Ultrasonic transducer

Abstract

The invention relates to an ultrasound transducer having a container (2) with an opening, a base (3) opposite the opening, and a side wall (4) connecting the base (3) to the opening, an axial direction (A) being directed from the opening to the base (3), the side wall (4) having a first region (24) in which the base (3) is located in a first region (24), the side wall (4) is directly connected to the bottom (3) in a direction opposite the axial direction (A), and wherein the side wall (4) has a second region (25) which is connected to the first region (24) in a direction opposite the axial direction (A) and up to the opening; a sound transducer (9), wherein the sound transducer (9) is arranged on the bottom (3) inside the container (2); and a mounting holder (14) which is connected to the first region (24) of the side wall (4), the mounting holder (14) being separated from the entire second region (25) of the side wall (4) by an air gap (26).

Description

Technical Field

[0001] The present invention relates to an ultrasonic transducer. Background Art

[0002] Ultrasonic transducers are generally used for distance measurement. During the transmission operation, when measuring distance, the ultrasonic transducer emits an ultrasonic signal as a short pulse train, and part of the ultrasonic signal is reflected back after hitting an object. During the reception operation, the reflected pulse is detected, and thus the transit time can be obtained. Since ultrasonic waves propagate in air and also in water at a known speed of sound, the distance to the reflecting object can be calculated by means of the transit time.

[0003] Automobiles, for example, use ultrasonic distance measurement in parking assistance systems, and the distance measurement transmits an alarm signal to the driver when the distance to a nearby object is small. Ultrasonic transducers are usually installed in the bumper, which provides relatively more space for installing the ultrasonic transducer together with the housing and the required electronic devices. The development and application of new technologies, such as drones, vacuum robots, lawn mowing robots, and general autonomous robots, pose new challenges to ultrasonic transducers suitable for distance measurement.

[0004] WO 2020 / 245 064A2 shows an ultrasonic transducer having a container with an opening, a bottom, and a wall.

[0005] DE 10 2020 132 631A1 shows an ultrasonic sensor having a housing in which a diaphragm assembly is provided, and the plastic housing is fastened at the open end of the housing via a decoupling element. Other ultrasonic sensors are known from DE 10 2012 200639A1 and DE 10 2016 221 535A1, in which the diaphragm cans are respectively connected to the housing at their open ends.

[0006] In the ultrasonic sensors known in the prior art, separately manufactured and inserted elastic damping elements are respectively used between the open ends of the diaphragm cans and the sensor housing. Here, the diaphragm cans are in complete contact with the decoupling elements in a large area in the axial and radial directions. This particularly causes a significant attenuation of the vibration of the diaphragm cans in the area near the opening of the diaphragm cans. Therefore, it is common to implement the area of the diaphragm cans as solidly as possible in order to minimize the interference effect.

[0007] JP 2003-315 443A shows an ultrasonic transducer having a can-shaped inner housing and an outer housing. DE 102021 104 697A1 shows an ultrasonic transducer in which the electronic device is integrated in the lid of the can-shaped transducer. Summary of the Invention

[0008] The object of the present invention is now to describe an improved ultrasonic transducer. For example, an ultrasonic transducer should be described in which the vibration of the diaphragm can is attenuated as little as possible by its mounting. For example, an ultrasonic transducer should be described in which the diaphragm can dispense with a mounting flange at its open end without thereby causing a significant disturbance of the vibration of the diaphragm can.

[0009] The object is achieved by an ultrasonic transducer according to claim 1.

[0010] The present invention provides an ultrasonic transducer having a container with an opening, a bottom opposite the opening, and a side wall connecting the bottom to the opening. The axial direction is defined as the direction from the opening towards the bottom. The side wall has a first region and a second region. The side wall can consist of the first region and the second region.

[0011] In the first region, the side wall is directly connected to the bottom in a direction opposite to the axial direction. The second region is connected to the first region in a direction opposite to the axial direction and extends up to the opening. Furthermore, the ultrasonic transducer has a sound transducer, wherein the sound transducer is arranged on the bottom inside the container. The ultrasonic transducer has mounting holding means connected to the first region of the side wall, wherein the mounting holding means is separated from the entire second region of the side wall by an air gap.

