Ultrasonic sensors for motor vehicles.

Abstract

The invention relates to an ultrasonic sensor system (1) for a motor vehicle, comprising a sensor housing (2) and a pan-shaped membrane (5) connected to the sensor housing (2), the membrane (5) having a membrane bottom (6) for transmitting and / or receiving ultrasonic signals and a membrane wall (7) connected to the membrane bottom (6) and partly extending into the sensor housing (2). In the housing interior space of the housing segment (9) facing the membrane bottom (6) of the sensor housing (2) a first encapsulation material (10) is arranged, which fills the housing interior space. According to the invention, the first encapsulation material (10) at least partly extends into the membrane interior space of the membrane (5) surrounded by the membrane wall (7), the membrane (5) being geometrically connected to the sensor housing (2) by the first encapsulation material (10).

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic sensor system for a motor vehicle, comprising a sensor housing and a pan-shaped membrane connected to the sensor housing, the membrane having a membrane bottom for transmitting and / or receiving ultrasonic signals and a membrane wall connected to the membrane bottom, a portion of the membrane wall extending into the sensor housing, and a first encapsulant disposed within the housing interior space of the housing segment facing the membrane bottom, the first encapsulant filling the housing interior space. [Background technology]

[0002] Modern motor vehicles typically include a number of ultrasonic sensors associated with driver assistance devices, such as parking assistance systems and / or braking assistance systems, that provide information about the surroundings of the motor vehicle, particularly obstacles and objects in the surroundings, and the distance of the motor vehicle from these. Such ultrasonic sensors are located around the motor vehicle, at least in the front and rear regions of the vehicle, and are usually integrated into fairing components, particularly the bumper.

[0003] In this regard, such ultrasonic sensors are typically positioned within an opening or cutout in a motor vehicle fairing component such that the leading or front membrane bottom of the ultrasonic sensor's pan-shaped membrane is essentially aligned with the surface of the fairing component, but such that ultrasonic waves can be transmitted from and received at the membrane bottom during operation.

[0004] An ultrasonic sensor of the aforementioned type is known, for example, from DE 10 2006 028 214 A1. The ultrasonic sensor comprises an essentially cylindrical sensor housing and a pan-shaped membrane with a disk-shaped membrane bottom supported on the sensor housing, with a piezo element arranged inside the membrane bottom to vibrate the membrane so that it generates an ultrasonic signal. The membrane is surrounded on its outer circumferential side by an annular isolating element that separates the membrane from the sensor housing in terms of vibration. The membrane is supported on its housing side by an annular housing segment of the sensor housing that surrounds the outer circumferential side of the isolating element facing the sensor housing, with the isolating element and the housing segment being connected to each other via a snap mechanism. Additionally, an encapsulant is arranged in the interior space of the sensor housing to protect the ultrasonic sensor and its electrical components from moisture and dirt.

[0005] Such a configuration has the drawback that the number of parts and assembly steps are large, which results in complicated manufacturing and an increase in overall manufacturing costs. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] DE102006028214A1 Summary of the Invention [Problem to be solved by the invention]

[0007] SUMMARY OF THE INVENTION The problem to be solved by the present invention is therefore to disclose an improved configuration for an ultrasonic sensor that has a simplified structure and that has as few parts and as few assembly steps as possible in the manufacturing process. [Means for solving the problem]

[0008] This object is achieved by the teaching set forth in claim 1. Expedient embodiments and developments of the invention are set forth in the dependent claims as well as in the following description.

[0009] According to the document, the sensor is an ultrasonic sensor for a motor vehicle including a sensor housing and a pot-shaped membrane connected to the sensor housing, the membrane having a membrane bottom for transmitting and / or receiving ultrasonic signals and a membrane wall connected to the membrane bottom, a portion of the membrane wall extending into the sensor housing, and a first encapsulant material that fills the housing interior space is disposed within the housing segment on the side of the sensor housing facing the membrane bottom.

