Loudspeaker

<u>Technical field</u>

The invention is concerned with the training of speakers, especially with the formation of drive systems for such speakers as well as the mutual assignment of such speakers.

<u>State of the art</u>

According to the prior art it is known to drive systems of loudspeakers in such a way that a permanent magnet is connected to so-called yoke or yoke parts, wherein the yoke members, an annular gap is left, in which later the voice coil is connected to the speaker membrane is immersed. Such an arrangement, which comprises an axially magnetized to the longitudinal axis of the magnet system the permanent magnet is, for example, in<patcit id="pcit0001" dnum="DE4113017A"><text>DE-A-4113017</text></patcit> shown. Magnet systems with two permanent magnets show the writings<patcit id="pcit0002" dnum="DE4234069A"><text>DE-A-4234069</text></patcit> and <patcit id="pcit0003" dnum="DE4225156A"><text>DE-A-4225156</text></patcit>, Here with magnet systems are known which to the longitudinal axis of the magnet system having radially magnetized permanent magnets. These permanent magnets are either integrally formed or consist of a series of permanent magnet segments. Such arrangements are known from<patcit id="pcit0004" dnum="WO9303586A"><text>WO 93/03586</text></patcit> known. Also in these arrangements inference elements are present, which guide the magnetic flux provided by the permanent magnet, so that the annular gap sufficient induction is provided. A speaker with two radially magnetized permanent magnets, but without return elements is from the<patcit id="pcit0005" dnum="US4327257A"><text>US 4,327,257</text></patcit> known.

both the elaborate production and the high weight and large volume is perceived in these systems or loudspeakers as disadvantageous. The invention is therefore based on the problem to provide a magnet system which avoids the disadvantages of the prior art.

<u>Summary of the Invention</u>

This object is achieved by a speaker with the features of claim. 1 Advantageous embodiments and developments of the invention are the claims 2 -10 removed.

Basic idea of ​​the present invention is to use the output from a permanent magnet radialmagnetisierten leakage flux for driving a voice coil. This makes it possible to form the receiving parts for the permanent magnet made of a paramagnetic or diamagnetic material. This has the consequence that a considerable space and weight saving is achieved because the geometric requirements for the yoke parts, which must be considered by the prior art for conducting the magnetic flux in these parts, according to the invention are insignificant. The production of magnetic systems is greatly simplified, since steps which are necessary for connecting the usual inference parts according to the prior art, dispensed according to the invention. Rather, the receiving part according to the invention only forms the rear closure of the speaker or a supporting structure for the permanent magnet and the other components of the speaker.

Since a cone speaker usually has a loudspeaker frame, which is connected to the magnet system can be since the receiving part according to the invention has no function with respect to the magnetic flux and with regard to the use of the leakage flux also should not have, one-piece units from receiving part and loudspeaker frame manufactured very inexpensively.

Suitable materials for forming receiving parts or units of the receiving part and loudspeaker frame to plastics, metals and metal alloys offer. to use for the training of female parts in the aforementioned sense metal, since these materials the same time ensure good heat dissipation in the region of the drive system of the speaker is particularly advantageous.

A particularly effective use of the output from the permanent magnet flux leakage is provided when the magnet system is formed erfingdungsgemäß. In this case, the output from the permanent magnet flux leakage from both coils is used to drive a membrane.

In order to increase the pressure required to drive the membrane leakage flux, two or more permanent magnets axially spaced apart in the direction of the longitudinal axis of the magnetic system can be arranged. In such an arrangement each of these permanent magnets can be surrounded on its inner side and / or outer shell side of a voice coil. If additional voice coil for driving, for example, be used a membrane, it is necessary to rigidly connect these voice coil together. Also according to the invention the magnet system can be modified so that for example, all disposed on an inner lateral surface of the permanent magnet coil for driving a diaphragm and disposed on all of the other lateral surface coils are used to drive a different membrane.

Very particularly advantageous is the design of the loudspeaker is according to claim 9 or 10. If the respective voice coil bobbin formed as a tubular shape and the first end of the voice coil bobbin with a first membrane and the second end of this voice coil bobbin is connected to a second membrane and are the two membranes, their suspensions, etc. formed completely identical, such an arrangement can be used as a dipole antenna to produce, for example, a diffuse sound field for Dolby surround playback. Such diffuse sound fields according to the prior art formed by having two completely identical but inverse polarity reversal together speakers are used with separate volumes. With such arrangements but the desired effects are only possible when the two speakers have an identical up to 1- 2 dB playback frequency response. If these conditions are not complied with, the respective sound event is perceived as of from or as coming from behind. As appreciated, the identity can be ensured only through considerable effort in the production in the playback frequency response. However, if the arrangement for generating a diffuse sound field formed according to claim 9 or 10, be deviations, which are caused for example by production membrane differences or unavoidable manufacturing differences in assembling the speakers, compensated or averaged, the production-related deviations of all membranes, etc. by a mechanical coupling of the two membranes are effective in every operating state.

