DE102022005131A1 - Ultrasonic transducer - Google Patents

Abstract

The present invention relates to an ultrasonic transducer which has a container (2) with an opening, a base (3) which is opposite the opening, and a side wall (4) which connects the base (3) to the opening, wherein an axial direction (A) points from the opening to the base (3), wherein the side wall (4) has a first region (24) in which the side wall (4) directly adjoins the base (3) in the direction opposite to the axial direction (A), wherein the side wall (4) has a second region (25) which adjoins the first region (24) in the direction opposite to the axial direction (A) and extends to the opening, a sound transducer (9), wherein the sound transducer (9) is arranged inside the container (2) on the base (3), and a mounting bracket (14) which is connected to the first region (24) of the side wall (4), wherein the mounting bracket (14) is surrounded by the entire second region (25) of the side wall (4) is separated by an air gap (26).

Description

The invention relates to an ultrasonic transducer.

Ultrasonic transducers are generally used to measure distances. In transmit mode, an ultrasonic signal is emitted as a burst from the ultrasonic transducer, which is partially reflected back after it hits an object. In receive mode, this reflected pulse is detected, which allows a travel time to be determined. Since the ultrasonic waves propagate in air and also in water at known sound speeds, the distance to the reflected object can be calculated using the travel time.

Vehicles use distance measurement using ultrasound, for example, in parking assistance systems that give the driver a warning signal when they are close to a nearby object. The ultrasonic transducers are usually housed in the bumpers, which offer a relatively large amount of space for installing an ultrasonic transducer, including a housing and the necessary electronics. New technological developments and applications, such as drones, robot vacuum cleaners, robot lawn mowers and autonomous robots in general, pose new challenges for an ultrasonic transducer suitable for distance measurement.

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

EN 10 2020 132 631 A1 shows an ultrasonic sensor with a housing in which a membrane assembly is arranged, wherein a plastic housing is attached to an open end of the housing via a decoupling element. From EN 10 2021 200 639 A1 and EN 10 2016 221 535 A1 Other ultrasonic sensors are known in which a membrane pot is connected to a housing at its open end.

In the ultrasonic sensors known in the state of the art, a separately manufactured and inserted elastic-damping element is used between an open end of a diaphragm cup and a sensor housing. The diaphragm cup is completely in contact with the decoupling element in large areas in the axial and radial direction. This leads to a significant damping of the vibration of the diaphragm cup, particularly in the areas located near the opening of the diaphragm cup. It is therefore common practice to make this area of the diaphragm cup as solid as possible in order to minimize the interference.

The object of the present invention is to provide an improved ultrasonic transducer. For example, an ultrasonic transducer is to be provided in which a vibration of the diaphragm pot is dampened as little as possible by its mounting. For example, an ultrasonic transducer is to be provided in which the diaphragm pot can dispense with a mounting collar at its open end without causing significant disturbances to the vibration of the diaphragm pot.

This object is achieved by an ultrasonic transducer according to claim 1.

An ultrasonic transducer is proposed which comprises a container with an opening, a bottom opposite the opening and a side wall connecting the bottom to the opening. An axial direction is defined as a direction from the opening to the bottom. The side wall comprises a first region and a second region. The side wall may consist of the first region and the second region.

In the first region, the side wall directly adjoins the base in the direction opposite to the axial direction. The second region adjoins the first region in the direction opposite to the axial direction and extends to the opening. The ultrasonic transducer further comprises a sound transducer, wherein the sound transducer is arranged on the base inside the container. The ultrasonic transducer comprises a mounting bracket which is connected to the first region of the side wall, wherein the mounting bracket is separated from the entire second region of the side wall by an air gap.

The container may be pot-shaped. The container may be held at its closed end by the mounting bracket. The open end of the container may be separated from the mounting bracket by an air gap and may accordingly be free-vibrating. An antinode is formed at the open end of the container when the ultrasonic transducer is operating. The first area of the side wall to which the mounting bracket is connected comprises the closed end. The second area of the side wall comprises the open end.

In the second area, the side wall can oscillate with a large oscillation amplitude. Because the side wall can be designed to swing freely, the Vibration of the ultrasonic transducer is only minimally dampened. The mounting bracket results in a freely swinging air gap suspension. Due to the low dampening of vibration of the ultrasonic transducer, the signal-to-noise ratio can be improved when the ultrasonic transducer is used as a sensor.

The opening of the container can be closed with a lid.

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

The first region may correspond to the section with the smallest radius. Alternatively, the first region may be a sub-region of a cylindrical section.

The sound transducer can be a piezoelectric element, for example a piezoelectric disk. The piezoelectric disk can be monolithic, with an electrode being formed on the top and bottom sides of the disk.

The mounting bracket can be a sleeve-shaped element that encloses the container and is only in mechanical contact with the container in the first area of the side wall. The ultrasonic transducer can be installed in an external housing of a target application via the mounting bracket. The external housing cannot be in direct contact with the container. The mounting bracket can be designed in such a way that the external housing and the container are decoupled from one another with regard to structure-borne sound vibrations, i.e. the structure-borne sound vibrations of the external housing are not transmitted to the container or are only transmitted to a very small extent.

The second region, which extends to the opening of the container, can have a constant wall thickness of the side wall. Accordingly, the side wall can be free of a mounting collar at its open end region.