[0010] According to the invention, the first encapsulating material at least partially penetrates into the membrane inner space of the membrane surrounded by the membrane wall, while the membrane is geometrically connected to the sensor housing by the first encapsulating material.

[0011] The membrane is thereby adhered to the sensor housing by the first encapsulant and fixed relative to the sensor housing, i.e., the first encapsulant here assumes the role of forming a corresponding geometric fixation in addition to the role of sealing and mechanically separating the membrane from the sensor housing.

[0012] Therefore, the configuration according to the present invention has an advantage in that it can provide an improved configuration of an ultrasonic sensor with a simplified structure and assembly.

[0013] To allow the membrane wall to extend into the sensor housing, the outer diameter of the membrane wall is smaller than the inner diameter of the sensor housing.

[0014] Advantageously, the membrane is integral with the membrane base and membrane wall, and is preferably made of aluminium.

[0015] In a preferred embodiment, the positive coupling is at least axially and circumferentially active, i.e., the positive coupling is performed at least in the axial and circumferential directions.

[0016] In a further preferred embodiment, a gap is formed in the housing interior space between the outer side of the membrane wall extending into the sensor housing and the inner side of the housing wall of the housing segment, and the first encapsulant at least partially extends into the gap. The first encapsulant is supported by the outer side of the membrane wall and the inner side of the housing wall. Preferably, the first encapsulant completely extends into the gap, i.e., completely fills the gap. This contributes to a reliable geometrical connection in this region, at least in the circumferential direction.

[0017] In a further preferred embodiment, the axial end of the membrane wall facing away from the membrane bottom is provided with a ring-shaped projection extending outward in the circumferential direction around the axial end of the membrane wall, particularly preferably around the entire circumference, which allows for a particularly favorable geometric connection, the projection here preferably extending outward in the circumferential direction perpendicular to the membrane wall.

[0018] In a further preferred embodiment, the first encapsulation material has a notch in it that corresponds to the protrusion (11) of the membrane wall, the protrusion being located in the notch and thus acting geometrically at least in the axial and circumferential directions, so that the first encapsulation material here has a notch that corresponds to and receives the surrounding protrusion, but in the assembled state the first filling material completely surrounds the protrusion.

[0019] In a further preferred embodiment, a ring-shaped flexible molding is arranged in the axial segment of the gap on the side facing the bottom side of the membrane, the protrusion resting on the molding and the positive connection acting in the axial direction, i.e., the positive connection acting via the first encapsulating material and the flexible molding.

[0020] In a further preferred embodiment, the first encapsulant extends circumferentially within the housing interior space to the inside of the housing wall of the housing segment, while the first encapsulant extends circumferentially within the membrane interior space to the inside of the membrane wall.

[0021] In a further preferred embodiment, the first encapsulation material extends circumferentially within the membrane interior space, preferably completely filling the membrane interior space, and not only forms a geometric bond but also, particularly preferably, serves as a damping agent for the membrane interior bottom and / or membrane wall.

[0022] In a further preferred embodiment, the first encapsulant is integrally formed from a first material, which is advantageously made from an elastomer, a thermoplastic, a thermoset, or a silicone material.

[0023] In a further preferred embodiment, the first encapsulation material extends axially in the membrane interior space only along one segment of the membrane wall facing away from the membrane bottom, while a second encapsulation material is arranged in direct contact with the first encapsulation material and extends axially from the first encapsulation material to the inside of the membrane bottom and circumferentially to the inside of the membrane wall in the membrane interior space, advantageously made of a first material and the second encapsulation material made of a second material different from the first material, particularly preferably performing a vibration damping role in the membrane bottom and / or in the region of the membrane wall facing the membrane bottom. [Brief explanation of the drawings]

