DE3518897A1 - Electrical sound generator - Google Patents

Abstract

The present invention relates to an electrical sound generator (1) with a vibration generator (piezoelectric element 3) and with an electronic exciter circuit (16) which form a constructional unit and are installed in a housing (6) preferably constructed as resonant element. In this arrangement, at least the connecting legs (13) and a ladder structure (14) which carries the electronic components (15) and electrically connects them to one another, and possibly also the diaphragm (5) are produced of one piece as coherent part, for example as stamped part of a strip of copper alloy. <IMAGE>

Description

Electric sounder

The present invention relates to an electric sounder according to the preamble of claim 1.

Such sounders are known.

For example, DE-OS 24 59 135 is a contactless buzzer with a resonator membrane can be removed, which by mechanical action by means of an excitation circuit controlled vibrator is excited to emit acoustic signals. That buzzer is together with the excitation circuit consisting of discrete electronic components built into a common housing. The excitation circuit is in the form of a printed circuit built on a carrier plate, which is inside the housing is permanently mounted and electrically connected to the connections of the vibrator. One such an arrangement must be constructed with a high degree of accuracy for precise operation will. Due to the large number of components required that are built into the housing are, or complete the housing, the assembly is relatively complex.

DE-AS 28 02 713 shows a contactless buzzer with a very similar structure as in DE-OS 24 59 135, but with the excitation circuit consist of a monolithically integrated bipolar circuit module should, which is attached to an integrally formed flange on the vibrator is. The circuit module has several connection lugs, which are connected via supply lines or are connected directly to connections of the vibrator.

The integrated circuit module required for this solution facilitates compared to the solution according to DE-OS 24 59 135, the assembly is slightly but - especially with regard to the simplicity of the necessary excitation circuit - relatively expensive to manufacture.

Furthermore, DE-OS 34 14 722 proposes a piezoelectric buzzer before, which consists of a thin, elastic carrier plate with a mounted on it piezoelectric element.

The piezoelectric element is electrical on both sides conductive thin-film electrodes provided, which on the facing away from the carrier plate Side of the piezoelectric element partially in the form of a conductor pattern, similar a printed circuit are formed. On this ladder pattern are the (discrete) electronic components of the excitation circuit soldered directly in such a way that that the electronic components are located at the vibration nodes. This solution simplifies the assembly of such a buzzer considerably, but lowers it however, the efficiency of the buzzer because of the damping of the vibrating parts due to the electronic components attached to it.

The object of the present invention is now to reduce the assembly effort to lower such a sounder further, the sounder as high as possible Maintain efficiency.

A sounder according to the preamble is used to solve this problem of claim 1 configured according to the characterizing features.

You can use the conductor structure to build the excitation circuit both conventional discrete components and chip components can be used. The formation of the electrical connections as connecting legs is a direct one The sounder can be built on printed circuit boards.

With such a sound generator constructed according to the invention can as Vibration generator any system, e.g. electromagnetic or piezoelectric powered systems are used.

Further advantageous refinements emerge from the subclaims.

So the conductor structure or the support structure and possibly also the connecting legs have auxiliary parts which have a mechanically stabilizing effect and make it easier to equip with components, etc. After assembly you can these auxiliary parts are at least partially removed. In addition, the auxiliary parts also be designed so that they are only removed after completion of the assembly Need to become. This can reduce the mechanical load on the components on the electrical Connection points are kept particularly small during assembly. Farther these auxiliary parts can also be designed in such a way that they facilitate the transport and facilitate positioning in automatic assembly systems.

In particular, the support structure can be used as a round membrane for an in advantageously usable piezoelectric element be formed, wherein then one of the electrical connections between the excitation circuit and the piezoelectric Element can be produced via this support structure.

The connecting legs with the conductor structure and possibly with the support structure and the auxiliary parts can be produced in the simplest way as stamped parts. The starting material for this can advantageously be made of elastic bands Copper-based material can be used, which is completely unproblematic in processing are.

In order to build the sound generator according to the invention on printed circuit boards To achieve a suitable cross-section of the connecting legs, these should preferably have an aspect ratio of 1: 4 to 1:16. By folding these connecting legs along its length you then get one for the round PCB holes very suitable cross-section.