A separate outer housing for the mounting sleeve can be dispensed with when mounting in a target object, such as a vehicle or a robot. A simple, inexpensive, resilient and compact system can be constructed.

The mounting bracket can be indirectly connected to the side wall in the first region. In particular, the mounting bracket can be connected to the side wall in the first region via a decoupling element, wherein the decoupling element radially encloses the side wall in the first region. The decoupling element can be designed in such a way that it only transmits vibrations from the side wall to the mounting bracket and in the opposite direction to a very small extent.

The decoupling element can be elastic and, for example, have a hardness of less than 60 Shore A, preferably less than 30 Shore A, in particular less than 20 Shore A. The decoupling element can comprise a cured polymer, for example silicone. Due to the low hardness of the decoupling element, this also contributes to the particularly good decoupling of vibrations between the mounting bracket and the container.

The ultrasonic transducer can have a disc spring that is arranged between the decoupling element and the air gap. The disc spring can seal the air gap against the decoupling element. The decoupling element can be manufactured, for example, in a casting process in which liquid material is poured into the area between the mounting bracket and the side wall. The disc spring can prevent the liquid material from penetrating the air gap.

The ultrasonic transducer can be designed in such a way that a vibration node forms in the first region of the side wall when the sound transducer excites an ultrasonic vibration of the floor. Since the mounting bracket is only connected to the first region in which the vibration node forms, this connection only leads to a very slight damping of the vibration.

The ultrasonic transducer can have a lid that closes the container, whereby electronics can be integrated in the lid, and whereby the electronics electrically contact the sound transducer and are designed to control and read the sound transducer. A separate circuit board for controlling the ultrasonic transducer can therefore be dispensed with. Such a separate circuit board would require additional shielding. Since the electronics can instead be installed in the lid of the ultrasonic transducer, additional components can be dispensed with and the ultrasonic transducer can be designed to be more resilient and compact.

Alternatively, the cover may be formed by the mounting bracket or by a casing that is mechanically connected to the mounting bracket and that encloses an end of the mounting bracket pointing away from the ground.

The air gap can at least partially cover a rear side of the lid facing away from the sound transducer. The air gap can accordingly extend along the second region of the side wall and along the rear side of the lid. In these regions, the container can be free-vibrating and its vibrations are not hindered by mounting.

An interface can be arranged on a rear side of the cover facing away from the sound transducer, which interface can be sealed with a casing. The interface can be a digital input and output interface. The interface can have a connector plug. The casing can protect the interface from external influences such as dust and water. The casing can be mechanically connected to the mounting bracket.

The ultrasonic transducer can have a stop lock arranged on the side of the side wall facing away from the bottom, wherein a gap is formed between the stop lock and the side wall in a rest state of the ultrasonic transducer, wherein the stop lock limits a distance in which the side wall can be moved in the axial direction. The stop lock can accordingly ensure that damage due to excessive movement of the container is prevented.

The mounting bracket can have a projection pointing outwards in a radial direction, against which a sealing ring rests. The mounting bracket can have a thread on an outer side pointing away from the container, wherein the mounting bracket has a nut screwed to the thread. The ultrasonic transducer can be connected to a housing in such a way that the sealing ring rests on an upper side of the housing and the nut presses against the underside of the housing. The sealing ring can be squeezed and the connection sealed.

In another embodiment, the mounting bracket can have recesses on an outer side facing away from the container, which are designed to lock with a locking hook each. The ultrasonic transducer can be connected to a housing in such a way that the sealing ring rests on an upper side of the housing and locking hooks are arranged on an underside of the housing, which lock with the recesses. The sealing ring can be squeezed and the connection sealed.

In a further embodiment, the ultrasonic transducer can be connected to a housing in such a way that the sealing ring rests on a bottom side of the housing and a top side of the housing is flush with the floor, with snap hooks arranged on the bottom side that press the mounting bracket against the bottom side of the housing. The sealing ring can be squeezed and the connection sealed.

A further aspect relates to a module that has two of the ultrasonic transducers described above, which are arranged in a common module housing. The module housing can form the mounting bracket for the two ultrasonic transducers. The two mounting brackets can be formed as one piece by the module housing. One of the ultrasonic transducers can be designed to be operated as a transmitter and the other ultrasonic transducer can be designed to be operated as a receiver.

The module housing, which forms both mounting brackets, can make it possible to arrange the two ultrasonic transducers very close to each other. This is also made possible by the fact that a wide mounting collar can be dispensed with, since the respective containers of the ultrasonic transducers are held at the front, closed end.

By using two transducers, one as a transmitter and one as a receiver, it is possible to detect objects at a very short distance from the module.

