Ultrasonic sensor and vehicle

Abstract

The present invention relates to an ultrasonic sensor (5) and a vehicle, wherein the ultrasonic sensor (5) has: a housing (10), a diaphragm canister (20) and a piezoelectric transducer (30), wherein the diaphragm canister (20) has a substantially cylindrical wall (22) and a vibrating diaphragm (25) and is constructed based on a polymer, wherein the piezoelectric transducer (30) is integrated in the diaphragm (25) in such a way that the piezoelectric transducer (30) is completely covered by the polymer of the diaphragm (25), and wherein the diaphragm canister (20) is at least partially inserted into the housing (10) and fixed to the housing (10).

Description

Technical Field

[0001] The present invention relates to an ultrasonic sensor and a vehicle having such an ultrasonic sensor. Background Technology

[0002] Ultrasonic sensors, as known in the prior art, operate on the principle of transmitting and receiving sound waves. These sound waves are radiated in an inaudible range by means of a vibrating diaphragm, typically made of aluminum, and can be reflected back to the ultrasonic sensor by objects in the surrounding environment.

[0003] The reflected sound waves can be received by a diaphragm and converted into an electrical signal by a transducer. Based on the electrical signal, the running time of the signal can be measured to determine the distance to objects in the environment surrounding the ultrasonic sensor.

[0004] Furthermore, in connection with using ultrasonic sensors as environmental sensors for a vehicle, a coating that faces the environment is typically applied to the diaphragm of the ultrasonic sensor so that these ultrasonic sensors can be integrated as inconspicuously as possible into the vehicle's bumper and / or in areas with a different arrangement, through the corresponding color coordination of the coating.

[0005] Furthermore, it is known that polymers are used instead of aluminum in the manufacture of ultrasonic sensors, and the use of polymers can also involve the construction of the diaphragm itself.

[0006] DE102017216868A1 discloses an acoustic transducer, particularly for ultrasonic transducers, having a housing, a decoupling element, a diaphragm canister, and an electroacoustic transducer element, wherein at least a portion of the diaphragm canister and the housing is made of plastic material, and wherein the decoupling element is integrated in the diaphragm canister, particularly in the wall of the diaphragm canister and / or in at least a portion of the housing.

[0007] DE102015115419A1 discloses an ultrasonic sensor for a motor vehicle, having a diaphragm, the diaphragm having a diaphragm bottom and a diaphragm wall, wherein the diaphragm bottom has a front side pointing in the direction of emission of ultrasonic signals from the ultrasonic sensor and a back side opposite to the front side. Summary of the Invention

[0008] According to a first aspect of the invention, an ultrasonic sensor is proposed, and in particular an ultrasonic sensor for a vehicle is proposed, the ultrasonic sensor having a housing, a diaphragm canister and a piezoelectric transducer.

[0009] The diaphragm can has substantially cylindrical walls and a vibrating diaphragm and is constructed based on a polymer (e.g., polyamide, epoxide, etc.), which is advantageously a fiber-reinforced polymer (e.g., using carbon fiber, glass fiber, etc.), but is not limited thereto. "Substantially cylindrical walls" should also be explicitly understood to mean a diaphragm can with flanges and / or reinforcing elements and / or fixing elements and / or recesses and / or protrusions and / or a certain degree of inclination and / or extension and / or deformation of the outer peripheral surface, etc.

[0010] Furthermore, the diaphragm can is integrally formed, for example, as an injection-molded part.

[0011] The preferred disc-shaped piezoelectric transducer is integrated into the diaphragm in such a way that the transducer is completely covered by the polymer of the diaphragm. Where the diaphragm can is constructed as an injection-molded part, the piezoelectric transducer can be directly embedded into the diaphragm during the injection molding process. This also provides the advantage that the diaphragm can, together with the piezoelectric transducer, can be constructed in a single manufacturing step, thereby reducing manufacturing and / or material costs, for example. Furthermore, by omnidirectionally surrounding the piezoelectric transducer with the polymer of the diaphragm, a particularly reliable connection is established between the diaphragm and the piezoelectric transducer.

