DE102019124989A1 - Transmission arrangement for the transmission of electrical energy with piezoelectric transducers - Google Patents

Abstract

A transmission arrangement (1) has a primary piezoelectric transducer (2), a secondary piezoelectric transducer (3) and a wall (4) for transmitting an acoustic signal between the transducers (2, 3), at least one of the transducers (2, 3) can be detachably attached to the wall (4). The attachment can for example be designed mechanically or magnetically.

Description

The present invention relates to a transmission arrangement for transmitting electrical energy. In particular, electrical energy is transmitted from a piezoelectric transducer via an acoustic channel to a further piezoelectric transducer, where it is converted back into electrical energy. The acoustic signal is in particular in the ultrasonic frequency range.

Such a transmission arrangement makes it possible to record processes by measuring technology and to control processes, even if they take place in an environment that is difficult to access, such as in a closed container or other cavity structures. In particular, electrical power can be introduced or made available in a closed cavity. Such structures can be found, for example, in industrial and process engineering, such as the oil and gas industry, in aircraft, ships and submarines.

The transmission of electrical energy into a cavity often takes place via cable bushings in which holes are drilled into a wall of a cavity. However, the introduction of holes violates the structural integrity of the closed containers and often requires maintenance. In addition, the weight and size of the bushings and cables can interfere. Furthermore, specific operating conditions in the container, such as high temperatures and high pressure, lead to a high failure rate for cable penetrations.

Alternatively, energy can also be stored in the cavity by means of a battery. However, the amount of energy introduced is limited and must be designed for the duration of the process or the service life of the respective device. In addition, certain operating conditions, such as high or low temperatures, have an unfavorable effect on the service life of the battery. In addition, the weight and size of the battery and the maintenance required may be inconvenient.

Alternatively, thermoelectric elements can also be used that use temperature differences on the inner walls of a container to generate electrical power. However, this assumes the existence of temperature differences. In addition, the weight and size of the elements can also be a nuisance here. In addition, the efficiency of energy generation at, for example, 5% is often insufficient.

Radioactive substances can also be used to generate heat and electrical power from a resulting temperature difference. However, the handling of such substances is risky.

Transmission arrangements are known in which transducers are used for sending and receiving a signal or energy via an acoustic channel. The converters are, for example, piezoelectric converters. The acoustic channel is, for example, a metallic wall of a container.

Such transmission arrangements are, for example, in the review article by Ding-Xin Yang, Zheng Hu, Hong Zhao, Hai-Feng Hu, Yun-Zhe Sun and Bao-Jian Hou: "Through-Metal-Wall Power Delivery and Data Transmission for Enclosed Sensors: A Review" in Sensors 2015, 15, 31581-31605 described.

It is an object of the present invention to specify an improved transmission arrangement having piezoelectric transducers.

A transmission arrangement is specified which has a primary piezoelectric transducer, a secondary piezoelectric transducer and a medium for transmitting an acoustic signal between the transducers. In particular, the medium forms an acoustic channel for transmitting the signal. The medium is arranged between the transducers.

One of the converters can be used to convert an electrical signal into an acoustic signal and the other converter can be used to convert the acoustic signal into an electrical signal. The converter, which converts the electrical signal into an acoustic signal, can serve as a transmitter and the converter, which converts the acoustic signal into an electrical signal, can serve as a receiver. For example, the primary piezoelectric transducer is the transmitter and the secondary piezoelectric transducer is the receiver. It is also possible that the primary piezoelectric transducer acts as a receiver and the secondary piezoelectric transducer acts as a transmitter, or that the transducers act simultaneously or alternately as transmitter and receiver.

The transmission arrangement is particularly suitable for the transmission of energy or signals in the close range, i.e. over a short distance, for example in the millimeter range. The energy or the signal is transmitted between the transmitter and receiver without electrical contact.

The medium can be a wall, for example a metallic wall. The wall forms, for example, the wall of a closed container or other cavity structure. The wall has a metal or is made of metal, for example. The wall can in particular comprise aluminum or consist of aluminum. The wall can also be made non-metallic. The wall can be designed to be electrically conductive or electrically non-conductive.

For example, the primary piezoelectric transducer is arranged in an outer space of the container and the secondary piezoelectric transducer is arranged in an inner space of the container. However, the secondary transducer can also be arranged in the outside space and the primary transducer in the inside space. It is also possible for none of the transducers to be arranged in a closed container.