1. 1. Ein Ultraschall-Wandler aufweisend:
   • - ein Behältnis mit einer Öffnung, einem Boden, der der Öffnung gegenüberliegt, und einer Seitenwand, die den Boden mit der Öffnung verbindet,
   wobei eine axiale Richtung von der Öffnung zu dem Boden weist, wobei die Seitenwand einen ersten Bereich aufweist, in dem die Seitenwand sich in der zur axialen Richtung entgegengesetzten Richtung unmittelbar an den Boden anschließt, wobei die Seitenwand einen zweiten Bereich aufweist, der sich in der zur axialen Richtung entgegengesetzten Richtung an den ersten Bereich anschließt und bis zur Öffnung reicht,
   • - einen Schallwandler, wobei der Schallwandler innerhalb des Behältnisses auf dem Boden angeordnet ist, und
   • - eine Montagehalterung, die mit dem ersten Bereich der Seitenwand verbunden ist,
   wobei die Montagehalterung von dem gesamten zweiten Bereich der Seitenwand durch einen Luftspalt getrennt ist.
2. 2. Ultraschall-Wandler gemäß Aspekt 1, wobei die Montagehalterung mittelbar mit dem ersten Bereich der Seitenwand verbunden ist.
3. 3. Ultraschall-Wandler gemäß Aspekt 1 oder Aspekt 2, wobei die Montagehalterung über ein Entkopplungselement mit dem ersten Bereich der Seitenwand verbunden ist, wobei das Entkopplungselement die Seitenwand in dem ersten Bereich radial umschließt.
4. 4. Ultraschall-Wandler gemäß Aspekt 3, wobei das Entkopplungselement elastisch ist.
5. 5. Ultraschall-Wandler gemäß Aspekt 3 oder Aspekt 4, wobei das Entkopplungselement eine Härte von weniger als 60 Shore A aufweist.
6. 6. Ultraschall-Wandler gemäß einem der Aspekte 3 bis 5, wobei das Entkopplungselement ein ausgehärtetes Polymer, beispielsweise Silikon, aufweist.
7. 7. Ultraschall-Wandler gemäß einem der Aspekte 3 bis 6, wobei eine Tellerfeder zwischen dem Entkopplungselement und dem Luftspalt angeordnet ist.
8. 8. Ultraschall-Wandler gemäß einem der vorherigen Aspekte, wobei das Behältnis in dem zweiten Bereich der Seitenwand freischwingend ist.
9. 9. Ultraschall-Wandler gemäß einem der vorherigen Aspekte, wobei der Ultraschall-Wandler derart ausgestaltet ist, dass sich in dem ersten Bereich der Seitenwand ein Schwingungsknoten ausbildet, wenn der Schallwandler eine Ultraschallschwingung des Bodens anregt.
10. 10. Ultraschall-Wandler gemäß einem der vorherigen Aspekte, wobei der Schallwandler eine piezoelektrische Scheibe aufweist.
11. 11. Ultraschall-Wandler gemäß einem der vorherigen Aspekte, wobei der Ultraschall-Wandler einen Deckel aufweist, der das Behältnis verschließt, wobei eine Elektronik im Deckel integriert ist, und wobei die Elektronik den Schallwandler elektrisch kontaktiert und dazu ausgestaltet ist, den Schallwandler zu steuern und auszulesen.
12. 12. Ultraschall-Wandler gemäß Aspekt 11, wobei der Luftspalt eine von dem Schallwandler wegweisende Rückseite des Deckels zumindest teilweise bedeckt.
13. 13. Ultraschall-Wandler gemäß Aspekt 11 oder Aspekt 12, wobei auf einer von dem Schallwandler wegweisende Rückseite des Deckels eine Schnittstelle angeordnet ist, und wobei die von dem Schallwandler wegweisende Rückseite des Deckels mit einer Ummantelung abgedichtet ist.
14. 14. Ultraschall-Wandler gemäß einem der vorherigen Aspekte, wobei der Ultraschall-Wandler eine Anschlagssicherung aufweist, die auf der vom Boden wegweisenden Seite der Seitenwand angeordnet ist, wobei zwischen der Anschlagssicherung und der Seitenwand in einem Ruhezustand des Ultraschall-Wandlers ein Spalt ausgebildet ist, und wobei die Anschlagssicherung eine Wegstrecke begrenzt, in die die Seitenwand in axialer Richtung bewegbar ist.
15. 15. Ultraschall-Wandler gemäß einem der vorherigen Aspekte, wobei die Montagehalterung einen in einer radialen Richtung nach außen weisenden Vorsprung aufweist, an dem in axialer Richtung ein Dichtungsring anliegt.
16. 16. Ultraschall-Wandler gemäß einem der vorherigen Aspekte, wobei die Montagehalterung auf einer von dem Behältnis wegweisenden Außenseite ein Gewinde aufweist, wobei die Montagehalterung eine mit dem Gewinde verschraubte Mutter aufweist.
17. 17. Ultraschall-Wandler gemäß Aspekt 15 und Aspekt 16, wobei der Ultraschall-Wandler mit einem Gehäuse derart verbindbar ist, dass der Dichtungsring auf einer Oberseite des Gehäuses aufliegt und die Mutter gegen eine Unterseite des Gehäuses drückt.
18. 18. Ultraschall-Wandler gemäß einem der Aspekte 1 bis 15, wobei die Montagehalterung auf einer von dem Behältnis wegweisenden Außenseite Ausnehmungen aufweist, die zum Verrasten mit je einem Rasthaken ausgebildet sind.
19. 19. Ultraschall-Wandler gemäß Aspekt 15 und Aspekt 18, wobei der Ultraschall-Wandler mit einem Gehäuse derart verbindbar ist, dass der Dichtungsring auf einer Oberseite des Gehäuses aufliegt und an einer Unterseite des Gehäuses Rasthaken angeordnet sind, die mit den Ausnehmungen verrasten.
20. 20. Ultraschall-Wandler gemäß Aspekt 15, wobei der Ultraschall-Wandler mit einem Gehäuse derart verbindbar ist, dass der Dichtungsring auf einer Unterseite des Gehäuses anliegt und eine Oberseite des Gehäuses bündig mit dem Boden ist, wobei an der Unterseite Schnapphaken angeordnet sind, die die Montagehalterung gegen die Unterseite des Gehäuses drücken.
21. 21. Modul aufweisend zwei Ultraschall-Wandler gemäß einem der vorherigen Aspekte, die in einem gemeinsamen Modulgehäuse angeordnet sind.
22. 22. Modul gemäß dem vorherigen Aspekt, wobei das Modulgehäuse die Montagehalterung der beiden Ultraschall-Wandler ausbildet.
23. 23. Modul gemäß Aspekt 21 oder Aspekt 22, wobei einer der Ultraschall-Wandler dazu ausgestaltet ist, als Sender betrieben zu werden und wobei der andere der Ultraschall-Wandler dazu ausgestaltet ist, als Empfänger betrieben zu werden.

