Ultrasonic sensor for a motor vehicle with a sensor housing with a membrane and with a position holder for holding the membrane in the sensor housing and motor vehicle

Abstract

Ultrasonic sensor (5a) for a motor vehicle (1), with a sensor housing (11) and with a separate pot-shaped membrane (13), which is arranged in the sensor housing (11) and extends partially out of the sensor housing (11) through an opening (14) in the sensor housing (11), and with a position holder (15) which is separate from the sensor housing (11) and the membrane (13), with which the membrane (13) is held in position in the sensor housing (11) at least in the direction of a longitudinal axis (L) of the membrane (13), characterized in that the one-piece position holder (15) has a first holder part (16) which extends in the direction of the longitudinal axis (L) into the pot-shaped membrane (13).

Description

[0001] The invention relates to an ultrasonic sensor for a motor vehicle, comprising a sensor housing and a separate, pot-shaped membrane. The pot-shaped membrane is arranged in the sensor housing. The pot-shaped membrane extends partially out of the sensor housing through an opening in the sensor housing. The ultrasonic sensor further comprises a position holder, separate from the sensor housing and the membrane, with which the membrane is held in position in the sensor housing at least along a longitudinal axis of the membrane.

[0002] Ultrasonic sensors for motor vehicles are already known from the prior art and can be installed in the front and rear of a motor vehicle in a conventional manner. For example, the ultrasonic sensors can be arranged on the bumpers of the motor vehicle. The ultrasonic sensors can be assigned to a driver assistance system, for example, and provide information about the surroundings of the motor vehicle. For example, the ultrasonic sensors can be used to determine a distance between the motor vehicle and an object or obstacle in the surroundings of the motor vehicle. The driver assistance system can be designed, for example, as a parking assistance system, blind spot monitoring system, distance control system, brake assistance system, or the like.

[0003] Furthermore, it is already known for such ultrasonic sensors to be installed uncovered and thus visibly in associated trim parts, for example in bumpers. This means that they are arranged in corresponding through-openings in the associated trim part of the motor vehicle and are visible from the outside. Here, the membrane of the ultrasonic sensor, which can be cup-shaped, for example, extends through the through-opening of the trim part so that a front side of the membrane is flush with the outer surface of the trim part. Concealed ultrasonic sensors are also known. These are not visible when viewed from the outside and are covered by the trim part.With ultrasonic sensors installed in this way behind the trim part or the bumper, the ultrasonic signals are transmitted through the trim part and the ultrasonic signals reflected by an object are received through the trim part.

[0004] US 2015 / 0008796 A1 discloses an ultrasonic sensor. The ultrasonic sensor has an elastic fastening element with a pressing element, wherein a housing is held in a sensor housing by means of the fastening element.

[0005] A method for manufacturing an ultrasonic sensor is known from DE 10 2015 107 123 A1. A membrane for emitting an ultrasonic signal in a transmission direction and a sensor housing are provided, wherein the sensor housing has a front side facing in the transmission direction of the membrane and a rear side opposite the front side. The sensor housing is formed with a rear mounting opening, wherein the membrane is inserted into the sensor housing through the rear mounting opening in the transmission direction. In an interior of the sensor housing, the membrane is brought into a mounting position. The membrane is inserted into the interior of the sensor housing through the rear mounting opening and is positively connected to a fastening device and to the sensor housing by means of the fastening device. The membrane is held in the mounting position along the transmission direction.

[0006] The object of the present invention is to provide an ultrasonic sensor and a motor vehicle in which the positionally accurate mounting of the membrane in a sensor housing is improved.

[0007] This object is achieved by an ultrasonic sensor and a motor vehicle according to the independent claims.

[0008] One aspect of the invention relates to an ultrasonic sensor for a motor vehicle, comprising a sensor housing and a separate, pot-shaped membrane. The pot-shaped membrane is arranged in the sensor housing and, in the installed position, extends at least partially out of the sensor housing through a front opening in the sensor housing. The ultrasonic sensor has a position holder, separate from the sensor housing and the membrane, with which the membrane is held in position in the sensor housing at least in the direction of a longitudinal axis of the membrane. The longitudinal axis of the membrane is oriented, in particular, in the main beam direction of the ultrasonic signals of the ultrasonic sensor.