In certain aspects of the invention, the medium can also be configured as a gaseous medium, such as, for example, air, or as a liquid medium.

The piezoelectric transducers each have, for example, a structure made up of electrode layers and at least one piezoelectric layer located in between. There can only be a single piezoelectric layer. Alternatively, a plurality of piezoelectric layers can also be present alternating with electrode layers. For example, at least one of the transducers has a multilayer structure made up of alternately arranged electrode layers and piezoelectric layers. The piezoelectric layers can in particular be ceramic layers. The electrode layers and piezoelectric layers can be sintered together.

According to one aspect of the present invention, the transmission arrangement has a wall for transmitting an acoustic signal between the transducers. The medium is thus designed as a wall. At least one of the transducers can be detachably attached to the wall. In particular, the removable transducer is designed to be repeatedly removed and reattached to the wall. For example, the detachable transducer is not glued to the wall.

Both transducers can be removably attached to the wall. This is advantageous, for example, when none of the transducers is arranged in a closed housing. It is also possible for only one of the transducers to be designed for removable attachment and the other transducer for non-removable attachment. For example, the primary transducer is removably attachable. For example, one of the transducers is arranged and removably attached in an exterior space, while the other transducer is arranged in an interior space and permanently attached.

According to one embodiment, the detachable transducer is magnetically attachable to the wall. For example, the transmission arrangement has a transducer unit which has one of the transducers and a magnet and can be attached and detached as a whole to the wall. For example, a magnet is permanently attached to the removable transducer. The magnet can be glued to the transducer. The arrangement is held between the magnet and a magnetic wall, for example by means of the magnetic force.

Both transducers can also be magnetically fastened to the wall. For example, a magnet is arranged between the transducer and the wall in both transducers.

The magnet can be electrically conductive. In addition to the function of fastening the transducer to the wall, the magnet can also have the function of a contact for making electrical contact with the transducer.

In one embodiment, the transmission arrangement has at least one holder for the removable attachment of at least one transducer to the wall. For example, the holder and / or the transducer has a latching mechanism for releasable latching with the transducer. It is therefore a mechanical fastening. For example, the bracket is permanently attached to the wall.

For example, the holder has an underside on which the transducer can be placed, and side parts that hold the transducer laterally. For example, the transducer can be pushed into the holder from above. The transducer can also be inserted into the holder perpendicular to the wall. As with a magnetic holder, both transducers or only one of the transducers can be removably attachable in holders. There can also be a combination of magnetic and mechanical fastening.

The holder can be electrically conductive or have an electrically conductive area or an electrically conductive element. The holder can also be designed as a contact for making electrical contact with the transducer.

In one embodiment, the transmission arrangement has an adaptation layer for adapting phase positions and / or for guiding the acoustic signal. The adaptation layer is arranged, for example, between one of the transducers and the acoustic medium, in particular the wall. There can also be an adaptation layer between the two transducers and the wall be arranged. The adaptation layer can also have a multilayer design.

Due to the spatial extent of the transducers, different signal components of the acoustic signal emanating from a transducer and / or the acoustic signal received by a transducer can have different phase positions. The adaptation layer can be designed in such a way that the phase positions of the components are as identical as possible at a desired location, so that destructive interference is avoided.

As an alternative or in addition to this, the adaptation layer can also serve to guide, in particular to focus, the signal. For example, there can be a conical widening of the acoustic signal from the primary side to the secondary side. This can be the case in particular when the acoustic channel reaches a certain length, corresponding to the thickness of the wall.

The adaptation layer can be electrically conductive. In addition to the function of adapting phase positions and / or for guiding the acoustic signal, the adaptation layer can also have the function of a contact for making electrical contact with the transducer.

For example, the adaptation layer has a homogeneous thickness, in particular in an area directly between the transducer and the wall. Alternatively, the adaptation layer can have an inhomogeneous thickness, in particular if the wall is uneven. In this case, the adaptation layer can compensate for different transit times due to the unevenness.

The adaptation layer can have a structured surface or a structured volume. For example, through the structuring, signal components can be specifically amplified, weakened or deflected, e.g. depending on the origin of the signal or frequency. The structured surface is formed in particular on a side facing away from the wall.

The adaptation layer has, for example, an acoustic meta-material. Such a meta-material has a honeycomb-like structure, for example. For example, the meta-material is made by 3D printing. Such a meta-material can also be used as a lens to focus the signal.

