SOUND ACTUATOR WITH ROBUST POSITIONING OF MAGNETIC POLE PLATE PACKETS

Abstract

An actuator, including an electric drive for converting electrical signals into mechanical forces and/or deflections, is disclosed. The drive having at least one coil through which the current of the electrical signal can flow and having at least two magnets which can electromagnetically interact with the coil. The actuator being designed to excite a body which can be connected to the actuator, in particular a flat body, to vibrate, as a result of which the body can emit acoustic sound. The two magnets each being assigned at least one pole plate, the first and the second magnet, each with the at least one associated pole plate, forming at least one first and one second magnetic pole plate packet and the actuator having a frame in which the two magnetic pole plate packets are arranged in a substantially form-fitting manner.

Claims

1. An actuator, comprising an electric drive for converting electrical signals into mechanical forces and/or deflections, the drive having at least one coil through which the current of the electrical signal can flow and having at least two magnets which can electromagnetically interact with the coil, the actuator being designed to excite a body which can be connected to the actuator to vibrate, as a result of which the body can emit acoustic sound, wherein the two magnets are each assigned at least one pole plate, the first and the second magnet, each with the at least one associated pole plate, forming at least one first and one second magnetic pole plate packet and the actuator having a frame in which the two magnetic pole plate packets are arranged in a substantially form-fitting manner.

2. The actuator as claimed in claim 1, wherein the two magnets are each assigned two pole plates, the first and the second magnet, each with the two pole plates, forming at least one first and one second magnetic pole plate packet and the actuator having a frame in which the two magnetic pole plate packets are arranged in a substantially form-fitting manner.

3. The actuator as claimed in claim 1, wherein the two magnetic pole plate packets are not connected to the frame in a materially bonded manner.

4. The actuator as claimed in claim 1, wherein the two magnetic pole plate packets are fitted/arranged in the frame in a force-fitting and form-fitting manner.

5. The actuator as claimed in claim 1, wherein the frame has at least one first and one second recess on opposite outer surfaces, these recesses being designed to be, in particular partially or completely, delimited to the inside and an air gap in which the coil is arranged being formed between these recesses, a respective one of the magnetic pole plate packets being arranged in each of these two recesses in a form-fitting manner.

6. The actuator as claimed in claim 5, wherein the fixing of the two magnetic pole plate packets in the two recesses is formed/implemented at least by a form-fitting connection and by the mutual attraction force of the two magnets, in particular additionally the two recesses being formed as a press-fit with respect to the magnetic pole plate packets.

7. The actuator as claimed in claim 1, wherein the coil is arranged in a coil carrier in a fixed manner and the coil carrier with the coil is arranged in a feedthrough in the frame, which feedthrough forms the air gap, and this feedthrough is preferably formed substantially perpendicularly to the orientation of the two recesses in the magnetic pole plate packets, the coil carrier with the coil being arranged contactlessly in relation to the magnetic pole plate packets.

8. The actuator as claimed in claim 1, wherein the frame is formed from a plastic.

9. The actuator as claimed in claim 1, wherein the actuator has two spring elements which are designed and arranged such that they elastically fix the coil carrier on the two opposite sides, where it protrudes from the air gap.

10. The actuator as claimed in claim 9, wherein the spring elements are designed and arranged such that they are elastic in the direction of the feedthrough/the air gap and in particular substantially rigid with respect to other directions.

11. The actuator as claimed in claim 9, wherein the spring elements are each connected to the coil carrier in a form-fitting manner, in particular by means of fitting a lug or an arm of the spring element into a groove and/or recess in the coil carrier, the spring elements being designed and arranged such that they are resiliently supported on the opposite outer surfaces, on which the feedthrough openings of the air gap are arranged, in relation to an outer surface of the frame and/or in relation to an outer surface of a magnetic pole plate packet and are connected to the frame and/or at least one of the magnetic pole plate packets, in particular in a materially bonded manner.

12. The actuator as claimed in claim 9, wherein the spring elements are each supported by a spring arm on the two magnetic pole plate packets and are connected to them, in particular in a materially bonded manner.

13. The actuator as claimed in claim 1, wherein the actuator has a housing, in which the frame together with magnetic pole plate packets fastened/fitted in it and the coil carrier with the coil are arranged, the coil carrier being supported on two opposite inner surfaces of the housing and being mounted there and the frame with the magnetic pole plate packets being mounted such that it can move/vibrate in relation to the housing and the coil carrier.