[0009] The one-piece position holder has a first holder part that extends into the cup-shaped membrane in the direction of the longitudinal axis. This design makes it possible for the position holder to extend at least partially within the cup-shaped membrane. This improves the precise positioning of the membrane in the sensor housing, particularly in the embodiments in focus, in which the membrane extends on both sides of an opening in the sensor housing. In particular, this design can also suppress disruptive shell vibrations of the cup-shaped membrane, since the first holder part can absorb and thus suppress these shell vibrations.In this way, sheath vibrations, which can occur both when transmitting the ultrasonic signal and when receiving an echo signal, can be suppressed, which also allows the ultrasonic sensor to operate more accurately with regard to object detection.

[0010] The ultrasonic sensor is designed in particular for visible or concealed installation in a continuous recess or through-opening of a trim part of the motor vehicle. The ultrasonic sensor has the membrane with which an ultrasonic signal can be emitted. For this purpose, the cup-shaped membrane can be excited to mechanical vibrations, for example, using a piezoelectric element, also called a piezo element, whereby this piezo element can be arranged at a base of the cup-shaped membrane. It is also possible for the membrane to receive ultrasonic signals that are reflected, for example, from an object. In this case, the membrane is excited to mechanical vibrations. These mechanical vibrations can then be detected by the piezo element. The ultrasonic sensor also has the sensor housing.The sensor housing allows the ultrasonic sensor to be mounted on the vehicle's body panel using a suitable bracket. The sensor housing primarily serves to house the ultrasonic sensor components.

[0011] In particular, the sensor housing has a rear mounting opening on its rear side viewed in the direction of the longitudinal axis, which is separate from the above-mentioned front opening. During manufacture of the ultrasonic sensor, the membrane can be inserted through this mounting opening towards the front opening. After the membrane has been inserted into the sensor housing, the membrane is in its mounting position. After the membrane has been inserted into the sensor housing, the position holder is inserted into the sensor housing via the rear mounting opening. The position holder serves in particular to hold the cup-shaped membrane in the mounting position. The position holder is in particular positively connected to the sensor housing. The sensor housing can have a substantially round cross-sectional area.The position holder can in particular be substantially cylindrical or tubular and arranged concentrically with the sensor housing.

[0012] In particular, the ultrasonic sensor enables simple and cost-effective production.

[0013] According to an advantageous embodiment, the first holder part can have a through-opening extending in the direction of the longitudinal axis. This makes it possible for additional components of the ultrasonic sensor to be introduced through this through-opening or for assembly tools to be passed through during manufacture of the ultrasonic sensor or during assembly of the ultrasonic sensor. For example, laser soldering can be enabled through the through-opening, so that in particular a piezo element of the ultrasonic sensor, which is located in the cup-shaped membrane, can be soldered to an electrical contact, particularly after assembly of the position holder. For example, solder can be applied to the piezo element before assembly of the ultrasonic sensor, so that contact can be made by laser soldering through the through-opening during assembly.In particular, it can be provided that the cup-shaped membrane, which is made of aluminum in particular, serves as a return conductor. This allows for reduced assembly effort for the ultrasonic sensor.

[0014] According to a further advantageous embodiment, the first holder part can be designed as a solid block. With the solid block design, the vibrations of the pot-shaped membrane, in particular the shell vibrations, can be reduced even more advantageously, allowing the ultrasonic sensor to operate even more reliably.

[0015] It is also advantageous if the first holder part extends axially on both sides of the front opening of the sensor housing. This allows the first holder part, in particular, to penetrate into the cup-shaped membrane and thus advantageously dampen the disruptive jacket vibrations, thus enabling improved operation of the ultrasonic sensor.

[0016] It has also proven advantageous if one end face of the first holder part rests on an integrally formed inner platform, which is formed on an inner wall of the cup-shaped membrane. In particular, this allows the membrane to be held even more advantageously in the mounting position. Furthermore, the support on the inner platform allows the position holder to more effectively absorb the shell vibrations, so that the shell vibrations in particular can be further dampened. This enables more reliable operation of the ultrasonic sensor. The axial positions of the components relative to one another can be achieved and maintained with particular precision using this inner platform.

