Method for producing a sonic actuator, and actuator

Abstract

The invention relates to a method for producing a sonic actuator (10) and to a sonic actuator (10) produced by means of such a method. The sonic actuator (10) has a housing (12) comprising a first housing half (14) and a second housing half (16) and also an actuator unit (18) arranged in the housing (12), wherein the actuator unit (18) is clamped and fixed in the housing (12) between the housing halves (14, 16) with a pretensioning force (48). The method comprises the following steps: - providing the housing halves (14, 16) and the actuator unit (18); - positioning the actuator unit (18) between the housing halves (14, 16) and externally applying an assembly force (42) acting counter to the pretensioning direction to the housing halves (14, 16); - determining the pretensioning force (48) by measuring the external deformation of the first housing half (14) and / or of the second housing half (16) at at least one measuring position (52) due to the application of the assembly force (42); - increasing the assembly force (42) until an external deformation of the first housing half (14) and / or of the second housing half (16) corresponding to a defined pretensioning force (48) is achieved; - connecting the first housing half (14) and the second housing half (16) with a force fit in the pretensioning direction.

Description

[0001] Description

[0002] Method for producing a sound actuator and actuator

[0003] The invention relates to a method for producing a sound actuator, wherein the sound actuator comprises a housing with a first housing half and a second housing half, as well as an actuator unit arranged in the housing. The invention further relates to a sound actuator produced using such a method.

[0004] Actuators, in particular acoustic actuators, are known from the prior art, with which acoustic signals, for example tones, noises or vibrations, can be transmitted to components, in particular in a vehicle.

[0005] Such actuators comprise, for example, a coil arrangement with a coil through which a current can flow, as well as a magnet arrangement that is mounted for limited movement relative to the coil and can be excited to movement, in particular vibration, by applying current to the coil. The coil arrangement and the magnet arrangement can be installed or fixed in the housing as a prefabricated actuator unit.

[0006] The actuator unit must be securely fixed in the housing to ensure reliable transmission of vibrations from the actuator unit to the housing and to prevent unwanted noise, for example due to rattling of the actuator unit in the housing. It is known from the prior art that the housing can be manufactured from two housing halves. During the manufacturing process, the actuator unit is clamped between the housing halves with a defined preload force and the housing halves are then connected to one another so that the actuator unit is clamped between the housing halves with the preload force. This preload force must be sufficiently high to ensure reliable fixation of the actuator unit in the housing. Furthermore, it must be ensured that applying an excessive preload force does not lead to unwanted deformation of the actuator unit.However, a direct measurement of the preload force within the housing is very complex, since the housing is sealed during production, especially to make it dust and / or watertight.

[0007] The object of the invention is to provide a method for manufacturing a sonic actuator that enables reliable and as precise as possible determination and adjustment of the preload force acting between the housing and the actuator unit. Furthermore, the object of the invention is to provide such a sonic actuator.

[0008] To achieve this objective, a method for manufacturing a sound actuator is provided, wherein the sound actuator comprises a housing with a first housing half and a second housing half, as well as an actuator unit arranged in the housing, which is clamped and fixed in the housing between the housing halves with a preload force. The method comprises the following steps:

[0009] - Providing the housing halves and the actuator unit,

[0010] - Positioning the actuator unit between the housing halves and externally applying an assembly force to the housing halves in the direction of the preload force;

[0011] - Determination of the preload force by measuring the external deformation of the first housing half and / or the second housing half at at least one measuring position due to the application of the assembly force,

[0012] - Increasing the assembly force until an external deformation of the first housing half and / or the second housing half corresponding to a defined preload force is achieved,

[0013] - Connecting the first housing half and the second housing half so that forces can be absorbed between the first housing half and the second housing half. According to the invention, the preload force is not measured directly, for example by a sensor arranged inside the housing, but indirectly. Since the preload force applied to the actuator unit has to be absorbed by the housing, the application of the preload force leads to an elastic and / or plastic deformation of the housing, which is approximately linearly related to the applied preload force. This relationship is recorded and stored in advance, for example through appropriate experiments or tests. The preload force can then be determined indirectly from the measured deformation of the housing, without the preload force having to be measured inside the housing.