[0012] The container can be can-shaped. The container can be held by the mounting holding means at its closed end. The open end of the container can be separated from the mounting holding means by an air gap and can accordingly vibrate freely. During operation of the ultrasonic transducer, a vibration antinode is formed at the open end of the container. The first region of the side wall includes the closed end to which the mounting holding means is connected. The second region of the side wall includes the open end.

[0013] In the second region, the side wall can vibrate with a large vibration amplitude. By the way in which the side wall can be designed to vibrate freely here, the vibration of the ultrasonic transducer is attenuated only minimally. A freely vibrating air-gap suspension results from the mounting holding means. Due to the small attenuation of the vibration of the ultrasonic transducer, the signal-to-noise ratio can be improved when the ultrasonic transducer is used as a sensor.

[0014] The opening of the container can be closed by a lid.

[0015] The container can be made of plastic, for example fiber-reinforced plastic, or of aluminum, for example. The container can have a plurality of cylindrical sections with different radii.

[0016] The first region can correspond to the section with the smallest radius. Alternatively, the first region can be a partial region of a cylindrical section.

[0017] The sound transducer can be a piezoelectric element, such as a piezoelectric disk. The piezoelectric disk can be integral, with electrodes formed on the upper and lower sides of the disk respectively.

[0018] The mounting and holding device can be a sleeve-shaped element that surrounds the container and is in mechanical contact with the container only in a first region of the side wall. The ultrasonic transducer can be installed in the outer housing of the target application via the mounting and holding device. The outer housing cannot be in direct contact with the container here. Here, the mounting and holding device can be designed such that the outer housing and the container are decoupled from each other with respect to solid-borne sound vibrations, that is, the solid-borne sound vibrations of the outer housing are not transmitted to the container or are transmitted to the container only to a very small extent.

[0019] The second region extending up to the opening of the container can have a constant wall thickness of the side wall. Correspondingly, the side wall can have no mounting flange at its open end region.

[0020] When installed in a target object, such as a vehicle or a robot, the outer housing separate from the mounting sleeve can be dispensed with. A simple, inexpensive, durable, and compact system can be constructed.

[0021] The mounting and holding device can be indirectly connected to the side wall in the first region. In particular, the mounting and holding device can be connected to the side wall via a decoupling element in the first region, where the decoupling element radially surrounds the side wall in the first region. The decoupling element can be designed such that it transmits vibrations from the side wall to the mounting and holding device only to a very small extent and in the opposite direction.

[0022] The decoupling element can be elastic, and its hardness is, for example, less than 60 Shore A hardness, preferably less than 30 Shore A hardness, and especially less than 20 Shore A hardness. The decoupling element can have a hardened polymer, such as silicone resin. Due to the low hardness of the decoupling element, the decoupling element additionally contributes to particularly good decoupling of the vibrations between the mounting and holding device and the container.

[0023] The ultrasonic transducer can have a Belleville spring, which is arranged between the decoupling element and the air gap. The Belleville spring can seal the air gap relative to the decoupling element. The decoupling element can be manufactured, for example, by a casting method in which a liquid material is filled into the region between the mounting and holding device and the side wall. Here, the Belleville spring can prevent the liquid material from entering the air gap.

[0024] The ultrasonic transducer can be designed such that when the sound transducer excites ultrasonic vibrations at the bottom, vibration nodes are formed in the first region of the side wall. Since the mounting and holding device is only connected to the first region where the vibration nodes are formed, this connection only causes a very small attenuation of the vibrations.

[0025] The ultrasonic transducer may have a cover that closes the container, where an electronic device may be integrated in the cover, and where the electronic device is in electrical contact with the sound transducer and is designed to control and read the sound transducer. Thus, a printed circuit board separate from the ultrasonic transducer for manipulating the ultrasonic transducer can be dispensed with. Such a separate printed circuit board would require additional shielding means. Since, instead, the electronic device can be mounted in the cover of the ultrasonic transducer, additional components can be dispensed with, and the ultrasonic transducer can be constructed more durably and more compactly.

[0026] Alternatively, the cover can be formed by a mounting retaining means or by a sheath that is mechanically connected to the mounting retaining means and that surrounds the end of the mounting retaining means pointing away from the bottom.