[0012] Furthermore, the diaphragm canister is at least partially inserted into and fixed to the housing, wherein the fixing to the housing is preferably indirectly via a decoupling element configured to provide at least partial mechanical decoupling between the housing and the diaphragm canister, so as to keep, for example, vibrations acting on the ultrasonic sensor as far away as possible from the piezoelectric transducer, to ensure the least possible interference-free operation of the ultrasonic sensor. This does not preclude the possibility that the diaphragm canister could be directly connected to the housing without such a decoupling element.

[0013] The decoupling element is constructed, for example, as a silicon ring, which is arranged on and / or integrated in a fixing element to be connected to the housing, and the silicon ring fixes the diaphragm canister while the ultrasonic sensor is assembled inside the housing.

[0014] The dependent claims illustrate preferred further extensions of the invention.

[0015] In an advantageous configuration of the invention, the piezoelectric transducer is covered by a polymer layer on one or both sides of the diaphragm in the direction of the main receiving axis or the main transmitting axis (i.e., a direction typically perpendicular to the diaphragm surface). The thickness of the polymer layer is equivalent to one-quarter or an odd multiple of the wavelength of the desired resonant frequency of the ultrasonic sensor. In this way, a resonant effect can be achieved, which correspondingly enhances the signal to be transmitted and / or received in the resonant frequency range. It is particularly advantageous that the polymer layer of such thickness is disposed not only on the side of the diaphragm facing the surrounding environment but also on the side of the diaphragm facing the interior space of the ultrasonic sensor housing. This explicitly does not preclude the possibility that only the side of the diaphragm facing the surrounding environment or only the side facing the interior space of the housing has such a thickness, while the respective other sides have different thicknesses, for example, to achieve different resonant characteristics of the ultrasonic sensor.

[0016] Particularly advantageous is that the diaphragm has a coating with a thickness of up to 300 µm, preferably up to 200 µm, and especially preferably up to 70 µm, on the side facing the surrounding environment of the ultrasonic sensor. This coating is, for example, a paint coating and / or a powder coating, and can also be used for optical adaptation of the outwardly visible diaphragm surface (e.g., color coordination with the mounting area of ​​the ultrasonic sensor on the vehicle) and / or for mechanical protection of the diaphragm and / or for targeted adaptation of the diaphragm's elastic modulus. Adapting the elastic modulus can, for example, affect the resonant frequency of the ultrasonic sensor. Furthermore, using a diaphragm made of polymer yields a particular advantage: the potential need for corrosion protection and / or passivation of the diaphragm surface can be eliminated because the diaphragm is not made of aluminum or a comparable metal. This means that the coating thickness can be smaller compared to the coating of a conventional aluminum diaphragm, thus achieving material and cost savings on the one hand, and greater flexibility in setting the coating thickness on the other, thereby resulting in greater flexibility in setting the resonant characteristics of the ultrasonic sensor.

[0017] In a particularly advantageous configuration of the invention, the electrical contact of the piezoelectric transducer is made via a first and a second electrical conductor, which are guided at least partially through the polymer of the diaphragm can to first and second electrical contacts. These contacts are exposed on the diaphragm can for electrical contact with the housing, wherein the electrical contact of the housing is preferably configured to transmit and / or receive electrical signals between the piezoelectric transducer and circuitry arranged in the housing, the circuitry being configured to generate the transmitted signals and / or process the received signals. The first and / or second electrical conductors are constructed, for example, as insulated or uninsulated wires, or otherwise. In the preferred case where the polymer used to construct the diaphragm can is a non-conductive polymer, the electrical contact made by means of the first and second electrical conductors can be constructed particularly simply and at low cost because the electrical contact does not need to be insulated relative to the conductive base material of the diaphragm can (e.g., aluminum) used in the prior art to avoid short circuits. Another advantage arises from the fact that the two electrical conductors, guided at least partially through the polymer and / or on the polymer surface of the diaphragm can, are constructed to be particularly insensitive to mechanical stress. Particularly preferably, the first and second electrical conductors are integrated directly into a single injection molding process for constructing the diaphragm can and / or diaphragm, similar to piezoelectric elements. The first and / or second electrical contacts are, for example, segments of the first and / or second conductors themselves and / or additionally, contact elements (e.g., contact surfaces or contact pads), which are constructed separately from and electrically connected to the first and / or second electrical conductors. These contacts can, for example, be constructed in the same single injection molding process described above.