In one embodiment, the adaptation layer is designed as an adhesive layer. For example, the adhesive layer is designed at the same time to attach one of the transducers to the wall. The adhesive layer can also attach the transducer to a magnet.

The adaptation layer can also be present in addition to an adhesive layer. The adaptation layer can be glued to the transducer, for example. The adaptation layer can also be attached to the transducer in some other way, for example by joint sintering with the layers of the transducer. It is also possible for a transducer to have only an adaptation layer and no adhesive layer.

In one embodiment, the adaptation layer can be designed in the manner of a gel. For example, it is an ultrasonic contact gel. In this way, the coupling from the converter to the wall can be optimized. Such a gel can, for example, be used well for mechanical mounting of the transducer or also for magnetic mounting. For example, the gel is not designed as an adhesive layer and cannot attach the transducer to the wall.

In one embodiment, one of the transducers has a larger footprint than the other transducer. For example, the transducer that receives the signal has a larger footprint than the transducer that transmits the signal. The receiver is, for example, the secondary converter. In this case, even if the signal is widened during transmission through the medium, the largest possible proportion can be received. A high electrical power efficiency, i.e. a good ratio of the received electrical line to the supplied electrical power, is thus achieved.

In one embodiment, at least one of the transducers has a geometry which is designed to reduce undesired oscillation modes. Such undesired oscillation modes absorb energy, but do not pass it on to the secondary side and thus lead to power losses. By reducing undesired vibration modes, the transmission of the acoustic wave, the propagation vector of which runs normal to the plane of the transducer and perpendicular through the wall, is optimized.

For example, at least one of the transducers has a base in the form of a polygon, the polygon being free of mutually parallel edges. The creation of radial-extensional modes is favored by parallel edges. By avoiding parallel edges, these oscillation modes can be reduced. For example, the primary transducer has such a base area. As an alternative or in addition, the secondary converter can also have such a base area. To further avoid special resonance modes, it is advantageous if the edges also have different lengths. In particular, the base area has the shape of a polygon which is free of mutually parallel edges and / or is free of edges of the same length.

For example, at least one of the transducers has different thicknesses. The thickness is in particular the thickness of the piezoelectric material. The thickness is in particular the extension of the transducer perpendicular to the medium or a wall. For example, at least one of the transducers has a greater thickness at the edge than in a central area. For example, the transducer has an elevation all around the edge. In this way, surface waves can be reduced along the surface of the wall.

The transmission arrangement can have further components, such as control electronics. For example, on the primary side there is control electronics for adapting an electrical input signal to a resonance frequency of the primary transducer and / or the transmission arrangement. The control electronics and other components can be arranged in one unit with the assigned converter. For example, the components are arranged in a common housing. For example, in the case of a detachable transducer, the entire unit can be detached and attached.

A transmission arrangement is also specified, comprising a primary piezoelectric transducer, a secondary piezoelectric transducer and a wall for transmitting an acoustic signal between the transducers, at least one of the transducers being magnetically or mechanically attached to the wall. The transmission arrangement can have all of the properties described above.

The transducer, which is located in the interior of a closed container, can also be attached to the wall via a magnet or a mechanical holder, even if the transducer cannot be removed from the wall due to lack of accessibility from the outside. Such an attachment can be less temperature sensitive compared to an adhesive attachment.

According to a second aspect of the invention, a transmission arrangement is specified which has a primary piezoelectric transducer, a secondary piezoelectric transducer and a medium for transmitting an acoustic signal. The medium can be, for example, a wall, in particular a solid wall, or a gaseous or liquid medium. The transmission arrangement has at least one adaptation layer for adapting the phase positions and / or for guiding the acoustic signal. The transducers, the medium and the adaptation layer can otherwise be designed as described above. In contrast to the first aspect of the invention, both transducers can also be attached to a wall in a non-removable manner, or a medium other than a wall can be present.

According to a third aspect of the invention, a transmission arrangement is specified which has a primary piezoelectric transducer, a secondary piezoelectric transducer and a medium for transmitting an acoustic signal. The medium can be, for example, a wall, in particular a solid wall, or a gaseous or liquid medium. At least one of the transducers has a geometry for reducing undesired oscillation modes. The transducers, the medium and the special geometry can otherwise be designed as described above. For example, the transducer has a base in the form of a polygon, the polygon being free of mutually parallel edges, or the transducer has different thicknesses. In contrast to the first aspect of the invention, both transducers can also be attached to a wall in a non-removable manner, or a medium other than a wall can be present.