[0024] The present invention will now be described in more detail with reference to the accompanying drawings, in which: [Figure 1a] The ultrasonic sensor is shown in a three-dimensional exploded view. [Figure 1b] The ultrasonic sensor according to FIG. 1a is shown in cross section. [Figure 2a] 1 is an exploded view of an ultrasonic sensor according to an alternative embodiment; [Figure 2b] The ultrasonic sensor according to FIG. 2a is shown in cross section. [Figure 3a] An ultrasonic sensor according to a further alternative embodiment is shown in exploded view as follows: [Figure 3b] The ultrasonic sensor according to FIG. 3a is shown in cross section. [Figure 4a] An ultrasonic sensor according to a further alternative embodiment is shown in exploded view as follows: [Figure 4b] The ultrasonic sensor according to FIG. 4a is shown in cross section. [Figure 5a] Further alternative embodiments of ultrasonic sensors are shown in exploded views and [Figure 5b] 5a shows the ultrasonic sensor according to FIG. 5a in cross section. DETAILED DESCRIPTION OF THE INVENTION

[0025] Corresponding parts are always labeled with the same reference numerals in all figures.

[0026] 1a and 1b show an embodiment of an ultrasonic sensor 1 from different angles. In Fig. 1a, the ultrasonic sensor 1 is shown in an exploded view, and in Fig. 1b, it is shown in a cross-sectional view.

[0027] The ultrasonic sensor 1 includes an integral sensor housing 2 with a plurality of connection pins 3 and a wiring board 4 disposed within the sensor housing 2 and connected to the connection pins 3. The ultrasonic sensor 1 also includes a pot-shaped membrane 5 connected to the sensor housing 2, the membrane 5 having a membrane bottom 6 for transmitting and / or receiving ultrasonic signals and a membrane wall 7 connected to the membrane bottom 6, with a portion of the membrane wall 7 extending into the sensor housing 2. A disk-shaped piezo ceramic is disposed inside the membrane bottom 6 and electrically connected to the wiring board 4. At the axial end of the sensor housing 4 opposite the membrane 5, the sensor housing 2 is closed by a cover 8.

[0028] A first encapsulant 10 is arranged in the housing interior space of the housing segment 9 on the side of the sensor housing 2 facing the membrane bottom 6, completely filling this housing interior space, and is formed integrally from a first material, particularly preferably an elastomer, thermoplastic, thermosetting or silicone material.

[0029] The first encapsulation material 10 extends in the circumferential direction R in the housing interior space of the sensor housing 2 up to the inside of the housing wall of the housing segment 9 of the sensor housing 2. In so doing, the first encapsulation material 10 completely fills the gap formed between the outside of the membrane wall 7 extending into the sensor housing 2 and the inside of the housing wall of the housing segment 9.

[0030] In addition, the first encapsulation material 10 extends into the internal space of the membrane 5 surrounded by the membrane wall 7, and the first encapsulation material 10 extends to the inside of the membrane wall 7 in the circumferential direction R and to the inside of the membrane bottom 6 in the axial direction Z. That is, the first encapsulation material 10 completely fills the internal space of the membrane and plays a role in damping the membrane bottom 6 and the membrane wall 7.

[0031] Furthermore, at the axial end of the membrane wall 7 opposite the membrane bottom 6, a ring-shaped protrusion 11 is provided, which is perpendicular to the membrane wall 7 and extends circumferentially outward, surrounding the entire periphery of the axial end of the membrane wall 7, and is located within the first encapsulating material 10 and engages with a notch corresponding to the protrusion 11, and the first encapsulating material 10 is configured to completely surround the protrusion 11.

[0032] The shape and arrangement of the first encapsulating material 10 as a whole ensures a reliable geometrical connection between the sensor housing 2 and the membrane 5, and between the membrane 5, and in particular its protrusions 11, in the axial direction Z and the circumferential direction R. In other words, the first encapsulating material 10 not only provides a sealing function, vibration damping between the membrane bottom 6 and the membrane wall 7, and mechanical isolation between the membrane 5 and the sensor housing 2, but also the formation of an appropriate geometrical connection and therefore a reliable fixation of the membrane 5 to the sensor housing 2.