[0018] Advantageously, the first and / or second electrical contacts are arranged on the inner surface of the diaphragm can wall and / or the outer surface of the diaphragm can wall and / or the end face of the diaphragm can facing the inner side of the housing, without thus restricting the arrangement position of the first and / or second contacts on the diaphragm can. Accordingly, for example, it is also possible to arrange the first contact on the inner surface of the diaphragm can wall and the second contact on the outer surface of the diaphragm can, and the respective arrangement positions can be combined differently therein.

[0019] Preferably, the contact between the first and second electrical contacts of the diaphragm canister and the housing is made via housing contacts disposed on the housing, corresponding to the arrangement positions of the first and second contacts. This electrical contact between the diaphragm canister and the housing is advantageously made such that it is implicitly established during the assembly of the ultrasonic sensor when the diaphragm canister is secured to the housing. This significantly shortens the manufacturing process compared to the prior art, where a welding process is typically required to connect the wires electrically connected to the piezoelectric transducer to the corresponding contacts on the housing.

[0020] In another advantageous configuration of the invention, contact between the first and second electrical contacts of the diaphragm can and the housing is achieved via a decoupling element that is at least partially conductive, thereby mechanically decoupling the diaphragm can and the housing in the assembled state. This decoupling element is preferably an embodiment of the decoupling element described above (or a different decoupling element), in which the decoupling element has separate conductive sections configured to allow the two lines of the piezoelectric transducer to be individually connected to the housing. The conductive sections are constructed, for example, by means of a conductive coating on the decoupling element and / or by means of wires integrated into the decoupling element and / or arranged on the surface of the decoupling element, and / or constructed differently therefrom.

[0021] Advantageously, electrical contact between the diaphragm can and the housing is established via spring contacts (e.g., as Pogo pins, etc.) and / or brazing and / or fusion welding connections.

[0022] According to a second aspect of the invention, a vehicle is provided having at least one ultrasonic sensor according to any one of the preceding claims. The vehicle is preferably constructed as a road vehicle (e.g., a passenger car, transport vehicle, truck, bus, motorcycle, etc.), a rail vehicle, or otherwise. Particularly advantageous is that the vehicle has multiple such ultrasonic sensors, configured, for example, to detect the vehicle's surrounding environment. Such environmental detection is used, for example, for the vehicle's (partial) automated driving system and / or for the vehicle's driver assistance system. These features, combinations of features, and the resulting advantages so clearly correspond to the features, combinations of features, and the resulting advantages implemented in conjunction with the first aspect of the invention that reference is made to the above description to avoid repetition. Attached Figure Description

[0023] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The drawings show: Figure 1 : A schematic diagram of an exemplary embodiment of the ultrasonic sensor according to the present invention; Figure 2 : A schematic diagram of an exemplary embodiment of the diaphragm can according to the present invention; Figure 3 : A schematic diagram of another exemplary embodiment of the diaphragm can according to the present invention; Figure 4 : A schematic diagram of another exemplary embodiment of the diaphragm can according to the present invention; and Figure 5 : A schematic diagram of an exemplary embodiment of a vehicle according to the present invention. Detailed Implementation

[0024] Figure 1A schematic diagram illustrating an exemplary embodiment of an ultrasonic sensor 5 according to the present invention is shown, the ultrasonic sensor having a housing 10 made of polymer, a diaphragm canister 20 also made of polymer, a piezoelectric transducer 30, and a fixing element 90 also made of polymer. The various components are shown here in a separated state (in a partially exploded view) for better overview.