Summary of the figures

Show it:<ul><li><figref idrefs="f0001">figure 1</figref> a section through a known speaker;</li><li><figref idrefs="f0001">figure 2</figref> a perspective view of a permanent magnet;</li><li><figref idrefs="f0002">figure 3</figref> a development of the arrangement according to <figref idrefs="f0001">figure 1</figref>;</li><li><figref idrefs="f0003">figure 4</figref> another embodiment of the arrangement in accordance with <figref idrefs="f0001">figure 1</figref>;</li><li><figref idrefs="f0003">figure 5</figref> a section through a permanent magnet arrangement; and</li><li><figref idrefs="f0004">figure 6</figref> another embodiment of the arrangement in accordance with <figref idrefs="f0001">figure 1</figref>,</li></ul>

<u>Ways of carrying out the invention</u>

The invention will now be explained in more detail with reference to FIGS.

In <figref idrefs="f0001">figure 1</figref> is shown in section a noted speaker (10). This speaker (10) is substantially of a receiving part (11), a permanent magnet (12) and a membrane (13). In the present embodiment, the receiving portion (11) of a loudspeaker frame (11a) and a mandrel (11b) is formed. As the material of the parts (11a and 11b) of polycarbonate was used. A limitation to this material is not involved. Rather, in another - not illustrated example - other plastics, such as ABS, or metals, for example aluminum, are used as materials, provided that these materials have para- or diamagnetic properties. It is essential that at least the dome (11b), ie the part which directly with the permanent magnet (12) is in physical connection, is made of a paramagnetic or diamagnetic material, by the direct contact that from the permanent magnet (12) outgoing field not to weaken. Combinations are not excluded from the invention, which have a mandrel (11b) of a paramagnetic or diamagnetic material and a loudspeaker frame (11a) of a ferro-magnetic material.

As appreciated, but make combinations of the parts (11a, 11b) of paramagnetic or diamagnetic materials the most advantageous training. In addition to the neutral effect of such combinations in the stray field of the permanent magnet (12), such combinations are very inexpensive in the production , The latter applies in particular if the receiving part (11) is integrally formed. Such integral formation of a receiving part (11) is in<figref idrefs="f0003">figure 4</figref> shown.

The in <figref idrefs="f0001">figure 1</figref> Dom shown (11b) is circular, said the basket (11a) facing away from the end of the mandrel (11b) towards the basket (11a) near the end of a smaller diameter. This configuration of the dome (11b) is used for the positive reception of the annular shaped permanent magnet (12). Just for completeness it should be noted that the mandrel (11b) is not necessary that the inner diameter of the permanent magnet must (12) filled in completely or partially. A configuration in which the mandrel (11b) of the inner diameter of the permanent magnet (12) does not completely fill in<figref idrefs="f0003">figure 4</figref> shown.

In accordance <figref idrefs="f0001">figure 1</figref> shown basket (11a) has a conical membrane (13) is used. The upper end of the membrane (13) is connected by means of a bead (14) to the basket (11a). The lower end of the membrane (13) includes a voice coil support (15) which projects into the coated by the membrane (13) space. To the outer surface of the voice coil support (15) the Sehwingspule (16) is wound. Although this arrangement of the voice coil (16) on the outer surface of the voice coil bobbin (15) from a manufacturing standpoint it is advantageous, it can make better use of the leakage flux can be necessary to place the voice coil (16) on the inner casing of the voice coil bobbin (16) (the latter is in<figref idrefs="f0001">Fig. 1</figref> Not shown).

Feiner is a centering diaphragm (17) is provided, which with the basket (11a) and the diaphragm (13) is connected and which maintains the voice coil (16) centrally to the longitudinal axis of the magnet system or the speaker (10).

In addition, the mandrel (11b), the permanent magnet (12) and the voice coil (16) by means of a dust cap (18) can be covered. This dust cap (18) has to protect conventional speakers (10) on the object, the narrow annular gap before particle accumulations. This object also has the dust cap (18) used in the system according to the invention, although the distances between the voice coil (16) and the permanent magnet (12) are not so critical in the inventive systems which utilize the leakage flux, so that when the dust protection does not exist, the accumulating particles are of subordinate importance.