[0014] For example, the deformation can be measured only on one housing half, i.e. only the first housing half or the second housing half, which can enable simpler deformation measurement, for example with a sensor.

[0015] Optionally, the deformation can also be measured on both the first and second housing halves. This allows for a more precise measurement of the deformation and thus a more precise determination of the preload force. In particular, different deformations of the two housing halves can be better captured.

[0016] To measure the deformation of the first and / or second housing halves, only one sensor is required on one or each housing half. In particular, such a sensor measures the deformation in the direction of the preload force. However, deformation in another direction can also be measured if the preload force can be determined from this deformation.

[0017] However, multiple measuring positions can also be provided on the first housing half and / or the second housing half, where the external deformation is measured. By measuring the deformation at multiple measuring positions, it can be determined much more accurately, allowing a more precise determination of the preload force. In particular, this allows, for example, a three-dimensional deformation of the housing half to be measured.

[0018] Preferably, at least one measuring position is arranged symmetrically with respect to an axis running in the preload direction. For example, the housing is constructed symmetrically with respect to this axis of symmetry, for example, circular. With such a construction, the preload results in a substantially symmetrical deformation, which can be measured very precisely by measuring at a point of symmetry, for example, a center point.

[0019] The deformation of the first housing half and / or the second housing half can be measured using at least one sensor. In particular, the sensor can detect the deformation at at least one measuring position, and in particular at multiple measuring positions. Since the deformation is maintained after the application of an assembly force, the assembly force can, for example, be gradually increased, and the deformation at multiple measuring positions can be determined using one sensor.

[0020] Optionally, at least two, in particular several, sensors can be used to measure the deformation on each housing half, wherein the sensors can each measure the deformation at different measuring positions and / or the deformation at the same measuring position.

[0021] The sensors can use different measuring principles, for example, to eliminate system-related measurement errors or to combine the advantages of different measuring principles. In particular, measuring principles with different levels of accuracy can be used.

[0022] For example, at least one sensor can be a tactile sensor, an optical sensor, an acoustic sensor, in particular an ultrasonic sensor, an inductive sensor, and / or a capacitive sensor. Preferably, the first housing half and / or the second housing half have a pre-deformation formed to counteract the deformation caused by the pre-tensioning force, wherein the pre-deformation is designed such that it is compensated for by the deformation caused by the defined pre-tensioning force.

[0023] Furthermore, a particularly elastically deformable compensating element can be arranged between the first housing half and / or the second housing half and the actuator unit. This compensating element is elastically deformed when the assembly force is applied. The compensating element can distribute the applied preload forces more evenly across the force application area and supports the preservation of the preload force.

[0024] To solve the problem, a sound actuator manufactured using a method described above is also provided,

[0025] Further advantages and features can be found in the following description in conjunction with the attached drawings. These show:

[0026] Figure 1 is a sectional view through a sound actuator according to the invention

[0027] Figure 2 shows a detailed view of an actuator unit for the sound actuator from Figure 1;

[0028] Figures 3a to 3d show process steps for assembling the sound actuator from Figure 1;

[0029] Figure 4 is a schematic representation of the forces in the assembled sound actuator from Figure 1; and

[0030] Figure 5 is a detailed view of a second embodiment of a sound actuator.

[0031] Figure 1 shows a sound actuator 10, particularly for use in a vehicle. The sound actuator 10 can generate sound waves and transmit them, for example, to other components within the vehicle, making them acoustically perceptible to vehicle occupants.

[0032] The sound actuator has a housing 12 with a first housing half 14 and a second housing half 16, in which an actuator unit 18 is fixed. The housing halves 14, 16 are preferably made of plastic, for example ABS, PBT, PET, PLA; PA, PS), particularly preferably of a fiber-reinforced plastic, for example glass fiber or carbon fiber.

[0033] As can be seen in Figure 2, the actuator unit 18 has a frame 20 in which a plurality of magnetic plates 22 and pole plates 24 are received, forming a magnet arrangement 25 that provides a permanent magnetic field. The actuator unit 18 further has a coil frame 26 in which an excitation coil 28 is received. The frame 20 with the magnet arrangement 25 is mounted on the coil frame 26 via spring elements 30 for limited movement in an excitation direction 32. The coil frame 26 is received and fixed in a respective receptacle 34, 36 in the housing halves 14, 16.