Further advantages and advantageous configurations are shown in the drawing and can be taken from the following description of the invention.

The drawing shows in detail in FIG. 1 a preferred exemplary embodiment a sounder; FIG. 2 shows a cross section through a sound generator according to FIG. 1; FIG. 3 shows a plan view of a conductor structure from a sound generator according to FIG. 1 or 2; 4 shows a second plan view of a conductor structure with an additional one Support structure used as a membrane; Fig. 5 is a third plan view on a particularly advantageous conductor structure; 6 shows a further sound generator with the ladder structure according to Fiy. 5; 7 shows a cross section through the sound generator according to Fig. 6; 8 is a circuit diagram of an excitation circuit.

In Figures 1 and 2, a preferred embodiment is one electric sounder 1 in about five times natural size in a plan view (Fig. 1), or in cross section (Fig. 2) along the line drawn in Fig. 1 II-II shown.

A circular disk-shaped piezo element is used as the vibration generator 2 3 used with thin-film electrodes 4, which are attached to a round membrane 5, is preferably glued to this.

The membrane 5 consists, for example, of a thin, resilient metal sheet and is glued with its edge to a housing 6 made of a suitable plastic. The housing 6 is shown in Figure 1 with a breakout; shown which is the look releases into the interior of the housing 6 on the piezo element 3 and the membrane 5.

The housing 6 is constructed in a known manner, cylindrical, with a base area 8 of the cylinder is formed by the membrane 5.

The opposite top surface 9 has a centrally arranged Opening 10 for sound radiation. The housing 6 is preferably in the usual way designed as a Helmholtz resonator for the oscillation frequency to be emitted; it is in one piece together with an approximately cuboid support element 11, 11 'each formed on and below the top surface 9 next to the opening 10. The support element 11 has two or more channels 12 leading from the inside to the outside through which the connecting legs 13 of the sounder 1 are guided.

The connecting legs 12 are angled in the interior of the housing 6 and formed into a conductor structure 14 lying parallel to the piezo element 3, on which electronic components 15 of an excitation circuit 16 for controlling the piezo element 3 are attached. The control circuit 16 is flexible with the piezo element 3 Lines 17 connected. The flexible lines 17 are preferably direct onto the conductor structure 14 and onto the exposed thin-film electrodes 4 the front of the piezoelectric element 3 is soldered. The thin-film electrode bonded to the membrane 5 4 on the back of the piezo element 3 is electrically conductive due to the adhesive connected to the membrane 5, so that one of the flexible lines 17 directly on the Membrane 5 can be soldered.

Fig. 3 shows a plan view of the connecting legs 13 with the molded Conductor structure 14, as it is before installation in a sound generator 1 according to FIG. 1 or 2 is present.

In the case of the conductor structure 14 according to FIG. 3, which is preferably configured the two parallel connecting legs 13 are connected to one another by a transverse web 18. Three elongated conductor parts 19, 20, 21 are connected to these transverse webs 18 that run parallel to each other at a distance that is roughly their width and which extend in the opposite direction to the connecting legs 13.

One of the outer conductor parts 21 is significantly longer than that the other two conductor parts 19, 20 and at its free end are U-shaped in such a way that that the free leg 22 of the u forms a continuation of the central ladder part 20, but without touching it.

The connecting legs 13 with the molded conductor structure 14 are preferably from a thin, resilient sheet made of a suitable copper alloy manufactured using stamping technology.

The conductor structure 14 shown in Fig. 3 is already with the electronic Components 15 and the flexible lines 17 fitted, with chip components here are used. But it is also possible to use convergent components.

The conductor structure 14 according to FIG. 3 has auxiliary parts 23 which must be removed before installation in the housing 6. These auxiliary parts 23 are then necessary when the connecting legs 13 together with the conductor structure 14 as one-piece, coherent part, e.g. by punching, are to be produced. It is the cross strut of the U-shaped part on the ladder part 21, as well around the transverse web 18, which after equipping with components 15 along the dash-dotted line Lines 24 have to be removed e.g. by punching, as they are the exciter circuit 16 would short-circuit.