[0027] An air gap can at least partially cover the back side of the cover pointing away from the sound transducer. The air gap can correspondingly extend along a second region of the side wall and along the back side of the cover. In this region, the container can vibrate freely and its vibration will not be impeded by the mounting.

[0028] An interface can be provided on the back side of the cover pointing away from the sound transducer, and the interface can be sealed by means of the sheath. The interface can be a digital input interface and an output interface. The interface can have a connection plug. The sheath can protect the interface from external influences such as dust and water. The sheath can be mechanically connected to the mounting retaining means.

[0029] The ultrasonic transducer can have a stop safety device that is provided on the side of the side wall pointing away from the bottom, where a gap is formed between the stop safety device and the side wall in the stationary state of the ultrasonic transducer, and where the stop safety device delimits a section in which the side wall can move in the axial direction. Correspondingly, the stop safety device can ensure protection against damage caused by excessive movement of the container.

[0030] The mounting retaining means can have a radially outwardly pointing protrusion against which a sealing ring abuts. The mounting retaining means can have a thread on the outer side pointing away from the container, and the mounting retaining means has a nut that is screwed onto the thread. The ultrasonic transducer can be connectable to a housing such that the sealing ring is placed on the upper side of the housing and presses the nut against the lower side of the housing. Here, the sealing ring can be compressed and the connection can be sealed.

[0031] In another embodiment, the mounting retaining means can have a recess on the outer side pointing away from the container, and the recess is configured for latching with a latching hook respectively. The ultrasonic transducer can be connected to the housing such that the sealing ring is placed on the upper side of the housing, and a latching hook is provided at the lower side of the housing, and the latching hook latches with the recess. Here, the sealing ring can be compressed and the connection can be sealed.

[0032] In another embodiment, the ultrasonic transducer may be connectable to the housing such that the sealing ring abuts against the lower side of the housing and the upper side of the housing is flush with the bottom, wherein at the lower side there are provided snap hooks which press the mounting holding device against the lower side of the housing. Here, the sealing ring may be squeezed and the connection may be sealed.

[0033] On the other hand, a module is concerned which has two of the above ultrasonic transducers which are arranged in a common module housing. The module housing may here form the mounting holding devices for the two ultrasonic transducers. The two mounting holding devices may be integrally formed by the module housing. One of the ultrasonic transducers may be designed to operate as a transmitter and the other ultrasonic transducer may be designed to operate as a receiver.

[0034] The module housing forming the two mounting holding devices enables the two ultrasonic transducers to be arranged very close to each other. This can also be achieved in such a way that wide mounting flanges can be dispensed with, since the respective containers of the ultrasonic transducers are held at the front, closed end.

[0035] By using two transducers, one of which serves as a transmitter and the other as a receiver, it is possible to detect an object at a very short distance from the module. Description of the Drawings

[0036] Preferred embodiments will be described in detail below with reference to the drawings.

[0037] Figure 1 The ultrasonic transducer is shown in a schematic view.

[0038] Figure 2 The insertion of the ultrasonic transducer into the housing is shown schematically.

[0039] Figure 3 The ultrasonic transducer according to the second embodiment is shown, which is mounted in the housing of the target application.

[0040] Figure 4 An alternative embodiment is shown, in which the ultrasonic transducer is inserted into the housing from the lower side.

[0041] Figure 5 The ultrasonic transducer with an envelope is shown, which seals the rear side of the container facing away from the bottom.

[0042] Figure 6 The module with two ultrasonic transducers is shown.

[0043] Figure 7 The module housing is shown in a perspective view. Detailed implementation mode

[0044] Figure 1 The ultrasonic transducer 1 is shown. The ultrasonic transducer has a pot-shaped container 2, which has an opening, a bottom 3 and a side wall 4. The axial direction A is defined as the direction from the bottom 3 towards the opening. The container 2 can be made of a conductive material, such as aluminum, or a conductive plastic or a conductively coated plastic, or can be made of a non-conductive material, such as plastic, especially fiber-reinforced plastic. Hereinafter, the direction pointing to the bottom 3 is always referred to as "in front in the axial direction". The direction pointing to the opening is always referred to as "behind in the axial direction".