Advantageous aspects are described below. To make referencing easier, the aspects are numbered. Features of the aspects are relevant not only in combination with the specific aspect to which they refer, but also when considered separately.

1. 1. An ultrasonic transducer comprising:
   • - a container with an opening, a base opposite the opening and a side wall connecting the base to the opening,
   wherein an axial direction points from the opening to the bottom, wherein the side wall has a first region in which the side wall extends in the direction to directly adjoins the bottom in the direction opposite to the axial direction, the side wall having a second region which adjoins the first region in the direction opposite to the axial direction and extends to the opening,
   • - a sound transducer, wherein the sound transducer is arranged on the floor inside the container, and
   • - a mounting bracket connected to the first area of the side wall,
   wherein the mounting bracket is separated from the entire second region of the side wall by an air gap.
2. 2. Ultrasonic transducer according to aspect 1, wherein the mounting bracket is indirectly connected to the first region of the side wall.
3. 3. Ultrasonic transducer according to aspect 1 or aspect 2, wherein the mounting bracket is connected to the first region of the side wall via a decoupling element, wherein the decoupling element radially encloses the side wall in the first region.
4. 4. Ultrasonic transducer according to aspect 3, wherein the decoupling element is elastic.
5. 5. Ultrasonic transducer according to aspect 3 or aspect 4, wherein the decoupling element has a hardness of less than 60 Shore A.
6. 6. Ultrasonic transducer according to one of aspects 3 to 5, wherein the decoupling element comprises a cured polymer, for example silicone.
7. 7. Ultrasonic transducer according to one of aspects 3 to 6, wherein a disc spring is arranged between the decoupling element and the air gap.
8. 8. Ultrasonic transducer according to one of the preceding aspects, wherein the container is freely oscillating in the second region of the side wall.
9. 9. Ultrasonic transducer according to one of the preceding aspects, wherein the ultrasonic transducer is designed such that a vibration node forms in the first region of the side wall when the sound transducer excites an ultrasonic vibration of the floor.
10. 10. Ultrasonic transducer according to one of the preceding aspects, wherein the sound transducer comprises a piezoelectric disk.
11. 11. Ultrasonic transducer according to one of the preceding aspects, wherein the ultrasonic transducer has a lid that closes the container, wherein electronics are integrated in the lid, and wherein the electronics electrically contact the sound transducer and are designed to control and read the sound transducer.
12. 12. Ultrasonic transducer according to aspect 11, wherein the air gap at least partially covers a rear side of the cover facing away from the sound transducer.
13. 13. Ultrasonic transducer according to aspect 11 or aspect 12, wherein an interface is arranged on a rear side of the cover facing away from the sound transducer, and wherein the rear side of the cover facing away from the sound transducer is sealed with a casing.
14. 14. Ultrasonic transducer according to one of the preceding aspects, wherein the ultrasonic transducer has a stop lock which is arranged on the side of the side wall facing away from the ground, wherein a gap is formed between the stop lock and the side wall in a rest state of the ultrasonic transducer, and wherein the stop lock limits a path in which the side wall is movable in the axial direction.
15. 15. Ultrasonic transducer according to one of the preceding aspects, wherein the mounting bracket has a projection pointing outward in a radial direction, against which a sealing ring rests in the axial direction.
16. 16. Ultrasonic transducer according to one of the preceding aspects, wherein the mounting bracket has a thread on an outer side facing away from the container, wherein the mounting bracket has a nut screwed to the thread.
17. 17. Ultrasonic transducer according to aspect 15 and aspect 16, wherein the ultrasonic transducer is connectable to a housing such that the sealing ring rests on an upper side of the housing and the nut presses against a lower side of the housing.
18. 18. Ultrasonic transducer according to one of aspects 1 to 15, wherein the mounting bracket has recesses on an outer side facing away from the container, which are each designed to be locked with a locking hook.
19. 19. Ultrasonic transducer according to aspect 15 and aspect 18, wherein the ultrasonic transducer is connectable to a housing such that the sealing ring rests on an upper side of the housing and on an underside of the housing This has locking hooks that engage with the recesses.
20. 20. Ultrasonic transducer according to aspect 15, wherein the ultrasonic transducer is connectable to a housing such that the sealing ring rests on a bottom of the housing and a top of the housing is flush with the floor, wherein snap hooks are arranged on the bottom which press the mounting bracket against the bottom of the housing.
21. 21. Module comprising two ultrasonic transducers according to one of the preceding aspects arranged in a common module housing.
22. 22. Module according to the previous aspect, wherein the module housing forms the mounting bracket of the two ultrasonic transducers.
23. 23. The module of aspect 21 or aspect 22, wherein one of the ultrasonic transducers is configured to operate as a transmitter and wherein the other of the ultrasonic transducers is configured to operate as a receiver.