By removing the auxiliary parts 23 arise from the conductor structure 14 two parts that only have components 15 with the rest of the conductor structure 14 are connected, namely the central conductor part 20 and the free leg 22 of the U-shaped ladder extension. In addition, there are also the two connecting legs 13 are only connected to one another via the components 15.

This structure is now in connection with the piezo element 3 a functional excitation circuit 16 and has one for the other Assembly of the sound generator 1 has sufficient mechanical stability.

The further assembly is e.g. as follows: After the removal of the auxiliary parts 23 on the conductor structure 14, the connecting legs 13 inserted into the channels 12 of the support elements 11, 11 'on the housing 6 and there e.g. attached by ultrasonic welding. Then the conductor structure 14 is on the inside Support element 11 'bent over, and the flexible lines 17 are with the already Piezo element 3 glued to membrane 5 or soldered to membrane 5. The membrane 5 is then glued into the housing 6.

In the case of the sound generator according to the invention, there is accordingly a special one easy assembly with very few parts to assemble. In particular such sound generators can also be produced fully automatically.

Fig. 4 finally shows another to the. Connecting legs 13 integrally formed Conductor structure 14, but with an additional support structure 25 with the conductor structure 14 is connected. The support structure 25 serves as a membrane 5 for the piezo element 3 and is substantially circular.

The actual conductor structure 14 and the connecting legs 13 are For the most part constructed identically as in FIG. 3. The outer conductor parts 19 16 and 21, however, are elongated and merge into the circular support structure 25. In addition, the support structure 25 has a continuation of the central conductor part 20 a ladder part 26, which, however, does not touch the central side part 20. Instead, the U-shaped extension on the outer conductor part 21 is omitted.

In this embodiment too, auxiliary parts 23 are again provided, after the conductor structure 14 has been fitted with electronic components 15, as well as the support structure 25 with the piezo element 3 and the connection of the support structure 25 and piezo element 3 must be removed by means of the flexible lines 17.

It is (as in Fig. 3) to the transverse web 18 between the two connecting legs 13, as well as the two extended outer conductor parts 19 and 21 directly on the circular support structure 25. The to be removed Auxiliary parts 23 are marked by dot-dash lines 24.

The not removed conductor part 26 connects the now functional Excitation circuit 16 on the conductor structure 14 electrically and mechanically with the Support structure 25, which also serves as membrane 5. For the connection between Exciter circuit 16 and piezo element 3 are thus only two flexible lines 17 necessary, which further reduces the manufacturing costs.

The assembly of this exemplary embodiment takes place in the same way as in Fig. 3, the conductor part 26 being appropriately bent when the membrane 5 is glued in will.

In a further embodiment of the invention, it is also possible for the conductor structure 14 with the excitation circuit 16 according to FIG. 4 outside the Helmholtz resonator, e.g. to be mounted in or on an additional housing part on the casing of the housing 6.

Such an exemplary embodiment is illustrated with the aid of FIGS explained in more detail; the representations in these figures are about four times the natural Size on.

FIG. 5 shows a device that has not yet been equipped with electronic components 15 Conductor structure 14 seen from the component side, which is very similar to the Conductor structure 14 from FIG. 3 is constructed.

Only the outer conductor part 21 with its U-shaped design, and the free leg 22 of this U-shaped training are considerably longer than in Fig. 3. In addition, a connecting lug 27 is formed on the free leg 22, which protrudes obliquely outward in the direction of the other outer conductor part 19.

In addition, between the conductor structure 14, the conductor parts 19, 20, 21 are connected by the transverse web 18, and the connecting legs 13 an additional Fastening structure 28 arranged, which consists of two bulging outwardly struts 29 extending in the same direction as the connecting legs 13. The struts 29 or their bulges open into the transverse web 18 and extend beyond this up to the two outer ladder parts 19, 21. The struts 29 preferably each have one at the widest point of their bulge square cutout 30. The bulges themselves are asymmetrical with respect to the outbreaks 30 and have their greatest width near the beginning of the connecting legs 13 on.

The connecting legs 13 are formed by two additional transverse webs 31, 32 connected to one another, the transverse web 31 at the transition between the fastening structure 28 and the connecting legs 13 and the crosspiece 32 near the outer end of the connecting legs 13 is arranged.

