Holder concept for providing a concealed ultrasonic sensor for measuring distances in a motor vehicle

Abstract

The invention relates to a holding device (16) comprising a receiving area (58) for an ultrasonic sensor (52) for measuring distances in motor vehicles. The holding device (16) together with the ultrasonic sensor (52) is concealed in a bumper (10) of the motor vehicle. The holding device (16) comprises a transmission element (20) which transmits, in the ultrasonic range, the movement generated by the ultrasonic sensor (52) to the material of the bumper (10), which serves as a membrane. The invention also relates to the use of the holding device (16) with an ultrasonic sensor (52) for measuring distances in motor vehicles.

Description

[0001] Robert Bosch GmbH RB24 / 2724PC

[0002] - 1 -

[0003] Description

[0004] title

[0005] Mounting device with a receptacle for an ultrasonic sensor for distance measurement in motor vehicles

[0006] Technical field

[0007] The invention relates to a holding device with a receptacle for an ultrasonic sensor for distance measurement in motor vehicles, wherein the holding device with the ultrasonic sensor is concealed within a bumper of the motor vehicle. Furthermore, the invention relates to the use of the holding device with an ultrasonic sensor for distance measurement in motor vehicles.

[0008] State of the art

[0009] Ultrasonic transducers for use in motor vehicles essentially comprise one or more membranes that are excited to vibrate in the ultrasonic range by piezoelectric elements. The membrane movement transmits its vibration into acoustic waves that propagate in the space in front of the transducer. The geometric design of the membrane, i.e., the dimensions of the vibrating surface, defines the field of view (FoV) in front of the sensor. Objects in the direction of sound propagation reflect the emitted sound waves. Upon striking the sensor membrane, the reflected sound waves cause a membrane movement that can be detected by the transducer as an electrical signal. By relating the time of emission to the time of detection of the reflected sound wave, the distance to objects can be determined using the speed of sound in air.Robert Bosch GmbH RB24 / 2724PC.

[0010] - 2 -

[0011] Typically, the ultrasonic transducers used in motor vehicles to measure the distance between the vehicle and obstacles or objects are individual sensor units integrated into the front or rear fairing, particularly the bumper. Installing multiple sensors creates a system that, through triangulation algorithms, enables precise localization of the position of objects and obstacles around the vehicle.

[0012] Depending on the described radiation pattern of the individual ultrasonic transducers, specifications arise regarding their placement and the number of transducers used in the vehicle to achieve the greatest possible coverage in front of and behind the vehicle. These installation specifications concerning the mounting height and orientation of the sensors in the vehicle are intended to ensure the detection of as many different objects and obstacles as possible, as well as the comparability of performance between different vehicles.

[0013] The sensor membrane is positioned in recesses in the bumper, and the sensor housing is secured by a bracket attached to the inside of the bumper. Flush mounting of the sensor membrane to the bumper surface ensures optimal sound radiation. To integrate the sensors as discreetly as possible into the bumper, the sensor surface or membrane may be painted to match the vehicle's color. A decoupling element, usually a silicone ring, between the sensor membrane and the bumper prevents the transmission of membrane vibrations to the bumper surface and thus to adjacent sensors. This transmission, also known as crosstalk, can affect the measurement signal of individual sensors and consequently cause objects or obstacles to be detected incorrectly or not at the correct distances from the vehicle.

[0014] The control of the transducers and the evaluation of the received ultrasonic signals are usually performed using an integrated circuit (ASIC). The abstracted results are transmitted to a central control unit (ECU), which combines the results from one or more transducers and processes them for further evaluation by the vehicle system. (In some cases, Robert Bosch GmbH RB24 / 2724PC)

[0015] - 3 -

[0016] Algorithms based on machine learning, neural networks, but also classical data analysis are used to classify the detected objects and derive recommendations for action for the driver of the vehicle.

[0017] Ultrasonic sensors for measuring the distance of the vehicle to obstacles or objects serve as the basis for the realization of automated driving or parking functions, such as an automated parking process.

[0018] In addition to the described ultrasonic sensor systems for distance measurement, the same sensors can be used for presence detection to protect vehicle components by detecting potential objects when concealed. In one design variant, the sensors are concealed within the vehicle doors. Due to the lack of a recess for the sensor diaphragm and the absence of a decoupling element, the diaphragm's vibrations are transmitted directly to the vehicle door, causing it to vibrate in the ultrasonic range when the sensor is active. The reflection from an object directly in front of the door then influences the door's vibration behavior, which can be detected by evaluating the ultrasonic transducer signal and thus stops the door from opening.Consequently, an exact measurement of the distance to the detected obstacle and a display of the distances for the customer in the central display based on this measurement, as well as the implementation of parking functions on this basis, is not possible.