[0017] According to a further embodiment, the position holder can have a second holder part, which has larger dimensions perpendicular to the longitudinal axis than the first holder part. In particular, the second holder part can then extend partially into an interior of the sensor housing. In particular, the position holder can then be attached to the sensor housing by means of the second holder part, so that the cup-shaped membrane is held in the mounting position. This allows a firm hold of the cup-shaped membrane in the sensor housing to be achieved.

[0018] The position holder is formed in one piece, in particular from plastic. The second holder part is arranged entirely within the sensor housing. In particular, the second holder part is arranged entirely outside the cup-shaped membrane.

[0019] It has also proven advantageous if the second holder part is designed in a trough-like manner. This allows the position holder to be manufactured with reduced material, since any free space in the trough is not filled with material. Furthermore, this allows the ultrasonic sensor to be reduced in weight.

[0020] According to a further advantageous embodiment, a side wall of the second holder part can be oriented parallel to the longitudinal axis at least in some regions in terms of its height (measured in the direction of the longitudinal axis), or the side wall of the second holder part can be oriented obliquely outwards, so that a funnel shape is formed. As a result, the position holder can be inserted with a precise fit onto an inner shape of the sensor housing, so that the position holder can reliably hold the membrane in the mounting position without the position holder slipping relative to the sensor housing perpendicular to the longitudinal axis of the sensor housing being possible. It is also advantageous if, in an alternative embodiment, a side wall of the second holder part is oriented obliquely outwards at least in some regions over its height, so that a funnel shape is formed.In particular, the position holder can be manufactured with less material, so that the overall weight of the position holder is reduced.

[0021] It has also proven advantageous if the second holder part rests directly on the diaphragm, in particular on a rear flange or rear collar of the diaphragm. In particular, the rear collar can limit the cup opening of the cup-shaped diaphragm. In particular, the collar is oriented perpendicular to the longitudinal axis and has larger dimensions than the opening of the sensor housing. In particular, this also forms a stop which limits movement in the direction of the longitudinal axis of the diaphragm relative to the sensor housing. In other words, when the diaphragm is in the mounting position, part of the diaphragm protrudes from the opening on the front of the sensor housing. Part of the diaphragm, which encompasses the collar, remains in the interior of the sensor housing.In particular, the collar can then be designed in such a way that the interaction of the collar with a sensor housing wall having the opening of the sensor housing limits the movement of the membrane in the transmission direction and improves the precise positional holding of the membrane.

[0022] It is also advantageous if the second holder part is detachably connected to the sensor housing in a non-destructive manner, in particular by being locked, so that an axial position of the position holder relative to the sensor housing is fixed. In particular, the membrane can then be pressed against a sensor housing wall that defines the opening in the sensor housing. This allows the membrane to be securely positioned on the sensor housing.

[0023] In particular, it can be provided that a locking element is arranged on the position holder and a receiving element corresponding to the locking element is provided on an inner side of the sensor housing, wherein the locking element can be positively connected to the receiving element. The locking element, which is arranged on the position holder, can be designed, for example, as a locking lug or elevation. A corresponding recess, which corresponds to the locking element, can be arranged on the inner side or inner surface of the sensor housing. In particular, a positive connection can thus be established between the position holder and the sensor housing. It can also be provided that the position holder has a plurality of locking elements which are arranged circumferentially along an outer surface of the position holder.In particular, the sensor housing or the interior of the sensor housing can also have corresponding receiving elements. This makes it possible, in particular, to ensure that the position holder is arranged in a positionally secure and / or rotationally secure manner relative to the sensor housing.

[0024] It is also possible for a hook element to be arranged on the position holder and for a support element corresponding to the hook element to be provided on the sensor housing, wherein in the mounted position the movement of the position holder in the longitudinal axis direction is limited by the connection of the hook element and the support element. A support surface can be formed, for example, by a corresponding surface of the sensor housing that is arranged in this region of the rear mounting opening. When the position holder is pushed into the sensor housing, the movement of the position holder in the longitudinal axis direction can be limited by the hook element coming into contact with the support element. This makes it easy to arrange the position holder in the correct position in the sensor housing.