As already indicated several times, the drive of the current flowing through voice coil (16) is carried out in the stray field which is produced by a radialmagnetisierten permanent magnet (12). Therefore, in the exemplary embodiment in accordance with<figref idrefs="f0001">Fig. 1</figref> the North pole (N) on the outer lateral surface (19) and the south pole (S) on the inner lateral surface (20) of the permanent magnet (12).

As appreciated, the induction of radialmagnetisierten permanent magnet (12) along the lateral surfaces 19/20 is constant, so that the voice coil (16) over its entire displacement path moves in a uniform magnetic field, which ultimately leads to a very linear operation of the loudspeaker ( 10).

The formation of permanent magnets (12) is not limited to the one-piece circular ring shape. With<figref idrefs="f0001">FIG. 2</figref> is a permanent magnet (12) is shown which is octagonal formed and consists of a succession of permanent magnet segments (12a-h). Each of these segments (12a-h) is also magnetized radially as the segment (12a) indicated. The use of permanent magnets (12) in segments has the advantage that plate material can be used which can be easily magnetized opposite circular ring-shaped permanent magnet (12). In the<figref idrefs="f0001">FIG. 2</figref> Octagonal shape of the permanent magnet (12) shown is only exemplary.

In another - embodiment not shown - may be cuboid formed by the juxtaposition of only 4 segments of the permanent magnet (12).

In <figref idrefs="f0002">Fig. 3</figref> is a loudspeaker (10) demonstrated the derogation in accordance of the training <figref idrefs="f0001">Fig. 1</figref> two voice coil support (15 and 15 ') has. These two voice coil carrier (15, 15 ') are connected by a circular ring disc (21) with mutual spacing. In addition, each of the two voice coil support (15, 15 ') having a voice coil (16, 16') provided.

The mandrel (11b) facing away from the basket (11a) end with a disc (22), which is also made of a paramagnetic or diamagnetic material. The bottom (23) of the disc (22) is connected to a radialmagnetisierten Dauelmagneten (12) in a circular ring shape. The sake of completeness it should be noted that the disc (22) can also be formed from a ferro-magnetic material, although such a choice of material results in a slightly worse degree of efficiency.

Since the inner diameter of the annular permanent magnet (12) is larger than the outer diameter of the mandrel (11b), and both parts are constructed coaxially to each other, an "air gap" (24) is formed. In these "air gap" (24) of the coil (16) immersed connected voice coil support (15), while at the voice coil support (15 ') disposed voice coil (16') the outer lateral surface (19) of the permanent magnet (12) at a distance edged.

Since the two coils 'have the same winding direction, and thus the current flow direction in the two coils (16 16, (16, 16)' is the same), is in contrast to the embodiment according to <figref idrefs="f0001">Fig. 1</figref> accordance with the training <figref idrefs="f0002">Fig. 3</figref> the leakage flux considerably better utilized for driving the diaphragm (13). The latter conditions are also useful in coils (16, 16 ') with opposite winding sense erziehlbar when the two coils (16, 16') inverse to each other with a sound source (not shown) are reversed.

The sake of completeness it should be noted that, in in the preparation of, for example, <figref idrefs="f0001">Fig. 1</figref> and <figref idrefs="f0002">3</figref> shown speakers (10), the devices can be used without any major modifications, the mutandis for preparing arrays <patcit id="pcit0006" dnum="DE4113017A"><text>DE-A-4113017</text></patcit> be used. In particular, also in the arrangements according to the invention for aligning and securing the diaphragm (13) in the basket (11a) is usually used centering sleeves, which for the manufacture of speakers (10) between the pole core {mandrel (11b) and permanent magnet (12)} and the be voice coil support (15) are used, is used.

The training according <figref idrefs="f0002">Fig. 3</figref> with the two voice coils (16, 16 ') but is not limited to the driving of only one membrane (13). Rather, the stray flux of the radialmagnetisierten permanent magnet (12) can also be used to drive different membranes (13, 13 ') can be used. Such ratios are in<figref idrefs="f0003">Fig. 4</figref> shown. Here, rather than their representation in accordance with the<figref idrefs="f0001">Fig. 1</figref> the permanent magnet ring (12) on the mandrel (11b) is placed. Between the inner circumferential surface (20) of the radially magnetized permanent magnet ring (12) and the mandrel (11b) there is an "air gap" (24), in which a voice coil bobbin (15 ') provided with a voice coil (16') is wound is immersed. The upper end of the voice coil support (15 ') is provided with a dome-shaped diaphragm (13'). The outer edge of the dome-shaped membrane (13 ') is connected to the upper end of the permanent magnet (12).