• 1 zeigt einen Ultraschall-Wandler in einer schematischen Ansicht.
• 2 zeigt schematisch den Einbau des Ultraschall-Wandlers in ein Gehäuse.
• 3 zeigt einen Ultraschall-Wandler gemäß einem zweiten Ausführungsbeispiel, der in ein Gehäuse einer Zielapplikation eingebaut ist.
• 4 zeigt ein dazu alternatives Ausführungsbeispiel, bei dem der Ultraschall-Wandler von einer Unterseite in ein Gehäuse eingesetzt wird.
• 5 zeigt einen Ultraschall-Wandler mit einer Ummantelung, die eine von dem Boden wegweisende Hinterseite des Behältnisses abdichtet.
• 6 zeigt ein Modul, das zwei Ultraschall-Wandler aufweist.
• 7 zeigt ein Modulgehäuse in einer perspektivischen Ansicht.

In the following, preferred embodiments are described in more detail with reference to the figures.

• 1 shows an ultrasonic transducer in a schematic view.
• 2 shows schematically the installation of the ultrasonic transducer in a housing.
• 3 shows an ultrasonic transducer according to a second embodiment, which is installed in a housing of a target application.
• 4 shows an alternative embodiment in which the ultrasonic transducer is inserted into a housing from the bottom.
• 5 shows an ultrasonic transducer with a casing that seals a rear side of the container facing away from the bottom.
• 6 shows a module that has two ultrasonic transducers.
• 7 shows a module housing in a perspective view.

1 shows an ultrasonic transducer 1. The ultrasonic transducer has a pot-shaped container 2 which has an opening, a base 3 and a side wall 4. An axial direction A is defined as the direction from the base 3 to the opening. The container 2 can have a conductive material, for example aluminum or a conductive plastic or a conductively coated plastic, or a non-conductive material, for example a plastic, in particular a fiber-reinforced plastic. In the following, "in the axial direction at the front" always refers to a direction pointing towards the base 3. "In the axial direction at the rear" always refers to a direction pointing towards the opening.

The side wall 4 is made up of two cylindrical parts, 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 round base with the bottom 3, which also serves as a membrane. The front part is open in an axial direction A to the rear. The entire container 2 is in one piece and the rear part 6 is connected to the front part 5 via a connecting surface 7 that runs 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.

Inside the container 2, a sound transducer 9, for example a piezoelectric disk, is arranged on the base 3. The sound transducer 9 is fixed to the base 3 with an adhesive layer or an adhesive disk. A damping element 10 is arranged above this, which is adapted to the shape of the container 2 and fills it completely. The sound transducer 9 is connected to an electronics 12 via wires 11 or via a contact on the inside of the container 2. This is arranged on a side of the lid 8 that faces inwards. The lid 8 itself is a circuit board. The lid 8 has an interface 13, for example a digital I/O interface, on a side that faces outwards. The interface 13 has a connection plug.

The interface 13 not only enables external communication, but also supplies the electronics 12 and the sound transducer 9 with electricity. The arrangement of the interface 13 on the cover 8 enables a compact design of the ultrasonic transducer 1 and simple contacting, since no further connections need to be considered.

The ultrasonic transducer 1 further comprises a mounting bracket 14. The mounting bracket 14 is a sleeve-shaped element which encloses the container 2. In the axial direction A at the front, a front end of the mounting bracket 14 is arranged in the same plane as the base 3 of the container 2. In the axial direction A at the rear, the mounting bracket 14 projects beyond the container 2.

The mounting bracket 14 has an inwardly projecting projection 15 and an outwardly projecting projection 16 at a front end in the axial direction. Due to the two projections 15, 16, the wall thickness of the mounting bracket 14 is greater at its front end than in the remaining area of the mounting bracket.

In the 1 In the embodiment shown, the inwardly projecting projection 15 is flush with the rear part 6 of the side wall 4 in the axial direction. In an alternative embodiment, the inwardly projecting projection 15 can overlap the rear part 6. In a further alternative embodiment, the inwardly projecting projection 15 can be designed so short that it does not overlap with the rear part 6.

In the remaining area, the mounting bracket 14 has a sleeve shape, the diameter of which is smaller than a maximum diameter of the outwardly projecting projection 16. On an outer side 17 facing away from the container, the mounting bracket has a thread 18 and/or recesses 19 for engaging locking hooks 33. In the 1 In the embodiment shown, the mounting bracket 14 has a thread 18 and recesses 19. In alternative embodiments, it may have only one selected from the thread 18 and the recesses 19.