[0025] According to a further advantageous embodiment, the position holder can also be designed as a decoupling element. In particular, the position holder is formed in one piece and is designed both materially and functionally as a decoupling element. In particular, the position holder is then made of a highly damping material. In particular, the additionally disruptive jacket vibrations of the diaphragm can thus be reliably suppressed by the position holder as a decoupling element. For example, the position holder can be made of polytetrafluoroethylene (PTFE), thereby dampening the jacket vibrations.

[0026] It has also proven advantageous to arrange an additional, separate decoupling element on a boundary edge defining the opening in the sensor housing. In particular, this additional, separate decoupling element prevents vibrations of the sensor housing, which occur, for example, during operation of the motor vehicle, from being transmitted to the cup-shaped membrane. Furthermore, the cup-shaped membrane can be dampened even more reliably from disruptive shell vibrations, allowing the ultrasonic sensor to operate more reliably overall.

[0027] According to a further advantageous embodiment, an electrical line for signal transmission to a piezo element of the ultrasonic sensor, which is arranged in the membrane, can be integrated into the position holder, and / or a separate damping element for the position holder and the membrane can be arranged between the first holder part and the piezo element of the ultrasonic sensor in the membrane.

[0028] In particular, the integration of the electrical line into the position holder enables simplified assembly of the ultrasonic sensor. For example, after the position holder has been inserted into the ultrasonic sensor during assembly, the electrical contact with the piezo element can be soldered using laser soldering, thus establishing an electrical connection with the piezo element. In particular, a silicone foam can be provided as the damping element. In particular, the dimensions of the damping element can enable the electrical line to be pressed onto the piezo element with sufficient force by the damping element.The position holder presses on the damping element, which in turn presses on the electrical line and the piezo element, thus establishing electrical contact between the electrical line and the piezo element. This not only establishes electrical contact between the electrical line and the piezo element, but also allows the pot-shaped membrane to be damped more reliably using the damping element, allowing the ultrasonic sensor to operate more reliably. By incorporating the damping element, soldering the electrical line to the piezo element is no longer necessary, since the electrical contact is established primarily through the pressure of the damping element on the electrical line in the mounted position.

[0029] It is also advantageous if an electrical contact of the ultrasonic sensor for electrically contacting the electrical line and the piezo element is pressed onto the piezo element by means of the position holder. This allows for automatic contact between the piezo element and the electrical line when the position holder is inserted into the sensor housing. Inserting the position holder into the sensor housing allows for contacting, damping, and securing the membrane. This allows for a reduced number of process steps in the ultrasonic sensor production.

[0030] Preferably, the position holder with the first and second holder part, the damping element and the electrical contact can be provided as a prefabricated part.

[0031] The invention further relates to a motor vehicle with at least one ultrasonic sensor. The motor vehicle is designed, in particular, as a passenger car. Advantageous embodiments of the ultrasonic sensor according to the invention are to be regarded as advantageous embodiments of the motor vehicle according to the invention.

[0032] Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or on their own without departing from the scope of the invention. Thus, embodiments are to be regarded as encompassed and disclosed by the invention that are not explicitly shown and explained in the figures, but which emerge from the separate combinations of features from the explained embodiments and can be generated. Embodiments and combinations of features are also to be regarded as disclosed which therefore do not have all the features of an originally formulated independent claim.Furthermore, embodiments and combinations of features, in particular those described above, are to be regarded as disclosed which go beyond or deviate from the combinations of features set out in the references to the claims.

[0033] Embodiments of the invention are explained in more detail below with reference to schematic drawings.

[0034] Showing: Fig. 1 a schematic plan view of an embodiment of a motor vehicle according to the invention with an embodiment of an ultrasonic sensor device according to the invention; Fig. 2 is a schematic cross-sectional view of an embodiment of an ultrasonic sensor; Fig. 3 shows a further schematic cross-sectional view of an embodiment of an ultrasonic sensor; and Fig. 4 a further schematic cross-sectional view of an embodiment of an ultrasonic sensor.