14. The actuator as claimed in claim 13, wherein the housing is at least divided into two and these two housing parts are firmly connected to each other and the coil carrier is mounted on the two opposite inner surfaces such that it exhibits form-fitting and force-fitting mounting and fixing in the housing.

15. A method for producing/manufacturing an actuator as claimed in claim 1, a magnetic pole plate packet being fixed by a tool in each case and in this fixed state being fitted and inserted into the respective recess in the frame until the magnetic pole plate packet is in each case in contact with the boundary/projection/stop, adjacent to the air gap, of the respective recess, after which the fixing of the magnetic pole plate packets by the tools is released.

16. The method as claimed in claim 15, wherein the coil carrier, which is connected to the frame and/or the magnetic pole plate pair, is then fitted into a two-part housing, the coil carrier being compressed in its longitudinal direction, in particular substantially parallel to the air gap, by joining the two housing parts together, after which the two housing parts are firmly connected to each other, the compression or the press-fitting of the coil carrier being maintained in the housing.

17. The actuator as claimed in claim 2, wherein the two magnetic pole plate packets are not connected to the frame in a materially bonded manner.

18. The actuator as claimed in claim 1, wherein the coil is arranged in a coil carrier in a form fitting manner and the coil carrier with the coil is arranged in a feedthrough in the frame, which feedthrough forms the air gap, and this feedthrough is preferably formed substantially perpendicularly to the orientation of the two recesses in the magnetic pole plate packets, the coil carrier with the coil being arranged contactlessly in relation to the magnetic pole plate packets.

19. The actuator as claimed in claim 1, wherein the frame is formed from a fiber reinforced plastic.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1-12 relate to exemplary embodiments and are schematically illustrated.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0045] An exemplary actuator has a predominantly symmetrical structure of pole plates 5 and magnets 6, which has a double air gap with two predominantly inversely oriented magnetic fields. In order to achieve this by way of example, the two magnets are arranged inversely with respect to each other in their direction of magnetization. The at least one substantially rectangular coil is arranged in the air gap such that its outgoing and returning windings interact with the positively or negatively oriented magnetic fields, as a result of which a force excitation is produced by means of Lorentz force in the case of a current-carrying coil.

[0046] The exemplary design of the arrangement allows adhesive-free assembly. On the one hand, the frame 1 allows the adhesive-free mounting of the pole plates 5 and the magnets 6 by way of guiding them during assembly and positioning them after assembly. On the other hand, joining the upper housing shell or housing half 22 and the lower housing shell 23 under a preload allows force-fitting joining with the spring elements 18 and the coil assembly 14, comprising the coil carrier and the coil.

[0047] The frame 1 provides, by way of example, the capability to guide the pole plates 5 and the magnets 6 over the side walls as well as the upper and lower boundaries of the frame during assembly. The pole plates 5 and the magnets 6 are inserted, for example, as far as a geometric stop, which is embodied as a spacer bar 4. In an exemplary embodiment in which a respective magnet 6 with two pole plates 5, called assembly A 9 or magnetic pole plate packet, is inserted into both sides of the frame 1 and the polarization directions of the magnets 6 are inverted (called assembly B 10), a magnetic force 12 acts between the opposing pole plates of the two assembles A 9 or the magnetic pole plate packets. In addition, a magnetic force 11 also acts between the magnets 6 and pole plates 5 of the respective assembly A 9. This causes all pole plates 5 and magnets 6 to attract each other such that they are fixed in this arrangement, positioned by the frame 1. In the preferred case of manufacture of the frame 1 by means of plastic injection molding, the demolding slopes of the injection molding tool have a positive effect on the fixing of the pole plates 5 and magnets 6 since the region of the insert into the frame 1 thus narrows as the insert length increases and additionally mechanically clamps the pole plates 6 and the magnets 5.

[0048] Recesses 3 in the frame 1 allow, by way of example, insertion of the assemblies A 9, each consisting of pole plates 5 and magnets 6, by means of an assembly tool 13. Optional mounting chamfers 27 on the frame 1 can facilitate insertion of the respective assemblies A 9 in assembly step A 7.

[0049] The frame 1, into which the pole plates 5 and the magnets 6 are inserted for example, is connected by way of example via the spring elements 18 to the upper housing shell 22 and the lower housing shell 23. At least 1 stop buffer 28 is fitted to each of the surfaces of the frame 1 that face the spring elements 18, the stop buffer mitigating the mechanical impact in the event of a sharp deflection of the frame 1 in relation to the housing shells 22, 23. In this case, the stop buffer 28 can be fully integrated into the frame 1 and manufactured from the same material, but may also be an additional component, which is connected to the frame 1, for example, by an adhesive connection.