An inner side 21 of the mounting bracket 14 facing the container is designed as a flat wall in the area in which the side wall 4 is sleeve-shaped.

A surface of the outwardly projecting projection 16 formed at the rear in the axial direction A forms a stop surface 22. A sealing ring 30 can rest against the stop surface 22 during assembly of the ultrasonic transducer 1.

The mounting bracket 14 is connected to the side wall 4 of the container 2. The side wall 4 is divided into a first region 24 and a second region 25. The side wall 4 can be constructed from the first region 24 and the second region 25.

The first region 24 is the region in which the side wall 4 is connected to the mounting bracket 14. In particular, the inwardly projecting projection 15 of the mounting bracket 14 is connected to the side wall 4.

The second area 25 is the area in which the side wall 4 is not connected to the mounting bracket 14, but is separated from it by an air gap 26. The inner side 21 of the mounting bracket 14 is separated from the side wall 4 in the second area 25 by the air gap 26. The air gap 26 ensures structure-borne sound decoupling between the second area 25 of the side wall 4 and the mounting bracket 14.

The first region 24 of the side wall 4 is a region in which the side wall 4 directly adjoins the base 3 in a direction opposite to the axial direction A. A vibration node forms in the first region 24 when the sound transducer 9 is excited to vibrate and the container 2 is thereby set into vibration. The second region 25 of the side wall 4 is a region that includes the end of the side wall 4 pointing away from the base 3. A vibration antinode forms in the second region 25 when the sound transducer 9 is excited to vibrate and the container 2 is thereby set into vibration.

The fastening of the mounting bracket 14 in the first region 24 ensures that a vibration of the container 2 is only minimally dampened by the mounting bracket 14, since the mounting bracket 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. If, on the other hand, the mounting bracket 14 were connected to the side wall 4 in the region of the vibration antinode, the mounting bracket 14 would severely disrupt a vibration of the container 2.

Structure-borne noise generated in the container 2 is only transmitted to the mounting bracket 14 to a small extent by the connection of the mounting bracket 14 to the first area 24 of the side wall 4. Conversely, if the mounting bracket 14 is mounted in an external housing of a target application, structure-borne noise generated in the target application is only transmitted to the container 2 of the ultrasonic transducer 1 to a very small extent. The mounting bracket 14 thus enables the oscillating part of the ultrasonic transducer 1 to be mounted in a way that is decoupled from structure-borne noise.

The container 2 is essentially free-swinging relative to the mounting bracket 14. This results in a free-swinging air gap suspension. The free-swinging air gap suspension is limited in movement by the decoupling element 27 described below and the stop lock 28 described below.

The target application can be, for example, the bumper of a vehicle or the front of a robot, such as a robotic lawnmower.

In the 1 In the embodiment shown, 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 only be connected to a partial region of the front part 5. The first region 24 can thus be made smaller in this alternative embodiment and only comprise a part of the front part 5.

The mounting bracket 14 is connected in the first area 24 to the container 2 indirectly via a decoupling element 27. The decoupling element 27 is ring-shaped. The decoupling element 27 encloses the first area 24 of the side wall 4 in a ring shape. The decoupling element 27 rests on the inner side 21 of the mounting bracket 14. In particular, the decoupling element 27 rests on the inwardly projecting projection 15 of the mounting bracket 14. The decoupling element 27 is glued to the mounting bracket 14 and the side wall 4 and thereby connects the mounting bracket 14 and the side wall 4.

The decoupling element 27 comprises an elastic material. The decoupling element 27 can comprise a cured polymer, for example a silicone or a silicone elastomer.

The decoupling element 27 can have a hardness of less than 60 Shore A. The decoupling element 27 is produced in a casting process in which liquid material is poured into a gap between the mounting bracket 14 and the container 2. The liquid material hardens and forms the decoupling element 27. This process makes it possible to precisely arrange a decoupling element 27 with such a low hardness. Alternatively, the decoupling element 27 could be manufactured or assembled using a joining technique or another manufacturing process.

Due to the low hardness of the decoupling element 27, this allows relative movements with a small movement amplitude of the mounting bracket 14 and the container 2 to one another. The decoupling element 27 limits the distance by which the container 2 can be moved forwards in the radial direction and in the axial direction relative to the mounting bracket 14.
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 liquid material does not penetrate into the air gap 26 during the casting process. The disc spring 29 seals the air gap 26 against the decoupling element 27.

The ultrasonic transducer 1 further comprises a stop lock 28 which is arranged in the axial direction behind the container 2 and is separated from the container 2 by an air gap 26 when the ultrasonic transducer 1 is in a rest state. The rest state is defined as a state in which no external force is exerted on the container 2.

The stop safety device 28 ensures that the distance over which the container 2 can be moved backwards in the axial direction A is limited. This ensures that a force exerted on the container 2 in the axial direction A does not lead to damage to the ultrasonic transducer 1.

2 shows an installation of an ultrasonic transducer 1 according to a first embodiment in an external housing 32 of a target application in a schematic view.

The ultrasonic transducer 1 has a sealing ring 30 which rests against the stop surface 22 of the outwardly projecting projection 16 of the mounting bracket 14. The sealing ring 30 is an O-ring. The sealing ring 30 has an elastic material. By means of the sealing ring 30, a simple and at the same time secure seal against dust and water can be achieved which meets the requirements of the IP classes. The sealing ring 30 forms a simple pinch seal without requiring additional components.

