

Voice coil assemblies are designed so that the solder points which connect the coil wires and the stranded wires, are connected via a separate adhesive seam to the diaphragm or the voice coil carrier. According to the invention, the solder points are placed in the adhesive seam by which the centering membrane is connected to the voice coil carrier. The first region of the centering membrane is designed to be open in the direction of the voice coil. By locating the solder points in the adhesive seam a voice coil assembly is created which is distinguished by a low design height, a good current-carrying capacity and an excellent height reproduction.

Voice coil assembly

According to the state of the art, insofar as the respective components of the loudspeaker cannot be built in one piece, the respective components of the loudspeaker are joined to each other by adhesives. For example, it is known to bond the aluminum voice coil support (10) to the paper loudspeaker diaphragm (11). However, if loudspeakers with such bonded joints must operate above 120 degrees Celsius, no long-term continuous operation of the mechanically highly stressed adhesion can be expected. The invention therefore has the task of presenting a very strong mechanical joint of the loudspeaker components. The task is fulfilled according to the invention, in that at least the surface areas (13.1, 13.2) of the loudspeaker components to be joined to each other �perhaps the voice coil support (10) and the loudspeaker diaphragm (11)! are made of metals that can be ultrasonically welded to each other, and that the joint between the two components of the loudspeaker is ultrasonically weldable. Insofar as required, an insulation arrangement (16) can be placed between the two just mentioned loudspeaker components, which can be ultrasonically welded to the respective components of the loudspeaker �in this instance loudspeaker diaphragm (11) and voice coil support (10)!, through their metal coatings (19.1, 19.2), which are also made of ultrasonically weldable metal.

Loudspeakers

In the state of the art, most loudspeaker diaphragms 10 and the voice coil supports 11 are joined by adhesives. However, even high-grade adhesives fail if such loudspeakers are subjected to continuous operating temperatures much above 120 degrees Celsius. The one-piece construction of loudspeaker diaphragm 10 and voice coil support 11 is also limited. It is particularly difficult to produce one-piece metal constructions by means of the deep-draw process. It is therefore the task of the invention to present a joint of loudspeaker diaphragm 10 and voice coil support 11, which is simple to produce, can be subjected to high temperatures and is free of adhesives. This task is fulfilled in that the upper rim 19 of the voice coil support 11 is flared together with the upper rim 16 of a neck 12 formed on the diaphragm 10. In addition the invention proposes to join the neck 12 of loudspeaker diaphragm 10 to the voice coil support 11 through the effect of a ring-shaped part 23. If the neck 12 of diaphragm 10 is located between the ring-shaped part 23 and the voice coil support 11, the latter has the function of opposing the pressure (force) exerted by the ring-shaped part 23 on the outside jacket of the neck 12.

Loudspeaker suitable for high-temperature use having a non-adhesive

According to the state of the art, high-temperature resistant centering of loudspeakers is configured so that a rod (17) that is connected to the pole body (14) serves as a guide for a bushing (19) connected to the voice coil support (11). However, the narrow space between the rod (17) and the bushing (19) leads to friction between the rod (17) and the bushing (19) during excursion movements of the voice coil support (11), which retards the free movement of the voice coil support (11). The invention therefore has the task of providing high-temperature resistant centering for loudspeakers, in which any touching of rod (17) and bushing (19) is eliminated. The invention makes the rod (17) and the bushing (19) from magnetic material, and magnetizes this material radially to the loudspeaker axis (16). If the facing magnetic areas of rod (17) and bushing (19) have the same polarity, no-contact centering of the bushing (19) over the rod (17) is achieved by the mutual rejection.

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Schwarzach, Germany

Manfred Aigner