[0045] The side wall 4 is constructed of two cylindrical parts, namely a front part 5 and a rear part 6. The front part 5 has a smaller radius than the rear part 6 and is closed at a circular base surface by the bottom 3, which also serves as a diaphragm. The front part is open towards the rear in the axial direction A. The entire container 2 is one-piece, and the rear part 6 is connected to the front part 5 via a connecting surface 7 extending parallel to the bottom 3. The rear part is also open at its rear end in the axial direction A. The opening of the container is closed by a lid 8.

[0046] Inside the container 2, a sound transducer 9, such as a piezoelectric disk, is arranged on the bottom 3. The sound transducer 9 is fixed to the bottom 3 by means of an adhesive layer or an adhesive disk. Furthermore, a damping element 10 is provided, which is matched to the shape of the container 2 and completely fills the container. Via a metal wire 11 or a contact part on the inner side of the container 2, the sound transducer 9 is connected to an electronic device 12. The electronic device is arranged on the inwardly facing side of the lid 8. The lid 8 itself is a printed circuit board. The lid 8 has an interface 13, such as a digital I / O interface, on its outwardly facing side. The interface 13 has a connection plug.

[0047] Via the interface 13, not only outward communication is realized, but also power is supplied to the electronic device 12 and the sound transducer 9. The arrangement of the interface 13 on the lid 8 enables a compact structural form and simple contact of the ultrasonic transducer 1, because no other connection parts need to be taken into account.

[0048] Furthermore, the ultrasonic transducer 1 has a mounting and holding device 14. The mounting and holding device 14 is a sleeve-shaped element that surrounds the container 2. In front in the axial direction A, the front end of the mounting and holding device 14 is arranged in the same plane as the bottom 3 of the container 2. In the rear in the axial direction A, the mounting and holding device 14 projects beyond the container 2.

[0049] The mounting and holding device 14 has an inwardly protruding projection 15 and an outwardly protruding projection 16 at its front end in the axial direction. Due to the two projections 15, 16, the wall thickness of the mounting and holding device 14 at its front end is greater than the wall thickness in the remaining area of the mounting and holding device.

[0050] In the Figure 1 embodiment shown, the inwardly protruding projection 15 is flush with the rear part 6 of the side wall 4 in the axial direction. In an alternative embodiment, the inwardly protruding projection 15 may overlap with the rear part 6. In another alternative embodiment, the inwardly protruding projection 15 may be designed to be short such that it does not overlap with the rear part 6.

[0051] In the remaining area, the mounting and holding device 14 has a sleeve shape, and the diameter of the sleeve shape is smaller than the maximum diameter of the outwardly protruding projection 16. On the outer side 17 facing away from the container, the mounting and holding device has a thread 18 and / or a recess 19 for latching the latching hook 33. In the Figure 1 embodiment shown, the mounting and holding device 14 has a thread 18 and a recess 19. In an alternative embodiment, the mounting and holding device may only have one of the thread 18 and the recess 19.

[0052] The inner side 21 of the mounting and holding device 14 facing the container is configured as a flat wall in the area where the side wall 4 is sleeve-shaped.

[0053] The surface of the outwardly protruding projection 16 formed at the rear in the axial direction A forms a stop surface 22. When installing the ultrasonic transducer 1, the sealing ring 30 can abut against the stop surface 22.

[0054] The mounting and holding device 14 is connected to the side wall 4 of the container 2. The side wall 4 is divided into a first area 24 and a second area 25. The side wall 4 may be constructed from the first area 24 and the second area 25.

[0055] Here, the first area 24 is the area where the side wall 4 is connected to the mounting and holding device 14. In particular, the inwardly protruding projection 15 of the mounting and holding device 14 is connected to the side wall 4.

[0056] The second area 25 is the area where the side wall 4 is not connected to the mounting and holding device 14 but is separated from the mounting and holding device by an air gap 26. The inner side 21 of the mounting and holding device 14 is separated from the side wall 4 by the air gap 26 in the second area 25. The air gap 26 ensures the decoupling of structure-borne sound between the second area 25 of the side wall 4 and the mounting and holding device 14.