The mounting bracket 14 has the 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 bracket 14.

A free area is formed between the sealing ring 30 and the nut 31. If the ultrasonic transducer 1 is now installed in a housing 32 of a target application, the housing 32 can be arranged in this free area. The sealing ring 30 rests on an upper side of the housing 32 and the nut 31 presses against the housing 32 from an underside, so that the sealing ring 30 is squeezed by the housing 32 and thus sealed.

3 shows an ultrasonic transducer 1 according to a second embodiment, which is installed in a housing 32 of a target application. In contrast to the first embodiment, the outer side 17 of the mounting bracket 14 has no thread 18. The mounting bracket 14 has several recesses 19, which are designed to engage with locking hooks 33 of the housing 32.

The housing 32 has corresponding locking hooks 33 on its underside. If the ultrasonic transducer 1 is installed in the housing 32, the sealing ring 30 rests on an upper side of the housing 32. The locking hooks 33 on the underside of the housing 32 are locked into the recesses 19 of the mounting bracket 14. The sealing ring 30 is pressed together by the outwardly projecting projection 16 of the mounting bracket 14 and the housing 32 and the connection is sealed. The mounting bracket 14 can, for example, have three recesses 19. The mounting bracket 14 can have any other number of recesses 19. The housing 32 has a number of locking hooks 33 that corresponds to the number of recesses 19 of the mounting bracket 14.

In the 2 and 3 In the embodiment shown, the ultrasonic transducer 1 is inserted into an upper side of the housing 32 and is either screwed from the underside via the nut 31 or clamped by engaging the locking hooks 33. 4 shows an alternative embodiment in which the ultrasonic transducer 1 is inserted into the housing 32 from the bottom.

The mounting bracket 14 has an outwardly projecting projection 16 which is formed in the axial direction in a central region of the mounting bracket 14. The sealing ring 30 rests in the axial direction on a front side of the outwardly projecting projection 16. When the ultrasonic transducer 1 is mounted in the housing 32, the sealing ring 30 is squeezed between the underside of the housing 32 and the front side of the outwardly projecting projection 16. In addition, snap hooks 34 are formed on the underside of the housing 32, which can be connected to the underside of the container 2 and press the container 2 towards the underside of the housing 32. The bottom 3 of the container 2 and a top of the housing 32 can be arranged flush with one another.

In the 2 to 4 In the installation variants shown, an outer housing separate from the mounting bracket 14 can be dispensed with when installing the ultrasonic transducer 1 in the housing 32. Instead, the ultrasonic transducer 1 can be mounted directly into a target object using the mounting bracket 14. Since the electronics 17 for control are also installed in the ultrasonic transducer 1 itself, any additional components can be dispensed with. In this way, a simple, inexpensive, resilient and compact overall system can be constructed.

5 shows an ultrasonic transducer 1 with a casing 35, which seals a rear side of the container 2 facing away from the base 3. The casing 35 can provide protection against dirt, dust and water. A cable guide 36 can be formed in the casing 35, via which the interface 13 can be contacted. The casing 35 can be connected directly to the nut 31. A 5 The casing 35 shown can be combined with any of the previously shown embodiments. In the embodiments that do not have a nut 31, the casing 35 can be connected directly to the mounting bracket 14.

6 shows a module that has two ultrasonic transducers 1. The two ultrasonic transducers 1 are arranged in a common module housing 37. The module housing 37 forms the two mounting brackets 14 of the ultrasonic transducers 1. The two mounting brackets 14 are thus formed in one piece. In an alternative embodiment of the module, more than two ultrasonic transducers 1 can be arranged in a common module housing 37.

The connection of the mounting brackets 14 to the container 2 via the decoupling element 27 and the integral formation of several mounting brackets 14 through the module housing 37 enable a compact design of the module. This allows two or more ultrasonic transducers 1 to be arranged in close spatial proximity to one another.

One of the two ultrasonic transducers 1 can be used as an ultrasonic transmitter and the other of the two ultrasonic transducers 1 can be used as an ultrasonic receiver. Such a module makes it possible to detect objects at a very short distance. This would not be possible if only a single ultrasonic transducer 1 was used as a transmitter and receiver, since after transmission, the membrane would first have to be allowed to resonate before the ultrasonic transducer 1 can be used to detect a reflection.

7 shows the module housing 37 in a perspective view.