[0035] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0036] Fig. 1 shows a motor vehicle 1 according to an embodiment of the present invention. In the present exemplary embodiment, the motor vehicle 1 is embodied as a passenger car. The motor vehicle 1 comprises a driver assistance system 2. For example, the driver assistance system 2 can detect an object 3 located in the surroundings 4 of the motor vehicle 1. In particular, the distance between the motor vehicle 1 and the object 3 can be determined using the driver assistance system 2.

[0037] The driver assistance system 2 comprises at least one ultrasonic sensor device 5. The ultrasonic sensor device 5, in turn, has at least one ultrasonic sensor 5a. The ultrasonic sensor 5a comprises a transmitting device 6, by means of which at least one ultrasonic signal 8, in particular a plurality of ultrasonic signals 8, can be emitted. The ultrasonic sensor device 5 is presently arranged in a front region of the motor vehicle 1. The ultrasonic sensor device 5 can also be arranged in other regions, for example in a rear region or a side region of the motor vehicle 1. The following example should therefore not be considered exhaustive, but serves merely as an illustration.

[0038] With the transmitting device 6, the ultrasonic signals 8 can be emitted within a predetermined detection range E or a predetermined angular range by means of a membrane.

[0039] Furthermore, the ultrasonic sensor device 5 comprises a receiving device 7, by means of which reflected ultrasonic signals can be received as echo signals 9, which were reflected by the object 3, in particular via the membrane. The receiving device 7 can therefore receive ultrasonic signals 9 reflected by the object 3 as a received signal. Furthermore, the ultrasonic sensor device 5 can have a control device S, which can be formed, for example, by a microcontroller and / or a digital signal processor. The driver assistance system 2 further comprises a control device 10, which can be formed, for example, by an electronic control unit (ECU - electronic control unit) of the motor vehicle 1. The control device 10 is connected to the ultrasonic sensor device 5 for data transmission. The data transmission can take place, for example, via the data bus of the motor vehicle 1.

[0040] Fig. Figure 2 shows a schematic cross-sectional view of an embodiment of an ultrasonic sensor 5a. The ultrasonic sensor 5a has a sensor housing 11. The sensor housing 11 has an interior space 12. Furthermore, the ultrasonic sensor 5a has a separate pot-shaped membrane 13. The pot-shaped membrane 13 extends, in particular, at least partially through a front opening 14 of the sensor housing 11 in the direction of a longitudinal axis L. The ultrasonic sensor 5a has a one-piece position holder 15 that is separate from the sensor housing 11 and the pot-shaped membrane 13. The position holder 15 has a first holder part 16 and a second holder part 17. In particular, it is provided that the second holder part 17 of the position holder 15 has larger dimensions perpendicular to the longitudinal axis L of the ultrasonic sensor 5a than the first holder part 16. The longitudinal axis L is also the same as the longitudinal axis of the membrane 13 and the position holder 15.

[0041] In particular, it is provided that the position holder 15 is formed in one piece from plastic and the first holder part 16 extends in the direction of the longitudinal axis L into the cup-shaped membrane 13. In the direction of the longitudinal axis L, the membrane 13 and the first holder part 16 thus overlap. In particular, it can be provided that the first holder part 16 has a through-opening D extending in the direction of the longitudinal axis L. In particular, further processing of the ultrasonic sensor 5a can be realized by means of the through-opening D. For example, soldering of an electrical line 28 ( Fig. 3) with a piezo element 18 of the ultrasonic sensor 5a through the through-hole D when the position holder 15 is already arranged in its installation position in the sensor housing 11. This allows electrical contact with the piezo element 18 to be achieved after the position holder 15 has been inserted into the interior space 12 and after the cup-shaped membrane 13 has been fixed in the mounting position.

[0042] In particular, the first holder part 16 can have an end face 19 that rests on an inner platform 20 formed on an inner wall 21 of the cup-shaped membrane 13. In particular, this allows the cup-shaped membrane 13 to be securely held in position in a sensor housing 11.