[0019] In addition to this installation option, concepts exist for the concealed installation of ultrasonic sensors. According to US 2007 / 0062292 Al, the sensor is attached planarly to the bumper. In this approach, the bumper material is selectively thinned or geometrically structured (see also

[0020] DE 102012 207 160 Al and US 2020 / 0033473 Al). However, due to this local reduction in material, the position of the ultrasonic sensor behind the bumper remains visually perceptible.

[0021] Another approach to implementing a concealed ultrasonic sensor is described in US 2007 / 0115102 Al. This involves the geometry Robert Bosch GmbH RB24 / 2724PC.

[0022] - 4 -

[0023] a diaphragm pot adapted by placing a cylinder on the diaphragm pot to initiate the diaphragm movement into the bumper via a piston.

[0024] Disclosure of the invention

[0025] The ultrasonic sensors used today for distance measurement in vehicles are clearly visible due to their mounting technology and can influence or even detract from the overall aesthetics of a vehicle design. It is essential to determine an installation position that ensures both sufficient performance of the ultrasonic sensor or sensor system and is acceptable from a design perspective. Furthermore, the installation requires considerable effort. The recesses for the sensor membrane must be incorporated into the bumper and machined during production. The sensor holder must be manufactured and precisely bonded into the bumper before the sensor, including its decoupling ring, can be mounted and painted.

[0026] Currently available covert ultrasonic sensors only allow for the detection of an object's presence (for example, for door security). Measuring the distance to objects is not yet possible with this system.

[0027] According to the invention, a holding device with a receptacle for an ultrasonic sensor for distance measurement in motor vehicles is proposed, wherein the holding device with the ultrasonic sensor is concealed within a bumper of the motor vehicle. The holding device comprises a transmission element that transmits the movement in the ultrasonic range generated by the ultrasonic sensor to the bumper material, which serves as a membrane.

[0028] Advantageously, the solution proposed according to the invention, in contrast to solutions known in the prior art, avoids a local reduction in the material thickness of the bumper, thereby saving machining costs and, in particular, making the individual sensors visually imperceptible from the outside. Robert Bosch GmbH RB24 / 2724PC

[0029] - 5 -

[0030] In an advantageous embodiment of the holding device proposed according to the invention, the transmission element transfers the movement of the ultrasonic sensor in the ultrasonic range to the bumper material via a solid-state joint. This design of the holding device eliminates the need for additional decoupling elements, such as currently used silicone rings.

[0031] In an advantageous further development of the holding device proposed according to the invention, it is provided that the solid joint is designed as a material thinning in the material of the bumper outside the transmission element.

[0032] Furthermore, it is advantageously provided in the holding device proposed according to the invention that the holding device, the solid body joint and the transmission element itself are a single component.

[0033] In an advantageous further development of the holding device proposed according to the invention, it is further proposed to design the holding device with a flat side lying flat against an inside of the bumper, so that the use of the bumper material as a membrane is significantly improved.

[0034] Furthermore, the solution proposed according to the invention provides that the connection between the sensor membrane of the ultrasonic sensor and the transmission element can be force-fit, form-fit, or material-fit. This allows for the use of a wide variety of manufacturing technologies, thus providing a high degree of flexibility. Additionally, the solution proposed according to the invention provides that the connection between the holding device and an inner surface of the bumper can also be force-fit, form-fit, or material-fit, which likewise allows for degrees of freedom with regard to the manufacturing technologies and joining techniques used.

[0035] Furthermore, the solution proposed according to the invention provides that a sensor housing of the ultrasonic sensor is received in the holding device by a positive locking mechanism, in particular a snap-fit ​​connection. This allows a sensor to be easily removed from the holding device. Robert Bosch GmbH RB24 / 2724PC

[0036] - 6 -

[0037] replace without having to replace the retaining device itself, which is connected to the inside of the bumper.

[0038] In an advantageous further development of the holding device proposed according to the invention, it is further provided that a target frequency of the overall system can be set by appropriately designing the thickness and / or height of the transmission element. In the present case, the overall system comprises the sensor membrane of the ultrasonic sensor including the piezoceramic, the holding device, and the bumper of the motor vehicle.

[0039] The holding device proposed according to the invention further provides that a target frequency of the overall system can be adjusted across a width of the solid-state joint. In this context, the overall system comprises the sensor membrane of the ultrasonic sensor, including the piezoceramic, the holding device, and the vehicle's bumper.