[0057] The first region 24 of the side wall 4 is the region in which the side wall 4 is directly connected to the bottom 3 in a direction opposite to the axial direction A. When the sound transducer 9 is excited to vibrate and thereby the container 2 is put into vibration, a vibration node is formed in the first region 24. The second region 25 of the side wall 4 is the region including the end of the side wall 4 facing away from the bottom 3. When the sound transducer 9 is excited to vibrate and thereby the container 2 is put into vibration, a vibration antinode is formed in the second region 25.

[0058] Fastening the mounting holding device 14 in the first region 24 ensures that the vibration of the container 2 is attenuated only minimally by the mounting holding device 14, since the mounting holding device 14 is connected at the position of the vibration node and is separated from the position of the vibration antinode by the air gap 26. In contrast, if the mounting holding device 14 is connected to the side wall 4 in the region of the vibration belly, the mounting holding device 14 will strongly interfere with the vibration of the container 2.

[0059] The structure-borne sound generated in the container 2 is transmitted to the mounting holding device 14 only to a small extent through the connection of the mounting holding device 14 to the first region 24 of the side wall 4. If the mounting holding device 14 is mounted in the outer housing of the target application, conversely, the structure-borne sound generated in the target application is transmitted to the container 2 of the ultrasonic transducer 1 only to a very small extent. The mounting holding device 14 can thus achieve a structure-borne sound decoupled mounting of the vibratable components of the ultrasonic transducer 1.

[0060] The container 2 vibrates essentially freely relative to the mounting holding device 14. Thus, a free-vibration air-gap suspension results. The movement of the free-vibration air-gap suspension is limited by the decoupling element 27 described hereinafter and the stop insurance device 28 described hereinafter.

[0061] The target application can for example be the bumper of a vehicle or the front part of a robot, such as a harvesting robot.

[0062] In Figure 1 the illustrated embodiment, the first region 24 of the side wall 4 corresponds to the front part 5 of the side wall 4, in which the side wall 4 has a smaller radius than in the rear part 6. In an alternative embodiment, the side wall 4 can be connected only to a partial region of the front part 5. Thus, in the alternative embodiment, the first region 24 can be designed smaller and include only a part of the front part 5.

[0063] The mounting and holding device 14 is connected to the container 2 indirectly via a decoupling element 27 in the first region 24. The decoupling element 27 is annular. The decoupling element 27 annularly surrounds the first region 24 of the side wall 4. The decoupling element 27 abuts at the inner side 21 of the mounting and holding device 14. In particular, the decoupling element 27 abuts at the inwardly protruding projection 15 of the mounting and holding device 14. The decoupling element 27 is adhesively bonded to the mounting and holding device 14 and the side wall 4 and thereby connects the mounting and holding device 14 and the side wall 4.

[0064] The decoupling element 27 has an elastic material. The decoupling element 27 can have a hardened polymer, such as silicone or silicone elastomer.

[0065] The hardness of the decoupling element 27 can be less than 60 Shore A hardness. The decoupling element 27 is produced by a casting method in which a liquid material is filled into the gap between the mounting and holding device 14 and the container 2. The liquid material hardens and forms the decoupling element 27. By this method, it is feasible to precisely set the decoupling element 27 with such a low hardness. Alternatively, the decoupling element 27 can be manufactured or installed by joining techniques or other manufacturing methods.

[0066] Due to the low hardness of the decoupling element 27, the decoupling element allows relative movement with a small amplitude of movement of the mounting and holding device 14 and the container 2 relative to each other. The decoupling element 27 delimits the section in which the container 2 can move forward relative to the mounting and holding device 14 in the radial direction and in the axial direction.

[0067] The ultrasonic transducer 1 has a disc spring 29 which is arranged between the decoupling element 27 and the air gap 26. The disc spring 29 ensures that in the casting method, the liquid material does not enter the air gap 26. The disc spring 29 seals the air gap 26 relative to the decoupling element 27.

[0068] Furthermore, the ultrasonic transducer 1 has a stop safety device 28 which is arranged axially behind the container 2 and is separated from the container 2 by the air gap 26 in the rest state of the ultrasonic transducer 1. Here, the state in which no external force is applied to the container 2 is called the rest state.