According to a fourth aspect of the invention, a transducer for a transmission arrangement for transmitting electrical energy via an acoustic channel is specified, the transducer having a geometry for reducing undesired oscillation modes. The converter can otherwise be designed like one of the converters of the transmission arrangement described above. For example, the transducer has a base in the form of a polygon, the polygon being free of mutually parallel edges, or the transducer has different thicknesses. In contrast to the third aspect of the invention, the converter does not have to be part of a transmission arrangement, but only has to be suitable for it.

According to a fifth aspect of the invention, a transmission arrangement is specified which has a primary piezoelectric transducer, a secondary piezoelectric transducer and a medium for transmitting the acoustic signal. The medium can be, for example, a wall, in particular a solid wall, or a gaseous or liquid medium. The secondary transducer has a larger footprint than the primary transducer. The transducers, the medium and the base area can otherwise be designed as described above. In contrast to the first aspect of the invention, can also both transducers can be attached to a wall in a non-removable manner, or a medium other than a wall can be present.

Several aspects of an invention are described in the present disclosure. All properties that are disclosed in relation to one of the transmission arrangements, one of the transducers or a method are also disclosed correspondingly in relation to the other aspect, even if the respective property is not explicitly mentioned in the context of the other aspects.

The description of the subjects specified here is not restricted to the individual specific embodiments. Rather, the features of the individual embodiments can be combined with one another, insofar as it is technically reasonable.

In the following, the subjects described here are explained in more detail using schematic exemplary embodiments.

• 1 eine Übertragungsanordnung in schematischer Ansicht,
• 2 ein Diagramm zur Transmission in Abhängigkeit von der Frequenz,
• 3 eine Ausführungsform einer Übertragungsanordnung in einer Schnittansicht,
• 4 eine weitere Ausführungsform einer Übertragungsanordnung in einer Schnittansicht,
• 5 eine weitere Ausführungsform einer Übertragungsanordnung in einer Schnittansicht,
• 6 eine Ausführungsform eines Wandlers in Aufsicht auf eine Seitenfläche,
• 7 eine Ausführungsform eines Wandlers im Querschnitt,
• 8 eine weitere Ausführungsform einer Übertragungsanordnung in schematischer Ansicht,
• 9 eine weitere Ausführungsform einer Übertragungsanordnung in schematischer Ansicht.

Show it:

• 1 a transmission arrangement in a schematic view,
• 2 a diagram of the transmission as a function of the frequency,
• 3 an embodiment of a transmission arrangement in a sectional view,
• 4th a further embodiment of a transmission arrangement in a sectional view,
• 5 a further embodiment of a transmission arrangement in a sectional view,
• 6th an embodiment of a transducer in a plan view of a side surface,
• 7th an embodiment of a transducer in cross section,
• 8th a further embodiment of a transmission arrangement in a schematic view,
• 9 a further embodiment of a transmission arrangement in a schematic view.

In the following figures, the same reference symbols preferably refer to functionally or structurally corresponding parts of the various embodiments.

1 shows a transmission arrangement 1 for the transmission of electrical energy and / or signals. In particular, these are signals in the ultrasonic range. The transmission arrangement is used, for example 1 to transfer electrical energy from the outside into a closed container without holes for cable bushings having to be made in the container.

The transmission arrangement 1 has a primary piezoelectric transducer 2 and a secondary piezoelectric transducer 3 on. For example, the converter 2 , 3 a multilayer structure consisting of several piezoelectric layers and electrode layers in between. This can be used for an advantageous transformation of the electrical power.

Between the piezoelectric transducers 2 , 3 there is a wall 4th . The wall 4th comprises a metal, for example, or consists of metal. In particular, it is the wall 4th around a solid. The wall 4th for example comprises aluminum or consists of aluminum. The wall has a thickness of 2 mm, for example. The wall 4th can also be made non-metallic. According to specific aspects of the invention, another medium, for example a gaseous or liquid medium, can also be present instead of a solid wall.