[0050] In exemplary assembly step C 15, the coil assembly 14, consisting of at least one coil 16 and at least one coil carrier 17, is inserted through the slot 2 into the frame 1.

[0051] The spring elements 18 are fitted to the coil assembly 14 in assembly step D 21, for example. The spring elements 18 rest on the end face of the coil assembly 14. In this case, the spring elements 18 have recesses at those points at which the coil assembly 14 has mounting lugs 19, in order to thereby allow positioning. The spring elements 18 are connected to the pole plates 5 via coupling points 20. The spring elements 18 are preferably welded to the pole plates 5. As a preferred alternative, the spring elements 18, instead of being connected to the pole plates 6, are directly connected to the frame 1, for example by means of hot caulking of the plastic of the frame 1.

[0052] The frame 1, into which the pole plates 5 and the magnets 6 are inserted, is connected to the coil assembly 14, for example, via the spring elements 18. The upper housing shell 22 and the lower housing shell 23 are connected in the separating plane 26. The upper housing shell 22 and the lower housing shell are joined under a preload, so that a static compressive force 25 is produced. The static compressive force 25 acts between the upper housing shell 22 and the lower housing shell 23, as a result of which the coil assembly 14, together with the spring elements 18, is clamped in the housing. This results in a force-fitting connection. The mounting lugs 19 of the coil assembly 14 can optionally additionally engage in housing grooves 24 in the upper housing shell 22 and the lower housing shell 23 in order to establish an additional form-fitting connection. Combining the two housing shells 22, 23 for producing the static compressive force 25 preferably takes place using a friction welding process or a laser welding process, which is particularly preferably executed with force-displacement-controlled machines.

[0053] Joining the upper housing shell 22 and the lower housing shell 23 in the separating plane 26 as in the example creates the static compressive force 25 which connects the spring elements 18 and the coil assembly 14 in a force-fitting manner. A compensating layer 29 composed of elastic material is preferably inserted between the spring elements 18 and one of the housing shells 22, 23 and/or between the spring elements 18 and the coil assembly 14, as a result of which the static compressive force 25 is introduced in a manner more evenly distributed over the force-transmitting surfaces. The compensating layer can be composed of plastic, elastomers, silicones or rubber, for example. A perforated and/or curved metal version (e.g.: leaf spring, plate spring) is also possible.

[0054] FIG. 1: Exemplary embodiment of a frame 1, which has slots 2 for passing a coil and/or a coil carrier through, recesses 3 for clearing space for assembly tools, and spacer bars 4 for positioning or aligning magnets and pole plates. The frame 1 can optionally have, as an assembly aid, mounting chamfers 27 which can be made on some or all of the insert edges.

[0055] FIG. 2: Exemplary embodiment of a frame 1, which surrounds the pole plates 5 and the magnets 6. The in each case at least one pole plate 5 touches the at least one magnet 6 on at least one of its sides, optionally also via a thin intermediate layer, such as an adhesive layer for example. The frame 1 is embodied such that it can accommodate at least one assembly comprising the at least one pole plate 5 and the at least one magnet and completely or partially surrounds it on at least 3 sides.

[0056] FIG. 3: Exemplary embodiment of the mounting of pole plates 5 and magnets 6 in a frame 1. In assembly step A 7, the at least one pole plate 5 is connected to the at least one magnet 6, as a result of which the assembly A 9 is produced. The connections in assembly step A 7 can be established, for example, by means of adhesive connection or in an adhesive-free manner by way of the magnetic attraction force between the pole plate 5 and the magnet 6. At the time of assembly step A 7, the magnets can selectively optionally already be pre-magnetized or be in an unmagnetized state. The joined assembly A 9 is inserted into the frame 1 in assembly step B 8, as a result of which the assembly B 10 is created. The connections in assembly step B 8 can be established, for example, by means of adhesive connection or in an adhesive-free manner by way of the magnetic attraction force between the pole plate 5 and the magnet 6.

[0057] FIG. 4: Sectional illustration through an exemplary embodiment of a frame 1 with pole plates 5 and magnets 6. The magnetic forces within the assembly A 11 hold the at least one pole plate 5 and the at least one magnet 6 together. The magnetic forces within the assembly B 12 ensure that the pole plates and the magnets of the respective assemblies A are attracted to each other. In this case, the frame 1 positions the pole plates 5 and magnets 6 in relation to each other and aligns them. The adjacent assemblies A are spaced apart in the frame 1 by at least one spacer bar 4. The entire assembly B is joined and held by way of combining the magnetic attraction forces 11, 12 and the frame 1.