[0043] Fig. Figure 2 further shows that the second holder part 17 is particularly trough-shaped. In particular, a side wall 22 of the second holder part 17 can be oriented obliquely outward, forming a funnel shape.

[0044] In particular, it is provided that the second holder part 17 rests directly against the cup-shaped membrane 13, in particular against a rear flange 23 of the cup-shaped membrane 13. In particular, the cup opening of the cup-shaped membrane 13 can be limited by means of the rear flange 23, which can also be referred to as a rear collar. In particular, the flange 23 has larger dimensions perpendicular to the longitudinal axis L than the opening 14. In other words, a movement of the cup-shaped membrane 13 in the direction of a transmission direction of the ultrasonic sensor 5a can thereby be limited.

[0045] In particular, the position of the cup-shaped membrane 13 can be held by means of receiving elements 24 on the sensor housing 11, in particular on an inner side 25 of the sensor housing 11. In particular, locking elements 26 corresponding to the receiving elements 24 can then be arranged on the second holder part 17. In particular, the second holder part 17 is then locked to the sensor housing 11, in particular to the locking elements 26, so that an axial position of the position holder 15 relative to the sensor housing 11 is also thereby fixed. In particular, this also makes it possible to press the cup-shaped membrane 13 against a sensor housing wall 30 having the opening 14 of the sensor housing 11.

[0046] In particular, it can be provided that the position holder 15 is also designed as a decoupling element. In particular, the position holder 15 can then be materially designed such that it can dampen shell vibrations of the cup-shaped membrane 13 that occur when transmitting ultrasonic signals 8 or receiving echo signals 9. This allows for reliable operation of the ultrasonic sensor 5a. In particular, the position holder 15 can be made of polytetrafluoroethylene (PTFE), for example, and thus realize the damping effect.

[0047] In particular, it is provided that an additional, separate decoupling element 27 is arranged on a boundary edge delimiting the opening 14 in the sensor housing 11. In particular, by means of the separate decoupling element 27, further shell vibrations of the cup-shaped membrane 13 or vibrations of the sensor housing 11, for example, during driving of the motor vehicle 1, can be reduced to the cup-shaped membrane 13. This enables more reliable operation of the ultrasonic sensor 5a.

[0048] In Fig. 2, the dashed line symbolizes the purely geometric separation between the first holder part 16 and the second holder part 17.

[0049] Fig. 3 shows a further cross-sectional view of an embodiment of an ultrasonic sensor 5a. Fig. 3 shows in particular that the first holder part 16 extends axially on both sides of the opening 14 of the sensor housing 11. In particular, the second holder part 17 has separate locking elements 26 which correspond to the receiving elements 24 of the sensor housing 11. In particular, the side wall 22 of the second holder part 17 in the present exemplary embodiment is oriented parallel to the longitudinal axis L over its entire height. In particular, the position holder 15 has an electrical line 18 which is integrated into the position holder 15. In particular, this allows signal transmission to the piezo element 18 to be realized. For example, the electrical line 28 can then be soldered to the piezo element 18 through the through-opening D.For example, a solder can be applied to the piezo element 18 before the ultrasonic sensor 5a is mounted, so that after the position holder 15 with the integrated electrical line 28 is inserted through the through-opening D by laser soldering, the electrical contact can be established via an electrical contact A with the electrical line 28.

[0050] Fig.4 shows a further cross-sectional view of an embodiment of an ultrasonic sensor 5a. In particular, the first holder part 16 is designed as a solid block here. In particular, in this embodiment, a damping element 29 can be arranged between the first holder part 16 and the piezo element 18. In particular, it is then provided that the damping element 29 establishes the electrical contact A between the electrical line 28 and the piezo element 18 through pressure of the position holder 15 on the damping element 29. In particular, this can prevent soldering of the electrical line 28 to the piezo element 18. The electrical contact A between the electrical line 28 and the piezo element 18 is then established solely through pressure of the damping element 29. In particular, a disruptive vibration of the piezo element 18 can be dampened by means of the damping element 29, so that the ultrasonic sensor 5a can be operated more reliably.In particular, it can be provided that the second electrical contact of the piezo element 18 is carried out via the cup-shaped membrane 13, which is made in particular of aluminum.