For example, the wall forms 4th a wall of a closed container or is part of such a wall. For example, there is the primary transducer 2 in an outer space of the container and the secondary transducer 3 in an interior of the container. The primary converter 2 electrical energy can be supplied. The piezoelectric material of the transducer is deformed in the process 2 . In particular, an acoustic wave is generated across the wall 4th to the secondary converter 3 and through the piezoelectric material of the secondary transducer 3 is converted back into electrical energy. Thus, the energy is transmitted through an acoustic channel through the wall 4th through. The acoustic wave has a frequency in the ultrasonic range, for example. For example, the acoustic signal is designed as a sinusoidal pressure wave.

The primary converter 2 acts as a transmitter and the secondary converter 3 as receiver. But it is also possible that the primary converter 2 acts as a receiver and the secondary converter 3 acts as a transmitter or that the primary transducer 2 and the secondary converter 3 act simultaneously or alternately as sender and receiver.

The converters 2 , 3 are designed as MEMS components, for example, so that very small footprints can be achieved. Around a well-bundled signal cone from the primary to the secondary piezoelectric transducer 2 , 3 to the wall 4th to produce should be the diameter d_p , d_s of the two converters 2 , 3 however, have a certain minimum size depending on the acoustic wavelength. For example, the diameter is d_p , d_s the converter 2 , 3 each at least 20 times larger than the acoustic wavelength.

For example, the acoustic wavelength is in the range of 100 µm. For example, the transducers each have a diameter d_p , d_s from 1 to 10 mm. It can be an average diameter. For example, the converters 2 , 3 disc-like.

The converters 2 , 3 can be detachable on the wall 4th be attached. The details of the attachment can be, for example, the 9 and 10 remove.

2 shows a diagram of the transmission S. (in decibels) and the Fourier transform F. (in decibels) of the impulse response as a function of the frequency f (in Hz) with a transmission arrangement according to 1 .

The diagram illustrates the dependence of the filter characteristics on the thicknesses t_p , t_s the converter 2 , 3 and the fat one t w the wall 4th . For example, the wall has 4th a thickness in the range of 2 mm and the transducers 2 , 3 have thicknesses in the range of 0.2 mm.

Overall, the thickness of the arrangement, in particular the transducer, is reduced 2 , 3 and the wall 4th , to a widening of the distance between the frequency peaks, as can be shown with a simulation. The frequency peaks, corresponding to the resonance frequencies, are cavity modes in the material of the wall 4th and depend essentially on the thickness of the wall 4th from.

On the other hand, it affects the thickness of the piezoelectric transducer 2 , 3 directly the impulse response in the time domain. This changes the shape of the envelope of the transfer function in the frequency domain.

This results, depending on the thickness of the transducers 2 , 3 a frequency range in which the resonances allow particularly efficient energy transfer. An efficient resonance point is circled. In the present case, the transmission is at a maximum.

Overall, efficient transmission of electrical power through the acoustic channel (wall) can be achieved if the transmission arrangement 1 is operated at a suitable resonance frequency, in particular an efficient resonance point.

It is particularly favorable if the primary converter 2 and the secondary converter 3 have the same resonance frequencies. This can be achieved by using the same material properties, the same thickness and the same load. In particular, the connection impedance can be referred to as load. The resonance frequency can be detuned by varying this connection impedance.

3 Figure 3 shows an embodiment of a transmission arrangement 1 for the transmission of electrical energy, in which the piezoelectric transducer 2 , 3 through adhesive layers 5 , 6th on the wall 4th are attached. For example, it is an epoxy adhesive. In the case of a transmission arrangement having a detachably attached transducer, for example, only one of the transducers is 2 , 3 through an adhesive layer shown here on the wall 4th attached. The other converter is, for example, according to FIGS 9 and 10 removably attached.

The adhesive layers 5 , 6th can also be designed for acoustic matching, in particular impedance matching, and / or for guiding or focusing the signal in addition to fastening. It can also be provided that between the wall 4th and at least one converter 2 , 3 one in addition to the adhesive layer 5 , 6th existing adaptation layer is present.

The adhesive layers 5 , 6th can also be designed to be electrically conductive. The adhesive layers 5 , 6th can also be used as a contact 29 , 30th for electrical contacting of the converter 2 , 3 be trained. Another contact 31 , 32 is for example on each of the wall 4th remote side of the converter 2 , 3 arranged. The further contact 31 , 32 is for example a sintered metallic layer applied as a paste.

The primary converter 2 is operated with an input voltage V in. The secondary converter produces an output voltage V out.