[0025] The ultrasonic sensor 5 is configured herein as an example ultrasonic sensor 5 for a passenger vehicle.

[0026] The diaphragm can 20 has a generally cylindrical wall 22 and a vibrating diaphragm 25 and is integrally constructed by injection molding. During the manufacturing process of the diaphragm can 20, a piezoelectric transducer 30 is integrated into the diaphragm 25 during injection molding, such that the piezoelectric transducer 30 is covered on both sides by a polymer layer 40 of the diaphragm 25.

[0027] During the manufacture of the ultrasonic sensor 5, the diaphragm can 20 is inserted into the housing 10 with its end face 27 facing forward and is fixed to the housing 10 by means of a fixing element 90. In order to mechanically decouple the diaphragm can 20 from the housing 10, a decoupling element 80 configured as a silicon ring is provided on the fixing element 90.

[0028] In addition, the surface of the diaphragm 25 facing the surrounding environment has a coating 50, which has a thickness of 70 µm.

[0029] Figure 2 A schematic diagram illustrating an exemplary embodiment of the membrane canister 20 according to the present invention is shown. Due to the... Figure 1 The membrane canister 20 shown in the image and in Figure 2 There are many similarities between the diaphragm canisters 20 shown in the figures, so to avoid repetition, only the differences between these figures will be described below.

[0030] Figure 2 The diaphragm can 20 has a first electrical conductor 60 configured as a wire, which passes through the polymer of the diaphragm can 20 and is guided to a first electrical contact 70 (here, a contact pad) on the end face 27 of the diaphragm can 20 and electrically connects the first connector (not shown) of the piezoelectric transducer 30 to the first electrical contact 70.

[0031] also, Figure 2 The diaphragm can 20 has a second electrical conductor 65 configured as a wire, which is guided through the polymer of the diaphragm can 20 to a second electrical contact 75 (also a contact pad here) on the end face 27 of the diaphragm can 20 and electrically connects the second connector (not shown) of the piezoelectric transducer 30 to the second electrical contact 75.

[0032] The first electrical contact 70 and the second electrical contact 75 of the diaphragm can 20 are connected to the housing 10 (see...) Figure 1 The contact is made via housing contacts disposed on the housing 10, corresponding to the arrangement positions of the first contact 70 and the second contact 75. The housing contacts are configured, for example, as spring contacts, to ensure a reliable electrical connection.

[0033] Figure 3 A schematic diagram illustrating another exemplary embodiment of the diaphragm canister 20 according to the present invention is shown, the diaphragm canister being in... Figure 2 The only difference between the membrane canister 20 shown is: Figure 3 The electrical contacts 70 and 75 of the diaphragm can 20 are arranged on the inner surface of the wall 22. Because... Figure 3 The remaining structure of the diaphragm canister 20 shown is the same as that in Figure 2 The same as shown in the figure, so to avoid repetition, please refer to the figure. Figure 2 The description.

[0034] Figure 4 A schematic diagram of another exemplary embodiment of the diaphragm can 20 according to the present invention is shown, wherein the electrical conductors 60, 65 and the electrical contacts 70, 75 of the diaphragm can 20 are not shown here for better overview.

[0035] Depend on Figure 4 As can be seen, the polymer layer 40 of the diaphragm 25, facing the environment surrounding the diaphragm canister 20, surrounds the piezoelectric transducer 30 on one side. This polymer layer has a thickness d1, which corresponds to the thickness of the ultrasonic sensor 5 (see, for example, [link to original text]). Figure 1 The desired resonant frequency is one-quarter of the wavelength, and the diaphragm canister 20 is arranged in the ultrasonic sensor.

[0036] Furthermore, it can be seen that the polymer layer 40 of the diaphragm 25 surrounds the piezoelectric transducer 30 on the side opposite to the aforementioned side. This polymer layer has a thickness d2, which is also equivalent to the thickness of the ultrasonic sensor 5 (see, for example, [link to article]). Figure 1 The desired resonant frequency is one-quarter of the wavelength, and the diaphragm canister 20 is arranged in the ultrasonic sensor.