[0034] By energizing the excitation coil 28, the frame 20 with the magnetic plates 22 and the pole plates 24 can be excited to oscillate in the excitation direction 32. These oscillations are transmitted via the coil frame 26 to the housing 12 and thus to other components.

[0035] The actuator unit 18 must be securely fixed in the housing 12 in order to absorb the forces generated during sound generation, particularly in the excitation direction 32, and to transmit them to the housing 12. For this reason, the actuator unit 18, in particular the coil frame 26, is fixed in the housing 12 with a preload force 48 (see Figures 3c and 3d). This preload force 48 must be adjusted very precisely. On the one hand, unwanted movement of the actuator unit 18 should be reliably prevented. On the other hand, an excessive preload force 48 can lead to damage to the actuator unit 18. To correctly adjust the preload force 48, the sound actuator 10 is mounted using the method shown in Figures 3a to 3d.

[0036] In a first method step (Figure 3a), the actuator unit 18 and the two housing halves 14, 16 are provided. The actuator unit 18 is positioned with the coil frame 26 in the receptacle 36 of the second housing half 16.

[0037] The first housing half 14 is then aligned over the second housing half 16 and the actuator unit 18 so that the receptacle 34 of the first housing half 14 is aligned with the coil frame 26. The first housing half 14 is then placed onto the second housing half so that the edge 38 of the first housing half 14 rests on the edge 40 of the second housing half 16 (Figure 3b). In this intermediate assembly state, the coil frame 26 or the actuator unit 18 can already rest in the receptacle 34 on the first housing half 14.

[0038] The edges 38, 40 are then sealed, for example by

[0039] Ultrasonic welding, laser welding, or another suitable method melts the metal, and an assembly force 42 is applied to the housing halves 14, 16, wherein the assembly force 42 is applied perpendicularly to the housing halves 14, 16 (Figure 3c). In particular, the assembly force 42 is applied in the corner regions 44, 46. This is necessary to enable deformation of the first housing half 14 and the second housing half 16, as explained below.

[0040] The assembly force 42 creates, on the one hand, a compressive force 47 between the edges 38, 40, which presses and / or deforms the molten edges 38, 40 against each other. Furthermore, a preload force 48 is created between the coil frame 26 and the actuator unit 18, which presses the actuator unit 18 into the receptacles 34, 36 and thus fixes it reliably and without play in the housing. The application of the assembly force 42 and the creation of the preload force 48 result in slight deformations of the housing halves 14, 16 (see Figure 4). These deformations of the housing halves 14, 16 are essentially directly and linearly dependent on the preload force 48, so that the magnitude of the preload force 48 can be determined from the deformation.

[0041] To measure the deformation, a sensor 50 is provided, which measures the deformation of the housing half 14, 16 at a measuring position 52 in the direction of the preload force. In the embodiment shown here, only one sensor 50 is shown on the second housing half 16. Additionally, a measuring position 52 and a sensor 50 can also be provided on the first housing half 14. In particular, several sensors 50 can also be provided on each of the housing halves 14, 16 in order to better measure the deformation of the respective housing half 14, 16.

[0042] The sensors 50 are preferably displacement sensors. The sensors 50 can be designed, for example, as tactile sensors, ultrasonic sensors, optical sensors, inductive sensors, or capacitive sensors. The optical sensor can be, for example, a laser sensor or a camera system. It is only necessary that the sensors 50 can detect the deformation of the housing halves 14, 16 or the magnitude of the deformation.

[0043] In particular, several sensors 50 with different measuring principles can be provided on each housing half 14, 16, for example, to reduce system-related disadvantages of a measuring principle or to enable redundant measurement. In particular, the sensors 50 can each detect the deformation at the same measuring position 52 and / or a separate sensor 50 can be provided for each measuring position 52.