The crossbars 18, 31, 32 and the cross strut of the U-shaped part on the conductor part 21 are auxiliary parts 23, which are drawn along the dash-dotted lines in FIG Separation line 24 at least partially during the production of the sound generator according to the invention and in particular removed after the assembly of the overall structure in or on the housing will.

Figure 6 shows a plan view of a sound generator 1 ', which with a conductor structure 14 according to FIG. 5 is constructed. Fig. 7 shows a cross section by the sound generator 1 'according to FIG. 6 along the section line shown there VII-VII.

The sounder 1 'consists of a cylindrical housing 6', on its lateral surface 33 a carrier 34 for the conductor structure 14 and on the opposite side of the lateral surface 33 two formations 35, which accordingly the outbreaks 30 are formed in the fastening structure 28, integrally formed. One The top surface 9 'of the housing 6' has a centrally arranged opening 10 'for sound radiation on. A base area 8 'of the cylindrical housing 6' is formed by a cup-shaped Membrane 5 'formed, which with its outer edge 36 on the wall of the housing 6 'attached, preferably glued. On the outward side of the "Bottom" of the cup-shaped membrane 5 'is a round piezoelectric element 3' with the usual Thin film electrodes 4 'attached. The side facing the membrane 5 ' arranged thin-film electrode 4 'is electrically conductively connected to the membrane 5', which in turn consists of a conductive material.

As in FIGS. 3 and 4, the conductors and Fastening structures 14, 28 with the connecting legs 13 are finished equipped Housing 6 'attached. For this purpose, the conductor structure 14 with the electronic components 15 equipped. Then part of the auxiliary part, preferably the transverse webs 18 and 31 and, if necessary, the transverse web 32 at the outer end of the connecting legs 13 removed.

As a result of being fitted with electronic components 15, they are self-supporting Conductor and attachment structures 14, 28 are used in this preferred embodiment additionally by the still existing U-shaped design on the ladder part 21 as well stabilized by the transverse webs 31 and 32 (on the connecting legs 13). Now will the fastening structure 28 above the cutouts 30 and perpendicular to the direction of extent the struts 29 bent at right angles in such a way that the components 15 ins Inner angles show. Preferably, the connecting legs 13 can also be bent out 37 received in order to acoustically decouple the sounder 1 'from its installation location. Furthermore, the terminal lug 27 on the free leg 22 of the outer conductor part bent in such a way that it is under slight tension after being attached to the sounder 1 ' rests on the outer edge 36 of the membrane 5 '. The one so bent and tipped Part of conductor structure 14, fastening structure 28 and connecting legs 13 is now to the housing 6 'constructed as follows: The conductor part 21 is together with the free leg 22 (in front of the cross strut of the U-shaped part) in brackets 38 inserted on the carrier 34. At the same time, the fastening structure 28 is with their outbreaks 30 pressed onto the projections 35 on the housing 6 '.

Thereafter, the projections 35 are hot caulked and the fastening structure 28 is together with the conductor structure 14 and the connecting legs 13 fixed to the Housing 6 'connected. When using projections 35 with a square cross-section in connection with square cutouts 30 in the fastening structure 28 a particularly great stability in the area of the conductor structure 14 in the event of manipulations reached in the area of the connecting legs 13.

Then the remaining auxiliary parts 23 (cross brace of the U-shaped Formation on the outer conductor part 21, as well as the transverse webs 31 and 32 at the outer end the connecting legs 13) removed. The necessary connections between the now functional excitation circuit 16 on the conductor structure 14 is on the one hand by the contact of the terminal lug 27 with the outer edge 35 of the membrane 5 ' Established, this connection is preferably made by an electrically conductive Glue point additionally fixed.

On the other hand, the exciter circuit 16 is not overdrawn - Litz wires with the thin-film electrodes 4 ', as in the case of the previously described ones Embodiments connected.

Of course, the conductor structure 14 can also be different than in the Figures 3, 4 and 5 can be configured: for example, three connecting legs 13 are provided, which are located on the corner points of a triangle, so as to be able to mount the sounder 1 in a mechanically stable manner on a circuit board (where possibly two connecting legs are electrically connected).