[0058] FIG. 5: Exemplary embodiment of the process of mounting pole plates 5 and magnets 6 into the frame 1. Here, the assembly tools 13 grab the stack comprising the at least one magnet 6 and the at least one pole plate 5 (assembly A 9). On the basis of assembly step B 8, the at least one magnet 6 and the at least one pole plate 6 are inserted into the frame 1. The recesses 3 in the frame 1 allow engagement of the assembly tool 13.

[0059] FIG. 6: Sectional illustration through an exemplary embodiment of a frame 1 with pole plates 5 and magnets 6. In assembly step C 15, the coil assembly 14, consisting of at least one coil 16 and at least one coil carrier 17, is inserted into the frame 1 through the slot 2.

[0060] FIG. 7: Exemplary embodiment of an actuator with spring elements 18. The spring elements 18 are fitted to the coil assembly 14 in assembly step D 21. The spring elements 18 rest on the end face of the coil assembly 14. In this case, the spring elements 18 have recesses at those points at which the coil assembly 14 has mounting lugs 19, in order to thereby allow positioning. The spring elements 18 are connected to the pole plates 5 via coupling points 20.

[0061] FIG. 8: Sectional illustration through an exemplary embodiment of an actuator. The frame 1, into which the pole plates 5 and the magnets 6 are inserted, is connected to the coil assembly 14 via the spring elements 18. The upper housing shell 22 and the lower housing shell 23 are connected in the separating plane 26. The upper housing shell 22 and the lower housing shell are joined under a preload, so that a static compressive force 25 is produced. The static compressive force 25 acts between the upper housing shell 22 and the lower housing shell 23, as a result of which the coil assembly 14, together with the spring elements 18, is clamped in the housing. This results in a force-fitting connection. The mounting lugs 19 of the coil assembly 14 can optionally additionally engage in housing grooves 24 in the upper housing shell 22 and the lower housing shell 23 in order to establish an additional form-fitting connection.

[0062] FIG. 9: Sectional illustration through an exemplary embodiment of an actuator. The frame 1, into which the pole plates 5 and the magnets 6 are inserted, is connected to the upper housing shell 22 and the lower housing shell 23 via the spring elements 18. At least 1 stop buffer 28 is fitted to each of the surfaces of the frame 1 that face the spring elements 18, the stop buffer mitigating the mechanical impact in the event of a sharp deflection of the frame 1 in relation to the housing shells 22, 23.

[0063] FIG. 10: Sectional illustration through an exemplary embodiment of an actuator. Joining the upper housing shell 22 and the lower housing shell 23 in the separating plane 26 creates the static compressive force 25 which connects the spring elements 18 and the coil assembly 14 in a force-fitting manner. A compensating layer 29 composed of elastic material is preferably inserted between the spring element 18 and one of the upper housing shells 22, as a result of which the static compressive force 25 is introduced in a manner more evenly distributed over the force-transmitting surfaces.

[0064] FIG. 11 shows an exemplary embodiment of the frame 1, in which the recesses have a bevel, by way of example owing to the injection molding process, this bevel being shown in a more pronounced manner here for reasons of clarity. The bevel allows the magnetic pole plate packets 6, 5 to be mounted in a force-fitting manner, in addition to the form-fitting connection.

[0065] FIG. 12 shows an example analogous to that shown in FIG. 11, but without the bevel.

REFERENCE SIGNS

[0066] 1. Frame [0067] 2. Slot [0068] 3. Recess [0069] 4. Spacer bar [0070] 5. Pole plate [0071] 6. Magnet [0072] 7. Assembly step A [0073] 8. Assembly step B [0074] 9. Assembly A [0075] 10. Assembly B [0076] 11. Magnetic forces within assembly A [0077] 12. Magnetic forces within assembly B [0078] 13. Assembly tool [0079] 14. Coil assembly [0080] 15. Assembly step C [0081] 16. Coil [0082] 17. Coil carrier [0083] 18. Spring elements [0084] 19. Mounting lugs [0085] 20. Coupling points [0086] 21. Assembly step D [0087] 22. Upper housing shell [0088] 23. Lower housing shell [0089] 24. Housing grooves [0090] 25. Static compressive force [0091] 26. Separating plane [0092] 27. Mounting chamfers [0093] 28. Stop buffer [0094] 29. Compensating layer