[0069] The stop safety device 28 ensures that the section in which the container 2 can move backward in the axial direction A is delimited. Thereby, it can be ensured that the force applied to the container 2 in the axial direction A does not cause damage to the ultrasonic transducer 1.

[0070] Figure 2 The insertion of the ultrasonic transducer 1 according to the first embodiment into the external housing 32 of the target application is shown in a schematic view.

[0071] The ultrasonic transducer 1 has a sealing ring 30 which abuts against the stop face 22 of the outwardly projecting projection 16 of the mounting and holding device 14. The sealing ring 30 is an O-ring. The sealing ring 30 is made of an elastic material. By means of the sealing ring 30, a simple and at the same time reliable sealing against dust and water can be achieved, which meets the requirements of the IP rating. The sealing ring 30 forms a simple compression seal without the need for additional components.

[0072] The mounting and holding device 14 has a thread 18 on its outer side 17. The ultrasonic transducer 1 has a nut 31 which is screwed into the thread 18 on the outer side 17 of the mounting and holding device 14.

[0073] A free area is formed between the sealing ring 30 and the nut 31. If the ultrasonic transducer 1 is now inserted into the housing 32 of the target application, the housing 32 can be arranged in this free area. Here, the sealing ring 30 is placed on the upper side of the housing 32, and the nut 31 presses against the housing 32 from below, so that the sealing ring 30 is compressed by the housing 32 and thus sealed.

[0074] Figure 3 The ultrasonic transducer 1 according to the second embodiment is shown, which is inserted into the housing 32 of the target application. Different from the first embodiment, the outer side 17 of the mounting and holding device 14 does not have a thread 18. The mounting and holding device 14 has a plurality of cutouts 19 which are designed to be latched with the latching hooks 33 of the housing 32.

[0075] The housing 32 has corresponding latching hooks 33 at its lower side. If the ultrasonic transducer 1 is inserted into the housing 32, the sealing ring 30 is placed on the upper side of the housing 32. The latching hooks 33 on the lower side of the housing 32 are latched with the cutouts 19 of the mounting and holding device 14. By means of the outwardly projecting projection 16 of the mounting and holding device 14 and the housing 32, the sealing ring 30 is pressed and the connection is sealed. The mounting and holding device 14 can have, for example, three cutouts 19. The mounting and holding device 14 can have any other number of cutouts 19. The housing 32 has the same number of latching hooks 33 as the number of cutouts 19 of the mounting and holding device 14.

[0076] In Figure 2 and Figure 3 In the embodiments shown, the ultrasonic transducer 1 is inserted into the upper side of the housing 32 and clamped from below either by screwing on the nut 31 or by latching the latching hooks 33. Figure 4 An alternative embodiment is shown, in which the ultrasonic transducer 1 is inserted into the housing 32 from below.

[0077] The mounting and retaining device 14 has an outwardly protruding projection 16 which is formed in the middle region of the mounting and retaining device 14 in the axial direction. The sealing ring 30 is axially located on the front side of the outwardly protruding projection 16. If the ultrasonic transducer 1 is mounted in the housing 32, the sealing ring 30 is squeezed between the lower side of the housing 32 and the front side of the outwardly protruding projection 16. Additionally, a snap hook 34 is formed at the lower side of the housing 32, which can be connected to the lower side of the container 2 and press the container 2 towards the lower side of the housing 32. The bottom 3 of the container 2 and the upper side of the housing 32 can be arranged flush with each other.

[0078] In Figures 2 to 4 the shown mounting variant, when the ultrasonic transducer 1 is mounted in the housing 32, the housing separate from the mounting and retaining device 14 can be dispensed with. Instead, the ultrasonic transducer 1 can be directly mounted to the target object via the mounting and retaining device 14. Since the electronic device 17 for control is also mounted in the ultrasonic transducer 1 itself, any additional components can be dispensed with. In this way, a simple, inexpensive, durable and compact overall system can be constructed.