Furthermore, it is also possible for the connecting legs 13, the conductor structure 14 and possibly the support structure 26 together with an auxiliary frame, like him. is known, for example, in the case of integrated circuits. This will make the automatic Equipping considerably through simplified positioning by means of the subframe relieved.

As a starting material for the production of the connecting legs 13, the conductor structure 14 and possibly the support structure 26, for example, a 0.1 mm to 0.4 mm thick strip material is used made of a CuNiSn or CuSn6 alloy, from which the corresponding parts are made by means of a common method to be punched out. The width of the connecting legs 13 is preferably selected to be approximately equal to 1.6 mm, since the finished sound generator 1 the connecting legs to a width of about 0.8 mm, that is, to a normal dimension for the circuit board assembly, fold (squeeze). By the length the folding, the depth of insertion of the connecting legs 13 can be limited at the same time.

Finally, FIG. 8 shows a simple Scialtschela for one Excitation circuit 16 is shown. Other switching arrangements can of course also be used be used.

The circuit diagram of FIG. 8 has a transistor 40 and is provided for a piezo element 41 with three electrodes. There is a control electrode 42 connected to the base of transistor 40.

The other two electrodes 43, 44 are each connected to the collector, or the emitter of transistor 40 is connected. Furthermore is between the collector and base of transistor 40 is a bias resistor 45 and feedback capacitor 46 arranged in parallel.

The collector of transistor 40 is connected to one pole of the voltage supply + U connected, the emitter connected to the other via a current limiting resistor 47 Pole.

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Claims (11)

Claims 1. Electric sounder with a vibration generator, which with an excitation circuit made of electronic components electrically is connected and forms a structural unit with the same, with at least two after externally routed electrical connections and with one, if necessary, as a resonance element trained housing, characterized in that the electrical connections as Connection legs (13) formed and in the vicinity of the vibration generator (2) to one Conductor structure (14) are shaped that the electronic components (15) of the excitation circuit (16) are attached directly to the conductor structure (14), and that through the conductor structure (14) the electrical connection between the electronic components (15) is established is. 2. Electrical sounder according to claim 1, characterized in that that on the connecting legs (13) and / or on the conductor structure (14) a further support structure (25) is integrally formed. 3. Electrical sounder according to claim 2, characterized in that that on the support structure (25) the vibration-generating element (piezo element 3,3 ') of the sounder (1,1') is attached. 4. Electrical sounder according to one of claims 1 to 3, characterized characterized in that the connecting legs (13) and / or the conductor structure (14), or a fastening structure (28) is integrally formed on the carrier structure (25) is. 5. Electrical sounder according to claim 4, characterized in that that the fastening structure (28) has elements (cutouts 30) by means of which it can preferably be attached to the housing (6, 6 ') in a rotationally fixed manner. 6. Electrical sounder according to one of claims 1 to 5, characterized characterized in that the conductor structure (14) and optionally the support structure (25) and / or the fastening structure (28) and auxiliary parts stabilizing the connecting legs (13) (23), which at least partially after the application of the electronic Components (15) and, if applicable, the vibration-generating element (piezo element 3, 3 ') removed. 7. Electrical sounder according to claim 6, characterized in that that the remaining auxiliary parts (23) after the attachment or installation of the overall structure (connecting legs 13, fastening structure 28, conductor structure 14, support structure 29) on or into the Housing (6.6 ') must be removed. 8. Electrical sounder according to one of claims 1 to 6, characterized characterized in that the connecting legs (13) and the conductor structure (14), as well as possibly the support structure (25) and / or the fastening structure (28) made from a stamped part consist, which consists of a thin, electrically conductive and preferably resilient Material is made. 9. Electrical sounder according to claim 7, characterized in that that the stamped part is preferably made of a sheet metal part made of a suitable copper alloy consists. 10. Electrical sounder according to claim 7 or 8, characterized in that that the material of the connecting legs (13) at least on the sounder (1,1 ') remote end is folded. 11. Electrical sounder according to claim 9, characterized in that that the cross section of the connecting legs (13) in the unfolded state has an aspect ratio from 1: 4 to 1: 6.