[0040] Furthermore, it should be emphasized that the holding device proposed according to the invention comprises a transmission element which is piston-shaped and has an oval, rectangular or round geometry.

[0041] Furthermore, the holding device proposed according to the invention advantageously provides that the geometry of the transmission element can influence the sound propagation characteristics of the ultrasonic sensor.

[0042] Furthermore, the holding device proposed according to the invention is designed such that the transmission element rests on a contact side of a membrane pot, which comprises a piezoceramic on the side opposite the contact side.

[0043] The holding device proposed according to the invention is furthermore designed such that the piezoceramic is used for both transmitting and receiving ultrasound signals and is connected to an application-specific integrated circuit (ASIC). Robert Bosch GmbH RB24 / 2724PC

[0044] - 7 -

[0045] Furthermore, the invention relates to the use of the holding device with an ultrasonic sensor for distance measurement in motor vehicles.

[0046] Advantages of the invention

[0047] The solution proposed according to the invention presents a novel mounting concept that enables the integration of a standard ultrasonic sensor and the coupling of the membrane movement in the ultrasonic range into the bumper of the vehicle. This allows the bumper material itself to be used as the membrane. In contrast to solutions known from the prior art, this does not require any local reduction in the material thickness of the bumper, thus eliminating the need for additional processing of the bumper material and making the individual sensors virtually invisible from the outside. This significantly improves the external appearance of the vehicle.

[0048] Furthermore, the mounting device proposed according to the invention eliminates the need for the additional integration of a decoupling element in the form of a silicone ring, as is currently common practice. Likewise, it eliminates the need to prepare the bumper with cutouts and to paint the sensors or individual sensor groups before integration into the bumper. The geometry of the mounting device allows for influencing the directional characteristics of individual sensors and the resulting field of view of sensor groups at the front and rear of the vehicle. Compared to concealed ultrasonic sensors already on the market, the mounting device proposed according to the invention ensures that the sensors continue to accurately measure the distance to potential obstacles.

[0049] In the holding device proposed according to the invention, the solid joint and the transmission element constitute a single component. The target frequency of the overall system can be adjusted by appropriately dimensioning the thickness or height of the preferably piston-shaped transmission element and by appropriately dimensioning the width of the solid joint. (See Robert Bosch GmbH RB24 / 2724PC.)

[0050] - 8 -

[0051] The complete system includes the sensor membrane of the ultrasonic sensor along with piezoceramic, mounting device and bumper.

[0052] In the holder concept proposed according to the invention, an ultrasonic transducer can itself be of a conventional design and comprise a membrane that forms a housing end, on which a piezoceramic, preferably in disc form, is mounted and set into vibration. The piezoceramic is used for both transmitting and receiving ultrasonic signals. It is connected to an application-specific integrated circuit (ASIC) where the received ultrasonic signals are evaluated.

[0053] Brief description of the drawings

[0054] Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

[0055] They show:

[0056] Figure 1 shows an embodiment of the holding device proposed according to the invention for realizing a concealed ultrasensor for distance measurement in motor vehicles,

[0057] Figure 2 shows a visualization of a membrane vibration and a resulting first sound propagation characteristic and

[0058] Figure 3 shows a visualization of a membrane vibration and a resulting second sound propagation characteristic for a transmission element geometry that differs from that in Figure 2.

[0059] Embodiments of the invention

[0060] In the following description of embodiments of the invention, identical or similar elements are designated by the same reference numerals, and repeated descriptions of these elements are omitted in individual cases. The figures represent the subject matter of the invention only schematically. Robert Bosch GmbH RB24 / 2724PC

[0061] - 9 -

[0062] The illustration in Figure 1 shows an embodiment of the holding device 16 proposed according to the invention for realizing a concealed ultrasonic sensor 52 for distance measurement in motor vehicles.

[0063] As can be seen from the schematic representation in Figure 1, a bumper 10 of a motor vehicle (not shown in detail here), preferably made of a plastic material, has an outer surface 12 and an inner surface 14. A retaining device 16 rests against the said inner surface 14 in planar contact along its flat side 18. The retaining device 16 shown here is, for example, a component injection-molded from plastic material, which is circular or rotationally shaped and rests against the bumper 10 with its flat side 18.