[0051] In particular, it is provided that electrical contact A of the ultrasonic sensor 5a is pressed against the piezo element 18 by means of the position holder 15 for electrically contacting the electrical line 28 and the piezo element 18. This allows automatic contact between the piezo element 18 and the electrical line 28 when the position holder 15 is inserted into the sensor housing 11. This allows contacting, damping, and fixing of the membrane 13 to be realized by inserting the position holder 15 into the sensor housing 11. This allows for a reduced number of process steps in the production of the ultrasonic sensor 5a.

[0052] Preferably, the position holder 15 with the first and second holder parts 16, 17, the damping element 29 and the electrical contact A can be provided as a prefabricated part.

Claims

[1] Ultrasonic sensor (5a) for a motor vehicle (1), comprising a sensor housing (11) and a separate pot-shaped membrane (13) which is arranged in the sensor housing (11) and extends partially out of the sensor housing (11) through an opening (14) in the sensor housing (11), and comprising a position holder (15) which is separate from the sensor housing (11) and the membrane (13) and with which the membrane (13) is held in position in the sensor housing (11) at least in the direction of a longitudinal axis (L) of the membrane (13), characterized by that the one-piece position holder (15) has a first holder part (16) which extends in the direction of the longitudinal axis (L) into the cup-shaped membrane (13). [2] Ultrasonic sensor (5a) according to claim 1, characterized by that the first holder part (16) has a through opening (D) extending in the direction of the longitudinal axis (L). [3] Ultrasonic sensor (5a) according to claim 1, characterized bythat the first holder part (16) is designed as a solid block. [4] Ultrasonic sensor (5a) according to one of the preceding claims, characterized by that the first holder part (16) extends axially on both sides of the opening (14) of the sensor housing (11). [5] Ultrasonic sensor (5a) according to one of the preceding claims, characterized by that an end face (19) of the first holder part (16) rests on an inner pedestal (20) which is formed on an inner wall (21) of the cup-shaped membrane (13). [6] Ultrasonic sensor (5a) according to one of the preceding claims, characterized by that the position holder (15) has a second holder part (17) which has larger dimensions perpendicular to the longitudinal axis (L) than the first holder part (16). [7] Ultrasonic sensor (5a) according to claim 6, characterized by that the second holder part (17) is trough-shaped. [8] Ultrasonic sensor (5a) according to claim 6 or 7, characterized bythat a side wall (22) of the second holder part (17) is oriented parallel to the longitudinal axis (L) or the side wall (22) of the second holder part (17) is oriented obliquely outwards, so that a funnel shape is formed. [9] Ultrasonic sensor (5a) according to one of claims 6 to 8, characterized by that the second holder part (17) lies directly on the membrane (13), in particular on a rear flange (23) of the membrane (13). [10] Ultrasonic sensor (5a) according to one of claims 6 to 9, characterized by that the second holder part (17) is locked to the sensor housing (11) so that an axial position of the position holder (15) relative to the sensor housing (11) is fixed. [11] Ultrasonic sensor (5a) according to one of the preceding claims, characterized by that the position holder (15) is also designed as a decoupling element. [12] Ultrasonic sensor (5a) according to one of the preceding claims, characterized bythat an additional separate decoupling element (27) is arranged on a boundary edge delimiting the opening (14) in the sensor housing (11). [13] Ultrasonic sensor (5a) according to one of the preceding claims, characterized by that an electrical line (28) for signal transmission to a piezo element (18) of the ultrasonic sensor (5a), which is arranged in the membrane (13), is integrated into the position holder (15), and / or a separate damping element (29) for the position holder (15) and the membrane (13) is arranged between the first holder part (16) and the piezo element (18) of the ultrasonic sensor (5a) in the membrane (13). [14] Ultrasonic sensor (5a) according to claim 13, characterized by that an electrical contact (A) of the ultrasonic sensor (5a) for electrically contacting the electrical line (28) and the piezo element (18) is pressed onto the piezo element (18) by means of the position holder (15). [15] Motor vehicle (1) with at least one ultrasonic sensor (5a) according to one of claims 1 to 14.

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