4th Figure 3 shows an embodiment of a transmission arrangement 1 , with the additional adjustment layers 9 , 10 between wall 4th and the converters 2 , 3 are arranged. It can also only be between one of the converters 2 , 3 and the wall 4th an adaptation layer 9 , 10 to be available. In the case of a transmission arrangement having a detachably attached transducer, for example, only one of the transducers is 2 , 3 through an adhesive layer shown here on the wall 4th attached. The other converter is, for example, according to FIGS 9 and 10 removably attached.

Due to the spatial expansion of the transducer 2 , 3 can be in different locations of the converter 2 , 3 emitted signal components, which are the same when transmitted, hit the wall with different phase positions. The adhesive layer 5 , 6th or adaptation layer can be designed in such a way that the phase positions of all components when entering the wall 4th are as equal as possible, so that destructive interference is avoided as far as possible. The Adhesive layer 5 , 6th is designed in particular in such a way that when the individual signal components are superimposed, an overall signal that is as large as possible results. For example, on a flat wall 4th the adhesive layer is also flat. In the case of an uneven wall, the adhesive layer is 5 , 6th designed for example to compensate for the unevenness, so that all components of the signal with the same phase position on the wall 4th to meet.

In general, in the case of a constant acoustic transit time of the signal components, a constant layer thickness of the adhesive layer can be achieved 5 , 6th or adaptation layer can be provided. In the case of different acoustic propagation times through the layer thickness, a correspondingly different course of the layer thickness can be used for the secondary transducer 3 to achieve an in-phase superposition of all components, ie constructive interference. For example, such different transit times can result from a temperature gradient.

The adhesive layer 5 , 6th or adaptation layer can also be used to guide or focus the signal. For example, a conical widening of the acoustic signal can thus be reduced. For example, the adaptation layer can have an acoustic meta-material. A structured adaptation layer can also be produced by 3-D printing.

5 Figure 3 shows an embodiment of a transmission arrangement 1 where the secondary converter 3 has a larger footprint than the primary transducer 2 . The base is here parallel to the wall 4th arranged outer surface of the transducer 3 . In particular, the diameter is d_s of the secondary converter 3 larger than the diameter d_p of the primary converter 2 . Depending on the base area, this can also be a mean or maximum diameter.

Due to the larger base area, the signal can also be expanded S. , especially in the case of a conical expansion, as large a part as possible of that of the primary transducer 2 emitted acoustic power from the secondary transducer 3 be absorbed and converted into electrical power. In addition, this can also result in a tolerance in the event of an assembly-related offset of the transducers 2 , 3 be achieved.

It can also be one of the converters 2 , 3 removable on the wall 4th be attached. The other properties of the transmission arrangement 1 apply accordingly.

6th shows a base area A. one embodiment a converter 2 for a transmission device 1 .

The base A. is a surface of the transducer 2 that the wall 4th or facing another acoustic medium. This can be a base area of the primary transducer 2 and / or the secondary converter 3 act. For example, the converter 2 , 3 the same footprint A. on. The converters 2 , 3 can also have the same basic shape but a different size, as in 5 shown.

The base A. is designed in the form of a polygon. For example, it is a pentagon. The edges 28 of the polygon are all non-parallel to one another. The polygon thus has no mutually parallel edges, in particular no opposing parallel edges.

In this way, undesired radial-extension modes can be avoided. Radial-extensional modes keep part of the energy supplied on the primary side within the converter and lead to losses. Furthermore, the radial extensional modes can generate disruptive resonance points in the frequency range.

In addition, all edges 28 also have different lengths, so that the occurrence of special resonance modes can be prevented even more efficiently.

7th shows a cross-sectional area Q one embodiment a converter 2 for a transmission device 1 , for example the previous figures. The cross-sectional area Q is the area at a section through the transducer 2 , 3 of the 1 parallel to the plane of the paper.

Those of the wall 4th facing away from the outside 11 has a structured geometry. In particular, the outside 11 at least one depression 12th or elevation 13th on. At the place of depression 12th is the converter 2 thinner than at the point of elevation 13th . In particular, the converter 2 have an elevation circumferentially on the edge or be made thicker. The marginal thickness t_1 of the converter 2 is thus greater than the central thickness t_2 of the converter 2 . The converter 2 can also have a recess all around the edge or be made thinner.

Such a stepped design can minimize acoustic waves on the surface of the wall. These surface waves also lead to losses in the transmission arrangement.