[0064] As further shown in the sectional view of Figure 1, the holding device 16 proposed according to the invention has a transmission element 20 which is integrated into the holding device 16 by means of a solid-state joint 22. The transmission element 22 is preferably piston-shaped in the form of a piston part 32. The solid-state joint 22 of the holding device 16 is represented by a material taper 26 in the plastic material of the holding device 16. A target frequency of the overall system can be set by means of a width 24 that the solid-state joint 22 has – in the form of said material taper 26. In the present context, the overall system comprises the sensor membrane 50 of the ultrasonic sensor 52 including piezoceramic 76, the holding device 16, and the bumper 10.

[0065] As can be further seen from the sectional view in Figure 1, the holding device 10, the aforementioned solid-body joint 22, and the transmission element 20, preferably piston-shaped, form a single component. The target frequency of the overall system can be adjusted via the thickness 36 of the transmission element 20, which is preferably piston-shaped, its height 38, and the aforementioned width 24 of the solid-body joint 22.

[0066] As can be further seen from the sectional view in Figure 1, a contact surface 42 of the piston-shaped transmission element 20 rests flat against a sensor membrane 50 of a membrane pot 44. The membrane pot 44 Robert Bosch GmbH RB24 / 2724PC

[0067] - 10 -

[0068] The device defines an interior space 46 and has on its side facing the interior space 46 a disc-shaped piezoceramic 76 in the form of a bulk piezo disk. This disk serves for both transmitting and receiving ultrasound signals and is connected to an application-specific integrated circuit (ASIC) not shown in detail here. The received ultrasound signals are evaluated in the application-specific integrated circuit (ASIC).

[0069] Reference numeral 40 denotes a geometry of the transmission element 20, which can assume an elliptical shape 68 (see Figure 2) or a round shape 70 (see Figure 3).

[0070] The sectional view in Figure 1 further shows that the holding device 16 proposed according to the invention has a receptacle 58 in the illustrated embodiment. A sensor housing 54 of the ultrasonic sensor 52 is inserted into said receptacle 58. The ultrasonic sensor 52 is a conventionally designed ultrasonic transducer comprising a sensor membrane 50, which forms the end of the sensor housing 54. In the present case, the sensor membrane 50 can advantageously be formed by the base of the membrane housing 44. Accordingly, the base of the membrane housing 44, which serves as the sensor membrane 50, is designed to be thin.

[0071] A sensor connector 56 extends laterally from the sensor housing 54 shown in Figure 1, via which the ultrasonic sensor 52 is connected to the wiring harness of the motor vehicle by means of a cable harness and a plug connection which is not shown in detail here.

[0072] As further shown in Figure 1, the holding device 16 comprises a fastening 60. The fastening 60 can, for example, be designed as a latch 62, as indicated in Figure 1. In this case, laterally extending latching lugs 66 are formed on the sensor housing 54 of the ultrasonic sensor 52, which engage in openings 64 in the area of ​​the receptacle 58 of the holding device 16. This enables a particularly simple replacement of a defective ultrasonic sensor 52 from the holding device 16 proposed according to the invention. This is preferably connected to the inner side 14 of the Robert Bosch GmbH RB24 / 2724PC

[0073] - 11 -

[0074] The ultrasonic sensor 52 is bonded to the bumper 10 and remains attached to the bumper 10. The ultrasonic sensor 52 can be easily removed and replaced by a new one by opening the form-fitting fastening 60, without having to remove the retaining device 16 which is preferably bonded to the inside 14 of the bumper 10.

[0075] Both the connection of the holding device 16 and the connection of the sensor membrane 50 to the transmission element 20 can be force-fit, form-fit, or material-fit. The described connection can, for example, be a connection between the sensor membrane 50, i.e., the pot base 44 of the ultrasonic sensor 52 serving as the membrane, and the transmission element 20, as can the connection of the holding device 16 to the inner surface 14 of the bumper 10. The aforementioned connections can each be force-fit, for example, by means of clamping; form-fit, for example, by means of a latching mechanism; or material-fit, for example, by means of a material-fit joining process such as welding. This allows for the use of a variety of joining and assembly techniques, thus providing a high degree of manufacturing flexibility.

[0076] Depending on the geometry 40 of the piston-shaped transmission element 20, whether elliptical 68 or round 70, the directional characteristic of the ultrasonic sensor 52, concealed behind the bumper 10, can be set independently of the directional characteristic of the original ultrasonic sensor. This allows for a wider range of placement options for the ultrasonic sensors 52 on the inside 14 of the bumper 10. The bumper 10 can be either the one mounted at the front of the vehicle or the one located at the rear of the vehicle.