[0079] Figure 5 An ultrasonic transducer 1 with a jacket 35 is shown, which seals the rear side of the container 2 facing away from the bottom 3. The jacket 35 can be a protection device against dirt, dust and water. A cable guide 36 can be formed in the jacket 35, via which the interface 13 can be accessed. The jacket 35 can be directly connected to the nut 31. In Figure 5 the shown jacket 35 can be combined with each of the embodiments shown above. In embodiments without the nut 31, the jacket 35 can be directly connected to the mounting and retaining device 14.

[0080] Figure 6 A module with two ultrasonic transducers 1 is shown. The two ultrasonic transducers 1 are arranged in a common module housing 37. The module housing 37 hereby forms two mounting and retaining devices 14 for the ultrasonic transducers 1. The two mounting and retaining devices 14 are thus formed integrally. In an alternative design of the module, more than two ultrasonic transducers 1 can be arranged in the common module housing 37.

[0081] Connecting the mounting and retaining device 14 to the container 2 via the decoupling element 27 and forming the plurality of mounting and retaining devices 14 integrally by the module housing 37 enables a compact construction of the module. Thereby, two or more ultrasonic transducers 1 can be arranged very close to each other spatially.

[0082] One of the two ultrasonic transducers 1 can be used as an ultrasonic transmitter, and the other ultrasonic transducer of the two ultrasonic transducers 1 can be used as an ultrasonic receiver. Such a module can also detect objects at very small distances. This would not be possible if only the sole ultrasonic transducer 1 were used as both transmitter and receiver, because after transmission, the diaphragm must first be allowed to vibrate subsequently before the ultrasonic transducer 1 can be used to detect reflections.

[0083] Figure 7 The module housing 37 is shown in a perspective view.

[0084] List of reference numerals

[0085] 1 Ultrasonic transducer

[0086] 2 Container

[0087] 3 Bottom

[0088] 4 Side wall

[0089] 5 Front part

[0090] 6 Rear part

[0091] 7 Connection surface

[0092] 8 Cover

[0093] 9 Sound transducer

[0094] 10 Attenuation element

[0095] 11 Metal wire

[0096] 12 Electronic device

[0097] 13 Interface

[0098] 14 Mounting retention device

[0099] 15 Inwardly projecting protrusion

[0100] 16 Outwardly projecting protrusion

[0101] 17 Outer side

[0102] 18 Thread

[0103] 19 Cut-out

[0104] 21 Inner side

[0105] 22 Stop surface

[0106] 24 First region

[0107] 25 Second region

[0108] 26 Air gap

[0109] 27 Decoupling element

[0110] 28 Stop safety device

[0111] 29 Belleville spring

[0112] 30 Sealing ring

[0113] 31 Nut

[0114] 32 Housing

[0115] 33 Latching hook

[0116] 34 Buckle hook

[0117] 35 Sheath

[0118] 36 Cable guide

[0119] 37 Module housing

[0120] A Axial direction

Claims

1. An ultrasonic transducer (1), the ultrasonic transducer having: - A container (2), the container having an opening, a bottom (3) opposite the opening, and a side wall (4) connecting the bottom (3) to the opening, wherein an axial direction (A) points from the opening towards the bottom (3), wherein the side wall (4) has a first region (24) in which the side wall (4) is directly connected to the bottom (3) in a direction opposite to the axial direction (A), wherein the side wall (4) has a second region (25) which is connected to the first region (24) in a direction opposite to the axial direction (A) and extends up to the opening, - A sound transducer (9), wherein the sound transducer (9) is arranged on the bottom (3) within the container (2), and - Mounting and holding means (14), the mounting and holding means being connected to the first region (24) of the side wall (4), wherein the mounting and holding means (14) is separated from the entire second region (25) of the side wall (4) by an air gap (26).

2. The ultrasonic transducer (1) according to claim 1, wherein the mounting and holding means (14) is indirectly connected to the first region (24) of the side wall (4).

3. The ultrasonic transducer (1) according to claim 1 or claim 2, wherein the mounting and holding means (14) is connected to the first region (24) of the side wall (4) via a decoupling element (27), wherein the decoupling element (27) radially surrounds the side wall (4) in the first region (24).

4. The ultrasonic transducer (1) according to claim 3, wherein the decoupling element (27) is elastic.

5. The ultrasonic transducer (1) according to claim 3 or claim 4, wherein the hardness of the decoupling element (27) is less than 60 Shore A hardness.