The converters 2 , 3 for example, a combination of the in 6th shown base area with the in 7th have stepped outer surface.

8th shows a transmission arrangement 1 , the primary side and the secondary side next to the respective transducers 2 , 3 has further elements.

The elements can, on the primary side and / or on the secondary side, each in a common converter unit 24 , 25th be arranged. For example, in the case of a detachable converter, the converter unit is 24 , 25th designed to be removable as a whole.

On the primary side 14th is a control electronics 16 available. The control electronics 16 takes up electrical power and converts it into a suitable control signal for the primary converter 2 and sends the signal to the converter 2 from. The control electronics 16 in particular gives an input signal to the primary transducer 2 whose frequency is well adjusted to a resonance frequency. The input signal is, for example, a sinusoidal signal.

For example, the input signal is automatically readjusted depending on ambient conditions, such as temperature, or to compensate for tolerances in production and assembly, so that the input signal is adapted to a changed mechanical-acoustic resonance frequency.

Between the primary transducer 2 and the wall 4th is an acoustic impedance matching 17th arranged. The electrical connection impedance of the transducers 2 , 3 is essential for the impedance matching of the electronic function blocks on the primary side (outer wall) and on the secondary side (inner wall). The impedance matching 17th has for example the adaptation layer 9 according to 4th on or consists of this adaptation layer 9 .

The primary-side elements such as primary control electronics 16 , primary converter 2 and primary impedance matching 17th are for example in a common primary housing 18th arranged.

On the secondary side 15th is for example a secondary impedance matching 17th for acoustic adaptation between the wall 4th and secondary converter 3 available.

In addition, the secondary side 15th a secondary control electronics 20th on which the electrical signal of the secondary transducer 3 converted into regulated electrical power, for example a regulated DC voltage. Optionally, further elements, such as an energy store, can be included.

The secondary-side elements such as secondary control electronics 20th , secondary converter 3 and secondary impedance matching 19th are for example in a common, secondary housing 21 arranged.

9 shows a transmission arrangement 1 where the primary converter 2 and the secondary converter 3 removable from the wall 4th are trained.

The converters 2 , 3 are each on a magnet 22nd , 23 attached. For example, the converters 2 , 3 glued to the respective magnet, for example by means of an epoxy adhesive. These are, for example, NdFeB magnets.

Thus, it has a primary converter unit 24 the primary converter 2 and the primary magnet 22nd on, the secondary converter unit 25th assigns the secondary converter 3 and the secondary magnet 23 on. The primary converter unit 24 and the secondary converter unit 25th each form a unit and can therefore be removed from the wall as a whole 4th be removed.

Between the magnets 22nd , 23 and the wall 4th can each have an adaptation layer 9 , 10 be present as for 4th described. The adjustment layers 9 , 10 can be permanently on the wall 4th to be appropriate. It is also possible to use the adjustment layers 9 , 10 removable on the wall 4th and permanently on the respective converter 2 , 3 to be fortified.

It is also possible to have just one of the converters 2 , 3 design removable. For example, the transducer, which is located in the interior of a housing, is permanently attached and the transducer, which is located in the exterior, is detachably attached. For example, is the secondary converter 3 permanently attached and the primary transducer 2 removably attached.

The magnets 22nd , 23 can be designed to be electrically conductive. The magnets 22nd , 23 can each as a contact 29 , 30th for electrical contacting of the converter 2 , 3 be trained. Another contact 31 , 32 is for example on each of the wall 4th remote side of the converter 2 , 3 arranged.

10 shows a transmission arrangement 1 where the primary converter 2 in a holder 26th is recorded.

The primary converter 2 is particularly removable in the holder 26th recorded and thus removable on the wall 4th attached. The bracket 26th supports the converter 2 down and to the side. The bracket 26th can also have further side surfaces which support the transducer in a direction into and out of the image surface. For example, the converter 2 into the holder from above 26th be inserted. Alternatively, the holder can also be designed similarly to the holder for a button battery cell. In this case, the transducer can be pushed into the holder, for example, perpendicular to the wall.

The bracket 26th has a locking device 27 , for example in the form of a projection. The converter 2 has, for example, a complementary designed latching device, for example a recess. The converter 27 can also through the bracket 26th be held resiliently without a latching device in a recess of the transducer 2 intervenes.