Reference symbols

1

Ultrasonic transducer

2

container

3

Floor

4

Side wall

5

front part

6

back part

7

Connection surface

8th

Lid

9

Transducer

10

Damping element

11

wire

12

electronics

13

interface

14

Mounting bracket

15

inward protrusion

16

outward protrusion

17

Outside

18

thread

19

Recess

21

inside

22

Stop surface

24

first area

25

second area

26

Air gap

27

Decoupling element

28

Stop protection

29

Disc spring

30

Sealing ring

31

Mother

32

Housing

33

Latching hook

34

Snap hook

35

Sheathing

36

Cable routing

37

Module housing

A

axial direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• WO 2020245064 A2 [0004]
• DE 102020132631 A1 [0005]
• DE 102021200639 A1 [0005]
• DE 102016221535 A1 [0005]

Claims (22)

An ultrasonic transducer (1) comprising: - a container (2) with an opening, a base (3) which is opposite the opening, and a side wall (4) which connects the base (3) to the opening, wherein an axial direction (A) points from the opening to the base (3), wherein the side wall (4) has a first region (24) in which the side wall (4) directly adjoins the base (3) in the direction opposite to the axial direction (A), wherein the side wall (4) has a second region (25) which adjoins the first region (24) in the direction opposite to the axial direction (A) and extends to the opening, - a sound transducer (9), wherein the sound transducer (9) is arranged on the base (3) within the container (2), and - a mounting bracket (14) which is connected to the first region (24) of the side wall (4), wherein the mounting bracket (14) is the entire second region (25) of the side wall (4) is separated by an air gap (26), wherein the ultrasonic transducer (1) has a stop lock (28) which is arranged on the side of the side wall (4) facing away from the base (3), wherein a gap is formed between the stop lock (28) and the side wall (4) in a resting state of the ultrasonic transducer (1), and wherein the stop lock (28) limits a path in which the side wall (4) can be moved in the axial direction. Ultrasonic transducer (1) according to Claim 1 , wherein the mounting bracket (14) (24) is indirectly connected to the first region (24) of the side wall (4). Ultrasonic transducer (1) according to Claim 1 or Claim 2 , wherein the mounting bracket (14) is connected to the first region (24) of the side wall (4) via a decoupling element (27), wherein the decoupling element (27) radially encloses the side wall (4) in the first region (24). Ultrasonic transducer (1) according to Claim 3 , wherein the decoupling element (27) is elastic. Ultrasonic transducer (1) according to Claim 3 or Claim 4 , wherein the decoupling element (27) has a hardness of less than 60 Shore A. Ultrasonic transducer (1) according to one of the Claims 3 until 5 , wherein the decoupling element (27) comprises a cured polymer, for example silicone. Ultrasonic transducer (1) according to one of the Claims 3 until 6 , wherein a disc spring (29) is arranged between the decoupling element (27) and the air gap (26). Ultrasonic transducer (1) according to one of the preceding claims, wherein the container (2) is freely oscillating in the second region (25) of the side wall (4). Ultrasonic transducer (1) according to one of the preceding claims, wherein the ultrasonic transducer (1) is designed such that a vibration node forms in the first region (24) of the side wall (4) when the sound transducer (9) excites an ultrasonic vibration of the floor (3). Ultrasonic transducer (1) according to one of the preceding claims, wherein the sound transducer (9) comprises a piezoelectric disk. Ultrasonic transducer (1) according to one of the preceding claims, wherein the ultrasonic transducer (1) has a lid (8) which closes the container (2), wherein electronics (12) are integrated in the lid (8), and where the electronics (12) electrically contact the sound transducer (9) and are designed to control and read out the sound transducer (9). Ultrasonic transducer (1) according to Claim 11 , wherein the air gap (26) at least partially covers a rear side of the cover (8) facing away from the sound transducer (9). Ultrasonic transducer (1) according to Claim 11 or Claim 12 , wherein an interface (13) is arranged on a rear side of the cover (8) facing away from the sound transducer (9), and wherein the rear side of the cover (8) facing away from the sound transducer (9) is sealed with a casing (35). Ultrasonic transducer (1) according to one of the preceding claims, wherein the mounting bracket (14) has a projection (16) pointing outwards in a radial direction, against which a sealing ring (30) rests in the axial direction. Ultrasonic transducer (1) according to one of the preceding claims, wherein the mounting bracket (14) has a thread (18) on an outer side (17) facing away from the container (2), wherein the mounting bracket (14) has a nut (31) screwed to the thread (18). Ultrasonic transducer (1) according to Claim 14 and Claim 15 , wherein the ultrasonic transducer (1) can be connected to a housing such that the sealing ring (30) rests on an upper side of the housing and the nut (31) presses against an underside of the housing. Ultrasonic transducer (1) according to one of the Claims 1 until 14 , wherein the mounting bracket (14) has recesses (19) on an outer side (17) facing away from the container (2), which are designed to be locked with a locking hook (33) each. Ultrasonic transducer (1) according to Claim 14 and Claim 17 , wherein the ultrasonic transducer (1) can be connected to a housing (32) in such a way that the sealing ring (30) rests on an upper side of the housing (32) and latching hooks (33) are arranged on an underside of the housing (32), which latch into the recesses (19). Ultrasonic transducer (1) according to Claim 14 , wherein the ultrasonic transducer (1) can be connected to a housing (32) in such a way that the sealing ring (30) rests on an underside of the housing (32) and an upper side of the housing (32) is flush with the base (3), wherein snap hooks (34) are arranged on the underside, which press the mounting bracket (14) against the underside of the housing (32). Module comprising two ultrasonic transducers (1) according to one of the preceding claims, which are arranged in a common module housing (37). Module according to the preceding claim, wherein the module housing (37) forms the mounting bracket (14) of the two ultrasonic transducers (1). Module according to Claim 20 or Claim 21 , wherein one of the ultrasonic transducers (1) is designed to be operated as a transmitter and wherein the other of the ultrasonic transducers (1) is designed to be operated as a receiver.