[0033] Figures 2a and 2b show different angles of an alternative embodiment of the ultrasonic sensor 1. In Figure 2a, the ultrasonic sensor 1 is shown in an exploded view, and in Figure 2b, it is shown in a cross-sectional view.

[0034] This ultrasonic sensor 1 is essentially similar to the ultrasonic sensor 1 shown in FIGS. 1 a to 1 b, but here the ultrasonic sensor 1 also comprises a second encapsulant 12 in addition to the first encapsulant 10 .

[0035] In this case, the first encapsulation material 10 extends in the axial direction Z in the membrane interior space only along one segment of the membrane wall 7 facing away from the membrane bottom 6, while a second encapsulation material 12 is arranged in direct contact with the first encapsulation material 10. The second encapsulation material 12 extends in the axial direction Z in the membrane interior space from the first encapsulation material 10 to the inside of the membrane bottom 6 and in the circumferential direction R to the inside of the membrane wall 7. The second encapsulation material 12 is made of a second material different from the first material of the first encapsulation material 10. Here, the second encapsulation material 12 plays a role of vibration damping in particular in the region of the membrane bottom 6 and of the membrane wall 7 facing the membrane bottom 6. In this case, a material that is particularly suitable for vibration damping purposes can be used as the second material.

[0036] Figures 3a and 3b show a further alternative embodiment of the ultrasonic sensor 1 from different angles. In Figure 3a, the ultrasonic sensor 1 is shown in an exploded view, and in Figure 3b, it is shown in a cross-sectional view.

[0037] This ultrasonic sensor 1 is essentially similar to the ultrasonic sensor 1 shown in FIGS. 1a to 1b, but here, in addition to the first encapsulant 10, the ultrasonic sensor 1 also comprises a ring-shaped flexible molded body 13.

[0038] The flexible shaped body 13 is arranged in the gap between the outside of the membrane wall 7, which extends into the sensor housing 2, and the inside of the housing wall of the housing segment 9 of the sensor housing 2, in the axial region on the side facing the membrane bottom 6. In this case, the protrusions 11 formed on the membrane wall 7 come into contact with the shaped body 13 and act as a positive connection in the axial direction Z. In short, the positive connection here acts via the first encapsulation material 10 and the flexible shaped body 13.

[0039] Figures 4a and 4b show a further alternative embodiment of the ultrasonic sensor 1 from different angles. In Figure 4a, the ultrasonic sensor 1 is shown in an exploded view, and in Figure 4b, it is shown in a cross-sectional view.

[0040] This ultrasonic sensor 1 is essentially similar to the ultrasonic sensor 1 shown in FIGS. 2a to 2b, but here, in addition to the first encapsulant 10, the ultrasonic sensor 1 also comprises a ring-shaped flexible molded body 13.

[0041] The flexible shaped body 13 itself is then arranged in the axial region facing the membrane bottom 6 between the outside of the membrane wall 7 recessed into the sensor housing 2 and the inside of the housing wall of the housing segment 9 of the sensor housing 2, while the protrusions 11 formed on the membrane wall 7 rest on the shaped body 13, so that a positive connection acts in the axial direction Z. In short, here, a positive connection acts in particular via the first encapsulation material 10 and the flexible shaped body 13.

[0042] Figures 5a and 5b show a further alternative embodiment of the ultrasonic sensor 1 from different angles. In Figure 5a, the ultrasonic sensor 1 is shown in an exploded view, and in Figure 5b, it is shown in a cross-sectional view.

[0043] The ultrasonic sensor 1 is essentially similar to the ultrasonic sensor 1 shown in Figures 1a to 1b, but here the sensor housing 2 is formed as a hollow cylinder in the axial end region facing the membrane bottom 6, and in this axial end region a front cap 14 is connected to the sensor housing 2 by means of a snap connection.