The bracket 26th is on the wall, for example 4th attached by gluing. The bracket 26th can also be screwed on, for example. The bracket 26th is therefore permanently on the wall 4th attached.

The bracket 26th can also function as a contact 29 for electrical contacting of the converter 2 exhibit. further contacts 30th , 31 , 32 can be formed by adaptation or adhesive layers.

Those related to the 1 to 8th The described properties of the transducers and transmission arrangements can be used in accordance with the in the 9 and 10 Detachable transducers shown must be available, provided that this can be reconciled with the properties described.

In addition, in the 1 to 8th Transmission arrangements instead of a fixed wall also have another medium, provided that this can be reconciled with the properties described.

List of reference symbols

1

Transfer arrangement

2

primary converter

3

secondary converter

4th

wall

5, 6

Adhesive layer

7, 8

further adhesive layer

9, 10

Adaptation layer

11

Outside

12th

deepening

13th

Elevation

14th

Primary side

15th

Secondary side

16

primary control electronics

17th

primary impedance matching

18th

primary housing

19th

secondary impedance matching

20th

secondary control electronics

21

secondary housing

22nd

primary magnet

23

secondary magnet

24

primary converter unit

25th

secondary converter unit

26th

bracket

27

Locking device

28

Edge

29

Contact

30th

Contact

31

Contact

32

Contact

S.

Signal expansion

t_p

Thick primary transducers

t s

Secondary transducer thickness

t_1

first thickness

t_2

second thickness

t_W

Thick wall

d_p

Primary transducer diameter

d_s

Secondary Transducer Diameter

Δf

Distance between frequency peaks

T

transmission

F.

Fourier transform of the impulse response

f

frequency

V_in

V_out

A.

Floor space

Q

Cross sectional area

QUOTES INCLUDED IN THE DESCRIPTION

This list of the 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 assumes no liability for any errors or omissions.

Non-patent literature cited

• Ding-Xin Yang, Zheng Hu, Hong Zhao, Hai-Feng Hu, Yun-Zhe Sun and Bao-Jian Hou: "Through-Metal-Wall Power Delivery and Data Transmission for Enclosed Sensors: A Review" in Sensors 2015, 15, 31581-31605 [0008]

Claims (15)

Transmission arrangement comprising a primary piezoelectric transducer (2), a secondary piezoelectric transducer (3) and a wall (4) for transmitting an acoustic signal between the transducers (2, 3), at least one of the transducers (2, 3) being detachable the wall (4) can be fastened. Transfer order according to Claim 1 , comprising a magnet (22, 23) for magnetic attachment of the removable transducer (2, 3) to the wall (4). Transfer order according to Claim 2 , wherein the magnet (22, 23) is designed as a contact for making electrical contact with the transducer (3). Transmission arrangement according to one of the preceding claims, having an adaptation layer (9, 10) for adapting phase positions and / or for guiding the acoustic signal. Transmission arrangement according to one of the preceding claims, wherein the adaptation layer (9, 10) is arranged between the wall (4) and at least one of the transducers (2, 3). Transmission arrangement according to one of the preceding claims, wherein the adaptation layer (9, 10) is designed as a gel. Transmission arrangement according to one of the preceding claims, wherein the adaptation layer (9, 10) has different thicknesses and / or a structured surface. Transmission arrangement according to one of the Claims 6 or 7th , in which the adaptation layer (9, 10) comprises an acoustic meta-material. Transmission arrangement according to one of the preceding claims, wherein the secondary transducer (3) has a larger base area than the primary transducer (2). Transmission arrangement according to one of the preceding claims, in which at least one of the transducers (2, 3) has a geometry which is designed to reduce undesired oscillation modes. Transfer order according to Claim 10 , in which at least one of the transducers (2, 3) has a base area (A) in the form of a polygon, the polygon being free of mutually parallel edges. Transmission arrangement according to one of the Claims 10 or 11 , in which at least one of the transducers (2, 3) has different thicknesses (t_1, t_2). Transfer order according to Claim 12 , in which at least one of the transducers has a greater thickness at the edge than in a central area. Transmission arrangement according to one of the preceding claims, having control electronics for adapting an input signal to a resonance frequency. Transmission arrangement comprising a primary piezoelectric transducer (2), a secondary piezoelectric transducer (3) and a wall (4) for transmitting an acoustic signal between the transducers (2, 3), at least one of the transducers (2, 3) being magnetic or mechanically attached to the wall (4).

Images