6. The ultrasonic transducer (1) according to any one of claims 3 to 5, wherein the decoupling element (27) has a hardened polymer, such as silicone resin.

7. The ultrasonic transducer (1) according to any one of claims 3 to 6, wherein a disc spring (29) is provided between the decoupling element (27) and the air gap (26).

8. The ultrasonic transducer (1) according to any one of the preceding claims, wherein the container (2) vibrates freely in a second region (25) of the side wall (4).

9. The ultrasonic transducer (1) according to any one of the preceding claims, wherein the ultrasonic transducer (1) is designed such that when the sound transducer (9) excites ultrasonic vibrations of the bottom (3), a vibration node is formed in a first region (24) of the side wall (4).

10. The ultrasonic transducer (1) according to any one of the preceding claims, wherein the sound transducer (9) has a piezoelectric disk.

11. The ultrasonic transducer (1) according to any one of the preceding claims, wherein the ultrasonic transducer (1) has a cover (8) that closes the container (2), wherein electronic means (12) are integrated in the cover (8), and wherein the electronic means (12) are in electrical contact with the sound transducer (9) and are designed to control and read the sound transducer (9).

12. The ultrasonic transducer (1) according to claim 11, wherein the air gap (26) at least partially covers the back side of the cover (8) facing away from the sound transducer (9).

13. The ultrasonic transducer (1) according to claim 11 or claim 12, wherein an interface (13) is provided on the back side of the cover (8) facing away from the sound transducer (9), and wherein the back side of the cover (8) facing away from the sound transducer (9) is sealed by a sheath (35).

14. The ultrasonic transducer (1) according to any one of the preceding claims, wherein the ultrasonic transducer (1) has a stop safety device (28) that is provided on the side of the side wall (4) facing away from the bottom (3), wherein in the rest state of the ultrasonic transducer (1), a gap is formed between the stop safety device (28) and the side wall (4), and wherein the stop safety device (28) delimits the section in which the side wall (4) can move in the axial direction.

15. The ultrasonic transducer (1) according to any one of the preceding claims, wherein the mounting and holding device (14) has a radially outwardly directed projection (16) against which the sealing ring (30) abuts in the axial direction.

16. The ultrasonic transducer (1) according to any one of the preceding claims, wherein the mounting and holding device (14) has a thread (18) on the outer side (17) facing away from the container (2), wherein the mounting and holding device (14) has a nut (31) screwed onto the thread (18).

17. The ultrasonic transducer (1) according to claims 15 and 16, wherein the ultrasonic transducer (1) can be connected to a housing such that the sealing ring (30) is placed on the upper side of the housing and presses the nut (31) against the lower side of the housing.

18. The ultrasonic transducer (1) according to any one of claims 1 to 15, wherein the mounting and holding device (14) has a clearance (19) on the outer side (17) facing away from the container (2), and the clearance is configured for latching respectively with a latching hook (33).

19. The ultrasonic transducer (1) according to claims 15 and 18, wherein the ultrasonic transducer (1) can be connected to a housing (32) such that the sealing ring (30) is placed on the upper side of the housing (32), and a latching hook (33) is provided at the lower side of the housing (32), and the latching hook latches with the clearance (19).

20. The ultrasonic transducer (1) according to claim 15, wherein the ultrasonic transducer (1) can be connected to a housing (32) such that the sealing ring (30) abuts against the lower side of the housing (32), and the upper side of the housing (32) is flush with the bottom (3), wherein a snap hook (34) is provided at the lower side, and the snap hook presses the mounting and holding device (14) against the lower side of the housing (32).

21. A module having two ultrasonic transducers (1) according to any one of the preceding claims, and the ultrasonic transducers are arranged in a common module housing (37).

22. The module according to the previous claim, wherein the module housing (37) forms the mounting and holding device (14) for the two ultrasonic transducers (1).

23. The module according to claim 21 or claim 22, One of the ultrasonic transducers (1) is designed to operate as a transmitter, and the other ultrasonic transducer in the ultrasonic transducer (1) is designed to operate as a receiver.

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