[0077] The schematic representation in Figure 2 shows that, in this embodiment, the geometry 40 of the piston-shaped transmission element 20 has, for example, the aforementioned elliptical shape 68. Based on the ellipse, a first sound propagation characteristic 72 results, which also has a complementary elliptical appearance. Robert Bosch GmbH RB24 / 2724PC

[0078] - 12 -

[0079] In contrast to the representation in Figure 2, the representation in Figure 3 shows that the piston-shaped transmission element 20 has a round shape 70. Consequently, a second sound propagation characteristic 74 results, which is characterized by an annular extension around the contour of the round shape 70 of the piston-shaped transmission element 20.

[0080] The various geometries 40 of the piston-shaped transmission element 20 shown in Figures 2 and 3 advantageously allow the directional characteristic of the concealed ultrasonic sensor 52 to be influenced independently of the directional characteristic of the original ultrasonic sensor, thus providing further possibilities regarding the placement of the ultrasonic sensors on the inside 14 of the bumper 10. Since the thickness 36 or height 38 and the width 24 of the solid joint 22 provide further degrees of freedom for adjusting the target frequency of the overall system, a multitude of possible installation variants for ultrasonic sensors 52 are possible. These sensors are accommodated in the holding device 16 proposed according to the invention, as shown schematically in Figure 1.

[0081] The holding device 16 on the ultrasonic sensor 52 mounted in the area of ​​the receptacle 58 proposed in the invention is a standard ultrasonic sensor, the membrane movement of which in the ultrasonic range is coupled into the material of the bumper 10 via the contact of the flat side 18 of the holding device 16 with the inner side 14.

[0082] Furthermore, the invention relates to the use of the holding device 16 with an ultrasonic sensor 52 integrated in the receptacle 58 for distance measurement in motor vehicles.

[0083] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, within the scope specified by the claims, a multitude of modifications are possible that fall within the bounds of what is considered skilled in the art.

Claims

Robert Bosch GmbH RB24 / 2724PC - 13 - Claims 1. Holding device (16) with a receptacle (58) for an ultrasonic sensor (52) for distance measurement in motor vehicles, wherein the holding device (16) with the ultrasonic sensor (52) is concealed in a bumper (10) of the motor vehicle, characterized in that the holding device (16) comprises a transmission element (20) which transmits the movement generated by the ultrasonic sensor (52) in the ultrasonic range to the material of the bumper (10), which serves as a membrane.

2. Holding device (16) according to claim 1, characterized in that the transmission element (20) transmits the movement of the ultrasonic sensor (52) in the ultrasonic range via a solid body joint (22) to the material of the bumper (10).

3. Holding device (16) according to claims 1 and 2, characterized in that the solid body joint (22) is formed as a material reduction (26) in the material of the holding device (16) outside the transmission element (20).

4. Holding device (16) according to claims 1 to 3, characterized in that the holding device (16), the solid body joint (22) and the transmission element (20) are one component.

5. Holding device (16) according to claims 1 to 4, characterized in that the holding device (16) has a flat side (18) that rests flatly against an inner side (14) of the bumper (10).

6. Holding device (16) according to claims 1 to 5, characterized in that the connection between a sensor membrane (50) of the ultrasonic sensor (52) and the transmission element (20) is force-fit, form-fit or material-fit. Robert Bosch GmbH RB24 / 2724PC - 14 - 7. Holding device (16) according to claims 1 to 5, characterized in that the connection between an inner side (14) of the bumper (10) and a flat side (18) of the holding device (16) is force-fit, form-fit or material-fit.

8. Holding device (16) according to claims 1 to 5, characterized in that a sensor housing (54) of the ultrasonic sensor (52) is received in the holding device (16) by a positive locking fastening (60), in particular by means of a latching mechanism (62).

9. Holding device (16) according to claims 1 to 8, characterized in that a target frequency of the overall system can be set by a thickness (36) and / or a height (38) of the transmission element (20).

10. Holding device (16) according to claims 1 to 8, characterized in that a target frequency of the overall system can be set over a width (24) of the solid body joint (22).

11. Holding device (16) according to claims 1 to 10, characterized in that the transmission element (20) is piston-shaped and is elliptical, rectangular or in a round geometry (40).

12. Holding device (16) according to claims 1 to 11, characterized in that the geometry (40) of the transmission element (20) can influence the sound propagation characteristics (72, 74) of the ultrasonic sensor (52).

13. Holding device (16) according to claims 1 to 12, characterized in that the transmission element (20) rests against a contact side (42) of a membrane pot (44) which comprises a piezoceramic (76) on the side opposite the contact side (42).

14. Use of the holding device (16) according to claims 1 to 13 with an ultrasonic sensor (52) for distance measurement in motor vehicles.

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