[0044] Since the relationship between the deformation of the housing halves 14, 16 and the preload force 48 is known, the deformation at which the desired preload force 48 is reached can be determined. The assembly force 42 is increased during assembly until the deformation determined for the desired preload 48 is reached. Subsequently, in this state, the housing halves 14, 16 are connected to one another at the edges 38, 40, in particular in a force-fitting manner in the direction of the preload force, so that forces arising between the housing halves 14, 16 can be absorbed. In particular, the housing halves 14, 16 are pressed apart by the preload force 48, so that after the assembly force 42 is removed, tensile forces 56 arise between the housing halves 14, 16, in particular between the edges 38, 40, which are absorbed by the connection of the housing halves.In the embodiment described above, the edges 38, 40 can be joined by ending the melting process, i.e., ending the energy input, so that the edges 38, 40 solidify and join together.

[0045] For example, the housing halves 14, 16 are joined together by a welding or adhesive process. Welding can be performed, for example, by laser welding, ultrasonic welding, or friction welding. In particular, the housing halves 14, 16 are joined in a dust- and / or watertight manner, so that the actuator unit 18 is reliably protected.

[0046] The assembly force 42 can then be removed. Due to the connection of the housing halves 14, 16, the preload force 48 remains, so that the actuator unit 18 is reliably fixed and held in the housing 12. Once the joining process is complete, the external assembly force 42 is no longer effective. The internal preload force 48 remains conserved inside the housing 12 between the first housing half 14 and the second housing half 16.

[0047] In the embodiment shown here, the measuring position 52 is provided centrally on the second housing half 16 with respect to an axis of symmetry. Furthermore, a plurality of measuring positions 52 can be provided, which are in particular provided symmetrically on the housing half 14, 16. Optionally, the measuring positions 52 can also be arranged asymmetrically, as long as a deformation can be measured at the measuring positions 52, from which a direct conclusion about the preload force 42 is possible. In particular, a separate sensor 50 can be provided for each of the measuring positions 52. However, it is also possible for one sensor 50 to detect the deformations at several measuring positions 52.

[0048] Since the relationship between the preload force 48 and the resulting deformations of the housing half 14, 16 is known, the housing 12 can, for example, also have a pre-deformation which is designed such that the deformation due to the preload force 48 compensates for the pre-deformation, so that the housing 12 has a desired external shape after the application of the preload force 48 (Figure 5).

[0049] Optionally, an elastic compensating element 54 can be provided between the actuator unit 18 and the housing 12, which can additionally protect the actuator unit 18 from excessive preload forces 48. The compensating element 54 supports the maintenance of the preload force 48 and improves the reliability of the joining process through its elastic properties. In particular, the elastic properties can compensate for settlement of the plastic of the housing 12.

[0050] Furthermore, the compensating element 54 is designed so that it can compensate for geometric deviations or tolerances of the actuator unit 18 and / or the housing halves 14, 16.

[0051] The compensating element 54 preferably has a thickness between 0.4 mm and 4 mm and can fill the area between the receptacle 34, 36 and the actuator unit 18 completely or only partially. The compensating element is elastic, for example made of plastic, elastomers, silicone, or rubber. The compensating element 54 is preferably made of a foamed, slotted, or perforated material. Alternatively, the compensating element 54 can also be a spring element, in particular made of metal, for example of slotted and / or curved metal, for example a leaf spring or a disc spring. In the embodiment of the method described above, the edges 38, 40 are melted by a suitable process and deformed when the assembly force is applied, wherein the connection of the housing half 14, 16 takes place by a re-solidification of the edges 38, 40.

[0052] However, it is also possible that no deformation occurs or is required at the edges 38, 40 when the assembly force 42 is applied, for example, because the edges 38, 40 are not resting on one another at this time. For example, the edges 38, 40 may still be spaced apart from one another at this time and only come into contact with one another when the assembly force 42 is applied. Alternatively, the housing halves 14, 16 are designed such that the edges 38, 40 are displaced relative to one another but do not rest on one another.

[0053] In principle, the first housing half 14 and / or the second housing half 16 are deformed by the assembly force 42 or the preload force 48. As soon as this deformation corresponds to a desired preload force 48, the housing halves 14, 16, in particular the edges 38, 40, are fixed relative to one another, in particular connected, whereby the forces generated by the preload force 48 are absorbed in the housing 12 by this connection and the preload force 48 is maintained. For example, the edges 38, 40 can also be glued or fixed relative to one another by other suitable joining methods, for example mechanical joining methods. In particular, additional fixing elements can also be used.