[0037] Based on the selected thicknesses d1 and d2, advantageous amplification of the transmitted and received signals of the ultrasonic sensor 5 can be achieved within the resonant frequency range of the ultrasonic sensor.

[0038] Figure 5 A schematic diagram of an exemplary embodiment of a vehicle 100 according to the present invention is shown. The vehicle is configured as a passenger car and has an ambient environment detection system 110, which is informationally connected to a plurality of ultrasonic sensors 5 according to the present invention for implementing the functions of a driver assistance system (e.g., parking assistance) based on the ultrasonic sensors 5.

Claims

1. An ultrasonic sensor (5) having: -Shell (10) - Membrane canister (20), and - Piezoelectric transducer (30). in, - The diaphragm canister (20) has substantially cylindrical walls (22) and a vibrating diaphragm (25) and is constructed based on a polymer. - The piezoelectric transducer (30) is integrated into the diaphragm (25) in such a way that the piezoelectric transducer (30) is completely covered by the polymer of the diaphragm (25), and - The diaphragm canister (20) is at least partially inserted into the housing (10) and fixed to the housing (10).

2. The ultrasonic sensor (5) according to claim 1, wherein, - The diaphragm canister (20) is manufactured by injection molding, in which the piezoelectric transducer (30) is integrated into the diaphragm (25), and / or - The polymer of the membrane canister (20) is a fiber-reinforced polymer.

3. The ultrasonic sensor (5) according to any one of the preceding claims, wherein, The piezoelectric transducer (30) is covered by the polymer of the diaphragm (25) as follows: the piezoelectric transducer (30) is covered on one or both sides of the main receiving axis or the main transmitting axis, and the thickness (d1, d2) of the polymer layer is equivalent to one-quarter or an odd multiple of the wavelength of the desired resonant frequency of the ultrasonic sensor (5).

4. The ultrasonic sensor (5) according to any one of the preceding claims, wherein, The diaphragm (25) has a coating (50) with a thickness of up to 300 µm, preferably up to 200 µm and especially preferably up to 70 µm on the side facing the surrounding environment of the ultrasonic sensor (5).

5. The ultrasonic sensor (5) according to any one of the preceding claims, wherein, The electrical contact of the piezoelectric transducer (30) is made via a first electrical conductor (60) and a second electrical conductor (65) that are guided at least partially through the polymer of the diaphragm can (20) to a first electrical contact (70) and a second electrical contact (75) that are exposed on the diaphragm can (20) for electrical contact with the housing (10).

6. The ultrasonic sensor (5) according to claim 5, wherein, The first electrical contact (70) and / or the second electrical contact (75) are arranged in - On the inner surface of the wall (22) of the diaphragm canister (20), and / or -On the outer surface of the wall (22) of the diaphragm canister (20), and / or - On the end face (27) of the diaphragm can (22) facing the inside of the shell.

7. The ultrasonic sensor (5) according to claim 5 or 6, wherein, The first electrical contact (70) and the second electrical contact (75) of the diaphragm canister (20) make contact with the housing (10) via housing contacts disposed on the housing (10) corresponding to the arrangement positions of the first contact (70) and the second contact (75).

8. The ultrasonic sensor (5) according to any one of claims 5 to 7, wherein, The first electrical contact (70) and the second electrical contact (75) of the diaphragm can (20) are made in contact with the housing (10) via a decoupling element (80) that is at least partially conductive, thereby mechanically decoupling the diaphragm can (20) and the housing (10) in the assembled state.

9. The ultrasonic sensor (5) according to any one of claims 5 to 8, wherein, The electrical contact between the diaphragm can (20) and the housing (10) is established via spring contacts and / or brazing and / or fusion welding connections.

10. A vehicle (100) having at least one ultrasonic sensor (5) according to any one of the preceding claims.

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