[0044] It will be apparent to those skilled in the art that such an arrangement with a similar sensor housing 2 and a similar front cap 14 can also be used for the embodiments of Figures 2a to 4b. [Explanation of symbols]

[0045] 1 ultrasonic sensor 2 Sensor Housing 3 connecting pins 4. Wiring board 5. Membrane 6 membrane bottom 7. Membrane Wall 8 Cover 9 Housing segments of the sensor housing 10 First Enclosure 11 Protrusion 12 Secondary Encapsulating Material 13 Molded body 14 Front cap R circumferential direction Z axis direction

Claims

1. 1. An ultrasonic sensor for a motor vehicle comprising a sensor housing (2), a membrane bottom (6) connected to the sensor housing (2) for transmitting and / or receiving ultrasonic signals, and a pan-shaped membrane (5) having a membrane wall (7) connected to the membrane bottom (6), with a portion of the membrane wall (7) extending into the sensor housing (2), and a first filling material (10) is arranged in a housing interior space of a housing segment (9) facing the membrane bottom (6) of the sensor housing (2) and filling the housing interior space, The ultrasonic sensor (1) is characterized in that the first encapsulating material (10) at least partially penetrates into an internal space of a membrane (5) surrounded by a membrane wall (7), and the membrane (5) is shape-connected to a sensor housing (2) by the first encapsulating material (10).

2. 2. Ultrasonic sensor (1) according to claim 1, characterized in that the positive connection acts in at least one axial direction (Z) and in at least one circumferential direction (R).

3. 3. The ultrasonic sensor (1) according to claim 1 or 2, characterized in that a gap is formed in the housing interior space between the outside of the membrane wall (7) extending into the sensor housing (2) and the inside of the housing wall of the housing segment (9), and the first encapsulant (10) at least partially extends into the gap.

4. 10. An ultrasonic sensor (1) according to claim 9, characterized in that at the axial end of the membrane wall (7) opposite the membrane bottom (6), a ring-band-like projection (11) is provided which surrounds the axial end of the membrane wall (7) and extends outward in the circumferential direction.

5. 5. The ultrasonic sensor (1) according to claim 4, characterized in that in the first encapsulation material (10) a notch is provided which corresponds to the protrusion (11) of the membrane wall (7) and the protrusion (11) is arranged in the notch, thereby acting geometrically at least in the axial and circumferential directions (Z, R).

6. 5. The ultrasonic sensor (1) according to claim 2, characterized in that in the axial segment of the gap on the side facing the membrane bottom (6), a ring-shaped flexible molding (13) is arranged, the projection (11) rests on the molding (13) and its positive joint acts in the axial direction (Z).

7. An ultrasonic sensor (1) according to any one of the preceding claims, characterized in that the first encapsulation material (10) extends in the circumferential direction (R) within the housing interior space up to the inside of the housing wall of the housing segment (9) and that the first encapsulation material (10) extends in the circumferential direction (R) within the membrane interior space up to the inside of the membrane wall (7).

8. 10. An ultrasonic sensor (1) according to any one of the preceding claims, characterized in that the first encapsulation material (10) extends in the axial direction (Z) within the membrane inner space up to the inside of the membrane bottom (6).

9. 10. The ultrasonic sensor arrangement (1) according to any one of the preceding claims, characterized in that the first encapsulant (10) is integrally formed from a first material.

10. 9. The ultrasonic sensor (1) according to claim 1, characterized in that the first encapsulation material (10) extends in the axial direction (Z) in the membrane inner space only along one segment of the membrane wall (7) facing away from the membrane bottom (6), but a second encapsulation material (12) is arranged in direct contact with the first encapsulation material (10) and extends in the membrane inner space from the first encapsulation material (10) in the axial direction (Z) to the inside of the membrane bottom (6) and in the circumferential direction (R) to the inside of the membrane wall (7).

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