[0054] List of reference symbols

[0055] 10 sound actuator

[0056] 12 housings

[0057] 14 first housing half

[0058] 16 second housing half

[0059] 18 Actuator unit

[0060] 20 frames

[0061] 22 Magnetic plate

[0062] 24 Pole plate

[0063] 25 Magnet arrangement

[0064] 26 spool frames

[0065] 28 Excitation coil

[0066] 30 spring elements

[0067] 32 Excitation direction

[0068] 34 recording

[0069] 36 recording

[0070] 38 Edge of the first housing half

[0071] 40 Edge of the second housing half

[0072] 42 assembly workers

[0073] 44 Corner area of ​​the first housing half

[0074] 46 Corner area of ​​the second housing half

[0075] 47 compressive force

[0076] 48 Preload force

[0077] 50 sensors

[0078] 52 measuring position

[0079] 54 Compensating element

[0080] 56 tensile forces

Claims

Patent claims 1. A method for producing a sound actuator (10), wherein the sound actuator (10) has a housing (12) with a first housing half (14) and a second housing half (16) and an actuator unit (18) arranged in the housing (12), wherein the actuator unit (18) is clamped and fixed in the housing (12) between the housing halves (14, 16) with a prestressing force (48), comprising the following steps: - Providing the housing halves (14, 16) and the actuator unit (18), - positioning the actuator unit (18) between the housing halves (14, 16) and externally applying an assembly force (42) to the housing halves (14, 16), - determining the preload force (48) by measuring the external deformation of the first housing half (14) and / or the second housing half (16) at at least one measuring position (52) due to the application of the assembly force (42), - increasing the assembly force (42) until an external deformation of the first housing half (14) and / or the second housing half (16) corresponding to a defined preload force (48) is achieved, - Connecting the first housing half (14) and the second housing half (16) so that forces can be absorbed between the first housing half (14) and the second housing half (16).

2. Method according to claim 1, characterized in that the deformation is measured only on the first housing half (14) or the second housing half (16).

3. Method according to claim 1, characterized in that the deformation is measured on both the first housing half (14) and the second housing half (16).

4. Method according to one of the preceding claims, characterized in that on the first housing half (14) and / or the second housing half (16) several measuring positions (52) are provided at which the external deformation is measured.

5. Method according to one of the preceding claims, characterized in that the at least one measuring position (52) is arranged symmetrically with respect to an axis running in the preload direction.

6. Method according to one of the preceding claims, characterized in that the measurement of the deformation of the first housing half (14) and / or the second housing half (16) is carried out in each case with at least one sensor (50).

7. The method according to claim 6, characterized in that at least two sensors (50) on the first housing half (14) and / or the second housing half (16) measure the deformation at at least one measuring position, wherein the sensors (50) each have different measuring principles.

8. Method according to one of claims 6 and 7, characterized in that the sensor (50) is a tactile sensor, an optical sensor, an acoustic sensor, in particular an ultrasonic sensor, an inductive sensor and / or a capacitive sensor.

9. Method according to one of the preceding claims, characterized in that the first housing half (14) and / or the second housing half (16) have a pre-deformation, wherein the pre-deformation is designed such that it is substantially compensated by the deformation due to the defined pre-tensioning force (48).

10. Method according to one of the preceding claims, characterized in that an elastic compensating element (54) is arranged between the first housing half (14) and / or the second housing half (16) and the actuator unit (18).

11. Sound actuator (10), wherein the sound actuator (10) has a housing (12) with a first housing half (14) and a second housing half (16) and an actuator unit (18) arranged in the housing (12), wherein the actuator unit (18) is clamped and fixed in the housing (12) between the housing halves (14, 16) with a prestressing force (48) acting in a prestressing direction, wherein the sound actuator (10) is produced according to a method of the preceding claims.

12. Sound actuator according to claim 11, characterized in that the actuator unit has a coil frame (26) fixed in the housing (12) with an excitation coil (28) and a magnet arrangement mounted so as to be movable to a limited extent relative to the coil frame (26).

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