If this voice coil (16 ') (supplied with an audio signal of a sound source, so the membrane 13)' may be used, for example, to emit high-frequency sound signals, while the membrane (13) is used for radiating medium-frequency sound signals, for example. To phasality by the two membranes (13, 13 ') (to achieve radiated Teiltonfrequenzen, both voice coils 16, 16) should' be reversed in this embodiment, inversely related to the sound source, when both coils (16, 16 '), for example, for manufacturing reasons have the same winding sense.

<figref idrefs="f0003">Fig. 5</figref> shows a comparison of <figref idrefs="f0001">Fig. 1</figref> modified Dorn-permanent magnet combination. Here, two permanent magnets (12, 12 ') at a mutual axial distance on the mandrel (11b) is provided. Each of these permanent magnets (12, 12 ') is radially magnetized, with like poles of the two permanent magnets (12, 12') point in the same direction. The express shell surfaces (19) of the two permanent magnets (12, 12 ') is a voice coil support (16) arranged next to which is also at a mutual axial distance two voice coils (16,16' are fixed).

Such an arrangement should be selected when the leakage flux only a permanent magnet (12) alone is sufficient not to drive a membrane (13). If the two coils (16, 16 ') for driving only be used a membrane (13), the current flow direction must in both voice coils (16, 16') have the same direction.

By the voice coil support (15) intersecting double-dotted dashed lines indicated that in <figref idrefs="f0003">Fig. 5</figref> can be used arrangement shown also for driving various membranes (13), when the two oscillation coils (16, 16 ') are not arranged on a common voice coil support (15) but independent voice coil support (15' ') have.

It is also not necessary that the mandrel (11b) ACCORDANCE <figref idrefs="f0003">Fig. 5</figref> completely the inner diameter of the two permanent magnets (12, 12 ') fills. Rather, in can<figref idrefs="f0003">Fig. 5</figref> Dorn shown (11b) and in accordance with the in <figref idrefs="f0002">Fig. 3</figref> and <figref idrefs="f0003">4</figref> embodiments shown modified to be formed.

For completeness' sake it is noted that one in connection with the <figref idrefs="f0001">figures 1</figref> and <figref idrefs="f0003">5</figref> Dorn-permanent-magnet combination shown very advantageous manner can be formed, that the or each permanent magnet (12, 12 ') are inserted into an injection mold, so that the connection of the permanent magnets (12, 12') simultaneously with the forming of the mandrel (11b can be carried out) or from mandrel (11b) and basket (11a) existing recording (11).

In <figref idrefs="f0004">Fig. 6</figref> is a dipole antenna (10 ') shown the right and left of the double-dotted broken line one speaker (10' showing '). Each of these speakers (10 '') corresponds essentially to a in <patcit id="pcit0007" dnum="DE4113017A"><text>DE-A-4113017</text></patcit> (<figref idrefs="f0001">Fig. 1</figref>) Shown speaker. Notwithstanding this, however, is in<figref idrefs="f0004">Fig. 6</figref> the magnet system formed. This is characterized in that it is formed by a radially magnetized permanent magnet (12). Since the first end (25) of the voice coil bobbin (15) with a membrane (13) and the second end (25 ') of the voice coil carrier (15) is provided with another membrane (13'). Is now connected to the voice coil support (15) connected to the voice coil (16) supplied with an audio signal, the voice coil (16) and with it via the voice coil support (15) moves each of the two membranes (13, 13 ') in direction of the arrow. This means that an air compression takes place at the membrane (13 '), while an air dilution is due to the diaphragm (13). Since, however, both membranes (13, 13 ') resistors are coupled via the common voice coil support (15), to act for example on the membrane (13') present and the free stroke of said membrane (13 ') affecting also to the stroke of the membrane from (13), so that they will receive a the membrane (13 ') identical stroke behavior. This meant that both diaphragms (13,13 ') proposed identical reproduction frequencies, which is to generate a diffuse sound field is of considerable importance.

Finally, it should be noted that in another - according to the embodiment in an arrangement - not shown <figref idrefs="f0004">Fig. 6</figref> also in <figref idrefs="f0003">Fig. 5</figref> shown permanent magnet rings (12, 12 ') can be used. An arrangement, according to<figref idrefs="f0004">Fig. 6</figref> be modified so that, according to <figref idrefs="f0003">Fig. 4</figref> both in <figref idrefs="f0004">Fig. 6</figref> shown membranes (13, 13 ') of two respectively with lateral distance from the inner and outer circumferential surface (19, 20) of the permanent magnet (12) arranged in the voice coil (16, 16') are driven.